Browsing by Issue Date, starting with "2007-10-01"

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標誌輔助定位系統及方法
(2007-10-01)
吳至仁
;
蔡文祥
本發明係提供一種標誌輔助定位系統及方法,其係使用一固定於天花板上之圓形標誌,並以可擷取360度影像之全景影像擷取器攝取上方之圓形標誌影像,由於擷取到之標誌影像近似一橢圓形,可利用橢圓形的長軸及短軸等數値作為定位的計算參數,經過三角運算後即可得出目前所在位置。本發明的運算過程簡單,可加快定位速度,且圓形標誌從各個角度及方向均可偵測,更可避免外物干擾的情形發生。
Signal-to-Interference-Plus-Noise Ratio Analysis for Direct-Sequence Ultra-Wideband Systems in Generalized Saleh-Valenzuela Channels
(2007-10-01)
Wu, Wei-De
;
Lee, Cheng-Chia
;
Wang, Chung-Hsuan
;
Chao, Chi-chao
;
電信工程研究所
In this paper, exact signal-to-interference-plus-noise ratio (SINR) analysis of direct-sequence ultra-wideband (UWB) systems with Rake receiving in the presence of inter-symbol interference and multiple-access interference over a generalized Saleh-Valenzuela (GSV) channel with a generic pulse shaping function is provided. The SINR expression, for synchronized multiple-access, is first obtained without assuming random spreading. The GSV channel structure under consideration is a generalization of the Saleh-Valenzuela channel structure with generalized path-gain and path-arrival models, examples of which can include all the IEEE 802.15.3a UWB channel models and some of the IEEE 802.15.4a models. Then, by the novel treatment of renewal processes, the exact average SINR over the GSV channel statistics is obtained. Our analytical results well match computer simulations and can readily be applied to evaluate and improve the performance of UWB systems over realistic channel and interference models.
Analysing inaccurate artifact usages in workflow specifications
(2007-10-01)
Hsu, C. -L.
;
Wang, F. -J.
;
資訊工程學系
;
Department of Computer Science
Although many workflow models have been proposed, analyses on artifacts are seldom discussed. A workflow application with well structured and adequate resources may still fail or yield unexpected results in execution due to inaccurate artifact manipulation, for example, inconsistency between data flow and control flow, or contradictions between artifact operations. Thus, artifact analysis is very important since activities cannot be executed properly without accurate information. This paper presents a three-layer workflow model for designing a workflow and characterises the behaviour of an artifact by its state transition diagram. By abstracting common usages of artifacts, six types of inaccurate artifact usage affecting workflow execution are identified and a set of algorithms to detect these inaccurate usages in workflow specifications is presented. An example is demonstrated and then related works are compared.
Optical characteristics of silver film on the moth-eye structure
(2007-10-01)
Ting, C. J.
;
Tsai, H. Y.
;
Chou, C. P.
;
Lin, H. Y.
;
Wu, T. C.
The development of coating optics to lower the reflected light and thereby to increase the optical efficiency of an optical system has been a very important issue for many years. Conventional solutions to this, such as multilayered alternation of high and low refractive index layers, often lead to an expensive coating process. Recently, the use of antireflection structured (ARS) surface, which is called "moth-eye structure", has been proposed as an applicable option based on both the theoretical and experimental studies. In the current study, the experimental results of the reflectance and transmittance of two different thicknesses of silver films deposited on the moth-eye structure were carried out. The moth-eye structure arrays were fabricated by holographic exposure and photolithographic processes on the polymer film. The structure arrays were consisted of periodic length of about 300 nm, with the diameter of about 250 nm and the height of 150 nm. Compared with the silver coating film on the flat PET substrate, the optical property of the silver coating film on the moth-eye structure showed a better result for the anti-reflection application. The 25 nm-thick silver film on the moth-eye structure is suggested to be applied for the car window glass of antireflective films to obtain the high performance of heat insulation with acceptable transparency in the visible range.
A tracking motion approach for a piezotube actuator in a disk drive subject to disk deformation and disturbance
(2007-10-01)
Chang, C. S.
;
Liu, T. S.
;
Tang, Y. C.
;
機械工程學系
;
Department of Mechanical Engineering
This study investigates the disk drive dynamics when a disk surface deforms and a disturbance force is exerted on a pickup head in near-field optical disk drives. Serving as an actuator, a piezotube is connected to the suspension of the pickup head. A model is constructed to investigate the pickup head dynamics. Equations of motion for focusing and track-following are derived in the presence of disk surface deformation and the disturbance force on the pickup head. A proportional and derivative control method is carried out in numerical examples. There exists a critical proportional gain that influences the number of resonances in the frequency spectra. Numerical results show that there is only one resonance or none in the frequency spectra when the proportional gain is larger than the critical proportional gain. Hence, the tracking error ratio becomes smaller than one within a wide frequency range, if few resonances appear in the frequency spectra.
