发动机叶尖计时技术新突破

通过用传感器测定风扇叶片叶尖通过的时间间隔。可实现在飞行中实时监控叶片的状态。这是一种正在研发的新技术。

滇西泸水钨锡矿床^(40)Ar-^(39)Ar法成矿年龄研究

本文采用高精度的４０Ａｒ－３９Ａｒ计时技术，系统地测定了滇西泸水钨锡矿床片麻状花岗岩、锡矿石和钨矿石中的白云母和石英等矿物的年龄，结合野外地质情况和岩矿薄片镜下特征，查明该矿为多期成矿：片麻状花岗岩年龄为１６３Ｍａ，锡矿１４５Ｍａ，钨矿有两期，分别为６９Ｍａ和３９Ｍａ。同时研制了金属超高真空碎样提氩装置，并与ＭＭ－１２００质谱计系统连接，测定了钨矿石中石英的流体包裹体的４０Ａｒ－３９Ａｒ年龄，为矿床形成年龄测定开辟了新的实验测试途径。

活塞式体积管在检定质量流量计中的应用

作为容积式的流量标准装置,活塞式体积管在检定质量流量计时受操作难度、运行中产生的气泡和密度测量的方式等影响,在实际中应用较少。本文主要介绍了以水温测量密度和以双计时脉冲插值技术测量体积来检定质量流量计的新方法,并对日常应用中出现的问题进行了分析,提出了改进的方案。

A Reduced Complexity Time-Delay Tracking and Channel Estimation for OFDM Systems

This paper presented an improved channel estimator for orthogonal frequency division muhiplexing （OFDM） systems using joint time delay detection and channel gain estimation. The algorithm well designs an adjustment scheme using the time correlation of time delays to increase the accuracy of the time delay detection. The most attractive advantage is that the complicated matrix calculation is replaced by the search steps to estimate the channel parameters without significantly increasing the complexity of the system. The computer simulation demonstrates that the proposed algorithm can track the time delays adaptively and improve the channel estimation performance. Consequently, the better system performance will be achieved.

Kinetic studies on extra heavy crude oil upgrading using nanocatalysts by applying CFD techniques

Regarding the growth of global energy consumption and the paucity of light crude oil, extracting and using heavy and extra heavy crude oil has received much more attention, but the application of this kind of oil is complicated due to its very high molecular weight. High viscosity and low flowability complicate the transportation of heavy and extra heavy crude oil. Accordingly, it is essential to reduce the viscosity of heavy and extra heavy crude oil through in-situ operations or immediate actions after extraction to reduce costs. Numerical simulations are influential methods, because they reduce calculation time and costs. In this study, the cracking of extra heavy crude oil using computational fluid dynamics is simulated, and a unique kinetic model is proposed based on experimental procedures to predict the behavior of extra heavy crude oil cracking reaction. Moreover, the hydrodynamics and heat transfer of the system and influence of nanocatalysts and temperature on the upgrading of crude oil are studied. The geometry of a reactor is produced using commercial software, and some experiments are performed to examine the validity and accuracy of the numerical results. The findings reveal that there is a good agreement between the numerical and experimental results. Furthermore, to investigate the main factors affecting the process, sensitivity analysis is adopted. Results show that type of catalyst and concentration of catalyst are the parameters that influence the viscosity reduction of extra heavy crude oil the most. The findings further revealed that when using a 25 nm SiO_2 nanocatalyst, a maximum viscosity reduction of 98.67% is observed at 623 K. Also, a catalyst concentration of 2.28 wt% is best for upgrading extra heavy crude oil. The results obtained through sensitivity analysis, simulation model, and experiments represent effectual information for the design and development of high performance upgrading processes for energy applications.

A Fault Detection and Isolation Scheme Based on Parity Space Method for Discrete Time-delay System

A Fault detection and isolation(FDI)scheme for discrete time-delay system is proposed in this paper,which can not only detect but also isolate the faults.A time delay operator is introduced to resolve the problem brought by the time-delay system.The design and computation for the FDI system is carried by computer math tool Maple,which can easily deal with the symbolic computation.Residuals in the form of parity space can be deduced from the recursion of the system equations.Further more,a generalized residual set is created using the freedom of the parity space redundancy.Thus,both fault detection and fault isolation have been accomplished.The proposed method has been verified by a numerical example.

Time-domain training sequences design for MIMO OFDM channel estimation

This paper describes a Least Squares (LS) channel estimation scheme for MIMO OFDM systems based on time-domain training sequence. We first compute the minimum mean square error (MSE) of the LS channel estimation, and then derive the optimal criteria of the training sequence with respect to the minimum MSE. It is shown that optimal time-domain training sequence should satisfy two criteria. First, the autocorrelation of the sequence transmitted from the same antenna is an impulse function in a region longer than the channel maximum delay. Second, the cross-correlation between sequences transmitted from different antennas is zero in this region. Simulation results show that the estimator using optimal time-domain training sequences has better performance than that using optimal frequency training sequence at low signal-to-noise ratio (SNR). To reduce the training overhead, a suboptimal training sequence is also proposed. Comparing with optimal training sequence, it has low computation complexity and high transmission efficiency at the expense of little performance degradation.

