bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proof rules for recursive procedures
Authors: Hesselink Wim H. 
Published: February 2005

Abstract
Four proof rules for recursive procedures in a Pascal-like language are presented. The main rule deals with total correctness and is based on results of Gries and Martin. The rule is easier to apply than Martin's. It is introduced as an extension of a specification format for Pascal-procedures, with its associated correctness and invocation rules. It uses well-founded recursion and is proved under the postulate that a procedure is semantically equal to its body.
This rule for total correctness is compared with Hoare's rule for partial correctness of recursive procedures, in which no well-founded relation is needed. Both rules serve to prove correctness, i.e. sufficiency of certain preconditions. There are also two rules for proving necessity of preconditions. These rules can be used to give formal proofs of nontermination and refinement. They seem to be completely new.
Petri net based verification of distributed algorithms: An example
Authors: Kindler Ekkart , Reisig Wolfgang , Völzer Hagen , Walter Rolf 
Published: February 2005

Abstract

A technique to model and to verify distributed algorithms is suggested. This technique (based on Petri nets) reduces the modelling and analysis effort to a reasonable level. The paper outlines the technique using the example of a typical network algorithm, the
echo algorithm
.
A mechanically verified incremental garbage collector
Authors: Russinoff David M. 
Published: February 2005

Abstract
As an application of a system designed for concurrent program verification, we describe a formalisation and mechanical proof of the correctness of Ben-Ari's incremental garbage collection algorithm. The proof system is based on the Manna-Pnueli model of concurrency and is implemented as an extension of the Boyer-Moore prover. The correctness of the garbage collector is represented by two theorems, stating a) that nothing except garbage is ever collected (safety), and b) that all garbage is eventually collected (liveness). We compare our mechanised treatment with several published proofs of the same results.
Inductive families
Authors: Dybjer Peter 
Published: February 2005

AbstractA general formulation of inductive and recursive definitions in Martin-Löf's type theory is presented. It extends Backhouse's ‘Do-It-Yourself Type Theory’ to include inductive definitions of families of sets and definitions of functions by recursion on the way elements of such sets are generated. The formulation is in natural deduction and is intended to be a natural generalisation to type theory of Martin-Löf's theory of iterated inductive definitions in predicate logic.Formal criteria are given for correct formation and introduction rules of a new set former capturing definition by strictly positive, iterated, generalised induction. Moreover, there is an inversion principle for deriving elimination and equality rules from the formation and introduction rules. Finally, there is an alternative schematic presentation of definition by recursion.The resulting theory is a flexible and powerful language for programming and constructive mathematics. We hint at the wealth of possible applications by showing several basic examples: predicate logic, generalised induction, and a formalisation of the untyped lambda calculus.
Coquand's calculus of constructions: A mathematical foundation for a proof development system
Authors: Seldin Jonathan P. 
Published: February 2005

AbstractThe calculus of constructions of Coquand, which is a version of higher order typedλ-calculus based on the dependent function type, is considered from the perspective of its use as the mathematical foundation for a proof development system. The paper considers formulations of the calculus, the underlying consistency of the formalism (i.e., the strong normalisation theorem), and the proof theory of adding assumptions for notions from logic and set theory. Proofs are not given, but references to them are.
Denotational semantics of an object-oriented programming language with explicit wrappers
Authors: Hense Andreas V. 
Published: February 2005

AbstractObject-oriented languages have traditionally been described by method-lookup-semantics. Their denotational semantics have appeared and matured only recently. Cook's wrapper semantics without state shows the essence of inheritance much clearer than method-lookup-semantics.In this article, we show how wrapper semantics can describe an object-oriented languagewith statewhile keeping its original clear structure. We then extend our object-oriented language by so calledexplicit wrappers. Wrappers that are used for the description of the semantics of an “ordinary” object-oriented language emerge from the semantics level and are included into the language itself. This unusual step is being justified by a greater reusability of code. With explicit wrappers and single inheritance, one variety of multiple inheritance can be expressed.
Asynchronous communication model based on linear logic
Authors: Kobayashi Naoki , Yonezawa Akinori 
Published: February 2005

