ppxscal/embedding_network huggingface dataset:
Accurate and Reliable Algorithms for Global Illumination
Authors: Daniel Lischinski
Venue:  (1994)

The simulation of global illumination is one of the most fundamental problems in computer graphics, with applications in a wide variety of areas, such as architecture and lighting design, computer-aided design, and virtual reality. This problem concerns the transport of light energy between reflective surfaces in an environment. During the past decade, radiosity has become the method of choice for simulating global illumination in diffuse environments. Despite much recent progress in efficiency and applicability of radiosity methods, there are several very important open issues remaining: 1) Radiosity images suffer from many visual artifacts, resulting from lack of reliable automatic discretization algorithms; and 2) Current radiosity algorithms do not provide the user with guaranteed bounds or reliable estimates of the approximation errors. As a result, current radiosity systems require very careful and time-consuming user intervention in the discretization process, and the accuracy of the resulting solutions can only be assessed by visual appearance. This thesis presents new radiosity algorithms for diffuse polyhedral environments that address the open problems mentioned above. First, we have improved and combined together two recently developed radiosity approaches: hierarchical radiosity and discontinuity meshing. An improved hierarchical radiosity algorithm that is based on a discontinuity-driven subdivision strategy to achieve better numerical accuracy and faster convergence is used to compute the global distribution of light energy in an environment. Then, a new algorithm based on discontinuity meshing uses the hierarchical solution to reconstruct a visually accurate approximation to the radiance function. Thus, results of high visual quality can be obtained even from coarse global illumination simulations. The solution is performed entirely in object-space, which enables users to "walk" through high-fidelity shaded virtual environments in real time, using appropriate display hardware. Second, we have developed algorithms that compute a posteriori error bounds and estimates for local and total errors in hierarchical radiosity solutions. A conservative algorithm computes guaranteed upper bounds on the errors. A non-conservative algorithm is capable of computing more realistic error estimates more efficiently. These error estimates are used in a new error-driven refinement strategy for hierarchical radiosity, resulting in faster convergence.
Concepts and Structures in Programming Languages
Authors: Peter Wegner
Venue:  (1968)

These notes develop a set of concepts for describing program structures which arise in programming languages. These concepts are then used to discuss FORTRAN, ALGOL, macro languages, languages with definitional facilities, SNOBOL4, and LISP from a unifying point of view. The central concept is that of an information structure model. Emphasis is placed on the sequence of information structures generated by programs of a programming language during their execution. Section 1 considers program representation, interpretation, and compilation. Section 2 introduces the concept of an information structure model for characterizing classes of computations. Sections 3 and 4 show that computers and programming languages are examples of information structure models. Sections 5 and 6 respectively consider the information structures associated with FORTRAN and ALGOL programs during their execution. Section 7 shows how syntax and semantics may be specified for information structure models and introduces the notion of an interpreter-interpreter. Section 8 develops information structure models for macro languages. Section 9 introduces the concept of binding time and discusses declarations and definitional facilities in programming languages. Sections 10 and 11 consider information structure models for SNOBOL4 and LISP. Computer science may be defined as the study of representation and transformation of information structures. The present approach is concerned with the representation of programs as information structures and with the transformations of these structures during execution, and directly reflects the above definition of computer science. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Reactive Programming in Standard ML
Authors: Riccardo R. Pucella
Venue: Proceedings of the 1998 International Conference on Computer Languages (1998)

Reactive systems are systems that maintain an ongoing interaction with their environment, activated by receiving input events from the environment and producing output events in response. Modern programming languages designed to program such systems use a paradigm based on the notions of instants and activations. We describe a library for Standard ML that provides basic primitives for programming reactive systems. The library is a low-level system upon which more sophisticated reactive behaviors can be built, which provides a convenient framework for prototyping extensions to existing reactive languages.
Equation of State of Two-Dimensional Lattice Chains at the Theta Point
Authors: Ronald Dickman
Venue:  (1991)

Systems of two-dimensional lattice self-avoiding walks with nearest-neighbor attracitve interactions are studied in Monte Carlo simulations, focusing on the point, where the second virial coefficient vanishes. The equation of state is determined for the first time, for chains of 40 and 80 segments over a wide range of densities. The results are consistent with des Cloizeaux'' scaling law, and yield a value for the tricritical exponent vt=0.57(3), in close agreement with recent estimates. The density profile at a wall, and the variation of chain dimensions with bulk density are also studied. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
The Effect of Context on Training: Is Learning Situated?
Authors: Lynne Reder, Roberta L. Klatzky
Venue:  (1994)

