Dissertations / Theses on the topic 'Split ends'

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2007.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Pages 327-328 blank.<br>Includes bibliographical references.<br>Conserved signal transduction pathways coordinate all aspects of metazoan development, including cell fate specification, differentiation, and growth. Rather than functioning as completely independent modules, signaling pathways interface to create a web of specific interactions that a cell integrates in a spatial and temporal manner. The Epidermal Growth Factor Receptor (EGFR) and Notch pathways are evolutionarily conserved signal transduction mechanisms that interact intimately to regulate a broad spectrum of developmental processes in metazoa. The molecular bases underlying cross-talk and signal integration between these two pathways are just beginning to be elucidated. In this thesis, we have focused on the role of Split ends (Spen), the founding member of a family of transcriptional co-repressors, as a node of cross-talk between the EGFR and Notch signaling pathways during Drosophila eye development. At the morphogenetic furrow (MF), which marks the wave of differentiation that passes through the imaginal disc eye primordium, Notch signaling is required for establishing and refining the expression of proneural Atonal (Ato). Ato promotes the EGFR pathway's reiterative signaling for progressive and sequential recruitment of cells within each ommatidial facet of the eye.<br>(cont.) Previous studies found that spen functioned within or in parallel to the EGFR pathway during midline glial cell development in the embryonic central nervous system. In vertebrates, Spen orthologs function in repressor complexes that antagonize the transcription of Notch pathway targets. The involvement of Spen proteins in EGFR and Notch signaling in these systems thus motivated us to explore the consequences of loss of spen function with respect to each pathway during eye development. Here we report that Spen acts as both a positive regulator of EGFR signaling and as an antagonist of Notch signaling in the eye. We find that loss of spen results in hyper-activation of the Notch pathway via upregulation of the Notch activator Scabrous. This results in loss of Ato and activated MAP kinase at the MF, therefore antagonizing output from the EGFR signaling pathway. As a consequence, there is a failure of cell fate specification in spen mutant ommatidia. These observations suggest that Spen modulates output from the Notch and EGFR pathways to ensure appropriate patterning during eye development. Additionally, we have characterized a transgene encoding nuclear localization sequence-tagged Spen C-terminus that functions as a dominant-negative (SpenDN).<br>(cont.) The Spen C-terminus contains the evolutionarily conserved SPOC domain that is required for transcriptional repression. In order to identify components related to Spen function and to understand the processes in which Spen may be involved, we performed a genetic screen to identify dominant modifiers of the rough-eye associated with eye-expressed SpenDN. Our results confirm interactions with the EGFR and Notch pathways, but also suggest functions for Spen in chromatin regulation and programmed cell death. As Spen-like proteins are involved in human development and disease, it will be important to elucidate the underlying molecular mechanism behind Spen function.<br>by David Bagon Doroquez.<br>Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2001.<br>Includes bibliographical references.<br>Split ends (spen) was isolated as a strong enhancer of the rough eye phenotype associated with constitutive activation of Yan, implicating spen as a positive regulator of the receptor tyrosine kinase (RTK) signaling pathway. Molecular characterization of spen has revealed that spen encodes a protein with 5476 amino acids. It contains three tandem repeats of an RNA Recognition Motif (RRM) at its N-terminus, suggesting that Spen might function as an RNAbinding protein. Spen also contains a highly conserved SPOC (Spen Pearalogue and Orthologue C-terminal) domain at its C-terminus. Spen-like proteins exist from worms to humans, and they likely define a novel subfamily of RNA-binding proteins based on the RRM sequence similarities. Characterization of spen mutant phenotypes in the context of RTK signaling suggests that spen function is required for normal eye development and wing vein formation, both contexts where RTK signaling has been proven to play important roles. We have focused on the development of Drosophila embryonic midline glial cells (MGCs) and have demonstrated that spen is required for the normal migration and survival of MGCs. Loss of spen leads to aberrant migration and as a consequence, reduced number of midline glial cells. As a