Processes of transforming structures

Transformations of relational structures by applying productions have been studied. Processes of transforming structures are considered and a method of composing such processes is developed. The processes generalize derivation trees of context-free grammars. The method of composing processes generalizes the operations on derivation trees. Church-Rosser properties of processes are stated.     

A class of scheduling policies for mixed data with renewal arrivalprocesses

Two mutually independent traffic streams whose arrivals are modeled as renewal processes are considered. The arrivals are stored in an infinite capacity buffer. One of the processes requires a strict upper bound on the total delay per arrival, and it is assumed that the processing time per arrival for both processes is a constant. Given the above model, the class of nonpreemptive scheduling policies which satisfy the delay constraint while maintaining the system stability is found. The delays induced by the latter policy are analyzed via a methodology based on the regenerative theorem. A numerical example is given in which the policy that minimizes the expected delays for both traffic streams is also considered     

Living cell as a universal computer

A number of similarities between living cells and universal computers are considered. Intracellular life processes are compared to computation processes inside a computer. Proteins coordinating intracellular processes are associated with computer programs during runtime. The possibility of the existence of a genetic programming language that allows effectively building new genes from the existing ones is considered.     

Complexity of verification of nondeterministic probabilistic multiagent systems

Probabilistic systems of interacting nondeterministic intelligent agents are considered. The states of agents in such systems are probabilistic databases (of facts), and their actions are controlled by probabilistic logical programs. Besides, communication channels between agents are also probabilistic. It is shown how such systems can be transformed in poynomial time to equivalent finite Markov decision processes. This makes it possible to translate the known results on the verification of the dynamic properties of the finite Markov processes to the probabilistic multiagent systems of the considered type.     

Stochastic convexity for multidimensional processes and itsapplications

A multidimensional stochastic process is considered which is a function of a parametric process. The parametric process may be multidimensional as well. Two such processes are compared that differ only in their parametric processes. Known stochastic convexity results for one-dimensional stochastic processes are extended to multidimensional processes. These results are used to obtain comparison results for various queuing systems that are subject to different parametric processes, which may be the arrival processes, service processes, etc. Based on these comparison results it is shown how the performances of queueing systems can be affected by the variability of parametric processes     

The Behavior of the Generator Normalization Factor in Approximation of Random Processes

Markov random evolutions and their approximations are analyzed. The main object of study is generators of random processes with independent increments. These processes are considered in Poisson approximation and Levy approximation schemes. Generators of random processes are normalized by parameters that are nonlinear functions. The explicit form of such normalization parameters is shown. The asymptotic representation of generators in both approximation schemes is shown. Normalizing factors of random evolution are presented.     

Two approximation methods to synthesize the power spectrum of fractional Gaussian noise

The simplest models with long-range dependence (LRD) are self-similar processes. Self-similar processes have been formally considered for modeling packet traffic in communication networks. The fractional Gaussian noise (FGN) is a proper example of exactly self-similar processes. Several numeric approximation methods are considered and reviewed, two methods are found that are able to provide a better accuracy and less running time than previous approximation methods for synthesizing the power spectrum of FGN. The first method is based on a second-order approximation. It is demonstrated that a parabolic curve can be indirectly used to approximate the power spectrum of FGN. The second method is based on cubic splines. Despite the fact that splines cannot be used directly to approximate the power spectrum of FGN, they can, however, considerably simplify the calculations while maintaining high accuracy. Both of the methods proposed can be used to estimate the Hurst parameter using Whittle's estimator. Additionally, they can be used on synthesis of LRD sequences.     

Improved quality of continuous flow manufacturing through the combination of statistical process control and conventional computer process control

This paper represents a portion of the evaluation of the use of Statistical Process Control within the realm of Conventional Computer Process Control. Various control charts commonly utilized in continuous processes are evaluated when subjected to process disturbances typical of continuous processes. The control charts considered are the Moving Average and Moving Range Chart combination, the Individual and Moving Range Chart combination, and the Exponentially Weighted moving Average Chart. The types of process disturbances considered are unit step and linear trend disturbances to the process average. The evaluation is based on the determination of the Average Run Lengths (ARLs) resulting from computer simulations.     

Behaviours of concurrent systems

Concurrent systems and their behaviours are investigated. The behaviour of a system is understood as the set of processes which the system is capable to realize. The processes may be elementary (indivisible) or may consist of some components. Two ways of composing processes are considered: sequentially (one component is a continuation of another) and in parallel (the components are concurrent, i.e. independent).The behaviour of a system is defined as a set of processes which can be obtained by composing certain elementary processes. All information on the existing independence is reflected so that the system is completely determined by its behaviour.It is explained which sets of processes are the behaviours of concurrent systems.     

间歇化工过程的能量综合优化策略

综述了三类间歇过程能量综合优化方法,分析了间歇过程的生产和用能特点.从间歇过程能量利用环节和能量回收环节相互制约的关系出发,提出了适用于间歇过程能量综合优化改进的一般方法,为精细化工过程的节能降耗提供理论指导.方法用于指导某聚酯生产过程的能量综合优化,取得了节能10%以上的效果,表明所提出的能量综合优化方法能有效指导间歇过程的全局用能优化改进.     

