883 resultados para Tags set expansion
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The paper presents an extended genetic algorithm for solving the optimal transmission network expansion planning problem. Two main improvements have been introduced in the genetic algorithm: (a) initial population obtained by conventional optimisation based methods; (b) mutation approach inspired in the simulated annealing technique, the proposed method is general in the sense that it does not assume any particular property of the problem being solved, such as linearity or convexity. Excellent performance is reported in the test results section of the paper for a difficult large-scale real-life problem: a substantial reduction in investment costs has been obtained with regard to previous solutions obtained via conventional optimisation methods and simulated annealing algorithms; statistical comparison procedures have been employed in benchmarking different versions of the genetic algorithm and simulated annealing methods.
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A combinatorial mathematical model in tandem with a metaheuristic technique for solving transmission network expansion planning (TNEP) using an AC model associated with reactive power planning (RPP) is presented in this paper. AC-TNEP is handled through a prior DC model while additional lines as well as VAr-plants are used as reinforcements to cope with real network requirements. The solution of the reinforcement stage can be obtained by assuming all reactive demands are supplied locally to achieve a solution for AC-TNEP and by neglecting the local reactive sources, a reactive power planning (RPP) will be managed to find the minimum required reactive power sources. Binary GA as well as a real genetic algorithm (RCA) are employed as metaheuristic optimization techniques for solving this combinatorial TNEP as well as the RPP problem. High quality results related with lower investment costs through case studies on test systems show the usefulness of the proposal when working directly with the AC model in transmission network expansion planning, instead of relaxed models. (C) 2010 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We present a bilevel model for transmission expansion planning within a market environment, where producers and consumers trade freely electric energy through a pool. The target of the transmission planner, modeled through the upper-level problem, is to minimize network investment cost while facilitating energy trading. This upper-level problem is constrained by a collection of lower-level market clearing problems representing pool trading, and whose individual objective functions correspond to social welfare. Using the duality theory the proposed bilevel model is recast as a mixed-integer linear programming problem, which is solvable using branch-and-cut solvers. Detailed results from an illustrative example and a case study are presented and discussed. Finally, some relevant conclusions are drawn.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The taxonomy of the N(2)-fixing bacteria belonging to the genus Bradyrhizobium is still poorly refined, mainly due to conflicting results obtained by the analysis of the phenotypic and genotypic properties. This paper presents an application of a method aiming at the identification of possible new clusters within a Brazilian collection of 119 Bradryrhizobium strains showing phenotypic characteristics of B. japonicum and B. elkanii. The stability was studied as a function of the number of restriction enzymes used in the RFLP-PCR analysis of three ribosomal regions with three restriction enzymes per region. The method proposed here uses Clustering algorithms with distances calculated by average-linkage clustering. Introducing perturbations using sub-sampling techniques makes the stability analysis. The method showed efficacy in the grouping of the species B. japonicum and B. elkanii. Furthermore, two new clusters were clearly defined, indicating possible new species, and sub-clusters within each detected cluster. (C) 2008 Elsevier B.V. All rights reserved.
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The purpose of this study was to evaluate the setting time and the thermal expansion coefficient of 2 endodontic cements, MTA-Angelus and a novel cement called CER. The setting time was determined in accordance to ANSI/ADA specifications no. 57. Three samples of 10 mm diameter and 2 mm thickness were prepared for each cement. The thermal expansion measurements were performed by strain gauge technique. Four samples of each cement were prepared using silicone rings of 5 mm diameter and 2 mm thickness. The data were analyzed statistically using the Student t test. The setting time obtained for the MTA-Angelus and CER cements was 15 (SD 1) min and 7 (SD 1) min, respectively. The linear coefficient of thermal expansion was 8.86 (SD 0.28) mu strain/degrees C for MTA-Angelus and 11.76 (SD 1.20) mu strain/degrees C for CER. The statistical analysis showed significant difference (P < .05) in the setting time and linear coefficient of thermal expansion between the 2 cements. The CER cement has a coefficient of expansion similar to dentin, which could contribute to a decrease of microleakage degree.
