无线传感器网络Range-free自身定位算法仿真分析

定位技术是无线传感器网络重要的支撑技术之一。文章在总结有关定位算法的文献和研究成果的基础上。介绍了6种代表性的Range-free定位算法的原理，在Matlab环境下构造了网络拓扑场景进行了仿真实验，对6种代表性算法的性能进行比较并分析总结，指出了今后无线传感器网络定位算法的研究中所需解决的问题。

一种分布式的无线传感器网络Range-free节点定位算法

针对无线传感器网络在实际应用环境中节点分布往往不均匀的状况,提出了一种分布式、无需测距设备支持的节点自身定位算法(简称为NCL算法)。NCL算法基于节点通信邻域内邻居节点的个数估算节点间距,并在计算节点坐标时对节点间距进行加权平均以提高定位精度。使用OMNeT++对NCL算法进行仿真,并与DV-Hop算法进行比较分析。仿真结果表明,NCL算法提高了非均匀网络中的定位精度,具有较小的通信开销,并具有一定的容错性和自适应性。

基于Range-free的WSN定位技术研究

通过对无线传感器网络WSN中的非测距定位(Range-free)技术进行分析,阐述非测距定位技术的基本思想,并对一些经典的非测距定位技术进行研究与比较。首先,阐述WSN中非测距定位技术的主要思想;其次,分析和比较一些典型的非测距定位技术;最后,分析非测距定位技术的研究现状与发展趋势。

无线传感器网络Range-free节点定位算法研究

作为一种全新的信息获取和处理技术,无线传感器网络在现代社会中起着越来越大的作用,其中网络节点的自身定位是应用的前提条件。综合分析大量无线传感器网络节点定位算法相关文献,详细说明一些常见无线传感器网络range-free自身定位算法并对其中一些改进算法进行介绍。通过对这些算法进行比较,指出未来的研究方向。

A Highly Compact Third-Order Silicon Elliptical Micro-Ring Add-Drop Filter with a Large Free Spectral Range

We demonstrate a highly compact third-order elliptical micro-ring add-drop filter based on a silicon-on-insulator wafer. The elliptical micro-ring resonator has a major radius of 6μm （minor radius of 4.112μm） and a large free spectral range of 18 nm. Experimental results show a box-like channel dropping response, which has a 3 dB bandwidth of -2.7nm, high out-of-band signal rejection of around 40dB and a very low drop loss （〈0.5dB）. Simulation agrees well with the experiments. The footprint of the whole chip is only 0.0003mm2.

Distortion-Free Data Embedding Scheme for High Dynamic Range Images

Distortion-free data embedding is a technique which can assure that not only the secret data is correctly extracted but also the cover media is recovered without any distortion after secret data is extracted completely. Because of these advantages, this technique attracts the attention of many researchers. In this paper, a new distortion-free data embedding scheme for high dynamic range （HDR） images is proposed. By depending on Cartesian product, this scheme can obtain higher embedding capacity while maintaining the exactly identical cover image and stego image when using the tone mapping algorithms. In experimental results, the proposed scheme is superior to Yu et aL＇s scheme in regard to the embedding rate——an average embedding rate of 0.1355 bpp compared with Yn et aL＇s scheme （0.1270 bpp）.

<i>Campylobacter, Salmonella</i>and <i>Escherichia coli</i>Food Contamination Risk in Free-Range Poultry Production System

Livestock such as poultry is consumed as food worldwide and it constitutes one of the main protein sources for diners, as well as an important source of revenue generation for farmers. Poultry meat production chain identifies a significant role of the farm to folk. Most often, the systems used in poultry production can result in a higher prevalence of Campylobacter, Salmonella, and Escherichia coli contamination, leading to adverse health effects with detrimental consequences. The method of poultry keeping plays a significant role in the poultry meats’ outcome and its food safety standards. Farmers attempt to develop new poultry operations, however, there are two main possibilities;to operate within the present vertically integrated system which is incredibly good for disease prevention and to develop independently, or a smaller operation that is more animal friendly. This article reviews the available research on the impact of free-range poultry production systems on food safety, most importantly the prevalence and control of Campylobacter, Salmonella and Escherichia coli in free-range production systems. The results suggest a conflicting view when bacterial loads of poultry meat from conventional and free-range systems are compared. Studies have shown increased bacterial loads in a free-range production system.