Performance analysis of IEEE 802.11 DCF in a multi-rate WLAN
(2007-10-01)
Chu, Weikuo
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
The IEEE 802.11 family of specifications is by far the most prominent and successful technique for accessing WLANs. Because the channel used by wireless devices is a time-varying broadcast medium, these devices need to have multi-rate and rate-adaptive capability to adapt to the changing channel so that better performance can be achieved. In this paper, we propose an analytical model, which we call Rate-Adaptive Markov Chains, to study the saturation throughput and delay performance of an 802.11 WLAN in which the mobile hosts have multi-rate support, will use the ARF protocol to adapt rates for different channel qualities, and follow the DCF protocol to contend for data transmissions in a slowly-varying channel. Simulation results are also provided to verify the correctness of the model.
Untitled
(2007-10-01)
Chang, Gerard J.
;
Fu, Hung-Lin
;
Zhu, Xuding
;
應用數學系
;
Department of Applied Mathematics
Estimating and testing process precision with presence of gauge measurement errors
(2007-10-01)
Pearn, W. L.
;
Liao, Mou-Yuan
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process capability indices have been widely used in the manufacturing industry. Those capability indices, quantifying process potential and performance, are important for any successful quality improvement activities and quality program implementation. Because of the simplicity and easy of understanding, the precision index C-p has gained its popularity for measuring process consistency. However, the quality of data on the process characteristics relies very much on the gauge measurement. Conclusions about capability of the process just only based on the single numerical value of the index are not reliable. In this paper, we not only conduct the performance of the index C-p with gauge measurement errors, but also present adjusted confidence interval bounds and critical values for capability testing purpose of C-p with unavoidable measurement errors. Our research would help practitioners to determine whether the factory processes meet the capability requirement, and make more reliable decisions.
A Petri-Net approach to modular supervision with conflict resolution for semiconductor manufacturing systems
(2007-10-01)
Lee, Jin Shyan
;
Zhou, MengChu
;
Hsu, Pau Lo
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In a semiconductor manufacturing system, particular human operations may violate desired requirements and lead to destructive failure. For such human-in-the-loop systems, this paper proposes a supervisory framework which guarantees that manual operations meet required specifications so as to prevent human errors in operation using Petri nets. Moreover, a modular technique with an intersection mechanism is proposed in order to cope with the state-space explosion problem of large-scale systems. A rapid thermal process in semiconductor manufacturing systems is provided to show the practicability of the proposed approach.
Modified perfectly matched layer conductivity profile for the alternating direction implicit finite-difference time-domain method with split-field perfectly matched layer
(2007-10-01)
Hwang, J. -N.
;
Chen, F. -C.
;
電信工程研究所
;
Institute of Communications Engineering
The modified perfectly matched layer (PML) conductivity profiles are proposed to improve the stability of the alternating direction implicit (ADI) finite-difference time-domain (FDTD) method with a split-field PML absorber. The amplification matrix of this scheme is derived based on the Von Neumann method. From the stability analysis, it is found that this scheme is unstable at the PML interface and inside the PML regions. The instability of this scheme inside the PML regions can be improved with the modified PML conductivity profile. The theoretical results are validated by means of numerical simulations.
風險性資本與銀行效率之分析
(2007-10-01)
陳玉涓
;
邱永和
;
Yu-Chuan Chen
;
Yung-Ho Chiu
;
Institute of Business and Management
本文以Basel Ⅱ的風險性應計提資本(Risk-Based Capital Requirement)及最低資本適足要求(Minimal Capital Adequacy Requirement)，作為衡量銀行風險的客觀指標，並利用本指標估算考量風險下之金融機構效率。本文研究樣本為29家本國商業銀行，研究期間為民國91年至民國93年。本研究第一階段採用Basel Ⅱ之標準法，並利用各銀行公佈之資本適足率，估算本國銀行之信用風險、市場風險、作業風險、及調整後資本適足率，以作為第二階段效率分析之風險投入變數；第二階段則利用資料包絡法、修正的資料包絡法、及差額變數基礎之超效率評估模型，解決效率值排名問題，並估算經風險調整前、後之本國銀行效率，而後討論本國銀行之規模效率及影響效率表現之因子。本文實證結果顯示：(1)市場風險應計提資本有逐年上升的趨勢；而信用風險佔總風險性資產比率逐年下降。(2)經風險調整後之本國銀行效率值高於調整前之本國銀行效率值。(3)低風險銀行之平均效率值高於高風險銀行之平均效率值。(4)本國商業銀行已無法依靠傳統的放款業務支撐其生存，應多致力於傳統銀行業務外之其他營業收入擴展，且積極的進行風險管理。
