• Computers and Concrete
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• 제14권6호
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• pp.727-743
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• 2014

The management of existing concrete bridges has become a major social concern in many developed countries due to the large number of bridges exhibiting signs of significant deterioration. This problem has increased the demand for effective maintenance and renewal planning. In order to implement an appropriate management procedure for a structure, a wide array of corrective strategies must be evaluated with respect to not only the condition state of each defect but also safety, economy and sustainability. This paper describes a new performance evaluation system for existing concrete bridges. The system evaluates performance based on load carrying capability and durability from the results of a visual inspection and specification data, and describes the necessity of maintenance. It categorizes all girders and slabs as either unsafe, severe deterioration, moderate deterioration, mild deterioration, or safe. The technique employs an expert system with an appropriate knowledge base in the evaluation. A characteristic feature of the system is the use of neural networks to evaluate the performance and facilitate refinement of the knowledge base. The neural network proposed in the present study has the capability to prevent an inference process and knowledge base from becoming a black box. It is very important that the system is capable of detailing how the performance is calculated since the road network represents a huge investment. The effectiveness of the neural network and machine learning method is verified by comparing diagnostic results by bridge experts.

• 한국도로학회논문집
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• 제15권3호
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• pp.177-189
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• 2013

PURPOSES: This study aims to suggest a proper left-turn treatment method for the bicycle traffic flow at four-legged intersections. METHODS: Four types of crossing methods are proposed and analyzed : (1) indirect left turn, (2) direct left turn, (3) direct left turn on a Bike Box, and (4) direct left turn on bike left turn lane. The VISSIM simulation tests were conducted based on forty-eight operation scenarios prepared by varying vehicle and bicycle traffic volumes. RESULTS : The results from the four-legged signalized intersections suggest that (1) the indirect left turn is appropriate when vehicle demand is high, (2) the direct left turn is efficient on most traffic situation but the safety is a concern, (3) the direct left turn on a Bike Box is appropriate when bicycle demand is high while vehicle demand is not, and (4) the direct left turn on a bike left turn lane is appropriate when both vehicle and bicycle demand are low. CONCLUSIONS : The direct left turn of bicycle provides more efficiency than the indirect left turn at the four-legged intersections but to apply the methods and to study more, advanced evaluation methods, related law, and insurance programs are needed.

• Management Science and Financial Engineering
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• 제16권3호
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• pp.21-47
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• 2010

Quantity discounts provide a practical foundation for supply chain inventory policies, improving the supplier's profit and reducing the buyer's inventory cost simultaneously. Traditional quantity-discount research, which deals with inventory coordination between a buyer and a supplier, is extended to a stationary stochastic environment. This research shows that the magnitude of the optimal discounts scheduled by the deterministic quantity discount models may not be large enough to cover the buyer's additional inventory stocking risks under uncertain conditions. As a result, the buyer's total inventory cost may often increase rather than decrease. In contrast, the proposed model allows the supplier to identify the discount level, which shares the buyer's amplified risk associated with temporary overstocking and ensures that both buyer and supplier benefit economically. The performance of the proposed model was tested in the continuous review environments via numerical experiments. The experimental results support the proposed method as a feasible alternative in coordinating inventory decisions under stochastic demand.

• Industrial Engineering and Management Systems
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• 제13권1호
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• pp.29-42
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• 2014

Extensive research has been conducted on supplier evaluation and selection as a strategic and crucial component of supply chain management in recent years. However, few articles in the previous literature have been dedicated to the use of fuzzy inference systems as an aid in decision-making. Therefore, this essay attempts to demonstrate the application of this method in evaluating suppliers, based on a comprehensive framework of qualitative and quantitative factors besides the effect of gradual coverage distance. The purpose of this study is to investigate the applicability of the numerous measures and metrics in a multi-objective optimization problem of the supply chain network design with the aim of managing the allocation of orders by coordinating the production lines to satisfy customers' demand. This work presents a dynamic non-linear programming model that examines the important aspects of the strategic planning of the manufacturing in supply chain. The effectiveness of the configured network is illustrated using a sample, following which an exact method is used to solve this multi-objective problem and confirm the validity of the model, and finally the results will be discussed and analyzed.

• 산업공학
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• 제25권4호
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• pp.422-430
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• 2012

In this article, we introduced the estimation method by 'Safety Integrity Level'(SIL) for the criterion of safety assurance and performed a case study on a flame scanner. SIL requires probabilistic evaluation of each set of equipment used to reduce risk in a safety related system. FMEDA(Failure Modes, Effects and Diagnostic Analysis) method is widely used to evaluate the safety levels and provides information on the failure rates and failure mode distributions necessary to calculate a diagnostic coverage factor for a part or a component. Basically, two parameters resulting from FMEDA are used for SIL classification of the device : SFF(Safe Failure Fraction) and PFD(Probability of Failure on Demand). In this case study, it is concluded that the flame scanner is designed to fulfill the condition of SIL 3 in the aspect of SFF and PFD.

