Browsing by Issue Date, starting with "2008-08-15"

Now showing 1 - 20 of 54848

Compact dimension of denatured states of staphylococcal nuclease
(2008-08-15)
Chow, C. -Y.
;
Wu, Ming-Chya
;
Fang, Huey-Jen
;
Hu, Chin-Kun
;
Chen, Hueih-Min
Fluorescence and circular dichroism stopped-flow have been widely used to determine the kinetics of protein folding including folding rates and possible folding pathways. Yet, these measurements are not able to provide spatial information of protein folding/unfolding. Especially, conformations of denatured states cannot be elaborated in detail. In this study, we apply the method of fluorescence energy transfer with a stopped-flow technique to study global structural changes of the staphylococcal nuclease (SNase) mutant K45C, where lysine 45 is replaced by cysteine, during folding and unfolding. By labeling the thiol group of cysteine with TNB (5,5 '-dithiobis-2-nitrobenzoic acid) as an energy acceptor and the tryptophan at position 140 as a donor, distance changes between the acceptor and the donor during folding and unfolding are measured from the efficiency of energy transfer. Results indicate that the denatured states of SNase are highly compact regardless of how the denatured states (pH-induced or GdmCl-induced) are induced. The range of distance changes between two probes is between 25.6 and 25.4 angstrom while it is 20.4 angstrom for the native state. Furthermore, the folding process consists of three kinetic phases while the unfolding process is a single phase. These observations agree with our previous sequential model. No reversible arrow D-1 reversible arrow D-2 reversible arrow D-3 (Chen et al., J Mol Biol 1991;220:771-778). The efficiency of protein folding may be attributed to initiating the folding process from these compact denatured structures.
Global distributions and occurrence rates of transient luminous events
(2008-08-15)
Chen, Alfred B.
;
Kuo, Cheng-Ling
;
Lee, Yi-Jen
;
Su, Han-Tzong
;
Hsu, Rue-Ron
We report the global transient luminous event (TLE) distributions and rates based on the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) experiment onboard the FORMOSAT-2 satellite. ISUAL observations cover 45 degrees S to 25 degrees N latitude during the northern summer and 25 degrees S to 45 degrees N latitude during the northern winter. From July 2004 to June 2007, ISUAL recorded 5,434 elves, 633 sprites, 657 halos, and 13 gigantic jets. Surprisingly, elve is the dominant type of TLEs, while sprites/halos are a distant second. Elve occurrence rate jumps as the sea surface temperature exceeds 26 degrees Celsius, manifesting an ocean-atmosphere-ionosphere coupling. In the ISUAL survey, elves concentrate over the Caribbean Sea, South China Sea, east Indian Ocean, central Pacific Ocean, west Atlantic Ocean, and southwest Pacific Ocean; while sprites congregate over central Africa, Japan Sea, and west Atlantic Ocean. The ISUAL experiment observed global rates of 3.23, 0.50, 0.39, and 0.01 events per minute for elves, sprites, halos, and gigantic jets, respectively. Taking the instrumental detection sensitivity and the restricted survey area into account, the corrected global occurrence rates for sprites and elves likely are a factor of two and an order of magnitude higher, respectively. ISUAL observations also indicate that the relative frequency of high peak current lightning (> 80 kA) is 10 times higher over the oceans than over the land. On the basis of the corrected ISUAL elve global occurrence rate, the total electron content at the lower ionosphere above elve hot zones was computed to be elevated by more than 5%.
Obtaining the steady-state drawdown solutions of constant-head and constant-flux tests
(2008-08-15)
Wang, Chih-Tse
;
Yeh, Hund-Der
;
環境工程研究所
;
Institute of Environmental Engineering
The solutions of constant-head and sonstant-flux tests are commonly used to predict the temporal or spatial drawdown distribution or to determine aquifer parameters. Theis and Thiem equations, for instance, are well-known transient and steady-state drawdown solutions, respectively, of the constant-flux test. It is known that the Theis equation is not applicable to the case where the aquifer has a finite boundary or the pumping time tends to infinity. On the other hand, the Thiem equation does not apply to the case where the aquifer boundary is infinite. However. the issue of obtaining the Thiem equation from the transient drawdown solution has not previously been addressed. In this paper, the drawdown solutions for constant-head and constant-flux tests conducted in finite or infinite confined aquifers with or without consideration of the effect of the well radius are examined comprehensively. Mathematical verification and physical interpretation of the solutions to these two tests converging or not converging to the Thiem equation are presented. The result shows that there are some finite-domam solutions for these two tests that can converge to the Thiem equation when the time becomes infinitely large. In addition, the time criteria to give a good approximation to the finite-domain solution by the infinite-domain solution and the Thiem equation are investigated and presented. Copyright (C) 2008 John Wiley & Sons, Ltd.
