This letter proposes an approximate waterfill power loading scheme using limited feedback in orthogonal frequency division multiplexing (OFDM) systems. The proposed technique achieves nearly the capacity of optimal waterfill power loading, while significantly reducing feedback by using order information for the subcarrier channel gains. Furthermore, the proposed power loading technique can circumvent the practical shortcomings of previous limited feedback power loading techniques by simply exploiting order mapping and interpolation. The advantages are particularly visible at low SNR or for many subcarriers, both of which will be very common in emerging wireless broadband OFDM standards.

The novel pulses, which not only meet the power spectral mask of the Federal Communications Commission (FCC) but also preserve orthonormality at the correlation receiver, have been proposed by Kim for high data rate communications in indoor ultra-wideband (UWB) systems. The proposed multiple orthonormal pulses comply with the FCC spectral mask without additional frequency shifting or bandpass filters, and furthermore, provide enhanced bit-error rate (BER) performance, compared with a well-known Gaussian monocycle and modified Hermite pulses. This paper analyzes the impact of the proposed pulses' properties, such as their auto- and cross-correlations, on the correlation receiver of the UWB system based on the pulse position modulation. The performance of the proposed pulses are compared with different waveforms under various conditions, such as multipath fading, timing mismatch, and multiuser interference. We also discuss a modulation scheme using the multiple orthogonal pulses to achieve the enhancement of data rate and the impact of the correlation characteristics of the proposed waveforms on the BER performance. Simulation results demonstrate the effectiveness of the proposed orthonormal pulses in various conditions, comparing with different waveforms

The ability to estimate cardiac output by thermodilution, as initially described by Fegler (1954), was an important step in hemodynamic monitoring. However, the usefulness of this procedure has been hampered by the difficulty in filtering the thermal noise from the thermodilution signal in the pulmonary artery. As a result, current procedures are limited to intermittent measurements with large-bolus injections that produce an acceptable signal-to-noise ratio (SNR). This paper presents one approach to solving this problem using the nonlinear mapping ability of artificial neural networks (ANN). It is shown that the cardiac output estimated by the ANN significantly improves the classical method of computing cardiac output with small-injectates using the Stewart-Hamilton equation and are within clinically acceptable limits in comparison to the "gold standard".

Perfect quality represents 100% conformance to specifications. Complex systems make it difficult and expensive to assure conformance to specifications by post-production testing alone. As a result, quality assurance processes are moving upstream in the life-cycle, i.e. statistical process control and design for manufacturability. These processes try to avoid defects or make it easier to detect defects. In software systems, this move to upstream processes for quality control is still in its early stages. As with more traditional manufacturing systems, maturity of the software design and development process will dramatically reduce the cost of attaining conformance to specifications. Even so, it is difficult to imagine a "bug-free" complex software system. Downstream processes will continue to play an important part in the efforts to achieve defect-free software. This paper presents results of a survey which used the defect detection tool Purify to examine off-the-shelf software products in order to show that software errors continue to escape testing and threaten field failures. Errors detected are compiled and presented. All data were collected on C and C++ programs running in a UNIX operating system environment.

The study of the relation between faults and its syndromes in the signature analysis of computer hardware testing is presented. When an incorrect signature is observed, it is caused by one of many possible error sequences that contains errors at different locations. The characteristics of the error distributions are identified for greater fault coverage. Formal analysis is presented in conjunction with the subject of error-control code. The results provide insights into the use of deterministic test patterns in signature analysis.>

A fault diagnostic algorithm which makes use of the information from a faulty signature is presented. The idea is to search the likely fault locations before the tests are performed. The method reduces the number of tests required to diagnose the faults with the probability of error aliasing. Such probability is always smaller than that of error detection in signature analysis. When matching tests are difficult or impossible, the method provides an estimate of where errors that caused the incorrect signature might have occurred.>

Some aspects of a special multimodality and adaptivity in a two-person game, renju (a Japanese alignment game on a board) are presented. It is argued that such a renju multimodality will surely be a new basis of ideas and understanding of adaptive processes in artificial inttelligence requiring multimodal optimum search. The necessary concepts are developed, such as distance between any two points, four directions, string, jumstring, costring, dead (jum)string, and criterion function of a placed stone (piece or chip) on a renju board. The essential aspects of renju multimodality and adaptivity studied here are as follows: possible values of the criterion function, realized number of the highest peak (lowest valley) formed by the criterion function within a game, height of maximum peak versus the issue of the game, possible number of the highest peak (lowest valley), illustration of the criterion function, developing processes of peak and valley, adaptive mobility of the optimum point, and practical appearance of the multimodality of renju problems.

The purpose of this correspondence is to apply the results of Patterson to a pattern classification problem which has been considered frequently in the literature and to show that a convergence result is obtained which is as strong as any presented to date.