Tesi: "Sex estimation"

1

Rennie, S. R. "Summary sex : a multivariate approach to sex estimation from the human pelvis". Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/9471/.

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With the progression of multivariate statistics, the creation of population specific equations is on the rise. Multivariate analysis generally revolves around metric methods or geometric morphometrics, not on morphoscopic features. A total of eight samples were analysed spanning from prehistoric American to modern day South African and ranged between pygmy populations from the Andaman Islands to medieval British populations. With a sample size of more than 1100 individuals, each os coxa was scored using eight morphoscopic features most commonly used by physical anthropologists and osteoarchaeologists. Trait frequencies were compiled and compared between each of the eight samples. Then, the samples were placed into two groups: a known age and sex group (Christ Church Spitalfields, South African White, South African Black, and South African Coloured), and an unknown archaeological group (Poulton, St. Owens, Chumash, and Andaman). When comparing trait frequencies, slight differences between the samples could be seen. Ordinal Logistic Regressions (OLR) were applied onto each of the four samples from the known age and sex group to create population specific sexing equations (cross-validated). Results from these four equations ranged from 90.24% (South African Black population specific equation) to 96.38% (Christ Church, Spitalfields population specific equation). Population specifity was tested by applying all of the equations onto each sample in this group. In an attempt to reduce this, two new equations were created by combining samples together resulting in a South African specific equation (92.54% accuracy) and a "Summary Sex" equation (92.98% accuracy). After applying each of the six new OLR equations onto the four archaeological samples, high percentage accuracies (ranging from 92.59% to 100.00%) were found when comparing them to the previous records. The only sample that did not produce as high of an accuracy was the Chumash sample with 82.35%. In the attempt to analyse fragmented remains, three avenues were taken. Firstly, all missing values were replaced by the median score. Secondly, the original six OLR equations were 'sectioned' to make three smaller sets of equations. Lastly, to mirror the sectioned equations, three new sets of OLR equations were generated. This study shows that when using morphoscopic traits for sex estimation, applying multivariate techniques can be used to obtain a high accuracy even when dealing with fragmented samples.

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Cleary, Megan Kathleen. "Sex Estimation from the Clavicle: A Discriminant Function Analysis". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/781.

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AN ABSTRACT OF THE THESIS OF MEGAN K. CLEARY, for the Master of Arts degree in ANTHROPOLOGY, presented on MARCH 28th at 8am, at Southern Illinois University Carbondale TITLE: SEX ESTIMATION FROM THE CLAVICLE: A DISCRIMINANT FUNCTION ANALYSIS MAJOR PROFESSOR: Dr. Gretchen R. Dabbs The development of methods for sex estimation using postcranial remains other than the os coxa is imperative for physical anthropology to improve the reliability of biological profile estimates in cases of incomplete and/or fragmentary skeletal remains. As the last skeletal element to complete fusion, the clavicle has the longest period of time to develop sexually dimorphic features, making it an ideal skeletal element for use in sex estimation. Sexual dimorphism in the clavicle was assessed using 18 measurements of the left clavicle of 265 (129 females; 136 males) individuals from the Hamann-Todd Collection. Independent samples t-tests with Bonferroni correction show males and females differ at a statistically significant level for all 18 variables with a significance level of 0.0028. Discriminate function analyses using the stepwise method (0.05 to enter, 0.10 to exit) produced a four variable model with cross-validated accuracy of 89.8%. A holdout sample from the Hamann-Todd Collection (n=30) similar in demographic character to the calibration sample was tested using the four variable model. The accuracy of the four variable model on the holdout sample was 90.0%. Additionally, four single variable models developed to accommodate fragmentary remains also have high predictive power (75.1-82.3% cross-validated calibration sample; 60.0-86.7% hold-out sample).

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3

Casado, Ana Maria. "Evaluation of Features of the Innominate for Sex Estimation". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275064778.

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4

Rector, Jacquelyn N. "Sex estimation method using cervical canine diameters: a validation study". Thesis, Boston University, 2013. https://hdl.handle.net/2144/21246.

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Thesis (M.S.F.S.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
This thesis presents a validation study of the research by Hassett (2011). It examined the permanent canines’ cervical diameters using established measurement techniques set forth by Hillson et al. (2005) to determine sex in a known population of male and female adults and juveniles. The present study combined the Maxwell Collection, housed at University of New Mexico, and the Hamann-Todd Collection, housed at the Cleveland Museum of Natural History, as the known-sex sample. The sample included 642 permanent canines resulting in 862 measurements from 218 individuals. There were 120 males and 98 females between the ages of 12 and 98 years old. Of the 218 individuals, 148 were White, 62 were Black, 2 were Hispanic, 1 was Native American, and 5 were an unknown ancestry. The measurements used were the cervical mesiodistal diameter and the cervical buccolingual diameter of each upper and lower, right and left canine. The author hypothesized that research conducted on this known age skeletal collection sample would support Hassett (2011), who concluded that the cervical diameter of the canine is sexually dimorphic and can be used to predict sex accurately. In addition, it was predicted that there would not be a significant statistical difference between adult and juvenile permanent canine measurements. An intra-observer error test found that original and repeated measures were not statistically different from one another. Statistical analysis found that adults and juveniles did not have significantly different measurements, so the two samples were combined into one larger known-sex sample. The accuracy of all the functions for both sexes using the cervical diameter method is between 80.2% and 87.5%. The fourth function’s formula, which uses both diameters from one maxillary canine and one mandibular canine, had the best overall accuracy of 87.1%. The accuracy of all the functions for males was between 81.1% and 91.7% and for females the accuracy was between 74.8% and 89.7%. Analysis also indicated that no tooth nor measurement proved to be a better predictor of sex; therefore, any tooth and measurement can be used to estimate sex. The author believes that this validation will allow further research into the applicability of the permanent canine using cone-beam computed tomography to determine sex in juveniles whose permanent canines have not yet erupted. This determination is highly significant, given the dearth of usable techniques to sex juvenile human remains.
2031-01-01

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5

Harrison, Donna. "An evaluation of the methods used in the estimation of sex". Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1545099/.

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Sex estimation is a fundamental component of demographic information for skeletal collections. When collections are undocumented, it is important to have established and accurate methods to determine sex. Many methods have been used since the 1800s. These methods, both morphological and metric, primarily focus on estimating sex on the pelvis, cranium, mandible, humerus and femur. The aim of this research is to establish which types of methods and which major bones are the most accurate for identifying sex in skeletons, especially when the pelvis is in poor condition or missing. A total of 67 morphological and metric methods were assessed on 294 adults from four diverse known sex samples. The study included assessment of 23 methods on 120 juveniles from two of the samples. The results indicate that while morphological methods are a reliable tool to sex adult skeletons, there are metric methods that are equally reliable, especially in the absence of the pelvis. Initial research in sex estimation of juveniles yielded several methods which scored over 75% accuracy when the samples were broken down into five distinct age groups. The study also demonstrated other possible uses for sex estimation, such as measuring variability in bones through hyper-sex codes (-2, +2) used in morphological methods, exploration of gender identification presented in two case studies, and exploring the effect of skeletal adaptation from occupation on sexual dimorphism in two African-American samples who share a common history but lived in different geographical locations.

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6

Kazzazi, Seyedeh Mandan. "Dental metric standards for sex estimation in archaeological populations from Iran". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31067.

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Sex estimation of skeletal remains is one of the major components of forensic identification of unknown individuals. Teeth are a potential source of information on sex and are often recovered in archaeological or forensic contexts due to their post-mortem longevity. Currently there is limited data on dental sexual dimorphism of archaeological populations from Iran. This dissertation represents the first study to provide a dental sex estimation method for Iron Age populations. The current study was conducted on the skeletal remains of 143 adults from two Iron Age populations in close temporal and geographic proximity in the Solduz Valley (West Azerbaijan Province of Iran). 2D and 3D cervical mesiodistal and buccolingual and root volume measurements of maxillary and mandibular teeth were used to investigate the degree of sexual dimorphism in permanent dentition and to assess their applicability in sex estimation. In total 1327, 457, and 480 anterior and posterior teeth were used to collect 2D cervical, 3D cervical, and root volume measurements respectively. 2D cervical measurements were taken using Hillson-Fitzgerald dental calliper and 3D measurements were collected using CT images provided by Open Research Scan Archive (ORSA) - Penn Museum. 3D models of the teeth were created using manual segmentation in the Amira 6.01 software package. Since tooth density largely differs from crown to apex, root segmentation required two threshold levels: the segmentation of the root from the jaw and the segmentation of the crown from the root. Thresholds used for root segmentation were calculated using the half maximum height protocol of Spoor et al. (1993) for each skull, and thresholds used for crown segmentation were set visually for each tooth separately. Data was analysed using discriminant function analysis and posterior probabilities were calculated for all produced formulae where sex was previously assessed from morphological features of pelvis and skull. Bootstrapping was used to account for small sample sizes in the analysis. Statistical analysis was carried out using SPSS 23. The percentage of sexual dimorphism was also used to quantify the amount of sexual dimorphism in the sample. The results showed that incisors and canines were the most sexually dimorphic teeth, providing percentages of correct sex classification between 80% and 100% depending on the measurement used. Root volume measurement was shown to be the most sexually dimorphic variable providing an accuracy of over 90% in all functions. The present study provided the first dental metric standards for sex estimation using odontometric data in Iranian archaeological populations. Dental measurements, particularly root volume measurements, were found to be of value for sex assessment and the method presented here could be a useful tool for establishing accurate demographic data from skeletal remains of the Iron Age from Iran.

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7

Rodriguez, Maria. "TIME ESTIMATION AND HAND PREFERENCE". Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3895.

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This work examines the effect of participants' gender and handedness on the perception of short intervals of time. The time estimation task consisted of an empty production procedure with forty trials at each of four intervals of one, three, seven, and twenty seconds. The four target intervals represent a natural logarithmic progression and a series that bracket important temporal thresholds. The order of presentation of those intervals was randomized across participants but yoked across the sexes in each of the respective dominant hand groups. The two between-subject factors, with two levels each, were sex and handedness. Participants produced forty estimates at each of the required intervals, which was the first within-subject factor, estimated interval being the other. T-tests were conducted on the dependent measures, the time estimates in terms of their variability and their central tendency with respect to the target duration. If handedness plays a significant role in timing, this may indicate differences between hemispheric functioning as a possible causal mechanism. If there is cerebral asymmetry in time perception, namely if one hemisphere is more competent regarding time perception, accuracy in judging duration should be higher for the contralateral hand. The results of the present study indicated that there are no significant differences in performance between right-handed and left-handed participants, or between male and female participants, in the estimation of short intervals of time.
Ph.D.
Department of Psychology
Arts and Sciences
Psychology

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8

Lubsen, Kyle Douglas. "THE DEVELOPMENT OF SEX ESTIMATION METHODS IN FOUR PREHISTORIC NATIVE AMERICAN SKELETAL SAMPLES". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/482.

