An Asynchronous Implementation of Add-Compare-Select Processor for Communication Systems

A novel asynchronous ACS(add-compare-select) processor for Viterbi decoder is described.It is controlled by local handshake signals instead of the globe clock.The circuits of asynchronous adder unit,asynchronous comparator unit,and asynchronous selector unit are proposed.A full-custom design of asynchronous 4-bit ACS processor is fabricated in CSMC-HJ 0.6μm CMOS 2P2M mixed-mode process.At a supply voltage of 5V,when it operates at 20MHz,the power consumption is 75.5mW.The processor has no dynamic power consumption when it awaits an opportunity in sleep mode.The results of performance test of asynchronous 4-bit ACS processor show that the average case response time 19.18ns is only 82% of the worst-case response time 23.37ns.Compared with the synchronous 4-bit ACS processor in power consumption and performance by simulation,it reveals that the asynchronous ACS processor has some advantages than the synchronous one.

“中国好诗·第二季”首发

7月16日上午，“中国好诗·第二季”在京首发。郑玲的《让我背负你的忧郁》、马新朝的《响器》、商震的《半张脸》、娜夜的《个人简历》、邰筐的《徒步穿越半个城市》、轩辕轼轲的《挑滑车》、沈浩波的《向命要诗》、桑子的《栖真之地》、冯娜的《无数灯火选中的夜》和玉珍的《数星星的人》正式亮相，活动同时举办了各自代表作的读诗分享会。

刘庆邦:送你一片送你一片皎洁的月光

刘庆邦，著名作家。1951年12月生于河南沈丘农村。当过农民、矿工和记者。著有长篇小说（《断层》《远方诗意》《平原上的歌谣》《高高的河堤》等，中短篇小说集、散文集《走窑汉》《梅妞放羊》《遍地白花》《响器》等。短篇小说《鞋》获第二届鲁迅文学奖。中篇小说《神木》获第二届老舍文学奖。根据其小说《神木》改编的电影《盲井》获第53届柏林电影艺术节银熊奖。

Numerical Simulation and Analysis of Bipolar Junction Photogate Transistor for CMOS Image Sensor

A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue.

Testing an improved cymbal hydrophone

Cymbal hydrophones have small volume and high sensitivity, but their reception is not stable enough, and their reception is in too narrow a frequency band. In order to overcome these inadequacies, the structure of the cymbal hydrophone was improved. The single ceramic piezoelectric element was replaced with a double one, the radius of the ceramic piezoelectric element was reduced, and a parallel circuit was added. A static analysis of this new structure was developed, and then simulations were made of both the traditional and new hydrophone structure using finite element software. Tests were then conducted in a tank. The results showed that the improved hydrophone has reception in a wider frequency band, reception performance is stable within this frequency band, and sensitivity is still high.

Research on velocity and acceleration geophones and their acquired information

Based on the research of two geophone types （10 Hz moving-coil velocity and piezoelectric acceleration） and their velocity and acceleration parameters, frequency response functions have been determined, as well as the differences between them. Also, shock- vibration tests have been accomplished, not only to explain the two shock response signal differences, but also to analyze the response signal characteristics and its ability to carry information. In addition, seismic data acquisition experiments have been carried out under comparable conditions in the field. A contrast analysis of shot gathers and stack profiles acquired with the two geophone types is given in this paper. The results show that the acceleration signal from the acceleration geophone has a better advantage in terms of high signal-to-noise ratio, high accuracy, high resolution, and quantity of information to better meet current and future requirements for seismic exploration.

Device Robust-Design by Using Response Surface Methodology

Device robust-design is inherently a multiple-objective optimization problem.Using design of experiments (DoE) combined with response surface methodology (RSM) can satisfy the great incentive to reduce the number of technology CAD(TCAD) simulations that need to be performed.However,the errors of RSM models might be large enough to diminish the validity of the results for some nonlinear problems.To find the feasible design space,a new method with objectives-oriented design in generations that takes the errors of RSM model into account is presented.After the augment design of experiments in promising space according to the results of RSM model in current generation,the feasible space will be emerging as the model errors deceasing.The results on FIBMOS examples show that the methodology is efficient.

