自反二元关系下不完备信息系统的粗糙熵及粒度度量

针对不完备信息系统中各种自反二元关系形成了对系统的覆盖而非划分的情况,提出利用对象的邻域来定义粗糙熵和粒度度量以衡量系统的不确定性,证明了以上不确定性度量同完备信息系统的不确定性度量是一致的.同时在覆盖可约简的情况下,定义了覆盖约简对系统的粗糙熵和粒度度量,研究结果表明在系统分类最细或最粗时,覆盖约简的不确定性和知识的不确定性是等价的.

基于粒度度量的不完备序信息系统约简算法

在不完备序信息系统中,引入了序关系的定义,通过将不完备序信息系统转换为扩展序值表,讨论了扩展序值表中知识的粒度大小,定义了知识的粒度度量方法,证明了知识的粒度度量随着知识划分变大而单调增加的定理,给出了相关的性质,提出了一种新的基于粒度度量的不完备序信息系统约简算法,并通过实例验证了算法的有效性。

基于行为的可信动态度量的状态空间约简研究

针对复杂并发计算机系统行为可信的动态度量研究中,细粒度动态度量所引发的状态空间爆炸问题一直是研究的难点.文中基于并发理论研究复杂并发计算机系统行为可信问题,在保障度量可靠性的前提下对系统状态空间进行约简,即通过标记变迁系统模型描述行为系统,通过事件结构模型研究行为关系,依据行为关系对变迁系统中各条路径进行重构,合并重构路径中相同的路径,实现变迁关系集约简,缩小状态空间.通过上述方法缓解了状态空间爆炸,并且,根据约简后的状态空间得到面向行为的可信动态度量的行为预期,增加细粒度动态度量方法在复杂系统中应用的可行性.

基于最大决策邻域粗糙集的不确定性度量方法

邻域粗糙集模型是经典粗糙集模型的变型,对处理数值型数据具有较好的优势性.本文引入最大决策邻域粗糙集模型,该模型密切关注边界样本,通过增加与决策类有最大交集的邻域样本来扩大正域,并在该模型上定义了最大决策粗糙度的概念.为了能够反映正域、负域的同时变化,提出一种基于边界域的不确定性度量方法.为了能够更全面的度量,在最大决策邻域粗糙集模型中定义了最大决策邻域粒结构,并基于该粒结构提出了最大决策邻域粒度概念,该粒度是对信息系统的分类能力的度量.文章最后提出一种基于最大决策邻域粗糙集的混合不确定性度量方法,将两种度量方法进行结合.实验结果表明,所提出的度量方法在邻域信息系统中具有较好的分类效果.

Effects of temperature, particle size, and air humidity on sensibility of typical high-energetic explosives

The production and utilization of high-energetic explosives often pose a range of safety hazards,with sensitivity being a key factor in evaluating these risks.To investigate how temperature,particle size,and air humidity affect the responsiveness of commonly used high-energetic explosives,a series of BAM(Bundesanstalt für Materialforschung und-prüfung)impact and friction sensitivity tests were carried out to determine the critical impact energy and critical load pressure of four representative high-energetic explosives(RDX,HMX,PETN and CL-20)under different temperatures,particle sizes,and air humidity conditions.The experimental findings facilitated an examination of temperature and particle size affecting the sensitivity of high-energetic explosives,along with an assessment of the influence of air humidity on sensitivity testing.The results clearly indicate that high-energetic explosives display a substantial decline in critical reaction energy when subjected to micrometre-sized particles and an air humidity level of 45%at a temperature of 90℃.Furthermore,it was noted that the critical reaction energy of high-energetic explosives diminishes with an increase in temperature within 25℃−90℃.In the same vein,as the particle sizes of high-energetic explosives increase,so does the critical reaction energy for micrometre-sized particles.High air humidity significantly affects the sensitivity testing of high-energetic explosives,emphasizing the importance of refraining from conducting sensitivity tests in such conditions.

