• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.45-52
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• 2018

We consider the busy period of an M/G/1/K queueing system with queue-length-dependent overload control policy. A variant of an oscillating control strategy that was recently analyzed by Choi and Kim (2016) is considered: two threshold values, $L_1({\leq_-}L_2)$ and $L_2({\leq_-}K)$, are assumed, and service rate and arrival rate are adjusted depending on the queue length to alleviate congestion. We investigate the busy period of an M/G/1/K queue with two overload control policies, and present the formulae to obtain the expected length of a busy period for each control policy. Based on the numerical examples, we conclude that the variability and expected value of the service time distribution have the most influence on the length of a busy period.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.316-316
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• 2016

HyGIS는 DEM 기반의 수문지형처리를 중심으로 다양한 모형을 연계할 수 있도록 구성된 S/W 모음이다. 이는 한국건설기술연구원을 비롯한 다수의 기관 및 연구원들이 노력한 성과물이다. 본 연구는 기존 HyGIS 연구과정에서 도출된 성과물의 실용화 사업화를 위한 방안을 연구하였다. 이를 위하여 S/W 테스팅, 오픈소스 도입, 클라우드 컴퓨팅으로 나누어 접근하였다. 먼저 S/W의 테스팅에 있어서 기존 개발 소스코드는 블랙박스 테스트 방식의 동등 클래스 분할, 경계 값 분석 등 일부 모듈에 대한 단위 테스트와 제한적인 통합테스트가 수행된 바 있다. 보다 체계적인 테스트 단계로서 화이트박스 테스트 개념 중 문장/분기/조건 커버리지에 대하여 검토하였으며, 실제 소스코드 중 핵심 구간에 대한 적용 및 정량화를 통하여 현 수준을 객관적으로 진단하였고 보완 방안을 도출하였다. 오픈소스 적용을 위하여 QGIS, MapWindow 등 공간정보 분야의 최신 오픈소스 모듈을 비교 검토하였다. 적용 단계는 이를 기존 HyGIS S/W에 반영시키는 과정이며, S/W 관점에서는 컴포넌트 모듈의 대체라고 표현될 수 있다. 대규모의 전환 비용이 발생되므로 적용 후보에 대하여는 기능적 측면 뿐만 아니라 마이그레이션 비용과 중장기적인 유지보수 비용을 고려한 검토가 이루어 졌다. 한편 오픈소스 기술의 적용은 단순히 구성 요소 원가절감 측면만이 아닌, 중장기적 유지보수 체계 도모 및 지속가능한 생태계로의 전환에 더 큰 의의가 있다. 마지막으로 클라우드 컴퓨팅 기술의 적용 분야이다. HyGIS 입력 Data의 공급을 위한 인프라로서 자체 구축 인프라가 아닌 IaaS 클라우드인 Blob Storage 및 CDN을 시험 적용하였다. 클라우드를 활용함으로써 초기 비용을 최소화하고 합리적 비용으로 유연한 확장이 가능한(Scale Out, Scale Up) 구조를 취하게 되었다. 또한 입력 Data 공급 서버를 위한 Storage 측면만이 아니라 S/W의 배포에 있어서도 클라우드 컴퓨팅 기술을 활용하고자 시도하였다. 클라우드 기술을 활용하여 HyGIS S/W가 설치된 VM(Virtual Machine)자체를 임대하는 방식으로 시험 구성 되었다. VM에 대한 RDP 프로토콜 Access에 있어서 IP기반 접근 제어를 통하여 보안을 강화하는 방안을 실험하였으며, ISO 27001, ISO 27018 등 관련 보안 규정에 부합하는 서비스 제공이 가능하도록 검토하였다. 이러한 클라우드 VM방식 서비스를 통하여 Package형 S/W 뿐만 아니라 Subscription 방식의 서비스 제공 방식을 병행할 수 있다. 사용자에게는 S/W 설치 및 H/W Lock 구비 과정이 생략되는 이점이 있다.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.49-61
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• 2011

