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Robust coalition formation in a dynamic, contractless environmentJones, Christopher Lyman 21 June 2010 (has links)
This dissertation focuses on robust coalition formation between selfish agents in a dynamic environment where contracts are unenforceable. Previous research on this topic has covered each different aspect of this problem, but no research successfully addresses these factors in combination. Therefore, a novel approach is required. This dissertation accordingly has three major goals: to develop a theoretical framework that describes how selfish agents should select jobs and partners in a dynamic, contractless environment, to test a strategy based on that framework against existing heuristics in a simulated environment, and to create a learning agent capable of optimally adjusting its coalition formation strategy based on the level of dynamic change found in its environment. Experimental results demonstrate that the Expected Utility (EU) strategy based on the developed theoretical framework performs better than strategies using heuristics to select jobs and partners, and strategies which simulate a centralized “manager”. Future work in this area includes altering the EU strategy from an anytime strategy to a hill-climbing one, as well as further game theoretic explorations of the interactions between different strategies. / text
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Active learning in cost-sensitive environmentsLiu, Alexander Yun-chung 21 June 2010 (has links)
Active learning techniques aim to reduce the amount of labeled data required for a supervised learner to achieve a certain level of performance. This can be very useful in domains where unlabeled data is easy to obtain but labelling data is costly. In this dissertation, I introduce methods of creating computationally efficient active learning techniques that handle different misclassification costs, different evaluation metrics, and different label acquisition costs. This is accomplished in part by developing techniques from utility-based data mining typically not studied in conjunction with active learning. I first address supervised learning problems where labeled data may be scarce, especially for one particular class. I revisit claims about resampling, a particularly popular approach to handling imbalanced data, and cost-sensitive learning. The presented research shows that while resampling and cost-sensitive learning can be equivalent in some cases, the two approaches are not identical. This work on resampling and cost-sensitive learning motivates a need for active learners that can handle different misclassification costs. After presenting a cost-sensitive active learning algorithm, I show that this algorithm can be combined with a proposed framework for analyzing evaluation metrics in order to create an active learning approach that can optimize any evaluation metric that can be expressed as a function of terms in a confusion matrix. Finally, I address methods for active learning in terms of different utility costs incurred when labeling different types of points, particularly when label acquisition costs are spatially driven. / text
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Cairo ecologies : water in social and material cyclesFarmer, Tessa Rose 17 July 2014 (has links)
This dissertation investigates the ways in which the natural and the social overlap in the symbolic center of human activity, cities. Cities are full of living organisms, existing not in a perfect state of equilibrium but rather in states of constant flux. The cycles of life moving through the city of Cairo, Egypt are dependent on water as a vital component and scarce resource in systems of biological exchange, as well as one among many pieces of infrastructure that the city requires to survive. This dissertation looks at the informal systems that residents of a squatter settlement in Cairo, Egypt called Ezbet Khairallah have created to make life possible, as well as their attempts to get the state to formally provide these services; work that is done at collective scales and in everyday practices. The dissertation also looks at what happens when areas such as Ezba are successful in getting the state to recognize them and institutionalize utility services, what the hidden costs and unintended consequences are of becoming formal end users of state systems. The dissertation provides an overview of the forces at work in shaping Cairo, highlighting the rural to urban migration patterns and shifting urban policy over the course of the 20th century that have funneled so many into informal housing settlements. In addition, the dissertation highlights the particular material history of Ezbet Khairallah, and how that has shaped the social and material circumstances of residents. It examines the material and affective implications of being unable to escape waste, of bodies that bear signs of systems that both make life possible and make life difficult. By studying the institutional framework in which these questions get worked out in Egypt, we can better situate the struggles of those living in the urban margins of the global south, such as those in Ezbet Khairallah. / text
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Hållbarhetsredovisning enligt GRI:s riktlinjer : En studie av två svenska statliga företagYtterberg, Cecilia, Broman, Maria January 2014 (has links)
No description available.
