Browsing by Issue Date, starting with "2010-06-11"

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用於ＩＥＥＥ　８０２．１１無線區域網路之兩段式通話允諾控制演算法
(2010-06-11)
黃經堯
;
施雲懷
本發明係揭示一種用於IEEE 802.11無線區域網路之兩段式通話允諾控制演算法。此兩段式通話允諾控制演算法不僅能提高IEEE802.11無線區域網路系統的整體傳輸流量，更能使每一個在此系統中的使用者，均能得到一定的服務品質。 The present invention discloses a two－tier call admission control algorithm in IEEE 802.11 WLAN. The two－tier call admission control algorithm is given to improve the overall system throughput and guarantee the quality of service of every single user in the WLAN. 【創作特點】本發明之目的在於提供一種用於IEEE 802.11無線區域網路之兩段式通話允諾控制演算法，可用以改善整個系統之傳輸流量及保證每一使用者之服務品質。根據以上目的，將針對IEEE 802.11無線區域網路的實體層及媒介存取層進行分析，並檢視IEEE 802.11無線區域網的每一個模式在不同的頻道下所能達到的最大傳輸流量，且利用馬可夫鍊來導出連線速率自動調節演算法的數學模型。本發明提出一種用於IEEE 802.11無線區域網路之兩段式通話允諾控制演算法，該兩段式通話允諾演算法在IEEE 802.11無線區域網路中係用以允諾提供具有高品質服務要件之服務請求，此演算法包含以下步驟：使單一使用者及整個系統各自對應於一第一層測試及一第二層測試。由於本發明採用兩段式來處理使用者及系統之演算法，因此可改善整個系統之傳輸流量及保證每一使用者之服務品質。為讓本發明之上述和其他目的、特徵及優點能更明顯易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。
Engineered spin-state transitions of two interacting electrons in semiconductor nanowire quantum dots
(2010-06-11)
Chen, Yan-Ting
;
Cheng, Shun-Jen
;
Tang, Chi-Shung
;
電子物理學系
;
Department of Electrophysics
Spin properties of two interacting electrons in a quantum dot (QD) embedded in a nanowire with controlled aspect ratio and longitudinal magnetic fields are investigated by using a configuration-interaction (CI) method. The developed CI theory based on a three-dimensional parabolic model provides explicit formulations of the Coulomb matrix elements and allows for straightforward and efficient numerical implementation. Our studies reveal fruitful features of spin-singlet-triplet transitions of two electrons confined in a nanowire QD, as a consequence of the competing effects of geometry-controlled kinetic-energy quantization, Coulomb interaction, and spin-Zeeman energy. The developed theory is further employed to study various spin states of two quantum-confined electrons in the regime of "crossover" dimensionality, from quasi-two-dimensional (disklike) QDs to finite one-dimensional (rodlike) QDs.
Mobile-Taiwan experience in voice over IP-worldwide interoperability for microwave access trial
(2010-06-11)
Lin, Y. -B.
;
Sung, Y. -C.
;
Rashvand, H. F.
;
Liu, C. -L.
;
Liao, Y. -J.
Considering voice as a dominant telecommunication service, the performance of Voice over IP (VoIP) plays a critical role in deployment of worldwide interoperability for microwave access (WiMAX) technology providing all-IP network services. To that effect, in this study, the authors investigate the performance of a WiMAX-based VoIP established under the mobile Taiwan (M-Taiwan) field-trial funded program. To achieve the objectives of the trial the measurement results expressed in the form of mean opinion score (MOS), packet loss, packet delay and jitters. For the worst-case scenario, the tests were conducted under a stringent condition of both communicating devices, wirelessly connected to the same WiMAX base station under a heavy background traffic and interference, were experiencing simultaneous handovers during the communication. Upon their analysis, the field measurements confirm an excellent performance when both communicating devices kept stationary and show an acceptable quality for the service when both communicating devices are on the move at a speed of 50 km/h.