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Sex estimation in bioarchaeological research is paramount for comparative analyses of skeletal remains and developing estimates of other demographic variables. Frequently, sex is estimated utilizing the morphology of pelvic and cranial bones in archaeological skeletal samples. Regrettably, these bones are often damaged, destroyed, or lost and cannot be employed for the estimation of sex. Fortunately, a variety of metric and visual sex estimation methods have been developed on modern skeletal samples with known demography. Disappointingly, due to the population specific nature of many of these metric methods, they cannot be accurately applied directly to alternate skeletal samples. However, these methods can be redeveloped and retested for archaeological skeletal samples if the proper protocol is utilized. This research utilizes the protocol for developing methods of sex estimation on samples with unknown sex developed by Murail et al. (1999). Utilizing select hand and foot bones from four prehistoric Native American skeletal samples from Alabama and Illinois, multiple discriminant functions were developed and tested on both Archaic and Mississippian Period skeletal samples. Furthermore, the four individual site samples were combined into two geographical and two temporal samples, as well as an all pooled sample in order to test the broader applicability of these methods. The results indicate that sex estimation methods can be developed on samples where sex is not known. Additionally, the discriminant functions developed produce high levels of classification for the sites, individually, as well as for the geographic, temporal, and all pooled samples. The latter suggests these functions have broader applicability for these regions and temporal periods. Moreover, the concordance rates for these functions are similar to the accuracy rates when these bones were applied to samples with known sex.

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9

Foltz, Christine D. "Sex estimation through discriminant function analysis of an archaeological population from Mistihalj, Montenegro". Thesis, Boston University, 2013. https://hdl.handle.net/2144/12101.

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Thesis (M.S.)--Boston University
In an effort to create discriminant function equations for a spatially and temporally specific archaeological population, this study utilized metric analyses of the crania and post-crania in a collection from Mistihalj, Montenegro housed at the Peabody Museum of Archaeology and Ethnology. After the data was collected, discriminant function analyses were performed and used in the creation of univariate and multivariate sectioning points for the purpose of estimating the sex of archaeological populations in this region. It is believed that the equations created will supplement other bioarchaeological methods for sex estimation within archaeological populations of the Balkan region where single skeletal elements or commingled remains may be prominent. This project will also provide a better understanding of sexual dimorphism in Balkan populations, which may ultimately help when working to make a biological profile for an unknown individual in this region. The best univariate measures for sex estimation (ranging from 96% to 85% accuracy) are: maximum diameter of the femur head, sagittal diameter of the radius at midshaft, maximum length of the ulna, maximum vertical diameter of the head of the humerus, biauricular breadth, maximum length of the radius, epicondylar breadth of the femur, anterio-posterior diameter of the femur at midshaft, maximum length of the humerus, maximum length of the calcaneus, bizygomatic breadth, and maximum epiphyseal breadth of the proximal tibia. All multivariate equations achieved classification rates above 85%. The best elements for multivariate analysis (above 90% accuracy) are: femur, radius, humerus, cranium, tibia, and ulna. Unexpectedly, two cranial measures are among the most accurate univariate measures, and the cranium provided higher classification rates than expected in comparison to post-cranial elements in the multivariate analyses. The multivariate equations created are only applicable if every measure/landmark required is present on the skeleton in question. As there is often differential preservation of skeletal elements, the use of multiple univariate sectioning points may be better on moderately or very poorly preserved remains.

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10

Phillips, Vincent. "Sex estimation using the diagonal diameter measurements of first mandibular molars in a Sudanese sample". University of the Western Cape, 2020. http://hdl.handle.net/11394/7531.

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Magister Scientiae Dentium - MSc(Dent)
Sexual identification of immature skeletal remains is still a complicated issue to solve in Forensic Anthropology. Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. (1) The aim of this study is to evaluate the existence of sexual dimorphism in mandibular first molars. The base sample of the study includes 300 Sudanese (150 males and 150 females). Their ages ranged from 17 to 55. The mesio-buccal (MB) disto-lingual (DL) and the mesio-lingual (ML) disto-buccal (DB) surfaces of the mandibular first molars were measured using a digital Vernier caliper on plaster of Paris study casts. The data was analyzed using the t-test. The results showed statistically significant sexual dimorphisms in male and female odontometric features. The mean values of the parameters were greater in males than in females in both (MBDL and MLDB) with greater sexual dimorphism in the MBDL (MBDL dimorphism =28.672 %) than the MLDB (MLDB dimorphism =21.596 %). Conclusion: Sexual dimorphism of 1st molar teeth can aid in the identification of skeletal remains of Sudanese origin.

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11

Gonzales, Paola Sampaio. "Análise facial fotoantropométrica de adultos jovens brancos brasileiros". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/23/23153/tde-15082018-101346/.

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A antropometria é o estudo das medidas do corpo. A medição pode ser realizada no próprio corpo, na chamada técnica direta, ou na representação do indivíduo, na técnica indireta. Os resultados podem ser aplicados nas áreas da medicina, odontologia, fisioterapia, fonoaudiologia, entre outros. A antropometria aplicada à face traz dados referentes ao crescimento, ao envelhecimento e é capaz de traçar características de tecidos moles. É consenso na literatura que não há um padrão facial único que possa servir para todas as populações, sendo que cada uma possui características que as tornam únicas e que devem ser levadas em consideração no planejamento de cirurgias estéticas, ortognáticas e reconstrutivas. Até o momento, não há estudos que tragam o detalhamento antropométrico da face da população brasileira. Assim, o objetivo geral desse trabalho é trazer o levantamento antropométrico facial da população de adultos jovens brancos brasileiros por meio da análise de fotografias em norma frontal, método conhecido como fotoantropometria. As fotografias têm origem de um banco civil de imagens da Polícia Federal brasileira, sendo 689 de indivíduos do sexo feminino (F) e 660 do sexo masculino (M). Foram selecionadas as imagens que possibilitavam a visualização dos pontos fotoantropométricos de interesse e que apresentavam a centralização da cabeça em relação ao plano sagital, ao plano horizontal e ao eixo sagital. Os indivíduos representados nas fotografias foram classificados quanto à ancestralidade levando-se em consideração aspectos como cor da pele, textura do cabelo e morfologia nasal e labial. Os pontos fotoantropométricos foram marcados manualmente nas imagens fotográficas por meio do software SAFF 2D®. As coordenadas em pixels foram transformadas em distâncias lineares e deram origem aos índices, os quais foram analisados sob diversos aspectos. Além das análises realizadas para a população total, os indivíduos foram separados em grupos, considerando-se o sexo e o local de nascimento correspondente às regiões do país, sendo: Sul, Sudeste, Centro-oeste, Nordeste e Norte. A morfologia da face da população de adultos jovens brancos do Brasil foi exaustivamente analisada sob vários aspectos e foi possível concluir que há diferença na morfologia facial entre os sexos e regiões de nascimento. O estudo ainda mostra qual a acurácia dos índices para a estimativa de sexo e predição da região de nascimento. Estudos futuros devem ser realizados para as demais ancestralidades que compõem a população do Brasil.
Anthropometry is the scientific study of the measurements of the human body. These measurements can be performed directly on the body or indirectly on the images of individuals. Their findings can be used in areas such as medicine, dentistry, physical therapy, and speech therapy, among others. Facial anthropometry provides information on growth and aging and can be used to outline characteristics of soft tissues. A consensus agreement has been reached in the literature that there is not a single facial pattern that fits all populations, as each population has unique features that should be taken into account in the planning of esthetic, orthognathic, and reconstructive surgeries. To date, no studies in Brazil have conducted an extensive investigation into the facial pattern of the Brazilian population. Therefore, the overall aim of this study is to carry out a photoanthropometric analysis of the population of young adult white Brazilians by analyzing frontal photographic images. The photographs were obtained from the Brazilian Federal Police image database and include 689 female (F) and 660 male (M) individuals. The images that allowed observing the anthropometric parameters of interest and on which the head had been placed centrally to the sagittal plane, to the horizontal plane, and to the sagittal axis were selected. The individuals depicted on the photographs were classified as to ancestry based on aspects such as skin color, hair texture, and nose and lip morphology. Anthropometric landmarks were made manually on the photographic images using the SAFF 2D® software program. The pixel coordinates were converted to linear distances, giving rise to indices, which were assessed with respect to various aspects. In addition to the analyses of the total population, individuals were categorized into groups according to sex and region of birth (south, southeast, midwest, northeast, or north). The facial morphology of the population of young adult white Brazilians was analyzed comprehensively as to different aspects, leading to the conclusion that facial morphology varies between the sexes and across regions of birth. The study also shows the accuracy of the indices for sex assessment and for prediction of the region of birth. Further studies are needed to evaluate other ancestries that make up the Brazilian population.

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Gulhan, Oznur. "Skeletal sexing standards of human remains in Turkey". Thesis, Cranfield University, 2017. http://dspace.lib.cranfield.ac.uk/handle/1826/12272.

