43818812
Piecewise linear modulation model of handwriting
A new piecewise linear modulation model of handwriting is proposed. In this model, the velocity of handwriting trajectory is modeled as the impulse response of a time varying second order system. For mathematical tractability, the entire trajectory is segmented into several non-overlapping frames, while the natural frequency and the damping factor of the system are assumed to vary linearly with time in each frame and are continuous along the entire trajectory. In other words, handwriting is regarded as an oscillation modulated by a continuous and piecewise linear signal. The parameters of this model are estimated by Powell's optimization algorithm which does not require the computation of the first order derivative. The number and lengths of the frames are decided by a modified binary search algorithm along with the estimation of parameters. This model has achieved very high data compression rate as well as accurate reproduction of real handwriting.
9507980
Using build-integrated static checking to preserve correctness invariants
A key missing link in the creation of secure and robust systems is finding a ost effective way to demonstrate and preserve correspondence between a software design and its implementation. This paper explores the use of software model checking techniques to validate selected design invariants in the EROS operating system kernel. Several global consistency policies in the EROS kernel can be expressed as finite state automata. Using the MOPS static hecker, we have been able to validate the EROS kernel implementation against these automata. In the process, we have confirmed the practical utility of the basic verification technique, identified a number of desirable enhancements in MOPS, and located bugs in the EROS implementation.
 A key contribution of this paper is establishing that it is practical to integrate software model checking into normal development lifestyle. Model hecking is efficient enough that it does not add noticeably to our build times. This allows us to view it as a tool for error prevention rather than <i>detection</i>. Our work with EROS and MOPS suggests that domain specific application of software model hecking is a practical and powerful technique for software assurance and maintenance.
14045822
Optimizing search by showing results in context
We developed and evaluated seven interfaces for integrating semantic category information with Web search results. List interfaces were based on the familiar ranked-listing of search results, sometimes augmented with a category name for each result. Category interfaces also showed page titles and/or category names, but re-organized the search results so that items in the same category were grouped together visually. Our user studies show that all Category interfaces were more effective than List interfaces even when lists were augmented with category names for each result. The best category performance was obtained when both category names and individual page titles were presented. Either alone is better than a list presentation, but both together provide the most effective means for allowing users to quickly examining search results. These results provide a better understanding of the perceptual and cognitive factors underlying the advantage of category groupings and provide some practical guidance to Web search interface designers.
1567676
Bringing order to the Web: automatically categorizing search results
We developed a user interface that organizes Web search results into hierarchical categories. Text classification algorithms were used to automatically classify arbitrary search results into an existing category structure on-the-fly. A user study compared our new category interface with the typical ranked list interface of search results. The study showed that the category interface is superior both in objective and subjective measures. Subjects liked the category interface much better than the list interface, and they were 50% faster at finding information that was organized into categories. Organizing search results allows users to focus on items in categories of interest rather than having to browse through all the results sequentially.
9059456
Model Checking One Million Lines of C Code
Implementation bugs in security-critical software are pervasive. Several authors have previously suggested model checking as a promising means to detect improper use of system interfaces and thereby detect a broad class of security vulnerabilities. In this paper, we report on our practical experience using MOPS, a tool for software model checking security-critical applications. As examples of security vulnerabilities that can be analyzed using model checking, we pick five important classes of vulnerabilities and show how to codify them as temporal safety properties, and then we describe the results of checking them on several significant Unix applications using MOPS. After analyzing over one million lines of code, we found more than a dozen new security weaknesses in important, widely-deployed applications. This demonstrates for the first time that model checking is practical and useful for detecting security weaknesses at large scale in real,
2098964
Spam double-funnel: connecting web spammers with advertisers
Spammers use questionable search engine optimization (SEO) techniques to promote their spam links into top search results. In this paper, we focus on one prevalent type of spam - redirection spam - where one can identify spam pages by the third-party domains that these pages redirect traffic to. We propose a five-layer, double-funnel model for describing end-to-end redirection spam, present a methodology for analyzing the layers, and identify prominent domains on each layer using two sets of commercial keywords. one targeting spammers and the other targeting advertisers. The methodology and findings are useful for search engines to strengthen their ranking algorithms against spam, for legitimate website owners to locate and remove spam doorway pages, and for legitimate advertisers to identify unscrupulous syndicators who serve ads on spam pages.
16942431
A graph model for E-commerce recommender systems
Information overload on the Web has created enormous challenges to customers selecting products for online purchases and to online businesses attempting to identify customers' preferences efficiently. Various recommender systems employing different data representations and recommendation methods are currently used to address these challenges. In this research, we developed a graph model that provides a generic data representation and can support different recommendation methods. To demonstrate its usefulness and flexibility, we developed three recommendation methods: direct retrieval, association mining, and high-degree association retrieval. We used a data set from an online bookstore as our research test-bed. Evaluation results showed that combining product content information and historical customer transaction information achieved more accurate predictions and relevant recommendations than using only collaborative information. However, comparisons among different methods showed that high-degree association retrieval did not perform significantly better than the association mining method or the direct retrieval method in our test-bed.
