A decision support system for interactive decision making-Part I: model formulation

A comprehensive decision support system, GMCR II, is developed for the systematic study of real-world interactive decision problems. Model formulation is presented in Part I, and analysis and output interpretation in Part II. GMCR II is based upon existing and new research developments of the graph model for conflict resolution. In Part I, specially designed data structures and corresponding algorithms are implemented for generating and representing possible states, removing infeasible states, coalescing indistinguishable states, and specifying and storing allowable state transitions. Algorithms implementing different approaches to the elicitation of preferences over states enable GMCR II to construct and manage an efficient, flexible, and complete graph model of a strategic conflict.     

Strategic decision support for the services industry

The graph model for conflict resolution and the associated decision support system GMCR II are presented as a comprehensive service tool that can provide strategic advice to leaders and managers, in industry, government and other organizations, who must ensure the success of their enterprises within an increasingly competitive environment on a local, national, or international level. In addition to furnishing an overview of the graph model and the design of GMCR II, this paper describes general situations in which advisors providing a decision support service may use this unique computerized technology. An international trade dispute is utilized to illustrate how GMCR II can be applied to study real-world interactive decision making systematically and effectively     

An Overview of Analog Feedback Part I: Basic Theory

This two part paper addresses the genuinely difficult problem of efficiently analyzing and designing high performance analog feedback networks. Part I focuses on theoretical considerations and is therefore independent of device technology. Part II exploits the results formulated in Part I to develop models, computationally efficient analytical methods, and design criteria for six types of commonly used feedback architectures. The utility of these models, methods, and criteria is applicable to monolithic bipolar junction transistor, MOS, CMOS, and other device technologies. Part I specifically overviews the traditional mathematics that underlie the study of the circuit transfer, driving point impedance, and frequency response characteristics of analog feedback networks. This review establishes a foundation for developing a computationally efficient form of signal flow theory that embellishes these analytical methods and illuminates design-oriented insights that are otherwise obscured by the tedium pervasive to traditional analyses. The new form of classical signal flow theory, which is a hybrid of signal flow and two-port network theories, is introduced in Part I and developed fully in Part II. This hybrid method of feedback circuit analysis allows for an efficient assessment of the gain, bandwidth, sensitivity, stability, and input/output impedance characteristics of a broad variety of global feedback loops. Additionally, the method complements the task of formulating engineering design guidelines for feedback network design by highlighting the attributes and limitations implicit to specific types of feedback configurations.     

Gain scheduler middleware: a methodology to enable existing controllers for networked control and teleoperation-part II: teleoperation

This paper is the second of two companion papers. The foundation for the external gain scheduling approach to enable an existing controller via middleware for networked control with a case study on a proportional-integral (PI) controller for dc motor speed control over IP networks was given in Part I. Part II extends the concepts and methods of the middleware called gain scheduler middleware (GSM) in Part I to enable an existing controller for mobile robot path-tracking teleoperation. By identifying network traffic conditions in real-time, the GSM will predict the future tracking performance. If the predicted tracking performance tends to be degraded over a certain tolerance due to network delays, the GSM will modify the path-tracking controller output with respect to the current traffic conditions. The path-tracking controller output is modified so that the robot will move with the fastest possible speed, while the tracking performance is maintained in a certain tolerance. Simulation and experimental results on a mobile robot path-tracking platform show that the GSM approach can significantly maintain the robot path-tracking performance with the existence of IP network delays.     

Reliability Optimization of a Series-Parallel System

A mathematical model is formulated for optimizing the reliability of a system subject to given linear constraints; the system has several stages in series; each stage has parallel redundancy to improve the reliability. Part I shows a new way to transform the model of constrained optimization to a saddle point problem by using Lagrange multipliers. Conditions are derived for maximizing the reliability function; Newton's method is used to solve the resulting multidimensional nonlinear algebraic equations. Further modifications are provided to avoid inverting the large Jacobian matrices; therefore this method is practical for large systems. Part II shows how to transform the model of constrained optimization to a multistage decision process and uses the Maximum principle to arrive at the optimal decision. This approach is easy to apply, formulate, and program. The solution can be obtained without fear of nonconvergence (very often experienced with earlier methods) besides providing considerable saving in computer time. Design alternatives can be easily considered.     

