Loop transfer recovery design using biased and unbiased controllers

Loop transfer recovery is considered to be a special form of loop sensitivity shaping in this paper. This viewpoint suggests a design strategy which relaxes the requirement that the estimator or controller be unbiased. This strategy is illustrated using a stable, SISO example with a nonminimum phase zero. The approach still faces the design tradeoffs and limitations inherent in all feedback systems including those which apply to nonminimum phase plants. The formulation used here, however, suggests a different approach for dealing with these issues     

Methane selectivity of hydrogenolysis reactions on nickel

Hydrogenolysis of straight-chain pentane and octane was investigated on different nickel catalysts. A pure primary cracking is difficult to observe, because the whole process is a continuous multicracking on the surface of the catalyst. This seems to be a primary process without desorption and readsorption, a hypothesis verified by the very small effect of the space velocity on the selectivities (readsorption of a primary product and its further cracking would have given a strongly retention time-dependent selectivity pattern). The aim was to determine the effect of temperature on the multicracking process and the change of selectivities with temperature and with the liquid hourly space velocity (LHSV). Hydrogenolysis was the only reaction observed. Methane selectivity increased with temperature increase, whereas the selectivities for other hydrocarbons decreased. Methane was mainly produced by primary multicracking. Catalyst carrier had no effect on methane selectivity. It is suggested that the multicracking of a hydrocarbon is mainly primary and not a combination of primary and secondary processes.     

Addition of alcoholes to asymmetric epoxides

Summary Formation of some asymmetric glycoles by the addition of some alcoholes or glycoles to the asymmetric epoxides in the presence of HC10₄ were investigated by ¹³C NMR and the results were simply discussed. It was cleared that the formation of the adducts were led by the electronegativity of the side groups as well as steric nature of the nucleophile involved in the reaction is mostly due to the behavior of the oxonium ions formed as intermediates in the reactions.     

Current-Mode High Output Impedance Multifunction Filters Employing Minimum Number of FTFNs

In this study, five current-mode FTFN-based multifunction filters are proposed, which realize the same transfer functions in ideal case. All circuits employ two capacitors and three resistors. For each circuit R-C:C-R transformation increases the number of realization possibilities to ten. The proposed topologies simultaneously realize three basic filtering functions using minimum number of FTFNs and provide high output impedances that enable easy cascading in current mode. Sensitivity analysis of the filters show that they have low passive sensitivities, and of the filters are insensitive to current tracking errors, furthermore of the filters are insensitive to voltage tracking errors of the FTFNs. The proposed circuits do not require component matching condition except for notch and allpass responses and permit independent adjustment of without disturbing . Experimental and simulation results are given to verify the theoretical analyses.     

COMBINED QUALITATIVE/QUANTITATIVE SIMULATION MODELS OF CONTINUOUS-TIME PROCESSES USING FUZZY INDUCTIVE REASONING TECHNIQUES

Abstract

A new mixed quantitative and qualitative simulation methodology based on fuzzy inductive reasoning is presented. The feasibility of this methodology is demonstrated by means of a simple hydraulic control system. The mechanical and electrical parts of the control system are modeled using differential equations, whereas the hydraulic part is modeled using fuzzy inductive reasoning. The technique is described in detail in the first part of this paper. The example is shown in the second part of the paper. The mixed quantitative and qualitative model is simulated in ACSL, and the simulation results are compared with those obtained from a fully quantitative model. The example was chosen as a simple to describe, yet numerically demanding process whose sole purpose is to prove the concept. Several practical applications of this mixed modeling technique are mentioned in the paper. but their realization has not yet been completed     

The long-run relationship between the spot and futures markets under multiple regime-shifts: Evidence from Turkish derivatives exchange

The paper examines the long-run relationships between the spot and future prices of Istanbul Stock Exchange 30 index (ISE-30) and foreign currencies including the Turkish Lira-US Dollar (TL/USD) and Turkish Lira-Euro (TL/EUR). We analyze the weekly data covering the period from February 9, 2005 to October 17, 2012. Considering structural breaks is important for our analysis since our period consists of recent financial crisis. Therefore, we employ the unit root tests developed by Carrion-i-Silvestre et al. (2009) and the Maki’s (2012) cointegration test allowing for an unknown number of breaks. We find that spot and the futures prices are cointegrated in the long-run after we consider structural breaks in our data. Our results indicate that the markets are efficient.     

Primal Discontinuous Galerkin Methods for Time-Dependent Coupled Surface and Subsurface Flow

This paper introduces and analyzes a numerical method based on discontinuous finite element methods for solving the two-dimensional coupled problem of time-dependent incompressible Navier-Stokes equations with the Darcy equations through Beaver-Joseph-Saffman’s condition on the interface. The proposed method employs Crank-Nicolson discretization in time (which requires one step of a first order scheme namely backward Euler) and primal DG method in space. With the correct assumption on the first time step optimal error estimates are obtained that are high order in space and second order in time.     

Learning-based ship design optimization approach

With the development of computer applications in ship design, optimization, as a powerful approach, has been widely used in the design and analysis process. However, the running time, which often varies from several weeks to months in the current computing environment, has been a bottleneck problem for optimization applications, particularly in the structural design of ships. To speed up the optimization process and adjust the complex design environment, ship designers usually rely on their personal experience to assist the design work. However, traditional experience, which largely depends on the designer’s personal skills, often makes the design quality very sensitive to the experience and decreases the robustness of the final design. This paper proposes a new machine-learning-based ship design optimization approach, which uses machine learning as an effective tool to give direction to optimization and improves the adaptability of optimization to the dynamic design environment. The natural human learning process is introduced into the optimization procedure to improve the efficiency of the algorithm. Q-learning, as an approach of reinforcement learning, is utilized to realize the learning function in the optimization process. The multi-objective particle swarm optimization method, multi-agent system, and CAE software are used to build an integrated optimization system. A bulk carrier structural design optimization was performed as a case study to evaluate the suitability of this method for real-world application.     

A New Approach of Overlay Method for Cognitive SW HARQ System

The aim of this paper is to obtain communication resource based on the overlay method for the secondary user (SU) in the primary communication environment operating in the Stop-and-Wait Hybrid Automatic Repeat Request (SW-HARQ) protocol. Unlike the overlay Cognitive Radio applications in the literature, in this work communication resources have been obtained for the SU in the time period in which the primary user (PU) is active in the channel. Our performance results have shown that a significant amount of sources of communication can be achieved for the SU by evaluating the waiting times in the primary SW HARQ periods, even when the PU is continuously running in the SW HARQ protocol without emptying the channel.