• Title/Summary/Keyword: Variable Structure Systems

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Nonhomogeneous atherosclerotic plaque analysis via enhanced 1D structural models

  • Varello, Alberto;Carrera, Erasmo
    • Smart Structures and Systems
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    • v.13 no.4
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    • pp.659-683
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    • 2014
  • The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.

The Multimedia Service Scheduling method applying AMC based on Cross Layer technique for Mobile Communication Systems (이동통신 시스템을 위한 크로스레이어 기반의 AMC를 적용한 멀티미디어 서비스 스케줄링 기법)

  • Kim, Kyung-Seok;Kim, Joo-Seok
    • Journal of Korea Multimedia Society
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    • v.11 no.9
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    • pp.1238-1244
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    • 2008
  • Each layer operates independently in the present network structure. However, the importance of designing cross layer, which adapt between different layers, is on the rise, because of adapt to the variable communication environments. In this paper, we investigate the scheduling techniques of the cross layer. we research conventional scheduling methods and propose the multimedia service scheduling method which will be applied in future wireless communication environments. This method considers the diversity of multimedia service and manages the radio resources efficiently Moreover, we apply AMC for flexibility and improve the performance of the scheduling method. The proposed method is verified through the simulation appying variable environments.

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A Study on Dynamic Message Processing for KVMF Messages based on KVID (KVID기반 KVMF메시지의 동적 메시지 처리 연구)

  • Cho, Chul-Young;Lee, Jun-Pyo;Kwon, Cheol-Hee;Cho, Han-Jun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.2C
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    • pp.173-180
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    • 2012
  • It is important to consider saving location of message structures, structure of parser and creating method of parser generator for adopting KVMF to increase interoperability among different weapon systems. Especially, it requires to design the message parser by analyzing performance and maintenance when we adopting KVMF to previously developed weapon systems. In this paper, we propose the method of concurrent dynamic message processing for KMVF message based on KVID to support the developed and next-developed weapon systems. We show message conversion accuracy and performance effectiveness by adopting proposed method to Batallion Tactical Combat System.

Desist of Robust Output Feedback Variable Structure Control Systems (강인한 출력궤환 가면구조제어계의 설계)

  • Lee, Kee-Sang;Lim, Jae-Hyung;Lee, Jung-Dong
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.433-435
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    • 1993
  • The purpose of this study is to propose a robust OFVSCS that have the robust properties against process parameter variations and external disturbances by extending the basic OFVSCS and to evaluate its control performances. The ROFVSCS is composed of dynamic switching surfaces and output feedback switching control inputs that are constructed by the use of the unknown vector modeling technique. With the proposed scheme. existence of sliding mode is guaranteed and any nonzero bias can be suppressed in the face of disturbances and process parameter variations as far as well-known matching condition is satisfied. Due to the fact that the ROFVSCS is driven by small number of measured information, the practical application of VSCS for the systems with unmeasurable states and for high order systems. that conventional schemes cannot be applied, is possible with the proposed scheme. It is noticeable that implementation cost or VSCS can be considerably reduced without sacrifice of control performances by adopting ROFVSCS since there is no need to measure the states with high measurement cost.

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The Hybrid Multi-layer Inference Architectures and Algorithms of FPNN Based on FNN and PNN (FNN 및 PNN에 기초한 FPNN의 합성 다층 추론 구조와 알고리즘)

