• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.23-40
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• 2014

This paper measures the operational efficiency of domestic online game companies and analyze its trends and patterns by using data envelopment analysis (DEA). DEA is a non-parametric approach to measuring the relative efficiency of decision-making units (DMUs) with multiple inputs and outputs. 14 online game companies are selected as DMUs and three inputs (number of employees, capital and asset) and three outputs (sales, operating profit and net profit) are selected as DEA variables. First, the output-oriented BCC model and super-efficiency model are employed to measure the static operational efficiency of the online game companies from 2003 to 2012. We also conduct the dynamic analysis with DEA window model to capture the trends of their operational efficiency influenced by internal and external environmental changes. The results are expected to provide fruitful implications for strategic decision making of online game companies and policy making for the online game industry.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.3
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• pp.35-49
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• 2017

The main objective of this paper is to empirically analyze the efficiency effects of mergers on Korean pharmaceutical firms and suggests managerial or policy implications for managers or policy makers. This study selects non-merging control firms close to the size of merging firms, as well as a set of merging firms, and measures the effects of mergers on efficiency three years before and after the merger using the non-parametric data envelopment analysis (DEA) method. To compare the differences of efficiency means among several groups, Wilcoxon rank sum test or Wilcoxon signed rank test is used. It showed that the long-term effects after the merger appeared partially. Furthermore, it was observed that there was no difference statistically in the efficiency between merging and non-merging firms. Also, there was no difference statistically in the efficiency between the pre- and post-merger periods. In conclusion, there was not any observed synergy effect through group (or affiliated) mergers between affiliates or related mergers for Korean pharmaceutical firms.

• Journal of the military operations research society of Korea
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• v.36 no.2
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• pp.85-106
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• 2010

Recently, government is endeavoring for Defense Ministry unit's efficiency improvement according as requires low cost, high effectiveness continuously about public sector. But, by real condition that measuring analysis about logistical corps'(LOG) efficient operation is not, this study was done to present method to estimate efficient management availability of logistical corps(LOG). Presents choosing variable that is suitable in Quartermaster Corps' efficiency estimation for this through existing virtue study investigation, and takes advantage of DEA (Data Envelopment Analysis) technique that divert in public sector efficiency measurement, I wish to present plan for inefficient organization's efficiency improvement after evaluate efficiency to Quartermaster Corps.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.4
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• pp.273-279
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• 2021

Winglets are specialized wingtip devices to reduce induced drag, and they have been installed on Boeing-made aircraft since the 1980s, Airbus has also developed a winglet named 'Sharklet' since 2009 and has started providing them as an option to the A320 Family. The winglet has the effect of improving take-off performance, reducing fuel consumption, increasing payload, and increasing flight distance by reducing the induced drag generated at the tip of the wing. The purpose of this study is to analyze the actual flight data of the sharklet-installed and non-sharklet-installed models of the A321 aircraft to verify the fuel efficiency improvement due to the winglet installation, and to analyze the economic analysis accordingly. Through this, it can be used to determine the winglet installation when introducing an aircraft or to make a decision for upgrading the existing aircraft. To this end, a case study on the aerodynamic characteristics and effects of the winglet installation was conducted, and the economic analysis was verified.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.617-620
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• 2000

In this paper, we show an application of constraint logic programming to the operation scheduling on machines in a job shop. Constraint logic programming is a new genre of programming technique combining the declarative aspect of logic programming with the efficiency of constraint manipulation and solving mechanisms. Due to the latter feature, combinatorial search problems like scheduling may be resolved efficiently. In this study, the jobs that consist of a set of related operations are supposed to be constrained by precedence and resource availability. We also explore how the constraint solving mechanisms can be defined over a scheduling domain. Thus the scheduling approach presented here has two benefits: the flexibility that can be expected from an artificial intelligence tool by simplifying greatly the problem; and the efficiency that stems from the capability of constraint logic programming to manipulate constraints to prune the search space in an a priori manner.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.94-102
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• 2012

