• 제목/요약/키워드: Multi factor Model

검색결과 573건 처리시간 0.028초

유리섬유쉬트에 의한 실물모형 RC보의 보강매수별 휨 보강효과 (Flexural Strengthening with Multi-Layer GFRP Sheets on Full-Scale RC Beams)

  • 유영찬;최기선;김긍환
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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    • pp.177-180
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    • 2005
  • The specified tensile strength provided by the manufacturer is determined on the basis of the reliable lower limit ($X-3{\sigma}$ : X=average tensile strength, $\sigma$=standard deviation) obtained from the material test results. Most of these data, however, are based on the test results of 1 layer of FRP sheet. Also, the partial strength reduction factor for strengthening RC members with FRP is based on the small-scale model tests. But, the failure mechanisms of small-scale model tests are reported to be different from those of the full-scale tests. This paper present the test results of full-scale RC beams strengthened with multi-layer GFRP sheets up to 3 layer as well as the material tests. From the material tests, it was observed that the average tensile strengths of GFRP sheets are decreased as the number of layer are increased. Also the premature debonding failure of RC beams strengthened with multi-layer GFRP sheets are observed in inverse proportion to the number of GFRP sheets

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망각 순환 최소자승을 이용한 다축 전지형 크레인의 적응형 모델 독립 제어 기반 조향제어 알고리즘 (Adaptive Model-Free-Control-based Steering-Control Algorithm for Multi-Axle All-Terrain Cranes using the Recursive Least Squares with Forgetting)

  • 오광석;서자호
    • 드라이브 ㆍ 컨트롤
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    • 제14권2호
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    • pp.16-22
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    • 2017
  • This paper presents the algorithm of an adaptive model-free-control-based steering control for multi-axle all-terrain cranes for which the recursive least squares with forgetting are applied. To optimally control the actual system in the real world, the linear or nonlinear mathematical model of the system should be given for the determination of the optimal control inputs; however, it is difficult to derive the mathematical model due to the actual system's complexity and nonlinearity. To address this problem, the proposed adaptive model-free controller is used to control the steering angle of a multi-axle crane. The proposed model-free control algorithm uses only the input and output signals of the system to determine the optimal inputs. The recursive least-squares algorithm identifies first-order systems. The uncertainty between the identified system and the actual system was estimated based on the disturbance observer. The proposed control algorithm was used for the steering control of a multi-axle crane, where only the steering input and the desired yaw rate were employed, to track the reference path. The controller and performance evaluations were constructed and conducted in the Matlab/Simulink environment. The evaluation results show that the proposed adaptive model-free-control-based steering-control algorithm produces a sound path-tracking performance.

Multi-FNN Identification Based on HCM Clustering and Evolutionary Fuzzy Granulation

  • Park, Ho-Sung;Oh, Sung-Kwun
    • International Journal of Control, Automation, and Systems
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    • 제1권2호
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    • pp.194-202
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    • 2003
  • In this paper, we introduce a category of Multi-FNN (Fuzzy-Neural Networks) models, analyze the underlying architectures and propose a comprehensive identification framework. The proposed Multi-FNNs dwell on a concept of fuzzy rule-based FNNs based on HCM clustering and evolutionary fuzzy granulation, and exploit linear inference being treated as a generic inference mechanism. By this nature, this FNN model is geared toward capturing relationships between information granules known as fuzzy sets. The form of the information granules themselves (in particular their distribution and a type of membership function) becomes an important design feature of the FNN model contributing to its structural as well as parametric optimization. The identification environment uses clustering techniques (Hard C - Means, HCM) and exploits genetic optimization as a vehicle of global optimization. The global optimization is augmented by more refined gradient-based learning mechanisms such as standard back-propagation. The HCM algorithm, whose role is to carry out preprocessing of the process data for system modeling, is utilized to determine the structure of Multi-FNNs. The detailed parameters of the Multi-FNN (such as apexes of membership functions, learning rates and momentum coefficients) are adjusted using genetic algorithms. An aggregate performance index with a weighting factor is proposed in order to achieve a sound balance between approximation and generalization (predictive) abilities of the model. To evaluate the performance of the proposed model, two numeric data sets are experimented with. One is the numerical data coming from a description of a certain nonlinear function and the other is NOx emission process data from a gas turbine power plant.

Cognitive Radio 무선 다중홉 릴레이 네트워크의 Throughput 용량 (Throughput Capacity of a Wireless Multi-hop Relay Network using Cognitive Radio)

  • ;송주빈;김영일
    • 대한전자공학회논문지TC
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    • 제44권5호
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    • pp.33-39
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    • 2007
  • 본 논문은 cognitive radio (CR) 기능을 갖는 무선 멀티홉 릴레이 네트워크의 throughput 용량에 대한 연구 결과이다. 본 논문에서는 TDMA/FDMA에 기반한 프레임 구조를 갖는 릴레이가 기지국과 통신할 때 CR 기술을 이용하여 현재 사용되고 있지 않는 주파수 자원을 측정하여 동적으로 이용하는 시스템을 제안하고 이의 throughput 용량 모델을 제안 하였다. 특히, 본 논문에서는 Utilization factor를 이용하여 제안된 시스템을 위한 throughput 용량 모델을 제안하였다. 해석 모델링 결과 본 논문에서 제안한 CR 기반 멀티홉 릴레이 시스템은 throughput 용량을 매우 향상하는 결과를 보였다.

