Academic literature on the topic 'Consecutive acquisitions'
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Journal articles on the topic "Consecutive acquisitions"
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Clarençon, Frédéric, Stéphanie Lenck, Eimad Shotar, et al. "Four-dimensional digital subtraction angiography for exploration of spinal cord vascular malformations: preliminary experience." Journal of NeuroInterventional Surgery 13, no. 1 (2020): 69–74. http://dx.doi.org/10.1136/neurintsurg-2020-015909.
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BackgroundThe precise understanding of the angioarchitecture of spinal vascular malformations (SVMs) is often difficult to reach with conventional digital subtraction angiography (DSA). The purpose of our study was to evaluate the potential of four-dimensional DSA (4D-DSA) (Siemens Healthcare) in the exploration of SVMs.MethodsWe retrospectively studied all patients who underwent spinal DSA, including 4D-DSA acquisition, from July 2018 to June 2019 at a single institution. All spinal DSA acquisitions were performed under general anesthesia. 4D-DSA acquisitions were acquired with the protocol '12 s DSA Dyna4D Neuro'. 12 mL of iodixanol 320 mg iodine/mL were injected via a 5 F catheter (1 mL/s during the 12 s 4D-DSA acquisition). Inter-rater (three independent reviewers) and intermodality agreements were assessed.ResultsNine consecutive patients (six men, three women, mean age 55.3±19.8 years) with 10 SVMs (spinal dural arteriovenous fistulas n=3, spinal epidural arteriovenous fistulas n=2, spinal pial arteriovenous fistulas n=2, and spinal arteriovenous malformations n=2; one patient had two synchronous pial fistulas) had spinal DSA, including 4D-DSA acquisition. Inter-rater agreement was good and moderate for the venous drainage pattern and the SVM subtype, respectively. In 9 of 10 cases, the quality of the acquisition was graded as good. Satisfactory concordance between 4D-DSA and the selective microcatheterization was observed in 90% of cases for the location of the shunt point.Conclusion4D-DSA acquisition may be helpful for a better understanding of the angioarchitecture of SVMs. Larger series are warranted to confirm these preliminary results.
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Hysmith, Nicholas D., Edward L. Kaplan, P. Patrick Cleary, Dwight R. Johnson, Thomas A. Penfound, and James B. Dale. "Prospective Longitudinal Analysis of Immune Responses in Pediatric Subjects After Pharyngeal Acquisition of Group A Streptococci." Journal of the Pediatric Infectious Diseases Society 6, no. 2 (2017): 187–96. http://dx.doi.org/10.1093/jpids/piw070.
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Abstract Background. Despite the significant burden of disease associated with infection by group A streptococcus (GAS), little is known about the human immune response to GAS antigens after natural infection. Methods. We evaluated 195 serum samples obtained prospectively over a consecutive 24-month period from 41 pediatric subjects who experienced a new pharyngeal GAS acquisition. An enzyme-linked immunoassay was used to determine the kinetics and antigen specificity of antibodies against 13 shared GAS antigens and 18 type-specific M peptides. The majority of the antigens tested are currently being considered as vaccine candidates. Results. Twelve M types of GAS were recovered from 41 subjects who experienced 51 new GAS acquisitions that elicited antibody responses against at least 1 of the 31 antigens tested (immunologically significant new GAS acquisitions). The immune responses to the 13 shared antigens were highly variable. Increases in antibody levels were detected against a mean of 3.5 shared antigens (range, 1–8). Antibody responses to the homologous M peptide were observed in 32 (63%) of the 51 episodes. Seven subjects acquired more than 1 M type of GAS. There were no new immunologically significant acquisitions of an M type against which the subject had preexisting antibodies to the homologous M peptide. Of the subjects with new GAS acquisition, 65% were asymptomatic, yet immune responses were detected against 1 or more GAS antigens. Immune responses to streptolysin O and/or deoxyribonuclease B were observed after 67% of the new GAS acquisitions. Persistently positive (>12 weeks) throat culture results were returned for 20% of the 41 subjects despite immune responses to homologous M peptides and/or shared antigens. Conclusions. The availability of throat culture results, GAS isolates, and serial serum samples collected prospectively over a 2-year period of observation provided a unique opportunity for us to assess the serologic status of pediatric subjects before and after new pharyngeal acquisitions of GAS. With the exception of antibody responses to the homologous M peptides, no clear pattern of immune responses against the remaining GAS antigens was seen. There were no new immunologically significant acquisitions ofemm types of GAS against which the subjects had preexisting elevated levels of antibodies against the homologous M peptide. The observation that 65% of new GAS acquisitions caused no symptoms yet were immunologically significant suggests that the majority of infections are not detected, which would result in missed opportunities for primary prevention of rheumatic fever and rheumatic heart disease with appropriate antimicrobial therapy.
