ppxscal/embedding_network huggingface dataset:
On the Computational Complexity of Upward and Rectilinear Planarity Testing
Authors: Ashim Garg, Roberto Tamassia
Venue:  (1994)

A directed graph is said to be upward planar if it can be drawn in the plane such that every edge is a monotonically increasing curve in the vertical direction, and no two edges cross. An undirected graph is said to be rectilinear planar if it can be draw in the plane such that every edge is a horizontal or vertical segment, and no two edges cross. Testing upward planarity and rectilinear planarity are fundamental problems in the effective visualization of various graph and network structures. For example, upward planarity is useful for the display of order diagrams and subroutine-call graphs, while rectilinear planarity is useful for the display of circuit schematics and entity-relationship diagrams. In this paper we show that upward planarity testing and rectilinear planarity testing are NP-complete problems. We also show that it is NP-hard to approximate the minimum number of bends in a planar orthogonal drawing of an $n$-vertex graph with an $O(n^{1-\epsilon})$ error, for any $\epsilon < 0$.
A Direct Algorithm for Type Inference in the Rank 2 Fragment of the Second-Order Lambda-Calculus
Authors: Joe Wells
Venue:  (1993)

Abstract We study the problem of type inference for a family of polymorphic type disciplines containing the power of Core-ML. This family comprises all levels of the stratification of the second-order lambda-calculus by ``rank'''' of types. We show that typability is an undecidable problem at every rank k <= 3 of this stratification. While it was already known that typability is decidable at rank >= 2, no direct and easy-to-implement algorithm was available. To design such an algorithm, we develop a new notion of reduction and show how to use it to reduce the problem of typability at rank 2 to the problem of acyclic semi-unification. A by-product of our analysis is the publication of a simple solution procedure for acyclic semi-unification.
A Parallel Graph Partitioning Algorithm for a Message-Passing Multiprocessor
Authors: John R. Gilbert, Earl Zmijewski
Venue:  (1987)

We develop a parallel algorithm for partitioning the vertices of a graph into $p \geq 2$ sets in such a way that few edges connect vertices in different sets. The algorithm is intended for a message-passing multiprocessor system, such as the hypercube, and is based on the Kernighan-Lin algorithm for finding small edge separators on a single processor. We use this parallel partitioning algorithm to find orderings for factoring large sparse symettric positive definite matrices. These orderings not only reduce fill, but also result in good processor utilization and low communication overhead during the factorization. We provide a complexity analysis of the algorithm, as well as some numerical results from an Intel hypercube and a hypercube simulator.
The Hierarchical Daisy Architecture for Causal Delivery
Authors: Roberto Baldoni, Roy Friedman, Robbert van Renesse
Venue:  (1996)

In this paper, we propose the {\em hierarchical daisy architecture}\/, which provides causal delivery of messages sent to any subset of processes. The architecture provides fault tolerance and maintains the amount of control information within a reasonable size. It divides processes into {\em logical}\/ groups. Messages inside a logical group are sent directly, while messages that need to cross logical groups'' bounderies are forwarded by servers. We proof the correctness of the daisy architecture and discuss possible optimizations.
A new graphic user interface to the South Pole information system
Authors: Stefania Biagioni, Carlo Carlesi, Ovidio Salvetti, Vincenzo Spoto
Venue:  (1997)

An integrated multi-disciplinary information system, known as the South Pole Information System (SPIS), has been developed within the framework of the Italian Programme for Research in the Antarctic promoted by ENEA (National Agency for Alternative Energy). The system consists of a series of heterogeneous data_banks sited in Local Centres, geographically distributed throughout the Italian territory, each one dedicated to a specific theme. The main objective of the South Pole System has been to make all the data and information concerning the Italian Antarctic expeditions available to the scientific community, through the creation of a series of specific networked Local Centres (LC). The system thus provides: i) local and remote access to all the information; ii) compatibility with international standards; iii) homogeneous user-friendly interfaces; iv) the possibility to perform comparative and interdisciplinary searches.
Probabilistic Simulation-Based Analysis of Complex Real-Time Systems
Authors: Anders Wall, Johan Andersson, Christer Norström
Venue: Proceedings of the Sixth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (2003)

Many industrial real-time systems have evolved over a long period of time and were initially so simple that it was possible to predict consequences of adding new functionality by common sense. However, as the system evolves the possibility to predict the consequences of changes becomes more and more difficult unless models and analysis method can be used. Moreover, traditional real-time models, e.g., fixed priority analysis, may be too simple for accurately capturing a complex system's characteristics. For instance, assuming worst-case execution time may not be realistic. Hence, analyses based on these models may give an overly pessimistic result.In this paper we describe our approach to introducing analyzability into complex real-time control systems. The proposed method is based on analytical models and discrete-event based simulation of the system behavior based on these models. The models describe execution times as statistical distributions which are measured and calculated in the existing system. Simulation will not only enable models with statistical execution times, but also correctness criterion other than meeting deadlines, e.g., non-empty communication queues. The simulation result is analyzed by specifying properties in a probabilistic property language. The result of such an analysis is either of probabilistic nature or boolean depending on how the property is specified. Having accurate system models enable analysis of the impact on the temporal behavior of, e.g., customizing or maintaining the software.
A Comparative Study of Solar Interference on the Iridium and MSS Constellations
Authors: Tsangmin Chang
Venue:  (1993)

