ppxscal/embedding_network huggingface dataset:
Analysis of an algorithm for distributed recognition and accountability
Authors: Calvin Ko, Deborah A. Frincke, Terrance Goan,  Jr., Todd Heberlein, Karl Levitt, Biswanath Mukherjee, Christopher Wee
Venue: Proceedings of the 1st ACM conference on Computer and communications security (1993)

Computer and network systems are vulnerable to attacks. Abandoning the existing huge infrastructure of possibly-insecure computer and network systems is impossible, and replacing them by totally secure systems may not be feasible or cost effective. A common element in many attacks is that a single user will often attempt to intrude upon multiple resources throughout a network. Detecting the attack can become significantly easier by compiling and integrating evidence of such intrusion attempts across the network rather than attempting to assess the situation from the vantage point of only a single host. To solve this problem, we suggest an approach for distributed recognition and accountability (DRA), which consists of algorithms which &ldquo;process&rdquo;, at a central location, distributed and asynchronous &ldquo;reports&rdquo; generated by computers (or a subset thereof) throughout the network. Our highest-priority objectives are to observe ways by which an individual moves around in a network of computers, including changing user names to possibly hide his/her true identity, and to associate all activities of multiple instances of the same individual to the same networkwide user. We present the DRA algorithm and a sketch of its proof under an initial set of simplifying albeit realistic assumptions. Later, we relax these assumptions to accommodate pragmatic aspects such as missing or delayed &ldquo;reports&rdquo;, clock skew, tampered &ldquo;reports&rdquo;, etc. We believe that such algorithms will have widespread applications in the future, particularly in intrusion-detection systems.
Parallel solutions to geometric problems in the scan model of computation
Authors: Guy E. Blelloch, James J. Little
Venue: Journal of Computer and System Sciences (1994)

This paper describes several parallel algorithms that solve geometric problems. The algorithms are based on a vector model of computation-the scan model. The purpose of this paper is both to show how the model can be used and to formulate a set of practical algorithms. The scan model is based on a small set of operations on vectors of atomic values. It differs from the P-RAM models both in that it includes a set of scan primitives, also called parallel prefix computations, and in that it is a strictly data-parallel model. A very useful abstraction in the scan model is the segment abstraction, the subdivision of a vector into a collection of independent smaller vectors. The segment abstraction permits a clean formulation of divide-and-conquer algorithms and is used heavily in the algorithms described in this paper. Within the scan model, using the operations and routines defined, the paper describes a k-D tree algorithm requiring O(lg n) calls to the primitives for n points, a closest-pair algorithm requiring O(lg n) calls to the primitives, a line-drawing algorithm requiring O(1) calls to the primitives, a line-of-sight algorithm requiring O(1) calls to the primitives, and finally, three different convex-hull algorithms. The last convex-hull algorithm, merge-hull, utilizes a generalized binary search technique using divide-and-conquer with the segment abstraction. The paper also describes how to implement the CREW version of Cole's merge sort in O(lg n) calls to the primitives. All these algorithms should be noted for their simplicity rather than their complexity; many of them are parallel versions of known serial algorithms. Most of the algorithms discussed in this paper have been implemented on the Connection Machine, a highly parallel single instruction multiple data computer.
Survey of commercial parallel machines
Authors: Gowri Ramanathan, Joel Oren
Venue: ACM SIGARCH Computer Architecture News (1993)

We have presented in this paper the survey of the parallel machines that are marketed today. The survey includes the latest machines available from Kendell Square Research, Thinking Machines Corporation, MasPar Computer Corporation, NCUBE Corporation, Sequent Computer Systems and Parsytec. We have provided the topology, architecture, cache coherence, synchronization and performance in MFLOPs for each of the machines subject to the availability of information.
Verification of proofs for the B formal development process
Authors: Babak Dehbonei, Fernando Mejia
Venue: ACM SIGPLAN Notices (1993)

Formal methods are more frequently used in the realization of industrial safety-critical systems[10]. From the specification to the code, through a refinement process, all the steps are mathematically proved, generally with the help of automatic tools such as provers. This paper addresses the problem of the verification of such tools in the framework of the B formal development technique. The tools are written in a language called Theory Language for which the basic proof mechanism is pattern-matching. We propose a technique, based on a unification mechanism, for verifying programs written in this language. Some figures concerning the experimentation of this technique on real-life programs are given.
Group structured linear cellular automata over Zm
Authors: Tadakazu Sato
Venue: Journal of Computer and System Sciences (1994)

