Browsing by Author "Wang, Wei-Chih"

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A factor-based probabilistic cost model to support bid-price estimation
(2012-04-01)
Wang, Wei-Chih
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Wang, Shih-Hsu
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Tsui, Yu-Kun
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Hsu, Ching-Hsiang
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土木工程學系
An appropriate bid price is essential for winning a construction project contract. However, making an accurate cost estimate is both time-consuming and expensive. Thus, a method that does not take much time and can approximate a proper bid price can help a contractor in making bid-price decisions when the available bid-estimation time is insufficient. Such a method can also generate a target cost and provide a cross-check for their bid prices that were estimated using a detailed process. This study proposes a novel model for quickly making a bid-price estimation that integrates a probabilistic cost sub-model and a multi-factor evaluation sub-model. The cost sub-model, which is simulation-based, focuses on the cost divisions to save estimation time. At the same time, the multi-factor evaluation sub-model captures the specific factors affecting the cost of each cost division. The advantages of the proposed model are demonstrated by its application to three residential housing projects located in northern Taiwan. The steps for applying this model to other contractors are also provided. (C) 2011 Elsevier Ltd. All rights reserved.
AHP- and simulation-based budget determination procedure for public building construction projects
(2008-07-01)
Lai, Yu-Ting
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Wang, Wei-Chih
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Wang, Han-Hsiang
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土木工程學系
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Department of Civil Engineering
Public construction project budgets account for a high percentage of annual government budgets. Thus, objectively determining project budgets is of priority concern for effectively allocating these budgets by government officers. However, Taiwanese regulations for setting construction project budgets only qualitatively describe the governmental administration process. Without a systematic quantitative method, government officers typically determine project budgets based on their personal experience; thus, budgeting results can be unreliable. This study presents a novel procedure for determining construction project budgets. The proposed procedure integrates an analytical hierarchy process (AHP)-based multi-criteria evaluation model with a simulation-based cost model. The AHP reflects officer evaluations with respect to budget determination criteria. Cost items are variables. The cost model generates a cumulative cost distribution for establishing project budget boundaries. The merits of the proposed procedure are demonstrated through its application to a Taiwanese project. (C) 2007 Elsevier B.V. All rights reserved.
An Activity-Based Simulation Model for Assessing Function Space Assignment for Buildings: A Service Performance Perspective
(2015-12-01)
Dzeng, Ren-Jye
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Wang, Wei-Chih
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Hsiao, Fan-Yi
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Xie, Yan-Qing
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土木工程學系
Function space assignment determines the function of all spaces and is essential to the design of a remodeled building. Optimization of function space assignment that relies upon users\' activities is difficult due to the lack of quantifiable and detailed data about users\' activities. In this paper, an activity-based simulation process model consisting of five phases is proposed and applied to an actual project. The phases include activity data collection, activity simulation, space movement pattern mining, function-space assignment optimization, movement simulation and assessment. The process also allows the building administrator to adjust the optimized assignment to accommodate hard-to-quantify preferences via a variety of indexes such as movement distance, corridor flow, and other space usage-related indexes. Results from application of the proposed model to an actual remodeling project indicated that the model offered the administrator a better assignment than the contracted architect, with a 5.79% increase in the objective function and a 23.92% decrease in movement distance. The adjusted assignment based on service-related indices, such as noise interference, further improved service by accounting for parameters that were not easily included in the objective function for optimization.
Anthradithiophene-based liquid crystal molecules: High carrier mobilities enhanced by rubbed polyimides for the application in organic field-effect transistors
(2018-06-01)
Wang, Wei-Chih
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Yeh, Tien-Tien
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Liau, Wei-Lung
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Chen, Jiun-Tai
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Hsu, Chain-Shu
We synthesize three liquid crystal molecules with angular anthradithiophene (a-ADT) as the core for the application in organic film-effect transistors (OFETs). Thiophene-octyl group and thiophene-dodecyl group are introduced on both sides of the a-ADT core to yield compounds Bis-C8T-a-ADT and Bis-C12T-a-ADT. Moreover, thiophene-dodecyl group is attached to the a-ADT core on one side to yield compound C12T-a-ADT. The synthesized compounds are measured by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) to determine their mesomorphic properties. Compound Bis-C8T-a-ADT shows nematic and smectic A phases while both compounds Bis-C12T-a-ADT and C12T-a-ADT reveal smectic A phases. The optical and electrochemical properties of the compounds are characterized by UV-vis spectroscopy and cyclic voltammetry (CV). The HOMO levels for Bis-C8T-a-ADT and Bis-C12T-a-ADT are estimated to be -5.27 eV while the HOMO level of C12T-a-ADT is estimated to be -5.34 eV. The low-lying HOMO levels of the molecules indicate their great oxidation stability in OFET devices. The carrier mobilities are observed to increase 10-1000 times using rubbed polyimide (PI), resulting from the better arrangements of the liquid crystal molecules, and excellent carrier mobilities of 1.06 and 1.02 cm(2)/Vs are obtained from compounds Bis-C12T-a-ADT and C12T-a-ADT, respectively.
