952 resultados para reasoning about loops


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In many real world situations, we make decisions in the presence of multiple, often conflicting and non-commensurate objectives. The process of optimizing systematically and simultaneously over a set of objective functions is known as multi-objective optimization. In multi-objective optimization, we have a (possibly exponentially large) set of decisions and each decision has a set of alternatives. Each alternative depends on the state of the world, and is evaluated with respect to a number of criteria. In this thesis, we consider the decision making problems in two scenarios. In the first scenario, the current state of the world, under which the decisions are to be made, is known in advance. In the second scenario, the current state of the world is unknown at the time of making decisions. For decision making under certainty, we consider the framework of multiobjective constraint optimization and focus on extending the algorithms to solve these models to the case where there are additional trade-offs. We focus especially on branch-and-bound algorithms that use a mini-buckets algorithm for generating the upper bound at each node of the search tree (in the context of maximizing values of objectives). Since the size of the guiding upper bound sets can become very large during the search, we introduce efficient methods for reducing these sets, yet still maintaining the upper bound property. We define a formalism for imprecise trade-offs, which allows the decision maker during the elicitation stage, to specify a preference for one multi-objective utility vector over another, and use such preferences to infer other preferences. The induced preference relation then is used to eliminate the dominated utility vectors during the computation. For testing the dominance between multi-objective utility vectors, we present three different approaches. The first is based on a linear programming approach, the second is by use of distance-based algorithm (which uses a measure of the distance between a point and a convex cone); the third approach makes use of a matrix multiplication, which results in much faster dominance checks with respect to the preference relation induced by the trade-offs. Furthermore, we show that our trade-offs approach, which is based on a preference inference technique, can also be given an alternative semantics based on the well known Multi-Attribute Utility Theory. Our comprehensive experimental results on common multi-objective constraint optimization benchmarks demonstrate that the proposed enhancements allow the algorithms to scale up to much larger problems than before. For decision making problems under uncertainty, we describe multi-objective influence diagrams, based on a set of p objectives, where utility values are vectors in Rp, and are typically only partially ordered. These can be solved by a variable elimination algorithm, leading to a set of maximal values of expected utility. If the Pareto ordering is used this set can often be prohibitively large. We consider approximate representations of the Pareto set based on ϵ-coverings, allowing much larger problems to be solved. In addition, we define a method for incorporating user trade-offs, which also greatly improves the efficiency.

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The aging population in many countries brings into focus rising healthcare costs and pressure on conventional healthcare services. Pervasive healthcare has emerged as a viable solution capable of providing a technology-driven approach to alleviate such problems by allowing healthcare to move from the hospital-centred care to self-care, mobile care, and at-home care. The state-of-the-art studies in this field, however, lack a systematic approach for providing comprehensive pervasive healthcare solutions from data collection to data interpretation and from data analysis to data delivery. In this thesis we introduce a Context-aware Real-time Assistant (CARA) architecture that integrates novel approaches with state-of-the-art technology solutions to provide a full-scale pervasive healthcare solution with the emphasis on context awareness to help maintaining the well-being of elderly people. CARA collects information about and around the individual in a home environment, and enables accurately recognition and continuously monitoring activities of daily living. It employs an innovative reasoning engine to provide accurate real-time interpretation of the context and current situation assessment. Being mindful of the use of the system for sensitive personal applications, CARA includes several mechanisms to make the sophisticated intelligent components as transparent and accountable as possible, it also includes a novel cloud-based component for more effective data analysis. To deliver the automated real-time services, CARA supports interactive video and medical sensor based remote consultation. Our proposal has been validated in three application domains that are rich in pervasive contexts and real-time scenarios: (i) Mobile-based Activity Recognition, (ii) Intelligent Healthcare Decision Support Systems and (iii) Home-based Remote Monitoring Systems.

