According to the definition of satisfaction of Boolean dependencies, Theorem 15 is not true for Boolean dependencies with negation. (A positive Boolean dependency is built using the Boolean connectives ⋏, ⋎, and ↛; a ...
According to the definition of satisfaction of Boolean dependencies, Theorem 15 is not true for Boolean dependencies with negation. (A positive Boolean dependency is built using the Boolean connectives ⋏, ⋎, and ↛; a general Boolean dependency (with negation) may use also the Boolean connective ¬.) Actually, the definition of satisfaction is not meaningful for Boolean dependencies with negation, since many are never satisfied. We show how the definition of satisfaction should be changed in order to make Boolean dependencies with negation meaningful and correct the *** associate with each relation r a set α(r) of truth assignments, as follows. For each pair of distinct tuples of r, the set α(r) contains the truth assignment that maps an attribute A to true if the two tuples are equal on A, and to false if the two tuples have different values for A. A Boolean dependency σ is satisfied by a relation r if σ (i.e., the corresponding Boolean formula) satisfies every truth assignment of α(r).The original definition given in the paper is equivalent to having α(r) also include the truth assignment that is generated by pairs in which both tuples are really the same tuple of r, that is, to having α(r) also always include the truth assignment τ mapping all attributes to true. Under that definition, however, many Boolean dependencies with negation are never satisfied and, hence, are meaningless. More precisely, according to the original definition, a Boolean dependency is satisfied by
We consider M/G/l queues characterized by the total unfinished work (buffer content) U(t) in the system at time t. We allow the rate of the Poisson arrivals as well as the rate at which the server works, to depend on ...
A new concept, that of differential modelling, is introduced in this paper. The differential model of a system is one in which the response to a given input is equal to the differential change of the system response t...
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A new concept, that of differential modelling, is introduced in this paper. The differential model of a system is one in which the response to a given input is equal to the differential change of the system response that would result from a differential change of the input amplitude. The theory for determining optimum differential models of a given system is developed. As an example, the theory is applied to the analysis of an LNL system. The uses of differential modelling in system analysis which are illustrated by this example are discussed.
We present a model for a finite capacity, single-server M/G/1 queue in which customers, who would cause the system capacity of unfinished work to be exceeded, are lost. Problems are formulated for: (i) the stationary ...
We analyze a finite capacity M/G/1 queue in which an arrival that causes the system capacity of unfinished work to be exceeded, results in the loss of all jobs in the system. We sbudy the stationary density of unfinis...
In this paper we state results on the existence of Chandrasekhar equations for linear time invariant systems defined on Hilbert spaces. An important consequence of this is that the solution to the evolutional Riccati ...
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In this paper we state results on the existence of Chandrasekhar equations for linear time invariant systems defined on Hilbert spaces. An important consequence of this is that the solution to the evolutional Riccati equation is strongly differentiable in time and one can define a 'strong' solution of the Riccati differential equation. A discussion of the linear quadratic optimal control problem for hereditary differential systems is also included.
The UNIX ™ operating system Virtual Protocol Machine (VPM) is a package of software tools that allows a wide variety of link-level data communications protocols to be implemented efficiently in a high-level language. ...
The UNIX ™ operating system Virtual Protocol Machine (VPM) is a package of software tools that allows a wide variety of link-level data communications protocols to be implemented efficiently in a high-level language. The resulting protocol implementations are independent of the particular communications hardware, the host machine architecture, and the host operating system, and therefore can be ported easily from one hardware/software environment to another. An extension to VPM, the Common Synchronous Interface (CSI), provides similar benefits for the higher-level protocol software that runs in the UNIX system host. The implementations of VPM use Programmable Communications Devices (PCDs) to off load the link-level communications processing from the host CPU. A high-level language protocol description is translated by a protocol compiler that runs on the host machine. The resulting module is then loaded into the PCD and executed. The other components of VPM are a transparent protocol driver that allows user processes to interact directly with a link-level protocol implementation, a realtime trace capability to facilitate debugging, and several utility programs. VPM has been implemented on several different PCDs and several types of host computers. VPM-based protocol implementations can be ported with little or no change from one VPM implementation to another. VPM and CSI greatly reduce host system overhead while producing maximum communications throughput. A number of different higher-level protocols and their link-level counterparts have been implemented in the UNIX system using CSI and VPM; among them are X.25, 3270 emulation, a synchronous terminal interface, and a facility for remote job entry to IBM hosts.