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The identification of victims involved in mass fatality incidents, as well as the identification of unknown individuals in criminal cases has become an increasingly important issue nowadays. Sex assessment represents a key point in forensic evaluations due to its significance in providing biological identity. Even though the availability of documented skeletal remains to forensic practitioners is a common practice in many countries, in Turkey, contemporary documented skeletal remains are not available for this purpose. For this reason, studies have been focused on living populations. Previous research has shown that modern technologies such as CT scanning present very promising potential in establishing new standards for contemporary populations. Therefore, the main aim of this project was to examine the application of the measurements taken from 3D CT images of the femur in order to assess sex, and to contribute to the establishment of discriminant function equations for the Turkish population for forensic applications. The accuracy and reproducibility of imaging methods in the assessment of the measurements taken from femora are essential when estimating sex. This research also concentrated on determining the accuracy and repeatability of CT measurements, using the femur. Prior to primary data collection, a preliminary study was performed in an effort to test the reliability of the femur measurements. The results of reliability analysis indicated no significant difference between the three observations of each measurement. Thus, the methodology employed in the current study appears reliable and reproducible. In addition, a validation study was conducted to determine the linear measurement accuracy of the 3D volume rendering models derived from a medical CT scanner and the influence of different reconstruction parameters. The differences between measurements obtained from dry bones and their 3D volume rendered models were also evaluated. The results from this study indicated that there were no statistically significant differences between measurements taken from different reconstruction parameters and measurements obtained from CT images and drybones. Using the CT data, volume-rendering function (VR), 3D Curved Multiplanar reconstruction (MPR), and Scout View on OsiriX were employed in order to compare the accuracy and reliability of each rendering method and to determine which technique is optimal for linear measurements. Overall, the measurements taken from the 3D Volume Rendering images had the highest intra-observer reliability when compared to the other two rendering methods. This research study produced data and interpretations that will inform on and improve population specific standards of sex assessment from three-dimensional postcranial osteometric landmarks. Additionally, this research is believed to provide value for a developing discipline of forensic anthropology, and integrate within the existing systems of criminal investigation and disaster victim identification practices in Turkey. A Turkish sample population, consisting of 300 adult hospital patients was examined via the interpretation of CT reconstructed images using the OsiriX software. The 3D reconstructions were then created using the volume-rendering function in OsiriX (v.5.6.). Following the 3D reconstruction, an image of each femur was segmented from the surrounding bones to ensure the correct usage of landmarks as accurately as possible. Thirteen measurements were acquired using a 3D viewer after being located and marked on each CT reconstructed femora. These thirteen anthropometric parameters were measured and analysed by basic descriptive statistics and discriminant analysis methods using the SPSS 21.0 software package. The intra-observer variation was assessed by obtaining the intraclass correlation coefficient in order to evaluate the accuracy of the linear measurements taken. Asymmetry was also tested. The results indicated that an accuracy of 92.3% was acquired from a combination of six of the measurements, and the Femur Vertical Diameter of Neck (FVDN) measurement was found to be the most dimorphic with 88.0% accuracy.

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Pedrosi, Maria Elena <1982&gt. "Age Estimation and Sex Determination in Human Skeletal Remains. A Test of the Common Methods Used in Anthropology for Sex Determination and Age Estimation Applied to Identified Human European Skeletal Collection (Bologna, Coimbra 19th-20th C.)". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7488/.

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One of the main problems in reconstructing the biological profile of unidentified human remains is the reliability of the methods used. These methods are normally developed on modern identificated human skeletal collections, but human variability can introduce problematic biases when applied on osteological collections from different geografical and cronological contexts. This study test the reliability of selected macroscopic methods for sex determination: the index of sexualization of Acsadi and Nemeskeri, the Phenice method and for the age estimation: the synostosis of cranial sutures (Meindl and Lovejoy), the morphological variations at the pubic symphysis (Suchey and Brooks), the morphological variations at ileum surface (Lovejoy, et al.), the modifications of the sternal end of the fourth rib (Iscan et al.) and the variations of the degree of sacral vertebral body fusion (Belcastro et al.) on a large sample (n.489) of know sex and age from Certosa Cemetery of Bologna and “Colecção Esqueletos Identificados" of Coimbra. Regarding age, for each method was calculated the standard values of bias and inaccuracy. The method of pubic symphysis might be the most reliable for age estimation but we must consider the width of age ranges considered by the method. The values of inaccuracy are over 10 years in individuals older than 50 and 27 years in individuals older than 60. The index of sexualization confirm in more than 99% of cases the known sex and the Phenice method gave good results with the 87% of confirm. The reliability of the tested methods in the two european populations was confirmed, with the pelvis as the most diagnostic district, in particular the pubic symphysis. Nevertheless, the dramatic increase in values of bias and inaccuracy with increasing age confirms the need for new or revised age estimation methods that better suits the study of the remains of older individuals.

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Voisin, Meghan Dawn. "Sexual dimorphism in the 12th thoracic vertebra and its potential for sex estimation of human skeletal remains". Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/3991.

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The purpose of this study is to determine the presence/degree of sexual dimorphism of the 12th thoracic vertebra through a quantitative analysis and to further examine its potential and reliability in the sex estimation of human skeletal remains. This study also explores the age-related changes of human skeletal remains and how these affect morphological variation conducive to sex estimation. In order to assess this, the 12th thoracic vertebrae, femur and sacrum of 168 mature skeletal remains (94 males and 74 females) from the Raymond Dart Collection in Johannesburg, South Africa and 407 (205 males and 202 females) mature skeletal remains from the Hamann-Todd Collection in Cleveland, Ohio were analyzed. Only individuals whose group affiliation was designated as “South African Black” from the Raymond Dart Collection and “African American” from the Hamann-Todd Collection were measured. This was done to permit the examination of geographical variance within and between the two samples. The morphology of the 12th thoracic vertebra was examined by means of univariate and multivariate analyses to better assess each effect. These analyses resulted in relatively high correct classifications of males and females in all samples, with mean measurement values being larger in males in all measurements. While age-related changes have little effect on the high reliability of sex estimation in the African American sample, age-related changes decreases the reliability of sex estimation in the South African sample. Overall, this study reveals that the 12th thoracic vertebra has potential for use in sex estimation as a result of the skeletal morphological variation between males and females both documented in the Raymond A. Dart Collection of Human Skeletons and the Hamann-Todd Osteological Collection.
Thesis (M.A.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Anthropology.

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Chapman, Erin Nicole. "A Study of Biological Sex Estimation Across Populations Using Measurements of the Cementoenamel Junction and Dental Arcade". Thesis, State University of New York at Buffalo, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10284576.

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Biological sex estimation has been a central tenant in physical anthropology and bioarchaeology since the foundation of the fields. Traditionally, sex estimation techniques have centered on pelvic morphology but features of the pelvis are often poorly preserved in forensic and archaeological contexts. However, teeth have very high preservation potential. Because the crown is susceptible to ante- and postmortem damage, the cementoenamel junction (CEJ) provides a more often preserved portion of the tooth. Several studies have shown the potential use of measurements of the CEJ in biological sex estimation; however, these studies have been limited in their scope, samples sizes, and materials utilized. Additionally, the role of biological affinity in the estimation of biological sex from measurements of the CEJ have not been fully explored. Three main goals of the present study are: 1) to assess the ability to estimate biological sex from measurements of the cementoenamel junction across populations; 2) to assess the role of biological affinity in sex estimation based on the measurements of the cementoenamel junction across populations; and 3) to examine the relationship between dental arcade size and biological sex within and between populations.

A total of 737 dentitions (7,369 teeth) from American and South African Whites and Blacks were measured based on buccal-lingual and mesial-distal CEJ measurements defined by Hillson and colleagues (2005). Percent dimorphism was calculated for buccal-lingual, mesial-distal and geometric mean measurements for each tooth. Percent dimorphism was highest in the canines for all groups. Discriminant function and logistic regression analyses were run to assess the ability of the measurements to correctly classify biological sex within and between populations and groups. Correct classification ranged from 84.1% to 90.7%. Within group comparisons (i.e., American females, South African males, etc.) highlighted that molars, premolars, and incisors have the greatest weight in the discriminant function in classifying differences between ancestral groups.

Finally, a total of 162 dental arcades (maxillary and mandibular) were measured from photographs using ImageJ software to assess differences in dental arcade size and to assess the relationship between mesial-distal measurements of the CEJ and the length of the dental arcade. Statistically significant differences in mean arcade size were found for all groups except South African Whites and South African Blacks (mandible only). Pearson’s correlation coefficient tests were used to test if a correlation existed between the sum of the mesial-distal CEJ measurements and the total arc length. A significant correlation was found in all groups except American Whites, South African Whites, and All Whites combined (mandible only). In summary, the buccal-lingual and mesial-distal measurements of the CEJ can be used to estimate biological sex with a high degree of correct classification. Canines, specifically the lower canine, shows the highest percent of sexual size dimorphism for all groups. Lower overall sexual size dimorphism is noted in the South African groups, especially South African Whites, when compared with their American contemporaries. Results indicate that the size (and possibly the shape) of molars, premolars and incisors have the most influence on differences seen between ancestral groups.

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16

Stull, Kyra Elizabeth. "An osteometric evaluation of age and sex differences in the long bones of South African children from the Western Cape". Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/40263.

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The main goal of a forensic anthropological analysis of unidentified human remains is to establish an accurate biological profile. The largest obstacle in the creation or validation of techniques specific for subadults is the lack of large, modern samples. Techniques created for subadults were mainly derived from antiquated North American or European samples and thus inapplicable to a modern South African population as the techniques lack diversity and ignore the secular trends in modern children. This research provides accurate and reliable methods to estimate age and sex of South African subadults aged birth to 12 years from long bone lengths and breadths, as no appropriate techniques exist. Standard postcraniometric variables (n = 18) were collected from six long bones on 1380 (males = 804, females = 506) Lodox Statscan-generated radiographic images housed at the Forensic Pathology Service, Salt River and the Red Cross War Memorial Children’s Hospital in Cape Town, South Africa. Measurement definitions were derived from and/or follow studies in fetal and subadult osteology and longitudinal growth studies. Radiographic images were generated between 2007 and 2012, thus the majority of children (70%) were born after 2000 and thus reflect the modern population. Because basis splines and multivariate adaptive regression splines (MARS) are nonparametric the 95% prediction intervals associated with each age at death model were calculated with cross-validation. Numerous classification methods were employed namely linear, quadratic, and flexible discriminant analysis, logistic regression, naïve Bayes, and random forests to identify the method that consistently yielded the lowest error rates. Because some of the multivariate subsets demonstrated small sample sizes, the classification accuracies were bootstrapped to validate results. Both univariate and multivariate models were employed in the age and sex estimation analyses. Standard errors for the age estimation models were smaller in most of the multivariate models with the exception of the univariate humerus, femur, and tibia diaphyseal lengths. Univariate models provide narrower age estimates at the younger ages but the multivariate models provide narrower age estimates at the older ages. Diaphyseal lengths did not demonstrate any significant sex differences at any age, but diaphyseal breadths demonstrated significant sex differences throughout the majority of the ages. Classification methods utilizing multivariate subsets achieved the highest accuracies, which offer practical applicability in forensic anthropology (81% to 90%). Whereas logistic regression yielded the highest classification accuracies for univariate models, FDA yielded the highest classification accuracies for multivariate models. This study is the first to successfully estimate subadult age and sex using an extensive number of measurements, univariate and multivariate models, and robust statistical analyses. The success of the current study is directly related to the large, modern sample size, which ultimately captured a wider range of human variation than previously collected for subadult diaphyseal dimensions.
Thesis (PhD)--University of Pretoria, 2013.
gm2014
Anatomy
unrestricted

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17

Phillips, Chase Elizabeth Buckingham. "The use of craniometrics in the estimation of juvenile sex by means of discriminant function analysis: a revised method". Thesis, Boston University, 2013. https://hdl.handle.net/2144/12187.