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This article explores contemporary ‘hidden land’ narrative constructs of Máyel Lyáng and Beyul Dremojong in Sikkim, India, as conceived by the Lepcha and the Lhopo, two ‘scheduled tribes’. Lepcha and Lhopo narratives about these hidden lands in Mount Khangchendzonga inform us about their contemporary and historical, indigenous and Buddhist contexts and the interactions between these contexts. Lhopo perspectives on the hidden Beyul Dremojong echo classical Tibetan Buddhist ‘revealed treasure’ guidebooks and exist within the complex and reciprocal relationship between the Lhopo and the land they inhabit; development initiatives are understood to have caused illness and death in the Lhopo community of Tashiding, often referred to as the geographical ‘center’ of Beyul Dremojong. Contemporary Lepcha comprehensions of Máyel Lyáng, described in oral narratives within an ethnic community whose cosmology is intimately connected with Mount Khangchendzonga, today show some influence of Lhopo interpretations of Beyul Dremojong and the treasure texts; they also reflect Lepcha fears about cultural dispersion. Present-day narratives about both hidden lands reference notable political events in modern Sikkimese history (encounters with the British; the Chinese occupation of Tibet).

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This study focuses on those substantial changes that characterize the shift of Vietnam’s macroeconomic structures and evolution of micro-structural interaction over an important period of 1991-2008. The results show that these events are completely distinct in terms of (i) Economic nature; (ii) Scale and depth of changes; (iii) Start and end results; and, (iv) Requirement for macroeconomic decisions. The study rejected a suspicion of similarity between the contagion of the Asian financial crisis in 1997-98 and economic chaos in the first half of 2008 (starting from late 2007). The depth, economic settings of, and interconnection between macro choices and micro decisions have all grown up significantly, partly due to a much deeper level of integration of Vietnam into the world’s economy. On the one hand, this phenomenon gives rise to efficiency of macro level policies because the consideration of micro-structural factors within the framework has definitely become increasingly critical. On the other and, this is a unique opportunity for the macroeconomic mechanism of Vietnam to improve vastly, given the context in which the national economy entered an everchanging period under pressures of globalization and re-integration. The authors hope to also open up paths for further empirical verifications and to stress on the fact that macro policies will have, from now on, to be decided in line with changing micro-settings, which specify a market economy and decide the degree of success of any macroeconomic choices.

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Knowledge sharing typically examines organizational transfer of knowledge, often from headquarters to subsidiaries, from developed country sites to emerging country sites, or from host to local employees. Yes, recent research, such as Prahalad’s Bottom of the Pyramid, raises the question of reverse transfer of knowledge, or whether knowledge could and should be transferred from local sites to home country sites within an organization. As several emerging economies build their capabilities in knowledge, research and development, marketing, and the like, it only makes sense to consider what type of knowledge and how to transfer it in reverse or bi-directional manners. This paper takes one step back in the process. Rather than focusing on what knowledge transfer may make sense within an organization, we consider what types of knowledge are important for foreigners to know at the initial stages of engagement abroad as they consider whether to do business in an emerging country.

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We investigated perceptions among overweight and obese state employees about changes to health insurance that were designed to reduce the scope of health benefits for employees who are obese or who smoke. Before implementation of health benefit plan changes, 658 state employees who were overweight (ie, those with a body mass index [BMI] of 25-29.9) or obese (ie, those with a BMI of > or = 30) enrolled in a weight-loss intervention study were asked about their attitudes and beliefs concerning the new benefit plan changes. Thirty-one percent of employees with a measured BMI of 40 or greater self-reported a BMI of less than 40, suggesting they were unaware that their current BMI would place them in a higher-risk benefit plan. More than half of all respondents reported that the new benefit changes would motivate them to make behavioral changes, but fewer than half felt confident in their ability to make changes. Respondents with a BMI of 40 or greater were more likely than respondents in lower BMI categories to oppose the new changes focused on obesity (P < .001). Current smokers were more likely than former smokers and nonsmokers to oppose the new benefit changes focused on tobacco use (P < .01). Participants represented a sample of employees enrolled in a weight-loss study, limiting generalizability to the larger population of state employees. Benefit plan changes that require employees who are obese and smoke to pay more for health care may motivate some, but not all, individuals to change their behaviors. Since confidence to lose weight was lowest among individuals in the highest BMI categories, more-intense intervention options may be needed to achieve desired health behavior changes.

