Design Methodology and Validity Verification for a Reactive Countermeasure Against EM Attacks

This paper presents a standard-cell-based semiautomatic design methodology for a new conceptual countermeasure against electromagnetic (EM) analysis and fault-injection attacks. The countermeasure, called the EM attack sensor, utilizes LC oscillators that react to variations in the EM field around a cryptographic LSI caused by a microprobe brought near the LSI. A dual-coil sensor architecture with digital calibration based on lookup table programming can prevent various microprobe-based EM attacks that cannot be thwarted by conventional countermeasures. All components of the sensor core are semiautomatically designed by standard electronic design automation tools with a fully digital standard cell library and hence minimum design cost. This sensor can therefore be scaled together with the cryptographic LSI to be protected. The sensor prototype is designed based on the proposed methodology together with a 128-bit-key composite AES processor in 0.18-\(\upmu \hbox {m}\) CMOS with overheads of only 2 % in area, 9 % in power, and 0.2 % in performance, respectively. The countermeasure has been validated against a variety of EM attack scenarios. In particular, some further experimental results are shown for a detailed discussion.     

The four-electrode resistivity technique in anisotropic media:theoretical analysis and application on myocardial tissue in vivo

Several aspects of the 4-electrode resistivity technique were studied with special emphasis on the theoretical determination of penetration depth and sample volume in anisotropic media such as (cardiac) muscle. Moreover, the presence of a thin disturbing layer on top of the medium under study was analyzed. A 4-electrode sensor was developed for the measurement of local myocardial resistivity in 2 orthogonal directions. The sensor was applied to the epicardium of anesthetized open chest dogs and, as an example, results are given on the frequency dependence (5-60 kHz) and the changes during the cardiac cycle of longitudinal and transverse myocardial resistivity     

Estimating one-dimensional models from frequency-domainelectromagnetic data using modular neural networks

An artificial neural network interpretation system is being used to interpret data from a frequency-domain electromagnetic (EM) geophysical system in near real time. The interpretation system integrates 45 separate networks in a data visualization shell. The networks produce interpretations at three different transmitter-receiver (Tx-Rx) separations for half-space and layered-Earth interpretations. Modular neural networks (MNNs) were found to be the only paradigm that could successfully perform the layered-Earth interpretations. An MNN with 16 inputs, five local experts, each with seven hidden processing elements, and three outputs was trained on 4795 patterns for 200 epochs. For two-layer models with a resistivity contrast greater than 2:1, resistivity estimates had greater than 96% accuracy for the first-layer resistivity, greater than 98% for the second-layer resistivity, and greater than 96% for the thickness of the first layer. If the contrast is less than 2:1, the resistivity accuracies are unaffected but thickness estimates for layers less than 2 m are unreliable. A Tx-Rx separation of 16 m with maximum depth of penetration of 8 m was assumed for the example cited     

A Numerical Evaluation of the Limitations of the Thin-Sheet Approximation

One of the prime difficulties encountered in magnetotellurics involves adequately modeling the conducting earth when lateral conductivity variations are present. A common modeling technique that is used when the horizontal conductivity variations are of limited vertical extent is known as the thin-sheet approximation. The validity of the thin-sheet approximation is examined by comparing the surface impedance obtained for a horizontally layered earth model and its thin-sheet equivalent. Only a homogeneous thin sheet is considered; thus, the effects on the thin-sheet approximation of horizontal conductivity variations within the thin sheet are not evaluated. For the homogeneous thin sheet, it is found that generally the thinsheet approximation yields less than 10-percent error in the surface impedance for frequencies such that the thickness of the layer being modeled by the thin sheet is less than 0.3 of a skin depth in the layer, although in some instances the error approaches ten percent at larger ratios of layer thickness to layer skin depth. The presence of a shallow, highly conductive substratum does not adversely affect the validity of the approximation in many cases, contrary to what was previously believed. In those instances where the conductive substratum does have an effect, it is to reduce the ratio of layer thickness to layer skin depth at which the approximation is valid, and not to invalidate the procedure altogether.     

条形半导体激光器注入电流的横向分布

用双连通域内的保角变换方法解二维拉普拉斯方程，得到了条形半导体激光器注入电流密度的横向分布。研究了在电阻层的电阻率比较大的情况下，中央激活区不同宽度和不同电极宽度时注入电流密度的横向分布。如果中央激活区宽度小条形电极宽度，注入电流密度在中央激活区内近似为常数，而在中央激活区外很快地衰减。     

Dependence of apparent resistance of four-electrode probes on insertion depth

The apparent resistance of a finite-thickness layer measured with a four-electrode plunge probe depends on the electrode insertion depth, electrode spacing, and layer thickness, as well as the resistivity ratio of an underlying layer. A physical model consisting of air, a saline solution layer, and an agar layer simulates the real situation of resistivity measurement. The saline layer represents the finite-thickness layer whose resistivity is to be measured by a plunge electrode probe, and the agar layer represents an underlying perturbing layer. A micropositioner controls the insertion depth of the four electrodes into the saline solution. With the apparent resistance measured on a semi-infinite-thickness layer of saline solution as standard, measurement results show decreasing apparent resistance and increasing error with increasing electrode insertion depth. This information is important for correct measurement of myocardial resistivity in vivo and in vitro.     

