ppxscal/embedding_network huggingface dataset:
Software model checking: the Bandera approach
Authors: Matthew Dwyer
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

Model checking techniques have been an effective means for finding subtle defects in hardware designs and communication protocols. The increased use of concurrent software in embedded applications and the widespread adoption of Java with its built-in concurrency constructs have led researchers to attempt to adapt model-checking techniques to software. To date, this effort has been hindered by several obstacles including construction of correct tractable models from programs with enormous state spaces, appropriate specification of checkable software requirements, and interpretation of long, and potentially abstract, counterexample traces.In this talk, we describe Bandera --an integrated collection of tools for model-checking concurrent Java software that attempts to overcome the obstacles described above. Bandera is a model compiler in the sense that it takes Java source code as input and compiles it to a program model expressed in the input language of one of several existing verification tools including Spin, dSpin, and JPF. Program slicing and abstract interpretation components are used during compilation to customize the program model with respect to the properties being checked. Bandera is like a debugger in the sense that it maps counterexamples produced by back-end model checkers back to the source code level, and it allows the user to replay program execution both forwards and backwards along the path of the counterexample.We will present an overview of several case studies using Bandera that provide positive evidence of the effectiveness of model checking realistic properties of non-trivial concurrent software. These case studies also point out the need for additional functionality to enable scaling of software model checking to even larger and more complex systems. Finally, we conclude with a description of the latest public release of the Bandera toolset and our plans for future functionality.
Us Airways Automates its Weekend Fleet Assignment
Authors: Spyros Kontogiorgis, Suresh Acharya
Venue: Interfaces (1999)

Assigning fleets of aircraft to a weekend schedule is more difficult than assigning them to a weekday schedule. The reason is that we must balance two conflicting objectives. We must meet passenger demand that is different from weekday demand. We must also minimize the costs of realigning airport facilities and personnel that we would incur by changing flight patterns too much. To support US Airways schedule planners in this balancing act, we built a specialized fleet-assignment model and integrated it into a graphical environment for schedule development. The planners use the system to create safe, profitable, and robust flight plans.
An improved sequential method for principal component analysis
Authors: Ze Wang, Yin Lee, Simone Fiori, Chi-Sing Leung, Yi-Sheng Zhu
Venue: Pattern Recognition Letters (2003)

In sequential principal component (PC) extraction, when increasing numbers of PCs are extracted the accumulated extraction error becomes dominant and makes a reliable extraction of the remaining PCs difficult. This paper presents an improved cascade recursive least squares method for PCs' extraction. The good features of the proposed approach are illustrated through simulation results, and include improved convergence speed and higher extraction accuracy.
Scalable directory services using proactivity
Authors: Fabián E. Bustamante, Patrick Widener, Karsten Schwan
Venue: Proceedings of the 2002 ACM/IEEE conference on Supercomputing (2002)

Common to computational grids and pervasive computing is the need for an expressive, efficient, and scalable directory service that provides information about objects in the environment. We argue that a directory interface that 'pushes' information to clients about changes to objects can significantly improve scalability. This paper describes the design, implementation, and evaluation of the Proactive Directory Service (PDS). PDS' interface supports a customizable 'proactive' mode through which clients can subscribe to be notified about changes to their objects of interest. Clients can dynamically tune the detail and granularity of these notifications through filter functions instantiated at the server or at the object's owner, and by remotely tuning the functionality of those filters. We compare PDS' performance against off-the-shelf implementations of DNS and the Lightweight Directory Access Protocol. Our evaluation results confirm the expected performance advantages of this approach and demonstrate that customized notification through filter functions can reduce bandwidth utilization while improving the performance of both clients and directory servers.
Greedy loop transversal codes for correcting error bursts
Authors: Dug-Hwan Choi, Jonathan D. H. Smith
Venue: Discrete Mathematics (2003)

The greedy loop transversal algorithm is used to construct linear codes in a binary channel for the correction of error bursts. The dimensions of the codes constructed are compared with the dimensions of the corresponding white noise greedy loop transversal codes, and with the dimensions of the few previously best-known codes for the burst-error patterns. The dimensions of the greedy loop transversal codes for burst-error correction match or exceed the dimensions of these previously known codes.
A virtual environment for conceptual design in architecture
Authors: Lee Anderson, James Esser, Victoria Interrante
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

