ppxscal/embedding_network huggingface dataset:
The Difference-Stereogram
Authors: András G. Radványi
Venue: Journal of Mathematical Imaging and Vision (1999)

In simple hypothetical experiments for producing random stereograms by stereo-photographic means together with a pattern projection technique, we arrive at the concept of difference-stereogram showing changes on a surface rather than the surface itself. After the analysis of projector-camera arrangement, an algorithmic definition of difference-stereogram is given, revealing several of its structural properties. The related concept of difference surface is introduced to describe the percept induced by difference-stereogram. A two-way mapping between a surface and its difference surface is derived, proving that the difference-stereogram is the autostereogram of the difference surface. It is also proved and demonstrated that a difference-stereogram placed beside its basic pattern is forming a stereopair that shows the original surface.
Constructive Quasi-Ramsey Numbers and Tournament Ranking
Authors: A. Czygrinow, S. Poljak, V. Rödl
Venue: SIAM Journal on Discrete Mathematics (1999)

A constructive lower bound on the quasi-Ramsey numbers and the tournament ranking function was obtained in [S. Poljak, V. Rödl, and J. Spencer, SIAM J. Discrete Math., (1) 1988, pp. 372--376]. We consider the weighted versions of both problems. Our method yields a polynomial time heuristic with guaranteed lower bound for the linear ordering problem.
The Implementation of a VHDL-AMS to SPICE Converter
Authors: Shenggao Li, Brian Okoon, Mona Hella, Mohammed Ismail, Maya Rubeiz
Venue: Analog Integrated Circuits and Signal Processing (1999)

The implementation of a VHDL-AMS to SPICE converter (Vhdl2Spice) to be inserted in a complete CAD environment [1] is described. Vhdl2Spice generates a SPICE netlist by tracing down the VHDL IIR parse tree available from the already existing VHDL analyzer. Corresponding to each VHDL design unit, the output of the converter is represented as a subcircuit in SPICE. By doing so, the hierarchical characteristic of VHDL is retained in the SPICE representation&semi; hence future extension to both programs can be made in parallel. The Vhdl2Spice converter is also a demonstration of the extensibility of the AIRE [2] for a complete integration of VHDL-AMS with other CAD tools.
Weak Sharp Minima: Characterizations and Sufficient Conditions
Authors: Marcin Studniarski, Doug E. Ward
Venue: SIAM Journal on Control and Optimization (1999)

The problem of identifying weak sharp minima of order m, an important class of (possibly) nonisolated minima, is investigated in this paper. Some sufficient conditions for weak sharp minimality in nonsmooth mathematical programming are presented, and some characterizations of weak sharp minimality are obtained, with special attention given to orders one and two. It is also demonstrated that two of these sufficient conditions guarantee exactness of an l1 penalty function. A key role in this paper is played by two geometric concepts: the limiting proximal normal cone and a generalization of the contingent cone.
Coarsening Strategies for Unstructured Multigrid Techniques with Application to Anisotropic Problems
Authors: E. Morano, D. J. Mavriplis, V. Venkatakrishnan
Venue: SIAM Journal on Scientific Computing (1998)

Over the years, multigrid has been demonstrated as an efficient technique for solving inviscid flow problems. However, for viscous flows, convergence rates often degrade. This is generally due to the required use of stretched meshes (i.e., the aspect ratio AR = \Delta y / \Delta x
Some Topological Properties of Surfaces in Z3
Authors: Gilles Bertrand, Rémy Malgouyres
Venue: Journal of Mathematical Imaging and Vision (1999)

A basic property of a simple closed surface is the Jordan property: the complement of the surface has two connected components. We call back-component any such component, and the union of a back-component and the surface is called the closure of this back-component. We introduce the notion of strong surface as a surface which satisfies a strong homotopy property: the closure of a back-component is strongly homotopic to that back-component. This means that we can homotopically remove any subset of a strong surface from the closure of a back-component. On the basis of some results on homotopy, and strong homotopy, we have proved that the simple closed 26-surfaces defined by Morgenthaler and Rosenfeld, and the simple closed 18-surfaces defined by one of the authors are both strong surfaces. Thus, strong surfaces appear as an interesting generalization of these two notions of a surface.
Improving parallel system performance by changing the arrangement of the network links
Authors: V. Puente, C. Izu, J. A. Gregorio, R. Beivide, J. M. Prellezo, F. Vallejo
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