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Thesis (M.S.)--Boston University
This study provides evidence that there is sex dimorphism within the craniofacial growth of juveniles. This study was modeled after the study produced by Gonzalez (2012) and updates the methodology used in that study. Computed tomography (CT) images of 351 juvenile individuals, ages three to sixteen, both male and female, from the Department of Radiology at Boston University School of Medicine were measured. Of the twenty six measurements taken, nineteen were used for analysis. Measurements were made using OsiriX, an open-source software that allows the manipulation and measurement of CT images. The data was analyzed using discriminant function analysis in order to make classification models based on age groups. Gonzalez’s study showed that the male head is both taller and longer than a female’s and that based on his data set, sex estimation using this method is 78 to 89% accurate. The current study exhibited rates from 66-85% correct classification depending on the age group when analyzed with a stepwise analysis and rates of 74-92% when analyzed without; both analyses exhibited a trend towards improved classification rates in the older individuals. The neurocranium and the areas affected by the growth of the nasopharynx were found to be the most dimorphic. In general, males tend to have a longer and wider neurocrania as well as increased growth in the anterior direction of the facial region. In addition females had higher correct classification rates compared to males, despite having fewer females within the sample collection; this trend was also reflected in the original results produced by Gonzalez.

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18

Thompson, Clarissa Ann. "The Representational Alignment Hypothesis of Transfer of Numerical Representations". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211376719.

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19

Tardivo, Delphine. "Détermination de l'âge et du sexe et modélisation de la canine en anthropologie médico-légale". Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20705.

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Les méthodes osseuses de diagnose sexuelle donnent d’excellents résultats, avec des taux de bonnes prédictions du sexe supérieurs à 90%. Néanmoins, les éléments osseux ne sont pas toujours disponibles et, lorsqu’ils le sont, selon les causes de la mort et/ou les conditions de conservation du corps, ils peuvent avoir été lourdement dégradés. Pour parvenir à déterminer le sexe d’un individu dans ces situations là, des techniques dentaires de diagnose sexuelle sont nécessaires.Contrairement à la détermination du sexe, la problématique de la détermination de l’âge a fait l’objet de nombreuses études et d’autant de propositions de techniques différentes, signe d’une insuffisance de l’ensemble de ces méthodes, que la littérature n’a pas manqué de mettre en exergue.Le premier objectif de ce travail est de proposer une technique dentaire de détermination du sexe simple et précise, de façon à pouvoir répondre à cette problématique anthropologique de façon fiable en l’absence d’autres éléments du squelette.Le second est de développer une méthode d’estimation de l’âge de mise en œuvre facile, rapide et ne nécessitant ni un plateau technique lourd, ni la détérioration du matériel, pour une application aussi bien anthropologique que médico-légale. L’échantillon d’apprentissage était composé de 210 scanners d’individus présentant chacun 4 canines saines. L’échantillon d’application était composé de 55 scanners d’individus, présentant chacun au moins 1 canine saine. Les volumes pulpaire et total de chaque dent ont été modélisés et calculés à l’aide du logiciel Mimics. Une régression logistique binaire a été utilisée pour déterminer sept modèles de prédiction du sexe, en fonction du nombre et du type de canines exploitables. La comparaison des aires sous la courbe ROC a mis en évidence une plus grande performance du modèle utilisant les volumes des 4 canines. La méthode des moindres carrés pondérés a été utilisée pour déterminer les équations d’estimation de l’âge pour les sept mêmes modèles. Une plus grande performance du modèle utilisant les volumes des 2 canines maxillaires a été mise en évidence. Toutes ces régressions ont été testées sur l’échantillon d’application pour procéder à leur validation externe.Il s’avère que dans un contexte scientifique historique où les canines mandibulaires constituaient l’outil dentaire de référence dans la diagnose sexuelle, la modélisation tridimensionnelle souligne l’intérêt potentiel de leurs homologues maxillaires. Par ailleurs, il semblerait que l’évaluation de la réduction pulpaire physiologique, imputable à l’apposition naturelle de dentine secondaire sur les canines uniquement, soit un critère performant dans la détermination de l’âge.A défaut d’être parfaits, les modèles proposés à l’issue cette étude permettent donc toutefois de disposer d’éléments fiables, qui ont toute leur place dans l’indispensable faisceau de preuves, nécessaire à la détermination de l’âge et du sexe dans le cadre d’une identification estimative
The bone methods of sexual diagnosis give excellent results, with rates of good predictions over 90%. Nonetheless, bones are not always available and, when they are, according to the causes of death and/or storage conditions of the body, they may have been severely degraded. To be able to determine the sex of an individual in these situations, dental techniques of sexual diagnosis are needed.In contrast to sex determination, the problem of age estimation has been the topic of many studies and so many different techniques, evidence of failure of all these methods, which the literature did not fail to highlight.The first aim of this work was to propose a simple and accurate dental technique for determining sex, in order to resolve this anthropological issue, reliably in the absence of other elements of the skeleton.The second was to develop a method for estimating the age of easy and fast implémentation, neither requiring a heavy technical support nor damage to material, for an application as well in forensics as in anthropology.The training sample consisted of 210 subjects’ CT-scans, each with four canines healthy. The validation sample was composed of 55 CT-scans, each with at least one healthy canine. Pulp and total volumes of each tooth were modeled and calculated using the software Mimics . A binary logistic regression was used to determine seven prediction models of sex, according to the number and type of canine available in practice. The comparison of the areas under the ROC curve showed a greater performance of the model using the volumes of the four canines. The weighted least squares method was used to determine the equations for estimating the age for the same seven models. Greater performance of the model using the volumes of maxillary canines has been demonstrated. All these regressions were tested on the validation sample to perform their external validation.It turns out that in a scientific context where historical mandibular canines were the reference tool in the sex diagnosis, three-dimensional modeling emphasizes the potential value of maxillary counterparts. Moreover, it appears that the evaluation of the physiological pulp reduction, due to the natural apposition of secondary dentine on canines only, is a performance criterion in determining age.The models proposed in this study can therefore have reliable evidence, which all have all their place in the necessary body of evidence for determining age and sex, in estimating identification

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20

Hurtig, Juliet K. "Parameter set estimation for nonlinear systems /". The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488191124571832.

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21

Gal, Avner. "Passive range estimation using over sea multipath". Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23344.

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This thesis suggests an unconventional, unique method for passive range and height estimation of a cruising missile, or other microwave transmitter. Based on multipath propagation, the method uses 5 receiving antennas in a ladder configuration. Ratios of received signal powers are compared with values from lookup tables to determine the correct location of the transmitter. Computer simulation results are presented, to verify the suggested method. (rh)

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22

Cheung, Man-Fung. "On optimal algorithms for parameter set estimation". The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1302628544.

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23

Watkins, John. "Parameter Set Estimation of Time Varying Systems /". The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487929230739866.

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24

Le, Vu tuan hieu. "Robust predictive control by zonotopic set-membership estimation". Thesis, Supélec, 2012. http://www.theses.fr/2012SUPL0016/document.

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L’objectif de cette thèse est d’apporter des réponses à deux problèmes importants dans le domaine de l’automatique : l'estimation d'état et la commande prédictive robuste sous contraintes pour des systèmes incertains, en se basant sur des méthodes ensemblistes, plus précisément liées aux ensembles zonotopiques. Les incertitudes agissant sur le système sont modélisées de façon déterministe, elles sont donc inconnues mais bornées par des ensembles connus.Dans ce contexte, la première partie de la thèse développe une méthode d’estimation afin d’élaborer à chaque instant un ensemble zonotopique contenant l’état du système malgré la présence de perturbations, de bruits de mesure et d’incertitudes paramétriques définies par intervalle. Cette méthode est fondée sur la minimisation du P-rayon d’un zonotope, critère original permettant de caractériser la taille de l’ensemble zonotopique et réalisant un bon compromis entre la complexité et la précision de l’estimation. Cette approche est tout d’abord développée pour les systèmes mono-sortie, puis étendue au cas des systèmes multi-sorties, dans un premier temps par des extensions directes de la solution mono-sortie (le système multi-sorties est considéré comme plusieurs systèmes mono-sortie). Une autre solution est ensuite proposée, qui conduit à résoudre un problème d’optimisation de type Inégalités Matricielles Polynomiales en utilisant une méthode de relaxation. Les approches précédentes n’étant que des extensions de la solution à une seule sortie, et malgré leurs bons résultats obtenus en simulation, une démarche originale, dédiée aux systèmes multi-sorties, fondée sur l’intersection entre un polytope et un zonotope, est finalement développée et validée.La deuxième partie de la thèse aborde la problématique de la commande robuste par retour de sortie pour des systèmes incertains. La commande prédictive est retenue du fait de son utilisation dans de nombreux domaines, de sa facilité de mise en œuvre et de sa capacité à traiter des contraintes. Parmi les démarches issues de la littérature, l’implantation de techniques robustes fondées sur des tubes de trajectoire est développée plus spécifiquement. Le recours à un observateur ensembliste à base de zonotopes permet d’améliorer la qualité de l’estimation, ainsi que la performance de la commande, dans le cas de systèmes soumis à des perturbations et des bruits de mesure inconnus, mais bornés.Dans une dernière partie, cette combinaison de l’estimation ensembliste et de la commande prédictive robuste est testée en simulation sur un système de suspension magnétique. Les résultats de simulation traduisent un comportement tout à fait satisfaisant validant les structures théoriques élaborées
The aim of this thesis is answering to two significant problems in the field of automatic control: the state estimation and the robust model predictive control for uncertain systems in the presence of input and state constraints, based on the set-membership approach, more precisely related to zonotopic sets. Uncertainties acting on the system are modeled via the deterministic approach, and thus they are unknown but bounded by a known set.In this context, the first part of the thesis proposes an estimation method to compute a zonotope containing the real states of the system, which are consistent with the disturbances, the measurement noise and the interval parametric uncertainties. This method is based on the minimization of the P-radius of a zonotope, which is an original criterion to characterize the size of the zonotope, in order to obtain a good trade-off between the complexity and the precision of the estimation. This approach is first developed for single-output systems, and then extended to the case of multi-output systems. The first solution for multi-output systems is a direct extension of the solution for single-output systems (the multi-output system being considered as several single-output systems). Another solution is then proposed, leading to solve a Polynomial Matrix Inequality optimization problem using a relaxation technique. Due to the fact that the previous approaches are just extensions of the solution for a single-output system, and despite their good performance results obtained in simulation, a novel approach dedicated to multi-output systems based on the intersection of a polytope and a zonotope is finally developed and validated.The second part of the thesis deals with the problem of robust output feedback control for uncertain systems. Model predictive control is chosen due to its use in many areas, its ability to deal with constraints and uncertainties. Among the approaches from the literature, the implementation of robust predictive techniques based on tubes of trajectories is developed. The use of a zonotopic set-membership estimation improves the quality of the estimation, as well as the performance of the control, for systems subject to unknown, but bounded disturbances and measurement noise.In the last part, the combination of zonotopic set-membership estimation and robust model predictive control is tested in simulation on a magnetic levitation system. The simulation results reflect a satisfactory behavior validating the developed theoretical techniques

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25

Iaria, Alessandro. "Essays on choice set heterogeneity in demand estimation". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/62609/.