In this paper, we introduce group structured linear cellular automata which appear naturally in the process of finding their inverse automata and show that the set of local maps of such automata forms a group with the star operation and the problem of finding its inverse linear cellular automaton can be reduced to that of finding its inverse element of the group. Furthermore, it is shown that such groups regardless of their scopes are isomorphic to each other.
Anonymous collaboration: an alternative technique for working together
Authors: Andrew Lee
Venue: ACM SIGCHI Bulletin (1994)

This paper describes an alternative technique for groups to work together, based on anonymity. This is viewed as an alternative to the common direct interaction approach where group members interact with one another at a personal level. Human interaction problems such as over or lack of participation, narrow-mindedness, and personal biases are unavoidable when people work together directly. These problems are the reactions of people when they face others with differences to themselves. It is believed that an alternative interaction technique is needed to solve or reduce the human interaction problems in groups.The philosophy behind the proposed anonymous collaboration (ANOC) technique is to create an environment where collaborators share information and work, without knowing each others' identity or contributions. This kind of human interaction is seen as suppressing direct contact and therefore, also suppressing problems related to human interpersonal interaction. ANOC implementations require the following provisions: anonymity of collaborators and contributions; presence of facilitators; broadcast dialogues; and individual but shared work. Possible implementation scenarios in the areas of electronic discussions, electronic conferencing, and group authoring, are described.ANOC is seen as an alternative especially for groups with members that have conflicting interest and personality, or where equal contribution from everyone is highly regarded.
A New Algorithm for Interactive Graphics on Multicomputers
Authors: David A. Ellsworth
Venue: IEEE Computer Graphics and Applications (1994)

As nonshared-memory multiple instruction, multiple data (MIMD) systems become more common, it becomes important to develop parallel rendering algorithms for them. These systems, known as multicomputers, can produce data sets so large that it is difficult to visualize the data on conventional graphics systems, especially if the visualization proceeds in tandem with the calculation. Parallel systems must run interactive graphics to allow convenient visualizations of their computations. While few parallel systems currently have a frame buffer that will support interactive rendering, such systems should be more common in the future. This article describes an algorithm suited for interactive polygon rendering, where the model's image on screen generally has frame-to-frame coherence. The algorithm uses this coherence to perform load-balancing calculations in parallel with the other calculations. The algorithm also uses an optimized version of personalized all-to-all communication, where all processors communicate with all other processors.
Approximating center points with iterated radon points
Authors: K. L. Clarkson, David Eppstein, Gary L. Miller, Carl Sturtivant, Shang-Hua Teng
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

We describe a practical and provably good algorithm for approximating center points in any number of dimensions. Here c is a center point of a point set P in Rd if every closed halfspace containing c contains at least P/d+1 points of P. Our algorithm has a small constant factor and is the first approximate center point algorithm whose complexity is subexponential in d. Moreover, it can be optimally parallelized to require Olog2 dloglogn time. Our algorithm has been used in mesh partitioning methods, and has the potential to improve results in practice for constructing weak &egr;-nets and other geometric algorithms. We derive a variant of our algorithm with a time bound fully polynomial in d, and show how to combine our approach with previous techniques to compute high quality center points more quickly.
Exact transversal hypergraphs and application to Boolean &mgr;-functions
Authors: Thomas Eiter
Venue: Journal of Symbolic Computation (1994)

Call an hypergraph, that is a family of subsets (edges) from a finite vertex set, an exact transversal hypergraph iff each of its minimal traversals, i.e., minimal vertex subsets that intersect each edge, meets each edge in a singleton. We show that such hypergraphs are recognizable in polynomial time and that their minimal transversals as well as their maximal independent sets can be generated in lexicographic order with polynomial delay between subsequent outputs, which is impossible in the general case unless P=NP. The results obtained are applied to monotone Boolean &mgr;-functions, that are Boolean functions defined by a monotone Boolean expression (that is, built with &and;,&or; only) in which no variable occurs repeatedly. We also show that recognizing such functions from monotone Boolean expressions is co-NP-hard, thus complementing Mundici's result that this problem is in co-NP. &mdash;Author's Abstract
Highly Symmetric Subgraphs of Hypercubes
Authors: A. E. Brouwer, I. J. Dejter, C. Thomassen
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

Two questions are considered, namely (i) How many colors are needed for a coloring of the n-cube without monochromatic quadrangles or hexagons? We show that four colors suffice and thereby settle a problem of Erd&ouml;s. (ii) Which vertex-transitive induced subgraphs does a hypercube have? An interesting graph has come up in this context: If we delete a Hamming code from the 7-cube, the resulting graph is 6-regular, vertex-transitive and its edges can be two-colored such that the two monochromatic subgraphs are isomorphic, cubic, edge-transitive, nonvertex-transitive graphs of girth 10.
Analysis of Or-parallel execution models
Authors: Gopal Gupta, Bharat Jayaraman
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1993)

