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631169
An Accurate Worst Case Timing Analysis for RISC Processors.
An accurate and safe estimation of a tasks worst case execution time (WCET) is crucial for reasoning about the timing properties of real-time systems. In RISC processors, the execution time of a program construct (e.g., a statement) is affected by various factors such as cache hits/misses and pipeline hazards, and thes...
INTRODUCTION In real-time computing systems, tasks have timing requirements (i.e., deadlines) that must be met for correct operation. Thus, it is of utmost importance to guarantee that tasks finish before their deadlines. Various scheduling techniques, both static and dynamic, have been proposed to ensure this guarante...
pipelined execution;cache memory;worst case execution time;real-time system;RISC processor
631174
Conversion of Units of Measurement.
Algorithms are presented for converting units of measurement from a given form to a desired form. The algorithms are fast, are able to convert any combination of units to any equivalent combination, and perform dimensional analysis to ensure that the conversion is legitimate. Algorithms are also presented for simplific...
Introduction Although many programming languages are described as "strongly typed", in most languages the types of numeric quantities are described only in terms of the numeric representation (real, integer, etc.) but not in terms of the units of measurement (meters, feet, etc.) of the quantity represented by a variabl...
dimensional analysis;unit of measurement;data type;unit conversion
631185
TLA in Pictures.
Predicate-action diagrams, which are similar to standard state-transition diagrams, are precisely defined as formulas of TLA (the Temporal Logic of Actions). We explain how these diagrams can be used to describe aspects of a specificationand those descriptions then proved correcteven when the complete specification can...
Introduction Pictures aid understanding. A simple flowchart is easier to understand than the equivalent programming-language text. However, complex pictures are confusing. A large, spaghetti-like flowchart is harder to understand than a properly structured program text. Pictures are inadequate for specifying complex sy...
specification;concurrency;state-transition diagrams;temporal logic
631204
Creation of Views for Reuse of Software with Different Data Representations.
Software reuse is inhibited by the many different ways in which equivalent data can be represented. We describe methods by which views can be constructed semi-automatically to describe how application data types correspond to the abstract types that are used in numerical generic algorithms. Given such views, specialize...
Introduction An algorithm should be like a mathematical theorem in the sense that once the algorithm has been developed, it should be reusable and should never have to be recoded manually. Like other engineering artifacts, however, algorithms that are used in an application must be adapted to fit the other parts of the...
visual programming;abstract data type;symbolic algebra;software reuse;data conversion;program transformation;generic algorithm
631218
Compositional Programming Abstractions for Mobile Computing.
AbstractRecent advances in wireless networking technology and the increasing demand for ubiquitous, mobile connectivity demonstrate the importance of providing reliable systems for managing reconfiguration and disconnection of components. Design of such systems requires tools and techniques appropriate to the task. Man...
Introduction The UNITY [1] approach to concurrency has been influential in the study of distributed systems in large part because of its emphasis on design aspects of the programming process, rather than simply serving as a tool for veri- fication. The technique has been used to derive concurrent algorithms for a wide ...
shared variables;formal methods;mobile computing;Mobile UNITY;transient interactions;synchronization;weak consistency
631246
Incremental Design of a Power Transformer Station Controller Using a Controller Synthesis Methodology.
AbstractIn this paper, we describe the incremental specification of a power transformer station controller using a controller synthesis methodology. We specify the main requirements as simple properties, named control objectives, that the controlled plant has to satisfy. Then, using algebraic techniques, the controller...
Introduction Motivations The Signal language [8] is developed for precise specification of real-time reactive systems [2]. In such systems, requirements are usually checked a posteriori using property verification and/or simulation techniques. Control theory of Discrete Event Systems (DES) allows to use constructive me...
optimal control;discrete event systems;signal;sigali;polynomial dynamical system;power plant;supervisory control problem
631250
Quantitative Analysis of Faults and Failures in a Complex Software System.
AbstractThe dearth of published empirical data on major industrial systems has been one of the reasons that software engineering has failed to establish a proper scientific basis. In this paper, we hope to provide a small contribution to the body of empirical knowledge. We describe a number of results from a quantitati...
