Presently, the industry accepted method for determining the positive moment strength of gravity loaded standing seam metal roof systems is the "Base Test Method". The Base Test Method provides a means for determining the positive moment strength of a multiple span, multiple purlin line standing seam roof system using the results from a set of six single span, simply supported, two-purlin line experimental tests. A set of six base tests must be conducted for each combination of purlin profile, deck panel profile, clip type, and intermediate bracing configuration. The primary objective of this study is to investigate the possibility of eliminating some of the roof system parameters specifically, clip type, purlin flange width, and roof panel thickness. This study used the results from nine series of tests. Each series consists of 11 to 14 gravity loaded base tests. The first three series were used to examine the effects of clip type on the strength of standing seam roof system. The final six series was used to examine the effects of flange width and roof panel thickness. All nine series were constructed using Z-purlin sections with flanges facing the same direction (like orientation). Based on the results of this study, clip type, purlin flange width, and roof panel thickness all have an effect on the strength of standing seam roof systems. Although none of the roof components can be completely eliminated from the required test matrix, by using trend relationships an acceptable test protocol was developed that results in a significant reduction in the number of required base tests. / Master of Science

[pt] A presente tese analisa o problema da redução de ganho entre aberturas circulares situadas em região de Fresnel, tendo como objetivo a determinação do fator de correção a ser introduzido nas medidas de ganho em campo próximo. Para duas diferentes famílias de iluminação nas aberturas, são apresentados um conjunto de tabelas para o fator de redução de ganho bem côo suas curvas correspondentes. / [en] The following work analyzes the problem of gain reduction between circular apertures located in the Fresnel region, and aims to determine the correction factor to be applied when measuring near field gains. Two different sets of aperture illumination forms are presented, for which sets of tables of the reduction factor as well as the corresponding curves have been developd.

Freeway merging VISSIM calibration techniques were developed for the analysis of ramp metering in Georgia. An analysis of VISSIM’s advanced merging and cooperative lane change settings was undertaken to determine their effects on merging behavior. Another analysis was performed to determine the effects of the safety reduction factor and the maximum deceleration for cooperative braking parameter on the simulated merging behavior. Results indicated that having both the advanced merging and cooperative lane change setting active produced the best results and that the safety reduction factor had more influence on the merging behavior than the maximum deceleration for cooperative braking parameter. Results also indicated that the on-ramp experienced unrealistic congestion when on-ramp traffic was unable to immediately find an acceptable gap when entering the acceleration lane. These vehicles would form a queue at the end of the acceleration lane and then be unable to merge into the freeway lane due to the speed differential between the freeway and the queued ramp traffic. An Incremental Desired Speed algorithm was developed to maintain an acceptable speed differential between the merging traffic and the freeway traffic. The Incremental Desired Speed algorithm resulted in a smoother merging behavior. Lastly, a ramp meter was introduced and an increase in both the freeway throughput and overall speeds was found. Implications of these findings on the future research is discussed.

