822 resultados para Worker heterogeneity


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We propose a taxonomy for heterogeneity and dynamics of swarms in PSO, which separates the consideration of homogeneity and heterogeneity from the presence of adaptive and non-adaptive dynamics, both at the particle and swarm level. It thus supports research into the separate and combined contributions of each of these characteristics. An analysis of the literature shows that most recent work has focussed on only parts of the taxonomy. Our results agree with prior work that both heterogeneity and dynamics are useful. However while heterogeneity does typically improve PSO, this is often dominated by the improvement due to dynamics. Adaptive strategies used to generate heterogeneity may end up sacrificing the dynamics which provide the greatest performance increase. We evaluate exemplar strategies for each area of the taxonomy and conclude with recommendations.

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Virus-specific CD8+ T cells are known to play an important role in the control of HIV infection. In this study we investigated whether there may be qualitative differences in the CD8+ T cell response in HIV-1- and HIV-2-infected individuals that contribute to the relatively efficient control of the latter infection. A molecular comparison of global TCR heterogeneity showed a more oligoclonal pattern of CD8 cells in HIV-1- than HIV-2-infected patients. This was reflected in restricted and conserved TCR usage by CD8+ T cells recognizing individual HLA-A2- and HLA-B57-restricted viral epitopes in HIV-1, with limited plasticity in their response to amino acid substitutions within these epitopes. The more diverse TCR usage observed for HIV-2-specific CD8 T cells was associated with an enhanced potential for CD8+ expansion and IFN- production on cross-recognition of variant epitopes. Our data suggest a mechanism that could account for any possible cross-protection that may be mediated by HIV-2-specific CD8+ T cells against HIV-1 infection. Furthermore, they have implications for HIV vaccine development, demonstrating an association between a polyclonal, virus-specific CD8+ T cell response and an enhanced capacity to tolerate substitutions within T cell epitopes.

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We study heterogeneity among nodes in self-organizing smart camera networks, which use strategies based on social and economic knowledge to target communication activity efficiently. We compare homogeneous configurations, when cameras use the same strategy, with heterogeneous configurations, when cameras use different strategies. Our first contribution is to establish that static heterogeneity leads to new outcomes that are more efficient than those possible with homogeneity. Next, two forms of dynamic heterogeneity are investigated: nonadaptive mixed strategies and adaptive strategies, which learn online. Our second contribution is to show that mixed strategies offer Pareto efficiency consistently comparable with the most efficient static heterogeneous configurations. Since the particular configuration required for high Pareto efficiency in a scenario will not be known in advance, our third contribution is to show how decentralized online learning can lead to more efficient outcomes than the homogeneous case. In some cases, outcomes from online learning were more efficient than all other evaluated configuration types. Our fourth contribution is to show that online learning typically leads to outcomes more evenly spread over the objective space. Our results provide insight into the relationship between static, dynamic, and adaptive heterogeneity, suggesting that all have a key role in achieving efficient self-organization.

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We identify two different forms of diversity present in engineered collective systems, namely heterogeneity (genotypic/phenotypic diversity) and dynamics (temporal diversity). Three qualitatively different case studies are analysed, and it is shown that both forms of diversity can be beneficial in very different problem and application domains. Behavioural diversity is shown to be motivated by input diversity and this observation is used to present recommendations for designers of collective systems.

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One of the main objectives in restructuring power industry is enhancing the efficiency of power facilities. However, power generation industry, which plays a key role in the power industry, has a noticeable share in emission amongst all other emission-generating sectors. In this study, we have developed some new Data Envelopment Analysis models to find efficient power plants based on less fuel consumption, combusting less polluting fuel types, and incorporating emission factors in order to measure the ecological efficiency trend. We then applied these models to measuring eco-efficiency during an eight-year period of power industry restructuring in Iran. Results reveal that there has been a significant improvement in eco-efficiency, cost efficiency and allocative efficiency of the power plants during the restructuring period. It is also shown that despite the hydro power plants look eco-efficient; the combined cycle ones have been more allocative efficient than the other power generation technologies used in Iran.

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With the growing environmental crisis affecting our globe, ideas to weigh economic or social progress by the ‘energy input’ necessary to achieve it are increasingly gaining acceptance. This question is intriguing and is being dealt with by a growing number of studies, focusing on the environmental price of human progress. Even more intriguing, however, is the question of which factors of social organization contribute to a responsible use of the resources of our planet to achieve a given social result (‘smart development’). In this essay, we present the first systematic study on how migration – or rather, more concretely, received worker remittances per GDP – helps the nations of our globe to enjoy social and economic progress at a relatively small environmental price. We look at the effects of migration on the balance sheets of societal accounting, based on the ‘ecological price’ of the combined performance of democracy, economic growth, gender equality, human development, research and development, and social cohesion. Feminism in power, economic freedom, population density, the UNDP education index as well as the receipt of worker remittances all significantly contribute towards a ‘smart overall development’, while high military expenditures and a high world economic openness are a bottleneck for ‘smart overall development’.

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A cikkben paneladatok segítségével a magyar gabonatermesztő üzemek 2001 és 2009 közötti technikai hatékonyságát vizsgáljuk. A technikai hatékonyság szintjének becslésére egy hagyományos sztochasztikus határok modell (SFA) mellett a látens csoportok modelljét (LCM) használjuk, amely figyelembe veszi a technológiai különbségeket is. Eredményeink arra utalnak, hogy a technológiai heterogenitás fontos lehet egy olyan ágazatban is, mint a szántóföldi növénytermesztés, ahol viszonylag homogén technológiát alkalmaznak. A hagyományos, azonos technológiát feltételező és a látens osztályok modelljeinek összehasonlítása azt mutatja, hogy a gabonatermesztő üzemek technikai hatékonyságát a hagyományos modellek alábecsülhetik. _____ The article sets out to analyse the technical efficiency of Hungarian crop farms between 2001 and 2009, using panel data and employing both standard stochastic frontier analysis and the latent class model (LCM) to estimate technical efficiency. The findings suggest that technological heterogeneity plays an important role in the crop sector, though it is traditionally assumed to employ homogenous technology. A comparison of standard SFA models that assumes the technology is common to all farms and LCM estimates highlights the way the efficiency of crop farms can be underestimated using traditional SFA models.

