• 제목/요약/키워드: Adaptation mechanism

검색결과 244건 처리시간 0.023초

열충격 단백질의 신경정신의학적 의의와 중요성 (Heat Shock Proteins as Molecular Chaperons in Neuropsychiatry)

  • 오동훈;양병환;최준호
    • 생물정신의학
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    • 제14권4호
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    • pp.221-231
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    • 2007
  • Recent researches have shown that important cellular-based autoprotective mechanisms are mediated by heat-shock proteins(HSPs), also called 'molecular chaperones'. HSPs as molecular chaperones are the primary cellular defense mechanism against damage to the proteome, initiating refolding of denatured proteins and regulating degradation after severe protein damage. HSPs also modulate multiple events within apoptotic pathways to help sustain cell survival following damaging stimuli. HSPs are induced by almost every type of stresses including physical and psychological stresses. Our nervous system in the brain are more vulnerable to stress and damage than any other tissues due to HSPs insufficiency. The normal function of HSPs is a key factor for endogenous stress adaptation of neural tissues. HSPs play an important role in the process of neurodevelopment, neurodegeneration, and neuroendocrine regulation. The altered function of HSPs would be associated with the development of several neuropsychiatric disorders. Therefore, an understanding of HSPs activities could help to improve autoprotective mechanism of our neural system. This paper will review the literature related to the significance of HSPs in neuropsychiatric field.

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Proxy Design for Improving the Efficiency of Stored MPEG-4 FGS Video Delivery over Wireless Networks

  • Liu, Feng-Jung;Yang, Chu-Sing
    • Journal of Communications and Networks
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    • 제6권3호
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    • pp.280-286
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    • 2004
  • The widespread use of the Internet and the maturing of digital video technology have led to an increase in various streaming media application. However, new classes of hosts such as mobile devices are gaining popularity, while the transmission became more heterogeneous. Due to the characteristics of mobile networks such as low speed, high error bit rate, etc., the applications over the wireless channel have different needs and limitations from desktop computers. An intermediary between two communicating endpoints to hide the heterogeneous network links is thought as one of the best approaches. In this paper, we adopted the concept of inter-packet gap and the sequence number between continuously received packets as the error discriminator, and designed an adaptive packet sizing mechanism to improve the network efficiency under varying channel conditions. Based on the proposed mechanism, the packetization scheme with error protection is proposed to scalable encoded video delivery. Finally, simulation results reveal that our proposed mechanism can react to the varying BER conditions with better network efficiency and gain the obvious improvement to video quality for stored MPEG-4 FGS video delivery.

이주민 배제 생성 기제에 대한 연구 -상층부 연구접근- (A study of the creation mechanism of exclusion against the immigrant)

  • 김영숙
    • 사회복지연구
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    • 제44권2호
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    • pp.5-33
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    • 2013
  • 본 연구는 상층부 연구로서 한국적 상황에서 이주민들에 대한 차별과 편견을 생성하는 사회적 기제를 분석하고자 했다. 질적연구방법인 생애사 연구로 접근했다. 연구에는 반 다문화적 성향이 강한 한국인 10명이 참여했다. 자료는 심층면담을 통해 수집했고 수집된 자료를 기초로 개별 생애사 텍스트를 구성했다. 생애사 텍스트는 Mandelbaum(1973)이 제안한 분석틀에 의거하여 삶의 영역, 전환점, 적응을 분석했다. 연구결과는 다음과 같다. 연구자는 이주민 배제의 생성기제로 ① 동일지평의 기획, ② 새로운 희생양 찾기, ③ 열등감의 전이를 제시했다. 연구결과에 근거하여 연구자는 「교차문화교육」, 「내국인들이 참여하는 통합프로그램」, 「이주민들과 내국인들의 갈등을 조절하는 지역사회차원에서의 거점센터 설치와 전문인력 양성」을 제안했다.

