• Nuclear Engineering and Technology
• /
• v.56 no.6
• /
• pp.2019-2028
• /
• 2024

Advanced nuclear reactors, especially the newly developed small and micro-reactors have complex neutron spectrum, which makes the deterministic reactor core calculations sensitive to the energy group structure of few-group cross-sections. To avoid significantly increasing the cost of energy discretization in the core calculation, two energy group structures with 31 groups and 33 groups were adopted for typical thermal and fast reactor cores, respectively. Then, an adaptive scheme of group division for reactor cores with a medium neutron spectrum was proposed. The works were based on the full spectrum nuclear reactor analysis code SARAX/TULIP. An equivalent one-dimensional model of the core was proposed to capture the key neutron spectrum features of the reactor core. Such features were used to adaptively determine a few-group structure for the following reactor core calculations. Then, the neutron spectrum in different zones with more details was calculated. With this spectrum, the cross-sections were condensed into the determined energy groups. Three tests based on different neutron spectrum were calculated to verify the schemes. The results show that using the adaptive energy group division scheme, the following core calculation can meet the accuracy requirement of different reactors with different neutron spectra.

• Journal of the Korean Institute of Navigation
• /
• v.23 no.1
• /
• pp.29-43
• /
• 1999

The production process of the compound-curved hull plates includes hull design, definition, fairing, modeling, lofting, cutting, and forming in sequence. Traditional fabrication methods and shop environment caused low level to productivity in medium and small sized shipyards. The most effective solution to solve those problems is to rationalize the layout of facilities. For the well-balanced development of domestic shipbuilding industry, it is urgently required to reduce the gap between modernized large sized shipyards and traditional small and medium sized shipyards in production technologies and efficiencies. For the efficient and accurate hull piece forming, all information from design to forming should be clarified and organized in a systematic manner. Thus, management of the information plays an important role in the computerized and automated of hull piece forming. The object of this paper is to survey the status of the field, to find out the feasibility and to introduce a draft of hull piece fabrication line for small and medium sized shipyards. The development of required system follows the object oriented technology to extend to simulation based system for carrying out physical product flow and facilities layout analysis. It is feasible to operate such a modernized facility for a group of small and medium shipyards who are unable to have each of their own facility because of its large amount of initial investment and insufficient work load.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.2
• /
• pp.301-308
• /
• 2020

This study focuses on determining the impacts of organizational culture on the accounting information system and the operational performance of small and medium-sized enterprises in Ho Chi Minh City. The paper is organized in five parts: introduction, literature review, research methodology, research results, and conclusion and policy implications. Based on the samples of 353 respondents working in small and mediumsized enterprises in Ho Chi Minh City, the research employs both qualitative and quantitative methods to find the answers for research questions. Group discussion, which yields final observed variables of the factors of organizational culture is used for qualitative method. Statistics, assessment of the reliability of Cronbach's Alpha scale, exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and structural equation modeling (SEM) are used for quantitative procedure. The results show that mission, involvement and inconsistency in organizational culture positively affect the accounting information system of small and medium-sized firms in Vietnam. In addition, mission, involvement, adaptability and consistency in organizational culture are found to have positive impacts on the firm operational performance. Another finding of the study is that the accounting information system has a positive effect on operational performance of small and medium-sized firms in Vietnam.

• KIEAE Journal
• /
• v.12 no.6
• /
• pp.3-10
• /
• 2012

Small park in the community is a public asset that is commonly used by the residents daily and performs an important role to activate the community. The purpose of this study is to draw a small park plan through community participation. In concrete, this study tries to find out the demand of the residents about their small park plan, observe the changes in their demand in the process of debate and analyze the effect of the residents' participation. Small group workshop method was adopted in the study and three groups were set up and surveys were made in two stages. Two dimensional pictogram cards and three dimensional digital park formation tools were used. The results of workshop study indicated as follows: Firstly, residents wanted to have community farming garden, green house and flower garden to grow plants, natural walls and safe resting facilities. Secondly, individual and diverse opinions presented at first could be converted to common opinions through mutual exchanges of opinions in the process of debates. Thirdly, digital park formation program functioned well as an effective visual tool to draw the attention and quick responses of the residents and to reach an agreement. It is expected that the results of this study show the effectiveness of residents' participation tools in the process of drawing agreements in the community society that requires the residents' demands and agreement and this study will be usefully utilized in planning community spaces with residents' participation hereafter.

