977 resultados para Search problems


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Efforts presented by the scientific community in recent years towards the development of numerous green chemical processes and wastewater treatment technologies are presented and discussed. In the light of these approaches, environmentally friendly technologies, as well as the key role played by the well-known advanced oxidation processes, are discussed, giving special attention to the ones comprising ozone applications. Fundamentals and applied aspects dealing with ozone technology and its application are also presented.

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Actualmente, las necesidades de mejora en gestión de stocks y la mayor disponibilidad de sistemas automáticos, están haciendo que muchas empresas inviertan en técnicas modernas para almacenamiento y manipulación de productos. Esta inquietud también ha llegado a las farmacias, que de forma lenta pero firme se van apuntando a su robotización. Uno de los principales problemas a los que se enfrentan las farmacias es la pérdida de tiempo en la gestión y búsqueda de medicamentos, provocando situaciones negativas como las esperas, la falta de tiempo para una atención más personalizada y como consecuencia, la pérdida de clientes. Este inconveniente y la necesidad de mejora en la gestión de los stocks han hecho que aparezcan los Sistemas de dispensación automática de productos farmacéuticos. El dispensador automático facilita el trabajo del farmacéutico al automatizar la búsqueda de la medicina requerida, aumentando la dedicación al cliente y reduciendo los tiempos no productivos y las colas. El presente estudio desarrolla un sistema de dispensación automático de fármacos aplicado a farmacias con una rotación de medicamentos media/ baja, valorando tanto su viabilidad técnica como económica. El almacén propuesto es de tipo caótico con sistema de carga, almacenamiento y descarga completamente automáticos. La mayoría de diseños y conceptos expuestos en este trabajo son de desarrollo propio del autor con el único objetivo de la búsqueda de nuevas soluciones para conseguir un sistema de almacenamiento efectivo y de máximo rendimiento.

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Metaheuristic methods have become increasingly popular approaches in solving global optimization problems. From a practical viewpoint, it is often desirable to perform multimodal optimization which, enables the search of more than one optimal solution to the task at hand. Population-based metaheuristic methods offer a natural basis for multimodal optimization. The topic has received increasing interest especially in the evolutionary computation community. Several niching approaches have been suggested to allow multimodal optimization using evolutionary algorithms. Most global optimization approaches, including metaheuristics, contain global and local search phases. The requirement to locate several optima sets additional requirements for the design of algorithms to be effective in both respects in the context of multimodal optimization. In this thesis, several different multimodal optimization algorithms are studied in regard to how their implementation in the global and local search phases affect their performance in different problems. The study concentrates especially on variations of the Differential Evolution algorithm and their capabilities in multimodal optimization. To separate the global and local search search phases, three multimodal optimization algorithms are proposed, two of which hybridize the Differential Evolution with a local search method. As the theoretical background behind the operation of metaheuristics is not generally thoroughly understood, the research relies heavily on experimental studies in finding out the properties of different approaches. To achieve reliable experimental information, the experimental environment must be carefully chosen to contain appropriate and adequately varying problems. The available selection of multimodal test problems is, however, rather limited, and no general framework exists. As a part of this thesis, such a framework for generating tunable test functions for evaluating different methods of multimodal optimization experimentally is provided and used for testing the algorithms. The results demonstrate that an efficient local phase is essential for creating efficient multimodal optimization algorithms. Adding a suitable global phase has the potential to boost the performance significantly, but the weak local phase may invalidate the advantages gained from the global phase.