In recent, library is considered as an integrated knowledge convergence center that can respond to various requests about information service of users. Therefor it is necessary to establish a novel information system based on information communications technologies of the era. In other words, it is currently required to develop mobile information service available in portable devices such as smart phones or tablet PCs, and to establish information system reflecting cloud computing, SaaS, Annotation, and Library 2.0 etc. In this paper we design and implement a library information system using collective intelligence and cloud computing. This information system can be adapted for the varieties of mobile service paradigm and abruptly increasing amount of electronic materials. Advantages of this concept model are resource sharing, multi-tenant supporting, configuration, and meta-data supporting etc. In addition it can offer software on-demand type user services. In order to test the performance of our system, we perform an effectiveness analysis and TTA authentication test. The average response time corresponding to variance of data reveals 0.692 seconds which is very good performance in timing effectiveness point of view. And we detect maturity level-3 or 4 authentication in TTA tests such as SaaS maturity, performance, and application programs.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.82-100
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• 2024

Due to the intensifying global technological competition, the strategic and economic importance of intellectual property such as patents as intangible assets is increasing. The purpose of this study is to understand the current status of patent innovation in the service industry and to derive the characteristics and implications of patent innovation in the service industry. To this end, this study conducted an investigation and analysis to understand the characteristics of patent innovation in the service industry based on the data from the business activity survey. The proportion of patent companies in the service industry, characteristics of each service industry, proportion of each service industry, and the number of patent rights holdings were analyzed. In addition, the trend of patent changes in the service industry was investigated. The service industry was compared and analyzed with other industries based on the results of the analysis of patent innovation in the service industry. In particular, the service industry was divided into four types in terms of the rate of increase in the proportion of patent companies and the ratio of patent holing companies, and the types were derived. Based on the analysis results, the characteristics of patent innovation in the service industry were presented. As a result of the study, the proportion of patent holding companies in the service industry was lower than that of other industries, and the gap with other industries was widening, showing that the patent innovation of service companies is lower than that of other industries. The average number of patents held by service industry companies was lower than that of other industries, and the increase rate of the number of patent rights held was also lower than that of other industries, widening the gap. Patent innovation in the service industry can be divided into four quadrants in terms of the rate of increase in the proportion of patent holding companies and the proportion of patent holding companies, and it has been studied that the service industry needs policy support suitable for the characteristics of patent innovation in the quadrant to which the individual service industry belongs.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.27-35
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• 2015

We analyze an M/G/1/K queueing system with queue-length dependent service and arrival rates. There are a single server and a buffer with finite capacity K including a customer in service. The customers are served by a first-come-first-service basis. We put two thresholds $L_1$ and $L_2$($${\geq_-}L_1$$ ) on the buffer. If the queue length at the service initiation epoch is less than the threshold $L_1$, the service time of customers follows $S_1$ with a mean of ${\mu}_1$ and the arrival of customers follows a Poisson process with a rate of ${\lambda}_1$. When the queue length at the service initiation epoch is equal to or greater than $L_1$ and less than $L_2$, the service time is changed to $S_2$ with a mean of $${\mu}_2{\geq_-}{\mu}_1$$. The arrival rate is still ${\lambda}_1$. Finally, if the queue length at the service initiation epoch is greater than $L_2$, the arrival rate of customers are also changed to a value of $${\lambda}_2({\leq_-}{\lambda}_1)$$ and the mean of the service times is ${\mu}_2$. By using the embedded Markov chain method, we derive queue length distribution at departure epochs. We also obtain the queue length distribution at an arbitrary time by the supplementary variable method. Finally, performance measures such as loss probability and mean waiting time are presented.

• The Journal of Sustainable Design and Educational Environment Research
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• v.8 no.1
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• pp.11-22
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• 2009

School is a basic and the most fundamental facility of city planning just like other basic public facilities including the village office. Every plan is established on the basis of school. However, the problems such as the population reduction resulting from the nuclear family-zation and low birth rate, employment and welfare of the aged people resulting from "the old aged society", and the infant nursing and education resulting from a rapid increase of the working couples become notable and accordingly more requirements are being made. Reflecting this trend, the concept and operation system should be changed. Up to now, the BTL projects of the educational facilities are gaining a reputation of being efficient in terms of national budget running, but at the same time receiving negative reputation in terms of budget saving under the civil creativity and efficiency. Through upgrading the private sector investment projects into the BTO+BTL system and further into the BTO(Build Transfer Operate), we can accomplish the original goals of the private sector investment projects, and can make the education budget operation more efficient, and can greatly improve the education environments. However, we should not underestimate in this process that these facilities should not negatively affect the education environments. In any situation, the owners of schools are students.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.793-798
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• 2009

