• 제목/요약/키워드: Trial Functions

검색결과 238건 처리시간 0.021초

Weak forms of generalized governing equations in theory of elasticity

  • Shi, G.;Tang, L.
    • Interaction and multiscale mechanics
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    • 제1권3호
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    • pp.329-337
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    • 2008
  • This paper presents the derivation of the generalized governing equations in theory of elasticity, their weak forms and the some applications in the numerical analysis of structural mechanics. Unlike the differential equations in classical elasticity theory, the generalized equations of the equilibrium and compatibility equations presented here take the form of integral equations, and the generalized equilibrium equations contain the classical differential equations and the boundary conditions in a single equation. By using appropriate test functions, the weak forms of these generalized governing equations can be established. It can be shown that various variational principles in structural analysis are merely the special cases of these weak forms of generalized governing equations in elasticity. The present weak forms of elasticity equations extend greatly the choices of the trial functions for approximate solutions in the numerical analysis of various engineering problems. Therefore, the weak forms of generalized governing equations in elasticity provide a powerful modeling tool in the computational structural mechanics.

Genetic algorithm in mix proportion design of recycled aggregate concrete

  • Park, W.J.;Noguchi, T.;Lee, H.S.
    • Computers and Concrete
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    • 제11권3호
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    • pp.183-199
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    • 2013
  • To select a most desired mix proportion that meets required performances according to the quality of recycled aggregate, a large number of experimental works must be carried out. This paper proposed a new design method for the mix proportion of recycled aggregate concrete to reduce the number of trial mixes. Genetic algorithm is adapted for the method, which has been an optimization technique to solve the multi-criteria problem through the simulated biological evolutionary process. Fitness functions for the required properties of concrete such as slump, density, strength, elastic modulus, carbonation resistance, price and carbon dioxide emission were developed based on statistical analysis on conventional data or adapted from various early studies. Then these fitness functions were applied in the genetic algorithm. As a result, several optimum mix proportions for recycled aggregate concrete that meets required performances were obtained.

윌쉬-블록펄스 함수와 최적 LMS알고리즌을 이용한 적응 등화기의 설계 (A Design of Adaptive Equalizer using the Walsh-Block Pulse Functions and the Optimal LMS Algorithms)

  • 안두수;김종부
    • 대한전기학회논문지
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    • 제41권8호
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    • pp.914-921
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    • 1992
  • In this paper, we introduce a Walsh network and an LMS algorithm, and show how these can be realized as an adaptive equalizer. The Walsh network is built from a set of Walsh and Block pulse functions. In the LMS algorithm, the convergence factor is an important design parameter because it governs stability and convergence speed, which depend on the proper choice of the convergence facotr. The conventional adaptation techniques use a fixed time constant convergence factor by the method of trial and error. In this paper, we propose an optimal method in the choice of the convergence factor. The proposed algorithm depends on the received signal and the output of the Walsh network in real time.

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CNN 구조의 진화 최적화 방식 분석 (Analysis of Evolutionary Optimization Methods for CNN Structures)

  • 서기성
    • 전기학회논문지
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    • 제67권6호
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    • pp.767-772
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    • 2018
  • Recently, some meta-heuristic algorithms, such as GA(Genetic Algorithm) and GP(Genetic Programming), have been used to optimize CNN(Convolutional Neural Network). The CNN, which is one of the deep learning models, has seen much success in a variety of computer vision tasks. However, designing CNN architectures still requires expert knowledge and a lot of trial and error. In this paper, the recent attempts to automatically construct CNN architectures are investigated and analyzed. First, two GA based methods are summarized. One is the optimization of CNN structures with the number and size of filters, connection between consecutive layers, and activation functions of each layer. The other is an new encoding method to represent complex convolutional layers in a fixed-length binary string, Second, CGP(Cartesian Genetic Programming) based method is surveyed for CNN structure optimization with highly functional modules, such as convolutional blocks and tensor concatenation, as the node functions in CGP. The comparison for three approaches is analysed and the outlook for the potential next steps is suggested.

