首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  免费   1篇
电工技术   1篇
综合类   1篇
金属工艺   1篇
机械仪表   1篇
建筑科学   1篇
能源动力   1篇
轻工业   2篇
一般工业技术   3篇
自动化技术   2篇
  2019年   1篇
  2015年   1篇
  2013年   3篇
  2011年   1篇
  2007年   1篇
  1998年   1篇
  1997年   2篇
  1992年   2篇
  1991年   1篇
排序方式: 共有13条查询结果,搜索用时 942 毫秒
1.
There is an apparent anomaly in the notion that connectionism, which is fundamentally a new technology, has considerable philosophical significance. Nonetheless, connectionism has been widely viewed as having implications for symbol grounding, notions of structured representation and compositionality, as well as the issue of nativism. In this paper, we consider each of these issues in detail and find that the current state of connectionism does not warrant the magnitude of many of the philosophical conclusions drawn from it. We argue that connectionist models are no more 'grounded' than their classical counterparts. In addition, since connectionist representations typically are ascribed content through semantic interpretation based on correlation, connectionism is prone to a number of well known philosophical problems facing any kind of correlational semantics. However, we suggest that philosophy may be ill advised to ignore the development of connectionism, particularly if connectionist systems prove to be able to learn to handle structured representations.  相似文献   
2.
An agile manufacturing workcell design   总被引:1,自引:0,他引:1  
This paper introduces a design for agile manufacturing worked Is intended for light mechanical assembly of products made from similar components (i.e., parts families). We define agile manufacturing as the ability to accomplish rapid changeover from the assembly of one product to the assembly of a different product. Rapid hardware changeover is made possible through the use of robots, flexible part feeders, modular grippers, and modular assembly hardware. The division of assembly, feeding, and unloading tasks between multiple robots is examined with prioritization based upon assembly time. Rapid software changeover will be facilitated by the use of a real-time, object-oriented software environment utilizing graphical simulations for off-line software development. An innovative dual VMEbus controller architecture permits an open software environment while accommodating the closed nature of most commercial robot controllers. These agile features permit new products to be introduced with minimal downtime and system reconfiguration.  相似文献   
3.
While policy makers in different parts of the world are worried about the supposedly negative consequences of spatial concentrations of ethnic minorities and/or disadvantaged people, researchers continue the debate about the desirability and feasibility of social mix. In this article, we add to this literature by focusing on the often neglected, but crucial practices and discourses of the privileged in urban and suburban neighborhoods. Drawing on in‐depth interviews with 74 white, middle class residents of eight different neighborhoods of the Ghent urban region in Belgium, we demonstrate that few middle class whites actually want to live in a mixed neighborhood. We also make it clear that those living in diversity do not necessarily take up the roles they are expected to take up by the advocates of social mix policies. Drawing on these findings, we propose to broaden the research agenda of studies on segregation and social mix.  相似文献   
4.
LARSON  T. NICK  MARCH  HEATHER  KUSIAK  ANDREW 《IIE Transactions》1997,29(4):337-348
This paper presents a procedure for warehouse layout. It employs the principles of class-based storage to increase floor space utilization and decrease material handling. Three phases of the procedure are outlined: (1) determination of aisle layout and storage zone dimensions, (2) assignment of material to a storage medium, and (3) allocation of floor space. An industrial case study illustrates the procedure for a warehouse required to store 739 different products totaling more than 10000 pallets of material. An improved layout was developed and compared with the existing alternative. The proposed layout offered savings of more than 20 000 square feet of floor space and an approximately 45% reduction in material handling distance.  相似文献   
5.

ABSTRACT

A series of extracts from vinification by‐products, generated under specified, optimal conditions, were tested for their efficiency to inhibit lipid peroxidation in lecithin liposomes at various pH values. Lipid peroxidation was assessed by measuring the kinetics of CDV onset, which over a period of 6 days was found to obey zero‐order kinetics. As positive control samples the synthetic antioxidant, butylated hydroxytoluene and the natural quercetin were also considered. The results obtained showed that the most distinct inhibition as compared with control sample (no antioxidant added) was found upon addition of grape stem extract from the variety Vitis vinifera var. Moschofilero at pH 8, with the kinetics constant (k) being 6.6 × 10−2 CDV/d. By contrast, seed extract from the same variety at pH 2 was prominently prooxidant, with k = 50.7 × 10−2 CDV/d. Extracts from both stems and seeds exhibited large variations as a function of pH, with stem extracts being in general more efficient than seed extracts, but no consistent trend in response to pH was observed. This outcome clearly pointed to efficiency dependence upon both the composition of the extracts and pH.

