• Title/Summary/Keyword: gain adaptation

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Effects of Dietary Lipids and Dexamethasone on Mucosal Hyperplasia after 70% Jejunoileal Resection in Rats (식이지방과 Dexamethasone 주입이 소장절제후 소장 점막의 증식에 미치는 영향)

  • Park, Vanderhoof, J.A.;Yoon, Jung-Han
    • Journal of Nutrition and Health
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    • v.28 no.10
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    • pp.1031-1039
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    • 1995
  • Dietary mehaden oil enhances mucosal hyperplasia that normally occurs after massive small bowel resection. In contrast, dexamethasone and aspirin inhibit the adaptation response. In order to gain insight on the mechanism of these effects, male Sprague-Dawley rats weighing approximately 150gram were randomly divided into two groups and fed diet containing either 15% safflower oil or 14% menhaden oil and 1% safflower oil. Ten days later they were subjected to 70% jejunoilear resection. Immediately after surgery each group was further divided into two groups and receive either vehicle or 125ug/kg/day dexamethasone subcutaneously. All animals were sacrificed seven days after the surgery, and the remaining intestine was removed and divided at the anastomotic site. Dexamethasone, which decreased gut hyperplasia in both dietary groups, decreased both serum IGF-I levels and ileral PGE2 synthesis. Menhaden oil enhanced gut hyperplasia, but did not increase IGF-I or IGF-II levels in serum. PGE2 synthesis was lower in the ileum of menhaden oil-fed rats compared to that of safflower oil-fed rats. The effects of menhaden oil on adaptation did not apper to be mediated either through IGFs or PGE2 synthesis. Other factors could have played a role in enhancing adaptation following menhaden oil feeding.

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Efficient Power and Rate Adaptation Strategy for Improved Spectral Efficiency in Multi-Carrier DS-CDMA Communications (다중 반송파 부호분할 다중접속 통신에서의 주파수 효율 향상을 위한 효율적인 전력 및 전송률 적응화 기법)

  • Lee, Ye Hoon;Kim, Dong Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.697-703
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    • 2013
  • We propose an efficient frequency-time domain resource allocation scheme in multi-carrier (MC) direct-sequence code-division multiple-access (DS/CDMA) communications. We consider, as a power allocation strategy in the frequency domain, transmitting each user's DS waveforms over the user's sub-band with the largest channel gain. We then consider rate adaptation in the time domain, where the data rate is adapted such that a desired transmission quality is maintained. We analyze the achievable average data rate of the proposed scheme with fixed average transmission power, and compare the performance to single carrier DS/CDMA systems with power and rate adaptations.

Design of an Adaptive Fuzzy Controller using Genetic Algorithm (유전알고리즘을 이용한 적응 퍼지 제어기의 설계)

  • Huh, Sung-Hoe;Seo, Ho-Joon;Park, Jang-Hyun;Yun, Pil-Sang;Park, Gwi-Tae
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.530-532
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    • 1999
  • In adaptive fuzzy control, system designer develops an adaptive law for the output of the unknown plant to track a given signal. The adaptation gains of the adaptive law are critical elements in the overall system, however, they were used to be selected by the designer's experience or intuition. In this paper, genetic algorithm is used to search an optimal adaptation gain and simulation results will be presented to show the improved tracking responses.

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A comparative study on the improvement of the robustness in adaptive control systems (적응제어의 강인성개선에 관한 비교연구)

  • 김국헌;김영철;양흥석
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.352-355
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    • 1986
  • In this paper, some candidates suggested for the improvement of the robustness in adaptive control systems are shortly surveyed. Using dead zone concept of error in adaptation process, gain retardation methods such as .sigma.-modification and parameter restriction method are those considered. Feedforward compensation and normalized adaptation technique are also considered. New modeling technique suggested by Donati et al is used for the indirect control of plants containing unmodeled dynamics. The frequency band of input signal, which is used as a test signal and control signal simultaneously, is directly related to the control of plants containing high frequency parastics. Computer simulation results of the some selected algorithms are shown.

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DESIGN OF ADAPTIVE CONTROLLER OF DC SERVO MOTOR (직류전동기의 적응 제어기 설계에 관한 연구)

  • Chang, S.G.;Won, J.S.
    • Proceedings of the KIEE Conference
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    • 1987.11a
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    • pp.25-28
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    • 1987
  • Design procedure of adaptive controller with variable load condition is present and applied to velocity control of small, permanent magnet DC servo motor. The state feedback control scheme is adopted and Recursive Least Squares algorithm is used for parameter estimation. In order to reduce the time consuming. In the procedure of adaptation-gain tuning of state feedback controller, approximate curve fitting technique is applied to the relations between load condition and poles of the system, load condition and feedback gains. With this method, fast adaptation can be accomplished. It is shown that this procedure can be applied not only to variable load condition but also to variation of other system constants, for example variation of resistance and inductance etc.. Simulation results is present for both cases - variable inertia load, variable motor resistance to verify performance improvements. This design procedure produces an adaptive con troller which is feasible for implementation with microprocessor by reducing calculation time.

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Adaptive Channel Coding for Flat Fading Channel (플랫 페이딩 채널에서의 적응 채널 부호화 기술)

  • Asaduzzaman, Asaduzzaman;Kong, Hyung-Yun;Vu, Ha Nguyen
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.157-158
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    • 2008
  • This paper examines an adaptive coding scheme for flat fading channels to maximize the average code rate of a coded system. The proposed adaptation technique is employed by using the required free distance of a rate compatible code depending on the channel realization. First, the system will calculate the required free distance based on the instantaneous channel gain. Based on this channel gain we will select a set of convolution code to optimize the code rate with a certain performance requirement. Simulation results show that our proposal can achieve a higher code rate.