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The estimation of demand systems is a key activity in empirical economics. The most prominent use of demand estimates relates to the computation of social welfare changes due to modifications in the economic environment. Examples include the introduction of a new tax (Griffith et al. 2010), a change in the regulation of an industry (Crawford & Yurukoglu, 2011), the introduction of a new product (Petrin, 2002), mergers between companies (Nevo, 2000, 2001), the legalization of soft drugs (Jacobi & Sovinsky, 2012). Any sort of welfare exercise, essential for policy making, would require—ideally—perfect knowledge of the economy; in particular individuals’ preferences. In practice, individuals’ preferences cannot be directly observed and have to be estimated. Economic policies based on biased demand estimates may prove rather ineffective or, even worse, counterproductive. In the practice of demand estimation, the empirical literature has prevalently favoured the use of discrete choice models. An individual is represented by a preference relation and, under the assumption of preference maximization, chooses one alternative among a finite collection of them, the choice set. It has been commonly assumed choice set homogeneity among individuals: that is, each decision-maker faces the same set of alternatives. This is a strong assumption that is likely violated in many settings: different individuals involved in apparently similar choice situations do face heterogeneous choice sets. Unfortunately, the very presence of choice set heterogeneity raises new challenges on the way of consistent estimation of consumers’ preferences, i.e., meaningful welfare analyses.

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26

Neto, Fernando Ciriaco Dias. "Otimização multidimensional baseada em heurísticas aplicada aos sistemas de comunicação sem fio". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-16112012-142056/.

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Esse trabalho de investigação visa a realização de uma análise sistemática, integrada e iterativa da utilização de algoritmos heurísticos aplicados aos problemas de estimativa de parâmetros e detecção multiusuário, sob o ponto de vista do compromisso desempenho × complexidade. O sistema considera topologias do tipo CDMA com exploração de diversidade multidimensional, ou seja, que utilizam uma ou mais técnicas de diversidade, considerando a diversidade de código, tempo, frequência e espaço, entre outras, sujeitos a desvanecimentos multipercurso. A solução integrada para os problemas de estimativa de parâmetros e detecção multiusuário consiste no uso recorrente de técnicas heurísticas. Além disso, estabelece-se uma análise comparada e sistêmica de convergência e de complexidade computacional da técnica de detecção proposta com alguns outros métodos, heurísticos ou determinísticos, relatados na literatura, considerando como métrica de desempenho o número de operações computacionais que cada estratégia requer para a detecção simultânea da informação de todos os usuários ativos no sistema. Por fim, e mais importante, considera-se como a principal contribuição deste trabalho a sistematização da utilização dos algoritmos heurísticos no processo de otimização dos problemas já citados, caracterização de limiares de desempenho e análise de complexidade destas técnicas, trazendo à comunidade científica parâmetros suficientes que devem ser respeitados na configuração dos algoritmos para garantia de resultados satisfatórios quando da utilização destes métodos em problemas de detecção multiusuário com diversidade multidimensional e estimativa de parâmetros.
This work will perform a systematic, integrated and iterative research of heuristic algorithms applied to parameter estimation and multiuser detection problems, considering the performance × complexity tradeoff. The CDMA systems with multidimensional diversity exploitation, i.e., with one or more diversity techniques, code diversity, frequency, time and space, among other, in multipath fading channel scenarios are considered. The integrated solution for parameter estimation and multiuser detection problem uses heuristic techniques in recurrent form. In addition, we intend to establish a systemic and comparative analysis of convergence and computational complexity of the proposal detection technique with some other methods, heuristic or deterministic, reported in the literature, considering the number of computational operations that each strategy requires for simultaneous detection from all active users as a performance metrics. Finally, and most importantly, this work systematizes the heuristic algorithms approach in the optimization problems process already mentioned, considering the thresholds for performance and complexity of these techniques, bringing the scientific community enough configuration parameters that must be respected in the setup algorithms step to guarantee satisfactory results when using these methods to multiuser detection with multidimensional diversity and parameter estimation problems.

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27

Kergadallan, Xavier. "Estimation des niveaux marins extrêmes avec et sans l’action des vagues le long du littoral métropolitain". Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1102/document.

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Pour caractériser le risque de submersion marine, il est très important d'avoir une connaissance précise des lois de distribution des niveaux d'eau marins, et plus particulièrement des niveaux d'eau extrêmes. En effet ce sont eux qui sont à l'origine des conséquences les plus dramatiques. Le programme de recherche mené au cours de cette thèse a été financé par le Ministère de l'Écologie, du Développement Durable et de l'Énergie. L'objectif final est de fournir des valeurs de référence de niveau d'eau marin le long des côtes françaises, par le biais d'une méthode d'analyse statistique des extrêmes. Ces niveaux comprennent les trois composantes suivantes : la marée, la surcote météorologique et le wave set-up. Le principe de base utilisé est le suivant : une analyse statistique est effectuée aux ports où la donnée marégraphique est disponible, puis le résultat est interpolé entre les ports. Différentes approches sont testées. Les points suivants sont en particulier étudiés :- la dépendance marée surcote, avec deux différents types de dépendance, une dépendance temporelle et une dépendance en amplitude ;- la méthode d'interpolation, avec la comparaison d'une analyse site-par-site (ASS) avec une analyse régionale (RFA), et celle d'interpolations 1D et 2D ;- l'estimation du wave set-up, basée sur l'état de l'art des formules paramétriques ;- la dépendance surcote vagues, avec des lois bi-variées de valeurs extrêmes. Le résultat final se présente sous la forme de deux profils de niveau d'eau de période de retour 100 ans : le premier sans l'action des vagues (marée et surcote météorologique) et le deuxième avec l'action des vagues. Les valeurs les plus élevées sont atteintes, pour le littoral de la Mer du Nord, la Manche et l'Atlantique, en Baie du Mont-Saint-Michel (à cause des conditions de marée), et pour le littoral méditerranéen au niveau de Marseille. L'analyse montre que la modélisation de la dépendance temporelle marée surcote n'influe pas significativement sur les estimations des valeurs extrêmes. Par contre la modélisation de la dépendance en amplitude donne des résultats intéressants pour certains ports. En comparaison avec l'ASS, la RFA tend à lisser les résultats. Les estimations issues de la RFA sont supérieures pour le littoral méditerranéen, et équivalentes pour le littoral de Mer du Nord, Manche et Atlantique. La RFA serait recommandée pour l'estimation des niveaux de retour en dehors du domaine de validité de l'ASS.À cause du petit nombre de sites d'observation, il est préféré une interpolation 1D le long du trait de côte lissé. Le wave set-up est calculé par la formule de Dean et Walton [2009].La dépendance surcote vagues est moyenne le long du littoral méditerranéen. Le facteur de dépendance montre des variations plus importantes le long du littoral de Mer du Nord, Manche et Atlantique, avec un maximum observé en Baie de Seine et des minima en Baie de Mont-Saint-Michel et au niveau de Calais. Des suggestions sont faites pour améliorer les méthodologies développées et appliquées dans le cadre d'un futur travail
Accurate knowledge of the statistical distribution of extreme sea levels is of the utmost importance for the characterization of flood risks in coastal areas, with a particular interest devoted to extreme water levels because they may induce the most dramatic consequences. Research was funded by the French Ministry of Ecology, Sustainable Development and Energy to identify the risk of flooding from the sea in France. The aim is to provide values on design levels along the French coasts by a statistical method of extreme value analysis. These levels must include the effect of the three following components: tide, meteorological surge and wave set-up. The principle is as follows: an analysis is carried out at the harbours, where seal level observations are available, then the result is interpolated between the harbours. Different approaches are tested. In particularly, the following specific items are studied:- the tide surge dependence, with two different types of dependence: a temporal dependence and an amplitude dependence;- the interpolation method: with the comparison of a site-by-site analysis (SSA) with a Regional Frequency Analysis (RFA), and a 1-D with a 2-D interpolation;- the estimation of the wave set-up, based on the state of art of parametric formula;- the surge wave dependence, with the bivariate laws of extreme values. The final result is two profiles of the 100-year water level: one for the still water level (tide and meteorological surge), and the other for the sea level with the wave set-up. The highest sea levels are located, for the English Channel and Atlantic coasts at the Saint-Michel-bay (because of the tide), and for the Mediterranean coast around Marseille. The analysis shows that the temporal tide surge dependence has no effect on the estimation of the sea level extreme values. In contrast, the model of the amplitude tide surge dependence shows some interesting results for few harbours. In comparison with the SSA, the RFA tends to smooth the result. RFA estimates are higher along the Mediterranean coast, and similarly along the English Channel and Atlantic coasts. RFA would be recommended for estimating return levels out of the SSA validity domain. Because of the small number of observation sites, a 1-D interpolation, along a smoothed coastline, is preferred. The wave set-up is calculated with the formula of Dean and Walton [2009].The surge wave dependence is medium along the Mediterranean coast. Variations of the dependence factor are more important along the English Channel and the Atlantic coasts, with a maximum at the bay of the Seine and some minima at the bay of Saint-Michel and Calais. Some ideas are provided to perform the methodology for further work

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28

Mauroy, Gilles Patrick. "Multiple target tracking using neural networks and set estimation". Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/13748.

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29

Xiong, Jun. "Set-membership state estimation and application on fault detection". Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2013. http://tel.archives-ouvertes.fr/tel-01068054.

