• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1239-1241
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• 2001

This research addresses a new vehicle detecting scheme which uses MR(Megneto Resistive) sensor. A vehicle detector which includes two MR sensors for detecting car presence and speed, sensor voltage amplifiers, signal processor, microprocessor, RF data transceiver and a simple car moving simulator is constructed. From experimental results with the vehicle detector the proposed vehicle detecting scheme was verified.

• 전력전자학회논문지
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• 제15권3호
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• pp.167-178
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• 2010

영구자석 동기전동기에서 고정자 권선의 단락으로 인해 발생하는 권선 고장을 동작 중 실시간으로 검출할 수 있는 고장 진단 기법을 제시한다. 제안된 기법은 고조파 분석을 통해 q축 전류의 2차 고조파를 관찰함으로서 이루어지며 고장이 없는 정상 조건에서의 고조파 데이터와 비교를 통해서 고장을 판별한다. 임의의 정상 동작 조건에서의 고조파 데이터는 선형 보간법과 몇 개의 사전 측정된 고조파 데이터를 통해서 구해진다. 제안된 고장 검출 기법의 타당성을 입증하기 위해 내부 고정자의 권선 단락이 가능한 전동기가 제작되었으며 전체 구동 시스템과 고조파 분석 알고리즘 및 고장 검출 알고리즘이 DSP TMS320F28335에 의해 구현되어 실험이 수행된다. 제안된 방법은 부가적인 진단 장비를 필요로 하지 않으며 정상 상태 조건만 만족된다면 동작 중 실시간으로 고장을 검출할 수 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.571-575
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• 2001

A protection scheme for hybrid active power filters, which is combined shunt passive filter and small rated series active filter, is presented and analyzed in this paper. The proposed series active power filter operated as a high impedance 'k($\Omega$)' to the fundamental component when over current occurs in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame (SRF) and the third is the method by detecting the input voltage. When the over current occurs in the power distribution system, the proposed scheme protects the series active power filter without additional protection circuits. The validity of proposed protection scheme is investigated through experimental result for the prototype hybrid active power filter system.

• 한국정보과학회논문지:소프트웨어및응용
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• 제26권1호
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• pp.80-80
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• 1999

As Temporal DataBase Systems(TDBSs) manages both the historical versions and the current version of each data item, a temporal transaction may access more data records than atransaction in traditional database systems. Hence, the concurrency control subsystem of temporaldatabase management system should be able to correctly and efficiently detect actual conflicts amongconcurrent temporal transactions while the cost of detecting conflicts is maintained in low levelwithout detecting false conflicts which cause severe degradation of system throughput.In this paper, Two-Level Conflict Detection(TLCD) scheme is proposed for efficient conflictdetection between concurrent temporal transactions in TDBs. In the proposed TLCD scheme, sincechecking conflict between concurrent temporal transactions is performed at two levels, i, e., logicallevel and physical level, conflicts between concurrent temporal transactions are efficiently and correctlydetected,Furthermore, we also evaluate the performance of the proposed TLCD scheme with those oftraditional conflict detection schemes, logical-level conflict detection scheme and physical-level conflictdetection scheme by simulation approach, The result of the simulation study shows that the proposedTLCD scheme outperforms the previous conflict detection schemes with respect to the averageresponse time.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.607-612
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• 2001

Based on the flow characteristics around a piercing cylinder, a free surface-flow velocitmetry which can be used in extremely harsh environment such as molten steel flow was developed. The velocimetry is consisted of finite length cylinder, load detecting elastic plate, electric signal transducer and data acquisition H/W and S/W. Using such a velocimetry, two velocity measurement schemes were established which one is flow resistance detecting scheme and the other is Karman Vortex frequency detecting scheme. For calibration of each scheme, realistic flow water model was used and in followings, detailed calibration processes were explained.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.543-547
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• 2001

