Sökresultat

In this paper, we study the problem of joint permutor analysis and design for J-dimensional multiple turbo codes with J constituent encoders, J>2. The concept of summary distance is extended to multiple permutors of size N and used as the design metric. Using the sphere-packing concept, we prove that the minimum length-2 summary distance (spread) Dmin,2 is asymptoticly upper-bounded by O(N J-1/J).

Recent research and practice have led to the development of relatively complex methods for inquiry which can be applied by human analysts wishing to investigate an organizational problem-space. However, it has appeared until recently that use of these methods could not be supported by software tools, since the limitations of traditional mathematical algorithms constrained their development. In con

Fast and reliable time and frequency synchronization is crucial for packet-based orthogonal frequency division multiplex (OFDM) systems. In this paper we compare and analyze preambles for OFDM systems based on repeated OFDM data symbols or repeated short pseudonoise sequences (PN-sequences). We make an analytical evaluation for AWGN channels and simulate the performance in oneand two-tap Rayleigh

Biodegradation is becoming an attractive mode of operation for eliminating toxic chemicals released from industrial processes or already present in the environment. One needs, however, not only to identify organisms capable of degrading such chemicals, but also to address the issue of whether these chemicals, after being degraded, will be toxic to the degrading organisms if present in high concent

Welding fumes include agglomerated particles built up of primary nanoparticles. Particles inhaled through the nose will to some extent be deposited in the protein-rich nasal mucosa, and a protein corona will be formed around the particles. The aim was to identify the protein corona formed between nasal lavage proteins and four types of particles with different parameters. Two of the particles were

As the presence of English in Europe continues to grow, there is a mounting interest in the position of national languages among European institutions, societies, and people. Swedish, like many national languages in Europe and throughout the world, is in an awkward position. It is at the same time a strong national language with the potential to dominate other languages within national borders and

Abstract in UndeterminedBackground: The current management guidelines for pediatric mild head injury (MHI) liberally recommend computed tomography (CT) and frequent admission. Serum protein S100B, currently used in management of adult head injury, has recently shown potential for reducing unnecessary CT scans after pediatric mild head injury. Capillary sampling in children is commonly used when ve

A procedure to obtain future local precipitation characteristics focused on extreme conditions has been developed based on a weather generator. The method involves six major steps: (1) the weather generator was calibrated using observed daily precipitation at 220 Swedish stations during 1961–2004; (2) present and future daily precipitation characteristics for the Swedish stations from two global c

A full-rank IC x n matrix G(D) over the rational functions F(D) generates a rate R = k/n convolutional code C. G(D) is minimal if it can be realized with as few memory elements as any encoder for C, and G(D) is canonical if it has a minimal realization in controller canonical form. We show that G(D) is minimal if and only if for all rational input sequences p1 (D), the span of U (D) G (D) covers t

Requirements Engineering and Software Testing are mature areas and have seen a lot of research. Nevertheless, their interactions have been sparsely explored beyond the concept of traceability. To fill this gap we propose a definition of requirements engineering and software test (REST) alignment, a taxonomy that characterizes the methods linking the respective areas, and a process to assess alignm

Time-domain maximum-likelihood (ML) estimators of time and frequency offsets are derived for three orthogonal frequency division multiplexing (OFDM) signal models: a pulse-shaped one-shot OFDM signal, a stream of multiple OFDM signals and an OFDM signal in a dispersive channel environment. We then develop structures to simplify their implementation. Simulation results show the relative performance

Popular Abstract in Swedish Denna avhandling ger en introduktion till laser-plasma acceleratorer, vilket även utgör ämnet för de vetenskapliga artiklar som ingår i avhandlingen. Det är en ny typ av acceleratorer som utnyttjar mycket kraftfulla lasrar för att accelerera elektroner och protoner. Partikelacceleratorer används för att ge partiklar hög rörelseenergi, vilket kan utnyttjas för många olikThis thesis presents experimental results related to laser plasma accelerators. These rely on very different principles from conventional particle accelerators. They are able to accelerate particles over a very short distance and produce synchrotron x-rays at the same time, potentially providing a compact particle accelerator and x-ray source for many future applications. The laser pulses used in

The visual system in animals and humans consists of a number of information processing units that are here called visual routines. These routines are specialized in handling different cognitive tasks, for example, object recognition, motion, stereo, color, texture, and optic flow. together, these routines contribute to the internal representation of the visual world. On the top of this network of

This thesis deals with physical limitations on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. The result states that for a given volume, there is only a limited amount of scattering and absorption available i