Reference system for vehicular lateral guidance

A lateral reference/sensor configuration is described which appears to have overcome the problems caused by steel reinforcing in concrete. Previously used reference/sensor systems performed as predicted on nonreinforced road surfaces but exhibited gain and lateral offset variations as a function of distance along a steel-reinforced highway. An automatic lateral guidance system using the new configuration has been successfully tested on continuously reinforced concrete at speeds up to 80 mi/h.     

基于红外光反射的雪深检测传感器研究与应用

冬季河流湖泊冰盖表面的积雪深度监测是水文信息化领域的一项切实需求,基于空气、积雪和冰盖三种介质对红外光的传输特性差异,设计了一种可以连续实时对积雪深度进行定点检测的传感器。传感器及检测系统于2016年12月初在我国黑龙江上游漠河县江段进行了现场安装与实验测试,通过与传统对射式雪深检测传感器以及当地水文站人工测试结果对比,基于红外光反射特性的雪深检测传感器灵敏度更高,能更准确反映出积雪深度的变化过程,且具有体积小,布设安装方便等特点,为高寒地区野外恶劣环境下积雪深度的定点高精度检测提供了一种新的解决方法和技术装备。     

Laboratory backscatter measurements over urea ice with a snow coverat Ku band

Indoor laboratory facilities were used to measure radar backscatter at Ku band (13.9 GHz) over urea ice, which has been shown to be structurally similar to sea ice. Data were collected at angles of incidence from normal to 55°, over very thin (0 to 9 cm) ice, snow-covered ice, and ice with a hooded snow cover. The laboratory proved to be useful in creating and controlling specific physical properties of ice while keeping all other variables constant, a difficulty with measurements collected in the field. It was found that surface scattering and the dielectric constant are the dominant factors that cause variations (up to 15 dB) in the measured backscatter. The addition of a snow cover increased the surface roughness of the smooth ice, increasing the backscatter at 20° incidence angle by about 11 dB and decreasing the backscatter at normal incidence by about 6 dB. The subsequent flooding of this snow layer increased the backscatter at all angles of incidence due to the increased dielectric constant of the wet slush layer. These results indicate the importance of the snow layer in influencing the surface characteristics of the ice sheet, which in turn modifies the backscattered signal     

结构型铁砂基复合电波吸收体研究

由天然尖晶石铁氧体（铁砂）为基制备的复合电波吸收材料，在７～１２ＧＨｚ，吸收率Ａ为１２～２７ｄＢ，匹配厚度ｄ为１．４ｍｍ。将几种铁砂基复合吸收材料制成双层结构电波吸收体，Ａ最大达４０ｄＢ，匹配厚度ｄ为１ｍｍ，频带增宽。这是一种廉价的吸收材料，其造价仅为一般铁氧体吸收材料的１／１０，有较大实用价值。     

A New Inversion Technique for Apparent Resistivity Measurements

A new algorithm for interpreting apparent earth resistivity data obtained from depth sounding measurements is presented. The method is based on fitting the data to an N layer earth model with equal layer heights h where h is equal to the required depth resolution. The spectral reflection coefficient at the earth's surface for the model used is derived as a ratio of two polynomials, the coefficients of which are a function of the resistivity ratios of adjacent layers. This provides the theoretical basis for inferring the model parameters. Measures for improving numerical stability are suggested and applied to a few examples. Results show that the present algorithm is most suited for continuously varying resistivity depth profiles.     

