• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.429-438
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• 2001

GPS (Global Positioning System) is the most ideal navigation system which can be used on the earth irrespective of time and weather conditions. GPS has been used for various applications such as construction, survey, environment, communication, intelligent vehicles and airplanes and the needs of GPS are increasing in these days. This paper deals with the design and implementation of the RTOS (Real-Time Operating System) for a GPS navigation computer in the GPS/INS integrated navigation system. The RTOS provides the optimal environment for execution and the base platform to develop GPS application programs. The key facilities supplied by the RTOS developed in this paper are priority-based preemptive scheduling policy, dynamic memory management, intelligent interrupt handling, timers and IPC, etc. We also verify the correct operations of all application tasks of the GPS navigation computer on the RTOS and evaluate the performance by measuring the overhead of using the RTOS services.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.287-292
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• 2001

Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.

• Journal of Korean Society of Rural Planning
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• v.26 no.2
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• pp.39-49
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• 2020

This study was attempted to grasp the push-pull factors of urban to rural migrants in relation to services and infrastructure of rural welfare and culture. Online and offline survey were conducted for urban residents who were willing to return to the rural area and those who were already returning to the rural area. In the fields of health care, social welfare, and education, it was found that the satisfaction level of urban-to-rural migrants was relatively higher than those of latent urban-to-rural migrants. In the field of culture, leisure and sports, the level of satisfaction and concern were similar, so it was found that the expectations for the field were relatively high before returning rural area. As for the agreement degree to expand support, the demand for emergency medical facilities and dementia care program was the highest, and the demand for health care was found to be relatively high. The results of the survey on the top priority items indicate that latent urban-to-rural migrants require support of facility and space item and expansion of program item, and urban-to-rural migrants have high demand for expansion of program item in all field except healthcare field. The results of this study are expected to provide useful information for establishing the direction of the rural area development project in connection with the revitalization of policy of people return to rural area.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.287-293
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• 2021

Recently, public certificates issued by nationally-recognized certification bodies have been abolished, and internet companies have issued their own common certificates as certification authority. The Electronic Signature Act was amended in a way to assign responsibility to Internet companies. As the use of a joint certificate issued by Internet companies as a certification authority is allowed, it is expected that the fraud damage caused by the theft of public key certificates will increase. We propose an authentication model that can be used in a security gateway that combines PKI with a blockchain with integrity and security. and to evaluate its practicality, we evaluated the security of the authentication model using Sugeno's hierarchical fuzzy integral, an evaluation method that excludes human subjectivity and importance degree using Delphi method by expert group. The blockchain-based joint certificate is expected to be used as a base technology for services that prevent reckless issuance and misuse of public certificates, and secure security and convenience.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.11-17
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• 2021

Software-defined networking provides a programmable and flexible way to manage the network by separating the control plane from data plane. However, the limited switch memory restricts the number of flow entries in the flow table used to forward packets. This leads to flow table overflow and flow entry reinstallation, which severely degrade the network performance. Therefore, this paper proposes a comprehensive policy for timely eviction of inactive flow entries to optimally maintain flow tables usage. In particular, statistics of user datagram protocol flow entries are periodically sampled to enable the inactive entries to be evicted early. Through traffic-based experiments, we found that the proposed system reduces the number of overflow occurrences and flow entries reinstallation compared to the random and FIFO policies.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.5
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• pp.399-407
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• 2018

Objective: Regionalization is one of the principal subjects for the advancement of rural emergency medical service systems in South Korea. This study shows the characteristics of interhospital transfer and status of the incidence of three major emergency disorders (acute myocardial infarction [AMI], acute stroke, and severe trauma) in one local province. Methods: A retrospective study was conducted for patients with three major emergency disorders who visited emergency medical facilities in one local province from January 2013 to December 2015, on the basis of the National Emergency Department Information System (NEDIS) data. Results: The incidence of three major emergency disorders had increased annually. Patients with each of these disorders tended to choose distinguishing methods of visiting emergency medical facilities. AMI patients tended to visited emergency medical facilities using private cars or on foot, while severe trauma patients usually visited by 119 ambulance, and acute stroke patients used 119 ambulance and private car in similar amounts. Overall, 65% of AMI patients were treated in intraregional medical facilities, but about 70% of acute stoke and severe trauma patients were transferred outside of the region. Conclusion: Because each of these disorders has an individual characteristic, it is difficult to expect a solution for the problems associated with emergency disorders just by assuring the availability of medical resources. Based on regionalization, a policy to provide the optimal treatment for those emergency disorders should be developed by planning public medical service systems based on the individual characteristics of emergency disorders, the standardized transfer plans of emergency patients and the assurance for mobilization and sharing of confined medical resources.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.299-314
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• 2016

