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  • 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.
11

RFID Tag Design and Range Improvement

Chirammal Ramakrishnan, Rijwal 27 June 2012 (has links)
Radio Frequency Identification (RFID) is a short range radio technology for communication between two objects namely, a reader and a tag. Design of an RFID tag with the best range is always the motive of an RFID designer. In this thesis two RFID tags were simulated, designed and manufactured. The first one is a semi-passive RFID tag, which also serves as a discrete prototype tag for the research group to master RFID tag designs. The user can program and further extend the use of this tag according to the requirements. This RFID tag is provided with JTAG interface to program and debug. The read range of this prototype tag is found to be 1m with reader EIRP of 30dBm. The second design is a passive tag which can be commercialized. It achieves a competitive read range of 2.9m for reader EIRP of 21dBm. The read range when measured in a practical implementation inside a building corridor was 15m.
12

Utilizing Social Bookmarking Tag Space for Web Content Discovery: A Social Network Analysis Approach

Wei, Wei January 2010 (has links)
Social bookmarking has gained popularity since the advent of Web 2.0. Keywords known as tags are created to annotate web content, and the resulting tag space composed of the tags, the resources, and the users arises as a new platform for web content discovery. Useful and interesting web resources can be located through searching and browsing based on tags, as well as following the user-user connections formed in the social bookmarking community. However, the effectiveness of tag-based search is limited due to the lack of explicitly represented semantics in the tag space. In addition, social connections between users are underused for web content discovery because of the inadequate social functions. In this research, we propose a comprehensive framework to reorganize the flat tag space into a hierarchical faceted model. We also studied the structure and properties of various networks emerging from the tag space for the purpose of more efficient web content discovery.The major research approach used in this research is social network analysis (SNA), together with methodologies employed in design science research. The contribution of our research includes: (i) a faceted model to categorize social bookmarking tags; (ii) a relationship ontology to represent the semantics of relationships between tags; (iii) heuristics to reorganize the flat tag space into a hierarchical faceted model using analysis of tag-tag co-occurrence networks; (iv) an implemented prototype system as proof-of-concept to validate the feasibility of the reorganization approach; (v) a set of evaluations of the social functions of the current networking features of social bookmarking and a series of recommendations as to how to improve the social functions to facilitate web content discovery.
13

EXPLORING WAYS TO VISUALIZE NEWS OVER GEOGRAPHICAL MAPS

Salimian Rizi, Mohamad Hossein 16 August 2012 (has links)
Online news sites are some of the most useful and popular information retrieval systems in use today. Thousands of articles in different languages and on a variety of subjects are posted every day and updated every hour. Most articles are uninteresting and unimportant to a particular individual, and individuals may not want to review entire websites for stories of interest. Systems have been developed that provide summaries from online news websites but finding a means to rapidly scan stories of potential interest remains an open problem. In this thesis, we introduce a novel visualization system that uses geographical location combined with image collages and tag clouds to provide a tool for rapidly reviewing news stories. Tag clouds are arrangements of tags with the most important tags allocated a bigger font size or otherwise more prominent visual properties; and image collages provide a compact, effective and attractive representation for photos on one page. Bringing these media representations together over a geographic map offers a new style of interaction for online news browsing. The usability of our application was evaluated with two user studies. We aimed to determine how best to configure our visualization to communicate more information in less time to users than traditional feed-based news aggregators. We were particularly interested in knowing whether users interpret text/image size and placement as indications of a news item’s prominence. We also wanted to establish whether users understand the semantic relationship between zoom level on the map and the regional relevance (municipal, provincial, national) of news items displayed at that zoom level. The results of user feedback and data analysis (e.g., eye tracking logs) were examined to improve the usability of the system. Data analysis from the second user study suggests that, in general, the system is highly effective in helping users achieve an immediate and effortless bird’s-eye-view of news summaries within a large geographic region. However, users had varying opinions about the level of detail in the user interface (e.g., the number of images).
14

