• Electronics and Telecommunications Trends
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• v.23 no.6
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• pp.81-91
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• 2008

CMOS 공정의 가속적인 스케일링에 의해 CMOS 기술은 종래의 마이크론기술에서 나노기술로 변해가고 있다. 이러한 반도체 소자 및 제작기술에 따른 온도와 공정의 변화에 매우 민감한 부분인 아날로그 회로는 설계 초기단계에서 중요한 요소들(이득, 누설 전류, 잡음 및 부정합 등)을 재검토할 필요가 있다. 또한, 나노 CMOS 공정을 사용한 1.0 V 이하의 저전압 동작에서는 아날로그 신호의 동적영역 확보가 어렵고 잡음이 증가하므로 새로운 패러다임을 적용한 혁신적인 아날로그 회로기술 개발이 필요한 실정이다. 이에 따라, 본 고에서는 그린기술(green technology)의 한 요소로서, 나노 CMOS 공정기술을 이용한 1.0 V 이하 전원전압의 저전력 아날로그 회로기술 동향과 관련 특허동향에 대해서 살펴보고자 한다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2218-2220
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• 2003

현대 산업현장에서 80%이상 사용되는 PID(proportional integral derivative) 제어기는 제어성, 적응성, 제어이득 조정 등의 특정이 있어나 제어 대상에 대한 PID 제어 계수를 경험적 방법인 수동으로 동조해야하는 문제점이 있다. 이를 개선하기 위해 본 논문에서 PID제어기의 최적 자동동조를 위한 릴레이 동조 방법을 제안한다. 기존의 한계감도법과 과도응답 법으로 초기계수를 결정하는 방법보다 유연성과 적용성이 높고, 이를 마이크로프로세서(DSP : TMS-320C32)에 적용하여 소프트웨어적으로 릴레이의 기능이 이루어지도록 설계했다. 이는 Ziegler-Nichols 계수조정법이 갖는 적용대상의 제약성을 극복한 방법이며, 릴레이에 의해 출력을 강제 진동시키고 출력의 진폭과 주기를 이용하여 PID 계수를 조정하고, 또 상대안정성의 척도인 위상여유를 고려하므로 시스템의 상대안정성과 견실성을 향상시킬 수 있음을 확인하였다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2137-2139
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• 2003

본 논문에서는 초고속 비동기전송(ATM)망에서의 체증 문제를 풀기위해 $H_{\infty}$ 필터 사용을 제안한다. 많은 제어기들에 대한 초기 연구들은 가용 비트율이 망 체증이 제거될 수 있도록 버퍼에서의 원하는 셀들의 큐의 길이를 원하는 값 범위내에서 성공적으로 조절될 수 있음을 보이고 있다. 본 논문에서는 망의 노이즈를 가우시안 랜덤 열로 근사화하는 ATM망에 대하여 현대 제어 기법인 $H_{\infty}$ 필터를 적용한다. 따라서 제안한 $H_{\infty}$ 필터는 망의 외란으로 밭생하는 망의 출력의 영향을 미리 주어지는 $H_{\infty}$ 노옴값 이내로 유지시켜준다. 따라서 미리 주어지는 $H_{\infty}$ 노옴값이 작다면 제안한 $H_{\infty}$ 필터는 외란에 강인한 성능을 보여줄 수 있다. $H_{\infty}$ 필터 이득은 대수적인 리카티 방정식의 해로 구해진다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.405-406
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• 2019

ICS 해커들의 주요 목적은 재정적 이득, 기업간첩, 테러리스트 활동, 국가간의 사이버전쟁, 잘못된 윤리적 해킹 등의 이유들이 있다. 이에 따른 해킹 경로로는 산업제어 시스템이 공용 인터넷에 노출되는 경우, 기기 초기 설정을 방치, 장기간의 비밀번호 미 변경, 포트스캐닝, 구글 해킹 등이 있다. 이에 따른 대표적인 해킹방식 5 가지가 있는데 첫째, Shodan 을 이용한 일종의 검색해킹, 둘째, ZAP 툴을 이용하여 전수공격을 하는 패스워드 퍼징, 셋째, 목표 사이트의 취약점을 이용하여 인증을 우회하는 공격인 SQL Injection, 넷째, Modbus 툴을 이용한 해당 시설의 전압을 변경하는 네트워크 공격, 다섯째, zbgoodfind 툴을 통한 원격장치공격이 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.155-160
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• 2003

Owing to the advances in ADC and DSP technologies, signals in If band, which once had to be processed in analog technology, can new be digitally processed. This is referred to as "Digital IF" or "Digital Radio", which is a preliminary stage of SDR. Applying the digital radio technology to a multi-carrier receiver design, a processing gain is generated through an over-sampling of input data. In the digital receiver, decimation is performed for reducing the computational complexity CIC and half band filter is used together with the decimation as an anti-alising filter. The CIC filter, however, should introduce the roll-off phenomenon in the passband, which causes the receiving performance to be considerably degraded due to the distorted Passband flatness of receiving filter. In this paper, we designed a CIC roll-off compensation filter for W-CDMA digital receiver. The performance of the proposed compensation filter is confirmed through computer simulations in such a way that the BER is minimized by compensating the roll-off characteristics.off characteristics.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.1
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• pp.65-73
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• 2007

