scholarly journals ESTIMATING NORMAL DURATION OF RENOVATION FOR MULTISTORY APARTMENT BUILDING CONSIDERING EXTENSION-TYPE RENOVATION PROJECTS

2019 ◽  
Vol 25 (2) ◽  
pp. 156-167
Author(s):  
Jongsik Yoon ◽  
Ilhan Yu
Keyword(s):  
Critical Path ◽  
Project Control ◽  
Apartment Building ◽  
Project Duration ◽  
Baseline Schedule ◽  
Vertical Extension ◽  
Initial Stage ◽  
Proposed Model ◽  
Normal Duration

Normal (typical) project duration is estimated at the initial stage of a renovation project and is an important reference for project control. However, its estimation has not been researched extensively owing to the complexity and uncertainties of renovation. Thus, a model was developed for predicting the duration of sustainable apartment renovation. Experts were asked to estimate a baseline schedule for extension-type renovation projects, factors that influence critical path activities, and the range of project durations considering these factors. An equation for estimating the duration of a renovation project was developed, and the range of project durations was derived using a MCS to reflect uncertainty. The proposed model was validated by applying it to actual cases. The case study shows that the model would be more suitable for complex renovation construction (i.e., more than two buildings or vertical extension). The model can be applied to various renovation projects and used as a reference for determining contract time. It can fill the knowledge gap of construction duration forecasting by adapting the concept of control activities to simplify the assessment of uncertainties in renovation of apartments, and can be applied for forecasting sustainable renovation time for other project types or in other locations.

scholarly journals A Cost Optimization Model for Multiresource Leveling Problem without Project Duration Constraint

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Qingyou Yan ◽  
Qian Zhang ◽  
Xin Zou
Keyword(s):  
Optimization Model ◽  
Cost Optimization ◽  
Resource Usage ◽  
Project Duration ◽  
Resource Demand ◽  
Resource Leveling ◽  
Proposed Model ◽  
Liquidated Damages ◽  
The Relationship

The study of traditional resource leveling problem aims at minimizing the resource usage fluctuations and obtaining sustainable resource supplement, which is accomplished by adjusting noncritical activities within their start and finish time. However, there exist limitations in terms of the traditional resource leveling problem based on the fixed project duration. This paper assumes that the duration can be changed in a certain range and then analyzes the relationship between the scarce resource usage fluctuations and project cost. This paper proposes an optimization model for the multiresource leveling problem. We take into consideration five kinds of cost: the extra hire cost when the resource demand is greater than the resource available amount, the idle cost of resource when the resource available amount is greater than the resource demand, the indirect cost related to the duration, the liquidated damages when the project duration is extended, and the incentive fee when the project duration is reduced. The optimal objective of this model is to minimize the sum of the aforementioned five kinds of cost. Finally, a case study is examined to highlight the characteristic of the proposed model at the end of this paper.

Modelling of tri-parameter bidding integrating cost, time and risk: a stochastic approach

2017 ◽  
Vol 22 (2) ◽  
pp. 117-134 ◽  
Author(s):  
Mohamad Rabie ◽  
Sameh El-Sayegh
Keyword(s):  
Stochastic Scheduling ◽  
Stochastic Approach ◽  
Time Parameter ◽  
Content Type ◽  
Project Duration ◽  
Baseline Schedule ◽  
Schedule Flexibility ◽  
Risk Parameter ◽  
Proposed Model ◽  
Schedule Risk

Purpose This paper aims to propose a new tri-parameter bidding model integrating cost, time and risk. The key value of the model is that it remains within the framework of the competitive bidding system while controlling the risk resulting from float loss. Design/methodology/approach The model utilizes stochastic scheduling to quantify the float loss impact at the project level. Prospective bidders are evaluated based on their total combined bid (TCB) including cost, time and risk. The risk parameter is calculated as the relative risk between the bidder’s schedule and the client’s baseline schedule. Findings The results confirmed that choosing the contractor based on the lowest price and time reduces the available float and increases the schedule risks. The probability of completing the project on time dropped from 46 per cent for the baseline schedule to 19 per cent for the bidder with the most compressed schedule. The selected bidder, using the proposed model, has the lowest TCB of cost, time and risk. Results show that adding the risk parameter in the evaluation changed the ranking of the bidders. Research limitations/implications The model does not discuss all project risks that the contractor retains. It focuses on schedule risks that result from shortening project duration. The model focuses on solving the problem with price plus time bidding method by addressing the schedule risk issue. Other criteria, such as sustainability, are not considered. Practical implications The proposed model encourages contractors to pay more attention to the time parameter and the schedule risks resulting from aggressive reduction in project duration. Originality/value Problems arose, in the current complex construction industry, as owners rely solely on price as the award criterion. Recently, the bi-parameter bidding system, A + B, introduced the time parameter to the awarding criteria. However, reducing the project duration by compressing the schedule consumes the float of non-critical activities, which reduces the schedule flexibility of a project. The proposed model allows clients to evaluate potential bidders objectively. Rather than evaluating the bidders based on price, in the conventional low bid system, or based on price and time, as in the A + B system, the bidders are evaluated based on three parameters: price, time and risk.