• Journal of Forest and Environmental Science
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• 제19권1호
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• pp.108-123
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• 2003

1992년 리우회의 이후 국제적으로 환경자원의 중요성이 인식되면서 환경자원에 대한 가치를 정량화하고자 하는 움직임이 본격화 되었다. 우리나라 역시 이러한 국제적인 추세에 영향을 받으면서 1990년초부터 비시장재화의 가치를 평가하고자 하는 연구가 본격적으로 시작되었다. 또한 1999년에 예비타당성조사가 도입되면서 대규모건설사업 수행 전에 환경자원의 가치까지 고려한 비용편익분석이 실제로 이루어지고 있다. 하지만 환경자원에 대한 가치평가 방법이 아직 정립되지 못한 실정이다. 본 연구에서는 환경자원의 가치 평가를 위한 이론과 주요 평가 방법을 소개하였다. 이론에서는 환경자원의 가치를 수요함수와 생산함수차원에서 검토하고 이들 두 함수가 함께 고려된 시장에서 최적 수준을 도출하였다. 평가 방법에서는 시장의 특성에 따라 대표되는 평가 방법인 여행비용법, 만족가격법, 가상가치평가법을 소개하였다.

• 한국문헌정보학회지
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• 제21권
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• pp.141-168
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• 1991

The Purpose of this study is to explore and analyse ways of enhancing the effectiveness of reference service through reference evaluation. Marketing research technique combined with pre-evaluation theory was applied in this study to find out information for practice the service based on current concept of reference service. Aims and results of this study can be summarised as follows: First, the evaluation of effectiveness of reference service should be conducted for the purpose of finding out the ways of increasing user's satisfaction. Second, the policy evaluation was understood as the appropriated evaluation concept. The policy evaluation in principle coincides with reference service in sense that the satisfaction of public should have priority and hence be the criterion of the evaluation. Third, marketing research based on recently developed 'marketing concept', which concentrates all its efforts to meet user's demand and attempt to acquire the information for better marketing management of non-profit organization such as library, is examined to find out the evaluation method practically applicable to the pre-evaluation of reference service. In this study , conjoint analysis was adopted as the method of pre-evaluation about reference service. The Reference Room of the Central Library Yonsei University, was selected as the arget sample to find out the expected condition for the maximization of the user's satisfaction from the reference service. Based on this example study, the analysis indicates as the most desirable combination for reference service in terms of the user's satisfaction is following condition: the younger librarian with aimable personality who displays willingness In his/her assistance, plus as the method of reference service, sufficient and practical introduction to the reference materials available, plus immediate and satisfactory result of the service, and finally a library equipped with inter-library use system.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.30-40
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• 2007

The demand for light-rail construction projects has recently been increasing, and they are mostly supervised by private construction companies. Therefore, a private construction company that aim to raise gains from the operation of the facilities during the contract period greater than what they invested should b able to accurately calculate the costs from the aspect of Life Cycle Cost (LCC). In particular, a light-rail transit bridge that has a heavier portion from the aspect of the cost of light-rail transit construction requires a more accurate calculation method than the conventional LCC calculation method. For this, an LCC analysis model was developed and a cost breakdown structure was suggested based on literature review. The construction costs by shape of the upper part of a light-rail transit were calculated based on the cost breakdown system presented in this paper, and the cost generation cycle and cost unit price were collected and analyzed based on records on maintenance costs, rehabilitation and replacement. In addition, after forming some hypotheses in order to perform the LCC analysis, economic evaluation was conducted from the aspect of the LCC by using performance data by item.

• 보건행정학회지
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• 제30권1호
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• pp.131-138
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• 2020

The purpose of this study was to compare the health status of South Korea with those of Organization for Economic Cooperation and Development (OECD) countries and examine the trends. Position vAlue for Relative Comparison (PARC) was used as a gauge for comparison, and five sectors of the health care system were measured: demand, supply, accessibility, quality, and cost. The Mann-Kendall test was used as a statistical analysis method to examine trend of PARC values obtained from 2000 to recent years. According to the results, the demand, supply, accessibility, and quality sectors were higher than the OECD average, while the cost was lower than the average. However, there is a recent trend of sharp increases in health care costs. Some indicators: health employment, quality of primary care and mental health care were lower than the OECD average, and health determinants showed a worsening trend. Therefore, policy-makers need to take this into account and make efforts for sustainable health care.

• 디지털융복합연구
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• 제12권9호
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• pp.159-168
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• 2014

인터넷과 이동통신 기기의 발전으로 인해 개인의 경제활동에 관련된 인터넷뱅킹, 인터넷대출, 스마트폰등과 같은 이동통신기기를 이용한 모바일 뱅킹이 활성화되고 있다. 이에 따라 신종 범죄를 막기 위해 보안 시스템들이 새롭게 선보이고 있으며, 앞으로 보안 시스템의 시장은 날로 늘어날 것으로 보고 이에 따른 보안 시스템들에 대한 질적인 발전이 지속적으로 요구되고 있다. 따라서 보안시스템 제품의 시장이 지속적으로 성장할 것으로 예상되는 시점에서 보안 시스템의 품질평가 요구에 대응하기 위해 본 논문에서는 보안 시스템중의 네트워크 접근제어시스템 분야의 기반기술과 표준을 조사하고, 동향을 분석하여 관련 시스템의 시험과 평가방법을 제안하여 네트워크 접근제어시스템의 품질평가 방법과 체계를 제안하였다.