• Journal of Biosystems Engineering
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• 제35권1호
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• pp.15-20
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• 2010

Tractor PTO output and fuel consumption rate under the korean paddy and various paddy operations were measured and analyzed, in which all the measurements were accomplished by the OECD tractor test codes and the collected information will be utilized for defining tractor energy efficiency class and its test methods. Tractor PTO performance tests were conducted under full-load, part-load and various engine RPMs with part-load at the engine laboratory, while the paddy operations were dry land plowing, wet and dry land rotary tilling and wet land preparation under various soils. As a whole, the rated tractor outputs were ranged from 17% to 100% in the various tillage and land preparation operations, however, the loads for the paddy operations of 1,700 to 2,000 rpm were very close to the OECD tractor load distribution thus it would be appropriate to adopt OECD tractor test codes to measure energy consumption efficiency of tractor.

• 한국경영과학회지
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• 제40권1호
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• pp.117-128
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• 2015

An organization must restructure itself once it makes outsourcing decisions. Outsourcing is a strategy that a company adopts to direct internal efforts into strengthening its core business processes while contracting other companies for strategically less critical tasks thereby improving organizational production efficiency, and the strategy inevitably involves organizational restructuring. While public service organizations have increasingly embraced outsourcing as well, only a handful of studies analyze the change in efficiency from organizational restructuring. Therefore, this study uses Stochastic Frontier Analysis (SFA) to test whether efficiency improved in Korea Expressway Corporation's restructured branch offices. Korea Expressway Corporation evaluated and grouped its branches based on road extensions management, traffic volume, the number of snow days, road deterioration, and the number of junctions to differentially allocate its personnel and budget. The extent of efficiency improvement in each group was compared, and results show that inefficiency did not exist in any of the groups. The efficiency index among the three group categories was similar across the board; 9 offices in the A-group with its expanded personnel and budget had an efficiency index of 0.954, 12 offices in the B-group with unchanged personnel and budget conditions had an index of 0.950, and 12 offices in the C-group with reduced personnel and budget had an index of 0.937. SFA facilitates efficiency analyses because it does not require pre-restructuring data. This study is easy to apply in practice and empirically tests efficiency improvement in organizational restructuring based on data collected from all the branch offices in Korea Expressway Corporation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.24-31
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• 2000

This paper evaluates the efficiency of Korea National Railroad on the basis of revenues from 1980 to 1999. There was a significant inefficiency in this organization due to operating at an decreasing return to scale area. Although Korean Railroad in 1990s has made a great effort, his performance is still low. Consequently, it is important to insure substantiality of operations than to expand business area in order to finally improve the efficiency, in particular the revenue efficiency, of the Korea Railroad.

• 한국경영과학회지
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• 제40권1호
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• pp.75-89
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• 2015

In recent years, attention to the high debt ratio in public institutions has pushed the government to make efforts in reducing the debt ratio. However, in order to stimulate the economy, the government needs drastically innovative measures that reduce debt by improving efficiency rather than moderate approaches that focus solely on debt reduction. Despite this need, no study has yet systematically analyzed the overall efficiency of domestic public institutions and identified the source of inefficiencies in each public entity. Therefore, largely two research questions are examined. First, this study compares the efficiency levels by types of public institutions. Second, this study identifies the cause of inefficiencies in each public institution and proposes directions for improving efficiency. Based on a 5-year data of 302 public institutions published in public business information systems and organizational websites from 2009 to 2013, Data Envelopment Analysis (DEA) was performed. The input variables include the number of employees and total costs while the output variables include sales and net income. Reflecting the characteristics of public institutions, the input-oriented CCR model and input-oriented BCC model were utilized. Analysis results are as follows. First, market-oriented public institutions showed the highest efficiency while fund management quasi-governmental agencies showed the highest inefficiency. Second, scale efficiency score was measured by applying the CCR model and the BCC model on the organizations with the lowest efficiency level, fund management quasi-governmental agencies. Based on these analysis results, the source of inefficiency and detailed directions for improvement were proposed for Decision Making Units (DMUs) with low CCR and BCC scores.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 춘계학술발표논문집
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• pp.167-173
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• 2006

Deinking is a series of unit operations designed to detach ink from cellulose fibers and separate the dispersed ink from the pulp slurry. Deinking chemicals are process aids that enable expensive mill equipment used in these unit operations to operate more efficiently - often much more efficiently. We propose the blended deinking agent with cellulolutic enzymes and synthetic collector in deinking pulp of conventional alkaline method. The deinking efficiency of old news print in alkaline pH was enhanced with enzyme treatments. The brightness of deinked pulp was increased with less residual ink particles and yield of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method. Enzymes in biomass were use to Chemical Deinking for reduce environment pollution through surfactant and improve surfactants. examining into compatibility Enzymes and surfactants, these new materials are studied efficiency of deinking efficiency.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.1845-1850
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• 2006

