• 제목/요약/키워드: causes of delay

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Minimizing Data Frame in CAN Controller Area Network for Humanoid Robot (CAN 기반 휴머노이드 로봇에서의 데이터 프레임 최소화)

  • Kwon, Sun-Ku;Huh, Uk-Youl;Kim, Jin-Geol
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2806-2808
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    • 2005
  • The Controller Area Network (CAN) is being widely used for real-time control application and small-scale distributed computer controller systems. When the stuff bits are generated by bit-stuffing mechanism in the CAN network, it causes jitter including variations in response time and delay. In order to eliminate this jitter, stuff bit must be controlled to minimize the response time and reduce the variation of data transmission time. At first, this paper shows that conventional CAN protocol causes the transmission time delay. Secondly, this paper proposes the method to reduce the stuff bits by restriction of available identifier. Finally, data manipulation method can be reduced the number of stuff-bits in the data field. The proposed restriction method of ID and manipulating data field are pretty useful to the real-time control strategy with respect to performance. These procedures are implemented in local controllers of the ISHURO (Inha Semyung Humanoid Robot).

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Identification of Factors Affecting Time and Cost Performance in Vietnam Construction Projects

  • Long, Le-Hoai;Lee, Young-Dai;Lee, Jun-Yong
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.728-731
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    • 2007
  • In-planned duration and cost at project closing are the two of criteria of successful project and successful project management. In Vietnam, regularly, construction projects are delayed and their costs are overrun. This research employed a questionnaire survey to elicit the causes of this situation by interviewing 87 Vietnamese construction experts. After processing data, 21 causes of delay and cost overruns appropriate with building and industrial project in construction stage were inferred and ranked. Spearman's rank correlation tests showed that there're no differences in the viewpoints between parties in project.

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THE ROOT CAUSE ANALYSIS METHOD FOR SCHEDULE DELAY IN CONSTRUCTION (건설공사의 작업지연 원인분석방법)

  • Ji, Kun-Chang;Yu, Jung-Ho;Kim, Chang-Duk
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.131-136
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    • 2006
  • In constructing projects, there exist various kinds of work interferences, which cause a delay of the outset and completion of planned schedule because of some attributions, such as variability, uncertainty and complexity. and so schedule delay has been treated as a natural phenomenon. To reduce or prevent the schedule delay, a constant confirmation of schedule delay and a preparation of counter plans for finding out the cause structure of schedule delay should have been done. However, all this time the research has been mostly done on the calculation method or claim cases of schedule delay. Moreover, the analysis method did not consider the trait, which cause the schedule delay, in constructing projects. This paper restricts the range of the cause analysis of schedule delay to the field of site management in the projects and divides the cause structure of schedule delay into the cause objects and cause attributes of schedule delay according to the input elements. The system of classifying causes of schedule delay is examined by interviews with experts and questionnaire. Additionally, this paper analyzes the attributes of cause attributes and cause subjects and presents the analysis method and procedure of schedule delay with the application of VSM.

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The Investor's Behavior in Competitive Korean Electricity Market

  • Ahn, Nam-Sung;Kim, Hyun-Shil
    • Korean System Dynamics Review
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    • v.6 no.2
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    • pp.25-35
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    • 2005
  • This paper describes the mechanism for new investment to appear in waves of boom and bust causing alternative periods of over and under supply of electricity in Korean market. A system dynamics model was developed to describe the dynamic behavior of new investment in Korean market. The simulation results show the boom and bust cycle in the new investments. When the market price is high, investors decide to build new power plants. However, it takes some delay time to complete new power plants. When the new power plants are being added into the grid, the supply increases and the wholesale price begins to decrease. This causes the cancellation of new power plant or delay the construction. This mechanism causes the boom and bust cycle in new investment.

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Gateway Channel Hopping to Improve Transmission Efficiency in Long-range IoT Networks

  • Kim, Dae-Young;Kim, Seokhoon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.3
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    • pp.1599-1610
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    • 2019
  • Intelligent services have expanded as Internet of Things (IoT) technology has evolved and new requirements emerge to accommodate various services. One new requirement is transmitting data over long distances with low-power. Researchers have developed low power wide area (LPWA) network technology to satisfy the requirement; this can improve IoT network infrastructure and increase the range of services. However, network coverage expansion causes several problems. The traffic load is concentrated at a specific gateway, which causes network congestion and leads to decreased transmission efficiency. Therefore, the approach proposed in this paper attempts to recognize and then avoid congestion through gateway channel hopping. The LPWA network employs multiple channels, so wireless channel hopping is available in a gateway. Devices that are not delay sensitive wait for the gateway to reappear on their wireless channel; delay sensitive devices change the wireless channel along the hopping gateway. Thus, the traffic load and congestion in each wireless channel can be reduced improving transmission efficiency. The proposed approach's performance is evaluated by computer simulation and verified in terms of transmission efficiency.

