• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.43-53
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• 2008

Hyper text transfer protocol (HTTP) over transmission control protocol (TCP) is currently used to transfer objects in the Internet. Stream control transmission protocol (SCTP), an alternative to TCP, which allows for independent delivery among streams, and can thus reduce the mean response delay of web object. We present an analytical model to find the mean response delay for HTTP over SCTP, therefore, estimate the effectiveness of SCTP over TCP. Typical TCP delay models assume the wired environment. On the contrary, the proposed model in this paper assumes the multiple packet losses and wireless environment where fast retransmission is not possible due to small window. The estimated mean response time can be used the benchmark to meet quality of service (QoS) at end-user. We validate the accuracy of our model using experiments. It is shown that the differences between the results from model and those from experimental are very small below 6 % on average. We also find that the mean response delay for HTTP over SCTP is less than that for HTTP over TCP.

• Korean Management Science Review
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• v.27 no.3
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• pp.161-196
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• 2010

This paper empirically investigates the impact of winning a service quality award on the market value in Korea. We estimates the mean "abnormal" change in the stock prices of sample firms when information of winning a service quality award was publicly announced. To access the validity of the research question, this paper employed collected 47 firms data that received the Korean Service Quality Awards so far. Event study methodology was used to analyze the effect of Korean service quality awards. The findings are as follows; The average abnormal returns on the event date are not significant at the 0.05 level which means that the receiving Korean Service Quality Awards has no influence on the firms' market value. On the other hand successive awarded firms have an increasing effect on the market value and it is significant at the 0.05 level. Furthermore, the results show that the factors of firm size such as firm's total assets are critical to vary the firms' abnormal returns. There might be some limitations in this study. The most obvious problem is the limitation of sample size. Although 518 sample cases were found during the period from 2000 to 2008, most of the cases were deleted according to the sample criteria. We are expecting the future research with more data and more precise results. Furthermore, our research consider the only two service award institutions even though there are several different service award authorities in Korea. It is needed to expand the research scope and range to adopt the various service award institutions for the future work.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.318-329
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• 2013

Spatial information has influenced government policy formation, business strategy implementation, and our everyday life enormously. Digital earth enterprises providing global spatial data services emerge as spatial data industry grows rapidly. So it is highly desirable to grasp recent trends in the industry and find critical success factors (CSFs) for the digital earth firms. The purpose of this study is to compare strategies of digital earth enterprises and find CSFs for them. In addition, strategy analysis framework elaborations, systematic analysis of spatial data industry and market segmentation based on value chain are also performed to trace and cope with the volatile industry environment. Derived CSFs are as follows. First, acquisition of differentiated high quality spatial data is needed. Second, customer oriented convergent contents should be developed. Third, advanced platform functionalities must be provided to consumers. Finally, construction of efficient and effective global value chain is desirable.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.401-411
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• 2009

Commercial sports facilities dissatisfy and have the problem in facility management and social institution when we compare with advanced nation. To develop commercial sports facilities, government must improve facility management ability and increase social institutional support. First, to improve facility management ability, government must make effort for instructor's treatment better, employment extension, strengthening of management and marketing ability, improvement of service quality and consumer satisfaction, facility's modernization. Second, to extend social institutional support, government have to make effort for cultivation and disposition of specialized human power, deregulation and institution improvement of sports facility, support extension of taxes and finance, establishing information network of sports facility. Finally, the main body of commercial sports facilities have to make progressive effort for improving facility management ability, and government have to make excellent social environment developing commercial sports facilities.

• Proceedings of the Korean DIstribution Association Conference
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• 2007.08a
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• pp.27-38
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• 2007

본 연구는 갈수록 설 자리를 잃어 가는 지역 상권에 있어서 최근 10년 여 기간 동안 원주시에서 지속적으로 정치${\cdot}$경제적, 사회적 이슈로 제기되어 왔던 문제는 지하상가 상권의 침체와 활성화 문제라 할 수 있다. 원주 지하상가는 정부의 요구에 의하여 민방공 대피시설로 생겼으며, 각종 연구보고서나 학술세미나의 정책주제로 지하상가 도심 활성화 문제가 거론되고 있다. 특히 매번 지방선거에서는 지하상가 상권 활성화를 선거공약으로 제시하지 않은 후보가 없었을 정도였다는 것을 우리는 기억하고 있다. 그만큼 지하상가의 문제가 심각하다는 의미이며, 지하상가의 활성화를 통한 도시개발은 원주시민 공동의 과제라는 점을 이해 할 수 있다. 이와 같은 지역사회의 요청에 따라 그동안 수많은 개선안들이 원주시 차원에서 추진되었다. 지하상가 주변에 특화거리를 지정${\cdot}$조성하는 '특화거리 조성사업'에서부터, 주차문제 해결을 위한 '공영주차장 건설사업', '재래시장 현대화사업', '주거환경개선사업', '하상도로 건설사업', '지하상가 리모델링사업' 등 단기 및 중장기 사업계획이 추진되고 있다. 그럼에도 불구하고 크게 개선되지 못하고 있는 실정이며, 앞으로 계속 우리가 깊은 관심을 갖고 해결해 나가야 할 과제로 남아 있다. 그러나 최근 원일프라자 준공을 전후하여 지하상가는 조금씩 변화의 조짐을 보이고 있으며, 일부에서는 도심이 활성화될 것이라는 성급한 판단을 내리기도 한다. 원주시는 미약하나마 인구가 증가하는 추세이며, 전반적으로 도심이 침체의 늪에서 벗어나고 있는 인상을 주고 있기 때문이다. 그러나 이러한 변화가 과연 도심이 활성화되고 있는 징후로 볼 것인가? 특히 이러한 변화의 조짐이 원일프라자의 준공과 직접적인 관련성을 갖고 있는가? 몇가지 변화의 사례를 가지고 간단하게 판단할 수는 없다. 그러나 원일프라자의 준공은 도심지역의 개발${\cdot}$정비를 예정하고 있으며, 장기적으로는 도심 활성화의 중요한 동인이 될 수 있음을 부인할 수 없다. 따라서 본 발제에서는 이와 같은 상황적 변화를 전제로 하여 지하상가 리모델링을 통한 도심활성화와 선진사례를 받아들임으로 지역상권 활성화 방향으로 전환하는 것이 바람직할 것으로 판단된다.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.73-81
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• 2016

