Performance Analysis of RFID Framed Slotted Aloha Anti-Collision Protocol

In this paper, we develop a novel mathematical model to estimate the probability distribution function of the number of tags discovered after a certain number of interrogation rounds. In addition, the pdfs of the number of rounds needed to discover all the tags are also calculated. The estimation of such pdfs will be helpful in estimating the number of interrogation rounds and the optimal parameter configuration of the RFID system which in turn will be helpful in estimating the time needed to discover all tags. Our results show that the proposed model accurately predicts the tags detection probability. We then use the proposed model to optimally configure the reader parameters (i.e. the frame size and the number of interrogation rounds).

Distance-Measuring Technology Using LD for Auto Anti-Collision

Auto anti-collision technology is one of the main research subjects of automobiles’ safety technology. Aiming at the key technology of Auto anti-collision, measuring the distance from obstacles, based on the theory of phase laser distance ranging, Laser Diode (LD) distance-measuring system for auto anti-collision has been developed to solve the problem of on-line measuring distance technology in middle to long distance utilizing the good characteristics of LD when modulating its optical intensity and adopting typical kinds of filter techniques in this paper. By theoretical analysis, adopting typical kinds of filter techniques can reduce the interference of strong light, so distance-measuring range can be 0.5–100 m in daytime or 1–200 m at night. And more, from theoretical analysis and experiment result, it can guarantee the high measuring resolution which can be less than 24.5 mm, utilizing the method of two Laser Diode optical intensity modulating wavelength and complimenting precise calibration and revision. The idea of LD distance-measuring technology is novel and feasible and this technology can be applied in Auto anti-collision. Key words laser diode - phase laser distance ranging - filter techniques - auto anti-collision CLC number TH 161 Foundation item: Supported by the National Natural Science Foundation of China (59675080, 59805006) and Wuhan Chenguang Foundation (20025001001)Biography: Zhang Xin-bao (1965-), male, Associate professor, research direction: precise mechanism and instrument.

Ultra-low power anti-crosstalk collision avoidance light detection and ranging using chaotic pulse position modulation approach

A novel concept of collision avoidance single-photon light detection and ranging（LIDAR） for vehicles has been demonstrated, in which chaotic pulse position modulation is applied on the transmitted laser pulses for robust anti-crosstalk purposes. Besides, single-photon detectors（SPD） and time correlated single photon counting techniques are adapted, to sense the ultra-low power used for the consideration of compact structure and eye safety. Parameters including pulse rate, discrimination threshold, and number of accumulated pulses have been thoroughly analyzed based on the detection requirements, resulting in specified receiver operating characteristics curves. Both simulation and indoor experiments were performed to verify the excellent anti-crosstalk capability of the presented collision avoidance LIDAR despite ultra-low transmitting power.

Geochemistry and Sr,Nd Istopes of Granitoids from the Lac Ifni Area(Sirwa Massif-Anti-Atlas Morocco):A Geodynamic Setting for the Post-collisional Ediacaran Magmatic Chain of the Anti-Atlas

The plutonic rocks of the westernmost part of the Sirwa massif belong to the Ediacaran post-collisional magmatic chain of the Anti-Atlas.The geochemistry of major and trace elements attests that the fractional crystallization cannot account for the variations between the granitoids and the associated MME.They represent two contemporaneous but independent magmatic tendencies.However,Sr and Nd configur data argue for a similar and juvenile material

Novel Tag Anti-Collision Algorithm with Adaptive Grouping

For RFID tags, a Novel Tag Anti-collision Algorithm with Grouping (TAAG) is proposed. It divides tags into groups and adopts a deterministic method to identify tags within group. TAAG estimates the total number of tags in systems from group identifying result and then adjusts the grouping method accordingly. The performance of the proposed TAAG algorithm is compared with the conventional tag anti-collision algorithms by simulation experiments. According to both the analysis and simulation result, the proposed algorithm shows better performance in terms of throughput, total slots used to identify and total cycles.

Application of Ship Maneuvering Simulator's Technology on Research of Vessels Automatic Anti-Collision

In this paper, the authors make a summary of current situation of research on the Auto Anti-Collision, briefly introduce the components and functions of the NSACA Simulation Platform and bring forward the project to realize the simulation of an Automatic Anti-Collision control, based on the NSACA Simulation Platform. Finally give typical examples from a great deal of simulating tests and analyze them.