Introduction Despite some heroic efforts from a small number of research centres and individuals (see, for example [Carman et al 1995], [Kaaniche and Kanoun 1996], [Khoshgoftaar et al 1996], [Ohlsson N and Alberg 1996], [Shen et al 1985]) there continues to be a dearth of published empirical data relating to the qualit...
software faults and failures;empirical studies;software metrics
631253
Architecture-Based Performance Analysis Applied to a Telecommunication System.
AbstractSoftware architecture plays an important role in determining software quality characteristics, such as maintainability, reliability, reusability, and performance. Performance effects of architectural decisions can be evaluated at an early stage by constructing and analyzing quantitative performance models, whic...
Introduction Performance characteristics (such as response time and throughput) are an integral part of the quality attributes of a software system. There is a growing body of research that studies the role of software architecture in determining different quality characteristics in general [12], [1], and performance c...
layered queueing networks;Unified Modeling Language UML;software architecture;software performance analysis;architectural patterns
633045
Scalable application layer multicast.
We describe a new scalable application-layer multicast protocol, specifically designed for low-bandwidth, data streaming applications with large receiver sets. Our scheme is based upon a hierarchical clustering of the application-layer multicast peers and can support a number of different data delivery trees with desir...
INTRODUCTION Multicasting is an efficient mechanism for packet delivery in one-many data transfer applications. It eliminates redundant packet replication in the network. It also decouples the size of the receiver set from the amount of state kept at any single node and therefore, is an useful primitive to scale multi-...
scalability;overlay networks;hierarchy;application layer multicast;peer-to-peer systems
633055
On the characteristics and origins of internet flow rates.
This paper considers the distribution of the rates at which flows transmit data, and the causes of these rates. First, using packet level traces from several Internet links, and summary flow statistics from an ISP backbone, we examine Internet flow rates and the relationship between the rate and other flow characterist...
INTRODUCTION Researchers have investigated many aspects of Internet tra#c, including characteristics of aggregate tra#c [8, 16], the sizes of files transferred, tra#c of particular applications [4] and routing stability [7, 17], to name a few. One area that has received comparatively little attention is the rate at whi...
flow rates;TCP;network measurement
633558
Quantum communication and complexity.
In the setting of communication complexity, two distributed parties want to compute a function depending on both their inputs, using as little communication as possible. The required communication can sometimes be significantly lowered if we allow the parties the use of quantum communication. We survey the main result...
Introduction The area of communication complexity deals with the following type of prob- lem. There are two separated parties, called Alice and Bob. Alice receives some input x 2 X, Bob receives some y 2 Y , and together they want to compute some function f(x; y). As the value f(x; y) will generally depend on both x an...
communication complexity;quantum computing
633565
Logical foundations of cafeOBJ.
This paper surveys the logical and mathematical foundations of CafeOBJ, which is a successor of the famous algebraic specification language OBJ but adds to it several new primitive paradigms such as behavioural concurrent specification and rewriting logic.We first give a concise overview of CafeOBJ. Then we focus on th...
Introduction CafeOBJ is an executable industrial strength algebraic specification language which is a modern successor of OBJ and incorporating several new algebraic specification paradigms. Its definition is given in [12]. CafeOBJ is intended to be mainly used for system specification, formal verification of specifica...
behavioural specification;institutions;CafeOBJ;algebraic specification
633574
Lower bounds for the rate of convergence in nonparametric pattern recognition.
We show that there exist individual lower bounds corresponding to the upper bounds for the rate of convergence of nonparametric pattern recognition which are arbitrarily close to Yang's minimax lower bounds, for certain "cubic" classes of regression functions used by Stone and others. The rates are equal to the ones of...
Introduction ),. be independent identically distributed R d f0; 1g-valued random variables. In pattern recognition (or classication) one wishes to decide whether the value of Y (the label) is 0 or 1 given the (d-dimensional) value of X (the observation), that is, one wants to nd a decision function g dened on the rang...
nonparametric pattern recognition;individual rates of convergence
633577
A geometric approach to leveraging weak learners.