水平分层大地电导率对倾斜通道LEMP 场影响研究

为了得到水平分层条件下,放电通道倾斜角度、大地电导率以及分层土壤厚度对倾斜通道雷电电磁脉冲(LEMP)场的影响规律,在差分条件下对三维直角坐标系的倾斜放电通道加源方程进行了推导,在此基础上利用时域有限差分(FDTD)法对倾斜通道雷电电磁场进行了建模。研究结果表明,当放电通道倾斜角度改变时,雷电电磁场峰值会随着倾斜角度的增加而出现明显的上升,同时观测点与雷击点之间的距离越大倾斜角度对电磁场的影响越明显。当电导率发生改变时,上层电导率主要影响电磁场的峰值,而底层土壤电导率主要影响电磁场的下降沿陡度和波尾幅值,对电磁场峰值影响较小,基本可以忽略。此外,电场波形的下降沿陡度随土壤上层电导率的减小而增加,随下层电导率的减小而降低。当上层土壤厚度改变时,在影响深度范围内电场波尾幅值会随着上层厚度的增加而增加,但电磁场峰值基本不受影响,而且随着水平距离的增加表层土壤的影响深度在不断加大。     

HF Radio Wave Transmission over Sea Ice And Remote Sensing Possibilities

Ground wave propagation is analyzed for a path where sea water is covered by a uniform layer of sea ice. The source is taken to be a vertical electric dipole on or above the ice layer. The solution indicates that a trapped surface wave is significant at short ranges while, at longer ranges, the usual ground wave modes are dominant. The resulting interference pattern may produce rapid variations of the field at intermediate ranges. These characteristics, as well as the height dependence of the observed field strength, are strongly dependent on the thickness of the ice layer.     

Evaluation of late summer passive microwave Arctic sea iceretrievals

The melt period of the Arctic sea ice cover is of particular interest in studies of climate change due to the albedo feedback mechanisms associated with meltponds and openings in the ice pack. The traditionally used satellite passive microwave sea ice concentration algorithms have deficiencies during the summer months due to the period's highly variable surface properties. A newly developed ice concentration algorithm overcomes some of these deficiencies. It corrects for low ice concentration biases caused by surface effects through the use of 85 GHz data in addition to the commonly used 19 and 37 GHz data and, thus, the definition of an additional ice type representing layering and inhomogeneities in the snow layer. This new algorithm will be the standard algorithm for Arctic sea ice concentration retrievals with the EOS Aqua advanced microwave scanning radiometer (AMSR-E) instrument. In this paper, we evaluate the performance of this algorithm for the summer period of 1996 using data from the special sensor microwave imager (SSM/I) which has frequencies similar to the AMSR instrument. The temporal evolution of summertime passive microwave sea ice signatures are investigated and sea ice concentration retrievals from the standard NASA team and the new algorithm are compared. The results show that the introduction of the additional sea ice type in the new algorithm leads to improved summertime sea ice concentrations. The SSM/I sea ice retrievals are validated using SAR-derived ice concentrations that have been convolved with the SSM/I antenna pattern to ensure an appropriate comparison. For the marginal ice zone, with ice concentrations ranging from 40% to 100%, the correlation coefficient of SAR and SSM/I retrievals is 0.66 with a bias of 5% toward higher SAR ice concentrations. For the central Arctic, where ice concentrations varied between 60% and 100%, the correlation coefficient is 0.87 with a negligible bias     

Analysis and simulation of reddish overshoot in active matrix organic light-emitting diode display with varying p-doped hole transport layer concentrations

A typical organic light-emitting diode (OLED) display has common organic layers between adjacent pixels, which ensure ease of manufacturing process and efficiency in operation. The p-doped hole transport layer (p-HTL) has low electrical resistivity, which results in a high efficiency OLED. However, the low resistivity results in various side effects, including color crosstalk and overshoot, mainly due to lateral leakage current flowing through this layer. Furthermore, virtual reality and augmented reality devices that require extremely high pixels per inch (PPI) and superior image quality are very sensitive to lateral leakage current. In this study, we propose a passive driving panel based on RGB top emission to efficiently measure and model the lateral leakage current characteristics according to the p-HTL concentration.In addition, we constructed a 1.5-inch active matrix organic light-emitting diode panel based on the n-type low-temperature polycrystalline silicon 4T2C pixel circuit. Subsequently, we quantitatively analyzed the reddish overshoot phenomenon during the black to white image transition. This effect was reduced at p-HTL concentrations under 1%.Finally, we analyzed the overshoot mechanism through SPICE simulations and realized the optimal lateral resistance value of the common organic layer for each PPI.     

基于硅压阻式传感器与光纤传感的静压桩贯入模型试验应用研究

将微型硅压阻式土压力传感器、孔隙水压力传感器及增敏微 型光纤光栅(fiber Bragg grating,FBG)应变传感器应用于静压桩贯入模型试验中,很好地测试了静 压桩贯入过程桩端 阻力、桩身轴力、桩土界面土压力和孔隙水压力。初步试验表明,微型硅压阻式土压力传感 器、孔隙水压 力传感器及增敏微型FBG应变传感器应用在静压模型桩贯入过程中,实现了贯入过程的桩端 阻力、桩身轴 力、桩土界面土压力和孔隙水压力的实时监测;桩身轴力和桩土界面有效侧向压力均随贯入 深度的增加而 增加,但同一深度处侧向压力逐渐减小。为静压桩贯入测试方法提供了参考依据,对进一步 研发室内试验微型传感器具有参考价值。     