Synchronous Dynamic Adjusting: An Anti-Collision Algorithm for an RF-UCard System

An RF-UCard system is a contactless smartcard system with multiple chip operating systems and multiple applications. A multi-card collision occurs when more than one card within the reader’s read field and thus lowers the efficiency of the system. This paper presents a novel and enhanced algorithm to solve the multi-card collision problems in an RF-UCard system. The algorithm was originally inspired from framed ALOHA-based anti-collision algorithms applied in RFID systems. To maximize the system efficiency, a synchronous dynamic adjusting (SDA) scheme that adjusts both the frame size in the reader and the response probability in cards is developed and evaluated. Based on some mathematical results derived from the Poisson process and the occupancy problem, the algorithm takes the estimated card quantity and the new arriving cards in the current read cycle into consideration to adjust the frame size for the next read cycle. Also it changes the card response probability according to the request commands sent from the reader. Simulation results show that SDA outperforms other ALOHA-based anti-collision algorithms applied in RFID systems.

Simulation Analysis on Navigation Indexes of Wanzhou Yangtze River Highway Bridge after the Anti-Collision Device Construction by Ship Model Test

After the anti-collision facility construction of Wanzhou Yangtze River Highway Bridge, the conditions of navigation in bridge area are complex. In order to study the navigation conditions of the reach and layout optimization measures, ensuring the safety of the ship navigation test has been carried out on the ship model navigation in the bridge area. According to the requirements of the maximum safety limit of the ship model test, the paper puts forward the best route, the control method and the difficulty of navigation through the analysis of the test results, and finally gives the recommendations and suggestions.

大跨梁-拱组合刚构桥船撞力和抗撞性能研究

梁-拱组合刚构桥是一种新桥型,船撞研究较少。该文以礼嘉嘉陵江大桥为工程背景,研究大跨度上承式梁-拱组合刚构桥梁的船撞力标准值和抗撞性能。首先确立了代表船型和船撞计算工况,利用ANSYS/LS-DYNA非线性有限元瞬态动力软件模拟了单墩模型在各工况下船桥碰撞过程,并对比了船撞力有限元仿真结果与多种经验公式计算结果。最后利用全桥模型和验算截面的极限承载力反推得到桥墩的极限抗船撞力,对桥墩的抗撞性能进行了评估。结果表明:船撞力具有很强的非线性波动特征,船艏最大撞深发生时刻滞后于最大撞击力发生时刻,船桥碰撞过程中的系统能量主要是由船舶动能转化为船艏局部变形内能;不同的船撞力经验公式的计算结果相差较大,推荐采用动力仿真模拟值;极限抗船撞力验算结果表明礼嘉嘉陵江大桥主墩的抗撞性能满足要求。

FRP-混凝土组合式护栏防护重型车辆撞击的能力

为提高低等级混凝土护栏防护重型车辆的能力,设计了3种不同构造形式的复合材料护板,分别设置在混凝土护栏表面形成组合式护栏。建立车-护栏精细化有限元模型,通过与实车碰撞试验结果对比,验证了有限元模型的可靠性。考虑撞击力、碰撞角度、车辆轨迹、货厢尾部抬高、车辆动态外倾值、车辆外倾角6个评价指标,对比分析了3种方案护栏的防车撞性能。结果表明,在整体式货车撞击下,3种方案护栏均能顺利引导车辆转向,不带阻坎的方案一的各主要指标均优于其他方案,防护能力最优;在拖挂式货车撞击下,方案一的护栏导向与阻挡性能依然良好,驶出角仅为0.75°;改造后的组合式护栏防护能量达到650 kJ,防护能力是改造前的4倍。

升船机钢丝绳-缓冲油缸防撞装置设计方法

钢丝绳-缓冲油缸防撞装置主要应用于过船规模较大的升船机工程中,目前关于该形式防撞装置设计方法的研究甚少,且存在一定局限性,直接影响防撞装置的布置和设计。基于船舶与防撞装置撞击过程中能量转换以及空间几何关系的分析,提出钢丝绳-缓冲油缸防撞装置设计计算方法,包括钢丝绳张力、船舶水平行进距离和油缸缓冲行程等重要参数的设计计算和控制条件的确定。通过设计计算结果与向家坝升船机钢丝绳-缓冲油缸防撞装置实船试验结果的比较,验证了本设计方法的安全性和合理性。提出的设计方法可为升船机钢丝绳-缓冲油缸防撞装置的设计和改造提供参考。

