ppxscal/embedding_network huggingface dataset:
Indexing the positions of continuously moving objects
Authors: Simonas Šaltenis, Christian S. Jensen, Scott T. Leutenegger, Mario A. Lopez
Venue: ACM SIGMOD Record (2000)

The coming years will witness dramatic advances in wireless communications as well as positioning technologies. As a result, tracking the changing positions of objects capable of continuous movement is becoming increasingly feasible and necessary. The present paper proposes a novel, R*-tree based indexing technique that supports the efficient querying of the current and projected future positions of such moving objects. The technique is capable of indexing objects moving in one-, two-, and three-dimensional space. Update algorithms enable the index to accommodate a dynamic data set, where objects may appear and disappear, and where changes occur in the anticipated positions of existing objects. A comprehensive performance study is reported.
Touch-sensing input devices
Authors: Ken Hinckley, Mike Sinclair
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

We can touch things, and our senses tell us when our hands are touching something. But most computer input devices cannot detect when the user touches or releases the device or some portion of the device. Thus, adding touch sensors to input devices offers many possibilities for novel interaction techniques. We demonstrate the TouchTrackball and the Scrolling TouchMouse, which use unobtrusive capacitance sensors to detect contact from the users hand without requiring pressure or mechanical actuation of a switch. We further demonstrate how the capabilities of these devices can be matched to an implicit interaction technique, the On-Demand Interface, which uses the passive information captured by touch sensors to fade in or fade out portions of a display depending on what the user is doing; a second technique uses explicit, intentional interaction with touch sensors for enhanced scrolling. We present our new devices in the context of a simple tax- onomy of tactile input technologies. Finally, we discuss the properties of touch-sensing as an input channel in general.
Light-weight context recovery for efficient and accurate program analyses
Authors: Donglin Liang, Mary Jean Harrold
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

To compute accurate information efficiently for programs that use pointer variables, a program analysis must account for the fact that a procedure may access different sets of memory locations when the procedure is invoked under different callsites. This paper presents light-weight context recovery, a technique that can efficiently determine whether a memory location is accessed by a procedure under a specific callsite. The paper also presents a technique that uses this information to improve the precision and efficiency of program analyses. Our empirical studies show that (1) light-weight context recovery can be quite precise in identifying the memory locations accessed by a procedure under a specific call-site and (2) distinguishing memory locations accessed by a procedure under different callsites can significantly improve the precision and the efficiency of program analyses on programs that use pointer variables.
First-class user-level threads
Authors: Brian D. Marsh, Michael L. Scott, Thomas J. LeBlanc, Evangelos P. Markatos
Venue: ACM SIGOPS Operating Systems Review (1991)

It is often desirable, for reasons of clarity, portability, and efficiency, to write parallel programs in which the number of processes is independent of the number of available processors. Several modern operating systems support more than one process in an address space, but the overhead of creating and synchronizing kernel processes can be high. Many runtime environments implement lightweight processes (threads) in user space, but this approach usually results in second-class status for threads, making it difficult or impossible to perform scheduling operations at appropriate times (e.g. when the current thread blocks in the kernel). In addition, a lack of common assumptions may also make it difficult for parallel programs or library routines that use dissimilar thread packages to communicate with each other, or to synchronize access to shared data.We describe a set of kernel mechanisms and conventions designed to accord first-class status to user-level threads, allowing them to be used in any reasonable way that traditional kernel-provided processes can be used, while leaving the details of their implementation to user-level code. The key features of our approach are (1) shared memory for asynchronous communication between the kernel and the user, (2) software interrupts for events that might require action on the part of a user-level scheduler, and (3) a scheduler interface convention that facilitates interactions in user space between dissimilar kinds of threads. We have incorporated these mechanisms in the Psyche parallel operating system, and have used them to implement several different kinds of user-level threads. We argue for our approach in terms of both flexibility and performance.
Uniqueness of Lower Semicontinuous Viscosity Solutions for the Minimum Time Problem
Authors: Olivier Alvarez, Shigeaki Koike, Isao Nakayama
Venue: SIAM Journal on Control and Optimization (2000)

We obtain the uniqueness of lower semicontinuous (LSC) viscosity solutions of the transformed minimum time problem assuming that they converge to zero on a "reachable" part of the target in appropriate directions. We present a counter-example which shows that the uniqueness does not hold without this convergence assumption.It was shown by Soravia that the uniqueness of LSC viscosity solutions having a "subsolution property" on the target holds. In order to verify this subsolution property, we show that the dynamic programming principle (DPP) holds inside for any LSC viscosity solutions.In order to obtain the DPP, we prepare appropriate approximate PDEs derived through Barles' inf-convolution and its variant.
It's engineering Jim &hellip; but not as we know it: software engineering &mdash; solution to the software crisis, or part of the problem?
Authors: Antony Bryant
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