• Education of Primary School Mathematics
• /
• v.15 no.2
• /
• pp.107-134
• /
• 2012

The purpose of this study is to investigate the effectiveness of two teaching methods of word problems, one based on mathematical modeling learning(ML) and the other on traditional learning(TL). Additionally, the influence of mathematical modeling learning in word problem solving behavior, application ability of real world experiences in word problem solving and the beliefs of word problem solving will be examined. The results of this study were as follows: First, as to word problem solving behavior, there was a significant difference between the two groups. This mean that the ML was effective for word problem solving behavior. Second, all of the students in the ML group and the TL group had a strong tendency to exclude real world knowledge and sense-making when solving word problems during the pre-test. but A significant difference appeared between the two groups during post-test. classroom culture improvement efforts. Third, mathematical modeling learning(ML) was effective for improvement of traditional beliefs about word problems. Fourth, mathematical modeling learning(ML) exerted more influence on mathematically strong and average students and a positive effect to mathematically weak students. High and average-level students tended to benefit from mathematical modeling learning(ML) more than their low-level peers. This difference was caused by less involvement from low-level students in group assignments and whole-class discussions. While using the mathematical modeling learning method, elementary students were able to build various models about problem situations, justify, and elaborate models by discussions and comparisons from each other. This proves that elementary students could participate in mathematical modeling activities via word problems, it results form the use of more authentic tasks, small group activities and whole-class discussions, exclusion of teacher's direct intervention, and classroom culture improvement efforts. The conclusions drawn from the results obtained in this study are as follows: First, mathematical modeling learning(ML) can become an effective method, guiding word problem solving behavior from the direct translation approach(DTA) based on numbers and key words without understanding about problem situations to the meaningful based approach(MBA) building rich models for problem situations. Second, mathematical modeling learning(ML) will contribute attitudes considering real world situations in solving word problems. Mathematical modeling activities for word problems can help elementary students to understand relations between word problems and the real world. It will be also help them to develop the ability to look at the real world mathematically. Third, mathematical modeling learning(ML) will contribute to the development of positive beliefs for mathematics and word problem solving. Word problem teaching focused on just mathematical operations can't develop proper beliefs for mathematics and word problem solving. Mathematical modeling learning(ML) for word problems provide elementary students the opportunity to understand the real world mathematically, and it increases students' modeling abilities. Futhermore, it is a very useful method of reforming the current problems of word problem teaching and learning. Therefore, word problems in school mathematics should be replaced by more authentic ones and modeling activities should be introduced early in elementary school eduction, which would help change the perceptions about word problem teaching.

• Geomechanics and Engineering
• /
• v.10 no.5
• /
• pp.577-598
• /
• 2016

This paper presents a numerical study of pile force distribution in a pile group foundation subjected to vertical load and large moment. The physical modeling of a pile foundation for a wind turbine is analyzed using 3D finite element software, PLAXIS 3D. The soil profile consists of several clay layers, which are modeled as Mohr-Coulomb material in an undrained condition. The piles in the pile group foundation are modeled as special elements called embedded pile elements. To model the problem of a pile group foundation, a small gap is created between the pile cap and underlying soil. The pile cap is modeled as a rigid plate element connected to each pile by a hinge. As a result, applied vertical load and large moment are transferred only to piles without any load sharing to underlying soil. Results of the study focus on pile load distribution for the square shape of a pile group foundation. Mathematical expression is proposed to describe pile force distribution for the cases of vertical load and large moment and purely vertical load.

• Journal of Distribution Science
• /
• v.14 no.6
• /
• pp.65-73
• /
• 2016

Purpose - Recently, the management conditions of small independent retailers are getting worse everyday as large-scale marts and franchised convenience stores are increasing. The objective of this research is to find out the antecedents and consequences of cooperation in voluntary chain in order to enhance small independent retailer's competitiveness. Voluntary chains, also called affiliation or symbol groups, or allied group represent a high market shared in some European countries like Italy, France, and Germany. Nevertheless, there are still limitations in this research from academic fields. Drawing from network theory, the author investigates the relationship between antecedent factors in voluntary chain cooperation, such as participation benefits, justice of compensation, and autonomy in voluntary chain, and relationship specific asset. The author also attempts to examine the relationship between the relationship specific asset and cooperation of voluntary chain member shop and cooperation and consequence factors of voluntary chain cooperation, such as efficiency, group cohesiveness, and long-term relationship. Research design, data, and methodology - The author presented conceptual framework integrating the major antecedents and consequences of voluntary chain cooperation. The data were collected from 174 independent small retailers who joined K-voluntary chain. K-voluntary chain consists of small independent retailers. In accordance with their status, each entrepreneur associated with the voluntary group can own one or more outlets and can be a part of the life and the decision-making process of the group. This participation is not based on company turnover or on the number of outlets, but based on a one member, one vote system. To verify the research model and test hypotheses, the author carefully investigated the reliability, content validity, convergent validity, and discriminant validity of the proposed model. The data were analyzed by using SPSS 18.0 and AMOS structural equation modeling program. Results - The results of this study are as follows. First, as antecedent variables, participation benefits and justice of compensation have positive effect on the relationship specific assets of voluntary chain members. Second, voluntary chain members' relationship specific asset also directly related to the level of its cooperation to chain headquarter. Third, cooperation of voluntary chain member shop facilitates efficiency, group cohesiveness, and long-term relationship. Unexpectedly, there are no effect autonomy in voluntary chain to relationship specific asset. Conclusions - This research shows several theoretical and practical implications to both marketing scholars and marketers. In terms of theoretical implications, this study applies to network theory and network theory variables to explain the antecedent and consequence factors of cooperation in voluntary chain. From the point of view from business management, most of all, this study shows the way how to reinforce competitiveness of voluntary chain. Specifically, it is necessary for voluntary chain headquarter to give higher level of participation benefit and justice of compensation to its members. Second, the results also indicate what the consequence factors of cooperation in voluntary chain. In other words, to increase the level of marketing efficiency, group cohesiveness, long-term orientation in retail voluntary chain, and chain headquarter need to facilitate participants' cooperation.