基于3,5-二溴水杨醛席夫碱镍配合物-氧化石墨烯电化学免疫传感器检测Anti-IgG含量的研究

应用物理吸附法将羊抗人IgG抗原直接固定于3,5-二溴水杨醛席夫碱镍配合物-氧化石墨烯修饰的金电极表面,制备电化学免疫传感器。采用循环伏安法和交流阻抗法对传感器进行表征,结果表明该传感器适合检测Anti-IgG浓度。同时探讨了缓冲液pH值、扫描速度、免疫反应温度、抗原与抗体配比对循环伏安峰电流的影响,结果表明在5-100mV/s扫速范围内,峰电流与扫速呈线性。孵育最优条件为25℃,h-IgG与Anti-IgG配比为1∶1。循环伏安法研究还表明Anti-IgG浓度在0.01-260μg/L范围内,线性关系良好,相关系数r^2=0.993,检出限（S/N=3）为0.006μg/L,据此建立了检测Anti-IgG浓度的新方法。

信号分子IRAK1/4在antiβ-2GPI/β2GPI复合物诱导THP-1细胞表达TF中的作用探讨

目的:探讨IRAK1和IRAK4在antiβ-2GPI/β2GPI复合物诱导单核细胞株THP-1表达组织因子(TF)中的作用。方法:利用荧光定量PCR(Real-time PCR)、TF活性试剂盒分别检测THP-1细胞表达TF mRNA及TF活性;Western blot检测anti-β2GPI/β2GPI复合物诱导THP-1细胞表达IRAK1、磷酸化-IRAK1(p-IRAK1)、IRAK4情况;观察IRAK1/4抑制物是否干预anti-β2GPI/β2GPI复合物诱导THP-1表达TF。结果:Antiβ-2GPI/β2GPI复合物(100μg/ml)诱导THP-1细胞表达TF显著增加(P<0.05 vs control);Antiβ-2GPI/β2GPI复合物(100μg/ml)刺激THP-1细胞表达IRAK1、p-IRAK1、IRAK4(蛋白)显著升高(P<0.05 vscontrol);IRAK1/4抑制物(50μmol/L)能够阻断antiβ-2GPI/β2GPI复合物(100μg/ml)诱导THP-1表达TF及IRAK1磷酸化的效应。结论:antiβ-2GPI/β2GPI复合物诱导THP-1细胞表达TF过程中,信号分子IRAK1/4被激活进而发挥重要作用。

三维Anti de Sitter空间中Lorentzian曲面的S_t^1×S_s^1-值光锥Gauss映射的奇点分类

利用Arnol'd的Legendrian理论,对三维Anti de Sitter空间中Lorentzian曲面进行了研究.引入光维高度函数概念研究了三维Anti de Sitter空间Lorentzian曲面的S1t×S1s-值、光锥Gauss映射的奇点,进行了奇点分类,揭示了类光Causs-kronecker曲率之间的关系;并研究了Lorentzian曲面的一些基本几何性质.

钢-UHPC组合式防撞浮箱防撞性能研究

由于钢-橡胶组合式防撞浮箱被小型船舶撞击后防腐涂层易被破坏,引起箱体进水、防撞装置下沉等问题,因此多采用新型的钢-UHPC组合式防撞浮箱。为了解钢-UHPC组合式防撞浮箱防撞性能,采用数值模拟的方法,从船舶撞击速度以及角度2个方面探究钢-UHPC组合式防撞浮箱对削减桥墩受到撞击力的影响。结果表明:1)钢-UHPC组合式防撞装置具有良好的削减撞击力的能力,大约在30%~40%;2)该防撞装置对撞击力的削减在正撞下随速度增加而增强,在20°斜撞下随速度增加而减弱,但都能达到30%以上;3)大角度撞击下防撞装置对撞击力的削减效果十分明显,主要是由于该装置具有较好拨转船头效果。钢-UHPC组合式防撞浮箱在实际应用中具备良好的防撞性能,可起到保护桥墩、防止桥墩破坏的作用。

A collision recovery algorithm using optimal Q parameter based on BIBD in RFID

In this work,an optimal Q algorithm based on a collision recovery scheme is presented. Tags use BIBD-( 16,4,1) codes instead of RN16 s. Therefore,readers can make a valid recognition even in collision slots. A way of getting the optimal slot-count parameter is studied and an optimal Q algorithm is proposed. The theoretical and simulation results show that the proposed algorithm can improve reading efficiency by 100% more than the conventional Q algorithm. Moreover,the proposed scheme changes little to the existing standard. Thus,it is easy to implement and compatible with ISO 18000-6C.

