国产聚苯乙烯在窗口膜生产中的应用与实施

简要介绍BOPS国产化原料在环保绿色窗口膜生产中的应用与实施，阐述聚苯乙烯（BOPS）料粒在薄膜生产中使用的特点，以及其良好的发展前景，重点论述该产品生产过程中的关键技术。     

基于蜂窝网络拓扑的无线传感网定位算法

针对无线传感网中DV-Hop定位算法过于依赖信标节点数量以及定位精度低的问题,提出基于蜂窝网络拓扑的定位算法(LABCNT)。通过对网络中节点的有向筛选,选取满足特定条件的节点,构造一个蜂窝的网络拓扑结构,得到网络上节点的相对位置;根据拓扑结构中的第二个信标节点确定网络上节点的绝对位置;将已定位的节点升级为协作节点,采用最小二乘算法对域内其它未知节点进行定位。仿真结果表明,与DH-RLS、IDVH-LA、IDVH-HCHEC算法相比,LABCNT算法的定位精度较高,所需信标节点数量最少。     

Development of Acoustic Leak Detection and Localization Methods for Inlet Piping of Fugen Nuclear Power Plant

The development work carried out on Fugen NPP is focused on detection of a small leakage on the reactor's inlet feeder pipes at an early stage by an acoustic leak detection method with usage of high-temperature resistant microphones. Specifically, the leak rate of 0.046 m³/h has been chosen as a target detection capability for this system. A cross-correlation technique has been studied for leak detection under low signal-noise ratios. The study shows that the sound diffusion on piping causes distortion of leak signals that results in their low correlation. A leak-location estimator and multi-channel correlation value, associated with estimated leak position, have been employed to detect such low-correlated leak signals. A method based on cross-correlation of signal spectral components has been proposed to deal with non-stationary leak signals. Joint-Time-Frequency-Analysis has been applied to analyze such signals, whilst a Wavelet decomposition technique has been used to extract their short-term spectral fluctuations. Since the spectral components are less affected by signal distortion, they provide higher correlation value and can be applied for leak detection under lower signal-noise ratios. The possibility of detecting and locating a small leakage by the methods proposed has been demonstrated by a number of simulation tests conducted on the Fugen NPP site.     

基于GIS和SLAM的机器人大范围环境自主导航

机器人自主导航技术的基础是其自定位能力,同时同步定位与建图(SLAM)是实现机器人自定位的重要方法。目前由于大规模SLAM技术发展的限制,机器人很难实现在大范围环境下进行建图和导航,并且尚没有结合SLAM和实际地理空间信息指导大范围机器人导航的完整自主导航系统。提出基于GIS和SLAM的机器人大范围环境自主导航方法,利用真实的城市空间路网信息,以地理信息系统(GIS)空间数据库的存储和计算能力为数据支撑,基于提出的大范围导航算法,实现了一套包含空间数据库、SLAM、导航算法的完整系统,具有良好的可复用性和可扩展性,符合实际生活场景,可以指导机器人进行大范围条件下的导航和建图行为。同时通过对机器人激光建图信息的存储,使得再次经过本区域的机器人可以在户外精确定位,实现在室外GPS缺失或误差条件下自身位置的修正。此外地图信息的存储可以实现多机器人对地图信息的复用,为多机器人的规划提供支撑。同时将人类世界的空间信息与机器人建图信息相结合,细化和丰富了原有的空间信息。     

昆山思常路茶室

昆山市思常路茶室的设计探讨了在现代中国城市中如何让居民重新接触自然。同时,它还在建筑实体上用低技术、低成本的手段实验了平缓曲线的形式语言。此设计也可以看做海外建筑设计在中国产生的另类影响。     

Overshoot‐free nonholonomic source seeking in 3‐D

This paper studies the problem of steering a nonholonomic vehicle with a constant forward velocity to localize a source in 3‐D. Of two existing 3‐D source‐seeking strategies, one causes overshoots of the vehicle around the source while the other shows slow convergence rate in approaching the source. We propose a composite of these 2 control strategies to achieve a balanced performance by taking advantage of both strategies. Moreover, we prove local exponential stability for a static spherical signal map using averaging and describe the influence of the parameters using root locus method. Simulation results further validate the effectiveness and advantages of the combined strategy.     

Energy-efficient WiFi scanning for localization

WiFi radio signals are commonly used for the localization of mobile devices. However, frequent scanning of WiFi reduces user experiences because it consumes significant energy on mobile devices. In this paper, we propose an energy-efficient WiFi scan system for localization. The proposed system preserves the quality of service of each application and minimizes the energy consumption of WiFi scanning. The main idea is that the system adaptively controls the dwell time of beacon-listening in given locations. We predict the number of scanned access points (APs) according to locations and optimize the dwell time of beacon-listening to obtain the minimum number of scanned APs. The evaluation shows that the proposed system saves the energy consumption of WiFi scans by 33.6% and 45.7%, according to the number of scanned APs, while not decreasing the accuracy of localization in indoor and outdoor scenarios.     

Enhanced radio tomographic imaging with heterogeneous Bayesian compressive sensing

This work explores the novel use of Bayesian compressive sensing (BCS) in radio tomographic imaging (RTI), which aims at addressing the performance degradation of shadow fade imaging due to multipath interferences, through the sophisticated efforts on enhancing BCS with the capability of heterogeneous-noise-variance learning. Our contribution is twofold. Firstly, we incorporate a hierarchical model of heterogeneous noise variances into sparse Bayesian learning, which can contribute to the enhancement of BCS in terms of noise-variance awareness. Then, under our enhanced BCS (namely heterogeneous BCS) framework, we develop two learning algorithms for the RTI reconstruction. Theoretical analysis will show the potential advantages of using our heterogeneous BCS in mitigating the effect of multipath interferences, as well as in improving the RTI performance with our learning algorithms. Finally, the experimental results in the context of device-free localization and tracking are reported to demonstrate the effectiveness of the proposed approach.     

Distributed algorithm for target localization in wireless sensor networks using RSS and AoA measurements

This paper addresses target localization problem in a cooperative 3-D wireless sensor network (WSN). We employ a hybrid system that fuses distance and angle measurements, extracted from the received signal strength (RSS) and angle-of-arrival (AoA) information, respectively. Based on range measurement model and simple geometry, we derive a novel non-convex estimator based on the least squares (LS) criterion. The derived non-convex estimator tightly approximates the maximum likelihood (ML) one for small noise levels. We show that the developed non-convex estimator is suitable for distributed implementation, and that it can be transformed into a convex one by applying a second-order cone programming (SOCP) relaxation technique. We also show that the developed non-convex estimator can be transformed into a generalized trust region sub-problem (GTRS) framework, by following the squared range (SR) approach. The proposed SOCP algorithm for known transmit powers is then generalized to the case where the transmit powers are different and not known. Furthermore, we provide a detailed analysis of the computational complexity of the proposed algorithms. Our simulation results show that the new estimators have excellent performance in terms of the estimation accuracy and convergence, and they confirm the effectiveness of combining two radio measurements.     

海外工程项目人力资源属地化研究——以中交四航局肯尼亚蒙内铁路项目为例

探讨海外工程项目人力资源属地化的必然性,分析其存在的问题。结合海外项目实际,提出制定人力资源属地化实施方案、建立规范的人力资源属地化管理制度、加强跨文化管理、加强外籍雇员培训、重视对海外项目部中方人员的"赋能"及建立完善的考核激励机制等人力资源属地化提升措施。