Fluid flow queue models for fixed-mobile network evaluation

A methodology for fast and accurate end-to-end KPI, like throughput and delay, estimation is proposed based on the service-centric traffic flow analysis and the fluid flow queuing model named CURSA-SQ. Mobile network features, like shared medium and mobility, are considered defining the models to be taken into account such as the propagation models and the fluid flow scheduling model. The developed methodology provides accurate computation of these KPIs, while performing orders of magnitude faster than discrete event simulators like ns-3. Finally, this methodology combined to its capacity for performance estimation in MPLS networks enables its application for near real-time converged fixed-mobile networks operation as it is proven in three use case scenarios

Self-Control of Traffic Lights and Vehicle Flows in Urban Road Networks

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks [D. Helbing and P. Moln\'ar, Phys. Eev. E 51 (1995) 4282--4286], we propose a self-organization approach to traffic light control. The problem can be treated as multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as ``green waves'' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes

Actualización de semaforización en Santa Marta Magdalena

En el presente informe estará desarrollado bajo la modalidad de auxiliar de investigación el cual consta del proyecto de investigación. ACTIALIZACION DE LOS SISTEMAS DE SEMAFORIZACION DE LA CIUDAD DE SANTA MARTA EMPLEANDO NUEVAS TECNOLOGIAS. llevado a cabo por el semillero de investigación de la universidad cooperativa de Colombia seccional Santa Marta, donde presentaremos los análisis y estudios necesarios para cumplir con el objetivo general que se ha planteado dentro de este, el cual consta de la caracterización de sistemas tecnológicos implementados en redes de semaforización en países seleccionados a nivel mundial. Con fin de estudiar y analizar cada una de las opciones escogidas y poder implementarlas en la actualización de las redes de semaforización de la ciudad de Santa Marta en pro a mejorar la fluidez y garantizar una seguridad optima en el tráfico principalmente enhoras picos. Este proyecto está compuesto por la introducción donde se establecerá la importancia de este tipo de investigaciones y los beneficios que han tenido en forma general. Tendremos un planteamiento del problema donde se identifica el problema y se delimita el espacio geográfico, así como su espacio temporal a través de la investigación del problema para una posterior formulación de este. Lo que nos lleva a plantar un objetivo general descrito anteriormente y unos objetivos específicos que nos brindan la posibilidad de llegar a una solución óptima. Dentro del informe se establecerá los métodos de investigación utilizados, marco conceptual, métodos de análisis de literatura. Registro de dichos análisis, análisis de resultados, conclusiones.This report will be developed under the modality of research assistant which consists of the research project. UPDATE OF THE SEMPHORIZATION SYSTEMS OF THE CITY OF SANTA MARTA USING NEW TECHNOLOGIES. carried out by the research seedbed of the Santa Marta sectional cooperative university of Colombia, where we will present the analyzes and studies necessary to fulfill the general objective that has been proposed within this, which consists of the characterization of technological systems implemented in traffic light networks in selected countries worldwide. In order to study and analyze each of the chosen options and to be able to implement them in updating the traffic light networks of the city of Santa Marta in order to improve fluidity and guarantee optimal traffic safety, mainly during peak hours. This project consists of the introduction where the importance of this type of research and the benefits they have had in general will be established. We will have an approach to the problem where the problem is identified and the geographical space is delimited, as well as its temporal space through the investigation of the problem for a later formulation of it. Which leads us to plant a general objective described above and specificobjectives that give us the possibility of reaching an optimal solution. The report will establish the research methods used, the conceptual framework, and the literature analysis methods. Record of said analyzes, analysis of results, conclusions.Resumen. -- Abstract. -- Introduccion. -- Planteamiento del problema. -- Formulación del problema. -- Objetivos. -- Objetivo general. -- Objetivos específicos. -- Justificación. -- Marco conceptual. -- De-limitación de la investigación. -- Linea de investigación. -- Delimitaciòn espacial. -- Delimitaciòn temporal. -- Metodología. -- Tipo de investigación. -- Diseño de la investigación. -- Técnica para la recolección de información. -- Análisis de literatura. -- Resultados. -- Conclusiones. -- Recomendaciones. -- Bibliográfica. -

Queues with Congestion-dependent Feedback

This dissertation expands the theory of feedback queueing systems and applies a number of these models to a performance analysis of the Transmission Control Protocol, a flow control protocol commonly used in the Internet