This paper addresses issues associated with transfer of training; in particular, the importance of mimicking the contexts of application during training: When will a skill transfer from one situation of application to another, and what aspects of training affect a learner''s ability to transfer the learning to new situations? Although there exist many examples of failure to show good transfer of training, the failures are more surprising and tend to mask the successes. With appropriate training there is generalization to a variety of contexts. Such training should include variable contexts during instruction, concrete examples, and abstract rules and procedures. Claims made by proponents of Situated Learning Theory suggest that training must be done in the context of the situation of application. We agree that learning is unlikely to transfer if taught in only one context with no examples from other contexts; however, because it is difficult to anticipate all future contexts of application, trainers are advised not to so constrain instruction. Although training and transfer should have identical elements, there is evidence that part-whole training is often the appropriate method of instruction. This argues against apprenticeship learning during early stages of acquisition for many skills. Further, too much fidelity in simulation may lack cost effectiveness and may even be detrimental to the early acquisition process.
Closed-form Analytic Maps in One and Two DimensionsCan Simulate Turing Machines
Authors: Pascal Koiran, Cristopher Moore
Venue:  (1996)

We show closed-form analytic functions consisting of a finite number of trigonometric terms can simulate Turing machines, with exponential slowdown in one dimension or in real time in two or more.
Rethinking Rights and Regulations: Institutional Responses to New Communications Technologies
Authors: Lorrie Faith Cranor
Venue:  (2003)

:The contributors to this volume examine issues raised by the intersection of new communications technologies and public policy in this post-boom, post-bust era. Originally presented at the 30th Research Conference on Communication, Information, and Internet Policy (TPRC 2002)--traditionally a showcase for the best academic research on this topic--their work combines hard data and deep analysis to explore the dynamic interplay between technological development and society.The chapters in the first section consider the ways society conceptualizes new information technologies and their implications for law and policy, examining the common metaphor of "cyberspace as place," alternative definitions of the Internet, the concept of a namespace, and measures of diffusion. The chapters in the second section discuss how technological change may force the rethinking of legal rights; topics considered include spectrum rights, intellectual property, copyright and "paracopyright," and the abridgement of constitutional rights by commercial rights in ISP rules. Chapters in the third and final section examine the constant adjustment and reinterpretation of regulations in response to technological change, considering, among other subjects, liability regimes for common carriers and the 1996 detariffing rule, privacy and enhanced 911, and the residual effect of state ownership on privatized telecommunication carriers. The policy implications of Rethinking Rights and Regulations are clear: major institutional changes may be the necessary response to major advances in telecommunications technology.
A new development environment for an event-based distributed system
Authors: Tsun-Yu Hsiao, Nei-Chiung Perng, Winston Lo, Yue-Shan Chang, Shyan-Ming Yuan
Venue: Computer Standards Interfaces (2003)

The rapid growth of data exchange on the Internet has created many critical problems that require an answer. Traditional data exchange systems based on client/server communication models are less scalable and incur especially high maintenance cost in the data exchange domain. For these reasons, many researchers have switched their interest to asynchronous communication models. Although Message-Oriented Middleware (MOM) is a middle-tier infrastructure that links operating systems and applications, such asynchronous communication APIs supported by middleware vendors are usually hard to use. For these reasons, in this study, we present a new development environment for asynchronous communication platforms which we term Ghostwriter. The keyword for our development environment is 'easy', that is, easy to use, easy to develop, and easy to deploy. Therefore, many researchers have switched their interest to asynchronous communication models, In addition, learning about and implementing the functions of the asynchronous communication's clients in Ghostwriter environment is simple. Other benefits are a lower technical learning curve, help for concentrate on system design, has easily reusable components, and easily integrated applications.
Incorporating Software Reliability Engineering into the Test Process for an Extensive GUI-Based Network Management System
Authors: Deirdre Donovan, Chryssa Dislis, Ray Murphy, Stephen Unger, Christina Kenneally, Janet Young, Liz Sheehan
Venue: Proceedings of the 12th International Symposium on Software Reliability Engineering (2001)

This paper describes he process used to adapt Software Reliability Engineering (SRE) to a GUI-based ne work management system. This system is used for the operations and maintenance of GSM mobile elephone networks.The objectives were to formally quantifycustomer usage of the software in he field, to increase test effectiveness, and to establish an accurate pre-release software quality indicator. It reports on a novel use of capture and playback tools to automatically generate operational profiles on a GUI system, and on the process model developed to adapt and implement SRE. I also describes the application, with minimal overhead, of the operational profiles to the existing test process and practical lessons learned as a result of this experience. Initial results show that it is no necessary to wait until theend of the SRE implementation process to see benefits. This paper demonstrates that significant test effectiveness improvements can be seen during the implementation ofSRE.
QoS Oriented Bandwidth Management Scheme for Stable Multimedia Services on the IMT-2000 Networks
Authors: Sung-Hyun Cho, Seung-Jei Yang, Shin Heu, Sung-Han Park
Venue: Proceedings of the The International Conference on Information Technology: Coding and Computing (ITCC'00) (2000)