We discuss fundamental limitations of or-parallel execution models of nondeterministic programming languages. Or-parallelism corresponds to the execution of different nondeterministic computational paths in parallel. A natural way to represent the state of (parallel) execution of a nondeterministic program is by means of an or-parallel tree. We identify three important criteria that underlie the design of or-parallel implementations based on the or-parallel tree: constant-time access to variables, constant-time task creation, and constant-time task switching, where the term constant-time means that the time for these operations is independent of the number of nodes in the or-parallel tree, as well as the size of each node. We prove that all three criteria cannot be simultaneously satisfied by any or-parallel execution model based on a finite number of processors but unbounded memory. We discuss in detail the application of our result to the class of logic programming languages and show how our result can serve as a useful way to categorize the various or-parallel methods proposed in this field. We also discuss the suitability of different or-parallel implemenation strategies for different parallel architectures.
Computer human resource planning for a developing country
Authors: Srisakdi Charmonman, Somsong Chiraphadhanakul
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

Rapid computerization in developing countries have made it necessary for them to study computer-related human resource requirements. Without proper planning, the undesirable problems associated with either shortage or oversupply of computer professionals would probably occur. The case of Thailand will be presented as an example of developing countries. In Thailand in the last five years, the number of computers has increased from 70,000 to 400,000 or over 500%. Shortages of computer professionals have been felt in both the private and public sectors. The Thai study is presented in this paper by starting from an account of computerization in Thailand, hardware and software situations, and production of computer professionals. Then a planning model is proposed for making projection of the required number of computer-related graduates for the next 10 years classified into four groups, namely, computer production industry, computer service industry, computer users, and research and development industry. The proposed computer human resource requirement planning model will be presented to the Thai government to use in approving and supporting computer-related curricula. Other developing countries may also use it as a starting point for their own studies.
Designing information systems for changing organizations
Authors: Hannu Salmela
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

Information systems are nowadays developed and implemented in organizations flavored by changes in their environment and work practices. For information systems (IS) developers this is reflected in terms of changes in the information needs of users during the development phase, increased requests for adaptive maintenance and sometimes in abandonment of a systems as &ldquo;useless for the current situation&rdquo;. These issues are often not considered to be the responsibility of IS developers, or simply seen as unfortunate facts of life. This paper takes a different view. If the analyst is able to provoke discussion concerning changes in the user organization, s/he may not only be able to avoid the aforementioned difficulties, but may also be able to bring added value to the organization by supporting desired changes through IS design. This type of thinking has already been adopted in many of the methods used in strategic IS planning. The method presented in this paper is meant to be used in the process of analyzing user requirements in an individual IS project. It also provides rough guidelines for choosing between alternative design options during systems development. The method is illustrated in use by descriptions of three action research projects. In each project the role of IS in relation to changes in the user organization was analyzed, and advice was given on the client's specific IS problems. The advice was both understood and accepted by decision makers in each client organization.
CSCW for Film and TV Preproduction
Authors: Eric Gidney, Annmarie Chandler, Greg McFarlane
Venue: IEEE MultiMedia (1994)

During preproduction, film and television companies consider visuals in deciding on cast, location, and special effects. Using telecommunications would allow these decision makers to confer at a distance, reducing travel and delays caused by shipping materials back and forth. To support preproduction, an interdisciplinary team developed a prototype computer supported cooperative work application, implemented on Telstra's experimental multimedia communications platform, and demonstrated it to major Australian film and television companies.
Recollections about the development of Pascal
Authors: N. Wirth
Venue: The second ACM SIGPLAN conference on History of programming languages (1993)

Pascal was defined in 1970 and, after a slow start, became one of the most widely used languages in introductory programming courses. This article first summarises the events leading to Pascal's design and implementation, and then proceeds with a discussion of some of the language's merits and deficiencies. In the last part, developments that followed its release are recounted. Its influence chiefly derived from its being a vehicle for structured programming and a basis for further development of languages and for experiments in program verification.
Automated interface code generation from Ada specifications
Authors: Paul R. Pukite
Venue: ACM SIGAda Ada Letters (1993)

Mapping data structures between incompatible representations remains an error-prone and tedious part of program development. This letter outlines a method for automating interface code generation based on Ada package specifications and the use of Ada keywords as interface mapping directives. This concept supports information hiding by placing the details of the generated interface code in the package body.
A mathematical framework to implement statistical databases
Authors: Miro Costa
Venue: ACM SIGSAC Review (1994)