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La modélisation des systèmes dynamiques requiert la prise en compte d'incertitudes liées à l'existence inévitable de bruits (bruits de mesure, bruits sur la dynamique), à la méconnaissance de certains phénomènes perturbateurs mais également aux incertitudes sur la valeur des paramètres (spécification de tolérances, phénomène de vieillissement). Alors que certaines de ces incertitudes se prêtent bien à une modélisation de type statistique comme par exemple les bruits de mesure, d'autres se caractérisent mieux par des bornes, sans autre attribut. Dans ce travail de thèse, motivés par les observations ci-dessus, nous traitons le problème de l'intégration d'incertitudes statistiques et à erreurs bornées pour les systèmes linéaires à temps discret. Partant du filtre de Kalman Intervalle (noté IKF) développé dans [Chen 1997], nous proposons des améliorations significatives basées sur des techniques récentes de propagation de contraintes et d'inversion ensembliste qui, contrairement aux mécanismes mis en jeu par l'IKF, permettent d'obtenir un résultat garanti tout en contrôlant le pessimisme de l'analyse par intervalles. Cet algorithme est noté iIKF. Le filtre iIKF a la même structure récursive que le filtre de Kalman classique et délivre un encadrement de tous les estimés optimaux et des matrices de covariance possibles. L'algorithme IKF précédent évite quant à lui le problème de l'inversion des matrices intervalles, ce qui lui vaut de perdre des solutions possibles. Pour l'iIKF, nous proposons une méthode originale garantie pour l'inversion des matrices intervalle qui couple l'algorithme SIVIA (Set Inversion via Interval Analysis) et un ensemble de problèmes de propagation de contraintes. Par ailleurs, plusieurs mécanismes basés sur la propagation de contraintes sont également mis en oeuvre pour limiter l'effet de surestimation due à la propagation d'intervalles dans la structure récursive du filtre. Un algorithme de détection de défauts basé sur iIKF est proposé en mettant en oeuvre une stratégie de boucle semi-fermée qui permet de ne pas réalimenter le filtre avec des mesures corrompues par le défaut dès que celui-ci est détecté. A travers différents exemples, les avantages du filtre iIKF sont exposés et l'efficacité de l'algorithme de détection de défauts est démontré.

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30

Menzel, Konrad Ph D. Massachusetts Institute of Technology. "Essays on set estimation and inference with moment inequalities". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54638.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 141-145).
This thesis explores power and consistency of estimation and inference procedures with moment inequalities, and applications of the moment inequality framework to estimation of frontiers in finance. In the first chapter, I consider estimation of the identified set and inference on a partially identified parameter when the number of moment inequalities is large relative to sample size. Many applications in the recent literature on set estimation have this feature. Examples discussed in this paper include set-identified instrumental variables models, inference under conditional moment inequalities, and dynamic games. I show that GMM-type test statistics will often be poorly centered when the number of moment inequalities is large. My results establish consistency of the set estimator based on a Wald-type criterion, and I give conditions for uniformly valid inference under many weak moment asymptotics for both plug-in and subsampling procedures. The second chapter evaluates the performance of an Anderson-Rubin (AR) type test for a finite number of moment inequalities, and propose a modified Lagrange Multiplier (LM) and a conditional minimum distance (CMD) statistic. The paper outlines a procedure to construct asymptotically valid critical values for both procedures. All three tests are robust, to weak identification, however in most settings, conservative inference using the LM statistic seems to have greater power against local alternatives than the AR-type test. Furthermore, confidence regions based on the LM statistic will remain non-empty if the model is misspecified.
(cont.) Finally, the third chapter, which is co-authored with Victor Chernozhukov and Emre Kocatulum, presents various set inference problems as they appear in finance and proposes practical and powerful inferential tools. Our tools will be applicable to any problem where the set of interest solves a system of smooth estimable inequalities, though we particularly focus on the following two problems: the admissible mean-variance sets of stochastic discount factors and the admissible mean-variance sets of asset portfolios. We propose to make inference on such sets using weighted likelihood-ratio and Wald type statistics, building upon and substantially enriching the available methods for inference on sets.
by Konrad Menzel.
Ph.D.

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31

Miller, James Henry 1957. "Estimation of sea surface wave spectra using acoustic tomography". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/44595.

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Thesis (Sc. D.)--Joint Program in Oceanographic Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 1987.
Bibliography: p. 164-171.
Vita.
by James Henry Miller.
Sc.D.

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32

Moreira, Rafael Barbosa. "Analise de tecnicas de localização em redes de sensores sem fio". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259712.

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Orientador: Paulo Cardieri
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Nesta dissertação, o problema da localização em redes de sensores sem fio é investigado. É apresentada uma análise de desempenho de técnicas de localização por meio de simulação e por meio da avaliação do limite de Cramér-Rao para o erro de localização. Em ambas as formas de análise foram avaliados efeitos de diversos fatores no desempenho, relacionados à topologia da rede e ao ambiente de propagação . Na análise por meio de simulação, foram consideradas as técnicas de localização baseadas em observações de potência do sinal recebido, enquanto que na análise usando o limite de Cramér-Rao, foram analisadas também as técnicas baseadas no tempo de chegada e no ângulo de chegada do sinal recebido. Este trabalho também avaliou os efeitos da polarização das estimativas de distâncias (usadas no processo de localização) no limite inferior de Cramér-Rao. Esta polarização é geralmente desprezada na literatura, o que pode levar a imprecisões no cálculo do limite de Cramér-Rao, em certas condições de propagação. Uma nova expressão para este limite foi derivada para um caso simples de estimador, considerando agora a polarização. Tomando como base o desenvolvimento desta nova expressão, foi derivada também uma nova expressão para o limite inferior de Cramér-Rao considerando os efeitos do desvanecimento lognormal e do desvanecimento Nakagami do canal de propagação
Abstract: This dissertation investigates on the localization problem in wireless sensor networks. A performance analysis of localization techniques through simulations and the Cramér-Rao lower bound is presented. The effects of several parameters on the localization performance are investigated, including network topology and propagation environment. The simulation analysis considered localization techniques based on received signal strength observations, while the Cramér-Rao analysis considered also techniques based on the time of arrival and angle of arrival of the received signal. This work also investigated how the Cramér-Rao limit is affected by the observation bias in localization techniques based on the received signal strength. This bias is usually neglected in the literature, what may lead to imprecisions on the Cramér-Rao limit computation under certain propagation conditions. A new expression for this limit was derived for a simple estimator case, now considering the bias. With the development of this new expression, it was also derived a new expression for the Cramér-Rao lower bound considering the effects of lognormal fading and Nakagami fading on the propagation channel
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica

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33

Fenty, Ian Gouverneur. "State estimation of the Labrador Sea with a coupled sea ice-ocean adjoint model". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59575.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 262-277).
Sea ice (SI) and ocean variability in marginal polar and subpolar seas are closely coupled. SI variability in the Labrador Sea is of climatic interest because of its relationship to deep convection/mode water formation, carbon sequestration, and Northern Hemisphere atmospheric patterns. Historically, quantifying the link between the region's observed SI and oceanic variability has been limited due to in situ observation paucity and technical challenges associated with synthesizing ocean and SI observations with a three-dimensional time-evolving dynamically consistent numerical model. To elaborate upon the relationship between SI and ocean variability, a one year (1996- 1997) state estimate of the ocean and sea ice state in Labrador Sea and Baffin Bay is constructed and analyzed. The estimate is a synthesis of a regional coupled 32 km ocean and sea ice model with a suite of contemporary in situ and satellite hydrographic and SI data. The synthesis of SI data is made possible with the (novel) adjoint of a thermodynamic SI model. Model and data are made consistent, in a least-squares sense, by iteratively adjusting several control variables, such as ocean initial and lateral open boundary conditions and the atmospheric state, to minimize an uncertainty-weighted model-data misfit cost function. It is shown that the SI pack attains a state of quasi-equilibrium in mid-March during which net SI growth/melt approaches zero; newly-formed SI diverges from coastal areas and converges, via wind/ocean forcing, in the marginal ice zone (MIZ). It is further shown that SI converging in the MIZ is primarily ablated by turbulent ocean-SI enthalpy fluxes. The primary source of energy required for sustained MIZ ice ablation is revealed to be the sensible heat reservoir of the subtropical-origin subsurface waters. Enthalpy from the heat reservoir is entrained into the mixed layer via buoyancy loss-driven convective deepening and brought to the SI via vertical mixing. An analysis of ocean surface buoyancy fluxes reveals a critical role of low-salinity upper ocean anomalies for the advancement of SI seaward of the Arctic Water/Irminger Water thermohaline front. Anomalous low-salinity waters slow the rate of buoyancy loss-driven mixed layer deepening, shielding an advancing SI pack from the subsurface heat reservoir, and are conducive to a positive surface stratification enhancement feedback from SI meltwater release, both of which extend SI lifetimes. Preliminary analysis of two additional one-year state estimates (1992-1993, 2003-2004) suggests that interannual hydrographic variability provides a first-order explanation for SI maximum extent anomalies. Additional research on the mechanisms controlling the origin and distribution of upper ocean salinity anomalies is required to further understand observed SI variability in the northwest North Atlantic.
by Ian Gouverneur Fenty.
Ph.D.

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34

Arendt, Christopher D. "Adaptive Pareto Set Estimation for Stochastic Mixed Variable Design Problems". Ft. Belvoir : Defense Technical Information Center, 2009. http://handle.dtic.mil/100.2/ADA499860.

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Codd, Casey L. "Nonlinear Structural Equation Models: Estimation and Applications". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1301409131.

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Ramos, Alex Lacerda. "Sensor data security estimator : um framework para estimativa do nível de segurança dos dados de redes de sensores sem fio". Universidade de Fortaleza, 2013. http://dspace.unifor.br/handle/tede/91396.