적절한 벤치마킹 대상의 선정은 조직 계획 및 통제에 있어 중요한 요소로 인식되고 있으며, 이에 대한 많은 연구가 이루어져 왔다. 특히, 조직의 상대적 성과 평가와 이를 바탕으로 벤치마킹 대상을 결정하는 DEA(data envelopment analysis)의 출현은 벤치마킹에 대한 연구를 증대시켜왔다. 하지만, 벤치마킹 대상 선정은 기술적 생산 가능성 측면 외에도 조직의 정책적 고려, 관리적 우위 그리고 외부 제약 등을 고려해야 한다. 따라서 수리적 결과에 바탕을 둔 기술적 생산 가능성만을 가지고 벤치마킹 대상을 제공하는 현재의 DEA 접근 방법에는 한계가 있다. 즉, 고려하는 모든 대상을 기반으로 한 global efficiency 관점에서 제공하는 해가 비 효율적 조직 입장에서는 바람직하지 않을 수도 있다. 이에 따라 본 연구에서는 local efficiency 개념을 도입하여, 다양한 관점에서 벤치마킹 대안들을 살펴 볼 수 있는 방법을 제공하고자 한다. 이는 다음과 같은 과정에 의해 수행된다. 먼저, DEA를 이용하여 비교하고자 하는 모든 DMU(decision making unit)의 투입/산출물을 바탕으로 각 DMU의 효율성 값과 비효율적 DMU의 참조집합 (reference set)을 도출한다. 다음으로, 도출된 참조집합이 조직 운영 관점에서 적절한 벤치마킹 대상이며, 이러한 목표를 달성할 수 있는가를 평가한다. 이때 도출된 벤치마킹 대상이 적절하다면 분석과정을 종료하고, 적절하지 않을 경우 다음과 같은 추가적인 분석을 수행한다. 우선, 각 참조 집합을 중심으로 DMU를 그룹핑하고, 각 그룹별로 효율성 값 및 참조집합을 도출한다. 이때 도출된 효율성 값이 local efficiency 값에 해당된다. 다음으로, 참조 집합 그룹을 중심으로 도출된 비효율적 DMU의 참조집합이 적절한 벤치마킹 대상인가를 판단한다. 적절한 벤치마킹 대상을 도출하였으면 분석을 종료하고, 그렇지 않을 경우 적절한 벤치마킹 대상을 도출할 때까지 추가적인 분석과정을 반복한다. 제안한 방법을 통하여 조직은 기술적 생산 가능성 외에도 다양한 조직 운영 관점에서 적절한 벤치마킹 대상을 선정할 수 있으며, 이에 따른 목표를 수립할 수 있을 것으로 기대한다. 또한 더 나아가 global efficiency 관점에서 효율적 조직이 되기 위하여 단계적인 벤치마킹 대상 선정과 이에 따른 목표를 수립하는데도 유용하리라 판단된다.

• 한국국방경영분석학회지
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• 제33권2호
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• pp.61-73
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• 2007

본 연구의 목적은 미래 기술예측에 사용되는 TFDEA(Technological Forecasting with Data Envelopment Analysis)의 문제점을 살펴보고 이의 개선방향을 찾아 주력전차의 기술예측 문제에 적용해 보는 것이다. 기존의 TFDEA는 복수의 DMU(Decison Making Unit)를 효율적 DMU로 판정하는 DEA(Data Envelopment Analysis)의 특성상 실제로는 그다지 효율적이지 않은 DMU까지 포함해서 기슬예측을 수행함으로써 예측 결과의 정확도가 저하될 수 있다. 본 연구에서는 DEA의 확장된 개념을 적용하여 평가 대상 DMU에 대한 순위를 산정한 후 이를 토대로 기술 예측을 시행하는 방법을 검토해 보았다. 이를 위해 일반적인 DEA기반의 순위선정 방법 중 대표적인 Super-efficiency, Cross-efficiency, CCCA(Constrained Canonical Correlation Analysis)을 TFDEA에 결합 적용하고 이들을 비교해 보았다. 제시된 방법을 주력 전차의 미래 기술 예측 문제에 적용한 결과 CCCA를 이용한 순위선정방법이 실제 실현된 기술 수준과 비교했을 때 통계적으로 가장 작은 오차율을 보였다.

• 경영과학
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• 제31권4호
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• pp.135-150
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• 2014

This paper analyzes the operational efficiency of 91 individual retail stores in Seoul by a two-step procedure. In the first step, a data envelopment analysis (DEA) model is used to identify the efficiency scores. Three inputs (store size, number of items, and number of employees) and two outputs (sales and number of customers) are used for the efficiency measurement. In the second step, a Tobit regression model is used to identify the drivers of efficiency. DEA efficiency scores are used to test hypotheses on the impact of five independent variables, namely store age, number of items per store size, number of items per employee, trade area index, and number of competitors. Results of the Tobit analysis show that number of items per store size, number of items per employee, and number of competitors play a significant role in influencing the operational efficiency of retail stores. Managerial implications of the study are discussed.

• 한국군사과학기술학회지
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• 제15권3호
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• pp.306-314
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• 2012

This paper proposes a new system to maximize efficiency of Air Base Protection Operations through the development of location identification software. The Wibro-based location identification system for Air Base Protection Force offers Blue Ground Force digitalized character message which is not exposed to enemy. Also, it is possible to automatically provide the location of Blue Ground Force to Air Base Ground Operations Center. The test result proves that this system is very helpful when Air Base Protection Force executes Air Base Protection Operations.

• 한국경영과학회지
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• 제33권2호
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• pp.75-86
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• 2008

A remarshalling is one of the operational strategies considered importantly at a port container terminal for the fast ship operations and heighten efficiency of slacking yard. The remarshalling rearranges the containers scattered at a yard block in order to reduce the transfer time and the rehandling time of container handling equipments. This Paper deals with the rearrangement problem, which decides to where containers are transported considering time value of each operations. We propose the mixed integer programming model minimizing the weighted total operation cost. This model is a NP-hard problem. Therefore we develope the heuristic algorithm for rearrangement problem to real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost. For the sensitivity analysis of configuration of storage and cost weight, a variety of scenarios are experimented.