• Title/Summary/Keyword: Critical path

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Path-based new Timing Optimization Algorithm for Combinational Networks (조합논리회로를 위한 새로운 Path-Based 타이밍 최적화 알고리듬)

  • 양세양;홍봉희
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.9
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    • pp.85-93
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    • 1992
  • In this paper, the new timing optimization algorithm for combinational networks is proposed. First, we introduce the concept of P-path redundancy which is the extension of redundancy concept used in the testing of combinational networks. In this approach, the critical delay is minimized by removing the P-path redundant side inputs of the critical path, and more accurate timing optimization is possible by systematically considering the statically unsensitizable paths as well as the statically sensitizable paths. It's possible with all previous longest path based approaches that the critical delay of resulting network after timing optimization may be even increased. However, the proposed method guarantees to exclude such a possibility, and can be applied to optimize the timing of combinational networks in technology independent, and dependent phase.

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Analyses on the Workflow Critical Path (워크플로우 임계 경로에 관한 분석)

  • Son, Jin-Hyun;Chang, Duk-Ho;Kim, Myoung-Ho
    • Journal of KIISE:Databases
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    • v.28 no.4
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    • pp.677-687
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    • 2001
  • The critical path has been widely applied to many areas of computer engineering especially a directed acyclic graph. Its concept can also be useful in the context of a workflow. The workflow critical path is defined as a path which has the longest average execution time from the start activity to the end activity of workflow. Because there can be several concurrently executed workflow instances for a specific workflow a new method to determine the critical path should be developed. In this paper we specify our workflow queuing network model from which we can easily analyze many workflow characteristics. Based on this workflow model. we propose a method to identify the critical path In addition, we show come workflow areas which can utilze the critical path.

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Effects of a Standardized Critical Pathway for Gastrectomy Patients in a General Hospital (일개 종합병원의 위 절제 환자에 적용한 Critical Pathway의 효과)

  • Kim, Eun-Ok;Kwon, Soon-Man
    • Korea Journal of Hospital Management
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    • v.9 no.3
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    • pp.128-142
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    • 2004
  • To evaluate the effects of critical pathway on the length of hospital stay, the cost and quality of care provided to gastrectomy patients in a tertiary care academic medical center. The basic research design is a retrospective case-control comparative study. 470 patients of gastrectomy were included in the study; 180 before pathway development (control), 163 right after pathway implementation (path group I) and 127 one year after pathway implementation (path groupII). 476 patients of modified radical mastectomy were also analyzed to examine whether the reduction of the length of hospital stay is from the hospital-wide trend or due to the critical pathway. Death after operation, ICU stay, unplanned re-operation, readmission after discharge, the length of hospital stay and cost were analyzed. 2-test, one-way ANOVA, Bonferroni and Turkey's test were used for statistical analysis. (1) There were no significant differences in patient clinical conditions and no sign of deterioration of quality from critical pathway. (2) The length of hospital stay was 13.0 days in control group, 12.2 days in path group I and 10.0 days (p<0.01) in path groupII. (3) The total costs during the hospital stay were reduced. However the cost per day was significantly increased from reduction of hospital stay (358,488won in control, 366,017won in path group I and 413,220won (p<0.01) in path groupII). Critical pathway reduced the length of hospital stay, total hospital costs and resource utilization without harming quality of patient care.

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Complete Time Algorithm for Stadium Construction Scheduling Problem

  • Lee, Sang-Un
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.9
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    • pp.81-86
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    • 2015
  • This paper suggests heuristic algorithm with linear time complexity to decide the normal and optimal point at minimum loss/maximum profit maximum shortest scheduling problem with additional loss cost and bonus profit cost. This algorithm computes only the earliest ending time for each node. Therefore, this algorithm can be get the critical path and project duration within O(n) time complexity and reduces the five steps of critical path method to one step. The proposed algorithm can be show the result more visually than linear programming and critical path method. For real experimental data, the proposed algorithm obtains the same solution as linear programming more quickly.

Quantifying Monetary Value of Float

  • Park, Young-Jun;Lee, Dong-Eun
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.111-113
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    • 2015
  • Floats are used by the parties involved in a construction project. The owner may use float by changing order(s) or by executing risk avoidance plan; the contractor may use it for leveling resources or substituting activities' construction methods to reduce costs. Floats are accepted either just as by-product obtained by critical path method(CPM) scheduling or as asset having significant value. Succinctly, existing studies involved in float value does not consider its' changes on project time domain. It is important to identify float ownership and to quantify its' corresponding values. This paper presents a method that quantifies float value of money that changes over project execution. The method which accurately computes the monetary value of float may contributes to resolve conflicts relative to float ownership and/or delay issues among project participants. It compares the difference between the monetary value of total float - on non-critical path in each and every schedule update. It makes use of critical path method (CPM) and commercial software with which practitioners are already familiar.