result, spen mutant embryos exhibit severe morphology and axonguidance defects in the central nervous system, a phenotype strikingly reminiscent of those seen in spitz group mutants. The phenotypic analysis of spen mutants strongly suggests that spen is a positive regulator of the RTK pathway. Further supporting this hypothesis, we have shown that spen synergistically interacts with pointed. To further investigate the relationship between spen and the RTK pathway, we have generated a dominant negative mutant protein by truncating the C-terminus of Spen including the highly conserved SPOC domain (Spen[Delta]C). Specific overexpression of Spen[Delta]C in the midline glial cells causes lethality, and we have demonstrated that the lethality associated with Spen[Delta]C can be rescued by overexpression of activated Ras vi 2 and activated DER ligand Spitz. Since Spen[Delta]C also suppresses the lethality caused by Ras v12, spen is likely to function genetically downstream of or in parallel to Ras. The implication of a putative RNA-binding protein downstream of the RTK/Ras pathway suggests that there might be post-transcriptional gene regulation mechanisms downstream of Ras to allow the cells quickly and precisely to respond to extracellular signals. In order to elucidate the molecular mechanisms underlying Spen function in the RTK pathway, we have designed a genetic screen to isolate spen-interacting genes. By overexpression of a nuclear-localization-sequence (NLS)-tagged Spen C-terminus (CspenNLS) specifically in the eye, we have generated a rough eye phenotype. Reducing endogenous spen dosage enhances this rough eye phenotype, suggesting that CspenNLS functions as a dominant negative mutant in vivo, possibly by sequestering the spen-interacting proteins. Using this phenotype as a starting background, we screened through the deficiency kit which uncovers - 80% of the Drosophila genome and have isolated 23 enhancing and 27 suppressing regions. Among the modifiers, there are regions uncovering known RTK pathway components, including Draf, sevenless, vein, sevenup, pointed and Ras, consistent with spen functioning as a component of the RTK pathway. Most interestingly, we have isolated multiple overlapping deficiencies as modifiers of CspenNLS, suggesting that these overlapping regions might contain candidate genes directly interacting with spen. Future genetic and biochemical analysis of these candidate genes will likely shed important light on the molecular mechanisms underlying Spen function.<br>by Fangli Chen.<br>Ph.D.

Le gène split end (spen) est impliqué dans de nombreuses voies de signalisation et processus biologiques. Durant ma thèse j'ai étudié le rôle de spen dans la mort cellulaire au cours du développement de la rétine de la Drosophile. L'œil de Drosophile est composé de centaines d'unités appelées ommatidies. Chaque ommatidie est composée de huit photorécepteurs entourés de cellules accessoires comprenant quatre cellules cônes et deux cellules pigmentaires primaires, ainsi que douze cellules interommatidiales. Les cellules interommatidiales adoptent une structure hexagonale parfaitement régulière. Des cellules interommatidiales en excès doivent être éliminées par apoptose au cours du développement. J'ai montré que la modulation de spen modifiait radicalement le patron des cellules interommatidiales. L'inactivation de spen conduit à un défaut de cellules interommatidiales alors que sa surexpression entraîne un excès de ces cellules. Ces résultats témoignent d’un rôle anti-apoptotique de spen. Nous avons aussi montré que la perte des cellules interommatidiales dans un contexte mutant pour spen pouvait être entièrement sauvée en exprimant la protéine p35 connue pour bloquer l'activité des caspases. Comme spen est exprimé de manière ubiquitaire, nous avons cherché à déterminer dans quelles cellules spen jouait son rôle de régulateur de la mort cellulaire. Grâce à une analyse clonale, nous avons pu montrer que c'est au niveau des cellules cônes que spen agit. L'inactivation de spen dans les autres cellules accessoires de l'œil n'influence pas la mort des cellules interommatidiales. Nous avons en outre, montré que spen avait un rôle dans la formation des soies de chaque ommatidie. Ces travaux mettent en évidence un rôle de spen dans le contrôle de la mort cellulaire des cellules interommatidiales dans les cellules cônes. Nos résultats montrent, par ailleurs, que spen serait requis pour le relarguage du facteur de survie Spitz (le ligand activateur de la voie EGF) à partir des cellules cônes. En parallèle, nous avons étudiés le rôle de survie de spen dans un modèle neurodégénératif. Nous avons montré que spen était nécessaire dans les cellules gliales pour la résistance au stress oxydatif. De manière intéressante, nous avons trouvé que l'inactivation de spen dans la glie diminuait