Analysis of the Torque Characteristics of a Multi-Degrees of Freedom Surface Permanent-Magnet Motor

  • Kang, Dong-Woo;Go, Sung-Chul;Won, Sung-Hong;Lim, Seung-Bin;Lee, Ju
    • Journal of Magnetics
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    • 제15권1호
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    • pp.36-39
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    • 2010
  • The multi-degrees of freedom surface permanent-magnet motor (Multi-D.O.F. SPM) has several degrees of freedom operations that are defined as the "roll", "yaw", and "pitch". Normally, the torque that is generated to rotate a rotor includes ripples. The analysis of the torque ripples is important for improving motor performance. In terms of the electric analysis, torque ripple occurs as a result of many factors, including the rotor and stator structures, the distribution of the air-gap flux density, and the waveform of the current in the coils. In particular, the torque ripple is an important factor in the stable operation of the Multi-D.O.F. SPM. Therefore, in this work, the torque ripple was analyzed using various types of magnetization for the permanent magnet. An improved model was proposed for the Multi-D.O.F. SPM based on this analysis.

멀티도어코트하우스제도: 기원, 확장과 사례분석 (The Multi-door Courthouse: Origin, Extension, and Case Studies)

  • 정용균
    • 한국중재학회지:중재연구
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    • 제28권2호
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    • pp.3-43
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    • 2018
  • The emergence of a multi-door courthouse is related with a couple of reasons as follows: First, a multi-door courthouse was originally initiated by the United States government that increasingly became impatient with the pace and cost of protracted litigation clogging the courts. Second, dockets of courts are overcrowded with legal suits, making it difficult for judges to handle those legal suits in time and causing delays in responding to citizens' complaints. Third, litigation is not suitable for the disputant that has an ongoing relationship with the other party. In this case, even if winning is achieved in the short run, it may not be all that was hoped for in the long run. Fourth, international organizations such as the World Bank, UNDP, and Asia Development Bank urge to provide an increased access to women, residents, and the poor in local communities. The generic model of a multi-door courthouse consists of three stages: The first stage includes a center offering intake services, along with an array of dispute resolution services under one roof. At the second stage, the screening unit at the center would diagnose citizen disputes, then refer the disputants to the appropriate door for handling the case. At the third stage, the multi-door courthouse provides diverse kinds of dispute resolution programs such as mediation, arbitration, mediation-arbitration (med-arb), litigation, and early neutral evaluation. This study suggests the extended model of multi-door courthouse comprised of five layers: intake process, diagnosis and door-selection process, neutral-selection process, implementation process of dispute resolution, and process of training and education. One of the major characteristics of extended multi-door courthouse model is the detailed specification of individual department corresponding to each process within a multi-door courthouse. The intake department takes care of the intake process. The screening department plays the role of screening disputes, diagnosing the nature of disputes, and determining a suitable door to handle disputes. The human resources department manages experts through the construction and management of the data base of mediators, arbitrators, and judges. The administration bureau manages the implementation of each process of dispute resolution. The education and training department builds long-term planning to procure neutrals and experts dealing with various kinds of disputes within a multi-door courthouse. For this purpose, it is necessary to establish networks among courts, law schools, and associations of scholars in order to facilitate the supply of manpower in ADR neutrals, as well as judges in the long run. This study also provides six case studies of multi-door courthouses across continents in order to grasp the worldwide picture and wide spread phenomena of multi-door courthouse. For this purpose, the United States and Latin American countries including Argentina and Brazil, Middle Eastern countries, and Southeast Asian countries (such as Malaysia and Myanmar), Australia, and Nigeria were chosen. It was found that three kinds of patterns are discernible during the evolution of a multi-door courthouse model. First, the federal courts of the United States, land and environment court in Australia, and Lagos multi-door courthouse in Nigeria may maintain the prototype of a multi-door courthouse model. Second, the judicial systems in Latin American countries tend to show heterogenous patterns in terms of the adaptation of a multi-door courthouse model to their own environments. Some court systems of Latin American countries including those of Argentina and Brazil resemble the generic model of a multi-door courthouse, while other countries show their distinctive pattern of judicial system and ADR systems. Third, it was found that legal pluralism is prevalent in Middle Eastern countries and Southeast Asian countries. For example, Middle Eastern countries such as Saudi Arabia have developed various kinds of dispute resolution methods, such as sulh (mediation), tahkim (arbitration), and med-arb for many centuries, since they have been situated at the state of tribe or clan instead of nation. Accordingly, they have no unified code within the territory. In case of Southeast Asian countries such as Myanmar and Malaysia, they have preserved a strong tradition of customary laws such as Dhammthat in Burma, and Shriah and the Islamic law in Malaysia for a long time. On the other hand, they incorporated a common law system into a secular judicial system in Myanmar and Malaysia during the colonial period. Finally, this article proposes a couple of factors to strengthen or weaken a multi-door courthouse model. The first factor to strengthen a multi-door courthouse model is the maintenance of flexibility and core value of alternative dispute resolution. We also find that fund raising is important to build and maintain the multi-door courthouse model, reflecting the fact that there has been a competition surrounding the allocation of funds within the judicial system.

