68 research outputs found

    Optimality conditions in terms of Bouligand generalized differentials for a nonsmooth semilinear elliptic optimal control problem with distributed and boundary control pointwise constraints

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    We prove a novel optimality condition in terms of Bouligand generalized differentials for a local minimizer of optimal control problems governed by a nonsmooth semilinear elliptic partial differential equation with both distributed and boundary unilateral pointwise control constraints, in which the nonlinear coefficient in the state equation is not differentiable at one point. Therefore, the Bouligand subdifferential of this nonsmooth coefficient in every point consists of one or two elements that will be used to construct the two associated Bouligand generalized derivatives of the control-to-state operator in any admissible control. We also establish the optimality conditions in the form of multiplier existence. There, in addition to the existence of the adjoint state and of the nonnegative multipliers associated with the pointwise constraints as usual, other nonnegative multipliers exist and correspond to the nondifferentiability of the control-to-state mapping. The latter type of optimality conditions shall be applied to the optimal control problems without distributed and boundary pointwise constraints to derive the so-called \emph{strong} stationarity conditions, where the sign of the associated adjoint state does not vary on the level set of the corresponding optimal state at the value of nondifferentiability.Comment: 33 page

    Monte Carlo Simulation of Correction Factors for Neutron Activation Foils

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    In the conventional neutron activation analysis, the elemental concentrations are normally determined from the comparison ratios between the measured specific activities of the sample and the standard reference material. An advantage in the comparison ratio method is that the systematic error due to neutron self-shielding and multi-scattering effects is canceled out, and the correction factors can be ignored but the preparation of reference standards to match the same conditions with those of various samples is the main difficulty. In the modern trend of neutron activation analysis, the K0-standardization method has been developed and applied in almost all the NAA laboratories. An important research work in the procedure under this method is the characteristic information regarding the neutron source, such as thermal and epithermal neutron fluxes, and epithermal spectrum shape-factor. These neutron spectrum parameters are experimentally determined by using the activation foils, in which the corrections for all neutron effects cause systematic errors should be taken into account. Using the MCNP5 code, a well-known Monte Carlo simulation program, the results of correction factors of thermal, epithermal and resonance neutron self-shielding factors for Au, Co, Mn, W activation foils are presented in this chapter

    The need for values education programs for both pre-service teachers and in-service teachers in Vietnam

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    This paper investigates the perceptions of pre-service teachers and in-service teachers regarding the concept of 'values education' and the preparation of values education in professional programs in Vietnam. Furthermore, the pedagogical strategies employed by teachers in addressing values education situations in their classrooms are explored. A qualitative research design was employed, involving interviews with forty-three pre-service teachers from a university. Additionally, eighteen teachers from two different high schools were interviewed, and their teaching sessions, along with school assemblies, were observed. The findings reveal that values education is primarily understood as the instruction of living skills and moral education. There is a lack of conceptualization and knowledge regarding values education among the participants. Both pre-service teachers and in-service teachers did not receive formal values education programs during their university education, and the support provided by schools in this regard was limited. Teachers tended to integrate values education into subjects randomly and subjectively, without employing advanced strategies. Inconsistencies in implementation and challenges associated with teaching values were observed. Highlighting an urgent necessity, this article emphasizes the imperative need for values education programs tailored for both pre-service and in-service teachers in Vietnam. It underscores the significance of adequately equipping teachers to effectively address values education in their classroom

    A Method to Construct an Extension of Fuzzy Information Granularity Based on Fuzzy Distance

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    In fuzzy granular computing, a fuzzy granular structure is the collection of fuzzy information granules and fuzzy information granularity is used to measure the granulation degree of a fuzzy granular structure. In general, the fuzzy information granularity characterizes discernibility ability among fuzzy information granules in a fuzzy granular structure. In recent years, researchers have proposed some concepts of fuzzy information granularity based on partial order relations. However, the existing forms of fuzzy information granularity have some limitations when evaluating the fineness/coarseness between two fuzzy granular structures. In this paper, we propose an extension of fuzzy information granularity based on a fuzzy distance measure. We prove theoretically and experimentally that the proposed fuzzy information granularity is the best one to distinguish fuzzy granular structures. ACM Computing Classification System (1998): I.5.2, I.2.6

    Factors affecting learner’s satisfaction towards online learning during COVID-19 pandemic: A case study of Vietnam

