An exploratory study into whether to or not to include users in the development of industrial hypermedia applications

While there is agreement among both information system (IS) practitioners and IS researchers as to the value of user participation in IS development, the correlation between user participation and actual use or user satisfaction (surrogate measures of IS success) has been equivocal. A possible reason for the contradictory findings could be that user participation is being utilised, regardless of the levels of complexity of either the system or the task. This paper describes two exploratory case studies to test this hypothesis. Industrial hypermedia applications (IHA) were developed and qualitative data collected, through usability trials, to see the effect of user participation on user perception (extrinsic motivations of use) of the system, rather than IS success. The findings show that users should participate in the development when both the IS and the task are complex. On the other hand, when both the system and the task are not complex, user participation can be kept to a minimum. Furthermore, it is recommended that user participation should not be evaluated against IS success, but against system features.

The verified software repository: a step towards the verifying compiler

The verified software repository is dedicated to a long-term vision of a future in which all computer systems justify the trust that society increasingly places in them. This would be accompanied by a substantial reduction in the current high costs of programming error, incurred during the design, development, testing, installation, maintenance, evolution, and retirement of computer software. An important technical contribution to this vision will be a verifying compiler: a tool-set that automatically proves that a program will always meet its specification, insofar as this has been formalised, without even needing to run it. This has been a challenge for computing research for over 30 years, but the current state of the art now gives grounds for hope that it may be implemented in the foreseeable future. Achievement of the overall vision will depend also on continued progress of research into dependability and software evolution, as envisaged by the UKCRC Grand Challenge project in dependable systems evolution. The verified software repository is a first step towards the realisation of this long-term vision. It will maintain and develop an evolving collection of state-of-the-art tools, together with a representative portfolio of real programs and specifications on which to test, evaluate, and develop the tools. It will contribute initially to the inter-working of tools, and eventually to their integration. It will promote transfer of the relevant technology to industrial tools and into software engineering practice. It will build on the recognised achievements of practical formal development of safety-critical computer applications, and contribute to an international initiative in verified software, covering theory, tools, and experimental validation. Received April 2005 Revised November 2005 Accepted November 2005 by C. B. Jones     

Bessel function of the first kind with complex argument

A new method of computing integral order Bessel functions of the first kind J_n(z) when either the absolute value of the real part or the imaginary part of the argument z = x + iy is small, is described. This method is based on computing the Bessel functions from asymptotic expressions when x∼ 0 (or y ∼ 0). These expansions are derived from the integral definition of Bessel functions. This method is necessary because some existing algorithms and methods fail to give correct results for small x small y. In addition, our overall method of computing Bessel functions of any order and argument is discussed and the logarithmic derivative is used in computing these functions. The starting point of the backward recurrence relations needed to evaluate the Bessel function and their logarithmic derivatives are investigated in order to obtain accurate numerical results. Our numerical method, together with established techniques of computing the Bessel functions, is easy to implement, efficient, and produces reliable results for all z.     

Worst-case design in the time domain: The maximum principle and the standardH ∞ problem

This paper presents a time-domain, optimal-control approach to worst-case design, an alternative to frequency-domainH _∞ techniques. The generic linear-quadratic set-up of the “standardH _∞ problem” is discussed. The resultsinclude a characterization of suboptimal values, as well as a parametrization of all suboptimal compensators, interms of two coupled indefinite Riccati equations. Both the usual infinite-horizon, time-invariant case and the finite-horizon, time-varying case, are treated. The latter is beyond the scope of frequency-domain analysis. An earlier version of this work was prepared at the Center for Control Sciences, Brown University, and was supported in part by the Air Force Office of Scientific Research under Contract F49620-86-C-011.     

An H-minimax approach to the design of robust control systems, part II: All solutions, all-pass form solutions and the ‘best’ solution

We characterize all solutions to a robustness optimization problem as the solutions of a two-parameter interpolation problem. From this characterization it is easy to show that an all-pass form solution always exists as long as a solution exists. We also study the possibility of using non-all-pass form solutions and by introducing other optimization objectives (motivated by improvements in disturbance rejection and robust stability) we search for the 'best' solution.     