This paper considers the impact and role of the 'engineering' metaphor, and argues that it is time to reconsider its impact on software development practice.
Image Field Categorization and Edge/Corner Detection from Gradient Covariance
Authors: Shigeru Ando
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

Edges, corners, and vertices in an image correspond to 1D (one-dimensional) and 2D discontinuities in the intensity surface of the underlying scene. Ridges and peaks correspond to 1D and 2D extrema in it. All of them can be characterized by the distribution of gradients, particularly by dimensionality of it. The approach to image field categorization here is to construct a covariance matrix of the gradient vector in each small window and apply the canonical correlation analysis to it. Schwarz's inequality on the matrix determinant and the related differential equation is the key to this analysis. We obtain two operators $P_{EG}$ and $Q_{EG}$ to categorize the image field into a unidirectionally varying region (UNIVAR), an omnidirectionally varying region (OMNIVAR), and a nonvarying region. We investigate the conditions under which their absolute maximum response, i.e., $P_{EG}=1$ and $Q_{EG}=1$, occurs in the small window and show that they are, respectively, the desired 1D and 2D discontinuities/extrema and OMNIVAR, is in many cases, a 1D pattern in polar coordinates. This leads to an algorithm to obtain further classification and accurate localization of them into edges, ridges, peaks, corners, and vertices through detailed analysis in the informative (varying) axis of them. We examined and compared the performance of the operators and the localization algorithm on various types of images and various noise levels. The results indicate that the proposed method is superior with respect to stability, localization, and resolution.
Application architecture (panel session): 2Tier or 3Tier? What is DBMS's role?
Authors: Anil K. Nori
Venue: ACM SIGMOD Record (2000)

Experienced panelist will share their views on application architecture, specially, as it relates to database systems. The discussion will focus on what technologies and mechanisms are necessary for developing web applications, and where these mechanisms should reside.
A Comprehensive Evaluation of Capture-Recapture Models for Estimating Software Defect Content
Authors: Lionel C. Briand, Khaled El Emam, Bernd G. Freimut, Oliver Laitenberger
Venue: IEEE Transactions on Software Engineering (2000)

An important requirement to control the inspection of software artifacts is to be able to decide, based on more objective information, whether the inspection can stop or whether it should continue to achieve a suitable level of artifact quality. A prediction of the number of remaining defects in an inspected artifact can be used for decision making. Several studies in software engineering have considered capture-recapture models, originally proposed by biologists to estimate animal populations, to make a prediction. However, few studies compare the actual number of remaining defects to the one predicted by a capture-recapture model on real software engineering artifacts. Thus, there is little work looking at the robustness of capture-recapture models under realistic software engineering conditions, where it is expected that some of their assumptions will be violated. Simulations have been performed, but no definite conclusions can be drawn regarding the degree of accuracy of such models under realistic inspection conditions and the factors affecting this accuracy. Furthermore, the existing studies focused on a subset of the existing capture-recapture models. Thus, a more exhaustive comparison is still missing. In this study, we focus on traditional inspections and estimate, based on actual inspections data, the degree of accuracy of relevant, state-of-the-art capture-recapture models as they have been proposed in biology and for which statistical estimators exist. In order to assess their robustness, we look at the impact of the number of inspectors and the number of actual defects on the estimators' accuracy based on actual inspection data. Our results show that models are strongly affected by the number of inspectors and, therefore, one must consider this factor before using capture-recapture models. When the number of inspectors is too small, no model is sufficiently accurate and underestimation may be substantial. In addition, some models perform better than others in a large number of conditions and plausible reasons are discussed. Based on our analyses, we recommend using a model taking into account that defects have different probabilities of being detected and the corresponding Jackknife Estimator. Furthermore, we attempt to calibrate the prediction models based on their relative error, as previously computed on other inspections. Although intuitive and straightforward, we identified theoretical limitations to this approach which were then confirmed by the data.
Design guidelines for landmarks to support navigation in virtual environments
Authors: Norman G. Vinson
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Unfamiliar, large-scale virtual environments are difficult to navigate. This paper presents design guidelines to ease navigation in such virtual environments. The guidelines presented here focus on the design and placement of landmarks in virtual environments. Moreover, the guidelines are based primarily on the extensive empirical literature on navigation in the real world. A rationale for this approach is provided by the similarities between navigational behavior in real and virtual environments.
The Aqua approximate query answering system
Authors: Swarup Acharya, Phillip B. Gibbons, Viswanath Poosala, Sridhar Ramaswamy
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

