ppxscal/embedding_network huggingface dataset:
Attribute grammars for unranked trees as a query language for structured documents
Authors: Frank Neven
Venue: Journal of Computer and System Sciences (2005)

Document specification languages, like for instance XML, model documents using extended context-free grammars. These differ from standard context-free grammars in that they allow arbitrary regular expressions on the right-hand side of productions. To query such documents, we introduce a new form of attribute grammars (extended AGs) that work directly over extended context-free grammars rather than over standard context-free grammars. Viewed as a query language, extended AGs are particularly relevant as they can take into account the inherent order of the children of a node in a document. We show that non-circularity remains decidable in EXPTIME and establish the complexity of the non-emptiness and equivalence problem of extended AGs to be complete for EXPTIME. As an application we show that the Region Algebra expressions can be efficiently translated into extended AGs. This translation drastically improves the known upper bound on the complexity of the emptiness and equivalence test for Region Algebra expressions from non-elementary to EXPTIME. Finally, we characterize the expressiveness of extended AGs in terms of monadic second-order logic.
Compressed shadow maps
Authors: Jukka Arvo, Mika Hirvikorpi
Venue: The Visual Computer: International Journal of Computer Graphics (2005)

Shadow mapping has been subject to extensive investigation, but previous shadow map algorithms cannot usually generate high-quality shadows with a small memory footprint. In this paper, we present compressed shadow maps as a solution to this problem. A compressed shadow map reduces memory consumption by representing lit surfaces with endpoints of intermediate line segments as opposed to the conventional array-based pixel structures. Compressed shadow maps are only discretized in the vertical direction while the horizontal direction is represented by floating-point accuracy. The compression also helps with the shadow map self-shadowing problems. We compare our algorithm against all of the most popular shadow map algorithms and show, on average, order of magnitude improvements in storage requirements in our test scenes. The algorithm is simple to implement, can be added easily to existing software renderers, and lets us use graphics hardware for shadow visualization.
Multiple Object Tracking with Kernel Particle Filter
Authors: Cheng Chang, Rashid Ansari, Ashfaq Khokhar
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 1 - Volume 01 (2005)

A new particle filter, Kernel Particle Filter (KPF), is proposed for visual tracking for multiple objects in image sequences. The KPF invokes kernels to form a continuous estimate of the posterior density function and allocates particles based on the gradient derived from the kernel density estimate. A data association technique is also proposed to resolve the motion correspondence ambiguities that arise when multiple objects are present. The data association technique introduces minimal amount of computation by making use of the intermediate results obtained in particle allocation. We show that KPF performs robust multiple object tracking with improved sampling efficiency.
Addressing Radiometric Nonidealities: A Unified Framework
Authors: Anatoly Litvinov, Yoav Y. Schechner
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 2 - Volume 02 (2005)

Cameras may have non-ideal radiometric aspects, including spatial non-uniformity, e.g., due to vignetting; nonlinear radiometric response of the sensor; and temporal variations due to automatic gain control (AGC). Often, these characteristics exist simultaneously, and are typically unknown. They thus hinder consistent photometric-measurements. In particular, they create annoying seams in image mosaics. Prior studies approached part of these problems while excluding others. We handle all these problems a unified framework. We suggest an approach for simultaneously estimating the radiometric response, the spatial non-uniformity and the temporally varying gain. The approach does not rely on dedicated processes that intentionally vary exposure settings. Rather, it is based on an ordinary frame sequence acquired during camera motion. The estimated non-ideal characteristics are then compensated for. We state fundamental ambiguities associated with this recovery problem, while exposing a novel image invariance. The method is demonstrated in several experiments, where different frames are brought into mutual radiometric consistency. The accuracy achieved is sufficient for seamless mosaicing, with no need to resort to dedicated seam-feathering methods.
Spanning Large Workspaces Using Small Haptic Devices
Authors: Francois Conti, Oussama Khatib
Venue: Proceedings of the First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2005)

Exploring large virtual environments using a small haptic device with limited-workspace capabilities is a challenging task because the user very quickly reaches the borders of the physical workspace of the device. In the case of a computer mouse, this problem is solved by lifting the device off the table and repositioning it at a different location. With most ground-based haptic devices such indexing procedure is not possible and requires the use of an additional switch to decouple the device from the cursor and allow the user to relocate the end-effector at the center of the physical workspace. Below certain physical workspace dimensions such indexing methods become cumbersome to the operator and therefore different control paradigms are required. This paper presents a new approach referred to as Workspace Drift Control which progressively relocates the physical workspace of the device mapped inside the virtual environment towards the area of interest of the operator without disturbing his or her perception of the environment. This technique uses the fact that people are greatly influenced by what they perceive visually and often do not notice small deviations of their hand unless that small deviation has a corresponding visual component.
On the complexity of computing determinants
Authors: Erich Kaltofen, Gilles Villard
Venue: Computational Complexity (2005)