Radio frequency cross-links are the preferred communication medium for low earth orbit (LEO) satellite networks today. However, future cross-link designs may be expected to deploy laser cross-links to increase communication bandwidth. These cross-links are rendered inoperative when incident with high level background radiation sources such as the Sun. The Iridium and Multiple Satellite System (MSS) are two well researched constellations in the literature and are ideal candidates for the investigation of solar interference on point-to-point constellations. In both cases, the impact of solar radiation on link availability is the goal of this project. Evaluation of link availability based on the motions of the bodies in question is computationally infeasible. It is therefore necessary to reduce the state space to a manageable computing basis by reformulating the problem domain and by simulation. In this report the development of an algorithm and a software simulation tool to analyze the two constellations will be presented and the results of laser cross-link availability will be discussed. The technique introduced here may be generalized to study a variety of different constellations. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Scenario description for multi-agent simulation
Authors: Yohei Murakami, Toru Ishida, Tomoyuki Kawasoe, Reiko Hishiyama
Venue: Proceedings of the second international joint conference on Autonomous agents and multiagent systems (2003)

Making it easier to design interactions between agents and humans is essential for realizing multi-agent simulations of social phenomena such as group dynamics. To realize large-scale social simulations, we have developed the scenario description languages Q and IPC (Interaction Pattern Card); they enable experts in the application domain (often not computing professionals) to easily create complex scenarios. We have also established a four-step process for creating scenarios: 1) defining a vocabulary, 2) describing scenarios, 3) extracting interaction patterns, and 4) integrating real and virtual experiments. In order to validate the scenario description languages and the four-step process, we ran a series of evacuation simulations based on the proposed languages and process. We successfully double-check the result of the previous controlled experiment done in a real environment.
On-Chip Interconnect Inductance - Friend or Foe (Invited)
Authors: S. Simon Wong, Patrick Yue, Richard Chang, So-Young Kim, Bendik Kleveland, Frank O'Mahony
Venue: Proceedings of the 4th International Symposium on Quality Electronic Design (2003)

Inductance associated with on-chip wires can nolonger be ignored as chip operation frequenciesincrease into GHz regime. Because the magnetic fieldpropagates a very long range, the extraction of wireinductance is not just dependent on the immediateneighboring environment. This paper discusses thevarious difficulties of extracting inductance ofrandomly placed wires in a typical chip environment.With dedicated return path, the wire inductance can becontrolled and benefit the design of high-speedcircuits. Specific examples are illustrated.
On the uniform convergence of local time and the uniform consistency of density estimators for ergodic diffusions
Authors: J. H Zanten
Venue:  (1999)

We prove a theorem on the uniform convergence of the local time of an ergodic diffusion. This result is then used to investigate certain estimators of the invariant density of an ergodic diffusion, including kernel estimators. We show that the pointwise consistency of these estimators can be strengthened to uniform consistency.
Protein Secondary Structure Prediction Using Data Mining Tool C5
Authors: Meiliu Lu, Du Zhang, Hongjun Xu, Ken Tse-yau Lau, Li Lu
Venue: Proceedings of the 11th IEEE International Conference on Tools with Artificial Intelligence (1999)

This paper reports our experimental results in protein secondary structure prediction using a machine learning software C5. Accuracy improvement in prediction of protein secondary structures is the focus of our study. Starting with a target protein with unknown secondary structures, we investigate three different approaches and find that training cases selected based on sequence homology can achieve the highest predictive accuracy of 75% in test cases. Our result indicates that how to select proteins for the training cases has the most significant impact on predictive accuracy.
On some pel level research problems
Authors: M. Pitteway
Venue: Proceedings of the IEEE Conference on Information Visualisation (1997)

The note lists some unsolved research problems concerning line (or edge) drawing algorithms for raster displays which seem to be still outstanding in 1997. Work in progress includes the so called "pixel perfect" speeded up versions of Bresenham's (1965) line drawing algorithm designed to exploit the parallel capabilities of modern display processors. Where should the build up of multi-pixel segments be terminated for optimum performance? The representation of circles, conic sections and other curves, by short, straight line segments or "otherwise" by direct generation at the pixel level: what is the "best" chain code definition? Is it "better" to use four-way or eight-way connected outlines? Can one use "strength reduction" to improve the performance of the algorithms when implemented with modern parallel hardware? How can one best convert between the "real" (floating point) coordinates of a real world model and the integer working required at the pixel level? Finally, how can one best use grey scale when it is available to soften the jaggies which so often spoil the appearance of fount outlines and other objects?
Distributed Communication in ML
Authors: Mark Hayden
Venue:  (1997)

