Distributed autonomic management: An approach and experiment towards managing service-centric networks

This paper describes a novel approach for managing service-centric communications networks called distributed autonomic management (DAM). Current approaches to network management employ the client/server model, cooperative stationary agents, and/or non-intelligent mobile agents. The DAM model consists of communities of mobile and stationary intelligent agents in collaboration. We discuss an experiment with DAM and proceed to discuss outstanding research issues. The DAM approach uses the properties and characteristics of autonomic systems in support of managing service-oriented communications networks and protecting e-commerce and business enterprises against cyber terrorism.     

3D格斗游戏中碰撞检测技术的研究和实现

认真分析了3D游戏软件制作中动态物体之间的碰撞检测方法,重点讨论了基于骨骼系统和蒙皮技术创建的3D格斗游戏人物模型之间的碰撞检测技术。提出了由骨骼系统创建人物碰撞模型,并基于新的碰撞模型实现了碰撞检测方法。实验和分析均表明,该方法在碰撞检测中便于确定人物身体部位且效率高,有很好的理论意义和应用推广价值。     

液压脉冲试验台建模与仿真研究

针对液压脉冲试验台要能可靠可控地产生脉冲波形这个关键技术问题,以管道－容腔物理模型为基础,首次建立了斜坡输入模型,推导出了斜坡响应输出表达式。计算结果表明斜坡输入模型的超调量最大为63.7%。根据阶跃输入和斜坡输入模型,从理论上分析得出了在斜坡输入时间不大于系统振荡周期十分之一时,斜坡输入可以作为阶跃输入来处理。利用Matlab和液电比拟方法对阶跃模型、斜坡模型进行了数字仿真,仿真结果表明通过调整容腔体积、管道长度以及管道直径等系统参数,能产生符合标准的脉冲波形。     

Preparation and capacitance performance of nitrided lithium titanate nanoarrays

Nitrided lithium titanate (N-Li₄Ti₅O₁₂) nanoarrays with nanowire and nanotube structures were designed as the electrode materials of lithium-ion supercapacitor for electrochemical energy storage. Two types of TiO₂ nanoarrays were used as the precursor which involved TiO₂ nanowire array prepared by hydrothermal process and TiO₂ nanotube array prepared by anodization process. Li₄Ti₅O₁₂ nanoarrays were formed through hydrothermal reaction or sonochemical reaction of TiO₂ nanoarrays with lithium hydroxide and then calcination treatment process. Finally, N-Li₄Ti₅O₁₂ nanoarrays were formed through nitriding treatment of Li₄Ti₅O₁₂ using ammonia as nitrogen source. The electroactive N-Li₄Ti₅O₁₂ nanowire array and nanotube array exhibited the specific capacitance of 607.2 F g⁻¹ and 814.4 F g⁻¹ at a current density of 1 A g⁻¹, respectively. The corresponding capacitance retention was determined to be 92.1% and 94.2% after 1000 cycles at high current density of 5 A g⁻¹. The corresponding capacitance still kept 182.9 and 352.1 F g⁻¹ at much higher current density of 20 A g⁻¹, presenting reasonable rate capability for N-Li₄Ti₅O₁₂ nanoarrays. The improved capacitance performance of N-Li₄Ti₅O₁₂ nanotube array was ascribed to the more amount of TiN and more accessible nanotube surface area, which contributed to the improved conductivity and fast diffusion of electrolyte ions on the surface of electrode. Both N-Li₄Ti₅O₁₂ nanowire array and nanotube array with well-aligned integrative structure exhibited an excellent cycling stability during continuous charge/discharge process. Well-designed N-Li₄Ti₅O₁₂ nanoarrays with high capacitance, good cycling stability and rate capability presented the promising application as feasible electrode materials of lithium-ion supercapacitors for the energy storage.     