回顧二十世紀的歷程，我們可以看到人類在壽命上的一大進步，認為壽命的延長是人類的最大勝利；但是此壽命延長現象卻視為未來社會中的最主要的挑戰與風險。台灣在1993年六十五歲以上的老年人口比例已突破7%，正式步入聯合國所定義的「高齡化社會」，也正式面臨長壽風險（Longevity Risk）的問題。人口老化所帶來的衝擊，不只是提高工作人口的負擔，它同時也增加政府的養老給付和醫療保險支出，影響社會經濟安全，因此對於未來人口推估的死亡率模型所扮演角色日益重要。本研究以移動平均法和主成分分析兩種不同方式討論不同國家的死亡率變化情形，而後分析廣為人所用的Lee-Carter模型及Reduction Factor模型不足之處，並針對此兩模型不完善部分加以調整改進，建構出適合台灣死亡率的預測模型。

隨著醫療的普及與生活品質的改善，人類的死亡率持續的下降。壽命的延長是人們夢寐以求的理想，但是隨著壽命延長，人類隨之要面臨許多衍生而來的問題，諸如退休規劃、醫療照顧等問題。面臨延壽風險的問題，現行最急迫的課題莫過於探討人口死亡率預測模型。對於死亡率預測的模型，國外已有相當多的研究，近年來也看到國內有許多學者紛紛投入死亡率的研究，由於目前英國實務上所使用Reduction Factor模型，在國內尚無相關的研究，故本文以Reduction Factor模型為基礎，並透過與Lee-Carter模型的比較與各國死亡率資料的驗證，進一步加以改善並建構出適用於台灣地區死亡率預測的模型，以作為往後用來衡量延壽風險的依據。

Cross frames are critical components in steel bridge systems. Cross frames brace girders against lateral torsional buckling and assist in distributing live loads to girders during the service life of the bridge. In curved bridges, cross frames also serve as primary structural members in resisting torsion generated by the traffic loads. The conventional cross frames are often constructed in X- or K- type shapes with steel angle sections. However, the actual stiffness of these cross frames are not well understood or quantified, leading to potentially inaccurate prediction of bridge behavior and safety during construction and in service. Previous studies have shown the possibility of employing new sections, such as tubular members and double angles, in cross frame designs. In addition, a type-Z cross frame, or single diagonal cross frame was also found to be a potential use to simplify the design. However, the effectiveness of these innovative cross frame types has not been completely examined. And these new cross frames have yet compared with the conventional ones in terms of their stiffness and strength capacity. This dissertation documents the results of a study on the stiffness of various types of cross frame systems. Full size cross frames were tested to establish actual stiffness of the cross frames specimens. The tests results revealed a significant discrepancy between the actual measured stiffness and the stiffness calculated using methods commonly employed by bridge designers. The research showed that the major source of this discrepancy was eccentricity in the connection. The stiffness reduction was quantified by employing analytical derivation and finite element modeling. As a result, methods were developed to account for the stiffness reduction. / text

Στόχος της παρούσας εργασίας είναι η παραμετρική μελέτη μεταλλικών καμπτικών επίπεδων πλαισίων με υποστυλώματα διατομής τύπου τετραγωνικής κοιλοδοκού (Square Hollow Section, SHS) και δοκών διατομής τύπου διπλού ταυ (IPE). Ζητούμενο αποτελεί η ανάπτυξη εξισώσεων που συνδέουν χαρακτηριστικά της ανελαστικής απόκρισης των κατασκευών. Βασική επιδίωξη είναι η δυνατότητα πραγματοποίησης αντισεισμικού σχεδιασμού σύμφωνα με την μέθοδο των δυνάμεων έχοντας όμως σαν αρχικό στόχο ένα επιθυμητό επίπεδο επιτελεστικότητας σύμφωνα με τη μέθοδο σχεδιασμού που βασίζεται στις μετακινήσεις. Επίσης, αναπτύχθηκαν εξισώσεις που προβλέπουν την καθ’ ύψος κατανομή των ελαστικών και ανελαστικών μετακινήσεων της κατασκευής. Αναδεικνύεται η επιρροή του ελέγχου ευστάθειας στον σχεδιασμό μεταλλικών καμπτικών πλαισίων. Χρησιμοποιούνται διάφορες παράμετροι που εκτιμήθηκε πως επηρεάζουν την ελαστική και ανελαστική απόκριση των κατασκευών όπως το όριο διαρροής του χάλυβα fy των μελών, ο