We present our experience in implementing a group communication toolkit in Objective Caml, a dialect of the ML family of programming languages. We compare the toolkit both quantitatively and qualitatively to a predecessor toolkit which was implemented in C. Our experience shows that using the high-level abstraction features of ML gives substantial advantages. Some of these features, such as automatic memory management and message marshalling, allowed us to concentrate on those pieces of the implementation which required careful attention in order to achieve good performance. We conclude with a set of suggested changes to both the ML language and the particular implementation we used.
Partial-Volume Bayesian Classification of Material Mixtures in MR Volume Data using Voxel Histograms
Authors: David H. Laidlaw, Kurt W. Fleischer, Alan H. Barr
Venue:  (1997)

We present a new algorithm for identifying the distribution of different material types in volumetric datasets such as those produced with Magnetic Resonance Imaging (MRI) or Computed Tomography (CT). Because we allow for mixtures of materials and treat voxels as regions, our technique reduces the classification artifacts that thresholding can create along boundaries between materials and is particularly useful for creating accurate geometric models and renderings from volume data. It also has the potential to make more-accurate volume measurements and classifies noisy, low-resolution data well. There are two unusual aspects to our approach. First, we assume that, due to partial-volume effects, voxels can contain more than one material, e.g., both muscle and fat; we compute the relative proportion of each material in the voxels. Second, we incorporate information from neighboring voxels into the classification process by reconstructing a continuous function, p(x), from the samples and then looking at the distribution of values that p takes on within the region of a voxel. This distribution of values is represented by a histogram taken over the region of the voxel; the mixture of materials that those values measure is identified within the voxel using a probabilistic Bayesian approach that matches the histogram by finding the mixture of materials within each voxel most likely to have created the histogram. The size of regions that we classify is chosen to match the spacing of the samples because the spacing is intrinsically related to the minimum feature size that the reconstructed continuous function can represent.
g-Elements of matroid complexes
Authors: Ed Swartz
Venue: Journal of Combinatorial Theory Series B (2003)

A g-element for a graded R-module is a one-form with properties similar to a Lefschetz class in the cohomology ring of a compact complex projective manifold, except that the induced multiplication maps are injections instead of bijections. We show that if k(Δ) is the face ring of the independence complex of a matroid and the characteristic of k is zero, then there is a nonempty Zariski open subset of pairs (Θ, Ω) such that Θ is a linear set of parameters for k(Δ) and Ω is a g-element for k(Δ)/ 〈Θ〉. This leads to an inequality on the first half of the h-vector of the complex similar to the g-theorem for simplicial polytopes.
Random sampling for the monomer-dimer model on a lattice
Authors: J. Berg, R. Brouwer
Venue:  (1999)

In the monomer-dimer model on a graph, each matching (collection of non-overlapping edges) ${M}$ has a probability proportional to $\lambda^{|M|}$, where $\lambda < 0$ is the model parameter, and $|M|$ denotes the number of edges in $M$. An approximate random sample from the monomer-dimer distribution can be obtained by running an appropriate Markov chain (each step of which involves an elementary local change in the configuration) sufficiently long. Jerrum and Sinclair have shown (roughly speaking) that for an arbitrary graph and fixed $\lambda$ and $\varepsilon$ (the maximal allowed variational distance from the desired distribution), $O(|\Lambda|^2 |E|)$ steps suffice, where $|E|$ is the number of edges and $|\Lambda|$ the number of vertices of the graph. For sufficiently nice subgraphs (e.g. cubes) of the $d$-dimensional cubic lattice we give an explicit recipe to generate approximate random samples in (asymptotically) siginificantly fewer steps, namely (for fixed $\lambda$ and $\varepsilon$) $O(|\Lambda| \, (\ln |\Lambda|)^2)$.
On the Use of Neural Networks in the Generalized Likelihood Ratio Test for Detecting Abrupt Changes in Signals
Authors: Craig L. Fancourt, Jose C. Principe
Venue: Proceedings of the IEEE-INNS-ENNS International Joint Conference on Neural Networks (IJCNN'00)-Volume 2 - Volume 2 (2000)

With the advent of efficient algorithms and fast computers for training neural networks, it is now feasible to employ neural network predictors in the generalized likelihood ratio (GLR) test for detecting abrupt non-stationary changes in the dynamics of a time series. We examine some of the special issues involved and present some simulation results validating the new hybrid algorithm.
Tight bounds on the competitive ratio on accommodating sequences for the seat reservation problem
Authors: E. Bach, J. Boyar, L. Epstein, L. M. Favrholdt, Tao Jiang, K. S. Larsen, Rob Stee, G. Lin
Venue:  (2000)

