Browsing by Issue Date, starting with "2010-01-26"

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Method for power-efficient transmission supporting integrated services over wireless local area network
(2010-01-26)
Shih
;
Chih-Yung
;
Cheng
;
Ray-Guang
;
Chang
This invention provides a method for power-efficient transmission supporting integrated service over WLAN. The said invention combines the polling-based and the contention-based mechanisms, named on-demand polling (ODP). In the ODP scheme, a voice station is in the polling list when it is in the active mode. During the idle mode, it is configured to operate in the sleep mode for saving power. Also, it adopts the contention-based mechanism to join the list again while returning from the idle mode. On the other hand, the data station adopts the contention-based mechanism to transmit its packets over WLAN. In addition, to achieve service differentiation, the said invention also employs a prioritized access probability for voice over data services. Simulation results show that the said invention can reduce the power consumption for voice stations and enhance the throughput for data stations.
On Modulating the Phase Behavior of Block Copolymer/Homopolymer Blends via Hydrogen Bonding
(2010-01-26)
Chen, Shih-Chien
;
Kuo, Shiao-Wei
;
Jeng, U-Ser
;
Su, Chun-Jen
;
Chang, Feng-Chih
We have investigated the phase behavior or poly(4-vinylphenol-b-styrene) (PVPh-b-PS) when respectively blended with poly(4-vinylpyridine) (NVP), poly(methyl methacrylate) (PMMA), and PVPh homopolymers by mediated hydrogen bonding strengths with the PVPh block of the copolymer. The Fourier transform infrared spectroscopic result indicates that the PVPh-b-PS/P4VP blend has a much higher fraction (f(H)) of hydrogen-bonded PVPh blocks for it significantly higher miscibility compared with the blends with PMMA and PVPh homopolymers. Consequently, the PVPh-b-PS/P4VP blend, behaving as a neat diblock copolymer, exhibited a series of order-order phase transitions from the lamellar, gyroid, hexagonally packed cylinder to body-centered cubic structures when the P4VP content increases from 6 to 71% (volume fraction), as evidenced consistently by transmission electron microscopy and small-angle X-ray scattering. In contrast, both file PVPh-b-PS/PMMA and PVPh-b-PS/PVPh blends maintained essentially the lamellar structure upon a similar volume fraction increase in the homopolymers; the lamellar structure, however, was distorted to different extents at higher volume fractions of the additives, depending on the hydrogen bonding strength. On the basis of the results, the ratio of interassociation equilibrium constant (KA) over self-association equilibrium constant (K(B)), K(A)/K(B), is introduced as a convenient guide in estimating the phase behavior of similar polymer blends featuring hydrogen bonding interactions between file homopolymer additive and copolymer: with a K(A)/K(B) ratio much larger than unity, the blend system tends to behave as a neat copolymer; with a K(A)/K(B) ratio significantly smaller than unity, phase separation instead of order-order phase transitions call be expected for the blend above certain volume fraction of homopolymer additive.
Synthesis and Characterization of Bridged Bithiophene-Based Conjugated Polymers for Photovoltaic Applications: Acceptor Strength and Ternary Blends
(2010-01-26)
Chen, Chiu-Hsiang
;
Hsieh, Chao-Hsiang
;
Dubosc, Martin
;
Cheng, Yen-Ju
;
Su, Chain-Shu
Six of three-component donor-acceptor random copolymers P1-P6, symbolized as (thiophene donor)(m)-(thiophene acceptor)(n), were rationally designed and successfully synthesized by the palladium-catalyzed Stille Coupling, The 4H-cyclopenta[2, 1-b:3,4-b']dithiophene (CPDT) unit serves as the donor for P1-P4, while file benzothiadiazole (BT), quinoxaline (QU), dithienoquinoxaline, and thienopyrazine (TP) units are used as the acceptor for P1, P2, P3, and P4, respectively. P5 and P6 are structurally analogous to P1 and P2 except for using the dithieno[3.2-b:2',3'-d]silole (DTS) unit as the donor. Because the band gap lowering ability of the acceptor units in the polymer is in the order TP > BR > QU presumably due to the quinoid form Population in the polymers, the optical band gaps call be well adjusted to be 1.2, 1.6, and 1.8 eV for P4, P1, and P2, respectively. It is found that file two bridged bithiophene units, CPDT and DTS, have similar steric and electronic effects oil the P1 and P5 as well as P2 and P6, respectively, leading to comparable intrinsic properties and device performances. Bulk heterojunction photovoltaic cells based oil ITO/PEDOT:PSS/polymer:PC(71)BM/Ca/Al configuration were fabricated and characterized. Although P4 exhibits the lowest optical band gap, broadest absorption spectrum, and highest mobility, the too low-lying LUMO level hinders the efficient exciton dissociation, resulting in a low PCE of 0.7%. Compared with poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), random copolymer P1 shows more blue-shifted, broader absorption spectrum, comparable mobility, and a higher PCE of 2.0%. In view of the fact that P1 shows it higher band gap with strong absorption in visible region, while PCPDTBT-has a lower band gap to mainly absorb NIR light, a BHJ device with the active layer containing ternary blend of PCPDTBT/P(1)/PC(71)BM was investigated and achieved an enhanced PCE of 2.5%, which outperforms the devices based on the binary blending systems of PCPDTBT/PC7, BM (PCE = 1.4%) or P1/PC(71) BM (PCE = 2.0%,,) Linder the identical conditions. Such an improvement is ascribed to file complementary absorption and compatible structure of P1 and PCPDTBT polymers.