We present a virtual environment application that has been developed for conceptual design in architecture and seeks to emulate aspects of a typical designer's work area. The environment provides a means of creating and manipulating basic geometry using a kiosk toolbox. More importantly, the environment provides simple means for using imagery and videos developed outside of the environment for use within the environment for both information and design. A DesignStation is provided within the environment to create a work area for the designer, concentrating imagery and information associated with the design as well as an area for reflecting upon, presenting and critiquing the design process. A unique aspect of the environment is the ability to work in more than one scale simultaneously.
Bounds for the chromatic number of graphs with partial information
Authors: William C. Coffman, S. Louis Hakimi, Edward Schmeichel
Venue: Discrete Mathematics (2003)

We obtain bounds for the chromatic and clique numbers of a simple graph, first in terms of the number of vertices and edges it contains, and then in terms of its vertex degrees. In every case, we examine the tightness of the bounds we obtain. We also briefly discuss lower bounds for the independence number of a graph in terms of the same parameters.
On using reliable network RAM in networks of workstations
Authors: Sotiris Ioannidis, Athanasios E. Papathanasiou, Grigorios I. Magklis, Evangelos P. Markatos, Dionisios N. Pnevmatikatos, Julia Sevaslidou
Venue: Cluster Computing (2001)

File systems and databases usually make several synchronous disk write accesses in order to make sure that the disk always has a consistent view of their data, and that data can be recovered in the case of a system crash. Since synchronous disk operations are slow, some systems choose to employ asynchronous disk write operations, at the cost of low reliability: in case of a system crash all data that have not yet been written to disk are lost.In this paper we describe a software-based approach into using the network memory in a workstation cluster as a layer of Non-Volatile memory (NVRAM). Our approach takes a set of volatile main memories residing in independent workstations and transforms it into a fault-tolerant memory - much like RAIDS do with magnetic disks. This layer of NVRAM allows us to create systems that combine the reliability of synchronous disk accesses with the cost of asynchronous disk accesses. We demonstrate the applicability of our approach by integrating it into existing database systems, and by developing novel systems from the ground up.We use experimental evaluation using well-known database benchmarks and detailed simulation to characterize the performance of our systems. Our experiments suggest that our approach may improve performance by as much as two orders of magnitude.
Synthesizing experiences: lessons to be learned from internet-mediated simulation games
Authors: Tasia Asakawa, Nigel Gilbert
Venue: Simulation and Gaming (2003)

This article draws on published evaluations of Internet-mediated (I-M) educational, business, and policy games to establish an inventory of lessons for future I-M games. These three types of I-M games have important concerns in common: objectives, role-play, synchronicity, game facilitation, and participant interaction. Lessons of design and implementation derived from these experiences are identified and explored. Special attention is given to the development of strategic I-M policy games because I-M gaming literature has tended to ignore them in comparison with educational and business games, and they seem to require more guidance and support in three main areas: structure, motivation, and interaction.
Estimation of storm water pollution loads in coastal Karstic areas
Authors: J. Margeta, I. Fistanicˇ
Venue: Development and application of computer techniques to environmental studies (2002)

The paper analyses the problem of calculation of the average annual pollution loads of urban area storm water. Without the knowledge of annual pollution load discharged by storm water into water resources, there can be no planning and management of water quality and coastal sea. There are several calculation methods. However, the method of calculation of annual pollution loads has not been developed for Karstic areas; thus a new method named "Split" is proposed. Characteristics of that method are shown in the case study of the Kastela Bay.
On the Effectiveness of Zero-Inventory-Ordering Policies for the Economic Lot-Sizing Model with a Class of Piecewise Linear Cost Structures
Authors: Lap Mui Ann Chan, Ana Muriel, Zuo--Jun Shen, David Simchi--Levi
Venue: Operations Research (2002)

We consider an economic lot-sizing problem with a special class of piecewise linear ordering costs, which we refer to as the class of modified all-unit discount cost functions. Such an ordering cost function represents transportation costs charged by many less-than truckload carriers. We show that even special cases of the lot-sizing problem are NP-hard and therefore analyze the effectiveness of easily implementable policies. In particular, we demonstrate that there exists a zero-inventory-ordering(ZIO) policy, i.e., a policy in which an order is placed only when the inventory level drops to zero, whose total inventory and ordering cost is no more than 4/3 times the optimal cost. Furthermore, if the ordering cost function does not vary over time, then the cost of the best ZIO policy is no more than 5/6 4/6 times the optimal cost. These results hold for any transportation and holding cost functions that satisfy the following properties: (i) they are non decreasing functions, and (ii) the associated cost per unit is non increasing. Finally, we report on a numerical study that shows the effectiveness of ZIO policies on a set of test problems.
Using the web as a collaborative tool
Authors: Sharon Paranto
Venue: Journal of Computing Sciences in Colleges (2002)