Aqua is a system for providing fast, approximate answers to aggregate queries, which are very common in OLAP applications. It has been designed to run on top of any commercial relational DBMS. Aqua precomputes synopses (special statistical summaries) of the original data and stores them in the DBMS. It provides approximate answers along with quality guarantees by rewriting the queries to run on these synopses. Finally, Aqua keeps the synopses up-to-date as the database changes, using fast incremental maintenance techniques.
Web-based student feedback to improve learning
Authors: Jason Lowder, Dianne Hagan
Venue: Proceedings of the 4th annual SIGCSE/SIGCUE ITiCSE conference on Innovation and technology in computer science education (1999)

A Web-based anonymous feedback facility has been used for three years to give students a voice and some ownership of the subjects they are studying, and to allow staff to make adjustments to the teaching program in time to help the current student group. Improvements have been made to the system, e.g. the ability for students to identify themselves, extensions to staff e-mail copies, discussion threads to delineate topic areas, and automatic generation of statistics on usage. These statistics show how the need for anonymity decreases as the level of maturity of the students increases. Other planned or recently added improvements are described..
Morphological Reversible Contour Representation
Authors: Yassin M.Y. Hasan, Lina J. Karam
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

In this paper, a novel morphological reversible contour representation of discrete binary images is proposed. A binary image is represented by a set of nonoverlapping multilevel contours and a residual image. In this proposed representation, the total number of pixels representing an image is far less than the total number of pixels obtained by the seed-based morphological contour-skeleton lossless representation. The proposed contour representation is simple, unique, and general without restrictions on the binary image to be represented. Moreover, it requires fewer number of operations to compute the proposed representation compared with other lossless morphological representation methods. The resulting multicontour image component is also robust to noise. An efficient differential chain contour coding scheme is employed to further compress the represented image. The proposed method yields very low bit rates compared to the existing morphological techniques. To exactly reconstruct an original image, an automatic filling procedure, which properly fills a proper multicontour image according to its topological structure without need of seed points, is proposed. The morphological unique contour representation and its lossless reconstruction techniques have been tested on images with varying size and complexity. Examples are presented to illustrate the performance of the proposed method.
Dynamic R D Investment Policies
Authors: Paul D. Childs, Alexander J. Triantis
Venue: Management Science (1999)

This paper examines dynamic R&D investment policies and the valuation of R&D programs in a contingent claims framework. We incorporate the following characteristics of R&D programs into our model: learning-by-doing, collateral learning between different projects in the program, interaction between project cash flows, periodic reevaluations of the program, different intensities of investment, capital rationing constraints, and competition. We show that a firm may invest in multiple projects even if only one can be implemented after development is complete. Furthermore, the firm may significantly alter its funding policy over time. For example, it may simultaneously develop multiple projects for a period of time, then focus on a lead project, and potentially resume funding of a "backup" project if the lead project fails to deliver on its early promise. We show how a firm can forecast expected R&D spending through time for an optimally executed R&D program. While project volatility plays an important role in determining R&D program value, we find that for high volatility projects the optimal investment policy is not very sensitive to changes in (or misestimation of) volatility. In considering whether to accelerate development of a project, a firm should balance the adverse effects of increased costs and the loss of investment flexibility against the positive effects of rapid uncertainty resolution and accelerated cash flows. In the presence of a budget constraint that prevents the firm from simultaneously accelerating projects and developing projects in parallel, we find that, if one project significantly dominates another early in the development stage, the option to accelerate the lead project is likely to be more valuable than the option to exchange projects. Thus, the backup project would be shelved in order to commit extra resources to development of the lead project. Finally, competition from other firms leads to more parallel investment in the early development stages of projects, less parallel investment in the latter stages of development, and lower overall investment.
Converting an Ada 83 application to Ada 95
Authors: Oliver Cole
Venue: ACM SIGAda Ada Letters (1999)

This paper can also be found at the OC Systems web site.
Visualizing implicit queries for information management and retrieval
Authors: Mary Czerwinski, Susan Dumais, George Robertson, Susan Dziadosz, Scott Tiernan, Maarten van Dantzich
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

In this paper, we describe the use of similarity metrics in a novel visual environment for storing and retrieving favorite web pages. The similarity metrics, called Implicit Queries, are used to automatically highlight stored web pages that are related to the currently selected web page. Two experiments explored how users manage their personal web information space with and without the Implicit Query highlighting and later retrieve their stored web pages. When storing and organizing web pages, users with Implicit Query highlighting generated slightly more categories. Implicit Queries also led to faster web page retrieval time, although the results were not statistically significant.
Smart packets: applying active networks to network management
Authors: Beverly Schwartz, Alden W. Jackson, W. Timothy Strayer, Wenyi Zhou, R. Dennis Rockwell, Craig Partridge
Venue: ACM Transactions on Computer Systems (TOCS) (2000)