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Ethical problems occurring during the practical training period of Finnish nursing students The present study focused on nursing students adopting the professional code of conduct during their supervised practical training. The study was carried out in two phases. During the first phase, the objective was to survey ethical problems occurring in practical training as well as how these problems are detected and resolved by nursing students and their supervisors at different stages of their studies. In the second phase, the capability of the nursing students about to graduate to detect and resolve ethical problems was described and analyzed. The students’ capacity for self-instruction, independent search for information as well as factors related to teaching of ethics were determined within this phase. Further, an extensive literature review was carried out to complement the study. Thus, the main objective of the thesis was to make suggestions for the development of the teaching of ethics and supervision in nursing studies and in practice. In the first part of the empirical phase (2002–2005), the views of the nursing students (n =18) were clarified with themed open essay questions. Furthermore, the views of the supervising nurses (n = 115) were established by utilizing a series of themed questions and group interviews. During the second phase (2006–2007), the data for the analyses were collected from nursing students in their graduating stage (n = 319) by a national Internet-based questionnaire. The results of the first phase were examined with contentanalysis and those of the second phase both statistically and by using content analysis. Ethical problems occurring during supervised practical training were typically connected to a patient or a client, a member of the nursing staff or to a student, while solutions were connected to preparation and the action to solve the problem in question. Ethical dilemmas were classified as legal, ethical comportment and uncertainty problems as well as personal and institutional ones. The solutions for these problems were further grouped as based on facts, instructor/staff/member/specialist or patient/client/relative. The results showed that although the nursing students about to graduate had detected many ethical problems both independently as well as together with the nursing staff during every practical training period, they were able to resolve only few of them. Ethical problems were most frequently encountered during training in psychiatric nursing. On the grounds of their own impressions, the nursing students stated that their ability to detect and solve ethical problems improved during their training period. The primary factors related to this enhancement of their skills were teaching and the students’ readiness for selfinstruction. Gender, orientation of the studies and age were observed to be the most important among the underlying factors influencing the capability to detect and solve ethical problems as well as to engage in self-instruction. Based on the results obtained, suggestions for development as well as topics for further studies are presented through teaching of professional ethics and supervision during practical training.

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The results obtained in several yield tests, at an international level (mainly the famous PISA 2003 report, by the OCDE), have raised a multiplicity of performances in order to improve the students' yield regarding problem solving. In this article we set a clear guideline on how problems should be used in Mathematics lessons, not for obtaining better scores in the yield tests but for improving the development of Mathematical thinking in students. From this perspective, the author analyses, through eight reflections, how the concept of problem, transmitted both in the school and from society, influences the students

