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To address the characteristics of traditional obfuscation methods such as single approach and obvious features, a Parent-based Powershell Script Fusion Technology is proposed based on code fusion. This technology uses the target script to undergo slice encryption processing, and in-depth fusion with the parent script in the execution logic and execution flow, and uses the parent script to conceal the behavior characteristics of the target script. A number of Powershell scripts commonly used for infiltration are selected as the test set to test the proposed technique. The test results show that the proposed technique can reduce the detection rate of the antivirus engine for the target script and has a greater advantage in anti-static analysis.

In recent years, PowerShell scripts can be easily obfuscated and widely used due to its usability and flexibility. However, anti-obfuscation tools such as PowerShellProfiler and CyberChef also developed rapidly. In order to improve the security of scripts, this paper proposes a PowerShell obfuscation technology based on abstract syntax tree transformation. Firstly, this technology performs the equivalent replacement of the grammatical structure in the script. In addition, it also changes the sequence of the child nodes of the abstract syntax tree. Finally,it obfuscates the PSToken in the script. Thus, this technology can make up for the defects of the traditional obfuscation technology, and hide the program logic better to improve the concealment of the script. The experimental results show that the use of this technology proposed in this paper can improve the strength of obfuscation over 82.7% on average, which is 16% higher than traditional obfuscation technology. Moreover, this method is more effective against anti-obfuscation tools.

The correct handling and guidance of the public opinion of the earthquake network in the new situation is related to the social image of the earthquake department and is an important indicator for testing the modernization of social governance capabilities for earthquake prevention and mitigation. On the basis of summarizing and analyzing the experience and lessons of multiple earthquake public opinion cases, this paper systematically summarizes the social governance dilemma faced by the earthquake public opinion, introduces public opinion index for quantitative analysis, puts forward new countermeasures and suggestions to do a good job in seismic network public opinion scientific guidance under the new situation.This is of great significance to further improve the effectiveness of earthquake public opinion guidance and response capabilities.

A fast statistical estimation algorithm with vector quantification algorithm is proposed for data compression in digitized radio-over-fiber system. The original signal vector is firstly constructed by two neighboring samples of analog signals. After the companding transformation, the original signal vector with two-dimensional Gaussian distributions is transformed into the signal with two-dimensional uniform distributions. Then, the quantization processing is simplified into two dimensional uniformly quantization. Compared with the traditional fast statistical estimation algorithm and Lloyd algorithm, for a digitalized radio over fiber system with 64Gbit/s radio signal, performance of error vector magnitude in fast statistical estimation algorithm with vector quantification algorithm can be improved by 25%.

we propose an all-optical scheme for ultra-bright γ-ray emission and dense positron production with lasers at intensity of 1022-23 Wcm-2. By irradiating two colliding elliptically-polarized lasers onto two diamondlike carbon foils, electrons in the focal region of one foil are rapidly accelerated by the laser radiation pressure and interact with the other intense laser pulse which penetrates through the second foil due to relativistically induced foil transparency. This symmetric configuration enables efficient γ-photon emission with unprecedented brightness of 1025 photons/s/mm2/mrad2/0.1%BW at 15 MeV and intensity of 5×1023 Wcm-2. A GeV positron beam with density of 2.5×1022 cm-3 and flux of 1.6×1010/shot is achieved.

An all-optical scheme for generation and acceleration of relativistic electron sheets is proposed. When an intense Laguerre-Gaussian (LG) laser pulse sweeps microdroplets, annular sub-femtosecond electron bunches with one laser wavelength spacing are dragged out by the radial component of laser electric fields, and then efficiently accelerated by the longitudinal electric fields. Once fleeing from the droplet, these bunches are squeezed into dense sheets and trapped by the potential well of the transverse ponderomotive force, which can stably propagate for several hundred femtoseconds and are potential for applications in short x/γ-ray radiation sources.

