Modeling Massive RFID Data Sets: A Gateway-Based Movement Graph Approach

Massive Radio Frequency Identification (RFID) data sets are expected to become commonplace in supply chain management systems. Warehousing and mining this data is an essential problem with great potential benefits for inventory management, object tracking, and product procurement processes. Since RFID tags can be used to identify each individual item, enormous amounts of location-tracking data are generated. With such data, object movements can be modeled by movement graphs, where nodes correspond to locations and edges record the history of item transitions between locations. In this study, we develop a movement graph model as a compact representation of RFID data sets. Since spatiotemporal as well as item information can be associated with the objects in such a model, the movement graph can be huge, complex, and multidimensional in nature. We show that such a graph can be better organized around gateway nodes, which serve as bridges connecting different regions of the movement graph. A graph-based object movement cube can be constructed by merging and collapsing nodes and edges according to an application-oriented topological structure. Moreover, we propose an efficient cubing algorithm that performs simultaneous aggregation of both spatiotemporal and item dimensions on a partitioned movement graph, guided by such a topological structure.     

Fuzzy identity based signature with applications to biometric authentication

We introduce a new cryptographic primitive which is the signature analog of fuzzy identity based encryption (FIBE). We call it fuzzy identity based signature (FIBS). It possesses similar error-tolerance property as FIBE that allows a user with the private key for identity ω to decrypt a ciphertext encrypted for identity ω′ if and only if ω and ω′ are within a certain distance judged by some metric. We give the definition and security model of FIBS and present the first practical FIBS scheme. We prove that our scheme is existentially unforgeable against adaptively chosen message attack in the standard model. To our best knowledge, this primitive was never considered in the identity based signature before. FIBS is of particular value for biometric authentication, where biometric identifiers such as fingerprints, iris, voice and gait are used in human identification. We demonstrate the applicability of our construction to secure biometric authentication.     

三元体系PEG 4000-Cs2SO4-H2O在25,35和45 ℃时的相平衡研究

采用自制的相平衡研究装置，测定了PEG 4000-Cs2SO4-H2O三元体系在25，35和45℃时的等温平衡溶解度，同时给出了该体系的完整相图，在相图中观察到6个相区。结果表明，该体系双液相区随着温度的升高略有增加，结线的斜率也随温度的升高而增大。用四参数方程y=a bx^0.5 cχ dχ^2对该体系的双液线进行了拟合，拟合结果较好。用Othmer-Tobias方程和Bancroft方程对该体系结线的实验数据进行了关联，所有线性相关系数均大于0．98。热重分析确定平衡固相组成为无水硫酸铯。     

放射性铌铁精矿中铀钍脱除及分离

通过对国内某企业进口放射性铌铁精矿进行工艺矿物学分析,确定该精矿的主要矿相为烧绿石,同时伴生钛铁矿和白云母,矿石中放射性元素U和Th的含量分别为0.27%和1.03%。针对该铌铁精矿,探索H2SO4-Fe(Ⅲ)、H2SO4-HF-H2O2、H2SO4-HF、H2SO4-HF-H2O2-(NH4)2CO3体系中U和Th的浸出及分离效果,最终确定H2SO4-HF-H2O2-(NH4)2CO3多段浸出工艺能有效实现U和Th的脱除与分离。U、Th的脱除率分别为100%和80%。基于研究提出了铌铁精矿U、Th脱除及分离工艺流程。     

循环流化床风室的压力脉动特性分析

针对直径为0.205m,高度为7m的冷态高密度循环流化床(CFB)试验台,在表观气速为6.3m/s的条件下,借助小波理论对不同循环流率、不同出口结构的压力脉动特性进行了分析。结果表明:不管是高密度条件下还是低密度条件下的压力脉动,均属于低频脉动,脉动幅度为0~12.5Hz;在相同的出口结构和同一表观气速下,随着循环流率的增加,风室的压力增加,压力脉动的幅度也增加;在同一表观气速和相同循环流率下,Г型突变出口结构的风室压力和压力脉动幅度的增长速率均比C型光滑出口结构的大。     

Principle and realization method of tunnel deformation detection based on image recognition and data transmission technology

To detect the deformation of the tunnel structure based on image sensor networks is the advanced study and application of spatial sensor technology. For the vertical settlement of metro tunnel caused by internal and external stress after its long period operation, the overall scheme and measuring principle of a tunnel deformation detection system is introduced. The image data acquisition and processing of detection target are achieved by the cooperative work of image sensor, ARM embedded system. RS485 communication achieves the data transmission between ARM memory and Host Computer. The database system in station platform analyses the detection data and obtain the deformation state of tunnel inner wall, which makes it possible to early-warn the tunnel deformation and take preventive measures in time.     

Precise and fast phase wraps reduction in fringe projection profilometry

Phase wraps in a 2D wrapped phase map can be completely eliminated or greatly reduced by frequency shifting. But it usually cannot be optimally reduced using conventional fast Fourier transform (FFT) because the spectrum can be shifted only by a integer number in the frequency domain. In order to achieve a significant phase wrap reduction, we propose a fast and precise two-step method for phase wraps reduction in this paper, which is based on the iterative local discrete Fourier transform (DFT). Firstly, initial estimate of the frequency peak is obtained by FFT. Then sub-pixel spectral peak with high resolution is determined by iteratively upsampling the local DFT around the initial peak location. Finally, frequency shifting algorithm that operates in the spatial domain is used to eliminate phase wraps. Simulations and experiments are conducted to demonstrate the superb computing efficiency and overall performance of the proposed method.     

新型紫外光固化涂料的研制

以四氢邻苯二甲酸二缩水甘油酯与丙烯酸反应制备四氢邻苯二甲酸二缩水甘油丙烯酸酯光敏低聚物,用异佛尔酮二异氰酸酯对其进行改性,将自制改性低聚物与活性稀释剂、光引发剂及其他助剂配制新型紫外光固化涂料。研究了活性稀释剂、光引发剂种类及用量对光固化膜力学性能、附着力、硬度等方面的影响,并利用红外光谱对涂料及固化膜结构进行表征,确定了新型紫外光固化涂料的较佳配方。研究结果表明,该涂料固化速度快,硬度3H,附着力1级,拉伸强度25.3MPa,断裂伸长率9.0%,并且具有较好的耐热性和柔韧性。