13392863
A Smart Itsy Bitsy Spider for the Web
As part of the ongoing Illinois Digital Library Initiative are expected to worsen as the amount of online informaproject, this research proposes an intelligent agent aption increases. This is mainly due to the problems of proach to Web searching. In this experiment, we develinformation overload and vocabulary differences (Chen, oped two Web personal spiders based on best first 1994; Furnas, Landauer, Gomez, & Dumais, 1987). search and genetic algorithm techniques, respectively. Many researchers consider that devising a scalable apThese personal spiders can dynamically take a user’s selected starting homepages and search for the most proach to Web search is critical to the success of Internet closely related homepages in the Web, based on the and Intranet services, and other current and future Nalinks and keyword indexing. A graphical, dynamic, Javational Information Infrastructure (NII) applications based interface was developed and is available for Web (Chen & Schatz, 1994; Schatz & Chen, 1996). access. A system architecture for implementing such an The main information retrieval mechanisms provided agent-based spider is presented, followed by detailed discussions of benchmark testing and user evaluation by the prevailing Internet WWW-based software are results. In benchmark testing, although the genetic algobased on either keyword search (e.g., Lycos, Alta Vista, rithm spider did not outperform the best first search spiand Yahoo servers) or hypertext browsing (e.g., NCSA der, we found both results to be comparable and comMosaic, Netscape Navigator, and Microsoft Internet Explementary. In user evaluation, the genetic algorithm spiplorer) . Keyword search often results in low precision, der obtained significantly higher recall value than that of the best first search spider. However, their precision poor recall, and slow response time because of the limitavalues were not statistically different. The mutation protions of indexing and communication methods (bandcess introduced in genetic algorithm allows users to find width) , controlled language-based interfaces (the vocabother potential relevant homepages that cannot be exulary problem), and the inability of searchers themselves plored via a conventional local search process. In addition, we found the Java-based interface to be a necesto fully articulate their needs. Furthermore, browsing sary component for design of a truly interactive and dyallows users to explore only a very small portion of the namic Web agent. large Web information space. An extensive information
53306841
Dental Biometrics: Alignment and Matching of Dental Radiographs
Dental biometrics utilizes dental radiographs for human identification. The dental radiographs provide information about teeth, including tooth contours, relative positions of neighboring teeth, and shapes of the dental work (e.g., crowns, fillings, and bridges). The proposed system has two main stages: feature extraction and matching. The feature extraction stage uses anisotropic diffusion to enhance the images and a mixture of Gaussians model to segment the dental work. The matching stage has three sequential steps: tooth-level matching, computation of image distances, and subject identification. In the tooth-level matching step, tooth contours are matched using a shape registration method and the dental work is matched on overlapping areas. The distance between the tooth contours and the distance between the dental works are then combined using posterior probabilities. In the second step, the tooth correspondences between the given query (postmortem) radiograph and the database (antemortem) radiograph are established. A distance based on the corresponding teeth is then used to measure the similarity between the two radiographs. Finally, all the distances between the given postmortem radiographs and the antemortem radiographs that provide candidate identities are combined to establish the identity of the subject associated with the postmortem radiographs.
16294852
Interactive volume visualization on a heterogeneous message-passing multicomputer
This paper describes VOL2, an interactive general-purpose volume renderer based on ray casting and implemented on Pixel-Planes 5, a distributed-memory, message-passing multicomputer. VOL2 is a pipelined renderer using image-space task parallelism and object-space data partitioning. We describe the parallelization and load balancing techniques used in order to achieve interactive response and near-real-time frame rates. We also present a number of applications for our system and derive some general conclusions about operation of image-order rendering algorithms on message-passing multicomputers.
10299300
On the development of a fully automated cryosection image registration system
The CCD cryosection images for the male collected in the National Library of Medicine's Visible Human Project were registered through a procedure involving significant human intervention. In addition, several large misalignments were visible in the registered CCD data for the male. To expedite the exploitation of the visible human cryosection data sets, there is a need to develop a highly accurate yet efficient image registration tool. In this paper, we present the current status of the development of such a fully automated registration system. This system is based on the maximization of mutual information criterion. One key issue of this approach is a robust optimization scheme. The method developed in this paper is to estimate the initial search point through segmentations of regions of interest for each cryosection image slice. Experimental results using the 70 mm cryosection image data for the male are presented in this paper.