用数据仓库来实现决策支持

阐明了决策相关的一些问题，说明了决策支持系统的演变历程、系统构成等内容，明确了决策支持系统的整体结构。对数据仓库以及相关的数据准备，联机分析处理和数据挖掘等技术进行了研究，说明了数据仓库辅助决策的方式。对如何搭建一个基于数据仓库的决策支持系统进行了比较深入的论述。     

The traveling-wave phototube part II: Experimental analysis

This paper reports a detailed experimental investigation of the traveling-wave phototube (TWP) as a broad-band demodulator of microwave-modulated light. As Part II of a theoretical and experimental analysis of the interaction between a density-modulated photoelectron beam and a slow-wave circuit, it examines the output power, bandwidth and voltage modewidth of the traveling-wave phototube as a function of photocurrent, beam voltage and interaction length. Three types of experiments are described: 1) direct demodulation of light, amplitude-modulated at 3 Gc by a cavity-type modulator, 2) measurement of the microwave shot noise from photoelectron beams initiated by light from both coherent and incoherent sources and 3) comparison of the previous two measurements with the microwave shot noise of a thermionic electron beam. Comparisons of the results of these experiments with the predictions of the theory of Part I are drawn, showing good agreement. In particular, a number of new effects which are predicted by the detailed analysis of Part I, and which had not been previously observed or predicted are reported.     

A Unified Approach to Serial Search Spread-Spectrum Code Acquisition--Part II: A Matched-Filter Receiver

The unified theory developed in Part I [1] is employed here in the analysis of a noncoherent, matched-filter (fast-decision-rate) code acquisition receiver in a direct-sequence spread-spectrum system. The results illustrate the dynamic dependence of the mean acquisition time on system parameters, such as the predetection signal-to-noise ratio (SNR), the decision threshold settings, and the ratio of the decision rate to the code rate.     

Computationally efficient methods for blind decision feedback equalization of QAM signals

This paper investigates computationally efficient methods for blind decision feedback equalization (DFE) that reduce the complexity and power requirements of blind equalization algorithms while maintaining their steady-state characteristics for quadrature amplitude modulation (QAM) signals. These include the power-of-two error (POT), selective coefficient update (SCU), and frequency-domain block (FDB) methods. A novel radius-directed stop-and-go (RSG) method is introduced, which selectively adjusts the equalizer tap coefficients based on the equalizer output radius. In addition, a new activation/de-activation method based on the equalizer output radius is utilized to control the feedback equalizer (FBE) of the DFEs. Simulation studies and analysis are provided for empirically derived cable and microwave channels and Ricean fading channels.     

Toward a decision informatics paradigm: a real-time, information-based approach to decision making

The focus of this paper is on decision making; more specifically, on what decision making requirements are needed in the future. We augur for a decision informatics paradigm; it is a real-time, information-based approach to decision making. The paradigm is supported by two sets of technologies (i.e., information and decision technologies) and underpinned by three disciplines (i.e., data fusion/analysis, decision modeling, and systems engineering). We begin by considering the context - and needs - for decision making as the economies of the world change and evolve, especially in regard to emerging services; then our proposed decision informatics paradigm is detailed and illustrated, together with an in-depth review of a critical, underpinning research area (dealing with real-time fusion and analysis of multiple nonhomogeneous data sources), followed by several concluding remarks.     

Optimum Reception in an Impulsive Interference Environment--Part II: Incoherent Reception

In Part I, the relevant statistical properties of the recently developed statistical-physical model of generalized impulsive interference have been briefly reviewed (for sub Class A noise) and then applied specifically to optimum coherent detection. It is shown that by using optimum and (locally optimum) detection algorithms (canonically and explicitly derived), substantial savings in signal power and/or spectrum space can be achieved for operation in these highly nonGaussian interference environments. This paper (Part II) extends the preceding analysis to cover various important cases of incoherent reception. The same general model for narrow-band (Class A) impulsive interference and interference examples used in Part I are again employed here. In addition to providing both canonical LOBD structures and expressions for performance, this permits explicit quantitative comparisons between coherent and incoherent reception for common classes of specific digital signal waveforms.     

