• Title/Summary/Keyword: response variability

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Consideration on new research direction in marine environmental sciences in relation to climate change (기후변화에 대비한 환경연구의 방향)

  • Kim, Su-Am
    • Journal of Environmental Policy
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    • v.1 no.1
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    • pp.1-24
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    • 2002
  • Due to the recent increase in greenhouse gases in atmosphere, world climate is rapidly changing and in turn, the earth ecosystem responds upon the climate changes. Comparing the ecosystem in the past, the present shapes of ecosystem is the result of the serious modification. Fishery resources in marine ecosystem, which usually occupy the upper trophic level, are also inevitable from such changes, because they always react to the natural environmental conditions. The northwestern Pacific is the most productive ocean in the world producing about 30% of world catch. From time to time, however, it has been notified that abundance, distribution and species composition of major fish species were altered by climate events. Furthermore, primary productivity of the ocean is not stable under the changing environments, so that carrying capacity of the ocean varies from one climate regime to another. Major climate events such as global warming, atmospheric circulation pattern, climate regime shift in the North Pacific, and El Nino event in the Pacific tropical waters were introduced in relation to fisheries aspects. The current status and future projection of fishery production was investigated, especially in the North Pacific including Korean waters. This new paradigm, ecosystem response to environmental variability, has become the main theme in marine ecology and fishery science, and the GLOBEC-type researches might provide a solution far cause-effect mechanism as well as prediction capability. Ecosystem management principles for multi-species should be adopted for better understanding and management of ecosystem.

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Hadley Circulation Strength Change in Response to Global Warming: Statistics of Good Models

  • Son, Jun-Hyeok;Seo, Kyong-Hwan
    • Atmosphere
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    • v.26 no.4
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    • pp.665-672
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    • 2016
  • In this study, we examine future changes in the Hadley cell (HC) strength using CMIP5 climate change simulations. The current study is an extension of a previous study by Seo et al. that used all 30 available models. Here, we select 18-23 well-performing models based on their significant internal sensitivity of the interannual HC strength variation to the latitudinal temperature gradient variation. The model projections along with simple scaling analysis show that the inter-model variability in the HC strength change is a result of the inter-model spread in the meridional temperature gradient across the subtropics for both DJF and JJA, not by the tropopause height or gross static stability change. The HC strength is expected to weaken significantly during DJF, while little change is expected in the JJA HC strength. Compared to the calculations with all model members, selected model statistics increase the linear correlation between the changes in HC strength and meridional temperature gradient by 13~23%, confirming the robust sensitivity of the HC strength to the meridional temperature gradient. Two scaling equations for the selected models predict changes in HC strength better than all-member predictions. In particular, the prediction improvement in DJF is as high as 30%. The simple scaling relations successfully predict both the ensemble-mean changes and model-to-model variations in the HC strength for both seasons.

Hypothermia Regulates Endoplasmic Reticulum (ER) Stress through the X-box Binding Protein-1 (XBP1) Gene Expression in PC12 Cells

  • Yoo, Bo-Kyung;Kwon, Kisang;Lee, Eun Ryeong;Kwon, O-Yu
    • Biomedical Science Letters
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    • v.23 no.4
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    • pp.416-420
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    • 2017
  • Endoplasmic reticulum (ER) stress induces unfolded protein response (UPR) via inositol-requiring enzyme 1 (IRE1) activation, which sends a molecular signal for X box-binding protein 1 (XBP1) mRNA splicing in the cytosol. IRE1 endoribonuclease activity induces cleavage of XBP1 mRNA. The XBP1 mRNA is then ligated by an uncharacterized RNA ligase and translated to produce spliced XBP1 by 23 nt removed in which contains the PstI restriction enzyme site. The splicing of XBP1 mRNA can be detected by semiquantitative RT-PCR, and then splicing of XBP1 is a useful tool to measure the genetic variability in ER stress. In this study, we have estimated IRE1-dependent splicing of XBP1 mRNA under conditions of various hypothermia. The results indicated that hypothermia regulated ER stress. This study demonstrated that hypothermia is closely related to ER stress and may be useful for early diagnosis of ER-associated disease.