The Midimew network is an excellent contender for implementing the communication subsystem of a high performance computer. This network is an optimal 2D topology in the sense there are no other symmetric direct networks of degree 4 with a lower average distance or diameter. In fact, it reduces the diameter of the well known torus network by approximately &square;2. Although the topology was proposed and analyzed a decade ago, the lack of simple deadlock avoidance mechanisms prevented its utilization up to date. This study solved this drawback by applying the Bubble switching mechanism, a low cost deadlock-avoidance strategy developed by the authors. Moreover, by using routing tables we can configure our Virtual Cut-Through adaptive router to implement either a torus or a Midimew network. Thus, we can exploit the topological advantages of Midimew networks by simply changing the disposition of the wrap-around connections of its torus counterpart, without increasing the network implementation cost. To prove this assertion, we have carried out a thorough evaluation, from the hardware cost of the router to the parallel system performance under real loads.
Decomposition of relational schemata into components defined by both projection and restriction
Authors: Stephen J. Hegner
Venue: Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1988)

A generalized approach to the decomposition of relational schemata is developed in which the component views may be defined using both restriction and projection operators, thus admitting both horizontal and vertical decompositions. The realization of restrictions is enabled through the use of a Boolean algebra of types, while true independence of projections is modelled by permitting null values in the base schema. The flavor of the approach is algebraic, with the collection of all candidate views of a decomposition modelled within a lattice-like framework, and the actual decompositions arising as Boolean subalgebrac. Central to the framework is the notion of sidimensional join dependency, which generalizes the classical notion of join dependency by allowing the components of the join to be selected horizontally as well as vertically. Several properties of such dependencies are presented, including a generalization of many of the classical results known to be equivalent to schema acyclicity. Finally, a characterization of the nature of dependencies which participate in decompositions is presented. It is shown that there are two major types, the bidimensional join dependencies, which are tuple generating and allow tuple removal by implicit encoding of knowledge, and splitting dependencies, which simply partition the database into two components.
Efficient concurrency control for broadcast environments
Authors: Jayavel Shanmugasundaram, Arvind Nithrakashyap, Rajendran Sivasankaran, Krithi Ramamritham
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

A crucial consideration in environments where data is broadcast to clients is the low bandwidth available for clients to communicate with servers. Advanced applications in such environments do need to read data that is mutually consistent as well as current. However, given the asymmetric communication capabilities and the needs of clients in mobile environments, traditional serializability-based approaches are too restrictive, unnecessary, and impractical. We thus propose the use of a weaker correctness criterion called update consistency and outline mechanisms based on this criterion that ensure (1) the mutual consistency of data maintained by the server and read by clients, and (2) the currency of data read by clients. Using these mechanisms, clients can obtain data that is current and mutually consistent &ldquo;off the air&rdquo;, i.e., without contacting the server to, say, obtain locks. Experimental results show a substantial reduction in response times as compared to existing (serializability-based) approaches. A further attractive feature of the approach is that if caching is possible at a client, weaker forms of currency can be obtained while still satisfying the mutual consistency of data.
A case study of synthesis for industrial-scale analog IP: redesign of the equalizer/filter frontend for an ADSL CODEC
Authors: Rodney Phelps, Michael J. Krasnicki, Rob A. Rutenbar, L. Richard Carley, James R. Hellums
Venue: Proceedings of the 37th Annual Design Automation Conference (2000)

A persistent criticism of analog synthesis techniques is that they cannot cope with the complexity of realistic industrial designs, especially system-level designs. We show how recent advances in simulation-based synthesis can be augmented, via appropriate macromodeling, to attack complex analog blocks. To support this claim, we resynthesize from scratch, in several different styles, a complex equalizer/filter block from the frontend of a commercial ADSL CODEC, and verify by full simulation that it matches its original design specifications. As a result, we argue that synthesis has significant potential in both custom and analog IP reuse scenarios.
Using Bayesian networks to analyze expression data
Authors: Nir Friedman, Michal Linial, Iftach Nachman, Dana Pe'er
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

DNA hybridization arrays simultaneously measure the expression level for thousands of genes. These measurements provide a &ldquo;snapshot&rdquo; of transcription levels within the cell. A major challenge in computational biology is to uncover, from such measurements, gene/protein interactions and key biological features of cellular systems. In this paper, we propose a new framework for discovering interactions between genes based on multiple expression measurements This framework builds on the use of Bayesian networks for representing statistical dependencies. A Bayesian network is a graph-based model of joint multi-variate probability distributions that captures properties of conditional independence between variables. Such models are attractive for their ability to describe complex stochastic processes, and for providing clear methodologies for learning from (noisy) observations. We start by showing how Bayesian networks can describe interactions between genes. We then present an efficient algorithm capable of learning such networks and statistical method to assess our confidence in their features. Finally, we apply this method to the S. cerevisiae cell-cycle measurements of Spellman et al. [35] to uncover biological features
Application of XML tools for enterprise-wide RBAC implementation tasks
Authors: Ramaswamy Chandramouli
Venue: Proceedings of the fifth ACM workshop on Role-based access control (2000)