基于SVM的流行音乐中人声的识别

针对流行音乐中人声的发现问题,使用SVM分类器针对MFCC特征进行训练和分类。依据音频特征的连续性,后期对分类结果进行低通滤波。实验结果表明,该方法在帧层面上的识别率可以达到85.76%。实验中也发现不同语种的演唱者在发音上,特别是在MFCC特征上存在很大的统计差异性。实验中对歌曲分类的结果可以作为近一步实现音乐相似性度量的依据之一。     

Chemical Genetic Programming – evolutionary optimization of the genotype-to-phenotype translation set

A new method of genetic programming, named chemical genetic programming (CGP), which enables evolutionary optimization of the mapping from genotypic strings to phenotypic trees is proposed. A cell is evolved which includes a DNA string that codes the fundamental mapping from the DNA code to computational functionality. Genetic modification of a cell's DNA allows the DNA code and the genotype-to-phenotype translation to coevolve. Building an optimal translation table enhances evolution within a population while maintaining the necessary diversity to explore the entire search space. This work was presented in part at the 9th International Symposium on Artificial Life and Robotics, Oita, Japan, January 28–30, 2004     

Building intelligent collaborative interface agents with the ICAGENT development framework

This paper describes the implementation of intelligent collaborative interface agents using the intelligent collaborative agent (ICagent) development framework. In particular, the paper presents the implementation of a collaborative interface agent that acts as a tutor in the context of an educational software application. The agent deliberates socially with users following the SharedPlans model of collaborative activity. Social deliberation requires interface agents to make their desires and intentions clear to the application users, being in constant communication with them, to understand the context of their activity and to reconcile their own and users’ desires in the overall context of action. Reconciliation of users’ desires allows agents to recognize the situations where users need help. The paper briefly presents the ICagent development framework, describes the implementation of the interface agent, and discusses an example of the behavior of the agent during a collaboration session.     

噪声环境下基于单高斯模型的声道归一化研究

声道归一化是语音识别中说话人自适应的方法之一,在噪声环境下对其进行了研究并做了一系列的实验.在实现过程中,首次在噪声环境下采用了基于单高斯混合模型选择弯折因子的方法,并取得了良好的结果.实验基于AURORA语音数据库,并用其所带的汽车噪声环境下的测试集对模型进行了识别验证.实验结果表明,采用声道归一化后的识别结果在各个噪声下均比原来有不同程度的改善,迭代训练能改进单轮声道归一化的结果,最佳结果出现在迭代训练的第三轮.噪声环境下基于一个高斯混合模型选择的弯折因子相比其他高斯混合模型选择的弯折因子,句子平均识别率提高了近1.68%.经过声道归一化后的性别独立模型的识别结果能接近于未经声道归一化后的性别依赖模型的识别结果,如果训练数据充分,声道归一化后的性别独立模型的识别结果能更好.     

Mixed controllers for SISO discrete time systems

In this paper we present a methodology for designing mixed controllers. These controllers allow for minimizing the worst-case peak output due to a persistent disturbance, while, at the same time, satisfying an norm constraint upon some closed-loop transfer function of interest. Thus, they are of interest for applications dealing with mixed time/frequency domain performance specifications. The main result of the paper shows that suboptimal mixed controllers can be obtained by solving a sequence of problems, each one consisting of a finite-dimensional convex optimization and a standard, unconstrained problem.     

On the status and prospects of systems analysis methods in ukraine

The paper deals with the role and place of systems analysis methods in the solution of complex problems in various spheres of human activity in Ukraine. The social and socio-economic prerequisites for development of theory and applied methods are being considered. The main characteristics of the problems to which these methods are applied are formulated. The hierarchy of problems and methods used for solution of complex problems based on systems analysis methods is presented, and the main spheres of their application in Ukraine are presented. Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 101–109, January–February, 2000.     

On pure H reduced-order dynamic controllers: an erratum

There are at least two approaches advocated to obtain a pure H^∞ reduced-order dynamic controller for a given augmented plant. One approach is to eliminate completely the H² aspect from a standard H²/H^∞ setting. A second approach is to equate the H² aspect with the H^∞ aspect in that same setting. This paper invalidates the first approach but affirms the second approach and produces the correct equations resulting therefrom.     