Proportional Fairness in Multi-Channel Multi-Rate Wireless Networks-Part I: The Case of Deterministic Channels with Application to AP Association Problem in Large-Scale WLAN

This is Part I of a two-part paper series that studies the use of the proportional fairness (PF) utility function as the basis for resource allocation and scheduling in multichannel multi-rate wireless networks. The contributions of Part I are threefold. (i) We present the fundamental properties and physical/economic interpretation of PF optimality. We show that PF leads to equal airtime allocation to users for the singlechannel case; and equal equivalent airtime allocation to users for the multi-channel case. In addition, we also establish the Pareto efficiency of joint-channel PF optimal solution (the formulation of interest to us in this paper), and its superiority over the individual-channel PF optimal solution in that the individual user throughputs of the former are all equal to or greater than the corresponding user throughputs of the latter. (ii) Second, we derive characteristics of joint-channel PF optimal solutions useful for the construction of PF-optimization algorithms. In particular, we show that a PF solution typically consists of many zero airtime assignments when the difference between the number of users U and the number of channels S, |U ? S|, is large. We present several PF-optimization algorithms, including a fast algorithm that is amenable to parallel implementation. (iii) Third, we study the use of PF utility for resource allocation in large-scale WiFi networks consisting of many adjacent wireless LANs. We find that the PF solution simultaneously achieves higher system throughput, better fairness, and lower outage probability with respect to the default solution given by today?s 802.11 commercial products. Part II of this paper series extends our investigation to the time-varying-channel case in which the data rates enjoyed by users over the channels vary dynamically over time.     

C-fuzzy decision trees

This paper introduces a concept and design of decision trees based on information granules - multivariable entities characterized by high homogeneity (low variability). As such granules are developed via fuzzy clustering and play a pivotal role in the growth of the decision trees, they will be referred to as C-fuzzy decision trees. In contrast with "standard" decision trees in which one variable (feature) is considered at a time, this form of decision trees involves all variables that are considered at each node of the tree. Obviously, this gives rise to a completely new geometry of the partition of the feature space that is quite different from the guillotine cuts implemented by standard decision trees. The growth of the C-decision tree is realized by expanding a node of tree characterized by the highest variability of the information granule residing there. This paper shows how the tree is grown depending on some additional node expansion criteria such as cardinality (number of data) at a given node and a level of structural dependencies (structurability) of data existing there. A series of experiments is reported using both synthetic and machine learning data sets. The results are compared with those produced by the "standard" version of the decision tree (namely, C4.5).     

Linear time-variant transformations of generalized almost-cyclostationary signals.II. Development and applications

For pt. I see ibid., vol.50, no.12, p.2947-61 (2000). In Part I, the problem of the linear time-variant (LTV) filtering is addressed in the fraction-of-time (FOT) probability framework. The adopted approach, which is an alternative to the classical stochastic one, provides a statistical characterization of the systems in terms of functions that can be estimated by a single time-series. The analysis is carried out with reference to the wide class of the generalized almost-cyclostationary (GACS) signals, which includes, as a special case, the class of the almost-cyclostationary (ACS) signals. Examples of applications and developments of the theory introduced in Part I are presented here in Part II. Specifically, the countability of the set of the output cycle frequencies is studied with reference to linear time-variant systems for both ACS and GACS not containing any ACS component input signals. Thus, the linear almost-periodically time-variant filtering and the product modulation are considered in detail. Moreover, several Doppler channel models are analyzed. In all these examples, it is shown that the FOT probability approach allows one to characterize the system and its output in terms of statistical functions that can be measured by a single time-series. Furthermore, the usefulness of considering the linear filtering problem within the class of the GACS signals is clarified, and several pitfalls arising from continuing to adopt for the observed time-series the ACS model when an increase in the data-record length makes the GACS model more appropriate are pointed out.     