This article introduces Smart Packets and describes the smart Packets architecture, the packet formats, the language and its design goals, and security considerations. Smart Packets is an Active Networks project focusing on applying active networks technology to network management and monitoring. Messages in active networks are programs that are executed at nodes on the path to one or more target hosts. Smart Packets programs are written in a tightly encoded, safe language specifically designed to support network management and avoid dangerous constructs and accesses. Smart Packets improves the management of large complex networks by (1) moving management decision points closer to the node being managed, (2) targeting specific aspects of the node for information rather than exhaustive collection via polling, and (3) abstracting the management concepts to language constructs, allowing nimble network control.
Using Department of Veterans Affairs Administrative Databases To Examine Long Term Care Utilization for Men and Women Veterans
Authors: Marylou Guihan, Frances M. Weaver, Diane C. Cowper, Tammy Nydam, Scott Miskevics
Venue: Journal of Medical Systems (1999)

We examined long term care (LTC) utilization by male and female veterans using administrative databases maintained by VA. Research questions included: (1) Which LTC services are utilized? (2) Do utilization patterns of older veterans differ from those of elderly persons in the general U.S. population? (3) Do LTC needs of veterans vary by gender? We were unable to track LTC utilization of individuals across administrative databases. Some databases could only provide information at the national level, or alternatively, were available only at local facilities, or only at the patient or program-level data&mdash;making it impossible to get a clear picture of all the services received by an individual. Those planning to use administrative databases to conduct research must: (1) take more time than expected&semi; (2) be flexible/willing to compromise, (3) &ldquo;ferret out&rdquo; information, and (4) recognize that because of dynamism inherent in information systems, results may change over time.
Systematic cycle budget versus system power trade-off: a new perspective on system exploration of real-time data-dominated applications
Authors: Erik Brockmeyer, Arnout Vandecappelle, Francky Catthoor
Venue: Proceedings of the 2000 international symposium on Low power electronics and design (2000)

In contrast to current design practice for (programmable) processor mapping, which mainly targets performance, we focus on a systematic trade-off between cycle budget and energy consumed in the background memory organization. The latter is a crucial component in many of todays designs, including multi-media, network protocols and telecom signal processing. We have a systematic way and tool to explore both freedoms and to arrive at Pareto charts, in which for a given application the lowest cost implementation of the memory organization is plotted against the available cycle budget per submodule. This by making optimal usage of a parallelized memory architecture. We indicate, with results on a digital audio broadcasting receiver and an image compression demonstrator, how to effectively use the Pareto plot to gain significantly in overall system energy consumption within the global real-time constraints.
Multiple downcasting techniques
Authors: Puppydog P. O. P., L. B. S. Raccoon
Venue: ACM SIGSOFT Software Engineering Notes (1999)

In this paper, we describe and compare techniques that implement multiple downcasting in strongly-typed languages. We conclude that multimethods stand out as the single best technique. In the first section, we describe seven commonly used techniques. In the second section, we compare these seven techniques using ten criteria. And, in the third section, we comment on some additional techniques.Multiple downcasting occurs so often that developers use a variety of terms to describe it, and a variety of language constructs and patterns to implement it. "Feed the animals," "driver-vehicle," and "parallel hierarchies" are well-known examples that require multiple downcasting. "Multiple type dispatch" and "covariant subclassing" identify different facets of multiple downcasting. "Dynamic type casting," "typecase statements," and the "visitor pattern" are frequently used to implement multiple downcasting. We believe that multiple downcasting is not a mistake or the result of poor program design, rather multiple downcasting is a specific technique that implements a specific kind of application semantics.In the animal hierarchy shown in Figure 1, cows eat grass, wolves eat meat, and in the superclass, animals eat food. The generalization that animals eat food is imprecise: it ignores the facts that cows only eat grass and wolves only eat meat. So, how should developers write a function to safely "feed the animals" without getting the types mixed up? In Program 1, we show how a developer might like to "feed the animals" in C++. The feed_unsafely function may fail, while the feed_safely function works properly for all combinations of foods and animals. The animal hierarchy will not compile in C++, because the eat method is covariant.In this paper, we elaborate ideas and examples from A Middle-Out Concept of Hierarchy. We adapted the "feed the animals" example from Are Cows Animals? by Shang.