The unit price seat reservation problem is investigated. The seat reservation problem is the problem of assigning seat numbers on-line to requests for reservations in a train traveling through $k$ stations. We are considering the version where all tickets have the same price and where requests are treated fairly, i.e., a request which can be fulfilled must be granted. For fair deterministic algorithms, we provide an asymptotically matching upper bound to the existing lower bound which states that all fair algorithms for this problem are $\frac{1}{2}$-competitive on accommodating sequences, when there are at least three seats. Additionally, we give an asymptotic upper bound of $\frac{7}{9}$ for fair randomized algorithms against oblivious adversaries. We also examine concrete on-line algorithms, First-Fit and Random, for the special case of two seats. Tight analyses of their performance are given.
A Compact Built-In Current Sensor for IDDQ Testing
Authors: Y. Tsiatouhas, Th. Haniotakis, D. Nikolos
Venue: Proceedings of the 6th IEEE International On-Line Testing Workshop (IOLTW) (2000)

In this paper a simple to implement, compact, build-in current sensor for IDDQ testing of CMOS VLSI circuits based on current mirroring techniques is proposed. This sensor can attain small detection times and can be used for both on-line and off-line IDDQ testing.
A Development Environment for Horizontal Microcode
Authors: Alexander Aiken, Alexandru Nicolau
Venue:  (1986)

This paper describes a development environment for horizontal microcode. The environment used Percolation Scheduling a transformational system for parallelism extraction and an interactive profiling system that gives the user control over the microcode compaction process while reducing the burdensome details of architecture, correctness-preservation, and synchronization. Through a graphical interface the user suggests what can be executed in parallel, while the sytem performs the actual changes using semantics-preserving transformations. If a request cannot be satisfied, the system reports the problem causing the failure. The user may then help eliminate the problem by supplying guidance or information not explicit in the code. Index terms microcode, compaction, Percolation Scheduling, environment, transformation, parallelization, compiler.
A Framework for Interprocedural Locality Optimization Using Both Loop and Data Layout Transformations
Authors: Mahmut Kandemir, Alok Choudhary, J. Ramanujam, Prithviraj Banerjee
Venue: Proceedings of the 1999 International Conference on Parallel Processing (1999)

There has been much work recently on improving the locality performance of loop nests in scientific programs through the use of loop as well as data layout optimizations. However, little attention has been paid to the problem of optimizing locality in whole programs, particularly in the presence of procedures. Current techniques do not propagate layout optimizations across procedures boundaries; this is critical for realistic scientific codes, since the cost of explicitly transforming memory layouts across procedure boundaries might be very high. In this paper we present a locality optimization framework that uses both loop and data transformations to improve cache locality program-wide. Our framework propagates layout (or locality) constraints as a system of equalities across procedures and involves two traversals in the call graph representation of the program. Preliminary experimental results obtained on an R10000 based system demonstrate the power of the framework.
Classification and Lower Bounds for MEMS Arrays and Vibratory Parts Feeders: What Programmable Vector Fields Can (and Cannot) Do --Part I
Authors: Karl F. Bohringer, Bruce R. Donald, Noel C. MacDonald
Venue:  (1995)

Programmable vector fields can be used to control a variety of flexible planar parts feeders. These devices can exploit exotic actuation technologies such as arrayed, massively-parallel microfabricated motion pixels or transversely vibrating (macroscopic) plates. These new automation designs promise great flexibility, speed, and dexterity---we believe they may be employed to orient, singulate, sort, feed, and assemble parts. However, since they have only recently been invented, programming and controlling them for manipulation tasks is challenging. By chaining together sequences of vector fields, the equilibrium states of a part in the field may be cascaded to obtain a desired final state. The resulting strategies require no sensing and enjoy efficient planning algorithms. This paper begins by describing our experimental devices. In particular, we describe our progress in building the {\sc M-Chip} (\underline{m}anipulation \underline{chip}), a massively parallel array of programmable micro-motion pixels. As proof of concept, we demonstrate a prototype {\sc M-Chip} containing over 11,000 silicon actuators in one square inch. Both the {\sc M-Chip}, as well as macroscopic devices such as transversely vibrating plates, may be programmed with vector fields, and their behavior predicted and controlled using our {\em equilibrium analysis}. We demonstrate lower bounds (i.e., impossibility results) on what the devices {\em cannot} do, and results on a classification of control strategies yielding design criteria by which well-behaved manipulation strategies may be developed. We provide sufficient conditions for programmable fields to induce well-behaved equilibria on every part placed on our devices. We define {\em composition operators} to build complex strategies from simple ones, and show the resulting fields are also well-behaved. We discuss whether fields outside this class can be useful and free of pathology.