• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 춘계학술대회논문집
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• pp.129-134
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• 2003

In this paper, we determine optimal reduction in the lead time and setup cost for some stochastic inventory models. And we propose more general model that allow the backorder rate as a control variable. We first assume that the lead time demand follows a normal distribution. And we assume that the backorder rate is dependent on the length of lead time through the amount of shortages. The stochastic models analyzed in this paper are the classical continuous and periodic review policy models with a mixture of backorders and lost sales. For each of these models, we provide a sufficient conditions for the uniqueness of the optimal operating policy. We also develop algorithms for solving these models and provide illustrative numerical examples.

• 가족자원경영과 정책
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• 제12권4호
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• pp.15-33
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• 2008

The purpose of this ethnography is to describe and analyze the employment and substitutional use of daily help for the household work. Ten housewives and one educator of daily help from Gwangju City were interviewed with an unstructured questionnaire. They experience many difficulties from this daily help employment and use, even though they gain some basic help from their service. The diversity of the routes to seek out this daily help means that there is no proper route. And the daily help's sudden quit causes many realistic and psychological problems. Frequent disagreement between the user's demand and help's implement comes from communication failure. Three different management patterns of daily help were issued ; 'conservative-dominant', 'rational-mandatory', 'powerless-dependent'.

• Industrial Engineering and Management Systems
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• 제15권4호
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• pp.354-363
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• 2016

Due to uncertain environment, various parameters such as price, queuing length, warranty, and so on influence on inventory models. In this paper, an inventory-queuing-pricing problem with continuous review inventory control policy and batch arrival queuing approach, is presented. To best of our knowledge, (I) demand function is stochastic and price dependent; (II) due to the uncertainty in real-world situations, a fuzzy programming approach is applied. Therefore, the presented model with goal of maximizing total profit of system analyzes the price and order quantity decision variables. Since the proposed model belongs to NP-hard problems, Pareto-based approaches based on non-dominated ranking and sorting genetic algorithm are proposed and justified to solve the model. Several numerical illustrations are generated to demonstrate the model validity and algorithms performance. The results showed the applicability and robustness of the proposed soft-computing-based approaches to analyze the problem.

• 한국태양에너지학회 논문집
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• 제33권6호
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• pp.77-84
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• 2013

Degree-day method is very simple but essential index to estimate heating and cooling energy demand in buildings. It has been neglected, however, for the simplicity so it is difficult to find any DB for south Korean cities. Even meteorological department of S. Korea doesn't report the data officially. In this study, current methods that are being used in many countries are investigated and used to calculate degree-days of 35 south Korean cities with 30 years(1981~2010) historical data. The calculation result indicates that the error among 4 major methods are dependent on how daily or hourly temperature are treated in the calculation and how balance point temperature is defined. The errors of the methods are no larger than 6% relative to hourly degree-day method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권1호
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• pp.177-190
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• 2011

The purpose of this study is to explore the determinants of actual demand for wireless broadband (WiBro) services in Korea. To this end, this study identifies conceptual definitions of diverse latent variables and determines the significance of the causal relationship between independent and dependent variables. It then presents the nomadic user concept by testing the moderator effect. This study also proposes a revised Unified Theory of Acceptance and Use of Technology (UTAUT) model, which is an appropriate model for wireless communication services and users' attributes. Prior research has concentrated exclusively on the Technology Acceptance Model (TAM) based on future potential users. Compared to previous studies, the current research model and analysis results are useful in not only academic but also industry contexts.

