• Title/Summary/Keyword: Problem Space

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Output-error state-space identification of vibrating structures using evolution strategies: a benchmark study

  • Dertimanis, Vasilis K.
    • Smart Structures and Systems
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    • v.14 no.1
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    • pp.17-37
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    • 2014
  • In this study, four widely accepted and used variants of Evolution Strategies (ES) are adapted and applied to the output-error state-space identification problem. The selection of ES is justified by prior strong indication of superior performance to similar problems, over alternatives like Genetic Algorithms (GA) or Evolutionary Programming (EP). The ES variants that are being tested are (i) the (1+1)-ES, (ii) the $({\mu}/{\rho}+{\lambda})-{\sigma}$-SA-ES, (iii) the $({\mu}_I,{\lambda})-{\sigma}$-SA-ES, and (iv) the (${\mu}_w,{\lambda}$)-CMA-ES. The study is based on a six-degree-of-freedom (DOF) structural model of a shear building that is characterized by light damping (up to 5%). The envisaged analysis is taking place through Monte Carlo experiments under two different excitation types (stationary / non-stationary) and the applied ES are assessed in terms of (i) accurate modal parameters extraction, (ii) statistical consistency, (iii) performance under noise-corrupted data, and (iv) performance under non-stationary data. The results of this suggest that ES are indeed competitive alternatives in the non-linear state-space estimation problem and deserve further attention.

An In-depth Study on Applying Metric Weighting to Space Syntax (공간구문론에의 거리가중개념 적용에 관한 심층 연구)

  • Kim, Minseok;Piao, Gensong
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.12
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    • pp.49-54
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    • 2018
  • Applying metric(distance) factor as weighting to spatial syntax is known to not contribute to the explanatory power for the human movement behavior as compared to the geometric(angle) factor according to the negative results of several related studies. However, Kim & Piao (2017) assumed that there is not a problem of the metric factor itself but a problem of the way of applying the metric factor as weighting, and presented a new possibility of the metric factor as weighting by proposing and verifying the methods of applying the metric weighting, which are different from the existing ones. The purpose of this study is to propose advanced methods of applying the metric weighting to space syntax, and to verify whether they contribute to the improvement of explanatory power of space syntax analysis. In this paper, we propose functions for combined depth of distance-step that combine the distance-weighted depth function with the step depth function and apply them to axial segment analysis to check the improvement of explanatory power of them.

A Study of Utilization of Semi-public Space of Street for the Betterment in Life Environment (도시생활환경 개선을 위한 도로변 공개공지의 활용실태에 관한 연구)

  • 김한수;정준현
    • Journal of the Korean housing association
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    • v.11 no.2
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    • pp.85-95
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    • 2000
  • This study tries to promote an effective use of semi-public space of urban street in social point of view. The main results are follows. First, semi-public space is occupied by private users and it makes urban landscape unrecoverable. The real problem is that people do not know the space is for public use rather than pure private use. Second, the standard of semi-public space requirement should be changed from floor space to lot area. In addition, the standard should apply to buildings on an area less than a legal standard. Third, some ways of attaining the semi-public space in relation with adjacent lots should be introduced in the case of urban redevelopment nad living condition improvement projects.

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PREPROXIMITY, UNIFORMITY SPACES AND APPLICATIONS OF (E, L) FUZZIFYING MATROID

  • Khalaf, Mohammed M.
    • Honam Mathematical Journal
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    • v.40 no.1
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    • pp.27-46
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    • 2018
  • In this paper, (E, L)-preproximity and uniformity spaces in matriod theory as a generalized to a classical proximity and Uniformity spaces introduced by Csaszar [1] is introduced. Recently, Shi [17]-[18] introduced a new approach to the fuzzification of matroids.Here introduce (E, L)-preproximity and uniformity spaces, Uniformity and strong uniformity on (E, L)-fuzzifying matroid space, Not only study the properties of this new notions, but it has been generated (E, L)-fuzzifying matroid Space from (E, L)-preproximity and uniformity spaces. Next to introduced (E, L)-preproximity continuous in (E, L)-fuzzifying matroid space and used it in more properties. Finally we solve combinatorial optimizations problem via (E, L)-fuzzifying matroid space.