PRACTICAL APPLICATIONS

Because the use of antioxidants in food industry is indispensable, the study of the efficiency of certain widely used plant extracts possessing antioxidant properties becomes imminent. This is because the deployment of natural antioxidants in food matrices has often been accompanied by major discrepancies concerning their efficiency to shield against rancidity. Thus, revealing details on the antioxidant behavior of natural extracts with regard to significant food characteristics, such as pH, is of undisputed importance in utilizing these extracts in a technologically rational way. The results from this study showed that extracts from vinification by‐products, and presumably other extracts from various plant sources, might have variable behavior with regard to inhibiting and/or promoting lipid peroxidation. As this might depend on the pH of the matrix used or other intrinsic factors, the antioxidant potency of a particular extract can be reliably assessed only by case experimentation.
  相似文献   
6.
胡敏素在水溶液中吸附镍   总被引:1,自引:0,他引:1  
通过液闪法分析得到胡敏素可富集镍,但是吸附受介质pH值、胡敏素用量和水相镍初始浓度等因素的影响。泥煤或胡敏素镍溶液紫外光谱的变化说明胡敏酸、富里酸和胡敏素3者之间或许存在可逆转化。胡敏素对镍的吸附反应可用Freundlich方程很好地进行描述,胡敏素吸附镍Freundlich吸附指数0.684 4推导出吸附反应以镍双配位形态为主。泥煤和胡敏素吸附镍Freundlich吸附指数(0.638 2,0.684 4)和吸附系数常用对数值(1.693 2,1.711 5)数值非常接近,表明胡敏素组分可能决定了泥煤的吸附能力,因此胡敏素将可作为有潜力的可渗透性屏障地质材料。  相似文献   
7.
8.
The development of efficient algorithms for learning from large relational databases is an important task in applicative machine learning. In this paper, we study knowledge discovery in relational databases and develop an attribute-oriented learning method which extracts generalization rules from relational databases. The method adopts the artificial intelligence “learning-from-examples” paradigm and applies in the learning process an attribute-oriented concept tree ascending technique which integrates database operations with the learning process and provides a simple and efficient way of learning from databases. The method learns both characteristic rules and classification rules of a learning concept, where a characteristic rule characterizes the properties shared by all the facts of the class being learned; while a classification rule characterizes the properties that distinguish the class being learned from other classes. The learning result could be a conjunctive rule or a rule with a small number of disjuncts. Moreover, learning can be performed with databases containing noisy data and exceptional cases using database statistics. Our analysis of the algorithms shows that attribute-oriented induction substantially reduces the computational complexity of the database learning process. Le développement d'algorithmes efficaces permettant l'apprentissage à partir de bases de donnees relationnelles est une fonction importante de l'apprentissage automatique applicatif. Dans cet article, les auteurs examinent la découverte des connaissances dans les bases de données relationnelles et élaborent une méthode d'apprentissage orientée sur l'attribut qui extrait des bases de données relationnelles les règies de généralisation. La méthode adopte le paradigme d'apprentissage à partir d'exemples et applique au processus d'apprentissage la technique de l'arbre des concepts orientés sur l'attribut qui incorpore les opérations de base de données au processus d'apprentissage, ce qui permet d'obtenir une méthode simple et efficace d'apprentissage à partir des bases de données. La méthode fait l'apprentissage des règies caractéristiques et des règies de classification d'un concept d'apprentissage; la règie caractéristique qualifie les pro-priétés communes à tous les faits d'une categorie faisant l'objet d'un apprentissage alors que la règie de classification caractérise les propriétés qui distinguent la catégorie faisant l'objet d'un apprentissage des autres catégories. Le résultat peut ětre une règie conjonctive ou une règie ayant un petit nombre de disjonctifs. Qui plus est, 1′apprentissage peut se faire avec des bases de données contenant des donnees bruitees et des cas exceptionnels utilisant des statistiques de bases de données. L'analyse des algorithmes démontre que l'induction orientée sur l'attribut réduit considérablement la complexité informàtique du processus d'apprentissage des bases de données.  相似文献   
9.
This paper describes an active phase shifter with a large amount of variable phase. We propose a design that has second-order all-pass network characteristics and that uses a tunable ferroelectric capacitor. The transmitted phase is changed by varying the capacitance of a ferroelectric capacitor. A computer simulation is presented that shows that the network, even with markedly non-ideal transistors, can provide a true all-pass response over the frequency band of interest (100 MHz–400 MHz). These simulated results demonstrate an analog tunability of about 200° with a gain variation of about 3 dB at 300 MHz—when using a Ba0.96Ca0.04Ti0.84Zr0.16O3 (BCTZ) capacitor with a tunability of 2:1. The simulation performed at 300 MHz because the physical layout of the real life circuit will be done mostly with the discrete components. As the self resonance frequency of most of the discrete components lies in the few hundreds of MHz range, our preferred frequency is a practical one to deal with. The simulation also predicts a flat band gain of approximately 10 dB with ± 2 dB of gain ripple.  相似文献   
10.
Risk communication theory is used to address consumer concerns about food safety and pesticide residues. Risk perception is a function of actual hazard and "outrage"factors. If concerns are acknowledged and information is provided on how risks are being addressed, the outrage component of perception is reduced. Two 2-min videos were prepared to present information on the environmentally responsive integrated pest management (IPM) approach to farming. The video was shown to a total of 197 consumers in controlled group settings. Although about 90% of participants expressed confidence in the safety of produce grown in California and the United States, 40% said they avoided some produce items due to safety concerns. Pre-and post-attitude assessments and group discussions documented a significant change in attitudes toward food safety, farming practices, and university efforts to help farmers. This project indicates that consumer concerns are significantly reduced when their knowledge of IPM practices is increased.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号