Free Surface Test (2D).. Our free surface Stokes test case is a fluid disk of radius r = 0.75 centred at the origin, with density ρ = 1 and viscosity μ = 0.1, computed over a timestep ∆t = 1 . For simplicity of presentation, we describe the final velocity field in terms of a stream function,ψ , where the velocity field can be derived as uf inal = ∇ ×ψ . This also guarantees that the velocity fi...

Sfinks is a shift register based stream cipher designed for hardware implementation. The initialisation state update function is different from the state update function used for keystream generation. We demonstrate state convergence during the initialisation process, even though the individual components used in the initialisation are one-to-one. However, the combination of these components is...

The finite element solution of a generalized Stokes system in terms of the flow variables stream function and vorticity is studied. This system results from a time discretization of the time-dependent Stokes system in stream function-vorticity formulation, or yet by the application of the characteristics method to solve the Navier-Stokes equations in the same representation. Numerical results p...

Ratio pulse arithmetic represents a signal with a random pulse stream and its value is defined as the ratio of ones and zeroes in its random pulse stream. We propose circuits for the exponential function and subtraction, and explain how to implement a radial basis function(RBF) network. We applied the RBF network to a classifier example. Simulation results show that its performance is comparabl...

Stream ciphers are fast cryptographic primitives to provide confidentiality of electronically transmitted data. They can be very suitable in environments with restricted resources, such as mobile devices or embedded systems. Practical examples are cell phones, RFID transponders, smart cards or devices in sensor networks. Besides efficiency, security is the most important property of a stream ci...

• Standard stream model: m elements from universe of size n, come one by one. Goal: compute a function of stream. Constraints: (1) Limited space (working memory), sublinear in n and m. (2) Access data sequentially. (3) Process each element quickly. • Graph stream: elements of the stream are edges. Let n be the number of vertices. We have m = O(n 2). To be able to handle interesting functions, w...

RC4-Hash is a variable digest length cryptographic hash function based on the design of the RC4 stream cipher. In this paper, we show that RC4-Hash is not collision resistant. Collisions for any digest length can be found with an expected effort of less than 2 compression function evaluations. This is extended to multicollisions for RC4-Hash. Finding a set of 2 colliding messages has an expecte...

This review focuses on some of the roles of macroinvertebrate functional groups, i.e. grazers, shredders, gatherers, filterers, and predators, in stream-ecosystem processes. Many stream-dwelling insects exploit the physical characteristics of streams to obtain their foods. As consumers at intermediate trophic levels, macroinvertebrates are influenced by both bottom-up and top-down forces in str...