Regulation of Pharmacogene Expression by microRNA in The Cancer Genome Atlas (TCGA) Research Network

  • Han, Nayoung;Song, Yun-Kyoung;Burckart, Gilbert J.;Ji, Eunhee;Kim, In-Wha;Oh, Jung Mi
    • Biomolecules & Therapeutics
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    • v.25 no.5
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    • pp.482-489
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    • 2017
  • Individual differences in drug responses are associated with genetic and epigenetic variability of pharmacogene expression. We aimed to identify the relevant miRNAs which regulate pharmacogenes associated with drug responses. The miRNA and mRNA expression profiles derived from data for normal and solid tumor tissues in The Cancer Genome Atlas (TCGA) Research Network. Predicted miRNAs targeted to pharmacogenes were identified using publicly available databases. A total of 95 pharmacogenes were selected from cholangiocarcinoma and colon adenocarcinoma, as well as kidney renal clear cell, liver hepatocellular, and lung squamous cell carcinomas. Through the integration analyses of miRNA and mRNA, 35 miRNAs were found to negatively correlate with mRNA expression levels of 16 pharmacogenes in normal bile duct, liver, colon, and lung tissues (p<0.05). Additionally, 36 miRNAs were related to differential expression of 32 pharmacogene mRNAs in those normal and tumorigenic tissues (p<0.05). These results indicate that changes in expression levels of miRNAs targeted to pharmacogenes in normal and tumor tissues may play a role in determining individual variations in drug response.

Reliability-based design of semi-rigidly connected base-isolated buildings subjected to stochastic near-fault excitations

  • Hadidi, Ali;Azar, Bahman Farahmand;Rafiee, Amin
    • Earthquakes and Structures
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    • v.11 no.4
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    • pp.701-721
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    • 2016
  • Base isolation is a well-established passive strategy for seismic response control of buildings. In this paper, an efficient framework is proposed for reliability-based design optimization (RBDO) of isolated buildings subjected to uncertain earthquakes. The framework uses reduced function evaluations method, as an efficient tool for structural reliability analysis, and an efficient optimization algorithm for optimal structural design. The probability of failure is calculated considering excessive base displacement, superstructure inter-storey drifts, member stress ratios and absolute accelerations of floors of the isolated building as failure events. The behavior of rubber bearing isolators is modeled using nonlinear hysteretic model and the variability of future earthquakes is modeled by applying a probabilistic approach. The effects of pulse component of stochastic near-fault ground motions, fixity-factor of semi-rigid beam-to-column connections, values of isolator parameters, earthquake magnitude and epicentral distance on the performance and safety of semi-rigidly connected base-isolated steel framed buildings are studied. Suitable RBDO examples are solved to illustrate the results of investigations.

System identification of a super high-rise building via a stochastic subspace approach

  • Faravelli, Lucia;Ubertini, Filippo;Fuggini, Clemente
    • Smart Structures and Systems
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    • v.7 no.2
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    • pp.133-152
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    • 2011
  • System identification is a fundamental step towards the application of structural health monitoring and damage detection techniques. On this respect, the development of evolved identification strategies is a priority for obtaining reliable and repeatable baseline modal parameters of an undamaged structure to be adopted as references for future structural health assessments. The paper presents the identification of the modal parameters of the Guangzhou New Television Tower, China, using a data-driven stochastic subspace identification (SSI-data) approach complemented with an appropriate automatic mode selection strategy which proved to be successful in previous literature studies. This well-known approach is based on a clustering technique which is adopted to discriminate structural modes from spurious noise ones. The method is applied to the acceleration measurements made available within the task I of the ANCRiSST benchmark problem, which cover 24 hours of continuous monitoring of the structural response under ambient excitation. These records are then subdivided into a convenient number of data sets and the variability of modal parameter estimates with ambient temperature and mean wind velocity are pointed out. Both 10 minutes and 1 hour long records are considered for this purpose. A comparison with finite element model predictions is finally carried out, using the structural matrices provided within the benchmark, in order to check that all the structural modes contained in the considered frequency interval are effectively identified via SSI-data.

