• Journal of the Korean Society of Combustion
• /
• v.8 no.2
• /
• pp.7-16
• /
• 2003

The transfer of air pollutants between passenger room and service room in train are investigated by the computational analysis. The effects of service room temperature, inlet velocity, initial concentration and heating are studied. The flow induced by the difference of density between two rooms is found to take the major role in transfer of polluted air. Low temperature of service room enhances the polluted air flow into passenger room along the floor. Exhaust fan above the door between two rooms is not effective for this case. Strong inlet flow is found to suppress polluted air flow from service room. The heating of passenger room can promote air pollution.

• Journal of Information Technology Services
• /
• v.12 no.2
• /
• pp.85-101
• /
• 2013

The wide spread of smartphones and the growth of the number of internet users are reshaping the SNS (Social Network Service). Merging into other service areas and creating new business models with high profits, SNS is no more a service simply providing personal connections. Now SNS has positioned itself as a service platform. SNG (Social Network Game) is a new outcome utilizing SNS as a game platform and showing a rapid growth rate in a short period of time. The number of SNG users is expected to increase steadily. In this study, we examine whether SNG user motivations lead to flow experience and future intention to use. For that purpose, we conducted a survey with smartphone users. The results indicate that flow experience functions as a mediator and user motivations indirectly affect intention to use through flow experience. This paper concludes with discussions on findings and suggestions for future research.

• Journal of the Optical Society of Korea
• /
• v.18 no.5
• /
• pp.466-471
• /
• 2014

An asynchronous optical packet-switching (AOPS) node with load-balancing capability can achieve better performance in reducing the high packet-loss ratio (PLR) and time delay caused by unbalanced traffic. This paper proposes a novel dynamic load-balancing algorithm for an AOPS node with limited buffer and without wavelength converters, and considering the data flow distribution and service levels. By calculating the occupancy state of the output ports, load state of the input ports, and priorities for data flow, the traffic is balanced accordingly. Simulations demonstrate that asynchronous variant data packets and output traffic can be automatically balanced according to service levels and the data flow distribution. A PLR of less than 0.01% can be achieved, as well as an average time delay of less than 0.46 ns.

• Journal of Information Technology Services
• /
• v.11 no.1
• /
• pp.247-272
• /
• 2012

Social Network Service(SNS) is a kind of advanced Internet service that acts as personal media. This study was intended to find out the structural relationships among factors affecting the usage of social network services by extending the Technology Acceptance Model(TAM). For this purpose, the variable 'Flow' was first integrated into the TAM in order to understand the internal motivations of users. And then the external factors of SNS usage were derived from the perspective of users, contents, and media side of SNS, and finally the dependent variable was set with the intention of sustainable use. Then these factors were carefully integrated into a structural model. We expect the findings of this study will be very helpful for the internet marketing professionals, SNS developers, and the others.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.22 no.2
• /
• pp.121-132
• /
• 2019

Recently as development of internet, Service based on World Wide Web is rapidly growing. According to this, Importance for suitability of web service is emphasized by increased user with development of technique of web service. Geospatial information field included with River Geospatial information(HydroG-OneFlow) has been doing that many study about web service which center of IT, However study about test of web service is lacking of situation. Accordingly, verification should be carried out to determine the performance of Web services with the Web services implementation HydroG-OneFlow. Performance & stability test are verified that HydroG-OneFlow for Apache Jmeter of open source and conformability & interoperability test are verified for StyleCop. Result of performance is that if users are increase the number of 500, average responses time is about two seconds. and Result of reliability is that if users are increase the number of 500, decrease about 0.2%. it is verified that conformability and interoperability test to swelled about reliability of HydroG-OneFlow. Through that It will be compensate for the implementation of seb service and vulnerability of HydroG-OneFlow.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04a
• /
• pp.310-312
• /
• 2000

명시적인 자원 할당과 스케줄링에 의해 QoS를 제공 할 수 있는 방안으로 RSVP가 제안되었으나 내부 구조 변경이나 확장성의 문제를 내포하고 있다. 그래서 IETF에서는 차등 서비스(Differentiated Service)를 이용하여 서비스 영역을 확장하려는 연구가 활발히 진행중이다. DiffServ는 확장성을 고려하여 RSVP와 같은 개별 flow에 대한 QoS 제공이 아닌 flow들의 집합(aggregated)으로 차등적인 서비스를 제공하는 방법이다. 본 논문에서는 aggregated flow로 서비스를 제공할 때 불특정 flow에 대한 QoS 손실을 막기 위해 Token Bucket Meter 처리 전에 사전 모니터링에 의해 자원공유의 공정성과 처리 속도를 향상시킬 수 있는 TC(Traffic Conditioner)를 설계, 구현하여 다수 subnetwork에서의 flow가 자원을 공정하게 공유함을 결과로 보였다.

