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排序方式: 共有122条查询结果,搜索用时 15 毫秒
1.
针对当前大型互联网站提升用户体验的需求,本研究创造性地提出基于本体的用户行为分析引擎的思想,它通过上下文感知技术,实时获取用户访问页面时的上下文信息(以下也称为动态行为),基于本体对用户行为建模,建立基于规则的上下文推理算法,对监测到的动态用户行为进行实时推理,及时反馈结果信息给用户。实验表明:本研究理论上独辟蹊径,设计实现上结合了云存储技术,能够一定程度改善用户体验效果。 相似文献
2.
Hydrogenation of p‐Nitrophenol to p‐Aminophenol as a Test Reaction for the Catalytic Activity of Supported Pt Catalysts 下载免费PDF全文
Michael Goepel Majd Al‐Naji Patrick With Gerald Wagner Oliver Oeckler Dirk Enke Roger Gläser 《化学工程与技术》2014,37(3):551-554
Hydrogenation of p‐nitrophenol (PNP) to p‐aminophenol (PAP) using NaBH4 as a reducing agent was studied as a test reaction for determining the catalytic activity of supported Pt catalysts. The initial reaction rate, which is accessible within less than 10 min via online UV‐vis spectroscopy at room temperature, ambient pressure, and in water as solvent, was applied as measure for catalytic activity. For three Pt catalysts supported on porous SiO2, porous glass, and Al2O3, respectively, significant differences in the catalytic activity by almost one order of magnitude were observed. However, especially in the case of very active catalysts, limitations of the reaction by internal or external mass transfer have to be considered. 相似文献
3.
In the present paper, we plan to introduce a new procedure for learner’s assessment in the learning environment in a way true to reality by using fuzzy logic. In this evaluation, learner’s responses are accompanied by a degree of certainty expressed by him. This method allows detection of problems encountered by the learner and also to fix the concepts mastered and those that are not. It is a diagnostic procedure that improves the process of content adaptation and self-adjustment on the one hand and makes the knowledge model clearly interpretable and more understandable to learner and tutor/teacher/head teacher on the other hand. 相似文献
4.
In this paper, the effect of horizontal bracing on enhancing the resistance of steel moment frames against progressive collapse is investigated. Previously designed 6 bay by 3 bay 18‐story steel frame prototype building with 6 m bay span (namely, unbraced frame), which was susceptible to progressive collapse, is retrofitted by four types of horizontal bracing systems on the perimeter of the topmost story and analyzed using 3D nonlinear dynamic method. Six different cross‐sections for each bracing system type are considered, and the capacity curves for each model are obtained. Three column removal circumstances, namely, Edge Short Column, First Edge Long Column, and Edge Long Column are considered in this paper. The results imply that horizontal bracing would increase the resistance of moment frames against progressive collapse. However, one of the bracing types in which axial compressive force is created in braces is not appropriate for retrofitting. 相似文献
5.
One of the main reasons behind the appearance of early distresses in Jordan roads and the low surface skid resistance is the use of marginal quality limestone aggregate. Large quantities of good quality basalt are available in the Northeastern parts of Jordan. In this research, the possibility of improving the properties of local asphalt concrete mixes by replacing different portions of the normally used limestone aggregate by basalt was investigated. The replacement included total replacement of the limestone by basalt, replacing the coarse aggregate, and replacing the fine aggregate. Results showed that the optimal mix was the mix that had basalt coarse aggregate and limestone fine aggregate. In order to overcome the stripping potential of the optimal mix, 20% of the filler portion of the aggregate, material smaller than 0.075 mm, was replaced by lime. The optimal mix showed superiority, over the tested mixes, in all the evaluated properties, which were Marshall Stability, indirect tensile strength, stripping resistance, resilient modulus, dynamic creep, fatigue, and rutting. 相似文献
6.
M. Hossein Taghavi Arshan Naji Leonid Belostotski James W. Haslett 《Analog Integrated Circuits and Signal Processing》2013,77(2):221-233
This paper discusses the use of mutli-path inductorless transimpedance amplifiers (TIAs), consisting of several different second-order shunt-feedback sub-TIAs (SF-sTIAs) driven by the photodiode, to break the single-stage technology-dependent transimpedance limit. The advantage of the MP-TIA that is explored in this work is in its third-order transfer function, which provides additional degrees of freedom in tailoring the performance. Pole and zero locations of the MP-TIA transfer function are examined and verified with behavioural simulations. The theoretical transimpedance limit for MP-TIAs based on two SF-sTIAs is derived. The possibility of further increasing the transimpedance limit vs bandwidth trade-off by combining three and four sub-TIAs is investigated with simulations. A transistor-level design example of an MP-TIA is presented. The 0.13-μm CMOS MP-TIA achieves the largest figure-of-merit among published TIAs. 相似文献
7.
DA Alexander AA Naji SB Pinion J Mollison HC Kitchener DE Parkin DR Abramovich IT Russell 《Canadian Metallurgical Quarterly》1996,312(7026):280-284
OBJECTIVE: To compare in psychiatric and psychosocial terms the outcome of hysterectomy and endometrial ablation for the treatment of dysfunctional uterine bleeding. DESIGN: Prospective randomised controlled trial. SETTING--Obstetrics and gynaecology department of a large teaching hospital. SUBJECTS: 204 women with dysfunctional bleeding for whom hysterectomy would have been the preferred treatment were recruited over 24 months and randomly allocated to hysterectomy (99 women) or to hysteroscopic surgery (transcervical resection (52 women) or laser ablation (53 women). MAIN OUTCOME MEASURES: Mental state, martial relationship, psychosocial and sexual adjustment in assessments conducted before the operation and one month, six months, and 12 months later. RESULTS: Both treatments significantly reduced the anxiety and depression present before the operation, and there were no differences in mental health between the groups at 12 months. Hysterectomy did not lead to postoperative psychiatric illness. Sexual interest after the operation did not vary with treatment. Overall, 46 out of 185 (25%) women reported a loss sexual interest and 50 out of 185 (27%) reported increased sexual interest. Marital relationships were unaffected by surgery. Personality and duration of dysfunctional uterine bleeding played no significant part in determining outcome. CONCLUSIONS: Hysteroscopic surgery and hysterectomy have a similar effect on psychiatric and psychosocial outcomes. There is no evidence that hysterectomy leads to postoperative psychiatric illness. 相似文献
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9.
Young (7 days old), middle-aged (30 days old), and old (50 days old) Drosophila melanogaster males were used in an inhibitory conditioning of the proboscis-extension response. Two reinforcement schedules were applied, constant vs. partial. Partial reinforcement increased the number of trials needed to reach the learning criterion to the same extent in all age groups. Young flies needed fewer trials to reach the criterion than both middle-aged and old flies, which did not differ from each other. Extinction was delayed in the partial reinforcement groups by the same amount in all age groups. The slowest rate of extinction was observed in the old group and the fastest for the middle-aged flies. The results are discussed in connection with hypotheses that consider extinction an index either of behavioral rigidity or of strength of the initial learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Comments on the article by L. L. Carstensen et al (see records 1999-10334-001) which argues that time perception is integral to human motivation. The present author argues that the question of time and how people view it is not merely about cognitive or emotional behavior; rather, it is more existential, spiritual, and philosophical in nature. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献