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In the four generally recognized stages of the life cycle assessment (LCA) community, the life cycle impact assessment (LCIA) has been taken more attention as the most important and controversial phase. How to reflect the spatial characteristics of the environmental impact in the characterization model is in urgent need. First, the midpoint and endpoint categories are selected by analyzing the specialties...
We study the problem of filtering duplicate items over physically distributed data streams to provide clean data for real-time monitoring applications. Existing approaches only filter local duplicates within each stream, and their space and time costs are hardly feasible for high-speed data streams. Based on the space/time efficient data structure Bloom filter, we propose a novel local filtering algorithm...
We find that traditional authentication ways donpsilat act well in MANETs for the features of dynamic topology and non-existence of central facilities in mobile ad hoc networks. This paper presents a distributed trust proving language, which is based on role trust. The solution of constructing credential authentication infrastructure and the problem how to perform automated trust negotiation are also...
In this paper the performance improvement of wireless networks caused by chirp spread spectrum (CSS) as PHY is addressed. Firstly, the bit error rate function is firstly derived theoretically. Then an OPNET modulation curve is created through EMA (external model access) programming using the BER result. By doing this, CSS is introduced into OPNET as an alternate modulation method. Furthermore, simulations...
This paper analyzes the structure and modem scheme of chirp-BOK system. In additive white Gaussian noise channel, an approach of studying the performance of chirp-BOK is presented and the BER-SNR result is evidently improved compared with traditional BOK. Furthermore, the BER of multi-user chirp-BOK system is discussed.
Mobile agents are programs that travel autonomously through a computer network in order to perform some computation or gather information on behalf of a human user or an application. In most applications, the security of mobile agents is of the utmost importance. Obfuscation is a technique in which the mobile code producer enforces the security policy by applying a behavior transformation to the code...
The key problem of designing the operation schedule for public transit lines is to determine the departing time interval. Through studying on influence factors in bus dispatching and passenger flow variety rule in public transit lines, this paper provides a model of controlling departing time interval, which considers both generalized trip cost of passenger and bus enterprise operation cost. The model...
In this paper, a novel series hybrid active power filter based on fundamental magnetic potential self-balance is proposed which consists of three parts: a passive power filter, an active power filter and a series current converter. A LC fundamental series-connected resonance branch is connected in the second side of current converter, then the current converter presents low reactance to fundamental...
A comparative method, which can compensate the material's Verdet constant and linear birefringence variations of Optical Current Transformer (OCT) due to environmental factors, is proposed. The strategy is based on a novel OCT where a permanent magnet is used as reference source. Theoretic analysis is carried out employing matrix optics theory, and the experiment results are presented to show the...
A new type of direct current sensor was studied which includes magnetic potential self-balance circuit and feedback compensation circuit. The characteristics of the device are simple construction, good stability and reliability, and high precision. A simulation model for new direct current sensor is developed. The simulation results of the system have indicated that the accuracy of the DC sensor is...
The eddy current distribution in the shield of a new type CPA is discussed. In this new type CPA, permanent magnet is used to produce excitation field. Because of the permanent magnet, the working mode of this type CPA is different from the conventional CPA that using electric excitation. Therefore the discharge process and the action of the shield should be analyzed to design the parameters of the...
A mathematical model for new direct current sensor based on the magnetic potential self-balance and feedback compensation is developed. Theory for the mathematical model is explained. The simulation results of the system are shown that the accuracy of the dc sensor is better than 0.1%
A new type of direct current sensor is developed which includes two parts: magnetic potential self-balance circuit and feedback compensation circuit. The characteristics of the device are: simple construction, good stability and reliability, and high precision (the error less than 0.1% in range of 40%~100% rated current)
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