This paper describes how the Internet was used as a collaborative tool in a "real-world" website development project, a group project assigned to students taking an Advanced Computer Applications course. Students worked collaboratively in small groups and coordinated with area businesses, both in person and online, to develop interactive websites for the businesses. The ability to temporarily publish the websites to the university's E-learning server meant that students could work on the project at their convenience and the corresponding businesses were able to review the websites and test the interactive forms at their convenience. E-mail also provided a means of communication among group members, as well as between groups and the corresponding organizations for which the groups were developing websites.As the websites were developed, the sponsoring organizations were asked to provide keywords, words that clients would be expected to use in a search for their type of organization or products and services, as well as a short, one-sentence description of the organization. These were sent to the students via e-mail and the students incorporated the keywords and description into the website through the use of META tags. When the websites were approved by the sponsoring organizations, they were published to actual sites and the sites were submitted to search engines. The students also incorporated interactive forms into the websites, thus allowing the organizations to use the Web to communicate with customers and potential clients. As the world becomes more global in nature, the ability to communicate and collaborate without regard to time or place becomes increasingly important. The Web is an inexpensive and easily accessible tool that can be used effectively to enhance collaborative efforts, in both educational applications and commercial and service settings, especially when schedules or logistics are such that in-person meetings are difficult, if not impossible.
Mount Sinai Hospital Uses Integer Programming to Allocate Operating Room Time
Authors: John T. Blake, Joan Donald
Venue: Interfaces (2002)

An integer-programming model and a post-solution heuristic allocates operating room time to the five surgical divisions at Toronto's Mount Sinai Hospital. The hospital has used this approach for several years and credits it with both administrative savings and the ability to produce quickly an equitable master surgical schedule.
Global stability of a two-stage epidemic model with generalized non-linear incidence
Authors: S. M. Moghadas, A. B. Gumel
Venue: Mathematics and Computers in Simulation (2002)

A multi-stage model of disease transmission, which incorporates a generalized non-linear incidence function, is developed and analysed qualitatively. The model exhibits two steady states namely: a disease-free state and a unique endemic state. A global stability of the model reveals that the disease-free equilibrium is globally asymptotically stable (and therefore the disease can be eradicated) provided a certain threshold R0 (known as the basic reproductive number) is less than unity. On the other hand, the unique endemic equilibrium is globally asymptotically stable for R0 > 1.
Fill-Rate Bottlenecks in Production-Inventory Networks
Authors: Paul Glasserman, Yashan Wang
Venue: Manufacturing Service Operations Management (1999)

The bottleneck in a production-inventory network is commonly t aken to be the facility that most limits flow through the network and thus the most highly utilized facility. A further connotation of "bottleneck," however, is the facility that most constrains system-wide performance or the facility at which additional resources would have the greatest impact. Adopting this broader sense of the term, we look for fill-rate bottlenecks: facilities in a production inventory network that most constrain the system-wide fill rate (the proportion of demands filled within a fixed delivery leadtime) or facilities at which either additional production capacity or additional inventory would have the greatest impact on the fill rate. We consider systems in which various components are produced through a series of stages holding intermediate inventories and are then assembled into finished goods to meet external demands. With each station in the network we associate precise measures of the station's propensity to constrain the fill rate. We call a station with a minimal measure a fill-rate bottleneck and justify this label both theoretically and numerically. Examples show that even the least utilized facility can be a fill-rate bottleneck. Unlike utilization, our bottleneck criteria capture information about process variability.
A behavioral simulation tool for continuous-time ΔΣ modulators
Authors: K. Francken, M. Vogels, E. Martens, G. Gielen
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

Circuit--level simulation of &Delta;&Sigma; modulators is a time--consuming task (taking one or more days for meaningful results). While there are a great variety of techniques and tools that speed up the simulations for discrete--time (DT) &Delta;&Sigma; modulators, there is no rigorous methodology implemented in a tool to efficiently simulate and design the continuous--time (CT) counterpart. Yet, in todays low--power, high--accuracy and/or very high--speed demands for A--to--D converters, designers are often forced to resort to the use of CT &Delta;&Sigma; topologies. In this paper, we present a method for the high--level simulation of continuous--time &Delta;&Sigma; modulators that is based on behavioral models and which exhibits the best trade--off between accuracy, speed and extensibility compared to other possible techniques that are reviewed briefly in this work. A user--friendly tool, implementing this methodology, is then presented. Nonidealities such as finite gain, finite GBW, output impedance and also nonlinearities such as clipping, harmonic distortion and the important effect of jitter are modeled. Finally, experiments were carried out using the tool, exploring important design trade--offs.
An affordable optical head tracking system for desktop VR/AR systems
Authors: Jurriaan D. Mulder, Jack Jansen, Arjen van Rhijn
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