Anticancer and Antioxidant Activities of the Peptide Fraction from Algae Protein Waste
(2010-01-27)
Sheih, I-Chuan
;
Fang, Tony J.
;
Wu, Tung-Kung
;
Lin, Peng-Hsiang
;
生物科技學系
Algae protein waste is a byproduct during production of algae essence from Chlorella vulgaris. There is no known report on the anticancer peptides derived from the microalgae protein waste. In this paper, the peptide fraction isolated from pepsin hydrolysate of algae protein waste had strong dose-dependent antiproliferation and induced a post-G1 cell cycle arrest in AGS cells; however, no cytotoxicity was observed in WI-38 lung fibroblasts cells in vitro. The peptide fraction also revealed much better antioxidant activity toward peroxyl radicals and LDL than those of Trolox. Among these peptides, a potent antiproliferative, antioxidant, and NO-production-inhibiting hendecapeptide was isolated, and its amino acid sequence was VECYGPNRPQF. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce anticancer peptides.
WHITE-EMITTING PHOSPHORS AND LIGHTING APPARATUS USING THE SAME
(2010-01-28)
Chen, Teng-Ming
;
Chang, Chun-Kuei
A phosphor has a general formula of (M1-m-nCemEun)3Al2O5X2, wherein M is at least one selected from the group consisting of Ca, Sr and Ba; and X is at least one selected from the group consisting of Cl and Br, while 0
Covering graphs with matchings of fixed size
(2010-01-28)
Cariolaro, David
;
Fu, Hung-Lin
;
應用數學系
;
Department of Applied Mathematics
Let m be a positive integer and let G be a graph. We consider the question: can the edge set E(G) of G be expressed as the union of a set M of matchings of G each of which has size exactly m? If this happens, we say that G is [m]-coverable and we call M an [m]-covering of G. It is interesting to consider minimum [m]-coverings, i.e. [m]-coverings containing as few matchings as possible. Such [m]-coverings will be called excessive [m]-factolizations. The number of matchings in an excessive [m]-factorization is a graph parameter which will be called the excessive [m]-index and denoted by chi([m])'. In this paper we begin the study of this new parameter as well as of a number of other related graph parameters. (C) 2008 Elsevier B.V. All rights reserved.
Apparatus and method for forming multilayer polymer thin film
(2010-01-28)
Meng, Hsin-Fei
;
Horng, Sheng-Fu
;
Tseng, Hsin-Rong
;
Tuan, Chi-Shen
Apparatus and method for forming multilayer polymer thin film. The method uses a solution container with a gap to prevent the huge amount of solution from directly falling on the first layer. Then the wet film is formed by moving the container with the thin film thickness is decided by the distance between the gap and the substrate. The wet film is dried in a very short time by the heater therefore there is no time for the second solvent to dissolve the first layer. The method can effectively achieve the large-area and multilayer structure in organic devices through solution processing.
Elliptic equations in highly heterogeneous porous media
(2010-01-30)
Yeh, Li-Ming
;
應用數學系
;
Department of Applied Mathematics
Uniform estimate and convergence for highly heterogeneous elliptic equations are concerned. The domain considered consists of a connected fractured subregion (with high permeability) and a disconnected matrix block subregion (with low permeability). Let epsilon denote the size ratio of one matrix block to the whole domain and let the permeability ratio of the matrix block region to the fractured region be of the order epsilon(2). In the fractured region, uniform Holder and uniform Lipschitz estimates in epsilon of the elliptic solutions are derived; the convergence of the solutions in L(infinity) norm is obtained as well. Copyright (C) 2009 John Wiley & Sons, Ltd.