The use of Extensible Markup Language (XML) and its associated APIs, for information modeling and information interchange applications is being actively explored by the reseach community. In this paper we develop an XML Document Type Definition (DTD) for representing the schema of a Role-based Access Control (RBAC) Model and a conforming XML document containing the actual RBAC-based access control data for a commercial banking application. Based on this DTD, the XML document and the methods in the Document Object Model (DOM) API Level 1.0 standards, we describe three application tasks related to enterprise-wide implementation of RBAC. They are: (a)implementing an RBAC model for a database application (b)implementing RBAC models with identical data on two different database servers and (c)transforming data under an RBAC model to a different, but structurally similar model like Group-based Access Control model. Other potential Access Control Service applications exploiting the capabilities of some commercial XML processors are also outlined.
Linear Time Algorithms for Dominating Pairs in Asteroidal Triple-free Graphs
Authors: Derek G. Corneil, Stephan Olariu, Lorna Stewart
Venue: SIAM Journal on Computing (1999)

An independent set of three vertices is called an asteroidal triple if between each pair in the triple there exists a path that avoids the neighborhood of the third. A graph is asteroidal triple-free (AT-free) if it contains no asteroidal triple. The motivation for this investigation is provided, in part, by the fact that AT-free graphs offer a common generalization of interval, permutation, trapezoid, and cocomparability graphs.Previously, the authors have given an existential proof of the fact that every connected AT-free graph contains a dominating pair, that is, a pair of vertices such that every path joining them is a dominating set in the graph. The main contribution of this paper is a constructive proof of the existence of dominating pairs in connected AT-free graphs. The resulting simple algorithm, based on the well-known lexicographic breadth-first search, can be implemented to run in time linear in the size of the input, whereas the best algorithm previously known for this problem has complexity O(|V|3) for input graph G=(V,E). In addition, we indicate how our algorithm can be extended to find, in time linear in the size of the input, all dominating pairs in a connected AT-free graph with diameter greater than 3. A remarkable feature of the extended algorithm is that, even though there may be O(|V|2) dominating pairs, the algorithm can compute and represent them in linear time.
Enabling technologies for role based online decision engines
Authors: Thomas Gebhardt, Thomas Hildmann
Venue: Proceedings of the fifth ACM workshop on Role-based access control (2000)

The implementation of an RBAC system at the TUB led us towards a specific meaning of role-based access control, where decisions regarding user permissions are based on online evaluations of a distributed RBAC model, we call this approach role-based online decision (RoBOD). Requirements of our project partners and the integration of our solution into application environments showed that a number of enabling technologies, i.e. authentication and secure communication, are necessary to employ RBAC in networked application architectures.
Anchored conversations: chatting in the context of a document
Authors: Elizabeth F. Churchill, Jonathan Trevor, Sara Bly, Les Nelson, Davor Cubranic
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

This paper describes an application-independent tool called Anchored Conversations that brings together text-based conversations and documents. The design of Anchored Conversations is based on our observations of the use of documents and text chats in collaborative settings. We observed that chat spaces support work conversations, but they do not allow the close integration of conversations with work documents that can be seen when people are working together face-to-face. Anchored Conversations directly addresses this problem by allowing text chats to be anchored into documents. Anchored Conversations also facilitates document sharing; accepting an invitation to an anchored conversation results in the document being automatically uploaded. In addition, Anchored Conversations provides support for review, catch-up and asynchronous communications through a database. In this paper we describe motivating fieldwork, the design of Anchored Conversations, a scenario of use, and some preliminary results from a user study.
Hollywood: a business model for the future?
Authors: Charles E. Grantham
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

This paper elucidates an emergent theory of organizational structure, process and leadership which the author believes will characterize the Internet based workplace of the future. The theory was developed during a study of rapidly growing enterprises in the new media industry sponsored by CommerceNet in Los Angeles during 1998-99. Following an outline of this organizational model, the paper reports an in-depth case study of a on-going successful business concern which has been built upon the principles of this &ldquo;Hollywood&rdquo; model of information technology enabled firms and whose leadership espouses the role of `producer'. The paper concludes with a brief discussion of how this new organizational model can be implemented and how work process can be shifted from a task oriented project base to a community team basis for new ecommerce organizations.
A retro/prospective on APL Graphpak
Authors: Walt Niehoff
Venue: ACM SIGAPL APL Quote Quad (1998)

This paper suggests two general directions that one could take to modernize APL2 Graphpak and revitalize its evolution. One direction springboards off lessons learned during Graphpak's first decade and from some thinking that evolved during early (c. 1980) experiments with general arrays. The second direction exploits general arrays and APL2 functionality at a user-level. Some experiments are reported relating to both areas
MINRES and MINERR Are Better than SYMMLQ in Eigenpair Computations
Authors: Franciszek A. Dul
Venue: SIAM Journal on Scientific Computing (1998)

