Applied Mechanics and Materials Vols. 701-702

Abstract: In this paper, the system scheme and system architecture for transceiver of WIA-PA are presented. The low-IF topology and direct up conversion method are employed, corresponding to receiver part and transmitter part. And in the baseband part, differential and correlation demodulate received signals, as well as time sync, frequency offset calibrate and frame sync operations are designed for solvation the problem of real radio environmental effects. The chip implements using 0.18μm CMOS process has small chip area and low power consumption. The minimum sensitivity of receiver is less than-85dBm for 1% PER (packet error rate), which is better than the required sensitivity for specification.

Abstract: To resolve the complexity and diversity of data exchange, the paper designed an data exchange system based on middleware technology, which realized different parsing and filtering capabilities. The method can meet the need of data exchange on the premise that network security can be guaranteed. The test results show that functionality and performance of the system meet the requirements of data isolation and exchange.

Abstract: The arrival of the era of big data for the entire social development provides a great interests and values, but also led to the serious problem of personal information security. This paper analyzes three forms of the security of personal information is threated under the big data era, these three forms are: illegal data acquisition, data abuse, a violation of personal space. And then discusses the countermeasures of the security of personal information protection under the age of big data.

Abstract: As a promising modulation technology for optical communication, Orthogonal Frequency Division Multiplexing (OFDM) is now increasingly used and a lot of ways of improving the optical efficiency of Intensity Modulated/ Direct Detection (IM/DD) systems have been proposed. And real and non-negative OFDM signals are required in this kind of system. Asymmetrically clipped DC biased Optical OFDM (DCO-OFDM), Asymmetrically Clipped Optical OFDM (ACO-OFDM) and Asymmetrically clipped DC biased Optical OFDM (ADO-OFDM) can satisfy this requirement. In this paper, we analysis the properties and performance orderly of the above three systems and simultaneously compare their performance. The simulation results show that DCO-OFDM is efficient in terms of bandwidth while the ACO-OFDM is efficient in terms of optical power. More importantly, ADO-OFDM is both power-efficient and bandwidth-efficient. At the same time, a developmentally proposal for the future OFDM in IM/DD systems is put forward.

Abstract: This paper proposes an experimental study for localizing radio jammers in a multi floors building. We performed signal strength measurement to find propagation path loss characteristics in the building. Then communication nodes around the existing jammers were classified in order to determine a set of boundary nodes. The propagation path losses between the real jammers and the boundary nodes are evaluated by a vector pointer namely, the evaluation feedback metric, e_z, to find the real jammer location. The proposed algorithm was validated via an indirect measurement called hearing range. The results demonstrate that our approach provides an effective method for jamming localization.

Abstract: MDA(Model Driven Architecture)[1] is model-centric software development methodology. Comparing to traditional code-centric method, MDA is closer to real applications, and it owns a higher level of abstraction. It has become an effective way to produce large scale software in heterogeneous environment, and it is widely used to develop web-based complex information systems [2]. Our paper applies MDA approach to design web system representation layer framework with instances, and extend UML model by MOF(Meta-Object Facility). We’ve also defined transform rules and realized the conversion from UML model to Web model. Our framework helps minimize the application code, reduces the dependence of the Servlet API, provides extensible interface, thus improve the efficiency of system development and maintenance.

Abstract: Reuse of software architecture is a relatively difficult problem in the practice of software engineering realm. For solving the problem, this paper presents an approach which is based on architecture reflection. For the reflection mechanism, the main idea is separating system architecture into two levels – meta-level and base-level. And what’s more, this paper presents a formalization model for the approach by using Pi calculus.

Abstract: More and more enterprises are going to expand the business to the Internet and mobile terminals, at the same time, they are unwilling to give up the traditional applications not written in java, so questions come. The author has a deep research on JNI in java during the process of solving problems. This article simply introduces the JNI technology, and combines with the concrete instance to complete JNI cross-platform calling for VC++ program that reflects the using value of JNI technology.

Abstract: Communication network (CN) is the fundamental supporting network for communications systems, and products massive network resources in its construction and operation. Efficient organization and management of these resources is key issue to improve utilization of network resources and enhance overall performance of the CN. Based on the analysis of applying GIS on CN resources management, this paper studied key technical issues, design and implement the CN resources management system based on GIS, to improve the level of CN resources management and application.

Abstract: In the bit interleaving coded modulation (BICM-ID) solution,includes the demodulator and decoder into the iteration and decoding process, and the decoding is completed between demodulator and decoder. In studies, it have been found that the oscillation is generated on logarithmic likelihood ratio (LLR) because the soft information generated by all previous BP iterations is ignored in this solution, so that the BP soft information output by the final BP iterative decoding is not always reliable. In this paper, the above problem is solved by optimizing the iterative demodulation and decoding solution. Aiming at this problem, this paper firstly puts forward a kind of optimization scheme about iterative demodulation and decoding, then the simulation analysis, the result show that, under the premise of ensuring the system complexity basically unchanged, can improve the demodulation and decoding performance of LDPC coded modulation and demodulation system.