Modeling the forces of cutting with scissors

Modeling forces applied to scissors during cutting of biological materials is useful for surgical simulation. Previous approaches to haptic display of scissor cutting are based on recording and replaying measured data. This paper presents an analytical model based on the concepts of contact mechanics and fracture mechanics to calculate forces applied to scissors during cutting of a slab of material. The model considers the process of cutting as a sequence of deformation and fracture phases. During deformation phases, forces applied to the scissors are calculated from a torque-angle response model synthesized from measurement data multiplied by a ratio that depends on the position of the cutting crack edge and the curve of the blades. Using the principle of conservation of energy, the forces of fracture are related to the fracture toughness of the material and the geometry of the blades of the scissors. The forces applied to scissors generally include high-frequency fluctuations. We show that the analytical model accurately predicts the average applied force. The cutting model is computationally efficient, so it can be used for real-time computations such as haptic rendering. Experimental results from cutting samples of paper, plastic, cloth, and chicken skin confirm the model, and the model is rendered in a haptic virtual environment.     

Transmission line model for field distribution in microstrip linefed H-slots

A method for finding the electric field distribution of microstrip line fed H-slots is described. A transverse resonance technique is first applied to find a second-order approximation of the slot propagation constant, which is then used in the transmission line model for the H-slot. The proposed model for the field distribution can be applied to the transmission line and cavity model analysis of H-slot coupled microstrip antennas     

Large-signal microwave characterization of AlGaAs/GaAs HBT's basedon a physics-based electrothermal model

A physics-based multicell electrothermal equivalent circuit model is described that is applied to the large-signal microwave characterization of AlGaAs/GaAs HBT's. This highly efficient model, which incorporates a new multifinger electrothermal model, has been used to perform dc, small-signal and load-pull characterization, and investigate parameter-spreads due to fabrication process variations. An enhanced Newton algorithm is presented for solving the nonlinear system of equations for the model and associated circuit simulator, which allows a faster and more robust solution than contemporary quasi-Newton nonlinear schemes. The model has been applied to the characterization of heterojunction bipolar transistor (HBT) microwave power amplifiers     

交互式多模型在警戒类雷达跟踪中的应用研究

用CV模型、CA模型、Singer模型以及"当前"统计模型两两交互的多模型算法来处理某警戒雷达的两条航迹,并且把其仿真得出的一系列结果与目前常用的处理航迹滤波的Kalman(Singer模型)算法进行比较。研究了对不同的飞行轨迹选择什么样的模型组合可以最大提高滤波的精度,讨论了模型的优选问题。     

一种复杂的动态实时强协同的协作系统的研究

经典的协作模型不能满足复杂的协作应用在动态性、实时性以及分布决策的强协同等方面的需求.本文针对复杂的动态实时强协同的协作系统,研究并构造了与之相适应的协作模型DReaSCoM(Dynamic Real-time Strong Cooperation Model).该模型在扩展的层次式"群簇"结构中实现了群体内和群体间纵横交错的强协同协作,提高了系统的协作效率和容错能力,具有良好的应用价值.     

Modeling for bridging faults in nMOS combinational circuits

A transistor level model that fully describes the logical behavior of a circuit in the presence of bridging faults is presented for the nMOS combinational circuits. The proposed model is suitable for the circuits having static enhancement/depletion (E/D) load. Thus, the model can be applied to circuits like pseudo nMOS and CMOS non-threshold-logic (NTL). The model employs a logic transistor function (LTF) to examine the behavior of such circuits. The LTF model developed earlier for stuck faults in nMOS circuits is extended for bridging faults. Algorithms that were developed for the stuck faults in pseudo nMOS combinational circuits can be applied to generate the test vectors for bridging faults.     

面向车辆盲区防撞系统的交通目标智能检测

交通目标智能检测是车辆盲区智能防撞系统中的基础技术,该技术的研究和应用对降低交通事故损失具有重要意义.本文面向车辆盲区防撞系统设计的交通目标智能检测,其在基础模型中融合了两个性能提升策略.将该模型应用于国内和国外道路场景检测数据集,以验证模型在所有范围和近距离目标的检测性能.实验结果表明该模型可以对近距目标表现出较高的...     

