基于RFID的磁盘加密系统

文章在跟踪和分析最新磁盘加密技术研究成果的基础上,设计了一种基于RFID的磁盘分区加密系统。该系统由磁盘分区加密软件Partition Crypt与RFID射频卡、USB射频读写端等硬件模块共同组成。软件部分对计算机硬件系统要求低、安装方便、使用简单、加密效果好;硬件部分由单片机与射频模块完成。其中,USB接口采用虚拟USB接口的方法,降低硬件复杂性与成本,具有很高的性价比。经过测试,整个系统功能稳定、性价比高、保密性好,可为广泛使用的基于Windows操作系统的涉密计算机提供加密技术保障,应用前景广阔。     

New instant confirmation mechanism based on interactive incontestable signature in consortium blockchain

The blockchain is a radical innovation that has a considerable effect on payments, stock exchanges, cybersecurity, and computational law. However, its limitations in terms of the uncertainty involved in transaction confirmation are significant. In this paper, we describe the design of a decentralized voting protocol for the election of a block generator in a consortium blockchain and propose a new system framework that allows fast and exact confirmation of all transactions. In addition, to replace a transaction’s owner signature, a new interactive incontestable signature between the dealer and owner is used to confirm a transaction. By means of this signature, the dealer can assure the owner that a transaction will be permanently included in the blockchain in a non-repudiation manner. Moreover, the signatures of all transactions in a block share only one witness that provides membership proof between the block and these transactions. Finally, a security and performance analysis shows that the proposed schemes are provably secure and highly efficient.     

充电桩计量过程中输出与充电需求不匹配问题分析及处理

针对充电桩现场测试设备的充电需求与实际输出不一致,出现电压、电流不匹配的问题,设计了一套检测方案,构建出包括电流检测模块、电压检测模块和示波器检测模块的检测电路,通过采样电压和电流信号,计算出不同负载下充电桩输出电流和电压值,并设计了包括直流电能采集电路,由双通道AD转换AD7380、可编程增益放大器、可编程增益放大器、增益电阻Rg2和电源变换器、低通滤波器电容CL、低通滤波器电阻RL组成的检测电路,在检测电路中,为了提高检测效率,还设置了校正电路。通过试验,本研究方法分析直观,误差低。     

Concept and design of Ad Hoc and Mobile classrooms

Abstract This investigation describes the concept of mobile learning and the design of Ad Hoc and Mobile classrooms. Four classes of mobile learning and implementation of Ad Hoc and eSchoolbag systems are presented. The paper discusses the development of advanced wireless technologies for building an ad hoc classroom to create a modern and new learning environment. As in a traditional classroom, information technology is developed to provide the teacher with aids, such as a blackboard, a board rubber, coloured chalk, a microphone, a voice recorder, a video recorder, and so on, to support teaching and discussions. Additionally, students are provided with an electronic schoolbag which contains electronic books, a notebook, a parents' contact book, a pencil case, writing materials, sheets, a calculator, an address book, and other items. Taking lessons in a lively, vivid and new learning environment, it is expected that students will improve their learning performance with perhaps less attendance in a physical classroom and they gain the flexibility of being able to learn at their own convenience.     

杆在固有振动中的对偶关系

本文研究线弹性均质材料杆的固有振动对偶问题,即两种杆在怎样的截面变化和齐次边界下具有相同固有频率.首先,通过纵向位移和内力的对偶描述,给出两种杆异截面对偶的截面变化条件和边界条件,并将其分类为固定-固定杆与自由-自由杆对偶,固定-自由杆与自由-固定杆对偶等.上述对偶杆具有相同固有频率,而两者的位移振型互为位置坐标的导数.其次,限定两种对偶杆的截面变化相同,给出杆的截面积函数表达式.此时,固定-固定杆与自由-自由杆构成同截面对偶,而固定-自由杆和自由-固定杆的同截面对偶彼此为镜像;等截面杆也具有上述对偶性质.最后,将上述研究推广到材料性质沿轴向变化的变截面杆固有振动对偶问题.文中所有结论均适用于圆轴在齐次边界条件下的扭转固有振动对偶问题.     

拟左群的一个代数结构

给出一个拟左群同构于拟群和左零带的直积的一个充分必要条件,同时给出了左群的收缩诣零扩张的一个刻画。     

关于一种网格运行时结构的若干注记

进程是传统计算机系统的一个核心概念，自1960年出现以来一直沿用至今，进程的一个主要目的是为主体提供一种运行时结构，在操作系统和处理器硬件支持下，代表主体访问和使用各种资源，与传统的单机和并行机计算平台相比，网格计算机中进程所对应的概念面临新的挑战，包括网格资源繁杂、自主控制的条件下的单一系统映像和资源的共享与协同、与特定操作系统的松耦合、时间和空间的流动性、更高级的交互性，提出一种称为网程(grip)的运行时结构，试图解决上述问题，网程运行在网格操作系统之上，代表网格主体，访问和使用网格资源。     

Virtual Triangulation Sensor Development, Behavior Simulation and CAR Integration Applied to Robotic Arc-Welding

