Building and Selecting Mobile Agents for Network Management

This paper presents a framework for reusable mobile agents for network management in the sense that they are independent of either particular networks or applications. The framework enables a mobile agent to be composed from two layered components, which are mobile agents. The former is a carrier of the latter over particular networks independent of any management tasks and the latter defines management tasks performed at each host independently of any networks. The framework also offers a mechanism for matchmaking the two components. Since the mechanism is formulated on a process algebra approach, it can accurately select the appropriate itinerary component to perform management tasks at hosts that the tasks want to visit over networks. The framework provides a methodology for easily developing and operating mobile agents for traveling among multiple sub-networks to perform their management tasks at all of the nodes that they visit. This paper also describes the framework, its prototype implementation, and a practical application.

Selection and Setting of an Intelligent Fuzzy Regulator based on Nonlinear Model Simulations of a Helicopter in Hover

Most research on fuzzy regulators has focused on the integrating rules in intelligent control systems. This paper evaluates a fuzzy helicopter regulator for a single-rotor PZL Kania helicopter. Unlike other models which only match stable flight ability, the model presented in this paper attempts to match the links between disturbances and hover conditions. Two simulations were performed to validate the model. In the first simulation, a helicopter was evaluated in a fixed hover position. In the second simulation, model robustness was validated by introducing wind gust. Results, both with the initial and with the modified model demonstrated the viability of the proposed regulator.

A Novel Approach to Charge for IP Services with QoS Support

If the Internet is to become a network supporting differentiated application and transfer services, advanced architectures must be deployed to efficiently support hard Quality of Service (QoS) and usage-based charging. In this paper we present a novel pricing scheme for IP services with guaranteed quality. Our approach is built on the basis of the virtual delay, which is a novel, simple and effective QoS index that describes an advanced IP service. We propose a model to compute the virtual delay from a purely technical point of view, taking into account not only guaranteed performance, but also traffic and system parameters. We then analyze the sensitivity of both the virtual delay and the tariff towards the involved parameters, taking into account both the users’ benefit and the operators’ income. We also extend the pricing model to make it dependent on service demand. Finally, we also present an economic analysis, the aim of which is to establish a model to set the QoS level and the relevant price, taking into account revenue, social fairness, and service availability.

Scalable Network Management Using Lightweight Programmable Network Services

  Although the Simple Network Management Protocol (SNMP) has proven to be a powerful tool for network administrators, it is widely accepted that SNMP does not offer the scalability or the functionality needed to manage large systems of routers and end systems. Active/programmable networks and mobile agent systems have been proposed as alternative network management solutions, offering new functionality and better scalability. Unfortunately, the flexibility and programmability of these (heavyweight) systems comes with its own set of problems, which has prevented them from becoming widely adopted.This paper presents an ultra-lightweight programmable network service called ephemeral state processing (ESP) that can be used to efficiently monitor and collect information from large-scale networks. Although the service offers a limited set of features, the building blocks it does offer can be combined in novel ways to solve a wide range of network management problems while avoiding the problems that plague (heavyweight) active network approaches. The simplicity of ESP allows us to make it available as a general-purpose service that can be used by all packets in the network. We demonstrate the utility of the service by showing how it can be used to efficiently solve common network management problems.

Method for segregation of suspected logical malfunctions in combinatorial discrete devices

Consideration was given to the direct problem of technical diagnosis which lies in determining the technical state of a combinatorial discrete device from the results of testing. The graph and analytical models of behavior of the combinatorial discrete device allowing for the technical state of its elements were presented. A method of segregation of the suspected logical malfunctions under which observable behavior of the combinatorial discrete device is possible was proposed.     

A tracking problem for mechanical systems with delay in control

A problem of tracking for mechanical systems described by nonstationary nonlinear equations is studied at relay control with delay is studied. An approach that makes it possible to solve problems of tracking for mechanical systems whose parameters may continuously vary with time is developed. This approach is based on the transformation of the system and construction of a Lyapunov vector-function with components of the form of vector norm.     

On the method of dynamic programming for linear-quadratic problems of optimal control in hybrid systems

For a sufficiently wide class of the linear hybrid systems, an algorithm of optimal feedback control was proposed. Consideration was given to the hybrid control systems with autonomous switching, as well as the corresponding problems of the hybrid linear-quadratic optimal control based on the recently suggested principle of maximum. Interrelations between the hybrid principle of maximum and the method of dynamic programming for the systems of this class were discussed. The classical formalism was extended, the corresponding Riccati equations were obtained, and discontinuity of the “hybrid” Riccati matrix was proved. The computational aspects of the established theoretical results were considered.     