Dynamic Free-Spectral-Range Measurement for Fiber Resonator Based on Digital-Heterodyne Optical Phase-Locked Loop

We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 × 10?9 and a dynamic locking accuracy of about 5 × 10?8 are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on.

An Evaluation of the Infection Status and Source of Subgroup J Avian Leukosis Virus in Cloned Free-Range Layers

In recent years, subgroup J avian leukosis virus （ALV-J） has been found to frequently infect layers in China. This virus is responsible for economic losses due to both mortality and decreased performance in chickens. In this study, 45-d-old cloned flee-range layers were suspected to be infected with ALV and other immunosuppressive diseases because their feathers were unkempt and their growth rate was impaired. To estimate the infection status and determine the source of ALV-J in the flock, 30 cloacal swabs were randomly collected to measure the p27 antigen level by enzyme-linked immunosorbent assay （ELISA）. Among the birds that were tested, 87% （26/30） were positive. In addition, 6 anticoagulant blood samples were aseptically collected at random from the flock when the layers were 60 d old. These samples were centrifuged to obtain the leukocytes, which were then used to inoculate chicken embryo fibroblast （CEF） cells for the identification of ALV-J by indirect immunofluorescence （IFA）. Of the samples tested, 100% （6/6） were positive. The flock＇s production performance was also investigated, and 10 layers were necropsied to evaluate pathological changes at 115 d of age. The flock never laid eggs even though they reached the age of the first laying （110 d）. Furthermore, there were pathological changes present, including atrophy of the thymus and bursa of Fabricius, undeveloped ovaries, glandular stomach haemorrhage, and hepatosplenomegaly. Paraffin-embedded sections of intumescent liver and spleen were prepared for antigen localisation using IFA. Positive signals were prevalent in paraffin-embedded sections of the intumescent liver and spleen. Furthermore, provirus DNA was extracted from 4 cloned flee-range layers, and 2 patemal parents （HR native cocks）, and the gp85 gene of ALV-J was amplified by PCR to analyse the genetic variation. The results of the autogenous variation analysis showed that the 6 strains were 98.5-99.7% homologous. This study indicated that there was persistent infection with ALV-J by dynamic inspection, which seriously reduced the production performance of the flock. In addition, the genetic variation analysis showed that ALV-J in the flock was more likely to have originated from the paternal parent, the HR native cock.

Effects of Different Facilities on Laying Performance,Egg Quality and Air Quality for Layers Under Free Range System

[ Objective] This paper aimed to study the effects of different facilities on laying performance, egg quality and air quality for commercial layers under free range system. [Metbod] The single factorial arrangement was used in the tdal. 2 800 commercial Beijing You Chicken （BYC） at 23 weeks of age were chosen and randomly divided into four groups, three replicates each group, and 210 birds each replicate. The layers lived in loose housing condition with deep litter inside. Group 1 was the control, equipped with standard laying boxes, and flat-type perches; group 2 was e- quipped with common laying boxes, and flat-type perches; group 3 was equipped with common laying boxes, and erect-type perches, and group 4 was equipped with standard laying boxes, and erect-type perches. The laying performance, laying position and egg quality of birds during 24 to 32 weeks of age were recorded and measured, and average NH3, CO~ concentration of each group at 32 weeks of age were measured and detected. [Result] The results showed that laying performance of commercial BYC under loose housing condition were significantly different during 24 -32 weeks of age. The laying rate of the control group equipped with flat-type porches and standard laying boxes （33.25%） was significantly higher than in group equipped with flat-type perches and common laying boxes （21.83%） （P〈0.05）, and other two groups （26.04% and 27.48%） （P 〈0.05）. The ratio of floor eggs was significantly lower in groups with standard laying boxes than in the groups with common laying boxes （P 〈0. 05）, and the laying proportion in the first floor of layer boxes were much higher than those in the second floor （ P 〈 0.05）. There were no significant differences on egg quality among the groups （P〉0.05）. Average NH3, CO2 concentration of group 3 and 4 at 82 weeks of age were both signifi- cantly higher than of group 1 and 2 （P 〈0.05）. [ Conclusion] All of the above indicated that the utilization of facilities could improve layer＇s laying rate, especially with flat-type perches and standard laying boxes, and the indoor air quality was also affected to some extent.

