Earticle

A statistical analysis has been made on 969 two-syllabic words in Uyghur Acoustical Database. The major part of this paper concentrates on the basic acoustic features of two-syllabic harmonious words including formant frequency, resonance peak value, vowel duration, vowel pitch and the sound intensity. And we have summarized certain rules and conclusions of great importance for adjusting vowel harmony in parametric speech synthesis or waveform concatenated speech synthesis system.

This paper derives the analytical expression of the temporal autocorrelation function (ACF) of the non-stationary three dimensional (3D) multipath scattering channels, in which scatterers move with constant velocities in random directions around transceivers. The analytical expression involves high dimensional integration within finite interval, thus a methodology based on ray-tracing is proposed to carry out its numerical solution. The analytical expression and the corresponding ray-tracing based model serve as the canonical forms for the correlation analysis of non-stationary 3D multipath scattering channels, which include two special cases: two dimensional (2D) multipath scattering and stationary multipath scattering. Numerical results show that: in case of non-stationary 3D multipath scattering, with the increase of the velocity and the density of scatterers, the temporal ACF would attenuate more rapidly. These results would allow engineers more appropriate determination on coherence time and coherence bandwidth for vehicle-to-vehicle communication systems.

In this paper, we propose a local adaptive transmission power control method to improve the network connectivity and energy efficiency etc. for wireless sensor networks. Path loss exponent and energy control coefficient are studied carefully to show the minimum cover district of each node more accurately based on network environment and the application scenarios. Our proposed local adaptive power control method can also provide self-healing function which makes the network maintain the best performance for a long time when a few nodes exhaust their energy or a fresh batch of nodes are deployed. Simulation results show that our proposed method is very effective in establishing a good logical network structure and prolonging the network lifetime.

Self-localization is a fundamental problem in mobile robotics. It consists of estimating the position of a robot given a map of the environment and information obtained by sensors. Among the algorithms used to address this issue, the Monte Carlo technique has obtained a considerable attention by the scientific community due to its simplicity and efficiency. Monte Carlo localization is a sample-based technique that estimates robot´s pose using a probability density function represented by samples (particles). The complexity of this algorithm scales proportionally to the number of particles used. The larger the environment, the more particles are required for robot localization. This fact limits the use of this algorithm in large size environments. In order to improve the efficiency of the Monte Carlo technique and allow it to be used in large environments we propose a parallel implementation of it. Our implementation is based on OpenMP and MPI message passing interface. Experimental results are used to show the efficiency of our approach.

A trust and reputation management framework for VANETs (Vehicular Ad Hoc Networks) is proposed. In the framework, a similarity mining technique is used for identifying similar messages or similar vehicles. And a reputation evaluation algorithm is proposed for evaluating a new vehicle’s reputation based on the similarity theory. Similarities from different recommenders are used as weights for computing a vehicle’s recommendation based reputation. An updating algorithm for reputations is proposed in the framework. The framework is applied to decide whether a message is trustworthy when a vehicle receives an event message.

Nowadays, Dense Wavelength Division Multiplexing (DWDM) has become a key component of the world’s communications infrastructure. The significant improvement in high-speed electronics and optical components, and multi-level modulation formants and coherent receiver technology has enabled high rate data transmission. DWDM promises to increase the bandwidth per fiber as the bit rate and the number of wavelengths increase. According to ITU-T G.694.1, mostly used DWDM systems have been operating with 40, 80 and 120 wavelengths, and with advanced modulation schemes and coherent receiver technology along better dispersion management, a single wavelength in today’s world can able to transmit upto 100Gbps; thus total maximum bandwidth is an amazing 4Tbps, 8Tbps, and 12Tbps, respectively. However, today’s commercial systems have a fiber transmission requirement for around 10Tbps, and globally demand has been increasing about 35% to 45% per year. Hence, to meet this increasing demand transponders transmission rate must have to be increased. This paper reviews the progress and techniques used to increase wavelength throughput from 2.5Gbps to 100Gbps, and investigates the challenges to transmit data beyond 100Gbps in a single operational cycle.

The frequency hopping technology is widely used in wireless sensor networks with the security becomes more and more important. Channel evaluation is important for adaptive frequency hopping system and we proposed a scheme of optimal channel selection with channel evaluation, which can get an accurate and comprehensive channel evaluation by analyzing the Signal-To-Noise Ratio (SNR), loss rate and delay.

An ideal routing strategy shall be able to help the delay tolerant network (DTN) achieve an optimal transmission performance under the premise of lower energy consumption. However, due to the diverse of the application scenarios, it is hard to use one or more types of routing strategies as a universal optimum solution. There is a need to establish a routing strategy model of the corresponding DTN network for different application scenarios, analyze and evaluate the strategy model in combination of the knowledge of the operational research and statistics. For a complex data transmission DTN network scenario, with the introducing of a line programming method, the big-data and multi-node network transmission problem can be abstracted to a large-scale line programming problem. In this paper, the feasibility of solving the large-scale line programming problem by the column generation algorithm has been analyzed, and a column generation algorithm-based DTN routing strategy under the complex data transmission scenario has been designed. This routing strategy can realize the quantization of the routing strategy performance by the column generation algorithm. Also, by the simulation experiments, the performance of complex data transmission DTN routing strategy under different factors has been analyzed, and the performance of the column generation algorithm-based DTN routing strategy has been compared with the performance of the traditional jet waiting routing strategy

CAN bus is ISO international standard serial communication protocol. It is one of the most widely used fieldbus in the world. It has become the standard bus of embedded industrial control LAN. Ethernet is the most common communication protocol standard that is applied in the existing LAN. Networked industrial control usually adopts fieldbus and Ethernet network, thus the protocol conversion problems of the heterogeneous network composed of Ethernet and CAN bus has become one of the research hotspots in the technology of the industrial control network. STM32F103RC ARM microprocessor was used in the design of the Ethernet-CAN protocol conversion module, the simplified TCP/IP communication protocol - uIP protocol was adopted to improve the efficiency of the protocol conversion and guarantee the stability of the system communication. The results of the experiments show that the designed module can realize high-speed and transparent protocol conversion.