Cardiorespiratory phase synchronization during normal rest and inward-attention meditation
(2010-06-11)
Wu, Shr-Da
;
Lo, Pei-Chen
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Performance enhancement and analysis for IEEE 802.16e/m sleep mode operations with unsolicited grant service/real-time variable-rate connections
(2010-06-11)
Hsu, C. -H.
;
Feng, K. -T.
;
電機工程學系
;
Department of Electrical and Computer Engineering
The power saving class of type II (PSC II), one of the sleep mode operations in the IEEE 802.16e standard, is designed to reduce power consumption for unsolicited grant service (UGS) and real-time variable-rate (RT-VR) connections. However, the configuration of fixed-length listening windows in the PSC II incurs unnecessary energy consumption or packet loss for these types of connections. In order to enhance the performance of sleep mode operations, an approach with adaptive listening window (ALW) is proposed. The ALW scheme dynamically adjusts the length of each listening window based on the number of both arrival and retransmission packets as well as the delay constraint. Numerical analysis and simulation results show that the proposed ALW approach can effectively reduce the packet loss rate for UGS connections, whereas better energy conservation with reduced packet loss rate is achieved for RT-VR connections.
Effect of scattering on zero-bias anomaly and conductance reduction in quasi-one-dimensional quantum wires
(2010-06-11)
Liu, K. M.
;
Umansky, V.
;
Hsu, S. Y.
;
電子物理學系
;
Department of Electrophysics
We present a systematic study on the zero-bias conductance peak and its dependences on the carrier density and structural geometry in quasi-one-dimensional quantum wires (QWs). This zero-bias anomaly (ZBA) is suppressed by either decreasing the carrier density or increasing the QW length. The differential conductance at zero bias decreases with increasing temperature in accordance with a thermal-activation model up to a well-defined cut-off temperature. We demonstrate that the activation energy, cut-off temperature, and width of the ZBA are correlated, and suggest that these features are controlled by electron scattering in QWs.
Photocatalysis by Electron Transfer between Different-sized Anatases
(2010-06-15)
Ke, Tsung-Ying
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
;
應用化學系
;
Department of Applied Chemistry
In the solution state, photocatalysis of micro- and nano-sized anatases can be optimized at flat band and in a high pH solution, respectively. Furthermore, a remarkable photocatalyst that can be adopted over a wide range of pH values was produced by mixing commercial micro- and nano-sized anatases. Mixing causes the electron transfer between the identical phase but different-sized TiO(2) particles, subsequently separating the electrons and holes, as well as greatly facilitating photocatalysis. As is well known, the commercially available photocatalyst P25, a mixture of anatase and rutile, achieves a superior photocatalytic performance from pH 3 to 10, owing to the electron transfer between the various phases. This study elucidates these mixed photocatalysts, P25 and mixture of micro and nano-sized anatases. Crown Copyright (C) Published by Elsevier B.V. All rights reserved.
Degradation of carbofuran in aqueous solution by ultrasound and Fenton processes: Effect of system parameters and kinetic study
(2010-06-15)
Ma Ying-Shih
;
Sung Chi-Fanga
;
Lin Jih-Gaw
;
環境工程研究所
;
Institute of Environmental Engineering
To establish an efficient oxidation process for carbofuran degradation, the effects of some operating parameters such as dosages of H(2)O(2), Fe(2+) and initial carbofuran concentrations were observed during carbofuran degradation by the ultrasound process, Fenton process and a combined ultrasound/Fenton process. The degradation kinetics of carbofuran was also examined based on the experimental data. The results show that more than 99% of the carbofuran was degraded by the ultrasound/Fenton process within short reaction time periods. Increased dosages of H(2)O(2) and Fe(2+) enhanced the degradation of carbofuran in the ultrasound and Fenton oxidation processes, but initial carbofuran concentrations decreased carbofuran degradation in both the Fenton and ultrasound/Fenton processes. The degradation kinetics of carbofuran by the three oxidation processes was found to be in accordance with first-order reaction kinetics. The results provide fundamental information about the treatment of carbofuran wastewater and/or other pesticides by the ultrasound/Fenton oxidation process. (C) 2010 Elsevier B.V. All rights reserved.
