On generalized language equations

AbstractA system of generalized language equations over an alphabet A is a set of n equations in n variables: Xi = Gi(X1,..., Xn), i = 1,...,n, where the Gi are functions from [P(A*)]n into P(A*), i=1,..., n, P(A*) denoting the set of all languages over A. Furthermore the Gi are expressible in terms of set-operations, concatenations, and stars which involve the variable Xi as well as certain mixed languages. In this note we investigate existence and uniqueness of solutions of a certain subclass of generalized language equations. Furthermore we show that a solution is regular if all fixed languages are regular

Succinct representation of regular languages by boolean automata II

AbstractBoolean automata are a generalization of finite automata in the sense that the next state (the result of the transition function, given a state and a letter) is not just a single state (deterministic automata) or a set of states (nondeterministic automata) but a boolean function of the states. Boolean automata accept precisely the regular languages; also, they correspond in a natural way to certain language equation involving complementation as well as to sequential networks. In a previous note we showed that for every n ⩾ 1, there exists a boolean automaton Bn with n states such that the smallest deterministic automaton for the same language has 22n states. In the present note we will show a precisely attainable lower bound on the succinctness of representing regular languages by boolean automata; namely, we will show that, for every n ⩾ 1, there exists a reduced automaton Dn with n states such that the smallest boolean automaton accepting the same language has also n states

Applying genetic algorithms to convoy scheduling

We present the results of our work on applying genetic algorithms combined with a discrete event simulation to the problem of convoy scheduling. We show that this approach can automatically remove conflicts from a convoy schedule thereby providing to the human operator the ability to search for better solutions after an initial conflict free schedule is obtained. We demonstrate that it is feasible to find a conflict free schedule for realistic problems in a few minutes on a common workstation or laptop. The system is currently being integrated into a larger Transportation Information System that regulates highway movement for the militaryIFIP International Conference on Artificial Intelligence in Theory and Practice - Industrial Applications of AIRed de Universidades con Carreras en Informática (RedUNCI

Applying genetic algorithms to convoy scheduling

We present the results of our work on applying genetic algorithms combined with a discrete event simulation to the problem of convoy scheduling. We show that this approach can automatically remove conflicts from a convoy schedule thereby providing to the human operator the ability to search for better solutions after an initial conflict free schedule is obtained. We demonstrate that it is feasible to find a conflict free schedule for realistic problems in a few minutes on a common workstation or laptop. The system is currently being integrated into a larger Transportation Information System that regulates highway movement for the militaryIFIP International Conference on Artificial Intelligence in Theory and Practice - Industrial Applications of AIRed de Universidades con Carreras en Informática (RedUNCI

Safeguarding the transmission of biometric measurements used for authenticating individuals

Various biometric measurements can be used to establish the identity of individuals. Common to many of them is the fact that a significant amount of information is collected and transmitted; this information is then used to compare the captured biometric data with the previously recorded information identifying a particular individual. If the two pieces of information are similar, it is assumed that the identification is carried out correctly. An important problem in this process is the safeguarding of the transmission of the captured information. In many cases, it cannot be assumed that the channel over which this information is transmitted is secure. Therefore it is crucial that the process be viable even if the channel is insecure. We outline an approach that ensures the security and integrity of this process. We demonstrate that this approach is highly effective in that it requires only minimal additional storage capacity and virtually no additional processing capacity to be functional. Support of this research under NSF grants DUE 0313880, SCI 0453498, and OISE 0519316 is acknowledged.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

Performance Evaluation of Load-Balanced Routing via Bounded Randomization

Future computer networks are expected to carry bursty traffic. Shortest-path routing protocols such as OSPF and RIP have t he disadvantage of causing bottlenecks due to their inherent single-path routing. That is, the uniformly selected shortest path between a source and a destination may become highly congested even when many other paths have low utilization. We propose a family of routing schemes that distribute data traffic over the whole network via bounded randomization; in this way, they remove bottlenecks and consequently improve network performance. For each data message to be sent from a source s to a destination d, each of the proposed routing protocols randomly choose an intermediate node e from a selected set of network nodes, and routes the data message along a shortest path from s to e. Then, it routes the data message via a shortest path from e to d. Intuitively, we would expect that this increase the effective bandwidth between each source-destination pair. Our simulation results indicate that the family of proposed load-balanced routing protocols distribute traffic evenly over the whole network and, in consequence, increases network performance with respect to throughput, message loss, message delay and link utilization. Moreover, implementing our scheme requires only a simple extension to any shortest-path routing protocol

A cache memory system based on a dynamic/adaptive replacement approach

En este trabajo, nosotros proponemos un sistema de memoria cache basado en un esquema de reemplazo adaptativo, el cual formaría parte del Sistema Manejador de la Memoria Virtual de un Sistema Operativo. Nosotros usamos un simulador de eventos discretos para comparar nuestro enfoque con trabajos previos. Nuestro esquema de reemplazo adaptativo esta basado en varias propiedades del sistema y de las aplicaciones, para estimar/escoger la mejor política de reemplazo. Nosotros definidos un valor de prioridad de reemplazo a cada bloque de la memoria cache, según el conjunto de propiedades del sistema y de las aplicaciones, para seleccionar cual bloque eliminar. El objetivo es proveer un uso efectivo de la memoria cache y un buen rendimiento para las aplicaciones.Palabras Claves: Sistema de Manejo de Memoria, Memoria Cache, Evaluación de Rendimiento

Applying genetic algorithms to convoy scheduling

We present the results of our work on applying genetic algorithms combined with a discrete event simulation to the problem of convoy scheduling. We show that this approach can automatically remove conflicts from a convoy schedule thereby providing to the human operator the ability to search for better solutions after an initial conflict free schedule is obtained. We demonstrate that it is feasible to find a conflict free schedule for realistic problems in a few minutes on a common workstation or laptop. The system is currently being integrated into a larger Transportation Information System that regulates highway movement for the militaryIFIP International Conference on Artificial Intelligence in Theory and Practice - Industrial Applications of AIRed de Universidades con Carreras en Informática (RedUNCI

The Comparison Of Dome And HMD Delivery Systems: A Case Study

For effective astronaut training applications, choosing the right display devices to present images is crucial. In order to assess what devices are appropriate, it is important to design a successful virtual environment for a comparison study of the display devices. We present a comprehensive system, a Virtual environment testbed (VET), for the comparison of Dome and Head Mounted Display (HMD) systems on an SGI Onyx workstation. By writing codelets, we allow a variety of virtual scenarios and subjects' information to be loaded without programming or changing the code. This is part of an ongoing research project conducted by the NASA / JSC

A Virtual Environment System for the Comparison of Dome and HMD Systems

For effective astronaut training applications, choosing the right display devices to present images is crucial. In order to assess what devices are appropriate, it is important to design a successful virtual environment for a comparison study of the display devices. We present a comprehensive system for the comparison of Dome and head-mounted display (HMD) systems. In particular, we address interactions techniques and playback environments