Monoid-labeled transition systems

Given a -complete (semi)lattice , we consider -labeled transition systems as coalgebras of a functor ⁽⁻⁾, associating with a set X the set ^X of all -fuzzy subsets. We describe simulations and bisimulations of -coalgebras to show that L⁽⁻⁾ weakly preserves nonempty kernel pairs iff it weakly preserves nonempty pullbacks iff L is join infinitely distributive (JID).Exchanging for a commutative monoid , we consider the functor ⁽⁻⁾_ω which associates with a set X all finite multisets containing elements of X with multiplicities m M. The corresponding functor weakly preserves nonempty pullbacks along injectives iff 0 is the only invertible element of , and it preserves nonempty kernel pairs iff is refinable, in the sense that two sum representations of the same value, r₁ + … + r_m = c₁ + … + c_n, have a common refinement matrix (m_{(i, j)}) whose k-th row sums to r_k and whose l-th column sums to c_l for any 1≤ k ≤ m and 1 ≤ l ≤ n.     

Distribution Dimensions in Software Development Projects: A Taxonomy

Distribution in software development projects is a complex phenomenon with many dimensions. In addition to the obvious physical dimension entailed by geographically dispersed project personnel and resources, projects must contend with organizational distribution among various company departments, for example, as well as temporal and stakeholder distributions. A review of the literature on globally distributed software development projects produced a preliminary taxonomy based on a dimensional analysis of distribution. Developers can use this taxonomy to identify and visualize their project's distribution dimensions and scopes. A real-world case study of the taxonomy's use illuminates its value, as well as common challenges and possible solutions to distribution problems.This article is part of a special issue on Global Software Development.     

Measurement of 8-VSB DTV transmitter emissions

This paper describes the theory and procedures necessary to understand and measure the emissions of an 8-VSB DTV transmitter. It starts with the FCC's requirements, then moves to the nature of the 8-VSB signal. The noise bandwidth of the signal is calculated and it is demonstrated how to relate this bandwidth to the FCC's requirement that the out of channel emissions be measured in a 500 kHz bandwidth. This discussion justifies the measurement procedure provided, showing how a spectrum analyzer or other specialty 8-VSB measurement equipment may be used to determine compliance with the FCCs out of channel emissions requirements. Methods of achieving measurements to the FCCs -110 dB specification are discussed. Effects of several factors that may affect measurement accuracy including measurement bandwidth, intermodulation, noise floor, logarithmic amplifier error, detector error and mismatch errors are discussed. An appendix gives an easy method for approximating the power of the 8-VSB signal by adding 12 dB to the pilot signal amplitude. The appendix also derives the relationship between the amplitude of the pilot signal and the bandwidth-dependent amplitude of the head of the 8-VSB signal     

Neurolinguistics programming: Method or myth?

The preferred modality by which 50 right-handed female college students encoded experience was assessed by recordings of conjugate eye movements, content analysis of S's verbal report, and S's self-report. Contrary to the prediction of the theory of neurolinquistics programming (NLP), kappa analyses failed to reveal any agreement of the 3 assessment methods. Each assessment method was also shown to be biased toward revealing a particular representational modality. The application of certain principles of NLP in counseling settings is therefore questioned. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Covarieties and complete covarieties

We present two ways to define covarieties and complete covarieties, i.e. covarieties that are closed under total bisimulation: by closure operators and by subcoalgebras of coalgebras.     

Preface: Volume 82, Issue 1

This volume contains the Proceedings of the Sixth Workshop on Coalgebraic Methods in Computer Science (CMCS'03). The workshop was held in Warsaw, Poland on April 5 and 6, 2003, as a satellite event to the European Joint Conference on Theory and Practice of Software (ETAPS'03). The aim of the CMCS workshop series is to bring together researchers with a common interest in the theory of coalgebras and its applications. Previous workshops have been organized in Lisbon (1998), Amsterdam (1999), Berlin (2000), Genoa (2001), and Grenoble (2002).Coalgebras have been found extremely useful for capturing state-based dynamical systems, such as transition systems, automata, process calculi, and class-based systems. The theory of coalgebras has developed into a field of its own interest, presenting a deep mathematical foundation, a growing domain of applications and interactions with various other fields, such as reactive and interactive systems theory, object oriented and concurrent programming, formal system specification, modal logic, dynamical systems, control systems, category theory, algebra, analysis, etc.The program committee of CMCS'03 consisted of

Jiri Adámek	Technical University of Braunschweig, Germany
Corina Cîrstea	Oxford University, UK
H. Peter Gumm	University of Marburg, Germany, (chair)
Bart Jacobs	University of Nijmwegen, The Netherlands
Alexander Kurz	University of Leicester, UK
Marina Lenisa	University of Udine, Italy
Ugo Montanari	University of Pisa, Italy
Larry Moss	Indiana University, Bloomington, USA
Ataru T. Nakagawa	Software Research Associates, Tokyo, Japan
Horst Reichel	Technical University Dresden, Germany
Grigore Rosu	University of Illinois, Urbana, USA
Jan Rutten	CWI, Amsterdam, The Netherlands
James Worrell	Tulane University, New Orleans, USA

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The papers were refereed by the program committee and by several outside referees, whose help is gratefully acknowledged. The invited speakers at the conference were

Zoltán Ésik	University of Szeged, Hungary
Vaughan Pratt	Stanford University, USA

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These proceedings are being published as volume 82.1 in the series Electronic Notes in Theoretical Computer Science (ENTCS). Printed copies, containing preliminary versions of the articles in these proceedings were distributed to the participants of the conference. The proceedings of the previous CMCS workshops appeared as ENTCS Volumes 11, 19, 33, 44.1, and 65.1.We are grateful to ENTCS for their continuing support, in particular to Mike Mislove, Managing Editor of the ENTCS series.For the sixth time, CMCS has been organized as satellite event to ETAPS. We are very grateful to the ETAPS organizers, especially to Damian Niwinski, for taking care of all the local organization and for accommodating all our special requests.

Marburg, May 27, 2003

H. Peter Gumm

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Equational and implicational classes of coalgebras

If F :Set→Set is a functor which is bounded and preserves weak generalized pullbacks then a class of F-coalgebras is a covariety, i.e., closed under (homomorphic images), (sub-coalgebras) and ∑ (sums), if and only if it can be defined by a set of “coequations”. Similarly, quasi-covarieties, i.e., classes closed under and ∑, can be characterized by implications of coequations. These results are analogous to the theorems of Birkhoff and of Mal'cev in classical universal algebra.