• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1667680
  • 313057
  • 10220
  • 6567
  • 1227
  • 874
  • 182
  • 181
  • 180
  • 176
  • 167
  • 162
  • 139
  • 129
  • 59
  • Tagged with
  • 132590
  • 77323
  • 72887
  • 66614
  • 63660
  • 55173
  • 49126
  • 47602
  • 45573
  • 41193
  • 36013
  • 34476
  • 33801
  • 32112
  • 31294
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
590381

A Study of Hierarchical Key Management Schemes Based on Elliptic Curves / 植基於橢圓曲線的階層式金鑰管理之研究

Jia-Hao Lee, 李家豪 January 2003 (has links)
碩士 / 東海大學 / 資訊工程與科學系 / 91 / In a user hierarchy that users are authorized and classified into different privilege classes, a user belonging to higher-privileged class will have access right to messages created or owned by users in a lower-privileged class; while the opposite is not allowed. To meet the access control requirement in a user hierarchy, Lin proposed a dynamic key management scheme suitable for hierarchical control systems and that appeared in Computer Communications. It is useful in solving the key management problem for a privileged hierarchy using related parameters. However, the related parameters are generated by modulo exponential computation. This seems not efficient enough for a system with frequently changing requirements. Besides, Lee and Hwang proposed two comments to this scheme. To eliminate the possible drawbacks as discussed in their comments, Cho proposed modifying the scheme by adding a parameter. Although Cho’s scheme is an improvement in security, it is not as efficient as Lin’s scheme. In this thesis, we propose a novel scheme, based on the elliptic curves that eliminates the drawbacks and has better performance. Furthermore, we also use the advantages of smart card to enhance our proposed scheme.
590382

A Study of Authenticated Key Agreement Schemes Based on Elliptic Curve / 植基於橢圓曲線密碼學之具有身分驗證金鑰交換協定研究

Kuo-Jung Huang, 黃國榮 January 2003 (has links)
碩士 / 東海大學 / 資訊工程與科學系 / 91 / In this thesis, we proposed two authenticated key agreement protocols on Elliptic Curve Cryptography. The basic Diffie-Hellman protocol doesn’t authenticate the communicating entities and is vulnerable to the man-in-the-middle attack. To provide authenticity to key agreement protocols, we respectively use shared-password in our first protocol and certificates to our second protocol. Besides, we applied the elliptic curve cryptography for the generation of keys to improve the efficiency. In the first protocol, the authenticated message is generated with the shared-password and the receiver can verify it with his shared-password to ascertain the sender’s identify. The second protocol is one round tripartite authenticated key agreement protocol on the public key infrastructure. Each entity in the second protocol must send a message including his own signature to demonstrate that he is the owner of the certificate. To avoid an adversary intercepting the signature and resending it to others, signature of the sender includes his ephemeral public key and a short-lived timestamp. Besides, we provide the security analysis about our protocols.
590383

The Geodetic Spectra and the Strong Geodetic spectra of Graphs / 圖的最短路徑譜及強最短路徑譜

Hong-Tsu Wang, 王鴻志 January 2002 (has links)
碩士 / 東海大學 / 數學系 / 91 / For two vertices u and v in an oriented graph D, a u-v geodesic is a directed path of minimum length from u to v. Let I(u,v) denote the set of all vertices lying on a u-v geodesic or a v-u geodesic. If A is a subset of V(D), then I(A) is the union of all I(u,v) for u,v \in A. The geodetic number g(D) is the minimum cardinality of the subset A of V(D) with I(A)=V(D). For a nontrivial connected graph G, the geodetic spectrum of G is the set of geodetic numbers among the all orientations of G and the strong geodetic spectrum of G is the set of geodetic numbers among the all strongly connected orientations of G. In this paper, we investigate geodetic spectra and strong geodetic spectra of graphs. For the geodetic spectra of graphs, we demonstrate that for every two integers n and m with $1\leq n-1\leq m\leq (_2^n)$, there exists a connected graph G of order n and size m such that $S(G)=\{2,3,\ldots,n\}$. We also determine the geodetic spectra of complete r-partite graphs, cycles and trees. These results provide answers to a conjecture and two problems given by Chartrand and Zhang [9]. For the strong geodetic spectra of graphs, we show that the strong geodetic spectrum of each graph is the subset of $\{2, 3, \cdots , n-2\}$ and for every positive integers n, m, k with $2 \le k \le n-3$ and $n+k \le m\le {n \choose 2}-k$, we can construct a strongly connected oriented graph $D$ of order n and size m such that g(D)=k.
590384

