Predicting the critical path changes using sensitivity analysis: a delay analysis approach

2020 ◽  
Vol 13 (5) ◽  
pp. 1097-1119
Author(s):  
Mohammed Hammad ◽  
Alireza Abbasi ◽  
Ripon K. Chakrabortty ◽  
Michael J. Ryan
Keyword(s):  
Sensitivity Analysis ◽  
Probability Distribution ◽  
Critical Path ◽  
Research Work ◽  
Delay Analysis ◽  
Content Type ◽  
Project Completion ◽  
Analysis Scheme ◽  
Completion Date ◽  
Distribution Type

PurposeThis research presents a framework that allows project managers to predict the next critical paths (CP(s)) and to take extra care when planning and executing those activities that have the potential to cause changes in a project's current CP(s).Design/methodology/approachThe method presented here is based on an assessment of each activity's contribution to the overall schedule variance, which involves assigning a probability distribution function to each activity duration in the project. A sensitivity analysis is also carried out, which forms the basis of identifying which activity most affects the project completion date and therefore will have the greatest effect in changing the CP.FindingsThe authors’ analysis reveals that the most appropriate probability density function (PDF) for the targeted project is the normal distribution. However, the aim of this work is not to determine the most suitable distribution for each activity but rather to study the effect of the activity distribution type on the CP prediction. The results show that the selection of the appropriate probability distribution is very important, since it can impact the CP prediction and estimated project completion date.Originality/valueThis research work proposes a delay analysis scheme which can help the project manager to predict the next CP and to improve performance by identifying which activity is the bottleneck. On the other hand, the simplicity arises from the fact that this method does not require any expensive machines or software to generate results.

Probability Model of Corrosion Initiation Time of Steel in Concrete Structure in Chloride Environment

2011 ◽  
Vol 243-249 ◽  
pp. 5632-5636
Author(s):  
Ya Li Ma ◽  
Ai Lin Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Probability Distribution ◽  
Probability Model ◽  
Chloride Concentration ◽  
Initiation Time ◽  
Distribution Law ◽  
Corrosion Initiation ◽  
Corrosion Initiation Time ◽  
Chloride Environment ◽  
Distribution Type

Probability distribution law of corrosion initiation time of steel in concrete under chloride environment is discussed. Based on the Fick’s second law, by Monte Carlo, frequency distribution, distribution type and probability density is analyzed. The statistic parameters of the factors influencing the probability distribution of corrosion initiation time are studied and the expression for sensitivity analysis of corrosion initiation time is deduced. By sensitivity analysis can know, corrosion initiation time is found to be more sensitive to cover than the diffusion coefficient, and more sensitive to surface chloride concentration than the critical chloride level. The analysis of the paper perfects the methods of predicting the corrosion initiation time.

scholarly journals Investigation on the Effect of Probability Distribution on the Dynamic Response of Liquefiable Soils

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Juncheng Wang ◽  
Li Zhou ◽  
Wenzhi Song ◽  
Houle Zhang ◽  
Yongxin Wu
Keyword(s):  
Sensitivity Analysis ◽  
Probability Distribution ◽  
Shear Modulus ◽  
Significant Influence ◽  
Beta Distribution ◽  
Coefficient Of Variation ◽  
Site Investigation ◽  
Parameter Sensitivity Analysis ◽  
Scale Of Fluctuation ◽  
Distribution Type

This study investigated the effect of different probabilistic distributions (Lognormal, Gamma, and Beta) to characterize the spatial variability of shear modulus on the soil liquefiable response. The parameter sensitivity analysis included the coefficient of variation and scale of fluctuation of soil shear modulus. The results revealed that the distribution type had no significant influence on the liquefication zone. In particular, the estimation with Beta distribution is the worst scenario. It illuminated that the estimation with Beta distribution can provide a conservative design if site investigation is absent.

Impact of Float Loss on the Project Costs

2011 ◽  
Vol 189-193 ◽  
pp. 1532-1537
Author(s):  
Wei Lo ◽  
Yih Tzoo Chen
Keyword(s):  
Critical Path ◽  
Research Result ◽  
Optimal Schedule ◽  
Step Function ◽  
Project Cost ◽  
Traditional Concept ◽  
Project Completion ◽  
Completion Date ◽  
The Cost ◽  
The Impact

Many techniques have been developed to analyze the time impact and the costs caused by the disruptions of the project works. However, most were limited on the delay of the critical path and the overall project completion date. In recent years, although more attention has been drawn on the impact of the float loss on the overall project cost, not a single research result has been widely accepted and recognized. This study aims to fill this gap. This research firstly introduces a resource-integrated genetic algorithms (G.A.) model, which will be used to develop an optimal schedule including the timing and quantity for each type of resource required to complete each individual activity. Secondly, by using a case study this research intends to identify the impact of float loss on overall project cost through comparing the as-planned optimal schedule with an after-impacted schedule. Based on the research results this research has identified that the relationship between the float loss and project cost can be expressed as a step function and the time span of total float can be divided into and cost-related float and cost-unrelated float, termed as optimal float, in which the consumption of float will not cause the delay of the project completion date, nor the increase of project cost. The findings refute the traditional concept that the total float belongs to neither the owner nor the contractor, and suggest that the utilization float is free only within the optimal float and the float apportionment will never be reasonable unless the cost of float floss has been taken into consideration.