Topology Optimization for a Knuckle Using Design Space Adjustment and Refinement (설계공간 조정과 세분화를 이용한 너클의 위상 최적설계)

  • Yu Yong-Gyun;Kwak Byung-Man;Jang In-Gwun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.5 s.248
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    • pp.595-601
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    • 2006
  • Design space optimization using design space adjustment and refinement is used to optimize a knuckle in the suspension system of an automobile. This approach is a new efficient method for large-scale topology optimization by virtue of two reasons. First, design space adjustment including design space expansion and reduction is suitable for large-scale problems. Second, the design space refinement can be done globally or locally where and when necessary and thus is very effective in obtaining a target resolution with much less number of elements. Compliance minimization for a knuckle is considered with a realistic working condition to show the effectiveness and superiority of the new approach.

Evaluation of Creative Space Efficiency in China' Provinces Based on AHP Method

  • Hu, Shan-Shan;Kim, Hyung-Ho
    • International journal of advanced smart convergence
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    • v.9 no.4
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    • pp.52-61
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    • 2020
  • The AHP method was used in 30 provinces of China to construct the index system of creative space efficiency evaluation and determine the weight of each index. The fuzzy comprehensive evaluation method was further used to score the indexes at all levels, and then the total efficiency score was sorted. The purpose of this study is to adjust the regional layout of creative space reasonably and implement financial policies accurately through the evaluation of the efficiency of creative space. The results is ranking top in weight of several indicators, which include the number of incubated Startups, the number of innovation and entrepreneurship mentors, the survival rate of incubator, the innovative training activities, etc. It was also found that Beijing, Shanghai, Jiangsu, Guangdong and Zhejiang ranked first in the score of creative space efficiency. This study is meaningful in that it was In order to effectively solve the problem of the imbalance of the creative space efficiency in China's province, by coordinating the regional pattern, establishing a sound service system and improving the efficiency evaluation system.

A Study on the increase of space debris from Chinese Anti-Satellite and breach of the Outer Space Treaty (자국위성(自國衛星)의 파괴(破壞)에 따른 우주잔해의 증가와 우주조약위반(宇宙條約違反) 여부에 관한 소고(小考) - 중국의 자국위성파괴와 관련하여 -)

  • Kim, Sun-Ihee
    • The Korean Journal of Air & Space Law and Policy
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    • v.28 no.2
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    • pp.259-294
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    • 2013
  • After its experiment involving the exploding of a satellite in space in 2007, China proudly aired news on TV and ran articles in newspapers. However, the event was internationally criticized and drew widespread attention. Many countries denounced the explosion by pointing out that it could be part of the nation's plan to expand its military power to space or that it could pose a danger to the peaceful use of space. However, there is no talk of whether the experiment that produced a huge amount of space debris could have violated an international law, namely the Outer Space Treaty. Although space garbage has been said to be a serious problem, the amount is still on the increase. If we continue to launch new space launch vehicles into orbit at this rate, we will not be able to use it anytime soon like we do today. As the commercial use of space is likely to increase, the situation will certainly get worse. The international community is fully aware of the seriousness of the problem and working together to reduce the amount of space garbage. However, despite the fact that the United States and Soviet Union's ASAT(Anti-Satellite) programs have been implemented for a long time, there have been no complaints about them in terms of military expansion or breach of the Outer Space Treaty. Also, the recent Chinese test is largely viewed to be in accordance with international law. A lot of research has been undertaken with regard to the problem of space garbage. Now people's awareness of dangers being posed has been fully raised. Under the circumstances, the dismissing of China's satellite smashing, leaving a big mess in its wake, as nothing more than an experiment, is a red flag to, if not many, at least some people. By means of this thesis, I would like to review whether the Chinese test has violated an international space law. This thesis presents an overview of the issues surrounding the event and examines the possibility of violating the Outer Space Treaty, formally the Treaty on Principle Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies. After the China test, the UN Scientific and Technical Subcommittee first adopted space debris mitigation guidelines, I'll introduce the content of the guidelines and discuss the characteristics of the guidelines and what can be done to address the issue.