AdaBoost is a popular and effective leveraging procedure for improving the hypotheses generated by weak learning algorithms. AdaBoost and many other leveraging algorithms can be viewed as performing a constrained gradient descent over a potential function. At each iteration the distribution over the sample given to the...
Introduction Algorithms like AdaBoost [7] that are able to improve the hypotheses generated by weak learning methods have great potential and practical benefits. We call any such algorithm a leveraging algorithm, as it leverages the weak learning method. Other examples of leveraging algorithms include bagging [3], arc-...
classification;boosting;learning;gradient descent;ensemble methods
633623
Phase transition for parking blocks, Brownian excursion and coalescence.
In this paper, we consider hashing with linear probing for a hashing table with m places, n items (n > m), and places. For a noncomputer science-minded reader, we shall use the metaphore of n cars parking on m places: each car ci chooses a place pi at random, and if pi is occupied, ci tries successively finds an empty ...
Introduction We consider hashing with linear probing for a hashing table with n places f1; 2; :::; ng, items places. Hashing with linear probing is a fundamental object in analysis of algorithms: its study goes back to the 1960's (Knuth [17], or Konheim & Weiss [19]) and is still active (Pittel [27], Knuth [18], or Fla...
brownian excursion;hashing with linear probing;coalescence;empirical processes;parking
633709
Feature selection with neural networks.
We present a neural network based approach for identifying salient features for classification in feedforward neural networks. Our approach involves neural network training with an augmented cross-entropy error function. The augmented error function forces the neural network to keep low derivatives of the transfer func...
Introduction Learning systems primary source of information is data. For numerical systems like Neural Networks (NNs), data are usually represented as vectors in a subspace of R k whose components - or features - may correspond for example to measurements performed on a physical system or to information gathered from t...
regularization;classification;feature selection;neural network
63382
Stochastic Petri Net Analysis of a Replicated File System.
The authors present a stochastic Petri net model of a replicated file system in a distributed environment where replicated files reside on different hosts and a voting algorithm is used to maintain consistency. Witnesses, which simply record the status of the file but contain no data, can be used in addition to or in p...
Introduction Users of distributed systems often replicate important files on different hosts, to protect them from a subset of host failures. The consistency of the files across the database is difficult to maintain manually, and so a data abstraction, the replicated file, has been introduced to automate the update pro...
performance reliability tradeoffs;concurrency control;majority protocols;distributed databases;fault tolerant computing;file status;voting algorithm;witnesses;stochastic Petri net model;replicated file system;distributed environment;petri nets
634719
Recurrence equations and their classical orthogonal polynomial solutions.
The classical orthogonal polynomials are given as the polynomial solutions pn(x) of the differential equation (x)y''(x) is a polynomial of at most second degree and (x) is a polynomial of first degree.In this paper a general method to express the coefficients An, Bn and Cn of the recurrence equation in terms of the giv...
Introduction Families of orthogonal polynomials p n (x) (corresponding to a positive-definite measure) satisfy a three-term recurrence equation of the form with C n A n A e.g. [6, p. 20]. Moreover, Favard's theorem states that the converse is also true. On the other hand, in practice one is often interested in an expli...
q-difference equation;structure formula;computer algebra;maple;differential equation
634745
Monotonicity and Collective Quantification.
This article studies the monotonicity behavior of plural determiners that quantify over collections. Following previous work, we describe the collective interpretation of determiners such as all, some and most using generalized quantifiers of a higher type that are obtained systematically by applying a type shifting op...
Introduction Traditional logical studies of quantification in natural language concentrated on the interactions between quantifiers and distributive predicates - predicates that describe properties of atomic entities. Generalized Quantifier Theory (GQT), as was applied to natural language semantics in the influential w...
monotonicity;determiner;plural;collectivity;generalized quantifier;type shifting
634756
Removing Node Overlapping in Graph Layout Using Constrained Optimization.