Information granulation based data mining approach for classifying imbalanced data
(2008-08-15)
Chen, Mu-Chen
;
Chen, Long-Sheng
;
Hsu, Chun-Chin
;
Zeng, Wei-Rong
;
運輸與物流管理系註：原交通所+運管所
Recently, the class imbalance problem has attracted much attention from researchers in the field of data mining. When learning from imbalanced data in which most examples are labeled as one class and only few belong to another class, traditional data mining approaches do not have a good ability to predict the crucial minority instances. Unfortunately, many real world data sets like health examination, inspection, credit fraud detection, spam identification and text mining all are faced with this situation. In this study, we present a novel model called the "Information Granulation Based Data Mining Approach" to tackle this problem. The proposed methodology, which imitates the human ability to process information, acquires knowledge from Information Granules rather then from numerical data. This method also introduces a Latent Semantic Indexing based feature extraction tool by using Singular Value Decomposition, to dramatically reduce the data dimensions. In addition, several data sets from the UCI Machine Learning Repository are employed to demonstrate the effectiveness of our method. Experimental results show that our method can significantly increase the ability of classifying imbalanced data. (c) 2008 Elsevier Inc. All rights reserved.
Magnetic ground state and transition of a quantum multiferroic LiCu(2)O(2)
(2008-08-15)
Huang, S. W.
;
Huang, D. J.
;
Okamoto, J.
;
Mou, C. Y.
;
Wu, W. B.
Based on resonant soft x-ray magnetic scattering, we report that LiCu(2)O(2) exhibits a large interchain coupling which suppresses quantum fluctuations along spin chains, and a quasi-2D short-range magnetic order prevails at temperatures above the magnetic transition. These observations unravel the fact that the ground state of LiCu(2)O(2) possesses long-range 2D-like incommensurate magnetic order rather than being a gapped spin liquid as expected from the nature of quantum spin-1/2 chains. In addition, the spin coupling along the c axis is found to be essential for inducing electric polarization.
Deriving protein dynamical properties from weighted protein contact number
(2008-08-15)
Lin, Chih-Peng
;
Huang, Shao-Wei
;
Lai, Yan-Long
;
Yen, Shih-Chung
;
Shih, Chien-Hua
It has recently been shown that in proteins the atomic mean-square displacement (or B-factor) can be related to the number of the neighboring atoms (or protein contact number), and that this relationship allows one to compute the B-factor profiles directly from protein contact number. This method, referred to as the protein contact model, is appealing, since it requires neither trajectory integration nor matrix diagonalization. As a result, the protein contact model can be applied to very large proteins and can be implemented as a high-throughput computational toot to compute atomic fluctuations in proteins. Here, we show that this relationship can be further refined to that between the atomic mean-square displacement and the weighted protein contact-number, the weight being the square of the reciprocal distance between the contacting pair. In addition, we show that this relationship can be utilized to compute the cross-correlation of atomic motion (the B-factor is essentially the auto-correlation of atomic motion). For a nonhomologous dataset comprising 972 high-resolution X-ray protein structures (resolution < 2.0 angstrom and sequence identity < 25%), the mean correlation coefficient between the X-ray and computed B-factors based on the weighted protein contact-number model is 0.61, which is better than those of the original contact-number model (0.51) and other methods. We also show that the computed correlation maps based on the weighted contact-number model are globally similar to those computed through normal model analysis for some selected cases. Our results underscore the relationship between protein dynamics and protein packing. We believe that our method will be useful in the study of the protein structure-dynamics relationship.
PhosphoPOINT: a comprehensive human kinase interactome and phospho-protein database
(2008-08-15)
Yang, Chia-Ying
;
Chang, Chao-Hui
;
Yu, Ya-Ling
;
Lin, Tsu-Chun Emma
;
Lee, Sheng-An
Motivation: To fully understand how a protein kinase regulates biological processes, it is imperative to first identify its substrate(s) and interacting protein(s). However, of the 518 known human serine/threonine/tyrosine kinases, 35 of these have known substrates, while 14 of the kinases have identified substrate recognition motifs. In contrast, 85 of the kinases have protein-protein interaction (PPI) datasets, raising the possibility that we might reveal potential kinase-substrate pairs from these PPIs. Results: PhosphoPOINT, a comprehensive human kinase interactome and phospho-protein database, is a collection of 4195 phospho-proteins with a total of 15 738 phosphorylation sites. PhosphoPOINT annotates the interactions among kinases, with their down-stream substrates and with interacting (phospho)-proteins to modulate the kinase-substrate pairs. PhosphoPOINT implements various gene expression profiles and Gene Ontology cellular component information to evaluate each kinase and their interacting (phospho)-proteins/substrates. Integration of cSNPs that cause amino acids change with the proteins with the phosphoprotein dataset reveals that 64 phosphorylation sites result in a disease phenotypes when changed; the linked phenotypes include schizophrenia and hypertension. PhosphoPOINT also provides a search function for all phospho-peptides using about 300 known kinase/phosphatase substrate/binding motifs. Altogether, PhosphoPOINT provides robust annotation for kinases, their downstream substrates and their interaction (phospho)-proteins and this should accelerate the functional characterization of kinomemediated signaling.
