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尋路能力與道路環境對尋路效率影響之研究
(2009)
張新立
;
CHANG HSIN-LI
;
國立交通大學運輸科技與管理學系(所)
「尋路效率」表示一個人在尋找目的地的過程中所花費時間的長短與走錯路次數的多寡。低落的尋路效率不但會浪費時間與金錢，延誤救護與救災的時機，更可能因急於找路、產生焦慮而造成危險。尋路效率受個人之尋路能力與道路環境兩種因素所影響，個人之尋路能力因素包含了方向感、對環境之熟悉度與尋路策略之使用，而道路環境因素則包含了建築密度、地標與道路格局。本研究透過尋路能力量表之建立，並發展尋路效率的量測指標，配合不同之道路環境條件進行實驗，除可了解不同道路用路人之尋路能力差異外，更可檢視不同道路環境對尋路效率之影響效果。本研究之理論探討與實證研究結果，除可供道路設計與資訊提供之參考，亦可建立標準化之道路指引說明，提升民眾講解路線與理解道路資訊之能力。
Solution-processable tandem solid-state light-emitting electrochemical cells
(2013-12-01)
Lu, Jung-Sheng
;
Kuo, Jung-Chin
;
Su, Hai-Ching
;
照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
Compared to organic light-emitting diodes (OLEDs), solid-state light-emitting electrochemical cells (LECs) exhibit simple single-layered structure and low operating voltages due to in situ electrochemical doped layers. However, device efficiencies of LECs are usually lower than those of sophisticatedly designed OLEDs. Furthermore, device efficiencies and lifetimes of LECs degrade significantly as brightness increases. In this work, we demonstrate tandem LECs to obtain nearly doubled light outputs (mu W cm(-2)) in comparison with single-layered LECs under similar current densities. Since the output EL emission is modified by microcavity effect of the device structure, the EL spectra of tandem LECs exhibit EL emission peak at ca. 625 nm while the EL spectra of single-layered LECs center at ca. 660 nm. Better spectral overlap between the EL spectrum of tandem LECs and the luminosity function results in further enhanced candela values, rendering a tripled brightness (cd m(-2)). The device efficiencies can be optimized by adjusting the thickness of the connecting layer between the two emitting units of the tandem devices. The peak external quantum efficiency achieved in tandem LECs is up to 5.83%, which is higher than twice of that obtained in single-layered LECs due to improved carrier balance. When single-layered and tandem LECs are biased under higher voltages to reach similarly higher brightness, tandem LECs show higher device efficiencies and longer lifetimes simultaneously. These results indicate that device efficiencies and lifetimes of LECs can be improved by employing a tandem device structure. (C) 2013 Elsevier B. V. All rights reserved.
Anodic TiO2 Nanotube Arrays for Dye-Sensitized Solar Cells Characterized by Electrochemical Impedance Spectroscopy
(2012-12-01)
Wu, Hui Ping
;
Li, Lu Lin
;
Chen, Chien Chon
;
Diau, Eric Wei Guang
;
土木工程學系
This paper reports on the microstructure of anodic titanium oxide (TiO2) and its use in a dye-sensitized solar cell (DSSC) device. When voltages of 60 V were applied to titanium foil for 2 hr under 0.25 wt% NH4F + 2 vol% H2O+C2H4(OH)(2), TiO2 with a nanotube structure was formed. The film, which had a large surface area, was used as an electron transport film in the DSSC. The DSSC device had a short-circuit current density (J(sc)) of 12.52 mA cm(-2), a fill factor (FF) of 0.65, an open-voltage (V-oc) of 0.77 V, and a photocurrent efficiency of 6.3% under 100% AM 1.5 light. The internal impedance values under 100%, 64%, 11%, and 0% (dark) AM 1.5 light intensities were measured and simulated using the electrical impedance spectroscopy (EIS) technique. The impedance characteristics of the DSSC device were simulated using inductors, resistors, and capacitors. The Ti/TiO2, TiO2/Electrolyte, electrolyte, and electrolyte/ (Pt/ITO) interfaces were simulated using an RC parallel circuit, and the bulk materials, such as the Ti, ITO and conducting wire, were simulated using a series of resistors and inductors. The impedance of the bulk materials was simulated using L-0+R-0+R-b, the impedance of the working electrode was simulated using (C-1//R-1)//(R-a+(C-2//R-2), the electrolyte was simulated using C-3//R-3, and the counter electrode was simulated using C-4//R-4. (C) 2012 Elsevier Ltd and Techna Group Sri. All rights reserved.