Multi-objective genetic programming approach for robust modeling of complex manufacturing processes having probabilistic uncertainty in experimental data

In this paper, a multi-objective uniform-diversity genetic programming (MUGP) algorithm deployed for robust Pareto modeling and prediction of complex nonlinear processes using some input-output data table. The uncertainties included in measured data are considered to obtain more robust models. The considered benchmarks are an explosive cutting and forming processes, in which the nonlinear behavior between the input and output of processes are detected using MUGP. For both case studies, a multi-objective modeling and prediction procedure firstly performed using deterministic data. Secondly, the same identification procedure carried out using probabilistic uncertainty in the experimental input-output data. The objective functions considered are namely, training error, prediction error and number of tree nodes (complexity of models) in the deterministic approach. Accordingly, the mean and standard deviation of training error and prediction error are considered in robust Pareto modeling and prediction of such processes. In this way, Pareto front of such modeling and prediction is first obtained for both explosive cutting and forming processes with deterministic data. Such Pareto front is then obtained using experimental input-output-data having probabilistic uncertainty in input parameters through a Monte Carlo simulation (MCS) approach. In addition, it has been shown that for both cases, the trade-off models obtained from deterministic data have significant biases when tested on data with probabilistic uncertainty. Finally, the obtained results of such multi-objective robust model identification show promising results in terms of compensating uncertainty in the experimental input-output-data.     

Exact solutions to two-dimensional homing problems

Two-dimensional controlled Wiener and Bessel diffusion processes are considered in circles. Both the infinitesimal means and variances of the controlled processes depend on the control variables. The processes are controlled until they hit the circles for the first time. The objective is to minimize the expected value of the time spent by the controlled processes inside the circles, while taking the control costs into account. Explicit and exact expressions are obtained for the optimal values of the control variables as well as for the value functions. The method of similarity solutions is used to solve the appropriate dynamic programming equation.     

Models of Two-Sided Monopolistic Competition on the Labor Market

Dynamic macromodels of an economic system with two-sided monopoly competition on the labor market are considered. Conditions for post-classical economic cycles to appear in such models and for the convergence of wage formation processes to Nash equilibrium are analyzed. The influence of technological innovations on the processes under study is analyzed.__________Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 25–34, March–April 2005.     

Parametric optimization of some non-traditional machining processes using artificial bee colony algorithm

Selection of the optimal values of different operating parameters is of utmost importance for enhancing the performance of various non-traditional machining (NTM) processes. The performance measures (responses) of different NTM processes usually include metal removal rate, surface roughness, radial overcut, tool wear rate, heat affected zone, etc. In this paper, artificial bee colony (ABC) algorithm is employed to search out the optimal combinations of different operating parameters for three widely used NTM processes, i.e. electrochemical machining, electrochemical discharge machining and electrochemical micromachining processes. Both the single and multi-objective optimization problems for the considered NTM processes are solved using this algorithm. The results obtained while applying the ABC algorithm for parametric optimization of these three NTM processes are compared with those derived by the past researchers, which prove the applicability and suitability of the ABC algorithm in enhancing the performance measures of the considered NTM processes.     

Protocol conversion

The problem of achieving communication between two processes across a network or an internetwork is considered. The notion of logical connectivity between processes in a protocol is formalized. The problem of constructing a protocol converter to achieve interoperability between processes that implement different protocols is addressed. A formal model is presented, based on the theory of protocol projection, for reasoning about the semantics of different protocols and conversions between them. Two kinds of converters are presented: memoryless converters and finite-state converters. The construction of some finite-state converters is illustrated, and examples are given     

Markov-modulated birth-death processes

We consider the birth-death process, the parameters of which are determined according to the external environment. The latter is described by a continuous-time Markov chain. In the literature, such processes are designated as Markov-modulated. They allow making such processes time-dependent. Therefore, stochastic models that are based on them prove to correspond closer to the real processes of the Internet, insurance systems, etc. The article expounds the methodology for computing stationary state probabilities for the considered processes. As an example, we analyze a one-line queueing system functioning in a random environment. The numerical data demonstrate the presence of a dependence that significantly alters the efficiency factors of the system.     

A curve-fitting program set for handling of differential pulse polarograms

DP polarograms corresponding to both first- and second-order processes are treated on the basis of approximate equations. Overlapped peaks can also be analysed. BASIC curve-fitting programs running on a APPLE II+ are proposed and tested. Applications to electrochemical kinetics and routine analyses are also considered.     

Probabilistic approach to risk analysis of chemical spills at sea

Risk analysis of chemical spills at sea and their consequences for sea environment are discussed. Mutual interactions between the process of the sea accident initiating events, the process of the sea environment threats, and the process of the sea environment degradation are investigated. To describe these three particular processes, the separate semi-Markov models are built. Furthermore, these models are jointed into one general model of these processes interactions. Moreover, some comments on the method for statistical identification of the considered models are proposed.     

Hardware simulation of semi-Markov and related processes: Part I: a versatile generator

After a brief review and classification of the known generators, this part I of 2 parts paper investigates carefully a new programmable generator of general ordinary renewal processes in discrete time. The generator is based on the concept of failure rate and its implementation is completely digital. The effects of time and amplitude quantization are analyzed in detail. Statistical tests, checking distribution and independence, are partly developed and then applied to numerous examples; results are satisfactory. The distributions of the generated random time intervals are not truncated.Thereafter the generator of renewal processes is extended to allow the hardware simulation of general semi-Markov processes in discrete time. (The generation of related processes will be considered in part II, together with applications.)