l'activité de la voie de signalisation NOTCH. Cette résistance pourrait se faire via la modulation de gènes antioxydants. De manière générale, nos travaux démontrent un rôle du gène split ends dans la survie cellulaire. Ce facteur agit de manière non-autonome à partir des cellules supports de différents organes<br>In metazoan, the successful development of many organs requires the elimination of supernumerary cells by apoptosis. For example, the elimination of about two thousand interommatidial cells (IOCs) during Drosophila eye development allows the precise rearrangement of ommatidia in a perfect hexagonal array. Maximal apoptosis occurs during pupal life and the remaining IOCs differentiate into secondary and tertiary pigment cells. The precise removal of unwanted IOCs requires coordinated activation of Notch (pro-death) and EGF (pro-survival) pathways. IOCs undergoing apoptosis express the IAP inhibitor Hid, which leads to the activation of initiator and effector caspases. However, the mechanisms that coordinate the death and survival pathways for timed and precise IOC removal are poorly understood.Here, we report that spen encodes a nuclear protein expressed in the pupal eye that is required for IOC survival. We showed that the inhibition of spen, by either RNAi or in spen mutant clones resulted in disorganized ommatidia with missing IOCs. Moreover, overexpression of spen leads to extra IOCs. These results indicate that spen expression promotes IOC survival during eye development. Importantly blocking apoptosis prevents the loss of IOC in a spen mutant retina. Spen is a protein known to be ubiquitous in tissue during development. Indeed, we have shown using an enhancer trap line that spen is expressed in all the cells in the eye pupal disk. To better understand where spen is acting from in this tissue to regulate cell death, we performed a clonal analysis. We found that the inactivation of spen in the cone cells was causing the loss of IOC, indicating that spen is required non-autonomously in cone cell for IOC survival. In parallel we have shown that the inactivation of spen was disrupting eye bristles morphology. Even if studies discuss the role of bristles in the regulation of developmental apoptosis in this context, our clonal analysis excluded this possibility. Furthermore, we found that spitz, the EGFR ligand, accumulate in cone cells upon spen inactivation. Our current hypothesis is that spen is likely to be required for the release of Spitz from the cone cells in order to active the survival signaling pathway EGFR in the IOCs. Also, we examined the protective role of spen in a chemical model of Parkinson disease (paraquat treatment). We showed that the glial expression of spen is protective in this context, which suggest against that spen acts non-autonomously. Interestingly we found that the inactivation of spen in glia downregulates the Notch signaling pathway. Spen is likely to be a key factor integrating cues from different signaling pathways to promote cell survival

The current Internet architecture is facing serious scaling problems notably in its routing and addressing system. The TCPIIP stack uses the IP address to identify an endpoint host as well as to serve as a network topological locator. Due to the overloaded semantic of the IP address, mobility is not handled efficiently. Several Locator Identity Split proposals have been developed to decouple the actual semantic of the IP address, separating the endpoint identification and locator functions. For all Locator Identity Split protocols to work a mapping infrastructure is required. However most of the defined solutions tend to focus only on part of the problem space, and usually place end-host mobility aside. We believe that the mapping infrastructure would not scale efficiently with a large number of mobile nodes and would contribute to packet losses while the mobile nodes are moving. This thesis proposes a tiered architecture, which divides the mapping infrastructure into a core mapper and an internal mapper, such that it would scale under is a large number of mobile nodes, store and process their mapping records and provide an up-to-date mapping record. The tiered architecture is implemented using the GSE/8+8 rewriting approach. The core mapper uses a Chord DHT and the internal mapper is a hierarchy of routers with storing and rewriting capability. The tiered architecture is simulated in OMNeT++. The performance of the tiered architecture is evaluated by examining the core mapper and the internal mapper separately by simulating two real network scenarios based on the JANET topology and a University wireless network. The core mapper performance is evaluated against the Domain Name Server (DNS), and the internal mapper is evaluated using the end-host mobility provided by the Host based Identity Protocol (HIP).