영아 놀이성 척도의 개발 및 타당화 연구 (The Development and Validation of a Playfulness Scale for Infants & Toddlers)

  • 김연숙;이종희
    • 아동학회지
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    • 제33권6호
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    • pp.85-107
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    • 2012
  • In this study, the Infants & Toddlers' Playfulness Scale(ITPS) was developed and its reliability and validity were examined. The participants in this study consisted of 656 parents whose children were 8 to 36 months old. Five factors were identified from the results of the exploratory factor analysis performed on the 29 items that had been derived by analyzing existing research. The Goodness of Fit Indices(GFIs) of the confirmatory factor analyses, performed on the 1st-order 5-factor model and the 2nd-order one factor model, were both satisfactory. Concurrent validity was established by the high correlations of r = .631~.808(p < .01) between each factor of the ITPS and the total score of the Children's Playfulness Scale(CPS), an existing measure for children's playfulness. The reliability of each factor, as measured by Cronbach's ${\alpha}$, ranged from .773 to .883. Consequently, the ITPS developed in this study can be seen as a reliable and valid scale that can be used by parents to measure the playfulness of their infants and toddlers in a multi-dimensional manner.

콘크리트의 방향적 비국소 균열 손상을 위한 소성모델 (Plasticity Model for Directional Nonlocal Crack Damage of Concrete)

  • 김재요;박홍근
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2006년도 정기 학술대회 논문집
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    • pp.914-921
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    • 2006
  • To describe the effect of the numerous and various oriented microcracks on the compressive and tensile concrete behaviors, the directional nonlocality is defined. The plasticity model using multiple failure criteria is developed for RC planar members in tension-compression. The crack damages are defined in the pre-determined reference orientations, and then the total crack damage is calculated by integrating multi-oriented crack damages. To describe the effect of directional nonlocality on the anisotropic tensile damage, based on the existing test results, the nonlocal damage factor is defined in each reference orientation. The reduced compressive strength in the cracked concrete is defined by the multi-oriented crack damages defined as excluding the tensile normal plastic strain from the compressive equivalent plastic strain. The proposed model is implemented to finite element analysis, and it is verified by comparisons with various existing panel test results.

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Stochastic response spectra for an actively-controlled structure

  • Mochio, Takashi
    • Structural Engineering and Mechanics
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    • 제32권1호
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    • pp.179-191
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    • 2009
  • A stochastic response spectrum method is proposed for simple evaluation of the structural response of an actively controlled aseismic structure. The response spectrum is constructed assuming a linear structure with an active mass damper (AMD) system, and an earthquake wave model given by the product of a non-stationary envelope function and a stationary Gaussian random process with Kanai-Tajimi power spectral density. The control design is executed using a linear quadratic Gaussian control strategy for an enlarged state space system, and the response amplification factor is given by the combination of the obtained statistical response values and extreme value theory. The response spectrum thus produced can be used for simple dynamical analyses. The response factors obtained by this method for a multi-degree-of-freedom structure are shown to be comparable with those determined by numerical simulations, demonstrating the validity and utility of the proposed technique as a simple design tool. This method is expected to be useful for engineers in the initial design stage for structures with active aseismic control.

수증기-메탄개질용 Ni 촉매의 유용도에 관한 수치적 연구 (A Numerical Study on the Effectiveness Factor of Ni Catalyst Pellets for Steam-Methane Reforming)

  • 최종균;남진현;신동훈;정태용;김영규
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.63-66
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    • 2007
  • Reformers which produce hydrogen from natural gas are essential for the operation of residential PEM fuel cells. For this purpose, steam-methane reforming reactions with Ni catalysts is primarily utilized. Commercial Ni catalysts are generally made to have porous pellet shapes in which Ni catalyst particles are uniformly dispersed over Alumina support structures. This study numerically investigates the reduction of catalyst effectiveness due to the mass transport resistances posed by porous structures of spherical catalyst pellets. The multi-component diffusion through porous media and the accurate kinetics of reforming reaction is fully considered in the numerical model. The preliminary results on the variation of the effectiveness factor according to different operation conditions are presented, which is planned to be used to develop correlations in future studies.

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