Injury severity analysis： comparison of multilevel logistic regression models and effects of collision data aggregation

This paper describes an empirical study aiming at identifying the main differences between different logistic regression models and collision data aggregation methods that are commonly applied in road safety literature for modeling collision severity. In particular, the research compares three popular multilevel logistic models （i.e., sequential binary logit models, ordered logit models, and multinomial logit models） as well as three data aggregation methods （i.e., occupant based, vehicle based, and collision based）. Six years of collision data （2001-2006） from 31 highway routes from across the province of Ontario, Canada were used for this analysis. It was found that a multilevel multinomial logit model has the best fit to the data than the other two models while the results obtained from occupant-based data are more reliable than those from vehicle- and collision-based data. More importantly, while generally consistent in terms of factors that were found to be significant between different models and data aggregation methods, the effect size of each factor differ sub- stantially, which could have significant implications forevaluating the effects of different safety-related policies and countermeasures.

On the Construction of Deepening Anti - corruption Mechanism

It needs the foundation of system and the guarantee of organizational system for anti-corruption,but it is more necessary to build and form an effective anti-corruption mechanism,so that the anti-corruption can be really put into practice. Anti-corruption mechanism refers to a organic operation system of the interaction,interconnection and constraint between the constituent elements( parts) and elements of national anti-corruption,and as a system,anti-corruption mechanism should have the characteristics of system aticness,comprehensiveness,transparency,legalization,public participation,scientific dynam ic,and internationalism. The construction of deepening anti-corruption mechanism is the need for reconstructing the ruling legitimacy of the party and the governm ent. Adhering to the principle of treating both root causes and symptoms is necessary in the construction of anti-corruption m echanism,com bating and punishing corruption is an important part of anti-corruption,and the prevention and control of corruption is the basic project of anti-corruption. Therefore,the construction of prevention and control mechanism in the anti-corruption mechanism has a more far-reaching significance.

波折钢板-钢覆复合材料防撞设施抗撞性能

为探究撞击作用下波折钢板-钢覆复合材料防撞设施的撞击响应和破坏模式,采用非线性有限元软件LS-DYNA,建立了船-防撞设施-桥碰撞的数值仿真模型,比较计算结果与试验结果,验证数值模拟方法的有效性,并通过参数分析探明了船舶冲击速度、钢面板厚度、冲击角度对防撞设施防护性能的影响规律。结果表明:有限元方法可以准确模拟碰撞产生的钢箱变形,考虑钢材应变率效应方法获得的钢箱凹陷深度和加速度峰值与试验值误差均小于10%;冲击速度、钢面板厚度、冲击角度对防撞设施在实际应用中的防护效果有较大影响,防撞设施在不同撞击作用下均起到良好的防护效果,展现出其良好的抗冲击性能和广泛的适用性。

升船机钢丝绳-缓冲油缸防撞装置的动力学计算方法

钢丝绳-缓冲油缸防撞装置目前已在多座升船机中得到应用,其防撞吸能是一个较为复杂的动力学过程,目前还未有研究涉及。根据钢丝绳-缓冲油缸防撞装置的工作原理,在考虑水体对船舶的水动力作用、钢丝绳弹性变形、缓冲油缸溢流阀的限载功能等因素的条件下,建立包括船舶和钢丝绳-缓冲油缸防撞装置的两阶段二阶非线性动力学模型,提出对升船机钢丝绳-缓冲油缸拦阻吸能装置关键性能参数进行分析的数值计算方法和防撞装置安全性评估方法。应用提出的方法对向家坝升船机钢丝绳-缓冲油缸防撞装置进行了动力学数值仿真计算,并与向家坝升船机实船撞击试验结果进行了比较分析,说明提出的动力学计算方法与实船试验结果基本吻合且偏于安全,可为钢丝绳-缓冲油缸防撞装置的设计和校核提供参考。