The SYMMLQ and MINRES methods for solving sparse, indefinite, symmetric systems of equations [SIAM J. Numer. Anal., 12 (1975), pp. 617--629] can be used inside the inverse or Rayleigh quotient iterations for computing the eigenpairs of large, sparse, generalized eigenproblems $A y = \lambda B y$. It is shown in this paper that the common opinion concerning the superiority of SYMMLQ over MINRES is not true in this context. Several results taken from quantum chemistry, acoustics, and structural mechanics are presented that show the superiority of MINRES and the new MINERR method over SYMMLQ, especially for ill-conditioned eigenproblems, where SYMMLQ may even diverge. Theoretical explanations of the observed phenomena are given. The use of MINRES or MINERR instead of SYMMLQ may thus lead to a significant increase in efficiency in large scale eigenvalue computations.
The Self-Organizing Map of Trees
Authors: Markus Peura
Venue: Neural Processing Letters (1998)

In the standard version of the Self-Organizing Map, each neuron is associated with a vector. An extension using trees instead of vectors is presented. Compared to vectors, trees provide remarkably more degrees of freedom. The essential points of self-organization, the distance function and the learning rule, are adapted to trees by means of graph matching. In order to avoid exhaustive searching in tree matching an efficient heuristic is introduced. The results of the experiments are promising: the proposed methods apply elegantly in the process of self-organization.
An object-oriented approach to educational software in building physics
Authors: Georg Reichard
Venue: ACM SIGAPL APL Quote Quad (1998)

An object-oriented building-physics software A.T.O.N. (which is the acronym for the German "General Thermal and Ecological Verifications") is described as an example for educational software written in APL. The software was developed at the Department for Structural Analysis at the Technical University of Graz, and has been successfully used for teaching building-physics. A.T.O.N. was designed in only four months. It comes with an user-friendly interface, which is easy and effortless to learn. Every manipulation of data is immediately monitored in graphical windows. In order to achieve this "question amp; answer"-concept a hybrid system was set up. This system consists of quick C- and Fortran-DLLs combined with the dyalogAPL trade; interpreter using CausewayPro trade; as an interactive development environment.
Non-isomorphic 3D rotational techniques
Authors: Ivan Poupyrev, Suzanne Weghorst, Sidney Fels
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

This paper demonstrates how non-isomorphic rotational mappings and interaction techniques can be designed and used to build effective spatial 3D user interfaces. In this paper, we develop a mathematical framework allowing us to design non-isomorphic 3D rotational mappings and techniques, investigate their usability properties, and evaluate their user performance characteristics. The results suggest that non-isomorphic rotational mappings can be an effective tool in building high-quality manipulation dialogs in 3D interfaces, allowing our subjects to accomplish experimental tasks 13% faster without a statistically detectable loss in accuracy. The current paper will help interface designers to use non-isomorphic rotational mappings effectively.
OOPM/RT: a multimodeling methodology for real-time simulation
Authors: Kangsun Lee, Paul A. Fishwick
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1999)

When we build a model of real-time systems, we need ways of representing the knowledge about the system and also time requirements for simulating the model. Considering these different needs, our question is &ldquo;How can we determine the optimal model that simulates the system by a given deadline while still producing valid outputs at an acceptable level of detail?&rdquo; We have designed OOPM/RT (Object-Oriented Physical Modeler for Real-Time Simulation) methodology. The OOPM/RT framework has three phases: (1) Generation of multimodels in OOPM using both structural and behavioral abstraction techniques, (2) Generation of AT (Abstraction Tree) which organizes the multimodels based on the abstraction relationship to facilitate the optimal model selection process, and (3) Selection of the optimal model that guarantees the deliver simulation results by the given amount of time. A more-detailed model (low abstraction model) is selected when we have enough time to simulate, while a less-detailed model (high abstraction model) is selected when the deadline is immediate. The basic idea of selection is to trade structural information for a faster runtime while minimizing the loss of behavioral information. We propose two possible approaches for the selection: an integer-programming-based approach and a search-based approach. By systematically handling simulation deadlines while minimizing the modeler's interventions, OOPM/RT provides an efficient modeling environment for real-time systems.
Integrated constraints and inheritance in DTAC
Authors: Jonathon E. Tidswell, Trent Jaeger
Venue: Proceedings of the fifth ACM workshop on Role-based access control (2000)

Inheritance and constraints are two common techniques for safely managing the complexity of large access control configurations. Inheritance is used to help factor the model, while constraints are used to help ensure that the complexity will not result in an unsafe configuration arising in the future evolution of the system. In this paper we develop an integrated mathematical approach to defining both inheritance and constraints in the dynamically typed access control (DTAC) model. In the process we identify several useful relationships among DTAC objects. The combination of DTAC and our new relationships allow us to graphically construct a greater variety and complexity of efficiently verifiable separation of duty constraints than any other model we are aware of.