Computer-Oriented Formulation of Transition-Rate Matrices via Kronecker Algebra

This paper formulates the differential equations typical of a Markov problem in system-reliability theory in a systematic way in order to generate computer-oriented procedures. The coefficient matrix of these equations (the transition rate matrix) can be obtained for the whole system through algebraic operations on component transition-rate matrices. Such algebraic operations are performed according to the rules of Kronecker Algebra. We consider system reliability and availability with stress dependence and maintenance policies. Theorems are given for constructing the system matrix in four cases: * Reliability and availability with on-line multiple or single maintenance. * Reliability and availability with system-state dependent failure rates. * Reliabilityand availability with standby components. * Off-line maintainability. The results are expres § ed in algebraic terms and as a consequence their implementation by a computer program is straightforward. We also obtain information about the structure of the matrices involved. Such information can considerably improve computational efficiency of the computer codes because it allows introducing special ideas and techniques developed for large-system analysis such as sparsity, decomposition, and tearing.     

Multilevel sequences with good autocorrelation properties

A computer-oriented method for designing multilevel sequences with low autocorrelation sidelobes is discussed. The multilevel sequences with pulse-like autocorrelation function are generated iteratively, starting with a sequence having relatively low sidelobes in its autocorrelation function. The method can be used to generate a sequence of any desired length     

Binary sequences with good correlation properties

A computer-oriented method for designing binary sequences with low autocorrelation sidelobes is discussed. It is shown that this method yields binary codes that are only marginally worse than known better codes. The technique described is quite general and can be applied to other signal-design problems.     

Algorithm applicable to logic-circuit synthesis

A method is described which, in its exhaustive application, synthetises logic functions by means of any chosen gates or subsystems. The method employs Boolean matrices and is computer-oriented. The algorithm in its simplest form does not afford optimisation, except on a comprehensive-search basis. In this respect, the procedure is similar to those of Roth et al. and Ashenhurst, and embodies case of implementation together with the ability to handle multiple-output problems.     

Steady-state analysis of piecewise-linear systems with periodic inputs

A specific form of a recently proposed algorithm is derived for the rapid determination of the steady-state response of large classes of piecewise-linear systems subjected to periodic inputs. It can be directly incorporated at marginal cost into a computer-oriented state space approach for generating the time domain response of such systems. The algorithm has been successfully applied to several circuits.     

Novel MIC bipolar frequency doublers having high gain, widebandwidth and good spectral performance

Techniques for the design of high efficiency bipolar microwave frequency multipliers having wideband performance, high conversion gain and good spectral properties are presented. Experimental conversion gains of up to 7 dB have been attained for narrow bandwidths (≈8%) and approximately 0 dB for wideband designs (40%) at C band. Corresponding fundamental and 3rd harmonic rejections are greater than 40 dBc. Extensive modeling and computer-oriented design have been employed utilizing harmonic balance     

The Correlation Method for Computer-Aided Statistical Analysis

Computer-aided statistical analysis of electronic circuits, designed to predict the effects of component-part variability on circuit performance, provides extremely useful assistance in performing a circuit design. The correlation method, a new computer-oriented technique of statistical analysis, provides precise estimates of performance variability, high speed of computation, and the computation of the distribution laws of circuit performance characteristics at a generic time instant. Thus, the quantitative characteristics of reliability can be predicted as functions of time.     

Fiber to the Home/Fiber to the Premises: What, Where, and When?

After conquering the core and metropolitan networks, fiber is now penetrating into the access domain. Its low loss and huge bandwidth enable the delivery of any current and foreseeable set of broadband services, and also make it a nice match to the wireless link to the end user. Cost effectiveness is a key issue, and will be decisive for the network topology choices. Point-to-point may be the most cost-effective for short-reach access, whereas point-to-multipoint may be the most interesting at medium- to long-reach access, or when line terminations in the local exchange become a key issue. A number of optical techniques being deployed for shared-fiber multiple access are discussed, based on time slot multiplexing, frequency slot multiplexing, code division multiplexing, and wavelength multiplexing, including their application in fiber to the home/fiber to the premises (FTTH/FTTP) networks for fast data transfer (asynchronous transfer mode (ATM) or Ethernet based) and for broadband service distribution (such as CATV). In the research laboratories, techniques aiming at next-generation optical access are being studied, such as wavelength routing for flexible capacity allocation and easily adaptable hosting of services and service providers, and radio-over-fiber techniques creating a powerful symbiosis of the fiber world and the wireless world by enabling centralized radio signal processing.     

Evaluation of 2-trees of a graph

A computer-oriented algorithm for the simultaneous enumeration of sets of 2-trees W1,1? and W2.2? is given. A test to identify elements of W1 2,1?,2? and W1 2?,1?2 from the above sets is also included.     

Computer-Aided Synthesis of Planar Circuits

This paper presents a fully computer-oriented iterative synthesis of an open-boundary planar circuit having an impedance matrix with prescribed poles and residues. A starting circuit pattern is given first, and it is represented by a finite number of parameters. Those parameters (and hence, the pattern) are then iteratively modified by using the Newton-Raphson method to realize the prescribed circuit characteristics. When the numbers of given poles and coupling ports are relatively small, the results are satisfactory both in the computing time and accuracy. Some numerical examples are given.     