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Many commentators explain recent transatlantic rifts by pointing to diverging norms, interests and geopolitical preferences. This paper proceeds from the premise that not all situations of conflict are necessarily due to underlying deadlocked preferences. Rather, non-cooperation may be a strategic form of soft balancing. That is, more generally, if they believe that they are being shortchanged in terms of influence and payoffs, weaker states may deliberately reject possible cooperation in the short run to improve their influence vis-à-vis stronger states in the long run. This need not be due to traditional relative gains concern. States merely calculate that their reputation as a weak negotiator will erode future bargaining power and subsequently their future share of absolute gains. Strategic non-cooperation is therefore a rational signal of resolve. This paper develops the concept of strategic non-cooperation as a soft balancing tool and applies it to the Iraq case in 2002-2003. © 2005 Palgrave Macmillan Ltd.

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BACKGROUND: Living related kidney transplantation (LRT) is underutilized, particularly among African Americans. The effectiveness of informational and financial interventions to enhance informed decision-making among African Americans with end stage renal disease (ESRD) and improve rates of LRT is unknown. METHODS/DESIGN: We report the protocol of the Providing Resources to Enhance African American Patients' Readiness to Make Decisions about Kidney Disease (PREPARED) Study, a two-phase study utilizing qualitative and quantitative research methods to design and test the effectiveness of informational (focused on shared decision-making) and financial interventions to overcome barriers to pursuit of LRT among African American patients and their families. Study Phase I involved the evidence-based development of informational materials as well as a financial intervention to enhance African American patients' and families' proficiency in shared decision-making regarding LRT. In Study Phase 2, we are currently conducting a randomized controlled trial in which patients with new-onset ESRD receive 1) usual dialysis care by their nephrologists, 2) the informational intervention (educational video and handbook), or 3) the informational intervention in addition to the option of participating in a live kidney donor financial assistance program. The primary outcome of the randomized controlled trial will include patients' self-reported rates of consideration of LRT (including family discussions of LRT, patient-physician discussions of LRT, and identification of a LRT donor). DISCUSSION: Results from the PREPARED study will provide needed evidence on ways to enhance the decision to pursue LRT among African American patients with ESRD.

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In three related experiments, 250 participants rated properties of their autobiographical memory of a very negative event before and after writing about either their deepest thoughts and emotions of the event or a control topic. Levels of emotional intensity of the event, distress associated with the event, intrusive symptoms, and other phenomenological memory properties decreased over the course of the experiment, but did not differ by writing condition. We argue that the act of answering our extensive questions about a very negative event led to the decrease, thereby masking the effects of expressive writing. To show that the changes could not be explained by the mere passage of time, we replicated our findings in a fourth experiment in which all 208 participants nominated a very negative event, but only half the participants rated properties of their memory in the first session. Implications for reducing the effects of negative autobiographical memories are discussed.

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Data from five laboratories using five different techniques were reanalyzed to measure subjects' knowledge of events that occurred over the past 70 years. Subjects were about 20 years of age, so the measures included events that extended up to 50 years before birth. The functions relating knowledge about the events to age do not decrease precipitously at birth but gradually drop to above-chance levels. Techniques usually used to study retention within the individual can be used to study the persistence of ideas and fashions within an age cohort in a culture.

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BACKGROUND: A hierarchical taxonomy of organisms is a prerequisite for semantic integration of biodiversity data. Ideally, there would be a single, expansive, authoritative taxonomy that includes extinct and extant taxa, information on synonyms and common names, and monophyletic supraspecific taxa that reflect our current understanding of phylogenetic relationships. DESCRIPTION: As a step towards development of such a resource, and to enable large-scale integration of phenotypic data across vertebrates, we created the Vertebrate Taxonomy Ontology (VTO), a semantically defined taxonomic resource derived from the integration of existing taxonomic compilations, and freely distributed under a Creative Commons Zero (CC0) public domain waiver. The VTO includes both extant and extinct vertebrates and currently contains 106,947 taxonomic terms, 22 taxonomic ranks, 104,736 synonyms, and 162,400 cross-references to other taxonomic resources. Key challenges in constructing the VTO included (1) extracting and merging names, synonyms, and identifiers from heterogeneous sources; (2) structuring hierarchies of terms based on evolutionary relationships and the principle of monophyly; and (3) automating this process as much as possible to accommodate updates in source taxonomies. CONCLUSIONS: The VTO is the primary source of taxonomic information used by the Phenoscape Knowledgebase (http://phenoscape.org/), which integrates genetic and evolutionary phenotype data across both model and non-model vertebrates. The VTO is useful for inferring phenotypic changes on the vertebrate tree of life, which enables queries for candidate genes for various episodes in vertebrate evolution.

