• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.60-63
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• 2012

최근 스마트폰 시장에서 제품 수명주기가 계속 짧아지고 있다. 소비자는 항상 최신의 스마트폰을 원하고 있고, 그로 인해 스마트폰 교체시기가 점점 짧아지는 추세이다. 그러나 스마트폰의 교체시 저장되어 있는 개인적인 자료의 백업 및 복원은 필수적이다. 본 논문에서는 소프트웨어적 지식이 없는 소비자들이 안드로이드 시스템에서 터치 몇 번으로 쉽고 간편하게 주소록이나 SMS 메시지 등의 자료를 저장하고 백업할 수 있는 시스템의 개발에 대해서 설명한다. 본 시스템을 이용하면 일반 소비자들이 필요한 자료를 저장하고 백업을 할 수 있어 시간을 절약하고 불필요한 노력을 줄일 수 있을 것으로 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.50-53
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• 2010

최근 DSMS의 연구가 활발히 진행되고 있고, 그에 따른 고가용성 서비스를 제공하기 위한 환경으로 확장되고 있다. DSMS와 같은 실시간 데이터베이스 응용 시스템 분야나 임무 결정적인 응용 시스템을 다루는 산업 분야에서 가용성을 유지 하지 못하는 것은 치명적인 결과를 초래 할 수 있다. 이런 DSMS환경에서 고가용성을 유지하는 기법으로는 Active/Active 알고리즘과 Active/Standby기법이 있다. 하지만 이 기법들의 고가용성을 유지하기 위해 주 서버와 동일한 규모의 보조 서버를 유지해야 하는 단점이 있다. 본 논문에서는 질의를 두 가지 타입으로 나누어 누적 데이터가 필요한 질의들만 실시간 동기화를 통해 보조 서버에 유지하고 나머지 질의들에 대해서는 메타 데이터들만 보조 서버에 유지해 보조 서버의 규모를 줄일 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.459-460
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• 2009

과거 네트워크는 물리적 회선을 이용한 유선 네트워크 기반의 연구를 통하여 각 노드간의 통신을 수행하였다. 하지만 시대가 흐름에 따라 통신환경이 유선 네트워크에서 무선 네트워크 기반의 통신으로 이동하였으며 그에 관한 연구가 활발히 진행되고 있다. 특히 clustering routing 기법은 무선 네트워크 환경에서의 한계였던 에너지 소모 문제를 보완하는 기법으로서 각광받고 있다. LS2RP는 이동성이 심한 Ad Hoc 네트워크 환경에서 CH가 backup을 통해 해당 cluster를 벗어날 경우를 대비한다. 하지만 CH가 cluster를 벗어난 이후 data chunk 결합을 통한 ID database 복구와 CH 재선정을 수행하기 때문에 그동안 network의 사용이 불가능해진다는 문제점을 가지고 있다. 따라서 본 논문에서는 CH의 이동을 예측하여 미리 sub CH를 선정하여 네트워크의 안정성을 강화하는 기법을 제시한다. 시뮬레이션 수행 결과 이동성에 따른 control traffic 측면에서 기존의 LS2RP에 비해 12% 더 높은 performance를 보이고 있음을 알 수 있었다.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.142-148
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• 2015

Purpose: To develop new on-line statistical program for the Korean Society for Radiation Oncology (KOSRO) to collect and extract medical data in radiation oncology more efficiently. Materials and Methods: The statistical program is a web-based program. The directory was placed in a sub-folder of the homepage of KOSRO and its web address is http://www.kosro.or.kr/asda. The operating systems server is Linux and the webserver is the Apache HTTP server. For database (DB) server, MySQL is adopted and dedicated scripting language is the PHP. Each ID and password are controlled independently and all screen pages for data input or analysis are made to be friendly to users. Scroll-down menu is actively used for the convenience of user and the consistence of data analysis. Results: Year of data is one of top categories and main topics include human resource, equipment, clinical statistics, specialized treatment and research achievement. Each topic or category has several subcategorized topics. Real-time on-line report of analysis is produced immediately after entering each data and the administrator is able to monitor status of data input of each hospital. Backup of data as spread sheets can be accessed by the administrator and be used for academic works by any members of the KOSRO. Conclusion: The new on-line statistical program was developed to collect data from nationwide departments of radiation oncology. Intuitive screen and consistent input structure are expected to promote entering data of member hospitals and annual statistics should be a cornerstone of advance in radiation oncology.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.75-80
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• 2013

