“特可靠”在神经外科手术中的应用

“特可靠”在神经外科手术中的应用上海医科大学华山医院神经外科徐俊法，郭欢欢，周良辅从１９９４年１２月我们采用德国奈可明公司研制的“特可靠”（ＴＣＣ），用于神经外科手术１０５例，既可达到止血目的，又有修补硬膜缺损，或加固硬膜封闭缝合口，防止脑脊液漏的多...

基于比特可靠性的LDPC码编译码算法

提出了一种基于比特可靠性的低密度奇偶校验(LDPC)码编码算法和一种加权置信传播(BP)译码算法。该编码算法首先利用蒙特卡罗仿真得到LDPC码各个比特节点的出错概率,然后用已知信息替换易出错比特节点进行编码;该译码算法根据比特节点可靠性的差异,在译码时为每个比特节点赋予相应的权值,以调整它们对译码的影响程度。仿真表明,新的编译码算法使得系统性能大大提高,同时加快了译码迭代收敛速度。

特可靠

特可靠ＴａｃｈｏＣｏｍｂ【商品组成】每０．５ｃｍ厚，１ｃｍ２特可靠纤维网含马健胶原１．３～２．０ｍｇ。上面涂有：人体纤维蛋白原４．３～６．７ｍｇ，牛凝血酶１．５～２．６ＩＵ，牛抑肽酶０，０５５～０．０８７欧洲药典Ｕ，核黄素（作药面指示色）７～２６μｇ...

一种改进的短极化码球形译码算法

球形译码(Sphere Decoding,SD)能够有效地实现极化码最大似然译码的误码性能,文章提出基于比特翻转的多重球形译码树搜索(Multiple Sphere Decoding Tree Searches Based on Bit-Flipping,BF-MSDTS)算法进一步提升短极化码的性能,该算法通过扩大半径搜索和翻转不可靠比特提升误码性能,同时利用搜索终止准则和固定可靠比特降低复杂度,有效地解决了多重球形译码树搜索(Multiple Sphere Decoding Tree Searches,MSDTS)算法低信噪比下误码性能不如循环冗余校验(Cyclic Redundancy Check,CRC)辅助的串行消除列表(CRC Aided Successive Cancellation List,CA-SCL)算法的问题.仿真结果表明,在低信噪比时,当误码率为10-4时,与CA-SCL算法比较,提高了0.41dB,与MSDTS算法比较,提高了1.17dB.提出的BF-MSDTS算法的误码性能在较差的信道环境下优于现有的MSDTS算法以及CA-SCL算法.

一种低复杂度的多元LDPC译码算法

针对多元低密度奇偶校验(LDPC)码译码复杂度高、时延大等问题,提出了一种基于硬信息的低复杂度多元LDPC译码算法。来自信道的接收信号在初始化时,先进行非均匀量化预处理。在迭代过程中,校验节点端只需传输单个比特的二进制硬可靠度信息至变量节点。在变量节点端,可靠度信息按比特位进行简单的累加和更新,无需任何的系数修正操作。同时,变量节点使用了全信息的方式将信息传输至与其相邻的校验节点。仿真结果显示,与基于比特可靠度(BRB)的多元LDPC译码算法相比,提出的算法在较低量化比特情况下,能获得约0.3 d B的译码性能增益,且译码复杂度更低。

Monte Carlo numerical simulation and its application in probability analysis of long span bridges

To get the probability of long span bridges under the influence of external random factors, the Monte Carlo method using Latin hypercube sampling is applied. Combined with the condition assessment system on Runyang Suspension Bridge, which is the longest suspension bridge in China, the structural probabilities in normal and damaged situations are calculated with the external random factors considered including environmental temperature, wind load, load of vehicles, etc. The main assessment items contain the maximal vertical displacement of girder, the maximal stress of cables, the maximal horizontal displacement of towers etc. Finally, the probabilities and their cumulative distribution functions are provided. The analysis results can be plotted on line in a clear and vivid way, so the efficiency of assessment is increased and the decision-making of maintenance is more objective and accurate.

APPLICATION OF FUZZY LOGIC IN WEIGHTED INFORMATION FUSION OF HAND GEOMETRY AND PALM PRINTS

Based on the theory of fuzzy logic, the method of obfuscating coefficient and reliability to fuse the information of hand geometry and palm prints for identity discrimination is proposed. The experiment proves that the method is useful and effective. Its identification rate is up to 90%, which is 20%-30% higher than that of using hand geometry or palm prints singly,thus it can be widely used in highly demanded security field, such as finance, entrance guard, etc.