Although graph drawing has been extensively studied, little attention has been paid to the problem of node overlapping. The problem arises because almost all existing graph layout algorithms assume that nodes are points. In practice, however, nodes may be labelled, and these labels may overlap. Here we investigate how ...
Introduction Graph drawing has been extensively studied over the last fteen years. However, almost all research has dealt with graph layout in which the nodes are treated as points in the layout of graphs. Unfortunately, treating nodes as points is inadequate for many applications. For example, a textual label is frequ...
constrained optimization;graph layout;disjunctive constraints
634941
Capillary instability in models for three-phase flow.
Standard models for immiscible three-phase flow in porous media exhibit unusual behavior associated with loss of strict hyperbolicity. Anomalies were at one time thought to be confined to the region of nonhyperbolicity, where the purely convective form of the model is ill-posed. However, recent abstract results have re...
Introduction The standard model for three-phase ow in petroleum reservoirs is based on the two-component system of partial dierential equations @ @t @x @x @ @x U Date: November, 1999. This work was supported in part by: FAP-DF under Grant 0821 193 431/95; CAPES under Grant BEX0012/97-1; FEMAT under Grant 990003; CNPq u...
capillary pressure instability;nonunique Riemann solution;flow in porous media
634972
Automated techniques for provably safe mobile code.
We present a general framework for provably safe mobile code. It relies on a formal definition of a safety policy and explicit evidence for compliance with this policy which is attached to a binary. Concrete realizations of this framework are proof-carrying code, where the evidence for safety is a formal proof generate...
Introduction Integrating software components to form a reliable system is a long-standing fundamental problem in computer science. The problem manifests itself in numerous guises: (1) How can we dynamically add services to an operating system without compromising its integrity? (2) How can we exploit existing software ...
certifying compilers;type systems;typed assembly language;type safety;proof-carrying code
635014
Abstracting soft constraints.
Soft constraints are very flexible and expressive. However, they are also very complex to handle. For this reason, it may be reasonable in several cases to pass to an abstract version of a given soft constraint problem, and then to bring some useful information from the abstract problem to the concrete one. This will h...
Introduction Classical constraint satisfaction problems (CSPs) [18] are a very convenient and expressive formalism for many real-life problems, like scheduling, resource al- location, vehicle routing, timetabling, and many others [23]. However, many of these problems are often more faithfully represented as soft constr...
fuzzy reasoning;abstraction;constraint propagation;constraint solving;soft constraints
635238
Families of non-IRUP instances of the one-dimensional cutting stock problem.
In case of the one-dimensional cutting stock problem (CSP) one can observe for any instance a very small gap between the integer optimal value and the continuous relaxation bound. These observations have initiated a series of investigations. An instance possesses the integer roundup property (IRUP) if its gap is smalle...
Introduction The one-dimensional cutting stock problem (CSP) is as follows: Given an unlimited number of pieces of identical stock material of length L (e.g. wooden length, paper reels, etc.) the task is to cut b i pieces of length ' i for while minimizing the number of stock material pieces needed. Throughout this pap...
integer round-up property;continuous relaxation;one-dimensional cutting stock problem
635239
A framework for the greedy algorithm.
Perhaps the best known algorithm in combinatorial optimization is the greedy algorithm. A natural question is for which optimization problems does the greedy algorithm produce an optimal solution? In a sense this question is answered by a classical theorem in matroid theory due to Rado and Edmonds. In the matroid case,...
Introduction This paper concerns a classical algorithm in combinatorial optimization, the greedy algorithm. The MINIMAL SPANNING TREE problem, for example, is solved by the greedy algorithm: Given a nite graph G with weights on the edges, nd a spanning tree of G with minimum total weight. At each step in the greedy alg...
coxeter matroid;greedy algorithm;matroid
635251
Algorithms for the fixed linear crossing number problem.
several heuristics and an exact branch-and-bound algorithm are described for the fixed linear crossing number problem (FLCNP). An experimental study comparing the heuristics on a large set of test graphs is given. FLCNP is similar to the 2-page book crossing number problem in which the vertices of a graph are optimally...