TMN as applied to the GSM network

Reviews some of the guiding principles of TMN that were applied, or consciously not applied, to the development of GSM network management. The organization of the work within the sub-technical committee and the resultant organization of the specifications are described. The article also introduces the model for the management of a GSM network, as well as some of the philosophy behind this model. Certain aspects of this model are described in greater detail to illustrate its use     

Random Group Recommendation Model Based on Fuzzy Clustering

The group recommendation system is a viral requirement for the Internet service provider to provide recommendation services for all the users in a group. Due to the shared or different interests among users in the group, it is difficult for traditional personal recommendation algorithms to predict items that can meet the requirements of all the users in the group. In this paper, a random group recommendation model is proposed to recommend the top K most appealing items for all the users in a random group. By analyzing item ratings of all the users in the group, the recommendation model can abstract the group as a virtual user. Then a personal recommendation algorithm is applied to suggest the top K most appealing items for the virtual user. And the preference score and fuzzy clustering algorithm based on multiclass are applied to optimize the recommendation result of the group recommendation model. Finally, the MovieLens-100K dataset is applied to verify the efficiency of the recommendation model. The experimental results show that the items recommended by the proposed group recommendation model are more popular for all the users in the group than the items recommended by traditional group recommendation algorithms.     

A stochastic model for the interconnection topology of digitalcircuits

Rent's rule has been successfully applied to a priori estimation of wire length distributions. However, this approach is very restrictive: the circuits are assumed to be homogeneous. In this paper, recursive clustering is described as a more advanced model for the partitioning behavior of digital circuits. It is applied to predict the variance of the terminal count distribution. First, the impact of the block degree distribution is analyzed with a simple model. A more refined model incorporates the effect of stochastic self similarity. Finally, the model is further extended to describe the effects of heterogeneity. This model is a promising candidate for more accurate a priori estimation tools     

CORBA分布式网管安全问题的解决

通过比较三种CORBA应用安全防护模型，结合Tcp Proxy、CORBA安全服务，SSL的新型的安全防护模型能为CORBA应用提供全面的安全防护。     

A Control-Oriented and Physics-Based Model for Ionic Polymer--Metal Composite Actuators

Ionic polymer-metal composite (IPMC) actuators have promising applications in biomimetic robotics, biomedical devices, and micro/nanomanipulation. In this paper, a physics- based model is developed for IPMC actuators, which is amenable to model reduction and control design. The model is represented as an infinite-dimensional transfer function relating the bending displacement to the applied voltage. It is obtained by exactly solving the governing partial differential equation in the Laplace domain for the actuation dynamics, where the effect of the distributed surface resistance is incorporated. The model is expressed in terms of fundamental material parameters and actuator dimensions, and is thus, geometrically scalable. To illustrate the utility of the model in controller design, an H_infin controller is designed based on the reduced model and applied to tracking control. Experimental results are presented to validate the proposed model and its effectiveness in real-time control design.     

Visco-elastic-plastic properties and constitutive modeling ofunderfills

The thermo-mechanical testing of HYSOL PP4526 underfill is reported, including the details of sample preparation and test procedures. It is found that the Young's modulus of the underfill depends on both temperature and applied strain rate. The constitutive framework proposed for solder alloys has been applied successfully to model the thermo-mechanical properties of the underfill in this paper. Excellent agreement between model predictions and experimental data is achieved, The test data and calibrated constitutive model can be used for the analysis and design of advanced electronic packages with underfills such as flip-chip packages     

Novel Closed-Form Model for Multiple-State Quantum-Dot Semiconductor Optical Amplifiers

Novel closed-form model for multiple-state quantum-dot semiconductor optical amplifiers (QD-SOAs) is derived. The model takes into account the effect of the ground state, excited state and the wetting layer. The model is simple, accurate and exhibits negligible computational time compared with numerical simulation. In addition, the derived model is valid for arbitrary applied current and input photon density and is interesting for device design and optimization. Analytical expressions for the optical gain, effective saturation density, maximum output density and the transparency current are also derived. Our model revealed that the effective saturation density of QD-SOAs strongly depends on the photon density and the applied current.     

