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To improve the magnetic stimulation effect, the eccentric trapezoidal magnetic coil (ETM coil) is designed based on the inspiration of special-shaped magnets. The proposed ETM coil consists of two identical coil units and each unit is in the shape of isosceles-trapezoid when projected onto the stimulated target plane. When two coil units are placed adjacent or overlapped, they are referred to as Type I-ETM coil and Type II-ETM coil, respectively. To limit the induced electromagnetic field within a smaller domain, the ETM coil is bent along the symmetrical axis at specific angles. Considering the overheating problem when repetitive stimulation is required, the ETM coil is wound with hollow copper wire and the central hollow part is used to circulate low-temperature deionized water. The finite element analysis method is adopted to obtain the 3D distributions of the induced electromagnetic field generated by ETM coil within the human brain and the internal cooling parameters design is carried out with coupled multi-physical field analysis. Results show that the ETM coil can produce the same stimulation intensity as the traditional FOE coil with less driving current, and it can also significantly improve the intracranial stimulation focalization and reduce the risk of side effects. Meanwhile, because of the internal cooling design, the temperature of the ETM coil could be maintained at room temperature after 3000 effective pulses were applied, while the temperature of the FOE coil exceeds the safe range. To verified our method, an anatomically realistic human head model with different electrical properties assigned to each tissue of the brain is employed in this paper. We also checked the maximum induced charge density on the targeted plane generated by the optimized coil to make sure that it will not cause any induced neurologic damage.

Timed event graphs are a subclass of Petri nets that are commonly applied for modeling and controlling manufacturing systems. In this paper, we investigate the problem of improving the performance of machines (servers) in timed event graphs in order to maximize the firing rate of a system. We show that the logic constraints on the cost of machines and the operation time of machines (firing delay of transitions) can be transformed into linear algebraic constraints. Furthermore, we formulate a mixed integer linear programming problem to maximize the firing rate of the net under a given budget for improving the performance of servers (decreasing the firing delay of transitions) that can provide an optimal solution. Finally, application to an assembly line is presented to show the effectiveness of the developed methodology.

This paper studies the supervisory control problem in Petri nets with unobservable transitions and uncontrollable transitions. Given a Petri net of such a type, a supervisor is designed based on the basis reachability graph in which the set of explicit transitions is a superset of the set of observable transitions. A sensor reduction method is proposed to find a minimal set of observable transitions without compromising the permissiveness. Removal of redundant observable transitions leads to a more compact control structure and a lower cost related to sensor deployment.

In this paper, we propose a method to analyze diagnosability of bounded Petri nets with arbitrary labeling functions. The notion of basis marking is employed to avoid exhaustive enumeration of the set of reachable markings. The novelty consists in removing an assumption that is common in this framework, namely the Petri net system is deadlock-free after the occurrence of any fault. A finite state automaton, called DF-Verifier, is constructed, which allows one to perform diagnosability analysis by looking at some special cycles and states.

Membrane technology, which has such promising features as high efficiency, low-cost and easiness to scale-up, has gained more and more attention in R&D. Its rapid progress urgently needs new technologies of membrane characterization and evaluation for both gas and liquid applications. There are two popular types of membranes, inorganic and polymeric membranes, in current market. For the true separation process, multicomponent gas mixtures need to be studied through the membrane. Totally different behaviors of binary gas permeation between inorganic carbon molecular sieve (CMS) and polymeric polysulfone (PSF) membranes can be revealed by improved time lag technique. Those differences are dependent of their disparate transport mechanisms.

Timed Petri nets are commonly used for modelling and analysis of automated manufacturing systems, including batch or high throughput systems. This paper consider the cycle optimization problem for a deterministic timed weighted marked graphs under infinite server semantics. The problem aims to find an initial marking to minimize the cycle time while the weighted sum of tokens in places is less than or equal to a desired value. We transform a timed weighted marked graph into several equivalent timed marked graphs and present a mixed integer linear programming method which can provide an optimal solution. Meanwhile, two suboptimal methods are proposed to reduce the computational cost.

In multi-sensor spatial registration process, the ill-posedness of the information matrix is the main factor which affects the quality of the registration result. This paper focuses on this problem and makes some progress. For simplicity and without loss of generality, we firstly revisit the least square registration algorithm and analyze the ill-posedness of the information matrix and its reasons. To solve the ill-posed problem, a novel matrix singular value modification algorithm, i.e., the Combination Singular Value Decomposition (CSVD) algorithm is proposed by using the trapezoidal distribution characteristic of singular values of Fisher information matrix. The main contribution of the proposed CSVD algorithm is that it can fully preserve the determinate part of information matrix, while effectively suppressing the uncertain part. Finally, simulation results of two different scenarios show that, the proposed CSVD method can significantly improve the stability and accuracy of the sensor spatial bias estimation.

