ppxscal/embedding_network huggingface dataset:
Analysis of a mobile communication security protocol
Authors: Tom Coffey, Reiner Dojen
Venue: Proceedings of the 1st international symposium on Information and communication technologies (2003)

Cryptographic protocols are used to achieve secure communication over insecure networks. Weaknesses in such protocols are hard to identify, as they can be the result of subtle design flaws. Formal verification techniques provide rigid and thorough means to evaluate security protocols. This paper demonstrates the process of formal verification by applying a logic to a security protocol intended for use in mobile communications. As a result of the verification, 8 failed protocol goals are identified. Further, a new attack on the protocol is outlined. The presence of weaknesses in published protocols highlights the importance of formal verification to prevent insecure protocols reaching the public domain.
Team structure and team performance in IS development: a social network perspective
Authors: Heng-Li Yang, Jih-Hsin Tang
Venue: Information and Management (2004)

Teamwork during IS development (ISD) is an important issue. This paper discusses the relationship betweer team structure and ISD team performance using a social network approach. Based on empirical evidence collected from 125 teams in a system analysis and design course, we found that: (1) Group cohesion was positively related to overall performance. (2) Group conflict indexes were not significantly correlated with overall performance. (3) Group characteristics, e.g., cohesion and conflict, fluctuated in different phases, but in later stages, much less cohesion occurred and the advice network seemed to be very important. (4) Group structures seemed to be a critical factor for good performance.Further in-depth studies were conducted on teams exhibiting the highest and lowest performance to determine their differences from a sociogram analysis perspective.
Poster abstract: BTnodes -- a distributed platform for sensor nodes
Authors: Jan Beutel, Oliver Kasten, Matthias Ringwald
Venue: Proceedings of the 1st international conference on Embedded networked sensor systems (2003)

We motivate a prototyping platform for ad hoc networking research showing some requirements and constraints. The architecture of the BTnodes, each of which can store information, compute and communicate, is explained in conjunction with some demo applications that have been implemented. Important requirements and design trade-offs to be able to support multiple, compatible communication interfaces, to handle limited resources, for power-aware operation and for efficient testbed deployment are discussed.
A semantics for web services authentication
Authors: Karthikeyan Bhargavan, Cédric Fournet, Andrew D. Gordon
Venue: ACM SIGPLAN Notices (2004)

We consider the problem of specifying and verifying cryptographic security protocols for XML web services. The security specification WS-Security describes a range of XML security tokens, such as username tokens, public-key certificates, and digital signature blocks, amounting to a flexible vocabulary for expressing protocols. To describe the syntax of these tokens, we extend the usual XML data model with symbolic representations of cryptographic values. We use predicates on this data model to describe the semantics of security tokens and of sample protocols distributed with the Microsoft WSE implementation of WS-Security. By embedding our data model within Abadi and Fournet's applied pi calculus, we formulate and prove security properties with respect to the standard Dolev-Yao threat model. Moreover, we informally discuss issues not addressed by the formal model. To the best of our knowledge, this is the first approach to the specification and verification of security protocols based on a faithful account of the XML wire format.
A Diversity-Controlling Adaptive Genetic Algorithm for the Vehicle Routing Problem with Time Windows
Authors: Kenny Q. Zhu
Venue: Proceedings of the 15th IEEE International Conference on Tools with Artificial Intelligence (2003)

This paper presents an adaptive genetic algorithm (GA) to solve the Vehicle Routing Problem with Time Windows (VRPTW) to near optimal solutions. The algorithm employs a unique decoding scheme with the integer strings. It also automatically adapts the crossover probability and the mutation rate to the changing population dynamics. The adaptive control maintains population diversity at user-defined levels, and therefore prevents premature convergence insearch. Comparison between this algorithm and a normal fixed parameter GA clearly demonstrates the advantage of population diversity control. Our experiments with the 56 Solomon benchmark problems indicate that this algorithm is competitive and it paves way for future research on population-based adaptive genetic algorithm.
On the improvement of anthropometry and pose estimation from a single uncalibrated image
Authors: Carlos Barrón, Ioannis A. Kakadiaris
Venue: Machine Vision and Applications (2003)