Managerial efficiency in Taiwan bank branches: A network DEA
(2012-03-01)
Yang, Chyan
;
Liu, Hsian-Ming
;
經營管理研究所
;
Institute of Business and Management
Taiwan's banking industry remains highly fragmented and competitive after a series of financial liberalization and restructuring. With the enforcement of these fiscal policies, domestic banking institutions face a more dynamic, increasingly intense and highly competitive environment even as the banking industry's overall efficiency has gradually been enhanced. This structural change has further forced individual banking institutions, especially state-owned banks, to inspect the performance of their branches and identify improvement directions so as to gain further competitive advantages. To conduct a valid, fair and reliable evaluation on Taiwan's bank branches, we integrate a two-stage series performance model and fuzzy multiobjective model. A new scheme that considers the complementation of production and intermediation activities within a branch and overcomes the shortage of the traditional network DEA methodology about DMUs cannot be assessed on a common base. The results indicate that the overall performances of mixed ownership bank branches are superior to those of state-owned bank branches, representing that the advantages of banking privatization have some remedial effects for improving the managerial inefficiency of state-owned banks. In addition, the sensitivity analysis and decision-making matrix herein help bank management to identify branches' efficiency, weakness, and directions for improvement. (C) 2011 Elsevier B.V. All rights reserved.
Route-based data envelopment analysis models
(2012-03-01)
Chiou, Yu-Chiun
;
Lan, Lawrence W.
;
Yen, Barbara T. H.
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper proposes two novel route-based data envelopment analysis (DEA) models that jointly measure the route-level and company-level efficiencies amongst transport carriers. The core logics comprise a three-stage procedure that determines company efficiency, route efficiency and optimal allocation ratios for the common inputs. We prove that the ranking order of company performance determined by the route-based DEA model is identical to that determined by the company-based DEA model. An empirical case demonstrates the superiority of the proposed models in identifying the less efficient routs/companies as well as in reducing the input slacks without subjective conjectures. (C) 2011 Elsevier Ltd. All rights reserved.
Electron transport and electroluminescent efficiency of conjugated polymers
(2009-01-01)
Tseng, S. R.
;
Chen, Y. S.
;
Meng, H. F.
;
Lai, H. C.
;
Yeh, C. H.
The relation between charge balance and electroluminescent efficiency for polymers is studied systematically in this work. Light-emitting diodes of several kinds of polymers with very different efficiency are compared. The electron and hole currents are measured in the uni-polar devices and fitted by the theoretical model to get carrier mobilities. The universal features of the high efficiency polymers are that the electron and hole mobilities are comparable and the electron current is larger than the hole current due to the higher hole barriers. The electron current is more crucial than hole current to determine the efficiency in the bipolar light-emitting diode. The purity of polymers and low electron injection barriers both play significant roles in producing stronger electron currents. These results give the physical rules for designing new polymers and the device structures to achieve highly electroluminescent devices. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
Parallel Genetic Algorithm for Intelligent Model Parameter Extraction of Metal-Oxide-Semiconductor Field Effect Transistors
(2009)
Li, Yiming
;
電信工程研究所
;
Institute of Communications Engineering
Equivalent circuit model of semiconductor devices associated with a set of optimized parameters currently plays a central role in the circuit design and semiconductor manufacturing communities. An intelligent model parameter extraction system that simultaneously integrates evolutionary and numerical optimization techniques for optimal characterization of sub-100nm metal-oxide-semiconductor field effect transistors (MOSFETs) has recently been advanced [1]. In this article, to accelerate the extraction process, parallelization of the genetic algorithm (GA) for the intelligent model parameter extraction system of MOSFETs is developed. The GA implemented in the extraction system is mainly parallelized with a diffusion scheme on a PC-based Linux cluster with message passing interface libraries. Parallelization of GA is governed by various factors, which affect the quality of extracted parameters and its computational efficiency. The result obtained in this study shows that the diffusion GA is superior to an isolated GA, and the superiority of the diffusion GA becomes significant when the number of MOSFETs to be optimized is increased. Theoretical estimation and preliminary numerical implementation of parallel GA show that there exist an optimal number of processors with respect to the number of devices to be extracted. Benchmark results, such as speedup and efficiency including accuracy of extraction are presented and discussed for different sets of realistic multiple sub-100nm devices to show the robustness and efficiency of the method. Practical implementation of the parallel GA approach benefits the engineering of device model parameter extraction in nowadays semiconductor manufacturing industry.