在操演與不操演之間：看被囚少年的影像實踐
(國立陽明交通大學出版社, 2007-10-01)
游靜
我在2002至2005年間先後在澳門、日本北海道及香港的少年監獄（或稱「感化院」、「教導所」、「男、女童院」等）舉行媒體工作坊，教導12至16歲的被囚少年攝影、錄音及拍攝錄像的技巧。本文首先討論國家機器把犯罪少年同時進行身體與資訊上的隔離，製造出強化這些少年持續處於「偏差」狀態的效果，探討美國、日本及香港不少社會與心理學家、社工對犯罪少年的研究與「青年論述」，如何加深了主流社會對「偏差少年」、「邊緣少年」的定見，加強警治(policing)的認受性。本文透過就日本與香港同學的影像作品作文本分析，從而瞥見論述與創作實踐之間互動的可能性，企圖藉此探索工作坊的介入（包括事前斟商的過程）與同學的創作，如何對攝影這媒體長期被國家機器挪用來界定、製造及操控「偏差性」的歷史功能作出回應，顛覆被客觀數據化的位置。我希望能借助本文，透過對影像的詮釋與論述策略，為這些建立中的主體構成過程提供更多閱讀及被充權的可能性，重新肯定從青年主體出發的重要性，尤其是被認為「犯罪」、「偏差」、「邊緣」、「問題製造者」。最後，以性別研究學者巴特勒的性別操演概念及人類學家德格拉斯解讀的部落「除罪化」儀式，與被囚少年創作的影像互讀，提出審視切合在地脈絡的、「不操演」的正典效果的需要，及操演雙重偏差性的表述可能，並挪用學者清水晶子對日本酷兒主體生存策略的另類詰問，重新思考把「偏差」欲望，以「不知廉恥的曖昧宣稱」形態操演出來的可能性與意義。
ISPMER: Integrated system for combined PET, MRI, and electrophysiological recording in somatosensory studies in rats
(2007-10-01)
Shih, Yen-Yu
;
Chen, You-Yin
;
Chen, Jyh-Cheng
;
Chang, Chen
;
Jaw, Fu-Shan
The present study developed an integrated system for use in combined PET, MRI, and electrophysiological recording in somatosensory studies in rats, called ISPMER. A stereotaxic frame was designed for animal positioning that could be used in all three measurement modalities, and its dimensions complied with the gold standard of the Paxinos and Watson rat brain atlas. A graphical user interface was developed for analyzing the data using several signal processing algorithms. This integrated system provides a novel interface for the recording and processing of three-dimensional neuronal signals in three modalities. (c) 2007 Elsevier B.V. All rights reserved.
Motion flow-based video retrieval
(2007-10-01)
Su, Chih-Wen
;
Liao, Hong-Yuan Mark
;
Tyan, Hsiao-Rong
;
Lin, Chia-Wen
;
Chen, Duan-Yu
In this paper, we propose the use of motion vectors embedded in MPEG bitstreams to generate so-called "motion flows", which are applied to perform video retrieval. By using the motion vectors directly, we do not need to consider the shape of a moving object and its corresponding trajectory. Instead, we simply "link" the local motion vectors across consecutive video frames to form motion flows, which are then recorded and stored in a video database. In the video retrieval phase, we propose a new matching strategy to execute the video retrieval task. Motions that do not belong to the mainstream motion flows are filtered out by our proposed algorithm. The retrieval process can be triggered by query-by-sketch or query-by-example. The experiment results show that our method is indeed superb in the video retrieval process.
影像對比加強方法
(2007-10-01)
任慈澄
;
王聖智
;
謝曜任
本發明提出一種影像對比加強方法，掃瞄一張影像以依序計算影像中相鄰兩像素亮度差異之值，接著判斷此值是否大於預設之一門檻值，若是，則根據此兩亮度值產生一正向力序列，若否，則產生一負向力序列，正向力序列和負向力序列的產生及累加運算將一直重複運作得到淨正向力序列及淨負向力序列，直到判斷結束，接著將淨正向力序列減去加上權重的淨負向力序列而成為一淨力序列，並積分且正規化，以得到一擴張力函數與原始亮度轉換函數做線性組合，而得到一新的亮度轉換函數去調整原始影像的亮度值，以加強影像對比。另外本發明還提出兩種不同形式的力序列(形式一和形式二)，若以此力序列作為對比加強，則可省去計算負向力序列所需之成本。本發明還可同時避免雜訊放大及影像不自然。
Growth enhancement and field emission characteristics of one-dimensional 3,4,9,10-perylenetetracarboxylic dianhydride nanostructures on pillared titanium substrate
(2007-10-01)
Suen, Shich-Chang
;
Whang, Wha-Tzong
;
Hou, Fu-Ju
;
Dai, Bau-Tong
;
材料科學與工程學系
We have utilized the pi-pi interactions between 3,4,9, 1 0-perylenetetracarboxylic dianhydride (PTCDA) molecules and temperature-induced morphology changes to synthesize one-dimensional (ID) nanostructures of PTCDA on a heated (ca. 100 degrees C) titanium substrate through vacuum sublimation. Because of the pillared Ti structures and the presence of reactive Ti-Cl sites, the titanium substrate played a crucial role in assisting the PTCDA molecules to form ID nanostructures. The average diameter of the nanofibers deposited on the Ti-CVD substrate, a Ti substrate formed by chemical vapor deposition (CVD), at 100 degrees C was ca. 84 run, with lengths ranging from 100 nm to 3 mu m. When the PTCDA nanofibers were biased under vacuum, the emission current remained stable. The turn-on electric field for producing a current density of 10 mu A/cm(2) was 8 V/mu m. The maximum emission current density was 1.3 mA/cm(2), measured at 1100 V (E = 11 V/mu m). From the slope of the straight line obtained after plotting ln(J/E-2) versus 1/E, we calculated the field enhancement factor beta to be ca. 989. These results demonstrate the PTCDA nanofibers have great potential for applicability in organic electron-emitting devices. (C) 2007 Elsevier B.V. All rights reserved.