Performance Analysis in IP-Based Industrial Communication Networks

S rostoucím počtem řídicích systémů a jejich distribuovanosti získávájí komunikační sítě na důležitosti a objevují se nové výzkumné trendy. Hlavní problematikou v této oblasti, narozdíl od dřívějších řídicích systémů využívajících dedikovaných komunikačních obvodů, je časově proměnné zpoždění měřicích a řídicích signálů způsobené paketově orientovanými komunikačními prostředky, jako např. Ethernet. Aspekty komunikace v reálném čase byly v těchto sítích již úspěšně vyřešeny. Nicméně, analýzy trendů trhu předpovídají budoucí využití také IP sítí v průmyslové komunikaci pro časově kritickou procesní vyměnu dat. IP komunikace má ovšem pouze omezenou podporu v instrumentaci pro průmyslovou automatizace. Tato výzva byla nedávno technicky vyřešena v rámci projektu Virtual Automation Networks (virtuální automatizační sítě - VAN) zapojením mechanismů kvality služeb (QoS), které jsou schopny zajistit měkkou úroveň komunikace v reálném čase. Předložená dizertační práce se zaměřuje na aspekty výkonnosti reálného času z analytického hlediska a nabízí prostředek pro hodnocení využitelnosti IP komunikace pro budoucí průmyslové aplikace. Hlavním cílem této dizertační práce je vytvoření vhodného modelovacího rámce založeného na network calculus, který pomůže provést worst-case výkonnostní analýzu časového chování IP komunikačních sítí a jejich prvků určených pro budoucí použití v průmyslové automatizaci. V práci byla použita empirická analýza pro určení dominantních faktorů ovlivňujících časového chování síťových zařízení a identifikaci parametrů modelů těchto zařízení. Empirická analýza využívá nástroj TestQoS vyvinutý pro tyto účely. Byla navržena drobná rozšíření rámce network calculus, která byla nutná pro modelování časového chování používaných zařízení. Bylo vytvořeno několik typových modelů zařízení jako výsledek klasifikace různých architektur síťových zařízení a empiricky zjištěných dominantních faktorů. U modelovaných zařízení byla využita nová metoda identifikace parametrů. Práce je zakončena validací časových modelů dvou síťových zařízení (přepínače a směrovače) oproti empirickým pozorováním.With the growing scale of control systems and their distributed nature, communication networks have been gaining importance and new research challenges have been appearing. The major problem, contrary to previously used control systems with dedicated communication circuits, is time-varying delay of control and measurement signals introduced by packet-switched networks, such as Ethernet. The real-time issues in these networks have been tackled by proper adaptations. Nevertheless, market trend analyses foresee also future adoptions of IP-based communication networks in industrial automation for time-critical run-time data exchange. IP-based communication has only a limited support from the existing instrumentation in industrial automation. This challenge has recently been technically tackled within the Virtual Automation Networks (VAN) project by adopting the quality of service (QoS) architecture delivering soft-real-time communication behaviour. This dissertation focuses on the real-time performance aspects from the analytical point of view and provides means for applicability assessment of IP-based communication for future industrial applications. The main objective of this dissertation is establishment of a relevant modelling framework based on network calculus which will assist worst-case performance analysis of temporal behaviour of IP-based communication networks and networking devices intended for future use in industrial automation. Empirical analysis was used to identify dominant factors influencing the temporal performance of networking devices and for model parameter identification. The empirical analysis makes use of the TestQoS tool developed for this purpose. Minor extensions to the network calculus framework were proposed enabling to model the required temporal behaviour of networking devices. Several exemplary models were inferred as a result of classification of different networking device architectures and empirically identified dominant factors. A novel method for parameter identification was used with the modelled devices. Finally, two temporal models of networking devices (a switch and a router) were validated against empirical observations.

Throughput and Yield Improvement for a Continuous Discrete-Product Manufacturing System

A seam-welded steel pipe manufacturing process has mainly four distinct major design and/or operational problems dealing with buffer inventory, cutting tools, pipe sizing and inspection-rework facility. The general objective of this research is to optimally solve these four important problems to improve the throughput and yield of the system at a minimum cost. The first problem of this research finds the optimal buffer capacity of steel strip coils to minimize the maintenance and downtime related costs. The total cost function for this coil feeding system is formulated as a constrained non-linear programming (NLP) problem which is solved with a search algorithm. The second problem aims at finding the optimal tool magazine reload timing, magazine size and the order quantity for the cutting tools. This tool magazine system is formulated as a mixed-integer NLP problem which is solved for minimizing the total cost. The third problem deals with different type of manufacturing defects. The profit function of this problem forms a binary integer NLP problem which involves multiple integrals with several exponential and discrete functions. An exhaustive search method is employed to find the optimum strategy for dealing with the defects and pipe sizing. The fourth problem pertains to the number of servers and floor space allocations for the off-line inspection-rework facility. The total cost function forms an integer NLP structure, which is minimized with a customized search algorithm. In order to judge the impact of the above-mentioned problems, an overall equipment effectiveness (OEE) measure, coined as monetary loss based regression (MLBR) method, is also developed as the fifth problem to assess the performance of the entire manufacturing system. Finally, a numerical simulation of the entire process is conducted to illustrate the applications of the optimum parameters setting and to evaluate the overall effectiveness of the simulated system. The successful improvement of the simulated system supports this research to be implemented in a real manufacturing setup. Different pathways shown here for improving the throughput and yield of industrial systems reflect not only to the improvement of methodologies and techniques but also to the advancement of new technology and national economy