Analysis of Ground Motion Attenuation Characterization for Moderate Earthquakes in the Sichuan-Yunnan Region

The ground motion attenuation models for PGA,PGV and response spectrum at rock sites and soils sites are derived separately from the digital strong motion records of moderate earthquakes in the Sichuan-Yunnan region after 2007. By comparison with Yu Yanxiangs attenuation model for rock sites in western China,reliability of the model is verified for moderate earthquake. According to the distribution of strong motion data against magnitude and epicentral distance,the applicability and reliability of the results in this paper are discussed.

Discussion on dynamic reliability tolerance design technology of electromagnetic relay

Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can ensure that the products would work well under the influence of disturbing factors (including internal interference, external interference, and machining dispersion). Com- pared with static characteristic, dynamic characteristic of electromagnetic relay can describe its operating process better. This article researches influence of the three kinds of disturbing factors on the dynamic characteristic of electromagnetic relay based on calculating dynamic characteristic. Then, the dynamic reliability tolerance design method of electromagnetic relay is discussed considering three kinds of disturbing factors. Conclusions reached can help to assure the reliability of electromagnetic relay from the beginning of design.

Performance of Marine Power Plant Given Generator, Main and Distribution Switchboard Failures

Power generation is one of the most essential functions of any plant for continuous functioning without any interruption. A marine power plant （MPP） is the same section. In the present paper, the authors have tried to find the various reliability characteristics of an MPR A marine power plant which is a composition of two generators and in which one of them is located at the stern and another at the bow, both associated to the main switchboard （MSB）. The distribution switchboards （DSB） receive power from the MSB through cables and their respective junctions. Given that arrangement, a working based transition state diagram has been generated. With the help of the Markov process, a number of intro-differential equations are formed and solved by Laplace transform. Various reliability characteristics are calculated and discussed with the help of graphs.

The Effects of Stochastic Characteristics of Materials on the Reliability of a Composite Ship Hull

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.

MODELING AND SIMULATION OF COMPOUND CLUTTER FOR COASTAL ENVIRONMENT

This paper introduces a novel clutter power model of coastal compound and deduces the statistic characteristics and the arithmetics of model parameter estimation algorithm. Then, a novel coastal compound distributed model of the clutter amplitude is proposed and its statistic character- istics are studied. Subsequently, the nonlinear relation of autocorrelation function is deduced between the coastal compound clutter random sequences and the correlated Gaussian random sequences, which is the important prerequisite for the clutter simulation based on the ZMNL (Zero Memory NonLin- earity). Lastly, the advantage of the algorithm is demonstrated by a feasible simulation of the gen- eration of the random coastal compound clutter sequences.

Reliability analysis of supporting pressure in tunnels based on three-dimensional failure mechanism

Based on nonlinear failure criterion,a three-dimensional failure mechanism of the possible collapse of deep tunnel is presented with limit analysis theory.Support pressure is taken into consideration in the virtual work equation performed under the upper bound theorem.It is necessary to point out that the properties of surrounding rock mass plays a vital role in the shape of collapsing rock mass.The first order reliability method and Monte Carlo simulation method are then employed to analyze the stability of presented mechanism.Different rock parameters are considered random variables to value the corresponding reliability index with an increasing applied support pressure.The reliability indexes calculated by two methods are in good agreement.Sensitivity analysis was performed and the influence of coefficient variation of rock parameters was discussed.It is shown that the tensile strength plays a much more important role in reliability index than dimensionless parameter,and that small changes occurring in the coefficient of variation would make great influence of reliability index.Thus,significant attention should be paid to the properties of surrounding rock mass and the applied support pressure to maintain the stability of tunnel can be determined for a given reliability index.

Dynamic Reliability Evaluation of Double-Layer Cylindrical Latticed Shell under Multi-Support Excitations

To overcome the excessive computational cost and/or bad accuracy of traditional approaches,the probabilistic density evolution method(PDEM) is introduced.The dynamic reliability of a double-layer cylindrical latticed shell is evaluated by applying PDEM and Monte Carlo Method(MCM) respectively,and four apparent wave velocities(100 m/s,500 m/s,800 m/s and 1 200 m/s) and five thresholds(0.1 m,0.2 m,0.3 m,0.4 m and 0.5 m) are taken into consideration.Only the difference between threshold and maximal deformation...