APPLICATION OF IMPORTANCE-SATISFACTION ANALYSIS AND INFLUENCE-RELATIONS MAP TO EVALUATE DESIGN DELAY FACTORS
(2014-08-01)
Wang, Wei-Chih
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Lin, Chia-Li
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Wang, Shih-Hsu
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Liu, Jang-Jeng
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Lee, Ming-Tsung
Design delays can negatively influence the total completion time of a facility construction project. Knowing the factors to which design delays are most sensitive supports the time management of designs. However, factors that cause design delays are several and interrelated. This study proposes a new model to identify key factors that drive design delays. The core of the model integrates importance-satisfaction analysis (ISA) and an influence-relations map (IRM). The ISA evaluates the performance of each delay factor, while the IRM captures the causal relationships among factors. Additionally, the IRM is generated using a decision making trial and evaluation laboratory technique (DEMATEL). The model is applied to a real-world high-tech facility construction project to indicate the strengths of the model. In this investigation, four first-level delay factors and 17 second-level delay sub-factors are derived. The factor of "organization\'s decision making and budget constraints" is identified as the key driver of design delays in the project of interest. The results support management in determining which problem factors should be given priority attention. The proposed model can be employed in other decision-making situations that involve interrelated factors.
Application of project-based change management in construction: a case study
(2015-01-02)
Chen, Chun-Sung
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Tsui, Yu-Kun
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Dzeng, Ren-Jye
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Wang, Wei-Chih
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土木工程學系
Real-time information is vital to enhance dynamic control and management via information sharing and analysis in order to reduce construction conflicts and project delays. However, most construction project management programs are ineffective for project prompt responses, especially with respect to change management. This work presents a novel construction project management system called the web project-based change management (WPCM) system. The WPCM system responds to changes in information efficiently in order to facilitate change management among project participants (e.g. general contractor, suppliers, and subcontractors) in a construction project environment. Capable of increasing information sharing in construction change management, web-based technology can also provide cost savings via the Internet. A case study involving a commercial building project in Taiwan demonstrates the effectiveness of both the proposed WPCM system and information sharing in change control during the construction phase. In addition to increasing the efficiency of change control and management for a general contractor, as well as dynamic project tracking and management, the proposed system enables subcontractors and suppliers to access and manage the change information timely. Future work should implement the system functions comprehensively and apply the system to additional projects more strictly for further verification of its reliability.
Applying building information modeling to integrate schedule and cost for establishing construction progress curves
(2016-12)
Wang, Kun-Chi
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Wang, Wei-Chih
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Wang, Han-Hsiang
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Hsu, Pei-Yuan
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Wu, Wei-Hao
A cost-based progress curve (called S-curve) is often used to control construction project schedules. To establish a progress curve, the costs that are associated with each scheduling activity must be determined. However, the distributions of the quantities (costs) of cost items among various activities are time-consuming to obtain and error prone, yielding an unreliable S-curve. This work proposes the use of three-dimensional building information model (BIM) objects to integrate schedule and cost by using the powerful BIM for data acquisition and storage. BIM objects are incorporated into a proposed four-step model to establish construction progress curves. The proposed model defines search criteria (cost item, object, floor, and zone) that precisely identify takeoff objects for extracting the quantities of cost items associated with each activity. The BIM uses keynote, assembly code, and family type catalog functions to provide pop-up menus for the efficient identification of cost items that are associated with each object to preventing errors in the manual typing of cost-item names. Finally, this work demonstrates that uploading the cost items and unit prices into cost estimation software in advance is critical to automating cost estimations in BIM. (C) 2016 Elsevier B.V. All rights reserved.