Improved crystal quality and performance of GaN-based light-emitting diodes by decreasing the slanted angle of patterned sapphire
(2010-02-01)
Cheng, Ji-Hao
;
Wu, YewChung Sermon
;
Liao, Wei-Chih
;
Lin, Bo-Wen
;
材料科學與工程學系
Periodic triangle pyramidal array patterned sapphire substrates (PSSs) with various slanted angles were fabricated by wet etching. It was found beside normal wurtzite GaN, zinc blende GaN was found on the sidewall surfaces of PSS. The crystal quality and performance of PSS-LEDs improved with decrease in slanted angle from 57.4 degrees to 31.6 degrees. This is because most of the growth of GaN was initiated from c-planes. As the growth time increased, GaN epilayers on the bottom c-plane covered these pyramids by lateral growth causing the threading dislocation to bend toward the pyramids.
Effect of Practice on Stepping Movements Onto Laterally Compliant Raised Structures: Age Differences in Healthy Males
(2010-02-01)
Yang, Bing-Shiang
;
Ashton-Miller, James A.
;
機械工程學系
;
Department of Mechanical Engineering
Objective: The aim of this study was to examine effects of practice and age on step-up movements onto raised structures. Background: Falls from laterally compliant structures, such as stepladders, often cause injuries in elderly persons. Although age differences in step-up movements onto raised structures with unexpected structural compliance have been reported, practice effects of such movement control have not been investigated. Method: Movement behavior of 20 healthy adults (10 young and 10 older males) was measured while they stepped up onto a raised structure with no compliance (i.e., rigid) (C(0)), a small amount of mediolateral compliance (C(1)), or greater mediolateral compliance (C(2)). The conditions C(0), C(1), and C(2) were presented in three sets of six fixed-order trials with step-up movements performed at a comfortable speed. Practice effects in step-up behavior were examined by comparing data within each trial block with the use of repeated-measures ANOVA. Results: Practice significantly reduced the stepping duration (Ts) needed to complete the step-up movement (p < .001). With practice, older males reduced their lateral oscillations 26% to 40% for C(1) and C(2), whereas the corresponding results for young males lay between 8% and 17%, respectively. The age difference in Ts decreased across six consecutive trials but remained significant, especially on the structure with greater compliance. Conclusion: With practice, both young and elderly men adapted their stepping behavior to the presence of lateral structural compliance, but it is noteworthy from a fall-injury prevention perspective that the elderly men required more trials to do so. Application: Designers and users of raised structures, such as stepladders, should be aware of the age difference of people using such structures and should minimize the structure compliance when designing them.
Ab Initio Chemical Kinetics for the NH(2) + HNO(x) Reactions, Part III: Kinetics and Mechanism for NH(2) + HONO(2)
(2010-02-01)
Xu, Shucheng
;
Lin, M. C.
;
應用化學系分子科學碩博班
;
Institute of Molecular science
The kinetics and mechanism for the reaction of NH(2) with HONO(2) have been investigated by ab initio calculations with rate constant prediction. The potential energy surface of this reaction has been computed by single-point calculations at the CCSD(T)/6311 +G(3df, 2p) level based on geometries optimized at the B3LYP/6-311 +G(3df, 2p) level. The reaction producing the primary products, NH(3) + NO(3), takes place via a precursor complex, H(2)N center dot center dot center dot HONO(2) with an 8.4-kcal/mol binding energy. The rate constants for major product channels in the temperature range 200-3000 K are predicted by variational transition state or variational Rice-Ramsperger-Kassel-Marcus theory. The results show that the reaction has a noticeable pressure dependence at T < 900 K. The total rate constants at 760 Torr Ar-pressure can be represented by k(total) = 1.71 x 10(-3) x T(-3.85) exp(-96/T) cm(3) molecule(-1) s(-1) at T = 200-550 K, 5.11 X 10(-23) x T(+3.22) exp(70/T) cm(3) molecule(-1) s(-1) at T = 550-3000 K. The branching ratios of primary channels at 760 Torr Ar-pressure are predicted: k(1) producing NH(3) + NO(3) accounts for 1,00-0,99 in the temperature range of 200-3000 K and k(2) + k(3) producing H(2)NO + HONO accounts for less than 0.01 when temperature is