AbstractWe propose a new framework called ACL for concurrent computation based on linear logic. ACL is a kind oflinear logic programmingframework, where its operational semantics is described in terms ofproof constructionin linear logic. We also give a model-theoretic semantics based onphase semantics, a model of linear logic. Our framework well captures concurrent computation based on asynchronous communication. It will, therefore, provide us with a new insight into other models of asynchronous concurrent computation from alogicalpoint of view. We also expect ACL to become a formal framework for analysis, synthesis and transformation of concurrent programs by the use of techniques for traditional logic programming. ACL's attractive features for concurrent programming paradigms are also discussed.
An action-based formal model for concurrent real-time systems
Authors: Fidge C. J. , Wellings A. J. 
Published: February 2005

AbstractAction systems are a formalism for representing concurrent behaviours, based on interleaved atomic actions. We show how this model can be used to represent time-consuming, pre-emptible actions with real-time constraints. A development procedure is described which captures the steps programmers typically undertake in the design of real-time multi-tasking systems.
A logic for reasoning about time and reliability
Authors: Hansson Hans , Jonsson Bengt 
Published: February 2005

AbstractWe present a logic for stating properties such as, “after a request for service there is at least a 98% probability that the service will be carried out within 2 seconds”. The logic extends the temporal logic CTL by Emerson, Clarke and Sistla with time and probabilities. Formulas are interpreted over discrete time Markov chains. We give algorithms for checking that a given Markov chain satisfies a formula in the logic. The algorithms require a polynomial number of arithmetic operations, in size of both the formula and the Markov chain. A simple example is included to illustrate the algorithms.
Refinement of a typed WAM extension by polymorphic order-sorted types
Authors: Beierle Christoph , Börger Egon 
Published: February 2005

Abstract
We refine the mathematical specification of a WAM extension to typeconstraint logic programming given in [BeB96]. We provide a full specification and correctness proof of the PROTOS Abstract Machine (PAM), an extension of the WAM by polymorphic order-sorted unification as required by the logic programming language PROTOS-L, by refining the abstract type constraints used in [BeB96] to the polymorphic order-sorted types of PROTOS-L. This allows us to develop a detailed and mathematically precise account of the PAM's compiled type constraint representation and solving facilities, and to extend the correctness theorem to compilation on the fully specified PAM.
Compositional minimisation of finite state systems using interface specifications
Authors: Graf Susanne , Steffen Bernhard , Lüttgen Gerald 
Published: February 2005

AbstractWe present a method for thecompositional constructionof theminimal transition systemthat represents the semantics of a given distributed system. Our aim is to control thestate explosioncaused by the interleavings of actions of communicating parallel components byreduction stepsthat exploitglobalcommunication constraints given in terms ofinterface specifications.Theeffectof the method, which is developed forbisimulation semanticshere, depends on the structure of the distributed system under consideration, and theaccuracyof the interface specifications. However, itscorrectnessis independent of the correctness of the interface specifications provided by the program designer.
Verifying a distributed list system: A case history
Authors: Krogdahl Stein , Lysne Olav 
Published: February 2005

AbstractThe background for this paper is twofold: One is the definition of a caching protocol for shared memory parallel computers called SCI, and the other is the usage of rewriting techniques in program verification. The paper concentrates on a linked list system, which is a central aspect of the caching protocol. We first describe an informal proof of this system, including a rather large invariant. Thereafter we show how the list system and the invariant can both be described in the formalism of rewriting logic, and we use this to carry through a significant part of the verification mechanically, using the OBJ3 interpreter.
Integration of parametric and “ad hoc” second order polymorphism in a calculus with subtyping
Authors: Castagna Giuseppe 
Published: February 2005

