• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.533-542
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• 2001

In this paper, we present a scheduling method for real-time mobile transaction manager in mobile computing environment. The proposed method checks whether a transaction is executable or not. It is able to by considering not only the deadline of real-time data in mobile hosts. And then, it schedules the real-time mobile transactions by making optimal execution window based on the priority queue, while considering transaction value and deadline. Disconnection with mobile hosts is monitored in selecting the transaction for execution. Using the proposed method reduces the number of restarting times after transaction aborts which is caused by the violation of the validity constraints of real-time data. And in has merits of maximizing the sum of values of real-time mobile transactions which meet the deadline. The performance evaluation demonstrates that the number of committed real-time transactions within the deadline is improved by 20%. This method can be used in real-time mobile transaction manager is such environments as cellular communications, emergency medicine information system and so on.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.534-542
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• 1999

A sell-designed rate control strategy can improve overall picture quality for video transmission over a constant bit rate channel and the rate control method is not a normative part of MPEG-video standard, the performance of MPEG video codec can be quite different depends on how to implement the rate control scheme. The rate control scheme proposed in MPEG show good results when scene changes is not occurred. But it has weakness that it does not properly handle scene-changed pictures. Therefore picture quality after scene change is deteriorated, and possibility of overflow occurrence becomes high. In this paper, a new method for detection of scene change occurrence using local variance and a new determination scheme for adaptive quantization parameter, mqunt, which can consider local characteristic of an image by using previously computed the local variance from the scene change detection part are proposed. IN addition, and adaptive rate control scheme which can handles scene changed picture very efficiently by scene-changed picture is proposed. Computer simulations are performed to verify the performance of the proposed algorithm. The suggested detection algorithm precisely detected scene change. And the proposed rate control scheme shows better rate control performance as compared with that of the conventional MPEG scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.323-335
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• 2015

Mobile healthcare is a fusion of information technology and biotechnology and is a new type of health management service to keep people's health at anytime and anywhere without regard to time and space. The WBAN(Wireless Body Area Network) technology that collects bio signals and the data analysis and monitoring technology using mobile devices are essential for serving mobile healthcare. WBAN consisting of users with mobile devices meet another WBAN during movement, WBANs transmit data to the other media. Because of WBAN conflict, several nodes transmit data in same time slot so a collision will occur, resulting in the data transmission being failed and need more energy for re-transmission. In this thesis, we proposed a MAC protocol for WBAN with mobility to solve these problems. First, we proposed a superframe structure for WBAN. The proposed superframe consists of a TDMA(Time Division Muliple Access) based contention access phase with which a node can transmit data in its own time slot and a contention phase using CSMA/CA algorithm. Second, we proposed a network merging algorithm for conflicting WBAN based on the proposed MAC protocol. When a WBAN with mobility conflicts with other WBAN, data frame collision is reduced through network reestablishment. Simulations are performed using a Castalia based on the OMNeT++ network simulation framework to estimate the performance of the proposed superframe and algorithms. We estimated the performance of WBAN based on the proposed MAC protocol by comparing the performance of the WBAN based on IEEE 802.15.6. Performance evaluation results show that the packet transmission success rate and energy efficiency are improved by reducing the probability of collision using the proposed MAC protocol.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.372-385
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• 2002

In this paper, we propose an efficient buffer replacement method for the real-time multimedia data. The proposed method has multi level priority to consider the real-time characteristics. Each priority level is divided into a cold data set that is likely to be referenced for the first time and a hot data set that is likely to be re-referenced. An operation to select the victim data is sequentially executed from the cold set with the minimum priority level to the hot set with the maximum Priority level. It is chosen only at the lower level than or equal to the priority of the transaction that requests a buffer allocation. In the cold set, our method selects a media that has the maximum size in the level for a target of victim first of all. And in the hot set, our method selects a medium that has the maximum interval of the reference first of all. Since it maintains many popular media in the limited buffer space, the buffer hit ratio is increased. It also manages many service requests. As a result, our method improves the overall performance of the system. We compare the proposed method with the Priority-Hints method in terms of the buffer hit ratio and the deadline missing ratio of transactions. It is shown through the performance evaluation that our method outperforms the existing methods.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.3
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• pp.271-292
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• 2019