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Given the seriousness of substance abuse as a child welfare problem, the purpose of this study was to examine the relative effectiveness of an inservice training curriculum for child welfare workers. The training was designed to improve worker knowledge and attitudes in working with substance abusing families. Seventy (70) child welfare workers from public and private agencies in two south Florida counties participated in a pretest/posttest control group design that also trained and retested the control group. The literature review supports that the general preparedness of child welfare workers for the issues presented by substance abusing families is in question. Confounding this problem is a lack of understanding of substance abuse dynamics, worker biases, and predispositions. The two research hypotheses focused on whether inservice training could increase worker knowledge and improve worker attitudes in working with this population. Training delivery was in the form of a five-day inservice focusing on an array of substance abuse knowledge and attitudinal topics. Separate knowledge and attitude instruments were developed for the research and were administered, before and after training, to a purposive sample of participants that were randomly assigned to the experimental and control groups. The data analysis supported the research hypotheses but raised a question. Specifically, the experimental group demonstrated significant improvement in posttest scores on both instruments after receiving the training; whereas the control group, with training withheld, also demonstrated a significant improvement at posttest, but only on the knowledge instrument. Although the question was unanswered, when examined at a more critical significance level, only the experimental group remained significant. The hypotheses were reconfirmed when, after training and retesting, the control group also displayed significant improvement on both instruments. The findings support the conclusion that this substance abuse inservice was effective in improving worker knowledge and attitudes regarding working with substance abusing families. As an implication for social work practice, it suggests that similar inservice training can be a viable training resource when formal substance abuse training is unavailable. Additional research is suggested regarding to what degree increased substance abuse knowledge and improved worker attitudes correlate with improved practice.

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This thesis would not have been possible without the aid of my family, friends, laboratory members, and professors. First and foremost, I would like to thank Dr. Kalai Mathee for allowing me to enter her lab in August 2007 and enabling to embark on this journey. This experience has transformed me into more mature scientist, teaching me how to ask the right questions and the process needed to solve them. I would also like to acknowledge Dr. Lisa Schneper. She has helped me throughout the whole process, by graciously giving me input at every step of the way. I would like to express gratitude to Dr. Jennifer Richards for all her input in writing the thesis. She has been a great teacher and being in her class has been a pleasure. Moreover, I would like to thank all the committee members for their constructive criticism throughout the process. When I entered the lab in August, there was one person who literally was by my side, Melissa Doud. Without your input and guidance I would not have even been able to do these experiments. I would also like to thank you and Dr. Light for allowing me to meet some cystic fibrosis patients. It has allowed me to put a face on the disease, and help the patients' fight. For a period before I had entered the lab, Ms. Doud had an apprentice, who started the fungal aspect of the project, Caroline Veronese. Her initial work has enabled me to prefect the protocols and complete the ITS 1 region.One very unique aspect about Dr. Mathee's lab is the camaraderie. I would like to thank all the lab members for the good times in and out of the lab. These individuals have been able to make smile and laugh in parties and lab meetings. I would like to individually thank Balachandar Dananjeyan, Deepak Balasubramanian, and V arinderpal Singh Pannu for all the PCR help and Natalie Maricic for the laughs and being a great classmate. Last, but not least, I would like to acknowledge my family and friends for their support and keeping me sane: Cecilia, my mother, Mohammad, my father, Amir, my older brother, Billal, my younger brother, Ouday Akkari and Stephanie De Bedout, my best friends.

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The management of residential landscapes occurs within a complex socio-ecological system linking household decision-making with ecological properties, multi-scalar human drivers, and the legacy effects of past management. Conventional wisdom suggests that resource-intensive turf grass yards are the most common landscaping outcome, resulting in a presumed homogeneous set of residential landscaping practices throughout North America. We examine this homogenization thesis through an interview-based, cross-site study of residential landscape management in Boston, Phoenix, and Miami. Counter to the homogeneity thesis, we find that yard management practices often exhibit heterogeneity, for example, in groundcover choice or use of chemical inputs. The degree of heterogeneity in management practices varies according to the scale of analysis, and is the outcome of a range of constraints and opportunities to which households respond differently depending on their existing yard and landscaping preferences. This study highlights the importance of multi-scalar and cross-site analyses of decision-making in socio-ecological systems, and presents opportunities for longitudinal and cross-site research to examine the extent to which homogeneity is actually present in the management of residential landscapes over time and in diverse places.

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This article presents the findings of a central Florida study of lodging and restaurant managers as well as entry-level workers who were graduates of hospitality management programs. It provides a theoretical construct as a basis of the methodology employed. The article then reports the findings of perceptions of desired knowledge, skills and abilities, and attitudes associated with entry-level employees. It further compares desired levels of preparation for entry-level positions in the industry as reported by respondents of both groups. Finally, the authors present conclusions and implications for central Florida practitioners and educators.

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While there has been frequent research into the area of older workers in other industries, the food service field has not been examined in detail. The author explores the potential role of older workers in food services and offers suggestions toward formulating policy for such individuals.

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Peer reviewed

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.