This paper presents an on-line correction method of current measurement errors for a pure-integration-based flux estimation down to 1-Hz stator frequency. An observer-based approach is taken as one possible solution of eliminating the dc offset and the negative sequence component of unbalanced gains in the synchronous coordinate. At the same time, the positive sequence component estimation is performed by creating an error signal between a motor model reference and an estimated q-axis rotor flux established by a permanent magnet (PM) in the synchronous coordinate. The compensator utilizes a PI controller that controls the error signal to zero. The proposed technique further contains a residual error compensator to completely eliminate miscellaneous disturbances in the estimated flux. The developed algorithm has been implemented on a 1.1-kW permanent magnet synchronous motor (PMSM) drive to confirm the effectiveness of the proposed scheme.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.570-575
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• 2021

Since humans live while feeling rich in their five senses, care must be taken not to damage their hearing in order to lead a happy life. Hearing damage suffered in a living environment is common in a partial band where a specific frequency band is first damaged. However, since the initial pain of hearing damage does not appear much, it is difficult to determine the symptoms in the early stages. In this paper, we proposed a high-speed measurement method that can easily and quickly self-measure hearing damage through a simple app. In this method, 9 pure tones compensated for gain for each voice soub-band are alternately heard in both ears, so that one's own hearing damage can be detected at high speed. When 18 tone pulses were heard for 30 seconds per person, 1 out of 12 subjects was identified as suspected of partial hearing damage. And when the test subjects were informed of the hearing determination method for the number of hearings, the participants themselves immediately determined whether their hearing was damaged. This measurement method simply judges the hearing of both ears within 30 seconds with a smart phone, so that hearing measurements that took more than 10 minutes in hospitals are relatively accurate, and it was found that hearing health can be maintained while reducing time and costs.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.191-198
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• 2011

In general, conventional criticality analyses for spent fuel transport/dry storage systems have been performed based on assumption of fresh fuel concerning the potential uncertainties from number density calculation of Transuranic and Fission Products in spent fuel. However, because of economic loss due to the excessive criticality margin, recently the design of transport/dry storage systems with Burnup Credit(BUC) application has been actively developed. The uncertainties in criticality analyses on transport/storage systems with BUC technique show strong dependance upon initial enrichment and burnup rate, whereas those in the conventional criticality evaluation based on fresh fuel assumption do not show such a dependance. In this study, regulatory-required uncertainties of the criticality analyses for BK 26 Cask, which is conceptually designed spent fuel transport cask with BUC corresponding to the limiting circumstances on nuclear power plants in Korea, are evaluated as a function of initial enrichment and burnup rate. Results of this study will be used as basic data for spent fuel loading curve of BK 26 Cask.

• Korean Journal of Ichthyology
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• v.26 no.1
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• pp.11-16
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• 2014

The best spawning timing in a day and the first spawning position of Pseudopungtungia nigra was investigated at the Jujacheon stream in Jinan-gun Jeollabuk-do, Koera from May to July 2009. P. nigra spawned only at the nest of Coreoperca herzi from 7 May to 11 July, 2009. P. nigra spawned at 56 nests among 61 nests of C. herzi, and the spawning of P. nigra started on after 1st or 2nd day spawning of C. herzi. The spawning behavior was dominantly observed at around 06:00 to 07:00 AM, when parental C. herzi males are usually inactive in the territorial defence. The hatching rate of P. nigra eggs was closely related with the parental activity of the guarding C. herzi, and P. nigra deposit their eggs as close as possible to the egg clutches of C. herzi (normally at the perimeter of the clutch), likely to take much of the potential effects from fanning and guarding, as the hosts focus their care on the centre of the egg clutch.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.1
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• pp.57-67
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• 2013

Lately, intrusive incidents (including system hacking, viruses, worms, homepage alterations, and data leaks) have not involved the distribution of an virus or worm, but have been designed to acquire private information or trade secrets. Because an attacker uses advanced intelligence and attack techniques that conceal and alter data in a computer, the collector cannot trace the digital evidence of the attack. In an initial incident response first responser deals with the suspect or crime scene data that needs investigative leads quickly, in accordance with forensic process methodology that provides the identification of digital evidence in a systematic approach. In order to an effective initial response to first responders, this paper analyzes the collection data such as user usage profiles, chronology timeline, and internet data according to CFFPM(computer forensics field triage process model), proceeds to design, and implements a collection application to deploy the client/server architecture on the Windows based computer.