Recently, the central administrative agency changed its business management system to cloud-based On-nara 2.0. To transfer and manage the records of the cloud business management system, the National Archives Service has developed and distributed a cloud-based records management system. It serves as an opportunity to maximize the benefits of cloud computing and redesign the records management to be more effective and efficient. The process and method of electronic record management can be transformed through digital technologies. First, we can change the transfer method for electronic records. When the business and the records management systems share the same cloud storage, it is possible to transfer the content files between the two systems without moving the contents files physically, thus copying only the metadata and reducing the cost and the risk of integrity damage. Second, the strategy for allocating storage space for contents can be conceived. Assuming that the cloud storage is shared by the business and the record management systems, it is advantageous to distinguish the storage location based on the retention period of the content files. Third, systems that access content files, such as records creation, records management, and information disclosure systems, can share the cloud storage and minimize the duplication of content files.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.212-215
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• 2019

지난 4월4일 고성 산불로 사망자 2명과 부상자 1명, 가옥 500여 채, 삼림 1757ha가 불에 탔다. 강원 산불에 이어 영덕지진 등에서 늑장대응을 보여준 재난방송시스템에는 많은 국민들에게 실망감을 안겨주었다. 재난방송 주관방송사인 KBS는 물론, MBC, SBS의 경우도 재난방송시스템에 관련 된 측면에서 본다면 아직 이웃나라 인 일본에 비해서는 매우 열악한 형편이다. 그럼에도 불구하고 점점 대형화, 다발화 하는 재난발생에 대응하기 위해서는 국가적인 차원에서도 특단의 조치가 필요하다. 미국의 경우는 차세대 재난정보 전달체계인 IPAWS(Integrated Public Alert and Warning System)를 개발해 지상파뿐만 아니라, 케이블TV, SNS 등 다양한 매체를 통해 재난정보를 신속하게 전달하고 있다. 일본도 이와 유사한 재난경보전달시스템인 J-Alert를 개발해 2020년까지는 '재난 약자 제로(Zero)시대'를 목표로 구현하고 있다. 우리나라는 지난 아현동 KT 화재사건에서도 경험했듯이 통신이 먹통이 되는 통신블랙아웃도 경험했다. 따라서 대형재난발생 시는 신속한 재난경보전달시스템이 재난피해를 줄일 수 있는 가장 중요한 생명줄이 될 수 있다. 미국이나 일본의 경우는 재난방송전달시스템을 관련법령으로 제도화 하고 있다. 특히, 일본에는 재난에 관한 모법이라고 할 수 있는 (1)"재해대책기본법"이 있는데, 이는 재해로부터 국토, 국민의 생명과 재산을 보호하기 위한 기본법으로 규정되어 있다. 그 밖에도 (2)방송법 (3)대규모지진대책특별 조치법 (4)국민보호법 (5)소방조직법 (6)수해방지법 등으로 규정하고 있다. 과거 일본도 우리나라와 같이 대형 산불이 잦았으나 요즘은 소형 산불만 발생하는 추세다. 이는 NHK가 보유한 700여 대의 로봇카메라와 전 국토를 샅샅이 감시하는 CCTV 덕택이다. 또한, NHK 보도국의 '기상 재해센터'는 재난에 대비해 40여 명의 전문 인력이 24시간 대응체제를 갖추고 있다. 나아가 NHK는 전국 12개의 거점지역에 헬리콥터 15대를 배치하여 신속하게 취재하고 있다. 이 뿐만 아니라, 46개의 지역방송국을 7개의 거점방송국으로 분할하여, 거점방송국마다 40여명의 카메라맨을 상주시켜 언제든지 재난을 취재할 수 있도록 하고 있다. 세계 각국에서 사용하고 있는 방송 주파수는 공공재(公共材)다. 국제전기통신연합(ITU : International Telecommunication Union)으로부터 주파수를 할당받아 사용하고 있기 때문에 주파수에 관한 사용 권한은 각국의 국민 모두에게 있다. 그러나 효과적인 주파수 활용을 전제로 정부가 일정한 자격을 갖춘 방송사업자에게 일시적으로 주파수 사용권을 위임하고 있다. 따라서 일본 정부도 국가적인 위기나 대형 재난발생으로 국민들의 생명과 재산이 위협받고 있을 때에는 공공재인 주파수를 즉시 재난방송으로 사용할 수 있도록 <재해대책기본법 제6조>와 방송법 제108조에 규정하고 있다.