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Molijn, Ramses, Lorenzo Iannini, Paco López Dekker, Paulo Magalhães, and Ramon Hanssen. "Vegetation Characterization through the Use of Precipitation-Affected SAR Signals." Remote Sensing 10, no. 10 (2018): 1647. http://dx.doi.org/10.3390/rs10101647.
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Current space-based SAR offers unique opportunities to classify vegetation types and to monitor vegetation growth due to its frequent acquisitions and its sensitivity to vegetation geometry. However, SAR signals also experience frequent temporal fluctuations caused by precipitation events, complicating the mapping and monitoring of vegetation. In this paper, we show that the influence of a priori known precipitation events on the signals can be used advantageously for the classification of vegetation conditions. For this, we exploit the change in Sentinel-1 backscatter response between consecutive acquisitions under varying wetness conditions, which we show is dependent on the state of vegetation. The performance further improves when a priori information on the soil type is taken into account.
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Anger, J., T. Ehret, C. de Franchis, and G. Facciolo. "FAST AND ACCURATE MULTI-FRAME SUPER-RESOLUTION OF SATELLITE IMAGES." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-1-2020 (August 3, 2020): 57–64. http://dx.doi.org/10.5194/isprs-annals-v-1-2020-57-2020.
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Abstract. Recent constellations of small satellites, such as Planet’s SkySats, offer new acquisition modes where very short videos or bursts of images are acquired instead of a single still image. Compared to sequences of multi-date images, these sequences of consecutive video frames yield a large redundancy of information within the range of seconds. This redundancy enables to increase the spatial resolution using multi-frame super-resolution algorithms. In this paper, we propose a novel super-resolution method based on a high-order spline interpolation model that combines multiple low-resolution frames to produce a high-resolution image. Moreover this method can be implemented efficiently on GPU to process entire images from real satellite acquisitions. Synthetic and real experiments show that the proposed method is able to recover fine details, and measurements of the resulting resolution indicate a gain of 10 cm / pixel with respect to Planet’s SkySat standard imagery products.
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Moller, Delwyn, Scott Hensley, Jeremie Mouginot, et al. "Validation of Glacier Topographic Acquisitions from an Airborne Single-Pass Interferometer." Sensors 19, no. 17 (2019): 3700. http://dx.doi.org/10.3390/s19173700.
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The airborne glacier and ice surface topography interferometer (GLISTIN-A) is a single-pass radar interferometer developed for accurate high-resolution swath mapping of dynamic ice surfaces. We present the first validation results of the operational sensor, collected in 2013 over glaciers in Alaska and followed by more exhaustive collections from Greenland in 2016 and 2017. In Alaska, overlapping flight-tracks were mosaicked to mitigate potential residual trends across-track and the resultant maps are validated with lidar. Furthermore, repeat acquisitions of Columbia Glacier collected with a three day separation indicate excellent stability and repeatability. Commencing 2016, GLISTIN-A has circumnavigated Greenland for 4 consecutive years. Due to flight hour limitations, overlapping swaths were not flown. In 2016, comparison with airborne lidar data finds that residual systematic errors exhibit evenly distributed small slopes (all less than 10 millidegrees) and nadir biases were typically less than 1 m. Similarly 2017 data exhibited up to meter-scale nadir biases and evenly distributed residual slopes with a standard deviation of ~10 millidegrees). All satisfied the science accuracy requirements of the Greenland campaigns (3 m accuracy across an 8 km swath).
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Kang, Daehun, Yul-Wan Sung, and Chang-Ki Kang. "Fast Imaging Technique for fMRI: Consecutive Multishot Echo Planar Imaging Accelerated with GRAPPA Technique." BioMed Research International 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/394213.
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This study was to evaluate the proposed consecutive multishot echo planar imaging (cmsEPI) combined with a parallel imaging technique in terms of signal-to-noise ratio (SNR) and acceleration for a functional imaging study. We developed cmsEPI sequence using both consecutively acquired multishot EPI segments and variable flip angles to minimize the delay between segments and to maximize the SNR, respectively. We also combined cmsEPI with the generalized autocalibrating partially parallel acquisitions (GRAPPA) method. Temporal SNRs were measured at different acceleration factors and number of segments for functional sensitivity evaluation. We also examined the geometric distortions, which inherently occurred in EPI sequence. The practical acceleration factors,R=2orR=3, of the proposed technique improved the temporal SNR by maximally 18% in phantom test and by averagely 8.2% in in vivo experiment, compared to cmsEPI without parallel imaging. The data collection time was decreased in inverse proportion to the acceleration factor as well. The improved temporal SNR resulted in better statistical power when evaluated on the functional response of the brain. In this study, we demonstrated that the combination of cmsEPI with the parallel imaging technique could provide the improved functional sensitivity for functional imaging study, compensating for the lower SNR by cmsEPI.
