• Title/Summary/Keyword: Concurrent engineering

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Research of Integrated System Design Process for Concurrency Design Activity (동시적 업무수행을 위한 통합된 시스템 설계 프로세스 연구)

  • Kim Jin-Hoon;Park Young-Won
    • Journal of Korean Society for Quality Management
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    • v.32 no.3
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    • pp.141-152
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    • 2004
  • This study describes process and method to establish concurrent and/or sequential schedule planning for the system design process of the EIA632 standard. For this purpose, the study suggest Process and method that are context analysis of standard process, interface definition from activity decomposition, integration of related activities, and definition of concurrent and/or sequential work flow. The proposed process and method will contribute to minimize time loss that is emerged from activities iteration.

Separative Power of an Optimised Concurrent Gas Centrifuge

  • Bogovalov, Sergey;Borman, Vladimir
    • Nuclear Engineering and Technology
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    • v.48 no.3
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    • pp.719-726
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    • 2016
  • The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to ${\delta}U=12.7(V/700m/s)^2(300K/T)(L/1m)kg{\cdot}SWU/yr$, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

An Exposed-Terminal-Eliminated Dual-Channel MAC Protocol for Exploiting Concurrent Transmissions in Multihop Wireless Networks

  • Liu, Kai;Zhang, Yupeng;Liu, Feng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.778-798
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    • 2014
  • This paper proposes a novel exposed-terminal-eliminated medium access control (ETE-MAC) protocol by combining channel reservation, collision avoidance and concurrent transmissions to improve multi-access performance of the multihop wireless networks. Based on the proposed slot scheduling scheme, each node senses the control channel (CCH) or the data channel (DCH) to accurately determine whether it can send or receive the corresponding packets without collisions. Slot reservation on the CCH can be simultaneously executed with data packet transmissions on the DCH. Therefore, it resolves the hidden-terminal type and the exposed-terminal type problems efficiently, and obtains more spatial reuse of channel resources. Concurrent packet transmissions without extra network overheads are maximized. An analytical model combining Markov model and M/G/1 queuing theory is proposed to analyze its performance. The performance comparison between analysis and simulation shows that the analytical model is highly accurate. Finally, simulation results show that, the proposed protocol obviously outperforms the link-directionality-based dual-channel MAC protocol (DCP) and WiFlex in terms of the network throughput and the average packet delay.

Kinetic Feedback Frequency Effects on Learning Weight Shifting Skills in Nondisabled Subjects (체중이동 과제 학습시 효과적인 운동학적 되먹임 유형과 상대적 빈도)

  • Cha, Seung-Kyu;Park, So-Yeon;Chung, Jin-Ho;Kim, Young-Ho
    • Physical Therapy Korea
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    • v.7 no.1
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    • pp.55-63
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    • 2000
  • Physical therapists have been using balance and weight shifting training to induce improvements in standing and walking. This study compared the effects of kinetic feedback frequency and concurrent kinetic feedback on the performance and learning of a weight shifting skill in young, nondisabled adults. Sixteen young adults without known impairment of the neuromusculoskeletal system volunteered for the study. Subjects in each of three kinetic feedback groups performed a weight shifting task in an attempt to minimize error between their effort and a center of pressure (COP) template for a 12 second period. Feedback was provided: 1) concurrently (concurrent feedback), 2) after each trial (100% feedback), 3) after every other trial (50% feedback). Immediate and delayed (24 hour) retention tests were performed without feedback. During acquisition phase, the concurrent feedback group exhibited less error than either of the post response feedback group. For the immediate retention test, the 50% feedback group exhibited less error than did the 100% feedback and concurrent feedback. During the delayed retention, 50% feedback group displayed less error than did the other groups. But no significant differences were found between groups. These results suggest that practice with concurrent feedback is beneficial for the immediate performance, but not for the learning of this weight shifting skill. Lower frequency of feedback resulted in more permanent changes in the subject's ability to complete the task.

