Applied Mechanics and Materials Vol. 643

Abstract: Recently, the concept of software radar has been proposed. The wide application of the digital technology has become a trend. With the development of modern radar system, the system requires higher and higher performance to the radar receiver. The technology of digital receiver has become an effective implementation method for high-accuracy and wide-band radar receiving systems. However, most of the digital receiver can only receive one wide-band signal with one center frequency. A multi-frequency digital receiver which can receive several center frequencies of signal simultaneously [1] is discussed in this paper. We also describe the theory and the design about digital receiver, introduce digital downconversion (DDC), FIR and decimation, digital beam forming and channel calibration. Based on the research, a realization of multi-frequency digital receiver based on FPGA is put forward. The analysis and simulation is made and the result shows the design of great performance.

Abstract: Using the derivative of Boolean functions and the e-derivative defined by ourselves as research tools, we discuss the relationship among a variety of cryptographic properties of the weight symmetric H Boolean functions in the range of the weight with the existence of H Boolean functions. We also study algebraic immunity and correlation immunity of the weight symmetric H Boolean functions and the balanced H Boolean functions. We obtain that the weight symmetric H Boolean function should have the same algebraic immunity, correlation immunity, propagation degree and nonlinearity. Besides, we determine that there exist several kinds of H Boolean functions with resilient, algebraic immunity and optimal algebraic immunity. The above results not only provide a theoretical basis for reducing nearly half of workload when studying the cryptographic properties of H Boolean function, but also provide a new research method for the study of secure cryptographic property of Boolean functions. Such researches are important in cryptographic primitive designs.

Abstract: Using the derivative of the Boolean function and the e-derivative defined by ourselves as research tools and deeply into the internal structure of Boolean, we study the issues of the analysis and judgment of balance for Boolean functions. We get that the linear functions and the nonzero derivative of the product of two linear functions are balanced functions, and the product of two linear functions are not balanced functions. We also obtain the quadratic homogeneous Booleans are not all balanced function. Besides, we deduce the theorem which determine the sum of linear function and balanced function whether it is a balanced function. What is more, the features of balance of Boolean functions can be reflected easily and effectively by e-derivative.

Abstract: Smart TV terminals have become an emerging platform for both personal and business application. Security for applications running on smart TV terminals is important .In this paper we present TVOS, a new OS for enabling high assurance applications to run on smart TV terminal securely. Our main contributions are a new OS architecture and our use of formal methods for proving key security invariants about our implementation. As an operating system, TVOS is still relatively young. To analyze its security and tested its performance. Our evaluation shows that the performance of TVOS is comparable to an Android-based system. In one test, we ran the same web browser on TVOS and on an Android-based system and found that TVOS adds overhead on average to the page load latency time for nine popular web sites.

Abstract: It is important to research the application of virtual world used in special education to promote the informatization of special education. Firstly, this paper analyzes the current problems faced by special education. Secondly, an application structure of virtual world for special education is designed based on Second Life. Finally, its advantages and the likely problems for Educators are discussed. This research can provide some reference for educators who should bring virtual world into special education classroom in future.

Abstract: As culture exhibition research platform and culture transmitting education and teaching platform, Wu Culture Corner plays a very important role in handing down and developing Wu culture, accelerating school culture construction and human resources training. However, with the vapid development of scientific research and teaching, the existing condition can no longer meet the increasing needs of numerous teachers and students. Use digital media technology to digitalize Wu Culture Corner, and based on which digital Wu Culture Corner can be constructed, and put it in throughout the teaching process, so that it can provide better serve in protecting and studying, publicizing and educating, culture transmitting. The constructing of Digital Wu Culture Corner plays a very important role in exhibiting Wu culture kernel, meeting the demands of teachers and students in teaching and studying, following the pace of culture digitalization home and abroad.

Abstract: As the knowledge of intangible cultural heritage is the experience which is accumulated for a long time, it is difficult to express the complex relationships completely. In order to preserve the content of intangible cultural heritage effectively, the knowledge should be classified by a rational standard. Firstly, this paper discussed the special character and information processing technology of intangible culture heritage; Secondly, the classification of intangible cultural heritage is designed based on its character and the theory of knowledge classification, and then a knowledge modeling framework for intangible cultural heritage is designed based on this classification. Application has proved that it is feasible and effective, and could help the users to master the knowledge and its relationship from various perspectives.

Abstract: In this paper, we connect the pedometer to the mobile phone or personal computer using the platform of IOT. This reduces the defect of pedometer as a single node. The pedometer part integrates ADXL345 acceleration transducer and MSP430 MCU to get the data of steps, energy consumption and speed of a walker with low latency, then uploads this digital information to mobile phone or personal computer using Bluetooth technology. The data information can be uploaded into the pedometer server to realize online query of walkers' exercise records, exercise guidance and other function.

Abstract: The microwave resonant cavity is the sensor of wetness measurement in medium perturbation method. Local eddy current and viscous dissipation of stream will cause the temperature difference of cavity, which led to the shift of resonant frequency affecting the stability of sensor. This paper calculates the temperature distribution of cavity under conditions that varieties of steam parameters and velocity of flow by flow-solid coupling method. The thermal deformation of different conditions of cavity is calculated. The influence of thermal deformation to the resonance frequency of resonant cavity is analyzed, according to the average value of node deformation of the cavity effective surface. The results show that the average temperature of cavity and thermal deformation increase with the steam parameter increase and the offset value of resonance frequency increases. The wetness measurement scheme of wet steam on the turbine exhaust needs to improve to reduce the effect of cavity body deformation.

Abstract: Steam pressure and resonant frequency of microwave cavity are important measure parameters of microwave wetness measurement system. The measuring precision of pressure and frequency directly affect the accuracy of wetness measurement. This paper takes different pressure and wetness of steam as example to analyze the parameter uncertainty of measurement relationship and deduces standard uncertainty of wetness measurement. The system comprehensive uncertainty is identified, when the parameters measurement, cavity heat expansion, sampling error, sedimentary water film and so on are considered. The result shows that the system uncertainty is less than 0.004%. The system uncertainty introduced by pressure measurement is small and can be neglected, but the system uncertainty from frequency measurement has a great effect. The precisely measurement of resonance frequency is key to ensure the accuracy of the system.