AbstractIn this paper we define an extension ofF≤[CUG92] to which we add functions that dispatch on different terms according to the type they receive as argument. In other words, we enrich the explicit parametric polymorphism ofF≤by an explicit “ad hoc” polymorphism (according the classification of [Str67]). We prove that the calculus we obtain, calledF≤&, enjoys the properties of Church-Rosser and Subject Reduction and that its proof system is coherent. We also define a significant subcalculus for which the subtyping is decidable. This extension has not only a logical interest but it is strongly motivated by the foundation of a broadly used programming style: object-oriented programming. The connections betweenF≤&and object-oriented languages are widely stressed, and the modelling byF≤&of some features of the object-oriented style is described, continuing the work of [CGL96].
Compositional verification of real-time systems with Explicit Clock Temporal Logic
Authors: Zhou Ping , Hooman Jozef , Kuiper Ruurd 
Published: February 2005

AbstractTo specify and verify real-time systems, we consider a real-time version of temporal logic called Explicit Clock Temporal Logic. Timing properties are specified by extending the classical framework of temporal logic with a special variable which explicitly refers to a global notion of time. Programs are written in an Occam-like real-time language with synchronous message passing. To show that a program satisfies a specification, we formulate a proof system which is proved to be sound and relatively complete. The proof system is compositional, which makes it possible to decompose the design of a large system into the design of subsystems. This is shown by the verification of a small part of an avionics system.
Brief report: The effects of condom insistence on the perceptions of adolescents in first time and repeated occasions of sexual intercourse
Authors: Turk Don R. , Hocking John E. 
Published: February 2005

AbstractThe research reported here replicated Hocking et al. (Journal of Adolescence 22 (1999) 355) and further examined the effects of insisting on condom usage, by expanding the experimental conditions under which condom use occurs to include repeated sexual encounters in ongoing relationships. In Study 1, Hocking et al. (Journal of Adolescence 22 (1999) 355) results were replicated. In Study 2, using identical procedures, participants imagined engaging in sexual intercourse in which their partner of 3 months either insisted on the continued use of a condom or requested that no condom be used. Results for Study 2 were such that participants in the condom insistence conditions reported greater feelings of positivity about themselves, their partners, and the sexual experience, than participants whose partners did not insist on condom use during sex.
A comparison of bottling alternatives in the pharmaceutical industry
Authors: Teunter Ruud H. , Flapper Simme Douwe P. 
Published: February 2005

AbstractThis paper presents the results of a case study in a batch production facility for biological vaccines with possibilities for rework. The problem considered is that of finding the best bottling alternative for produced batches when these have to undergo several lengthy quality tests related to the foregoing production processes. Produced batches can be bottled directly after production when the results of these test are completely unknown, after some positive (intermediate) test results are known, or after all test have been completed with positive results. When waiting in order to be bottled, a batch has to stay in the production tank. Alternatives that start the bottling process quickly after production have the advantages of a relatively low tank capacity requirement and of a relatively small flow time if all test results are positive. However, a produced batch can only be reworked as long as it has not been bottled. So fast bottling reduces the possibilities for rework and therefore reduces the production yield. We present performance measures for comparing the different alternatives and derive closed form expressions for them. We also present the results obtained for the considered case.
Calling emergency medical services during drug overdose: an examination of individual, social and setting correlates
Authors: Tobin Karin E. , Davey Melissa A. , Latkin Carl A. 
Published: February 2005

ABSTRACTAims  The purpose of this study was to examine individual, social and setting correlates of calling the emergency number, 911, during an overdose.Design  Cross‐sectional survey.Methods  A sample of 397 current or former drug users in Baltimore, MD, USA who reported having ever witnessed an overdose.Findings  Participants reported calling an ambulance in 23% of the overdose cases. Results from multivariate logistic regression indicate that having ever overdosed and having four or more bystanders present independently decreased the likelihood of calling 911. Having ever witnessed a fatal overdose and having any female bystanders present increased the likelihood of calling 911. There was a significant interaction between fear of arrest and prior exposure to the police. Setting of the overdose (public versus private) was not associated with calling 911 after controlling for other factors.Conclusions  These findings suggest that in addition to personal characteristics of witnesses, social factors influence calling 911. Intervention at the social level may be a viable means to increase bystander helping behaviors.
Tests of causal linkages between cannabis use and psychotic symptoms
Authors: Fergusson David M. , Horwood L. John , Ridder Elizabeth M. 
Published: February 2005