성능 향상을 위한 퍼지 논리 기반 DASH 알고리즘의 수정 (A Modification of The Fuzzy Logic Based DASH Adaptation Algorithm for Performance Improvement)

  • 김현준;손예슬;김준태
    • 방송공학회논문지
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    • 제22권5호
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    • pp.618-631
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    • 2017
  • 본 논문에서는 시변 네트워크 상황에서 끊김 없는 미디어 서비스를 제공 할 수 있는 퍼지 논리 기반 DASH 적응 알고리즘(FDASH)의 수정을 제안한다. 제안하는 알고리즘은 퍼지 논리 제어부(FLC : Fuzzy Logic Controller)의 수정을 통하여 다음 요청 할 세그먼트의 비트율에 대해 최적의 판단을 하도록 하고, 세그먼트 비트율 필터링 모듈(SBFM : Segment Bit-rate Filtering Module)을 적용하여 비디오 화질의 변화 횟수를 줄인다. 또한, 스트리밍 서비스를 시작 할 때 사용자들이 일정시간 저화질의 비디오를 시청해야 하는 상황을 막는 시작 메커니즘(Start Mechanism)과 버퍼의 오버플로우를 방지하는 대기 메커니즘(Sleeping Mechanism)을 포함한다. 최종적으로 제안된 알고리즘이 FDASH에 비해 좋은 성능을 가짐을 NS-3를 이용한 모의실험을 통해 검증한다. 모의실험 결과, 제안된 방식이 FDASH에 비해 제한된 버퍼크기 상황 하에서도 버퍼 언더플로우/오버플로우가 발생하지 않음을 확인하였다. 또한 점대점(Point-to-Point) 환경과 Wi-Fi환경에서 거의 동일 화질 성능을 보이면서도 비디오 화질 변화 횟수를 50% 이상 줄일 수 있음을 확인하였다.

북한이탈주민의 문화적응 스트레스와 대처기전 (A Study on Acculturation Stress and Stress-coping among North Korean Defectors)

  • 김종경;양영희
    • 성인간호학회지
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    • 제23권1호
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    • pp.50-59
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    • 2011
  • Purpose: This study investigated the degree of acculturation stress among North Korean Defectors and the coping method that they used to deal with it. Methods: Ninety-nine participants of this study were North Korean Defectors in Seoul and Daejeon. The tools of survey for this study were acculturation stress and stress-coping. Results: The score for acculturation stress among North Korean Defectors was $2.97{\pm}0.47$ which was a moderate level of stress. The score of problem-solving coping was $3.10{\pm}0.47$ and emotional coping got $2.85{\pm}0.52$. On acculturation stress, there were higher scores among people who were old-aged, married, low educational levels, dissatisfied with job, low monthly income, and living alone. On problem-solving coping, there were higher score among people who have jobs. Regarding emotional coping, there were higher score in people who have jobs, dissatisfaction with job, and living alone. The higher the problem-solving coping skill, the less the acculturation stress. Conclusion: Reducing of acculturation stress and increasing adaptation mechanism of North Korean Defectors are very important due to the results of this study. Therefore, adaptation programs like psycho-social counseling should be created for North Korean Defectors.

체표 온도 변화에 대한 문헌 고찰 (A literature study on change of surperficial temperature)

  • 김상록;이창훈;조정훈;장준복;이경섭
    • 대한한방체열의학회지
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    • 제4권1호
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    • pp.54-60
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    • 2005
  • Object: A study on the changes of superficial temperature as the ambient temperature varies. Method: After performing research on the physiologic mechanism of heat loss from skin, heat transfer to skin and heat productions of body, the conclusions would be drawn from experiments on temperature changes in every parts of the body as ambient temperature varies . Result and conclusion: Superficial temperature is in equilibrium with ambient temperature after a certain period. Part of the body with big change in superficial temperature tends to have slower temperature change and longer time for adaptation than the part with small change in superficial temperature. The temperature difference between left and right side of the body needs no attention. If adequate adaptation time, a short-period living supervision prior to measurements and appropriate indoor environment management are provided, meaningful conclusion would be attained for infrared thermal diagnosis.