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Batra, Rahul, Jonathan Edgeworth, Jerome Wulff, and David Harrison. "2471. Review of Methicillin-Resistant Staphylococcus aureus, Clostridium difficile and Acquired Bloodstream Infections Across all United Kingdom Intensive Care Units following Implementation of a Statutory National Infection Control Campaign." Open Forum Infectious Diseases 6, Supplement_2 (2019): S856. http://dx.doi.org/10.1093/ofid/ofz360.2149.
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Abstract Background Methicillin-Resistant Staphylococcus aureus (MRSA) and C. difficile infection have reduced across the UK National Health Service in the last decade following implementation of an infection control campaign. The national impact on hospital-acquired infections in the ICU however has not been comprehensively documented. Methods Data on MRSA, C. difficile, vancomycin-resistant Enterococcus (VRE) and ICU-acquired bloodstream infection (UABSIs) were analyzed from 1,189,142 consecutive patients from 2007 to 2016 recorded prospectively and standardized by highly trained assessors. Initial coverage was 139 ICUs increasing to 275 ICUs representing 100% of general, adult UK ICUs. Results ICU MRSA and C. difficile admissions and acquisitions per 1000 patients decreased between 2007 and 2012 (MRSA admissions 38.8 to 13.1; acquisitions 25.4 to 4.1; C. difficile admissions 10.6 to 4.2; acquisitions 11.1 to 3.5), whereas VRE admissions and acquisitions increased from 1.9 to 5.3 and 1.5 to 5.9, respectively. There were 13,114 UABSIs in 1.8% patients staying >48 hours. UABSIs fell from 7.3 (95% CI 6.9–7.6) to 1.6 (95% CI 1.5–1.7)/1,000 bed-days between 2007 and 2012. Adjusting for patient admission and ICU factors the IRR was 0.21 (95% CI 0.19–0.23, P < 0.001) from 2007 to 2016. Reductions in UABSIs were seen for all main organisms excluding VRE with greatest reductions for MRSA (97%), Pseudomonas aeruginosa (80%), S. aureus (77%) and Candida spp. (71%) but lower reductions for E. coli (54%) and Klebsiella (42%). Conclusion Large decreases in ICU-acquired infections occurred across the UK ICU network between 2007 and 2012 linked with the first few years of the national infection control campaign, but rates have been static since. Further reductions in ICU will likely require a new intervention framework. Disclosures All authors: No reported disclosures.
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Ganeshan, Balaji, Kenneth Miles, Asim Afaq, et al. "Texture Analysis of Fractional Water Content Images Acquired during PET/MRI: Initial Evidence for an Association with Total Lesion Glycolysis, Survival and Gene Mutation Profile in Primary Colorectal Cancer." Cancers 13, no. 11 (2021): 2715. http://dx.doi.org/10.3390/cancers13112715.
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To assess the capability of fractional water content (FWC) texture analysis (TA) to generate biologically relevant information from routine PET/MRI acquisitions for colorectal cancer (CRC) patients. Thirty consecutive primary CRC patients (mean age 63.9, range 42–83 years) prospectively underwent FDG-PET/MRI. FWC tumor parametric images generated from Dixon MR sequences underwent TA using commercially available research software (TexRAD). Data analysis comprised (1) identification of functional imaging correlates for texture features (TF) with low inter-observer variability (intraclass correlation coefficient: ICC > 0.75), (2) evaluation of prognostic performance for FWC-TF, and (3) correlation of prognostic imaging signatures with gene mutation (GM) profile. Of 32 FWC-TF with ICC > 0.75, 18 correlated with total lesion glycolysis (TLG, highest: rs = −0.547, p = 0.002). Using optimized cut-off values, five MR FWC-TF identified a good prognostic group with zero mortality (lowest: p = 0.017). For the most statistically significant prognostic marker, favorable prognosis was significantly associated with a higher number of GM per patient (medians: 7 vs. 1.5, p = 0.009). FWC-TA derived from routine PET/MRI Dixon acquisitions shows good inter-operator agreement, generates biological relevant information related to TLG, GM count, and provides prognostic information that can unlock new clinical applications for CRC patients.
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Waqar, Mirza, Rahmi Sukmawati, Yaqi Ji, and Josaphat Sri Sumantyo. "Tropical PeatLand Forest Biomass Estimation Using Polarimetric Parameters Extracted from RadarSAT-2 Images." Land 9, no. 6 (2020): 193. http://dx.doi.org/10.3390/land9060193.