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-10T19:51:47Z No. of bitstreams: 1 THIAGO TAKUMI TAN – DISSERTAÇÃO (PPGEM) 2017.pdf: 9018003 bytes, checksum: 45bd9458239c0c274dabe5c7aee2f165 (MD5)<br>Made available in DSpace on 2018-04-10T19:51:47Z (GMT). No. of bitstreams: 1 THIAGO TAKUMI TAN – DISSERTAÇÃO (PPGEM) 2017.pdf: 9018003 bytes, checksum: 45bd9458239c0c274dabe5c7aee2f165 (MD5) Previous issue date: 2017-03-13<br>O objetivo desta dissertação foi desenvolver dispositivos que possam ser utilizados para ensaios de fratura interlaminar modo-I e modo-II em materiais dissimilares, para aplicação de cargas dinâmicas. Para o desenvolvimento dos dispositivos foi utilizada uma adaptação da metodologia de projeto apresentada por Maribondo (2000), que consiste em projeto informacional, projeto conceitual, projeto preliminar, projeto detalhado, fabricação e testes. A escolha dos ensaios que podem ser utilizados para obter tais modos de fratura foi realizada com base no estudo de trabalhos acadêmicos, que apontou o ensaio double cantilever beam (DCB), como sendo o mais utilizado para estudo de fratura interlaminar modo-I, e também foi observado o crescimento do uso do ensaio end-loaded split (ELS), para estudo de fratura interlaminar modo-II. Os dispositivos desenvolvidos foram testados em uma máquina de impacto por queda de peso, onde foram utilizados corpos de prova de junta adesiva de alumínio/epóxi. Realizaram-se testes modo-I e modo-II bem-sucedidos, analisando o comportamento dos dispositivos e dos corpos de prova durante o ensaio e após o mesmo.<br>The main objective of this dissertation for the devices that can be used for mode-I and mode-II interlaminar fracture test in dissimilar materials. For the development of devices for design methodology that projects in informational design, conceptual design, preliminary design, detailed design, fabrication and testing. The choice of the tests that can be used to obtain such fracture modes was made based on the study of academic papers, which pointed to the double beam cantilever (DCB) test, as being the most used for the study of interlaminar mode-I, and end-loaded split (ELS) for the study of mode-II interlaminar fracture. The developed devices were tested in a weight drop impact machine, where aluminum / epoxy adhesive joints were used. Testing and analysis of the behavior of the devices and test bodies were carried out during and after the test.

La majoria de les fallades en elements estructurals són degudes a càrrega per fatiga. En conseqüència, la fatiga mecànica és un factor clau per al disseny d'elements mecànics. En el cas de materials compòsits laminats, el procés de fallada per fatiga inclou diferents mecanismes de dany que resulten en la degradació del material. Un dels mecanismes de dany més importants és la delaminació entre capes del laminat. En el cas de components aeronàutics, les plaques de composit estan exposades a impactes i les delaminacions apareixen facilment en un laminat després d'un impacte. Molts components fets de compòsit tenen formes corbes, superposició de capes i capes amb diferents orientacions que fan que la delaminació es propagui en un mode mixt que depen de la grandària de la delaminació. És a dir, les delaminacions generalment es propaguen en mode mixt variable. És per això que és important desenvolupar nous mètodes per caracteritzar el creixement subcrític en mode mixt per fatiga de les delaminacions. El principal objectiu d'aquest treball és la caracterització del creixement en mode mixt variable de les delaminacions en compòsits laminats per efecte de càrregues a fatiga. Amb aquest fi, es proposa un nou model per al creixement per fatiga de la delaminació en mode mixt. Contràriament als models ja existents, el model que es proposa es formula d'acord a la variació no-monotònica dels paràmetres de propagació amb el mode mixt observada en diferents resultats experimentals. A més, es du a terme un anàlisi de l'assaig mixed-mode end load split (MMELS), la característica més important del qual és la variació del mode mixt a mesura que la delaminació creix. Per a aquest anàlisi, es tenen em compte dos mètodes teòrics presents en la literatura. No obstant, les expressions resultants per l'assaig MMELS no són equivalents i les diferències entre els dos mètodes poden ser importants, fins a 50 vegades. Per aquest motiu, en aquest treball es porta a terme un anàlisi alternatiu més acurat del MMELS per tal d'establir una comparació. Aquest anàlisi alternatiu es basa en el mètode dels elements finits i virtual crack closure technique (VCCT). D'aquest anàlisi en resulten importants aspectes a considerar per a la bona caracterització de materials utilitzant l'assaig MMELS. Durant l'estudi s'ha dissenyat i construït un utillatge per l'assaig MMELS. Per a la caracterització experimental de la propagació per fatiga de delaminacions en mode mixt variable s'utilitzen diferents provetes de laminats carboni/epoxy essencialment unidireccionals. També es du a terme un anàlisi fractogràfic d'algunes de les superfícies de fractura per delaminació. Els resultats experimentals són comparats amb les prediccions del model proposat per la propagació per fatiga d'esquerdes interlaminars.