• Journal of the Korean Operations Research and Management Science Society
• /
• v.24 no.3
• /
• pp.1-11
• /
• 1999

We consider the problem of determining the spare inventory level for a multiechelon repairable-item inventory system. Our model extends the previous results to the system which has an inventory at the central depot as well as bases. We develop an optimal algorithm to find spare inventory leveis, which minimize the total expected cost and simultaneously satisfy a specified minimum service rate. The algorithm is tested using problems of various sizes to verify the efficiency and accuracy.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.17 no.3
• /
• pp.171-180
• /
• 1992

This paper proposes a solution approach to linear problems with many constraints of variable upper bound (VUB) type. This type of constraints are commonly found in various scheduling type problems for which tighter bounds are essential to achieve an efficiency in enumeration. An analytical framework based on factorization is adopted to devise a solution approach to the problem and extend it for more generalized VUB problem (GVUB). This research shows why the VUB type constraints are amenable to the factorization and gives a unified approach to generalized upper bound(GUB) problems, VUB problems and GVUB problems. Implementation issues are also included.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.05a
• /
• pp.664-667
• /
• 2004

In nuclear power plant, the main control room(MCR) plays a leading and important role, so it is the core to have its design well operater-centered, both physically and cognitively. This paper especially analyzes focusing on lighting MCR environment and shows alternatives. It will lead to improve work efficiency and to care operator's sight. In conclusion, reducing operator's stress, fatigue and increasing safety, comfort.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2008.10a
• /
• pp.95-103
• /
• 2008

본 논문에서는 업무할당방식이 효율성에 미치는 영향을 분석함으로써, BPM 업무환경에서 효율성을 증진시키기 위한 방법론을 모색한다. 이를 위해, 업무할당방식을 프로세스 실행시에 사용자를 할당하는 동적할당과 프로세스 모델링시에 결정하는 정적할당으로 구분하여 BP효율성 관점에서 상호 비교한다. 지금까지 이런 업무 할당방식이 업무효율성에 어떤 영향을 미치는지에 대한 연구가 없었으며, 본 논문은 cycle time 척도에 대해서 이들 업무할당방식을 비교 분석한다. 이러한 비교 분석의 결과는 상용 BPM를 도입하여 운영하는 기업에게 업무효율성을 높이는 가이드라인을 제시할 수 있다.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.10a
• /
• pp.661-664
• /
• 2004

본 연구는 DEA기법을 이용하여 14개의 국내 은행의 상대적 효율성을 평가하였다. 효율성 평가에 있어서 은행을 중개기관 접근방법에서 평가하였으며, 투입물과 산출물을 선정하는 데 있어서 신탁계정과 은행계정별로 구분하여 연구를 수행하였다. 또한 규모의 효율성을 평가하기 위해 CCR모형과 함께 BCC모형을 이용하여 효율성을 평가하였다. 분석결과 신탁계정과 은행계정의 효율성은 차이가 있었으며, 대부분의 은행들이 DRS의 규모의 효율성에 있는 것으로 나타났다.

• Korean Management Science Review
• /
• v.32 no.3
• /
• pp.37-54
• /
• 2015

This paper suggests energy efficiency which can be the foundation on corporate profit and effective energy management following by change of global climate and of energy-related regulations. Using comparable financial information and information related to energy use, an DEA (Data Envelopment Analysis) model has been used to identify energy efficiency with DMU (Decision Making Unit)s which are companies subjected to reduce greenhouse gas emission in 2009. Through this research, different from existing researches, environmental variables which can influence on energy efficiency are identified. The results show as follows. First, most of companies follow IRS, which means scale of economy exists among units so that they have more opportunity to increase efficiency by increasing scale of inputs. Second, this research identified that depending on the difference of environmental characters such as the emission structure and the size of companies, energy efficiency of the companies turns out differently.

• Korean Management Science Review
• /
• v.27 no.2
• /
• pp.45-54
• /
• 2010

In this paper we analyze the effects of loading-unloading environments on the efficiency of freight railroad stations using a two-stage procedure for efficiency model estimation. And from the results we explore a way for efficiency improvement of freight railroad stations. Two-stage procedure is composed of data envelopment analysis and regression analysis. The results show that we could expect efficiency improvement through the government"s effort to make railway stations to be strategic position. Furthermore, they advocate policy-makers that efficiency can be improved by simplifying the kinds of freight items and increasing the scale.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2001.10a
• /
• pp.395-398
• /
• 2001

Studies on quantity discounts have been in two directions since Buchanen[1] published that suppliers provide quantity discounts for price discrimination and for channel efficiency. The quantity discounts for price discrimination have been treated in economics. On the contrary, the quantity discounts for channel efficiency have been studied in production management with assumptions and focuses different from economics. In this paper, the differences in each area are analyzed and purchasing situations that supplier's motivation on quantity discounts occurs is analyzed and the purchasing situations for two-stage quantity discounts are specified. In conclusion, we suggest that suppliers can enhance channel coordination through two stage quantity discounts in these purchasing situations.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.25 no.4
• /
• pp.81-91
• /
• 2019

Purpose: Since infectious disease hospitals are premised on emergency operations, the operational efficiency of secured personnel, equipment, facilities, etc. is relatively low. In order to increase such normal operational efficiency, it is necessary to flexibly operate facilities and operations during normal and emergency times. The purpose of this study is to suggest the architectural planning method focusing on the space composition and circulation of the regional infectious disease hospital which can increase the operational efficiency in the private hospitals. Methods: Through literature review, functional requirements of infectious disease hospitals were identified, and related personnels inter-views and field surveys were conducted to understand the spatial composition and circulation requirements of infectious disease hospitals. Results: Through the complete separation between the negative pressure zone and the general zone, even when the negative pressure zone is completely closed, the general zone should be operated separately to achieve operational efficiency. In addition, the separation of the negative pressure zone and the general zone should simultaneously consider the optimal space configuration and movement for each function while the zone settings match in the floor plan of each department and the overall cross-sectional configuration of the hospital. Implications: Infectious disease hospitals intended to be installed in private hospitals should not apply excessive space just for safety reasons and should plan to ensure their operational efficiency.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.306-320
• /
• 2021

To ensure safe port operations around the world, it is important to solve mooring problems. In particular, the many ports that face open seas have difficulties with long-period waves. As a countermeasure, the installation of a breakwater is proposed for mooring safety. However, this often cannot be put into practice because of financial issues. Instead, port terminals control berthing schedules with weather forecasting. However, mooring problems remain unsolved, because of inaccurate wave forecasting. To quantify the current situation, numerical simulations are presented with ship motions, fender deflections, and rope tensions. In addition, novel simulations for mooring ropes are proposed considering tension, friction, bending fatigue, and temperature. With this novel simulation, the optimal mooring method in terms of safety and economic efficiency was confirmed. In terms of safety, the optimal mooring method is verified to minimize dangerous mooring situations. Moreover, the optimal mooring method shows economic benefits and efficiency. It can help to reinforce the safety of port terminals and improve the efficiency of port operations.