more than 2600 K. The reverse reaction, NH(3) + NO(3) -> NH(2) + HONO(2) shows relatively weak pressure dependence at P < 100 Torr and T < 600 K due to its precursor complex, NH(3)center dot center dot center dot O(3)N with a lower binding energy of 1.8 kcal/mol, The predicted rate constants can be represented by k(-1) = 6.70 x 10(-24) x T(+3.58) exp(-850/T) cm(3) molecule(-1) s(-1) at T = 200-3000 K and 760 Torr N(2) pressure, where the predicted rate at T = 298 K, 2.8 x 10(-16) cm(3) molecule(-1) s(-1) is in good agreement with the experimental data. The NH(3) + NO(3) formation rate constant was found to be a factor of 4 smaller than that of the reaction OH + HONO(2) producing the H(2)O + NO(3) because of the lower barrier for the transition state for the OH + HONO(2) (C) 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 69-78, 2010
絕對延遲時間產生裝置
(2010-02-01)
李鎮宜
;
游瑞元
;
余建螢
;
陳俊廷
一種絕對延遲時間產生裝置，由一製程供壓溫度(process-voltage-temperature；PVT)偵測裝置與一延遲時間產生器所構成。PVT偵測裝置包含複數組延遲模組與訊號相位/頻率控制模組，且各該延遲模組復包含對照單元與參照單元，此對照單元與參照單元在延遲特性上對PVT有相異的敏感度。各該延遲模組係用以比對原始訊號分別通過對照單元與參照單元所產生的相位或頻率差異，進而產生各該延遲模組的延遲參數，而訊號相位/頻率控制模組係用以接收並比對各該延遲參數，以標定該絕對延遲時間產生裝置的外部環境PVT狀態，進而控制與校正此延遲時間產生器，產生一精準的絕對延遲時間。透過上述絕對延遲時間產生裝置，受到不同的PVT(process-voltage-temperature)影響下，分析各該延遲模組的延遲參數，以標定當前PVT條件對該絕對延遲時間產生裝置造成的延遲情況，產生精準的絕對延遲時間，可進而產生精準頻率。在PVT改變的情況下，依然能夠保持穩定的準確度。
A Full duplex radio-over-fiber link with Multi-level OFDM signal via a single-electrode MZM and wavelength reuse with a RSOA
(2010-02-01)
Jiang, Wen-Jr
;
Lin, Chun-Ting
;
Shih, Po-Tsung
;
Chen, Jason (Jyehong)
;
Peng, Peng-Chun
This work demonstrates the feasibility of a full duplex Radio-over-fiber (RoF) link employing multi-level OFDM signal via a single-electrode Mach-Zehnder modulator and wavelength reuse for uplink utilizing a reflective semiconductor optical amplifier (RSOA). A High spectral efficiency 5-Gb/s 16-QAM OFDM signal with frequency multiplication for the RoF downstream link is demonstrated, and negligible penalty is achieved after 25-km standard single mode fiber transmission. Furthermore, wavelength reuse for a 1.25-Gb/s OOK signal via a RSOA for the upstream link is also demonstrated with a receiver penalty of less than 0.5 dB following 25-km SMF transmission. (C) 2010 Optical Society of America
用於通道解碼系統之候選人清單擴增裝置及其方法
(2010-02-01)
張錫嘉
;
廖彥欽
本發明係揭露一種可應用於多輸入多輸出通道解碼系統之候選人清單擴增裝置及其擴增方法。本發明所提出之路徑擴增方法可擴增候選人清單中之路徑以便於系統用於計算可靠度資訊,另一方面,本發明另提供一額外之校正項來動態補償可靠度資訊之準確度,進而大幅提昇多輸入多輸出系統之偵錯能力以及整體效能。
Scalar-tensor theory and the anisotropic perturbations of the inflationary universe
(2010-02-01)
Kao, W. F.
;
物理研究所
;
Institute of Physics
Inflationary higher derivative scalar-tensor theory is analyzed in this paper in a de Sitter background space. A useful model-independent formula of the Friedmann equation is derived and used to study the stability problem associated with the anisotropic perturbations of the inflationary solution. The stability conditions of the de Sitter solution are derived for a general class of models. For a simple demonstration, an induced gravity model is considered in this paper for the effects of the higher derivative interactions including a cubic term.
EFFICIENT VERIFIER-BASED AUTHENTICATED KEY AGREEMENT PROTOCOL FOR THREE PARTIES
(2010-02-01)
Wu, Tzong-Sun
;
Lin, Han-Yu
;
Hsu, Chien-Lung
;
Chang, Kuo-Yi
;
資訊工程學系
Authenticated key agreement protocols for three parties enable two clients to establish a secure communication channel through an authentication server. Generally speaking, there are two approaches to achieve this purpose. One is to issue a common session key for both clients by the key distribution center (KDC). The other is to use public key cryptosystems and the encrypted key exchange (EKE) protocol to encrypt the transmitted messages and then further derive a common session key. Recently, lots of researches on authenticated key agreement protocol for three parties use the servers public key to ensure the security of transmitted messages. Yet, the approach obviously has some drawbacks, such as increasing the cost of key management for each client. Hence, the demand for secure protocols without the server's public key comes out. In this paper, we propose an efficient verifier-based authenticated key agreement for three parties. The proposed protocol can resist the password guessing attack and other existential attacks. Moreover, compared with previous works, the proposed one also has lower computational costs.