实值决策信息系统中基于近似等价类的不确定性度量

信息系统是知识的表示形式,是人工智能中的重要模型。信息系统描述的是每一个对象在任意属性下通过某一特定函数构成信息函数值的信息表,实值信息系统表示信息函数值都是实数的信息系统。在信息系统中,任意属性子集下要使两个对象处于同一等价类,则需要它们的信息函数值完全相等,这在实值决策信息系统中是很难做到的,基于这样的原因,提出了实值决策信息系统中的近似等价类,进一步研究实值决策信息系统中熵度量和粒度度量的不确定性度量方法,并证明在近似等价下定义的熵度量和粒度度量都具有单调性。这些研究结果对于进一步研究实值决策信息系统中的属性约简将会有很大的帮助。

Cross-Layer Framework for Fine-Grained Channel Access in Next Generation High-Density Wi Fi Networks

Densely deployed Wi Fi networks will play a crucial role in providing the capacity for next generation mobile internet. However, due to increasing interference, overlapped channels in Wi Fi networks and throughput efficiency degradation, densely deployed Wi Fi networks is not a guarantee to obtain higher throughput. An emergent challenge is how to effi ciently utilize scarce spectrum resources, by matching physical layer resources to traffi c demand. In this aspect, access control allocation strategies play a pivotal role but remain too coarse-grained. As a solution, this research proposes a flexible framework for fine-grained channel width adaptation and multi-channel access in Wi Fi networks. This approach, named SFCA(Subcarrier Fine-grained Channel Access), adopts DOFDM(Discontinuous Orthogonal Frequency Division Multiplexing) at the PHY layer. It allocates the frequency resource with a subcarrier granularity, which facilitates the channel width adaptation for multi-channel access and thus brings more fl exibility and higher frequency efficiency. The MAC layer uses a frequencytime domain backoff scheme, which combines the popular time-domain BEB scheme with a frequency-domain backoff to decrease access collision, resulting in higher access probability for the contending nodes. SFCA is compared with FICA(an established access scheme)showing significant outperformance. Finally we present results for next generation 802.11 ac Wi Fi networks.

Infrared measurement of temperature field in coal gas desorption

In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared video signals obtained by the experiment are processed with SAT.Then the infrared radiation signals are processed by EMD with Hilbert–Huang and the infrared radiation noise is effectively removed.The research results show that the desorption process,with the change of the temperature,is an endothermic process.The coal absorbs heat when the gas is desorbed and the temperature drops.The coal body temperature drop range is obviously related to coal particle size.The smaller the particle size is,the bigger the temperature drop becomes.The temperature variation curves in the process of coal gas desorption under different particle sizes are fitted,and they comply with the exponential function.The research results lay the theoretical and experimental foundation for non-contact prediction on working face of coal and gas outburst with infrared thermal image technology.

Flow Field Around Rushton Turbine in Stirred Tank by Particle Image Velocimetry Measurement

In this paper, particle image velocimetry (PIV) was used to measure the mean and root meansquare(RMS) velocity in the stirred tank with six-flat blade Rushton turbine and with no baffles. Two typesof motion patterns were studied. One was that the impeller runs at constant speed, the other was that the impellerruns at time-dependent speed and in a periodic way. The emphasis of the paper was on the comparison of meanand RMS velocity vector maps and profiles between these two types of motion patterns, and especial attention waspaid to the comparison of the mean velocity, time-averaged RMS velocity, phase averaged RMS velocity betweenthe constant 3 RPS (revolution per second) and time-dependent operation. The Reynolds number was between 763and 1527. The study explained the mechanism that time-dependent RPS is more efficient for mixing than that ofconstant RPS.

Effects of water salinity and content on particle size distribution and soil strength

The effect of NaCl on soil strength was investigated in this project based on salinity concentrations of 0 g/L, 5 g/L, 20 g/L, and 50 g/L as well as varying water contents of 15%-20%. Laser particle size analyzer was also performed to explain possible effects. From particle size analysis and strength tests, it is hypothesized that the strength of the soil is increased with the addition of certain salinity concentrations until there are reversed effects, which is between 20 g/L and 50 g/L from our study. The increase of strength is suggested to be the affect of a greater variety of particle sizes. Since NaCI plays a role in the particle size distribution, it also plays a role in the strength of soils. The degree of the effect of the water content also differs from concentrations, and could be due to the variation of hydration film thickness on particles, which is affected by the ions introduced from water.

