• Title/Summary/Keyword: Maximizing Total Regard

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A Study of Buffer Allocation in FMS based on Deadlock & Workload (FMS의 Deadlock과 Workload를 고려한 최적 버퍼 할당에 관한 연구)

  • 이정표;김경섭
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.10a
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    • pp.71-74
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    • 2000
  • Due to the complexity of parts flow and limited resources, FMS(Flexible Manufacturing System) develops blocking, starvation and deadlock problems, which reduce its performance. In order to minimize such problems buffers are imposed between workstations of the manufacturing lines. In this paper, we are concerned with finding the optimal buffer allocation with regard to maximizing system throughput in limited total buffer capacity situation of FMS. A grouping heuristic to solve the buffer allocation problem is proposed. Computer simulation using Arena will be experimented to show the validation of the proposed algotithm.

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A Study of Buffer Allocation in FMS based on Deadlock and Workload (Deadlock과 Workload에 따른 FMS의 버퍼 Capacity 결정에 관한 연구)

  • 김경섭;이정표
    • Journal of the Korea Society for Simulation
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    • v.9 no.2
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    • pp.63-73
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    • 2000
  • Due to the complexity of part flow and limited resources, FMS(Flexible Manufacturing System) develops blocking, starvation and deadlock problems, which reduce its performance. In order to minimize such problems buffers are imposed between workstations of the manufacturing lines. In this paper, we are concerned with finding the optimal buffer allocation with regard to maximizing system throughput in limited total buffer capacity situation of FMS. A dynamic programming algorithm to solve the buffer allocation problem is proposed. Computer simulation using Arena is experimented to show the validation of the proposed algorithm.

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Total Diet Study: For a Closer-to-real Estimate of Dietary Exposure to Chemical Substances

  • Kim, Cho-il;Lee, Jeeyeon;Kwon, Sungok;Yoon, Hae-Jung
    • Toxicological Research
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    • v.31 no.3
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    • pp.227-240
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    • 2015
  • Recent amendment on the Food Sanitation Act in Korea mandated the Minister of Food & Drug Safety to secure the scientific basis for management and reevaluation of standards and specifications of foods. Especially because the current food safety control is limited within the scope of 'Farm to Market' covering from production to retail in Korea, safety control at the plane of true 'Farm to Fork' scope is urgently needed and should include 'total diet' of population instead of individual food items. Therefore, 'Total Diet Study (TDS)' which provides 'closer-to-real' estimates of exposure to hazardous materials through analysis on table-ready (cooked) samples of foods would be the solution to more comprehensive food safety management, as suggested by World Health Organization and Food and Agriculture Organization of the United Nations. Although the protection of diets from hazards must be considered as one of the most essential public health functions of any country, we may need to revisit the value of foods which has been too much underrated by the meaningless amount of some hazardous materials in Korea. Considering the primary value of foods lies on sustaining life, growth, development, and health promotion of human being, food safety control should be handled not only by the presence or absence of hazardous materials but also by maximizing the value of foods via balancing with the preservation of beneficial components in foods embracing total diet. In this regard, this article aims to provide an overview on TDS by describing procedures involved except chemical analysis which is beyond our scope. Also, details on the ongoing TDS in Korea are provided as an example. Although TDS itself might not be of keen interest for most readers, it is the main user of the safety reference values resulted from toxicological research in the public health perspective.

IRIS Task Scheduling Algorithm Based on Task Selection Policies (태스크 선택정책에 기반을 둔 IRIS 태스크 스케줄링 알고리즘)

  • Shim, Jae-Hong;Choi, Kyung-Hee;Jung, Gi-Hyun
    • The KIPS Transactions:PartA
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    • v.10A no.3
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    • pp.181-188
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    • 2003
  • We propose a heuristic on-line scheduling algorithm for the IRIS (Increasing Reward with Increasing Service) tasks, which has low computation complexity and produces total reward approximated to that of previous on-line optimal algorithms. The previous on-line optimal algorithms for IRIS tasks perform scheduling on all tasks in a system to maximize total reward. Therefore, the complexities of these algorithms are too high to apply them to practical systems handling many tasks. The proposed algorithm doesn´t perform scheduling on all tasks in a system, but on (constant) W´s tasks selected by a predefined task selection policy. The proposed algorithm is based on task selection policies that define how to select tasks to be scheduled. We suggest two simple and intuitive selection policies and a generalized selection policy that integrates previous two selection policies. By narrowing down scheduling scope to only W´s selected tasks, the computation complexity of proposed algorithm can be reduced to O(Wn). However, simulation results for various cases show that it is closed to O(W) on the average.