  • Park, Byeong-Jun;O, Seong-Gwon;Kim, Hyeon-Gi
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.7
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    • pp.378-388
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    • 2000
  • In this paper, we propose Fuzzy Polynomial Neural Networks(FPNN) based on Polynomial Neural Networks(PNN) and Fuzzy Neural Networks(FNN) for model identification of complex and nonlinear systems. The proposed FPNN is generated from the mutually combined structure of both FNN and PNN. The one and the other are considered as the premise part and consequence part of FPNN structure respectively. As the consequence part of FPNN, PNN is based on Group Method of Data Handling(GMDH) method and its structure is similar to Neural Networks. But the structure of PNN is not fixed like in conventional Neural Networks and self-organizing networks that can be generated. FPNN is available effectively for multi-input variables and high-order polynomial according to the combination of FNN with PNN. Accordingly it is possible to consider the nonlinearity characteristics of process and to get better output performance with superb predictive ability. As the premise part of FPNN, FNN uses both the simplified fuzzy inference as fuzzy inference method and error back-propagation algorithm as learning rule. The parameters such as parameters of membership functions, learning rates and momentum coefficients are adjusted using genetic algorithms. And we use two kinds of FNN structure according to the division method of fuzzy space of input variables. One is basic FNN structure and uses fuzzy input space divided by each separated input variable, the other is modified FNN structure and uses fuzzy input space divided by mutually combined input variables. In order to evaluate the performance of proposed models, we use the nonlinear function and traffic route choice process. The results show that the proposed FPNN can produce the model with higher accuracy and more robustness than any other method presented previously. And also performance index related to the approximation and prediction capabilities of model is evaluated and discussed.

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An Empirical Study on the Fitness between Manufacturing Technology Strategy and product Structure - Based on Korean Electric and Electronic Industry - (제품구조와 생산기술간의 적합성에 관한 실증적 연구 - 우리나라 전기 . 전자산업을 중심으로 -)

  • 이경환;임재화
    • Proceedings of the Technology Innovation Conference
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    • 1992.12a
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    • pp.119-155
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    • 1992
  • Traditionally, the target of manufaturing technology strategy was derived in a efficiency, cost and productivity. So most activities of the manufacturing brought focus into the engineering technology, equipments and research and improvement of new products to maximize the efficiency. As a resell of this legacy, most of the activities of manufacturing has been executed on the method of quality improvement, development of new equipment to incense the efficiency and the research of materials for new products. Those trends, however overlook the operation management activities which is very important as a assets in competitive strategy. But the market enviornment of morden manufacturing companies faced to the uncertainty and complexity. So they need capability of competition which requires new concept of manufacturing technology strategy to grasp the competitive advantages. In this point of view, this paper deal with the empirical study in korean manufacturing technology strategy of the electic and electronic industry. For the empirical study, check list was made to survey the 98 manufacturing companies. The analysis procedures are as below. First, identify the manufacturing technology group an product structure group by each variable. Second manufacturing technology variables are segmented into product technology and vertical integration, suborder and infrastructure, to analyse the decision making pattern which derive the strategy groups. Third, by the fitness analysis between product structure group and manufacturing technology group, the economic results of a growth rate of sale and a profit rate of sale are tested. In this approach, fitness analysis between product structure group and manufacturing technology group show, as a whole, the no significant values in economic results of the company. But investigating the statistical values shows the trend that econmic result of the complany is somewhat higher when the degree of fitness of manufacturing technology strategy by product structure has high value. Concluding the remarks, the competitive advantages of company lies not in the efficiency of manufacturing systems but in the way of the structure and decision making pattern of the manufacturing system. And the cons i stoney between strategy target and manufacturing technology strategy, and the consistency of manufacturing technology strategy and product structure are the term of competitive advantages.

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Method that determining the Hyperparameter of CNN using HS algorithm (HS 알고리즘을 이용한 CNN의 Hyperparameter 결정 기법)

  • Lee, Woo-Young;Ko, Kwang-Eun;Geem, Zong-Woo;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.27 no.1
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    • pp.22-28
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    • 2017
  • The Convolutional Neural Network(CNN) can be divided into two stages: feature extraction and classification. The hyperparameters such as kernel size, number of channels, and stride in the feature extraction step affect the overall performance of CNN as well as determining the structure of CNN. In this paper, we propose a method to optimize the hyperparameter in CNN feature extraction stage using Parameter-Setting-Free Harmony Search (PSF-HS) algorithm. After setting the overall structure of CNN, hyperparameter was set as a variable and the hyperparameter was optimized by applying PSF-HS algorithm. The simulation was conducted using MATLAB, and CNN learned and tested using mnist data. We update the parameters for a total of 500 times, and it is confirmed that the structure with the highest accuracy among the CNN structures obtained by the proposed method classifies the mnist data with an accuracy of 99.28%.

