ppxscal/embedding_network huggingface dataset:
Advanced Signal Processing for Wireless Multimedia Communications
Authors: Xiaodong Wang, Anders Host-Madsen
Venue: Proceedings of the The International Conference on Information Technology: Coding and Computing (ITCC'00) (2000)

We present some key advanced signal processing methodologies that have been developed in recent years for interference suppression in wireless networks. We will focus primarily on the problem of jointly suppressing multiple-access interference (MAI) and inter-symbol interference (ISI), which are the limiting sources of interference for the high data-rate wireless systems being proposed for many emerging application areas, such as wireless multimedia.We first present a signal subspace approach to blind joint suppression of MA1 and ISI. We then discuss a powerful iterative technique for joint interference suppression and decoding, so-called turbo multiuser detection that is especially useful for wireless multimedia packet communications. We also discuss space-time processing methods, which employ multiple antennas for interference rejection and signal enhancement. Finally, we touch briefly on the problems of suppressing narrowband interference and impulsive ambient noise, two other sources of radio-frequency interference present in wireless multimedia networks.
An Approach to Measuring and Assessing Dependability for Critical Software Systems
Authors: Dong Tang, Herbert Hecht
Venue: Proceedings of the Eighth International Symposium on Software Reliability Engineering (1997)

Traditional software testing methods combined with probabilistic models cannot measure and assess dependability for software that requires very high reliability (failure rate 0.999999). This paper proposes a novel approach, drawing on findings and methods that have been described individually but have never been combined, applied in the late testing phase or early operational phase, to quantify dependability for a category of critical software with such high requirements. The concepts that are integrated are: operational profile, rare conditions, importance sampling, stress testing, and measurement-based dependability evaluation. In the approach, importance sampling is applied on the operational profile to guide the testing of critical operations of the software, thereby accelerating the occurrence of rare conditions which have been shown to be a leading cause of failure in critical systems. The failure rates measured in the testing are then transformed to those that would occur in the normal operation by the likelihood ratio function of the importance sampling theory, and finally dependability for the tested software system is evaluated by using measurement-based dependability modeling techniques. When the acceleration factor is large (over 100), which is typical for a category of software of interest, it is possible to quantify a very high reliability or availability in a reasonable test duration. Some feasible methods to implement the approach are discussed based on real data.
New directions in traffic measurement and accounting: Focusing on the elephants, ignoring the mice
Authors: Cristian Estan, George Varghese
Venue: ACM Transactions on Computer Systems (TOCS) (2003)

Accurate network traffic measurement is required for accounting, bandwidth provisioning and detecting DoS attacks. These applications see the traffic as a collection of flows they need to measure. As link speeds and the number of flows increase, keeping a counter for each flow is too expensive (using SRAM) or slow (using DRAM). The current state-of-the-art methods (Cisco's sampled NetFlow), which count periodically sampled packets are slow, inaccurate and resource-intensive. Previous work showed that at different granularities a small number of "heavy hitters" accounts for a large share of traffic. Our paper introduces a paradigm shift by concentrating the measurement process on large flows only---those above some threshold such as 0.1&percnt; of the link capacity.We propose two novel and scalable algorithms for identifying the large flows: sample and hold and multistage filters, which take a constant number of memory references per packet and use a small amount of memory. If M is the available memory, we show analytically that the errors of our new algorithms are proportional to 1/M; by contrast, the error of an algorithm based on classical sampling is proportional to 1/&sqrt;M, thus providing much less accuracy for the same amount of memory. We also describe optimizations such as early removal and conservative update that further improve the accuracy of our algorithms, as measured on real traffic traces, by an order of magnitude. Our schemes allow a new form of accounting called threshold accounting in which only flows above a threshold are charged by usage while the rest are charged a fixed fee. Threshold accounting generalizes usage-based and duration based pricing.
Scheduling tasks with precedence constraints to solicit desirable bid combinations
Authors: Alexander Babanov, John Collins, Maria Gini
Venue: Proceedings of the second international joint conference on Autonomous agents and multiagent systems (2003)