Proposed Simplified Procedure for Safety Factor Scaling for Various Life Cycles

It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important infrastructure facilities, important religious structures or in case of extended returning period of seismic event or floods. Beside issues of durability and maintenance aspects, this involves also the need to cover the probability of exceeding characteristic design live loads during the extended period, while keeping the same levels of the accepted risk that were assumed by the various codes, as good enough for the standard 50 year life cycle. Bearing in mind that design procedures, formulations, materials characteristic strengths and partial safety factors are used for these structures as per the existing codes, scaling of partial safety factors, or alternatively an additional ＂compensating＂ factor is required. A simplified approach and procedure to arrive at a reasonable calibration of the code safety factors based on 50 years to compensate for an extended life cycle, based upon structural reliability considerations, is proposed.

Service-Oriented Middleware for Heterogeneous Environment in Intemet of Things

A great number of sensor technologies are applied in the Intemet of Things （loT） currently and more are emerging, which rmkes the loT a heterogeneous network. This paper discusses the convergence and integration problem in IoT. A Service-Oriented Middleware for Heterogeneous Environment （SOMHE） in IoT is proposed. The purpose of the middleware is to shield the differ- ence between protocols in the sensor layers such as Radio Frequency Identification （RFID） and Zig-Bee by defining the data conversion and mapping model. A Web service interface is supplied by this middleware, thus the complexity of high level appli-cation development can be reduced greatly. The feasibility and reliability of this middleware is veri-fied by a demonstration systelTL

Study on slope reliability method Response Surface Method based on Morgenstern-Price Method

The combination of Morgenstern-Price Method （MPM） with Response Surface Method （RSM） improves the eonventional RSM by replacing Finite-Element Method （FEM） with MPM, which is a type of reliability analysis method-RSM based on MPM, and makes the computing process simpler. The stability of the slope was re-evaluated by use of Monte Carlo method （MCM） and the result contrasted with the fore is the conclusion. The reliability analysis of the artificial slope in Donggang Power Station was carried on, and obtained the reliable charaeteristics, which provided basis for the project.

Reduced Expanding Load Method for Simulation-Based Structural System Reliability Analysis

The current situation and difficulties of the structural system reliability analysis are mentioned. Then on the basis of Monte Carlo method and computer simulation, a new analysis method reduced expanding load method (RELM) is presented, which can be used to solve structural reliability problems effectively and conveniently. In this method, the uncertainties of loads, structural material properties and dimensions can be fully considered. If the statistic parameters of stochastic variables are known, by using this method, the probability of failure can be estimated rather accurately. In contrast with traditional approaches,RELM method gives a much better understanding of structural failure frequency and its reliability index β is more meaningful.To illustrate this new idea, a specific example is given.

A robust object tracking framework based on a reliable point assignment algorithm

Visual tracking, which has been widely used in many vision fields, has been one of the most active research topics in computer vision in recent years. However, there are still challenges in visual tracking, such as illumination change, object occlu- sion, and appearance deformation. To overcome these difficulties, a reliable point assignment （RPA） algorithm based on wavelet transform is proposed. The reliable points are obtained by searching the location that holds local maximal wavelet coefficients. Since the local maximal wavelet coefficients indicate high variation in the image, the reliable points are robust against image noise, illumination change, and appearance deformation. Moreover, a Kalman filter is applied to the detection step to speed up the detection processing and reduce false detection. Finally, the proposed RPA is integrated into the tracking-learning-detection （TLD） framework with the Kalman filter, which not only improves the tracking precision, but also reduces the false detections. Experimental results showed that the new framework outperforms TLD and kernelized correlation filters with respect to precision, f-measure, and average overlap in percent.

筛检:太多?还是太少?

基于“预防胜于治疗”和“预防比治疗便宜”的理念,预防医学是家庭(全科)医生工作重要的一环,筛检成为普遍的工作。但我们要清楚筛检的目的和作用,怎样去评价它们的利与弊?不可以盲目地接受一切。在此我将阐述一些基本概念。 我将论证的是:太多——是指对某些筛检工作的效能、