Towards Folksonomy-based Personalized Services in Social Media

Rawashdeh, Majdi 30 April 2014 (has links)
Every single day, lots of users actively participate in social media sites (e.g., Facebook, YouTube, Last.fm, Flicker, etc.) upload photos, videos, share bookmarks, write blogs and annotate/comment on content provided by others. With the recent proliferation of social media sites, users are overwhelmed by the huge amount of available content. Therefore, organizing and retrieving appropriate multimedia content is becoming an increasingly important and challenging task. This challenging task led a number of research communities to concentrate on social tagging systems (also known as folksonomy) that allow users to freely annotate their media items (e.g., music, images, or video) with any sort of arbitrary words, referred to as tags. Tags assist users to organize their own content, as well as to find relevant content shared by other users. In this thesis, we first analyze how useful a folksonomy is for improving personalized services such as tag recommendation, tag-based search and item annotation. We then propose two new algorithms for social media retrieval and tag recommendation respectively. The first algorithm computes the latent preferences of tags for users from other similar tags, as well as latent annotations of tags for items from other similar items. We then seamlessly map the tags onto items, depending on an individual user’s query, to find the most desirable content relevant to the user’s needs. The second algorithm improves tag-recommendation and item annotation by adapting the Katz measure, a path-ensemble based proximity measure, for the use in social tagging systems. In this algorithm we model folksonomy as a weighted, undirected tripartite graph. We then apply the Katz measure to this graph, and exploit it to provide personalized tag recommendation for individual users. We evaluate our algorithms on two real-world folksonomies collected from Last.fm and CiteULike. The experimental results demonstrate that the proposed algorithms improve the search and the recommendation performance, and obtain significant gains in cold start situations where relatively little information is known about a user or an item
15

Towards Folksonomy-based Personalized Services in Social Media

Rawashdeh, Majdi January 2014 (has links)
Every single day, lots of users actively participate in social media sites (e.g., Facebook, YouTube, Last.fm, Flicker, etc.) upload photos, videos, share bookmarks, write blogs and annotate/comment on content provided by others. With the recent proliferation of social media sites, users are overwhelmed by the huge amount of available content. Therefore, organizing and retrieving appropriate multimedia content is becoming an increasingly important and challenging task. This challenging task led a number of research communities to concentrate on social tagging systems (also known as folksonomy) that allow users to freely annotate their media items (e.g., music, images, or video) with any sort of arbitrary words, referred to as tags. Tags assist users to organize their own content, as well as to find relevant content shared by other users. In this thesis, we first analyze how useful a folksonomy is for improving personalized services such as tag recommendation, tag-based search and item annotation. We then propose two new algorithms for social media retrieval and tag recommendation respectively. The first algorithm computes the latent preferences of tags for users from other similar tags, as well as latent annotations of tags for items from other similar items. We then seamlessly map the tags onto items, depending on an individual user’s query, to find the most desirable content relevant to the user’s needs. The second algorithm improves tag-recommendation and item annotation by adapting the Katz measure, a path-ensemble based proximity measure, for the use in social tagging systems. In this algorithm we model folksonomy as a weighted, undirected tripartite graph. We then apply the Katz measure to this graph, and exploit it to provide personalized tag recommendation for individual users. We evaluate our algorithms on two real-world folksonomies collected from Last.fm and CiteULike. The experimental results demonstrate that the proposed algorithms improve the search and the recommendation performance, and obtain significant gains in cold start situations where relatively little information is known about a user or an item
16

Polymères à empreintes moléculaires : nouveaux outils prometteurs pour la synthèse organique / Molecularly imprinted polymers : new promising tools for organic sysnthesis

Le Foll, Alexandra 19 March 2010 (has links)
Le projet présenté dans ce manuscrit consiste à utiliser la technologie des polymères à empreintes moléculaires (MIPs) pour concevoir de nouveaux outils pour la synthèse organique. Dans un premier temps, nous nous sommes intéressés à l'étude du potentiel des MIPs en organocatalyse, par l'intermédiaire d'une activation entropique dans les empreintes. Pour cela, plusieurs organocatalyseurs de type quinine thiourée ont été synthétisés afin d'être intégrés dans les cavités du polymère. Malgré l'efficacité de l'impression montrée en HPLC, aucun effet bénéfique sur la vitesse ou l'énantiosélectivité de la réaction n'a pu être mis en évidence par l'utilisation des différents MIPs synthétisés dans la catalyse de la réaction de Henry. Dans un second temps, nous avons développé une stratégie de séparation efficace et applicable à une large gamme de composés en utilisant la technologie des MIPs associées à celle des tags. Notre tag a été formé par réaction de "chimie click" générant ainsi un groupement triazole reconnaissable par un MIP-Tag. Après avoir montré l'efficacité et la sélectivité du MIP-Tag pour une famille de triazoles, l'extraction sélective de la tyrosine taggée d'un mélange d'acides aminés a été réalisée avec une très bonne sélectivité. Par la suite, l'application de notre procédé au recyclage de catalyseurs dérivés de pybox et de proline a été étudiée. Enfin, nous avons montré l'efficacité de notre méthode pour l'élimination de l'oxyde de triphénylphosphine lors d'une réaction de Mitsunobu. La purification d'un milieu réactionnel en SPE au moyen du MIP-Tag a permis l'élimination de 99% de l'oxyde de triphénylphosphine taggé. / This work deals with the use of molecular imprinting technology for the design of new tools in organic sythesis. First, we studied the potential of MIPs in organocatalysis through activation in the imprints. For this purpose, several thiourea-cinchona alkaloid derivatives have been prepared so as to be introduced in the polymer cavities. The use of different MIPs synthesised with these polymerisable catalysts in Henry reaction did not show any advantageous effect on reaction rate or enantioselectivity. Secondly, we have prformed the development of a strategy for separation and recovery of a wide range of compounds by relating tag technology with molecular imprinting. Efficiency and selectivity of MIP-Tag for in triazole series have been demonstrated. Tagged tyrosine has been selectively extracted from an amino-acid mixture. Then, the application of this Tag technology for the recovery of pybox and proline catalyst was investigated. Finally, we have demonstrated the efficiency of our process for the removal of triphenylphosphine oxide formed during a Mitsunobu reaction. The removal of 99% of tagged phosphine oxide was perforrmed by the purification of a reaction medium in SPE by means of MIP-Tag.
17

