422,972 research outputs found

    Dependent Types for Nominal Terms with Atom Substitutions

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    Nominal terms are an extended first-order language for specifying and verifying properties of syntax with binding. Founded upon the semantics of nominal sets, the success of nominal terms with regard to systems of equational reasoning is already well established. This work first extends the untyped language of nominal terms with a notion of non-capturing atom substitution for object-level names and then proposes a dependent type system for this extended language. Both these contributions are intended to serve as a prelude to a future nominal logical framework based upon nominal equational reasoning and thus an extended example is given to demonstrate that this system is capable of encoding various other formal systems of interest

    C-system of a module over a monad on sets

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    This is the second paper in a series that aims to provide mathematical descriptions of objects and constructions related to the first few steps of the semantical theory of dependent type systems. We construct for any pair (R,LM)(R,LM), where RR is a monad on sets and LMLM is a left module over RR, a C-system (contextual category) CC(R,LM)CC(R,LM) and describe a class of sub-quotients of CC(R,LM)CC(R,LM) in terms of objects directly constructed from RR and LMLM. In the special case of the monads of expressions associated with nominal signatures this construction gives the C-systems of general dependent type theories when they are specified by collections of judgements of the four standard kinds

    A Popov Stability Condition for Uncertain Linear Quantum Systems

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    This paper considers a Popov type approach to the problem of robust stability for a class of uncertain linear quantum systems subject to unknown perturbations in the system Hamiltonian. A general stability result is given for a general class of perturbations to the system Hamiltonian. Then, the special case of a nominal linear quantum system is considered with quadratic perturbations to the system Hamiltonian. In this case, a robust stability condition is given in terms of a frequency domain condition which is of the same form as the standard Popov stability condition.Comment: A shortened version to appear in the proceedings of the 2013 American Control Conferenc

    Performance of optimal hierarchical type 2 fuzzy controller for load–frequency system with production rate limitation and governor dead band

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    AbstractControlling load–frequency is regarded as one of the most important control-related issues in design and exploitation of power systems. Permanent frequency deviation from nominal value directly affects exploitation and reliability of power system. Too much frequency deviation may cause damage to equipment, reduction of network loads efficiency, creation of overload on communication lines and stimulation of network protection tools, and in some unfavorable circumstances, may cause the network collapse. So, it is of great importance to maintain the frequency at its nominal value.It would be useful to make use of the type 2 fuzzy in modeling of uncertainties in systems which are uncertain. In the present article, first, the simplified 4-block type-2 fuzzy has been used for modeling the fuzzy system. Then, fuzzy system regulations are reduced by 33% with the help of hierarchy fuzzy structure. The simplified type-2 fuzzy controller is optimized using the Cuckoo algorithm. Eventually, the performance of the proposed controller is compared to the Mamdani fuzzy controller in terms of the ISE, ITSE, and RMS criteria

    Longitudinal limitations in the PS complex for the generation of the LHC proton Beam

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    The nominal operating scheme for feeding LHC with protons [1] makes use of the PS injectors complex. Many new manipulations are used in the longitudinal phase plane. The radio-frequency systems of the PS Booster (PSB) operate on harmonics 1 and 2, harmonic 10 being used for controlled emittance blow-up during acceleration. The PS accelerates on harmonics 8 and 16. Debunching takes place at 26 GeV followed by rebunching on harmonic 84 (40 MHz) and bunch compression before ejection to the SPS. Although certainly capable of providing the nominal type of beam, these processes are marginal in terms of performance and have not all been experimentally demonstrated. These limitations are described together with possible improvements. New directions of investigation including the SPS are encouraged

    A fully digital power supply noise thermometer

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    Power Supply Noise (PSN) is one of the main concerns in scaled technology circuits, both if performance reliability must be assured and if power supply is to be dynamically reduced for dissipation regulation. In this paper we propose a new system for digitally sensing Power Supply and Ground levels that can be both transferred to the output for verification purposes and used by a control block within the circuit under test (CUT) for the activation of power aware policies. The sensor system shows very low overhead in terms of power and area, and works at the nominal CUT frequency. It allows to change on-site the Power Supply and Ground ranges to be sensed and, after a fine tuning, can be arranged for a process variation aware measures. This sensor is fully digital and standard cell based and can be used for every type of architecture on a systematic basis for PSN measure as scan chains are for fault verification. It thus represents a change of paradigm in the way in which PSN measure systems are thought nowaday