The aim of this paper is to review integrated assessment studies conducted to address the impacts of climate change sea-level rise on agricultural sector and to derive suggestions for improving the integrated assessment process to assist decision-makers in establishing climate change adaptation policy. We collect integrated assessment studies which are based on the impact-pathway analysis, compare their step-by-step procedures and identify main factors addressed in each step. The assessment process is typically carried out in the sequence of scenario development, determination of assessment scope, physical impact assessment, economic analysis and synthesis of the outcomes from each step. We identify two types of integrated assessment. The first one examines the impacts of changes in temperature and/or precipitation on the crop-cultivation patterns and/or agricultural productivity and resulting economic effects on agricultural sector. The other investigates the impacts of sea-level rise on land use/coverage and resulting economic damages in terms of land-value loss where the effects on agriculture is treated as one sector among others. To enhance integrated assessment, we suggest that 1) scenarios need to incorporate the effects of climate change and sea-level rise simultaneously, 2) scope of the assessment needs to be extended to include ecosystem services as well as crop production, 3) social and cultural aspects need to be considered in addition to economic analysis, and 4) synthesis of the outcomes from each step should be able to combine quantitative as well as qualitative information.

• The Journal of Society for e-Business Studies
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• v.23 no.4
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• pp.41-62
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• 2018

Despite the rapid growth of the mobile shopping market, major market participants are continuing to suffer operating losses due to severe competition. To solve this problem, the mobile shopping market requires research to improve customer satisfaction and customer loyalty rather than excessive competition. However, the existing studies have limits to reflect the direct needs of customers because they extract the factors on the basis of the Technology Acceptance Model and the literature study. In this study, to reflect the direct requirements of users of mobile shopping Apps, we derived concretely and various factors influencing customer satisfaction through a topic analysis using user reviews. And then we assessed the importance of derived factors to customer satisfaction and analyzed the effects of customer satisfaction on customer complaints and customer loyalty on a structural equation model based on the American customer satisfaction index. We expect that our framework linking a topic analysis and a structural equation model is to be applicable to studies on the customer satisfaction of other mobile services.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.57-68
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• 2019

Rural tourism has been identified as providing opportunities to revitalize the rural economies since early 2000s. During last decade in South Korea, government has enacted many policies aiming to establish tourism support programs as well as instigating activities between rural and nearby urban districts. In particular, the promotion of the rural tourism has been actively sought in various forms of products and services, such as green tourism village, village festival, one-company one-village campaign and etc. However, in order to prepare effective policies, it is very crucial to identify measureable evaluation criteria that can be used to assess socio-economic situations of the rural districts. Such criteria should be objective, timely and provide insights about living conditions of local residents and relevant properties. They can also be used to evaluate if progress is being made after the policies are implemented. While considerable efforts and resources have been invested to aid the tourism programs in South Korea, we still lack such systematic means to quantify and evaluate its impact on rural districts. In this work, we have applied regional deprivation analysis on well-established community experiential and recreational business in rural villages throughout the country based on three criteria (i.e., population, local commerce, and buildings). Surprisingly, the result shows that the implementation of the community experiential and recreational businesses did not bring any noticeable changes to at least one of the evaluation criteria. We concluded that the current government policies on revitalization of rural tourism at the village scale is insufficient for bringing meaningful socio-economic impacts to rural districts, with rare exceptions.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.179-187
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• 2019

Developing countries, including Africa, are experiencing very little human resources development due to the deprivation of equal educational opportunities, poor educational conditions, and the gap in information technology with developed countries. Developing countries that do not have excellent human resources are lagging behind in globalization competition with developed countries, and the problem of 'human resource development' in developing countries can not be avoided. In developing countries, education budgets are too low to meet education needs and compulsory education, and therefore they are not adequately responding to the increasing demand for education. The lack of education budget is due to the lack of education infrastructure. In this study, the NAS based server is configured to configure functions such as educational content and learning management, and the client area is presented with solutions for various media such as tablet, PC, and beam projector. And to support optimized e-learning services in developing countries by constructing a SCORM-based platform.