具有雙臨界電壓的邏輯閘電路及其應用之標準元件庫
(2008-08-16)
周世傑
;
邱奕偉
;
胡嘉琳
本發明係揭露一種具有雙臨界電壓的邏輯閘電路及其應用之標準元件庫。藉由在一邏輯電路之關鍵路徑上使用至少一個具有雙臨界電壓的邏輯閘電路,其包括至少二個電晶體,且在此等電晶體中之靠近電壓源的電晶體係採用臨界電壓較低的電晶體,其餘電晶體則係採用臨界電壓相對較高的電晶體,如此即可降低寄生電容値,進而降低動態功率的消耗,使得總體功率降低。
有限場除法器架構之實現方法
(2008-08-16)
吳昭逸
;
張錫嘉
本發明是關於一種有限場除法器架構之實現方法。藉由將所有的除法器標準基礎輸入轉換到合成域,在這個網域下用子域的乘法器,平方器,加法器,查表來完成電路,而之後再將其從合成域轉換回標準基礎的有限體下。使用者可以在一個時脈週其下完成除法運算,並且達到低複雜度的須求。在許多有限場的運算上,支援這樣的除法電路是相當有幫助的,例如解RS/BCH碼或是ECC/Security處理器的應用。
Embedding hamiltonian paths in hypercubes with a required vertex in a fixed position
(2008-08-16)
Lee, Chung-Meng
;
Tan, Jimmy J. M.
;
Hsu, Lih-Hsing
;
資訊工程學系
;
Department of Computer Science
Assume that n is a positive integer with n >= 2. It is proved that between any two different vertices x and y of Q(n) there exists a path PI(x, y) of length l for any l with h(x, y) <= l <= 2(n) - 1 and 2 vertical bar(l - h(x, y)). We expect such path P-l(x, y) can be further extended by including the vertices not in P-l(x, y) into a hamiltonian path from x to a fixed vertex z or a hamiltonian cycle. In this paper, we prove that for any two vertices x and z from different partite set of n-dimensional hypercube Q(n), for any vertex y is an element of V(Q(n)) - {x, z}, and for any integer I with h(x, y) <= l <= 2(n) - l - h(y, z) and 2 vertical bar(l - h(x, y)), there exists a hamiltonian path R(x, y, z; l) from x to z such that d(R(x,y,z,l))(x, y) = l. Moreover, for any two distinct vertices x and y of Q,, and for any integer I with h(x, y) <= l <= 2(n-1) and 2 vertical bar(l - h(x, y)), there exists a hamiltonian cycle S(x, y; l) such that d(S(X,y;l))(x, y) = l. (C) 2008 Elsevier B.V. All rights reserved.