Effect of different milling processes on the mineral distribution in a coal powder

Coal samples obtained from Wanbei(WB),Pingxiang(PX),Liupanshui(LP),and Datong(DT) mines were pulverized,using either a vibration mill or a ball mill,to different degrees of fineness.The effect of the different grinding methods on the mineral distribution within the pulverized coal was investigated by using proximate analysis,particle size analysis,and float-sink tests.The results show that the ash content in WB,PX,and DT coal increases with increasing particle size overall,while the ash content of the LP coal remain almost the same within each size fraction.In that case the ash in each fraction is similar to that of the raw coal.The ash versus size distributions for the same coal sample milled with the same grinding method to different degrees of fineness are similar.The ash versus size distribution of the coal powder with a 15% screen residue that was prepared with the vibration mill is different from the distribution of a similar sample prepared with a ball mill.The curves also vary between different coal samples.The grinding method has a great influence on the distribution of minerals across the various particle sizes.The float-sink tests and the laser particle size analysis results on PX and DT coal samples show that fines dominate the higher density fractions although the large +2.0 g/cm3 fraction was dominated by coarse particles.The size distribution of the low density fraction and +2.0 g/cm3 density fraction is bimodal.The size distribution of the intermediate density fraction is multimodal.

Measuring Telomere Length in Proliferating Cells by Flow-FISH Method

The purpose of present work is a measurement of telomere length dynamic in proliferating cells in vitro by modified flow-FISH method. This method is a combination of two modifications： telomere length measurement in differentiated cells by surface antigen and analysis of cells divisions＇ number by vital dye dilution. Lymphocytes were activated by anti-CD3 Abs with IL-2 presents and grown in vitro for 7 days. Cells division＇s number was measured by dilution of CFSE vital dye which cells were stained previously activation. For telomere length measurement we used flow-FISH method with Cy3 labeled telomere PNH probe. Using this method we evaluated the dynamic of telomere length in CD4＋ and CD8＋ T-cells after 7 days culturing in vitro and revealed the difference in telomere lengthening and shortening versus division rounds in cell subsets. In CD8＋ cells telomeres start lengthen on a second division with the maximum on 4th division round becoming more that 20% longer compared with undividing cells. In CD4＋ cells telomeres did not have any length peculiarities through all division rounds demonstrating different telomere regulation in subsets. This probably occurs due to the higher level ofhTERT protein expression in CD8＋ than CD4＋ cells do.

Nanoparticle distribution in a rotating curved pipe considering coagulation and dispersion

We study the evolution of the particle number concentration, mass concentration, particle polydispersity, particle diameter and geometric standard deviation considering particle coagulation and dispersion in a rotating curved pipe at different Reynolds number, Schmidt number and F number. It is found that, when the Coriolis force and the centrifugal force point to the same direction, particles concentrate near the outside edge of the pipe, which becomes more obvious as time goes by. The particle number and mass concentration increase faster at the early stage than that at the later stage, and approach a stable value finally. As the coagulation proceeds, the particle diameter, polydispersity and geometric standard deviation increase and have high values in the region close to the outside edge of the pipe. When the Coriolis force and the centrifugal force point to the oppo- site direction and the Coriolis force is more dominant than the centrifugal force, particles concentrate near the inside edge of the pipe. The particles in the region with a high number concentration have high mass concentration, large diameter and high polydispersity as well as large geometric standard deviation. The particle distribution is dependent on the balance of the pipe curvature and rotating speed. The Reynolds number and the Schmidt number have effects on the particle distribution when other parameters remain unchanged. An increase in the Reynolds number leads to an increase in particle number concentration and mass concentration, and a decrease in particle polydispersity, particle diameter and geometric standard deviation. With the increase of Schmidt number the particle number concentration and mass concentration increase, and the particle polydispersity, particle diameter and geometric standard deviation decrease.