Estimation of operational efficiency and its determinants using DEA

2013 ◽  
Vol 7 (4) ◽  
pp. 409-429 ◽  
Author(s):  
Sudhir Kumar Singh ◽  
Vijay Kumar Bajpai
Keyword(s):  
Sensitivity Analysis ◽  
Power Plant ◽  
Regression Model ◽  
Power Plants ◽  
Research Work ◽  
Regression Result ◽  
Truncated Regression ◽  
Specific Knowledge ◽  
Content Type

Purpose – The purpose of this study is to benchmark the performance of state-owned coal-fired power plants (CFPPs) and test whether plant-specific knowledge in terms of quality of coal, size, age and make of plant contribute to an improvement in plant efficiency. Design/methodology/approach – The methodology that is utilized in the study follows a nonparametric approach of data envelopment analysis (DEA) with sensitivity analysis and Tobit regression model. The input-oriented DEA models are applied to evaluate the overall, pure technical and scale efficiencies of the CFPPs. Further, slack analysis is conducted to identify modes to improve the efficiency of the inefficient plants. Sensitivity analysis based on peer count and the removal of variables is carried out to identify the benchmark power plant. Through Tobit and bootstrap-truncated regression model, the paper investigates whether a plant's specific knowledge influences its efficiency. Findings – The DEA analysis demonstrates that nine plants are technically purely efficient.The slack analysis reveals that reducing the consumption of oil is the most effective way to improve the efficiency of inefficient plants. Mattur plant is the benchmark for most of the inefficient plants. Regression result suggests that quality of coal and size of plant significantly affect the inefficiency of the sample plants. Bharat Heavy Electrical Limited MAKE plant achieved higher efficiency in comparison to mixed MAKE. Originality/value – This study is one of the few published studies that benchmark the performance of state-owned CFPPs. This research carried out taking some new uncontrollable parameters of power plant utilities of India. Research work also identifies the possible causes of inefficiency and provides measures to improve the efficiency of the inefficient power plant.

Delay analysis in resource-constrained schedules

2009 ◽  
Vol 36 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Kyunghwan Kim
Keyword(s):  
Critical Path ◽  
Delay Analysis ◽  
Critical Path Method ◽  
Resource Constrained ◽  
Period Analysis ◽  
Analysis Techniques ◽  
Project Completion ◽  
Activity Duration ◽  
Activity Sequence ◽  
A Minor

The schedule for construction delay analysis should consider resources because it is acknowledged that a schedule without resources is not realistic. However, the conventional resource-constrained scheduling (RCS) technique is not properly operated for the widely accepted delay analysis techniques such as the contemporaneous period analysis (CPA) and the “but-for” method. The “CPM + RCS” method for rescheduling to analyze delay impacts may cause unexpected activity sequence changes and the “RCS-only” method does not reflect the time impact of the duration reduction of an activity and may cause substantial project completion delay by a minor change in the activity duration. This study analyzes the problems that arise when CPA and the “but-for” method are performed on the basis of the conventional RCS technique and shows how the resource-constrained critical path method can be utilized in those delay analyses that have advantages as compared with the RCS technique.

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

Global food safety: determinants are Codex standards and WTO's SPS food safety regulations

2014 ◽  
Vol 11 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Rajneesh Mahajan ◽  
Suresh Garg ◽  
P.B. Sharma
Keyword(s):  
Food Safety ◽  
Research Work ◽  
The Body ◽  
Successful Implementation ◽  
Processed Food ◽  
Food Sector ◽  
Content Type ◽  
Safety Regulations ◽  
Food Safety Regulations ◽  
Global Food

Purpose – The purpose of this paper is to investigate perspective in explaining how global food safety can be created through stringent implementation of Codex and World Trade Organization (WTOs) Sanitary and Phytosanitary food safety regulations and suggests the appropriate food safety system for India. Design/methodology/approach – The study has been deployed a survey questionnaire using a sample of Indian Processed food sector. In order to collect data 1,000 supply chain professional were contacted for seeking their consent to be part of the survey. Whereas total responses collected were 252 from Delhi and NCR, with response rate 25.2 percent. The data collected was empirical tested using descriptive statistics, correlation analysis, regression and ANOVA. Findings – The results and discussions indicate that all the global food safety norms laid down by WTO such as goods manufacturing practices, good hygienic practice, hazard analysis critical control point, has been developed to embody principles of safe food processing sector globally. India has also developed their food safety norms as per laid down principles by WTO. Originality/value – The present research work makes an important contribution to the body of literature on global food safety. The paper has important implications for the processed food sector since it tries to bring out practices which would help in successful implementation of global food safety standards. It is useful for academic food research as well as for processed food corporate.

scholarly journals Knowledge-based Lean Six Sigma maintenance system for sustainable buildings