Feedback Control of Stochastic H∞ with Bounded Real Lemma / 隨機H∞之迴授控制與界實引理

Yu-Ling Wei, 魏郁岭 January 2003 (has links)
碩士 / 東海大學 / 數學系 / 91 / Abstract In this paper we investigate the linear stochastic system and utilize the H∞-type controller for the stochastic plant. Bounded real lemma in linear stochastic system is adopted and proved, it is the main tool of this paper. We find the state feedback controller and the conditions of the output feedback controller by this lemma. A form of the feedback controller is solved with some specified constraints.
590385

Global Stability for the Lotka-Volterra Mutualistic System with Time-Delay / 具時滯參數之Lotka-Volterra互利共生系統之整體穩定性

Feng-Chun Hsu, 徐楓淳 January 2003 (has links)
碩士 / 東海大學 / 數學系 / 91 / In this thesis, we are concerned with the dynamical behavior of a two-species Lotka- Volterra mutualistic system with time delay. First of all, we use three different methods to discuss the global stability of the unique positive equilibrium point of a two-species Lotka-Volterra mutualistic system without time delay. Secondly, we study the change of the global stability for a two-species Lotka-Volterra mutualistic system with time delay. Finally, we illustrative our results by some examples.
590386

Isolation and identification of thermophilic aerobic xylan-degrading bacteria from Lushan hot spring,Central Taiwan / 中台灣廬山溫泉中嗜熱好氧木聚醣降解菌株之分離與鑑定

Hung-wei,Huang, 黃弘緯 January 2003 (has links)
碩士 / 東海大學 / 環境科學系 / 91 /
590387

The characters and sources identification of atmospheric polycyclic aromatic hydrocarbons at suburban and industrial areas in Taichung, Taiwan / 台灣台中地區市郊及工業區大氣中多環芳香族碳氫化合物之特性及來源鑑定

I-Lin Yang, 楊易霖 January 2003 (has links)
碩士 / 東海大學 / 環境科學系 / 91 / The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere were measured simultaneously at industrial area (Taichung Industrial Park, TIP) and suburban area (Tunghai University Campus, THUC) in central Taiwan, Taichung. At both sites, 24 h samplings for two consecutive days were performed between August 2002 and January 2003. Particle-bound PAHs (p-PAHs) were collected on quartz filters and gas-phase PAHs (g-PAHs) were measured on glass cartridges using PUF Sampler, respectively. The average g-PAHs (N = 19) concentrations at TIP and THUC sampling sites were found to be 1305.4 ng m-3 and 646.2 ng m-3; average p-PAHs (N = 19) concentrations at both sampling sites were recorded as 129.1 ng m-3 and 85.9 ng m-3, respectively. Correlation studies between PAHs concentrations and meteorological parameters revealed that temperature had greater effects on g-PAHs and p-PAHs, moreover, PAHs sources were resolved by using principal component analysis (PCA) and hierarchical cluster analysis (HCA). The major sources of PAHs were diesel vehicles and industrial source at TIP site. Moreover, incineration, gasoline vehicle and stationary emission sources such as power plant, industrial source and so on are the major contribution sources for PAHs at THUC sampling site.
590388