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Estimation and optimal designs for multi-response Emax modelsMagnúsdóttir, Bergrún Tinna January 2014 (has links)
This thesis concerns optimal designs and estimation approaches for a class of nonlinear dose response models, namely multi-response Emax models. These models describe the relationship between the dose of a drug and two or more efficacy and/or safety variables. In order to obtain precise parameter estimates it is important to choose efficient estimation approaches and to use optimal designs to control the level of the doses administered to the patients in the study. We provide some optimal designs that are efficient for estimating the parameters, a subset of the parameters, and a function of the parameters in multi-response Emax models. The function of interest is an estimate of the best dose to administer to a group of patients. More specifically the dose that maximizes the Clinical Utility Index (CUI) which assesses the net benefit of a drug taking both effects and side-effects into account. The designs derived in this thesis are locally optimal, that is they depend upon the true parameter values. An important part of this thesis is to study how sensitive the optimal designs are to misspecification of prior parameter values. For multi-response Emax models it is possible to derive maximum likelihood (ML) estimates separately for the parameters in each dose response relation. However, ML estimation can also be carried out simultaneously for all response profiles by making use of dependencies between the profiles (system estimation). In this thesis we compare the performance of these two approaches by using a simulation study where a bivariate Emax model is fitted and by fitting a four dimensional Emax model to real dose response data. The results are that system estimation can substantially increase the precision of parameter estimates, especially when the correlation between response profiles is strong or when the study has not been designed in an efficient way. / <p>At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 1: Manuscript; Paper 2: Manuscript; Paper 3: Manuscript; Paper 4: Manuscript.</p>
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Increasing the resilience of urban water utilities to extreme weather eventsEzeji, Joachim Ibeziako January 2013 (has links)
The sustainability of municipal drinking water services in the Niger Delta region of Nigeria requires that its water utilities enhance their resilience to a range of risks posed by extreme weather events. Excellence in managing such risks is essential, not only to the bottom line and reputation of the utilities, but also to the wellbeing and prosperity of the people they serve and the preservation of nature in order to sustain ecosystem services. In the context of this study, organisational resilience has been defined as the adaptive deployment of the utility s assets and structures within its continua of inter-dependences to improve and sustain performance even in the face of repeated perturbations. On the other hand, vulnerability is defined as the utility s inability to withstand adverse stress based on limited or constrained capacity to adapt hence creating pathways through which risk impacts the utility. This definition of vulnerability is in tandem with those that argue that the key parameters of vulnerability are the stress to which a system is exposed, its sensitivity, and its adaptive capacity. In view of this, and also based on the findings of the study, the study notes that utility management could be a complex and challenging task, especially, in a multi-risk delta environment where extreme events are intense and frequent. Utility managers can become veterans of risks by dissipating, more than ever before technical competence, watershed/ecosystem awareness, social engagement skills and conceptual ability. The latter includes an understanding of how the complexities of the upstream and downstream environment impacts on the utility s internal environment and operations. The diffusive nature of risk makes every risk a potential high impact risk and the understanding of this, is the key to a resilient organization. Risk analysis and management in water utilities should aim to limit the diffusion of risks across streams in order to retard vulnerability. Utility resilience options will need to vary depending on climate related risks to each system, utility management goals, legislation, local and national water management strategies and finance. Utilities in the Niger delta needs to fully understand that they operate close to the edge by virtue of being below sea level and should cultivate a keen awareness of the consequences of flooding and saltwater intrusion, and the importance to manage them amongst others. The study has shown that there is need now, more than ever before for increased revenue generation, elimination of wastes/inefficiencies, financial investment and strategic management of water services operations in the study area if residents and the unborn generation are to be guaranteed of safe and adequate drinking water.
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Acceptance Tests – FAT & SAT : An Empirical Case Study of Utility PolesAl Farra, Hussni January 2016 (has links)
The overall purpose of this project is to devise improved quality acceptance procedures to examine quality characteristics of utility poles at the factory of the supplier (FAT) and on-site upon receipt by the customer (SAT). To that end, the thesis draws upon available standards, literature, and industry practices regarding wood, fiberglass and steel poles. As far as the design of the research, a single case study of a major power company was chosen. Then, a data collection plan was developed in order to build upon the existing knowledge found in the literature, and upon the data that can be collected from three of the Company’s suppliers, in addition to the Technical Research Institute of Sweden (SP). Documents’ analysis, interviews, observations, and a survey were the tools of that plan. It was found that criteria, inspection and test methods of wood poles are all sufficiently covered in the standards and the literature; for wood is the most commonly used material for utility poles. Next, in coverage of research, are the steel poles; while there is currently no standard that covers fiberglass utility poles. Indeed, quality characteristics, criteria, and acceptance procedures can altogether form parts of a sustainable solution, as long as the quality is managed as a process whether at the Company’s end or at the fabrication sites; that is especially true if there is some form of backward partnership between the Company and its suppliers.
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The Brier Rule Is not a Good Measure of Epistemic Utility (and Other Useful Facts about Epistemic Betterness)Fallis, Don, Lewis, Peter J. 14 December 2015 (has links)
Measures of epistemic utility are used by formal epistemologists to make determinations of epistemic betterness among cognitive states. The Brier rule is the most popular choice (by far) among formal epistemologists for such a measure. In this paper, however, we show that the Brier rule is sometimes seriously wrong about whether one cognitive state is epistemically better than another. In particular, there are cases where an agent gets evidence that definitively eliminates a false hypothesis (and the probabilities assigned to the other hypotheses stay in the same ratios), but where the Brier rule says that things have become epistemically worse. Along the way to this 'elimination experiment' counter-example to the Brier rule as a measure of epistemic utility, we identify several useful monotonicity principles for epistemic betterness. We also reply to several potential objections to this counter-example.
