• Title/Summary/Keyword: adaptive training

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Training Adaptive Equalization With Blind Algorithms

  • Namiki, Masanobu;Shimamura, Tetsuya
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1901-1904
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    • 2002
  • A good performance on communication systems is obtained by decreasing the length of training sequence In the initial stage of adaptive equalization. This paper presents a new approach to accomplish this, with the use of a training adaptive equalizer. The approach is based on combining the training and tracking modes, in which the training equalizer is updated by the LMS algorithm with the training sequence and then updated by a blind algorithm. By computer simulations, it is shown that a class of the proposed equalizers provides better performance than the conventional training equalizer.

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The Effect of Exercise Adaptive Training on Motor Function after Experimental brain ischemia in Rats (실험적 뇌허혈로 인한 편마비 흰쥐에서 운동 적응 훈련이 기능 회복에 미치는 영향)

  • Kwon, Young-Shil;Kim, Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.13 no.3
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    • pp.529-535
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    • 2001
  • The purpose of this study was to test that the exercise adaptive training enhance behavioral outcome significantly after focal brain ischemia in rats. After occlusion of middle cerebral artery in rats, they were housed in individual standard cages fur 24 hours. The control group was sacrificed 24 hours after ischemic event. The experimental group I was housed in standard cages for 7days. The experimental group ll was housed in enriched environment and had got exercise adaptive training fur 7days. The rats were examined five motor behavioral tests. In motor behavioral tests :postural reflex test, limb placement test, beam-walking test, rotarod test, horizontal wire test. The outcomes of control group and group I were significantly lower than the group II. The conclusion was that exercise adaptive training induced functional repair.

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Effect of Residual Frequency Offsets on the Performance of Adaptive Equalizers (잔여 주파수 옵셋이 적응 등화기의 성능에 미치는 영향)

  • Kim, Young-Wha;Cho, Sung-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.4E
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    • pp.108-111
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    • 2004
  • This paper has interest in the effect of a fine frequency offset, defined in ITU-T G.225, to the training performance of an adaptive equalizer. This paper uses Hilbert filter in configuring a transmission system model in order to let it get a frequency offset. Also additive white Gaussian noise and band-limited filter are considered. The signal received from the above transmission system applies to an adaptive equalizer with LMS algorithm, and its training procedures are investigated. As a result, we could find that even small fine frequency offset can severely deteriorate training performance of adaptive algorithm.

A BLMS Adaptive Receiver for Direct-Sequence Code Division Multiple Access Systems

  • Hamouda Walaa;McLane Peter J.
    • Journal of Communications and Networks
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    • v.7 no.3
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    • pp.243-247
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    • 2005
  • We propose an efficient block least-mean-square (BLMS) adaptive algorithm, in conjunction with error control coding, for direct-sequence code division multiple access (DS-CDMA) systems. The proposed adaptive receiver incorporates decision feedback detection and channel encoding in order to improve the performance of the standard LMS algorithm in convolutionally coded systems. The BLMS algorithm involves two modes of operation: (i) The training mode where an uncoded training sequence is used for initial filter tap-weights adaptation, and (ii) the decision-directed where the filter weights are adapted, using the BLMS algorithm, after decoding/encoding operation. It is shown that the proposed adaptive receiver structure is able to compensate for the signal-to­noise ratio (SNR) loss incurred due to the switching from uncoded training mode to coded decision-directed mode. Our results show that by using the proposed adaptive receiver (with decision feed­back block adaptation) one can achieve a much better performance than both the coded LMS with no decision feedback employed. The convergence behavior of the proposed BLMS receiver is simulated and compared to the standard LMS with and without channel coding. We also examine the steady-state bit-error rate (BER) performance of the proposed adaptive BLMS and standard LMS, both with convolutional coding, where we show that the former is more superior than the latter especially at large SNRs ($SNR\;\geq\;9\;dB$).

Comprehensive Relevance of AMPK in Adaptive Responses of Physical Exercise, Skeletal Muscle and Neuromuscular Disorders

  • Lee, Jun-Ho
    • Journal of the Korean Society of Physical Medicine
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    • v.13 no.3
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    • pp.141-150
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    • 2018
  • PURPOSE: This study was conducted to understand the adaptive responses of different modes of physical exercises utilizing skeletal muscle and the comprehensive relevance of AMPK signaling that can be activated by physical exercise as a potential molecular target in human health problems such as neuromuscular disorders (NMDs). METHODS: Most of the contents in this review article are based on recent publications concerning the main topics of interest. The reference literatures cited were obtained by basic searches of overseas academic databases such as PubMed and ScienceDirect using EndNote X7.8. RESULTS: The phenotypic adaptive responses of skeletal muscle during endurance- and resistance-based exercise training (ET and RT respectively) appear to be distinct. To explain the adaptive responses in each single mode of exercises (ET, RT) along with combined exercise training (CT), AMPK signaling is proposed as an important molecular link among those differential modes of exercise and a promising molecular target of NMDs. CONCLUSION: Based on the available evidence, intracellular AMPK signaling activated by diverse stimuli including physical exercise can be a potential and promising therapeutic target for the prevention, amelioration or cure of various human health problems including NMDs and may also be beneficial for physical rehabilitation and emergency situations that may elicit acute metabolic stresses.

