• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.341-348
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• 2009

In this paper, we propose a grouping technique for the SDD(Synchronous Digital Duplexing) based on OFDMA(Orthogonal Frequency Division Multiple Access). The SDD has advantages of increasing data efficiency and flexibility of resource since SDD can transmit uplink signals and downlink signals simultaneously by using mutual time information and mutual channel information, obtained during mutual ranging process. However, the SDD has a disadvantage of requiring additional CS to maintain orthogonality of OFDMA symbols when the sum of mutual time difference and mutual channel length between AP(access point) and SS(subscriber station) or among SSs are larger than CP length. In order to minimize the length of CS for the case of requiring additional CS in SDD, we proposes a grouping technique which controls transmit timing and receive timing of AP and SS in a cell by classifying them into groups. Performances of the proposed grouping technique are evaluated by computer simulation.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.253-260
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• 2015

Because mass of activity records of individuals and organizations are accumulated in the digital space and amount of information is also increasing exponentially, the most urgent requirements of users is the tool for 'efficient' acquisition of 'useful' information. This paper try digital convergence to combine a domain specific technology with real time issue detection and grouping based on Web media. To derive core functionalities, we collect and analyze user requirements of national defense issue detection services. By utilizing linguistic resources specialized on national defence area and discovering features for measuring issue importance, we try to seek differentiation domain specific issue detection method. Finally we compare our detection results based on the development outputs of prototype.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1340-1346
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• 2022

In this paper, we consider a downlink non-orthogonal multiple access (NOMA) using multiple transmit antennas, where the transmit antenna selection scheme is used to reduce the system complexity. Thus, in this paper, we propose radio resource allocation and receiver selection schemes in order to improve the outage probability performance of the downlink NOMA system using the transmit antenna selection scheme. In particular, the receiver selection scheme is a method of grouping the receivers to improve the outage probability performance, and the radio resource allocation scheme is a method of allocating radio resources to each group in order to enhance the outage probability performance. In addition, through the computer simulation under the assumption of independent Rayleigh fading channels, we show that the proposed radio resource allocation and receiver selection schemes can improve the outage probability performance at the expense of the sum rate performance.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.471-482
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• 2005

The high-speed network permits Grid computing to handle large problem of management areas and share various computational resources. As there are many resources and changes of them in Grid computing, the resources should be detected effectively and matched correctly with tasks to provide high performance. In this paper, we propose a mechanism that maximizes the performance of Grid computing systems. According to a priority, grade and site of heterogeneous resources, we assign tasks to those resources. Initially, a volunteer's priority and ranking are determined by static information like as CPU speed, RAM size, storage size and network bandwidth. And then, the rank of resources is decided by considering dynamic information such as correctness, response time, and error rate. We find that overall Grid system performance is improved and high correctness using resource reallocation mechanism is achieved.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.4
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• pp.41-49
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• 2009

In ubiquitous sensor networks, sensor nodes can be compromised by an adversary since they are deployed in hostile environments. False sensing reports can be injected into the network through these compromised nodes, which may cause not only false alarms but also the depletion of limited energy resource in the network. In the security solutions for the filtering of false reports, the choice of a security threshold value which determines the security level is important. In the existing adaptive solutions, a newly determined threshold value is broadcasted to the whole nodes, so that extra energy resource may be consumed unnecessarily. In this paper, we propose an application of the recursive contract net protocol to determine the threshold value which can provide both energy efficiency and sufficient security level. To manage the network more efficiently, the network is hierarchically grouped, and the contract net protocol is applied to each group. Through the protocol, the threshold value determined by the base station using a fuzzy logic is applied only where the security attack occurs on.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.208.1-208.1
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• 2011

우리나라 전국의 사찰수는 약 22,000개로 추정되며, e-나라지표에 의하면 사찰 역사가 오래되거나 전통 양식의 건축물과 문화재 등을 간직한 사찰로 문화체육관광부가 지정하는 전통사찰은 2010년 3월말 현재 전체의 4.2%인 935개로 알려져 있다. 대도시에 위치한 사찰을 제외하면 일반적으로 사찰은 계곡에 위치하여 인근에 하천이 있으며, 유역이 작아 유량은 적으나 경사가 심해 낙차를 크게 얻을 수 있다. 또한 설계제원이 비슷한 전통사찰들을 그룹핑하고 소수력발전시스템을 Kit형태로 표준화하여 개발한다면 초기투자비를 저감할 수 있는 장점도 있다. 따라서 본 연구에서는 전통사찰에 소수력발전의 적용가능성을 타진하기 위하여 유역면적이 $49.71km^2$인 사찰 1지점을 선정하여 인근의 하천을 이용한 소수력발전 성능특성을 분석하였다. 분석결과 단위 유효낙차당 설비용량은 약 9.3kW, 연간전기생산량은 약 28,602kWh로 산정되었으며, 낙차가 커질수록 설비규모와 연간전기생산량은 비례하여 증가될 것으로 추정된다. 부존자원이 부족하여 에너지해외의존도가 97%가 넘는 현실을 감안할때 전통사찰에 대한 타당성 조사를 통해 소수력발전을 적용함으로서 사찰에서 사용되는 전기에너지의 절약과 친환경 재생에너지의 활용을 확대해 나가는 것이 바람직 할 것으로 사료된다.

• The Korean Journal of Archival Studies
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• no.58
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• pp.191-224
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• 2018

In order to effectively respond to repeated disasters, the most important thing is the systematic management of records which were produced from past disaster response processes. It is necessary to develope a business reference model(BRM) to incorporate scattered disaster safety record information resources into the record management system. In this regard, this study examined crisis management standard operation procedures(SOP) manuals and analyzed common businesses of disaster and safety response processes. Based on analysis of 28 manuals three times, 1,667 main business transactions are drawn, which are grouped by 5 middle functions and 20 small functions. Furthermore, by looking at forecast records by business type, several insight is proposed in terms of disaster and safety response business processes and of disaster and safety records management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.942-955
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• 2000

This paper proposes enhanced designs of global service logic and information flow for the mass-call based IN service, which increase call completion rates and optimize the resource in joint wired and wireless networks. In order to hanve this logic implemented, we design a Dynamic Queue Manager(DQM) applied to the call queuing service feature in the Service Control Point(SCP). In order to apply this logic to wireless service subscribers as well as wired service subscribers, the service registration flags between the Home Location Register(HLR) and the SCP are managed to notify the DQM of the corresponding service subscribers’ mobility. Hence, we present a dynamic queue management mechanism, which dynamically manages the service group and the queue size based on M/M/c/K queueing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the DQM, we simulator and analyze the relationship between the number of the subscriber’s terminals and the drop rate by considering the service increment rate. The appropriate waiting time in the queue as required is simulated according to the above relationship. Moreover, we design and implement the DQM that includes internal service logic interacting with SIBs(Service Independent building Blocks) and its data structure.