• Annual Conference of KIPS
• /
• 2000.04a
• /
• pp.538-543
• /
• 2000

DS(Differentiated Service)에서는 RSVP와 같이 개별 flow에 대한 QoS제공이 아닌 flow들의 집합(aggregate)으로 차등적인 서비스를 제공하는 방법이다. 확장성을 고려한 이러한 방안은 광역백본망 에서와 같이 수천, 수만의 flow들에 대해 서비스를 제공하고자 할때 flow들을 집합(aggregate)화 하여 차등적인 서비스를 제공하고자 하는 것은 매우 큰 의미가 있다고 할 수 있다. 하지만 DS에서는 Token Bucket 방법을 사용하여 트래픽 스트림을 측정하는 이유로 불특정 flow에 대해 심각한 QoS손실을 야기할 수 있다. 본 논문에서는 자원공유의 공정성을 기여하기 위해 Traffic Conditioner에서 사전 모니터링 방법을 사용하고 이 모니터링 결과를 Weighted Fair Queuing의 파라메터로 사용하여 잉여 자원을 효율적으로 사용하는 방안을 제시한다.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.614-619
• /
• 2007

The importance of simulation of plastic flow in the injection mold is increasing as the parts are more complex, but the small-scale enterprises can't afford to invest for the infra individually. CAE (Computer Aided Engineering) service was naturally born based on these needs. This paper presents the engineering collaboration model between the large and the small/medium enterprises in the field of injection molds. Based on the engineering collaboration hub and CAE service, small-scale enterprises could research the necessary technology and develop the proper products. The analysis results of CAE are provided by the integrated visualization system on the web. This paper also deals with the delivery shorting process of CAE service for electric/electronic parts which should meet the needs of customers as soon as possible.

• Quality Improvement in Health Care
• /
• v.7 no.2
• /
• pp.244-261
• /
• 2000

Background : In order to cope with changes in the management environment at hospitals, increased interests are drawn in patient foodservice system on Continuous Quality Improvement Activity as the method of approaching a quality food service and effective management. Thus, as a part of this activity, this study was conducted to evaluate job flow improvement that was already performed and the results of that process at the dietetic department of a university hospital, focusing on improving management. Method : On February 15 of 1998. the dietetic department formed a job flow-improvement to decide on the priority of job flow improvement, and prepared specific action strategies and schedule of the priority: after a 5 month process period, job improvement achieved on June 15. 1998. Also, economic achievement of the task was evaluated through labor productivity analysis and cost-benefit analysis. Results : The patient food service system which was managed decentralized at the present hospital was centralized, some steps of the food service process were integrated, and quality of patient food was improved. Also, as a solution of the problems expected when conducting job flow improvement was made on food service equipments and utensils. The result of evaluating the job flow improvement that labor productivity improved by 18.2% compared to before the improvement and the result of the analysis of cost-benefit showed that Benefit-Cost (B/C) ratio was 2.22. showing financial merit on the investment. Conclusions : Continuous Quality Improvement Activity needs to be initiated and conducted in the future in various areas of hospital foodservice system in order to actively adopt to ever changing hospital management environment. In order to achieve this goal, many researches and more efforts need to be put in by people in charge of hospital food service management, and interests and support are needed from hospital policy makers.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.6
• /
• pp.1032-1039
• /
• 2015

Service function chaining(SFC) defines the creation of network services that consist of an ordered set of service function. A multiple service function instances should be deployed across networks for scalable and fault-tolerant SFC services. Therefore, an incoming flows should be distributed to multiple service function instances appropriately. In this paper, we formulate the flow distribution problem in SFC aiming at minimizing the end-to-end flow latency under resource constraints. Then, we evaluate its optimal solution in a realistic network topology generated by the GT-ITM topology generator. Simulation results reveal that the optimal solution can reduce the total flow latency significantly.