• Structural Engineering and Mechanics
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• 제34권1호
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• pp.97-107
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• 2010

Nonlinear thermoelastic static response characteristics of laminated composite conical panels are studied employing finite element approach based on first-order shear deformation theory and field consistency principle. The nonlinear governing equations, considering moderately large deformation, are solved using Newton-Raphson iterative technique coupled with the adaptive displacement control method to efficiently trace the equilibrium path. The validation of the formulation for mechanical and thermal loading cases is carried out. The present results are found to be in good agreement with those available in the literature. The adaptive displacement control method is found to be capable of handling problems with multiple snapping responses. Detailed parametric study is carried out to highlight the influence of semicone angle, boundary conditions, radius-to-thickness ratio and lamination scheme on the nonlinear thremoelastic response of laminated cylindrical and conical panels.

• Radiation Oncology Journal
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• 제17권4호
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• pp.307-313
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• 1999

목적 : 방사선에 의한 apoptosis 유도에 저선량 방사선이 미치는 영향을 관찰하여 adaptive response 현상이 관계되는지를 마우스 종양에서 분석하고 관련되는 기전에 관하여 연구하고자 하였다. 대상 및 방법 : 마우스 동종암인 HCa-I, OCa-I에서 저선량 (0.05 Gy) 방사선 조사 후 고선량 (25 Gy)을 조사하여 이로부터 일정시간 후 종양에서 유도된 apoptosis 수준을 비교분석하였다. 또한, apoptosis의 조절 물질인 p53, Bcl-2, Bax, Bcl-X 등의 발현을 Western blotting으로 분석하여 관련된 기전을 연구하였다. 결과 : OCa-l에서 0.05 Gy를 전처치 후에 25 Gy를 조사한 군에서 apoptosis의 유도 수준은 세포 1000개당 229로서 예상되는 값인 324 에 비하면 약 $30\%$정도 감소된 결과로 나타나서(p<0.05) 저선량의 방사선에 의하여 apoptosis의 유도 수준이 감소한 것으로 나타났다. 반면 HCa-l기에서는 예상된 apoptosis수준과 실제 관찰치간에 변화가 없었다. 유전물질의 발현에서 p53은 두 종양 공히 0.05 Gy 조사군, 25 Gy 조사군 및 0.05+25 Gy 조사군에서 발현이 증가되었다. Bcl-2와 Bax는 두 종양 모두 발현 수준의 등락이 현저하지는 않았으나 OCa-l의 0.05+25 Gy 조사군에서 Bcl-2의 발현이 Bax를 상회하는 결과를 보였다. Bcl-X는 HCa-l에서 0.05 Gy 정도의 저선량에서부터 높은 상승을 보인 반면, OCa-l기에서는 천혀 발현되지 않았다. 결론 : 마우스 종양의 일부에서 0.05 Gy의 저선량이 고선량 방사선에 의한 apoptosis 유도에 대하여 adaptive response를 보이는 것으로 나타났다. 이는 Bcl-2, Bax의 발현 수준과 BcI-X 등이 관련되는 것으로 보였다. 본 연구는 방사선에 의한 apoptosis에서 adaptive response의 관련성이 일정치 않다는 것을 마우스 종양에서 보여주었다.

• Journal of Plant Biotechnology
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• 제4권2호
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• pp.53-58
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these "environmental or abiotic stresses", which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity, In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.n factors.

• Journal of Advanced Marine Engineering and Technology
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• 제3권1호
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• pp.19-31
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• 1979

Recently the adaptive control system, which keeps the control system always optimal by adjusting the control parameters automatically according to the variations of the plant parameters, have become very important in the field of control engineering. The adaptive control systems are usally composed of the plant identification, the decision of the optimal control parameters, and the adjustment of the control parameters. This paper deals with a method of the adaptive control system when PI or PID controller is used in the feed back control system. Its controlled object (the plant) is assumed to be described by the transfer function of $\frac{ke^{-LS}}{1+TS}$ where k, T and L are steady state gain, time constant and pure dead time respectively, and their values are variable in accordance with the change of environmental circumstance. It has been known that a pseudo-random binary signal is quite effective for the measurement of an impulse response of a plant. In adaptive control systems, however, the impulse response itself is not appropriate to determine the control parameters. In this paper, the authors propose a method to estimate directly the parameters of the plant k, T and L by means of the correlation technique using 3 level M-sequence signal as a test signal. The authors also propose a method to determine the optimal parameters of the PI or PID controller in the sense of minimizing the square integral of the control error in the feed back control system, and the values of the optimal parameters are computed numerically for various values of T and L, and the results are examined and compared with those of the conventional methods. Finally the above-mentioned two methods are combined and an algorithm to struct an adaptive control system is suggested. The experiments for the indicial responses by means of both the model of the temperature control system using SCR actuater and the analog simulations have shown good results as expected, and the effectiveness of the proposed method is verified. The M-sequence generator and the time delay circuit, which are manufactured for the experiments, are operated in quite a good condition.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.561-581
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• 2017