Time-optimal rendezvous transfer trajectory for restricted cone-angle range solar sails

The advantage of solar sails in deep space exploration is that no fuel consumption is required. The heliocentric distance is one factor influencing the solar radiation pressure force exerted on solar sails. In addition, the solar radiation pressure force is also related to the solar sail orientation with respect to the sunlight direction. For an ideal flat solar sail, the cone angle between the sail normal and the sunlight direction determines the magnitude and direction of solar radiation pressure force. In general, the cone angle can change from 0° to 90°. However, in practical applications, a large cone angle may reduce the efficiency of solar radiation pressure force and there is a strict requirement on the attitude control. Usually, the cone angle range is restricted less more than an acute angle （for example, not more than 40°） in engineering practice. In this paper, the time-optimal transfer trajectory is designed over a restricted range of the cone angle, and an indirect method is used to solve the two point boundary value problem associated to the optimal control problem. Relevant numerical examples are provided to compare with the case of an unrestricted case, and the effects of different maximum restricted cone angles are discussed. The results indicate that （1） for the condition of a restricted cone-angle range the transfer time is longer than that for the unrestricted case and （2） the optimal transfer time increases as the maximum restricted cone angle decreases.

基于F-B NCP函数的可行QP-free算法

本文得到一种可行QP-free算法,引入ε-有效集策略使得每次迭代只需求解规模较小的线性方程组得到迭代方向,且方程组只包含工作集中的约束,其规模较原问题大大减小,同时不进行弧搜索,从而降低了运算量.

Process for improving the ladle free- opening rate for high aluminum steel in continuous casting

Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.

Development of Debris-free Laser Plasma Sources for EUV Lithography in CIOMP

We have been developing debris-free laser plasma sources for EUV lithography since 1996. Two types of debris-free sources, such as cryogenic target and gas-puff target laser plasma sources, were designed and built up in CIOMP. EUV radiation spectra of the sources with a variety of targets have been obtained by different ways.

The Equilibrium Range of Wind Wave Spectra: an Explanation Based on White Noise

Laboratory experiments and field observations show that the equilibrium range of wind wave spectra presents a – 4 power law when it is scaled properly. This feature has been attributed to energy balance in spectral space by many researchers. In this paper we point out that white noise on an oscillation system can also lead to a similar inverse power law in the corresponding displacement spectrum, implying that the – 4 power law for the equilibrium range of wind wave spectra may probably only reflect the randomicity of the wind waves rather than any other dynamical processes in physical space. This explanation may shed light on the mechanism of other physical processes with spectra also showing an inverse power law, such as isotropic turbulence, internal waves, etc.

EXACT SOLUTION FOR RECTANGULAR SLAB WITH THREE EDGES SIMPLY-SUPPORTED AND OTHER FREE

In this paper,we give all-sided pastic analysis of the rectangular slab with three edges simply-supported and other free.Here we discuss the following four cases:(1)The uniformly distributedload over the area a slab.(2).A concentrated load act at midpoint of free edges slab.(3)A concen-trated load act at the center a slab.(4)The line load act along free edge of slab.

Influence of 10-(6-plastoquinonyl) decyltriphenylphosphonium on free-radical homeostasis in the heart and blood serum of rats with streptozotocin-induced hyperglycemia