Schedulability analysis for linear transactions under fixed priority hybrid scheduling

In hard real-time systems, schedulability analysis is not only one of the important means of guaranteeing the timelines of embedded software but also one of the fundamental theories of applying other new techniques, such as energy savings and fault tolerance. However, most of the existing schedulability analysis methods assume that schedulers use preemptive scheduling or non-preemptive scheduling. In this paper, we present a schedulability analysis method, i.e., the worst-case hybrid scheduling (WCHS) algorithm, which considers the influence of release jitters of transactions and extends schedulability analysis theory to timing analysis of linear transactions under fixed priority hybrid scheduling. To the best of our knowledge, this method is the first one on timing analysis of linear transactions under hybrid scheduling. An example is employed to demonstrate the use of this method. Experiments show that this method has lower computational complexity while keeping correctness, and that hybrid scheduling has little influence on the average worst-case response time (WCRT), but a negative impact on the schedulability of systems.

UML statechart based rigorous modeling of real-time system

Rigorous modeling could ensure correctness and could verify a reduced cost in embedded real-time system development for models. Software methods are needed for rigorous modeling of embedded real-time systems. PVS is a formal method with precise syntax and semantics defined. System modeled by PVS specification could be verified by tools. Combining the widely used UML with PVS, this paper provides a novel modeling and verification approach for embedded real-time systems. In this approach, we provide 1) a time-extended UML statechart for modeling dynamic behavior of an embedded real-time system; 2) an approach to capture timed automata based semantics from a timed statechart; and 3) an algorithm to generate a finite state model expressed in PVS specification for model checking. The benefits of our approach include flexibility and user friendliness in modeling, extendability in formalization and verification content, and better performance. Time constraints are modeled and verified and is a highlight of this paper.

Development of PC Worker’s Management System in PC Training Room and Office by Using IoT Technology

At present time, there has been a demand for management systems that can survey and monitor a PC （personal computer） practice room, movement of people in an office, situation of utilization of facilities and so on in real time without causing psychological stress. For example, PC administrators in Japanese national educational institutions must report operation status of PC practice rooms once a year. But, there is currently no system for automatically recording PC operating situations. Therefore, the burden on the PC administrators is big. In this study, we aimed at systems for accurately managing the sitting and work time without psychologically stressing PC users. This time, we propose uniform management systems of sitting and work time using smart tap node and mat sensor node by IoT （Internet of Things） technology. The smart tap was connected to PCs to acquire the operating status of the PCs. In parallel with this smart tap, the mat sensor was used to acquire human presence state. By calculating binary data representing the PC operating status and human presence state from the two sensing data （smart tap and mat sensor） by the proposed technique, we can exactly calculate wasteful power consumption etc. The use of IoT technology makes it unnecessary to use large installation services when introducing our system. Therefore, this our proposal system can be easily installed even by unskilled workers.

Study on Application of Virtual Reality Technique in Environmental Artistic Design

With the advent of the information age, people＇ s lives have been changed unknowingly owing to lots of modem technology means. For the environmental artistic design, the traditional mode of environmental artistic design is broken through after the emergence of computer technology and virtual reality technique, which makes the scheme and application of virtual reality technique in environmental artistic design to own more practical value. In this paper, the virtual reality technique and its practical application in environmental artistic design are set forth, and the profound influence on the actual design by the virtual reality technique is studied with expectation of enlightenment for broadening the thought of environmental artistic design.

GA-BASED MAXIMUM POWER DISSIPATION ESTIMATION OF VLSI SEQUENTIAL CIRCUITS OF ARBITRARY DELAY MODELS

In this paper, the glitching activity and process variations in the maximum power dissipation estimation of CMOS circuits are introduced. Given a circuit and the gate library, a new Genetic Algorithm (GA)-based technique is developed to determine the maximum power dissipation from a statistical point of view. The simulation on 1SCAS-89 benchmarks shows that the ratio of the maximum power dissipation with glitching activity over the maximum power under zero-delay model ranges from 1.18 to 4.02. Compared with the traditional Monte Carlo-based technique, the new approach presented in this paper is more effective.

A Parallel Finite Element Algorithm for Navier-Stokes Equations

The authors propose a numerical algorithm for the two-dimensional Navier-Stokes equations written in stream function-vorticity formulation. The total time derivative term is treated with a first order characteristics method. The space approximation is based on a piecewise continuous finite element method. The proposed algorithm is used to simulate the mechanical aeration process in lakes. Such process is used to combat the degradation of the water quality due to the eutrophication phenomena. For this application high computing facilities and capacities are required. In order to optimize the computing time and make possible the simulation of real applications, the authors propose a parallel implementation of the numerical algorithm. The parallelization technique is performed using the Message Passing Interface. The efficiency of the proposed numerical algorithm is illustrated by some numerical results.