A procedure of solution by quadratures for the strongly non-linear cylindrical deformations of shells and curved beams (“ring-like structures”) is discussed. Large strains, large rotations and material non-lineariti...
A procedure of solution by quadratures for the strongly non-linear cylindrical deformations of shells and curved beams (“ring-like structures”) is discussed. Large strains, large rotations and material non-linearities are involved. The procedure is then applied to obtain complete solutions to two problems: the deformations of the closed ring subjected to two opposing pulling forces and of the open ring subjected to combined pressure and tangential end load. Special features of the solutions as well as the merits of the several approximation models (from inextensional to membrane) are discussed in some detail. On discute à partir d'études antérieures [4], une procédure de résolution par quadratures pour les déformations cylindriques fortement non linéaires de coques et de poutres incurvées (“structures annulaires”). Ceci implique des déformations importantes, des rotations importantes et des non linéarités de matériaux. On applique ensuite la procédure pour obtenir des solutions complètes à deux problèmes: les deformations de l'anneau fermé soumis à deux forces de rappel opposées et de l'anneau ouvert soumis à une combinaison de pression et de charge tangente à l'extrémité. On discute en détail des caractéristiques particulières de solutions ainsi que les mérites de plusieurs modèles d'approximation (de l'inextensible à la membrane). Basierend auf frueheren Untersuchungen wird ein Loesungsver-fahren durch Quadraturen fuer stark nichtlineare zylindrische Verformungen von Schalen und gekruemmten Traegern (“ringartige Bauteile”) diskutiert. Grosse Dehnungen, starke Verdrehungen und Nichtlinearitaeten des Materials spielen eine Rolle, Das Verfahren wird zur Aufstellung der vollstaendigen Loesungen zweier Probleme benutzt: Die Deformationen eines geschlossenen Rings unter zwei entgegengesetzten Zugkraeften und eines offenen Rings unter kombinierter Druck- und tangentialer Endbelastung. Besondere Eigenschaften der Loesungen und die Vorzuege mehrerer Naeherungsmodelle werde
It is well known that certain graph‐theoretic extremal questions play a central role in the study of information network vulnerability. These extremal problems are special cases of the general question of realizabili...
It is well known that certain graph‐theoretic extremal questions play a central role in the study of information network vulnerability. These extremal problems are special cases of the general question of realizability of graph invariants. For example a ( p , Δ, δ, λ) graph is a graph having p ‐points, maximum degree Δ, minimum degree δ, and line‐connectivity λ. An arbitrary quadruple of integers ( a, b, c, d ) is called ( p , Δ, δ, γ) realizable if there is a ( p , Δ, δ, γ) graph with p = a , Δ = b , δ = c , and γ = d. Necessary and sufficient conditions for a quadruple to be ( p , Δ, δ, γ) realizable were recently given by the authors. In another manuscript they gave the solution to ( p , Δ, δ, k ) realizability, where k denotes the point connectivity. In this work we give necessary and sufficient conditions for ( p, q, k ), ( p, q , γ), and ( p, q , δ) realizability, where q denotes the number of lines of a graph.
A rational, systematic means of allocating air pollutant monitoring stations in an urban area is proposed in order to estimate the overall spatial averaged concentration. An urban area is divided into a certain number...
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A rational, systematic means of allocating air pollutant monitoring stations in an urban area is proposed in order to estimate the overall spatial averaged concentration. An urban area is divided into a certain number of subareas having nearly equal fluctuation of the pollution level. This division is made by solving an optimization problem of the spatial sample stratification in the Monte-Carlo random sampling method. In each subarea a representative point is selected in some defined sense as the location of a monitoring station. The procedure is applied to the design of the nitrogen oxides monitoring network in Kyoto airshed. The comparison between the proposed configuration and the actual one is presented.
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