• Title/Summary/Keyword: Delay effects

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A Delay Analysis based on the Comparison of the As-planned Schedule, As-built Schedule including All Delays and As-built Schedule absent Owner Delays (계획공정표, 모든 지연을 포함한 준공공정표, 발주자 지연을 제외한 준공공정표의 비교를 통한 공기지연분석)

  • Yun Chul-Sung;Chu Hae-Keum;Kim Seon-Gyoo
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • autumn
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    • pp.426-429
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    • 2003
  • In the construction process, there are many change orders differing to the initial contracts came from the social needs and environmental changes. Most of them will impact to the construction process so that its effects occur project delays. Time extension and liquidated damage in the construction process come from schedule delay whether it is excusable or not non-excusable by the owner. However, those become the delay claims if the owner and the contractor are not agreed on this situation. One of the most important thing on the delay claims is the calculation of delay. The purpose of this study is to present the method of the time delay calculation by comparison of As-Planned schedule, As-Built schedule including all delay and As-Built schedule absent owner delay.

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Investigating Main Causes for Schedule Delay in Construction Projects in Bangladesh

  • Rahman, MD. Mizanur;Lee, Young Dai;Ha, Duy Khanh
    • Journal of Construction Engineering and Project Management
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    • v.4 no.3
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    • pp.33-46
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    • 2014
  • Delay is the most common problem in the construction industry. It has many negative effects on project's success in terms of time, cost, quality, and safety. From the literature review, a total of thirty-five factors of delay were selected. These factors were divided into seven groups related to materials, manpower, owner, consultant, contractor, construction, and external problems. This study was carried out to identify the main causes of delay for a construction project through their importance level. The importance level was determined based on the frequency of occurrence and severity of impact. The structured questionnaire has distributed to the respondents who have much experience in construction management in Bangladesh. The results of analysis indicated that top five factors of construction delay according to their level of importance are: (1) price of construction materials increased very rapidly, (2) political situation (revolution/ public strikes), (3) shortages of skilled workers, (4) poor site management and supervision by contractor, (5) incompetent/ immature subcontractors. These findings of this study are expected to be significant contributions to Bangladesh construction industry in controlling current performance of project on time overrun.

Time-Delayed and Quantized Fuzzy Systems: Stability Analysis and Controller Design

  • Park, Chang-Woo;Kang, Hyung-Jin;Kim, Jung-Hwan;Park, Mignon
    • Transactions on Control, Automation and Systems Engineering
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    • v.2 no.4
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    • pp.274-284
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    • 2000
  • In this paper, the design methodology of digital fuzzy controller(DFC) for the systems with time-delay is presented and the qualitative effects of the quantizers in digital implementation of a fuzzy controllers are investigated. We propose the fuzzy feed-back controller whose output is delayed with unit sampling period and period and predicted. the analysis and the design problem considering time-delay become very easy because the proposed controller is syncronized with the sampling time. The stabilization problem of the digital fuzzy system with time-delay is solved by linear matrix inequality(LMI) theory. Furthermore, we analyze the stability of the quantized fuzzy system. Our results prove that when quantization os taken into account, one only has convergence to some small neighborhood about origin. We develop a fuzzy control system for backing up a computer-simulated truck-trailer with the consideration of time-delay and quantization effect. By using the proposed method, we analyze the quantization effect to the system and design a DFC which guarantees the stability of the control system in the presence of time-delay.

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A Belay Prevention Algorithm of Cardiac Depolarization Wave Detection for Pacemakers or Automatic Implantable Cardioverter/Defibrillator (AICD) (이식용 심장박동기(Pacemaker) 및 심장 세동제거기 (AICD)를 위한 심장 탈분극파 검출지연 방지 알고리즘)

  • Kim, J.K.;Park, C.K.;Han, S.H.;Cho, B.S.;Huh, W.
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.1063-1066
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    • 1999
  • The delay of cardiac depolarization wave detection in the conventional pacemakers or AICD (automatic implantable cardioverter/ defibrillator, or ICD) has been overlooked. However, it is known that the delay may cause hemodynamic problems and may prevent the proper operation of a new automatic feature, automatic capture verification, that is to be appeared in the near-future devices. In order to reduce the effects of the delay, a delay prevention algorithm was developed and tested by applying three human electrograms. The algorithm set the sensing threshold just above the measured noise level to reduce the detection delay. It is found that the low threshold was able to reduce the delay by 20msec(average) In most cases. The implementation results showed reliability and efficacy of the algorithm, and the algorithm could be applicable to the existing hardware and software of the conventional pacemakers and AICD without any significant modifications.

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Energy-Efficient Scheduling with Delay Constraints in Time-Varying Uplink Channels

  • Kwon, Ho-Joong;Lee, Byeong-Gi
    • Journal of Communications and Networks
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    • v.10 no.1
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    • pp.28-37
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    • 2008
  • In this paper, we investigate the problem of minimizing the average transmission power of users while guaranteeing the average delay constraints in time-varying uplink channels. We design a scheduler that selects a user for transmission and determines the transmission rate of the selected user based on the channel and backlog information of users. Since it requires prohibitively high computation complexity to determine an optimal scheduler for multi-user systems, we propose a low-complexity scheduling scheme that can achieve near-optimal performance. In this scheme, we reduce the complexity by decomposing the multiuser problem into multiple individual user problems. We arrange the probability of selecting each user such that it can be determined only by the information of the corresponding user and then optimize the transmission rate of each user independently. We solve the user problem by using a dynamic programming approach and analyze the upper and lower bounds of average transmission power and average delay, respectively. In addition, we investigate the effects of the user selection algorithm on the performance for different channel models. We show that a channel-adaptive user selection algorithm can improve the energy efficiency under uncorrelated channels but the gain is obtainable only for loose delay requirements in the case of correlated channels. Based on this, we propose a user selection algorithm that adapts itself to both the channel condition and the backlog level, which turns out to be energy-efficient over wide range of delay requirement regardless of the channel model.

