Acknowledge-Based Non-Congestion Estimation: An Indirect Queue Management Approach for Concurrent TCP and UDP-Like Flows

This paper presents a new approach for indirect Active Queue Management (indirect AQM) technique called Acknowledge-based Non-Congestion Estimation (ANCE), which employs end-to-end queue management along a network instead to use Explicit Congestion Notification (ECN) bit or to drop packets in the queue. The ANCE performance was compared with Random Early Detection (RED), Control Delay (CoDel), Proportional Integral controller Enhanced (PIE), Explicit Non-Congestion Notification (ENCN), TCP-Jersey and E-DCTCP schemes in a daisychain and in a dumbbell cenario, with TCP flows and UDP-like Networked Control Systems (NCS) flow sharing the same network topology. On the other hand, this paper presents a method for modeling, simulation and verification of communication systems and NCS, using UPPAAL software tool, on which, all network components (channels, routers, transmitters, receivers, plants, and Controllers) were modeled using timed automata making easy a formal verification of the whole modeled system. Simulations and statistical verification show that despite using fewer resources (since ANCE does not need the ECN bit) ANCE presents a very close performance  to ENCN overcoming Drop Tail, RED, CoDel, PIE and E-DCTCP in terms of Integral Time Absolute Error (ITAE) for NCS and fairness for TCP flows. ANCE also attains better performance than RED, PIE, TCP-Jersey and E-DCTCP in terms of throughput for TCP flows

Heuristic Order Reduction of NARX-OBF models Applied to Nonlinear System Identification

Nonlinear system identification concerns the determination of the modelstructure and its parameters. Although the designers often seek the bestmodel for each system, it can be tricky to determine, at the same time, thebest structure and the parameters which optimize the model performance.This paper proposes the use of a Genetic Algorithm, GA, and the Levenberg-Marquardt, LM, method to obtain the model parameters, as well asperform the order reduction of the model. In order to validate the proposedmethodology, the identification of a magnetic levitator, operating in closedloop, was performed. The class NARX-OBF, Nonlinear Auto Regressivewith eXogenous input-Orthonormal Basis Function, was used. The use ofOBF functions aims to reduce the number of terms in NARX models. Oncethe model is found, the order reduction is performed using GA and LM, ina hybrid application, capable of determining the model parameters and reducing the original model order, simultaneously. The results show, considering the inherent trade-of between accuracy and computational effort, theproposed methodology provided an implementation with good mean squareerror, when compared with the full NARX-OBF model

Anthropic Principle Algorithm:A new Heuristic Optimization Meth

Heuristic optimization is an appealing method for solving some en- gineering problems, in which gradient information may not be available, or yet, when the problem presents many minima points. Thus, the goal of this paper is to present a new heuristic algorithm based on the Anthropic Prin- ciple, the Anthropic Principle Algorithm (APA). This algorithm is based on the following idea: the universe developed itself in the exact way to allow the existence of all current things, including life. This idea is very similar to the convergence in an optimization process. Arguing about the merit of the An- thropic Principle is not among the goals of this paper. This principle is treated only as an inspiration for heuristic optimization algorithms. In the final of the paper, some applications of the APA are presented. Classical problems such as Rosenbrock function minimization, system identification examples and min- imization of some benchmark functions are also presented. In order to vali- date the APA’s functionality, a comparison between the APA and the classic heuristic algorithms, Genetic Algorithm (GA) and Particle Swarm Optimiza- tion (PSO) is made. In this comparison, the APA presented better results in majority of tested cases, proving that it has a great potential for application in optimization problems

INTERNET BASED REMOTE LABORATORY: THE LEVEL CONTROL OF THREE COUPLED WATER RESERVOIRS

www.ene.unb.br/lavs

Robust H∞ Output Tracking Control for a Class of Nonlinear Systems with Time-Varying Delays

This paper addresses the H∞ output tracking problem for a class of nonlinear systems subjected to model uncertainties and with interval time-varying delay. The stability of the nonlinear time-delay system is analyzed with a novel delay-interval-dependent Lyapunov–Krasovskii functional. Compared to state-of-the-art criteria for linear and nonlinear time-delay systems, less conservative stability conditions are derived with the introduction of new delay-interval-dependent terms and the exploitation of the delay subintervals size. The proposed analysis considers that the delay derivative is either upper and lower bounded, bounded above only, or unbounded, i.e., no restrictions are cast upon the derivative. Numerical examples are provided to enlighten the importance and advantages of the present criterion which outperforms previous criteria in time-delay systems literature. Also, an additional example is provided to highlight the effectiveness of the proposed H∞ output tracking control design technique for complex nonlinear systems with time-varying delay.Brazil. National Council for Scientific and Technological DevelopmentCoordenação de Aperfeiçoamento de Pessoal de Nível Superio

An Integrated Design Process in Practice: A Nearly Zero Energy Building at the University of Brasília - Brazil

This study aims to present the design experience of LabZERO|UnB, an NZEB building awarded in a public call, that will be built on the University of Brasília campus. The method consisted of defining the design team and the Integrated Design Process (IDP), establishing assumptions and design guidelines, schematic design, initial computer simulations, design development, new simulations, and final calculations for the synthesis of energy performance. As a result, IDP proved to be efficient and underlined the possibility of translating research experiences into practice. The barriers and potentialities related to the coordination of a multidisciplinary team stand out, likewise the organization, planning, and achievement of goals. In the design concept of the 200m2 building, the basic assumption was the adequacy of the architecture to favor the use of passive resources, respecting the local climate, classified as high-altitude tropical climate. Moreover, bioclimatic strategies were used, such as the North/South orientation of main façades, narrow floor plan, limited window-wall ratio, and adequate construction materials, to optimize energy consumption. As a result, the distributed generation of electricity was estimated at 58.29 kWh/m2. a year and the final electricity demand was 34.29 kWh/m2. year. Hence, this process indicates the real possibility of reaching the zero energy balance

An integrated design process in practice : a nearly zero energy building at the University of Brasília - Brazil

This study aims to present the design experience of LabZERO|UnB, an NZEB building awarded in a public call, that will be built on the University of Brasília campus. The method consisted of defining the design team and the Integrated Design Process (IDP), establishing assumptions and design guidelines, schematic design, initial computer simulations, design development, new simulations, and final calculations for the synthesis of energy performance. As a result, IDP proved to be efficient and underlined the possibility of translating research experiences into practice. The barriers and potentialities related to the coordination of a multidisciplinary team stand out, likewise the organization, planning, and achievement of goals. In the design concept of the 200m2 building, the basic assumption was the adequacy of the architecture to favor the use of passive resources, respecting the local climate, classified as high-altitude tropical climate. Moreover, bioclimatic strategies were used, such as the North/South orientation of main façades, narrow floor plan, limited windowwall ratio, and adequate construction materials, to optimize energy consumption. As a result, the distributed generation of electricity was estimated at 58.29 kWh/m2. a year and the final electricity demand was 34.29 kWh/m2. year. Hence, this process indicates the real possibility of reaching the zero energy balance