The application of telepresence in medicine

Telemedicine is a wide ranging subject which encompasses teleconsultation, electronic patient records, continuing medical education and public health information systems. Telemedicine will impact every aspect of health care delivery from remote clinical analysis and consultation between experts based in specialist hospitals, to teleconsultation as a substitute for physical referral between the GP and a hospital, and ultimately the remote delivery of medical monitoring and care into the h ome. Telepresence, where remote human expertise is transported by communications networks to a remote location, has its own unique place within the spectrum of telemedicine applications. This paper describes some of those applications of medical telepresence into which BT have been researching with various clinical partners.     

Inactivation of Nisin by Glutathione in Fresh Meat

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to determine the fate of nisin in meat products. Nisin in 0.02N HCl was added to fresh and cooked meat and meat juice and samples were stored at 4 °C overnight. Residual nisin solutions and meat juice and meat extract supernatants were analyzed for antimicrobial activity and for nisin. Nisin was recovered from cooked meat extract and cooked meat juice; however, only nisin bound to a food component was detected in fresh meat extract. Mass spectra for raw meat and juice showed a signal 307 Da greater than the mass of nisin. Results indicated that nisin was likely inactivated in raw meat by an enzymatic reaction with glutathione.     

Vector quantization by deterministic annealing

A deterministic annealing approach is suggested to search for the optimal vector quantizer given a set of training data. The problem is reformulated within a probabilistic framework. No prior knowledge is assumed on the source density, and the principle of maximum entropy is used to obtain the association probabilities at a given average distortion. The corresponding Lagrange multiplier is inversely related to the `temperature' and is used to control the annealing process. In this process, as the temperature is lowered, the system undergoes a sequence of phase transitions when existing clusters split naturally, without use of heuristics. The resulting codebook is independent of the codebook used to initialize the iterations     

Speed and area tradeoffs in cluster-based FPGA architectures

One way to reduce the delay and area of field-programmable gate arrays (FPGAs) is to employ logic-cluster-based architectures, where a logic cluster is a group of logic elements connected with high-speed local interconnections. In this paper, we empirically evaluate FPGA architectures with logic clusters ranging in size from 1 to 20, and show that compared to architectures with size 1 clusters, architectures with size 8 clusters have 23% less delay (30% faster clock speed) and require 14% less area. We also show that FPGA architectures with large cluster sizes can significantly reduce design compile time-an increasingly important concern as the logic capacity of FPGA's rises. For example, an architecture that uses size 20 clusters requires seven times less compile time than an architecture with size 1 clusters     

Electrical Percolation Behavior in Silver Nanowire–Polystyrene Composites: Simulation and Experiment

The design and preparation of isotropic silver nanowire‐polystyrene composites is described, in which the nanowires have finite L/D (< 35) and narrow L/D distribution. These model composites allow the L/D dependence of the electrical percolation threshold, ?_c, to be isolated for finite‐L/D particles. Experimental ?_c values decrease with increasing L/D, as predicted qualitatively by analytical percolation models. However, quantitative agreement between experimental data and both soft‐core and core–shell analytical models is not achieved, because both models are strictly accurate only in the infinite‐L/D limit. To address this analytical limitation, a soft‐core simulation method to calculate ?_c and network conductivity for cylinders with finite L/D are developed. Our simulated ?_c results agree strongly with our experimental data, suggesting i) that the infinite‐aspect‐ratio assumption cannot safely be made for experimental networks of particles with L/D < 35 and ii) in predicting ?_c, the soft‐core model makes a less significant assumption than the infinite‐L/D models do. The demonstrated capability of the simulations to predict ?_c in the finite‐L/D regime will allow researchers to optimize the electrical properties of polymer nanocomposites of finite‐L/D particles.     

A dielectric-free superconducting coaxial cable

The theoretical properties of a dielectric-free superconducting coaxial cable with a magnetically levitated inner conductor are studied. It is found that at 100 GHz the intrinsic attenuation along such a cable is on the order of a 0.1 dB per kilometer. Furthermore, for a given cable, the loss is proportional to the square of the frequency. This low loss, coupled with a generous signal to noise ratio (≈80 dB at 100-GHz bandwidth), provides bit rates of 100 Gb/s over 600 km. At 10 Gb/s the distance increases to over 60000 km. Such a high-bandwidth, extremely-low-loss electronic transmission medium might be of interest for very-long distance repeaterless communications. In addition, since efficient means of tapping coaxial media already exist, local area network applications with an excess of 10⁴ users could be supported. The two properties of superconductors central to this application are very low intrinsic loss and expulsion of magnetic flux. Low loss allows high-bandwidth dispersionless transmission, and magnetic flux expulsion permits magnetic support of the inner conductor, thereby avoiding the large dielectric losses associated with any support material     

Performance Analysis of Downlink W-CDMA Systems in Weibull and Lognormal Fading Channels Using Chaotic Codes

In this paper, a subspace based blind channel estimation scheme for downlink W-CDMA systems using chaotic codes under Weibull and Lognormal fading channel conditions is proposed and compared with W-CDMA system using PN codes. The algorithm provides estimates of multiuser channels by exploiting the structural information of the data output. The subspace of the (data + noise) matrix contains sufficient information for unique determination of channels and, hence, the signature waveforms and signal constellations. The proposed channel estimation algorithm is also implemented for multiuser—orthogonal frequency division multiplexing (OFDM) system. Performance measures like bit error rate (BER) and root mean square error (RMSE) are plotted for Weibull and Lognormal fading channels. Signal constellations under Weibull and Lognormal channels are also plotted. Analytical and Simulation results for BER and RMSE are compared for W-CDMA system using PN codes and chaotic codes. Simulation results show that, chaos-based W-CDMA outperforms the PN-based W-CDMA in terms BER and RMSE. Simulation results of multiuser-OFDM system shows that performance is further improved when compared to the W-CDMA system.     

Book Reviews: Extensible Middleware

A review of Distributed Infrastructure Support for Electronic Commerce Applications by Hans-Arno Jacobsen.     

Zero-Error Source&#8211;Channel Coding With Side Information

This correspondence presents a novel application of the theta function defined by Lovasz. The problem of coding for transmission of a source through a channel without error when the receiver has side information about the source is analyzed. Using properties of the Lovasz theta function, it is shown that separate source and channel coding is asymptotically suboptimal in general. By contrast, in the case of vanishingly small probability of error, separate source and channel coding is known to be asymptotically optimal. For the zero-error case, it is further shown that the joint coding gain can in fact be unbounded. Since separate coding simplifies code design and use, conditions on sources and channels for the optimality of separate coding are also derived