We present new baby steps/giant steps algorithms of asymptotically fast running time for dense matrix problems. Our algorithms compute the determinant, characteristic polynomial, Frobenius normal form and Smith normal form of a dense n × n matrix A with integer entries in $$\left( {n^{3.2} \log \left\| A \right\|} \right)^{1 + o(1)} $$ and $$\left( {n^{2.697263} \log \left\| A \right\|} \right)^{1 + o(1)} $$ bit operations; here $$\left\| A \right\|$$ denotes the largest entry in absolute value and the exponent adjustment by "+o(1)" captures additional factors $$C_1 (\log n)^{C_2 } \left( {\log \log \left\| A \right\|} \right)^{C_3 } $$ for positive real constants C1, C2, C3. The bit complexity $$\left( {n^{3.2} \log \left\| A \right\|} \right)^{1 + o(1)} $$ results from using the classical cubic matrix multiplication algorithm. Our algorithms are randomized, and we can certify that the output is the determinant of A in a Las Vegas fashion. The second category of problems deals with the setting where the matrix A has elements from an abstract commutative ring, that is, when no divisions in the domain of entries are possible. We present algorithms that deterministically compute the determinant, characteristic polynomial and adjoint of A with n3.2+o(1) and O(n2.697263) ring additions, subtractions and multiplications.
Performance of Multiple High Altitude Platforms using Directive HAP and User Antennas
Authors: Guanhua Chen, David Grace, Tim C. Tozer
Venue: Wireless Personal Communications: An International Journal (2005)

This paper examines the behaviour of system capacity in High Altitude Platform (HAP) communications systems as a function of antenna directivity and HAP positioning. Antenna models for the user and the HAP are discussed, and it is shown that a flat sidelobe antenna pattern is suitable for modelling multiple HAP constellations when HAPs are located outside the coverage area. Using a single HAP scenario it is shown how narrowing the HAP antenna beamwidth may give better downlink Carrier-to-Noise Ratio (CNR) over the most of the coverage area. The roles of the HAP antenna beamwidth, HAP antenna pointing and HAP spacing radius are investigated. An equation is derived to determine the location of the peak CNR combined with these three parameters. A more complex multiple HAP scenario where all HAP's operate on the same channel and interfere with each other is also assessed in terms of the Carrier to Interference plus Noise Ratio (CINR) and spectral efficiency. It is shown that locating HAPs at a specific spacing radius that is outside the coverage area can improve performance. Using these techniques the combined bandwidth efficiency is shown to increase almost pro-rata when the number of HAPs is increased up to 16.
Conceptual framework for tasks in information studies: Book Reviews
Authors: Katriina Byström, Preben Hansen
Venue: Journal of the American Society for Information Science and Technology (2005)

Today information-intensive work tasks in professional settings involve highly dynamic information utilization in which information seeking and searching tasks are taking a more central role. This article considers the concept of task in the context of information studies in order to provide a definitional clarity for task-based information seeking and retrieval studies. We identify (1) the central task levels as well as (2) the kinds of dimensions connected to the levels from the perspective of information studies. The analysis is aimed to serve as a conceptual starting point for empirical studies in the research area. The focus is on some central aspects of tasks that are recognized within information studies as well as related research areas (e.g., organizational studies). We define two levels of information-related subtasks: information seeking tasks and information search tasks. Information retrieval tasks are explicitly considered as a specific type of information search task. We describe differences and connections between these task levels. Finally, the implications of the proposed conceptual framework for information studies are discussed. &copy; 2005 Wiley Periodicals, Inc.
Evaluation and optimization of method calls in Java
Authors: Francesco Bellotti, Riccardo Berta, Alessandro De Gloria
Venue: Software&mdash;Practice Experience (2004)