An Objective-Based Gradient Method for Locating the Pareto Domain

In this paper, an objective-based gradient multi-objective optimization （MOO） technique, the Objective-Based Gradient Algorithm （OBGA）, is proposed with the goal of defining the Pareto domain more precisely and efficiently than current MOO techniques. The performance of the OBGA in locating the Pareto domain was evaluated in terms of precision, computation time and number of objective function calls, and compared to two current MOO algorithms： Dual Population Evolutionary Algorithm （DPEA） and Non-Dominated Sorting Genetic Algorithm I1 （NSGA-II）, using four test problems. For all test problems, the OBGA systematically produced a more precise Pareto domain than DPEA and NSGA-II. With the adequate selection of the OBGA parameters, computation time required for the OBGA can be lower than that required for DPEA and NSGA-II. Results clearly show that the OBGA is a very effective and efficient algorithm for locating the Pareto domain.

Enhancement of Voice Quality and Bit-rate Reduction by Prosodic Control in G.723.1 Vocoder

Speech coding techniques have been studied not truly to reduce the complexity and bit rate but also to improve the sound quality. CELP type vocoder, used as standard, supports the great stead quality even low bit rate. In this paper, the preprocessing of input speech to reduce the bit rate is different from the conventional vocoder. Different kinds of parameter are used for the preprocessing compared with the other parameters to t＇md the more appropriate parameter for the vocoder. The Parameters are used to synthesize the speech not to encode or decode for coding technique so we proposed the simple algorithm not to have the influence on the processing time or the computation time. The parameters in the preprocessing step are speaking rate, duration, and PSOLA technique.

On visual art elements of the web interface

With the rapid development of modern high-tech, human society is advancing towards the information age. The advent of Intemet technology has brought mankind a new communication experience, and it makes communication between people undergo a fimdamental change. Today＇ s information and communication has broken the traditional way, storage, use and exchange of information are all inseparable from the network, the platform. Network development is affecting all aspects of human behavior and production life. In network technology, web interface design is a very important part. Web interface design is inseparable from the visual arts, both in mutual integration and the overall design, so that the web interface has the aesthetic appeal of the visual arts and the humanities connotation. Due to the development of network technology, people also put forward higher requirements for web design. Web interface design should not only reflect the excellent content, but also create one of the most intuitive visual arts presentation form. This text will begin from a Web page design and production, analyzed and studied its visual art elements to achieve a reasonable and beautiful web interface.

Design and Fabrication of a Novel Core-Suspended Optic Fiber for Distributed Gas Sensor

We designed a novel core-suspended capillary fiber that the core was suspended in the air hole and close to the inner surface of the capillary, and experimentally demonstrated its fabrication technology. In addition, a method for linking a single mode fiber and a core-suspended fiber was proposed based on splicing and tapering at the fusion point between the two fibers. By combining with the optical time domain reflectometer technology, we constructed a distributed gas sensor system to monitor greenhouse gas based on this novel fiber.

Positioning reduction in the real-time phase of Chang'E-2 satellite

The precision of VLBI tracking delays and the positioning reduction results during the real-time tracking phase of the Chang'E-2 satellite are statistically analyzed.The application of the positioning reduction to the real-time monitoring of pivotal arcs of the Chang'E-2 satellite is discussed.The technical specifications of the tests of tracking and control systems in X-band are estimated and evaluated via the positioning reduction method.Useful methodology and software are prepared and practical experience in engineering and technology is accumulated for the follow-up lunar and deep space explorations of China.

Theoretical development for DSMC local time stepping technique

The direct simulation Monte Carlo(DSMC) method is the most mature and wildly used approach for nonequilibrium gas flow simulation.The phenomenological nature of this method brings flexibility to the computation algorithms.In this study,the theoretical foundations to decouple the molecular motion and collision within a time step are discussed in detail,which can be treated as criterions for the DSMC algorithms.Based on the theoretical developments,an improved local time stepping scheme is proposed,which specifies the movement time attribute and the collision time attribute for each representative particle.A free flow about a sphere body is considered as an example,which is compared with the calculations using the published local time stepping technique.The results show that the improved local time scheme is valid and is promising in realizing flow structures with strong variations.

A fast digital timing and analysis system based on real-time dCFD technique for nuclear physics experiments

In this paper a fast digital real-time spectrometer was developed for timing and analysis of nuclear pulse signals. The hardware system design and algorithm implementation with field-programming gate array （FPGA） and digital signal processor （DSP） were introduced. The performance of the digital constant fraction discrimination （dCFD） platform was experimentally tested with Agilent 80 MHz function/arbitrary waveform generator and LaC13：Ce3＋ scintillator detector for 22Na positron annihilation gamma spectroscopy. The amplitude and time information of ＂/photon was online obtained. The energy resolution could be 5.525% and the timing resolution 293.75 ps, the system error estimation of dCFD approach was also studied. The results showed that this spectrometer achieved a timing resolution close to that of traditional CFD timing resolution with a more sim- plified system structure.