Applying building information modeling to support fire safety management
(2015-11-01)
Wang, Shih-Hsu
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Wang, Wei-Chih
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Wang, Kun-Chi
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Shih, Shih-Yu
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土木工程學系
Building information modeling (BIM) is useful in three-dimensional (3D) visualization and data/information storage for planning and maintaining building projects. Recently, researchers globally have been exploring the applications of BIM. In this work, a BIM-based model is designed to support fire safety management of buildings. The model comprises four modules evacuation assessment, escape route planning, safety education, and equipment maintenance. The evacuation assessment module integrates BIM with a Fire Dynamics Simulator to calculate the required safety egress time and the available safety egress time to evaluate the ability to evacuate in case of fire. The escape route planning module utilizes BIM to determine whether the distance of an escape route is acceptable. The safety education module presents hazardous areas, videos of escape routes and directional maps, all in three dimensions, to educate the occupants of the building about fire safety. The equipment maintenance module is implemented in a web-based prototype to support maintenance tasks in a remote management manner. The results of applying BIM have demonstrated that BIM can effectively provide 3D geometric data to support the assessment and planning of fire safety (using the first three modules), and it can store information in support of safety management and property management in a web-based environment (using the equipment maintenance module). (C) 2015 Elsevier B.V. All rights reserved.
APPLYING THE AHP TO SUPPORT THE BEST-VALUE CONTRACTOR SELECTION - LESSONS LEARNED FROM TWO CASE STUDIES IN TAIWAN
(2013)
Wang, Wei-Chih
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Yu, Wen-der
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Yang, I-Tung
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Lin, Chun-Chang
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Lee, Ming-Tsung
Lately the Best-Value (BV) method for contractor selection has been receiving considerable attention in the public sector in many countries. However, the operations used in performing the BV method often differ due to the various government procurement requirements. Consequently, some of the methods popular in the academic community are not easily incorporated in the BV method in some countries. To enhance the procurement process, this study aims to gain experience by applying the well-known analytical hierarchy process (AHP) to weight the decision criteria for selecting BV contractors of two construction projects in Taiwan. Through these two case studies, this work confirms that the AHP provides a significant benefit for considering the individual preferences of all decision-makers when weighting the criteria. However, this study finds two major potential obstacles, the legal requirements associated with using the AHP and the time it takes to implement the AHP. To overcome these obstacles, this work suggests guidelines to meet the legal requirements for implementing the AHP in the BV contractor selection, and proposes several strategies to shorten the AHP implementation time. The lessons learned here are relevant to those countries in which BV method must be performed in a transparent and strictly regulated environment.
CONCEPTUAL COST ESTIMATIONS USING NEURO-FUZZY AND MULTI-FACTOR EVALUATION METHODS FOR BUILDING PROJECTS
(2017)
Wang, Wei-Chih
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Bilozerov, Tymur
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Dzeng, Ren-Jye
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Hsiao, Fan-Yi
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Wang, Kun-Chi
During the conceptual phase of a construction project, numerous uncertainties make accurate cost estimation challenging. This work develops a new model to calculate conceptual costs of building projects for effective cost control. The proposed model integrates four mathematical techniques (sub-models), namely, (1) the component ratios sub-model, fuzzy adaptive learning control network (FALCON) and fast messy genetic algorithm (fmGA) based sub-model, (2) regression sub-model, and (4) multi-factor evaluation sub-model. While the FALCON- and fmGA-based sub-model trains the historical cost data, three other sub-models assess the inputs systematically to estimate the cost of a new project. This study also closely examines the behavior of the proposed model by evaluating two modified models without considering fmGA and undertaking sensitivity analysis. Evaluation results indicate that, with the ability to more thoroughly respond to the project characteristics, the proposed model has a high probability of increasing estimation accuracies more than the three conventional methods, i.e., average unit cost, component ratios, and linear regression methods.
DEMATEL-based model to improve the performance in a matrix organization
(2012-04-01)
Wang, Wei-Chih
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Lin, Yueh-Hua
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Lin, Chia-Li
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Chung, Chu-Hsuan
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Lee, Ming-Tsung
Carrying out a design project for a high-tech facility requires a large amount of special knowledge in order to deal with the specific requirements from the client. Often the client forms a matrix organization, structured with several interrelated functional and project divisions to dictate the various requirements and needs. However, an ill-defined matrix organization is likely to result in late and inadequate decisions. This in turn may result in a poorly performing design. Identifying those divisions within the organization that perform poorly in the way they provide information for the project is critical. Therefore, this study proposes an innovative model to identify those divisions that may be responsible for the poor performance of the design project. The proposed model integrates the satisfied importance analysis (SIA) and the decision making trial and evaluation laboratory technique (DEMATEL). The SIA evaluates the performance of each division, while the DEMATEL captures the causal relationships among divisions to generate an influence-relations map. The proposed model is applied to a real-world high-tech facility design project in Taiwan to demonstrate the strengths of the model. (C) 2011 Elsevier Ltd. All rights reserved.