2017 ◽  
Vol 8 (1) ◽  
pp. 109-130 ◽  
Author(s):  
Jasim Aldairi ◽  
M.K. Khan ◽  
J. Eduardo Munive-Hernandez
Keyword(s):  
Conceptual Framework ◽  
Six Sigma ◽  
Research Work ◽  
Lean Six Sigma ◽  
Rule Base ◽  
Sustainable Buildings ◽  
Sustainable Building ◽  
Content Type ◽  
Environmentally Sustainable ◽  
Knowledge Based

Purpose This paper aims to develop a knowledge-based (KB) system for Lean Six Sigma (LSS) maintenance in environmentally sustainable buildings (Lean6-SBM). Design/methodology/approach The Lean6-SBM conceptual framework has been developed using the rule base approach of KB system and joint integration with gauge absence prerequisites (GAP) technique. A comprehensive literature review is given for the main pillars of the framework with a typical output of GAP analysis. Findings Implementation of LSS in the sustainable building maintenance context requires a pre-assessment of the organisation’s capabilities. A conceptual framework with a design structure is proposed to tackle this issue with the provision of an enhancing strategic and operational decision-making hierarchy. Research limitations/implications Future research work might consider validating this framework in other type of industries. Practical implications Maintenance activities in environmentally sustainable buildings must take prodigious standards into consideration, and, therefore, a robust quality assurance measure has to be integrated. Originality/value The significance of this research is to present a novel use of hybrid KB/GAP methodologies to develop a Lean6-SBM system. The originality and novelty of this approach will assist in identifying quality perspectives while implementing different maintenance strategies in the sustainable building context.

Mapping the landscape of computer-assisted language learning: an inventory of research

2013 ◽  
Vol 10 (4) ◽  
pp. 252-269 ◽  
Author(s):  
Antigoni Parmaxi ◽  
Panayiotis Zaphiris ◽  
Salomi Papadima-Sophocleous ◽  
Andri Ioannou
Keyword(s):  
Language Learning ◽  
Research Work ◽  
Computer Assisted ◽  
Computer Assisted Language Learning ◽  
Card Sorting ◽  
Holistic View ◽  
Content Type ◽  
Coding Scheme ◽  
Sorting Technique ◽  
Version 2.0

Purpose – The purpose of this study is to chart the development in computer-assisted language learning (CALL), by building a map of existing research work in the field. Based on a corpus of 163 manuscripts, published between January 2009 and September 2010 in four major journals devoted to CALL, it sets out to describe the range of topics covered under the umbrella of CALL and provide a holistic view of the field. Design/methodology/approach – The approach adopted in this research includes: development of the 2009-2010 CALL corpus; literature overview and initial coding scheme development; refinement of the initial coding scheme with the help of a focus group and construction of the CALL map version 1.0; refinement of the CALL map version 1.0 following a systematic approach of content analysis and development of the CALL map version 2.0; evaluation of the proposed structure and inclusiveness of all categories in the CALL map version 2.0 using card sorting technique; and finally development of the CALL map version 3.0. Findings – The research trends in the categories of the CALL map are discussed, as well as possible future directions in the field. Originality/value – This paper provides a holistic view of the field of CALL guiding both junior CALL researchers to place themselves in the field, and policy and decision makers who attempt to evaluate the current and future scholar activity in the field. Finally, it caters for more experienced researchers to focus on certain underinvestigated domains.

Application of eco-friendly natural dye obtained from Spathodea campanulata on silk using combination of mordants

2016 ◽  
Vol 27 (1) ◽  
pp. 15-21 ◽  
Author(s):  
M Kumaresan
Keyword(s):  
Large Scale ◽  
Potassium Dichromate ◽  
Ferrous Sulphate ◽  
Research Work ◽  
Natural Dye ◽  
Alkaline Media ◽  
Silk Fabric ◽  
Content Type ◽  
Wide Range ◽  
New Research

Purpose – The purpose of this paper is to extract the eco-friendly natural dye obtained from the flower of Spathodea campanulata and apply on silk fabric using combination of mordants. The fastness properties of the flower of Spathodea campanulata dyed silk fabric have been studied using different combination (1:3, 1:1 and 3:1) of various mordants, such as myrobolan: nickel sulphate, myrobolan: aluminium sulphate, myrobolan: potassium dichromate, myrobolan: ferrous sulphate and myrobolan: stannous chloride. The wash, rub, light and perspiration fastness of the dyed samples have been evaluated. Design/methodology/approach – For dyeing there are three methods are used. They are Pre mordanting, Simultaneous mordanting and Post mordanting methods. Dyed silk materials are tested by using wash fastness, rub fastness, light and perspiration fastness methods. Findings – It is found that Spathodea campanulata dye can be successfully used for the dyeing of silk to obtain a wide range colours by using various combinations of mordants. With regards to colour fastness, test samples exhibit excellent fastness to washing, rubbing, except for pre-mordanting using myrobolan: potassium dichromate combination; and good to excellent fastness to perspiration in both acidic and alkaline media. Originality/value – Availability of literature related to this work is not available. The study of combination of mordants of this natural dye on silk is a new research work and the large scale preparation is definitely very useful to the society.

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