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Coal, natural gas and petroleum-based liquid fuels are still the most widely used energy sources in modern society. The current scenario contrasts with the foreseen shortage of petroleum that was spread out in the beginning of the XXI century, when the concept of "energy security" emerged as an urgent agenda to ensure a good balance between energy supply and demand. Much beyond protecting refineries and oil ducts from terrorist attacks, these issues soon developed to a portfolio of measures related to process sustainability, involving at least three fundamental dimensions: (a) the need for technological breakthroughs to improve energy production worldwide; (b) the improvement of energy efficiency in all sectors of modern society; and (c) the increase of the social perception that education is a key-word towards a better use of our energy resources. Together with these technological, economic or social issues, "energy security" is also strongly influenced by environmental issues involving greenhouse gas emissions, loss of biodiversity in environmentally sensitive areas, pollution and poor solid waste management. For these and other reasons, the implementation of more sustainable practices in our currently available industrial facilities and the search for alternative energy sources that could partly replace the fossil fuels became a major priority throughout the world. Regarding fossil fuels, the main technological bottlenecks are related to the exploitation of less accessible petroleum resources such as those in the pre-salt layer, ranging from the proper characterization of these deep-water oil reservoirs, the development of lighter and more efficient equipment for both exploration and exploitation, the optimization of the drilling techniques, the achievement of further improvements in production yields and the establishment of specialized training programs for the technical staff. The production of natural gas from shale is also emerging in several countries but its production in large scale has several problems ranging from the unavoidable environmental impact of shale mining as well as to the bad consequences of its large scale exploitation in the past. The large scale use of coal has similar environmental problems, which are aggravated by difficulties in its proper characterization. Also, the mitigation of harmful gases and particulate matter that are released as a result of combustion is still depending on the development of new gas cleaning technologies including more efficient catalysts to improve its emission profile. On the other hand, biofuels are still struggling to fulfill their role in reducing our high dependence on fossil fuels. Fatty acid alkyl esters (biodiesel) from vegetable oils and ethanol from cane sucrose and corn starch are mature technologies whose market share is partially limited by the availability of their raw materials. For this reason, there has been a great effort to develop "second-generation" technologies to produce methanol, ethanol, butanol, biodiesel, biogas (methane), bio-oils, syngas and synthetic fuels from lower grade renewable feedstocks such as lignocellulosic materials whose consumption would not interfere with the rather sensitive issues of food security. Advanced fermentation processes are envisaged as "third generation" technologies and these are primarily linked to the use of algae feedstocks as well as other organisms that could produce biofuels or simply provide microbial biomass for the processes listed above. Due to the complexity and cost of their production chain, "third generation" technologies usually aim at high value added biofuels such as biojet fuel, biohydrogen and hydrocarbons with a fuel performance similar to diesel or gasoline, situations in which the use of genetically modified organisms is usually required. In general, the main challenges in this field could be summarized as follows: (a) the need for prospecting alternative sources of biomass that are not linked to the food chain; (b) the intensive use of green chemistry principles in our current industrial activities; (c) the development of mature technologies for the production of second and third generation biofuels; (d) the development of safe bioprocesses that are based on environmentally benign microorganisms; (e) the scale-up of potential technologies to a suitable demonstration scale; and (f) the full understanding of the technological and environmental implications of the food vs. fuel debate. On the basis of these, the main objective of this article is to stimulate the discussion and help the decision making regarding "energy security" issues and their challenges for modern society, in such a way to encourage the participation of the Brazilian Chemistry community in the design of a road map for a safer, sustainable and prosper future for our nation.

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The aim of this study is to investigate the consumer search behavior in high involvement purchases. The results of this research provide the descriptive analysis of the information search phase which is a part of the decision-making process. The study focuses on customer’s choice of the information sources, motivation behind it and different factors that influence the search behavior. Particular attention is paid to the purchase categorization and the differences in information search between products and services. The qualitative research method is chosen for this study. The data is gathered through ten theme interviews. Each participant of the interview describes his/her own search behavior in a product and a service case. The results indicate that consumer search behavior vary according to the purchase categorization, demographic, individual and situational factors. Moreover, the above-mentioned factors influence the purpose and position of the information search phase in a five-step decision making model.

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The present text proposes a discussion on the concept of true friendship. The argument is grounded mostly on Aristotle's Nicomachean Ethics, Owen Flanagan's ethics as human ecology, and on contemporary authors' works about the Greek philosopher's concept of friendship. Given that human beings flourish through 1) exercising capacities, 2) being moral, and 3) having true friendships, difficulties to establish the level of trust required by true friendships turns the search itself (for them) morally valid.

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BACKGROUND: E-learning techniques are spreading at great speed in medicine, raising concerns about the impact of adopting them. Websites especially designed to host courses are becoming more common. There is a lack of evidence that these systems could enhance student knowledge acquisition. GOAL: To evaluate the impact of using dedicated-website tools over cognition of medical students exposed to a first-aid course. METHODS: Prospective study of 184 medical students exposed to a twenty-hour first-aid course. We generated a dedicated-website with several sections (lectures, additional reading material, video and multiple choice exercises). We constructed variables expressing the student's access to each section. The evaluation was composed of fifty multiple-choice tests, based on clinical problems. We used multiple linear regression to adjust for potential confounders. RESULTS: There was no association of website intensity of exposure and the outcome - beta-coeficient 0.27 (95%CI - 0.454 - 1.004). These findings were not altered after adjustment for potential confounders - 0.165 (95%CI -0.628 - 0.960). CONCLUSION: A dedicated website with passive and active capabilities for aiding in person learning had not shown association with a better outcome.