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7 A joint meeting with the SGML�Holland group is scheduled in spring
 J. of Automated Reasoning
, 1990
"... Abstract. The vision of a computerised assistant to mathematicians has existed since the inception of theorem proving systems. The Alcor system has been designed to investigate and explore how a mathematician might interact with such an assistant by providing an interface to Mizar and the Mizar Math ..."
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Cited by 9 (2 self)
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Abstract. The vision of a computerised assistant to mathematicians has existed since the inception of theorem proving systems. The Alcor system has been designed to investigate and explore how a mathematician might interact with such an assistant by providing an interface to Mizar and the Mizar Mathematical Library. Our current research focuses on the integration of searching and authoring while proving. In this paper we use a scenario to elaborate the nature of the interaction. We abstract from this two distinct types of searching and describe how the Alcor interface implements these with keyword and LSIbased search. Though Alcor is still in its early stages of development, there are clear implications for the general problem of integrating searching and authoring, as well as technical issues with Mizar.
Postmodern Software Design with NYAM: Not Yet Another Method
 Requirements Targeting Software and Systems Engineering
, 1998
"... . This paper presents a conceptual toolbox for software specification and design that contains techniques from structured and objectoriented specification and design methods. The toolbox is called TRADE (Toolkit for Requirements and Design Engineering). The TRADE tools are used in teaching informati ..."
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Cited by 7 (3 self)
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. This paper presents a conceptual toolbox for software specification and design that contains techniques from structured and objectoriented specification and design methods. The toolbox is called TRADE (Toolkit for Requirements and Design Engineering). The TRADE tools are used in teaching informatics students structured and objectoriented specification and design techniques, but the toolkit may be of use to practicing software engineers as well. The conceptual framework of TRADE distinguishes external system interactions from internal components. External interactions in turns are divided into external functions, behavior and communication. The paper shows that structured and OO analysis offer a small number of specification techniques for these aspects, most of which can be combined in a coherent software design specification. It is also shown that the essential difference between structured and objectoriented software design approaches lies in the separation of data storage, data ...
Lower Bounds on Messages and Rounds for Network Authentication Protocols
 1st ACM Conference on Computer and Communications Security
, 1993
"... Research in authentication protocols has largely focused on developing and analyzing protocols that are secure against certain types of attacks. There is little and only scattered discussion on protocol efficiency. This paper presents results on the lower bounds on the numbers of messages and rounds ..."
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Research in authentication protocols has largely focused on developing and analyzing protocols that are secure against certain types of attacks. There is little and only scattered discussion on protocol efficiency. This paper presents results on the lower bounds on the numbers of messages and rounds required for network authentication. For each proven lower bound, an authentication protocol achieving the bound is also given, thus proving that the bound is a tight bound if the given optimal protocol is secure. 1 Introduction Authentication is by definition a process to verify one's claim of identity. Since authentication is usually a prelude to further communication and computation, an authentication protocol often arranges that the protocol participants, once their identities are verified, agree upon an encryption key a temporary keyfor later use (e.g., within a user session). Thus an authentication protocol is sometimes also called a key distribution protocol. Current research...
Wider Still And Wider...  Resetting The Bounds Of Logic
, 1997
"... Modern logic is often defined in terms of specific formal languages, rules, and calculi. Such architectural decisions about a field form a pervasive implicit definition which determines professional practice  through the structure of textbooks, as well as the research agenda that determines 'inter ..."
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Cited by 5 (1 self)
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Modern logic is often defined in terms of specific formal languages, rules, and calculi. Such architectural decisions about a field form a pervasive implicit definition which determines professional practice  through the structure of textbooks, as well as the research agenda that determines 'interest', and hence acceptance and academic status. Such a practice may come to contain a lot of historical accident, or force of habit. Therefore, it seems worth thinking about the defining agenda of a field once in a while. In this brief essay, we explore alternative views of logic, locating the nature of the field in more abstract themes, concerns and attitudes. The new definition does not remove the need for the old agenda, but we advocate a shift in emphasis, toward greater generality and range of application. The outcome is a conception of logic as a broad methodological stance, looking for invariants in (information) structures and processes. to appear in A. Varzi, ed. "The European Revie...
An index formula for simple graphs
, 2012
"... Abstract. We prove that any odd dimensional geometric graph G = (V, E) has zero curvature everywhere. To do so, we prove that for every injective function f on the vertex set V of a simple graph the index formula 1 [1 − 2 χ(S(x))/2 − χ(Bf (x))] = (if (x) + i−f (x))/2 = jf (x) holds, where if (x) is ..."
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Abstract. We prove that any odd dimensional geometric graph G = (V, E) has zero curvature everywhere. To do so, we prove that for every injective function f on the vertex set V of a simple graph the index formula 1 [1 − 2 χ(S(x))/2 − χ(Bf (x))] = (if (x) + i−f (x))/2 = jf (x) holds, where if (x) is a discrete analogue of the index of the gradient vector field ∇f and where Bf (x) is a graph defined by G and f. The PoincaréHopf formula ∑ x jf (x) = χ(G) allows so to express the Euler characteristic χ(G) of G in terms of smaller dimensional graphs defined by the unit sphere S(x) and the ”hypersurface graphs ” Bf (x). For odd dimensional geometric graphs, Bf (x) is a geometric graph of dimension dim(G)−2 and jf (x) = −χ(Bf (x))/2 = 0 implying χ(G) = 0 and zero curvature K(x) = 0 for all x. For even dimensional geometric graphs, the formula becomes jf (x) = 1−χ(Bf (x))/2 and allows with PoincaréHopf to write the Euler characteristic of G as a sum of the Euler characteristic of smaller dimensional graphs. The same integral geometric index formula also is valid for compact Riemannian manifolds M if f is a Morse function, S(x) is a sufficiently small geodesic sphere around x and Bf (x) = S(x) ∩ {y  f(y) = f(x)}. 1.
