Novel Schmitt trigger with wide temperature range

A novel Schmitt trigger circuit, implemented by a reset-set (RS) trigger and two simple distinct inverters, is proposed. Its trigger levels are determined by two Complementary Metal-Oxide-Semiconductor (CMOS) inverters. Contrast with traditional six transistors Schmitt trigger, its temperature and supply voltage characteristics have been analyzed. These two triggers are applied into relaxation oscillator and the result shows that the proposed one in this paper has better performance over wide temperature range, whose temperature coefficient from 0 to 85 °C is 1/5 of the traditional one. Biography: ZOU Zhige (1975–), male, Ph.D. candidate, research direction: analog and mix-signal IC design.     

On <Emphasis Type="Italic">k</Emphasis>-error linear complexity of some explicit nonlinear pseudorandom sequences

Combining with the research on the linear complexity of explicit nonlinear generators of pseudorandom sequences, we study the stability on linear complexity of two classes of explicit inversive generators and two classes of explicit nonlinear generators. We present some lower bounds in theory on the k-error linear complexity of these explicit generatol＇s, which further improve the cryptographic properties of the corresponding number generators and provide very useful information when they are applied to cryptography.     

Relations between the underground biomass and soil organic carbon and nitrogen of the alpine meadow at the Eastern Margin of the Qinghai-Tibet Plateau

This article, by combining field investigation with laboratorial analysis, studies diverse alpine meadow at the Eastern Margin of the Qinghai-Tibet Plateau for the underground biomass dynamics, vertical distribution of the content of soil carbon and nitrogen, the connection between the biomass and the content of carbon and nitrogen. The studies show that underground biomass in the herb layer of upland meadow is more than that in the terrace meadow, while underground biomass in the upland shrubland is the most. The vertical distribution of underground biomass of each type is obvious as in shape of＂T＂. As to the distribution of the content of soil organic carbon in the three sample grounds, it showed that the deeper the soil the less the content of soil organic carbon. In May, unlike at terrace meadow, the underground biomass and the content of soil organic carbon in positive proportion, such revelation at upland meadow and upland shrubland is not apparent. In July, at upland meadow and terrace meadow the underground biomass and the content of soil total nitrogen in positive proportion, such revelation at upland shrubland is not apparent either.     

Evolutionary computation based optimization of image Zernike moments shape feature vector

The image shape feature can be described by the image Zernike moments. In this paper, we points out the problem that the high dimension image Zernike moments shape feature vector can describe more detail of the original image but has too many elements making trouble for the next image analysis phases. Then the low dimension image Zernike moments shape feature vector should be improved and optimized to describe more detail of the original image. So the optimization algorithm based on evolutionary computation is designed and implemented in this paper to solve this problem. The experimental results demonstrate the feasibility of the optimization algorithm. Biography: LIU Maofu (1977–), male, Associate professor, Ph.D., research direction: image mining, natural language processing.     

Observations of passenger flow and verification of a crowd dynamics model

This paper reports observations of passenger flow in the Wuchang railway station in Wuhan, China during the Chinese Traditional Spring Festival in 2006. The data collected are used to verify a crowd dynamics model previously developed. The crowd dynamics model is based on simulating the global movement of each individual under the influence of the surrounding crowd, and the good agreement between the predictions and observations validates the prediction model. The crowd dynamics model suggests that the crowd movement speed is dominated by two factors： the front-back inter-person effect, and the pedestrian＇s self-motive. The first effect gives logarithmic relationship between the crowd speed and crowd density. The second factor depends on the individual motive driven with which people try to divorce themselves from the control of the crowd movement. The prediction model are helpful to guide the design of public traffic systems for effective crowd dispersal.     

Distribution characteristics of soil organic matter and total nitrogen on the Yajiageng vertical belt,Gongga Mountain around the Dadu River banks

Distribution characteristics of soil organic matter（SOM） and total nitrogen（TN） were studied in different plant communities of the Yajiageng vertical belt in Gongga Mountain around the Dadu River banks. The results show： （1） the contents of SOM and TN of the plant communities gradually decreased with the following order： subalpine coniferous forest （3 027 m）, subalpine meadow （3 873 m）, coniferous broadleaved mixed forest（2 737 m）, subalpine shrub（3 565 m） and treeline（3 564 m）. （2） With soil profile depth increasing, the contents of SOM and TN gradually decreased. For different vegetation types, the contents of SOM and TN in sub-alpine coniferous forest were higher than that of other vegetational types. （3）The ratio of the content of carbon to the content of total nitrogen （Cc/CTN）WaS 13.5-27.6, which was relatively lower than the appropriate Cc/CTN of 25-30, and indicated that the soil in favor of the organic matter decomposed and nutrients released. Cc/CTN in the soil had no correlation with sea level altitude. However, its distribution in the soil x, aried with different vegetation types. （4） Nitrogen in SOM existed mainly in the form of organic nitrogen, and Cc/CTN in the soil was not obvious correlated with SOM and TN.     

Query expansion based on semantics and statistics in Chinese question answering system

In Chinese question answering system, because there is more semantic relation in questions than that in query words, the precision can be improved by expanding query while using natural language questions to retrieve documents. This paper proposes a new approach to query expansion based on semantics and statistics Firstly automatic relevance feedback method is used to generate a candidate expansion word set. Then the expanded query words are selected from the set based on the semantic similarity and seman- tic relevancy between the candidate words and the original words. Experiments show the new approach is effective for Web retrieval and out-performs the conventional expansion approaches.     

EXISTENCE AND UNIQUENESS AND STABILITY OF SOLUTIONS FOR STOCHASTIC IMPULSIVE SYSTEMS

This paper studies the existence, uniqueness, and stability of solutions for stochastic impulsive systems. By employing Lyapunov-like functions, some sufficient conditions of the global existence, uniqueness, and stability of solutions for stochastic impulsive systems are established. Furthermore, the results are specialized to the case of linear stochastic impulsive systems. Finally, some examples are given to illustrate the applications of our theory.     

A novel approach of hybrid genetic optimization with elite ant colony: Application in the modulation recognition

A novel approach (HGO-EAC) for hybrid genetic op-timization (GO) with elite ant colony (EAC) is proposed for the automatic modulation recognition of communication signals,through which we improve the basic ant colony algorithms by referencing elite strategy and present a new fusion strategy for genetic optimization and elite ant colony. This approach is used to train the neural networks as the classifier for modulation. Simula-tion results indicate good performance on an additive white Gaus-sian noise (AWGN) channel,with recognition rate reaching to 70% especially for CW even at signal-to-noise ratios as low as 5 dB. This approach can achieve a high recognition rate for the typical modulations such as CW,4ASK,4FSK,BPSK,and QAM16. Test result shows that it has better performance than BP algorithm and basic ant colony algorithms by achieving faster training and stronger robustness.     

Soundness analysis of compositional model of time-based petri nets

Workflow management systems are widely used in improving the efficiency of business processes.To develop a workflow management system is the key to workflow modeling.In this paper,the compositional time net is presented to model workflow processes on the basis of the analyzing methods of time Petri nets and workflows,and to describe the static relationships and the dynamic semantics of the task of multiple workflow composition.The paper puts more emphasis on checking the soundness of composed workflow,at the same time,combinational problems of non-conditional structure of the compositional time net are introduced and analyzed.A sufficient and necessary condition for determining the soundness of compositional nets is obtained.