αριθμός των ορόφων ns, που επηρεάζει άμεσα την ιδιοπερίοδο του συστήματος, η μορφή της ελαστικής απόκρισης των κατασκευών, οι οποίες διακρίνονται σε καμπτικού και διατμητικού τύπου (shear type, flexural type) σύμφωνα με τον συντελεστή ρ όπως ορίζεται από τον Chopra (2007a), καθώς επίσης και την παράμετρο πλαστικών ροπών a που σχετίζεται με το είδος του αναπτυσσόμενου ανελαστικού μηχανισμού. Ο υστερητικός νόμος που χρησιμοποιήθηκε και περιγράφει την ανελαστική απόκριση των μελών υπό ανακυκλιζόμενη δράση, ταυτίζεται με τον διγραμμικό υστερητικό νόμο με κράτυνση 3% προσομοιώντοντας παράλληλα και την απομείωση της αντοχής των μελών που συνδέεται άμεσα με την τοπική πλαστιμότητα τους σε κάθε ανελαστικό κύκλο φόρτισης. Παραμετρικές αναλύσεις έγιναν επίσης με τη χρήση διγραμμικού νόμου υστέρησης με κράτυνση 3% χωρίς την απομείωσης της αντοχής των μελών κατά την ανελαστική τους απόκριση, με στόχο την διερεύνηση της επιρροής στην αντοχή των μελών κατά την ανελαστική τους απόκριση. Για την πραγματοποίηση της παρούσας μελέτης 57 καταγραφές παρελθοντικών σεισμών μακριά από το σεισμικό ρήγμα, αποτέλεσαν την διέγερση για την εκτέλεση των δυναμικών μη-γραμμικών αναλύσεων ώστε να ληφθεί υπόψη η επιρροή του συχνοτικού περιεχομένου των επιταχυνσιογραφημάτων στην απόκριση των συστημάτων. Τέλος, παραδείγματα που συγκρίνουν την μέθοδο που παρουσιάζεται με την μέθοδο των δυνάμεων αποδεικνύουν την αποτελεσματικότητα της μεθόδου. / An efficient procedure to estimate an orthological value of the strength reduction factor q of the European seismic code based on a target performance level is presented. Several parameters that affect the elastic and inelastic response of the planar steel moment resisting frames are taking into account. The simple bilinear hysteretic rule is been used to model the inelastic response of the members by including the degradation of their strength. The comparison of the inelastic response of the structures with and without degradation of strength is showed. Examples are evaluating the efficiency of the chosen strength reduction factor and they are demonstrating the dominant role of the second order effects that restrict the seismic design of steel moment resisting frames at high performance levels.

Strength Reduction Factor (R-Factor), often referred to as Response Modification Factor, is commonly used in the design of lateral force resisting systems under seismic loading. R-Factors allow for a reduction in design base shear demands, leading to more economical designs. The reduction of strength is remedied with ductile behavior in members of proper detailing. Modern seismic codes and provisions recommend R-Factors for many types of lateral force resisting systems. However these factors are independent of the system fundamental frequency and many other important system properties, resulting in factors that may result in an unfavorable seismic response. To evaluate the validity of prescribed R-Factors an extensive analytical parameter study was conducted using a FEM single degree-of-freedom Concentrically Braced Frame (CBF) under incremental dynamic analysis over a suite of ground motions. Parameters of the study include brace slenderness, fundamental frequency, increment resolution, FEM mesh refinement, effects of leaning columns, and effects of low-cycle fatigue. Results suggest that R-Factor can vary drastically for CBF systems with differing properties.