Proofs and Refutations, and Z3
"... Z3 [3] is a stateoftheart Satisfiability Modulo Theories (SMT) solver freely available from Microsoft Research. It solves the decision problem for quantifierfree formulas with respect to combinations of theories, such as arithmetic, bitvectors, arrays, and uninterpreted functions. Z3 is used in ..."
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Z3 [3] is a stateoftheart Satisfiability Modulo Theories (SMT) solver freely available from Microsoft Research. It solves the decision problem for quantifierfree formulas with respect to combinations of theories, such as arithmetic, bitvectors, arrays, and uninterpreted functions. Z3 is used in various software analysis and testcase generation projects at Microsoft Research and elsewhere. The requirements from the userbase range from establishing validity, dually unsatisfiability, of firstorder formulas; to identify invalid, dually satisfiable, formulas. In both cases, there is often a need for more than just a yes/no answer from the prover. A model can exhibit why an invalid formula is not provable, and a proofobject can certify the validity of a formula. This paper describes the proofproducing internals of Z3. We also briefly introduce the modelproducing facilities. We emphasize two features that can be of general interest: (1) we introduce a notion of implicit quotation to avoid introducing auxiliary variables, it simplifies the creation of proof objects considerably; (2) we produce natural deduction style proofs to facilitate modular proof reconstruction.
Apallic syndrome is not apallic: Is vegetative state vegetative? Neuropsychological Rehabilitation 2005
"... Initial conceptualisation about the nature of vegetative state (VS) assumed at least temporary loss of the entire cortical functioning. Since a broad range of stimulusrelated cortical activations was demonstrated in VS patients, this simplified idea is not tenable any longer, but no alternative con ..."
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Initial conceptualisation about the nature of vegetative state (VS) assumed at least temporary loss of the entire cortical functioning. Since a broad range of stimulusrelated cortical activations was demonstrated in VS patients, this simplified idea is not tenable any longer, but no alternative concept emerges instead. Two recent hypotheses, empirically testable and well grounded, could fill this vacuum: (1) In VS, isolated cortical areas may work, but their integration into a distributed network is lacking. (2) In VS, complex stimulus processing is limited to primary sensory and motor areas; the coordination between them and the secondary and tertiary areas is lacking. To test these hypotheses, we estimated the frequency of occurrence of late eventrelated potential components P3 and N400, presumably indicating activity of complex distributed networks including highlevel sensory and associative areas. Both components occurred in VS with abovechance frequencies, but less frequently than in two control groups. Besides these frequent normal brain activations, some VS patients exhibit highly significant but abnormal activations, whose functional meaning remains unclear. A methodological analysis leads to the conclusion that any neurophysiological assessment of VS patients is biased toward under, rather than overestimation, of their remaining information processing abilities.
The Calculator and Computer Precalculus Project (C 2 PC): What have we learned in Ten Years
 In
, 1994
"... We have a philosophy about incorporating technology into instruction that is grounded in the experience gained from our ..."
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Cited by 4 (3 self)
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We have a philosophy about incorporating technology into instruction that is grounded in the experience gained from our
What Do Argument Diagrams Tell Us About Students’ Aptitude Or Experience? A Statistical Analysis In An Ill Defined Domain�
"... Abstract. In illdefined domains, argumentation skills are essential in order to define problems and to present, justify, and evaluate solutions. In welldefined domains there exist accepted methods of characterizing student arguments as good or bad. This is not always possible in illdefined domain ..."
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Cited by 4 (1 self)
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Abstract. In illdefined domains, argumentation skills are essential in order to define problems and to present, justify, and evaluate solutions. In welldefined domains there exist accepted methods of characterizing student arguments as good or bad. This is not always possible in illdefined domains, where competing arguments are often acceptable. In this paper, we use a set of statistical analysis methods to investigate whether, despite the lack of an “ideal solution,”, studentproduced argument diagrams can be diagnostic in that they can be used to reliably classify students into novices and experts or high and low aptitude. Our analysis, based on data collected during three studies with the LARGO ITS, suggests that indeed, argument graphs created by different student populations differ considerably, particularly with respect to the completeness and “connectedness ” of graphs, and can thus potentially be used to adapt the system to a particular student’s needs.
Formalizing the UML in a Systems Engineering Approach
 Proceedings Second ECOOP Workshop on Precise Behavioral Semantics (with an Emphasis on OO Business Specifications), pages 254266. Technische Universitat Munchen, TUMI9813
, 1998
"... This discussion note argues for embedding any formalization of semiformal notations in a methodology. I present a methodological framework for software specification based on systems engineering and show how the UML fits into this framework. Next, an essential modeling approach to formalizing the UM ..."
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This discussion note argues for embedding any formalization of semiformal notations in a methodology. I present a methodological framework for software specification based on systems engineering and show how the UML fits into this framework. Next, an essential modeling approach to formalizing the UML within this framework is argued. Finally, a transition system semantics for the UML is discussed, that fits this semantics approach. No formal details are given, but references are given to places where these can be found. 1 Formalism and Method Current research of several research groups is oriented to formalizing diagrammatic specification techniques [5, 9, 20, 37]. There is a close connection between the intended semantics of a notation for system specifications on the one hand and the intended method for system specification on the other. For example, if the method distinguishes a specification level from an implementation (programming language) level, as is done in Syntropy [6], then...