• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권7호
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• pp.2434-2454
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• 2021

This paper developed the software testing factory-cloud testing platform (STF-CTP) to address the software compatible issues in various smart devices. Software developers who only require uploading the application under test (AUT) and test script can test plenty of smart devices in STF-CTP. The challenge for the cloud test platform is how to optimize the resource and increase the performance in the limited resource. This paper proposed a new scheduling mechanism and a new process of the system operation which is based on the OpenStack platform. We decrease about 40% memory usage of OpenStack server, increase 3% to 10% Android device usage of STF-CTP, enhance about 80% test job throughput and reduces about 40% test job average waiting time.

• Journal of Nutrition and Health
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• 제15권2호
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• pp.107-118
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• 1982

In order to obtain the information on the meal behaviors and the status of using university cafeteria, the survey was conducted through the questionaries to 2,425 students (Male : 48.8%, Female : 51.2%) of 9 universities throughout Korea. While most of the male students were having breakfast regularly (M : 70.7%, F : 52.7%), the female students enjoyed snacks for lunch (M : 21.8%, F : 55.0%) or between meals (M : 42.0%, F : 81.0%). Most of the subjects thought that skipping breakfast had bad influence on health. The male students had their lunch at the cafeteria more frequently than the female students. And the students in the universities without off campus dining facilities used cafeteria often. The students in the university-managed cafeteria also used the facilities more often than the rental situation. Other lunch habits in the case of not eating at the cafeteria were ‘bring lunch’ and ‘eat off-campus’. The main reasons for not eating at the cafeteria were ‘too crowded’(28.3%) and ‘waiting in long time'(28.0%). Only 4.9% of the students were satisfied with the menu, but the nearly half (42.3%) showed unsatisfaction largely because of the limited choice of menu Students pointed out the taste and the nutritional quality of the menu should be improved firstly. Another strong complaint was waiting in line.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3121-3135
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• 2015

Owing to the increase in consumption of multimedia content and the improvement of device capacity, user demand for high-quality content has increased. However, it is difficult to transport such large amounts of content over the existing broadcasting network with limited bandwidth. To provide high-definition broadcasting, some studies suggest methods of transporting multimedia over heterogeneous networks after encoding content hierarchically. MPEG Media Transport (MMT), standardized by Moving Picture Experts Group (MPEG), is a solution that enables large-volume media transport over heterogeneous networks such as digital broadcasting networks and packet-switched networks. In the case of delivering a scalable encoded video over different networks, synchronization of each stream is an important issue. MMT defines a synchronization scheme, but does not contain sufficient functions to implement it. In this paper, we propose a synchronization scheme for media streams that are encoded hierarchically, divided into layers, and transported over heterogeneous networks. We implement our scheme using MMT and HTTP, and experimented using three encapsulated video streams with different durations. As a result, we show that the proposed scheme can reduce the waiting time to display high-quality video, relative to Dynamic Adaptive Streaming over HTTP-Scalable Video Coding (DASH-SVC) by requesting segments of enhanced layers after calculating the transmission time. Additionally, we find out that the selection of durations have a relation to the characteristics of the video.

• 대한산업공학회지
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• 제34권1호
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• pp.108-121
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• 2008

Dispatching rule for parallel machines with multi product is proposed in this paper, In current market,customer's request for higher quality is increasing, In accordance with such demand, manufacturers are focusingon improving the quality of the products. Such shift in production objective is risky. The possibility ofneglecting another important factor in customer satisfaction increases, namely due dates. From the aspect ofimproving quality, frequency of product assignment to limited number of high performance machines willincrease. This will lead to increased waiting time which can incur delays, In the case of due date orientedproduct dispatch, Products are assigned to machines without consideration for quality. Overall deterioration ofproduct quality is inevitable, In addition, Poor products will undergo rework process which can increase delays.The objective of this research is dispatching products to minimize due date delays while improving overallquality. Quality index is introduced to provide means of standardizing product quality. The index is used toassure predetermined quality level while minimizing product delays when dispatching products. Qualitystandardization method and dispatching algorithm is presented. And performance evaluation is performed withcomparison to various dispatching methods.