scholarly journals ANALYSIS SCHEDULING PROJECT USING CPM METHOD (Case study : Project of the Surabaya Caspian Tower Apartment)

2020 ◽  
Vol 2 (2) ◽  
pp. 26-39
Author(s):  
Harjian Maprilana ◽  
Koespiadi Koespiadi
Keyword(s):  
Project Management ◽  
Critical Path ◽  
Project Implementation ◽  
Construction Work ◽  
Quality Of Work ◽  
Project Completion ◽  
Implementation Costs ◽  
Normal Duration

The success and failure of project implementation is often caused by poor planning and ineffective controls, so that project activities experience various obstacles such as the late completion of the project, the decline in the quality of work and the swelling of implementation costs. Project management is carried out to manage the project from the beginning of the project until the completion of the project properly. The case study in this study is PT. PP (Persero) Tbk. as the executing element of the construction work, it is in charge of organizing the construction of the Surabaya Caspian Tower Apartment in East Java. The CPM (Critical Path Method) method is used to find out how long a project has been completed and look for possible acceleration of project time. From the research using the CPM method, it can be seen that the normal duration of project completion is 453 days which can be optimized to 350 days. This can be done by giving special attention to activities included in the critical path and accelerating some activities by increasing the number of workers

Project Management Risk

2017 ◽  
pp. 127-149
Keyword(s):  
Project Management ◽  
Six Sigma ◽  
Critical Path ◽  
Project Control ◽  
Project Risk ◽  
Project Duration ◽  
Stochastic Techniques ◽  
Simulation Results ◽  
Critical Paths ◽  
Associated Risk Factors

Presented method is applied to Project Management by using PERT-CPM critical paths to manage project risk. DMAIC framework applies stochastic techniques. Stochastic optimisation determines the critical paths. Every critical path is simulated and associated risks are calculated. Six Sigma process metrics are calculated against specified targets. Simulation results are analysed and sensitivity analysis is used to identify and quantify the main contributors to the variability of the project duration time. The critical paths are ranked and prioritised for management's attention based on their associated risk factors. The project was not implemented, so there no data for analysis. However, assuming that the project was implemented, a generic Project Control phase is applied.

Devising extended-duration schedules of enhanced resource leveling

2015 ◽  
Vol 42 (8) ◽  
pp. 552-562 ◽  
Author(s):  
Mohammed Abdul Rahman ◽  
Ashraf Elazouni
Keyword(s):  
Critical Path ◽  
Optimal Solutions ◽  
Efficient Utilization ◽  
Project Duration ◽  
Resource Leveling ◽  
Extended Duration ◽  
Management Techniques ◽  
Resource Conditions ◽  
Genetic Algorithm Model

The use of resource management techniques is crucial to resolve conflicts and achieve the efficient utilization of resources. Particularly, resource-leveling techniques schedule activities in unconstrained-resource conditions to minimize fluctuations in resource profiles. According to the literature, resource leveling has typically been performed by considering that the original project duration remains fixed. Virtually, some extension in the project duration might be acceptable should a considerable enhancement in resource leveling be achieved. This paper enhances resource leveling through devising schedules of extended duration that exhibit resource profiles of lower fluctuation. Critical path method (CPM) networks of extended total floats are utilized to provide expanded yet definite spaces to search for schedules of lower resource fluctuation. The modified CPM networks accommodate for employing optimization models and searching optimal or near-optimal solutions. For demonstration, a genetic algorithm model was formulated to solve two case-study networks of 30 and 120 activities. The results indicate that schedules of lower fluctuation in resource profiles were obtained beyond the original networks’ duration.