Bayesian statistics can play a key role in the design and analysis of clinical trials and this has been demonstrated for medical device trials. By 1995 Bayesian statistics had been well developed and the revolution in computing powers and Markov chain Monte Carlo development made calculation of posterior distributions within computational reach. The Food and Drug Administration (FDA) initiative of Bayesian statistics in medical device clinical trials, which began almost 20 years ago, is reviewed in detail along with some of the key decisions that were made along the way. Both Bayesian hierarchical modeling using data from previous studies and Bayesian adaptive designs, usually with a non-informative prior, are discussed. The leveraging of prior study data has been accomplished through Bayesian hierarchical modeling. An enormous advantage of Bayesian adaptive designs is achieved when it is accompanied by modeling of the primary endpoint to produce the predictive posterior distribution. Simulations are crucial to providing the operating characteristics of the Bayesian design, especially for a complex adaptive design. The 2010 FDA Bayesian guidance for medical device trials addressed both approaches as well as exchangeability, Type I error, and sample size. Treatment response adaptive randomization using the famous extracorporeal membrane oxygenation example is discussed. An interesting real example of a Bayesian analysis using a failed trial with an interesting subgroup as prior information is presented. The implications of the likelihood principle are considered. A recent exciting area using Bayesian hierarchical modeling has been the pediatric extrapolation using adult data in clinical trials. Historical control information from previous trials is an underused area that lends itself easily to Bayesian methods. The future including recent trends, decision theoretic trials, Bayesian benefit-risk, virtual patients, and the appalling lack of penetration of Bayesian clinical trials in the medical literature are discussed.

• 한국음향학회지
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• 제38권2호
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• pp.145-153
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• 2019

적응빔형성 기법은 부엽을 줄이고 약한 신호에 대한 탐지 성능을 향상시킨다. MVDR(Minimum Variance Distortionless Response)과 같은 일반적인 적응빔형성 기법은 설계한 가중벡터와 실제 입사신호의 조향벡터의 불일치에 대해 매우 민감하다. 또한 센서 수가 많은 어레이를 이용하여 광대역 적응빔형성을 할 경우 공분산행렬을 산출하기 위해 긴 관측시간과 많은 연산량이 요구된다. 본 논문은 센서 수가 많은 수동 선배열 소나의 광대역 적응빔형성 성능향상 및 안정성을 위해 WBRCB(Wideband Robust Capon Beamforming)를 적용하였다. 불일치 요소에 강인한 WBRCB 구현을 위해 다양한 불일치 요소를 반영하여 최적의 불일치 파라미터를 도출하였다. 도출된 파라미터를 반영한 WBRCB 기법을 시뮬레이션 및 실험데이터에 적용하여 수동 선배열 소나의 광대역 적응빔형성 성능 향상을 검증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1132-1136
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• 2005

In this paper, adaptive equalizer receiver for a turbo code direct sequence code division multiple access (DSCDMA) by using least mean square (LMS) adaptive algorithm is presented. The proposed adaptive equalizer is using soft output of decision feedback adaptive equalizer (DFE) to examines the output of the equalizer and the Log- maximum a posteriori (Log-MAP) algorithm for the turbo decoding process of the system. The objective of the proposed equalizer is to minimize the bit error rate (BER) of the data due to the disturbances of noise and intersymbol interference (ISI)phenomenon on the channel of the DS-CDMA digital communication system. The computer program simulation results shown that the proposed soft output decision feedback adaptive equalizer provides a good BER than the others one such as conventional adaptive equalizer, infinite impulse response adaptive equalizer.

• 제어로봇시스템학회논문지
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• 제13권1호
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• pp.19-25
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• 2007

The MFC(Mass Flow Controller) is an equipment that measures and controls mass flow rates of fluid. Most of the HFC system is still using the PID algorithm. The PID algorithm shows superior performance on the MFC system. But the PID algorithm in the MFC system has a few problems as followed. The characteristic of the MFC system is changed according to the operating environment. And, when the piezo valve that uses the control valve is assembled in the MFC system, a coupling error is generated. Therefore, it is very difficult to find out the exact parameters of MFC system. In this paper, we propose adaptive PID algorithm in order to compensate these problems of a traditional PID algorithm. The adaptive PID algorithm estimates the parameters of MFC system using LMS(Least Mean Square) algorithm and calculates the coefficients of PID controller. Besides, adaptive PID algorithm shows better transient response because adaptive PID algorithm includes a feedforward. And we implement MFC system using proposed adaptive PID algorithm with self-tuning and Ziegler and Nickels's method. Finally, comparative analysis of the proposed adaptive PID and the traditional PID is shown.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.205-216
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• 2020

This study seeks to empirically analyze the effects of core self-evaluation and adaptive selling behavior on sales performance for female salespersons engaged in door-to-door sales through the face-to-face channel in the wellness industry. This study seeks to examine the importance of adaptive selling, through, salespeople derive appropriate strategies in response to market changes. For female salespeople who use face-to-face channels, this study empirically investigated the relationship between core self-evaluation and adaptive selling, and effects on sales performance. A 31-item survey was constructed, based on prior research. We selected six door-to-door sales companies in South Korea and conducted one-to-one interviews with female salespeople in the Seoul metropolitan area and analyzed 208 pieces of significant data. Results demonstrated that among the core self-evaluation factors for female salespeople, self-esteem, self-efficacy, and neuroticism had an effect on adaptive selling factors, while locus of control did not. These factors were found to affect sales performance through the mediating role of adaptive selling. Improvements in the adaptive selling capabilities of female salespeople in charge of face-to-face channels positively affected sales performance. Management efforts are required to enhance self-esteem, self-efficacy, or neuroticism. These results suggest that companies should support enhancing individual adaptive selling capabilities of their salespeople.

• 전기학회논문지
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• 제56권9호
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• pp.1676-1679
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• 2007

In control of the time delay systems, if the disturbance information can be estimated exactly, the ideal response for the disturbance can be achieved. Therefore, in this paper, a new adaptive disturbance observer for the time delay system control is proposed. The disturbance observer is designed and adaptive laws for adjusting the observer are proposed. The new Smith predictor controller to eliminate the effects of the disturbance can be achieved by adding an estimated disturbance to the Smith model. The improved performances of the proposed system and the adaptive disturbance observer are verified by computer simulation.