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21.
We consider the problem of placing copies of objects in a distributed web server system to minimize the cost of serving read and write requests when the web servers have limited storage capacities. We formulate the problem as a 0–1 optimization problem and present a hybrid particle swarm optimization algorithm to solve it. The proposed hybrid algorithm makes use of the strong global search ability of particle swarm optimization (PSO) and the strong local search ability of tabu search to obtain high quality solutions. The effectiveness of the proposed algorithm is demonstrated by comparing it with the genetic algorithm (GA), simple PSO, tabu search, and random placement algorithm on a variety of test cases. The simulation results indicate that the proposed hybrid approach outperforms the GA, simple PSO, and tabu search. 相似文献
22.
Mahmood Mamdani 《Inter-Asia Cultural Studies》2016,17(1):68-83
This article focuses on epistemological decolonization, including knowledge production and its institutional locus – the university – in the post-independence African context. The article begins by problematizing both the concept and the institutional history of the university, in its European and African contexts, to underline the specifically modern character of the university as we know it and its genesis in post-Renaissance Europe. Against this background, the article traces post-independence reform of universities in Africa, which is unfolding in two waves: the first on access, Africanization, generating a debate between rights and justice; and the second on institutional reform, epitomized by the debate around disciplinarity. At the same time, the notions of excellence and relevance have functioned as code words, each signaling a different trajectory in the historical development of the university. Lastly, the article explores the role and tension between the public intellectual and the scholar from the perspective of decolonization. 相似文献
23.
CAI Jing ZHENG Ping MAHMOOD Qaisar ISLAM Ejazul HU Bao-lan WU Dong-lei 《浙江大学学报(A卷英文版)》2007,8(7):1149-1156
The optimal operation conditions in an anoxic sulfide oxidizing (ASO) bioreactor were investigated. The maximal removal rates for sulfide and nitrate were found to be 4.18 kg/(m3·d) and 1.73 kg/(m3·d), respectively. The volumetrical volumetric loading rates (LRs) observed through decreasing hydraulic retention time (HRT) at fixed substrate concentration are higher than those by increasing substrate concentration at fixed HRT. The sulfide oxidation in ASO reactor was partially producing both sulfate and sulfur; but the amount of sulfate produced was approximately one third that of sulfur. The process was able to tolerate high sulfide concentration, as the sulfide removal percentage always remained near 99% when influent concentration was up to 580 mg/L. It tolerated relatively lower nitrate concentration because the removal percentage dropped to 85% when influent con- centration was increased above 110 mg/L. The process can tolerate shorter HRT but careful operation is needed. Nitrate conversion was more sensitive to HRT than sulfide conversion since the process performance deteriorated abruptly when HRT was decreased from 3.12 h to 2.88 h. In order to avoid nitrite accumulation in the reactor, the influent sulfide and nitrate concentrations should be kept at 280 mg/L and 67.5 mg/L respectively. Present biotechnology is useful for removing sulfides from sewers and crude oil. 相似文献
24.
Kaya M Kaya G Kaya MD Atak M Saglam S Khawar KM Ciftci CY 《Journal of Zhejiang University. Science. B》2008,9(5):371-377
Chickpea is an important food legume crop of Turkey and is largely grown for human consumption on low moisture or salt-affected soils.The objective of the study was to find the effects of NaCl stress at electrical conductivities of 4.5,8.6,12.7 and 16.3 dS/m and seed sizes (7,8 and 9 mm) on germination and early seedling growth of three popular chickpea cultivars (AKN-97,Gokce and Uzunlu-99).Mean frequency of germination,germination time,germination index,root length,shoot length and seedling fresh weight showed seed size-dependent responses of cultivars to salt stress.In general,small seeds germinated and grew more rapidly compared to medium and large seeds of the same cultivars against all levels of salt stress,with the best results in cultivar Uzunlu-99.No effect of NaCl treatments was observed on frequency of germination; however,a drastic decrease in early seedling growth was recorded at increased NaCl concentrations.Regression analysis results showed a significantly positive rela-tionship (P<0.01) between seed size and mean germination time,whereas a significantly negative relationship was recorded between seed size and germination index,root length,shoot length.Moreover,linear regression values apparently confirmed that increased seed size in each cultivar affected decreased germination index,root and shoot lengths with enhanced mean germination time.Thus,it was concluded that the use of small seeds could considerably reduce the production costs of chickpea in salt-affected soils. 相似文献
25.
Mohammad Mohsen Shahmardan Mahmood Norouzi Mohammad Hassan Kayhani Amin Amiri Delouei 《浙江大学学报(A卷英文版)》2012,13(10):768-781
An exact analytical solution is obtained for convective heat transfer in straight ducts with rectangular cross-sections for the first time. This solution is valid for both H1 and H2 boundary conditions, which are related to fully developed convective heat transfer under constant heat flux at the duct walls. The separation of variables method and various other mathematical techniques are used to find the closed form of the temperature distribution. The local and mean Nusselt numbers are also obtained as functions of the aspect ratio. A new physical constraint is presented to solve the Neumann problem in non-dimensional analysis for the H2 boundary conditions. This is one of the major innovations of the current study. The analytical results indicate a singularity occurs at a critical aspect ratio of 2.4912 when calculating the local and mean Nusselt numbers. 相似文献
26.