Approximate solution of two-point boundary value problems for linear in control systems

The two-point boundary value problem for nonlinear systems, linear in unbounded control, is considered. For three-dimensional systems we present a local algorithm of approximate solution to the control problem. On the basis of this algorithm were constructed algorithms of approximate solution to the control problem on the 3-dimensional integral manifold (orbit) of n-dimensional systems with 2-dimensional control. Demonstrating examples are presented.     

Construction of invariant ellipsoids in the stabilization problem for a wheeled robot following a curvilinear path

The synthesis control problem for the plane motion of a wheeled robot is studied. The goal of the control is to bring the robot to an assigned curvilinear trajectory and to stabilize its motion along it in the presence of phase and control constraints. For a synthesized control law, invariant ellipsoids—quadratic approximations of the attraction domains of the target trajectory—are constructed, which allow one to check in the course of the robot motion whether the control law can stabilize motion along the current trajectory segment. To take into account constraints on the control, methods of absolute stability theory are applied. The construction of the invariant ellipsoids reduces to solving a system of linear matrix inequalities.     

Invariance for impulsive control systems

The conventional concepts of invariance are extended in this article to include impulsive control systems represented by measure driven differential inclusions. Invariance conditions and some of their main features are derived. The solution concept plays a critical role in the extension of the conditions for conventional problems to the impulsive control context.     

The investigation algorithm of stability of periodic oscillations in the problem for the Andronov-Hopf bifurcation

A new method for analysis of the stability of free oscillations under the conditions of the Andronov-Hopf bifurcation is suggested. In contrast to commonly applied methods, the algorithm suggested does not require the construction of integral varieties and the transition to normal forms. The algorithm is based on the comparison between the characters of stability of the stationary state of the system and the free oscillations being born. The method suggested enables us to simplify essentially the analysis of stability and obtain simple explicit criteria of stability and instability, and also define the type of bifurcation.     

Method to determine an optimal control in the minimum of resource consumption for the nonlinear stationary systems

An iterative method to solve the nonlinear problems of minimization of resource consumption was proposed. It generalizes to a more general class of nonlinear systems the method of resource minimization for the nonlinear systems with the control-linear right-hand side separated in state and control.     

Gaining insight through case-based explanation

Traditional explanation strategies in machine learning have been dominated by rule and decision tree based approaches. Case-based explanations represent an alternative approach which has inherent advantages in terms of transparency and user acceptability. Case-based explanations are based on a strategy of presenting similar past examples in support of and as justification for recommendations made. The traditional approach to such explanations, of simply supplying the nearest neighbour as an explanation, has been found to have shortcomings. Cases should be selected based on their utility in forming useful explanations. However, the relevance of the explanation case may not be clear to the end user as it is retrieved using domain knowledge which they themselves may not have. In this paper the focus is on a knowledge-light approach to case-based explanations that works by selecting cases based on explanation utility and offering insights into the effects of feature-value differences. In this paper we examine to two such a knowledge-light frameworks for case-based explanation. We look at explanation oriented retrieval (EOR) a strategy which explicitly models explanation utility and also at the knowledge-light explanation framework (KLEF) that uses local logistic regression to support case-based explanation.

Algorithm of multithreshold decoding for Gaussian channels

Major principles of the method of the linear codes multithreshhold decoding as search for the global functional extremum for a great number of variables are considered. It was demonstrated that the multithreshold decoding efficiency is close to the results ensured by the optimum exhaustive search methods. Decoding complexity under software and hardware realizations is evaluated.     

Modernization of one criterion for absolute stability

A new form of a partial frequency criterion of absolute stability for nonlinear automatic control systems is obtained basing on a quadratic transformation of the state vector. As is shown, the obtained criterion is stronger than V.M. Popov’s one. An alternative formulation of the criterion is given in terms excluding the notions of quadratic transformation.     

Two strong equilibria for game problems

The paper presents two new definitions of equilibrium for arbitrary game problems. The new definitions allow finding a unique solution for a significantly wider class of problems.     

Design of robust stable controls for nonlinear objects

We consider a problem of discrete control for a class of nonlinear time-varying objects. Only set estimations for object parameters are available. The aim is to design controls that ensure robust stability of closed-loop systems in a given domain of state space. Since the considered class of objects is large enough not to have a stabilizing control, the proposed design method has to verify at the last step if the obtained conditions of robust stability are satisfied for a nonlinear system “in a given domain.”     

Optimal multilevel organizations for the power cost functions

The problem of maximizing the profit of an economic organization with simultaneous selection of its composition and structure was formulated. Consideration was given to a class of the power cost functions whose parameters reflect the organization environmental characteristics. The optimal organization was analytically established for this case, and the regularities of its variation vs. the environmental conditions were investigated.