Background: An increasing number of industrial robots are being programmed using CAR (Computer Aided Robotics). Sensor guidance offers a means of coping with frequent product changes in manufacturing systems. However, sensors increase the uncertainty and to preserve system robustness, a tool is needed that makes it possible to understand a sensor guided robot system before and during its actual operation in real life.Scope: A virtual sensor is developed and integrated in a CAR hosted environment. The real sensor is of a type commonly used in the arc-welding industry and uses a triangulation method for depth measurements. The sensor is validated both statically and dynamically by matching it with a real sensor through measurements in setups and by comparing a welding application performed in a real and a virtual work-cell created with a CAR application. The experimental results successfully validates its performance. In this context, a virtual sensor is a software model of a physical sensor with similar characteristics, using geometrical and/or process specific data from a computerized model of a real work-cell.     

An Interactive Designing System with Virtual Sculpting and Virtual Woodcut Printing

In this paper, we propose an interactive designing method and a system based on it to create 3D objects and 2D images. This system consists of two subsystems for virtual sculpting to create a 3D shape and virtual printing to produce a picture with a printing block. In the virtual sculpting subsystem, a user can form solid objects with curved surfaces as if sculpting them. The user operates virtual chisels, and can remove or attach arbitrary shapes of ellipsoids or cubes from or to the workpiece. A 3D object generated by virtual sculpting looks like a real wooden sculpture. If using a board as a workpiece, a user can generate a virtual printing block. In the virtual printing subsystem, a user can synthesize a woodcut printing image from the virtual printing block mentioned above, a virtual paper sheet, and a printing brush. The user can synthesize a realistic woodcut print with a procedure similar to the actual woodcut printing.     

On the equivalence between small-step and big-step abstract machines: a simple application of lightweight fusion

We show how Ohori and Sasano's recent lightweight fusion by fixed-point promotion provides a simple way to prove the equivalence of the two standard styles of specification of abstract machines: (1) in small-step form, as a state-transition function together with a ‘driver loop’, i.e., a function implementing the iteration of this transition function; and (2) in big-step form, as a tail-recursive function that directly maps a given configuration to a final state, if any. The equivalence hinges on our observation that for abstract machines, fusing a small-step specification yields a big-step specification. We illustrate this observation here with a recognizer for Dyck words, the CEK machine, and Krivine's machine with call/cc.The need for such a simple proof is motivated by our current work on small-step abstract machines as obtained by refocusing a function implementing a reduction semantics (a syntactic correspondence), and big-step abstract machines as obtained by CPS-transforming and then defunctionalizing a function implementing a big-step semantics (a functional correspondence).     

Optimized data rate allocation for dynamic sensor fusion over resource constrained communication networks

This article presents a new method to solve a dynamic sensor fusion problem. We consider a large number of remote sensors which measure a common Gauss–Markov process. Each sensor encodes and transmits its measurement to a data fusion center through a resource restricted communication network. The communication cost incurred by a given sensor is quantified as the expected bitrate from the sensor to the fusion center. We propose an approach that attempts to minimize a weighted sum of these communication costs subject to a constraint on the state estimation error at the fusion center. We formulate the problem as a difference-of-convex program and apply the convex-concave procedure (CCP) to obtain a heuristic solution. We consider a 1D heat transfer model and a model for 2D target tracking by a drone swarm for numerical studies. Through these simulations, we observe that our proposed approach has a tendency to assign zero data rate to unnecessary sensors indicating that our approach is sparsity-promoting, and an effective sensor selection heuristic.     

The generalized covering traveling salesman problem

In this paper we develop a problem with potential applications in humanitarian relief transportation and telecommunication networks. Given a set of vertices including the depot, facility and customer vertices, the goal is to construct a minimum length cycle over a subset of facilities while covering a given number of customers. Essentially, a customer is covered when it is located within a pre-specified distance of a visited facility on the tour. We propose two node-based and flow-based mathematical models and two metaheuristic algorithms including memetic algorithm and a variable neighborhood search for the problem. Computational tests on a set of randomly generated instances and on set of benchmark data indicate the effectiveness of the proposed algorithms.     

混合关系中的函数依赖及其相关规则

在实际应用中有这样一类关系数据库,其中数据项在某个属性上的取值本身又是一个关系。讨论这种混合关系中的函数依赖及其相应的相关规则具有一定的理论意义和实际应用价值。给出这种混合关系的形式定义、混合关系中4种类型的函数依赖关系以及相应的4种类型的相关规则;并给出混合关系到一般关系的转换,通过这个转换说明了混合关系与普通关系的联系及其差别。给出一个实际应用中的例子,来说明混合关系中的函数依赖和相关规则的形式多样性。     

Integrating Priority with Share in the Priority-Based Weighted Fair Queuing Scheduler for Real-Time Networks

The Weighted Fair Queuing (WFQ) scheduler has been closely studied due to its desirable properties of bandwidth guarantee and bounded delay. However, the queuing delay bound of a communication session is tightly coupled with the session's allocated service share. To receive a low queuing delay, a session must reserve a high share. In this paper, we study a new fair queuing algorithm called Priority-based Weighted Fair Queuing (PWFQ). PWFQ combines a session's allocated share to achieve the bandwidth guarantee and the session's priority to adjust the delay bound inside a sliding window. The new algorithm decouples the delay from the service share so that a session with a low share but a high priority may still receive a small delay. We analyze the worst-case delay bound of PWFQ and propose a simple algorithm to assign session priorities.     