Introduction Recently, several linear graph layout problems have been the subject of study. Given a set of vertices, the problem involves placing the vertices along a horizontal \node line" in the plane and then adding edges as specied by the interconnection pattern. The node line, or \spine", divides the plane into tw...
linear layout;neural network;crossing number;branch-and-bound;heuristic
635468
Some recent advances in validated methods for IVPs for ODEs.
Compared to standard numerical methods for initial value problems (IVPs) for ordinary differential equations (ODEs), validated methods (often called interval methods) for IVPs for ODEs have two important advantages: if they return a solution to a problem, then (1) the problem is guaranteed to have a unique solution, an...
Preprint submitted to Elsevier Preprint 20 November 2000 is D. The condition (2) permits the initial value to be in an interval, rather than specifying a particular value. We assume that the representation of f contains a nite number of constants, variables, elementary operations, and standard functions. Since we assum...
wrapping effect;interval methods;validated methods;QR algorithm;ordinary differential equations;simultaneous iteration;taylor series;initial value problems;stability
635471
Differential algebraic systems anew.
It is proposed to figure out the leading term in differential algebraic systems more precisely. Low index linear systems with those properly stated leading terms are considered in detail. In particular, it is asked whether a numerical integration method applied to the original system reaches the inherent regular ODE wi...
Introduction When dealing with standard linear time-varying coe-cient DAEs and their adjoint equations one is confronted with a kind of unsightly dissymmetry. These equations are of dierent type. In [3], more precise formulations E(PE Humboldt University, Institute of Mathematics, D-10099 Berlin, Germany (iam@mathemati...
numerical integration methods;differential algebraic equations;abstract differential algebraic equations;partial differential algebraic equations
635794
Non-nested multi-level solvers for finite element discretisations of mixed problems.
We consider a general framework for analysing the convergence of multi-grid solvers applied to finite element discretisations of mixed problems, both of conforming and nonconforming type. As a basic new feature, our approach allows to use different finite element discretisations on each level of the multi-grid hierarch...
Introduction Multi-grid methods are among the most ecient and most popular solvers for nite element discretisations of elliptic partial dierential equations. Their convergence theory in the case of symmetric operators and nested conforming nite element methods is well-established; see for example the books [7, 17, 30] ...
finite element discretisation;multi-level method;stokes problem;mixed problems
635802
Approximating most specific concepts in description logics with existential restrictions.
Computing the most specific concept (msc) is an inference task that allows to abstract from individuals defined in description logic (DL) knowledge bases. For DLs that allow for existential restrictions or number restrictions, however, the msc need not exist unless one allows for cyclic concepts interpreted with the gr...
Introduction The most specic concept (msc) of an individual b is a concept description that has b as instance and is the least concept description (w.r.t. subsump- tion) with this property. Roughly speaking, the msc is the concept description that, among all concept descriptions of a given DL, represents b best. Closel...
description logics;non-standard inferences;most specific concepts
635905
An efficient direct solver for the boundary concentrated FEM in 2D.
The boundary concentrated FEM, a variant of the hp-version of the finite element method, is proposed for the numerical treatment of elliptic boundary value problems. It is particularly suited for equations with smooth coefficients and non-smooth boundary conditions. In the two-dimensional case it is shown that the Chol...
Introduction The recently introduced boundary concentrated nite element method of [8] is a numerical method that is particularly suited for solving elliptic boundary value problems with the following two properties: a) the coe-cients of the equations are analytic so that, by elliptic regularity, the solution is globall...
hp-finite element methods;direct solvers;schur complement;meshes refined towards boundary
636260
Computation of the simplest normal forms with perturbation parameters based on Lie transform and rescaling.
Normal form theory is one of the most power tools for the study of nonlinear differential equations, in particular, for stability and bifurcation analysis. Recently, many researchers have paid attention to further reduction of conventional normal forms (CNF) to so called the simplest normal form (SNF). However, the com...
