• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.89-97
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• 2011

Traditional quality control for manufacturing or service sector is not suitable for the quality control of a project as the project is one-time task constrained by time, cost, and quality. To meet the internal and external customers' requirements, quality costs approach to the project will be effective. Hence, we propose PONC (price of nonconformance) estimation procedure and a mathematical model, which are focused on activity-based prevention in the execution step and warranty step of EPLC (extended project life cycle). This procedure and model will help project manager develop preventive action plan for project quality costs minimization from nonconformance risk activities and PONC estimates information.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.661-663
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• 2019

4차 산업 혁명의 핵심기술로 손꼽히는 AR을 이용하여 캠퍼스 이용에 유용한 정보를 제공한다. 사물인식, 위치기반의 AR구현 방식을 사용하며 AR네비게이션 방식으로 입체화된 길안내 정보를 제공한다. AR을 통해 제공되는 정보는 이미지 혹은 텍스트가 될 수 있고 3D모델, 미디어 그리고 이들의 모든 조합의 형태를 취할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.568-570
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• 2019

위치 기반 서비스를 중점으로 교내의 각종 정보들을 제공하는 챗봇시스템을 구축한다. 교내 공지사항, 학사정보와 실시간 전화 연결 서비스 및 자연어 처리를 기반으로한 다양한 정보들을 제공한다.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.331-341
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• 2015

Gasoline prices vary across Korea. Some gas stations charge higher prices, while others charge lower prices. In this paper, we try to find: why gasoline prices differ markedly across regions. We empirically estimate the determinants of gas prices by incorporating supply side factors as well as demand side factors into the empirical model. Empirical results show that both location-specific factors and store-specific factors affect gas prices. Concentration of competing stores, store brands, ownership of gas stations, and self-service availability influence gas prices. In addition, the availability of other customer services such as convenience stores, car wash, and auto repairs affects gas prices.

• Journal of applied mathematics & informatics
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• v.39 no.1_2
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• pp.173-196
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• 2021

This paper treats a retrial queue with phase type retrial times and a threshold type-policy, where each server is subject to breakdowns and repairs. Upon a server failure, the customer whose service gets interrupted will be handed over to another available server, if any; otherwise, the customer may opt to join the retrial orbit or depart from the system according to a Bernoulli trial. We analyze such a multi-server retrial queue using the recently introduced threshold-based retrial times for orbiting customers. Applying the matrix-analytic method, we carry out the steady-state analysis and report a few illustrative numerical examples.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.105-109
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• 2022

In this study, the cause of the acceleration failure of Hyundai Motor's 2.0-liter CRDi engine was analyzed. We tried to find problems through MDA (Measuring Data Analyzer) based on data such as vehicle speed, air intake, and air-fuel ratio obtained during the actual driving process. As a result, it was analyzed that the failure of the EGR valve exceeded the NOx emission standard and caused a decrease in engine output. Through this study, it is possible to reduce the time and cost of unnecessary maintenance and repair, and it is expected that a rapid cause analysis will be possible in the case of new failure diagnosis in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.507-509
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• 2022

In order to collect vehicle internal diagnostic data, it is necessary to collect diagnostic data of ECU (Electronic Control Unit) included in various automotive parts. Diagnostic communication can be used to collect diagnostic data of ECU. In this paper, the method of collecting diagnostic data according to ECU function through standard diagnostic communication and the diagnostic communication module were analyzed. Among the standard modules of AUTOSAR, a standard for automotive electronics used by many automobile manufacturers, the diagnostic communication module was studied, and the process of diagnostic data processing through ECU was studied.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1160-1163
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• 2021

DOOH(Degital Out of Home) advertisement market is developing steadily, and the case of use is also increasing, In advertisement market, personalized services is actively being provided with technological development. On the other hand, personalized services are difficult to be provided in DOOH and are p rovided by only personal information, not feelings. This study aims to construct personalized DOOH se rvices by using AI facial expression recognition and suggesting a solution optimized for interaction bet ween user and services by providing healing and advertisement.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.585-592
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• 2016

This study was conducted to analyze the gap between importance and satisfaction of university foodservice attributes as well as to assess customer satisfaction with university foodservice establishments. All statistical analyses were conducted using the SPSS package program (ver. 20.0) for t-test, ANOVA, and Importance-Performance Analysis (IPA). A total of 619 valid responses were used for the data analysis. The results of this study are as follows: the composition of respondents was 53.5% males and 46.5% females. Exactly 85.5% of respondents ate lunch at least five times a week at the on-campus foodservice. The favorite lunch menus of Chinese university students were Chinese food (91.8%), followed by Western food (3.5%), Korean food (2.2%), and Japanese food (1.5%). According to the results of IPA, foodservice selection attributes that were priorities for improvement were food taste, food freshness, menu variety, waiting time for meal, and toilet cleanliness. In addition, five satisfaction factors were extracted by exploratory factor analysis. According to the results of one-way ANOVA, 'physical environment' and 'service quality' factors showed significant differences according to the students' grades and the frequency of eating lunch at on-campus foodservice. On the other hand, 'food quality and menu' and 'convenience and price' factors showed significant differences according to meal cost. In conclusion, in order to enhance customer satisfaction of on-campus foodservice, foodservice managers should offer a varied menu at reasonable prices and improve food quality.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.164-172
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• 2015

Seoul subway plays an important part for the public transportation service in Seoul metropolitan area. As the subway system is typically a closed environment, frequent air pollution problems occurred and passengers get malhealth impact. Especially particulate matters (PM) is well known as one of the major pollutants in subway environments. The purpose of this study was to compare the concentrations of $PM_{10}$ and $PM_{2.5}$ in the Seoul subway system and to provide fundamental data in order to management of subway system. $PM_{10}$ and $PM_{2.5}$ samples were collected in the M station platform and tunnel of Subway Line 4 in Seoul metropolitan and in an outdoor location close to it from Apr. 21, 2010~Oct. 27, 2013. The samples collected on teflon filters using $PM_{10}$ and $PM_{2.5}$ mini-volume portable samplers and PM sequential sampler. The PM contributions were $48.6{\mu}g/m^3$ (outdoor), $84.6{\mu}g/m^3$ (platform) and $204.8{\mu}g/m^3$ (tunnel) for $PM_{10}$, and $34.6{\mu}g/m^3$ (outdoor), $49.7{\mu}g/m^3$ (platform) and $83.1{\mu}g/m^3$ (tunnel) for $PM_{2.5}$. The $PM_{10}$ levels inside stations and outdoors are poorly correlated, indicating that $PM_{10}$ levels in the metro system are mainly influenced by internal sources. In this study, we compared PM concentrations before and after operation of ventilation and Electrostatic Precipitator (EP). Despite the increased PM concentration at outdoor, $PM_{10}$ concentration at platform and tunnel showed the 31.2% and 32.3% reduction efficiency after operation the reduction system. The overall results of this study suggest that the installation and operation of the ventilating system and EP should have served as one of the important components for maintaining the air quality in the subway system.