A protection scheme for Unified Power Quality Conditioner (UPQC) is presented and analyzed in this paper. The proposed UPQC has the series active power filter operated as a high impedance k($\Omega$) to the fundamentals when short-circuit faults occur in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame(SRF) and the third is the method by detecting the input voltage. When the short-circuit fault occur in the power distribution system, the proposed scheme protects the UPQC without additional protection circuits. The validity of proposed protection scheme is investigated through simulation results.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2004년도 학술발표논문집
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• pp.179-184
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• 2004

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for process quality improvement. SPC reduces process variability by detecting and eliminating special causes of process variation, while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been need for an integrated process control (IPC) procedure which combines the two strategies. This article considers a scheme that simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process disturbance model under consideration is an IMA(1,1) model with a location shift. The EPC part of the scheme adjusts the process, while the SPC part of the scheme detects the occurrence of a special cause. For adjusting the process repeated adjustment is applied by compensating the predicted deviation from target. For detecting special causes the two kinds of exponentially weighted moving average (EWMA) control chart are applied to the observed deviations: One for detecting location shift and the other for detecting increment of variability. It was assumed that the adjustment of the process under the presence of a special cause may change any of the process parameters as well as the system gain. The effectiveness of the IPC scheme is evaluated in the context of the average cost per unit time (ACU) during the operation of the scheme. One major objective of this article is to investigate the effects of the process parameters to the ACU. Another major objective is to give a practical guide for the efficient selection of the parameters of the two EWMA control charts.

• 한국컴퓨터정보학회논문지
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• 제14권9호
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• pp.47-54
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• 2009

웹을 통해 유포되는 악성코드는 다양한 해킹 기법과 혼합되어 진화되고 있지만, 이의 탐지 기법은 해킹 기술의 발전과 신종 악성코드에 제대로 대응하지 못하고 있는 실정이다. 본 논문에서는 악성코드와 이의 유포 특성의 분석에 따라 탐지 시스템이 갖추어야 할 요구사항을 정의하고, 이를 기반으로 HTTP Outbound Traffic을 감시하여 악성코드의 유포를 실시간으로 탐지하는 개선된 탐지 기법을 제안한다. 제안 기법에서는 악성코드를 유포하는 것으로 입증된 HTML 태그와 자바스크립트 코드를 시그니쳐로 IDS에 설정한다. 실제 침입된 환경에서의 검증 분석을 통해 제안 기법이 기존 기법에 비해 요구 사항의 만족에 우수하고 악성코드에 대한 높은 탐지율을 보임을 제시한다.

• 대한의용생체공학회:의공학회지
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• 제2권2호
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• pp.83-88
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• 1981

A method of detecting abnormal spikes occuring in the EEG of subjects suffering from epilepsy is studied. The detection scheme is to take the first derivative of EEG and to determine if it exceed some threshold value. This study is focused on the digital signal processing for detecting abnormal spikes using microcomputer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권7호
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• pp.1831-1853
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• 2012

By sending periodically short bursts of traffic to reduce legit transmission control protocol (TCP) traffic, the low-rate denial of service (LDoS) attacks are hard to be detected and may endanger covertly a network for a long period. Traditionally, LDoS detecting methods mainly concentrate on the attack stream with feature matching, and only a limited number of attack patterns can be detected off-line with high cost. Recent researches divert focus from the attack stream to the traffic anomalies induced by LDoS attacks, which can detect more kinds of attacks with higher efficiency. However, the limited number of abnormal characteristics and the inadequacy of judgment rules may cause wrong decision in some particular situations. In this paper, we address the problem of detecting LDoS attacks and present a scheme based on the fluctuant features of legit TCP and acknowledgment (ACK) traffic. In the scheme, we define judgment criteria which used to identify LDoS attacks in real time at an optimal detection cost. We evaluate the performance of our strategy in real-world network topologies. Simulations results clearly demonstrate the superiority of the method proposed in detecting LDoS attacks.