Relieving hot-spot temperature during electromigration in solder and current crowding effects bumps by using Cu columns
(2007-10-01)
Liang, S. W.
;
Chang, Y. W.
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Solder joints with Cu columns appear to be one of the best structures to resist electromigration. Three-dimensional thermoelectrical analysis was employed to simulate the current density and temperature distributions for eutectic SnPb solder bumps with 0.5, 5, 25, 50, and 100 mu m Cu under bump metallization (UBM). It was found that the hot spots and current crowding effects in the solder were reduced significantly when the Cu thickness was over 50 Pm, whereas the overall Joule heating effect remained almost unchanged. The mechanism by which the Cu column is effective in relieving the hot spot and current crowding effects is to keep the solder away from the heat source and crowding region. Simulated at a current of 0.6 A and 70 degrees C, the estimated mean time to failure of the joints with a 50-mu m-thick Cu column was 6.7 times longer than that of joints with a 0.5-mu m-thick Cu UBM.
Thermoelastic coupled modeling for a thermal bimorph actuator
(2007-10-01)
Wu, Liang-Chieh
;
Chang, Kow-Ming
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper presents a theoretical thermoelastic coupled model for a thermal bimorph actuator driven by a harmonically varying thermal load in micro-electro-mechanical systems. The thermoelastic coupling, which arises from the coupling of the strain rate to the temperature field of the heat transport, is considered in this model. The frequency responses are simulated using the theorem of eigenmode expansion. The effects of thermoelastic coupling on the resonant frequency and the quality factor Q for each eigenmode resonance of the deflection are calculated and compared with the same effects resulted from air damping. It shows that for the example of an aluminum-polysilicon thermal bimorph actuator, the resonant frequencies are generally shifted downward with the order larger than that of air damping, whereas the influence of thermoelastic coupling on the Q is more significant than that of air damping under high vacuum level. (c) 2007 Elsevier Ltd. All rights reserved.
A 65-fJ/conversion-step 0.9-V 200-kS/s rail-to-rail 8-bit successive approximation ADC
(2007-10-01)
Hong, Hao-Chiao
;
Lee, Guo-Ming
;
電控工程研究所
;
Institute of Electrical and Control Engineering
An 8-bit successive approximation (SA) analog-to-digital converter (ADC) in 0.18 mu m CMOS dedicated for energy-limited applications is presented. The SA ADC achieves a wide effective resolution bandwidth (ERBW) by applying only one bootstrapped switch, thereby preserving the desired low power characteristic. Measurement results show that at a supply voltage of 0.9 V and an output rate of 200 kS/s, the SA ADC performs a peak signal-to-noise-and-distortion ratio of 47.4 dB and an ERBW up to its Nyquist bandwidth (100 kHz). It consumes 2.47 mu W in the test, corresponding to a figure of merit of 65 fJ/conversion-step.
Engineering the bandgap of a two-dimensional photonic crystal with slender dielectric veins
(2007-10-01)
Liu, Wen-Long
;
Yang, Tzong-Jer
;
電子物理學系
;
Department of Electrophysics
This study proposes the double-hybrid-rods structure of two-dimensional (2D) photonic crystals of a square lattice. A square dielectric rod connected with slender rectangular dielectric veins on the middle of each side,of dielectric square rod. Some specific modes are found to be sensitive to certain structural parameters, such as the length, the dielectric constant and the shift of the position of the veins, etc., and giving rise to a new complete PBG at lower index bands. These results could be understood by the use of band structure point of view. In particular, by carefully adjusting the structural parameters, the band structure of the photonic crystal can be substantially engineered to achieve large bandgaps. (C) 2007 Elsevier B.V.. All rights reserved.