In our previous research we suggested an approach to maximizing agents preferences over schedules of multiple tasks with temporal and precedence constraints. The proposed approach is based on Expected Utility Theory. In this paper we address two mutually dependent questions: (a) what are the properties of the problem domain that can facilitate efficient maximization algorithms, and (b) what criteria determine attractiveness of one or another potential solution to the agent. We discuss different ways of exploring the problem domain. We show that naive optimization approaches often fail to find solutions for risk-averse agents and propose ways of using properties of the domain to improve upon naive approaches.
Longest Common Consecutive Substring in Two Random Strings
Authors: Sarmad Abbasi
Venue:  (1997)

Let $\Sigma$ be a finite alphabet with $C$ letters. For any two strings $x$ and $y$ of length $n$, we let $S(x,y)$ denote the size of the longest common consecutive substring between $x$ and $y$; that is, $S(x,y)$ is the largest $k$ such that, $$ x_i \cdots x_{i+k} = y_j \cdots y_{j+k}$$ for some $i$ and $j$. We show that for $x$ and $y$ chosen uniformly among all possible strings of length $n$, $S(x,y)$ is highly concentrated around $2 \log_C n$. More precisely, for any $a \geq 1$ $$ \Pr [ |S(x,y) - 2 \log_C n | < a] \leq {18 C^{-a} \over n^2}.$$ This enables us to show that the expected value of $S(x,y)$ is with a constant additive factor of $2 \log n$.
Cycles in Back Circulant Latin Squares
Authors: Joan Cooper, Diane Donovan, D. J. Nott
Venue:  (1992)

Minimal critical sets for back circulant latin squares, of even order, have been determined. However the size of the minimal critical set for a back circulant latin square of odd order, has not been determined. It is known that any minimal critical set in a back circulant latin square of odd order must contain fewer than (n 2 - 1 )/4 elements. It seems clear that in order to identify a minimal critical set in a back circulant latin square of odd order, it will be necessary to find all cycles of minimal length within the latin square and then establish the minimum number of elements needed to cover these cycles. In this paper we document the existence of a number of different cycles in a back circulant latin square of odd order.
Bubbleworld: a new visual information retrieval technique
Authors: Christopher Van Berendonck, Timothy Jacobs
Venue: Proceedings of the Asia-Pacific symposium on Information visualisation - Volume 24 (2003)

Visualisation has significant advantages over traditional textual lists for improving cognition in information retrieval. To realise these advantages, we identify a set of cognitive principles and usage patterns for information retrieval. We apply these principles and patterns to the design of a prototype visual information retrieval system, Bubbleworld. In Bubbleworld, we apply a variety of visual techniques that successfully transform the internal mental representations of the information retrieval problem to an efficient external view and, through visual cues, provide cognitive amplification at key stages of the information retrieval process. We enhance the knowledge acquisition process by providing query refinement and interaction techniques that facilitate the specification of complex search schemas and integrate these with the mechanisms to incorporate predefined ontological models. We then attempt to validate the new visual techniques through empirical user trials to gain a better understanding of its benefits.
A neocognitron synthesized by production rule for handwritten character recognition
Authors: D. S. Yeung, Hing-Yip Chan, Yau Chong Lau
Venue: Proceedings of the First International Symposium on Intelligence in Neural and Biological Systems (INBS'95) (1995)

The objective of this paper is to propose a modified neocognitron with production rules embedded for handwritten character recognition. Structured information about the basic features in a character is stored in the production rules constructed by users. A mapping scheme is used to map these rules into the connection weights of the neocognitron. The ability to represent structured information for characters using production rules provides some insights into how this structured information or knowledge can be processed by the network for its character recognition or refinement in the case where a character is misrecognized. The whole process can be controlled by users by analyzing the results of the recognition by refining the production rules to improve the recognition rate. It is much more flexible, and can be used as tools to build a rapid prototype of a pattern recognizer with fault diagnosis capability.
Efficient Parallel Algorithms Can Be Made Robust
Authors: Paris C. Kanellakis, Alex A. Shvartsman
Venue:  (1989)

