Bottleneck analysis using queueing network models is an important technique for the performance analysis and capacity planning of computer and communication systems. Conventional single class as well as multiclass queueing network models use single mean values as input parameters. However, uncertainties and variabilities in service demands may exist in many models. This paper proposes to use ex...

Currently known basic anonymity techniques depend on identity veri cation. If veri cation of user identities is not possible due to the related management overhead or a general lack of information (e.g. on the Internet), an adversary can participate several times in a communication relationship and observe the honest users. In this paper we focus on the problem of providing anonymity without id...

Let z = (z1, z2, · · · , zn) be noncommutative free variables and t a formal parameter which commutes with z. Let k be a unital commutative ring of any characteristic and Ft(z) = z−Ht(z) with Ht(z) ∈ k[[t]]〈〈z〉〉 ×n and o(Ht(z)) ≥ 2. Note that Ft(z) can be viewed as a deformation of the formal map F (z) := z−Ht=1(z) when it makes sense. The inverse map Gt(z) of Ft(z) can always be written as Gt(...

The important distinction between parameterized specifications and specifications of parameterized programs has been originally pointed out in [12]. An important difference concerns the objects which the two kinds of parameterization allow one to reuse. A parameterized specification, “PSP”, e.g., of stacks parameterized by elements, Stack(El), allows one, under some conditions, to instantiate t...

The development of new hydrological simulation tools allows for the modelling of large hydrological catchments, with the aim of comprehensive management of the water resources, control of diffuse pollution processes, such as the fate of agricultural fertilizants and finally, with purposes of economical optimization of the crop yields as a function of the expected climate, the watershed characte...

Combination strategies are test methods that generate test cases based on input parameter models. This paper suggests a structured modeling method used to translate requirements expressed in a general format into an input parameter model suitable for combination strategies. This paper also describes results from two initial experiments exploring the efficiency and effectiveness of the modeling ...

In this paper, we investigate the notion of transformation modules as a structuring principle for the speciication of graph transformation systems which provide a collection of operations on graphs. Based on the notion of transformation units, a concept that allows to specify binary relations on graphs, a transformation module consists of a set of transformation units. To be able to distinguish...

In this work, we significantly improve the efficiency of non-malleable codes in the split state model, by constructing a code with codeword length |s|+O(k), where |s| is the length of the message, and k is the security parameter. This is a substantial improvement over previous constructions, both asymptotically and concretely. Our construction relies on a new primitive which we define and study...

We establish the inverse Lebedev expansion with respect to parameters and arguments of the modified Bessel functions for an arbitrary function from Hardy’s space H2,A, A> 0. This gives another version of the Fourier-integral-type theorem for the Lebedev transform. The result is generalized for a weighted Hardy space Ĥ2,A ≡ Ĥ2((−A,A);|Γ(1+Rez+iτ)|2dτ), 0 < A < 1, of analytic functions f(z),z = R...

Broadcast encryption is a type of encryption where the sender can choose a subset from a set of designated receivers on the fly and enable them to decrypt a ciphertext while simultaneously preventing any other party from doing so. The notion of private broadcast encryption extends the primitive to a setting where one wishes to thwart an attacker that additionally attempts to extract information...