Stakeholders' Perception of the Causes and Effect of Construction Delays on Project Delivery-A Review

  • Gandhak, Prajyot;Sabihuddin, Syed
    • Journal of Construction Engineering and Project Management
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    • v.4 no.4
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    • pp.41-46
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    • 2014
  • Indian Construction industry is large, volatile, and requires tremendous capital outlays. Typically, the work offers low rates of return in relation to the amount of risk involved. A unique element of risk in the industry is the manner in which disputes and claims are woven through the fibre of the construction process. Delay is generally acknowledged as the most common, costly, complex and risky problem encountered in construction projects. Because of the overriding importance of time for both the Owner and the Contractor, it is the source of frequent disputes and claims leading to lawsuits. The growing rate of delays is adversely affecting the timely delivery of construction projects. Presently construction industries are facing a lot of problems, considering that a paper assess construction stakeholder's perception to the causes of delays and its effects on project delivery. And also one case study is considered in this paper to elicit responses from construction stakeholders. The primary aim of this paper is to identify the perceptions of the different parties regarding causes of delays, the allocation of responsibilities and the types of delays, and method of minimizing the construction delays.

Metabolic evaluation of children with global developmental delay

  • Eun, So-Hee;Hahn, Si Houn
    • Clinical and Experimental Pediatrics
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    • v.58 no.4
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    • pp.117-122
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    • 2015
  • Global developmental delay (GDD) is a relatively common early-onset chronic neurological condition, which may have prenatal, perinatal, postnatal, or undetermined causes. Family history, physical and neurological examinations, and detailed history of environmental risk factors might suggest a specific disease. However, diagnostic laboratory tests, brain imaging, and other evidence-based evaluations are necessary in most cases to elucidate the causes. Diagnosis of GDD has recently improved because of remarkable advances in genetic technology, but this is an exhaustive and expensive evaluation that may not lead to therapeutic benefits in the majority of GDD patients. Inborn metabolic errors are one of the main targets for the treatment of GDD, although only a small proportion of GDD patients have this type of error. Nevertheless, diagnosis is often challenging because the phenotypes of many genetic or metabolic diseases often overlap, and their clinical spectra are much broader than currently known. Appropriate and cost-effective strategies including up-to-date information for the early identification of the "treatable" causes of GDD are needed for the development of well-timed therapeutic applications with the potential to improve neurodevelopmental outcomes.

A dynamic transmission reservation protocol with non-zero tunig delay for high-speed mutliwavelength networks (고속 광통신망에서 스위칭 오버헤드를 고려한 동적 전송 예약 프로토콜)

  • 최형윤;이호숙;김영천
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.5
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    • pp.25-34
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    • 1997
  • Relatively slow tuning speed of optical device causes the unwanted delay in high speed single-hop multiwavelength networks. To lessen the overhead, we present a channel access protocol with dynamjic message scheduling. Th eframe structure of proposed protocol adopts hybrid multiaccess scheme in which WDMA is used as a basic multiaccess technique and TDMA is used to provide subchannels within a wavelength band. This architecture has two merits : the network extention is not limited by available number of wavelengths, and the transmission delay caused by optical device tuning time can to minimize the number of tunings. It schedules messages that require same wavelength channels sequencely, so the total transmission delay is reduced by decreasement of wavelength changes. The performance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The peformance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The numeric results show that the peformance of proposed protocol is better than that of previous one.

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A Progress-based Expert System for Quantitative Assessments of Project Delay

  • Yoo, Wi Sung
    • Architectural research
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    • v.10 no.1
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    • pp.41-48
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    • 2008
  • Construction projects have frequently exceeded their schedule despite reliable estimates at the start of a project. This problem was attributed to unpredictable causes at the beginning and to shortage of proper tools to accurately predict project completion date. To supplement this difficulty, project managers need a comprehensive system that can be employed to monitor the progress of an ongoing project and to evaluate potential delay for achieving the goal on time. This paper proposed a progressive-based expert system for quantitative assessments of project delay at the early stages of the execution. Furthermore, the system is used to inspect the change of the uncertainty on completion date and its magnitude. The proposed expert system is helpful for furnishing project managers a warning signal as a project is going behind schedule and for tracking the changed uncertainty at a desired confidence level. The main objectives of this paper are to offer a new system to overcome the difficulties of conventional forecasting tools and to apply a construction project into the system to illustrate its effectiveness. This paper focuses on construction phase of project development and is intended for the use by project managers.

Error Analysis and Compensation of Measurement Delay in INS/GPS Integrated Systems with Kalman Filtering (칼만필터를 사용하는 INS/GPS 결합시스템에서 측정치 지연에 의한 오차 분석 및 보상)

  • Park, Chan-Gook;Cho, Seong-Yun;Jin, Yong
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.11
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    • pp.1039-1044
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    • 2000
  • In this paper, the error caused by the measurement delay in INS/GPS integrated systems with Kalman filtering is defined and analyzed through the analytical method and the simulation. It is proved that the error of measurement delay causes not only the position error but also the estimate error of the x-axis accelerometer bias when a vehicle turns. And the estimation method of the delay time and the compensation method using an extrapolation method are presented. The performance of the compensation method is shown by the analytic method and the simulation.

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