The efficient parallel algorithms proposed for many fundamental problems, such as list ranking, computing preorder numberings on trees and integer sorting, are very sensitive to processor failures. The requirements of efficiency (commonly formalized using {\em Parallel-time x Processors} as a cost measure) has led to the design of highly tuned PRAM algorithms which, given the additional constraint of simple processor failures, unfortunately become inefficient or even incorrect. We propose a new notion of {\em robustness} that combines efficiency with fault tolerance. For the common case of fail-stop errors, we develop a general and easy-to-implement technique to make robust many efficient parallel algorithms, e.g., algorithms for all the problems listed above. More specifically,{\em for any dynamic pattern of fail-stop errors on} a CRCW PRAM {\em with at least one surviving processor}, our method increases the original algorithm''s cost by at most a {\em polylog} multiplicative factor. We also show that at least a {\em log/loglog} multiplicative overhead will be incurred for certain patterns of failures by any algorithm that implements robust solutions to the problems listed.
Sensitivity of reliability growth models to operational profile errors
Authors: A. N. Crespo, P. Matrella, A. Pasquini
Venue: Proceedings of the The Seventh International Symposium on Software Reliability Engineering (1996)

The estimation of the operational profile is one of the key factors during the use of software reliability growth models. However, the operational profile can be very difficult to estimate in particular applications such as software used for process control. In other cases, a single operational profile may not be sufficient to describe the use of the product by a number of different customers. An operational profile may also change during the development of software or during its operational usage. All these cases may lead to errors in the estimation of the operational profile. The paper describes an empirical evaluation of the sensitivity of reliability growth models to errors in the estimation of the operational profiles. Some reliability growth models are applied during the testing phase of a software system. The particular characteristics of the case study allow the measurement of the actual reliability growth of the software and its comparison with the estimations provided by the models. Measurement and comparison are repeated for different operational profiles giving information about the effect of a possible error in the estimation of the operational profile. Results show that errors in the operational profile estimation do not heavily affect reliability estimates and that their influence is strongly dependent on the accuracy with which the software system has been tested.
Tautomerism as a constraint on the composition of alternative nucleotide alphabets
Authors: D. A. Mac Dónaill
Venue: Proceedings of the eighth international conference on Artificial life (2002)

The factors determining the composition of the nucleotide alphabet are not self-evident. While, straightforward extensions to the alphabet such as iC:iG have received some theoretical attention, more exotic nucleotide pairs, such as α:Γ, β:δ, and κ:X, have been ignored. At the current state of knowledge the possibility of viable alternative nucleotide alphabets remains an intriguing possibility. In this paper the broader space of potential letters is considered in terms of hydrogen donor-acceptor patterns. Quantum chemical simulations at the PM3 semi-empirical level of approximation are employed to examine the stability of different tautomeric forms of candidate letters. The results suggest that tautomeric instability favoring hydroxyl elements over keto groups is one of the critical constraints on viable alternative alphabets. Rotation of a hydroxyl group changes the expressed hydrogen donor/acceptor pattern, destroying the integrity of the principal recognition feature. Two distinct alphabets appear viable, one containing the familiar aA:T/U and C:G, and a second containing just κ:X. Thus tautomerism offers an explanation for the composition of the natural alphabet, while posing challenges for the engineering of alternative alphabets.
Topic distillation using hierarchy concept tree
Authors: Ikkyu Choi, Minkoo Kim
Venue: Proceedings of the 26th annual international ACM SIGIR conference on Research and development in informaion retrieval (2003)