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Coordinated Simultaneous Attitude Pointing for Multiple Satellites Under Formation Flying

  • Choi, Yoon-Hyuk;Lee, Henzeh;Bang, Hyo-Choong
    • International Journal of Aeronautical and Space Sciences
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    • v.8 no.1
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    • pp.129-139
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    • 2007
  • In this paper, attitude control laws for simultaneous pointing of multiple spacecrafts are considered under a formation flying scenario. The basic approach lies in adaptive feedback gains using relative attitude information or maneuver time approximation for coordinated attitude control. Each control law is targeted to balancing mean motion or to correcting system response to the slowest satellite. The control gain adaptation is constructed by two approaches. The first one is using variable damping gain to manipulate speed of a fast system response, and the second one uses alternate natural frequency of the system under control. The validity and stability of the proposed approaches are examined analytically and tested through numerical simulations.

Optimum Uplink Power/Rate Control for Minimum Delay in CDMA Networks

  • Choi, Kwon-Hue;Kim, Soo-Young
    • ETRI Journal
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    • v.25 no.6
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    • pp.437-444
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    • 2003
  • We derive a new joint power and rate control rule with which we can minimize the mean transmission delay in CDMA networks for a given mean transmission power. We show that it is optimal to respectively control the power inverse-linearly and the rate linearly to the square root of channel gain while maintaining the signal-to-interference ratio at a constant. We also show that the proposed joint power/rate control rule achieves excellent performance results in terms of the probability of the instantaneous delay being within a target delay against one-dimensional control schemes.

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High Performance PI Current Controller for a Switched Reluctance Motor

  • Ashoornejad, A.;Rashidi, A.;Saghaeian-nejad, S.M.;Ahn, Jin-Woo
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.4
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    • pp.367-373
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    • 2014
  • The most common current controller for the Switched Reluctance Motor (SRM) is the hysteresis controller. This method, however, suffers from such drawbacks as variable switching frequency, consequent audible noise and high current ripple. These disadvantages make this controlling method undesirable for many applications. The alternative solution is the PI controller. Since the fixed gain PI current controller can only be optimized for one operating point, and on the other hand, SR motor is highly nonlinear, PI controller gain should be adjusted according to incremental inductance. This paper presents a novel method for PI current controller gain adaptation which is simple and yields a good performance. The proposed controller has been implemented on a test bench using a eZdsp F28335 board. The performance of the current controller has been investigated in both simulation and experimental tests using a four-phase 8/6 4KW SRM drive system.

Constitution of Prescription and Medicinal Effect & Adaptation Diseases of 'Bullsoosan(佛手散)' in Korean Medical Books (한국(韓國) 의서(醫書)에 보이는 불수산(佛手散)의 처방구성(處方構成)과 효능(效能)·주치(主治)에 대한 고찰)

  • Lyu, Jeong-ah;Jeong, Chang-hyun
    • Journal of Korean Medical classics
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    • v.29 no.1
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    • pp.17-41
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    • 2016
  • Subjects : A literature research on the constitution and medicinal effect & adaptation diseases of "Bullsusan". "Bullsusan" is a herbal prescription composed of Angelicae Gigantis Radix(當歸) and Cnidii Rhizoma(川芎). Objectives : Through the researching on the records of "Bullsusan" in Korean Traditional Medical Books, gain the literature evidence for adaptation to these days child labor as a pre-labor keeping herbal medicine. And have detailed consideration on the constitution of prescription and medicinal effect & adaptation diseases of "Bullsusan". Methods : First, researched the records of "Bullsusan" in Korean Traditional Medical Books which were included at A Series of Korean Medicine(韓國醫學大系) and analysed component ratio, nickname, herbal manufacture and drug processing method, medicinal effect and adaptation diseases. Second, referred related Korean and Chinese researches that examined the medicinal effect and adaptation diseases of "Bullsusan" by scientific experimentation. Conclusions : We found total 46 records of "Bullsusan" from 20 kinds of Korean Traditional Medical Books included at A Series of Korean Medicine. Prescription component ratio of Angelicae Gigantis Radix and Cnidii Rhizoma were 3:2, 1:1, 2:1, 1:1. 3:2 had most 20 records and 1:1 had second 14 records. Especially 1:1 had a tendency of having nickname "Goonguitang", but not must had. First herbal manufacture was powder, it had 8 records. First drug processing method was decocting with water and alcohol, had 19 records. Medical Effects of "Bullsusan" can be induced to next 8, that were "remove get bad blood, give birth new blood", "easy labor by reducing fetal volume", "acceleration of labor", "test of fetal survival, elimination of dead embryo", "elimination of placenta", "revive", "allaying pain", "nourish the blood". From these medical effects, 9 adaptation diseases can be induced. That were "threatened abortion", "womb ache and vaginal bleeding by spontaneous abortion", "pre-labor keeping(prevention of hard labor)", "acceleration of labor", "hard labor", "missed abortion", "postnatal vaginal bleeding, dizziness, asthma, headache, womb ache", "postnatal mastoptosis and mastodynia", "first aid symptom like as dizziness, unconsciousness, stroke caused by excessive bleeding". The medical effect of "acceleration of labor" and "elimination of placenta" have been examined by modern clinical research. The effect of "remove get bad blood, give birth new blood", "allaying pain" and "nourish the blood" have been examined by modern experimental study. But overdosing on "Bullsusan" to pregnant mouse can cause natural abortion, so the proper dose of "Bullsusan" in pregnant period is very important.