ABSTRACTAim  To examine possible causal linkages between cannabis use and psychosis using data gathered over the course of a 25‐year longitudinal study.Design  A 25‐year longitudinal study of the health, development and adjustment of a birth cohort of 1265 New Zealand children (635 males, 630 females).Setting  The Christchurch Health and Development Study, a general community sample.Participants  A total of 1055 participants from the Christchurch Health and Development Study (CHDS) cohort for whom data on cannabis use and psychotic symptoms were available on at least one occasion from 18, 21 and 25 years.Measurements  As part of this study, data were gathered on frequency of cannabis use and psychotic symptoms at ages 18, 21 and 25 years.Findings  Regression models adjusting for observed and non‐observed confounding suggested that daily users of cannabis had rates of psychotic symptoms that were between 1.6 and 1.8 times higher (P < 0.001) than non‐users of cannabis. Structural equation modelling suggested that these associations reflected the effects of cannabis use on symptom levels rather than the effects of symptom levels on cannabis use.Conclusions  The results of the present study add to a growing body of evidence suggesting that regular cannabis use may increase risks of psychosis. The present study suggests that: (a) the association between cannabis use and psychotic symptoms is unlikely to be due to confounding factors; and (b) the direction of causality is from cannabis use to psychotic symptoms.
Beauty is in the eye of the examiner: reaching agreement about physical signs and their value
Authors: Joshua A. M. , Celermajer D. S. , Stockler M. R. 
Published: February 2005

Abstract Despite advances in other areas, evidence‐based medicine is yet to make substantial inroads on the standard medical physical examination. We have reviewed the evidence about the accuracy and reliability of the physical examination and common clinical signs. The physical examination includes many signs of marginal accuracy and reproducibility. These may not be appreciated by clinicians and could adversely affect decisions about treatment and investigations or the teaching and examination of students and doctors‐in‐training. We provide a selected summary of the reliability and accuracy as well as important messages of key findings in the physical examination. (Intern Med J 2005; 35: 178–187)
Functional characterization of rat ρ2 subunits expressed in HEK 293 cells
Authors: Alakuijala Anniina , TalviOja Katri , Pasternack Arja , Pasternack Michael 
Published: February 2005

AbstractGABAC receptors are thought to be homo‐ or heteropentamers composed of ρ1, ρ2 and ρ3 subunits. Previous work on rat ρ2 subunits expressed in Xenopus oocytes has suggested that they do not form functional homo‐oligomeric GABAC receptors, but do combine with ρ1 or ρ3 subunits to form hetero‐oligomers. These findings are difficult to interpret because both human and mouse ρ2 subunits do form functional homo‐oligomeric receptors. Also, many regions of the rat brain express solely ρ2 subunit transcripts which, according to presently available evidence, would not result in expression of functional GABAC receptors. We show here that homomeric rat ρ2 receptors can be expressed in HEK 293 cells. Homo‐oligomeric rat ρ2 receptors expressed in mammalian cells matured slowly and displayed small but detectable GABA‐induced currents with slow kinetics. Rat ρ2 receptors also had a decreased sensitivity to picrotoxin and a marked sensitivity to the GABAC receptor agonist cis‐aminocrotonic acid. Our results demonstrate for the first time the expression of functional homomeric rat ρ2 receptors, and suggest that ρ2 subunits may contribute to brain function, including in areas not expressing other ρ subunits.
The removal of extracellular calcium: a novel mechanism underlying the recruitment of N‐methyl‐d‐aspartate (NMDA) receptors in neurotoxicity
Authors: Xin Wen‐Kuan , Zhao Xiao‐Han , Xu Jindong , Lei Gang , Kwan Chun L. , Zhu Kang‐Min , Cho Jae‐Sung , Duff Missy , Ellen Richard P. , McCulloch Christopher A. G. , Yu Xian‐Min 
Published: February 2005

