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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Structure determination of ribosomal proteins and development of new methods in biomolecular NMR

Helgstrand, Magnus January 2001 (has links)
<p>This thesis concerns different areas of biomolecular nuclearmagnetic resonance spectroscopy (NMR). In the first part of thethesis a new formalism for simulations of NMR pulse sequencesis introduced. The formalism is derived both from classicalmechanics and quantum mechanics and is presented forhomonuclear and heteronuclear spin systems. The formalism hasalso been adapted to systems in chemical exchange. Simulationsof pulse sequences should be more straightforward using the newformalism.</p><p>In the second part of the thesis the NMR solution structuresof two ribosomal proteins are described. The ribosome isresponsible for protein production in all living cells and tounderstand the mechanism of the ribosome it is important toknow the three dimensional structure. In this thesis thestructures of S16 and S19, two of the proteins in the smallribosomal subunit, are presented. S16 is a mixed α /βprotein with a five-stranded parallel-antiparallel β-sheetand two α -helices. S19 is s mixed α/β proteinwith a three-stranded parallel-antiparallel β -sheet, oneα -helix and a short 3<sub>10</sub>-helix.</p><p>In the third part of the thesis a program for semiautomaticassignment of NMR-spectra is presented. Assigning resonances inthe NMR spectrum is a labor-intensive process, which can takelong time. In semiautomatic assignment a computer program aidsthe user in finding assignments but leaves all decisions to theuser, thus speeding up the process. The program described inthis thesis is a new version of ANSIG, called Ansig forWindows. The program runs on PCs under Windows and has severaltools for semiautomatic assignment.</p><p><b>Keywords:</b>nuclear magnetic resonance, structuredetermination, ribosomal proteins, NMR simulations, NMR theory,NMR assignment software, semiautomatic assignment</p>
72

Capacitated Schedule-Based Transit Assignment Using a Capacity Penalty Cost

Noh, Hyunsoo January 2013 (has links)
Schedule-based transit assignment models have been studied extensively from 2000, considering more time-dependent transit passenger behavior associated with the transit schedule. Currently, transit schedule information is more easily accessed using new telecommunications systems, such as mobile devices and the internet. One critical example of information sharing is Google's General Transit Feed Specification (GTFS). The information of the schedule per se, however, is not enough to explain the transit passenger's behavior, especially in a congested transit system. Regarding the congestion issues on a transit system, numerous researches have studied a transit schedule network (Nguyen et al., 2001; Nuzzolo et al., 2001; Poon et al., 2004; Hamdouch and Lawphonpanich, 2008, 2010).Along the stream toward understanding transit passenger behavior in the capacitated transit schedule network, we propose solution models for solving the deterministic and stochastic user equilibrium (SUE) problems on a capacitated transit schedule network. Nguyen et al. (2001) introduced how the capacitated user equilibrium (UE) on a transit schedule network is different from the auto user equilibrium. For the foundation of the study, we utilize the link-based and time-expanded (LBTE) transit schedule network introduced by Noh et al. (2012a) which effectively captures turning movements like transfers easily as well as maintaining the efficient size of a schedule-based network. In the LBTE transit network, time points are assigned to each link connecting two stops by each run (or route). Utilizing the "link-based" structure, a link-based shortest path (LBSP) and hyperpath search (LBHP) models (Noh et al., 2012a) are introduced. Especially, the hyperpath employs a log-sum weighting function for incorporating multiple schedule alternatives at each stop node considering passenger's stochastic behavior. One distinctive transit passenger behavior over a congested transit system is a first-in-first-out (FIFO) priority on boarding. A passenger already on board has the higher priority than passengers who are about to boarding, and the passengers arriving earlier at a stop will have higher priority than the passengers arriving later at the stop. To consider the capacitated UE considering the relation between the FIFO boarding priority and vehicle capacity constraint, we apply a "soft-capacity" cost (Nguyen et al., 2001). This soft capacity cost function allows some violation of the predefined vehicle capacity, but the violation will be penalized and affect the cost of the path in the next iteration. The penalty of the soft capacity cost function allows not to assigning passengers on the alternatives having the lower priority of boarding, which finally leads to the solution of the capacitated transit deterministic user equilibrium (DUE) or SUE problems. For the main transit assignment models, we proposed path- and hyperpath-based methods and a self-adaptive method considering deterministic and stochastic passenger behaviors. First, we developed the hyperpath-based assignment method by Noh et al. (2012b). For the FIFO transit passenger behavior, typically accompanying asymmetric (non-separable) cost relation, we also introduce a diagonalization technique (Sheffi, 1985) with the method of successive average (MSA) assignment technique. As expecting a better performance, second, we introduced the path-based assignment models using gradient projection. For the FIFO passenger behavior on boarding, we considered the same diagonalization approach used in the hyperpath-based assignment model and a full-Hessian scaling matrix in the gradient projection. By utilizing a full path set for each O-D pair, a better performance is guaranteed with the path-based model but the diagonalization technique may result in longer iterations. For improving the diagonalization steps, third, we explored several other possible methods. Above all, we proposed the better initial solution (BIS) model which assigns the initial flows on the priority path over congested links and also maintains feasible flows below the capacity constraint. On the other hand, we also added two additional assignment models to improve the diagonalization technique. One utilizes a full Hessian scaling matrix in the proposed path-based assignment model instead of diagonalization and the other is the self-adaptive gradient projection (SAGP) model introduced by Chen et al. (2012) which does not require a scaling matrix by optimizing the step-size in the path-based projection model. For improving the SAGP model, we modified the SAGP model. First, we applied the SAGP at a disaggregate level for each O-D pair as expecting a compact set of path alternatives limited by each O-D pair, called disaggregate self-adaptive gradient projection (DSAGP). Second, we applied a type of diagonalization technique in the SAGP model by maintaining the residual capacities for the estimated flows in the next iteration. Beyond just a single model development, the proposed transit assignment models not only showed various possibilities of the transit assignment, but also showed which model is more efficient and practical in terms of a real application. A computational model structure using the proposed models was mainly designed for an effective model development by sharing numerous components as well as maintaining the efficient data structure. The nine combination models based on the proposed three main models (hyperpath- and path-based and DSAGP assignment models) and the efficient BIS technique for solving the problems were tested and analyzed on a sample network and a partial Sacramento regional transit network.
73

