In order to ensure the stability of temperature of the blackbody radiation source, a high-performance, high-precision temperature control system is designed. This system is based on the thermo-electric cooler (TEC) wh...
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In order to ensure the stability of temperature of the blackbody radiation source, a high-performance, high-precision temperature control system is designed. This system is based on the thermo-electric cooler (TEC) which is controlled by ADN8830 automatically. The temperature of the blackbody radiation source is sensed by the Pt100 thermistor, and then the temperature signal is converted into the voltage signal by the temperature transmitter to ADN8830. The PID closed feedback loop is adopted for the temperature controlling. Through the test of the designed temperature control system, the result shows that the set-up time of this system is about 340 s and the temperature control accuracy is ±0.02°C.
Dual satellite TDOA/FDOA localization scheme has problems of multiple ambiguous solutions and poor localization results in the sub-satellite area along the dual satellite baseline direction. Passive localization using...
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Dual satellite TDOA/FDOA localization scheme has problems of multiple ambiguous solutions and poor localization results in the sub-satellite area along the dual satellite baseline direction. Passive localization using TDOA and FDOA measurements usually does not have direct solution and requires numerical methods to determine the emitter's geolocation. We suggest a satellite passive localization method fusing the TDOA/FDOA/AOA measurements based on particle swarm optimization(PSO), which provides an evolutionary computation method to solve the nonlinear optimal problem. To be more close to the practical use, the WGS-84 earth model is adopted in this work. However, PSO can not be directly applied to geolocation problem due to the nonlinear constraint of earth surface. We examined a PSO based method which let the particle swarm fly on the earth surface. Computer simulation results show the effectiveness of the new localization method.
The design based on avalanche photo diode (APD) is described in this paper to provide a extract the weak signal from the noise. The amplifying circuit based on negative feedback current input can realize high sensitiv...
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The design based on avalanche photo diode (APD) is described in this paper to provide a extract the weak signal from the noise. The amplifying circuit based on negative feedback current input can realize high sensitivity, low noise amplifying, and the OPA657 chip is selected as the pre-amplifier. MAX280 active low-pass filter is used to suppress high frequency noise effectively and the output signal to noise ratio (SNR) is improved by 5 times. The theory analysis and the experiment results show that the minimum detection power of the circuit is about 7.9 nW to the light of 980 nm.
An effective text representation scheme dominates the performance of text categorization system. However, based on the assumption of independent terms, the traditional schemes which tediously use term frequency （TF）...
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An effective text representation scheme dominates the performance of text categorization system. However, based on the assumption of independent terms, the traditional schemes which tediously use term frequency （TF） and document frequency （DF） are insufficient for capturing enough information of a document and result in poor performance. To overcome this limitation, we investigate exploring the relationships between different terms of the same class tendency and the way of measuring the importance of a repetitive term in a document. In this paper, a group of novel term weighting factors are proposed to enhance the category contribution for each term. Then, based on a novel strategy of generating passages from document, we present two schemes, the weighted co-contributions of different terms corresponding to the class tendency and the weighted co-contributions for each term in different passages, to achieve improvements on text representation. The prior scheme works in a dimensionality reduction mode while the second one runs in the conventional way. By employing the support vector machine （SVM） classifier, experiments on four benchmark corpora show that the proposed schemes could achieve a consistent better performance than the conventional methods in both efficiency and accuracy. Further analysis also confirms some promising directions for the future works.
For a complex network, detecting the key links is of great importance. In recent years, many community detecting algorithms have been proposed, which have both advantages and disadvantages. In this paper, we propose a...
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ISBN:
(纸本)9781479913930
For a complex network, detecting the key links is of great importance. In recent years, many community detecting algorithms have been proposed, which have both advantages and disadvantages. In this paper, we propose and compare some classical community detecting algorithms and choose the best one of them to detect the key links of the complex network.
Through introducing Koch fractal theory, an ordinary AMC structure and broadband Koch fractal AMC ground planes are designed and compared. The bandwidth and performance improvement of the fractal AMC ground plane are ...
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In this paper, frequency selective surface (FSS) with relative zero-phase shift is realized and characterized. The FSS unit cell is designed by adding cross aperture to the cross loop slot at its center, and the four ...
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In this paper, a zero index metamaterial lens (ZIML) based on Z-shaped meta-atom is proposed to achieve directive emission. Z-shaped meta-atom is implement as the unit cell of the ZIML to achieve near zero permittivit...
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A broadband sleeve antenna with very small ground has been presented based on impedance matching network and resistive load. The VSWR of the proposed antenna is less than 2 from 0.17GHz to 0.52GHz. The efficiency of t...
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Multi-hop time synchronization in wireless sensor networks (WSNs) is often time-consuming and error-prone due to random time-stamp delays for MAC layer access and unstable clocks of intermediate nodes. Constructive in...
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