This article presents the design of long range navigation (LORAN)-disciplined oscillator (LDO), employing the timing information of the LORAN system, which was developed as a backup system that corrects the vulnerability of the global positioning system (GPS)-based timing information utilization. The LDO designed on the basis of hardware generates a timing source synchronized with reference to the timing information of the LORAN-C receiver. As for the LDO-based timing information measurement, the Kalman filter was applied to estimate the measurement of which variance was minimized so that the stability performance could be improved. The oven-controlled crystal oscillator (OCXO) was employed as the local oscillator of the LDO. The controller was operated by digital proportional-integral-derivative (PID) controlling method. The LDO performance evaluation environment that takes into account the additional secondary factor (ASF) of the LORAN signals allows for the relative ASF observation and data collection using the coordinated universal time (UTC). The collected observation data are used to analyze the effect of ASF on propagation delay. The LDO stability performance was presented by the results of the LDO frequency measurements from which the ASF was excluded.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.371-388
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• 2014

Cognitive Radio (CR) has been recently proposed as a promising technology to remedy the problems of spectrum scarcity and spectrum underutilization by enabling unlicensed users to opportunistically utilize temporally unused licensed spectrums in a cautious manner. In Cognitive Radio Ad Hoc Networks (CRAHNs), data routing is one of the most challenging tasks since the channel availability and node mobility are unpredictable. Moreover, the network performance is severely degraded due to large numbers of path failures. In this paper, we propose the Fault-Tolerant Cognitive Ad-hoc Routing Protocol (FTCARP) to provide fast and efficient route recovery in presence of path failures during data delivery in CRAHNs. The protocol exploits the joint path and spectrum diversity to offer reliable communication and efficient spectrum usage over the networks. In the proposed protocol, a backup path is utilized in case a failure occurs over a primary transmission route. Different cause of a path failure will be handled by different route recovery mechanism. The protocol performance is compared with that of the Dual Diversity Cognitive Ad-hoc Routing Protocol (D2CARP). The simulation results obviously prove that FTCARP outperforms D2CARP in terms of throughput, packet loss, end-to-end delay and jitter in the high path-failure rate CRAHNs.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2061-2065
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• 2009

Two simple algorithm modifications are made to the THRASH data retrieval program with the aim of improving analysis speed for complex Fourier transform ion cyclotron resonance (FTICR) mass spectra. Instead of calculating the least-squares fit for every charge state in the backup charge state determination algorithm, only some charge states are pre-selected based on the plausibility values obtained from the FT/Patterson analysis. Second, a modification is made to skip figure-of-merit (FOM) calculations in the central m/z region between two neighboring peaks in isotopic cluster distributions, in which signal intensities are negligible. These combined modifications result in a significant improvement in the analysis speed, which reduces analysis time as much as 50% for ubiquitin (8.6 kDa, 76 amino acids) FTICR MS and MS/MS spectra at the reliability (RL) value = 0.90 and five pre-selected charge states with minimal decreases in data analysis quality (Table 3).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.23-30
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• 2003

This paper analyzes the characteristic of utility connection type solar power generation system which it is available to connect the utility. And the operation characteristic of this system is compared and analyzed when it is operated in the real system. The constructional and operational problem were obtained by that result. Overcoming that defect is that finding the proper place to be well operated and to find the best place for getting the sunshine data. This method could increase the efficiency of the generation system. And more, current OS in operating system and monitoring management couldn't solve the problem so that improving OS and constructing data backup system should be implemented, This paper proposes the plan to solve that defect in the real system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.129-135
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• 2010

This paper suggests a multipath establishing scheme for ad hoc networks. Data paths are established by on-demand manner. Multipath are made as a sequence of route control message exchange at route setup process. Multipath can be used as a backup path or load balancing for data exchange. Proposed scheme uses a one-hop pre-search scheme for establishing multipath between source and destination. When a node selects a next node for route reply, the node finds optimal route by exchanging route information with neighbor nodes. Simulation results show that the proposed multipath scheme has better split characteristics among multipath and higher route survivability at the environment where nodes are moving.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2303-2310
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• 2009

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be attributed to improper operations of protective relays. Especially, it is the most dangerous problem that trips of backup relays by overload. In this paper, a new algorithm of predicting Zone 3 acting time of distance relay is proposed using the real time synchronized data from PMUs on the transmission system when the power system is danger. In the proposed, some part of the power system are outage when some unexpected fault in the power system, the algorithm will monitor the impedance locus of distance relay. At this time, if there is a big change of Impedance locus, the algorithm will calculate the Zone 3 acting time of the distance relay by the over load. In the case studies, the estimation and simulation network have been testified and analysed in Matlab Simulink.