Mathematical model of bypass behaviors used in scroll compressor
(2009-04-01)
Liu, Yangguang
;
Hung, Chinghua
;
Chang, Yuchoung
;
機械工程學系
;
Department of Mechanical Engineering
This paper has constructed a bypass mechanism mathematical model in scroll-type compressor (STC) and has been integrated into a simulation package to predict the STC performance. The bypass mechanism,when added to a fixed scroll, is used to prevent over-compression and liquid slugging. Under five specified operating conditions, it was found that the STC with the bypass action increased the isentropic efficiency 2.5-10% more than the STC without the bypass action. Meanwhile, the calculated results of the developed model have been validated by a STC testing apparatus. In addition, it was found that the design of the bypass mechanism in the paper, can completely avoid over-compression and pressure discrepancy while the STC is in operation. (C) 2008 Elsevier Ltd. All rights reserved.
Wideband tunable Gaussian-shaped spectral filters based on dispersion engineering
(2009-08-01)
Hsu, Kuei-Chu
;
Chen, Nan-Kuang
;
Chou, Sen-Yih
;
Liaw, Shien-Kuei
;
Lai, Yinchieh
Optical liquids can be used to engineer the dispersion characteristics of fibers by serving as the core or cladding to attain fundamental-mode cutoff effect. The short-/long-pass fiber filters are so made and concatenated to achieve widely thermo-optic tunable Gaussian-shaped spectral filters. The proposed wideband tunable Gaussian-shaped spectral filter provides a potential technique in application to high resolution bio-imaging. (C) 2009 Elsevier Inc. All rights reserved.
Numerical calculation of the reflectance of sub-wavelength structures on silicon nitride for solar cell application
(2009-10-01)
Sahoo, Kartika Chandra
;
Li, Yiming
;
Chang, Edward Yi
;
材料科學與工程學系
;
電子工程學系及電子研究所
In this study, we calculate the spectral reflectivity of pyramid-shaped silicon nitride (Si(3)N(4)) sub-wavelength structures (SWS). A multilayer rigorous coupled-wave approach is advanced to investigate the reflection properties of Si(3)N(4) SWS. We examine the simulation results for single layer antireflection (SLAR) and double layer antireflection (DLAR) coatings with SWS on Si(3)N(4) surface, taking into account effective reflectivity over a range of wavelengths and solar efficiency. The results Of Our study show that a lowest effective reflectivity of 1.77% can be obtained for the examined Si(3)N(4) SWS with the height of etched part of Si(3)N(4) and the thickness of non-etched layer of 150 and 70 rim, respectively, which is less than the results of an optimized 80 nm Si(3)N(4) SLAR (similar to 5.41%) and of an optimized DLAR with 80 nm Si(3)N(4) and 100 nm magnesium fluoride (similar to 5.39%). 1% cell efficiency increase is observed for the optimized Si solar cell with Si(3)N(4) SWS, compared with the cell with single layer Si(3)N(4) antireflection coatings (ARCs); furthermore, compared with DLAR coated solar cell, the increase is about 0.71%. The improvement on the cell efficiency is mainly due to lower reflectance Of Si(3)N(4) SWS over a wavelength region from 400 to 600 nm that leads to lower short circuit current. (C) 2009 Elsevier B.V. All rights reserved.

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