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    Online learning is being considered a new model of knowledge exchange in modern education. In parallel with the incredible impacts of the global pandemic, this is considered an opportunity to promote the development of online learning globally. Therefore, this study proposed a research framework including four factors affecting learner satisfaction towards online learning during the COVID-19 pandemic at a university, which are system quality, service quality, transformational leadership, and self-efficacy. A questionnaire was conducted online to assess which 131 respondents were representative students from two large private universities in Da Nang: FPT University and Duy Tan University. The results from the regression analysis show that three factors have a positive impact on learner satisfaction during COVID-19. This study concludes that students at private universities in Da Nang prioritize system quality as the most significant factor in their satisfaction with the online learning system, followed by transformational leadership and the last one is self-efficacy. Therefore, it can be more strategic for private organizations, developers, software designers, or even transformation-trained trainers to be emphasized to build a system of processes for implementing online learning for students effectively

    Choosing the best machine tool in mechanical manufacturing

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    Machine tools are indispensable components and play an important role in mechanical manufacturing. The equipment of machine tools has a huge effect on the operational efficiency of businesses. Each machine tool type is described by many different criteria, such as cost, technological capabilities, accuracy, energy consumption, convenience in operation, safety for workers, working noise, etc. If the selection of machine is only based on one or several criteria, it will be really easy to make mistakes, which means it is not possible to choose the real best machine. A machine is considered to be the best only when it is chosen based on all of its criteria. This work is called multi-criteria decision-making (MCDM). In this study, the selection of machine tools has been done using two different multi-criteria decision-making methods, including the FUCA method (Faire Un Choix Adéquat) and the CURLI method (Collaborative Unbiased Rank List Intergration). These are two methods with very different characteristics. When using the FUCA method, it is necessary to normalize the data and determine the weights for the criteria. Meanwhile, if using the CURLI method, these two things are not necessary. The selection of these two distinct methods is intended to produce the most generalizable conclusions. Three types of machine tool, which are considered in this study, include grinding machine, drilling machine and milling machine. The number of grinders that were offered for selection was twelve, the number of drills that were surveyed in this study was thirteen, while nine were the number of milling machines that were given for selection. The objective of this study is to determine the best solution in each type of machine. The results of ranking the machines are very similar when using the two mentioned methods. Specially, in all the surveyed cases, the two methods FUCA and CURLI always find the same best alternative. Accordingly, it is possible to firmly come to a conclusion that the FUCA method and the CURLI method are equally effective in machine tool selection. In addition, this study has determined the best three machines corresponding to the three different machine type

    HEDGE ALGEBRAS, THE SEMANTICS OF VAGUE LINGUISTIC INFORMATION AND APPLICATION PROSPECTIVE

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    The report aims to show that hedge algebras model actually the proper qualitative semantics of words of linguistic variables based on the argument that the inherent qualitative semantics of words should be expressed through the order relationships, induced by the word semantics, between the words in their respective variable domains, as required by decision making of human daily lives. This makes the hedge algebra based approach to the word semantics quite different from the existing approaches and become the only approach that can immediately deal with the natural qualitative semantics of words. We explain clearly and systematically distinguished features and properties of this approach to show that these seem to make the approach to be sound and ensure its effectiveness in applications. This approach seems to be promising for development of hedge algebra-based method to solve problems in various application fields. For illustration, we will give a short overview of effective results some of the initial applications of hedge algebras in the fields of knowledge based systems and in fuzzy control

    Quality of Life and Suitability with Vietnamese Harmonious Face Index in Class III Malocclusion Patients

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    BACKGROUND: Maxillary Lefort I osteotomy, mandibular bilateral sagittal split ramus was frequently used in correcting skeletal class III malocclusion. There was a lack of research on class III malocclusion patients’ quality of life (QoL) after bimaxillary osteotomy. AIM: Class I Intermaxillary relationship was achieved, aesthetic was significantly improved. Significant improvement in Class III skeletal patients’ quality of life was acquired. The achievement of harmonious face would be beneficial to the facial aesthetics of patients, thus improving the quality of life. METHODS: Harmonious face index is an effective criterion in assessing the surgery’s outcome. In this study was conducted on 30 patients at Hanoi National Hospital of Odontostomatology, Viet Duc Hospital, and Hong Ngoc Hospital from April 2017 to April 2018, and it was a quasi-experimental study with self-comparison, 12 months follow up. RESULTS: Orthognathic surgery effectively corrected malocclusion crossbite, dental compensation, and helped to improve facial aesthetics. 100% of patients had the quality of life improved, good quality of life consisted of 86.7%. In comparison with a harmonious facial index of Kinh ethnic in Vietnam, 70% of patients achieved skeletal harmony, 63.3% of patients achieved dental harmony, 80% achieved soft tissue harmony. CONCLUSIONS: Vietnamese harmonious facial index should be used in planning and pre-surgical simulatio
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