The effects of EMG-triggered functional electrical stimulation on upper extremity function in stroke patients

  • Kim, Young
    • Physical Therapy Rehabilitation Science
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    • 제2권1호
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    • pp.1-6
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    • 2013
  • Objective: The aim of this review is to explore the latest intervention trends and effects of EMG-triggered functional electrical stimulation on the upper extremity functions in stroke patients. Design: Systematic review on clinical trials. Methods: A systematic literature search was performed to identify clinical trials evaluating the effects of EMG-triggered functional electrical stimulation (EMG-FES) and task-oriented EMG-triggered FES on the hand functions in stroke patients. Literature review was conducted with the following key words: hand function, functional electrical stimulation, task-oriented, stroke. Results: Ten clinical trials were included; 8 of them were randomized controlled trial, 1 was block-randomized, and 1 was a pre-post comparison study. A positive effect of electrical stimulation was reported in the patient groups that were treated with functional electrical stimulation combined with specific tasks, and volitional muscle contraction-triggered stimulation that was synchronized with tasks. Motor capabilities of the hand and arm were improved after the rehabilitation. Conclusions: EMG-triggered electrical stimulation may be more effective than non-triggered electrical stimulation in facilitating the hand functions in stroke patients in terms of muscle strength and voluntary muscle contraction of the paretic hand and arm. Triggered electrical stimulation can be even more effective when it is combined with specific tasks.

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The effects of treadmill training on dynamic balance and gait function in stroke patients: a pilot randomized controlled trial

  • Chung, Eun Jung;Lee, Byounghee
    • Physical Therapy Rehabilitation Science
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    • 제2권1호
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    • pp.39-43
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    • 2013
  • Objective: The objective of this study is to investigate the effect of treadmill gait trainig on dynamic balance and gait functions in stroke patients. Design: Randomized, double-blind, controlled pilot study. Methods: Four subjects following first stroke participated in this study. They were divided randomly into the treadmill gait trainig group (TM group) (n=2) and the control group (n=2). Subjects in both groups received general training five times per week. Subjects in the TM group practiced an additional treadmill gait trainig program that consisted of 60 minutes, three times per week, during a period of four weeks. Timed up and go test (dynamic balance) and the GAITRite test (gait function) were evaluated before and after the intervention. Results: In dynamic balance (timed up and go test), the TM group (-14.235 sec) showed a greater decrease than the control group (-13.585 sec). In gait functions, the TM group showed a greater increase in gait speed (12.8 cm/s vs. 10.15 cm/s), step-length (5.825 cm vs. 3.735 cm), and stride-length (5.005 cm vs. 1.55 cm) than the control group. Conclusions: The treadmill gait trainig improved dynamic balance and gait functions. Further research is needed in order to confirm the generalization of these findings and to identify which stroke patients might benefit from treadmill gait trainig.

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기관지천식 증상에 대한 마황정천탕의 안전성 유효성 예비 임상 연구 (Clinical Trial of Herbal Medicine Formula Mahwangjeongcheon-tang on Patients with Asthmatic Symptom: A Preliminary Study)

  • 박수정;최나래;김구;유종향;이시우;주종천
    • 사상체질의학회지
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    • 제25권4호
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    • pp.373-383
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    • 2013
  • Objectives The purpose of this clinical trial was evaluate the safety and efficacy of Mahwangjeongcheon-tang (MJT). Methods Twenty six volunteers were recruited as subjects. They were divided into two groups, which were MJT test group and placebo group. The investigated items related to the safety were the weight, the results of renal function and liver function. The investigated items related to the efficacy are the results of the spirometer, the clinical asthma measurement scale in oriental medicine-V (CAMSOM-V) and the quality of life questionnaire for adult Korean asthmatics (QLQAKA). Results There are no difference in the weight, the results of the renal functions and the liver functions between MJT test group and placebo group. There are the some differences in the result of the questionnaires related to the efficacy between MJT test group and placebo group. The significant difference were observed in the CAMSOM-V at the 4th visit. Conclusion MJT is the safe and effective herbal prescription that is useful to the asthma patients.