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This paper was aimed at estimating the forest aboveground biomass (AGB) in the Central Kalimantan tropical peatland forest, Indonesia, using polarimetric parameters extracted from RadarSAT-2 images. Six consecutive acquisitions of RadarSAT-2 full polarimetric data were acquired and polarimetric parameters were extracted. The backscattering coefficient ( σ o ) for HH, HV, VH, and VV channels was computed respectively. Entropy (H) and alpha ( α ) were computed using eign decomposition. In order to understand the scattering behavior, Yamaguchi decomposition was performed to estimate surface scattering ( γ s u r f ) and volume scattering ( γ v o l ) components. Similarly following polarimetric indices were computed; Biomass Index (BMI), Canopy Structure Index (CSI), Volume Scattering Index (VSI), Radar Vegetation Index (RVI) and Pedestal Height ( p h ). The PolSAR parameters were evaluated in terms of their temporal consistency, inter-dependence, and suitability for forest aboveground biomass estimation across rainy and dry conditions. Regression analysis was performed between referenced biomass measurements and polarimetric parameters; VSI, H, RVI, p h , and γ v o l were found significantly correlated with AGB. Biomass estimation was carried out using significant models. Resultant models were validated using field-based AGB measurements. Validation results show a significant correlation between measured and referenced biomass measurements with temporal consistency over the acquisition time period.
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Savanovic, Milovan, Bojan Strbac, Drazan Jaros, and Jean-Noel Foulquier. "The assessment of consecutive 4D-CT scans during simulation for lung stereotactic body radiation therapy patients." Polish Journal of Medical Physics and Engineering 26, no. 4 (2020): 193–99. http://dx.doi.org/10.2478/pjmpe-2020-0023.
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Abstract Purpose: To evaluate the breathing amplitude, tumor motion, patient positioning, and treatment volumes among consecutive four-dimensional computed tomography (4D-CT) scans, during the simulation for lung stereotactic body radiation therapy (SBRT). Material and methods: The variation and shape of the breathing amplitude, patient positioning, and treatment volumes were evaluated for 55 lung cancer patients after consecutive 4D-CT acquisitions, scanned at one-week intervals. The impact of variation in the breathing amplitude on lung tumor motion was determined for 20 patients. The gross tumor volume (GTV) was contoured from a free-breathing CT scan and at ten phases of the respiratory cycle, for both 4D-CTs (440 phases in total). Results: Breathing amplitude decreased by 3.6 (3.4-4.9) mm, tumor motion by 3.2 (0.4-5.0) mm while breathing period increased by 4 (2-6) s, inter-scan for 20 patients. Intra-scan variation was 4 times greater for the breathing amplitude, 5 times for the breathing period, and 8 times for the breathing cycle, comparing irregular versus regular breathing patterns for 55 patients. Using coaching, the breathing amplitude increases 3 to 8 mm, and the breathing period 2 to 6 s. Differences in the contoured treatment volumes were less than 10% between consecutive scans. Patient positioning remained stable, with a small inter-scan difference of 1.1 (0.6-1.4) mm. Conclusion: Decreasing the inter-scan breathing amplitude decreases the tumor motion reciprocally. When the breathing amplitude decreases, the breathing period increases at inter- and intra-scan, especially during irregular breathing. Coaching improves respiration, keeping the initial shape of the breathing amplitude. Contoured treatment volumes and patient positioning were reproducible through successive scans.
Dissertations / Theses on the topic "Consecutive acquisitions"
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Vieira, Tiago Nuno Fernandes. "Evidência sobre aquisições consecutivas pela mesma empresa compradora." Master's thesis, 2013. http://hdl.handle.net/1822/24958.
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Dissertação de mestrado em Finanças<br>O presente estudo procurou evidência empírica relativamente às rendibilidades que as empresas
compradoras conseguiam quando iniciavam uma série de aquisições consecutivas. A literatura
revela que estas rendibilidades variam consoante o tipo de empresa que se adquire, método de
pagamento utilizado e tamanho relativo do negócio. Revela ainda que o padrão das
rendibilidades na série de aquisições consecutivas pode ser positivo ou negativo.
Através da metodologia de estudo de eventos e seguindo o modelo de mercado ajustado para as
janelas de evento de três, cinco e onze dias à volta do anúncio de aquisição, procurou-se, por
intermédio de análise univariada e multivariada, descobrir evidência sobre como o tipo de
empresa adquirida, o método de pagamento utilizado e o tamanho relativo do negócio
influenciavam as rendibilidades anormais. Foi também analisado o padrão das rendibilidades ao
longo da série de aquisições.