<br>Most of the failures in structural elements in use are a consequence of mechanical fatigue. Therefore, fatigue is a decisive factor in designing durable mechanical elements. In laminated composite materials, the fatigue process involves different damage mechanisms that result in the degradation of the material. One of the most important damage mechanisms is the delamination between plies of the laminate. In aeronautical applications, composite plates are sensitive to impact and delamination occurs readily in composite laminates on impact. Many composite components have curved shapes, tapered thickness and plies with different orientations, which make the delamination grow with a mode mix that depends on the extent of the crack. Thus, delaminations generally grow under varying mode mix. It is therefore important to develop methods that can characterise subcritical, mixed-mode growth in fatigue delamination. The main objective of the present investigation is the characterisation of the variable mixed-mode delamination in composite laminates under fatigue conditions. To this end, a mixed-mode fatigue delamination model is proposed. Oppositely to the mixed-mode fatigue delamination models present in the literature, the proposed model takes into account the non-monotonic variation of the propagation parameters with the mode mix observed in different experimental data. Moreover, the mixed-mode end load split (MMELS) test, which main characteristic is that the propagation mode of the interlaminar crack varies with the crack extent, is analysed. Two theoretical approaches present in the literature are considered. However, the resulting expressions for the MMELS test are not equivalent and the differences between approaches can be up to 50 times. A more accurate alternative analysis of the MMELS test is carried out in the present study for comparison. The alternative analysis is based on the finite element method and the virtual crack closure technique. Significant findings are found for precise materials characterisation using the MMELS test. A MMELS test rig is also designed and built. Different specimens of essentially unidirectional carbon/epoxy laminates are tested for the experimental characterisation of fatigue delamination under varying mode mix. A fractographic analysis is also conducted in some of the delaminated fracture surfaces. The experimental results are compared to the predictions of a proposed model for the fatigue propagation of interlaminar cracks.

Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>The study aimed to evaluate the silvicultural performance of Eucalyptus spp. clones and select superior clones with higher quality of the wood. The material used for the study was from a clonal test of interspecific hybrids of Eucalyptus spp., in the municipality of Tapes - state of Rio Grande do Sul, belonging to company CMPC Celulose Riograndense. The forest stand was established in August 2003, with initial spacing of 3.0 x 3.0 m, containing 138 clones. The clones were grouped by the diameter at breast height (DBH) and overall height (h), and 29 of them were selected for the study. For the sampling of trees DBH, h, bark thickness (EC), dynamic modulus of elasticity (Ed) using ultrasound and longitudinal residual strain (DRL) resulting from growth stresses. The DRL was measured in living trees with the extensometer method CIRAD-Fôret. Afterwards, 58 trees were felled and broken into logs to evaluate end splitting planks were taken to prepare speciments for wood physical and mechanical properties according to D 143-94 - ASTM (2000) standards. The end logs splitting (IRT) was evaluated in the field, covering the logs end during five days for subsequent measurement. The phenotypic variance components and indirect gain selection estimate for the clones in this study were determined by DRL, wood volume (Vsc), basic density (ρpond) and IRT. The clones