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In this paper we evaluate the use of parallel interleavers for user separation in coded IDMA systems. The parallel interleavers have previously been evaluated for uncoded systems, and we here present extended results for the coded case. The new results are important for real systems, as they will most likely use performance enhancing channel coding. The parallel interleavers are designed to remove
The fast correlation attack is a general cryptanalytic attack directed at stream ciphers and is related to the decoding of low-density parity-check (LDPC) codes. In this paper, we improve the message passing algorithm by exploiting the fact that the sum of an arbitrary number of initial state variables, called a fixed point, can be written as the sum of only a few other variables. This will result
We consider the problem of detecting exploits based on return-oriented programming. In contrast to previous works we investigate to which extent we can detect ROP payloads by only analysing streaming data, i.e., we do not assume any modifications to the target machine, its kernel or its libraries. Neither do we attempt to execute any potentially malicious code in order to determine if it is an att
We present a model for supporting scoping decisions that is based on an analysis of the ROI for a given feature. Employing a ROI threshold value for making scoping decisions, the utility of the model was investigated using data from a single large project and identified a group of outlying features responsible for a disproportionate wasted investment. These initial results are promising and indica
Test managers have to repeatedly select test cases for test activities during evolution of large software systems. Researchers have widely studied automated test scoping, but have not fully investigated decision support with human interaction. We previously proposed the introduction of visual analytics for this purpose. Aim: In this empirical study we investigate how to design such decision suppor
It is well known that fast correlation attacks can be very efficient if the feedback polynomial is of low weight. These feedback polynomials can be considered weak in the context of stream ciphers. This paper generalizes the class of weak feedback polynomials into polynomials were taps are located in several groups, possibly far apart. Low weight feedback polynomials are thus a special case of thi
Two gated ring oscillators (GROs) act as the delay lines in an improved Vernier time-to-digital converter (TDC), where the already small quantization noise of the standard Vernier TDC is further first-order shaped by the GRO operation. The TDC has been implemented in a 90nm CMOS process and consumes 3mA from 1.2V when operating at 25MHz. The native Vernier resolution of the TDC is 5.8ps, while the
Successful development of software systems involves efficient navigation among software artifacts. However, as artifacts continuously are produced and modified, engineers are typically plagued by challenging information landscapes. One state-of-practice approach to structure information is to establish trace links between artifacts, a practice that is also enforced by several development standards
Optimization techniques always play an important role in designing high-performance wireless systems. This presented thesis studies a selected set of optimization problems for different kinds of wireless networks, making use of mathematical programming techniques to find optimal solutions and of efficient heuristics to find near-optimal solutions. The basic contribution of the thesis consists in a
Given a weighted directed graph where some arcs can fail while others are reliable, we aim to compute a shortest pair of failure-disjoint paths. If a reliable arc is used by both paths, its cost is counted only once. We present a polynomial time algorithm to solve the problem.
To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. A promising way to increase the amount of available spectrum is to utilize fre
We derive the interarrival distribution of a workload input process which is a variation of the infinite source Poisson process for packet traffic. It accounts for long-range dependence and self-similarity exhibited by real traces in the Internet. The packet generation process is compound Poisson over each session which has a heavy tailed distribution. Considering the dependence induced by the wor
Maturity models are widely used in process improvement. The users of a maturity model should be confident that the weak points of the assessed processes can be found, and that the most valuable changes are introduced. Therefore, the evaluation of maturity models is an important activity. In this paper, a mapping study of the literature on the evaluation of maturity models is presented. Two databas
In this study, the authors investigate the resistance of Boolean functions against fast algebraic attacks and deduce a bound between fast algebraic immunity and higher-order non-linearity (it is the first time that a bound between these two cryptographic criteria is given). The authors then show that the fast algebraic immunity of the following two classes of Boolean functions is not good: (a) The
Abstract in Undetermined[Context and motivation] There is considerable flexibility in requirements specifications (both functional and non-functional), as well as in the features of available OSS components. This allows a collaborative matching and negotiation process between stakeholders such as: customers, software contractors and OSS communities, regarding desired requirements versus available