Lateral diffusion effects in AuGe based source-drain contacts to AllnAs/InGaAs/InP doped channel MODFETs

We have investigated the formation of source-drain AuGe/Au and Ni/AuGe/Ni/Au alloyed ohmic contacts to AlInAs/InGaAs/InP doped channel MODFETs, and observed lateral diffusion of the contact system after the standard annealing procedure at the temperature range of 185 to 400°C. Auger depth profiling of contacts annealed at 250°C, revealed that Au(Ge) diffused through the top InGaAs and AlInAs layers into the active InGaAs layer, but had reduced penetration into the AlInAs buffer layer. This reduction in diffusion along the depth axis at the AlInAs buffer layer boundary is believed to result in enhanced lateral diffusion and the observed lateral encroachment of the contacts. Both Au and Ni containing contact systems showed similar behavior in terms of lateral diffusion with encroachment extending between 0.25 and 0.5 μm at the periphery of the contacts for annealing temperatures between 300 and 400°C. A controlled ramp-to-peak temperature annealing procedure is developed to suppress such lateral diffusion effects. Low temperature annealing (250°C) using this procedure resulted in equally low contact resistance values (∼0.1Θ-mm) and no lateral diffusion. It is concluded that in thin multilayered structures the modified annealing procedure presented here, is necessary for optimal ohmic contact formation.     

A complete electromagnetic simulation of the separated-aperturesensor for detecting buried land mines

The detection of buried land mines is a problem of military and humanitarian importance. Electromagnetic (EM) sensors (ground-penetrating radars) use signals at radio and microwave frequencies for this purpose. In the past, EM sensors for land-mine detection have been empirically developed and optimized. This has involved experimental tests that are complicated, time consuming, and expensive. An alternative is to carry out initial development and optimization using accurate numerical simulations. One objective of this paper is to show, for the first time, that such simulations can be done using the finite-difference time-domain (FDTD) method. The separated-aperture sensor has been under investigation by the United States Army for land-mine detection for many years. It consists of two parallel dipole antennas housed in corner reflectors that are separated by a metallic septum. It is a continuous-wave sensor tuned to a particular frequency (typically 790 MHz). When the sensor is over empty ground, the coupling between the antennas is very small. As the sensor is moved over a buried mine, the coupling between the antennas increases indicating the presence of the mine. In this paper, the complete EM system composed of the separated-aperture sensor, air and soil, and buried land mine is modeled using the FDTD method. The finite computational volume is truncated with an absorbing boundary condition: the generalized perfectly matched layer. Detailed studies made with the simulation increase the understanding of this sensor. Results computed from the simulation are in good agreement with experimental measurements     

Investigation of the Electromagnetic Interference Threat Posed by a Wireless Network Inside a Passenger Aircraft

Recent years have witnessed an incisive push to allow the use of wireless networks inside passenger aircraft. Research was recently conducted to investigate the internal electromagnetic (EM) environment excited by a wireless network inside a passenger aircraft to provide quantification of the ensuing EM interference threat. An airbus A319 EM model was developed and validated using experimental data and analytical techniques. The validated model was applied to the investigation of an 800 MHz cellular network. The peak electric field strength inside each of the A319 EM models examined was much less than the most severe RTCA/DO-160D radiated susceptibility test levels. The current coupled to a cable running along the length of the fuselage was much less than the minimum operating parameters of an extremely sensitive avionic system (e.g., strain sensor). The results obtained help to quantify and reinforce the conclusion of the major research efforts that the likelihood of interference with flight critical systems is low. The model presented herein can be easily adapted to study EM propagation for various types of wireless network and aircraft configurations, and the modeling approach employed could be of potential use in modeling other large, complex structures.     

电阻率对硅衬底微波传输特性影响分析

针对传统硅衬底介质损耗大的现象,通过软件电磁仿真手段分析不同电阻率硅衬底上微带线的传输特性,系统研究电阻率变化对硅衬底微波传输特性的影响,并与基于MEMS三维加工的低阻硅衬底进行比较。在30 GHz频率范围内,当硅衬底电阻率从10Ω·cm提升至4 000Ω·cm时,微带线插入损耗从20 dB/cm降低至0.6 dB/cm。电阻率大于100Ω·cm的高阻硅衬底微波传输特性优于带MEMS空腔的10Ω·cm低阻硅衬底。结果表明提升电阻率可有效降低硅衬底微波传输损耗,结合低成本成熟工艺等优点,高阻硅衬底具有广阔的微波集成应用前景。