In this paper, an interactive planning and scheduling framework are proposed for optimising operations from pits to crushers in ore mining industry. Series of theoretical and practical operations research techniques are investigated to improve the overall efficiency of mining systems due to the facts that mining managers need to tackle optimisation problems within different horizons and with different levels of detail. Under this framework, mine design planning, mine production sequencing and mine transportation scheduling models are integrated and interacted within a whole optimisation system. The proposed integrated framework could be used by mining industry for reducing equipment costs, improving the production efficiency and maximising the net present value.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.957-964
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• 2024

Universities own several campuses and many buildings within the campuses. During the operation & maintenance phase, some of the buildings have architectural components and MEPFs that must be maintained. In the authors' study, university campus Facility Manager uses paper drawings and paper documents for operations and maintenance of MEPFs, and building components, which are managed by human power. In this study, As-Built 3D model of school buildings, was developed by 3D scanning with MatterPort Pro2 camera. A digital twin of the school building was developed from integrating the As-Built 3D model with a COBie Sheet information that defines the building and facility components for FMr. This developed digital twin was used to verify the efficiency of conventional Facility Management (FM) operations. The specific procedures are as follows. (1) Conducted an interview survey on FM of conventional university campuses to organize the current operations. (2) The following building items, which are annual inspection items, were extracted from the conventional FM operations being performed, Speakers, fire alarms, fire doors, guide lights, air conditioning, and fire extinguishing equipment. (3) Since these items listed above are currently documented in different formats, the authors organized them into a database using COBie format. (4) The components of the organized COBie format and the As-Built 3Dmodel were integrated to complete the digital twin. (5) To verify the effectiveness of the digital twin, experiments were conducted on information search in current FM operations and workflows using the digital twin. (6) We also verified the effectiveness of the AS-Built 3D model by comparing between the As-Built 3D model and the BIM model. Finally, we discussed how process innovation through digitalization of FM operations contributes not only to the improvement of daily operations, but also to the productivity improvement of university management.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.2
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• pp.242-252
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• 2008

The objective of this study was to suggest a new efficiency measurement indicator for evaluating the menu management efficiency of decision making units(DMUs) in contract-foodservice operations and to determine the relationship between the DEA(data envelopment analysis) menu efficiency score and menu factors. The results of applying DEA revealed relatively efficient types of service and frequency of meals. The efficient service was shown as a self-service type that operates Monday to Saturday. The considered menu factors included meal price, food cost per meal, meal counts, number of menu items, use of favorite menu use, forecasting error, accuracy of ordering, ratio of inventory, ratio of food loss, use of processed foods and use of prepared vegetables are considered. There were significant correlations between the DEA score and meal price, meal counts, number of menu items, ratio of food loss, accuracy of ordering and use of processed foods respectively. According to the regression results, menu price had a positive influence on the DEA menu efficiency score, and food cost per meal and the use of prepared foods had negative influences respectively.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.2
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• pp.49-61
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• 2017

The study on the efficiency analysis of Korean automobile parts companies is mostly based on the calculation of the size of output such as sales. However, the performance indicators such as sales, operating profit, and net profit are directly related to the cost structure, and this cost structure is affected by changes in the company's asset structure and capital structure. As a result, it is necessary that efficient capital procurement should be done at the same time to create efficient management performance through proper investment. In this study, we aim to measure the efficiency of asset and capital procurement compared to the sales figures, such as sales, generated by 33 primary suppliers who supply parts to Hyundai Kia Motors. For this purpose, this study proposed a DEA cross analysis model that can simultaneously measure efficiency in terms of input assets and capital procurement based on the same management performance when analyzing the efficiency of domestic auto parts companies.

• Journal of the Korean Operations Research and Management Science Society
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• v.10 no.1
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• pp.1-8
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• 1985

By introducing the concept of reliability of parallel systems the set covering. A branch-and-bound algorithm is developed and illustrated by a numerical example. The procedure has been coded and its computational efficiency is studied.