Hybrid TFET-MOSFET circuit: A solution to design soft-error resilient ultra-low power digital circuit

In this work, to increase the reliability of low power digital circuits in the presence of soft errors, the use of both III-V TFET- and III-V MOSFET-based gates is proposed. The hybridization exploits the facts that the transient currents generated by particle hits in TFET devices are smaller compared to those of the MOSFET-based devices while MOSFET-based gates are superior in terms of electrical masking of soft errors. In this approach, the circuit is basically implemented using InAs TFET devices to reduce the power and energy consumption while gates that can propagate generated soft errors are implemented using InAs MOSFET devices. The decision about replacing a subset of TFET-based gates by their corresponding MOSFET-based gates is made through a heuristic algorithm. Furthermore, by exploiting advantages of TFETs and MOSFETs, a hybrid TFET-MOSFET soft-error resilient and low power master-slave flip-flop is introduced. To assess the efficacy of the proposed approach, the proposed hybridization algorithm is applied to some sequential circuits of ISCAS’89 benchmark package. Simulation results show that the soft error rate of the TFET-MOSFET-based circuits due to particle hits are up to 90% smaller than that of the purely TFET-based circuits. Furthermore, energy and leakage power consumptions of the proposed hybrid circuits are up to 79% and 70%, respectively, smaller than those of the MOSFET-only designs.     

The effect of non-equilibrium condensation on the drag coefficient in a transonic airfoil flow

In this study,a transonic flow past NACA0012 profile at angle of attack α=00 whose aspect ratio AR is 1.0 with non-equilibrium condensation is analyzed by numerical analysis using a TVD scheme and is investigated using an intermittent indraft type supersonic wind tunnel.Transonic flows of 0.78-0.90 in free stream Mach number with the variations of the stagnation relative humidity(Φ0)are tested.For the same free stream Mach number,the increase in Φ0 causes decrease in the drag coefficient of profile which is composed of the drag components of form,viscous and wave.In the case of the same M∞ and T0,for more than Φ0=30%,despite the irreversibility of process in non-equilibrium condensation,the drag by shock wave decreases considerably with the increase of Φ0.On the other hand,it shows that the effect of condensation on the drag coefficients of form and viscous is negligible.As an example,the decreasing rate in the drag coefficient of profile caused by the influence of non-equilibrium condensation for the case of M∞=0.9 and Φ0=50% amounts to 34%.Also,it were turned out that the size of supersonic bubble(that is,the maximum height of supersonic zone)and the deviation of pressure coefficient from the value for M=1 decrease with the increase of Φ0 for the same M∞.     

建设项目n维编码体系集成模型研究

分析了建设项目集成化管理中信息传递存在的问题,考虑不同管理领域将产生不同的信息分解体系约束,建立了n维编码体系集成模型.通过建立各体系之间的关系映射,集成各类信息,便于项目高层管理人更的决策分析.通过算例分析,验证了该模型的可操作性.     

智能冷热量度系统

利用8XC552单片机及其外围电路组成冷热量度系统，并论述了该系统的工作原理、硬件及软件的组成和应用效果。     

Highly efficient distributed generation and high-capacity energy storage

With the growing amount of decentralized power production the design and operation of the grid has to be reconsidered. New problems include the two-way flow of electricity and maintaining the power balance given the increased amount of uncertain and fluctuating renewable energy sources like wind and solar that deliver electricity to the grid.Solution directions are the development of smart grids, demand side management, virtual power plants and storage of electricity. These are directions that, rightly so, are already attracting a lot of attention and R&D funding. In this paper critical issues are identified and specified. However, we will also explore new solution directions based on an integrative approach as proposed by the Dutch Royal Academy of Science foresight committee on renewable energy conversions. These alternative solutions include flexible coproduction and local production of chemicals and fuel that can also fulfill a storage function.     

An adaptive method for the Stefan problem and its application to endoglacial conduits

This paper concerns an adaptive finite element method for the Stefan one-phase problem. We derive a parabolic variational inequality using the Duvaut transformation. In each time-step we consider an adaptive algorithm based on a combination of the Uzawa method associated with the corresponding multivalued operator and a convergent adaptive method for the linear problem. We justify the convergence of the method. As an application we model an endoglacial conduit in which a phase change phenomenon takes place.