白色發光二極體用之新穎螢光組成物及其製造方法
(2008-08-16)
陳登銘
;
楊婉甄
本發明係提供一種白色發光二極體用之新穎螢光組成物,其係可轉換且發射波長由黃綠光調變至紅光,且同時具有金屬硫化物Ba2-xDxES3化學組成之螢光組成物,其中D為Ce^3^+、Eu^2^+或者該等二離子之組合;E為Mg、Zn或該等二元素之組合。並且其中x之數値範圍為0.0001≦x≦1。而且,本發明之螢光組成物於380-450nm波長光源的激發下,其色度座標値為0.25≦x≦0.70,0.20≦y≦0.50之範圍內。
影像式指向方向之偵測系統及方法
(2008-08-16)
傅智銘
;
黃仲陵
;
簡敬宇
本發明提供一種影像式指向方向之偵測系統及方法,其係以兩台或以上之影像擷取器擷取使用者之數張指向媒介物之影像,如徒手手臂或原子筆之長條狀物體,並以一處理器對擷取之數張指向媒介物影像進行影像處理,機率運算,以穩定的定位出空間中目標位置的三維座標。本發明不需使用任何定位手套或標記手套即可偵測出使用者指向空間中之任意目標點,並且可於工作空間中任意走動也可保持高辨析度及高穩定度,可應用於簡報系統中,作為取代雷射筆或滑鼠之人機介面,或使用於空間中家用電器之指向使用。
低功率動態序向控制多工器
(2008-08-16)
黃俊達
;
陳嘉怡
一種低功率動態序向控制多工器,係在原有之多工器旁邊再加一個序向電路。將原有2^N-1個多工器之N條控制線經過該序向電路分析考量各個控制訊號之前後關係,以動態產生M條控制線於實際控制N至2^N-1組之子多工器,且其關係係為N小於等於M,M小於等於2^N-1(N≦M≦2^N-1),以致能將各子多工器之控制訊號予以獨立,而減少不必要之變換活動,使整體多工器之變換動作降到最低,沒有必要轉換之子多工器則不需動作,進而降低整體之功率損耗。
壓縮／解壓縮裝置及其方法
(2008-08-16)
王志男
;
鍾崇斌
本發明係揭露一種壓縮/解壓縮裝置及其方法。壓縮裝置至少包含一儲存模組、一分群模組、一壓縮模組以及一處理模組。分群模組係分群此資料為複數個基本資料壓縮單元,壓縮模組係依據一壓縮演算法,以壓縮這些基本壓縮資料單元,而產生複數個已壓縮資料單元,處理模組係依據對應這些基本壓縮資料單元之一樹狀結構,及這些已壓縮資料單元之長度資訊,以產生一索引表。當使用者欲讀取某一位址之解壓縮資料時,解壓縮裝置係對此位址進行一邏輯運算,並依據邏輯運算所產生之一結果,自索引表中選出一長度資訊,再依據一解壓縮演算法,以解壓縮此長度資訊所對應之已壓縮資料單元,而產生此解壓縮資料。
增加虛擬天線於多輸入多輸出通道球體解碼器的方法
(2008-08-16)
桑梓賢
;
洪晉運
一種增加虛擬天線於多輸入多輸出通道球體解碼器的方法。利用一個簡單及有效的方法來搜尋與設定球體的初始半徑,因為初始半徑的範圍在球體解碼器的運算複雜性上扮演著一個重要的角色。此外,在多輸入多輸出通道的使用上,當傳送天線個數大於接收天線個數時,會造成多輸入多輸出通道的等效矩陣秩不足(rand-deficient),而使得球體解碼運算器無法使用。因此透過增加虛擬天線的方法使多輸入多輸出通道矩陣能維持滿秩(full rank),進而使球體解碼運算器仍可使用。該球體半徑設定法配合該增加虛擬天線法不但可以維持球體解碼運算器高效能的特點,同時也不影響原有的低運算量的特性。
精細頻寬調控的仲裁器及其仲裁方法
(2008-08-16)
黃俊達
;
林步青
;
李耿維
;
周景揚
一種精細頻寬調控的仲裁器及其仲裁方法,在複數個主控裝置提出滙流排使用要求時決定該滙流排的使用權,該些主控裝置具有即時及/或頻寬需求,且分別被預設一票數,該仲裁器包括一即時處理器、一頻寬調節器以及一加權隨機仲裁管理器。該即時處理器同意最緊急的滙流排使用要求,該頻寬調節器根據該些主控裝置的頻寬需求是否已滿足,並限制該些已滿足頻寬需求的主控裝置提出滙流排使用要求,該加權隨機仲裁管理器根據該些主控裝置的票數及該些主控裝置提出滙流排使用要求的情形,加權隨機地同意其中一滙流排使用要求。
POLY 368-Synthesis of photoisomerizable block copolymers by atom transfer radical polymerization
(2008-08-17)
Huang, Chih-Feng
;
Matyjaszewski, Krzysztof
;
Chang, Feng-Chih
;
Russell, Thomas P.
;
應用化學系
INOR 423-Fabrication of organic modified mesoporous TiO2 with high photocatalytic activity
(2008-08-17)
Chang, Sue-min
;
Shih, Chia-hsuan
;
環境工程研究所
;
Institute of Environmental Engineering
POLY 467-Synthesis and electroluminescent properties of polyacetylenes and poly(2,3-diphenyl-1,4-phenylene vinylene) derivatives
(2008-08-17)
Hsu, Chain-Shu
;
應用化學系
;
Department of Applied Chemistry
POLY 369-Controllably living polymerizations of poly(e-caprolactone)-block-poly(4-vinylpyridine) for two-phase extraction of metal ions
(2008-08-17)
Lu, Chu-Hua, Jr.
;
Huang, Chih-Feng
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry