ppxscal/embedding_network huggingface dataset:
Performing replacement in modem pools
Authors: Yannis Smaragdakis, Paul Wilson
Venue: Proceedings of the annual conference on USENIX Annual Technical Conference (2000)

We examine a policy for managing modem pools that disconnects users only if not enough modems are available for other users to connect. Managing the modem pool then becomes a replacement problem, similar to buffer cache management (e.g., in virtual memory systems). When a new connection request is received, the system needs to find a user to "replace". In this paper we examine such demand-disconnect schemes using extensive activity data from actual ISPs. We discuss various replacement policies and propose CIRG: a novel replacement algorithm that is well suited for modem pools. In general, the choice of algorithm is significant. A naive algorithm (e.g., one that randomly replaces any user who has been inactive for a while) incurs many tens of percent more "faults" (i.e., disconnections of users who are likely to want to be active again soon) than the LRU algorithm, which, in turn, incurs 10% more faults than CIRG. For good replacement algorithms, the impact can be significant in terms of resource requirements. We show that the same standards of service as a system that does not disconnect idle users can be achieved with up to 13% fewer modems.
Experience and results from the implementation of an ATM socket family
Authors: Richard Black, Simon Crosby
Venue: Proceedings of the USENIX Winter 1994 Technical Conference on USENIX Winter 1994 Technical Conference (1994)

This paper describes the implementation of an ATM protocol stack as a protocol family within a 4.3 BSD derived Unix. A novel approach to the implementation of the management and control functions for the ATM protocol stack has been adopted. The data path is implemented within the kernel but all control and management functions are implemented by a user space daemon. An encapsulation of IP on the ATM protocol is provided by means of a logical IP interface. The mapping of IP addresses to ATM addresses is performed by the user space daemon.
High level hardware validation using hierarchical message sequence charts
Authors: P. K. Murthy, S. R. Rajan, K. Takayama
Venue: Proceedings of the High-Level Design Validation and Test Workshop, 2004. Ninth IEEE International (2004)

We describe a methodology for designing, testing, and verifying hardware designs from a high level of abstraction, using a visual formalism based on hierarchical message sequence charts. We develop a method for generating behaviors and monitors automatically from this high level description, and using it to validate actual hardware implementations developed by design teams. We apply our methodology to the design of a PCl-Express switch, and show that the methodology is useful in finding many design errors. We develop an enhanced hMSC language that can be much better suited for describing complex standards and protocols like the PCI-express.
OverCite: a distributed, cooperative citeseer
Authors: Jeremy Stribling, Jinyang Li, Isaac G. Councill, M. Frans Kaashoek, Robert Morris
Venue: Proceedings of the 3rd conference on Networked Systems Design & Implementation - Volume 3 (2006)

CiteSeer is a popular online resource for the computer science research community, allowing users to search and browse a large archive of research papers. CiteSeer is expensive: it generates 35 GB of network traffic per day, requires nearly one terabyte of disk storage, and needs significant human maintenance. OverCite is a new digital research library system that aggregates donated resources at multiple sites to provide CiteSeer-like document search and retrieval. OverCite enables members of the community to share the costs of running CiteSeer. The challenge facing OverCite is how to provide scalable and load-balanced storage and query processing with automatic data management. OverCite uses a three-tier design: presentation servers provide an identical user interface to CiteSeer's; application servers partition and replicate a search index to spread the work of answering each query among several nodes; and a distributed hash table stores documents and metadata, and coordinates the activities of the servers. Evaluation of a prototype shows that OverCite increases its query throughput by a factor of seven with a nine-fold increase in the number of servers. OverCite requires more total storage and network bandwidth than centralized CiteSeer, but spreads these costs over all the sites. OverCite can exploit the resources of these sites to support new features such as document alerts and to scale to larger data sets.
Silicon Evaluation of Static Alternative Fault Models
Authors: Chris Schuermyer, Jewel Pangilinan, Jay Jahangiri, Martin Keim, Janusz Rajski, Brady Benware
Venue: Proceedings of the 25th IEEE VLSI Test Symmposium (2007)

This paper presents an extensive study on evaluating the effects of static alternative fault models (AFM) on product quality in the face of the latest defect screening techniques. The fault models that are presented in this research are multiple-detect stuck-at, static transition fault, and layout-based deterministic bridges. The results show the quality impact when these new fault models are combined with a high quality stuck-at and TDF test sets.
Fast and exact direct illumination
Authors: F. Mora, L. Aveneau
Venue: Proceedings of the Computer Graphics International 2005 (2005)

Rendering high quality soft shadows from area light sources is necessary to increase the level of realism. Quality soft shadows are closely related to the visibility computation. An accurate visibility information improves the shadows realism. However, this remains a challenging problem since even small visibility approximations can lead to unacceptable errors in a picture. We propose a new approach to this problem, based on an exact visibility pre-computation, done in the Plucker space. It takes advantage of this first step to provide an exact from-point visibility query algorithm. We propose several results in a ray tracing application, where the direct illumination at any given point is provided with a fast computation, and with a high degree of quality.
A more efficient time Petri net state space abstraction preserving linear properties
Authors: Hanifa Boucheneb, Hind Rakkay
Venue: Proceedings of the Seventh International Conference on Application of Concurrency to System Design (2007)

We consider here Time Petri nets (TPN model). We first propose an abstraction to its generally infinite state space which preserves linear properties1 of the TPN model. Comparing with TPN abstractions proposed in the literature, our abstraction produces graphs which are both smaller and faster to compute. In addition, our characterization of abstracted states allows a significative gain in space. Afterwards, we show how to apply Yoneda's partial order reduction technique to construct directly reduced graphs useful to verify LTL-X properties of the model. Using our approach, both time and space complexities are significantly reduced.
Understanding threads in an advanced java course
Authors: Tamar Benaya, Ela Zur
Venue: ACM SIGCSE Bulletin (2007)

This poster describes difficultiesin understanding threads in an Advanced Java course given at the Computer Science department of the Open University of Israel (OUI). We present a typical question which focuseson several aspects of multi-threaded programming given in an exam. We discuss the students' answersand point to typical misunderstandings of the topic.
A Service-Oriented Extension of the V-Modell XT
Authors: Michael Meisinger, Ingolf H. Kruger
Venue: Proceedings of the 14th Annual IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (2007)

The ever growing size and complexity of both technical and business systems requires efficient software engineering approaches to keep development cost under control while still being able to finish development efforts in time with the required functionality and quality. Systematic software and systems engineering approaches help to push the boundary further and leverage the complexity on many different levels. On the one hand, the availability of appropriate models and notations for the systems under development throughout the development cycle and for all levels of abstraction helps to understand and modify manageable views of the system. On the other hand, systematic development processes can provide the harness for successful project execution and for the ability to repeatedly create results that meet the required quality standards and functionality within the budgeted cost and time. In this paper we combine a proven generic project management framework with a methodology for developing complex multi-functional systems. We embed our service-oriented development approach for reactive systems into the system development process model V-Modell XT by providing a modular extension of the V-Modell XT for service-oriented development. We introduce our development approach by means of a running example from the complex control systems domain, the BART traffic controller example.
Trust Enhanced Secure Mobile Ad-Hoc Network Routing
Authors: Venkat Balakrishnan, Vijay Varadharajan, Phillip Lucs, Udaya Kiran Tupakula
Venue: Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 02 (2007)

In recent years, several trust and reputation models have been proposed to enhance the security of mobile ad hoc networks. However, they either fail to capture evidence of trustworthiness within the limitations of the network, or introduce additional problems while capturing the evidence. In this paper, we propose a reputation-based trust model known as Secure MANET Routing with Trust Intrigue (SMRTI). In our model, the evidence of trustworthiness is captured in an efficient manner and from broader perspectives including direct interactions with neighbours, observing interactions of neighbours and through recommendations. SMRTI captures evidence from direct interactions with neighbours in order to identify their benign and malicious behaviours. It also captures evidence for misbehaviours by observing the interactions of neighbours. Lastly, the evidence captured from recommendations is used to summarize the benign behaviour of multi-hop nodes. Unlike other models, we adopt a novel approach to capture evidence from recommendations, which eliminates recommender's bias, free-riding, and honest-elicitation. SMRTI utilizes the captured evidence to predict whether a node is either benign or misbehaving. It then applies the prediction to enhance the security of communications depending on the decision policies, such as whether to send a packet to or forward a packet on behalf of other nodes. Finally, we demonstrate the performance of our model through simulation results.
Effect of Computer-Based Video Games on Children: An Experimental Study
Authors: Tsung-Yen Chuang, Wei-Fan
Venue: Proceedings of the The First IEEE International Workshop on Digital Game and Intelligent Toy Enhanced Learning (2007)

This experimental study investigated whether computer-based video games facilitate children's cognitive learning. In comparison to traditional computer-assisted instruction (CAI), this study explored the impact of the varied types of instructional delivery strategies on children's learning achievement. One major research null hypothesis was tested: no statistically significant differences in students' achievement when they receive two different instructional treatments: (1) traditional CAI; and (2) a computer-based video game. One hundred and eight third-graders from a middle/high socio-economic standard school district in Taiwan participated in the study. Results indicate that computer-based video game playing not only improves participants' fact/recall processes (F=5.288, p\le.05), but also promotes problem-solving skills by recognizing multiple solutions for problems (F=5.656, p\le.05).
Successes and Future of the Joint Weather Research and Forecasting Model Distributed Center Project
Authors: F. Anthony Eckel, Steven Rugg, Stephen Klotz
Venue: Proceedings of the HPCMP Users Group Conference (2006)

In 2003 AFWA and FNMOC were awarded identical IBM P-655 computer systems by HPCMP. These systems, which contain a total of 192 processors, 384 GB of memory and 6 TB of disk space, support the Joint Operational Testbed for the WRF Modeling Framework, hereafter referred to as the distributed center (DC) project. The project's objectives are to conduct operational tests of the National Center for Atmospheric Research (NCAR's) Weather Research and Forcasting (WRF) model, determine WRF configurations that best meet the unique mesoscale numerical weather prediction (NWP) requirements of the Department of Defense (DoD), develop and test mesoscale ensemble forecasting (EF) methods in an operational environment, and evaluate the applicability of grid computing to the stringent and unique requirements of NWP.
Minimum classification error training of hidden Markov models for handwriting recognition
Authors: A. E. Biem
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2001. on IEEE International Conference - Volume 03 (2001)

This paper evaluates the application of minimum classification error (MCE) training to online-handwritten text recognition based on hidden Markov models. We describe an allograph-based, character level MCE training aimed at minimizing the character error rate while enabling flexibility in writing style. Experiments on a writer-independent discrete character recognition task, covering all alpha-numerical characters and keyboard symbols, show that MCE achieves more than 30% character error rate reduction compared to the baseline maximum likelihood-based system.
Multiresolution MRF-based texture segmentation using the Wreath Product Transform phase
Authors: G. Mirchandani
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 200. on IEEE International Conference - Volume 02 (2001)

We bring local phase and multiresolution analysis to the texture segmentation problem. A Markov random field characterization is still employed, except it is used to model phase correlations rather than intensity correlations. Since statistical characteristics of phase are typically quite different to those of intensity, there exists the potential for creating greater discrimination in its feature space. We apply the Wreath Product Transform and use the phase at higher scales to initiate the segmentation process. For textures defined by homogeneous regions of dominant local edges, we see that the new algorithm yields better segmentation than that obtained through conventional multiresolution algorithms based on lowpass data.
Thirty years is long enough: getting beyond C
Authors: Eric Brewer, Jeremy Condit, Bill McCloskey, Feng Zhou
Venue: Proceedings of the 10th conference on Hot Topics in Operating Systems - Volume 10 (2005)

Thirty years after its creation, C remains one of the most widely used systems programming languages. Unfortunately, the power of C has become a liability for large systems projects, which are now focusing on security and reliability. Modern languages and static analyses provide an opportunity to improve the quality of systems software, and yet adoption of these tools has been slow. To address this problem, we propose a new language called Ivy that has an evolutionary path from C. The mechanism for this evolutionary path is a system of extensions and refactorings: extensions augment the language with new features, and refactorings assist the programmer in updating their code to use these new features. Extensions and refactorings have a wide variety of applications, from enforcing memory safety to detecting user/kernel pointer errors. We also demonstrate Macroscope, a tool we have built to enable refactoring of existing C code.
Task Instruction: the largest Influence on Human Operator Motion Control Dynamics
Authors: David A. Abbink
Venue: Proceedings of the Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2007)

The dynamics of the human operator while interacting with a haptic interface are often either neglected or at best modeled as a constant mass-spring-damper model. However, it is well known that humans are able to substantially modify their dynamic behaviour. The goal of this study is to show the extent to which humans can modify their endpoint dynamics while interacting with a haptic manipulator. In an experimental study the endpoint dynamics of the ankle-foot complex were estimated as an admittance using closed-loop identification techniques. Subjects were perturbed with continuous torque perturbations and required to perform three tasks: to maintain a constant position (position task), to maintain a constant force (force task) and to relax. Results indicate that subjects substantially decrease their admittance during a position task compared to a force task (up to a factor of 40 at frequencies below 0.5 Hz.), indicating they could choose to resist the torque perturbations or not. It is concluded that modeling the human as a constant mass-spring-damper system can lead to substantial errors in the design of haptic systems.
Video classification using transform coefficients
Authors: A. Girgensohn
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 06 (1999)

This paper describes techniques for classifying video frames using statistical models of reduced DCT or Hadamard transform coefficients. When decimated in time and reduced using truncation or principal component analysis, transform coefficients taken across an entire frame image allow rapid modeling, segmentation and similarity calculation. Unlike color-histogram metrics, this approach models image composition and works on grayscale images. Modeling the statistics of the transformed video frame images gives a likelihood measure that allows video to be segmented, classified, and ranked by similarity for retrieval. Experiments are presented that show an 87% correct classification rate for different classes. Applications are presented including a content-aware video browser.
Optimistic coalescing for heterogeneous register architectures
Authors: Minwook Ahn, Jooyeon Lee, Yunheung Paek
Venue: ACM SIGPLAN Notices (2007)

In this paper, Optimistic coalescing has been proven as an elegant and effective technique that provides better chances of safely coloring more registers in register allocation than other coalescing techniques. Its algorithm originally assumes homogeneous registers which are all gathered in the same register file. Although this register architecture is still common in most general-purpose processors, embedded processors often contain heterogeneous registers which are scattered in physically different register files dedicated for each dissimilar purpose and use. In this work, we developed a modified algorithm for optimal coalescing that helps a register allocator for an embedded processor to better handle such heterogeneity of the register architecture. In the experiment, an existing register allocator was able to achieve up to 10% reduction in code size through our coalescing, and avoid many spills that would have been generated without our scheme.
Offline delegation
Authors: Arne Helme, Tage Stabell-Kulø
Venue: Proceedings of the 8th conference on USENIX Security Symposium - Volume 8 (1999)

This article describes mechanisms for offline delegation of access rights to files maintained by a distributed "File Repository". The mechanisms are designed for a target environment where personal machines are used at times when critical services, such as authentication and authorization services, are not accessible. We demonstrate how valid delegation credentials can be transferred verbally without the use of shared secrets. Our main result shows that delegation of access rights can be accomplished in a system that uses public-key encryption for secrecy and integrity, without forcing the user to rely on a trusted third party, and without requiring connection to the infrastructure. The implementation runs on a contemporary Personal Digital Assistant (PDA); the performance is satisfactory.
Maintaining QoS During Handover Among Multiple Wireless Access Technologies
Authors: David J. Wright
Venue: Proceedings of the International Conference on the Management of Mobile Business (2007)

This paper presents a comparative analysis of alternative approaches that have been developed by IEEE, 3GPP and others for handover of PSTN and Internet sessions among multiple wireless technologies including UMTS, WiFi, WiMAX, Mobile-Fi and WPANs. It evaluates these approaches from the viewpoint of provision of QoS, Quality of Service, for seamless handover of voice, videophone, gaming, audio/video streaming and file download, and shows how QoS at the IP layer can be interworked with QoS at the wireless link layers to provide the QoS required by the user application. The method is illustrated by examples of video streaming and voice over IP.
Putting the science into computer science: treating introductory computer science as the study of algorithms
Authors: Justin Solomon
Venue: ACM SIGCSE Bulletin (2007)

This paper describes why the study of algorithms should be a fundamental component of the standard introductory computer science (CS) curriculum. By shifting the focus of basic CS classes from implementation to concept, educators can greatly enhance student understanding and course relevance despite rapidly-changing paradigms, technologies, and programming languages. Teaching algorithms also encourages the development of other more generalized skills, including the scientific method, problem-solving, modeling, and technical communication.
Concepts and models for typing events for event-based systems
Authors: Szabolcs Rozsnyai, Josef Schiefer, Alexander Schatten
Venue: Proceedings of the 2007 inaugural international conference on Distributed event-based systems (2007)

Event-based systems are increasingly gaining widespread attention for applications that require integration with loosely coupled and distributed systems for time-critical business solutions. In this paper, we show concepts and models for representing, structuring and typing events. We discuss existing event models in the field and introduce the event model of the event-based system SARI for illustrating various typing concepts. The typing concepts cover topics such as type inheritance and exheritance, dynamic type inferencing, attribute types, as well as the extendibility and addressability of events. We show how the typing concepts evolved and depend on the implemented event-based systems which use different approaches for the event processing such as graphical approaches, or approaches, that use Java code, SQL code, or ECA (event-condition-action) rules.