Dual Antenna Receivers for High Data Rate Terminals

In this paper, dual antenna receiver architectures are studied including RAKE, chip-level linear equalizer, and their combination. The arithmetic complexity of single and dual antenna receiver methods is analyzed. Cost of such receivers when implemented with customized hardware or software on application-specific instruction set processors (ASIP) is estimated. The study shows that feasible dual antenna detection can be obtained with less than 70% additional costs. More flexible implementation supporting several standards can be obtained with software but it requires higher power consumption due to additional memory.     

Impact of 3G and beyond technology development and pricing on mobile data service provisioning,usage and diffusion

This study investigates the third generation mobile telecommunication systems (3G) diffusion challenges in the situation where large-scale mobile data service usage has not yet broken through. The paper first analyzes incumbent mobile operator business prospects in a large Western-European country. The results suggest that rollout of the most advanced available 3G technologies pay back through increased data service usage and revenues in the situation of declining voice revenues. In the main body of the study we discuss different pricing models and demonstrate that the flat rate pricing of data services, supplemented with certain conditions, supports the large-scale take-up of mobile data services. It boosts the usage of mobile data services and provides a competitive and sustainable business model for the operators and other market actors at the same time. Our modeling indicates furthermore, that flat rate model, combined with open access, gives better incentives to rollout high-speed mobile technologies to the rural areas, than the traffic-based charging.     

IEEE 802.11ac MIMO Transceiver Baseband Processing on a VLIW Processor

Wireless standards are evolving rapidly due to the exponential growth in the number of portable devices along with the applications with high data rate requirements. Adaptable software based signal processing implementations for these devices can make the deployment of the constantly evolving standards faster and less expensive. The flagship technology from the IEEE WLAN family, the IEEE 802.11ac, aims at achieving very high throughputs in local area connectivity scenarios. This article presents a software based implementation for the Multiple Input and Multiple Output (MIMO) transmitter and receiver baseband processing conforming to the IEEE 802.11ac standard which can achieve transmission bit rates beyond 1Gbps. This work focuses on the Physical layer frequency domain processing. Various configurations, including 2×2 and 4×4 MIMO are considered for the implementation. To utilize the available data and instruction level parallelism, a DSP core with vector extensions is selected as the implementation platform. Then, the feasibility of the presented software-based solution is assessed by studying the number of clock cycles and power consumption of the different scenarios implemented on this core. Such Software Defined Radio based approaches can potentially offer more flexibility, high energy efficiency, reduced design efforts and thus shorter time-to-market cycles in comparison with the conventional fixed-function hardware methods.     

Frequency-related effects in the optimization of coils for the magnetic stimulation of the nervous system

Magnetic stimulation of the nervous system is a non-invasive technique with a large number of applications in neurological diagnosis, brain research, and, recently, therapy. New applications require engineering modifications in order to decrease power consumption and coil heating. This can be accomplished by optimized coils with minimized resistance. In this study the influence of some frequency-related effects (skin and proximity effect) on the coil resistance will be discussed, together with the role played by wire shape, wire section, and twisting effect. The results show that the coil resistance increases with frequency. As an example, for a 20-mm2 circular wire section, the skin effect in the typical frequency range of magnetic stimulator devices (2-4 kHz) increases the coil resistance up to about 45% with respect to its dc value. Moreover, the influence of the frequency is lower for flat wire sections and reasonably small helix twist angle of the coil.     

Microbiological and chemical identification of antimicrobial drugs in kidney and muscle samples of bovine cattle and pigs

Microbiological and chemical identification of antimicrobial drug residues was attempted in 95 kidney and 76 muscle samples from 58 cattle, 36 pigs and one horse which had revealed kidneys positive to an inhibitor test. Information on pre-slaughter medication with one antimicrobial drug was available for 63% of the carcasses. Microbiological identification was performedbyagar diffusionusing 17 or 18combinationsof eight test bacteria, varying medium pH and three substances blocking the action of certain antimicrobials. Sampleactivity patterns compiled from inhibition zone diameters on test plates were compared with those obtained with standard antimicrobial solutions both visually and by locating the minimal sum of absolute pairwise differences over the tests. Chemical identification of residues was based on liquid chromatography. In kidney samples containing one microbiologicallyidentified antimicrobial the two methods gave fully consistent results with tetracyclines (15/15) and fluoroquinolenes (8/8). Preparation and storage of the kidney samples before chemical analyses appeared to influencethechemicalidentification of penicillin G. The results were consistent in 37 of the 41 samples stored without homogenization at - 70oC. The residue was identified by chemical means only in six and neither microbiologicallynorchemicallyinfour kidneysamples with information on pre-slaughter medication. The same residue as in the kidney samples was identifiable microbiologically in 41% of the muscle samples of the same carcasses. The results show that the microbiolo gical method is well suited for identification of antibiotic residues. They indicate further that an enhanced resolution with a reduced combination of plates is attainable.     

Simple-cell-like receptive fields maximize temporal coherence in natural video

Recently, statistical models of natural images have shown the emergence of several properties of the visual cortex. Most models have considered the nongaussian properties of static image patches, leading to sparse coding or independent component analysis. Here we consider the basic time dependencies of image sequences instead of their nongaussianity. We show that simple-cell-type receptive fields emerge when temporal response strength correlation is maximized for natural image sequences. Thus, temporal response strength correlation, which is a nonlinear measure of temporal coherence, provides an alternative to sparseness in modeling simple-cell receptive field properties. Our results also suggest an interpretation of simple cells in terms of invariant coding principles, which have previously been used to explain complex-cell receptive fields.     

The effect of inspection and repair on the size distributions of the weld imperfections in nuclear power plant pipes

The weld defects appearing in the pipes of the main steam system in a BWR power plant were studied. The effect of inspection rejection and repair on the imperfection size distribution was analysed. The size distributions before and after the inspection rejection as well as after the repair procedure were of the form a + b/x², where x is the imperfection size and a and b are coefficients. The portion of the rejected defects had the size dependence near to the form of the cumulative Gaussian function. The effect of repair on the initial size distribution had the form of the cumulative Poisson distribution.     

Microstructural development and evolution in liquid-phase sintered Fe-Cu alloys

An experimental study relating the scale and contiguity of liquid-phase sintered Fe-Cu alloys to sintering conditions has been conducted over a broad range of solid-phase volume fraction. It is found that the solid-phase contiguity attains a steady-state value at fairly short sintering times and that contiguity increases with increasing particle volume fraction, but is essentially independent of sintering temperature. Both the continuity and scale of microstructure are discussed in terms of concurrent particle coalescence and Ostwald ripening. It is found that values of the probability of particle coalescence after contact required to explain the contiguities observed are in reasonable agreement with theoretical predictions. However, comparison of observed contiguities with those predicted by recent studies is found to be unsatisfactory since the latter do not predict the steady-state contiguities observed. On the other hand, microstructural observations and measurements of coarsening-rate constants as a function of particle volume fraction indicate clearly that particle coalescence contributes significantly to the coarsening process at higher particle volume fractions.     

Formal restructuring functions for hierarchical data bases

Traditionally data restructuring of hierarchical data structures has been illustrated using examples in the context of the expressions of some transformation language. In this paper we define general and exact analysis and restructuring functions for hierarchical data bases. These functions describe restructuring of structural relationships among data structures, i.e. the construction of a target data base from a source data base is defined in detail. In fact, the analysis and restructuring functions define the tasks to be performed by the restructuring software at run time.