Stabilization and H control of symmetric systems: an explicit solution

In this paper we address the H^∞ control analysis, the output feedback stabilization, and the output feedback H^∞ control synthesis problems for state-space symmetric systems. Using a particular solution of the Bounded Real Lemma for an open-loop symmetric system we obtain an explicit expression to compute the H^∞ norm of the system. For the output feedback stabilization problem we obtain an explicit parametrization of all asymptotically stabilizing control gains of state-space symmetric systems. For the H^∞ control synthesis problem we derive an explicit expression for the optimally achievable closed-loop H^∞ norm and the optimal control gains. Extension to robust and positive real control of such systems are also examined. These results are obtained from the linear matrix inequality formulations of the stabilization and the H^∞ control synthesis problems using simple matrix algebraic tools.     

Existence of discrete-time LQG-controllers

Existence results for the LQG-controller are investigated. An infimal Riccati equation based controller may potentially give closed loop eigenvalues on the unit circle. Assuming left and right invertibility it is shown that there exists an optimal controller if and only if the Riccati equation based controller stabilizes the closed loop system after removal of all its unobservable and uncontrollable modes. Furthermore this reduced controller is the optimal controller, and its transfer function is unique. This existence condition is a considerable simplification of the more general geometric condition recently derived by Trentelman and Stoorvogel.     

Linking the growth of filamentous algae to the 3D-ecohydrodynamic model of the Gulf of Finland

One of the most visible symptoms of eutrophication in the Gulf of Finland is blooms of unattached filamentous algae. This decomposing algal biomass causes serious nuisance problems for recreational uses of the coastal zone, particularly when cast ashore. The nutrient availability for these macroscopic filamentous algae is regulated by a superior competitor, the phytoplankton. Nutrients are left for the weaker competitor only when the conditions are not suitable for the growth of phytoplankton. This happens during vertical mixing of the water column. The lack of stratification prevents the formation of phytoplankton blooms, but does not limit the growth of filamentous algae when still growing attached to the bottom. A simple growth model was developed to describe the growth and biomass of filamentous algae. In the absence of suitable nutrient measurements, the model was linked to a 3D-ecohydrodynamic model which generated the nutrient input data. The model was calibrated with three-year monitoring data of filamentous algal biomass at one location. Validation was carried out with one-year monitoring data from an adjacent location. The model was able to describe the number of biomass peaks and their timing with good accuracy. After further development, the filamentous algal model will be used as one of the management tools for the evaluation of the sustainable nutrient load to the Gulf of Finland.     

A note on the structure of two subsets of the parameter space in adaptive control problems

We study the geometric structure of two subsets of the parameter space that are of interest in the context of adaptive LQ-control. The first set can be considered as the set of possible limit points of an adaptive control algorithm, whereas the second can be seen as the set of desirable limit points. Our main result is that these sets are C^ω-manifolds.     

On the solution of coupled Riccati equations used in mixed H2 and H∞ optimal control

This paper considers a set of three coupled Riccati equations. The solution of these equations constitutes necessary conditions for mixed H₂ and H_∞ control problems. The main contributions of the paper are related to the conditions under which the solution of these equations is unique as well as to characterize necessary and sufficient conditions for the existence of solutions.     

On the strict logic foundation of fuzzy reasoning

This paper focuses on the logic foundation of fuzzy reasoning. At first, a new complete first-order fuzzy predicate calculus system K^* corresponding to the formal system L^* is built. Based on the many-sort system K_ms^* corresponding to K^*, the triple I methods of FMP and FMT for fuzzy reasoning and their consistency are formalized, thus fuzzy reasoning is put completely and rigorously into the logic framework of fuzzy logic.The author is indebted to anonymous referee for his useful comments which have helped to improve the paper.     

Achieving nonvanishing stability regions with high-gain cheap control using H techniques: the second-order case

This paper demonstrates how to use an asymptotically H^∞-optimal controller to stabilize a second-order system subject to unknown disturbances such that the stability region does not vanish as the feedback gains increase. The high-gain feedback arises when one attempts to achieve the lowest achievable limit of the disturbance attenuation under the H^∞ design. This type of gain increase can cause the stability region to vanish if the disturbance contains nonlinear terms. The analysis using Lyapunov techniques derives a sufficient condition on the design parameters to prevent the stability region from vanishing. In addition to describing exact solutions for six different cases, the paper provides simulations to illustrate the results.