The pactum de non cedendo :a re-evaluation

Kelly Dawn Sunkel January 2009 (has links)
<p>Since the pactum de non cedendo is prohibitory by its nature and operation, our law should have proceeded with caution when determining its effect. This, unfortunately, is not what transpired in the locus classicus decision. Nor did subsequent cases correct this fatal ratio. The distressing truth is that the old authorities, upon whom the locus classicus judgment is based, were in all probability not writing about pacta de non cedendo. Strangely enough, when this was suggested by an academic in the field, it elicited no response. The lack of response evidences a lack of interest in the topic in general, partly due to the uncertain state of affairs in which the pactum de non cedendo operates, and partly due to the courts&rsquo / unwillingness to rectify the situation. Despite the waning interest, the pactum de non cedendo is prevalent and appears in many types of contracts, most recently in the powerhouse factoring industry, and cannot simply be swept under the rug. This dissertation breathes new life into the pactum de non cedendo and discusses its validity and effect from a fresh perspective: A commercial perspective with a strong influence from American law. Hopefully this re-evaluation of the pactum de non cedendo will re-capture the attention of academics and judges alike, so that those in the position to do so, will re-consider its validity and effect.</p>
74

Advanced Methodologies in Dynamic Traffic Assignment Modeling of Managed Lanes

Shabanian, Shaghayegh 06 May 2014 (has links)
Managed lane strategies are innovative road operation schemes for addressing congestion problems. These strategies operate a lane (lanes) adjacent to a freeway that provides congestion-free trips to eligible users, such as transit or toll-payers. To ensure the successful implementation of managed lanes, the demand on these lanes need to be accurately estimated. Among different approaches for predicting this demand, the four-step demand forecasting process is most common. Managed lane demand is usually estimated at the assignment step. Therefore, the key to reliably estimating the demand is the utilization of effective assignment modeling processes. Managed lanes are particularly effective when the road is functioning at near-capacity. Therefore, capturing variations in demand and network attributes and performance is crucial for their modeling, monitoring and operation. As a result, traditional modeling approaches, such as those used in static traffic assignment of demand forecasting models, fail to correctly predict the managed lane demand and the associated system performance. The present study demonstrates the power of the more advanced modeling approach of dynamic traffic assignment (DTA), as well as the shortcomings of conventional approaches, when used to model managed lanes in congested environments. In addition, the study develops processes to support an effective utilization of DTA to model managed lane operations. Static and dynamic traffic assignments consist of demand, network, and route choice model components that need to be calibrated. These components interact with each other, and an iterative method for calibrating them is needed. In this study, an effective standalone framework that combines static demand estimation and dynamic traffic assignment has been developed to replicate real-world traffic conditions. With advances in traffic surveillance technologies collecting, archiving, and analyzing traffic data is becoming more accessible and affordable. The present study shows how data from multiple sources can be integrated, validated, and best used in different stages of modeling and calibration of managed lanes. Extensive and careful processing of demand, traffic, and toll data, as well as proper definition of performance measures, result in a calibrated and stable model, which closely replicates real-world congestion patterns, and can reasonably respond to perturbations in network and demand properties.
75

