Incremental verification of co-observability in discrete-event systems

Existing strategies for verifying co-observability, one of the properties that must be satisfied for synthesizing solutions to decentralized supervisory control problems, require the construction of the complete system model. When the system is composed of many subsystems, these monolithic approaches may be impractical due to the state-space explosion problem. To address this issue, we introduce an incremental verification of co-observability approach. Selected subgroups of the system are evaluated individually, until verification of co-observability is complete. The new method is potentially much more efficient than the monolithic approaches, in particular for systems composed of many subsystems, allowing for some intractable state-space explosion problems to be manageable. Properties of this new strategy are presented, along with a corresponding algorithm and an example

Metastable behavior of vortex matter in the electronic transport processes of homogenous superconductors

We study numerically the effect of vortex pinning on the hysteresis voltage-temperature (V-T) loop of vortex matter. It is found that different types of the V-T loops result from different densities of vortex pinning center. An anticlockwise V-T loop is observed for the vortex system with dense pinning centers, whereas a clockwise V-T loop is brought about for vortices with dilute pinning centers. It is shown that the size of the V-T loop becomes smaller for lower experimental speed, higher magnetic field, or weak pinning strength. Our numerical observation is in good agreement with experiments

Extension of Nested Arrays with the Fourth-Order Difference Co-Array Enhancement

To reach a higher number of degrees of freedom by exploiting the fourth-order difference co-array concept, an effective structure extension based on two-level nested arrays is proposed. It increases the number of consecutive lags in the fourth-order difference coarray, and a virtual uniform linear array (ULA) with more sensors and a larger aperture is then generated from the proposed structure, leading to a much higher number of distinguishable sources with a higher accuracy. Compressive sensing based approach is applied for direction-of-arrival (DOA) estimation by vectorizing the fourthorder cumulant matrix of the array, assuming non-Gaussian impinging signals

Authentication codes from ε-ASU hash functions with partially secret keys

An authentication code can be constructed with a family of e-Almost strong universal (e-ASU) hash functions, with the index of hash functions as the authentication key. This paper considers the performance of authentication codes from e-ASU, when the authentication key is only partially secret. We show how to apply the result to privacy amplification against active attacks in the scenario of two independent partially secret strings shared between a sender and a receiver. Keywords: Authentication code; Information theory; Privacy amplification; Unconditional securit

New supersymmetric solutions of N=2, D=5 gauged supergravity with hyperscalars

We construct new supersymmetric solutions, including AdS bubbles, in an N=2 truncation of five-dimensional N=8 gauged supergravity. This particular truncation is given by N=2 gauged supergravity coupled to two vector multiples and three incomplete hypermultiplets, and was originally investigated in the context of obtaining regular AdS bubble geometries with multiple active R-charges. We focus on cohomogeneity-one solutions corresponding to objects with two equal angular momenta and up to three independent R-charges. Curiously, we find a new set of zero and negative mass solitons asymptotic to AdS_5/Z_k, for k \ge 3, which are everywhere regular without closed timelike curves.Comment: Latex 3 times, 42 page

Problems in the classic frequency shift islanding detection methods applied to energy storage converters and a coping strategy

This paper first derives a usable formula based on the parallel R, L, C load and the conclusions from frequency shift islanding detection methods in current literature: the angle by which the total output current of the distributed resources (DR) units leads the point of common coupling (PCC) voltage must be conducted to have the same shifting direction as the load admittance angle during the variation of the frequency. On the basis of the formula and multi-DR operation, the scenarios in which the classic frequency shift methods are applied to energy storage converters are analyzed. The results indicate that the setting of the angle by which the energy storage converter current leads the PCC voltage may need to be modified when running state changes. It results in the problems that the classic methods are not applicable for non-UPF (unity power factor) control and have to distinguish between generation mode and consumption mode for UPF control. On account of the problems, a coping strategy, i.e. an improved method, is proposed. The analyses indicate that the improved method is applicable in every state. The last simulations and experiments confirm the preceding conclusions

