The Computational Fluid Dynamics code Overflow includes as one of its solver options an algorithm which is a fairly small piece of code but which accounts for a significant portion of the total computational time. This paper studies some of the issues in accelerating the code by using a Graphics Processing Unit (GPU). The algorithm needs to be modified to be suitable for a GPU, and attention ne...

entropy coding, tree codes, adaptive coding This report presents an introduction to efficient adaptive compression using parameterized prefix codes. Advanced adaptive coding techniques can be quite complex because of the need to reliably estimate the probability of a large number of data symbols, each in a number of coding contexts, and then create the codes for each context, and finally code t...

These notes are an introduction to the RSA algorithm, and to the mathematics needed to understand it. The RSA algorithm — the name comes from the initials of its inventors, Rivest, Shamir, and Adleman — is the foundation of modern public key cryptography. It is used for electronic commerce and many other types of secure communication over the Internet. The RSA algorithm is based on a type of ma...

We study the problem of compressing a block of symbols (a block quantum state) emitted by a memoryless quantum Bernoulli source. We present a simple-to-implement quantum algorithm for projecting, with high probability, the block quantum state onto the typical subspace spanned by the leading eigenstates of its density matrix. We propose a fixed-rate quantum Shannon–Fano code to compress the proj...

We propose a scheme for the compression of tree structured intermediate code consisting of a sequence of trees specified by a regular tree grammar. The scheme is based on arithmetic coding, and the model that works in conjunction with the coder is automatically generated from the syntactical specification of the tree language. Experiments on data sets consisting of intermediate code trees yield...

• Huffman Code (optimal prefix-free code) • Shannon-Fano code • Shannon-Fano-Elias code • Arithmetic code (can handle a sequence of symbols) In general, the first three codes do not achieve the optimal rate H(X), and there are no immediate extensions of these codes to rate-optimal codes for a sequence of symbols. On the other hand, arithmetic coding is rate-optimal. However, all these schemes a...

In recent years, with emerging applications such as multimedia sensors networks, wireless low-power surveillance and mobile camera phones, the traditional video coding architecture in being challenged. In fact, these applications have different requirements than those of the broadcast video delivery systems: a low power consumption at the encoder side is essential. In this context, we propose a...

Unreachable code fragments in software, despite not having a negative impact on the functional behavior, can have a bad effect in other areas, such as code optimization or coverage-based code validation and certification. Especially the latter is important in industrial, safety critical environments, where detecting such dead code is a major goal to adjust the coverage of software tests. In the...

We introduce a generic framework for proof carrying code, developed and mechanically verified in Isabelle/HOL. The framework defines and proves sound a verification condition generator with minimal assumptions on the underlying programming language, safety policy, and safety logic. We demonstrate its usability for prototyping proof carrying code systems by instantiating it to a simple assembly ...

In this paper, we explore completely regular codes in the Hamming graphs and related graphs. Experimental evidence suggests that many completely regular codes have the property that the eigenvalues of the code are in arithmetic progression. In order to better understand these “arithmetic completely regular codes”, we focus on cartesian products of completely regular codes and products of their ...