A cooperative CDMA-based multi-channel MAC protocol for mobile ad hoc networks

In this paper, we present CCM-MAC, a cooperative CDMA-based multi-channel medium access control (MAC) protocol for mobile ad hoc networks (MANETs) in which each node has one half-duplex transceiver. The protocol mitigates the multi-channel hidden and exposed terminal problems by using information about channel usage gleaned from overhearing (cooperating) neighbours. By accounting for the multiple access interference, CCM-MAC also addresses the near-far problem of CDMA in MANETs enabling concurrent transmissions on each channel. We provide an analysis of the maximum throughput of CCM-MAC and validate it through simulation in Matlab. We also compare the throughput it achieves to IEEE 802.11, a multi-channel MAC protocol, and a CDMA-based MAC protocol.     

一种多通道视频编解码技术的设计与实现

针针对多通道视频编解码技术实现较困难的问题,提出了把Linux多线程思想引入硬件视频编解码模块,以解决多通道视频编解码问题.结合现代软件工程思想,将编解码软件模块分为Linux内核层、中间件和应用层三个层次,降低了多通道视频编解码的设计难度,具有很强的实用性和扩展性.将该方法应用于可视IP电话终端实践,验证了该方法的可...     

几种新型集成硅微(型)传感器系统

介绍了作者近年来在硅微机械加工技术和半导体集成电路技术相结合的基础上研制的硅微机械与光纤组合式阵列声传感器、集成硅微机械光压力传感器和微型多道成像光谱分析系统的结构、工作原理及制造工艺.     

基于嵌入式WEB服务器的多通道温湿度监测仪

以MSP430F149为控制芯片，采用嵌入式WEB服务器技术，设计了多通道远程温度湿度监测仪。该监测仪可同时监测多迭8路温度信号和8路湿度信号，并采用TCP／口通讯协议和远程计算机连接，能在远程计算机上以Web页面的方式动态显示现场温度及湿度信息。该监测仪具有良好的测试精度和友好的监测操作界面，尤其在需要多点组网监测的大型仓库、温室及实验室等有很好的应用前景。     

多通道SPR影像传感器及其对生物分子的检测

采用多通道SPR影像传感系统结构,通过不同通道之间的比较,提取待测分子与探针分子之间相互作用所引起的特异性响应,实现了对生物分子相互作用的实时、高精度、动态检测。该传感系统的光路设计使得入射光可以在可能发生共振的角度范围内以不同角度同时照射各个通道,通过SPR影像可以同时检测不同角度入射光线的反射光强。这样,各通道共振角的分布可以方便地实时监测,同时避免了非特异性响应和机械调节带来的误差和不便。     

An empirical study on consumer online shopping channel choice behavior in omni-channel environment

With the rapid diffusion of smart devices, retailers provide new forms of interactive communication channels, enabling their consumers to access through the mobile channel. The retailers recognize the importance of the mobile channel as an efficient sales channel and as a tool for CRM (Customer Relationship Management). However, CRM has become increasingly complex after adopting it to the mobile channel. It is imperative for retailers to understand consumer behavior in an omni-channel circumstance. Using the four-year transaction data obtained from the online home-shopping provider that expanded its online service (telephone, ARS, Internet website) onto a mobile platform, this research analyzes the consumer channel choice behavior in the perspectives of consumer sociodemographic information, consumer behavior, and corporate communication strategies. To explain channel choices in the omni-channel environment, we use multivariate probit model with sociodemographic variables, communication strategies, order hour, and product categories. Our empirical results indicate that age and gender have significant influences on channel choice behavior. Consumer fixates their inflow channel. Communication strategies such as SMS and app push alarm significantly influence consumer channel choice. Consumers using mobile channel are making purchases without time constraints, while others not. We observed that products that have characteristics of experience goods or credence goods tend to be purchased via mobile and Internet channels that provide detailed and additive information like consumer reviews. Finally, the results revealed substitution effect between most of the channels, except for the Internet and telephone. Our investigation contributes to omni-channel online shopping literature by empirically testing the choice behavior, cross-channel effects, and also by providing insights for online retailers.     

A framework for post-disaster communication using wireless ad hoc networks

Disaster management system requires timely delivery of large volumes of accurate messages so that an appropriate decision can be made to minimize the severity. When a disaster strikes, most of the infrastructure for communication gets uprooted. As a result, communication gets hampered. A well designed Internet of things (IoT) can play a significant role in the post-disaster scenario to minimize the losses, and save the precious lives of animals and human beings. In this paper, we have proposed a framework for post-disaster communication using wireless ad hoc networks. The framework includes: (i) a multi-channel MAC protocol to improve the network throughput, (ii) an energy aware multi-path routing to overcome the higher energy depletion rate at nodes associated with single shortest path routing, and (iii) a distributed topology aware scheme to minimize the transmission power. Above proposals, taken together intend to increase the network throughput, reduce the end-to-end delay, and enhance the network lifetime of an ad hoc network deployed for disaster response. A multi-channel MAC protocol permits the transmission from hidden and exposed nodes without interfering with the on-going transmission. We have compared the proposed framework with an existing scheme called Distressnet [1]. Simulation results show that the proposed framework achieves higher throughput, lower end-to-end delay, and an increased network longevity.     

虚拟世界中立体声合成与播放技术研究

研究虚拟世界中多声道立体声合成与播放的简化算法。文中首先分析多声道立体声的合成原理，以及混声效果的评价标准及评价声源对整个声音所作贡献的公式，然后给出多声道立体声实时合成和播放的简化算法，整个算法简单容易实现。     

消防机器人底盘热防护多通道温度采集系统设计与试验

针对消防机器人底盘工作环境不低于300℃的要求,以及对底盘型腔进行多点测温的需求,开发了基于Labview的消防机器人底盘热防护8通道温度采集软硬件系统。实现了基于串口Modbus RTU协议的温度数据采集与传输,系统具有用户注册、串口配置、温度曲线实时显示、超温声光报警、数据显示与保存、历史数据回放、数据表显示与小波降噪等功能。通过该系统对底盘型腔进行了4种工况的热防护温度检测试验,验证了系统的可靠性。此外,针对温度曲线中出现的噪声干扰,引入了小波分析,采用Labview与Matlab混合编程方法,通过小波阈值滤波算法对采集到的数据进行了降噪处理,并与各通道温度原始数据进行了对比,达到了较好的滤波效果。该系统可视化效果好,数据采集实时且准确,对工业现场多点温度的实时检测具有借鉴意义。     

A fuzzy logic approach to detect hotspots with NOAA/AVHRR image using multi-channel information fusion technique

This paper proposes a novel approach to detect hotspots using NOAA advanced very high resolution radiometer (AVHRR) for the Jharia, Jharkhand (India) region. Jharia coalfield in Jharkhand is the richest coal bearing area in India that contains a large number of mine fires which have been burning for several decades. In this paper, a fuzzy based methodology has been applied for the determination of hotspots to Jharia AVHRR images based on a theoretical model that establishes relationship among AVHRR channel 4, channel 5 and different vegetation indices. The algorithm consists of four stages: data preprocessing, multi-channel information fusion, hotspot detection using fuzzy logic approach and validation of result. The most commonly used existing algorithms like contextual algorithms, multi-thresholding, entropy based thresholding, and genetic algorithms have limitation that they need some mathematical model for training in order to get the required result. The employed fuzzy logic approach overcomes this requirement and in addition, it is flexible, tolerant of imprecise data and is based on natural language. The results were compared with the results obtained by ground survey and a good agreement has been obtained between observed and predicted hotspots.