Liquefaction is one of the major causes of ground failures during an earthquake. Recent evidence shows that the existing variants of the "simplified" liquefaction evaluation procedure lead to inaccurate results for megathrust earthquakes in subduction interfaces. To overcome this drawback and to achieve better prediction of liquefaction cases in subduction zones, this research intends to develop new empirical models that could be used for the prediction of liquefaction triggering in subduction zones. Towards this goal, new models for number of equivalent cycles (n_eq) and stress-reduction factor (r_d) have been proposed. The models are developed by regressing site response data obtained from 254 pairs of subduction ground motions and 77 representative soil profiles. To account for tectonic differences and magnitude scaling, separate models are developed for interface and intraslab earthquakes. The uncertainties involved in the proposed models are quantified through standard deviations of regression coefficients, event, site, and residual terms. The resulting models differ from other published models, especially the model for number of equivalent cycles. It was found that n_eq is greatly influenced by the fundamental site period. The model for r_d predicts higher values at shallow depths and lower values at deeper layers than other published models. Comparing the factors of safety against liquefaction with those from other existing models revealed that the use of models proposed in this research is more likely to reduce the "false positives" in liquefaction predictions, especially when design ground motion acceleration is high. / Master of Science / During earthquake shaking, loose saturated sands may lose strength and behave more like a liquid than a solid. This phenomenon is referred to liquefaction. Liquefaction has been responsible for infrastructure failure during past earthquakes, thus leading to major economic losses. This prompts the prediction and mitigation of potential liquefaction effects in a building site. However, the current state-of-the-practice for predicting liquefaction is inaccurate for large magnitude earthquakes in subduction zones. This provided the impetus for this research which focusses on developing new liquefaction evaluation models for large magnitude earthquakes. New models for number of equivalent cycles and stress reduction factor are developed by analyzing the representative ground motions and soil strata. These empirical parameters are central to the prediction of liquefaction triggering. Comparing the new models with the existing models revealed that the factor of safety against liquefaction estimated using new models are greater than those obtained using existing models for large magnitude earthquake scenario when the ground acceleration is high. This implies that using the existing models for predicting liquefaction in a site subjected to high values of ground acceleration from a subduction earthquake will lead to "false positives." Developed using a comprehensive dataset and robust regression techniques, the models developed in this research will lead to better predictions of liquefaction due to large subduction events.

Dissertation presented for the Degree of Doctor of Philosophy at Stellenbosch University. / Thesis (PhD (Business Management))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Uncertainty of continued donor funding poses a risk to microfinance operations worldwide, and this study explores the circumstances under which African microfinance institutions (MFIs) will consider commercial funding as a viable alternative source of funding. This research aims to identify the factors that are associated with successful access to private capital for pro-poor financial institutions. It examines the suitability of new opportunities for accessing fresh capital by MFIs for development and poverty reduction using commercialisation as an option. In a world awash in private capital, it is vital to harness the power of the private sector to solve key development challenges (World Bank, 2007). As microfinance institutions grow, they increasingly find themselves in need of additional capital to finance expansion of services to cover more poor communities. The study undertook a cross-country data analysis of 103 microfinance institutions to help provide understanding of the critical success factors that underpin successful access to commercial capital. The study also tested the hypothesis on the viability of commercial finances, and developed and tested a commercialisation success model for tapping commercial funds. The prediction model based on firm-level data from a sample of 21 African countries between 1998 and 2003, aims to minimise chances of failure and act as a screening system by investors as well as a selfassessment tool for MFIs intending to seek commercial capital. On examining the