scholarly journals Comparative Study of Pipeline Deliverables using Deterministic and Stochastic Models

2019 ◽  
Vol 4 (1) ◽  
pp. 115-122
Author(s):  
Ernest Oria Ihendeson ◽  
Awajiogak A Ujile ◽  
Anthony K. Leol
Keyword(s):  
Stochastic Model ◽  
Construction Projects ◽  
Deterministic Model ◽  
Critical Path ◽  
Project Schedule ◽  
Construction Time ◽  
Planning And Scheduling ◽  
Pipeline Construction ◽  
Stochastic Duration ◽  
Model Variable

This study aim to proffer solution to the factors causing delay is pipeline construction project deliverables, it compared deterministic model (variable with certainty) and stochastic model (variable with uncertainty), with Six (6) planned project schedules of Brownfield Energy Service Limited for pipeline construction. Time assigned to critical activities, identified from a network analysis, with the aid of the Critical Path Method, expected mean time, both deterministic and stochastic duration was calculated. Program Evaluation Review Techniques (PERT), the variance and standard deviation of the critical activities were also calculated. The probability of completion of a project within a given period was gotten with PERT. Comparing the results for deterministic duration 60 days to 79 days, which is 50% compared to 64%. It was concluded that stochastic model is preferable when scheduling and executing pipeline construction projects, because uncertainties are factored into the planning and scheduling process including delays. Delays during execution stage, occurs mainly due to community related issues, equipment failures, change in job scope and work- men antics but not limited to these. This study advocates elimination of causes of delay, especially before and during project execution phase. It also suggested that every project schedule should follow an order of precedents, prerequisite, and management involvement and cooperation at all stages of the project

scholarly journals Effective Project Scheduling Under Workspace Congestion and Workflow Disturbance Factors

2014 ◽  
Vol 2 (1) ◽  
pp. 35 ◽  
Author(s):  
Vitaly Semenov ◽  
Anton Anichkin ◽  
Sergey Morozov ◽  
Oleg Tarlapan ◽  
Vladislav Zolotov
Keyword(s):  
Project Scheduling ◽  
Construction Projects ◽  
Critical Path ◽  
Resource Utilisation ◽  
Scheduling Problem ◽  
Priority Rules ◽  
Planning And Scheduling ◽  
Advanced Planning ◽  
Project Scheduling Problem ◽  
Spatio Temporal

Effective project management implies the use of advanced planning and scheduling methods that allow to determine feasible sequences of activities and to complete a project on time and on budget. Traditional scheduling tools like fundamental Critical Path Method (CPM) and various methods for Resource Constrained Project Scheduling Problem (RCPSP) and Time Constrained Project Scheduling Problem (TCPSP) have many shortcomings for construction projects where spatial factor plays a critically important role. Previous attempts to interpret space as a specific resource were successful for particular problems of line-of-balance scheduling, space scheduling, dynamic layout planning, horizontal and vertical logic scheduling, workspace congestion mitigating, scheduling multiple projects with movable resources, spatial scheduling of repeated and grouped activities and motion planning. However, none of these methods considers the spatio-temporal requirements in a holistic framework of generic RCPSP problem and provides feasible results accounting for workspace and workflow factors. In this paper we start with the classical RCPSP statement and then present mathematically strong formalisation of the extended generalised problem, taking into account workspace congestion and workflow disturbance constraints specified in practically meaningful and computationally constructive ways. For the generalised RCPSP problem an effective scheduling method is proposed. The method tends to minimise the project makespan while satisfying timing constraints and precedence relations, not exceeding resource utilisation limits, avoiding workspace congestions and keeping workflows continuous. The method reuses so-called serial scheduling scheme and provides for additional computational routines and heuristic priority rules to generate feasible schedules satisfying all the imposed requirements. Advantages of the method and prospects for its application to industrial needs are outlined in the paper too.