As empresas compradoras pertencem ao mercado do Reino Unido e as empresas alvo ao
mercado da UE15. As aquisições consecutivas foram definidas como a compra de três ou mais
empresas num espaço de cinco anos. Poderiam ser adquiridas empresas públicas, privadas e
subsidiárias e a transação foi dividida entre negócios a dinheiro e negócios a outros métodos.
Os resultados demonstram que as aquisições geram rendibilidades positivas para a empresa
compradora de 1,37% e que, a aquisição de empresas privadas e subsidiárias revelam
rendibilidades positivas. Dentro dos diferentes métodos de pagamento, a aquisição de empresas
privadas obtém rendibilidades superiores quando a compra é efetuada a outros métodos e as
subsidiárias quando a aquisição é efetuada a dinheiro. Os resultados mostram também que
existe um padrão negativo nas rendibilidades da série de aquisições. A análise para o tamanho
relativo conclui que, à medida que este aumenta, existe um aumento das rendibilidades para a
empresa compradora quando adquire empresas privadas ou subsidiárias. O inverso acontece
com compra de empresas públicas.<br>This paper searches for empirical evidence about acquirer company returns when they engage in
a series of consecutive acquisitions. Literature tells that these returns are influenced by the
status of the target company, the method of payment, and the relative size of the deal.
Furthermore, it reveals that the returns pattern can be either positive or negative.
Through event study methodology and using the adjusted market model for three, five, and
eleven event window days and doing univariate and multivariate analysis, it was investigated what
kind of influence the target company status, the method of payment, and the relative size of the
deal have in the acquirer company returns. It was also analyzed which pattern the returns have
during the series of acquisitions.
The acquirer companies are public companies based on the United Kingdom and the target
companies are from EU15. A company is classified as frequent acquirer and makes consecutive
acquisitions in case of three or more acquisitions during a five-year period time. Target company
status is divided in public companies, private companies, and subsidiary companies. The method
of payment is divided in cash deals and non-cash deals.
The results show that acquirer companies have positive and significant returns of 1.37%. They
also show that the acquisition of private or subsidiary companies yield positive returns. Analyzing
the method of payment, it shows that the returns of private companies’ acquisitions are higher
when it is a non-cash deal. The acquisition of subsidiary companies yields higher returns when
the deal is made in cash. The results also show that consecutive acquisitions have a negative
pattern, meaning that the first acquisitions from the series have higher returns than the last ones.
The analysis of the relative size shows that there is a positive relation between the increase in the
relative size and higher returns. This is true for the acquisition of private and subsidiary
companies but, when the acquired company is public, it has the opposite effect.
Book chapters on the topic "Consecutive acquisitions"
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Lee, Christine U., and James F. Glockner. "Case 17.18." In Mayo Clinic Body MRI Case Review, edited by Christine U. Lee and James F. Glockner. Oxford University Press, 2014. http://dx.doi.org/10.1093/med/9780199915705.003.0436.
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39-year-old woman with Crohn disease and suspected primary sclerosing cholangitis Consecutive IP images from a 2D SPGR IP-OP acquisition (Figure 17.18.1) demonstrate high signal intensity within the IVC and hepatic veins on the superior 2 images which disappears on the bottom images. Note the appearance of high signal intensity within the aorta and celiac artery on the inferior images....
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Lecumberri, Esther, and Victoria Pastor-González. "Learner generated digital content: from posters to videos to promote content acquisition in a language class." In Five years of ELEUK conferences: a selection of short papers from 2019. Research-publishing.net, 2020. http://dx.doi.org/10.14705/rpnet.2020.41.1078.
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This article explores the use of Learner Generated Digital Content (LGDC) in the context of advanced Spanish language modules. An approach to learning and teaching frequently used and extensively researched in disciplines such as medicine and natural sciences, LGDC has in recent years made a cautious appearance in the area of modern languages (Lambert, Philp, & Nakamura, 2017). In the present case, LGDC becomes a powerful tool to address the challenge of introducing content acquisition in what is primarily a language module. Through the creation and sharing of a range of archivable learner generated digital material (posters and videos), learners and teachers collaborate to develop a living and open access information resource that can be expanded and used by successive cohorts of students in a cumulative process of knowledge generation and knowledge exchange. Scheduled at different points throughout the term and designed to result in texts of increasing linguistic complexity, these tasks encourage students to engage with the process of content acquisition and provide them with opportunities to practise and refine the linguistic skills required for the successful completion of their final assessment (an individual presentation). The introduction of LGDC in the module teaching and learning strategy led to a noticeable increase in student engagement, as evidenced by the results of questionnaires conducted with three consecutive cohorts. By sharing our experience, we would like to encourage fellow practitioners to introduce LGDC in the language classroom.