Timed marked graphs, a special class of Petri nets, are extensively used to model and analyze cyclic manufacturing systems. Weighted marked graphs are convenient to model automated production systems such as robotic work cells or embedded systems. The main problem for designers is to find a trade off between minimizing the cost of the resources and maximizing the system's throughput. It is possible to apply analytical techniques for the average cycle time optimization problem of such systems. The problem consists in finding an initial marking to minimize the average cycle time (i.e., maximize the throughput) while the weighted sum of tokens in places is less than or equal to a given value.

Timed marked graphs (TMGs), a special class of Petri nets, are used to model and analyze cyclic manufacturing systems. Weighted marked graphs (WMGs) are convenient to model systems with bulk services and arrivals. It is possible to apply analytical techniques for the marking optimization problem of such systems. The problem consists in minimizing the cost associated with an initial marking that ensures a given average cycle time. In this paper, we use simulation to compute the average cycle time and give a fast and effective heuristic solution.

A Web service specification can be quite complex, including multiple operations and various kinds of message exchange patterns. In this work, we focus on the problem of restructuring a Web service, which contains a process model inside, preserving at the same time its behavior that is shown to the service user. We provide a behavioral signature model for service restructuring. It is considered for Web services to be choreography equivalence if they conform to the same behavioral signature model. Based on behavioral signature models and graph searching technologies, we provide an algorithm for restructuring the process model from within the service while assuring service choreography equivalence. A case study runs throughout the paper to illustrate the feasibility of our work. We have implemented a prototype to demonstrate and evaluate our approach. Refereed/Peer-reviewed

In view of the limitations of traditional uncorrelated Linear Discriminant Analysis (uLDA) of failure with singular within-scatter matrix and computationally expensive in solving the optimal discriminant vectors for a large and high-dimension dataset, an equivalent uLDA to Linear Discriminant Analysis (IDA) and a algorithm of uLDA based on generalized singular value decomposition is proposed to simply the computation and get over the singularity problem. The classification experimental results of four image and text datasets demonstrate the superiority of our algorithmover other traditional algorithms.

An algorithm is presented on-line absolutely registration two 3D radars using targets that are tracked by both radars. The algorithm estimates and removes radar biases and radar frame orientation errors, For illustrative purposes, the algorithm uses the difference in the position of a target, as reported by the two radars, to compute a set of bias parameters. These bias parameters are then applied to align both radar's track positional data. The registration algorithm is applicable to those situations where there are no radar location errors, the magnitude of the bias errors is small, and these errors do not change with time or very slowly with time.

We proposed and investigated superimposing intensity modulated labels onto high speed frequency modulated payloads in optical label switching packet networks. The transmission performances of 2.5Gb/s ASK label on 40Gb/s CSRZFSK payload is studied for the first time

We proposed and investigated superimposing intensity modulated labels onto high speed frequency modulated payloads in optical label switching packet networks. The transmission performances of 2.5Gb/s ASK label on 40Gb/s 33% RZFSK payload is studied for the first time.

With the rapid distribution of smart grids in China, the power line communications (PLC) have been becoming a potential scheme to transmit data. For any kind of communications system that will be used in a large range, resource allocation is a very important aspect. This paper has analyzed the single-user bit and power allocation model with power self adaptation and speed rate self adaptation based on the constraints of self adaptive OFDM system in the single-phase power line communication, then it has proposed a kind of by bit loading algorithm and carried out simulation analysis under the typical single-user power line channel environment.

A new Photonic crystal fiber structure with five air-holes in the first ring is proposed. This new PCF possess the advantages of fabrication and welding. The effective index, modal field profile and the dispersion (D) characteristics are analyzed by employing the finite element method. It is found that, by adjusting the fabrication parameters, the quinquangular photonic crystal fiber can achieve similar optical properties, even better, be superior to the hexagonal PCF.

The optical structure and working principle of brillouin fiber optic gyroscope was analyzed, the optical components Jones matrix model of brillouin fiber optic gyroscope was established by using Jones matrix optics theory, and the optical transfer matrix model was established based on optical transmission mechanism, the output light intensity expressions of brillouin fiber optic gyroscope and the add-beat frequency caused by optical error were deduced, The influence of main optical components error on the output light of brillouin fiber optic gyroscope was simulated and analyzed. The optical path modeling and error analysis provide a theoretical basis for the design and realization of brillouin fiber optic gyroscope.

