• IE interfaces
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• v.20 no.2
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• pp.186-194
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• 2007

Recent deregulation of Korean electricity industry has made each power generation company pay more attention to maximizing its own profit instead of minimizing the overall system operation cost while guaranteeing system security. Electricity power generation problem is typically defined as the problem of determining both the on and off status and the power generation level of each generator under the given fuel constraints, which has been known as Profit-Based Unit Commitment (PBUC) problem. To solve the PBUC problem, the previous research mostly focused on devising Lagrangian Relaxation (LR) based heuristic algorithms due to the complexity of the problem and the nonlinearity of constraints and objectives. However, these heuristic approaches have been reported as less practical in real world applications since the computational run time is usually quite high and it may take a while to implement the devised heuristic algorithms as software applications. Especially when considering long-term planning problem which spans at least one year, the complexity becomes higher. Therefore, this paper proposes an explicit column generation algorithm using power generation patterns and the proposed algorithm is successfully applied to a Korean power generation company. The proposed scheme has a robust structure so that it is expected to extend general PBUC problems.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.5
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• pp.119-133
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• 2022

The purpose of this study is to examine how change recipients react to change (affective commitment to change) and how change leads to positive consequences (job satisfaction) in Revolution and Evolution, taking into account the change content (perceived change impact), change context (change climate), and change process (participation in the change process). The present study uses a deductive approach with an exploratory research design. Data was collected from 254 employees of the head offices of three major banks, who have gone through Revolution, and 354 employees of the head offices, three banks who have gone through Evolution in the last five years. The hypothesized model is tested and analyzed through structural equation modeling using SmartPLS. The findings revealed that, in the case of Revolution, the presence of the favorable context and process might revert the negative perception of the change and lead towards explicit positive reactions (affective commitment to change) and change consequences (job satisfaction). In the case of Evolution, the change can be more effectively implemented using favorable context and process by achieving explicit positive reactions (affective commitment to change) and change consequences (job satisfaction).

• Journal of Information Technology Services
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• v.22 no.1
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• pp.43-56
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• 2023

With the development of the e-commerce market, various types of products continue to be released. However, customers face an information overload problem in purchasing decision-making. Therefore, personalized recommendations have become an essential service in providing personalized products to customers. Recently, many studies on GCN-based recommender systems have been actively conducted. Such a methodology can address the limitation in disabling to effectively reflect the interaction between customer and product in the embedding process. However, previous studies mainly use implicit feedback data to conduct experiments. Although implicit feedback data improves the data scarcity problem, it cannot represent customers' preferences for specific products. Therefore, this study proposed a novel model combining explicit and implicit feedback to address such a limitation. This study treats the average ratings of customers and products as the features of customers and products and converts them into a high-dimensional feature vector. Then, this study combines ID embedding vectors and feature vectors in the embedding layer to learn the customer-product interaction effectively. To evaluate recommendation performance, this study used the MovieLens dataset to conduct various experiments. Experimental results showed the proposed model outperforms the state-of-the-art. Therefore, the proposed model in this study can provide an enhanced recommendation service for customers to address the information overload problem.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.23-26
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• 2023

본 논문에서는 서술형 수학 문제 풀이 모델의 숫자 대소관계 파악을 위한 명시적 자질추출방식 Explicit Feature Extraction(EFE) Reasoner 모델을 제안한다. 서술형 수학 문제는 자연현상이나 일상에서 벌어지는 사건을 수학적으로 기술한 문제이다. 서술형 수학 문제 풀이를 위해서는 인공지능 모델이 문장에 함축된 논리를 파악하여 수식 또는 답을 도출해야 한다. 때문에 서술형 수학 문제 데이터셋은 인공지능 모델의 언어 이해 및 추론 능력을 평가하는 지표로 활용되고 있다. 기존 연구에서는 문제를 이해할 때 숫자의 대소관계를 파악하지 않고 문제에 등장하는 변수의 논리적인 관계만을 사용하여 수식을 도출한다는 한계점이 존재했다. 본 논문에서는 자연어 이해계열 모델 중 SVAMP 데이터셋에서 가장 높은 성능을 내고 있는 Deductive-Reasoner 모델에 숫자의 대소관계를 파악할 수 있는 방법론인 EFE 를 적용했을 때 RoBERTa-base 에서 1.1%, RoBERTa-large 에서 2.8%의 성능 향상을 얻었다. 이 결과를 통해 자연어 이해 모델이 숫자의 대소관계를 이해하는 것이 정답률 향상에 기여할 수 있음을 확인한다.