MITIGATING CONSTRUCTION PROJECT SCHEDULE OVERRUNS

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Mulenga Mukuka ◽  
Clinton Aigbavboa ◽  
Wellington Thwala
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Construction Project ◽  
Project Planning ◽  
The Body ◽  
Mitigation Measures ◽  
Primary Data ◽  
Project Schedule ◽  
Gauteng Province ◽  
Planning And Scheduling

There are many factors that contribute to the causes of schedule overruns in construction projects. This ranges from factors inherent in the technology and its management, to those resulting from the physical, social, and financial environment. Schedule overruns can give rise to disruption of work and loss of productivity, late completion of project, increased time related costs and third party claims and abandonment or termination of contract. Schedule overruns are costly and often result in disputes and claims. Hence, the need to identify mitigation measures of construction projects overruns that will bring about the timely delivery of construction projects. This paper assesses the measures to mitigate against construction projects schedule overruns in the Gauteng Province construction industry in South African. The data used in this paper were derived from both primary and secondary sources. The primary data were collected through a questionnaire distributed to construction professionals in the study area. Data received from the questionnaires were analyzed using descriptive statistics procedures. Findings revealed that proper project planning and scheduling, effective strategic planning, site management and supervision, amongst others, were the major mitigation measures of construction projects schedule overruns in the Gauteng Province of South Africa. This study contributes to the body of knowledge on the subject of the measures of mitigating against construction project schedule overruns in the Gauteng Province construction industry.

Location-based planning and scheduling of highway construction projects in hilly terrain using GIS

2018 ◽  
Vol 45 (7) ◽  
pp. 570-582 ◽  
Author(s):  
Sunil Sharma ◽  
V.K. Bansal
Keyword(s):  
Construction Projects ◽  
Spatial Information ◽  
Critical Path ◽  
Highway Construction ◽  
Large Network ◽  
Hilly Terrain ◽  
Planning And Scheduling ◽  
Execution Plan ◽  
Planning Methods ◽  
Traditional Construction

Traditional construction planning methods like bar charts and critical path method have been found inefficient for repetitive projects like highways. Location-based planning has the ability to simplify a large network of repetitive activities into an easy to understand graphical format. Highway construction projects in hilly terrain involve a variety of spatial and non-spatial information. Availability of all information in a single platform like geographic information system (GIS) has the ability to significantly improve the efficiency and accuracy of developing the execution plan. In the present study, a GIS-based location-based planning methodology is proposed for highway construction projects in hilly terrain. To demonstrate the capabilities of GIS, a location-based plan was developed for a highway project being constructed in hilly terrain. The study concludes that GIS can be utilized as a standalone system for developing a comprehensive location-based plan for highway construction projects in hilly terrain.

scholarly journals BIM Based Time Management Among Construction Contractors in Turkey

2021 ◽  
Author(s):  
Ayşen Saraç Çıracıoğlu ◽  
Hakan Yaman
Keyword(s):  
Time Management ◽  
Construction Projects ◽  
Critical Role ◽  
Scheduling Problems ◽  
Project Schedule ◽  
Structured Interviews ◽  
Planning And Scheduling ◽  
Construction Companies ◽  
Planning Department ◽  
Industrialised Countries

In both developing and industrialised countries, due to numerous time-related problems of construction projects, BIM-based time management, 4D BIM, plays an increasingly critical role within the industry. This study investigates the planning and scheduling problems, BIM application level, and BIM-based scheduling implementation by the lead construction companies in Turkey. Despite the critical importance of the planning department in construction companies, the planning and BIM integration levels have scarcely been investigated from the contractor perspective in Turkey. This paper presents the outcomes of 16 semi-structured interviews (SSI) with managers of the leading Turkish contractors selected from 100 of ENR’s 2019 Top 250 International Contractors list; a list of issues are outlined. The current situation escalates problems like tendering with missing project documents, examining 2D project drawings while scheduling, fragmentation, project manager’s reluctance to use and follow the project schedule, issues with updating the schedule as per construction improvements and quantities, and a lack of investment for BIM implementation. The research findings, ultimately, aim to help contractors improve their processes. Although this study’s findings are obtained from interviews with lead Turkish contractors, it is not limited in terms of geographic context since the interviewed contractors work worldwide.