Stochastic local search algorithms for single and bi-objective quadratic assignment problems

Bin Hussin, Mohamed Saifullah 17 December 2015 (has links)
The study of Stochastic Local Search (SLS) algorithms is becoming more pivotal these days, due to their vast number of applications in decision making. Prior to the implementation of algorithmic knowledge for decision making, many decisions were made based on manual calculation, on the fly, or even based on guts feeling. Nowadays, such an approach is more rarely seen, especially when the decisions that need to be made are high-risk, cost intensive, or time-consuming. The increasingly often used SLS algorithms are one of the options available to assist the decision making process these days.The work discussed in this thesis concerns the study of SLS algorithms for solving the Quadratic Assignment Problem (QAP), a prominent combinatorial optimization problem, which until today is very hard to solve. Our interest is to study the behavior and performance of SLS algorithms for solving QAP instances of different characteristics, such as size, sparsity, and structure. In this study, we have also proposed new variants of SLS algorithms, inspired by existing, well-performing SLS algorithms for solving the QAP. The new variants of SLS algorithms are then further extended for solving the bi-objective QAP (bQAP).One main focus in this study is to see how the performance of algorithms scales with instance size. We have considered instances that are much larger than the ones usually used in the studies of algorithms for solving the QAP. By understanding how the algorithms perform when the instance size changes, we might be able to solve other problems effectively by considering the similarity in their characteristics to the ones of the QAP, or by seeing common trends in the relative performance of the various available SLS methods. For single objective QAP instances we found that the structure and size of instances do have a significant impact on the performance of SLS algorithms. For example, comparisons between Tabu Search (TS) and Simulated Annealing (SA) on instances with randomly generated matrices show that the overall performance of TS is better than SA, irrespective the size of instances considered. The results on a class of structured instances however show that TS performs well on small-sized instances, while on the larger ones, SA shows better results. In another experiment, Hierarchical Iterated Local Search (HILS) has shown very good results compared to several Iterated Local Search (ILS) variants. This experiment was done on a class of structured instances of size from 100 to 500. An extensive experiment on a class of structured instances of size 30 to 300 using tuned parameter settings shows that population based algorithms perform very well on most of the instance classes considered. SA however, shows very good performance especially on large-sized instances with low sparsity level. For the bQAP, the correlation between the flow matrices does have a strong effect that determines the performance of algorithms for solving them. Hybrid Simulated Annealing (HSA) clearly outperforms Hybrid Iterative Improvement (HII). When compared to Multi Objective Ant Colony Optimization (MOACO) and Strength Pareto Evolutionary Algorithm 2 (SPEA2), HSA shows very good performance, where HSA outperforms MOACO and SPEA2, especially on instances of large size, thus, offering a better scaling behavior. Based the results obtained in this study, it is possible to come up with a general idea on the suitability of SLS algorithms for solving instances with a certain characteristic. Given an unknown QAP instance, one can guess the most suitable algorithm for solving it depending on the type, size, and sparsity of the instance, while for a bQAP instance the most suitable algorithm can be guessed based on its size and correlation between the flow matrices. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished
76

The pactum de non cedendo :a re-evaluation

Sunkel, Kelly Dawn January 2009 (has links)
Magister Legum - LLM / Since the pactum de non cedendo is prohibitory by its nature and operation, our law should have proceeded with caution when determining its effect. This, unfortunately, is not what transpired in the locus classicus decision. Nor did subsequent cases correct this fatal ratio. The distressing truth is that the old authorities, upon whom the locus classicus judgment is based, were in all probability not writing about pacta de non cedendo. Strangely enough, when this was suggested by an academic in the field, it elicited no response. The lack of response evidences a lack of interest in the topic in general, partly due to the uncertain state of affairs in which the pactum de non cedendo operates, and partly due to the courts' unwillingness to rectify the situation. Despite the waning interest, the pactum de non cedendo is prevalent and appears in many types of contracts, most recently in the powerhouse factoring industry, and cannot simply be swept under the rug. This dissertation breathes new life into the pactum de non cedendo and discusses its validity and effect from a fresh perspective: A commercial perspective with a strong influence from American law. Hopefully this re-evaluation of the pactum de non cedendo will re-capture the attention of academics and judges alike, so that those in the position to do so, will re-consider its validity and effect. / South Africa
77