Remarkable Photothermal Effect of Interband Excitation on Nanosecond Laser-Induced Reshaping and Size Reduction of Pseudospherical Gold Nanoparticles in Aqueous Solution
(2010-06-15)
Werner, Daniel
;
Hashimoto, Shuichi
;
Uwada, Takayuki
;
應用化學系
;
應用化學系分子科學碩博班
An in situ spectroscopic study of the nanosecond laser-induced melting and size reduction of pseudospherical gold nanoparticles with 54 +/- 7 nm diameter allowed the observation of a heating efficiency that was very dependent on the excitation wavelength. A remarkably greater efficiency was observed for the photothermal effect of interband excitation than that of intraband excitation. This noteworthy observation is ascribed to an altered electron heat capacity, c(e), during photoexcitation depending on the excitation energy, which is a phenomenon that has not been realized previously. As a result, a 60% reduction of the specific heat capacity, c(p), compared to that of bulk gold was obtained for interband excitation at 266 nm whereas the c(p) value for the excitation of the intraband transition at 532 nm was unaltered. A semiquantitative explanation was given for this striking phenomenon induced by interband excitation in which excitation relaxation cycles of electrons upon excitation of 5d electrons to the 6sp band lead to a reduced number of electrons contributing to the electron temperature rise in the vicinity of the Fermi level during the nanosecond laser pulse duration. By contrast, electronic-excitation within the 6sp band results in no net reduction in the number of electrons near the Fermi level, giving rise to a value of c(p) similar to that of bulk gold. Our finding that the heat capacity of gold nanoparticles can be changed upon UV laser excitation is important for understanding the fundamental nature of noble metal nanoparticles. Furthermore, this finding might be useful for preparing new metal alloy particles as well as for manipulating the thermodynamic properties of the nanoparticles.
Star Block Copolymers Through Nitroxide-Mediated Radical Polymerization From Polyhedral Oligomeric Silsesquioxane (POSS) Core
(2010-06-15)
Lu, Chu-Hua
;
Wang, Jui-Hsu
;
Chang, Feng-Chih
;
Kuo, Shiao-Wei
;
應用化學系
A series of star block copolymers were prepared through nitroxide-mediated radical polymerization (NMRP) from polyhedral oligomeric silsesquioxanes (POSS) nanoparticle by core-first polymerization. Eight N-alkoxyamine groups were incorporated onto the eight corners of a POSS cube through quantitative hydrosilylation through addition of octakis(dimethylsiloxy)silsesquioxane (O(8)M(8)(H) POSS) with 1-(2-(allyloxy)-1-phenylethoxy)-2,2,6,6-tetramethyl-piperidine (allyl-TEMPO) and Karstedt's agent (a platinum divinylsiloxane complex) was used as a catalyst. Octa-N-alkoxyamines POSS (OT-POSS) were used as platform to synthesize star polystyrene-POSS ((PS)(8)-POSS) homopolymer and diblock copolymers of poly(styrene-block-4-vinyl-pyridine)-POSS ((PS-b-P4VP)(8)-POSS) and poly(styrene-block-acetoxystyrene) ((PS-b-PAS)(8)-POSS) through NMRP. In addition, subsequent selective hydrolysis of the acetyl protective group of (PS-b-PAS)(8)-POSS, the poly(styrene-block-vinyl phenol) ((PS-b-PVPh)(8)-POSS) with strong hydrogen bonding group was obtained. The detailed chemical structure and self-assembled structures of these star block copolymers based on POSS were characterized by (1)H NMR, FTIR, SEC, TEM, and SAXS analyses.