BACKGROUND It is known that under conditions of tissue tolerance to insulin,observed during type 2 diabetes mellitus(DM2),there is an increased production of reactive oxygen species.Moreover,the free radicals can initiate lipid peroxidation(LPO)in lipoprotein particles.The concentration of LPO products can influence the state of insulin receptors,repressing their hormone connection activity,which is expressed as a reduction of the glucose consumption by cells.It is possible that reduction in glucose concentration during administration of 10-(6-plastoquinonyl)decyltriphenylphosphonium(SkQ1)to rats with DM2 may be related to the antioxidant properties of this substance.AIM To establish the influence of SkQ1 on free-radical homeostasis in the heart and blood serum of rats with streptozotocin-induced hyperglycemia.METHODS To induce hyperglycemia,rats were fed a high-fat diet for 1 mo and then administered two intra-abdominal injections of streptozotocin with a 7-d interval at a 30 mg/kg of animal weight dose with citrate buffer equal to pH 4.4.SkQ1 solution was administered intraperitoneally at a 1250 nmol/kg dose per day.Tissue samples were taken from control animals,animals with experimental hyperglycemia,rats with streptozotocin-induced glycemia that were administered SkQ1 solution,animals housed under standard vivarium conditions that were administered SkQ1,rats that were administered intraperitoneally citrate buffer equal to pH 4.4 once a week during 2 wk after 1-mo high-fat diet,and animals that were administered intraperitoneally with appropriate amount of solution without SkQ1(98%ethanol diluted eight times with normal saline solution).To determine the intensity of free radical oxidation and total antioxidant activity,we used the biochemiluminescence method.Aconitate hydratase(AH),superoxide dismutase,and catalase activities were estimated using the Hitachi U-1900 spectrophotometer supplied with software.The amount of citrate was determined by means of the Natelson method.Real-time polymerase chain reaction was carried out using an amplifier ANK-32.RESULTS It was found that the mitochondrial-directed antioxidant elicits decrease of biochemiluminescence parameter values that increase by pathology as well as the levels of primary products of LPO,such as diene conjugates and carbonyl compounds,which indicate intensity of free radical oxidation.At the same time,the activity of AH,considered a crucial target of free radicals,which decreased during experimental hyperglycemia,increased.Apparently,increasing activity of AH influenced the speed of citrate utilization,whose concentration decreased after administering SkQ1 by pathology.Moreover,the previously applied antioxidant during hyperglycemia influenced the rate of antioxidant system mobilization.Thus,superoxide dismutase and catalase activity,as well as the level of gene transcript under influence of SkQ1 at pathology,were changing to the direction of control groups values.CONCLUSION According to the results of performed research,SkQ1 can be considered a promising addition to be included in antioxidant therapy of DM2.

基于DEA-Malmquist模型的散养奶牛效率评价及对策研究

文章在国内奶牛规模化养殖的背景下,针对现有散养奶牛的个别省份进行效率评价,为今后发展提供理论依据。基于2012~2021年散养奶牛的相关数据,采用DEA-Malmquist模型对散养奶牛效率进行了测算。结果表明,散养奶牛整体效率未达到DEA有效,主要原因取决于规模效率,仅2016~2017年、2017~2018年时间段内,散养奶牛效率有所提高,其余时间段均降低,尤其2018~2020年时间段内快速降低;2012~2021年期间山西和新疆散养奶牛效率提高,吉林、湖南、陕西散养奶牛效率降低。依据研究结果,实施差异化的发展策略和注重散户养殖人员的技术培训是散养奶牛今后发展的路径选择。

夹角修正的DV-hop传感器网络节点定位研究

位置信息对于无线传感器网络中的事件监测必不可少,考虑到传感器网络中节点能量和资源受限的特性,针对现有定位方法的不足,提出距离无关的ARDV-hop算法,通过夹角修正方式以提高定位精度。该方法先基于传统DV-hop算法获取平均每跳距离,然后逐一选取锚节点间通信线路中部的节点,通过该节点与两端锚节点的夹角来修正平均每跳距离,从而提高全网节点定位的准确性。仿真实验结果表明夹角的修正方式对于提高定位精度十分有效,即使在网络中节点分布不均匀的情况下仍能准确定位。

基于强度-相位级联调制的微波光子下变频法

为了优化微波光子下变频的无杂散动态范围,结合带反馈控制的强度调制器和相位调制器,提出并验证了基于强度和相位级联调制的微波光子下变频方法。通过理论推导和仿真分析了下变频原理以及本振功率对系统性能的影响,搭建了强度-相位级联调制的微波光子下变频系统,利用自行研制的直流偏置反馈控制模块确保强度调制器的工作状态稳定,对系统进行了性能测试。实验结果表明,增益和无杂散动态范围分别为-6.65dB和108.62dB/Hz^(2/3),与传统的强度调制器级联下变频链路相比,增益和无杂散动态范围分别提高了3.56dB和19.87dB。基于强度和相位级联调制的下变频方法仅需要单个偏置电压,且可通过反馈模块实现工作状态的稳定控制,系统结构简单、性能稳定,可实现大动态范围的微波光子下变频。