The Effect on the Granodiorite Suspension Coated Indoor Finishing Materials for Reduction of TVOC Emissions (실내 마감재료의 TVOC 방출 저감을 위한 화강섬록암 현탁액 도포효과)

  • Lee, Jong-Gyu;Kim, Ji-Hyun;Lee, Jae-Yong;Lee, Soo-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.5
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    • pp.93-99
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    • 2008
  • The environment draws attention in the global community and a growing number of Koreans have interest in improving the quality of life, the importance of house environment has attracted the attention of the public. Against this backdrop, constructors have unveiled environmentally -friendly projects. However, they failed to establish people-oriented environment by being occupied with maximizing profitability through the improvement of brand image and caused sick house syndrome that has recently made controversy. In this regard, the study analyzed the mechanism of discharge of TVOC, one of the sick house syndrome-causing materials, that affects IAQ and its characteristics and examined the effect that granodiorite has on reduction of the discharge of TVOC in order to minimize damage. Experimental sample consisted of interior finishing materials frequently used in ceiling, wall and floor and adhesives used at a time of construction, and the TVOC of building materials was measured through the use of septum bottle unlike In the existing chamber method. Measures to counter the sick house syndrome were suggested by reducing the possible damage from the stage of selection of building material and by figuring out the effect that the granodiorite has on reduction of the discharge of TVOC.

Issues and Vision of Korea Maritime Police

  • Lee, Sangjib
    • Proceedings of KOSOMES biannual meeting
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    • 2000.05a
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    • pp.14-25
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    • 2000
  • Should the Korea Maritime Police Agency (KMPA) be a comprehensive, multi-functional organization for a unique on-scene service at sea, as in the case of the U.S. Coast Guard, or should it be simply a water police agency, confining its mission only to law enforcement? The argument about enlarging or limiting KMPA's function has been and will be repeated. In this paper, Lee Sangjib highlights the internal and external issues facing KMPA, stemming partly from deficiencies of its struggles for advancement of the organization and partly from shortcomings of political support for it. In this regard, he urges KMPA to practise a scientific management system for maximizing cost-effectiveness of its administrative resources and for maintaining its identity and characteristics as a lead maritime agency. In addition, he also suggests that KMPA adopt the Total Quality Management System for quality improvements in services and greater efficiency in its organization structure to meet the future competition in the changing political and legal environment. He further recommends the proactive, non-regulatory 'Prevention Through People' program, pioneered by the U.S. Coast Guard, as a way of changing KMPA's existing lopsidedly legalistic culture. He concludes by providing a 6-point vision statement for KMPA from the standpoint of favoring enlarging the function of KMPA.

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Effects of Education Service Quality on Relationship Management from the Service Distribution Perspective (교육서비스 품질이 관계관리에 미치는 영향: 서비스 유통 관점에서)

  • Cho, Hyun-Jin
    • Journal of Distribution Science
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    • v.13 no.3
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    • pp.41-49
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    • 2015
  • Purpose - Universities are placing a greater emphasis on relationship management as a source of competitive advantage due to increasingly competitive environments and social changes. The purpose of this study is to analyze the relationships among education service quality, relationship quality, and relationship performance from the perspective of service distribution. In other words, this study is focused on the role of education service quality with regard to relationship management. In this study, education service quality is divided into lecture, job assistance, student-faculty interaction, student-student interaction, facility welfare, and scholarship welfare quality components; relationship quality is composed of satisfaction and commitment; and relationship performance is divided into recommendation and defection intentions. Research design, data, and methodology - This study aims to identify how the various elements of education service quality affect satisfaction. Further, it aims to test the relationships among satisfaction, commitment, recommendation intentions, and defection intentions. Distribution and marketing students were randomly selected for the experiment. Out of the 380 administered questionnaires, a total of 361 respondents provided complete and usable data. The sample consisted of 232 males (64.3%) and 129 females (35.7%). The variables of the proposed model were measured through assessments that were measured on a 5-point Likert scale. Using Lisrel 8.7, a structural model was analyzed and the path coefficients were estimated. Results - The overall fit of the model was acceptable (χ2=1121.8 (df=603, P=0.00), GFI=0.967, NFI=0.974, CFI=0.981, RMR=0.021). The results generally supported the hypothesized relationships of the proposed model, except for Hypothesis 1. First, lecture, job assistance, student-faculty interaction, student-student interaction, and facility welfare quality were revealed to have positive effects on satisfaction. In particular, lecture and facility welfare quality had the strongest effects on satisfaction. However, scholarship welfare quality did not significantly affect satisfaction; this means that Hypothesis 3-2 was not supported. Second, satisfaction was positively related to commitment and recommendation intentions but it was negatively related to defection intentions. Third, commitment was positively related to recommendation intentions but it was negatively related to defection intentions. Conclusions - This study emphasizes the influence of education service quality on satisfaction in the long-term. In addition, this research has the following implications for university relationship management. First, the findings suggest that the various dimensions of education service quality have differing effects on satisfaction. In particular, lecture and facility welfare quality are found to be the most important factors in increasing the level of satisfaction. Therefore, university managers need to prioritize enhancing lecture quality and upgrading educational facilities. Second, satisfaction also improves through job assistance systems and opportunities for social interactions. Therefore, university managers should reinforce their job skills programs and should provide opportunities for social relationships to develop. Finally, it is important for university managers to take a relationship approach to maximizing relationship performance. Therefore, university managers should work to increase student recommendations and prevent their defections based on satisfaction and commitment.

The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.