Characteristic of Intelligent Air Bag Venting Structure Actuating by Electrostrictive Stack Actuator

In this paper the conception of smart materials and structures is firstly combined with research of air bag,and the main theory of self adapting cushioning of intelligent air bag is expatiated.The intelligent venting structure is the main part affecting the cushioning result.Electrostrictive material was found having big force,high response speed and wide linearity,and it is fit to utilize in intelligent venting structure. The characteristic of the dynamic response and cushioning actuating of an electrostrictive stack actuator is analyzed,and the result of the computer simulation of the fuzzy control to intelligent venting structure is given.It is concluded that intelligent venting structure has good actuating characteristic and can satisfy the need of intelligent air bag.

Micro-process model of hydraulic shock absorber with abnormal structural noise

In order to discover the causes of the abnormal noise of shock absorbers, it is necessary to identify the operating characteristics of the shock absorbers. A micro-process model for operation of the hydraulic shock absorber was presented. A novel concept, which describes the process of hydraulic shock absorber by dividing it into smaller steps, was proposed. The dynamic model and the differential equations were established. The results of numerical simulation agree well with data obtained from the vibrostand test, indicating that the collision between the piston and the oil, the alternation of static friction and sliding friction acted between the piston and the cylinder, and the adherence between valve plate and piston result in impact on the piston head near the top dead center and the bottom dead center. Ultimately, the impact excites the high-frequency vibration of the piston structure, which can generate the abnormal noise in the hydraulic shock absorber after its transfer. And the maximum vibration acceleration on the piston head and the abnormal noise increase with the increase of the gap between the oil and piston rod head, the maximum static friction force and the adhering function, respectively.

Measurement of 3db Bandwidth of Laser Diode Chips

An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement by a new calibration method.In theory,the measuring range of the measurement system is only determined by the measuring range of the instruments network analyzer and photo detector.Diodes' bandwidth of 7 5GHz and 10GHz is measured.The results reveal that the method is feasible and comparing with other method,it is more precise and easier to use.

A Modified Split⁃Ring Resonator Antenna for Radio Frequency Identification Tag

A compact antenna formed by three concentric split rings for ultra-high frequency(UHF)radio frequency identification(RFID)tag is proposed in this paper.The antenna is composed of two parts,an outer short-circuited ring modified from a traditional split-ring resonator(SRR)antenna and an inner SRR load,so the antenna can be regarded as a short-circuited ring loaded with SRR.According to the transmission line theory,to conjugate match with the capacitive input-impedance of a tag chip,the length of the short-circuited ring isλg/4 shorter than that of an open-circuited dipole of a traditional SRR antenna,whereλg is the wavelengh of the operating frequency.Hence,the size of the proposed antenna is more compact than that of the traditional SRR antenna.Thereafter,the proposed antenna is simulated and optimized by ANSYS high-frequency structure simulator(HFSS).The impedance,efficiency,and mutual coupling of the fabricated antenna are tested in a reverberation chamber(RC).The results show that the size of the presented antenna is 83%smaller than that of the traditional SRR antenna and the proposed antenna can cover the whole UHF RFID operating frequency band worldwide(840—960 MHz).The measured read range of the tag exhibits maximum values of 45 cm in free space and 37 cm under dense tag environment.

Low-Rate DoS Attack Flows Filtering Based on Frequency Spectral Analysis

In frequency domain,the power spectrum of Low-rate denial of service(LDoS) attacks is totally spread into the spectrum of normal traffic.It is a challenging task to detect and filter LDoS attack flows from the normal traffic.Based on the analysis of LDoS attack flows and legitimate TCP traffic in time and frequency domains,the periodicity of the TCP traffic and LDoS attack flows is explored to facilitate the research of network traffic processing.Hence,an approach of LDoS attack flow filtering based on frequency spectrum analysis is proposed.In this approach,the TCP traffic and LDoS attack flows are transformed from the time domain into the frequency domain.Then the round-trip time(RTT) is estimated by using frequency domain search method.Analysis of amplitude spectrum shows that TCP traffic energy is mainly concentrated on the points of n/RTT.Therefore,a comb filter using infinite impulse response(IIR) filter is designed to filter out the LDoS attack flows in frequency domain,while most legitimate TCP traffic energy at the points of n/RTT are pass through.Experimental results show that the maximum pass rate for legitimate TCP traffic reaches 92.55%,while the maximum filtration rate of LDoS attack flows reaches 81.36%.The proposed approach can effectively filter the LDoS attack flows while less impact on the legitimate TCP traffic.