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Toxicological Relevance of Transporters

  • Maeng, Han-Joo;Chung, Suk-Jae
    • Toxicological Research
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    • 제23권1호
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    • pp.1-9
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    • 2007
  • Transporters are membrane proteins that mediate the transfer of substrate across the cellular membrane. In this overview, the characteristics and the toxicological relevance were discussed for various types of transporters. For drug transporters, the overview focused on ATP-binding cassette transporters and solute carrier family 21A/22A member transporters. Except for OCTN transporters and OATP transporters, drug transporters tend to have broad substrate specificity, suggesting drug-drug interaction at the level of transport processes (e.g., interaction between methotrexate and non-steroidal anti-inflammatory agents) is likely. For metal transporters, transporters for zinc, copper and multiple metals were discussed in this overview. These metal transporters have comparatively narrow substrate specificity, except for multiple metal transporters, suggesting that inter-substrate interaction at the level of transport is less likely. In contrast, the expressions of the transporters are often regulated by their substrates, suggesting cellular adaptation mechanism exists for these transporters. The drug-drug interactions in drug transporters and the cellular adaptation mechanisms for metal transporters are likely to lead to alterations in pharmacokinetics and cellular metal homeostasis, which may be linked to the development of toxicity. Therefore, the transporter-mediated alterations may have toxicological relevance.

유도전동기 속도 제어를 위한 뉴로 자기 동조 퍼지 제어기 개발 (Development of a self-Tuning fuzzy controller for the speed control of an induction motor)

  • 김도한;한진욱;이창구
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.248-252
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    • 2003
  • This paper has a control method proposed for the effective self-tuning fuzzy speed control based on neural network of the induction motor indirect vector control. The vector control of an induction motor provides the decoupled control of the rotor flux magnitude and the torque producing current to performance is desirable. But, the drive performance often degrades for the machine parameter variations and its condition give rise to coupling of flux and torque current. The fuzzy speed control of an induction motor has the robustness about machine parameter variations compared with conventional PID speed control in a way. That proved to be some waf from the true. The purpose of this paper is to improve the adaptation by offering self-turning function to fuzzy speed controller. In this paper, the adaptive mechanism of fuzzy speed control in used ANN(Artificial Neural Network) technique is applied in an IFO induction machine drive, such that the machine can follow a reference model (an ideal field oriented machine) to achieve desired speed. In this paper proved the self-turning method of fuzzy controller has the robustness about parameter variation and the wide range of adaptation by simulation.

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선형시변 시스템 기준 모델 적응제어에 관한 고찰 (A Study on the Linear Time-Varying System of MRAC)

  • 구탁모;신장규;김채영
    • 대한전자공학회논문지
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    • 제21권4호
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    • pp.78-83
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    • 1984
  • Hyperstability 이론에 의한 연속시간 시스템의 제어 알고리즘을 이산시간 선형시변 시스템의 적응제어에 직접 이용하여 시스템의 설계를 간단하게 하였다. 기준인력으로서 계단함수와 램프함수를 인가하여 설계된 시스템의 동작특성을 조사해 본 결과 공정의 출력이 모델의 출력에 적응함을 알 수 있었다.

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포화 저항망을 이용한 광적응 윤곽 검출용 시각칩 (A light-adaptive CMOS vision chip for edge detection using saturating resistive network)

  • 공재성;서성호;김정환;신장규;이민호
    • 센서학회지
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    • 제14권6호
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    • pp.430-437
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    • 2005
  • In this paper, we proposed a biologically inspired light-adaptive edge detection circuit based on the human retina. A saturating resistive network was suggested for light adaptation and simulated by using HSPICE. The light adaptation mechanism of the edge detection circuit was quantitatively analyzed by using a simple model of the saturating resistive element. A light-adaptive capability of the edge detection circuit was confirmed by using the one-dimensional array of the 128 pixels with various levels of input light intensity. Experimental data of the saturating resistive element was compared with the simulated results. The entire capability of the edge detection circuit, implemented with the saturating resistive network, was investigated through the two-dimensional array of the $64{\times}64$ pixels