• 한국노년학
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• v.39 no.2
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• pp.213-229
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• 2019

The purpose of this study was to examine various factors influencing the needs of Seoul's newly implemented outreach community services for older adults, and to suggest the direction of the outreach community health services in Seoul. A multi-level regression was conducted using data collected by face-to-face interviews from 1,000 individuals aged 65 and 70 in 17 districts, where participated in the Seoul's outreach community services. The results demonstrated that socioeconomic status (higher income and living alone), health status (having multiple chronic conditions and depression, lower health literacy), limited experience of the outreach community services, and low government trust at the individual level were associated with higher unmet need for the community outreach services. In addition, shorter participation period of the outreach services and financial independency at the district level were associated with higher unmet need for the services. The findings from this study implies the need for improving the quality of services by focusing on vulnerable groups such as individuals with lower income and worse health status. In addition, the outreach community health services may need to target individuals aged 66 to increasing efficiency of the services through utilizing results of life-cycle health checkup by the National Health Insurance Corporation.

• International Area Studies Review
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• v.15 no.1
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• pp.469-493
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• 2011

This paper attempts to examine the economic impact of technological barrier to trade(TBT) between Korea and China by using international input-output approach. With the tariff/quota reduced or eliminated since WTO's launch, the interest in TBT as a non-tariff barrier has been increased, and then there have so far been a large number of empirical studies on quantifying its effect in foreign. But still this area of study in Korea is limited in the literature survey. In encouraged in this situation, focusing on bilateral trade between Korea and China, which has been significantly increased in recent years, we have tried to estimates the impact of TBT on their output and employment. We use Asian International Input-Output Table(AIIO) for the year 2000 published by IDE-JETRO, and also use the estimated sectoral TBT provided by Ha et al.(2010). According to the result, there will be generated $3.63 billions values in outputs, and 18.1 millions persons in employments at most. And also we found that there is weak interdependence in sectoral and spatial linkage between two countries.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.118-131
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• 2019

In order to provide 8K UHD contents of terrestrial broadcasting with a large capacity, the terrestrial broadcasting system has various problems such as limited bandwidth and so on. To solve these problems, UHD contents transmission technology has been actively studied, and an 8K UHD broadcasting system using terrestrial broadcasting network and communication network has been proposed. The proposed technique is to solve the limited bandwidth problem of terrestrial broadcasting network by segmenting 8K UHD contents and transmitting them to heterogeneous networks through hierarchical separation. Through the terrestrial broadcasting network, the base layer corresponding to FHD and the additional enhancement layer data for 4K UHD are transmitted, and the additional enhancement layer data corresponding to 8K UHD is transmitted through the communication network. When 8K UHD contents are provided in such a way, user can receive up to 4K UHD broadcasting by terrestrial channels, and also can receive up to 8K UHD additional communication networks. However, in order to transmit the 4K UHD contents within the allocated bit rate of the domestic terrestrial UHD broadcasting, the compression rate is increased, so a certain level of image deterioration occurs inevitably. Due to the nature of UHD contents, video quality should be considered as a top priority over other factors, so that video quality should be guaranteed even within a limited bit rate. This requires packet scheduling of content generators in the broadcasting system. Since the multiplexer sends out the packets received from the content generator in order, it is very important to make the transmission time and the transmission rate of the process from the content generator to the multiplexer constant and accurate. Therefore, we propose a variable transmission scheduler between the content generator and the multiplexer to guarantee the image quality of a certain level of UHD contents in this paper.