The applications of molecular dynamics simulations on proteins / 分子動態模擬於蛋白質上之應用

Chia-Ming Hsu, 許家銘 January 2003 (has links)
碩士 / 國立臺北科技大學 / 化學工程系碩士班 / 91 / In this study, molecular dynamics simulations were performed to investigate 1) the effects of various metal ions on the binding of substrate to human alcohol dehydrogenase β2β2; 2) the effects of solvent and temperature on the structural integrity of monomeric melittin; and 3) the chelating mechanisms of various metal ions to the His-tag motifs. For alcohol dehydrogenase, both structural and catalytic zinc ions, Zns and Zna, respectively, were shown to influence the structural integrity of the substrate binding pocket of the human alcohol dehydrogenase 22. By manual docking, the results indicated that the replacement of catalytic zinc ion or both catalytic and structural zinc ions with Cu2+ results in better substrate binding affinity (ethanol) than the wild type enzyme. Furthermore, the width of the bottleneck formed by L116 and V294 in the substrate binding pocket plays an important role for substrate entrance. For melittin, 200 ps molecular dynamics simulations were performed with temperature jump technique. The results demonstrated that the -helix content and melting temperature of melittin increased with increasing the aliphatic chain length of the alcohol and decreased with increasing simulation temperature. The weaker dielectric constant of longer aliphatic chain length of alcohol possibly reduces the hydrogen bonding between amide protons and surrounding solvent molecules, therefore stabilizes the secondary structure of melittin. For the chelating mechanisms of His-tag motifs, our simulations demonstrated that the chelation mostly involved the i and i+2 His residues for Ni2+, Zn2+, Cu2+, and Co2+, while the cooperation of 3 His residues was necessary when Fe3+ was involved in chelation with His-tags having more than 4 His residues. In addition, His-tag6 was found to have little effect on the structural integrity while the target protein contains more than 68 amino acid residues. We also detected that Ni2+ interacted with the imidazole nitrogen of His3 in the beginning of chelation and then entered into the pocket formed by His3 and His5 at 4 ns during the 10 ns molecular dynamics simulations.
590389

Application of Ant System on Clustering Analysis in Data Mining / 應用螞蟻系統於資料挖礦之集群分析

Shih-Hsiung Chou, 周仕雄 January 2003 (has links)
碩士 / 國立臺北科技大學 / 生產系統工程與管理研究所 / 91 / This study proposes two novel clustering analysis techniques, Ant System-based clustering algorithm (called ASCA in this study), which is the auto-clustering method, and Ant K-means algorithm (AK), which needs the number of clusters and its centroids as input. Both ASCA and AK are applying the concept of pheromone, i.e., the closer of two objects, the higher consistency of pheromones. This study compares computational performance for clustering problems of the other two methods including Self-Organizing Feature Map (SOM) and SOM+GA-based cluster method (S+G) via the 243 data set generated by Monte Carlo simulation. As this research, ASCA gets better computational performance than SOM which is auto-clustering algorithm, and ASCA+AK gets better computational performance than S+G which is a two-stage method to find the final solution. To further testify this novel proposed method, a useful comparison of four methods is employing the real case data. Recently, the price of plasma TV is gradually decreasing. It is necessary to rethink the strategy of the price of plasma TV in such a low-price strain. Therefore, this study intends to apply the proposed method to address the suggestions of the sale promotion to be aimed at the different clusters via the questionnaires. The result of clustering analysis from real case also shows that the performance of ASCA is better than SOM and ASCA+AK is also better than that of S+G according to total within cluster variance (TWCV).
590390

Effects of Manufacturer’s Perceptions of Upstream Market Orientation on Channel Relationships with Supplier / 製造商上游市場導向與供應商通路關係影響之研究

Wang, Chen Ching, 王振慶 January 2003 (has links)
碩士 / 國立臺北科技大學 / 生產系統工程與管理研究所 / 91 / This study examine to the influence manufacturer’s upstream market orientation the on channel relationships; such as, trust, cooperative norms, commitment ,and satisfaction. In addition, we use a channel conceptualization of market orientation but we only focus manufacturer’s perceptions of upstream market orientation in the conceptual framework. We sent a total of 400 questionnaires; as well as, the mailings had resulted in response from 76 manufacturers. By LISREL program, we are understand the effects of manufacturer’s perceived of UMO on trust, cooperative norms and commitment with supplier in industrial channel have positively signify. Moreover, the findings that manufacturer’s perception of trust has a direct affect on its perception of cooperative norms. However, the market-oriented behavior of findings that manufacturer-perceived of UMO was the lack of direct affects on the its perception of satisfaction with supplier in industrial relationship. We completely think the occidental measure scales of market orientation may be not to adjust measuring of oriental companies. Similarly, measuring channel relationships we think the measure scales may be different identify in occidental companies with oriental companies. We suggest that future research can discusses it.

Page generated in 0.9628 seconds