In this paper, we propose a bandwidth management scheme to efficiently guarantee the QoS of various services on IMT-2000 networks. The proposed bandwidth management scheme consists of the call admission control based on the guard channel and the time slot scheduling in wireless links. For the call admission, control the preemption and deprivation method are used to overcome the problems in the previous guard channel scheme. The proposed time slot-scheduling scheme allocates time slots based on the QoS requirements of each user. The time slots are dynamically scheduled by considering the current traffic conditions with DQRUMA protocol. The simulation results show that the proposed bandwidth scheme has better performance than the previous works in terms of the handoff failure probability and the packet delay time.
Frequency-Based Error Back-Propagation in a Cortical Network
Authors: Rafal Bogacz, Malcolm W. Brown, Christophe Giraud-Carrier
Venue: Proceedings of the IEEE-INNS-ENNS International Joint Conference on Neural Networks (IJCNN'00)-Volume 2 - Volume 2 (2000)

This paper presents a biologically plausible mechanism of back-propagating network output error to previous layers of processing in a particular multi-layer neural network. This mechanism is used in a network that is designed to mimic familiarity discrimination as performed by the perirhinal cortex of the temporal lobe. In the algorithm, the error of the network during an initial classification period regulates the frequency of neuronal activity in a succeeding memorizing period via an inhibitory circuit, such that the frequency in this memorizing period is proportional to the error. Synaptic weight modifications are made according to activity-dependent Hebbian rules, such as may be used in the brain. The magnitude of the modification depends on the frequency of the activity. Hence, the magnitude of weight modification is proportional to the network error.
The Scalability of an Object Descriptor Architecture OODBMS
Authors: Kwok K. Yu, Byung S. Lee, Michael R. Olson
Venue: Proceedings of the 1999 International Symposium on Database Engineering & Applications (1999)

An object database management system (OODBMS) has been often criticized for its alleged insufficient scalability for a large-scale production system. We investigated the scalability issue on a commercial OODBMS with a focus on the scalability with respect to the number of objects. Our approach was a benchmark experiment using the loading and indexing of SGML text documents as an application. The application was characterized by its small granularity of objects, which resulted in a huge number of objects in order to make a large database volume. The OODBMS we used was built in a so-called "object descriptor architecture (ODA)" as opposed to a "virtual memory mapping architecture (VMMA)". The results showed that the OODBMS scaled better than we had anticipated. It required, however, algorithmic resolutions to overcome the shortage of object cache space. Three key resolutions were made. First, we created indexes in fragments by committing a loading transaction before the object cache space became full, and subsequently merged the fragments into one master index. Secondly, we had the application release cached object descriptors (CODs) as soon as they became unnecessary. Thirdly, we utilized a query cursor mechanism to fetch the objects returned from a query piece by piece without overflowing the object cache space. Currently we are attempting to push the scalability up to filling up the maximum available hard disk space.
An exploratory Study of IR Interaction for User Interface Design
Authors: Preben Hansen
Venue:  (2001)

Information seeking is an dynamic and interactive process. Factors like users'' information needs, individual differences, goals and tasks, knowledge and cognitive abilities etc. influence the information seeking process, and need to be identified and supported in the user interface design. We adopt a user-centered approach to establish a link between research within the IR interaction perspective and the methods in HCI on how to evaluate information seeking interaction in a hypertext IR system (Dienst). Our purpose with this exploratory study is to identify, describe and acquire knowledge of characteristics of the user population, and finally, to make suggestions for supporting users in user interface design. For the evaluation task, we have applied HCI evaluation techniques to our IR evaluation to make a connection between the traditional IR evaluation and HCI evaluation, combining different qualitative and quantitative data collection and analyzing methods, implemented in an experimental real-world online WWW setting. This methodology combined online (WWW-based) questionnaires and database log statistics. Preliminary results revealed several "hidden" realities: a mismatch between what people said they wanted to do as opposed to what they actually did. We also observed that people initially expected a specific function, but when using the system, they did not use it. Finally, we established some group differences concerning variables like previous experience searching information in hypertext systems, IR knowledge and browsing/searching strategies. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Machine learning in automated text categorisation
Authors: Fabrizio Sebastiani
Venue:  (1999)