Electronic resources and services in Pakistani university libraries: A survey of users' satisfaction
Muhammad Sajid Mirza Khalid Mahmood 《International Information and Library Review》2012,44(3):123-131
This study is an attempt to evaluate the effectiveness of electronic resources and services in Pakistani university libraries on the basis of users' satisfaction. A survey method was employed to conduct the research. Using convenience sampling, eight university libraries; four each from Islamabad and Lahore including two from the public sector and two from the private sector having IT applications, were included in the users survey. The total population (i.e., 40,236) of library users was very large; therefore, a reasonable, manageable and convenient sample of 800 library users, including 100 users each from the eight libraries was selected. A semi structured questionnaire was designed to collect data, while a five-point Likert Scale from 1 (Dissatisfied) to 5 (Extremely satisfied) was used to measure the satisfaction level of the respondent. The study concluded that Pakistani university libraries are offering effective electronic resources and services to their users. 相似文献
27.
ABSTRACT The present study was conducted to assess distance learning students’ perceptions about location and physical set up of libraries, collections, resources, and services rendered at thirty-four regional campuses as well as main campus libraries network of Allama Iqbal Open University (AIOU) all over Pakistan. During the spring semester of 2007, a questionnaire was mailed to 250 randomly selected students enrolled in eleven postgraduate programs throughout the country. The response rate was 61.2%, which was made up of 43.1% females and 56.9% males. A majority of the respondents were dissatisfied with the virtual reference services, online database facilities, interlibrary loan, library membership, and borrowing of library material from the AIOU libraries. They were satisfied with the location and physical setup of the libraries, the collections, and the resources of the libraries. The study revealed that most of the respondents used the libraries during workshops as well as for research purposes. The statistical analysis (t = 0.550, Sig. = 0.970) showed that there was no significant difference between the opinion of females and males. The data were analyzed using Statistical Package for Social Sciences (SPSS) for Windows version 10.0. 相似文献
28.
Farnaz Farnam Minoo Pakgohar Mandana Mirmohamadali Mahmood Mahmoodi 《Sex education》2013,13(2):159-168
The purpose of this study was to evaluate the effect of a special sex education program in sexual health on Iranian newly‐wed couples. A sample of 64 couples referred to three health centers of Tehran Medicine University, a few months prior to their marriage, were divided into case and control groups. The case group received three lecture sessions given by the researcher. These lectures consisted of different aspects of sexuality such as reproductive and sexual health, the sexuality response cycle and sexual communication. The control group received only the lectures that are presented normally in the marriage preparation program, based on family planning and personal health. Six months after the program, we assessed the sexual satisfaction, healthy behaviors and sexual health of the two groups. The results indicate that the sexual health in the case group is significantly improved compared with the control group. 相似文献
29.
Narges Adibsereshki Masoome Pourmohamadreza Tajrishi Mahmood Mirzamani 《Educational studies》2010,36(4):447-459
This study investigates the effectiveness of a preparatory programme on the acceptance of students with physical disabilities by their peers in inclusive schools in Tehran. The classrooms which had students with physical disabilities were included in this study. Two hundred and twenty‐one third‐ to fifth‐grade students (116 girls and 105 boys) were selected randomly and were placed in experimental and control groups. The Acceptance Scale (Form B) established by Voeltz was used to measure peer acceptance. Data were collected from two groups before and after applying the preparatory programme. The data were analysed by t‐test for independent groups and two‐way ANOVA. The results showed increase of acceptance in experimental group. Also in comparing the level of acceptance in girls and boys, the results indicated that the acceptance in girls were more than boys. 相似文献
30.
Mahmood QAISAR 《Journal of Zhejiang University. Science. B》2010,11(2):79-86
Bed expansion behavior and sensitivity analysis for super-high-rate anaerobic bioreactor (SAB) were performed based on bed expansion ratio (E), maximum bed sludge content (Vpmax), and maximum bed contact time between sludge and liquid (τmax). Bed expansion behavior models were established under bed unfluidization, fluidization, and transportation states. Under unfluidization state, E was 0, Vpmax was 4 867 ml, and τmax was 844–3 800 s. Under fluidization state, E, Vpmax, and τmax were 5.28%–255.69%, 1 368–4 559 ml, and 104–732 s, respectively. Under transportation state, washout of granular sludge occurred and destabilized the SAB. During stable running of SAB under fluidization state, E correlated positively with superficial gas and liquid velocities (ug and ul), while Vpmax and τmax correlated negatively. For E and Vpmax, the sensitivities of ug and ul were close to each other, while for τmax, the sensitivity of ul was greater than that of ug. The prediction from these models was a close match to the experimental data. 相似文献