Establishing Construction Scheduling Progress Curve based on Buidling Information Modeling Quantity Takeoffs
(2015-01-01)
Wang, Kun-Chi
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Wu, Wei-Hao
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Hsu, Pei-Yuan
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Gansonre, Abdoul-Aziz
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Wang, Wei-Chih
A cost cumulative progress curve (called S-curve) is often used as a basis for effective schedule control which is a key to the success of construction projects. In establishing a planned S-curve of a construction project, the cost of each scheduling activity must be determined. Furthermore, the contractual costs associated with the cost items should be fully distributed to all scheduling activities. However, the relationships between scheduling activities and cost items are complex because these relationships may be 1-to-1, many-to-1 or many-to-many relations. This research proposes a searching algorithm to conduct quantity takeoffs in Revit and QTO to facilitate the establishment of the planned S-curve. The proposed search algorithm defines different search steps (using various searching parameters, such as "floor", "physical object", "cost item", and "area") to identify corresponding cost items associated with different types of activities. The benefits of the proposed algorithm is demonstrated by applying it to a high-tech facility building in northern Taiwan.
ESTABLISHING ENGINEERING S-CURVES TO EVALUATE SUPERVISION ENGINEER ALLOCATIONS FOR HIGHWAY CONSTRUCTION PROJECTS
(2016)
Wang, Shih-Hsu
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Wang, Wei-Chih
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Hsu, Pei-Yuan
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Chen, Ci-Hao
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Wang, Kun-Chi
An engineering consultant firm needs to allocate engineers to supervise a highway construction project in each month during the construction phase. Properly assigning the supervision engineers under a cost-plus-fixed-fee contract has been a key factor affecting the profitability of the firm and the quality assurance of the project. Assigning too many engineers will be a waste, while allocating too few engineers may harm the supervision quality. This work proposes a two-stage model to develop engineering S-curves (called ES-curves) for planning and controlling the engineering supervision schedule. In the planning stage, a predictive ES-curve model is established based on historical ES-curves. In the controlling stage, an ES-curve is built according to the relationships between the engineering progress and construction progress. A cluster analysis and regression analysis are applied to the model development. A case study demonstrates that the produced ES-curves can help management in planning and evaluating when to increase or decrease the number of supervision engineers assigned to a project.
Evaluating bid item prices to support contractor selection - A case study
(2007-06-01)
Lin, Chun-Chang
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Wang, Wei-Chih
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Yang, Jyh-Bin
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土木工程學系
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Department of Civil Engineering
Bid price is a highly-weighted appraisal criterion in a multi-criteria evaluation method to select contractors for construction projects. By evaluating both the magnitude and reasonableness of the bid price, this study presents an electronically-facilitated model for evaluating bid prices. The model defines a reasonable total price for a project and a reasonable cost for each cost category (or bid item) by considering the project prices estimated by the project owner and submitted by all qualified bidders. Scoring systems are then employed to score the prices submitted by bidders, and weighting methods are used to integrate the derived scores. The bidder with the highest integrated score receives the most favorable price appraisal. The merits of the proposed model are demonstrated by its successful application to a recent public construction project in Taiwan.
Face-on reorientation of pi-conjugated polymers in thin films by surface-segregated monolayers
(2020-04-07)
Wang, Wei-Chih
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Chen, Sheng-Yuan
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Yang, Yaw-Wen
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Hsu, Chain-Shu
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Tajima, Keisuke
A new pi-conjugated polymer based on naphthalenediimide with a branched semifluoroalkyl side chain (FNDIT2) was synthesized and used to change the polymer orientations in thin films. X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy revealed that FNDIT2 spontaneously forms surface-segregated monolayers in blend films with other pi-conjugated polymers to adopt a preferred face-on orientation, with the pi-plane of the polymer aligned more parallel to the surface. Thermal annealing of the films induced further reorientation of the polymers inside the films closer to the face-on orientation, as shown by two-dimensional grazing-incidence wide-angle X-ray scattering. The induced face-on orientations in the films led to higher charge mobility in the vertical direction. This study provides a general and versatile strategy to control the molecular orientation in thin films and enhance the performance of thin-film organic electronics.
