Volume 1 Issue 3
Authors: Hafizal Mohamad; Rashid A. Saeed; Mazlan Abbas; Borhanuddin Mohd. Ali
Abstract: The next generation of the wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. Handover delay is one of the problematic issues that users are faced in the heterogeneous networks. However, in the case of both the WiMAX and the WiFi technologies which are located at the same base station (BS), the vertical handover (VHO) delay will be less as compared with the two conventional WiMAX/WiFi heterogeneous networks with two different wireless Internet service providers (WISP). Nevertheless, protocol conversion is still adding delay and jitter for data exchange between the needed two technologies. In this paper, In order to reduce the delay in the protocol conversion, a new industrial design for WiWi (WiMAX and WiFi) adaptation layer is proposed. The realization of the interworking between these two standards is discussed and evaluated. The results show that the proposed scheme -with the scenario under study- has better performance than other related works.
Keywords: WiFi; WiMAX; Convergence; Heterogeneous Network; Seamless Handover
Authors: Bachir Boucheham
Abstract: Electrocardiogram (ECG) morphology deviation from normal beat is a sign of abnormal behavior and a significant information for cardiologist to depict cardiac diseases. Most existing methods for such a task use single beat classification with various tools. However, these approaches usually ignore the repetitive nature of the ECG. In this study, we adapt and apply a previously developed method for quasi-periodic time series comparison (SEA) to detect the morphology change in the ECG. The basic idea is to perform segment-wise comparisons of the ECG where one segment stands for the reference (normal) behavior and the other segment for the unknown behavior segment. Due to many difficulties, this is a very complex problem to solve, especially with regard to the phase shift and the number of periods in each segment problems. The new approach is applied on records from the Massachusetts Institute of Technology – Beth Israel Hospital (MIT-BIH) arrhythmia database. Results show the effectiveness of the proposed method in detecting the significant morphology changes of the ECG. The author believes that the method could also be useful for clustering and summarizing of ECG, among other applications.
Keywords: Electrocardiograms (ECG); Anomaly detection; Pattern recognition; Time series comparison; Shape Exchange Algorithm (SEA)
Authors: Rached Tourki; Fatma Sayadi; Mohamed Atri
Abstract: This paper presents different implementations of the LPC (Linear Predictive Coding) algorithm used in the majority of voice decoding standard. The windowing/autocorrelation bloc is implemented by three different versions on an FPGA Spartan3 with Microblaze soft core processor using Embedded Development Kit (EDK). Allowing the possibility to integrate the soft core processor a first solution consists of a pure software implementation of the LPC using this core RISC processor. Second solution is pure hardware architecture implemented using VHDL based methodology starting from description until integration. Finally, hardware/ software co-design is given. The hardware part consists of the autocorrelation core that solves the part of the algorithm with higher computational costs. The software part consists of the embedded soft core processor that manages the windowing bloc. The implementation results are presented, a comparison is then made between the three alternative architectures with different data lengths for performance and area.
Keywords: Linear Predictive Coding; System on Programmable Chip; FPGA; Co-design
Authors: Xu Zou; Zunqi Yang
Abstract: In recent years, the problems of college graduates employment difficulties are increasingly concerned by all sectors of society. Applied quantitative analysis method from the current employment situation of university students, this thesis summarizes the current difficult employment problem of university students. On this basis, quantitative analysis of the impact is made, and finally countermeasures are proposed to expect to be able to solve the contemporary employment problem of university students and provide operational recommendations.
Keywords: Reasons; the Graduate Employment; Measures
Authors: Wenjie Niu
Abstract: Elastic theory is employed for short span suspension bridges while deflection theory and finite element theory are used for long span suspension bridges. But the tension deformations of the suspenders are usually ignored in the elastic theory when to compute the internal force of small span suspension bridge. In this paper, a flexibility method considering suspenders deformation was proposed to calculate the internal load of a wire suspension bridge. Its span is less than 200 meters and can be analyzed with elastic theory. Results indicate that the horizontal cable tension force of wire suspension bridge by flexibility method ignoring the suspenders deformations is 0.01671% bigger than the real redundant bar force by flexibility method considering the suspenders deformations. A new equation considering suspenders deformation based on the old common equation was established to find the more accurate horizontal tension force at cable midpoint.
Keywords: Flexibility method; Wire suspension bridge; Tension deformations of the suspenders; Elastic theory
Authors: Parviz keshavarzi; Abdalhossein Rezai
Abstract: This paper presents a new efficient implementation approach of elliptic curve cryptosystem based on a novel finite field multiplication and a high performance scalar multiplication algorithm for wireless network authentication. In this new finite field multiplication, CLNZ sliding window method is used on the signed-digit multiplier in order to reduce the multiplication steps. In addition, in scalar multiplication algorithm of the proposed implementation approach, point addition and point doubling operation.So the multiplication cost in the proposed implementation approach reduced considerrably.Using this new implementation approach,the security of the number of multiplication steps at about 40%-82.4% for d=2-10 in compare with montgomery modular multiplication algorrithm.In addition,the ellptic curve cryptosystem enhances about 88%-97%in the compare with the implementation approach of traditionnal windows NAF elliptic curve scalar multiplication algorithm(based on interleaving)where w=4 and 8,andd=8.
Keywords: wireless network security; authentication; elliptic curve cryptosystem; scalar multiplication; finite field multiplication; signd-digit recoding
Authors: Guang Dong; Ming Fang; Wei He; Yuhang Wang
Abstract: This paper introduces the software architecture of home gateway system based on embedded Linux technology, using Socket programming technology and implementing exchange between the RS232 data within the system and external Internet data. This system completes the database design on embedded home gateway using SQLite architecture, and implements the application of the SQLite embedded database on home gateway. Analysis of TCP/ IP protocol, according to the embedded home gateway protocol, by cutting the TCP/ IP protocol layer, the system implements the transplant of TCP/ IP protocol stack on embedded home gateway. Web server is successfully ported, and embedded Linux operation system is ported to home gateway platform.
Keywords: Embedded Linux; Home Gateway; SQLite; Protocol Stack; Web Server
Authors: Jingmin Chen; Yating Liang
Abstract: The flourishing development of computer technology and internet popularity have resulted in booming trends of network politics and a dramatically more complex network politics group structure. Aim to find several key types among the political blog groups, such as the core group members, the relatively important members and members with special characteristics, the article uses social network analysis method (centrality analysis) to analyze the political blog community consist of the top50 Politics blogs in People (People's Daily website) with UCINET. The found of those members has an important significance for the further understanding of the political blog community.
Keywords: political blog; social network analysis; UCINET