RFID Tag Design and Range Improvement

Chirammal Ramakrishnan, Rijwal January 2012 (has links)
Radio Frequency Identification (RFID) is a short range radio technology for communication between two objects namely, a reader and a tag. Design of an RFID tag with the best range is always the motive of an RFID designer. In this thesis two RFID tags were simulated, designed and manufactured. The first one is a semi-passive RFID tag, which also serves as a discrete prototype tag for the research group to master RFID tag designs. The user can program and further extend the use of this tag according to the requirements. This RFID tag is provided with JTAG interface to program and debug. The read range of this prototype tag is found to be 1m with reader EIRP of 30dBm. The second design is a passive tag which can be commercialized. It achieves a competitive read range of 2.9m for reader EIRP of 21dBm. The read range when measured in a practical implementation inside a building corridor was 15m.
18

PTAG - aktiv RFID-tag med GPS

Bengtsson, Christofer, Madsen, Kristoffer January 2008 (has links)
<p>Free2Move AB is developing products for the market within wireless communication</p><p>and identification, among those active RFID-tags. The company had an idea about</p><p>providing one of their active RFID tags with a GPS receiver and transmit positions via</p><p>an existing RFID protocol. Desire from the company was also the possibility to log</p><p>positions and measure temperature. The finished prototype should also be able to be</p><p>activated by movement. The company had proposal about components that were to be</p><p>used in the project. A large part of the work was to understand how these worked and</p><p>how to combine them to fulfill the requirements established in agreement with</p><p>supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype</p><p>and software implemented for communication with GPS, RFID tag and other</p><p>components. The result was a working prototype where an existing RFID tag was</p><p>integrated in the same printed circuit board layout as the GPS receiver and other</p><p>components that were used in the project.</p>
19

Design of RFID Tag Antenna with High Impedance Surface Structure to Reduce Metallic Effect

Tsai, Wei-Kuo 20 June 2006 (has links)
In this study, we design and fabricate novel tag antennas, which can be used on the metallic surface for radio frequency identification systems. We first focus on the effects when the antenna is placed on the metallic surface. Based on the simulation results, we investigate how the parameters of the antennas are affected. The helps us find solutions to reduce the effects when the antennas are placed on the metallic surface. In order to conform to the IC chips of RFID and reduce the influence of metal objects, we use the structure of the dipole antenna is used as the basis of the novel tag antenna design. And we employ the high impedance surface periodic structure which behaves similarly to a perfect magnetic conductor in the design of the novel tag antenna. The novel tag antenna is able to work normally when it was attached on the surface of the carton or metallic object. Finally, the tag antenna is fabricated and measured in a chamber. The measured results agree with simulated ones well.
20

Study on the production process of the recombinant his-tag streptavidin

Huang, Chi-tien 14 February 2008 (has links)
In this study, we used E. coli strain BL21 (DE3) to express the recombinant protein his-tag streptavidin. To find out the optimal production conditions, we studied on the culture conditions, medium composition, induction conditions and the timing of induction. In the purification processes we tried to find out the difference between hydrophobic column and affinity column. We also tested the effect of heat treatment on the crude extract to increase the recombinant protein yield. The results showed that when cultured in LB medium, the optimal culture conditions of recombinant protein expression are 37¢XC, pH 6.0 to 7.0, and the induction temperature is 37¢XC. The best induction time is at late log phase or the early stationary phase when OD600 values reached to the ranged of 1.1 to 1.8. The inducer, IPTG concentration is 0.1 mM, which can also replaced with 2 mM lactose. The best production medium is TB medium. When cultured in 5 liters fermentor with optimal culture and induction condition, the highest recombinant protein yield could be 81.1 mg /L. To improve the purification process, we used a affinity chromatography. The purified high homogeneous recombinant protein had a high biotin binding activity up to 14 U / mg, and the recovery yield could be as high as 97% in comparing with the hydrophobic column was only 51%. When we treated the crude extract with 75 ¢J for 10 min, the biotin binding activity was 14.1 U / mg, but the recovery rate decreased to 64 %.

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