In this paper, the performances of implementation real-time book search service of government library using OpenAPI. Since 2000, each self-government made a governmnt library for local resident because of policies to encourage reading. Each self-government library services book perusal and lend free for local resident. In current system local residents visit to a library for lending, returning and reading books. And each library run by a self-governing administration provides their own homepage for searching service as well as booking. For each services are not unified, however, it is not easy for lenders to search and lend these enormous books which are spread each library. Accordingly, we present a plan which using organization of every system established now in each library as it is, for a scheme of database by libraries' efficient unification and search, a network of TCP/IP and application which connects each library's database, servicing which uses Open API a check books through real time accessing Database.

• International Commerce and Information Review
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• v.14 no.4
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• pp.563-582
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• 2012

In this paper, UPnP Network SaaS model has been studied. Currently, this model of UPnP Network and the trade mission is being used by outsourcing. From now on, the introduction of new trading systems and existing systems and the commercialization of this model as a UPnP network service connection should work. The future of UPnP network SaaS model will become commercially available software, commercial software can be accessed remotely via the Internet should be. Customer site activities must be managed from a central location. Application software architecture, pricing, partnerships, management should not include the character models. N should be the model. When used in small and medium enterprises have a very high value.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.17-43
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• 2021

Currently, various discussions are underway to establish a more advanced management system for public rental housing. Also, it calls for improvement methods for problems arising in management of the current rental housing system. In this regard, this study aims to evaluate determinants that affect user acceptance intention of blockchain technology to implement a new system that complements drawbacks of the current public rental housing system. The study uses the Unified Theory of Acceptance and Use of Technology (UTAUT) as a theoretical model; the study model utilizes three UTAUT variables -performance expectancy, social influence, and Facilitating conditions-, applies security, availability, and reliability that are perceived from blockchain technology as external parameters to facilitate understanding of user acceptance intention of blockchain technology, and evaluates whether innovativeness can regulate the influence of performance expectancy, social influence, and Facilitating conditions on user acceptance intention of blockchain technology. Based on the significant survey result where 274 IT technicians participated, the study applies structural equation modeling to explore structure of user acceptance intention in the blockchain-based management system for public rental housing. As a result, security-reliability and availability are found to factors as determinants for user acceptance intention, affecting implementation of the public rental housing management system, while innovativeness shows no significant statistical results related to regulation effect. This study has implications in that it understands characteristics of blockchain and empirically analyzes the relationship between the characteristics and acceptance intention to enable blockchain's contribution to activate the public rental housing management system in the future.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.83-95
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• 2021

In this study, various usage patterns were analyzed after establishing a data mart for micro mobility analysis based on the rental history of public bicycles in Seoul. Rental history data is origin-destination data that includes the rental location and time, and the return location and time. About 1500 rental locations were classified according to the characteristics of the location to create a 'station type' dimension. We also created a 'path type' dimension that displays whether the rental location and return location are the same. In addition, a derived variable called speed, which is obtained by dividing the distance used by the time used, is added, and through this, the characteristics of the riding area and the reason for the rental can be estimated. Meanwhile, administrative district link, administrative neighborhood link, and station type link were created to apply network analysis. Through this analysis, the roles and proportions of administrative districts, public facilities, and private facilities engaged in micro-mobility services were visualized. 49.9% of rentals occur at rental offices near transportation facilities, and half of them occur at rental offices near subway stations. The number of rentals during the evening rush hour is more than double that of the morning rush hour. When the path type is unidirectional, there is a fixed destination, so the distance and time used are short, and the movement speed tends to be high. In the case of round-trip, the purpose of use is exercise or leisure, so the distance and time used are long, and the movement speed is slow. It is expected that the results of the analysis can be used as reference materials for selecting new rental locations, providing convenient services for users, and developing user-specialized products.