Recently, we developed a technique that allows semi-automatic estimation of anthropometry and pose from a single image. However, estimation was limited to a class of images for which an adequate number of human body segments were almost parallel to the image plane. In this paper, we present a generalization of that estimation algorithm that exploits pairwise geometric relationships of body segments to allow estimation from a broader class of images. In addition, we refine our search space by constructing a fully populated discrete hyper-ellipsoid of stick human body models in order to capture the variance of the statistical anthropometric information. As a result, a better initial estimate can be computed by our algorithm and thus the number of iterations needed during minimization are reduced tenfold. We present our results over a variety of images to demonstrate the broad coverage of our algorithm.
Clique family inequalities for the stable set polytope of quasi-line graphs
Authors: G. Oriolo
Venue: Discrete Applied Mathematics (2003)

In one of fundamental works in combinatorial optimization, Edmonds gave a complete linear description of the matching polytope. Matchings in a graph are equivalent to stable sets in its line graph. Also the neighborhood of any vertex in a line graph partitions into two cliques: graphs with this latter property are called quasi-line graphs. Quasi-line graphs are a subclass of claw-free graphs, and as for claw-free graphs, there exists a polynomial algorithm for finding a maximum weighted stable set in such graphs, but we do not have a complete characterization of their stable set polytope (SSP). In the paper, we introduce a class of inequalities, called clique-family inequalities, which are valid for the SSP of any graph and match the odd set inequalities defined by Edmonds for the matching polytope. This class of inequalities unifies all the known (non-trivial) facet inducing inequalities for the SSP of a quasi-line graph. We, therefore, conjecture that all the non-trivial facets of the SSP of a quasi-line graph belong to this class. We show that the conjecture is indeed correct for the subclasses of quasi-line graphs for which we have a complete description of the SSP. We discuss some approaches for solving the conjecture and a related problem.
The social construction of the software operation: reinforcing effects in metrics programs
Authors: Helle Damborg Frederiksen, Jeremy Rose
Venue: Scandinavian Journal of Information Systems (2003)

In a large software company in Denmark, much effort was expended capturing metrics about the company's software operation. The purpose of the metrics program was to change and improve the software operation. Writing software can be understood as socially constructed practice, which can be analyzed using structuration theory. This structurational analysis showed that the company's software operation followed an easily recognizable and widely understood pattern. The software operation was organized in terms of development projects leading to applications that then needed maintenance, and displayed a heavy focus on project development work and hitting the project deadline. Study of the metrics program (and the computer software underpinning it) revealed that the familiar pattern was also inscribed into the metrics software, heavily influencing the company's metrics practice. Rather than challenge the underlying social practice of the software operation, the metrics program reinforced it by adopting the same underlying values. Our conclusion is that, under these circumstances, metrics programs are unlikely to result in radical changes to the software operation, and are best suited to small, incremental improvements.
Containment and equivalence for a fragment of XPath
Authors: Gerome Miklau, Dan Suciu
Venue: Journal of the ACM (JACM) (2004)

XPath is a language for navigating an XML document and selecting a set of element nodes. XPath expressions are used to query XML data, describe key constraints, express transformations, and reference elements in remote documents. This article studies the containment and equivalence problems for a fragment of the XPath query language, with applications in all these contexts.In particular, we study a class of XPath queries that contain branching, label wildcards and can express descendant relationships between nodes. Prior work has shown that languages that combine any two of these three features have efficient containment algorithms. However, we show that for the combination of features, containment is coNP-complete. We provide a sound and complete algorithm for containment that runs in exponential time, and study parameterized PTIME special cases. While we identify one parameterized class of queries for which containment can be decided efficiently, we also show that even with some bounded parameters, containment remains coNP-complete. In response to these negative results, we describe a sound algorithm that is efficient for all queries, but may return false negatives in some cases.
Untestable Fault Identification using Recurrence Relations and Impossible Value Assignments
Authors: Manan Syal, Michael S. Hsiao
Venue: Proceedings of the 17th International Conference on VLSI Design (2004)

This paper presents two novel and low cost techniques that can beused for the purpose of untestable fault identification. First, wepresent a new theorem and a practical method using staticimplications to identify unexcitable nets using recurrencerelations in sequential circuits. Since each unexcitable netgenerally infers to more than one untestable fault, this theoremhelps us to quickly identify significantly more sequentiallyuntestable faults. In addition to discovering unexcitable nets usingrecurrence relations, we propose a second approach that aims atquickly identifying non-trivial multiple-node conflicts, which canthen be used to identify additional untestable faults in bothcombinational and sequential circuits. Unlike previous techniquesthat concentrate on identifying local conflicts in the circuit, ourapproach efficiently extends the conflicting value analysis acrossmultiple levels in the circuit to identify more untestable faults.Application of our techniques to both combinational andsequential benchmark circuits showed that significantly moreuntestable faults can be identified using the proposed approaches,with low overhead in terms of both memory and execution time.
Adaptive Inventory Control for Nonstationary Demand and Partial Information
Authors: James T. Treharne, Charles R. Sox
Venue: Management Science (2002)