The Characteristics of Flexibility applied to Unit Plan of Housing by Residents Participation - focusing on European Multi-story Housing applying Residents Participation - (거주자 참여형 공동주거의 평면계획에 적용된 가변성의 특성 - 유럽의 거주자 참여형 다층 공동주거를 중심으로 -)

  • Kim, Hyun-Ju
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.11
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    • pp.113-123
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    • 2018
  • First of all, the multi-story Housing applying resident's participation in europe was classified by the menu selection method, the two-step supply method and the cooperative method. And then I analyzed flexible unit plan of cases for deriving the planning methode and the characteristics of flexibility. First, I analyzed the area and form of the unit plan, structure and Installation, fixed and variable elements to derive the planning method. The area of units are distributed from a minimum of $35m^2$ to a maximum of $150m^2$, and many of the unit planes have a narrow front and a deep depth. The structure is a long-span wall-structure or a skeleton structure, and is designed without any columns and bearing walls in the interior space for flexibility in spatial composition. The vertical shafts are located in the center of the unit in a box-form or in the corner at the unit dividing wall for free placement of interior wall. Fixed elements are framework and facility systems. Most of the future residents in the two-steps supply method and the cooperative method were able to freely design the internal space within the zoning concept proposed by the architect and change the location of the facade element within module system proposed by the architect. Second, the characteristics of the flexibility applied to the unit plan were divided in integrated flexibility, functional flexibility, construction flexibility, and supply flexibility. The integrated flexibility enables residents to give the variable space combination based on the complex structure of the inner space for providing various living experiences. Regarding functional flexibility, the three-dimensional spatial structure with neutral space has multi-functionality according to the needs of residents and easily accepts mixing of hybrid programs such as work and residence. Constructive flexibility allows residents to create identity by freely planning interior space and changing the size or location of facade components in a determined system of architects. Finally, various types of size and space composition are proposed and realized in the whole building applying menu selection method, so that flexibility in the offer can accommodate and integrate various types of living.

A New Robust Continuos VSCS by Saturation Function for Uncertain Nonlinear Plants (불확실 비선형 플랜트를 위한 포화 함수에 의한 새로운 강인한 연속 가변구조제어시스템)

  • Lee, Jung-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.48 no.3
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    • pp.30-39
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    • 2011
  • In this note, a systematic design of a new robust nonlinear continuous variable structure control system(VSCS) based on the modified state dependent nonlinear form is presented for the control of uncertain affine nonlinear systems with mismatched uncertainties and matched disturbance. After an affine uncertain nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a new robust nonlinear VSCS is presented. The uncertainty of the nonlinear system function is separated into the tow parts, i.e., state dependent term and state independent term for extension of target plants. To be linear in the closed loop resultant dynamics and in order to easily satisfy the existence condition of the sliding mode, the transformed linear sliding surface is applied. A corresponding control input is proposed to satisfy the closed loop exponential stability and the existence condition of the sliding mode on the linear transformed sliding surface, which will be investigated in Theorem 1. For practical application, the discontinuity of the control input as the inherent property of the VSS is improved dramatically. Through a design example and simulation studies, the usefulness of the proposed controller is verified.

A Study on the Design Plan of Naval Combat System Software to Reduce Cost of Hardware Discontinuation Replacement

  • Jeong-Woo, Son
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.1
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    • pp.71-78
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    • 2023
  • In this paper, we analyze the structure of TV video software, one of the warship combat management system software, and propose a standard architecture that minimizes software modification due to the discontinuation replacement of warship hardware. The class structure was newly designed to minimize the class modified when replacing the warship hardware by separating the variable elements and common elements of TV video software through FORM(Feature-Oriented Reuse Method), the common part that communicates with the warship combat management system and displays the TV screen and the variable part that communicates between the operator and the TV camera. In addition, the Strategy design pattern is applied to efficiently add and modify classes that directly use hardware-dependent APIs when replacing hardware discontinuation, and to make both discontinued and replacements available software. Finally, the reliability testing time and functional testing time of the existing TV video software and the proposed software were measured and compared, and finally, it was confirmed that the hardware discontinuation replacement cost was reduced.