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Untestable Faults Identification Using Critical-Pair Path (임계-쌍 경로를 이용한 시험 불가능 결함의 확인)

  • 서성환;안광선
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.36C no.10
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    • pp.29-38
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    • 1999
  • This paper presents a new algorithm RICP(Redundancy Identification using Critical-pair Paths) to identify untestable faults in combinational logic circuits. In a combinational logic circuit, untestable faults occurred by redundancy of circuits. The redundancy of a circuit can be detected by analyzing areas of fanout stem and reconvergent gates. The untestable faults are identified by analyzing stem area using Critical-Pair path which is an extended concept of critical path. It is showed that RICP is better than FIRE(Fault Independent REdundancy identification) algorithm in efficiency. The performance of both algorithms was compared using ISCAS85 bench mark testing circuits.

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Path planning in nuclear facility decommissioning: Research status, challenges, and opportunities

  • Adibeli, Justina Onyinyechukwu;Liu, Yong-kuo;Ayodeji, Abiodun;Awodi, Ngbede Junior
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3505-3516
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    • 2021
  • During nuclear facility decommissioning, workers are continuously exposed to high-level radiation. Hence, adequate path planning is critical to protect workers from unnecessary radiation exposure. This work discusses recent development in radioactive path planning and the algorithms recommended for the task. Specifically, we review the conventional methods for nuclear decommissioning path planning, analyze the techniques utilized in developing algorithms, and enumerate the decision factors that should be considered to optimize path planning algorithms. As a major contribution, we present the quantitative performance comparison of different algorithms utilized in solving path planning problems in nuclear decommissioning and highlight their merits and drawbacks. Also, we discuss techniques and critical consideration necessary for efficient application of robots and robotic path planning algorithms in nuclear facility decommissioning. Moreover, we analyze the influence of obstacles and the environmental/radioactive source dynamics on algorithms' efficiency. Finally, we recommend future research focus and highlight critical improvements required for the existing approaches towards a safer and cost-effective nuclear-decommissioning project.

Analysis of the Critical Path of Underground Gas Pipe According to Interference Behavior (간섭 거동에 따른 지하 가스 배관의 영향선 분석)

  • Kim, Mi-Seung;Won, Jong-Hwa;Kim, Moon-Kyum;Kim, Tae-Min;Choi, Sun-Young
    • Journal of the Korean Institute of Gas
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    • v.13 no.2
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    • pp.7-13
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    • 2009
  • In order to make the critical path analysis of gas pipeline located under rigid pipes for interference behavior, FE analysis is performed considering real buried conditions of a drain and a gas pipe according to intersection angle of two pipes. A drain pipe and gas pipe have cover depth respectively 1.0m and 3.39m and this study considers a interference angle in the range of $0{\sim}90^{\circ}$. In this paper, the critical path is analyzed from the result of Ring Deflection and bending stress according to intersection angle. In the event intersection angle of two pipes equal to the critical path of lower pipe. The analysis results show that the critical path of lower gas pipe according to interference behavior has relation to intersection angle of two pipes.

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A Critical Path Search and The Project Activities Scheduling (임계경로 탐색과 프로젝트 활동 일정 수립)

  • Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.1
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    • pp.141-150
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    • 2012
  • This paper suggests a critical path search algorithm that can easily draw PERT/GANTT chart which manages and plans a project schedule. In order to evaluate a critical path that determines the project schedule, Critical Path Method (CPM) is generally utilized. However, CPM undergoes 5 stages to calculate the critical path for a network diagram that is previously designed according to correlative relationship and execution period of project execution activities. And it may not correctly evaluate $T_E$ (The Earliest Time), since it does not suggest the way how to determine the sequence of the nodes activities that calculate the $T_E$. Also, the sequence of the network diagram activities obtained from CPM cannot be visually represented, and hence Lucko suggested an algorithm which undergoes 9 stages. On the other hand, the suggested algorithm, first of all, decides the sequence in advance, by reallocating the nodes into levels after Breadth-First Search of the network diagram that is previously designed. Next, it randomly chooses nodes of each level and immediately determines the critical path only after calculation of $T_E$. Finally, it enables the representation of the execution sequence of the project activity to be seen precisely visual by means of a small movement of $T_E$ of the nodes that are not belonging to the critical path, on basis of the $T_E$ of the nodes which belong to the critical path. The suggested algorithm has been proved its applicability to 10 real project data. It is able to get the critical path from all the projects, and precisely and visually represented the execution sequence of the activities. Also, this has advantages of, firstly, reducing 5 stages of CPM into 1, simplifying Lucko's 9 stages into 2 stages that are used to clearly express the execution sequence of the activities, and directly converting the representation into PERT/GANTT chart.

A Study on Optimal Scheduling with Directed Acyclic Graphs Task onto Multiprocessors (다중프로세서에서 비순환 타스크 그래프의 최적 스케쥴링에 관한 연구)

  • 조민환
    • Journal of the Korea Society of Computer and Information
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    • v.4 no.4
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    • pp.40-46
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    • 1999
  • The task scheduling has an effect on system execution time in a precedence constrained task graph onto the multiprocessor system. This problem is known to be NP-hard. many people made an effort to obtain near optimal schedule. We compared modified critical path schedule with many other methods(CP, MH, DL Swapping) For testing this subject, we created randomly a directed acyclic task graph with many root nodes and terminal nodes simulation result convinced for us that the modified critical path algorithm is superior to the other scheduling algorithm.

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