Introduction Normal form theory for dierential equations can be traced back to the original work of one hundred years ago, and most credit should be given to Poincare [1]. The theory plays an important role in the study of dierential equations Preprint submitted to Elsevier Preprint 25 May 2001 related to complex behav...
nonlinear transformation;the simplest normal form SNF;rescaling;computer algebra;differential equation;lie transform;unfolding
636361
Approximate Nonlinear Filtering for a Two-Dimensional Diffusion with One-Dimensional Observations in a Low Noise Channel.
The asymptotic behavior of a nonlinear continuous time filtering problem is studied when the variance of the observation noise tends to 0. We suppose that the signal is a two-dimensional process from which only one of the components is noisy and that a one-dimensional function of this signal, depending only on the unno...
Introduction Due to its vaste application in engineering, the problem of filtering a random signal X t from noisy observations of a function h(X t ) of this signal has been considered by several authors. In particular, the case of small observation noise has been widely studied, and several articles are devoted to the ...
stochastic differential models;approximate filters;nonlinear filtering
636409
An analog characterization of the Grzegorczyk hierarchy.
We study a restricted version of Shannon's general purpose analog computer in which we only allow the machine to solve linear differential equations. We show that if this computer is allowed to sense inequalities in a differentiable way, then it can compute exactly the elementary functions, the smallest known recursive...
INTRODUCTION The theory of analog computation, where the internal states of a computer are continuous rather than discrete, has enjoyed a recent resurgence of interest. This stems partly from a wider program of exploring alternative approaches to computation, such as quantum and DNA computation; partly as an idealizati...
elementary functions;dynamical systems;subrecursive functions;recursion theory;analog computation;primitive recursive functions;grzegorczyk hierarchy;differential equations
636581
A polytopal generalization of Sperner''s lemma.
We prove the following conjecture of Atanassov (Studia Sci. Math. Hungar. 32 (1996), 71-74). Let T be a triangulation of a d-dimensional polytope P with n vertices v1, v2,...., vn. Label the vertices of T by 1,2,..., n in such a way that a vertex of T belonging to the interior of a face F of P can only be labelled by j...
Introduction Sperner's Lemma is a combinatorial statement about labellings of triangulated simplices whose claim to fame is its equivalence with the topological xed-point theorem of Brouwer [8, 16]. In this paper we prove a generalization of Sperner's Lemma that settles a conjecture proposed by K.T. Atanassov [2]. Cons...
sperner's lemma;path-following;polytopes;simplicial algorithms
636696
An Efficient Protocol for Authenticated Key Agreement.
This paper proposes an efficient two-pass protocol for authenticated key agreement in the asymmetric (public-key) setting. The protocol is based on Diffie-Hellman key agreement and can be modified to work in an arbitrary finite group and, in particular, elliptic curve groups. Two modifications of this protocol are also...
Introduction Key establishment is the process by which two (or more) entities establish a shared secret key. The key is subsequently used to achieve some cryptographic goal such as confidentiality or data integrity. Broadly speaking, there are two kinds of key establishment protocols: key transport protocols in which a...
diffie-hellman;key confirmation;authenticated key agreement;elliptic curves
636898
Modeling random early detection in a differentiated services network.
An analytical framework for modeling a network of random early detection (RED) queues with mixed traffic types (e.g. TCP and UDP) is developed. Expressions for the steady-state goodput for each flow and the average queuing delay at each queue are derived. The framework is extended to include a class of RED queues that ...
INTRODUCTION The diverse and changing nature of service requirements among Internet applications mandates a network architecture that is both flexible and capable of differentiating between the needs of different applications. The traditional Internet architecture, however, offers best-effort service to all traffic. In...
differentiated services;performance analysis;network modeling;random early detection;UDP;TCP
637151
Massively parallel fault tolerant computations on syntactical patterns.
The general capabilities of reliable computations in linear cellular arrays are investigated in terms of syntactical pattern recognition. We consider defects of the processing elements themselves and defects of their communication links. In particular, a processing element (cell) is assumed to behave as follows. Depend...