showed enough genetic variability to be separated into groups according to DHB at three and seven years, and for h at seven years of age. The early selection at three years after planting can be used to identify Eucalyptus spp. clones with best growth. The DRL showed variability among clones, but no correlation with the dendrometric variables. The mean value for IRT was 0.46%. The DRL was highly correlated with TCL and IRT, however the ρpond and mechanical properties showed no correlations with the DRL. The clones belonging to group 1, which present the lowest levels for TCL and consequently lower IRT, can be considered potential for forest breeding programs. Clone selection performed by the variable DRL, Vsc, ρpond and IRT, provided satisfactory genetic gains, by improving the growth characteristics or improving quality of the wood.<br>DESEMPENHO SILVICULTURAL E SELEÇÃO DE CLONES DE Eucalyptus spp. PARA A QUALIDADE DA MADEIRA Autor: Rafael Beltrame Orientador: Dr. Clovis Roberto Haselein Data e Local da Defesa: Santa Maria, 14 de dezembro de 2012. O estudo teve como objetivos avaliar o desempenho silvicultural de clones de Eucalyptus spp. e selecionar clones superiores visando à qualidade da madeira. O material utilizado foi procedente de um teste clonal de híbridos interespecíficos de Eucalyptus spp., conduzido no município de Tapes-RS, pertencente à empresa CMPC Celulose Riograndense. O povoamento foi implantado em agosto de 2003, com espaçamento inicial de 3,0 x 3,0 m, contendo 138 clones. Os clones foram avaliados e agrupados quanto ao diâmetro à altura do peito (DAP) e altura total (h), selecionandose 29 deles para o estudo. Nas árvores, foram medidos o DAP, a h, a espessura de casca (EC), o módulo de elasticidade dinâmico (Ed) com auxílio do ultrassom e a deformação residual longitudinal (DRL) decorrente das tensões de crescimento. A DRL foi medida em árvores vivas, utilizando o extensômetro, pelo método CIRADFôret. Em seguida, 58 árvores foram abatidas e desdobradas em toras para avaliação das rachaduras de topo e confecção de amostras para a realização dos testes físicos e mecânicos, conforme a norma D 143-94 - ASTM (2000). O índice de rachaduras de topo das toras (IRT) foi avaliado a campo, ensacando as extremidades dessas por um período de cinco dias para posterior medição. A estimativa dos componentes da variância fenotípica e o ganho indireto de seleção para os clones do estudo foram determinadas por meio da DRL, volume sem casca (Vsc), massa específica básica ponderada (ρpond) e IRT. Os clones apresentaram variabilidade genética suficiente para serem separados em grupos quanto ao DAP, aos três e aos sete anos, e quanto à h das árvores, aos sete anos de idade. A seleção precoce aos três anos após o plantio pode ser empregada para identificar clones de Eucalyptus spp. com melhor vigor de crescimento. A DRL apresentou variabilidade entre os clones, porém não apresentou correlações com as variáveis dendrométricas. O valor médio do IRT foi de 0,46%. A DRL apresentou alta correlação com a TCL e o IRT, entretanto, a ρpond e as propriedades mecânicas não apresentaram correlações com a DRL. Os clones pertencentes ao grupo 1, por apresentarem os menores níveis para a TCL e, consequentemente, menores IRTs, podem ser considerados potenciais para programas de melhoramento genético florestal. A seleção de clones realizada por meio das variáveis DRL, Vsc, ρpond e IRT proporcionaram ganhos genéticos satisfatórios, tanto para o melhoramento das características de crescimento quanto para a qualidade da madeira.

The design of cultural centre is situated in part Kozia Hôrka( well-known city swimming pool), in its advantage takes natural scenery and calm atmosphere of place. Into action of performance brings a message in form of body of reservoir, function of centre is divided into small parts placed in area Kozia Hôrka. Orientation of objects comes mainly from local natural ispirations. Complex is multifunctional in concept, counts with several sorts of culture - sports events. Whereby the main function of swimming pool is preserved and added for higher comfort of inhabitants. Architecture of objects comes from idea of floating leaf on water level and body of reservoir. Objects stylizely illustrate this idea. The design takes the game of solids of organic and strictly ortogonal shapes. Two mutual opposites, in interaction. Objects smoothy and with respect encroach the environment, which is enough marked by human. Simplicity in used materials ( glass, steel, wood ) give transparency and purity to whole solution.