Effect of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol on Immune Functions in Healthy Adults in a Randomized Controlled Trial

  • Hwang, Hee-Jin;Sohn, Ki-Young;Han, Yong-Hae;Chong, Saeho;Yoon, Sun Young;Kim, Young-Jun;Jeong, Jinseoun;Kim, Sang-Hwan;Kim, Jae Wha
    • IMMUNE NETWORK
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    • 제15권3호
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    • pp.150-160
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    • 2015
  • We previously reported that 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) accelerates hematopoiesis and has an improving effect on animal disease models such as sepsis and asthma. The effects of PLAG supplementation on immune modulation were assessed in healthy men and women. The objective was to evaluate the effects of PLAG supplementation on immune regulatory functions such as activities of immune cells and cytokine production. A randomized double blind placebo-controlled trial was conducted. Seventy-five participants were assigned to one of two groups; all participants had an appropriate number of white blood cells on the testing day. The PLAG group (n=27) received oral PLAG supplements and the control group (n=22) received oral soybean oil supplements. IL-4 and IL-6 production by peripheral blood mononuclear cells (PBMC) were lower (p<0.001 and p<0.001, respectively) with PLAG than with soybean oil. However, the production of IL-2 and IFN-$\gamma$ by PBMC was unaltered with PLAG supplementation. The B cell proliferation decreased significantly in the PLAG group compared to the soybean oil control (p<0.05). The intake of PLAG in healthy adults for 4 weeks was deemed safe. These data suggest that PLAG has an immunomodulatory function that inhibits the excessive immune activity of immunological disorders such as atopic and autoimmune diseases. PLAG could improve the condition of these diseases safely as a health food supplement.

Galerkin 해석법에 의한 원통 Panel의 진동 및 좌굴특성 (Vibration and Stability Characteristics of Cylindrical Panels by the Galerkin Method)

  • 박문호;박승진
    • 대한토목학회논문집
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    • 제11권4호
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    • pp.27-35
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    • 1991
  • 본 연구는 직선변이 단순지지, 원호변이 단순지지 및 고정지지 조건을 갖는 원통 panel을 해석하는 방법을 제시하였고 진동 및 좌굴에 관한 특성을 규명한 것이다. 초기응력을 받는 원통 panel을 지배하는 미분방정식은 Love-Timoshenko의 기초식을 이용하여 유도하였으며 이 미분방정식을 Galerkin 해석법을 이용하여 수치해석 하였다. 특히 고정 지지조건을 갖는 panel에 대해서는 시행함수로서 삼각함수로 구성되는 경우와 쌍곡선함수로 된 보의 고유함수로 구성되는 경우에 대하여 각각 해석하였으며 이들 시행함수가 수치해에 미치는 영향을 검토하였다. 수치해석의 결과로 곡률 parameter와 고유 진동수 및 임계 좌굴계수와의 관계를 검토하였다. 또한 진동 및 좌굴 모드를 도시하였다.

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당뇨병성 다발신경병증의 조기 진단에서 신경전도검사의 유용성에 관한 논란: 긍정적인 관점에서 (Controversies on the Usefulness of Nerve Conduction Study in the Early Diagnosis of Diabetic Polyneuropathy: Pros)

  • 권오현
    • Annals of Clinical Neurophysiology
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    • 제10권1호
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    • pp.29-32
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    • 2008
  • Although various criteria on the diagnosis of diabetic neuropathy are applied from trial to trial, being tailored in concert with its purpose, the utmost evidences of the diagnosis are subjective symptoms and objective signs of neurologic deficit. The application and interpretation of auxiliary electrophysiological test including nerve conduction study (NCS) should be made on the context of clinical pictures. The evaluation of the functions of small, thinly myelinated or unmyelinated nerve fibers has been increasingly stressed recently with the advent of newer techniques, e.g., measurement of intraepidermal fiber density, quantitative sensory testing, and autonomic function test. And the studies with those techniques have shed light to the nature of the evolution of diabetic neuropathy. The practical application of these techniques to the diagnosis of diabetic neuropathy in the individual patients, however, should be made cautiously due to several shortcomings: limited accessibility, wide overlapping zone between norm and abnormality with resultant unsatisfactory sensitivity and specificity, difficulty in performing subsequent tests, unproven quantitative correlation with clinical deficit, and invasiveness of some technique. NCS, as an extension of clinical examination, is still the most reliable electrophysiological test in evaluating neuropathy and gives the invaluable information about the nature of neuropathy, whereas the newer techniques need more refinement of the procedure and interpretation, and the accumulation of large scaled data of application to be considered as established diagnostic tools of peripheral neuropathy.

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