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Värdering av personburna soldatigenkänningssystem, så kallade Combat Identification Systems (CID), avsedda att förebygga vådabekämpning i urban miljöÖqvist, Anders January 2016 (has links)
För att känna igen eller identifiera egna förband och enheter har man sedan långt tillbaka använt sig av olika metoder. Oftast har dessa utgjorts av olika symboler och tecken på fanor, flaggor, uniformer med mera. I nutid har allt fler olika tekniska system för igenkänning och identifiering, eller så kallad Combat Identification (CID), av egna förband, börjat användas. Dessa system uppvisar mer eller mindre komplexitet, har olika för- respektive nackdelar och bidrar i olika utsträckning till förmågan att framgångsrikt genomföra CID. Syftet med uppsatsen är att jämföra olika CID-system konstruerade för avsutten trupp för att öka kunskapen avseende den militära nytta systemen har med avseende på minskad risk för vådabekämpning när ett förband sätts in i urban miljö. Vid jämförelsen av de olika systemen kan konstateras att CID-systemen endast ger militär nytta när ett förband har en uppgift där stridsförloppen är långsamma, till exempel övervakning. De CID-system som särskilt utmärker sig vid övervakning är TIR-systemen. / Since long ago different methods have been used in order to recognize or identify own units. Most often the methods consisted of different symbols and signs placed on banners, flags, uniforms and so on. Today several different technical systems for recognition and identification of own units, so called Combat Identification (CID), are entering service. The systems show more or less complexity in their construction, hold advantages as well as disadvantages and thus contribute in varying degree to the ability to successfully carry out CID. The purpose of this essay is to compare different CID-systems designed for ground soldiers, in order to increase the knowledge of what military utility the different systems may have in terms of reducing the risk of friendly fire when a unit is deployed in an urban environment. When comparing the different systems it is clearly that CID-systems only give military utility when a unit has a task where the battle progress is slow, such as surveillance. The CID-system that especially excels when used in surveillance is the TIR-systems.
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Parent Preferences for Baby Formula in China and Potential Implications for U.S. Dairy Product ExportsCui, Hao 01 January 2016 (has links)
As the world's most populous country, with more than 16 million births every year, China has emerged as a large importer of baby formula. China's relaxation of the one-child policy, which was announced in 2015, is expected to increase the number of births significantly and therefore increase the demand for Chinese and imported baby formula. While information on parent preferences for baby formula is very important for understanding and predicting China's import demand for baby formula and other products used to produce baby formula, like milk powder, there are very limited empirical studies on Chinese parent preferences for baby formula in the literature due to data limitation and other reasons. This research collects primary data from China through a parent survey, uses the data to analyze parent preferences and willingness to pay (WTP) for selected baby formula attributes, and derives implications for U.S. dairy product exports. Specifically, with detailed data from a total of 433 respondents, this study first examines parent purchase behavior of baby formula through descriptive analysis, then assesses parent preferences and WTP for selected baby formula attributes through the estimation of a random utility model, and finally derives implications for U.S. exports of milk powder, whey, and other dairy products.
The descriptive analysis suggests that education level and income play an important role in parent purchase behavior of baby formula. The estimation results of the random utility model differed according to whether the survey was administered online or as a hardcopy. The results from the online survey indicate that imported, organic, and more reputable brands of baby formula are more attractive to respondents than domestic, non-organic, and less reputable brands. While respondents who completed the hardcopy survey also indicated a preference for organic baby formula from a reputable brand, they preferred domestic baby formula to imported formula. Further analysis of the WTP from the online survey for baby formula showed that parents have a strong preference and are willing to pay significantly more for baby formulas produced in Australia and the U.S. as compared to that produced in China. They are willing to pay more for organic baby formula and baby formula with an excellent reputation. The WTP results from the hardcopy survey indicate that parents are willing to pay more for domestic baby formula. They are also willing to pay more for organic baby formula and baby formula with an excellent reputation. China's emerging demand for imported baby formula, milk powder, and whey may bring more opportunities for the U.S. dairy industry, but U.S. dairy products are also facing increasing competition from similar products from other nations in the Chinese market. More studies are needed to identify the comparative advantages of U.S. baby formula and other dairy products in the Chinese market and to develop effective trade policies for enhancing U.S. exports to China.
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