Přířazovací problém a jeho praktická aplikace v oblasti přepravy osob / Assignment problem and its particular application in passenger transport

Asterová, Jana January 2017 (has links)
This thesis is focused on the topic of assignment problems. The theoretical part presents a summary of the most important previously published findings on linear and quadratic assignment problem. The basic formulations of both problems are introduced, as well as the outline of some methods developed for their solution. Finally both problems are illustrated by practical applications that have appeared in the literature. The practical part gives insight into the issue of assignment of transport orders to drivers in a company and proposes a suitable model that speeds up the process of distributing the orders. The transfers conducted by the company start at the airport and terminate in a hotel in the city centre of Prague or vice versa. When proposing order schedules for the drivers, it is necessary to take into account not only the time of the transfers, but additionally the capacity and the category of the vehicle.
78

The mechanics of assignments : functions and form

Tham, Chee Ho January 2016 (has links)
Choses in action are valuable assets. This has compelled (and been facilitated by) the development of legal devices such as equitable assignment to allow holders of choses to deal with them, inter vivos. This thesis makes two claims. First, equitable assignments are best conceived as a composite of a bare trust and an atypical agency where the assignee is authorised to invoke the assignor's entitlements against the obligor to the chose assigned, as the assignee pleases. On this conception, equitable assignments merely entail generation of a new set of jural relations as between assignor and assignee. Though these affect how the jural relations between assignor and obligor are to be discharged, those jural relations are left intact and unchanged, unless the requirements for 'statutory' assignments have been satisfied. Second, 'statutory' assignments are regulatory in effect. Where a debt or other chose in action has been validly equitably assigned and the requirements in s 136(1) Law of Property Act 1925 are satisfied, the specific entitlements set out in sections 136(1)(a), (b) and (c) will be passed from the assignor and transferred to the assignee. But that is only true with regards entitlements falling within those provisions, and the set of entitlements listed therein is not exhaustive. The composite model of equitable assignment, and the clarification of the nature of 'statutory' assignment, reduces confusion over their operation and effects. Accordingly, this thesis tempers the urge towards legislative reform of the law of assignment: reform may not be needed since the law is not incoherent, though it is certainly complex. And if targeted law reform to simplify the law on assignment be thought desirable, it is as well to know what one is reforming.
79

Dynamic Frequency Assignment and Management Technologies for Future Test and Evaluation Operations

Painter, Michael K., Fernandes, Ronald, Gohlke, Jason, Ramachandran, Satheesh, Verma, Ajay, Jones, Charles H. 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / There is growing concern that the U.S. military can no longer meet its domestic and international spectrum needs. Demand for this resource is growing at an exponential pace, both within the Department of Defense (DoD) and in the commercial sector (partly due to rapid growth in broadband wireless electronics). A microcosm of these challenges is evident in flight test operations, where there is a growing need for advanced spectrum assignment, frequency deconfliction, and scheduling optimization decision support capabilities. This paper describes research aimed at investigating how to optimize frequency scheduling, dynamic assignment, and real-time metrics adjustment to promote assured access to the electronic spectrum, including emerging technology developments to support that need.
80

Dilemman kring fritidslärarens uppdrag i skolan

Beata, Kudela, Kourosh, Safinia January 2016 (has links)
Our aim with this essay is to examine the challenges that recreation teachers faces at their workplaces. We especially focus which cause difficulties for the implementation of recreation teacher’s assignments. We hope to highlight the difficulties and factors which act as a barrier to recreation teachers. The questions that we are trying to answer are: what perceptions in their daily work recreation teachers shave of their mission? What challenges do recreation teachers experience in the implementation of their mission? What solutions and aids do recreation teachers use to meet these challenges? We will use a qualitative method in our essay. Data collection includes interviews with four recreation teachers in three different schools. The empirical material will be analyzed and interpreted from a socio- cultural perspective and by means of other research in this area. The result shows that recreation teachers are experiencing challenges but are trying to carry out their mission through a variety of methods in order to provide children with basic care.

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