Time and wavelength-division multiplexed passive optical network (TWDM-PON) is a primary solution for the next-generation passive optical network. Previous works in TWDM-PON mainly adopt dual energy-saving modes in ONUs for serving downstream traffic. Such approach may lead to significant energy waste. This paper proposes a cycle-based tri-mode energy-saving mechanism by jointly considering both packet arrival time and tuning time, to achieve enhanced energy saving and delay performance. Simulation results show that proposed scheme saves the energy on both ONU and OSU while providing satisfactory QoS performance.

How to calculate the reference voltage vector is an important issue in space vector modulation direct torque control (SVM-DTC) of permanent magnet synchronous motor (PMSM). The effect of zero vector on electromagnetic torque during all speed range is analyzed on the basis of the relation between voltage vector and torque current component. And the analysis shows that in conventional DTC system of PMSM available voltage vector is only six which is the mainly cause of high ripple of torque. A robust SVM- DTC method of PMSM is designed in which the reference voltage vector is calculated with the flux position, error of torque and flux. The method is simple to implement and insensitive to motor parameters error. First order filter cascaded with high pass filter (HPF) is adopted to estimate stator flux accurately. The experimental results are carried out and show that the improved SVM-DTC has the advantage of simplicity, robustness and improved performance.

Due to lighter, stiffer and offer superior heat-sinking than traditional packaging materials, Si-Al alloys have been proved as novel materials used for packaging microwave hybrid circuitry. In the current paper, finite element geometric models based on the real microstructural images of 40Si-Al are generated. Furthermore, based on Fourier's law for heat conduction and thermal expansion equation, thermal properties including the thermal conductivity and the coefficient of thermal expansion (CTE) of 40Si-Al are quantified by finite element method (FEM). By means of statistical method in conjunction with FEM results, the thermal conductivity and CTE at room temperature are calculated, respectively. The numerical simulation result agrees with the corresponding experimental result, which shows that the methodology developed in this paper is efficient in calculating thermal properties of Si-Al alloys.

In the future sustainable energy system, the recyclable and none-environmental pollution hydrogen-based energy is widely approved in all fields in the future. However, the severe clag, in the development process of industrialization and generalization of hydrogen-based energy, which is lack of the satisfied hydrogen storage material. Over the last decade, material-workers have had a series of researches on the preparation of solid-state hydrogen storage materials and relative hydrogen storage possibilities. The researches mainly includes the following types: (i) Steady large surface areas, such as carbon structures hydrogen storage material; (ii) All kinds of mental and different types of mental alloys, such as the hydrogen storage material based on the element Mg; (iii) All kinds of organic hydrogen storage materials, etc. This paper mainly presents the above mentioned two types of hydrogen storage materials and introduces the aspects of hydrogen storage property and mechanism, mechanical strength of material, porosity and affinity to hydrogen.

According to the computer is more and more powerful; the computer animation is widely applied in the game, entertainment, and scientific fields. When making a computer graphics (CG) animation, firstly we build three-dimensional models, and then attach the motion sequences on these models. Either key-frame setup or motions capture systems can help to get the motion data, and both of they need considerable work. Thus, the motion data cost expensive, and need the copyright protection. In this paper, we'll develop the digital watermarking technology for the motion capture (MOCAP) data. When watermarking some characteristics of the MOCAP data such as the physical feature of an articulated link model should be maintained. The requirement of imperceptibility in watermarking motion data is higher than in other watermarking applications such as images or video. For considering both the time varying and joints relations in motion, we adopted the singular value decomposition to resolve the multiple variables problem. In simulation results, some signal processing of motion data has been used to verify the robustness.

Retention properties of written nanodots for Pb(Zr0.2Ti0.8)O3 have been investigated. The imaging voltage plays an important role when investigating small unstable domains. Even with an imaging voltage far below the coercive voltage the boundaries of the domains are switched during imaging by what the measured nanodomain stability is strongly influenced

The increasingly popular sub-threshold design is strongly calling for EDA support to estimate noise margins, minimum functional supply voltage, as well as the functional yield. In this paper, we propose a fast, accurate and statistical approach to accomplish these goals. First, we derive close-form functions based on a new equivalent resistance model which enables the fast estimation of noise margins of individual cells at the gate-level. Second, we propose to calculate and propagate the noise margin information with an affine arithmetic model that takes into account process variations and correspondent inter-cell correlations. Experiments with ISCAS benchmarks have shown that the new approach has an accuracy of 98.5% w.r.t. transistor-level Monte Carlo simulations. The running time per input vector of the new approach only needs a few seconds, in contrast to the many hours required by transistor-level DC Monte-Carlo simulations. To the best of our knowledge, we are the first to provide a fast, accurate and statistical methodology other than Monte-Carlo simulation for the noise margin estimation of sub-threshold combinational circuits