Co-existence of anammox and denitrification for simultaneous nitrogen and carbon removal-Strategies and issues
(2010-06-15)
Kumar, Mathava
;
Lin, Jih-Gaw
;
環境工程研究所
;
Institute of Environmental Engineering
The discovery of anaerobic ammonium oxidation (anammox) has greatly improved the understanding of the nitrogen cycle. Anammox provides great promise for the removal of nitrogen from wastewater, containing high concentration of ammonium. However, the presence of organic carbon is considered as unfavorable to this autotrophic process, i.e. anammox. Most of the real wastewaters contain both organic carbon and nitrogen. Under this circumstance, several processes have been established primarily for the complete removal of organic carbon. Subsequently, the wastewater containing no or low organic carbon and nitrogen is treated via a variety of nitrogen removal processes. The co-existence of anammox and denitrification could be useful for the simultaneous removal of nitrogen and organic carbon in a single system rather than a sequential chain of treatment. This review addresses the microbiology, strategies, consequences and the future research challenges in the co-existence of anammox and denitrification. (C) 2010 Elsevier B.V. All rights reserved.
Unitary part of a contraction
(2010-06-15)
Gau, Hwa-Long
;
Wu, Pei Yuan
;
應用數學系
;
Department of Applied Mathematics
For a contraction A on a Hilbert space H, we define the index j(A) (resp.. k(A)) as the smallest nonnegative integer j (resp., k) such that ker(I - A(j)*A(j)) (resp., ker(I - A(k)*A(k)) boolean AND ker(I - A(k)*A(k)*)) equals the subspace of H on which the unitary part of A acts. We show that if n = dim H < infinity, then j(A) <= n (resp., k(A) <= left particularn/2left particular). and the equality holds if and only if A is of class S, (resp., one of the three conditions is true: (1) A is of class S, (2) n is even and A is completely nonunitary with parallel to A(n-2)parallel to = 1 and parallel to A(n-1)parallel to < 1. and (3) n is even and A = U circle times A', where U is unitary on a one-dimensional space and A' is of class S(n-1)). (C) 2010 Elsevier Inc. All rights reserved.
Dynamic manipulation and patterning of microparticles and cells by using TiOPc-based optoelectronic dielectrophoresis
(2010-06-15)
Yang, Shih-Mo
;
Yu, Tung-Ming
;
Huang, Hang-Ping
;
Ku, Meng-Yen
;
Hsu, Long
We develop light-driven optoelectronic tweezers based on the organic photoconductive material titanium oxide phthalocyanine. These tweezers function based on negative dielectrophoresis (nDEP). The dynamic manipulation of a single microparticle and cell patterning are demonstrated by using this light-driven optoelectronic DEP chip. The adaptive light patterns that drive the optoelectronic DEP onchip are designed by using Flash software to approach appropriate dynamic manipulation. This is also the first reported demonstration, to the best of our knowledge, for successfully patterning such delicate cells from human hepatocellular liver carcinoma cell line HepG2 by using any optoelectronic tweezers. (C) 2010 Optical Society of America
Leakage current cut-off device for ternary content addressable memory
(2010-06-15)
Huang
;
Po-Tsang
;
Liu
;
Wen-Yen
;
Hwang
A leakage current cut-off device for a ternary content addressable memory is provided. The storage cell of a ternary content addressable memory may be in the active mode, data-retention mode and cut-off mode. This invention applies a multi-mode data retention power gating device to the storage cell of the ternary content addressable memory to reduce the leakage current through the storage cell in the data-retention mode and the cut-off mode, and support the full speed operation in the active mode.
Study of InGaN-GaN Light-Emitting Diodes With Different Last Barrier Thicknesses
(2010-06-15)
Chen, Jun-Rong
;
Lu, Tien-Chang
;
Kuo, Hao-Chung
;
Fang, K. L.
;
Huang, K. F.
This work reports a theoretical and experimental study on the device performance of blue InGaN-GaN light-emitting diodes (LEDs) with different last barrier thicknesses. The experimental results show that the employment of a 25-nm-thick p-type GaN last barrier in GaN LEDs can improve the light output power from 35.6 to 40.2 mW at 50 mA. By using advanced device simulation, it is shown that the effective energy barrier created by the p-type AlGaN electron blocking layer (EBL) is significantly decreased due to the band bending at the interface between GaN last barrier and AlGaN EBL. The use of a p-type GaN last barrier before the growth of AlGaN EBL can provide a higher energy barrier to suppress the electron overflow and then enhance the light output power.