Fast Millimeter-Wave Beam Training with Receive Beamforming

  • Kim, Joongheon;Molisch, Andreas F.
    • Journal of Communications and Networks
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    • v.16 no.5
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    • pp.512-522
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    • 2014
  • This paper proposes fast millimeter-wave (mm-wave) beam training protocols with receive beamforming. Both IEEE standards and the academic literature have generally considered beam training protocols involving exhaustive search over all possible beam directions for both the beamforming initiator and responder. However, this operation requires a long time (and thus overhead) when the beamwidth is quite narrow such as for mm-wave beams ($1^{\circ}$ in the worst case). To alleviate this problem, we propose two types of adaptive beam training protocols for fixed and adaptive modulation, respectively, which take into account the unique propagation characteristics of millimeter waves. For fixed modulation, the proposed protocol allows for interactive beam training, stopping the search when a local maximum of the power angular spectrum is found that is sufficient to support the chosen modulation/coding scheme. We furthermore suggest approaches to prioritize certain directions determined from the propagation geometry, long-term statistics, etc. For adaptive modulation, the proposed protocol uses iterative multi-level beam training concepts for fast link configuration that provide an exhaustive search with significantly lower complexity. Our simulation results verify that the proposed protocol performs better than traditional exhaustive search in terms of the link configuration speed for mobile wireless service applications.

LMS based Iterative Decision Feedback Equalizer for Wireless Packet Data Transmission (무선 패킷데이터 전송을 위한 LMS기반의 반복결정 귀환 등화기)

  • Choi Yun-Seok;Park Hyung-Kun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.7
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    • pp.1287-1294
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    • 2006
  • In many current wireless packet data system, the short-burst transmissions are used, and training overhead is very significant for such short burst formats. So, the availability of the short training sequence and the fast converging algorithm is essential in the adaptive equalizer. In this paper, the new equalizer algorithm is proposed to improve the performance of a MTLMS (multiple-training least mean square) based DFE (decision feedback equalizer)using the short training sequence. In the proposed method, the output of the DFE is fed back to the LMS (least mean square) based adaptive DEF loop iteratively and used as an extended training sequence. Instead of the block operation using ML (maximum likelihood) estimator, the low-complexity adaptive LMS operation is used for overall processing. Simulation results show that the perfonnance of the proposed equalizer is improved with a linear computational increase as the iterations parameter in creases and can give the more robustness to the time-varying fading.

Efficient Training Sequence Structure for Adaptive Linear Multiuser Detectors in Space-Time Block Coded Multiuser Systems

  • Hwang Hyeon Chyeol;Shin Seung Hoon;Seok Hyun Taek;Lee Hyung Ki;Yoo Dong Kwan;Kwak Kyung Sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.481-489
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    • 2005
  • In this letter, we propose an efficient training sequence structure for adaptive linear multiuser detectors in space-time block coded multiuser systems, by exploiting a particular property of the minimum mean square error multiuser detectors used in these systems. The proposed structure wastes less overall system capacity than the straightforward training structure, without any corresponding loss of performance, as confirmed by the simulation results.

Model based Stress Decision Method (모델 기반의 강세 판정 방법)

  • Kim, Woo-Il;Koh, Hoon;Ko, Han-Seok
    • Speech Sciences
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    • v.7 no.4
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    • pp.49-57
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    • 2000
  • This paper proposes an effective decision method focused on evaluating the 'stress position'. Conventional methods usually extract the acoustic parameters and compare them to references in absolute scale, adversely producing unstable results as testing conditions change. To cope with environmental dependency, the proposed method is designed to be model-based and determines the stressed interval by making relative comparison over candidates. The stressed/unstressed models are then induced from normal phone models by adaptive training. The experimental results indicate that the proposed method is promising, and that it is useful for automatic detection of stress positions. The results also show that generating the stressed/unstressed model by adaptive training is effective.

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Domain-Adaptive Pre-training for Korean Document Summarization (도메인 적응 사전 훈련 (Domain-Adaptive Pre-training, DAPT) 한국어 문서 요약)

  • Hyungkuk Jang;Hyuncheol, Jang
    • Proceedings of the Korea Information Processing Society Conference
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    • 2024.05a
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    • pp.843-845
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    • 2024
  • 도메인 적응 사전 훈련(Domain-Adaptive Pre-training, DAPT)을 활용한 한국어 문서 요약 연구에서는 특정 도메인의 문서에 대한 이해도와 요약 성능을 향상시키기 위해 DAPT 기법을 적용했다. 이 연구는 사전 훈련된 언어 모델이 일반적인 언어 이해 능력을 넘어 특정 도메인에 최적화된 성능을 발휘할 수 있도록 도메인 특화 데이터셋을 사용하여 추가적인 사전 훈련을 진행한다. 구체적으로, 의료, 법률, 기술 등 다양한 도메인에서 수집한 한국어 텍스트 데이터를 이용하여 모델을 미세 조정하며, 이를 통해 얻은 모델은 도메인에 특화된 용어와 문맥을 효과적으로 처리할 수 있음을 보여준다. 성능 평가에서는 기존 사전 훈련 모델과 DAPT를 적용한 모델을 비교하여 DAPT의 효과를 검증했다. 연구 결과, DAPT를 적용한 모델은 도메인 특화 문서 요약 작업에서 성능 향상을 보였으며, 이는 실제 도메인별 활용에서도 유용할 것으로 기대된다.