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A Study on the Charactertics of Ecological Architectural Space of Frei Otto (프라이 오토(Frei Otto)의 건축에 나타난 생태학적 공간특성에 관한 연구)

  • 최경실
    • Korean Institute of Interior Design Journal
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    • no.11
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    • pp.45-56
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    • 1997
  • In the process of modermization the problem of environment destruction has become a worldwide issue. And now this problem is a concern for all branches of science, including that of architectural desigv. This thesis tries to find the meaning of ecological architectural space, one that encreases the organic relationship, and communication, between architectrual space and urban environmental space, between human beings and architecture, and between human beings and their environment. As an example, we will take a look at the architectural space-design of Frei Otto, who offers diverse creative ecological architectural forms. His concept of architecture has the critical character when compared with the traditionan conventional concept of architecture. The ecological characteristics of his architectural spacedesign can be summarized as follows: The first characteristic is his ample use of natural objects in the architectural structure. An ample use of living things like trees and plants as well as of inanimate thing like water, wind as architectural elements enhances the functional efficiency of architecture. The second characteristic is its ecological architectural system, which saves energy faciliates ventilation by changing the position and direction of the building, by systematically applying the materials, and by efficiently arranging the inner space. The third characteristic is the dematerialization of architecture and the use of materials that are economical and appropriate for the circulation system of nature. The use of natural elements and recycling natural objects, makes it possible to reuse materials of the destroyed building. In short, the ecological architecture of Frei Otto, which shows the relation between human beings and architecture, presents diverse possibilities of the archtectural space as a complex natural system, which is more than a simple combination of separatge elements.

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New Continuous Variable Space Optimization Methodology for the Inverse Kinematics of Binary Manipulators Consisting of Numerous Modules (수많은 모듈로 구성된 이진 매니플레이터 역기구 설계를 위한 연속변수공간 최적화 신기법 연구)

  • Jang Gang-Won;Nam Sang Jun;Kim Yoon Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.10
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    • pp.1574-1582
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    • 2004
  • Binary manipulators have recently received much attention due to hyper-redundancy, light weight, good controllability and high reliability. The precise positioning of the manipulator end-effecter requires the use of many modules, which results in a high-dimensional workspace. When the workspace dimension is large, existing inverse kinematics methods such as the Ebert-Uphoff algorithm may require impractically large memory size in determining the binary positions of all actuators. To overcome this limitation, we propose a new inverse kinematics algorithm: the inverse kinematics problem is formulated as an optimization problem using real-valued design variables, The key procedure in this approach is to transform the integer-variable optimization problem to a real-variable optimization problem and to push the real-valued design variables as closely as possible to the permissible binary values. Since the actual optimization is performed in real-valued design variables, the design sensitivity becomes readily available, and the optimization method becomes extremely efficient. Because the proposed formulation is quite general, other design considerations such as operation power minimization can be easily considered.

A Image Feedback control of Mobile Robot for Target Tracking (모바일 로봇의 목표물 추적을 위한 이미지 궤환 제어)

  • Hwang, Won-Jun;Lee, Woo-Song
    • Journal of the Korean Society of Industry Convergence
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    • v.18 no.2
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    • pp.90-98
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    • 2015
  • This research propose with image-based visual a new approach to design a feedback control of mobile robot. because mobile robot must be recharged periodically, it is necessary to detect and move to docking station. Generally, laser scanner is used for detect of position of docking station. CCD Camera is also used for this purpose. In case of using camera, the position-based visual servoing method is widely used. But position-based visual servoing method requires the accurate calibration and it is hard and complex work. Another method using cameras is inmage-based visual feedback. Recently, image based visual feedback is widely used for robotic application. But it has a problem that cannot have linear trajectory in the 3-dimensional space. Because of this weak point, image-based visual servoing has a limit for real application. in case of 2-dimensional movement on the plane, it has also similar problem. In order to solve this problem, we point out the main reason of the problem of the resolved rate control method that has been generally used in the image-based visual servoing and we propose an image-based visual feedback method that can reduce the curved trajectory of mobile robot in th cartesian space.