• Journal of The Korean Association For Science Education
• /
• v.32 no.5
• /
• pp.805-822
• /
• 2012

The purpose of this study was to explore the patterns of group model development about blood flow in the heart and reasoning process by small group interaction. The subjects were 14, 8th graders in a Science Gifted Center. The group discussion was made possible by using triggering questions that can be answered based on experiences of hands-on activities such as a siphon pump analogy model activity and a dissection of pigs' hearts. Despite participating in same activities, the groups showed different model development patterns: unchanged, persuasive, and elaborated. Due to the critical revising, the group's explanatory model was elaborated and developed in the added and elaborated pattern. As critical revising is a core element of the developing model, it is important to promote a group interaction so that students become critical and receptive. The pedagogical analogy model and conflict situation enabled students to present elaborated reasoning. The Inquiry activity with the pedagogical analogy model promote students' spontaneous reasoning in relation to direct experience. Therefore offering a pedagogical analogy model will help students evaluate, revise and develop their models of concerned phenomena in science classroom. Conflict situation by rebuttal enable students to justify more solid and elaborate a model close to the target model. Therefore, teachers need to facilitate a group atmosphere for spontaneous conflict situation.

• Nuclear Engineering and Technology
• /
• v.52 no.2
• /
• pp.287-295
• /
• 2020

Group method of data handling (GMDH) is considered one of the earliest deep learning methods. Deep learning gained additional interest in today's applications due to its capability to handle complex and high dimensional problems. In this study, multi-layer GMDH networks are used to perform uncertainty quantification (UQ) and sensitivity analysis (SA) of nuclear reactor simulations. GMDH is utilized as a surrogate/metamodel to replace high fidelity computer models with cheap-to-evaluate surrogate models, which facilitate UQ and SA tasks (e.g. variance decomposition, uncertainty propagation, etc.). GMDH performance is validated through two UQ applications in reactor simulations: (1) low dimensional input space (two-phase flow in a reactor channel), and (2) high dimensional space (8-group homogenized cross-sections). In both applications, GMDH networks show very good performance with small mean absolute and squared errors as well as high accuracy in capturing the target variance. GMDH is utilized afterward to perform UQ tasks such as variance decomposition through Sobol indices, and GMDH-based uncertainty propagation with large number of samples. GMDH performance is also compared to other surrogates including Gaussian processes and polynomial chaos expansions. The comparison shows that GMDH has competitive performance with the other methods for the low dimensional problem, and reliable performance for the high dimensional problem.

• Nuclear Engineering and Technology
• /
• v.37 no.6
• /
• pp.525-536
• /
• 2005

The interfacial area transport equation dynamically models the changes in interfacial structures along the flow field by mechanistically modeling the creation and destruction of dispersed phase. Hence, when employed in the numerical thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Accounting for the substantial differences in the transport mechanism for various sizes of bubbles, the transport equation is formulated for two characteristic groups of bubbles. The group 1 equation describes the transport of small-dispersed bubbles, whereas the group 2 equation describes the transport of large cap, slug or chum-turbulent bubbles. To evaluate the feasibility and reliability of interfacial area transport equation available at present, it is benchmarked by an extensive database established in various two-phase flow configurations spanning from bubbly to chum-turbulent flow regimes. The geometrical effect in interfacial area transport is examined by the data acquired in vertical fir-water two-phase flow through round pipes of various sizes and a confined flow duct, and by those acquired In vertical co-current downward air-water two-phase flow through round pipes of two different sizes.