Recent advances in Virtual Machine's technology have led to the diffusion of Java execution environments which provide performance levels comparable to those of traditional languages such as C&sol;C&plus;&plus; and Fortran. This paper's focus is on method calls, a well researched area of compilers' optimization. In particular, we evaluate the impact on the performance of the Java virtual call mechanism and the advantages which can be obtained through the inlining optimization. Moreover, we propose a new heuristic methodology which allows us to consider whole sequences of methods for the inlining decision and not only simple couples of caller&ndash;callee methods.The proposed methodology operates at bytecode level and is applicable only to the calls that can be resolved at compile time. Thus, we execute a devirtualization algorithm before the inlining decision, in order to enlarge the basis for the optimization.We made empirical measures on three major platforms &lpar;Unix, Windows and Linux&rpar; by using the SPEC JVM98 benchmark suite. Results reveal an average performance improvement of 1.9&percnt; with devirtualization and 5.5&percnt; with inlining. We discuss the different behaviour of single benchmarks and virtual machines, arguing that dynamic compilers are not yet able to fully exploit the wider scope for intra-procedural optimization offered by eliminating the calls. Finally, we show that taking into consideration whole sequences of calls&mdash;instead of single calls&mdash;is effective only on a few benchmarks where hotspots of execution involve cycles of nested methods. Copyright &copy; 2003 John Wiley & Sons, Ltd.
Classification Ensembles for Shaft Test Data: Empirical Evaluation
Authors: Kyungmi Lee, Vladimir Estivill-Castro
Venue: Proceedings of the Fourth International Conference on Hybrid Intelligent Systems (2004)

A-scans from ultrasonic testing of long shafts are complex signals. The discrimination of different types of echoes is of importance for non-destructive testing and equipment maintenance. Research has focused on selecting features of physical significance or exploring classifier like Artificial Neural Networks and Support Vector Machines. This paper confirms the observation that there seems to be uncorrelated errors among the variants explored in the past, and therefore an ensemble of classifiers is to achieve better discrimination accuracy. We explore the diverse possibilities of heterogeneous and homogeneous ensembles, combination techniques, feature extraction methods and classifiers types and determine guidelines for heterogeneous combinations that result in superior performance.
The Corona Project: a testing framework for programming contests
Authors: Stephen D. Gewand, Greta Q. Heissenberger
Venue: Journal of Computing Sciences in Colleges (2004)

Every year, approximately 40 teams of high school students compete in an annual high school programming contest at St. Bonaventure University. The students' solutions are fed a standard set of secret test data, allowed to run, and judged solely upon their output. In the past, judges of the programming contest have had to enter test data for each of the individual solutions and manually compare the program's output to the correct answers. This method requires a good deal of time and manpower. The Corona Project automates this process. This will improve the accuracy of judging and allow judging to be done by the students themselves without revealing the test data. Additionally, high school computer science teachers will be able to utilize Corona to grade student's assignments, and students will be able to test their solutions as they are developed.
Natural Language programming: Duke University
Authors: Alan W. Biermann, Bruce W. Ballard, Pamela K. Fink, Robert Rodman, David Rubin
Venue: Issue 79 (January 1982) (1982)

This project concentrates on the fast, efficient execution of sequences of imperative sentences for a variety of applications. The general strategy assumes that the machine controls a world of interest to the user which can be observed on a computer display screen. The user inputs sentences requesting actions to be performed on the world and observes the result of each command. If the result does not satisfy the user, he or she may request a back-up and rephase the command in clearer language. Most commands are executed in about 2 to 4 seconds making it possible to have a genuine dialog in real time in the solution of real problems.
Mining for data and personal privacy: reflections on an impasse
Authors: Ioannis-Evangelos Papasliotis
Venue: Proceedings of the 4th international symposium on Information and communication technologies (2005)

Data mining, also know as 'knowledge discovery in databases', is a technique that enables the user to find answers to questions he/she never thought of asking. It already has had applications in medical research, commerce and national security, amongst others. This is a challenge for both law and ethics, especially in the context of issues of privacy. To what extent are the current laws adequate to deal with the new technology? Do we need a new set of laws or principles? Although this article does not give direct answer to those questions, it tries to highlight the various problem areas and to suggest possible approaches towards a solution.
Instruction level parallelism of non-uniform acyclic loops
Authors: Nelson L. Passos, Peng Xue, Hoang Bui
Venue: Journal of Computing Sciences in Colleges (2004)

New applications involving multi-rate systems, data compression and mathematical series, require high computational power, which most of the time implies the use of parallel processing. When the parallelism is associated with super-scalar architectures, code optimization must be applied at the instruction level in order to produce the desired performance. These improvements are usually applied to loop constructs due to their recurrence and criticality in the behavior of the application. Loop optimization has been studied for a very long time and, presently, it is still a complex subject to discuss in the classroom. In this study, the retiming theory is revisited and extended to the case of non-uniform one-dimensional acyclic loops with linear index expressions. The paper provides a new dimension in the study of this loop optimization technique.
Noninvasive determination of optical parameters in multilayered scattering media using finite difference time domain analysis
Authors: Tadatoshi Tanifuji, Daisuke Omori, Masanori Hijikata
Venue: Systems and Computers in Japan (2005)