• Earthquakes and Structures
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• 제22권2호
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• pp.147-155
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• 2022

Regarding the importance of seismic pounding, the available standards and guidelines specify minimum separation distance between adjacent buildings. However, the rules in this field are generally based on some simple assumptions, and the level of confidence is uncertain. This is attributed to the fact that the relative response of adjacent structures is strongly dependent on the frequency content of the applied records and the Eigen frequencies of the adjacent structures as well. Therefore, this research aims at investigating the separation distance of the buildings through a probabilistic-based algorithm. In order to empower the algorithm, the record-to-record uncertainties, are considered by probabilistic approaches; besides, a wide extent of material nonlinear behaviors can be introduced into the structural model by the implementation of the hysteresis Bouc-Wen model. The algorithm is then simplified by the application of the linearization concept and using the response acceleration spectrum. By implementing the proposed algorithm, the separation distance in a specific probability level can be evaluated without the essential need of performing time-consuming dynamic analyses. Accuracy of the proposed method is evaluated using nonlinear dynamic analyses of adjacent structures.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.544-548
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• 2015

As urbanization increases in UAE, the demand for housing and infrastructures also grows. The challenge is to continue to build but in a different way considering more energy-efficient sustainable buildings. Producing a sustainable design is highly dependent upon effective participation among the diverse parties involved. In the construction industry in the UAE, these parties are fragmented due to the multistage nature of construction projects and multidisciplinary participants, particularly during the design stage. The decisions made during this stage have an extensive impact on subsequent stages of a project's life cycle. Having a sustainability expert during the design stage is important and the awareness of sustainability requirements by all design participants is of equal importance. In this research, recent advances in information technology are used to develop an information model that will improve the sustainability of building during the design stage. An information framework for storing design information and sustainability performance criteria is developed, allowing design participants to collaborate in an integrated environment. This research is expected to help designers produce sustainable designs for building projects.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.3956-3972
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• 2023

The floor response spectrum (FRS) is used to evaluate the seismic demand of equipment installed in nuclear power plants. In the conventional design practice of NPP structure, the FRS is simplified using the lumped-mass stick model (LMSM), assuming the floor slab as a rigid diaphragm. In the present study, to study the variation of seismic response in a floor, the FRSs at different locations were generated by 3-D finite element model, and the response was compared to that of the rigid diaphragm model. The result showed that the FRS significantly varied due to the large opening in a floor, which was not captured by the rigid diaphragm model. Based on the result, seismic fragility analysis was performed for the anchorage of a heat exchanger, to investigate the effect of location-dependent FRS disparity on the high confidence low probability of failure (HCLPF).

• The Korean journal of internal medicine
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• 제39권4호
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• pp.547-554
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• 2024

The incidence and mortality of colorectal cancer (CRC) have decreased through regular screening colonoscopy, surveillance, and endoscopic treatment. However, CRC can still be diagnosed after negative colonoscopy. Such CRC is called interval CRC and accounts for 1.8-9.0% of all CRC cases. Most cases of interval CRC originate from missed lesions and incompletely resected lesions. Interval CRC can be minimized by improving the quality of colonoscopy. This has led to a growing interest in and demand for high-quality colonoscopy. It is important to reduce the risk of CRC and its associated mortality by improving the quality of colonoscopy. In this review article, we provide an overview of colonoscopy quality indicators, including bowel preparation adequacy, the cecal intubation rate, the adenoma detection rate, the colonoscopy withdrawal time, appropriate polypectomy, and complication of the procedure. Because colonoscopy is a highly endoscopist-dependent procedure, colonoscopists should be well-acquainted with quality indicators and strive to apply them in daily clinical practice for the prevention of CRC.

• 동아시아경상학회지
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• 제12권3호
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• pp.11-23
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• 2024

Purpose: The plant industry is a key order-taking industry that leads national industrial development through convergence and integration with various industries in all value chains from planning and marketing to financing, design and engineering, purchasing, construction, and operation and maintenance (O&M). Research design, data and methodology: The Korea government has been actively promoting overseas plant market development support projects to support large and public enterprises and medium and small enterprises. Results: The Korea government are working with the industry and the government so that the Korean plant industry can establish itself as a key driving force that provides the foundation for low-carbon and energy transition that our times demand and makes our world a better place to live. Conclusion: A high value-added industry that brings enormous profits and international fame to exporting countries. Korea is highly dependent on trade, should recognize the plant industry as a key national export sector.