This paper examines several different policies for an inventory control problem in which the demand process is nonstationary and partially observed. The probability distribution for the demand in each period is determined by the state of a Markov chain, the core process. However, the state of this core process is not directly observed, only the actual demand is observed by the decision maker. Given this demand process, the inventory control problem is a composite-state, partially observed Markov decision process (POMDP), which is an appropriate model for a number of dynamic demand problems. In practice, managers often use certainty equivalent control (CEC) policies to solve such a problem. However, this paper presents results that demonstrate that there are other practical control policies that almost always provide much better solutions for this problem than the CEC policies commonly used in practice. The computational results also indicate how specific problem characteristics influence the performance of each of the alternative policies.
Protein folding simulations using the activation-relaxation technique
Authors: G. Wei, N. Mousseau, P. Derreumaux
Venue: Proceedings of the international conference on Computational methods in sciences and engineering (2003)

Understanding folding mechanisms by which proteins find their native and functional forms is a crucial issue in the post-genomic era. Molecular dynamics and Monte Carlo simulations are often used to simulate the folding process. Here we show that the activitation relaxation technique allows for the discovery of new folding mechanims for simple protein models.
Fast functional evaluation of candidate OBDD variable orderings
Authors: Don E. Ross, Kenneth M. Butler, Rohit Kapur, M. Ray Mercer
Venue: Proceedings of the conference on European design automation (1991)

Symbolic simulation via Ordered Binary Decision Diagrams (OBDDs) is becoming more feasible each year. These representations are often very efficient under an appropriate ordering of the variables of the functions represented. Recently, heuristics for ordering variables have been developed, but due to the nature of heuristics, no single heuristic always produces an appropriate ordering. We develop and analyze a technique for selecting the best of several candidate orderings. Our ordering selection method is fast. Its ranking of an ordering is compared to the actual performance of an ordering during functional (OBDD) calculations in circuits from the ISCAS85 combinational benchmarks. Compared to any previously published single ordering heuristic, our method allows OBDD calculations using less cumulative memory over all six circuits investigated, and also produces over an order of magnitude improvement for one or more of those circuits, over every single heuristic examined.
Developing a wider view of educational technology through ubiquitous computing: a qualitative case study
Authors: Donald Bruce Curry
Venue:  (2003)

Ubiquitous computing in elementary schools is in its early phases of development. However, many signs point to the likelihood that some form of one-to-one personal computing in schools is inevitable in the near future. The research pertaining to this model of computing technology is relatively scarce, leaving schools with a knowledge void when attempting to make decisions pertaining to this paradigm. The investigation sought to help alleviate this gap in the knowledge base by providing a qualitative case study that examined an elementary school's wireless laptop program over an extended period of one and one-half years. It gathered and described basic information about this model of technology in education and helped form a database for future comparison and/or theory building related to ubiquitous computing. Additionally, the relationship between identifying/removing barriers to technology use and developing a wider view of educational computing among members of the school community was examined. The theoretical purpose of the investigation explored how participants in the program developed a wider view of educational computing, which was defined as the processes by which individuals come to understand how technology can enhance the school environment. The more basic purposes were threefold: to describe richly what occurred as this school made the transition to ubiquitous computing, to interpret inductively the findings into a series of lessons learned from the experience, and to apply practically the findings to the future direction of the program. The qualitative inquiry into this laptop program employed an embedded single-case study design to achieve the stated purposes and made use of a variety of data-gathering strategies (interviews, observations, and document analysis), consistent with the investigator's goals. By advancing our understanding of the processes by which people come to use ubiquitous computing to empower teaching and learning, this research made a substantial contribution to knowledge and practice. Its timing relative to this paradigm's entry into schools gives it the potential to have a disproportionately significant impact on the model's development.
Efficient Computation of Aggregate Structural Joins
Authors: Kaiyang Liu, Fred H. Lochovsky
Venue: Proceedings of the Fourth International Conference on Web Information Systems Engineering (2003)

