• Title/Summary/Keyword: Gradients

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Numerical analysis of thermal and composite stresses in pre-stressed concrete pavements

  • Nejad, Fereidoon Moghadas;Ghafari, Sepehr;Afandizadeh, Shahriar
    • Computers and Concrete
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    • v.11 no.2
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    • pp.169-182
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    • 2013
  • One of the major benefits of the pre-stressed concrete pavements is the omission of tension in concrete that results in a reduction of cracks in the concrete slabs. Therefore, the life of the pavement is increased as the thickness of the slabs is reduced. One of the most important issues in dealing with the prestressed concrete pavement is determination of the magnitude of the pre-stress. Three dimensional finite element analyses are conducted in this research to study the pre-stress under various load (Boeing 777) and thermal gradient combinations. The model was also analyzed under temperature gradients without the presence of traffic loading and the induced stresses were compared with those from theoretical relationships. It was seen that the theoretical relationships result in conservative values for the stress.

Numerical Studies on Submerged Arc Welding Process

  • Kiran, Degala Ventaka;Na, Suck-Joo
    • Journal of Welding and Joining
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    • v.32 no.4
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    • pp.1-9
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    • 2014
  • A quantitative understanding on the effect of the welding conditions on weld joint dimensions and weld thermal cycle is difficult through experimental studies alone. The experimental realization of temperature distribution in the weld pool is proved to be extremely difficult due to the small size of welds, high peak temperature and steep temperature gradients in weld pool. This review deals with the heat transfer and fluid flow analysis to understand the parametric influence of a single wire submerged arc welding (SAW) and multi-wire SAW processes on the weld bead dimensions, temperature and fluid flow distribution in the weldment.

Coupled temperature-displacement modeling to study the thermo-elastic instability in disc brakes

  • Ramkumar, E.;Mayuram, M.M.
    • Coupled systems mechanics
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    • v.1 no.2
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    • pp.165-182
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    • 2012
  • Macroscopic hot spots formed due to the large thermal gradients at the surface of the disc brake rotor, make the rotor to fail or wear out early. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature making the disc susceptible to hot spot formation. The formation of one hot spot event will predispose the system to future hot spotting at the same location. This leads to the complete thermo-elastic instability in the disc brakes; multitude parameters are responsible for the thermo elastic instability. The predominant factor is the sliding velocity and above a certain sliding velocity the instability of the brake system occurs and hot spots is formed in the surface of the disc brake. Commercial finite element package ABAQUS(R) is used to find the temperature distribution and the result is validated using Rowson's analytical model. A coupled analysis methodology is evolved for the automotive disc brake from the transient thermo-elastic contact analysis. Temperature variation is studied under different sliding speeds within the operation range.

People Detection based HOG-LBP using Various Gamma Correction (다양한 Gamma 보정을 이용한 HOG-LBP 기반 사람검출)

  • Ko, Jung-Sob;Lee, Chul-Hee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.05a
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    • pp.639-641
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    • 2012
  • People detection using HOG linear SVM classification has been successfully applied. Also, HOG combined with LBP, which reflects texture informations, shows improved performance. In this paper, we analyze various gamma correction methods. We also analyze results obtained using HOG+LBP methods.

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Numerical Study on Turbulent Flow and Heat Transfer in the Rocket Nozzle (로켓 노즐 내의 난류유동 및 열 전달에 관한 수치 해석적 연구)

  • 배주찬;이태호;강신형
    • Journal of the Korean Society of Propulsion Engineers
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    • v.1 no.1
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    • pp.73-81
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    • 1997
  • Numerical analysis on turbulent flow and heat transfer in the rocket nozzle has been studied using the mass-weighted-averaged full Navier-Stokes equations, the Morkovin hypothesis on turbulent flow, the $\textsc{k}$-$\varepsilon$ turbulence model with the wall function specially designed to be able to consider the effects of pressure gradients, heat transfer and compressibility, and the numerical scheme of Karki. The present results are in good agreement with the experiments of Back et al.

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Effects of Nutritional State on Physiological Responses and Heat Production During Exercise of the Animal - a Review

  • Kasa, I Wayan
    • Asian-Australasian Journal of Animal Sciences
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    • v.11 no.4
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    • pp.331-336
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    • 1998
  • This review was conducted to analyse the effect of nutrition on physiological responses; heat production of domestic animal during exercise. Overall, it can be concluded that the major factors likely to affect heat production in domestic animals during exercise (including work load) are body weight, speed, the gradients attempted, feed intake, ambient conditions (including temperature and solar radiation) and altitude. On nutrition-exercise interactions, for example, it has been concluded that animals on better quality diets produce more heat than those on poorer quality ones, and that glucose as well as acetate are metabolized as energy sources during both rest and exercise.