In this paper, we propose a new approach for topic distillation on World Wide Web. Topic distillation is to find quality documents related to the user query topic. Our approach is based on Bharat's topic distillation algorithm [1]. We present the analysis of hyperlink graph structure using hierarchy concept tree to solve the mixed hubs problem that is also remained in the Bharat's algorithm. For assigning better weights to hyperlinks which point to relevant documents among hyperlinks in a document, we try to find the relationship in documents connected by hyperlinks using content analysis and we assign weights to hyperlinks based on the relationship. We evaluated this algorithm using 50 topics on WT10g corpus and obtained improved results.
The Pairwise Intersection Problem for Monotone Polygons
Authors: David B. Levine
Venue:  (1986)

Geometric intersection problems arise in a number of areas of computer science including graphics and VLSI design rule checking. Previous work has concentrated on solving the pairwise intersection problem for line segments and iso-oriented rectangles. This thesis extends that work by presenting efficient algorithms to solve the pairwise intersection problem for monotone polygons. For general segments, the problem has been solved in O(N+I)*logN) time using a sweeping line technique, where N is the number of segments and I is the number of intersections reported. We combine this technique with approaches taken to solve the iso-oriented rectangle problem to yield an algorithm which solves the pairwise intersection problem for monotone polygons in the same asymptotic time. In addition, there are certain classes of line segments for which the pairwise intersection problem may be solved in O(N*logN + I) time, the best possible. We generalize each such class of line segments to a class of polygons and present algorithms to solve the associated polygon problem. Finally, we discuss the impacts which possible improvements to the line segment problem would have on our results. 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
Short--term recurrences for indefinite preconditioning of saddle point problems
Authors: M. Rozloznik, V. Simoncini
Venue:  (2000)

We are interested in the numerical solution of large structured indefinite symmetric linear systems arising in mixed finite element approximations of the magnetostatic problem; in particular, we analyze definite block--diagonal and indefinite symmetric preconditioners. Relating the algebraic characteristics of the resulting preconditioned matrix to the properties of the continuous problem and of its finite element discretization, we show that the considered preconditioning strategies make the used Krylov subspace solver insensitive to the mesh refinement parameter, in terms of number of iterations. In order to achieve computational efficiency, we also analyze algebraic approximations to the optimal preconditioners, and discuss their performance on real two and three dimensional application problems.
Does Multicast Communication Make Sense in Write Invalidation Traffic?
Authors: Hung-Chang Hsiao, Chung-Ta King
Venue: Proceedings of the Seventh International Conference on Parallel and Distributed Systems (2000)

In distributed shared-memory (DSM) multiprocessors, a write operation requires multiple messages to invalidate the nodes, which share and cache the memory block to be written. The resultants write stall time is a performance hurdle to such systems. One approach to efficient invalidation is to use multicast messages to reach the sharing nodes. In this paper, we use application-driven simulation to evaluate two multicast-based invalidation schemes: dual-path [10] and pruning [11]. Based on our experimental settings, we found that multicasts improve invalidation traffic for four of the six evaluated real applications. The remaining two programs are computation intensive, and multicast-based invalidation is less effective. However, since they induce bursty communication, we found that multicasts help to relieve the network congestion during those periods. Dual-path performs a little better than pruning, because it is less sensitive to routing delay in the routers. We also found that cache size is an important design parameter for multicast-based invalidation. It is more effective for DSM multiprocessors with larger caches.
Automated Analysis of Fault-Tolerance in Distributed Systems
Authors: Scott D. Stoller, Fred B. Schneider
Venue:  (1996)