Effects of static magnetic fields on the development and aging of Caenorhabditis elegans
(2010-06-15)
Hung, Yao-Ching
;
Lee, Jia-Huey
;
Chen, Huang-Meng
;
Huang, Guewha Steven
;
材料科學與工程學系奈米科技碩博班
The current study investigated the possible effects of static magnetic fields (SMFs) on the developmental and aging processes of Caenorhabditis elegans. Nematodes were grown in the presence of SMFs of strengths varying from 0 to 200 mT. The rate of development and the lifespan were recorded. Treatment with a 200 mT SMF reduced the development time from the L2 to the L3 stage by 20%, from L3 to L4 by 23%, and from L4 to young adult by 31%. After SMF treatment, the average lifespan was reduced from 31 days to 24 days for wild-type nematodes. The up-regulation of clk-1, lim-7, daf-2, unc-3 and age-1 after SMF treatment was verified by quantitative real-time RT-PCR. Apparently, induction of gene expression is selective and dose dependent. The total developmental time was significantly reduced for the lin-4, lin-14, lin-41 and lim-7 mutants, but not for the let-7, clk-1, unc-3 and age-1 mutants. Lifespan analyses revealed that the let-7, unc-3 and age-1 mutants were not affected by SMF treatment. Here we show that SMFs accelerate nematode development and shorten nematode lifespan through pathways associated with let-7, clk-1, unc-3 and age-1.
有機光電元件
(2010-06-16)
孟心飛
;
洪勝富
;
曾信榮
;
李冠成
一種有機光電元件,包括第一電極;形成於該第一電極上之主動層;形成於該主動層上之第二中間層;以及形成於該第二中間層上之第二電極;其中,該第二中間層包括含有第二聚合物和第二有機小分子的第二混合物,且該第二有機小分子係選自電洞傳輸材料、電子傳輸材料、電子阻擋材料或電洞阻擋材料。本發明之有機光電元件係以溶液製程製備而得,具有製程簡便、改善薄膜成膜性和提升元件效率之優點。
自動棋譜產生系統及其方法
(2010-06-16)
莊仁輝
;
羅國華
;
許諾白
;
吳毅成
一種自動棋譜產生方法，找出攝影機所拍攝之棋盤影像中的棋子區域，並由棋盤影像判定是否有異動之棋子；並依照棋子的先後順序建立棋盤上所有棋子在影像中的位置相對關係，再藉由此位置相對關係資訊重建棋盤的座標系與各棋子之位置及思考時間，此自動棋譜產生方法可免除因需偵測棋盤格線所可能造成的困擾與誤差，並獲得一準確的電子棋譜。
重估一通道脈衝響應之方法、裝置及其電腦程式產品
(2010-06-16)
吳文榕
;
賴允仁
一種重估一通道脈衝響應之方法、裝置及電腦程式產品。該通道脈衝響應包含複數個通道切片,且對應至一通道頻率響應。該方法包含下列步驟:選取該等通道切片其中之一以作為一選定通道切片,其餘作為至少一待處理通道切片;扣除該至少一待處理通道切片對該通道頻率響應之影響,以得一第一通道頻率響應;以一最小平方法及該第一通道頻率響應,更新該選定通道切片;以及將該選定通道切片置換為更新後之該選定通道切片。藉此,可提高通道估測的準確度。
具色彩轉換層之有機電發光裝置
(2010-06-16)
張繼聖
;
劉柏村
;
陳金鑫
本發明係揭露一種具色彩轉換層之有機電發光裝置,其包含一有機電發光元件,其特徵在於係將有機電發光元件搭配一外部色彩轉換層(External color tuning layer)以形成白光有機發光裝置。本發明係將色彩轉換材料溶解於具有高透明度的PMMA溶液中,而後塗佈於有機電發光元件之出光面側以產生白光。此技術提供一簡化的方法以製作有機電發光裝置,並搭配一般多波段的白光有機電發光裝置,其具有一進一步降低操作電壓及提高功率效率之功用。