direct and indirect impact of firm-level success factors on commercialisation, the study identified key predictors of success and guidelines for MFI financing’s integration with the larger financial system. The study finds that certain critical success factors (CSFs) define minimum pre-conditions for microfinance institutions considering commercial funding as an alternative source of finance. There is evidence to suggest that the desire to tap into the capital markets and capacity to link with commercial investors is a realisable vision for African MFIs. The research evidence is instructive of widened financing options for MFIs and capacity to relax growth constraint in the industry. Based on the CSFs, the study suggests how MFIs can break free from 'captive' donor funding as a necessary platform for the switch to commercial finance in the industry. However, the findings also suggest the need for MFIs to satisfy the interests and requirements of prospective commercial investors to overcome new challenges. In particular, the results show that the extent of organisational formalisation and transparency in financial reporting are absolutely essential in drawing commercial lenders to invest in microfinance. In addition the study establishes the reasons why traditional approaches to financing microfinance cannot work any longer. There are some concerns on mission drift; in particular whether the poor gain from commercialisation, and under what circumstances their interests are taken care of in order to preserve the long-term social value of microfinance as a poverty reduction strategy. The study was carried out based on a rather limited time series data. However, the number of firms and the diversity is considered adequate for the study, as well as sample representation across Africa. The study also used views of 'thought leaders' as the source of information. Other personnel calibre may have had different suggestions. Perceptions were drawn from commercial lenders/investors of microfinance programmes based in Africa. Needless to say, any generalisation of CSFs beyond the African microfinance context should be made with caution. This study is probably one of the first attempts to explore the possibility of a linkage between microfinance and capital markets and it will be of interest to MFIs, commercial banks, international donors and investment funds with an interest in investing in the microfinance industry. The findings suggest that the speed of increase in financial leverage per country depends as much on the dynamism of the market, as it does on the level of development of the finance sector. The results indicate that commercial investors will be attracted by good financial returns and administrative efficiency (return on assets, cash-flow adequacy and operating expense ratio), transparent reporting and information disclosure and clarity, as well as low inflation levels. Investors will also be looking for larger, regulated and profitable MFIs with a low-risk profile for their investment portfolios. The study found strong support to the hypothesis that the commercialisation index (CI) is a better measure of successful commercialisation than the LMA (leverage multiplier added), given the variables used. In all cases, compelling evidence shows that the CI has more explanatory power and is an accurate predictor of two-year success in commercialisation as examined by logistic regression. These results suggest that the superior predictive abilities of the CI commercial rating rule could be explored to guide screening efforts for winners, investment decisions and other binary classification investigations. Specifically, the model can be useful in guiding successful commercialisation schemes in Africa because it provides MFIs with a structured approach for achieving sustainable commercial microfinance. / AFRIKAANSE OPSOMMING: Onsekerheid oor volgehoue skenkerbefondsing is ’n risiko vir mikrofinansieringsinstansies wêreldwyd, en hierdie studie ondersoek die omstandighede waaronder Afrika se mikrofinansieringsinstansies (MFIs) kommersiële befondsing sal oorweeg as ’n lewensvatbare, alternatiewe bron van befondsing. Hierdie navorsing poog om die faktore, wat met die suksesvolle toetrede tot private kapitaal van pro-arm finansiële instellings geassosieer word, te identifiseer. Dit ondersoek die gepastheid van nuwe geleenthede vir MFIs om vars kapitaal te bekom en as ’n opsie te gebruik vir ontwikkeling en die vermindering van armoede deur kommersialisasie. In ’n wêreld met oorvloedige bronne van private kapitaal is dit lewensnoodsaaklik om die krag van die privaatsektor in te span om kern ontwikkelingsuitdagings op te los (World Bank, 2007). Soos mikrofinansieringsinstansies groei, het hulle ’n toenemende behoefte aan addisionele kapitaal ten einde die uitbreiding van dienste te kan finansier en om meer arm gemeenskappe te kan bereik. Die studie