Teleoperation by using Smith prediction and Grey prediction with a Time-delay in a Non-visible Environment (스미스 예측기와 그레이 예측 방법을 적용한 시간 지연이 있는 비 가시 환경에서의 원격로봇제어)

  • Jung, JaeHun;Kim, DeokSu;Lee, Jangmyung
    • The Journal of Korea Robotics Society
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    • v.11 no.4
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    • pp.277-284
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    • 2016
  • A new prediction scheme has been proposed for the robust teleoperation in a non-visible environment. The positioning error caused by the time delay in the non-visible environment has been compensated for by the Smith predictor and the sensory data have been estimated by the Grey model. The Smith predictor is effective for the compensation of the positioning error caused by the time delay with a precise system model. Therefore the dynamic model of a mobile robot has been used in this research. To minimize the unstable and erroneous states caused by the time delay, the estimated sensor data have been sent to the operator. Through simulations, the possibility of compensating the errors caused by the time delay has been verified using the Smith predictor. Also the estimation reliability of the measurement data has been demonstrated. Robust teleoperations in a non-visible environment have been performed with a mobile robot to avoid the obstacles effective to go to the target position by the proposed prediction scheme which combines the Smith predictor and the Grey model. Even though the human operator is involved in the teleoperation loop, the compensation effects have been clearly demonstrated.

Effect of Outdated Channel Estimates on Multiple Antennas Multiple Relaying Networks

  • Wang, Lei;Cai, Yueming;Yang, Weiwei;Yan, Wei;Song, Jialei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.5
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    • pp.1682-1701
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    • 2015
  • In this paper, we propose an intergraded unified imperfect CSI model and investigate the joined effects of feedback delay and channel estimation errors (CEE) for two-hop relaying systems with transmit beamforming and relay selection. We derived closed-form expressions for important performance measures including the exact analysis and lower bounds of outage probability as well as error performance. The ergodic capacity is also included with closed-form results. Furthermore, diversity and coding gains based on the asymptotic analysis at high SNRs are also presented, which are simple and concise and provide new analytical insights into the corresponding power allocation scheme. The analysis indicates that delay effect results in the coding gain loss and the diversity order loss, while CEE will merely cause the coding gain loss. Numerical results verify the theoretical analysis and illustrate the system is more sensitive to transmit beamforming delay compared with relay selection delay and also verify the superiority of optimum power allocation. We further investigate the outage loss due to the CEE and feedback delays, which indicates that the effect of the CEE is more influential at low-to-medium SNR, and then it will hand over the dominate role to the feedback delay.

Bus Encoding for Low Power and Crosstalk Delay Elimination (저전력과 크로스톡 지연 제거를 위한 버스 인코딩)

  • 여준기;김태환
    • Journal of KIISE:Computer Systems and Theory
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    • v.29 no.12
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    • pp.680-686
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    • 2002
  • In deep-submicron (BSM) design, coupling effects between wires on the bus cause serious problems such as crosstalk delay, noise, and power consumption. Most of the previous works on bus encoding are targeted either to minimize tile power consumption on bus or to minimize the crosstalk delay, but not both. In this paper, we propose a new bus encoding algorithm that minimizes the power consumption on bus and eliminates the crosstalk delay simultaneously. We formulate and solve the problem by minimizing a weighted sum of the self transition and cross-coupled transition activities on bus From experiments using a set of benchmark designs. it is shown that the proposed encoding technique consumes at least 15% less power over the existing techniques, while completely eliminating the crosstalk delay.

The Effects of academic self-efficacy, grit, learned helplessness on academic delay behavior in college students (대학생의 학업적 자기효능감, 그릿, 학습된 무기력이 학업지연행동에 미치는 영향)

  • Hyunsu Ko;Jeongeun Yu;Eunjo Moon;Junghee Park
    • The Korean Journal of Emergency Medical Services
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    • v.27 no.3
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    • pp.101-111
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    • 2023
  • Purpose: This study attempted to identify how academic self-efficacy, grit, and learned helplessness influence Academic delay behavior in college students and provide a foundation for reducing Academic delay behavior in college students. Methods: Data was collected from October 12, 2023 to October 30, 2023 using a structured questionnaire from 170 college students at a university in City D. The data was collected using a structured questionnaire. Results: Academic delay behaviors were significantly negatively correlated with academic self-efficacy (r=-.371, p<.001) and grit (r=-.562, p=.012), and significantly positively correlated with learned helplessness (r=.341, p<.001). Conclusion: Finally, In order to reduce academic delay behaviors among college students, it is necessary to actively utilize educational environments that promote academic achievement and grit, academic-related counseling programs, and learning environments that do not suffer from academic helplessness.

Analytical Delay-Time Modeling of BICMOS Buffere (BICMOS 버퍼의 해석적 지연시간 모델링)

  • 이희덕;조인성;한철희
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.1
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    • pp.38-44
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    • 1993
  • A model for BICMOS buffer switching operation is presented, including the influence of bipolar base transit time and collector-base capacitances. A closed-form solution for the propagation delay-time is obtained assuming low level injection and channel velocity limitation. For the high level injection case, the delay-times are numerically obtained using effective current gain. These results are compared with those by HSPICE simulation, which shows good agreement. It is noted that the collector-base capacitance strongly affects the delay-time. The effects of voltage scaling are also investigated, which shows the model can be applied for the reduced supply voltages.

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