Function-space assignment and movement simulation model for building renovation
(2015-07-04)
Dzeng, Ren-Jye
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Wang, Wei-Chih
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Hsiao, Fan-Yi
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土木工程學系
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Department of Civil Engineering
Building renovation is an effective way to revive the use of a building, the use efficiency of which is primarily determined by its layout. However, in architectural practice, architects and building owners renovate buildings based on their personal subjective perceptions of how occupants use the building instead of systematically analyzing their use behaviors. This study proposes a model, called the Function-space Assignment and MOvement Simulation (FAMOS) model, which integrates radio frequency identification (RFID), fast messy genetic algorithms (fmGA), and movement simulation techniques to solve the function-space assignment problem. The RFID equipment is specifically used to track the occupants\' movement data in a building, the fmGA is employed to identify the optimal result of function assignment, and the movement simulation technique is adopted to verify the result and support the decision-making of function-space assignment. This study presents a real case study to demonstrate the use of FAMOS and compare its assignments with those generated by a renovation architect. The objective function showed that FAMOS\'s version had a 14.80% higher objective value than the architect\'s version. The experiment also showed that FAMOS helped the architect find the best assignment or improve their assignment based on desired objectives such as preferred space size, minimized movement distance, or removal of corridor congestion.
Integrating building information models with construction process simulations for project scheduling support
(2014-01-01)
Wang, Wei-Chih
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Weng, Shao-Wei
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Wang, Shih-Hsu
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Chen, Cheng-Yi
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土木工程學系
Many construction practitioners and researchers have developed four-dimensional (4D) models by linking the three-dimensional (3D) components of a building information model (BIM) with the network activities of a project schedule. In such a 4D model, the BIM provides limited information, except for the 3D components. To enhance the benefits of using BIM in 4D applications, this study proposes an interface system that uses the BIMs ability with regard to quantity takeoffs of required materials (such as steel, forms, and concrete) to support site-level operations simulation, ultimately leading to the generation of a project schedule. Our proposed system includes mechanisms that collect, store, and transfer information among various software packages. Facilitated by the BIM's quantity takeoffs, the operations simulation is able to consider uncertain durations of work tasks, which allows it to consider the competing needs for resources among multiple work tasks, and to evaluate various resource allocation strategies in order to create a suitable construction plan. Finally, the resulting project schedule is also linked to the BIM 3D components, thus producing an improved BIM-based 4D model. (C) 2013 Elsevier B.V. All rights reserved.
Integration of simulation-based cost model and multi-criteria evaluation model for bid price decisions
(2007-04-01)
Wang, Wei-Chih
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Dzeng, Ren-Jye
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Lu, Yu-Huang
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土木工程學系
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Department of Civil Engineering
Several criteria affect bidding decisions. Current bidding models determine a markup based on a fixed project construction cost. This work presents a novel bid price determination procedure that is built by integrating a simulation-based cost model and a multi-criteria evaluation model. The cost model is used to consider cost uncertainties and generate a bid price cumulative distribution, whereas the multi-criteria evaluation model applies pairwise comparisons and fuzzy integrals to reflect bidder preferences regarding decision criteria. The relationship between the two models is based on a practical phenomenon in that a bidder has a high probability of winning when criteria evaluations favor his bid, and, consequently, the bidder would bid a low price, and vice versa. The merits of the proposed procedure are demonstrated by its application to two construction projects in Taiwan.
Investigation of InGaN/GaN light emitting diodes with nano-roughened surface by excimer laser etching method
(2007-01-25)
Huang, Hung-Wen
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Kao, Chih-Chiang
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Chu, Jung-Tang
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Wang, Wei-Chih
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Lu, Tien-Chang
The InGaN/GaN light emitting diodes (LEDs) with a nano-roughened top p-GaN surface fabricated by using Ni nano-masks and laser etching methods were demonstrated and analyzed. The experiment results observed the maximum light output power of the InGaN/GaN LED with a nano-roughened top p-GaN surface etched with the laser energy of 300 mJ/cm(2) was 1.55 times higher than that of a conventional LED, and the wall-plug efficiency was enhanced 68% at 20 mA. The series resistance of InGaN/GaN LED was reduced by 32% by the increase in the contact area of the nano-roughened surface. (c) 2006 Elsevier B.V. All rights reserved.
Model for evaluating uncertain project duration considering construction interface problems
(2014)
Wang, Shih-Hsu
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Lai, Yu-Ting
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Liu, Jang-Jeng
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Wang, Wei-Chih
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土木工程學系
Many probabilistic scheduling models have been developed to determine the duration of construction projects. However, these models are not appropriate to capture the effect of the factors that are involved construction interface problems on the durations of multiple activities. This work presents a simulation-based probabilistic scheduling model that includes the impact of construction interface problems on the duration of building projects. The proposed model is established according to an activity duration model and a work-group (WG)-based schedule network. The activity duration model is applied to reflect the effects of "general factors" on the duration of each activity; the WG-based schedule network is employed to evaluate the effects of construction interface problems on the durations of multiple activities. The results of applying the proposed model to an example project reveal that the duration of a project can be over-optimistically estimated if the effects of construction interface problems are neglected.