STUDI ANALISIS BIAYA DAN WAKTU MENGGUNAKAN METODE TIME COST TRADE OFF (TCTO) PADA PROYEK TELKOM MANYAR-SURABAYA.

EXTRAPOLASI ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 20-29
Author(s):  
Rizal Rosyid ◽  
Gede Sarya ◽  
Michella Beatrix ◽  
Wateno Oetomo
Keyword(s):  
Critical Path ◽  
Working Hours ◽  
Time Cost ◽  
Time Duration ◽  
Project Cost ◽  
Trade Off ◽  
Project Duration ◽  
Network Diagram ◽  
Schedule Compression ◽  
Normal Duration

AbstractTime cost trade off is a schedule compression to get projects that are more profitable in terms of time (duration), costs, and income. The aim is to compress the project to an acceptable duration and minimize the total project cost. The reduction in project duration is done by selecting certain activities. The analysis begins by preparing a network diagram (network diagram) using Microsoft Project. After that the crashing process is done using the addition of workers and additional hours of work contained in the critical path. Next do the calculations with the time cost trade off method to find the value of the crash cost and cost slope contained in the critical path. From the results of the analysis, the normal duration of the project is 639 calendar days after the process of crashing, adding work hours to 622 days and labor to 623 calendar days and the initial project cost of Rp. 250,320,084,731 after the process of crashing activities with an alternative addition to labor obtained a fee of Rp. 250,559,140,422 and additional working hours in the amount of Rp. 252,734,398,495. So that it can be concluded with the time cost trade off method there is a reduction in the duration and increase in costs.AbstrakTime cost trade off merupakan kompresi jadwal untuk mendapatkan proyek yang lebih menguntungkan dari segi waktu (durasi), biaya, dan pendapatan. Tujuannya adalah memampatkan proyek dengan durasi yang dapat diterima dan meminimalisasi biaya total proyek. Pengurangan durasi proyek dilakukan dengan memilih aktivitas tertentu. Analisa dimulai dengan melakukan penyusunan jaringan kerja ( network diagram ) dengan menggunakan microsoft project. Setelah itu dilakukan proses crashing menggunakan penambahan pekerja dan penambahan jam kerja yang terdapat pada jalur kritis. Selanjutnya melakukan perhitungan dengan metode time cost trade off untuk mencari nilai crash cost dan cost slope yang terdapat pada jalur kritis. Dari hasil analisa yang dilakukan diperoleh durasi proyek normal 639 hari kalender setelah dilakukan proses crashing kegiatan penambahan jam kerja menjadi 622 Hari dan tenaga kerja menjadi 623 hari kalender dan biaya proyek awal sebesar Rp. 250.320.084.731 setelah dilakukan proses crashing kegiatan dengan alternatif penambahan tenaga kerja diperoleh biaya sebesar Rp. 250.559.140.422 dan penambahan jam kerja sebesar Rp. 252,734,398,495. Sehingga dapat disimpulkan dengan metode time cost trade off terjadi pengurangan durasi dan peningkatan biaya. 

scholarly journals Modeling of Emergency Supply Scheduling Problem Based on Reliability and Its Solution Algorithm under Variable Road Network after Sudden-Onset Disasters

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Tinggui Chen ◽  
Shiwen Wu ◽  
Jianjun Yang ◽  
Guodong Cong ◽  
Gongfa Li
Keyword(s):  
Road Network ◽  
Road Networks ◽  
Sudden Onset ◽  
The Road ◽  
Bee Colony ◽  
Proposed Model ◽  
Effectiveness And Efficiency ◽  
In Transit ◽  
Emergency Supply

It is common that many roads in disaster areas are damaged and obstructed after sudden-onset disasters. The phenomenon often comes with escalated traffic deterioration that raises the time and cost of emergency supply scheduling. Fortunately, repairing road network will shorten the time of in-transit distribution. In this paper, according to the characteristics of emergency supplies distribution, an emergency supply scheduling model based on multiple warehouses and stricken locations is constructed to deal with the failure of part of road networks in the early postdisaster phase. The detailed process is as follows. When part of the road networks fail, we firstly determine whether to repair the damaged road networks, and then a model of reliable emergency supply scheduling based on bi-level programming is proposed. Subsequently, an improved artificial bee colony algorithm is presented to solve the problem mentioned above. Finally, through a case study, the effectiveness and efficiency of the proposed model and algorithm are verified.