A statistical model for the error bounds of an active phased arrayantenna for SAR applications

A model for the theoretical error bounds for the radiometric calibration of SAR imagery is described. The model is then applied utilizing the radar system parameters that will be used in the project PHARUS (Phased Array Universal SAR), a Dutch polarimetric airborne C -band universal SAR, which is currently under construction. An error model for the phased array antenna pattern is presented. This model was applied to a 16×8 phased array antenna to determine the influence of errors in the T/R modules and angle variations of the beam direction. For a wide range of variances the model is in good agreement with the exact solution, but with far less computer effort. Other, more complicated, antennas can be analyzed in a straightforward way. The model can be used as a design tool for digital phased array radar     

Modeling the Rate-Dependent Durability of Reduced-Ag SAC Interconnects for Area Array Packages Under Torsion Loads

Solder durability models frequently focus on the applied strain range; however, the rate of applied loading, or strain rate, is also important. In this study, an approach to incorporate strain rate dependency into durability estimation for solder interconnects is examined. Failure data were collected for SAC105 solder ball grid arrays assembled with SAC305 solder that were subjected to displacement-controlled torsion loads. Strain-rate-dependent (Johnson–Cook model) and strain-rate-independent elastic–plastic properties were used to model the solders in finite-element simulation. Test data were then used to extract damage model constants for the reduced-Ag SAC solder. A generalized Coffin–Manson damage model was used to estimate the durability. The mechanical fatigue durability curve for reduced-silver SAC solder was generated and compared with durability curves for SAC305 and Sn-Pb from the literature.     

How to quantify and predict long term multiple stress operation: Application to Normally-Off Power GaN transistor technologies

The present paper is implementing a numerical application of the Boltzmann–Arrhenius–Zhurkov (BAZ) model and relates to the statistic reliability model derived from the Transition State Theory paradigm. It shows how the quantified tool can be applied to determine the associated effective activation energy. The unified multiple stress reliability model for electronic devices is applied to Normally-Off Power GaN transistor technologies to quantify and predict the reliability figures of this electronic type of product when operating under multiple stresses in an embedded system operating under such harsh environment conditions as set for Aerospace, Space, Nuclear, Submarine, Transport or Ground application.     

A computer-aided approach to the structural analysis and modification of a large circulatory system model

The purpose of this study is to show an approach to making an intelligent support system for understanding and modifying a large circulatory system model using techniques of system analysis. Structural analysis makes it possible to visualize hierarchies of Coleman's circulatory model Human. Two techniques are successively applied for structural analysis, model reduction and graph analysis by interpretative structural modeling (ISM). First, the analysis for model reduction removes input-output relations with an input-output gain less than a given threshold, and second, the ISM technique applied to the reduced model of Human provides hierarchical directed graphs. The proposed approach: 1) enables visualization of a hierarchy graph of cause and effect relations of the large circulatory model, 2) suggests control and diagnostic information to the model by tracing back a path in the hierarchy, and 3) allows the user to modify the circulatory model. The efficiency and performance of the proposed approach demonstrates technical indications of success in analyzing and justifying experimental evidences with the online help of the system.     

On the transient response of organic electrochemical transistors

We present a universal model for the transient drain current response in organic electrochemical transistors (OECTs). Using equivalent circuits and charge injection physics, we are able to predict the drain current in OECT devices upon application of a gate voltage input. The model is applicable to both plain and membrane-functionalized devices, and allows us to extract useful physical quantities such as resistances and capacitances, which are related to functional properties of the system. We are also able to use the model to reconstruct the magnitude and shape in time of an applied voltage source based on the observed drain current response. This was experimentally demonstrated for drain current measurements under an applied action potential.     

中高层大气临边红外辐射的LTE与non-LTE模拟对比

利用战略高空辐亮度代码(Strategic high-altitude radiance code, SHARC) 和通用大气辐射传输代码 (Combined atmospheric radiative transfer, CART) 模拟分析中高层大气临边红外辐射的算法适用范围。 通过模拟结果的对比,初步验证了CART临边模式的有效性。模拟结果表明,在主要的红外波段上,至少45 km以 下的平流层区域内临边红外辐亮度的计算都可以采取局域热力学平衡模式(Local thermodynamics equilibrium, LTE);不同的红外波段在不同的大气条件下,需要采用非局域热力学平衡模式 (Non-local thermodynamics equilibrium, non-LTE)的高度不同,其中15 $\mu$m波段在至少80 km的切点 高度以下都可以使用LTE模式模拟,但是对于CO$_2$ 4.3 $\mu$m带主导的3$\sim$5 $\mu$m波段和O$_3$ 9.6 $\mu$m带 主导的8$\sim$12 $\mu$m波段,在中间层的多数区域内就必须采用non-LTE模式。