11840547
Numerical Analysis Of The Edl Effect On Liquid Flow In Microchannels
A mathematical model is developed to study the electrokinetic effect on developing liquid flow in a parallel slit. A finite-volume method is used to solve the proposed model. The characteristics of the pressure-driven flow in the presence of the electrokinetic effect are examined. The computation results show the electrical double layer has the effect on both developing and fully-developed flows.
45339788
Fabrication Of Concave And Convex Micro-Optical Elements With Polymer For Free-Space Micro-Optical Bench
The development of micro-optical bench (MOB) technology as so far been limited by its reliance on polysilicon based elements which does not have good optical properties, and does not easily yield the spherical surfaces needed for refracting lenses. Polymers have shown large improvement in the recent years and could be a solution to hasten the development of MOB. We report here on the fabrication using polymers of converging and diverging refracting lens, with diameter ranging between 60 μm and 500 μm and with focal length as small as 100 μm. The polymer investigated where a photosensible cresol novolak (AZ9260), a photosensible epoxy resin (SU8) and a silicone (PDMS). In addition we have developed a phenomenological model and a physical model that elucidate the relationship between the fabrication parameters and the characteristics of the optical elements.
33160619
Characterization Of Electroosmotic Flow In Microchannels
This paper presents experimental and theoretical studies of the electroosmotic flow in microchannels. The current monitoring method is used to determine the average flow velocity and the ζ potential by measuring the current-time relationship during electrolyte displacement process. A rigorous mathematical model is developed to describe the electrokinetic transport phenomena in such displacement process. Experiments were carried out for the NaCl electrolyte to evaluate the electroosmotic velocity and the ζ potential under various experimental conditions. The theoretical predictions for the current-time relationship are compared with measured results.
28993382
Algebraic Sub-structuring for Electromagnetic Applications
Algebraic sub-structuring refers to the process of applying matrix reordering and partitioning algorithms to divide a large sparse matrix into smaller submatrices from which a subset of spectral components are extracted and combined to form approximate solutions to the original problem. In this paper, we show that algebraic sub-structuring can be effectively used to solve generalized eigenvalue problems arising from the finite element analysis of an accelerator structure.
16166999
Automatic Construction of Cross-Lingual Networks of Concepts from the Hong Kong SAR Police Department
The tragic event of September 11 has prompted the rapid growth of attention of national security and criminal analysis. In the national security world, very large volumes of data and information are generated and gathered. Much of this data and information written in different languages and stored in different locations may be seemingly unconnected. Therefore, cross-lingual semantic interoperability is a major challenge to generate an overview of this disparate data and information so that it can be analysed, searched. The traditional information retrieval (IR) approaches normally require a document to share some keywords with the query. In reality, the users may use some keywords that are different from what used in the documents. There are then two different term spaces, one for the users, and another for the documents. The problem can be viewed as the creation of a thesaurus. The creation of such relationships would allow the system to match queries with relevant documents, even though they contain different terms. Apart from this, terrorists and criminals may communicate through letters, e-mails and faxes in languages other than English. The translation ambiguity significantly exacerbates the retrieval problem. To facilitate cross-lingual information retrieval, a corpusbased approach uses the term co-occurrence statistics in parallel or comparable corpora to construct a statistical translation model to cross the language boundary. However, collecting parallel corpora between European language and Oriental language is not an easy task due to the unique linguistics and grammar structures of oriental languages. In this paper, the text-based approach to align English/Chinese Hong Kong Police press release documents from the Web is first presented. This article then reports an algorithmic approach to generate a robust knowledge base based on statistical correlation analysis of the semantics (knowledge) embedded in the bilingual press release corpus. The research output consisted of a thesaurus-like, semantic network knowledge base, which can aid in semantics-based cross-lingual information management and retrieval.
39460490
Localization Techniques for Cluster-Based Data Grid
In this paper, we present an efficient method for optimizing localities of data distribution when executing data parallel applications. The data to logical grid nodes mapping technique is employed to enhance the performance of parallel programs on cluster grid. Cluster grid is a typical computational grid environment consists of several clusters located in multiple campuses that are distributed globally over the Internet. Objective of the proposed technique is to reduce inter-cluster communication overheads and to speed the execution of data parallel programs in the underlying distributed cluster grid. The theoretical analysis and experimental results show improvement of communication costs and scalable of the proposed techniques on different hierarchical cluster grids.
9223359
Image browsing for infomediaries
Information intermediary or infomediary is likely to claim a major segment of the revenue of e-commerce transactions. Infomediaries are e-commerce companies leveraging the Internet to unite buyers and suppliers in a single efficient virtual marketplace to facilitate the consummation of a transaction. Most of the search facilities in the infomediaries are text- and navigation-based, for example by keyword and category searches. The search facility can handle most of the products, but it is inefficient to handle feature-based products, such as textile and shoes with different colors and textures. It will be difficult for buyers to speck searches of feature-based products in describing the product features and characteristics. For example, it is hot easy to describe the pattern and color of a T-shirt using textural expression. In this paper, we propose an image browsing technique to facilitate search of feature-based products for infomediaries. We implemented an image-based retrieval system with the proposed image browsing technique for textile industrial and evaluated the performance of the browsing technique.
636423
Visualization of large category map for Internet browsing
Information overload is a critical problem in World Wide Web. Category map developed based on Kohonen's self-organizing map (SOM) has been proven to be a promising browsing tool for the Web. The SOM algorithm automatically categorizes a large Internet information space into manageable sub-spaces. It compresses and transforms a complex information space into a two-dimensional graphical representation. Such graphical representation provides a user-friendly interface for users to explore the automatically generated mental model. However, as the amount of information increases, it is expected to increase the size of the category map accordingly in order to accommodate the important concepts in the information space. It results in increasing of visual load of the category map. Large pool of information is packed closely together on a limited size of displaying window, where local details are difficult to be clearly seen. In this paper, we propose the fisheye views and fractal views to support the visualization of category map. Fisheye views are developed based on the distortion approach while fractal views are developed based on the information reduction approach. The purpose of fisheye views are to enlarge the regions of interest and diminish the regions that are further away while maintaining the global structure. On the other hand, fractal views are an approximation mechanism to abstract complex objects and control the amount of information to be displayed. We have developed a prototype system and conducted a user evaluation to investigate the performance of fisheye views and fractal views. The results show that both fisheye views and fractal views significantly increase the effectiveness of visualizing category map. In addition, fractal views are significantly better than fisheye views but the combination of fractal views and fisheye views do not increase the performance compared to each individual technique.