A comprehensive analysis of the carrier-induced FM response of DFB lasers is given. Experimentally it is found that the FM response can sometimes vary strongly from chip to chip. In a number of cases anomalies either ...
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A comprehensive analysis of the carrier-induced FM response of DFB lasers is given. Experimentally it is found that the FM response can sometimes vary strongly from chip to chip. In a number of cases anomalies either as a function of frequency or as a function of bias are observed. Theoretically, a dynamic model which includes spectral as well as longitudinal spatial hole burning is presented. The main feature of the model is that local variations of the Bragg wavelength caused by hole burning are rigorously and self-consistently taken into account. By comparing the experimental results with theoretical calculations, it is shown that in DFB lasers, spatial hole burning is an important phenomenon. The model confirms that the dynamic (FM) behavior can vary from DFB chip to DFB chip. The model shows that spatial hole burning is indeed the dominant factor which induces the anomalies that are found experimentally in the FM response.< >
This paper summarizes the results from a number of different voltage sag investigations. These investigations involve characterizing the voltage sag performance at a customer facility and evaluating equipment sensitiv...
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This paper summarizes the results from a number of different voltage sag investigations. These investigations involve characterizing the voltage sag performance at a customer facility and evaluating equipment sensitivity to different voltage sag magnitudes and durations. Possible solutions to voltage sag sensitivity problems are also described.
A cognitive antenna selection strategy for multi-in multi-out (MIMO) imaging radar is proposed in this article. The basic idea of our strategy relies on the dynamic selection of the antenna location according to the f...
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A cognitive antenna selection strategy for multi-in multi-out (MIMO) imaging radar is proposed in this article. The basic idea of our strategy relies on the dynamic selection of the antenna location according to the feedback information to enhance the image quality and reduce the computational burden simultaneously. The aim of our strategy is to indirectly minimize the mean squared error associated with the amplitudes and positions of the strong scattering centers of the target through the frame potential. Specifically, it is assumed that the imaging process is initially performed via a conventional uniform linear array/random sparse array of collocated MIMO radar;hence, based on the collected data, an initial image of the target is derived (perception). Then, the accuracy of low-resolution images is enhanced progressively according to the cognitive paradigm via a specific antenna location selection at the next transmission (action). Benefit from the enhanced accuracy, the support area of targets can be estimated to reduce the dimension of the undersampling matrix and, finally, the computational burden in the subsequent high-resolution image reconstruction process is reduced. The simulation results highlight the capabilities of our cognitive approach to provide more interesting benefits in imaging than the random selection strategy and demonstrate the enhanced imaging performance of cognitive sparse MIMO array under the condition of limited antennas and noise.
The most effective trends in the computer-aided design of software (S) for built-in control computers (BCCs) for aircraft and spacecraft control systems are examined. The principles of software design that are adaptab...
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The most effective trends in the computer-aided design of software (S) for built-in control computers (BCCs) for aircraft and spacecraft control systems are examined. The principles of software design that are adaptable to manufacture are examined. The ''Krus'' engineering tools environment (ETE), which makes it possible to improve labor productivity in the design of BCC software by a factor of 1.5-2 is examined. An a posteriori statistical criterion for the debuggability of software programs is examined together with the requirements imposed on an intelligent user-software debugging system interface.
Case-based reasoning recognizes the power of individual solutions, while task-specific architectures take advantage of commonalities among groups of solutions. The key to combining the two lies in solving the riddle o...
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Case-based reasoning recognizes the power of individual solutions, while task-specific architectures take advantage of commonalities among groups of solutions. The key to combining the two lies in solving the riddle of case-based reasoning: how can uninterpreted cases be indexed for future use?.
With the recent development of powerful workstations integrated in local area networks, the need for distributed applications has increased significantly. This way, formerly autonomous applications of areas like compu...
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With the recent development of powerful workstations integrated in local area networks, the need for distributed applications has increased significantly. This way, formerly autonomous applications of areas like computer integrated manufacturing or office automation can be integrated to cooperating entities. However, the development of these kinds of applications is still not well supported.
The paper describes an object-oriented softwareengineering approach for distributed applications. The approach is centered around a wide-spectrum design language used as a common base for a set of workbenches. The associated tools are focusing on problems related to distribution and complexity of applications. Life-cycle spanning development support shall be provided by the environment.
A new theoretical approach to the description of state-logic relations is presented, which applies to linear as well as nonlinear autonomous networks. A formal link, based on a matrix algorithm, is found between the i...
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A new theoretical approach to the description of state-logic relations is presented, which applies to linear as well as nonlinear autonomous networks. A formal link, based on a matrix algorithm, is found between the internal logic of the network and its terminal behavior. The application of matrix algebra is the most attractive and encouraging aspect of this theory, in view of possible systematic minimization procedures.
This paper addresses a ratembased feedback approach to congestion control in packet switching networks where sources adjust their transmission rate in response to feedback information from the network nodes. Specifica...
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This paper addresses a ratembased feedback approach to congestion control in packet switching networks where sources adjust their transmission rate in response to feedback information from the network nodes. Specifically, a controller structure and system architecture are introduced and the analysis of the resulting closed loop system is presented. Conditions for asymptotic stability are derived. A design technique for the controller gains is developed and an illustrative example is considered. The results show that, under appropriately selected control gains, a stable (nonoscillatory) operation of store-and-forward packet switching networks with feedback congestion control is possible.
The authors summarize four years of single-event-upset test results on a wide range of devices and technologies using Californium-252 having an average linear energy transfer of 43 MeV/(mg/cm/sup 2/). Sensitivity vari...
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The authors summarize four years of single-event-upset test results on a wide range of devices and technologies using Californium-252 having an average linear energy transfer of 43 MeV/(mg/cm/sup 2/). Sensitivity variations are highlighted, particularly for nominally identical devices. The significance of the testing and test data with respect to recent devices and technologies is discussed.< >
This article investigates the inaccuracies of identifying parameters for a single-phase transformer. In addition, in this article, two new transformer parameter estimation algorithms based on recently developed optimi...
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This article investigates the inaccuracies of identifying parameters for a single-phase transformer. In addition, in this article, two new transformer parameter estimation algorithms based on recently developed optimization techniques, as well as an objective function, are proposed for the transformer parameter estimation to improve the estimation process and prevent inaccuracies and parameters mismatch with real parameters of the transformer. The proposed algorithms utilize manta ray foraging optimization and chaotic manta ray foraging optimization methods for the estimation of transformer parameters. Unlike the previously proposed methods in the literature, the proposed objective function in this article includes no-load losses in the estimation process. For the matter of comparison, the estimated parameters obtained by using the proposed optimization techniques and objective function are compared with the corresponding values obtained using the classical test procedure recommended by IEEE, as well as with the corresponding values obtained using the previously introduced methods in the literature. The usage of the proposed objective function guarantees the representation of the real copper and no-load losses in the estimated transformer parameters and ensures that the estimated transformer output characteristics are in very good agreement with the experimentally obtained curves. To prove the effectiveness of the proposed parameter estimation algorithms, experimental parameters identification tests are implemented, and the experimentally identified transformer parameters are compared with the estimated parameters and their correlation is studied.
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