The effect of decision delay in finite-length decision feedbackequalization

In this correspondence we derive the finite-length, minimum mean-squared error decision feedback equalizer (MMSE-DFE). We include decision delay as an explicit parameter. Our derivation yields an algebraic interpretation of the effect of decision delay on DFE performance (measured by mean-squared error). It also allows the fast computation of the MMSE-DFE for several different values of both decision delay and the number of feedback taps. Our approach is especially useful for short filter lengths, when the decision delay can significantly affect DFE performance     

Channel Capacity Between Antenna Arrays— Part II: Amplifier Noise Dominates

In this paper (Part II of two), we continue examining the use of space-time coding techniques to achieve very-high spectral efficiencies in highly scattering environments, using multiple transmit and receive antennas. The goal is to increase as much as possible the number of antenna elements, which is particularly difficult at the remote station, which usually has a more limited space allotted to the antenna array than at the base station. Under the assumption that sky noise was the dominant noise source, Part I addressed the channel-capacity effects of mutual impedance between antenna elements in the remote array, and the correlation between the signal and noise fields received by these elements. In Part II, we consider the same effects under the assumption that amplifier noise is the dominant noise source. The question of how closely the receiving array elements can be spaced depends on how precisely the channel can be estimated. This is related to the high-precision requirement experienced with supergain antenna arrays. The supergain connection is made explicit by showing that the optimum channel capacity for the case of a single transmitting element is achieved by using the supergain weights for the receiving array. To indicate the effect of noisy channel estimation, the loss in receiver antenna gain due to noise in weight estimates is computed with a simple simulation model of scattered propagation for the single-transmitting-antenna element case     

Decision analysis: Perspectives on inference, decision, and experimentation

This paper illustrates by using a simple coin-tossing example how the new discipline of decision analysis sheds light on the perennial problems of inference, decision, and experimentation. The inference problem is first discussed from the classical viewpoints of maximum likelihood estimation and hypothesis testing, and then from the viewpoint of subjective probability and Bayesian updating. The problem is next placed in a decision setting to demonstrate how an estimate is related to the nature of the loss structure. Experimental possibilities are evaluated for the case where the size of the experiment must be determined a priori and for the case where experimentation can cease at any point. The decision-analysis philosophy allows consideration of all these problems within one philosophical and methodological framework.     

An analysis of the performance of a handset diversity antennainfluenced by head, hand, and shoulder effects at 900 MHz .II.Correlation characteristics

For pt.I see ibid., vol.50, no.3, p.830-44 (2001). In Part I of this two-part paper, we described the effective gain characteristics of the handset diversity antenna comprising a retractable whip antenna and a built-in planar inverted F antenna (PIFA). In order to achieve a high diversity effect, the correlation between the diversity branches must be small while at the same time maintaining a high effective gain, and this is contained in this paper. Further analysis includes an evaluation of the diversity gain with which the diversity effect shown by the analyses of the effective gain in Part I and the correlation in Part II is described. In addition, the mechanism for obtaining a small correlation coefficient is clarified by investigating the amplitude and phase radiation patterns when the whip length and the body inclination angle are changed. From these we obtain various numerical results that provide sufficient insight for design purposes. The validity of the analytical results is verified by an experiment in an indoor radio wave propagation environment     

Probability of Error Analyses of a BFSK Frequency-Hopping System with Diversity Under Partial-Band Jamming Interference--Part III: Performance of a Square-Law Self-Normalizing Soft Decision Receiver

Linear and nonlinear diversity combining receivers for multihops-per-bit FH/BFSK waveforms in the partial-band noise jamming environment were studied in Parts I and II. It was shown that nonlinear combining receivers (Part II) can achieve a diversity gain for error rate improvement, while the linear combining receiver (Part I) cannot. The two types of nonlinear combining receivers treated in Part II required knowledge of system operational parameters for their optimum performance, such as measured noise power and the signal energy level at the receiver. In this paper, a self-normalizlng nonlinear combining receiver is shown to achieve a diversity gain without knowledge of signal or jamming levels, unlike the nonlinear schemes studied previously. The worst-case error probability performance of the self-normalizing receiver is obtained with and without system thermal noise. The numerical results are compared to those for the receivers studied earlier.