The objective of this paper is to define a mathematical framework for statistical Databases (SDB) and to show how it can be implemented. Matrix algebra is used as a tool in the representation of statistical databases. The matrix algebra operations are considered the building blocks for the implementation of inference control methods. The rigor of this approach can be very beneficial for further studies on this topic. The implementation of Inference Control Methods for SDBs can be greatly simplified if this approach is used. Inference Control methods release aggregate information from a SDB about large subsets of records in a form that attempts to protect individual privacy. The implementation of specific Inference Control Methods (ICM) will be presented in a future publication. Several examples of typical operations on SDBs are presented in the text. SAS/IML was used to implement the ideas proposed here. The samples were prepared and tested using a personal computer (486 IBM/PC compatible) and a mainframe (IBM 4381) available at CSU, Chico.
Writing efficient Smalltalk programs (abstract)
Authors: Ken Auer
Venue: Addendum to the proceedings on Object-oriented programming systems, languages, and applications (Addendum) (1992)

Writing Efficient Smalltalk Programs Ken Auer, Knowledge Systems Corp. Smalltalk has a reputation for being slow and a offers many ways to create inefficient code, and memory hog. In reality, the Smalltalk environment programmers often exploit those opportunities. However, there are just as many ways to create efficient code, some of which may not be available in more traditional languages. Whether an application is efficient or not has more to do with the way the programmer has used the available tools than the tools themselves. This tutorial teaches Smalltalk programmers how to write efficient programs. The emphasis is on how to exploit, rather than sacrifice, the benefits of good object-oriented design. You should have at least six months experience with Smalltalk writing non-toy programs to get the most benefit from the tutorial.
The scheme of things: implementing lexically scoped macros
Authors: Jonathan Rees
Venue: ACM SIGPLAN Lisp Pointers (1993)

I have been hearing some complaints that Scheme's new lexically scoped macro facility is difficult to implement. There are two components to the proposal: the pattern language and lexical scoping. The two pose independent problems. I agree that the ellipsis-enriched pattern language can be tricky to implement; implementations that I have seen take anywhere from 250 to 1400 lines of Scheme code. However, I believe that it is conceptually straightforward, and several implementations have been around for many years (see [9]). On the other hand, many people are unnecessarily getting tripped up on lexical scoping, which, unlike the pattern matcher, is very simple to implement.
Applications of graph drawing to software engineering (abstract)
Authors: Carlo Batini
Venue: ACM SIGACT News (1993)

Several conventions for drawing rooted trees are discussed: classical drawings, tip-over drawings, inclusion drawings, and h-v drawings. In each convention, a number of algorithms and complexity results are available. For free trees (no specific root), algorithms are mostly drawn from folklore. Radial drawings, spring drawings, and orthogonal drawings are discussed.
VODAK open nested transactions&mdash;visualizing database internals
Authors: Peter Muth, Thomas C. Rakow
Venue: Proceedings of the 1993 ACM SIGMOD international conference on Management of data (1993)

VODAK is a prototype of an object-oriented, distributed database system developed during the past five years at the Integrated Publication and Information Systems Institute (IPSI). The aim of demonstrating VODAK Open Nested Transactions is to provide insights into internals of database systems that are usually hidden from application programmers and users. By utilizing semantics of methods, VODAK Open Nested Transactions increase the degree of parallelism between concurrent transactions compared to conventional transaction management schemes. Demonstrating the difference in parallelism provides users with a &ldquo;feeling&rdquo; for internal database mechanisms, application programmers with information about the impact of transaction management on performance, and system developers with ideas how to improve their systems with respect to transaction management.
Principles, techniques, and ethics of stage magic and their application to human interface design
Authors: Bruce Tognazzini
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

Magicians have been designing and presenting illusions for 5000 years. They have developed principles, techniques and ethical positions for their craft that this paper argues are applicable to the design of human/computer interfaces. The author presents a number of specific examples from magic and discusses their counterparts in human interface design, in hopes that human interface practitioners and researchers will, having recognized the applicability of magic, go further on their own to explore its domain.
Constraints on synchronizing oscillator networks
Authors: David E. Cairns, Roland J. Baddeley, Leslie S. Smith
Venue: Neural Computation (1993)

This paper investigates the constraints placed on some synchronized oscillator models by their underlying dynamics. Phase response graphs are used to determine the phase locking behaviors of three oscillator models. These results are compared with idealized phase response graphs for single phase and multiple phase systems. We find that all three oscillators studied are best suited to operate in a single phase system and that the requirements placed on oscillatory models for operation in a multiple phase system are not compatible with the underlying dynamics of oscillatory behavior for these types of oscillator models.