The automated categorisation (or classification) of texts into topical categories has a long history, dating back at least to the early ''60s. Until the late ''80s, the most effective approach to the problem seemed to be that of manually building automatic classifiers by means of {\em knowledge-engineering} techniques, i.e.\ manually defining a set of rules encoding expert knowledge on how to classify documents under a given set of categories. In the ''90s, with the booming production and availability of on-line documents, automated text categorisation has witnessed an increased and renewed interest, prompted by which the {\em machine learning} paradigm to automatic classifier construction has emerged and definitely superseded the knowledge-engineering approach. Within the machine learning paradigm, a general inductive process (called the {\em learner}) automatically builds a classifier (also called the {\em rule}, or the {\em hypothesis}) by ``learning'''', from a set of previously classified documents, the characteristics of one or more categories. The advantages of this approach are a very good effectiveness, a considerable savings in terms of expert manpower, and domain independence. In this survey we look at the main approaches that have been taken towards automatic text categorisation within the general machine learning paradigm. Issues pertaining to document indexing, classifier construction, and classifier evaluation, will be discussed in detail. A final section will be devoted to the techniques that have specifically been devised for an emerging application such as the automatic classification of Web pages into ``{\sc Yahoo!}-like'''' hierarchically structured sets of categories.
A Suite of Database Replication Protocols based on Group Communication Primitives
Authors: Bettina Kemme, Gustavo Alonso
Venue: Proceedings of the The 18th International Conference on Distributed Computing Systems (1998)

This paper proposes a family of replication protocols based on group communication in order to address some of the concerns expressed by database designers regarding existing replication solutions. Due to these concerns, current database systems allow inconsistencies and often resort to centralized approaches, thereby reducing some of the key advantages provided by replication.The protocols presented in this paper take advantage of the semantics of group communication and use relaxed isolation guarantees to eliminate the possibility of deadlocks, reduce the message overhead, and increase performance. A simulation study shows the feasibility of the approach and the flexibility with which different types of bottlenecks can be circumvented.
On a model for phase separation in binary alloys driven by mechanical effects
Authors: Elena Bonetti, Pierluigi Colli, Wolfang Dreyer, Gianni Gilardi, Giulio Schimperna, Sprekels Sprekels
Venue:  (2001)

This work is concerned with the mathematical analysis of a system of partial differential equations modeling the effect of phase separation driven by mechanical actions in binary alloys like tin/lead solders. The system combines the (quasistationary) balance of linear momentum with a fourth order evolution equation of Cahn\_Hilliard type for the phase separation, and it is highly nonlinearly coupled. Existence and uniqueness results are shown. TEL:: 0382505631 EMAIL:: bonetti@dimat.unipv.it
On Macula's error-correcting pool designs
Authors: F. K. Hwang
Venue: Discrete Mathematics (2003)

We show that Macula's claim of a Hamming distance 4 between any two candidate sets of positive clones in his pool design is incorrect. However, a previous proof of his on a weaker result (with a condition on design parameters) is correct. We also show that the condition is sharp and the distance 4 result is also sharp for arbitrary parameter values.
Distributed Motion Coordination with Co-Fields: A Case Study in Urban Traffic Management
Authors: Marco Mamei, Franco Zambonelli, Letizia Leonardi
Venue: Proceedings of the The Sixth International Symposium on Autonomous Decentralized Systems (ISADS'03) (2003)

Coordinating the activities of distributed autonomous entities challenges traditional approaches to distributed coordination and calls for new paradigms and supporting middleware. This paper focuses on the problem of orchestrating the movements' of mobile autonomous agents in a large-scale distributed systems, and proposes an approach that takes inspiration from physics. Our idea is to have the movements of agents driven by force fields, generated by the agentsthemselves and propagated via some infrastructure. A globally coordinated and self-organized behavior in the agent's movements can then emerge due to the interrelated effects of agents following the shape of the fields and dynamic fields re-shaping. The approach is presented and its effectiveness described with regard to a concreted case study in the area of urban traffic coordination.
Syntax and semantics of a high-level intermediate representation for ASF+SDF
Authors: Jan A. Bergstra, Mark Brand
Venue:  (2000)

Developing a compiler for \asdf\ has been a challenging task. The compilation of \asdf\ is performed using an intermediate language \muasf, an abstract syntax representation of \asdf. Although \asdf\ is quite simple to use, it provides a number of features which have an unclear semantics. By means of a number of examples in \muasf\ and a more mathematical notation a number of these semantic issues are clarified. These examples are helpful for both the compiler designer and the specification writer.