For several kinds of advanced applications, such as RFID, telecommunication, portable electronics, or wearable electronics, the need of packaged semiconductor chip thick is getting thinner drastically. One representative technology is to embed an active device into an organic substrate by sequential build-up processes, for example, chip-in-polymer by IZM, chip-scale-module by Fujitsu, bumpless build-up layer by Intel, and chip-in-substrate package by ERSO/ITRI. However, reliability of an ultra-thin chip is decayed dramatically as the decay of chip thickness. This negative result of chip strength reduces the reliability of a semiconductor packages. In this paper, we want to get the optimal processes through the studies on wafer thinning and singulating respectively. As the aforementioned description, we did the sequential experiments on thinning and singulating to find out the optimal processing flow. In the wafer thinning study, the average chip strength of plasma dry etching is enhanced 40 to 50 percentages than standard backside grinding. Because DBG is a good solution for ultra-thin wafer processing, the effect on chip strength is also important in the study for the industry. It is enhanced about 10 percentages. On the other hand, the average chip strength of laser cutting is much lower than standard die dicing. Through the comparison of OM pictures of traditional dicing, DBG, and laser cutting, the chipping situations are observed clearly. DBG plus plasma etching does minimize the chipping to provide a more reliable chip. The study on wafer thinning and singulating processes is evaluated successfully in this paper. There are several methods generated and proved to enhance the strength of an ultra-thin chip. According to the results of the research, the novel, innovative, and leading-edge packaging technology can be realized via the more reliable ultra-thin chips.

The structure of chip-in-substrate package, CiSP, is shown. The thin chips (50mum) are bonded on the organic substrate (BT) flatly. Subsequently, the chips are covered among the build-up dielectric layer, which can be either a RCC (resin coated copper) material or an organic dielectric material (ABF) by a lamination process. Via holes on the chip's I/O pad and substrate are drilled by laser. The interconnection between chip and substrate is created by Cu without bump. The main issue is focused on the interfaces among different materials. This shorter interconnection can match the demand for fast electrical response application. At the same time, the stresses simulation for the interfaces or each key location in a CiSP is also investigated to optimize the manufacturing processes

Due to environmental concerns, the need for lead-free solutions in electronic components and systems is receiving increasing attention within the semiconductor and electronics industries. Sn-Ag-Cu systems are some of the more promising materials to replace the eutectic Sn-Pb solder. In this paper, a chip scale package assembled on board test and a notebook motherboard surface mount assembly were used to investigate the characteristics of Sn-3.0 Ag-0.5 Cu solder alloy from three different companies. One eutectic tin-lead solder was included for comparison. For the chip scale package, the PCB's surface finish included OSP (organic solderability preservatives) and electroless Ni/immersion Au. OSP and immersion Ag PCB surface finish was used in the notebook motherboard surface mount assembly. In-circuit test and function test were used to evaluate the properties. Thermal cycling test was used to evaluate the reliability of the solder joints. Failure modes of Sn-Ag-Cu solder and Sn-Pb solder alloys were also investigated. Scanning electron microscope (SEM) and optical microscope (OM) were utilized to observe the fracture morphology; energy dispersive spectrometer (EDS) was employed to analyze the distribution of the elements and the intermetallic compounds (IMCs) formed at the interface. All the chip scale package samples passed the electrical test after 2500 thermal cycles. All Sn-Pb and Sn-Ag-Cu solder joints of CSP possess good board-level reliability. But the TCT results of notebook motherboard assembled by Sn-Ag-Cu were not so good. About one half of samples didn't pass the function test after 500 thermal cycles. By failure analyses, we found some cracks in the joints and all the failed components were made by ceramic-based chip.