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Wireless Sensor Networks (WSN) are becoming increasingly popular in civilian and military applications, such as monitoring, disaster recovery, control, automation and many others. Due to this dissemination of WSN and lack of computational resources of sensors, these networks have become target of all kinds of attacks from adversaries interested in compromising their operation. Thus, in recent years, many security mechanisms have been proposed to minimize the impact of attacks in sensor networks and make users of these networks to have access to reliable data. However, it is possible that adversaries are able to perform attacks capable of circumventing the security mechanisms installed in a WSN, making that the users of these networks receive corrupted data, even though they have the impression that they are using reliable data. Thus, it is necessary a mechanism able to quantify the security level of the sensor data and inform it to WSN users so that they can be aware of the reliability of these data and be able to make educated decisions about their use. However, existing works to quantify security in WSN are still not able to meet all the criteria necessary to estimate the security level of the sensor data. Hence, this work presents the Sensor Data Security Estimator (SDSE), a framework able to estimate the security level of data from wireless sensor networks using security metrics obtained from security mechanisms installed in the network. The security metrics defined by the SDSE can also be used to help professionals to make decisions about how to choose between alternative security architectures and evaluate different security mechanisms. The metrics and security level estimated by the SDSE are rigorously validated through simulations that show the accuracy of the proposed framework. The comparisons with other existing works show that the results obtained by the SDSE are quite promising. Keywords: Wireless Sensor Networks, Security Level, Security Metrics.
As Redes de Sensores sem Fio (RSSF) estão se tornando cada vez mais populares em aplicações militares e civis, tais como monitoramento, recuperação de desastres, controle, automação e muitas outras. Devido a essa difusão das RSSF e a escassez de recursos computacionais dos sensores, essas redes se tornaram alvo dos mais variados tipos de ataques de adversários interessados em comprometer seu funcionamento. Com isso, nos últimos anos, inúmeros mecanismos de segurança vêm sendo propostos para minimizar o impacto de ataques nas redes de sensores e fazer com que os usuários destas redes tenham acesso a dados confiáveis. Entretanto, é possível que adversários consigam realizar ataques capazes de burlar os mecanismos de segurança instalados em uma RSSF, fazendo com que os usuários dessas redes recebam dados corrompidos, embora tenham a impressão de que estão utilizando dados confiáveis. Desse modo, faz-se necessário um mecanismo capaz de quantificar o nível de segurança dos dados dos sensores e informá-lo aos usuários das RSSF, para que estes tenham conhecimento da confiabilidade desses dados e possam tomar decisões informadas sobre sua utilização. Contudo, os trabalhos existentes para quantificar segurança em RSSF ainda não são capazes de atender a todos os critérios necessários para se estimar o nível de segurança dos dados dos sensores. Diante disso, este trabalho apresenta o Sensor Data Security Estimator (SDSE), um framework capaz de estimar o nível de segurança dos dados de uma rede de sensores sem fio a partir de métricas de segurança obtidas por meio dos mecanismos de segurança instalados na rede. As métricas de segurança definidas pelo SDSE também podem ser utilizadas para ajudar profissionais a tomar decisões sobre como escolher entre arquiteturas de segurança alternativas e avaliar diferentes mecanismos de segurança. As métricas e o nível de segurança estimados pelo SDSE são rigorosamente validados por meio de simulações que mostram a acurácia do framework proposto. As comparações realizadas com outros trabalhos existentes apontam que os resultados obtidos pelo SDSE são bastante promissores. Palavras-chave: Redes de Sensores sem Fio, Nível de Segurança, Métricas de Segurança.

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37

Mao, Hongwei. "Estimating labour productivity using fuzzy set theory". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0019/MQ47065.pdf.

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38

Oliveira, Rogerio Nogueira de. "Estimativa do sexo atraves de mensurações mandibulares". [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288744.

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Orientador: Roberto Jose Gonçalves
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-07-21T03:57:47Z (GMT). No. of bitstreams: 1 Oliveira_RogerioNogueirade_M.pdf: 2720920 bytes, checksum: 0fbf62c465a59749b011d8cd55e204a4 (MD5) Previous issue date: 1996
Resumo: o presente trabalho teve como objetivo desenvolver metodologias para possibilitar a determinação do sexo através de mensurações mandibulares, verificando-se a aplicabilidade da metodologia encontrada na bibliografia, em padrões nacionais, como meio complementar no processo de identificação. Foram estudadas 175 mandíbulas, de indivíduos adultos (acima de 20 anos) de procedência e sexo conhecidos, independentemente da raça. O estudo baseou-se em quatro medidas a saber: a altura do ramo mandibular, o comprimento total da mandíbula, a distância bigoníaca e a largura mínima do ramo mandibular. Pela análise do dados, 'verificou-se que os resultados não coincidiam com os descritos na bibliografia, sendo que foi necessário o ajustamento do valor crítico limite entre os sexos. Além disso, estabeleceu-se, através de análises estatísticas, duas medidas que mostraram-se mais fidedignas em relação ao dimorfismo sexual, a saber: altura do ramo mandibular e distância bigoníaca. Foram também estabelecidas novas fórmulas, através da regressão logística e da análise discriminante, utilizando-se somente as duas medidas selecionadas. Foi ainda elaborado um # software" (Sexmandi), para a execução rápida, segura e confiável dos cálculos para determinação do sexo, por mensurações mandibulares, com obtenção de um escore de probabilidade numa taxa de acerto média de 77,7%
Abstract: The purpose of this work is to study gender determination through mandibular mensurations. It also intends to verify the applicability of the methodology found in the bibliography in national standards as a supplementary way in the identification processo With this purpose we have studied 175 adult mandibles (above twenty) whose gender and origin were known, independent of their race. The study was based on four mensurations, namely: the height of the branch, the totallenth of the mandible, the bigonial distance and finally, the minimal width of the branch. The analysis of the dáta has shown that the results did not coincide with the ones found in the pertenent litrature. After having made the adjustment of the critica! value we have two similar results. During our research we concluded that the branchand and the bigonia! width are statistically more significant in relationto the sexual dimorphism and so we stablished new formulae, using only these two mensures. This study led to the development of a software (Sexmandi) for quick, safe and reliable performance of the calculation to determine sex through mandibular mensuratians with a rate af accuracy af 77,7% and the presentatian af a prabability scare
Mestrado
Odontologia Legal e Deontologia
Mestre em Ciências

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39

Aji, Sudarshan Mandayam. "Estimating Reachability Set Sizes in Dynamic Graphs". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49262.

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Graphs are a commonly used abstraction for diverse kinds of interactions, e.g., on Twitter and Facebook. Different kinds of topological properties of such graphs are computed for gaining insights into their structure. Computing properties of large real networks is computationally very challenging. Further, most real world networks are dynamic, i.e., they change over time. Therefore there is a need for efficient dynamic algorithms that offer good space-time trade-offs. In this thesis we study the problem of computing the reachability set size of a vertex, which is a fundamental problem, with applications in databases and social networks. We develop the first Giraph based algorithms for different dynamic versions of these problems, which scale to graphs with millions of edges.
Master of Science

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40

Sroka, Christopher J. "Extending Ranked Set Sampling to Survey Methodology". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218543909.

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41

Nguyen, Hoang Van. "Estimation d'attitude et diagnostic d'une centrale d'attitude par des outils ensemblistes". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00585525.

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L'estimation de l'attitude (ou orientation) est un problème récurrent de nombreuses applications allant de la robotique aérienne ou sous-marine en passant par des applications médicales (surveillance de patients, réhabilitation), mais aussi jeux vidéo, etc. L'objectif de cette thèse est d'évaluer l'apport des approches ensemblistes dans le cadre de l'estimation de l'attitude à partir de données issues de triaxes accéléromètres (A), magnétomètres (M) et gyromètres (G). Dans un premier temps, on s'intéresse aux mouvements "quasi-statiques" et l'estimation de l'attitude est réalisée à partir de mesures AM. On aborde ensuite le cas des mouvements dynamiques, en considérant l'ensemble des mesures AGM. Le problème du choix de la paramétrisation de l'attitude a été abordé et on a comparé les résultats obtenus et le temps calcul pour des modélisations avec les angles de Cardan et le quaternion unitaire. Les algorithmes développés ont été validés en simulation et avec des données réelles. Les résultats ont été comparés avec ceux fournis par des algorithmes de l'état de l'art, par exemple SIVIA. La deuxième partie du manuscrit est consacrée à au diagnostic des capteurs de la centrale inertielle avec des approches ensemblistes. Les algorithmes développés dans la première partie du travail sont adaptés afin de pouvoir détecter et localiser un défaut dans l'ensemble des capteurs considérés.

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42

Snellen, Mirjam. "Sea bottom parameter estimation by inversion of underwater acoustic sonar data". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/65426.

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43

譚玉貞 e Yuk-ching Tam. "Some practical issues in estimation based on a ranked set sample". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31221683.

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Tam, Yuk-ching. "Some practical issues in estimation based on a ranked set sample /". Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20897169.

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45

Lindell, David Brian. "Arctic Sea Ice Classification and Soil Moisture Estimation Using Microwave Sensors". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6153.

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Spaceborne microwave sensors are capable of estimating various properties of many geophysical phenomena, including the age and extent of Arctic sea ice and the relative soil moisture over land. The measurement and classification of such geophysical phenomena are used to refine climate models, localize and predict drought, and better understand the water cycle. Data from the active Ku-band scatterometers, the Quick Scatterometer (QuikSCAT), and the Oceansat-2 Scatterometer (OSCAT), are here used to classify areas of first-year and multiyear Arctic sea ice using a temporally adaptive threshold on reported radar backscatter values. The result is a 15-year data record of daily ice classification images. An additional ice age data record is produced using the C-band Advanced Scatterometer (ASCAT) and the Special Sensor Microwave Imager Sounder (SSMIS) with an alternate classification methodology based on Bayesian decision theory. The ASCAT/SSMIS classification methodology results in a record which is generally consistent with the QuikSCAT and OSCAT classifications, which conclude in 2014. With multiple ASCAT and SSMIS sensors still operational, the ASCAT/SSMIS ice classifications can continue to be produced into the future. In addition to ice classification, ASCAT is used to estimate the relative surface soil moisture at high-resolution (4.45 — 4.45 km per pixel). The soil moisture estimates are obtained using enhanced resolution image reconstruction techniques and an altered version of the Water Retrieval Package (WARP) algorithm. The high-resolution soil moisture estimates are shown to agree well with the existing lower resolution WARP products while also revealing finer details.

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46

Gehly, Steve. "Estimation of geosynchronous space objects using finite set statistics filtering methods". Thesis, University of Colorado at Boulder, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10195335.