Conference papers on the topic "Consecutive acquisitions"
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Wong, Chan, Laine Mears, and John Ziegert. "Dead Time Compensation for a Novel Positioning System via Predictive Controls and Virtual Intermittent Setpoints." In ASME 2009 International Manufacturing Science and Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/msec2009-84156.
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Predictive control and intermittent setpoints are proposed to overcome the dead time that problem occurs in a new class of high precision position sensor for manufacturing equipment. In place of a rotary encoder or linear glass scale, a combination of a digital camera and a Liquid Crystal Display (LCD) screen is used to actively monitor two dimensional position changes on an XY table. In order to achieve precise spatial resolution, an actively-controlled planar pixel matrix is used as the tracking target for the system. A digital camera senses the location of the moving image displayed on the LCD screen and provides 2 dimensional position feedback. Thus, the timing and the quality of the visual feedback to the controller are the significant factors to determine the accuracy of the system. Due to the long image processing time, the vision feedback of the actual position of the stage is delayed. At the same time, with the slow frame capturing rates of the camera, dead time occurs between consecutive acquisitions of feedback signals from the vision system to the motion controller, which is detrimental to the performance of the system. Hence, studies and detailed analysis on different dead time compensation strategies and path planning algorithms have been performed to select the optimal strategy to address these challenges. Based on simulation results, a proposed method for integrating predictive control with virtual intermittent setpoints algorithm to mitigate dead time problem is presented in the final section of the paper.
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Lee, Seong Ro, Hyun Gu Kang, Taehun An, et al. "Acquisition of spread spectrum codes with consecutive correlator outputs in the presence of fractional Doppler frequency offset." In 2009 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (PacRim). IEEE, 2009. http://dx.doi.org/10.1109/pacrim.2009.5291320.
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Chuang, Wei-Liang, Kuang-An Chang, and Richard Mercier. "Green Water Flow on a Fixed Model Structure in a Large Wave Basin Under Random Waves." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77184.
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Green water generated by random waves on a fixed, simplified geometry model structure was measured in a large wave basin. The velocity field of the flow that is aerated and highly turbulent was quantified using the bubble image velocimetry (BIV) technique. BIV utilizes shadow textures created by air-water interfaces as tracers in backlit images recorded by a high speed camera. The tracers in consecutive images are then cross-correlated to obtain the corresponding two-dimensional velocities. Random waves were generated by the JONSWAP spectrum with a significant wave height close to the freeboard. An image-based triggering method was employed to detect the green water events and trigger image acquisition. A total of 179 green water events were collected and categorized into three different types, based on the flow behavior. That includes the collapse of overtopping wave, fall of bulk water, and breaking wave crest. Statistical distributions of maximum green water velocities under random waves were developed, while the lognormal distribution was found as the best fit. By modeling the green water as a dam break flow, the Ritter solution was found to be able to capture the horizontal velocity distribution for the random green water events. A prediction equation for the green water velocity distribution under random waves was also obtained.
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Pernía-Espinoza, Alpha, Enrique Sodupe-Ortega, Fco Javier Martinez-de-Pison-Ascacibar, Ruben Urraca-Valle, Javier Antoñanzas-Torres, and Andres Sanz-García. "Assessment of microproject-based teaching/learning (MicroPBL) experience in industrial engineering degrees." In Third International Conference on Higher Education Advances. Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/head17.2017.5167.
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An assessment program to evaluate microproject-based teaching/learning (MicroPBL) methodology on the technical subject ‘Manufacturing Technology’ was implemented for four consecutive academic years. Students from three different engineering degrees were involved providing feedback through different surveys that allowed us to perform a proper evaluation. More specifically, students’ surveys were anonymous after each academic year, except the last one, in which non-anonymous pre and post-surveys were conducted. The surveys were meant to evaluate the acquisition of specific competences (using technical questions about the subject) as well as generic competences (using questions concerning soft-skills). We also checked the students’ satisfaction with the methodology and with the signature in general. Using non-anonymous surveys allowed us to correlate results with the student’s final scores. Students’ self-assessment concerning their knowledge about technical aspects drastically changed after the course. The average of the subject’s final score from student’s perception was slightly higher than the actual value. Student’s self-perception on soft-skills was also increased at the end of the course. The MicroPBL methodology demonstrated beneficial for the case of this technical subject as it maintained high motivation levels in students, which were directly related to students’ success rates and final scores.
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Mai, Vanessa, Susanne Wolf, Paul Varney, Martin Bonnet, and Anja Richert. "DIGITAL ENGINEERING: COMPETENCE ACQUISITION AND PROGRAM DEVELOPMENT AS AN OPEN CO-CREATION PROCESS." In International Conference on Education and New Developments. inScience Press, 2021. http://dx.doi.org/10.36315/2021end090.