The electronic commerce environment allows customers to search for information and purchase products and services via direct contact with internet markets. Purchasing through the internet is not a real experience of purchasing, but is based on some pictures, information and advertisements of products. To improve E-commerce environment in Iran, purchasing behavior of Iranian young adults in the internet shopping mall is analyzed in this study. The factors which influence the motivation of internet shopping and the selection of internet shopping mall is investigated, and statistical tests were applied between these factors and other variables such as gender, job, age and education. The results of the tests showed that there is a gender difference on one of the shopping mall selection factor (i.e., abundant information about products); also there is a gender difference on the one of the shopping motivation factor (i.e., possibility of comparing products). Besides, there is a job difference (student or non-student) on the factor of 'Purchase frequency per month'. Other facts are also found that Iranian consumers are not sure about a product's quality, so they refuse to buy products such as foods, clothes and other products. Additionally, they are dissatisfied about the safety of internet shopping malls.

• KIISE Transactions on Computing Practices
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• v.23 no.3
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• pp.171-176
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• 2017

Recently, several information-technology research projects such as those for high-performance computing, the cloud service, and the DevOps methodology have been advanced to develop the efficiency of satellite data-processing systems. In March 2019, the Geostationary Ocean Color Imager II (GOCI-II) will be launched for its predictive capability regarding marine disasters and the management of the fishery environment; moreover, the GOCI-II Ground Segment (G2GS) system for data acquisition/processing/storing/distribution is being designed at the Korea Ocean Satellite Center (KOSC). The G2GS is composed of the following six functional subsystems: data-acquisition subsystem (DAS), data-correction subsystem (DCS), precision-correction subsystem (PCS), ocean data-processing subsystem (ODPS), data-management subsystem (DMS), and operation and quality management subsystem (OQMS). The G2GS will enable the real-time support of the GOCI-II ocean-color data for government-related organizations and public users.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.310-315
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• 2017

In a centralized control structure, the software defined network controller manages all openflow enabled switched in a data plane and controls the telecommunication between all hosts. In addition, the network manager can easily deploy the network function to the application layer with a software defined network controller. For this reason, many methods for network management using a software defined network concept have been proposed. The main policies for network management are related to traffic Quality of Service and resource management. In order to provide Quality of Service and load distribution for network users, we propose an efficient routing method using a naive bayesian algorithm and transmission delay estimation module. In this method, the forwarding path is decided by flow class and estimated transmission delay result in the software defined network controller. With this method, the load on the network node can be distributed to improve overall network performance. The network user also gets better dynamic Quality of Service.

• Journal of KIISE
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• v.44 no.8
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• pp.767-773
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• 2017

In a distributed system environment, such as a cloud database, the tail latency needs to be kept short to ensure uniform quality of service. In this paper, through experiments on a Cassandra database, we show that long tail latency is caused by a lack of memory space because the database cannot receive any request until free space is reclaimed by writing the buffered data to the storage device. We observed that, since the performance of the storage device determines the amount of time required for writing the buffered data, the performance degradation of Solid State Drive (SSD) due to garbage collection results in a longer tail latency. We propose a garbage collection synchronization technique, called SyncGC, that simultaneously performs garbage collection in the java virtual machine and in the garbage collection in SSD concurrently, thus hiding garbage collection overheads in the SSD. Our evaluations on real SSDs show that SyncGC reduces the tail latency of $99.9^{th}$ and, $99.9^{th}-percentile$ by 31% and 36%, respectively.

• Journal of Advanced Navigation Technology
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• v.6 no.3
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• pp.188-194
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• 2002

DBS is utilized as very useful media in information-oriented society because it covers wide service area and provide high quality services. But DBS needs skill that can receive DBS signal at move. In this paper, it is considered a development of a device to receive DBS and design of a low noise downconverter that use tracking antenna to receive DBS at mobiles unit and ships which navigate in Korea peninsula coast. The structure of dual phase LNB is composed of LNA, BPF, oscillator, mixer, and IF amplifier. And for the position tracking, two input-output phase performed in phase. Measured results showed good performance that with respect to input signal 11.7 GHz~12.2 GHz, noise figure is 0.87 dBmax and conversion gain 62 dB, temperature characterization ${\pm}400$ kHz in respect to - 30 to $60^{\circ}C$, and phase noise -101 dBc/Hz in respect to offset 100 kHz.