Introduction Nowadays it becomes possible to build massively parallel computing systems that consist of hundred thousands of processing elements. Each single component is subject to failure such that the probability of misoperations and loss of function of the whole system increases with the number of its elements. It ...
static and dynamic defects;syntactical pattern recognition;fault-tolerance;link failures;cellular arrays
637236
A case study of OSPF behavior in a large enterprise network.
Open Shortest Path First (OSPF) is widely deployed in IP networks to manage intra-domain routing. OSPF is a link-state protocol, in which routers reliably flood "Link State Advertisements" (LSAs), enabling each to build a consistent, global view of the routing topology. Reliable performance hinges on routing stability,...
INTRODUCTION Operational network performance assurances hinge on the stability and performance of the routing system. Understanding behavior of routing protocols is crucial for better operation and management of IP networks. In this pa- per, we focus on Open Shortest Path First (OSPF) [1], a widely deployed Interior Ga...
routing;LSA traffic;OSPF;enterprise networks
637247
Active probing using packet quartets.
A significant proportion of link bandwidth measurement methods are based on IP's ability to control the number of hops a packet can traverse along a route via the time-to-live (TTL) field of the IP header. A new delay variation based path model is introduced and used to analyse the fundamental networking effects underl...
INTRODUCTION Recent papers of Lai and Baker [1] and Dovrolis [2] identify two primary network effects at the foundation of existing probing techniques. The one-packet methods are based on the assumption that the transmission delay is linear in the packet size. The idea was first introduced by V. Jacobson in his pathcha...
active probing;cross-traffic;delay variation;bottleneck bandwidth;TTL;internet measurement
637321
The monadic theory of morphic infinite words and generalizations.
We present new examples of infinite words which have a decidable monadic theory. Formally, we consider structures {N, >, P} which expand the ordering {N, >} of the natural numbers by a unary predicate P; the corresponding infinite word is the characteristic 0-1-sequence xp of P. We show that for a morphic predicate P t...
Introduction In this paper we study the following decision problem about a xed !-word x: Given a Buchi automaton A, does A accept x? If the problem (Acc x ) is decidable, this means intuitively that one can use x as external oracle information in nonterminating nite-state systems and still keep decidability results on ...
morphic predicates;second-order
637371
New Interval Analysis Support Functions Using Gradient Information in a Global Minimization Algorithm.
The performance of interval analysis branch-and-bound global optimization algorithms strongly depends on the efficiency of selection, bounding, elimination, division, and termination rules used in their implementation. All the information obtained during the search process has to be taken into account in order to incre...
Introduction . In this paper the problem of nding the global minimum f of a real valued one-dimensional continuously dierentiable function f and the corresponding set S of global minimizers is considered, i.e.: In contrast to one-dimensional local optimization problems which were very well studied in the past, the un...
interval arithmetic;global optimization;branch-and-bound
637568
Steps toward accurate reconstructions of phylogenies from gene-order data.
We report on our progress in reconstructing phylogenies from gene-order data. We have developed polynomial-time methods for estimating genomic distances that greatly improve the accuracy of trees obtained using the popular neighbor-joining method; we have also further improved the running time of our GRAPPA software su...
INTRODUCTION Genome rearrangements. Modern laboratory techniques can yield the ordering and strandedness of genes on a chromosome, allowing us to represent each chromosome by an ordering of signed genes (where the sign indicates the strand). Evolutionary events can alter these orderings through rearrangements such as i...
breakpoint analysis;evolutionary distance;genome rearrangement;inversion distance;distance estimator;ancestral genome
637759
Experiences in modeling and simulation of computer architectures in DEVS.
The use of traditional approaches to teach computer organization usually generates misconceptions in the students. The simulated computer ALFA-1 was designed to fill this gap. DEVS was used to attack this complex design of the chosen architecture, allowing for the definition and integration of individual components. DE...
Figure 1. Organization of the Integer Unit. This RISC processor is provided with 520 integer registers. Eight of them are global (RegGlob, shared by every procedure), and the remaining 512 are divided in windows of 24 registers each (RegBlock). Each window includes input, output and local registers for every procedure...
simulation in education;computer organization;applications of DEVS methodology;DEVS models