scholarly journals Stochastic and deterministic mathematical model of cholera disease dynamics with direct transmission

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Getachew Teshome Tilahun ◽  
Woldegebriel Assefa Woldegerima ◽  
Aychew Wondifraw
Keyword(s):  
Mathematical Model ◽  
Stochastic Model ◽  
Deterministic Model ◽  
Equilibrium Points ◽  
Invariant Solution ◽  
Stochastic Approach ◽  
Disease Dynamics ◽  
Treatment Rate ◽  
Invariant Region ◽  
Contact Transmission

AbstractIn this paper we develop a stochastic mathematical model of cholera disease dynamics by considering direct contact transmission pathway. The model considers four compartments, namely susceptible humans, infectious humans, treated humans, and recovered humans. Firstly, we develop a deterministic mathematical model of cholera. Since the deterministic model does not consider the randomness process or environmental factors, we converted it to a stochastic model. Then, for both types of models, the qualitative behaviors, such as the invariant region, the existence of a positive invariant solution, the two equilibrium points (disease-free and endemic equilibrium), and their stabilities (local as well as global stability) of the model are studied. Moreover, the basic reproduction numbers are obtained for both models and compared. From the comparison, we obtained that the basic reproduction number of the stochastic model is much smaller than that of the deterministic one, which means that the stochastic approach is more realistic. Finally, we performed sensitivity analysis and numerical simulations. The numerical simulation results show that reducing contact rate, improving treatment rate, and environmental sanitation are the most crucial activities to eradicate cholera disease from the community.

scholarly journals Collaborative supply chain planning and scheduling of construction projects

2020 ◽  
Vol 53 (2) ◽  
pp. 10761-10766
Author(s):  
Walid Elmughrabi ◽  
Oumaima Ben Sassi ◽  
Thien-My Dao ◽  
Amin Chabaane
Keyword(s):  
Supply Chain ◽  
Construction Projects ◽  
Supply Chain Planning ◽  
Planning And Scheduling

scholarly journals Scheduling Optimization of Prefabricated Construction Projects by Genetic Algorithm

2021 ◽  
Vol 11 (12) ◽  
pp. 5531
Author(s):  
Linlin Xie ◽  
Yajiao Chen ◽  
Ruidong Chang
Keyword(s):  
Project Scheduling ◽  
Construction Projects ◽  
Resource Constraints ◽  
Construction Project ◽  
Engineering Application ◽  
Project Schedule ◽  
Scheduling Optimization ◽  
Implementation Method ◽  
Traditional Construction ◽  
Construction Project Scheduling

Prefabricated buildings are the direction of the future development of the construction industry and have received widespread attention. The effective execution of prefabricated construction project scheduling should consider resource constraints and the supply arrangement of prefabricated components. However, the traditional construction resource-constrained project scheduling implementation method cannot simultaneously consider the characteristics of the linkage between component production and on-site assembly construction. It cannot also fully adapt to the scheduling implementation method of the prefabricated construction projects. It is difficult to work out a reasonable project schedule and resource allocation table. In order to determine the relevant schedule parameters that can reflect the actual construction situation of the prefabricated building and meet the scheduling requirements of the prefabricated project, this study proposes a prefabricated construction project scheduling model that considers project resource constraints and prefabricated component supply constraints. Additionally, it improves the design of traditional genetic algorithms (GAs). Research results of the experimental calculation and engineering application show that the proposed project scheduling optimization model and GA are effective and practical, which can help project managers in effectively formulating prefabricated construction project scheduling plans, reasonably allocating resources, reducing completion time, and improving project performance.