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Integrated Product Design Development

  • Cho, Moon-Soo;Song, Joon-Yeob
    • Journal of the Korean Operations Research and Management Science Society
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    • v.22 no.4
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    • pp.81-92
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    • 1997
  • The terminology such as ecology, environment problems, ecosystems, ecofactory, and others related to environmental problems have been recently used in manufacturing systems, since the modern industries have to consider a global ecological crisis. The indifference of recent environmental problems which may be faced now has been paid attention to all engineering areas. In this paper, manufacturing functional requirements such as disassembly, disposal, disposal, or recycling are considered in the integrated product design development, which have not been considered well in the preliminary design stage. Those functions will contribute to reduce the waste and to long the product life cycle, which also satisfies the business benefits and customer requirements. The concurrent design concepts should be applied to integrate all possible factors. Therefore, few practical concurrent engineering tools are presented in here. The objective of this paper is to develop a called green manufacturing systems for integrated product design development by concurrent design concept which can give the desirable result in product design.

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Determining the Proper Level of Spare Parts using the CSP and (r,Q) Policies in a Two-Echelon Distribution System (2계층 분배시스템에서 혼합재고정책을 이용한 적정재고수준 결정에 관한 연구)

  • Jeong, Suk-Tae;Lee, Jung-Hack;Kim, Kyung-Sup
    • Journal of the Korea Safety Management & Science
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    • v.9 no.4
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    • pp.121-127
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    • 2007
  • CSP(Concurrent Spare Parts) is supplied with the procurement of new equipment or weapon system and is used to sustain the equipment without resupply during the initial coverage period. This study is concerned with a problem of determining the near optimal inventory level of the spare parts, especially Concurrent Spare Parts. For this, we utilize the mixed periodic and continuous review polices considering the CSP and (r,Q) Policies concurrently in a two-echelon distribution system. We propose the mathematical model to minimize the total cost which is composed with ordering cost, purchasing cost, holding cost, and stickout cost. If the mixed policy is compared to other policies(CSP, (r,Q)), the proposed methodology performs well and is best policy in the equipment maintenance expenses.

CAD for process innovation in the construction industry

  • Feijo, Bruno;Gomes, Paulo C. Rodacki;Bento, Joao;Scheer, Sergio
    • Structural Engineering and Mechanics
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    • v.4 no.6
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    • pp.717-729
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    • 1996
  • This paper presents the concepts of Process Innovation and Concurrent Engineering in view of their use within Integrated CAD Systems. It follows by proposing process models that support an effective implementation. The work is practically founded on the authors' experience in performing the initial steps of implementation of some of such integrated systems for the construction industry.

Continuous Improvement Through Integration of Quality Tools

  • He, Zhen;Qi, Ershi;Liu, Zixian
    • International Journal of Quality Innovation
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    • v.3 no.2
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    • pp.38-45
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    • 2002
  • Continuous quality improvement is now the focus of research and application in quality engineering. To achieve continuous improvement, it's necessary to integrate quality tools and to plan, design and control the whole process of creating quality. Based on the extensive literature review and the philosophy of concurrent quality engineering, the paper analyzes the relationships among major quality tools such as QFD, FMEA, DOE and SPC and presents a basic model and structure for the integration of quality tools.

3-Dimensional Concurrent Geometric Modeling on High Speed Network (초고속 통신망상에서 3차원 동시 형상 설계)

  • 정운용;한순흥
    • The Journal of Society for e-Business Studies
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    • v.1 no.1
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    • pp.141-157
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    • 1996
  • Data sharing is a major challenge to implement CALS. STEP is the international standard for the product model data exchange among heterogeneous systems and plays a key role in CALS. Advances in computer networks are rapidly changing the product development processes. The network oriented modeling system premises to integrate design activities across the enterprise. To achieve goals of CALS 3-dimensional concurrent modeling that complies international standard is required since integrity and common perception of product data can be assured. This paper presents 3-dimensional concurrent geometric modeling on high speed network using STEP and methodologies.

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A Concurrent MCMA-DD Equalizer with Initial Convergence Detection (초기 수렴 검출 기능을 갖는 동시 MCMA-DD 등화기)

  • Kim, Chul-Min;Choi, Ik-Hyun;Oh, Kil-Nam;Choi, Soo-Chul
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.477-480
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    • 2005
  • CMA-DD is proposed to improve the steady-state performance of CMA and its performance is depending on switching time between two modes of operation. Castro et al. who proposed a concurrent equalizer for solving problem of CMA-DD, which reduced the sensibility of switching time. However, concurrent algorithm has a problem that it keeps working after convergence. In this paper, we propose concurrent MCMA-DD equalizer combined modified CMA(MCMA) and DD mode for making better concurrent algorithm. The proposed equalizer is better than previous algorithm in convergence speed and steady-state performance. Also, the proposed algorithm decides optimum switching time using residual ISI of the equalizer output.

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