We present an affordable optical head tracking system for desktop-like VR/AR environments. The generic and specific head tracking requirements for these type of environments are de ned, as well as the relaxations such environments put on head tracking systems. The presented head tracker is based on two low-cost, commodity FireWire cameras that track a simple 3D dot pattern. It is shown that the tracker provides high accuracy, an update rate of 30 updates per second, a low computational load, and a moderate delay of 66 ms. It is competitive to commercially available, moderate-cost head tracking systems yet for substantially lower costs.
An isomorphic Fourier transform approach to light propagation in AWGs, FBGs, and photonic crystals
Authors: Michael C. Parker, Stuart D. Walker
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

We have identified a comprehensive isomorphism between arrayed-waveguide grating (AWG), fibre Bragg grating (FBG) and photonic crystal (PC) devices, which allows the design characteristics of the former transverse geometry to be mapped on to the latter longitudinal structures. In this paper, we present a unified Fourier transform (FT) approach to the study of these important passive optical grating-based devices.
Explaining cryptographic systems
Authors: Tim Bell, Harold Thimbleby, Mike Fellows, Ian Witten, Neil Koblitz, Matthew Powell
Venue: Computers Education (2003)

Modern cryptography can achieve levels of security and authentication that non-specialists find literally incredible. Techniques including information-hiding protocols, zero-knowledge proofs and public key cryptosystems can be used to support applications like digital signatures, digital cash, on-line poker and secure voting in ways that are provably secure--far more secure than the traditional systems they replace. This paper describes simple versions of such applications that have been used to give school-children and the general public a broad understanding of what can be achieved, and how. The material has been extensively and successfully used by the authors in schools, science festivals and with undergraduates, and even postgraduate specialists.
End-user software visualizations for fault localization
Authors: J. Ruthruff, E. Creswick, M. Burnett, C. Cook, S. Prabhakararao, M. Fisher,  II, M. Main
Venue: Proceedings of the 2003 ACM symposium on Software visualization (2003)

End-user programming has become the most common form of programming today. However, despite this growth, there has been little investigation into bringing the benefits of software visualization to end-user programmers. Evidence from the spreadsheet paradigm, probably the most widely used end-user environment, reveals that end users' programs often contain faults. We would like to integrate software visualization into these end-user environments to help end users deal with the reliability issues in their programs. Towards this end, we have devised several fault localization visualization techniques for spreadsheets. This paper describes these techniques and reports the results of a formative study---using tests created by end users---to investigate how these fault localization techniques compare. Our results reveal some strengths and weaknesses of each technique, and provide insights into the cost-effectiveness of each technique for the interactive world of end-user spreadsheet development.
Standby power optimization via transistor sizing and dual threshold voltage assignment
Authors: Mahesh Ketkar, Sachin S. Sapatnekar
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

This paper presents a novel enumerative approach, with provable and efficient pruning techniques, for dual threshold voltage (Vt) assignment at the transistor level. Since the use of low Vt may entail a substantial increase in leakage power, we formulate the problem as one of combined optimization for leakage-delay tradeoffs under Vt optimization and sizing. Based on an analysis of the effects of these two transforms on the delay and leakage, we justify a two-step procedure for performing this optimization. Results are presented on the ISCAS85 benchmark suite favorably comparing our approach with an existing sensitivity-based optimizer.
Interprovider differentiated service interconnection management models in the internet bandwidth commodity markets
Authors: Junseok Hwang, Hak-Jin Kim, Martin B. H. Weiss
Venue: Telematics and Informatics (2002)

Due to the recent evolution of telecommunications infrastructure and the Internet as a commodity market for bandwidth, Internet Service Providers (ISPs) encounter new issues concerned with bandwidth management for the network interconnection. Bandwidth commodity exchange is considered a new B2B (Business-to-Business) electronic commerce application that brings new market opportunities to carriers and service providers for managing their bandwidth resources. This paper develops market-based bandwidth management optimization models for Differentiated Service (DiffServ) QoS (Quality of Service) networks using an implementation of the bandwidth management agent, BMP (Bandwidth Management Point). We use network economic models to formulate an optimization problem for the interconnection and resource allocation policy of the DiffServ network. We formulate and develop those economic models as optimization problems of LP, NLP, MILP and mixed integer nonlinear programming (MINLP), and discuss the pricing mechanisms and available solution approaches for the implementation of the BMP's resource optimization process. Different opportunity costs are estimated based on the results of a network simulation using traffic flow statistics measured from a recent Internet backbone. We then numerically simulate the behavior of backbone network ISPs to optimize their profits for various demand scenarios.