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This study aimed to analyze the work of social workers at the Hospital Universitário Onofre Lopes (HUOL), with the analytical approach the contracting process with the HUOL with the National Health System (SUS), which is set from 2004. Thus, this study sought in times of state reform, restructuring and tension between enlargement / reduction of social and labor rights, understanding the limits and possibilities of social work in HUOL, analyzing how these determinations bounce in the practice of social workers included in the collective process of health work. From a theoretical and methodological historical and dialectical materialism, we conducted literature search, in which developed book report and readings of texts, articles, books that focus on the central categories of the study, namely: Work, Social Work, Health, Health Reform , Project ethical and professional politician. Operationalized also a documentary research, on the Brazilian Public Health Policy, (SUS) and of the Education, as well as research field in which we conducted interviews with 11 social workers, employees packed the HUOL. We conclude that social workers did not participate in the discussion process of contracting the HUOL with the Municipal Health Secretariat of Natal, RN, manager of health and full resetting of user access, via reference setting - counter-referral services provided by the hospital brought the main demands on Social Work guidance regarding the functionality of SUS, and the social intervention in the struggle to guarantee such access. However, the data show that the expansion of demands that require the intervention of the social worker at HUOL is not associated with quantitative growth of these professionals need. Such conditions inflect the possibilities of materialization of the professional ethical-political project, even though that these professionals worry and seek the intellectual improvement, quality of service and to guarantee the social rights of users in the professional practice everyday
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This paper is set in a scenario in which higher education institutions suffer from external pressure to increase efficiency. The legislation after the Law of Directives and Bases for Education (LDBE), from 1996, is characterized by the fragmentation in its implementation, raising a concern with flexibility and innovation in several normative devices as well as aspects that must be incorporated to its organizational structure. The policies examined in this thesis are: Distance Education (DE); Law of Innovation and the Program of Support to Restructuring and Expansion of Federal Universities (PSREFU). This thesis aims to observe to what extent the characteristics of innovation and flexibility, which mark the new post- LDBE educational legislation, influence the organizational redesign of the Federal University of Ceará (UFC). For being about implementation policies, using contingency approach in order to collect the internal dynamics permeating the redesign of higher education institutions, the thesis focuses on the impacts caused by flexibility and innovation. This is a qualitative research, with case study methods, archive research and semi-structured interviews with members of the university administration. The results don t allow us to confirm the adoption of a more flexible and innovative configuration in the university but it is possible to identify the presence of those elements in the implementation changes, characterizing the hybrid structure. The changes mainly expose the extension of the management of projects to the administrative and academic components related to the institution. In terms of projection, the study found changes in the elements which characterize the current setting and the tendency of the university for adopting a diverse organizational structure. However, if the decentralization of management persists, the academic units may adopt their own structural solutions, but with no evidence of changes in the professional organization in most units. In this perspective, this thesis states that there are difficulties when incorporating innovation and flexibility to their organizational structure, which lead to improvised solutions, superposing skills through the redundancy of structures created with the same purpose or copying exogenous solutions
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This research has as an empirical universe, the productive territory of red ware in the Seridó region of Rio Grande do Norte. In the last years this territory has gone through a process of appropriation that has been substantially changing the environmental and social dynamism of the place. However, the industry of red ware has been focusing in some areas, mainly, in the county of Parelhas and Carnaúba dos Dantas. From this point of view, the aim of this work consists in analyze the use of these areas by the red ware industry and the transformations occurred with the expansion of the number of industries and the productivity raise, that requires bigger amounts of earthenware and wood, resources that are low in referred territory. As the result of this process, the suitable alternative has been to acquire inputs in other Rio Grande do Norte counties, as well as in Paraíba counties. To reach the proposed objective, the methodology of this work was consisted of bibliographic and empirical research, regarding the occupation that this activity covers in the Seridó region. From the information obtained during the research, it can be stated that the inputs to the production execution in the red ware industry are acquired in the geographic nearby lands. The analysis of the stages of the production(acquisition of raw material, production and commercialization) showed that the activity acts in a continuous area, having as principal consumer market other northeastern states and the state of Pará. The present study revealed that the pottery activity is set as untenable, because of non-stopping use of the argil and wood, resources that are vanishing from the area, which consume causes a many problems such as deforestation and erosion. Besides, the sale of productive lands for the red ware industries makes harder its good use by the familiar agriculturists in the development of agriculture and cattle raising activity, which for many times is the main economic activity of the place. The precariousness reveals in the constant accidents at work, that most of them are neglected by the local authorities, without any penalty to the industries. Therefore, the industry of red ware in Seridó uses the territory as a resource, leaving its environmental problems that my compromise the quality of life of the actual and future generations
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Objective: The aim of the present study was to use facial analysis to determine the effects of rapid maxillary expansion (RME) on nasal morphology in children in the stages of primary and mixed dentition, with posterior cross-bite. Material and Methods: Facial photographs (front view and profile) of 60 patients in the pre-expansion period, immediate post-expansion period and one year following rapid maxillary expansion with a Haas appliance were evaluated on 2 occasions by 3 experienced orthodontists independently, with a 2-week interval between evaluations. The examiners were instructed to assess nasal morphology and had no knowledge regarding the content of the study. Intraexanniner and interexanniner agreement (assessed using the Kappa statistic) was acceptable. Results: From the analysis of the mode of the examiners' findings, no alterations in nasal morphology occurred regarding the following aspects: dorsunn of nose, alar base, nasal width of middle third and nasal base. Alterations were only detected in the nasolabial angle in 1.64% of the patients between the pre-expansion and immediate post-expansion photographs. In 4.92% of the patients between the immediate post-expansion period and 1 year following expansion; and in 6.56% of the patients between the pre-expansion period and one year following expansion. Conclusion: RME performed on children in stages of primary and mixed dentition did not have any impact on nasal morphology, as assessed using facial analysis.
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This study analyzed occlusal radiographs to compare the transverse changes produced in patients treated with rapid maxillary expansion using two types of appliances. The sample consisted of 31 children aged 7 to 10.6 years, of both genders, with posterior cross-bite. Fifteen children were treated with a tooth-borne expander and 16 were treated with a tooth-tissue-borne expander. Occlusal radiographs obtained at treatment onset and at the end of the retention period were digitized. The following variables were measured: intermolar distance (IMD), interapical distance (IApD), interbase distance (IBaD) and interarm distance (IArD). The results revealed increases in all measurements in both groups after rapid maxillary expansion. Comparison between groups revealed that the increases were greater in patients treated with the tooth-borne expander, except for the IArD measurement, which presented the same increase in both groups. Even though the IMD measurements differed between expanders, they were proportional to the activation of the appliances (IBaD). The increase in the IApD measurement was proportionally greater in the group treated with the tooth-borne expander (0.7:1.0) than in that treated with the tooth-tissue-borne expander (0.4:1.0). It was concluded that both appliances had similar effects, although the tooth-tissue-borne expander produced a lesser opening at the apical region of the incisors.
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Ingestion of a foreign object, including a dental object, can lead to a trip to the emergency room. This article describes the accidental swallowing of a key that was used to activate a rapid maxillary expander. An orthodontic patient swallowed the key while trying to activate the appliance at home. The object's trajectory was followed on radiographs until it was eliminated. Possible clinical complications, legal implications of this situation, and practices for prevention are described. (Am J Orthod Dentofacial Orthop 2011;140:266-8)