Single-Longitudinal-Mode Erbium-Doped Fiber Laser with Novel Scheme Utilizing Fiber Bragg Grating inside Ring Cavity
(2010-02-01)
Yeh, C. H.
;
Chow, C. W.
;
光電工程學系
;
Department of Photonics
In this paper, we experimentally investigate a single-longitudinal-mode (SLM) S-band erbium-doped fiber (EDF) laser with dual-ring scheme using a S-band fiber Bragg grating (FBG) inside the gain cavity to restrict the lasing mode. The proposed laser is constructed by two-ring cavities serving as the mode filters. The FBG inside the proposed laser scheme can retrieve the SLM operation. Moreover, the output performance of the proposed fiber laser is also analyzed and discussed.
The monotone boundary property and the full coverage property of confidence intervals for a binomial proportion
(2010-02-01)
Wang, Hsiuying
;
交大名義發表
;
National Chiao Tung University
The methodology for deriving the exact confidence coefficient of some confidence intervals for a binomial proportion is proposed in Wang [2007. Exact confidence coefficients of confidence intervals for a binomial proportion. Statist. Sinica 17, 361-368]. The methodology requires two conditions of confidence intervals: the monotone boundary property and the full coverage property. In this paper, we show that for some confidence intervals of a binomial proportion, the two properties hold for any sample size. Based on results presented in this paper, the procedure in Wang [2007. Exact confidence coefficients of confidence intervals for a binomial proportion. Statist. Sinica 17, 361-368] can be directly used to calculate the exact confidence coefficients of these confidence intervals for any fixed sample size. (C) 2009 Elsevier B.V. All rights reserved.
Electrocatalytic activity of Pt nanoparticles electrodeposited on amorphous carbon-coated silicon nanocones
(2010-02-01)
Tiwari, Jitendra N.
;
Pan, Fu-Ming
;
Chen, Te-Ming
;
Tiwari, Rajanish N.
;
Lin, Kun-Lin
This study pulse-electrodeposits Pt nanoparticles on amorphous carbon-coated silicon nanocones (ACNCs) and explores them as the electrocatalyst for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) for direct methanol fuel cell applications. The work prepares silicon nanocones on the Si wafer using porous anodic aluminum oxide as the template and then deposits the amorphous carbon layer on the nanocones by microwave plasma chemical vapor deposition. According to Raman scattering and X-ray photoelectron spectroscopies (XPS), the surface of the ACNC support is composed of a nanocrystalline graphitic structure. and rich in oxygen-containing adspecies. The Pt nanoparticles pulse-electrodeposited on the highly ordered ACNC support disperses well with a large electrocatalytic surface area. The Pt/ACNC electrode exhibits excellent electrocatalytic activity and stability toward both MOR and ORR. This study suggests the abundant oxygen-containing surface species and the nanometer size of the Pt catalyst as the two major factors enhancing electrocatalytic performance of Pt/ACNC electrode. The XPS Study suggests the occurrence of charge transfer from pi-sites of the graphitic Structure to the Pt nanoparticle, thereby improving the electrochemical stability of the electrode. (C) 2009 Elsevier B.V. All rights reserved.
A unified model for detecting efficient and inefficient outliers in data envelopment analysis
(2010-02-01)
Chen, Wen-Chih
;
Johnson, Andrew L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Data envelopment analysis(DEA) uses extreme observations to identify superior performance, making it vulnerable to outliers. This paper develops a unified model to identify both efficient and inefficient outliers in DEA. Finding both types is important since many post analyses, after measuring efficiency, depend on the entire distribution of efficiency estimates. Thus, outliers that are distinguished by poor performance can significantly alter the results. Besides allowing the identification of outliers, the method described is consistent with a relaxed set of DEA axioms. Several examples demonstrate the need for identifying both efficient and inefficient outliers and the effectiveness of the proposed method. Applications of the model reveal that observations with low efficiency estimates are not necessarily outliers. In addition, a strategy to accelerate the computation is proposed that can apply to influential observation detection. (C) 2009 Elsevier Ltd. All rights reserved.