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Dealing with the increasingly complex interrelationships in companies, technologies and markets requires engineers to have a holistic, systemic understanding of digital change. Future engineers need future skills and must be able to react to ever faster changing technical requirements by independently expanding their knowledge, developing (technology-based) solution strategies as well as designing, evaluating and communicating these with regard to social, ecological and cultural aspects and requirements. In order to integrate these future skills into existing curricula, study programs must be designed in such a way that they are permeable to continuous and agile adaptation in relation to new knowledge and new technologies. This process can only succeed if universities see themselves as open learning systems that promote co-creation processes among all university stakeholders. The Faculty of Process Engineering, Energy and Mechanical Systems at TH Köln/University of Applied Sciences has recently recognized the resulting need for a transformation process in program development and has further developed the consecutive master's program "Mechanical Engineering/Smart Systems", in which agile learning environments and innovation spaces are created. However, the redesign and further development of modules is not enough. A holistic, systemic understanding in dealing with transformative technologies requires a cultural change in which lecturers and students shape the digital transformation on an equal footing. In a joint learning and research process, they iteratively and agilely test which competencies best prepare students for an increasingly digitalized workplace and which analog and virtual learning spaces this requires. As part of the project "Digital Engineering - Competence Acquisition for Mechanical Engineers in the Digital Age", the faculty is currently implementing the Technology Area, a measure whose aim is to accompany these digital transformation processes at the faculty and to provide lecturers and students with the necessary freedom to experiment with new technologies in teaching. Here, subject-specific teaching and research concepts for the use of new technologies are to be developed and tested together in a co-creation process. The first concepts developed in the Technology Area as well as other Best Practices from the faculty will be presented in the paper. These include the Mixed-Reality-Game FutureING, the Serious Game Worlds of Materials and the development of a StudiCoachBot. In order to promote co-creation processes within and outside the university, a Digitalization Conference was held in May as part of the project to present innovative and forward-looking innovations in engineering education. The reflection of all of the presented initiatives is structurally anchored and professionalized by the House of Excellence in Engineering Education.
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Azzouz, Salim, Johnny Blevins, Tyler Thomas, et al. "Data Collection and Analysis Using a Wind Turbine and a Photovoltaic Solar Panel." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-11751.
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Abstract A weather data collection study is currently conducted using a renewable energy training system. The system is composed of a LabVolt trainer, two sun tracking photovoltaic solar panels and a small wind turbine. The LabVolt training system is located in one of the McCoy School of Engineering laboratories, the solar panels and the wind turbine are located in the neighborhood of the Engineering building at Midwestern State University in Wichita Falls, Texas. A set of meteorological data collecting outdoor sensors to monitor the impact of weather conditions on the power generation of the sun-tracking photovoltaic solar panels and the wind turbine have been installed on the building roof. Weather parameters such as atmospheric temperature, pressure, humidity, and rainfall are monitored using a Davis Vantage Pro 2 data collecting system. A number of LabVIEW data acquisition cards and signal processing modules are used to monitor the sun-tracking photovoltaic solar panels’ output voltage, the wind turbine output voltage, the atmospheric temperature, the solar irradiance, and the wind direction, speed, and RPM. A voltage divider has been built to step down the 90V DC voltage produced by the solar panels to 12V DC voltage required for the trainer electrical circuits. A LabVIEW data processing program is used to create instantaneous graphic displays of the collected data on a monitoring screen. The LabVolt trainer is equipped with two charge controller electronic devices, one is used for the sun tracking photovoltaic solar panels, and one is used for the wind turbine. They are used to control the flow of electrical energy through a set of electrical loading devices and a set of storages batteries. Additionally, the LabVolt trainer is equipped with two kilowatt-hour-meters counting the electrical energy consumed by the electrical loads. The trainer is also equipped with two inverters transforming the 12 V DC voltage collected from both energy producing devices to 120 V that can be used by the electrical loading devices. A brief description of all used electronic components and devices is provided in the paper, as well a detailed experiment set-up with a procedure to run them. The project has been divided into three consecutive phases. The first phase dealt with connecting the solar panels, wind turbine, and data collecting sensors to the LabVIEW data acquisition software. The second phase is currently dealing with setting up the trainer solar and wind electricity providing circuits. In the third upcoming phase, it is expected that the data collected by the sensors will be gradually archived using Excel files and analyzed for weather data correlation purposes. It is also expected that the training system will be used to teach upcoming mechanical engineering students about how to set up an independent renewable energy system and the necessary equipment required to run it.
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Lei, Ting, Michiko Hamada, Adam Donald, and Takeshi Endo. "ROBUST SONIC LOG TRACKING USING A MULTI-RESOLUTION APPROACH." In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0102.