het data komende van 103 mikrofinansieringsinstansies uit verskeie lande ontleed om begrip van die kritiese suksesfaktore (KSFe), wat suksesvolle toegang tot kommersiële kapitaal onderskraag, te verkry. Die studie het ook die hipotese oor die lewensvatbaarheid van kommersiële finansiering getoets, en ’n model vir kommersialisasie-sukses ontwikkel en getoets om kommersiële fondse te bekom. Die voorspellingsmodel, wat gebaseer is op maatskappy-vlak data van ’n groep van 21 Afrika lande tussen 1998 en 2003, poog om die kanse op mislukking te minimeer en te dien as ’n siftingstelsel vir beleggers sowel as ’n selfondersoekmiddel vir MFIs wat beplan om kommersiële kapitaal te bekom. Deur die direkte en indirekte impak van maatskappyvlak suksesfaktore op kommersialisasie te bestudeer, het die studie sleutelvoorspellers van sukses asook riglyne vir die integrasie van MFI finansiering met die groter finansiële stelsel geïdentifiseer. Die studie bevind dat sekere KSFe minimum voorvereistes vaslê vir MFIs wat kommersiële befondsing as ’n alternatiewe bron van finansiering oorweeg. Daar is bewyse wat daarop dui dat die begeerte om toegang tot die kapitaalmarkte te verkry en die kapasiteit om met kommersiële beleggers te skakel ’n realiseerbare visie vir Afrika MFIs is. Die navorsing lewer insig wat aanduidend is van breër finansieringsopsies vir MFIs, en wat die beperkinge op groei in die industrie verslap. Gebaseer op die KSFe, stel die studie voor hoe MFIs uit die houvas van skenkerbefondsing kan loskom as ’n nodige stap vir die oorskakeling na kommersiële finansiering in die bedryf. Die bevindings dui egter ook op die behoefte van MFIs om aan die belange en vereistes van moontlike kommersiële beleggers te voldoen ten einde nuwe uitdagings te oorkom. Die resultate dui spesifiek daarop dat die mate van organisasie-formalisering en die deursigtigheid van finansiële verslagdoening noodsaaklik is om kommersiële uitleners te trek om in mikrofinansiering te belê. Verder bevestig die studie die redes waarom tradisionele benaderings tot die finansiering van mikrofinansiering nie meer kan werk nie. Daar is wel sekere bekommernisse oor die moontlike kompromittering van missie; in besonder is die vraag of die armes wel baat vind by kommersialisasie, en onder watter omstandighede daar na hulle belange omgesien word ten einde die langtermyn sosiale waarde van mikrofinansiering as ’n strategie vir armoede verligting te behou. Die studie is uitgevoer gegrond op tydreeksdata wat betreklik beperk is. Die aantal maatskappye en die diversiteit word egter as voldoende beskou vir die studie, asook dat die steekproef verteenwoordigendend was van lande regoor Afrika. Die studie gebruik ook die menings van ‘leierdenkers’ as ’n bron van inligting. Personeel van ’n ander kaliber mag verskillende voorstelle gehad het. Persepsies is verkry van kommersiële uitleners/beleggers van mikrofinansieringsprogramme wat in Afrika gebaseer is. Vanselfsprekend behoort enige veralgemening van die KSFe buite die Afrika mikrofinansieringskonteks met omsigtigheid gedoen word. Hierdie studie is waarskynlik een van die eerste pogings om die moontlikheid van ’n skakel tussen mikrofinansiering en die kapitaalmarkte te ondersoek en dit sal van waarde wees vir MFIs, kommersiële banke, internasionale skenkers en beleggingsfondse wat in belegging in die mikrofinansieringsbedryf belangstel. Die bevindinge dui daarop dat die spoed waarmee die effek van finansiële hefboom in ‘n land toeneem net soveel afhang van die dinamika van die mark as van die ontwikkelingsvlak van die finansiële sektor. Die bevindinge dui daarop dat kommersiële beleggers aangetrek sal word deur goeie finansiële opbrengste, administratiewe doeltreffendheid (opbrengs op bates, voldoende kontantvloei en die bedryfsuitgawe verhouding), deursigtige verslagdoening en duidelike openbaarmaking van inligting, sowel as lae inflasievlakke. Beleggers gee ook voorkeur aan groter, gereguleerde en winsgewende MFIs met ’n lae risikoprofiel vir hulle beleggingsportefeuljes. Die studie vind sterk ondersteuning vir die hipotese dat die Kommersialisasie-indeks (CI) ’n beter aanduiding van suksesvolle kommersialisasie is as die Leverage Multiplier Added (LMA), gegewe die veranderlikes wat gebruik is. In alle gevalle was daar sterk getuienis dat die CI ’n beter verduideliker is en ’n akkurate voorspeller is van die tweejaartermyn sukses in kommersialisasie soos deur middel van logistiese regressie getoets. Hierdie resultate dui daarop dat die superieure voorspellingsvermoëns van die CI se kommersiële beoordelingsreëls beproef kan word om die sifting van wenners, beleggingsbesluite en ander binêre klassifikasie ondersoeke te lei. Die model kan spesifiek nuttig wees om rigting te gee aan suksesvolle kommersialisasieskemas in Afrika omdat dit MFIs ’n gestruktureerde benadering gee tot die bereiking van volhoubare kommersiële mikrofinansiering.