Brillouin fiber optic gyroscope has the advantages of simple structure, solid stability, high sensitivity and resolution, high dynamic range and so on, it can be used in plenty of inertial sensor systems. In this paper, frequency stabilization problem of Brillouin fiber-optic gyroscope is researched and analyzed, then a new frequency stabilization technique is proposed, experimental results showed that this program has a good solution to the Brillouin fiber-optic gyro stabilized problem.

A novel scheme of soft-handoff in CDMA system based on a distributed management technology named mobile agent is promoted in this letter. In this method, a mobile agent, which can get channels bandwidth utilization and signal strength information automatically among Base Stations (BSs) and Mobile Switch Centers (MSCs), is created in each BS and MSC. The soft-handoff would be managed by BSs instead of MSCs which could reduce communication times among them, and could solve the “bottle-neck” problem when the handoff is frequent. By analysis and simulation, it can reduce the handoff delay to 55.2% when networks are busy.

Based on the study of the principle of ladder wave modulation in digital closed-loop fiber optic gyroscope, the temperature characteristics of Y waveguide half-wave voltage is analyzed and verified by experiment, then the influences of modulation stability of Y waveguide on fiber optic gyroscope is investigated, and the real-time tracking of compensation method for the modulation instability of Y waveguide is researched and designed. The stability of scale factor, the output interference signal during ladder wave reset period and the zero bias stability of fiber optic gyroscope are tested by comparison experiments whether the real-time tracking of compensation method is adopted. It obtained the conclusion that the modulation stability of Y waveguide is the main reasons affect the accuracy of high-precision fiber optic gyroscope, the accuracy and stability of fiber optic gyroscope has been greatly improved by adopting real-time tracking of compensation method for Y waveguide.

It presents a new type of fiber-optic current sensor —dual-mode fiber optic current sensor, which uses the Gouy phase shift produced by two-mode optical fiber to provide the π / 2 phase bias, and makes use of mode-selective coupler for the structural design. Based on Jones matrix, the mathematical model for dual-mode fiber optic current sensor is established, and the corresponding theoretical analysis and discussion is given finally. Gouy phase shift of two mode fiber can provide a phase bias to improve the system sensitivity and to decrease the system's error. Although the system we designed still have some disadvantages, the system of dual-mode optic fiber current sensor is very simple and flexible, which can be easily to applied to the actual environment in future.

The temperature compensation of fiber optic gyroscope is researched in the viewpoint of the practical engineering application. The temperature characteristics of fiber optic gyroscope are analyzed, and the main factors that caused the temperature drift of gyroscope are definite. Then the temperature experiment is tested, according to the experimental results, summed up that the temperature drift error of fiber optic gyroscope is very close to the temperature change rate of fiber optic coil itself, and also in direct proportion of the temperature difference between the gyroscope shell and the central axis of coil. Based on the principles and steps of least square polynomial fitting method then the temperature drift of fiber optic gyroscope is compensated, and the order problem of polynomial compensation model is researched. The experimental results show that the zero-bias stability of gyroscope can achieve 0.0119 °/h after a 4-order temperature drift polynomial model compensating. The method is simple and reliable, and very suitable for practical engineering applications.

On the base of the research object of the optical system of polarization maintaining interferometric fiber optical gyroscope(IFOG), when the light signal is modulation under +pi/2 square wave signal, an input-output model is established by making use of Jones matrix and coherence matrix. Based on the model mentioned above, theoretic analysis on the polarization noise of the optical system is made, and the polarization error expression in the case of the input low polarization light signal is deduced. Simulation analysis the gyroscope output signal and polarization noise error when the laser source performance parameters change. According to the work mentioned above, we proposed that: to design the optical system of IFOG, we should choose appropriate length of pigtail, select the light source, which the extinction ratio of itpsilas output light have high stability to reduce the zero drift to minimum.

An algorithm is presented to absolutely registration two 3-D sensors using targets that are tracked by both sensors. The algorithm estimates and removes sensor biases and sensor frame orientation errors, For illustrative purposes, the algorithm uses the difference in the position of a target, as reported by the two sensors, to compute a set of bias parameters. These bias parameters are then applied to align both sensorpsilas track positional data. The registration algorithm is applicable to those situations where there are no sensor location errors, the magnitude of the bias errors is small, and these errors do not change with time or very slowly with time.