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The use of near Earth space has increased dramatically in the past few decades, and operational satellites are an integral part of modern society. The increased presence in space has led to an increase in the amount of orbital debris, which poses a growing threat to current and future space missions. Characterization of the debris environment is crucial to our continued use of high value orbit regimes such as the geosynchronous (GEO) belt. Objects in GEO pose unique challenges, by virtue of being densely spaced and tracked by a limited number of sensors in short observation windows. This research examines the use of a new class of multitarget filters to approach the problem of orbit determination for the large number of objects present. The filters make use of a recently developed mathematical toolbox derived from point process theory known as Finite Set Statistics (FISST). Details of implementing FISST-derived filters are discussed, and a qualitative and quantitative comparison between FISST and traditional multitarget estimators demonstrates the suitability of the new methods for space object estimation. Specific challenges in the areas of sensor allocation and initial orbit determination are addressed in the framework. The sensor allocation scheme makes use of information gain functionals as formulated for FISST to efficiently collect measurements on the full multitarget system. Results from a simulated network of three ground stations tracking a large catalog of geosynchronous objects demonstrate improved performance as compared to simpler, non-information theoretic tasking schemes. Further studies incorporate an initial orbit determination technique to initiate new tracks in the multitarget filter. Together with a sensor allocation scheme designed to search for new targets and maintain knowledge of the existing catalog, the method comprises a solution to the search-detect-track problem. Simulation results for a single sensor case show that the problem can be solved for multiple objects with no a priori information, even in the presence of missed detections and false measurements. Collectively, this research seeks to advance the capabilities of FISST-derived filters for use in the estimation of geosynchronous space objects; additional directions for future research are presented in the conclusion.

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Villanueva, Mario Eduardo. "Set-theoretic methods for analysis estimation and control of nonlinear systems". Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/32528.

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This thesis is concerned with the application of set-theoretical methods to problems in analysis, estimation and control of nonlinear systems. Set-theoretical concepts are often used in the formulation of various problems in science and engineering. One of the key enablers for the successful application of set-theoretical methods is the ability to enclose the image set of nonlinear multivariate systems, which is the focus of the main body of this thesis. Chapter 2 concentrates on bounding the image of factorable, vector-valued functions. To this aim, a framework is developed which enables the analysis of existing set-valued arithmetics---such as interval and polynomial model arithmetics---and the construction of new ones e.g. an ellipsoidal arithmetic for vector-valued nonlinear factorable functions. This framework also allows to study on a unified way the convergence (in the Hausdorff sense) of the enclosures to the exact image as the domain of the function shrinks. Chapters 3 and 4 are concerned with set propagation through dynamic systems (reachability analysis) defined by parametric ordinary differential equations (ODEs). Computing enclosures for the reachable set is not straightforward, since it is the image of a function which is not factorable, but it is defined implicitly by the ODEs. Nevertheless, computational methods for reachability analysis can take advantage the factorable structure of the ODE right-hand side. The focus on Chapter 3 is on discrete-time set propagation, i.e. methods where the integration horizon is discretized into finite steps, and then propagating the enclosure through each of these steps. Classical methods rely on Taylor expansions of the ODE solution and proceed in two phases. First, an a step-size and an a priori enclosure for the reachable set over the current step are determined. Then, the enclosure is tightened at the end of the step. The algorithm presented in this chapter is also based on Taylor expansions of the solution, but the order of the phases is reversed. This construction leads to a natural step-size control mechanism and eliminates the need for tightening the enclosure at the end of the time-step. Furthermore, sufficient conditions are then derived for the algorithm to be locally asymptotically stable in the neighborhood of a locally asymptotically stable periodic orbit or equilibrium point. The key requirement for stability is that the affine-set extensions used in the propagation have quadratic Hausdorff convergence order. On the other hand, Chapter 4 deals with continuous-time set propagation methods. These class of methods rely on the construction of an auxiliary system of ODEs, whose solution is guaranteed to enclose the reachable set of the original ODEs. Here, a unified framework for the construction of continuous time methods is presented. It is based on a generalized differential inequality (GDI), whose solutions describe the support function of time-varying enclosures for the reachable set. This GDI contains as special cases known continuous-time reachability methods, such as differential inequalities and ellipsoidal set propagation techniques. Although the GDI is based on the support function characterization of convex sets, an extension for nonconvex sets is provided using polynomial models with convex remainders. The framework also provides a means for analyzing the Hausdorff convergence properties of continuous-time enclosure methods. A nontrivial extension of the GDI in the form of a min-max differential inequality is also introduced for the characterization of robust forward invariant tubes. This min-max DI provides as a by product a semi-explicit nonlinear feedback control law, which can also be exploited in robust optimal control and tube-based robust model predictive control. Chapter 5 is concerned with the characterization of sets defined implicitly by systems of constraints. These problems are addressed from a set-theoretical perspective, by adopting the use of complete-search based constraint projection methods. The chapter presents a branch-and-prune algorithm which is enhanced by the use of higher order bounding strategies based on polynomial models. The use of optimization-based domain reduction strategies inspired by developments in branch-and-bound algorithms for complete-search global optimization is also studied. We also introduce a CPU time reduction strategy for polynomial models, which allows reusing the computed bounds whenever they have converged. For constraint systems that include undetermined systems of equations a domain reduction strategy in reduced space is presented. This strategy relies on the use of polynomial models in order to characterize the boundary of the set and makes use of state-of-the-art Newton-like methods for the solution of systems of nonlinear implicit algebraic equations. The algorithm is applied to two different problems: guaranteed parameter estimation and guaranteed asymptotic analysis. The methods in this thesis have been implemented in CRONOS (https://bitbucket.org/omega-icl/cronos), a C++ library that builds upon the MC++ library (https://bitbucket.org/omega-icl/mcpp) for bounding factorable functions. These algorithms have also been tested in a variety of case studies drawn from Chemical Engineering and Systems biology.

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Chiang, Chung-Jung. "Applications of the Total Least Squares technique to frequency estimation". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School; Available from the National Technical Information Service, 1992. http://edocs.nps.edu/npspubs/scholarly/theses/1992/Sep/92Sep_Chiang.pdf.

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49

Sugiyama, Masahiro Ph D. Massachusetts Institute of Technology. "Estimating the economic cost of sea-level rise". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38529.

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This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2007.
Includes bibliographical references (p. 74-79).
(cont.) In the case of a classical linear sea-level rise of one meter per century, the use of DIVA generally decreases the protection fraction of the coastline, and results in a smaller protection cost because of high spatial concentration of capital. As in past studies, wetland loss continues to be dominant for most regions, and the total cost does not decline appreciably where wetland loss remains about the same. The total cost for the United States is about $320 billion (in 1995 U.S. dollars), an estimate comparable with other studies. Nevertheless, capital loss and protection cost may not be negligible for developing countries, in light of their small gross domestic product. Using realistic sea-level rise scenarios based on the Integrated Global System Model (IGSM) simulations substantially reduce the cost of sea-level rise for two reasons: a smaller rise of sea level in 2100 and a nonlinear form of the path of sea-level rise. As in many of the past studies, the thesis employs conventional but rather unrealistic assumptions: perfect information about future sea-level rise and neglect of the stochastic nature of storm surges. The author suggests that future work should tackle uncertain and stochastic sea-level rise damages.
To improve the estimate of economic costs of future sea-level rise associated with global climate change, the thesis generalizes the sea-level rise cost function originally proposed by Fankhauser, and applies it to a new database on coastal vulnerability, Dynamic Interactive Vulnerability Assessment (DIVA). With the new cost function, a new estimate of the cost present values over the 21st century is produced. An analytic expression for the generalized sea-level rise cost function is obtained to explore the effect of various spatial distributions of capital and nonlinear sea-level rise scenarios. With its high spatial resolution, DIVA shows that capital is usually highly spatially concentrated along a nation's coastline, and that previous studies, which assumed linear marginal capital loss for lack of this information, probably overestimated the fraction of a nation's coastline to be protected and protection cost. In addition, the new function can treat a sea-level rise that is nonlinear in time. As a nonlinear sea-level rise causes more costs in the future than an equivalent linear sea-level rise scenario, using the new equation with a nonlinear scenario also reduces the estimated damage and protection fraction through discounting of the costs in later periods. Numerical calculations are performed, applying the cost function to DIVA and socio-economic scenarios from the MIT Emissions Prediction and Policy Analysis (EPPA) model.
by Masahiro Sugiyama.
S.M.

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Krummenauer, Rafael. "Sobre modelos e métodos de estimação de direção de chegada de sinais em sistemas digitais de comunicação sem fio". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260619.

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Abstract (sommario):

Orientador: Amauri Lopes
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-19T00:45:48Z (GMT). No. of bitstreams: 1 Krummenauer_Rafael_D.pdf: 3012176 bytes, checksum: 0650db76fe599c68547540bc1a973c9b (MD5) Previous issue date: 2011
Resumo: Nesta tese tratamos do problema de estimação de direção de chegada de sinais digitalmente modulados, especificamente encontrado no enlace reverso de sistemas de comunicação semfiomultiusuário em que a estação rádio-base é composta por um arranjo de antenas, posicionadas de acordo com alguma geometria pré-definida. Os objetivos principais da tese são: esclarecer detalhes normalmente não tratados na descrição dos modelos de dados considerados na literatura existente, em especial, a respeito das condições de enlace e do sistema receptor necessárias para suportar a validade dos modelos empregados; agrupar alguns dos métodos de estimação existentes mais relevantes para o contexto tratado e avaliar suas vantagens e desvantagens; e introduzir o método de estimação desenvolvido nas pesquisas do período de doutorado, o qual representa a contribuição maior da tese em termos de metodologia. A solução proposta é fundamentada no critério da máxima verossimilhança e as análises de desempenho feitas através de simulações numéricas mostram que o estimador fornece resultados com qualidade próxima ao limite definido pelo limitante de Cramér-Rao. Algumas características importantes do método são: i) capacidade de operar com qualquer número de fontes se o número de antenas for maior ou igual a dois e o número de snapshots for suficientemente maior que a cardinalidade do espaço de sinal; ii) a qualidade da estimação não é afetada pela separação angular entre as fontes; e iii) possibilidade de operar com arranjos descalibrados
Abstract: This thesis deals with the problem of estimating the direction of arrival of digitally modulated signals, specifically found in the uplink of multiuser wireless communication systems where the base station uses an antenna array. The main objectives of the thesis are: to clarify some details normally not treated in the description of the data models assumed in the existing literature, specially, on link and receiver conditions that are necessary to validate the employed models; to present some of the most relevant estimation methods to the current context and to evaluate their advantages and disadvantages; and to introduce the estimation method developed in the researches during the doctoral period, which represents the greater contribution of the thesis in terms of metodology. The proposed solution is fundamented in the maximum likelihood criterion and the performance analysis done through numerical simulations show that the estimator yields results with a quality close to that defined by the Cramér-Rao bound. Some important characteristics of the method are: i) capacity to operate with any number of sources if the number of antennas is greater than or equal to two and the number of snapshots is sufficiently greater than the cardinality of the signal space; ii) the estimation quality does not depend on the angle separation between sources; and iii) possibility to operate with uncalibrated arrays
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica

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