AbstractThe involvement of NMDA‐type glutamate receptor in neuronal injury established in experimental stroke and neurotrauma models has been recently challenged by failures in treatment of stroke/neurotrauma patients with NMDA receptor antagonists. NMDA receptor activity is known to be essential for mediating a multitude of physiological functions. However, how NMDA receptors are recruited to cause neuronal injury remains unclear. Here we report that the time period during which initial NMDA receptor up‐regulation occurs is critical for the recruitment of NMDA receptors causing neuronal injury during extracellular calcium (Ca2+) reperfusion in cultured hippocampal neurons, and represents the key period for neuronal protection by NMDA receptor antagonists. Furthermore, we identified that via intracellular sodium (Na+), extracellular Ca2+ depletion induces the up‐regulation of NMDA receptor gating. Taken together, our study provides direct experimental evidence suggesting that determination of when and how NMDA receptors are recruited to cause neurotoxicity is essential for guiding treatment via antagonism of NMDA receptor functions.
A TASK‐like pH‐ and amine‐sensitive ‘leak’ K+ conductance regulates neonatal rat facial motoneuron excitability in vitro
Authors: Larkman Philip M. , Perkins Emma M. 
Published: February 2005

AbstractA ‘leak’ potassium (K+) conductance (gKLeak) modulated by amine neurotransmitters is a major determinant of neonatal rat facial motoneuron excitability. Although the molecular identity of gKLeak is unknown, TASK‐1 and TASK‐3 channel mRNA is found in facial motoneurons. External pH, across the physiological range (pH 6–8), and noradrenaline (NA) modulated a conductance that displayed a relatively linear current/voltage relationship and reversed at the K+ equilibrium potential, consistent with inhibition of gKLeak. The pH‐sensitive current (IpH), was maximal around pH 8, fully inhibited near pH 6 and was described by a modified Hill equation with a pK of 7.1. The NA‐induced current (INA) was occluded at pH 6 and enhanced at pH 7.7. The TASK‐1 selective inhibitor anandamide (10 µm), its stable analogue methanandamide (10 µm), the TASK‐3 selective inhibitor ruthenium red (10 µm) and Zn2+ (100–300 µm) all failed to alter facial motoneuron membrane current or block INA or IpH. Isoflurane, a volatile anaesthetic that enhances heteromeric TASK‐1/TASK‐3 currents, increased gKLeak. Ba2+, Cs+ and Rb+ blocked INA and IpH voltage‐dependently with maximal block at hyperpolarized potentials. 4‐Aminopyridine (4‐AP, 4 mm) voltage‐independently blocked INA and IpH. In summary, gKLeak displays some of the properties of a TASK‐like conductance. The linearity of gKLeak and an independence of activation on external [K+] suggests against pH‐sensitive inwardly rectifying K+ channels. Our results argue against principal contributions to gKLeak by homomeric TASK‐1 or TASK‐3 channels, while the potentiation by isoflurane supports a predominant role for heterodimeric TASK‐1/TASK‐3 channels.
Functional links between motor and language systems
Authors: Pulvermüller Friedemann , Hauk Olaf , Nikulin Vadim V. , Ilmoniemi Risto J. 
Published: February 2005

AbstractTranscranial magnetic stimulation (TMS) was applied to motor areas in the left language‐dominant hemisphere while right‐handed human subjects made lexical decisions on words related to actions. Response times to words referring to leg actions (e.g. kick) were compared with those to words referring to movements involving the arms and hands (e.g. pick). TMS of hand and leg areas influenced the processing of arm and leg words differentially, as documented by a significant interaction of the factors Stimulation site and Word category. Arm area TMS led to faster arm than leg word responses and the reverse effect, faster lexical decisions on leg than arm words, was present when TMS was applied to leg areas. TMS‐related differences between word categories were not seen in control conditions, when TMS was applied to hand and leg areas in the right hemisphere and during sham stimulation. Our results show that the left hemispheric cortical systems for language and action are linked to each other in a category‐specific manner and that activation in motor and premotor areas can influence the processing of specific kinds of words semantically related to arm or leg actions. By demonstrating specific functional links between action and language systems during lexical processing, these results call into question modular theories of language and motor functions and provide evidence that the two systems interact in the processing of meaningful information about language and action.