Timber beams with end splits were investigated in this study to determine their shear strength. Two conditions were considered: a) Group 1 had supports located near the ends with the portion of the beam extending beyond the support, and b) Group 2 had supports located right at the end of the beam subjected to a horizontal split at approximately mid height. In Group 1, seventeen beams were tested under static loading and four were tested in fatigue. In Group 2, nineteen beams were tested under static loading and four under fatigue. In Group 1, eight beams under static loading failed in shear. In Group 2, all beams under static loading failed in shear. Group 1 and Group 2 beams under static load produced average shear strength values of 4.93 MPa and 4.49 MPa, respectively. During fatigue tests, Group 1 sustained more cycles than beams in Group 2.

碩士<br>國立臺北科技大學<br>電腦與通訊研究所<br>100<br>In the modern generation of digitally high-speed data transmission, multiple power level demands may be required. In the view of signal integrity, the worst case is to cut completely a slit on the ground plane during traces traversing over because the scenario like that will lead to serious signal quality and crosstalk problems. So here we proposed one new solution to improve signal quality and far-end crosstalk (FEXT) by using interdigital capacitor. The basic working principle of this structure is by the property of the displacement capacitor and needs no extra components. The experimental results indicated that our solution could improve signal quality and reduce FEXT by 29.87% and 8.87% in the time domain, respectively. And the result of eye diagram under 6 Gbps bit rate also showed the improvement of eye height 59% and eye width 7%. The statement above showed that our design requires no extra components to improve signal quality and reduce FEXT.

碩士<br>逢甲大學<br>交通工程與管理所<br>92<br>The topics of this thesis are about accidents in possible road sections. This study considers all kinds of factors, including driving movements(starting driving from roadside, lane-changing or overtaking), degree of drinking, degree of speeding, impact of collision, whether or not one car sees the other before collision and the distance between two involved cars when one sees the other. The study collects accidents data from the provincial reauthenticated organization during three and a half years since March, 2000. This research proposes a model formulation to discuss liability and casualties by multinomial logits. The responses of liability include full, major, equal, minor, and zero. Due to lack of data with lane-changing parties who need to take zero liability, the five outcomes of original logit models are reduced into four. There are two possible responses in casualties models, including casualties consisting of injuries or fatalities and no casualties. The study tries to estimate the effects of variables on both liability and casualties for lane-changing and keeping drivers. The first step of this study is to construct independent and chain models of both liability and casualties for lane-changing drivers and of only casualties for lane-keeping drivers using early data in two and a half years. The formulation process of a chain model is divided into two stages. Liability estimated by the first stage from a liability model is used as an influencing factor at the second stage for a casualty model. Since the liabilities of the lane-changing and keeping drivers are added together to be full responsibility, it is just necessary to construct the lane-changing drivers liability model at the first stage. The variables of the independence model for casualty includes not only the influential variables but also the original liability. One year newer data are used to test the outcome of all the mentioned models using early data by calculating the percentage correct predicition. It shows that the percentage of correct prediction is about 30%. This results expain, different members or the same working for a long duration members in the authentication committee may make different decisions by con -sidering different factors in different ways for lane-changing and keeping drivers. Therefore, this study still need to formulate the other groups of models from data in three and a half years with one year of extra data added. This study then move on to construct chain models from liability towards casualties. The major point of doing a chain model is to understand whether or not the affecting variables of liability can predict casualty via liability. Hopefully, from these results, parties who have liability can watch out for both outcomes of taking responsibility and possibly being injuried. While the purpose of the independence model is to find out if the liability and other significant factors can directly affect casualties, i.e. parties who take less liability will suffer from serious injuries or not. By comparing results of the independence model with those of the chain models, the direct and indirect effects of variables on casualties tendency can be understood. The study results indicate, impact of collision, braking or not for lane-changing drivers and degree of speeding for lane-keeping drivers significantly affect the liability of lane-changing drivers and this estimated liability at the first stage will be used as an influencing factor at the second stage for casualties of lane-keeping drivers. For a quantitative example, the casualties’ odds of zero liability are 7.35 times that of major liability for lane-keeping drivers, thus there is a conclusion that an involved lane-keeping driver who takes zero liability tends to suffer from casualty.