Resilience Articulation Point (RAP): Cross-layer dependability modeling for nanometer system-on-chip resilience

The Resilience Articulation Point (RAP) model aims at provisioning researchers and developers with a probabilistic fault abstraction and error propagation framework covering all hardware/software layers of a System on Chip. RAP assumes that physically induced faults at the technology or CMOS device layer will eventually manifest themselves as a single or multiple bit flip(s). When probabilistic error functions for specific fault origins are known at the bit or signal level, knowledge about the unit of design and its environment allow the transformation of the bit-related error functions into characteristic higher layer representations, such as error functions for data words, Finite State Machine (FSM) state, macro-interfaces or software variables. Thus, design concerns at higher abstraction layers can be investigated without the necessity to further consider the full details of lower levels of design. This paper introduces the ideas of RAP based on examples of radiation induced soft errors in SRAM cells, voltage variations and sequential CMOS logic. It shows by example how probabilistic bit flips are systematically abstracted and propagated towards higher abstraction levels up to the application software layer, and how RAP can be used to parameterize architecture-level resilience methods.     

Dielectrophoretic modeling of the dynamic carbon nanotube network formation in viscous media under alternating current electric fields

The dynamic formation of carbon nanotube (CNT) networks in liquids under the application of an alternating current electric field is investigated using the effective dipole modeling approach. Three mechanisms are investigated by a set of three independent nonlinear differential equations derived from dielectrophoretic theory, viz. CNT rotation, CNT-to-CNT Coulombic interactions, and CNT migration towards an electrode. The models consider the effect of the electric field magnitude and frequency, the CNT’s concentration and aspect ratio, and the viscosity of the surrounding medium. A layer at the CNT/liquid interface is included and the effect of such a layer’s permittivity, electrical conductivity and thickness is investigated. Modeling predictions allow the reconstruction of the dynamic sequence of events leading to an aligned CNT network, which strongly depends on the CNT’s aspect ratio and concentration. Experimental trends regarding the effect of frequency can only be captured by considering an interface layer in the model.     

Large-scale simulations and performance evaluation of connected cars - A V2V communication perspective

Performance evaluation is integral to the vast majority of research on Vehicle-to-Vehicle (V2V) technology enabled connected cars. To validate ideas and concepts, researchers have been continuously striving towards the higher accuracy of simulation-based performance evaluation. However, many state-of-the-art network simulators lack comprehensive physical (PHY) layer models. More often, simplified representations of vehicular channel characteristics are used to achieve a trade-off between accuracy and performance. Vehicular channel modeling is a highly complex task because of its unique properties, for example, higher carrier frequency, rapid fluctuations in vehicular channels due to moving scatterers, and propagation in horizontal plane instead of a vertical plane with diffraction and reflection. Efficiently incorporating vehicular channel details into a single network simulator is infeasible; instead, a chain of simulation tools are used together. In this paper, we proposed a two-stage simulation framework which combines several layers of simulation tools into two distinct stages. During the first stage, a Geometry-based vehicular propagation model is used to characterize received signal strength among transmitter-receiver pairs. For this purpose, metropolitan area-wide 2.5D building geometry data and vehicular mobility traces are employed to represent the real-world environment. Subsequently, the output from the first stage is collected and fed as an input to the network simulator. Through extensive simulation-based studies, we analyze the difference between the proposed framework and standard propagation models implemented in the network simulator and their impact on the network-level performance metrics such as packet loss rate (PLR), throughput, latency, and jitter.     

Preparation and characterization of the anti-virus and anti-bacteria composite air filter materials

The anti-virus and anti-bacteria active components were extracted from some Chinese medicine,such as the honeysuckle,forsythia and the licorice.Using a w/o/w emulsion method,the active components were fabricated to uniform particulate microcapsule with sustained-release properties.The polypropylene punched felt was finished with the finishing agent of microcapsule,nano ZnO and TiO 2 and polymer adhesive,and the composite air filter with anti-virus and anti-bacteria properties were formed,staphylococcus aureus,colibacillus and candida albicans were applied to antibacterial experiments.The results indicate that the anti-bacteria rate are all 100%,and the virus inactivation rate also reaches 100% to pandemic influenza A virus.     

The effect of heat treatment on the strength and toughness of carbon fiber/silicon carbide composites with different pyrolytic carbon interphase thicknesses

The effect of heat treatment on the strength and toughness of carbon fiber/silicon carbide composites (C/SiC) with different pyrolytic carbon (PyC) interphase thicknesses was investigated. It was found that as the heat treatment temperature (HTT) increases to 1900 °C, the strength and toughness of a low strength specimen (LSS, thin PyC ≈40 nm) increase by as much as 43.2% and 274.0%, while those of a high strength specimen (HSS, thick PyC ≈140 nm) show decreases of 25.1% and 14.8%, respectively. The elastic moduli of both LSS and HSS monotonically decreased with increasing HTT while the failure strains always became larger regardless of the initial interfacial bonding strengths (IBS). The mechanisms involved in the heat treatment of the C/SiCs were identified as (I) partial graphitization of the PyC that weakens the IBS, and (II) production of defects such as matrix cracks/delamination, interfacial debonding and fiber fracture/pull-out that lead to thermal residual stress relaxation. Thus heat treatment improves the strength and toughness of LSS with a relatively high IBS, but has a negative impact on both properties of HSS with a moderate IBS because the stress transfer efficiency onto the fibers is hindered by the too low IBS and the excessive stress relief.     

Sepic直流稳压器的设计

设计了一种输入交流电压范围为130~300 V,输出12 V/8 A、工作频率为100 k Hz的Sepic直流稳压器,阐述了主电路的拓扑结构,并设计了输入保护电路、辅助电源电路、PWM控制电路、光耦隔离驱动电路与输出过压、过流保护电路,应用反馈手段和脉宽调制技术实现电压、电流的稳定。     

基于1394b总线仿真设备的WDM驱动开发

基于解决1394b和PCI的跨速率条件下通信数据易丢失,软硬件交互产生误码的目的。本文采用WDM(波分复用)驱动的串行处理操作来保护硬件;采用内核态线程保证数据传输的确定性;采用DMA(直接内存存取)保证数据的实时性;采用循环队列的模式保证数据传输的可靠性;采用乒乓原理保证硬件和软件交互的准确性等。通过实验验证,该驱动程序实现了软硬件的协调工作、提高了软件对硬件操作的操作安全性、提高了传输数据的可靠性以及实时性等。     

Effect of enhanced interfacial reaction on the microstructure,phase transformation and mechanical property of Ni–Mn–Ga particles/Mg composites

This study investigated the microstructure, phase transformation and mechanical property of Ni–Mn–Ga particles/Mg composites with a strong interfacial reaction between the particles and the matrix. The strong interfacial reaction was related to the large surface area and energy per unit volume of the flaky shape Ni–Mn–Ga particles that favors the reaction between the particles and matrix. The martensitic transformation behavior was largely weakened due to the interfacial reactions and thus the reduced volume fraction of Ni–Mn–Ga particles. The composites exhibited a much improved compressive strength and ductility in comparison with that of the Ni–Mn–Ga alloy. The compressive plasticity of the composites was decreased when the Ni–Mn–Ga particle content exceeded 40 wt%. In comparison with the Mg-composites with large size Ni–Mn–Ga particles, the composites with small size particles would have a much stronger interfacial reactions, which was detrimental to the phase transformation and mechanical ductility of the composites. The investigation results in this article could provide a reference for the design and preparation of the particles reinforced metal matrix functional composites.     

Probabilistic modeling of hybrid transition structures

Within lightweight structures, often Fiber Reinforced Plastics (FRP) are used in combination with metallic materials. Most of these hybrid structures are manufactured by established methods like riveting, bolting or adhesive bonding. In order to avoid disadvantages like drilled FRP or large bond areas, the development of hybrid transition structures compatible to loads and material properties is required. To fulfill the requirements for enhanced lightweight design, novel, integral joint concepts are currently designed, dimensioned and produced by using textile, welding and casting techniques.Three concepts are under investigation which consist of different materials (titanium and Ti-alloys, glass fibers), manufacturing methods (casting, welding, textile techniques) and geometries.Various phase boundaries, materials and influences of the manufacturing processes have to be investigated that influence the structural behavior and its failure. Based on the results of Finite Element Models on the meso scale, further modeling is performed to include effects like material uncertainties and/or process influences.In this paper, a probabilistic computation procedure based on local survival probabilities and distribution functions is proposed and investigated. This approach allows to model the complex global failure behavior for each component or its interfaces as well as the whole hybrid transition zone. It also shows the interactions and consequences of certain component changes within the hybrid transition zone. First computations are carried out and compared with experiments.