Fork-Join program response time on multiprocessors with exchangeable join

The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%.

Review on development progress of automatic manual transmissions control

In recent years, the sustainable development of automatic manual transmissions (AMTs) control in vehicles is conspicuous. The control applications have grown fast and steadily due to the tremendous progress in power electronics components and the control software that enhance the requirements for delivering higher vehicles performance. AMTs control strategies achieve a reduction in the driveline dynamic oscillations behavior during gear shifting and clutch starting up processes. AMTs future expectations are an increase of torque capacity, more speed ratios and the development of advanced and efficient electronic control systems. This paper concerns with the progressing view of AMTs in the past, today and future, gives an overview of the potential dynamic problems concerned with AMTs and some control strategies used to solve those problems.

Four optimal design approaches of high-order finite-impulse response filters based on neural network

Four optimal approaches of high-order finite-impulse response(FIR) digital filters were developed for designing four types filters using neural network algorithms. The solutions were presented as parallel algorithms to approximate the desired frequency response specification. Therefore, these methods avoid matrix inversion, and make a fast calculation of the filter’s coefficients possible. The convergence theorems of these proposed algorithms were presented and proved to illustrate them stable, and the implementation of these methods was described together with some design guidelines. The simulation results show that the ripples of the designed FIR filters are significantly little in the pass-band and stop-band, and the proposed algorithms are of fast convergence.

Numerical Simulation of Spectral Response for 650 nm Silicon Photodetector

The theoretical spectral response formula of the N+-N-I-P+ silicon photodetector with high/low emission junction is given. At the same time, considering the process requirements, the optimum structure parameters of silicon photodetector are obtained by numerical calculation and simulation. Under the condition of these optimum structure parameters, the responsivity of the silicon photodetector will be 0.48 A/W at 650 nm.

Box-like spectral response of a series-coupled microring resonant filter in a parallel channel

Formulas of the transfer functions are presented for a series-coupled microring resonant filter and the filtering characteristics of this device are investigated around the central wavelength of 1.55 μm.The simulation results show that when the number of the microring is 4,the amplitude coupling ratio between the channel and the microring is 0.25,that between two microrings is 0.022,and the flat box-like spectral response can be formed.The 3-dB bandwidth is about 0.2 nm,the insertion loss is about 1.5 dB,and the minimum of non-resonant light is close to -150 dB.

Solution of false alarm and slow response in flame detector

A new flame detector with one ultraviolet and two infrared detectors is designed. The ultraviolet detector is of rapid response(≤10 μs) while the two infrared detectors usually have a response time of more than 5 ms. The ultraviolet detector is applied to deal with the flame of large scales. When facing the flame of mid or small scales, the three detectors cooperate. Employing the high-order derivatives of the sample data of the infrared circuits to improve the sensitivity, the response speed is greatly improved. The data of the temperature sensor is used to adjust circuit parameters in real time, thus reducing the effect of temperature drift. The flame detectors are tested at different distances and the response time is as rapid as 0.65 ms. The test results show that the new flame detector has the characteristics of high speed and a low rate of false alarms.

Research on suppress vibration of rotor misalignment with shear viscous damper

A new type of shear viscous damper for rotating machinery is designed. The new damper with good stability and reliability can inhibit all kinds of frequency multiplication vibration caused by misalignment in the condition of nonstop machine. It analyzes and discusses the use of the shear viscous damper for misalignment vibration response inhibition with a finite element method, and experi ments are extensively carried out with a laboratory test rig. Both the simulation and experimental re suits basically agree well in that, the damper can effectively control the misalignment vibration of the rotor system and improves the stability of the plitude of one time running speed component bration has been basically eliminated. entire rotor system. Experimental results show the am decreases by 30% , and the two time running speed vibration has been basically eliminated.