• 한국통신학회논문지
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• 제41권12호
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• pp.1811-1813
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• 2016

DCF (Distributed Coordination Function)는 송신노드들이 경합 윈도우 중에서 임의로 송신 대기 시간을 결정함으로써 노드 사이의 채널 경합을 분산적으로 해결한다. 그러나 경합 윈도우의 최대 크기는 제한적이므로 송신 노드의 수가 많아지는 경우 송신 충돌 확률이 증가한다. 본 논문에서는 이와 같은 문제를 해결하기 위해 소수 게임 (MG: Minority Game) 이론을 기반으로 전송제어 기법을 제안한다. 각 노드는 MG 규칙에 따라 타 노드와의 정보 교환 없이 자신의 이득을 극대화하기 위해 분산적으로 송신 여부를 결정한다. 모의실험을 이용한 정량적 성능 평가를 통해 제안 기법은 DCF의 성능을 송신 충돌 확률 측면에서 향상시킨다는 것을 보였다.

• Journal of Preventive Medicine and Public Health
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• 제24권4호
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• pp.473-484
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• 1991

Hospitals have been very susceptable to changes in external environment. Accordingly, they have been experiencing great financial difficulty due to low insurance rates and increasing competition. As a remedy, hospitals have attempted to use computer in a strategic manner. Such system is called strategic information system(SIS), and order communication system(OCS ) is an example of SIS in hospital setting. While OCS has known to be effective in reducing waiting time for outpatients, many hospitals are reluctant to introduce this system mainly because there are no real data or methods for justifying the cost of the system. Cost-benefit analysis has been traditionally used for such purpose, but this method deals with limited portion of benefits and therefore not very useful for analyzing the economic feasibility of SIS. In this paper, information economics tools which expand cost with value was used to analyze the economic feasibility of OCS. To assist the analysis, financial simulation model was developed using simulation package, called IFPS(Interactive Financial Planning System).

• 한국실내디자인학회논문집
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• 제15권1호
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• pp.106-112
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• 2006

Buildings undergo changes by various factors according as pass at time. Due to that social requests and issues form one common sense of value and this would influence the architect's design intention. In fact, the form and function of buildings have coped with transition of the common sense of value by each times. Hospital architecture is also changed in function, scale and technology since, Kwanghyewon which was the first western style hospital in Korea was established in 1885. It is changing that the social needs for hospital which was a basic function of healing to laying emphasis on the function of precaution. According to this, the change of hospital spaces means that it can promote healing environment which is expanded from the modern concept of isolation, accommodation and urban sanitation. These changed concepts were adopted limited areas in hospitals at first however, nowadays they are expanding to other areas. So, this is caused to make the image of the hospital. From this point of view, Entry space is an example to show the changes. This study is intended to determine the overall space structure of entry area and to classify and analyze the difference.

• 한국산업보건학회지
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• 제33권2호
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• pp.171-187
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• 2023

