• Title/Summary/Keyword: system uncertainty

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A Study on the Linkage between Environmental Imact Assessment and Environmental Management System in Korea (한국에서의 EIA와 EMS의 연계방안 연구)

  • Kim, Im-Soon;Han, Sang-Wook;Kim, Hea Sam;Kang, Seon-Hong;Kim, Dae-Kwon
    • Journal of Environmental Impact Assessment
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    • v.15 no.3
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    • pp.165-178
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    • 2006
  • Environmental Impact Assessment (EIA) and Environmental Management Systems (EMS) are perceived by many to be separate environmental tools. EIA serves as a systematic and predictive tool for assessing the potentially significant impacts of developments on the environment. An EMS, on the other hand, is used to consider the key impacts of operational businesses on the environment. The main difference to note is that during the EIA process impacts on developments are predicted. A proposed development has yet to be built and therefore an element of uncertainty is associated with these assessments. With an EMS, the business or organization's processes are already in operation. Even though there is also an element of prediction involved, it is a comparatively easier task to investigate what the environmental impacts of these processes are. However, in contrast with the orientation of EIA to further development actions, EMS involves the review, assessment and incremental improvement of an existing organization's environmental effects. EMS can thus be regarded as a continuation of EIA principles into the operational stage of a policy, plan, program and project. EIA may be carried out without fully supporting necessary informations to EMS.

Locally Initiating Line-Based Object Association in Large Scale Multiple Cameras Environment

  • Cho, Shung-Han;Nam, Yun-Young;Hong, Sang-Jin;Cho, We-Duke
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.4 no.3
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    • pp.358-379
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    • 2010
  • Multiple object association is an important capability in visual surveillance system with multiple cameras. In this paper, we introduce locally initiating line-based object association with the parallel projection camera model, which can be applicable to the situation without the common (ground) plane. The parallel projection camera model supports the camera movement (i.e. panning, tilting and zooming) by using the simple table based compensation for non-ideal camera parameters. We propose the threshold distance based homographic line generation algorithm. This takes account of uncertain parameters such as transformation error, height uncertainty of objects and synchronization issue between cameras. Thus, the proposed algorithm associates multiple objects on demand in the surveillance system where the camera movement dynamically changes. We verify the proposed method with actual image frames. Finally, we discuss the strategy to improve the association performance by using the temporal and spatial redundancy.

2-D/3-D Combined Algorithm for Automatic Solder Paste Inspection (솔더 페이스트 자동검사를 위한 2-D/3-D 복합 알고리즘)

  • 조상현;이상윤;임쌍근;최흥문
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.173-176
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    • 2002
  • In this paper, we present the combined 2-D and 3-D algorithms for automatic solder paste inspection. For automatic inspection, optical system for the combined inspection and driving unit is made. One-pass run length algorithm that has fast and efficient memory space is applied to the input image fur extracting solder paste patterns. The path of probe movement is then calculated for an automatic inspection. For a fast 3-D inspection, the phase shift algorithm based on Moire interferometry is also used. In addition, algorithms used in this paper are coded by $MMX^{TM}$. A probe system is manufactured to simultaneously inspect 2-D and 3-D for 10mm$\times$10mm field of view, with resolutions of 10 $\mu\textrm{m}$for both x, y axis and 17 $\mu\textrm{m}$for z axis, and then, experiments on several PCBs are conducted. The processing times of 2-D and 3-D, excluding an image capturing, is 0.039 sec and 0.047 sec, respectively. The credible result with $\pm$ 1$\mu\textrm{m}$uncertainty can be also achieved.

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Implementation of Robust Direct Seek Control System for High-Speed Rotational Optical Disk Drives (고배속 광 디스크 드라이브를 위한 강인 직접 검색 제어 시스템의 구현)

  • Jin, Gyeong-Bok;Lee, Mun-No
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.7
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    • pp.539-546
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    • 2002
  • This paper presents a new direct seek control scheme that provides fast data access capability and robust performance for high-speed rotational optical disk drives (ODD). When a disk is rotating at a high speed to obtain fast data transfer in ODD, the magnitude and frequency of velocity disturbance caused by eccentric rotation of the disk increase in proportion to the rotational speed of the disk. Such disturbances make it almost impossible for the conventional seek control scheme to achieve stable and satisfactory seek performance. We analyze the problems that may arise when the conventional seek control scheme is applied to the high-speed rotational ODD and propose a new direct seek control scheme that will solve such problems. In the proposed scheme, a seek control system is designed such that its performance is guaranteed for a set of plants with parameter perturbations. The performance of the proposed seek control scheme is shown by experiments using a high-speed rotational ODD.

