A truck scheduling problem arising in intermodal container transportation

We address a truck scheduling problem that arises in intermodal container transportation, where containers need to be transported between customers (shippers or receivers) and container terminals (rail or maritime) and vice versa. The transportation requests are handled by a trucking company which operates several depots and a fleet of homogeneous trucks that must be routed and scheduled to minimize the total truck operating time under hard time window constraints imposed by the customers and terminals. Empty containers are considered as transportation resources and are provided by the trucking company for freight transportation. The truck scheduling problem at hand is formulated as Full-Truckload Pickup and Delivery Problem with Time Windows (FTPDPTW) and is solved by a 2-stage heuristic solution approach. This solution method was specially designed for the truck scheduling problem but can be applied to other problems as well. We assess the quality of our solution approach on several computational experiments.     

基于多核手机芯片的TD-SCDMA非信令模式下行同步方案

随着TD-SCDMA无线通信系统商用的成熟,研究多核手机芯片的非信令模式符合终端测试发展需求。通过对TD-SCDMA下行同步过程的研究,设计了快速的非信令模式下行同步实现方案,同时结合多核手机芯片的特点充分优化下行同步过程的实现。实现结果表明,该下行同步方案处理时延40 μs左右,频偏估计结果的均值和标准差分别稳定在10 Hz、32 Hz左右,能够用于简化多核终端生产测试过程,具有一定的工程应用价值。     

基于可信根的移动设备安全研究

随着移动通信技术的不断成熟,移动用户数量飞速增长,人们希望在工作场合使用自带设备（Bring your own device,BYOD）的意愿不断增强。移动设备的运用在给用户带来随时随地接入系统、方便快捷获取数据和交流业务的同时,也给用户带来了移动设备固有的相关安全风险。目前的移动设备由于缺乏基于硬件的可信根功能,不能为用户提供强有力的安全保证。文章详细介绍移动设备安全组件,给出移动设备体系架构,着重描述使移动设备能够更安全使用所需的基本安全功能。     

条形码在图书馆移动服务中的应用研究

对一维码与二维码的特征与常见类型进行了比较分析.随着智能手机持有率的上升与无线网络覆盖区域的扩大,在这种移动环境下条形码技术的应用成为离线状态物体与在线数据库相连接的桥梁.通过介绍国内图书馆汇文系统对二维码的应用事例,以及国外图书馆二维码技术的使用事例,提出在图书馆领域使用条形码技术推进移动服务的建议.     

基于WiFi技术在井下无线通讯的应用

WiFi技术和VOIP技术相结合应用到煤矿井下是一种新的解决矿井无线通讯方案,其主要是发展一种低成本的无线网络,在煤矿有较好的发展前景。本文根据煤矿对井下无线调度系统的需求,提出将WiFi无线技术与VOIP技术相结合实现井下无线调度通信系统的方案。     

Mobile phone ownership and usage among pre-adolescents

Research has revealed that the mobile phone is, for adolescents, a medium which permits communication without the surveillance of parents, families and teachers. Indeed, the current study found this to be the case with younger pupils, too. However, communicating with family members appeared just as important, if not more, for these primary aged children. This study focused on the ownership and usage of mobile phones in a sample (N=351) of 10- to 11-year-old children in Gloucestershire primary schools (N=7). Some 45% of the sample possessed mobile phones. Nearly half of their calls (47%) were used for chatting with family or friends; 26% were to let their parents know their whereabouts; and others (20%) were “convenience” calls, i.e. to ask to be picked up etc. Other uses of the mobile in addition to chatting and making arrangements, although not always positive, were also made apparent. Thus, some two fifths of the children reported that they had made an “emergency” call (examples were given), about 17% had received “frightening” calls. A sizeable minority (20%) reported that their mobile had been damaged or stolen. This research also considers the amount of money that the pupils claimed to spend on their mobile calls every month as well as their means of purchasing the mobile and its up-keep.     

Mobile Web Middleware of NFC Context-Awareness Applications

With the development of wireless networks and mobile computing, more advanced applications with context-awareness and adaptability to their changing context are needed. However, building context-aware applications is difficult due to the lack of adequate infrastructure support. In this paper, a web middleware architecture for the development of context-awareness applications using near field communication （NFC） is proposed. Based on it, the efficient support for acquiring, interpreting, and accessing context is provided, and the user＇s quality of experience is improved. Moreover, a mobile web middleware for the testing and full realization of NFC context-awareness applications has been developed together with two application examples.     

求解带时间窗车辆路径问题的混合Memetic算法

为提高带时间窗车辆路径问题的求解精度和求解效率,设计了一种混合Memetic算法。采用基于时间窗升序排列的混合插入法构造初始种群,提高解质量的同时兼顾多样性,扩大搜索空间;任意选择组成父代种群,以维持搜索空间;运用简化的变邻域搜索进行局部开发,引入邻域半径减少策略提高开发效率,约束放松机制开放局部空间;以弧为对象,增加种群向当前最优解和全局最优解的后学习过程。实验结果表明,所提出的算法具有较好的寻优精度和稳定性,能搜索到更好的路径长度结果,更新了现有研究在最短路径长度的目标函数上的下限。     

基于手机录像功能的相变类观察实验改进

建立了一种基于手机录像的简便观察方法，可以用于毛细管法测定熔点、毛细管法测定沸点、氯化铵的结晶等相变类实验的改进。该方法一方面可以明显提高相变类实验的观察效果，便于学生清晰准确地捕捉记录相变过程；另一方面可以反复回放实验过程，便于学生撰写实验报告和教师的检查指导。该方法对提高学生的实验积极性和实验效果具有较大的帮助，并为实验的设计提供了更多的可能性。     

Superparamagnetic Nanoparticles with Efficient Near-Infrared Photothermal Effect at the Second Biological Window

Superparamagnetic nanoparticles (iron oxide nanoparticles—IONs) are suitable for hyperthermia after irradiating with radiofrequency radiation. Concerning the suitability for laser ablation, IONs present a low molar absorption coefficient in the near-infrared region close to 800 nm. For this reason, they are combined with other photothermal agents into a hybrid composite. Here, we show that IONs absorb and convert into heat the infrared radiation characteristic of the so-called second-biological window (1000–1350 nm) and, in consequence, they can be used for thermal ablation in such wavelengths. To the known excellent water solubility, colloidal stability and biocompatibility exhibited by IONs, an outstanding photothermal performance must be added. For instance, a temperature increase of 36 °C was obtained after irradiating at 8.7 W cm⁻² for 10 min a suspension of IONs at iron concentration of 255 mg L⁻¹. The photothermal conversion efficiency was ~72%. Furthermore, IONs showed high thermogenic stability during the whole process of heating/cooling. To sum up, while the use of IONs in the first bio-window (700–950 nm) presents some concerns, they appear to be good photothermal agents in the second biological window.