This paper describes a method for automated analysis of fault-tolerance properties of distributed systems. The framework is based on ideas from stream-processing semantics for networks of processes and abstract interpretation of programs. The stream-processing model provides modularity and a clean algorithmic basis for the analysis. For efficiency, all aspects of a system''s behavior can be approximated in the analysis, including: values (the data transmitted in messages), multiplicities (the number of times each value is sent), and orderings (the order in which values are sent). The approximation mechanisms are based on abstract interpretation, symbolic computation, and partial orders. Approximations are essential to support abstraction from aspects of a system''s behavior that do not directly impact its fault-tolerance. Another feature of our approach is that perturbations due to failures can be represented explicitly. This allows fault-tolerance requirements to be expressed as bounds on the acceptable perturbations to a system''s behavior as a consequence of certain failures. This facilitates separation of fault-tolerance from other correctness requirements and sometimes enables more efficient analysis. The analysis has been implemented in a prototype tool.
The Algorithmic Analysis of Hybrid Systems
Authors: Rajeev Alur, Costas Courcoubetis, Nicolas Halbwachs, Thomas A. Henzinger, Pei Ho, Xavier Nicollin, Alfredo Olivero, Joseph Sifakis, Sergio Yovine
Venue:  (1994)

We present a general framework for the formal specification and algorithmic analysis of hybrid systems. A hybrid system consists of a discrete program with an analog environment. We model hybrid systems as finite automata equipped with variables that evolve continuously with time according to dynamical laws. For verification purposes, we restrict ourselves to linear hybrid systems, where all variables follow piecewise-linear trajectories. We provide decidability and undecidability results for classes of linear hybrid systems, and we show that standard program-analysis techniques can be adapted to linear hybrid systems. In particular, we consider symbolic model-checking and minimization procedures that are based on the reachability analysis of an infinite state space. The procedures iteratively compute state sets that are definable as unions of convex polyhedra in multidimensional real space. We also present approximation techniques for dealing with systems for which the iterative procedures do not converge.
Modern Data Warehousing, Mining, and Visualization: Core Concepts
Authors: George M. Marakas
Venue:  (2002)

:Written from a multidisciplinary user/manager approachrather than a designer approach, this text looks at data warehousing technologies necessary to support the business processes of the twenty-first century. It explores the basic concepts of data mining, warehousing, and visualizationwith an emphasis on both technical and managerial issues and the implication of these modern emerging technologies on those issues. Includes mini-cases, narrative vignettes, and an abundance of graphics. Data mining and visualization exercisesusing an included fully-enabled, but time-limited version of Megaputer's PolyAnalyst and TextAnalyst data mining and visualization softwaregive readers hands-on experience with real-world applications. The Data Warehouse. Data Mining and Data Visualization. Data Mining Technologies. Executive Information Systems. Designing and Building the Data Warehouse. The Future of Data Mining, Warehousing, and Visualization.
Agent Chaining: An Approach to Dynamic Mobile Agent Planning
Authors: Jin-Wook Baek, Jae-Heung Yeo, Heon-Young Yeom
Venue: Proceedings of the 22 nd International Conference on Distributed Computing Systems (ICDCS'02) (2002)

Recently, the distributed agent concept has become a new computing paradigm in the Internet distributed computing, including the mobile computing. Mobile agent planning is one of the most important techniques for completing a given task efficiently. The static planning technique may not be the best approach in real network environments. This is mainly due to the fluctuation of network traffic, that is, connection failures or heavy traffic on the network. For better performance, it is necessary that mobile agents be more sensitive to the network conditions.In this paper, we propose a dynamic planning algorithm, named n-ary agent chaining, which is based on static mobile agent planning. Mobile agents can change their itinerary dynamically according to current network status using the proposed algorithm. The proposed algorithm also takes into account the locality of target nodes on the network. Thus, with a properly chosen locality factor, it can adapt to realistic network situations. Using an agent reproduction technique, the nodes, not processed by the original agent, obtain a second chance to be visited. Agents reproduced from the original one, named cloned agents, processthe unprocessed nodes in the proposed algorithm. Since the turn-around time can be calculated mathematically with known network statistics before launching the agents, the proposed algorithm is suitable for agent problem domains with deadline constraints.