BES3 time of flight monitoring system

A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a total of 512 optical fibers, including spares, are used to distribute the light pulses to the Time of Flight counters. The design, operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI

An irregular current injection islanding detection method based on an improved impedance measurement scheme

One class of islanding detection methods, known as impedance measurement-based methods and voltage change monitoring-based methods, are implemented through injecting irregular currents into the network, for which reason they are defined in this paper as irregular current injection methods. This paper indicates that such methods may be affected by distributed generation (DG) unit cut-in events. Although the network impedance change can still be used as a judgment basis for islanding detection, the general impedance measurement scheme cannot separate island events from DG unit cut-in events in multi-DG operation. In view of this, this paper proposes a new islanding detection method based on an improved impedance measurement scheme, i.e., dynamic impedance measurement, which will not be affected by DG unit cut-in events and can further assist some other equipment in islanding detection. The simulations and experiments verify the stated advantages of the new islanding detection method

Impact of Pulp on the Chemical Profile of Mango Wine

The aim of this study was to assess the effect of mango pulp inclusion (which mimicked the maceration stepin grape wine fermentation) on the fermentation dynamics and chemical profile of mango wine, especiallythe volatiles. The growth of Saccharomyces cerevisiae MERIT.ferm was slower in the mango juice with pulp(uncentrifuged juice), with a corresponding slower reduction in °Brix, relative to the juice without pulp(centrifuged juice). The utilisation of glucose, fructose and sucrose was similar in both uncentrifuged andcentrifuged juices, with almost complete consumption. Citric, tartaric, malic, pyruvic and succinic acidwere the major organic acids in the wines fermented from both the uncentrifuged and centrifuged juices.Citric acid decreased slightly in the macerated wine. Tartaric and malic acid decreased in both wines.Pyruvic acid increased slightly and succinic acid remained almost constant in both wines. Monoterpenes,as one of the signature aroma compounds in mango juice, decreased dramatically in both wines, but wereten times higher in the macerated wine. Terpenols were at least four times higher in the macerated wine.The macerated wine also produced higher levels of fusel alcohols and acetate esters compared to the nonmaceratedwine. On the other hand, the non-macerated wine possessed a higher concentration of mediumchainfatty acids and corresponding ethyl esters. This study indicates that the inclusion of pulp in mangowine fermentation would contribute to the aroma complexity

Assessing the damming effects on runoff using a multiple linear regression model: A case study of the Manwan Dam on the Lancang River

AbstractThe Lancang River in Yunnan Province, with a length of 1170km and a 1780-m drop from northwest to southeast, is the most controversial river in southwest China because 14 cascade hydropower stations have been planned on the main waterway. The Manwan Dam, the first of the 14 dams, began operating in 1993, and the associated downstream runoff may have been affected by its construction. To assess this impact, we first investigated the relationships between monthly runoff observed from the Gajiu station and meteorological data obtained from four meteorological gauging stations with a time-lag of 0-3 months over the pre-dam period (1957-2000). Second, we established and validated a multiple linear regression equation employing monthly meteorological and hydrological data during the pre-dam period. Finally, we simulated the monthly runoff after dam construction (1993-2000) using the established equations and assessed the impact of dam construction on runoff by comparing the observed actual monthly runoff with the simulated monthly runoff. Our results suggested a very high hydro-meteorological correlation for the pre-dam period, which opened up the possibility of runoff forecasting. Further, the multiple linear regression equation displayed good simulation performance as coefficient of determination (R2) and the Nash-Suttcliffe coefficient (NS) reached 0.84 and 0.82 respectively. By comparing the observed and the predicted monthly runoff, we found that construction of the Manwan Dam caused a visible disturbance on monthly runoff that, with the disturbance value, displayed a multi-peak fluctuation of up-down variation in the annual hydrologic regime circl