Although several XML query-processing techniques have been proposed to do structural joins, no work has been done to handle aggregate structural join, which computes the aggregate value for two given XML element sets. One important kind of aggregate structural join is to determine the exact selectivity of a structural join, which proves to be crucial for overall path expression optimization and on-line systems. Related work has been done to estimate the selectivity of a path expression by applying summary techniques for XML data based on either tree simplification or a Markov model. However, because of either space restrictions or performance issues (for example, previous approaches may need to store thewhole XML tree to answer an aggregate structural join), they are not applicable for aggregate structural joins. In this paper, we consider a modified aggregate B+-tree, which we call a XA-tree, to index the aggregate attribute values of XML elements. Since it is based on the B+-tree, the XA-tree supports query and update efficiently and places little additional burden on database administrators. Two basic algorithms are proposed to compute aggregate structural joins efficiently by utilizing the XA-tree. Furthermore, a heuristic is also proposed that helps to further improve the performance significantly. Extensive experiments have confirmed that our approaches greatly outperform competitors by an order of magnitude.
Evaluation of key frame-based retrieval techniques for video
Authors: Marcus J. Pickering, Stefan Rüger
Venue: Computer Vision and Image Understanding (2003)

We investigate the application of a variety of content-based image retrieval techniques to the problem of video retrieval. We generate large numbers of features for each of the key frames selected by a highly effective shot boundary detection algorithm to facilitate a query by example type search. The retrieval performance of two learning methods, boosting and k-nearest neighbours, is compared against a vector space model. We carry out a novel and extensive evaluation to demonstrate and compare the usefulness of these algorithms for video retrieval tasks using a carefully created test collection of over 6000 still images, where performance is measured against relevance judgements based on human image annotations. Three types of experiment are carried out: classification tasks, category searches (both related to automated annotation and summarisation of video material) and real world searches (for navigation and entry point finding). We also show graphical results of real video search tasks using the algorithms, which have not previously been applied to video material in this way.
A Tabu-Search Hyperheuristic for Timetabling and Rostering
Authors: E. K. Burke, G. Kendall, E. Soubeiga
Venue: Journal of Heuristics (2003)

Hyperheuristics can be defined to be heuristics which choose between heuristics in order to solve a given optimisation problem. The main motivation behind the development of such approaches is the goal of developing automated scheduling methods which are not restricted to one problem. In this paper we report the investigation of a hyperheuristic approach and evaluate it on various instances of two distinct timetabling and rostering problems. In the framework of our hyperheuristic approach, heuristics compete using rules based on the principles of reinforcement learning. A tabu list of heuristics is also maintained which prevents certain heuristics from being chosen at certain times during the search. We demonstrate that this tabu-search hyperheuristic is an easily re-usable method which can produce solutions of at least acceptable quality across a variety of problems and instances. In effect the proposed method is capable of producing solutions that are competitive with those obtained using state-of-the-art problem-specific techniques for the problems studied here, but is fundamentally more general than those techniques.
The influences of the degree of interactivity on user-outcomes in a multimedia environment: an empirical investigation
Authors: William D. Haseman, Vichuda Nui Polatoglu, K. Ramamurthy
Venue: Advanced topics in information resources management (2003)

The study reported here investigates the influence of "interactivity" on the learning outcomes of users in a multimedia systems environment. Drawing from past literature base and based on key tenets of three learning theories, behaviorist, cognitivist and constructivist, the study first proposes a measurement scheme for "interactivity" and then hypothesizes that "interactivity" would influence the learning outcomes positively in terms of users' learning achievement and attitude. Three prototypes of a multimedia instructional/ training system to represent high, low, and non-interactive modes of use were developed and implemented, and the hypothesized influences were investigated using a controlled laboratory research design. Multiple analysis of variance (MANOVA) results indicate that while interactivity does not necessarily enable enhanced gain in user learning, it positively influences participants' attitude. The study finds no support for hypothesized moderating effects of learning styles (measured using Kolb's Learning Style Inventory scale) on the relationship between interactivity and user outcomes. The results of this study have important implications for both education and corporations' training efforts and investments. The reasons for practical lack of influence of learning style are highlighted in some detail. Implications and future research directions are discussed.
Natural communities in large linked networks
Authors: John Hopcroft, Omar Khan, Brian Kulis, Bart Selman
Venue: Proceedings of the ninth ACM SIGKDD international conference on Knowledge discovery and data mining (2003)

We are interested in finding natural communities in large-scale linked networks. Our ultimate goal is to track changes over time in such communities. For such temporal tracking, we require a clustering algorithm that is relatively stable under small perturbations of the input data. We have developed an efficient, scalable agglomerative strategy and applied it to the citation graph of the NEC CiteSeer database (250,000 papers; 4.5 million citations). Agglomerative clustering techniques are known to be unstable on data in which the community structure is not strong. We find that some communities are essentially random and thus unstable while others are natural and will appear in most clusterings. These natural communities will enable us to track the evolution of communities over time.