Magnetic Field Standards Using Magnetic Resonance

  • Park, Po Gyu;Kim, Wan-Seop;Joo, Sung Jung;Lee, Hyung Kew
    • Journal of the Korean Magnetic Resonance Society
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    • v.21 no.1
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    • pp.7-12
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    • 2017
  • The nuclear magnetic resonance (NMR) and atomic magnetic resonance (AMR) plays a fundamental role in achieving a high accuracy of magnetic field measurements. Magnetic field unit (T) was realized based on the shielded proton gyromagnetic ratio (${\gamma}^{\prime}_P$), helium-4 gyromagnetic ratio (${\gamma}_{4He}$) and related techniques. The magnetic field standard system has been disseminated by the NMR magnetometer and electromagnet, a Helmholtz coil system, and AMR magnetometer in the nonmagnetic laboratory. A magnetic field standard below 1 mT has been developed by using Cs and Cs- $^4He$ AMR with automatic compensation of an external magnetic field noise. The standards serve for the calibration of magnetometers and support the test of sensors and materials in the range from $5{\mu}T$ to 2.0 T with (1 to 50) ${\mu}T/T$ uncertainty (k=2).

Reliability Evaluation of a Microgrid Considering Its Operating Condition

  • Xu, Xufeng;Mitra, Joydeep;Wang, Tingting;Mu, Longhua
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.47-54
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    • 2016
  • Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

Optimization of Geometric Dimension & Tolerance Parameters of Front Suspension System for Vehicle Pulls Improvement (차량 쏠림 개선을 위한 전륜 현가시스템의 기하공차 최적화)

  • Kim, Yong-Suk;Jang, Dong-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.9
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    • pp.903-912
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    • 2009
  • This study is focused on simulation-based dimensional tolerance optimization process (DTOP) to minimize vehicle pulls by reduction of dimensional variation in front suspension system. In previous studies, the effect of tires and wheel alignment sensitivity have mainly been investigated to eliminate vehicle pulls in nominal design condition without allocating optimal tolerance level for selected components, among various factors regarding vehicle pulls such as vehicle design parameters, vehicle weight balance, tires, and environmental factors. Unfortunately, there are wide variations in the real vehicle, and these have impacted actual vehicle pulls, especially wheel alignment effects from suspension geometry variation has not been considered in the previous studies. In the tolerance design of suspension, tolerance variables with the uncertainty such as parts dimensional variation, assembly process, datum position and direction, and assembly tool tolerance has a great influence on the variation of the suspension dimensional performances. This study introduces total vehicle pull prediction model in considering major key factors for vehicle pull sensitivity. The Monte Carlo-based tolerance analysis model using Taguchi robust method is developed to optimize dimensional tolerance parameters, satisfying on the target variation level.

Study on Reserve Requirement for Wind Power Penetration based on the Cost/Reliability Analysis

  • Shin, Je-Seok;Kim, Jin-O;Bae, In-Su
    • Journal of Electrical Engineering and Technology
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    • v.12 no.4
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    • pp.1397-1405
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    • 2017
  • As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

Cultural Diversity and Communication Barrier (문화적 다양성이 커뮤니케이션에 미치는 영향)

  • Yang, Chun-hee
    • Journal of Distribution Science
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    • v.3 no.2
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    • pp.121-142
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    • 2005
  • We're living in a world of one global village. The globalization of business is acceleration as more companies cross national borders to find customers, materials and money. Many foreign companies and organizations are doing their business aggressively in Korea and many Korean companies and rushing into foreign market. When people communicate for business with someone from another culture, there could be difficult communication barriers to overcome resulting from differences in their values, beliefs, norms for behavior, expectations, attitudes and so on. To do successfully business, we need to understand culture background and communication style that is different from nation, race, language. Communication barriers stemming from cultural differences may vary. Largely, they can be divided into value system, non-verbal communication, and perception process. Value system can be divided into individualism versus group orientation, avoidance of uncertainty degree, power distance, and high- context culture versus low-context culture. Also non-verbal communication method and perception process may play decisive roles in communication effectiveness. Especially nonverbal communication barriers which sometimes play more important roles than the verbal parts are composed of eye contact, gesture, kinesics, proxemics, chronemics, paralanguage and language of color Cross-cultural communication affect business situation. I expect that if we understand cultural background, and then we overcome cross-cultural communication barriers. To overcome and to adapt inter-cultural business, we need to develope curriculum on the cross-cultural education which I will study in the next paper.

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Nonlinear analysis of the RC structure by higher-order element with the refined plastic hinge

  • IU, C.K.
    • Computers and Concrete
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    • v.17 no.5
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    • pp.579-596
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    • 2016
  • This paper describes a method of the refined plastic hinge approach in the framework of the higher-order element formulation that can efficaciously evaluate the limit state capacity of a whole reinforced concrete structural system using least number of element(s), whereas the traditional design of a reinforced concrete structure (i.e. AS3600; Eurocode 2) is member-based approach. Hence, in regard to the material nonlinearities, the efficient and economical cross-section analysis is provided to evaluate the element section capacity of non-uniform and arbitrary concrete section subjected to the interaction effects, which is helpful to formulate the refined plastic hinge method. In regard to the geometric nonlinearities, this paper relies on the higher-order element formulation with element load effect. Eventually, the load redistribution can be considered and make full use of the strength reserved owing to the redundancy of an indeterminate structure. And it is particularly true for the performance-based design of a structure under the extreme loads, while the uncertainty of the extreme load is great that the true behaviour of a whole structural system is important for the economical design approach, which is great superiority over the conservative optimal strength of an individual and isolated member based on traditional design (i.e. AS3600; Eurocode 2).