• 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.

• 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.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.117-121
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• 2015

Construction managers use scheduling methods to improve the outcome of their project. Despite the many obvious advantages of the critical path method (CPM), its use in construction has been limited. Understanding the reasons why CPM is not used as extensively as expected could improve its level of acceptance in the construction industry. The link between construction scheduling methods and the tasks expected to be performed by schedulers has been an on-going concern in the construction industry. This study proposes a task-technology fit model to understand why CPM is not used as extensively as expected in construction scheduling. A task-technology fit model that aims to measure the extent to which a construction scheduling method functionally matches the tasks expected to be performed by the scheduling staff. The model that is proposed is an answer to the lack of proper instruments for evaluating the extent to which scheduling methods are used in the industry.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.631-635
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• 2015

Construction managers use scheduling methods to improve the outcome of their project. In spite of the many obvious advantages of the critical path method (CPM), its use in construction has been limited. Understanding the reasons why CPM is not used as extensively as expected could improve its level of acceptance in the construction industry. The link between construction scheduling methods and the capabilities of the scheduling staff has been an on-going concern in the construction industry. This study proposes a staffing-technology fit model to understand why CPM is not used as extensively as expected in construction scheduling. A staffing-technology fit model that aims to measure the extent to which a construction scheduling method matches the staff's experience, know-how and capabilities. The model that is proposed is an answer to the lack of proper instruments for evaluating the extent to which scheduling methods are used in the industry.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.595-602
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• 2018

Network-based scheduling methods can be classified into CPM method and PERT method. In the network scheduling chart, critical path can be estimated by performing the forward calculation and the backward calculation though the paths in the network chart. In PERT method, however, it is unreasonable to simply estimate the critical path by adding the sum of the activity durations in a specific path, since it does not incorporate probabilistic concept of PERT. The critical path of a PERT network can change according to the target period and deviation, and in some cases, the expected time of the critical path may not be the path with longest expected time. Based on this concept, this study proposes a technique to derive the most-likely critical path by comparing the sum of estimated time with the target time. It also proposes a method of systematically deriving all alternate paths for a network of repetitive activities. Case studies demonstrated that the most-likely critical path is not a fixed path and may vary according to the target period and standard deviation. It is expected that the proposed method of project duration forecasting will be useful in construction environment with varying target date situations.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.445-452
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• 2011

The schedule hierarchy in construction project is generally composed of three levels. The highest level is a milestone schedule and represented by Bar Chart format. The middle level is an integrated project schedule (IPS) and represented by CPM (Critical Path Method) format. The lowest level is a detail working schedule and usually represented by Bar Chart. The traditional scheduling techniques such as ADM (Arrow Diagramming Method) or PDM (Precedence Diagramming Method) cannot represent all kinds of schedule within schedule hierarchy as identical schedule format. However, the BDM (Beeline Diagramming Method) technique can represent all kinds of schedule within schedule hierarchy as identical CPM format. This paper describes the basic concept, principle, interpretation methods, and schedule computation methods of the BDM as a new networking technique that can represent all kinds of overlapping relationships between activities, and then presents an example of representing three level's schedules within schedule hierarchy by the BDM technique.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.509-512
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• 2003

The Critical Path Method(CPM) is an effective tool used for planning and scheduling. One of strong point in the CPM is what can calculate float. Float is able to prolong without having an effect on overall schedule of project, however concept and scope about ownership is not definite, because it is a by-product of project. Thus participants have had many dispute in using float because of their interests. In recent years, a few theories have evolved in an attempt to solve this problem. But the prior research did not make a reasonable distribution of float because their criteria of distribution was based on ratio for total project time. Actually, an application of float is achieved by participant's delay risk. Therefore. this paper proposes criteria for float distribution using delay risks, and the framework for the assessment of the delay risks.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.203-214
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• 2004

This paper presents a practical application of possibilistic programming in a information system projects planning model. The estimate of the parameters of the model is often a problematic task for the decision maker(DM), Who has imprecise information or express his considerations subjectively. In this case. possibilistic decision making models can provide an important aspect in handling practical decision making problems. We suggest CPM(Critical Path Method) applying possibilistic programming. CPM is an approach to planning and coordinating large projects by directing managerial focus to the project's most critical aspects and providing completion time of project and beginning time of each activity. This model is an aid in the control of considering aspiration levels by the DM, the fuzziness of decision making, and computational efficiency. The problem is solved by using GINO computer package and the best compromised solution is found.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.391-396
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• 2013

As the construction environment has been changing all the times, the techniques for managing the construction projects have been improved accordingly. The schedule management technique, one of the construction management tools, has been evolved as well in order to be adaptable to new construction environment. Most of newly proposed scheduling techniques have been based on the Critical Path Method (CPM) that was proposed in 1956. The CPM is classified into two categories, Arrow Diagramming Method (ADM) and Precedence Diagramming Method (PDM). ADM is so good in the visual format but it cannot express the overlapping relationships between two consecutive activities. On the other hand, PDM can express the overlapping relationships but it is unsatisfactory in the visual format. Recently, as the construction environment becomes more complex and the role of schedule management becomes more and more important, the overlapping expression becomes one of critical factors for scheduling as well. Most of construction project participants prefer more comfortable visual format, however, the scheduling software based on the PDM cannot satisfy their basic requirement. Beeliner, new scheduling software based on the Beeline Diagramming Method (BDM) that was proposed in 2010, was developed in 2012, it can express more flexible overlapping relationships and has superior visual format as well. This paper presents major features and applications of Beeliner, and makes construction professionals understand new scheduling concept and its applications.

• Cement
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• s.37
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• pp.4-11
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• 1970

최근 급속히 팽창된 산업 구조와 이에 따른 업무량의 증가는 종래의 관리기술로서는 이를 성공적으로 처리할 수 없게 되었으며 아울러 인간의 미래조작능력의 증대와 기업구상력의 개발, 사회변동에 대비한 예측적인 계획의 수립 등 관리기능의 신장은 새로운 관리기법을 요구하게 되었으므로 PERT/CPM 수법이 신관리기법의 하나로 등장하게 되었다. PERT/CPM 이란 Program Evaluation Review and Technique, Critical Path Method 의 약자로서 우리말로는 계획수립 집행 및 평가로 번역되는데 이의 직역은 종속 및 총합 $\ulcorner$시스템$\lrcorner$ 과업의 동시진행 및 집중관리라 할 수 있는 것으로 시간과 비용을 절감하려는 기법인 것이다. 또한 PERT 기법은 복잡한 작업형태를 상호관련성있는 Network로 구성하고 제종속작업을 하나의 통일된 목표로 진행시키는 것을 의미한다. 이와 같은 PERT/CPM 기법은 제한된 자원의 효율적인 투자 및 관리와 불필요한 시간과 비용을 제거하여 준다. 현재 정부(경제기획원)는 PERT/CPM 제도를 도입하여 건설공사에 대한 예산관리제도를 설정중에 있으며 민간 및 정부투자기관으로서 현대건설주식회사와 한국전력주식회사와 이미 PERT/CPM 제도화방책을 연구기관에 위촉하여 제2단계적용을 시도하고 있는 것은 시대적 당위성에 따른 타당한 전망이라 하겠다. 거금 한국양회공업협회가 본제도의 도입 적용을 추진하기 위한 일련의 조사활동을 시작한 것은 시멘트 공업계의 새로운 경영관리체제를 모색하고 업계를 선도하는 중요한 전환점이 되리라 믿는다.