Design of phononic materials/structures for surface wave devices using topology optimization

We develop a topology optimization approach to design two- and three-dimensional phononic (elastic) materials, focusing primarily on surface wave filters and waveguides. These utilize propagation modes that transmit elastic waves where the energy is contained near a free surface of a material. The design of surface wave devices is particularly attractive given recent advances in nano- and micromanufacturing processes, such as thin-film deposition, etching, and lithography, which make it possible to precisely place thin film materials on a substrate with submicron feature resolution. We apply our topology optimization approach to a series of three problems where the layout of two materials (silicon and aluminum) is sought to achieve a prescribed objective: (1) a grating to filter bulk waves of a prescribed frequency in two and three dimensions, (2) a surface wave device that uses a patterned thin film to filter waves of a single or range of frequencies, and (3) a fully three-dimensional structure to guide a wave generated by a harmonic input on a free surface to a specified output port on the surface. From the first to the third example, the resulting topologies increase in sophistication. The results demonstrate the power and promise of our computational framework to design sophisticated surface wave devices.     

Dense Mapping From an Accurate Tracking SLAM

In recent years, reconstructing a sparse map from a simultaneous localization and mapping (SLAM) system on a conventional CPU has undergone remarkable progress. However, obtaining a dense map from the system often requires a high-performance GPU to accelerate computation. This paper proposes a dense mapping approach which can remove outliers and obtain a clean 3D model using a CPU in real-time. The dense mapping approach processes keyframes and establishes data association by using multi-threading technology. The outliers are removed by changing detections of associated vertices between keyframes. The implicit surface data of inliers is represented by a truncated signed distance function and fused with an adaptive weight. A global hash table and a local hash table are used to store and retrieve surface data for data-reuse. Experiment results show that the proposed approach can precisely remove the outliers in scene and obtain a dense 3D map with a better visual effect in real-time.      

基于草图交互的个性化服装生成方法

以建立和交互修改三维服装草图为设计手段,提出在三维人体模型上生成三维个性化服装的参数化造型方法．服装草图由2种基本几何元素组成：体现人体围度信息的封闭样条曲线和体现人体在高度方向上曲面形状过渡的不封闭样条曲线．将服装草图约束分为2类4种：一类是体现服装宽松程度的人体与服装曲面之间的间隙约束;另一类是服装几何元素本身之间的共点、共面与对称约束．从人体的特征点出发,通过间隙约束生成服装草图的几何元素;在共点、对称和共面约束下,由服装草图几何元素建立拓扑结构为四边网格的服装草图．服装草图的交互修改是草图约束维护的过程,构建侧视图、正视图、断面图3个视图组成草图修改平台,在平台上交互编辑特征曲线．服装曲面则以三维草图为框架,通过对四边网格双线性Coons曲面插值生成．提供的设计方法使服装的造型变得简洁、灵活．     

Catadioptric Projective Geometry

Catadioptric sensors are devices which utilize mirrors and lenses to form a projection onto the image plane of a camera. Central catadioptric sensors are the class of these devices having a single effective viewpoint. In this paper, we propose a unifying model for the projective geometry induced by these devices and we study its properties as well as its practical implications. We show that a central catadioptric projection is equivalent to a two-step mapping via the sphere. The second step is equivalent to a stereographic projection in the case of parabolic mirrors. Conventional lens-based perspective cameras are also central catadioptric devices with a virtual planar mirror and are, thus, covered by the unifying model. We prove that for each catadioptric projection there exists a dual catadioptric projection based on the duality between points and line images (conics). It turns out that planar and parabolic mirrors build a dual catadioptric projection pair. As a practical example we describe a procedure to estimate focal length and image center from a single view of lines in arbitrary position for a parabolic catadioptric system.     

SSME 在欧洲的教学：Porto和Masaryk大学的一个联合硕士培养计划

Service Science, Engineering and Management (SSME) is emerging as a new discipline and several universities have been evolving or creating courses/programs to educate for the needs of the service fields of the economy. The University of Porto started in 2007 a master program in Service Engineering and Management, and Masaryk University started in 2008 a program in Service Science, Management, and Engineering. Both programs concentrate on services that are supported by technology, in particular information and communication technologies. This paper presents a summary of both programs and a proposal for a joint 2 year master program involving the two universities that is expected to start in 2010. Students in this program will take courses in the two universities, and lecturers will be involved in joint research projects. Individual students will have a semester research or applied project in a European service organization, being supervised by a lecturer or a researcher from each universities. It is expected that graduates will understand technological, organizational and cultural aspects of the diverse businesses in a wide European context and will be ready for service requirements of this century.