Correlation between Real-Time and Off-Time Subjective Assessments and Physiological Responses for Visual Picture Stimulus (시각자극에 대한 실시간 및 비 실시간 주관적 평가와 생리반응과의 상관관계)

  • Jeong, Sun-Cheol;Min, Byeong-Chan;Min, Byeong-Un;Kim, Sang-Gyun;O, Ji-Yeong;Kim, Yu-Na;Kim, Cheol-Jung;Park, Se-Jin
    • Journal of the Ergonomics Society of Korea
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    • v.18 no.3
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    • pp.27-39
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    • 1999
  • The purpose of this study was to approve the capability of human sensibility evaluation based on physiological responses and real-time subjective assessments. Three well-trained healthy human subjects were participated in the experiments. We measured physiological responses such as Heart Rate Variability(HRV), Galvanic Skin Response(GSR) and skin temperature under rest and visual stimulation conditions, respectively. Off-time subjective assessments were recorded before and after visual stimulations. Real-time subjective assessments were recorded during visual stimulations. The results of physiological responses and off-time and real-time subjective assessments were quantified and compared. The results showed that the correlation between physiological responses and real-time subjective assessments was high (83%) for both the positive and negative visual stimulation. The correlation between the physiological responses and off-time subjective assessments was high (83%) for the negative visual stimulation but was low (15%) for the positive visual stimulation. Although the current observation is preliminary and requires more careful experimental study, it appears that the correlation between real-time subjective assessment and physiological responses is higher than that of the off-time subjective assessment and physiological responses.

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A CEPHALOMETRIC STUDY OF SOFT TISSUE PROFILE CHANGES ASSOCIATED WITH ORTHODONTIC TREATMENT (Cephalogram 분절(分折)에 의(依)한 부정교합자(不正咬合者) 치료전후(治療前後)의 연조직(軟組織) 측모(側貌) 변화(變化)에 관(關)한 연구(硏究))

  • Park, Young Guk;Lee, Ki Soo
    • The korean journal of orthodontics
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    • v.14 no.1
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    • pp.103-113
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    • 1984
  • This work was undertaken to evaluate the integumental response in lower face to hard tissue changes, and to grope the prediction equation for expected integumental profile changes. Cephalometric headplates of 25 persons consisted of 8 Angle's class 1 maxillary protrusive and 17 Angle's class II division 1 patients whose mean age was 15.2 years were traced, diagramatized, and statistically analyzed. The results were as follows; 1. Upper incisor and lips were retracted and convexity of integumental profile decreased concurrently with decrease of hard tissue procumbency, however soft tissue point A', B', and Pog' did not undergo significant changes after orthodontic treatment. 2. Remarkable increment of upper lip thickness and upper lip height was shown and this was related to upper incisor retraction. The ratio between the amount of upper incisor retraction and the increment o f upper lip thickness was approximately 1.16:1. 3. Moderate correlation of upper lip retraction to upper incisor retraction, and of lower lip retraction to lower incisor movement were arranged, and yet comparatively wide variability from subject to subject was shown. 4. It was possible to predict statistically for horizontal alteration of lip position and change of upper lip angulation ground in orthodontic treatment.

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A STUDY ON THE TIME-VARYING POWER SPECTRUM ESTIMATION ALGORITHM USING TIME-FREQUENCY REPRESENTATION (시주파수 표현에 의한 시변파워스펙트럼 추정 알고리즘에 관한 연구)

  • Lee, Jeong-Whan;Lee, Joon-Young;Lee, Dong-Joon;Kim, Han-Soo;Jeon, Woo-Chul;Lee, Myoung-Ho
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.991-993
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    • 1999
  • This study proposed a new algorithm to assess autonomic function activity using Time-Frequency Representation(TFR). TFR is a way of describing the time-valiant energy of a signal. A discrete Wigner representation that is capable of filtering out any cross terms occuring in the Wigner-Ville Distribution(WVD) is used for time-variant energy distribution of heart rate variability(HRV) signals. And the marginal condition are evaluated to estimate power spectrum of HRV signals. The proposed algorithm showed that estimated power spectrum of HRV signals well describe the autonomic nerve system function and also showed the dynamics of autonomic nervous system response.

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Stochastic Finite Element Analysis by Using Quadrilateral Elements (사변형 요소를 이용한 추계론적 유한요소해석)

  • Choi, Chang Koon;Noh, Hyuk Chun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.5
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    • pp.29-37
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    • 1993
  • The extension of the weighted integral method in the area of stochastic finite element analysis is presented. The use of weighted integral method in numerical analysis was extended to CST(constant strain triangle) element by Deodatis to calculate the response variability of 2D stochastic systems. In this paper, the extension of the weighted integral method for general plane-elements is represented. It has been shown that the same mesh used in the deterministic FE analysis can be used in the stochastic FE analysis. Furthermore, because the CST element is a special case which has constant strain-displacement matrix the mingling of CST elements with the other quadrilateral elements in the analysis may also be possible.

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