• Journal of The Korean Association For Science Education
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• v.40 no.2
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• pp.127-140
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• 2020

This study investigated the influence of an explicit and reflective modeling instruction on the metamodeling knowledge of fourth-graders. Two fourth-grade classes in an elementary school in Seoul were selected and each class was assigned to an experimental group and a control group, respectively. The experimental group was engaged in explicit and reflective modeling instruction, whereas the control group was engaged in implicit modeling instruction. The two groups were surveyed before and after instruction on the basis of five metamodeling knowledge categories: definition, purpose, design/construction, changeability, and multiplicity. The experimental group showed positive changes in model's meaning, examples, purpose, changeability as well as multiplicity. In contrast, fewer students in the control group understood the meaning of the model and modeling. They also showed limited changes in their understandings with regards to the modeling instruction, and could not expand their understanding of the nature of model and modeling. The findings indicate that an explicit and reflective modeling instruction has positive influence on elementary students' metamodeling knowledge.

• Korean Journal of Cognitive Science
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• v.16 no.2
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• pp.141-154
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• 2005

The purpose of this study was to investigate the effects of implicit and explicit situation awareness instruction on decision making and event related brain potentials. Psychophysiological data obtained from 36 intermediated level tennis players whose National Tennis Rating Program(NTTP) belong 2 to 2.5 were compared. Participants were randomly assigned to one of three experimental groups: (1) implicit situation awareness, (2) explicit situation awareness, and (3) control group. A total of 90 clips were presented via a beam project screen, and participants pressed one of three jelly bean buttons to indicate the direction of ball hit. Dependent measures were the latencies and amplitudes of P300 on Pz, Cz, and Fz. The results of this study indicated that participants in the implicit situation awareness produced tenser P300, than participants in the explicit situation awareness group. The findings also indicated that single defense showed longer P300 latencies than single attack as well as double defense. The P300-amplitude of treatment groups were longer than control group. The Cz area showed shorer P300 latencies than Pz and Fz areas. In addition, single defense situation demonstrated longer P300 latencies than single attack and double defence situations. Based on this study, it is believed that implicit and explicit situation awareness instruction influence decision making in different ways.

• 한국노년학
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• v.37 no.2
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• pp.475-496
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• 2017

Increasing evidence shows that ageist attitudes towards older adults develop quite early in childhood in Western culture, yet, empirical research on this topic in Korea is lacking. It has been argued that as Korea has become more youth oriented, negative views of aging have emerged and Korean children are increasingly exposured to negative stereotypes of older adults. Nuclearization of family structure and consequent reduction of intergenerational interaction is considered to be another important factor. The purpose of this study is to find out whether Korean children have ageist attitudes. Acknowledging the possibility that children tend to report in socially appropriate ways to the explicit measures of ageism, we included implicit measures of ageism. Data was collected from 570 fourth to sixth grade elementary school children selected by quota sampling. The current study used Child-Age Implicit Association Test and two other explicit measurements. The original versions were modified to be culturally applicable to the Korean context. Results indicated that when measured explicitly, children do not report preferring younger person than older person. However when measured implicitly, it was found that children at this young age already reveal negative biases toward the elderly. Contrast to the fact that the level of explicit ageism is significantly different by demographic characteristics of children, no statistical difference in the level of implicit ageism is detected. Based on the results, implications are discussed.

• Korean Journal of Culture and Social Issue
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• v.26 no.3
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• pp.283-301
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• 2020

In Korean society, words related to misogyny are being created and spread out in the Internet communities and the Internet news posts comments. This study was conducted to investigate if exposure to misogynistic words affects misogynistic attitudes toward women. Study 1 examined the relationship between exposure of misogynistic words (the number of misogynistic words known and the level of Internet comments viewed) and explicit misogynistic attitudes. As a result, the greater the exposure of misogynistic words, the less explicit misogynistic attitudes were found among men. The result can be explained as a desensitization of stimuli caused by repetitive exposure to media. In Study 2, experiments were conducted to manipulate the exposure of misogynistic words and to identify the relationship between implicit misogynistic attitudes through implicit association tests. Results of analysis show that implicit misogyny attitude is stronger as male participants are exposed to misogynistic words. The finding of this study suggests that explicit and implicit attitudes toward misogyny can diverge. It also implies that the exposure to misogynistic words can affect men's and women's attitudes in a different manner.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.9-16
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• 2024

Using the proper orthogonal decomposition (POD) based intrusive reduced order model (ROM), the total degrees of freedom of the structural system can be significantly reduced and the critical time step satisfying the conditional stability increases in the explicit time integrations. In this study, therefore, the changes in the critical time step in the explicit time integrations are investigated using both the POD-ROM and Voronoi-cell lattice model (VCLM). The snapshot matrix is composed of the data from the structural response under the arbitrary dynamic loads such as seismic excitation, from which the POD-ROM is constructed and the predictive capability is validated. The simulated results show that the significant reduction in the computational time can be achieved using the POD-ROM with sufficiently ensuring the numerical accuracy in the seismic analyses. In addition, the validations show that the POD based intrusive ROM is compatible with the Voronoi-cell lattice based explicit dynamic analyses. In the future study, the research results will be utilized as an elemental technology for the developments of the real-time predictive models or monitoring system involving the high-fidelity simulations of structural dynamics.

• Proceedings of the Korea Water Resources Association Conference
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• 1992.07a
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• pp.419-427
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• 1992