    Welfare effects of fixed and percentage-expressed child support awards

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    Over the last decade a large number of states have significantly altered their legal statutes concerning the disposition of divorce cases involving children. In particular, many states have increasingly employed percentage-expressed orders in which child support obligations in a given period are determined as a proportion of the contemporaneous income of the noncustodial parent. In contrast to more traditional systems in which obligations were set in fixed nominal terms at the time of the divorce settlement and were infrequently (or never) updated, the dynamic system has the advantages of allowing children (and the custodial parent) an opportunity to share in the general income gains experienced by the noncustodial parent over the life cycle and of possibly alleviating some noncompliance problems. In this paper we conduct a rather extensive theory-based empirical investigation of the effects of these systems on the income process for divorced fathers and the child support transfer decision. We estimate a flexible statistical model for the income- generation process for divorced fathers which encompasses the period both before and after the divorce. We interpret the estimates from this model to indicate small behavioral effects of the type of order on postdivorce income, but nonrandom assignment (in terms of the means and variances of predivorce income) into the percentage-expressed-order state. Our analysis of the effects of the order type on child support transfers is divided into two parts. In the first, a "reduced form" analysis, we investigate whether or not the divorced father's regime defined as the order type and withholding status can be considered exogenous vis-a-vis the transfer decision, and examine the relative effects of the various regimes on the transfer rate. We further attempt to investigate order-type effects on compliance in the context of a structural model of the compliance decision. The results of the two analyses are for the most part consistent. Percentage orders are generally associated with lower compliance rates, though withholding tends to alleviate the problem. The highest compliance rates are associated with fixed orders coupled with withholding.

    Bio-Inspired Mechanism for Aircraft Assessment Under Upset Conditions

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    Based on the artificial immune systems paradigm and a hierarchical multi-self strategy, a set of algorithms for aircraft sub-systems failure detection, identification, evaluation and flight envelope estimation has been developed and implemented. Data from a six degrees-of-freedom flight simulator were used to define a large set of 2-dimensional self/non-self projections as well as for the generation of antibodies and identifiers designated for health assessment of an aircraft under upset conditions. The methodology presented in this paper classifies and quantifies the type and severity of a broad number of aircraft actuators, sensors, engine and structural component failures. In addition, the impact of these upset conditions on the flight envelope is estimated using nominal test data. Based on immune negative and positive selection mechanisms, a heuristic selection of sub-selves and the formulation of a mapping- based algorithm capable of selectively capturing the dynamic fingerprint of upset conditions is implemented. The performance of the approach is assessed in terms of detection and identification rates, false alarms, and correct prediction of flight envelope reduction with respect to specific states. Furthermore, this methodology is implemented in flight test by using an unmanned aerial vehicle subjected to nominal and four different abnormal flight conditions instrumented with a low cost microcontroller

    Thermodynamic, economic and environmental assessment of energy systems including the use of gas from manure fermentation in the context of the Spanish potential

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    One of the prospective technologies that can be used for energy generation in distributed systems is based on biogas production, usually involving fermentation of various types of biomass and waste. This article aims to bring novelty on the analysis of this type of systems, joining together thermodynamic, economic and environmental aspects for a cross-cutting evaluation of the proposed solutions. The analysis is made for Spain, for which such a solution is very promising due to availability of the feedstock. A detailed simulation model of the proposed system in two different cases was built in Aspen Plus software and Visual Basic for Applications. Case 1 involves production of biogas in manure fermentation process, its upgrading (cleaning and removal of CO2 from the gas) and injection to the grid. Case 2 assumes combustion of the biogas in gas engine to produce electricity and heat that can be used locally and/or sold to the grid. Thermodynamic assessment of these two cases was made to determine the most important parameters and evaluation indices. The results served as input values for the economic analysis and environmental evaluation through Life Cycle Assessment of the energy systems. The results show that the analysed technologies have potential to produce high-value products based on low-quality biomass. Economic evaluation determined the break-even price of biomethane (Case 1) and electricity (Case 2), which for the nominal assumptions reach the values of 16.77 €/GJ and 28.92 €/GJ, respectively. In terms of environmental assessment the system with the use of biogas in gas engine presents around three times better environmental profile than Case 1 in the two categories evaluated, i.e., carbon and energy footprint.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkƂodowska-Curie grant agreement No 799439. Dr. Martín-Gamboa states that thanks are due to FCT/MCTES for the financial support to CESAM (UID/AMB/50017/2019), through national funds
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