• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.859-862
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• 2002

In this paper, we consider a discrete-time two-phase queueing system. We derive the PCF of the system size and show that it is decomposed into two probabilty generating functions (PCFs), one of which is the PGF of the system size in the standard Ceo/G/1 queue. Based on this PGF, we present the performance measure of interest such as the mean number of customers In the system.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.121-130
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• 2009

This paper considers a six sigma project for reducing the cost copper of the cable materials in a electric wire company. The project follows a disciplined process of five macro phases: define, measure, analyze, improve, and control (DMAIC). A process map is used to identify process input variables. Three key process input variables are selected by using an input variables are selected by using an input variable evaluation table: large cable, plating, and a twisted pair. DOE is utilized for finding the optimal process conditions of the three key process input variables. The implementing result of this six sigma project is enable for reducing of the 2.8% copper materials.

• IE interfaces
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• v.18 no.2
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• pp.117-125
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• 2005

One of the primary means of achieving global competitiveness is to reduce the COPQ in our business units. Although the COPQ is not known precisely, it is known to be very high. Also, it may be underestimated by the hidden costs due to non-value added activities, such as potential lost sales, costs of redesign due to quality reasons, and extra manufacturing costs due to defects, etc. In any manufacturing or service operation, all actions and resource expenditures of a company should be focused on creating value for customers. Any activity or resource of not creating the value for customers could be regarded as waste, which consequently causes the COPQ. In this paper, a management system is developed for evaluating and reporting the COPQ in our business units, based on the Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) roadmap.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.481-485
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• 2015

Indonesian construction companies are currently facing high competition both among themselves and with global construction companies. In order to address this issue, the Government of Indonesia has enacted specific regulations and policies relating to the development and implementation of quality management systems (QMSs) ISO 9001 based in construction, acknowledging that the consistency of construction project quality requires a formal quality system as a guarantee to raise quality standards at all project stages. The research has been undertaken to examine the effectiveness of the regulations and policies against several key performance indicators (KPIs) of the ISO 9001 Indonesian construction companies. A comprehensive review of the relevant regulations and policies together with interviews with the Government and National Construction Services Development Board recommend possible additional guidelines and supporting quality system, which intends to measure contractors' project output against defined standards as well as to assess their performance among other similar service providers. The outcomes of the research contribute to the development of the Indonesian own construction industry quality measurement and assessment system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.2
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• pp.29-37
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• 2009

National R&D programs play an important role in the development of a country in this age of the knowledge economy. Since many numbers of R&D programs compete for limited resources such as national R&D budget, the R&D program evaluation problem is a challenging decision-making problem faced by decision makers that deal with R&D management. In this sense, DEA(Data Envelopment Analysis) has been regarded as one of the most widely accepted methods to measure the relative efficiency of productivity of R&D programs. DEA is a methodology to measure and to evaluate the relative efficiency of a homogeneous set of decision-making units(DMUs) in a process which uses multiple inputs to produce multiple outputs. However, the sample of the R&D programs could consist of two or more naturally occurring subsets, thus exhibiting clear signs of heterogeneity such as different objectives. In such situations, the fairness of DEA is limited, for the nature of the relative efficiency of a DMU is likely to be influenced by its membership in a particular subset of the sample. In this study, we propose a methodology AI-DEA(attainment index DEA) allowing for reflecting decision maker's subjective judgement on difference among different subsets of R&D programs which have heterogeneous objectives. This methodology combines AHP and Delphi in order to decide the attainmnet index of each DMU for each outputs, and apply them to DEA model. We illustrate the proposed approach with a pilot evaluation of 13 programs involving 6 different subsets of Korean National R&D programs and compares the results of the original DEA model and AI-DEA model.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.62-69
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• 2019

Korean shipbuilding companies have taken many efforts for safety over the years by developing Health, Safety & Environment (HSE) Management Systems, Procedures, Training, and studying Programs for prevention of incidents. As a result, the shipbuilding industry has succeeded in reducing overall injury rates. Nevertheless, the industry also noticed that incident rates are still not at zero and more importantly, serious injuries and fatalities are still occurring. One factor that may be attributing to this is the lack of managing potential severity during incident investigations, most incident investigations are implemented based on the actual result. Generally, each shipbuilding company develops their customized incident investigation programs and these are also commonly being focused on actual result. This study aimed to develop a shift in strategy toward safety to classify the criteria of potential severity from any incidents and manage that to prevent any recurrence or causing any serious injuries or fatalities in the shipbuilding industry. Several global energy companies have already developed potential severity management tools and applied them in their incident investigations. In order to verify the necessity of improvement for current systems, a case study and comparative analysis between a domestic shipbuilding company and several global energy companies from foreign countries was implemented and comparison of two incident investigation cases from specific offshore projects was conducted to measure the value of a potential severity system. Also, a checklist was established from the data of fatalities and serious injuries in recent 5 years that occurred in Korea shipbuilding industry and a proposal to verify high potential incidents in the incident investigation process and comparative analysis between the assessment by appling proposed checklist and the assessment from a global energy company by using their own system was implemented. As a measure to prevent any incidents, it is required to focus on potential severity assessment during the incident investigation rather than to only control actual result. Hence, this study aims to propose a realistic plan which enables to improve the existing practices of incident investigation and control in the shipbuilding industry.

• Journal of Korean Society for Quality Management
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• v.50 no.3
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• pp.387-405
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• 2022

Purpose: This study aims to develop a communality model to measure the service quality that the customers encounter on face-to-face and non-face-to-face automobile insurance before and after insurance purchase. Methods: For these purposes, we conduct a five-step program to develop a comprehensive communality model to measure service quality except insurance purchase channels. Results: As a result, we find five communality factors: value-added service for automobile maintenance, value-added service for drivers, quickness, dispatch service, and convenience of the service process. And the relative importance of service quality factors was in the order of value-added service for drivers, the convenience of the service process, quickness, and dispatch service, respectively. Conclusion: This study developed the opportunities to enhance service quality to attract customers. And it contributes to the academic literature by reporting the industry-specific service quality model, which maintains a theoretical gap in the online and offline automobile insurance industry.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.329-335
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• 2014

Collaborative filtering has been popular in commercial recommender systems, as it successfully implements social behavior of customers by suggesting items that might fit to the interests of a user. So far, most common method to find proper items for recommendation is by searching for similar users and consulting their ratings. This paper suggests a new similarity measure for movie recommendation that is based on genre interest, instead of differences between ratings made by two users as in previous similarity measures. From extensive experiments, the proposed measure is proved to perform significantly better than classic similarity measures in terms of both prediction and recommendation qualities.

• Journal of Information Management
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• v.41 no.3
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• pp.45-66
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• 2010

The purpose of this study is to develop service quality measurement model(DL-SQI model) which are able to measure objectively service quality of digital libraries in Korea and to measure user perceived service quality performance with DL-SQI model. This study also investigates the influence of service quality on customer satisfaction and customer loyalty. Before measurement, two principal rules and indicator formula were made to measure the service quality. Finally service quality of three digital libraries selected as samples was measured and analyzed in various points of view. It was developed a DL-SQI Consequences Model and testified it through path analysis using structural equation model.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.