Browsing by Author "Wu, Wei-Hao"

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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.
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.
Spatial and energetic distribution of border traps in the dual-layer HfO2/SiO2 high-k gate stack by low-frequency capacitance-voltage measurement
(2006-10-16)
Wu, Wei-Hao
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Tsui, Bing-Yue
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Chen, Mao-Chieh
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Hou, Yong-Tian
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Jin, Yin
Threshold voltage instability measured by the pulse current-voltage technique has been recognized as the transient charging and discharging of the preexisting bulk traps in Hf-based high-k gate dielectrics, and these high-k traps or called border traps can instantly exchange charge carriers with the underlying Si substrate by tunneling through the thin interfacial oxide. Based on an elastic tunneling model through trapezoidal potential barriers, the spatial and energetic distribution of border traps in the HfO2/SiO2 high-k gate stack can be profiled as a smoothed, three-dimensional mesh by measuring the low-frequency capacitance-voltage characteristics of high-k metal-oxide-semiconductor capacitors with n-type Si substrate.
Transient charging and discharging behaviors of border traps in the dual-layer HfO2/SiO2 high-k gate stack observed by using low-frequency charge pumping method
(2007-06-01)
Wu, Wei-Hao
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Tsui, Bing-Yue
;
Chen, Mao-Chieh
;
Hou, Yong-Tian
;
Jin, Yin
Transient charging and discharging of border traps in the dual-layer HfO2/SiO2 high-kappa. gate stack have been extensively studied by the low-frequency charge pumping method with various input pulse waveforms. It has been demonstrated that the exchange of charge carriers mainly occurs through the direct tunneling between the Si conduction band states and border traps in the HfO2 high-kappa. dielectric within the transient charging and discharging stages in one pulse cycle. Moreover, the transient charging and discharging behaviors could be observed in the time scale of 10(-8)-10(-4) s and well described by the charge trapping/detrapping model with dispersive capture/emission time constants used in static positive bias stress. Finally, the frequency and voltage dependencies of the border trap area density could also be transformed into the spatial and energetic distribution of border traps as a smoothed 3-D mesh profiling.