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An examination of why American Protestant churches have a higher likelihood to support torture

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The global value chain (GVC) concept has gained popularity as a way to analyze the international expansion and geographical fragmentation of contemporary supply chains and value creation and capture therein. It has been used broadly in academic publications that examine a wide range of global industries, and by many of the international organizations concerned with economic development. This note highlights some of the main features of GVC analysis and discusses the relationship between the core concepts of governance and upgrading. The key dynamics of contemporary global supply chains and their implications for global production and trade are illustrated by: (1) the consolidation of global value chains and the new geography of value creation and capture, with an emphasis on China; (2) the key roles of global supermarkets and private standards in agri-food supply chains; and (3) how the recent economic crisis contributes to shifting end markets and the regionalization of value chains. It concludes with a discussion of the future direction of GVC analysis and a potential collaboration with supply chain researchers. © 2012 Institute for Supply Management, Inc.

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Molecular data have converged on a consensus about the genus-level phylogeny of extant platyrrhine monkeys, but for most extinct taxa and certainly for those older than the Pleistocene we must rely upon morphological evidence from fossils. This raises the question as to how well anatomical data mirror molecular phylogenies and how best to deal with discrepancies between the molecular and morphological data as we seek to extend our phylogenies to the placement of fossil taxa. Here I present parsimony-based phylogenetic analyses of extant and fossil platyrrhines based on an anatomical dataset of 399 dental characters and osteological features of the cranium and postcranium. I sample 16 extant taxa (one from each platyrrhine genus) and 20 extinct taxa of platyrrhines. The tree structure is constrained with a "molecular scaffold" of extant species as implemented in maximum parsimony using PAUP with the molecular-based 'backbone' approach. The data set encompasses most of the known extinct species of platyrrhines, ranging in age from latest Oligocene (∼26 Ma) to the Recent. The tree is rooted with extant catarrhines, and Late Eocene and Early Oligocene African anthropoids. Among the more interesting patterns to emerge are: (1) known early platyrrhines from the Late Oligocene through Early Miocene (26-16.5Ma) represent only stem platyrrhine taxa; (2) representatives of the three living platyrrhine families first occur between 15.7 Ma and 13.5 Ma; and (3) recently extinct primates from the Greater Antilles (Cuba, Jamaica, Hispaniola) are sister to the clade of extant platyrrhines and may have diverged in the Early Miocene. It is probable that the crown platyrrhine clade did not originate before about 20-24 Ma, a conclusion consistent with the phylogenetic analysis of fossil taxa presented here and with recent molecular clock estimates. The following biogeographic scenario is consistent with the phylogenetic findings and climatic and geologic evidence: Tropical South America has been a center for platyrrhine diversification since platyrrhines arrived on the continent in the middle Cenozoic. Platyrrhines dispersed from tropical South America to Patagonia at ∼25-24 Ma via a "Paraná Portal" through eastern South America across a retreating Paranense Sea. Phylogenetic bracketing suggests Antillean primates arrived via a sweepstakes route or island chain from northern South America in the Early Miocene, not via a proposed land bridge or island chain (GAARlandia) in the Early Oligocene (∼34 Ma). Patagonian and Antillean platyrrhines went extinct without leaving living descendants, the former at the end of the Early Miocene and the latter within the past six thousand years. Molecular evidence suggests crown platyrrhines arrived in Central America by crossing an intermittent connection through the Isthmus of Panama at or after 3.5Ma. Any more ancient Central American primates, should they be discovered, are unlikely to have given rise to the extant Central American taxa in situ.