Objectives: Aircraft cabin cleaning work is characterized by being performed within a limited time in a narrow and enclosed space. The objective of this study was to evaluate the exposure levels to dust, ultra fine dust(PM2.5) and black carbon(BC) among aircraft cabin cleaners. Methods: Active personal air sampling for respirable dust(n=73) and BC(n=47) was conducted during quick transit cleaning(cabin general and vacuum-specific) and seat cover replacement and total dust and PM2.5 were area-air-sampled as well. Also, size distribution of particle was identified with the cleaning workers targeted. Dusts were collected with PVC filters using gravimetric analysis. The concentration of PM2.5 and the particle size distribution were measured with real-time direct reading portable equipment using light scattering analysis. The concentration of BC was measured by aethalometer(filter-based real-time light absorption analysis instrument). Results: The geometric mean of respirable dust was the highest at vacuum cleaning as 74.4 ㎍/m³, following by replacing seat covers as 49.3 ㎍/m³ and cabin general cleaning as 47.8 ㎍/m³ . The arithmetic mean of PM2.5 was 4.83 ~ 9.89 ㎍/m³ inside the cabin, and 28.5~44.5 ㎍/m³ outside the cabin(from bus and outdoor waiting space). From size distribution, PM_2.5/PM₁₀ ratio was 0.54 at quick transit cleaning and 0.41 at replacing seat covers. The average concentration of BC was 2~7 ㎍/m³, showing a high correlation with the PM2.5 concentration. Conclusions: The hazards concentration levels of aircraft cabin cleaners were very similar to those of roadside outdoor workers. As the main source of pollution is estimated to be diesel vehicles operating at airports, and it is necessary to replace older vehicles, strengthen pollutant emission control regulations, and introduce electric vehicles. In addition, it is necessary to provide as part of airport-inftastructure a stable standby waiting space for aircraft cabin cleaners and introduce a systematic safety and health management system for all workers in the aviation industry.

• 한국항행학회논문지
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• 제20권1호
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• pp.86-92
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• 2016

최근 사람이 다수 붐비는 지역에 스마트 폰이나, 태블릿 등을 바로 충전할 수 있는 태양광 모듈이 설치되어 서비스를 제공하고 있다. 하지만 설치비용이 높아 이용인원이 적은 지역에 설치 할 경우 비용측면에서 부담이 되며, 협소한 지역에는 설치가 어려운 문제점이 존재한다. 본 논문에서는 이와 같은 문제를 해결하기 위해 국가에서 제공하는 데이터와, 실제 환경에서 수집한 데이터를 이용하여 각 지역에 해당 서비스를 제공받는 사람에 대한 정보를 분석 한 후 대기시간 및 태양광 충전시간을 고려하여 환경에 맞는 최적의 전력을 수집 및 제공하는 시스템을 제안하였다. 실험결과 수집전력이 충전전력량보다 상회하여 충전이 지연되지 않았으며, 약 95분경에 스마트 폰의 전력을 모두 충전할 수 있음을 확인하였으며, 버스 대기시간인 10분에서 20분 사이에 스마트 폰이 한 대일 경우 약 50%가량을 충전할 수 있으며, 여러 대일 경우 약 20%가량을 충전할 수 있음을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제22권3호
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• pp.35-41
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• 2013

본 연구는 생산 공정 간 버퍼 제약이 있는 flow shop 시스템에 활동기간 기반 애로공정 발견 기법을 적용하여 그 타당성을 분석하였다. 생산 시스템에는 보통 생산성을 저하시키는 1개 또는 1개 이상의 애로공정이 존재한다. 전통적인 애로공정을 발견하는 기준으로 공정의 대기 시간이나 대기 공정의 길이 또는 공정의 이용률이 자주 활용된다. 애로공정은 다른 공정작업을 대기 상태로 만들어 전체적으로 시스템의 생산성을 저하시키는 공정으로 공정 시간과 기계의 고장 및 수리 시간의 확률적인 특성으로 인하여 애로공정은 생산과정에서 수시로 다른 공정으로 변환된다. 어떤 공정이 언제 활동기간으로 변화하는 정보를 이용하여 애로공정을 발견하는 기법을 범용 시뮬레이션 언어 AweSim에서 구현하였다. 시뮬레이션 결과, 활동기간 기법과 단독 및 변환 애로공정 기간 비율 기법이 전통적인 기법과 비교하여 애로공정을 발견하는데 효과적인 것으로 나타났다. 간단한 flow shop 모형을 대상으로 얻은 결과이지만 복잡한 시스템에도 적용될 수 있을 것으로 기대되며 애로공정 개선을 통한 생산시스템 가용 자원의 효과적인 배치는 생산성을 향상시키는데 기여할 것으로 사료된다.