排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Zhe Liang Wanpracha Art Chaovalitwongse Meeyoung Cha Sue B. Moon 《Computers & Operations Research》2010,37(10):1731-1739
This paper presents a redundant multicast routing problem in multilayer networks that arises from large-scale distribution of realtime multicast data (e.g., Internet TV, videocasting, online games, stock quotes). Since these multicast services commonly operate in multilayer networks, the communications paths need to be robust against a single router or link failure as well as multiple such failures due to shared risk link groups (SRLGs). The main challenge of this multicast is to ensure the service availability and reliability using a path protection scheme, which is to find a redundant path that is SRLG-disjoint (diverse) from each working path. The objective of this problem is, therefore, to find two redundant multicast trees, each from one of the two redundant sources to every destination, at a minimum total communication cost whereas two paths from the two sources to every destination are guaranteed to be SRLG-diverse (i.e., links in the same risk group are disjoint). In this paper, we present two new mathematical programming models, edge-based and path-based, for the redundant multicast routing problem with SRLG-diverse constraints. Because the number of paths in path-based model grows exponentially with the network size, it is impossible to enumerate all possible paths in real life networks. We develop three approaches (probabilistic, non-dominated and nearly non-dominated) to generate potentially good paths that may be included in the path-based model. This study is motivated by emerging applications of internet-protocol TV service, and we evaluate the proposed approaches using real life network topologies. Our empirical results suggest that both models perform very well, and the nearly non-dominated path approach outperforms all other path generation approaches. 相似文献
2.
Iasemidis LD Shiau DS Chaovalitwongse W Sackellares JC Pardalos PM Principe JC Carney PR Prasad A Veeramani B Tsakalis K 《IEEE transactions on bio-medical engineering》2003,50(5):616-627
Current epileptic seizure "prediction" algorithms are generally based on the knowledge of seizure occurring time and analyze the electroencephalogram (EEG) recordings retrospectively. It is then obvious that, although these analyses provide evidence of brain activity changes prior to epileptic seizures, they cannot be applied to develop implantable devices for diagnostic and therapeutic purposes. In this paper, we describe an adaptive procedure to prospectively analyze continuous, long-term EEG recordings when only the occurring time of the first seizure is known. The algorithm is based on the convergence and divergence of short-term maximum Lyapunov exponents (STLmax) among critical electrode sites selected adaptively. A warning of an impending seizure is then issued. Global optimization techniques are applied for selecting the critical groups of electrode sites. The adaptive seizure prediction algorithm (ASPA) was tested in continuous 0.76 to 5.84 days intracranial EEG recordings from a group of five patients with refractory temporal lobe epilepsy. A fixed parameter setting applied to all cases predicted 82% of seizures with a false prediction rate of 0.16/h. Seizure warnings occurred an average of 71.7 min before ictal onset. Similar results were produced by dividing the available EEG recordings into half training and testing portions. Optimizing the parameters for individual patients improved sensitivity (84% overall) and reduced false prediction rate (0.12/h overall). These results indicate that ASPA can be applied to implantable devices for diagnostic and therapeutic purposes. 相似文献
3.
The present work investigated drying characteristics and inactivation of urease in soybean dried by superheated-steam and hot-air fluidized beds. The value of effective diffusion coefficient, which was determined by a method of slopes, was increased with increased drying temperature and increased moisture content. Furthermore, it depended on the type of heating medium, with higher moisture diffusion for soybean dried by hot air. Inactivation of the urease enzyme in both media showed difference in rate, in which the enzymatic inactivation was faster for soybean dried in superheated steam than in hot air. For the individual heating medium, the modified first-order reaction was adequately fitted to experimental data. The rate of inactivation was found to increase as the temperature and moisture content were increased. The urease enzyme was inactivated, along with maintaining protein solubility and lysine content being in standard range, as soybean was treated at a temperature between 135 and 150 °C for the hot air and the treatment temperature could be reduced to be lower than 135 °C by using superheated steam. 相似文献
4.
Paveena Srirangsan Kiyoshi Kawai Naoko Hamada-Sato Manabu Watanabe Toru Suzuki 《Food chemistry》2010,119(1):209-213
In order to improve the remaining activity of a practically important freeze-dried enzyme, xanthine oxidase (XOD), the effects of disaccharide (sucrose and trehalose), polymer (bovine serum albumin: BSA and dextran) and a mixture of them on the loss of XOD activity during freeze-drying and subsequent storage were investigated. All samples were amorphous solids and their glass transition temperatures (Tg) were evaluated by using differential scanning calorimetry. Although dextran showed no stabilizing effect on the freeze-dried XOD, the others protected XOD from the activity loss during freeze-drying to a certain extent. It was found that the mixture of disaccharide (sucrose or trehalose) and BSA improved the XOD activity synergistically. The XOD activity of the samples decreased gradually during storage at a temperature range of between 25 and 60 °C. Samples stored at temperatures below the Tg showed a lower loss of XOD activity than those stored at just the Tg. 相似文献
5.
