Like classical block codes, a locally repairable code also obeys the Singleton-type bound (we call a locally repairable code optimal if it achieves the Singleton-type bound). In the breakthrough work of [14], several classes of optimal locally repairable codes were constructed via subcodes of Reed-Solomon codes. Thus, the lengths of the codes given in [14] are upper bounded by the code alphabet...

In some cases,the Shannon code does not perform optimally. Consider a Bernoulli random variable X with parameter 0.0001. An optimal encoding requires only one bit to encode the value of X. The Shannon code would encode 0 by 1 bit and encode 1 by log 104 bits. This is good on average but bad in the worst case. We can also compare the Shannon code to the Huffman code. The Huffman code always has ...

Code optimisation in modern compilers is an accepted misnomer for performance im­ provement some of the time. The code that compilers generate is often significantly improved, but it is unlikely to produce optimal sequences of instructions; and if it does, it will not be possible to determine that they are indeed optimal. None of the existing approaches, or techniques for creating new optimisat...

In embedded computing, code size is very important for system cost and performance. In global scheduling for VLIW/EPIC style embedded processors, region-enlarging optimizations, especially tail duplication, are commonly used to exploit instruction level parallelism (ILP) to boost the performance. The code size increase due to such optimizations, however, raises serious concerns about the affect...

We describe our ongoing research within the EPICOpt project aimed at optimal and near-optimal code generation for explicitly parallel processors. On the one hand, this includes the application of techniques from the operations research domain to decrease the solver time for integer linear programming formulations of code generation problems. On the other hand, we want to investigate when and wh...

In this paper, we study ternary optimal formally self-dual codes. Bounds for the highest minimum weight are given for length up to 30 and examples of optimal formally self-dual codes are constructed. For some lengths, we have found formally self-dual codes which have a higher minimum weight than any self-dual code. It is also shown that any optimal formally self-dual [ 10,5,5] code is related t...

For optimization of real-world arch dams, it is unavoidable to consider two or more conflicting objectives. This paper employs two multi-objective differential evolution algorithms (MoDE) in combination of a parallel working MATLAB-APDL code to obtain a set of Pareto solutions for optimal shape of arch dams. Full dam-reservoir interaction subjected to seismic loading is considered. A benchmark ...