A general formulation for iterative restoration methods

Information theory-based techniques for signal or image restoration and resolution enhancement are now considered a viable alternative to other popular techniques. In this correspondence, we present a general iterative mapping derived using an information theoretic criterion of optimality. A mathematical structure is defined followed by an analysis of the mapping, based on this structure. The convergence of the mapping is considered both in the general formulation and for a particular example. Some popular techniques are shown to be special cases of this general mapping     

Modeling of a distributed access protocol for an ATM satellitesystem: an algorithmic approach

An algorithmic model for the performance evaluation of the medium access control (MAC) protocol for a satellite system in an asynchronous transfer mode (ATM) environment is presented. This model allows analysis of general load configurations and yields the mean value of the performance parameters (e.g. queue lengths and access delays). The model is based on a computer-oriented approach, and the characterization of the key model variables is obtained by means of an iterative procedure. A comparison of the model analysis results to those obtained by a simulative approach shows a satisfactory matching     

Computer-Oriented Synthesis of Optimum Circuit Pattern of 3-dB Hybrid Ring by the Planar Circuit Approach

A fully computer-oriented synthesis of the optimum circuit pattern of a 3-dB hybrid ring based upon the planar circuit concept is described. In the synthesis process, the contour-integral method, and Powell's method are used for the circuit analysis, the optimization, respectively. The synthesized optimum patterns are given in normalized curves, parameters which can directly be used in practical circuit design. The validity of the theory is confirmed by experiment. It is shown both theoretically, experimentally that the planar circuit approach can, not only prevent the deterioration of the hybrid characteristics due to the widening of the circuit, but bring forth hybrid characteristics somewhat better than the distributed constant model. It is also shown that the obtained optimized characteristics can further be improved by addition of simple external circuits.     

Combinatorial Techniques for Fault Identification in Multiterminal Networks

A procedure is proposed for identification and diagnosis of faults in multiterminal devices. A combinatorial technique determines the number of x-terminal y-port nonredundant sub-networks which can be generated from a z-terminal parent network. This information is intended to identify and isolate internal faults of the system through an optimal set of external measurements. An elementary tutorial introduction to the terminology and procedures of combinatorial analysis aims to make this account self-contained and useful to the reliability engineer without a specialized mathematical background. Four-terminal and five-terminal devices are examined first. The results are then so formulated as to yield algorithms for computer-oriented procedures to identify the complete set of nonredundant configurations of a multiterminal network. The flowchart of operations suitable for a computer program is presented.     

Applications of micromechatronics in minimally invasive surgery

Many surgical procedures are now performed using the techniques of minimally invasive surgery (MIS), in which unnecessary trauma is limited by reducing the size of incisions to less than about 1 cm or by using catheters or endoscopes threaded through vessels, the gastrointestinal tract, or other tubular structures. Micromechatronic technologies have great potential to allow access to regions now inaccessible, or to enhance the surgeon's abilities in applications where current minimally invasive techniques do not permit the full range of human dexterity and perception. Key needs and applications in MIS are identified, and relevant technologies, methods, and systems issues in mechatronics are discussed. The authors' millirobotic system for MIS of the abdomen is used as an example     

Linearized transmitters: an enabling technology for softwaredefined radio

Power amplifier and transmitter linearization techniques are now a mature technology, with feedforward systems installed in many US base station sites for both TDMA and CDMA systems. Similarly, transmitter linearization techniques, such as Cartesian loop and predistortion, have been employed in mobile and portable equipment, and these have enabled a number of systems (e.g., iDEN in the United States and TETRA in Europe) to be realizable from a power consumption, cost, and size perspective. Such techniques are essential in the realization of an efficient and cost-effective software-defined radio system, whether deployed in a base station or a handset, and are thus a key enabling technology, without which SDR will not succeed. This article examines the current status of power amplifier and transmitter linearization technologies for mobile and base station equipment, and highlights some of the novel base station and network topologies now emerging based on these techniques. In many cases, these new topologies will revolutionize the way a cellular network is constructed and lead to very substantial cost reductions for a network operator     

Dynamic Magnetic Properties of Ferroic Films,Multilayers, and Patterned Elements

Modification and control of material properties through careful manipulation of geometry on nano‐ and sub‐nanometer length scales is a cornerstone of modern materials science and technology. An exciting area in which these concepts have provided exceptional advances has been magnetoelectronics and nanomagnetism. Important scales in magnetic metals are conduction spin diffusion lengths and distances over which local moments correlate. Advanced techniques now allow for the creation of structures patterned on these length scales in three dimensions. The focus of this article is on magnetic structures whose dynamic properties can be strongly modified by ion bombardment and lithographic patterning. Examples are given of how microwave frequency properties can be tuned with external fields, how factors controlling magnetic switching can be controlled, and how manipulation of magnetic domain walls can be used to reveal new and surprising phenomena.     

MSTP应用于大容量的xDSL用户线汇聚传输

本文主要结合了当前电信运营商在开展xDSL中面对的实际问题,结合MSTP的特点,提出了全新的详细的解决方案.通过本文的详细讨论,我们可以看出利用MSTP实现xDSL用户线的汇聚将比传统的ATM交换网具有更大的优势.     

Efficient multibeam synthesis with interference ing for large arrays

This paper describes a class of multibeam synthesis algorithms that are useful for large arrays when simultaneous ing of interference is required. In these algorithms, the computational cost is kept small by using fast Fourier transform (FFT) beamforming, while at the same time interference is ed using spatial projections. Once the interference steering vectors are determined, these algorithms have a computational cost per output which is only slightly greater than that of the FFT with no interference ing. In addition, techniques are derived that allow the Fourier beams to be protected against distortion by constraining the patterns, reducing the pattern variation, or both. These techniques may be particularly well suited for some new radiotelescopes now in the planning stages.