This paper presents a solution method for the inverse problem in which an optical pulse is radiated to a biological medium and the optical parameters of the medium are estimated. The method in this paper is based on the FTDT method which the authors have previously formulated. It can be applied to estimation of the optical parameters in a biological object even if the optical parameters are nonhomogeneously distributed. First, the proposed method is applied to a homogeneous scattering medium and the validity of the method is verified. Then, the method is applied to a simplified human head model with a three-layered structure, composed of skull, gray matter, and white matter. The subset of optical parameters is defined on the basis of the independence of the differential amplitude, which represents the contribution of the optical parameters of the human head to the backscattered waveform, and the time waveform, which is obtained by differentiating the backscattered waveform with respect to each optical parameter. It is shown that the optical parameters of all three layers can be identified with an accuracy of &plusmn;1&percnt; by successively determining the optical parameters composing the subset. &copy; 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(7): 64&ndash;72, 2005; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.20134
Merger mania
Authors: Teri Robinson
Venue: netWorker (2005)

When my husband and I married, we sorted through CDs and albums lovingly collected since childhood and divested ourselves of any doubles. The end result? A vast music collection that exceeded our individual means without additional investment and which generated a bit of a windfall as we sold off the items that were redundant.Despite the potential gains, though, the merger didn't go off without a hitch. We grappled with the weighty issues---like whose copy of Dylan's Biograph or Modern English's After the Snow we would keep (extremely important if the union doesn't work out); whether CDs trumped vinyl; and whose maintenance standards should be adopted (I try to put CDs back in their jewel cases, my husband would use them for coasters if I let him).
ILIAD--language generation for instruction: Bolt, Beranek, and Newman
Authors: Madeleine Bates, Kirk Wilson
Venue: Issue 79 (January 1982) (1982)

The ILIAD system is an intelligent CAI system developed to give instruction and practice in English to children and adults who have language-delaying handicaps such as deafness or who are not native speakers of English. The student specifies grammatical or functional language topics and exercises are produced which contain sentences generated by the system. In order to provide highly personalized exercises and very specific tutorial guidance it is necessary for the system to have a deep understanding of the linguistic relationships in the sentences it generates.
An interface for &lsquo;flat music&rsquo;
Authors: Christopher Bailey
Venue: Organised Sound (2004)

Part of my listening experience has been a coming to terms with a certain set of musical forms that I call &lsquo;flat&rsquo;. Music in flat form means music that avoids obvious or dimensionally conjunct large-scale goals, points of arrival, &lsquo;climaxes&rsquo;, sectional boundaries, and the like, and therefore has proven difficult for many listeners. It has become clear to me that this music demands a different listening approach, one at odds with the way music is typically appreciated in the concert hall. This approach is one that composers of music in flat form can facilitate through today's computer-music resources. What I present here is a specific instance of such an approach: my composition Sand, a twenty-five-minute long work for computer-synthesised and processed sounds, was composed specifically to be experienced through a computer-music interface I built in the MAX&#x002F;MSP environment. This paper explores what I mean by &lsquo;flatness&rsquo;, how I came to terms with it as a listener, and how this coming-to-terms spawned the idea and construction of the interface. I then discuss the interface itself, the process of interaction with the listener, and technical aspects of the software.
Localization and routing in sensor networks by local angle information
Authors: Jehoshua Bruck, Jie Gao, Anxiao (Andrew) Jiang
Venue: Proceedings of the 6th ACM international symposium on Mobile ad hoc networking and computing (2005)

Location information is very useful in the design of sensor network infrastructures. In this paper, we study the anchor-free 2D localization problem by using local angle measurements in a sensor network. We prove that given a unit disk graph and the angles between adjacent edges, it is NP-hard to find a valid embedding in the plane such that neighboring nodes are within distance 1 from each other and non-neighboring nodes are at least distance 1 away. Despite the negative results, however, one can find a planar spanner of a unit disk graph by using only local angles. The planar spanner can be used to generate a set of virtual coordinates that enable efficient and local routing schemes such as geographical routing or approximate shortest path routing. We also proposed a practical anchor-free embedding scheme by solving a linear program. We show by simulation that not only does it give very good local embedding, i.e., neighboring nodes are close and non-neighboring nodes are far away, but it also gives a quite accurate global view such that geographical routing and approximate shortest path routing on the embedded graph are almost identical to those on the original (true) embedding. The embedding algorithm can be adapted to other models of wireless sensor networks and is robust to measurement noise.