Prediction of plasma etching using genetic-algorithm controlled backpropagation neural network

  • Kim, Sung-Mo;Kim, Byung-Whan
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1305-1308
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    • 2003
  • A new technique is presented to construct a predictive model of plasma etch process. This was accomplished by combining a backpropagation neural network (BPNN) and a genetic algorithm (GA). The predictive model constructed in this way is referred to as a GA-BPNN. The GA played a role of controlling training factors simultaneously. The training factors to be optimized are the hidden neuron, training tolerance, initial weight magnitude, and two gradients of bipolar sigmoid and linear functions. Each etch response was optimized separately. The proposed scheme was evaluated with a set of experimental plasma etch data. The etch process was characterized by a $2^3$ full factorial experiment. The etch responses modeled are aluminum (A1) etch rate, silica profile angle, A1 selectivity, and dc bias. Additional test data were prepared to evaluate model appropriateness. The GA-BPNN was compared to a conventional BPNN. Compared to the BPNN, the GA-BPNN demonstrated an improvement of more than 20% for all etch responses. The improvement was significant in the case of A1 etch rate.

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Methods of Design Optimality Evaluation for Caisson Structural Systems (케이슨 구조계의 설계 최적성 평가)

  • Choi Min-Hee;Ryu Yeon-Sun;Cho Hyun-Man;Na Won-Bae
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.89-96
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    • 2005
  • Numerical procedure of design optimality evaluation is studied for caisson structural systems. Two kinds of evaluation methods can be considered; mathematical optimality criteria method (MOCM) and numerical optimization method (NOM). The choice of the method depends on the available information of the system MOCM can be used only when the information of all function values, gradients and Lagrange multipliers is available, which may not be realistic in practice. Therefore, in this study, NOMs are applied for the structural optimality evaluation, where only design variables are necessary. To this end, Metropolis genetic algorithm (MGA) is advantageously used and applied for a standard optimization model of caisson composite breakwater. In the numerical example, cost and constraint functions are assumed to be changed from the orignal design situation and their effects are evaluated for optimality. From the theoretical consideration and numerical experience, it is found that the proposed optimality evaluation procedure with MGA-based NOM is efficient and practically applicable.

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HOG-HOD Algorithm for Recognition of Multi-cultural Hand Gestures (다문화 손동작 인식을 위한 HOG-HOD 알고리즘)

  • Kim, Jiye;Park, Jong-Il
    • Journal of Korea Multimedia Society
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    • v.20 no.8
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    • pp.1187-1199
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    • 2017
  • In recent years, research about Natural User Interface (NUI) has become focused because NUI system can give natural feelings for users in virtual reality. Most important thing in NUI system is how to communicate with the computer system. There are many things to interact with users such as speech, hand gestures, body actions. Among them, hand gesture is suitable for the purpose of NUI because people often use a relatively high frequency in daily life and hand gesture have meaning only by itself. This hand gestures called multi-cultural hand gesture and we proposed the method to recognize this kind of hand gestures. Proposed method is composed of Histogram of Oriented Gradients (HOG) used for hand shape recognition and Histogram of Oriented Displacements (HOD) used for hand center point trajectory recognition.

New Thermal-Aware Voltage Island Formation for 3D Many-Core Processors

  • Hong, Hyejeong;Lim, Jaeil;Lim, Hyunyul;Kang, Sungho
    • ETRI Journal
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    • v.37 no.1
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    • pp.118-127
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    • 2015
  • The power consumption of 3D many-core processors can be reduced, and the power delivery of such processors can be improved by introducing voltage island (VI) design using on-chip voltage regulators. With the dramatic growth in the number of cores that are integrated in a processor, however, it is infeasible to adopt per-core VI design. We propose a 3D many-core processor architecture that consists of multiple voltage clusters, where each has a set of cores that share an on-chip voltage regulator. Based on the architecture, the steady state temperature is analyzed so that the thermal characteristic of each voltage cluster is known. In the voltage scaling and task scheduling stages, the thermal characteristics and communication between cores is considered. The consideration of the thermal characteristics enables the proposed VI formation to reduce the total energy consumption, peak temperature, and temperature gradients in 3D many-core processors.