scholarly journals A New Approach to Inform Restoration and Management Decisions for Sustainable Apiculture

2021 ◽  
Vol 13 (11) ◽  
pp. 6109
Author(s):  
Joanne Lee Picknoll ◽  
Pieter Poot ◽  
Michael Renton
Keyword(s):  
Floral Resources ◽  
Pollination Services ◽  
New Approach ◽  
Honey Production ◽  
Proposed Model ◽  
Colony Loss ◽  
Supply Potential ◽  
Australian Case ◽  
Stocking Rates

Habitat loss has reduced the available resources for apiarists and is a key driver of poor colony health, colony loss, and reduced honey yields. The biggest challenge for apiarists in the future will be meeting increasing demands for pollination services, honey, and other bee products with limited resources. Targeted landscape restoration focusing on high-value or high-yielding forage could ensure adequate floral resources are available to sustain the growing industry. Tools are currently needed to evaluate the likely productivity of potential sites for restoration and inform decisions about plant selections and arrangements and hive stocking rates, movements, and placements. We propose a new approach for designing sites for apiculture, centred on a model of honey production that predicts how changes to plant and hive decisions affect the resource supply, potential for bees to collect resources, consumption of resources by the colonies, and subsequently, amount of honey that may be produced. The proposed model is discussed with reference to existing models, and data input requirements are discussed with reference to an Australian case study area. We conclude that no existing model exactly meets the requirements of our proposed approach, but components of several existing models could be combined to achieve these needs.

scholarly journals Bearing Severity Fault Evaluation Using Contour Maps—Case Study

2021 ◽  
Vol 11 (14) ◽  
pp. 6452
Author(s):  
César Ricardo Soto-Ocampo ◽  
Juan David Cano-Moreno ◽  
José Manuel Mera ◽  
Joaquín Maroto
Keyword(s):  
Health Indicators ◽  
Bearing Faults ◽  
Contour Maps ◽  
Initial Stage ◽  
Critical Components ◽  
Bearing Damage ◽  
First Time ◽  
Current Operating

Increasing industrial competitiveness has led to an increased global interest in condition monitoring. In this sector, rotating machinery plays an important role, where the bearing is one of the most critical components. Many vibration-based signal treatments are already being used to identify features associated with bearing faults. The information embedded in such features are employed in the construction of health indicators, which allow for evaluation of the current operating status of the machine. In this work, the use of contour maps to represent the diagnosis map of a bearing, used as a health map, is presented for the first time. The results show that the proposed method is promising, allowing for the satisfactory detection and evaluation of the severity of bearing damage. In this initial stage of the research, our results suggest that this method can improve the classification of bearing faults and, therefore, optimise maintenance processes.

Elastic Averaging in Flexure Mechanisms: A Muliti-Beam Parallelogram Flexure Case-Study

2006 ◽  
Author(s):  
Shorya Awtar ◽  
Edip Sevincer
Keyword(s):  
Mechanism Design ◽  
Parametric Model ◽  
Nonlinear Load ◽  
Geometric Imperfections ◽  
Geometric Imperfection ◽  
Flexure Mechanism ◽  
Important Concern ◽  
Proposed Model ◽  
Geometric Arrangements

Over-constraint is an important concern in mechanism design because it can lead to a loss in desired mobility. In distributed-compliance flexure mechanisms, this problem is alleviated due to the phenomenon of elastic averaging, thus enabling performance-enhancing geometric arrangements that are otherwise unrealizable. The principle of elastic averaging is illustrated in this paper by means of a multi-beam parallelogram flexure mechanism. In a lumped-compliance configuration, this mechanism is prone to over-constraint in the presence of nominal manufacturing and assembly errors. However, with an increasing degree of distributed-compliance, the mechanism is shown to become more tolerant to such geometric imperfections. The nonlinear load-stiffening and elasto-kinematic effects in the constituent beams have an important role to play in the over-constraint and elastic averaging characteristics of this mechanism. Therefore, a parametric model that incorporates these nonlinearities is utilized in predicting the influence of a representative geometric imperfection on the primary motion stiffness of the mechanism. The proposed model utilizes a beam generalization so that varying degrees of distributed compliance are captured using a single geometric parameter.

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