Full textAbstract:
Borehole acoustic logging is an acquisition method that is regarded as the most efficient and reliable method to measure subsurface rock elastic property. It plays an important role in both well construction and reservoir evaluation. The acquisition is carried out downhole by firing a transducer and then collecting waveforms at an array of receivers. A signal processing technique such as the slowness-time-coherence method is used to process array waveform data to resolve slownesses from different arrivals. To label these slowness values, a classification algorithm is then required to first determine if a primary (P) or a secondary (S) arrival exists or not, and then label out the existing ones at each depth of the entire logging interval to deliver continuous compressional and shear slowness logs. Such a process is referred as automatic sonic log tracking process. Clearly, it is of great importance to be able to track log as accurately as possible. Traditional approaches either use predefined slowness or arrival time boundary to distinguish them or treats slowness peaks in consecutive depths like “moving particles” and use a particle tracking algorithm to estimate their trace. However, such a tracking algorithm is often challenged by a sudden change in formation types at bed boundary, fine-scale heterogeneity, downhole logging noise, as well as unpredicted signal loss due to bad borehole shape or gas influx. Consequently, the tracking process is often a tricky task that requires heavy manual quality control and relabeling process, which poses significant bottleneck for a timely delivery of sonic logs for downstream petrophysical and geomechanical applications. In this paper, we propose a new physical based multi-resolution tracking algorithm that can improve the robustness of the tracking process. The new algorithm is inspired by the fact that different resolution sonic logs can sense different rock volumes and therefore response differently to a thin layer or an interval with bad borehole conditions. It works by grouping slowness-time peaks with different resolutions to form clusters, which are then tracked by the connecting with its neighboring depths. As different resolution slownesses are physically constrained by the convolution response of heterogeneous layers, the cluster-based multi-resolution tracking approach exhibits better logging depth continuity than the traditional single-resolution methods. Outliers due to noise can be confidently avoided. Finally, remaining gaps due to shoulder bed boundary can be patched by a convolution constrained optimization process from coherences from different resolutions. This new approach is therefore referred as a multi-resolution approach and can significantly improve sonic log tracking accuracy than the single resolution approach. This new algorithm has been tested on several sonic logging field data and demonstrates robust tracking performance of sonic P&S logs. Additionally, with the multi-resolution processing, sonic logs with different resolution can be reliably obtained and a high-quality high-resolution sonic log can also be automatically delivered, which can then be used to match resolution of other petrophysical logs for various types of interpretation.
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Xu, Lei, Lei Hou, Yu Li, Zhenyu Zhu, Jiaquan Liu, and Ting Lei. "Mid-Term Energy Consumption Prediction of Crude Oil Pipeline Pump Unit Based on GSCV-SVM." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21135.
Full textAbstract:
Abstract Energy consumption prediction plays an important role in pipeline operation regulation and energy management. Accurate energy consumption prediction is helpful to make important decisions, including unit commitment, batch scheduling, load dispatching, energy consumption target setting, etc. The energy consumption of crude oil pipeline is mainly the electrical energy of pump unit. The average annual electrical energy consumption of China’s crude oil pipelines accounts for more than half of the annual operating cost of pipelines. Therefore, the prediction of electrical energy consumption of crude oil pipelines is critical. The energy consumption prediction of crude oil pipelines is very complicated. Firstly, it depends on the variables related to operation parameter, crude oil physical property parameter, environmental parameter and equipment parameter. Secondly, its nonlinearity is strong. Thirdly, the available samples are too little. Through the study on the monthly operation data collected by the Supervisory Control And Data Acquisition (SCADA) system and energy consumption analysis, the turnover and the electrical energy consumption is selected as input variable and output variable, respectively. The support vector machines (SVM) is introduced to predict the monthly electric energy consumption of crude oil pipelines driving oil pumps. However, the generalization capability of SVM is highly dependent on appropriate parameter setting, such as penalty coefficient and kernel parameter. The selection of the optimal parameters is critical to achieving good performance in the learning process. Therefore, in order to improve the generalization ability, GridSearchCV was adopted to optimize the hyperparameters of SVM. Taking a crude oil pipeline from Qinhuangdao City, Hebei Province to Fangshan District, Beijing as an example, the actual operation data for four consecutive years (48 months) are used for this study. The data are divided into training set and test set by stratified sampling method, which consist of 28 samples and 20 samples respectively. The mean absolute percentage error (MAPE), root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) on the test set are 3.42, 21.64, 14.31 and 0.94 respectively. Compared with other five state-of-the-art prediction methods in predictive accuracy, the result shows that GSCV-SVM has the best performance in the case of small samples, and the prediction results are in good agreement with the actual data.