Paveena Tangudom Ekachai Wimolmala Benjaphorn Prapagdee 《Polymer-Plastics Technology and Engineering》2018,57(18):1963-1976
Polymer blends of poly(methyl methacrylate)(PMMA) and acrylic rubber(AR) were manufactured with the addition of titanium dioxide (TiO2). TiO2 was initially added to the AR phase in AR/PMMA blends. The impact strength of PMMA improved with AR loading. The addition of TiO2 appeared to decrease the tensile properties of the blends with AR of 10-30?wt% of AR, but increased with AR of 40-50?wt%, this being related to distribution level of TiO2. UV radiation deteriorated the overall mechanical properties, where TiO2 could retain the properties. To achieve acceptable antibacterial performance, AR loadings of 40 and 50?wt% in AR-TiO2/PMMA blends are recommended, together with TiO2 loadings of 1.5?pph and 0.5?pph, respectively. 相似文献
6.
Minghai Yuan Kun Deng W.A. Chaovalitwongse Hongyan Yu 《The International Journal of Advanced Manufacturing Technology》2018,99(5-8):1061-1075
Nowadays, cloud manufacturing (CMfg) as a new service-oriented manufacturing mode has been paid wide attention around the world. However, one of the key technologies for better implementing CMfg services is how to address the problems faced by distributed massive and polymorphic data analysis and processing of manufacturing resource services in CMfg environment. In order to handle the problems, and promote development integration and business application of data mining, the research on technologies and application of data mining for cloud manufacturing resource (CMR) services has been carried out in this paper. The data mining application model and multi hierarchy architecture of CMR services are designed, and the topology of resource service data integrating process based on multi-Agent is presented. Besides, the preprocessing method of manufacturing resource data is proposed, and a CMR virtual data warehouse is established as well. In addition, an improved genetic algorithm oriented to manufacturing resource services is put forward, so as to achieve efficient searching and mining of massive polymorphic data. Finally, a case study is employed to illustrate the effectiveness and applicability of the proposed method in CMR service platform. 相似文献
7.
Paveena Laokul Prasit Thongbai Teerapon Yamwong Santi Maensiri 《Journal of Superconductivity and Novel Magnetism》2012,25(4):1195-1201
Nanocrystalline Ni0.5Cu0.3Zn0.2Fe2O4 (NCZFO) powder was fabricated by a modified sol?Cgel method and then the compacted powder of NCZFO was sintered at 950, 1000, and 1100?°C for 6 h. The dielectric and electrical properties of sintered samples were investigated as functions of frequency and temperature. All of the NCZFO samples exhibit the high dielectric response behavior and show the Debye-like relaxation, which is attributed to the Maxwell?CWagner polarization and thermally activated mechanisms. The impedance spectroscopy analysis reveals that the NCZFO ceramics are electrically heterogeneous. The sintering temperature has significant influence on the dielectric dispersion behavior of the NCZFO samples, which should be mainly attributed to the large variation of the grain conduction activation energies. 相似文献
8.
Jitti Jungwattanakit Manop Reodecha Paveena Chaovalitwongse Frank Werner 《Computers & Operations Research》2009
This paper considers a flexible flow shop scheduling problem, where at least one production stage is made up of unrelated parallel machines. Moreover, sequence- and machine-dependent setup times are given. The objective is to find a schedule that minimizes a convex sum of makespan and the number of tardy jobs in a static flexible flow shop environment. For this problem, a 0–1 mixed integer program is formulated. The problem is, however, a combinatorial optimization problem which is too difficult to be solved optimally for large problem sizes, and hence heuristics are used to obtain good solutions in a reasonable time. The proposed constructive heuristics for sequencing the jobs start with the generation of the representatives of the operating time for each operation. Then some dispatching rules and flow shop makespan heuristics are developed. To improve the solutions obtained by the constructive algorithms, fast polynomial heuristic improvement algorithms based on shift moves and pairwise interchanges of jobs are applied. In addition, metaheuristics are suggested, namely simulated annealing (SA), tabu search (TS) and genetic algorithms. The basic parameters of each metaheuristic are briefly discussed in this paper. The performance of the heuristics is compared relative to each other on a set of test problems with up to 50 jobs and 20 stages and with an optimal solution for small-size problems. We have found that among the constructive algorithms the insertion-based approach is superior to the others, whereas the proposed SA algorithms are better than TS and genetic algorithms among the iterative metaheuristic algorithms. 相似文献
9.
World Wide Web - With growing concern of data privacy violations, privacy preservation processes become more intense. The k-anonymity method, a widely applied technique, transforms the data such... 相似文献
10.
To stabilize two freeze-dried enzyme mixtures, consisting of alkaline phosphatase, nucleoside phosphorylase and xanthine oxidase, the effects of sucrose–polymer (bovine serum albumin, gelatin, dextran, polyethylene glycol and polyvinylpyrrolidone) formulations on the remaining activity of the enzyme mixtures were investigated. The enzyme mixtures were freeze-dried with the additives, and then stored at 25, 40 and 55 °C. The glass transition temperatures (Tg) of the freeze-dried samples were assessed in order to determine their physical stability. The Tg values of sucrose–polymer formulations, with the exception of sucrose–polyethylene glycol, were higher than that of sucrose alone. Comparison of the remaining activities of freeze-dried samples showed that sucrose–bovine serum albumin and/or –gelatin prevented activity loss more effectively than did sucrose. Sucrose–polyethylene glycol showed protective ability equivalent to that of sucrose. On the other hand, sucrose–dextran and/or –polyvinylpyrrolidone diminished the stabilizing effect of sucrose. During storage, sucrose–gelatin prevented gradual activity loss to a much greater degree than did sucrose alone. 相似文献