STOCHASTIC PREDATION MODEL WITH DEPLETION

1979 ◽  
Vol 111 (4) ◽  
pp. 465-470 ◽  
Author(s):  
Guy L. Curry ◽  
Richard M. Feldman
Keyword(s):  
Stochastic Model ◽  
Deterministic Model ◽  
Expected Number ◽  
Numerical Comparisons ◽  
Prey Depletion

AbstractA stochastic model is developed for the expected number of prey taken by a single predator when prey depletion is apparent. The so-called “random predator equation” with prey exploitation of Royama and Rogers is compared with the stochastic model. The numerical comparisons illustrate situations where the deterministic model provides adequate and inadequate approximations.

An empirical study on non-physical waste factors in the construction industry

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Charles Igwe ◽  
Fuzhan Nasiri ◽  
Amin Hammad
Keyword(s):  
Developing Countries ◽  
Empirical Study ◽  
Construction Projects ◽  
Severity Index ◽  
Structured Interviews ◽  
Planning And Scheduling ◽  
Content Type ◽  
Normality Test ◽  
Importance Index ◽  
Human Material

PurposeThis study highlights the findings of an empirical study to investigate waste factors (WFs) affecting the performance and delivery of construction projects in developing countries. The objectives of this study are to identify non-physical WFs in developing nations and rank the identified factors based on their degree of influence on the key performance indicators (KPIs) of cost, quality and time.Design/methodology/approachIn total, 34 WFs were identified through a detailed literature review and consolidated using semi-structured interviews with construction practitioners. The statistical analysis involved a normality test using the Shapiro–Wilk test to determine if sample data have been drawn from a normally distributed population, ranking the WFs using the Frequency Index (FI), Severity Index (SI) and Importance Index (IMPI), ranking the WFs based on their effect on the project KPIs of cost, quality and time, and identify clustering structures for the identified WFs to using factor analysis (FA).FindingsThe results revealed ineffective planning and scheduling, rework/repair of defective work and resource quality problems (human, material and equipment) as the three most important WFs affecting construction projects. The factor analyses showed that WFs can be grouped into five interrelated components, suggesting the need for integrated and holistic strategies to overcome the identified WF.Practical implicationsUnderstanding the effects of WFs on construction projects is a first step towards designing holistic solutions to ensuring projects deliver value to the clients and other stakeholders. The findings of this study provide direction to construction practitioners on where to focus appropriate strategies to manage the identified WFs effectively and, therefore, improve the productivity of construction projects.Originality/valueThis study provides the first holistic analysis of WFs affecting the productivity of construction projects in developing countries.

scholarly journals Earthwork Planning and Visualisation of Time-Location Information in Road Construction Projects

2016 ◽  
Vol 1 ◽  
pp. 75
Author(s):  
R. K. Shah
Keyword(s):  
Construction Projects ◽  
Progress Monitoring ◽  
Road Construction ◽  
Resource Planning ◽  
Automatic Generation ◽  
Prototype Model ◽  
Accurate Information ◽  
Planning And Scheduling ◽  
Time Space ◽  
College Of Engineering

<p>Accurate information of locations from visual aspect is vital for efficient resource planning and managing the workspace conflicts in the earthwork operations, which are missing in the existing linear schedules. Hence, the construction managers have to depend on the subjective decisions and intangible imagining for resources allocation, workspace conflicts and location-based progress monitoring in the earthwork projects. This has caused uncertainties in planning and scheduling of earthworks, and consequently delays and cost overruns of the projects. To overcome these issues, a framework of computer based prototype model was developed using the theory of location-based planning. This paper focuses on the case study experiments to demonstrate the functions of the model, which includes automatic generation of location-based earthwork schedules and visualisation of cut-fill locations on a weekly basis. The experiment results confirmed the model’s capability in identifying precise weekly locations of cut-fill and also visualising the time-space conflicts at the earthwork projects. Hence, the paper concludes that the model is a useful decision supporting tool to improve site productivity and reduce production cost of earthworks in the construction projects like roads and railways. </p><p><em>Journal of Advanced College of Engineering and Management, Vol. 1, 2015</em>, pp. 75-84</p>

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