再访GI/M/1排队

通过构造两个向量马氏过程重新探讨了GI/M/1排队,某些新结果如忙期和闲期的 联合分布被得到了.这一方法容易推广到服务时间为无限位相型分布的GI/SPH/1排队.     

基于移动边缘计算的GI/GI/1排队建模与调度算法EI北大核心CSCD

针对车联网环境下路侧边缘计算节点部署不均衡、服务密度小、实时调度计算压力大等问题,提出一种基于智能车移动边缘计算(Mobile edge computing,MEC)的任务排队建模与调度算法,提供弹性计算服务,将具备感知、计算、控制功能的智能车作为移动边缘计算服务器,设计了车联网环境下的MEC体系架构.首先基于虚拟化技术对智能车进行虚拟化抽象,利用排队论对虚拟车任务构建了GI/GI/1排队模型.然后基于云平台Voronoi分配算法对虚拟车任务进行分配绑定,进而实现了智能车的优化调度与分布式弹性服务,解决了边缘计算任务分配不均衡等问题.最后通过城市交通路网中的车辆污染排放的实时计算实验,验证了该方法的有效性.     

Internet的新发展和NI/GI建设

本文从技术的角度，介绍当前Ｉｎｔｅｒｎｅｔ的发展和ＮＩ／ＧＩＩ的建设，对某些关键性的问题提出了自己的看法和见解。     

GI/Gm排队系统梯度估计的一种新方法

梯度估计是研究复杂离散事件动态系统的关键问题之一.这里对GI/G/m排队系统提 出一种新方法,在一次采样(仿真)的基础上,通过分析采样路径,可得到性能指标关于参数的 局部函数表达式.由此可直接求导,得到采样梯度,并证明了由该方法得到的梯度估计的无偏 性.该方法计算量小、精度高,还可以进一步拓广到其它系统上.     

可修排队系统GI/G(M/G)/1的可靠性分析

利用更新过程理论和向量马氏过程方法全面考察了可修排队系统GI/G(M/G)/1的结 构,得到了所有感兴趣的指标,并证明了服务台的可靠性指标只与系统的忙期、闲期和忙期循 环时间有关.     

全球首款Android手机GI拆解

本文对业内首款采用了Google公司Android手机平台的智能手机T—mobileG1进行了拆解。与具有类似功能的同类智能手机相比,G1的价格还不到其它产品的2／3。在易用性方面,G1也非常出色,它具有3种输入用户接口,包括触摸屏、5行QWERTY键盘,以及轨迹球鼠标。目前具有这3种输入接口的智能手机仅有wILLc0MD4。多个用户接口的优势在于可以根据不同的应用场合选择合适使用的接口。不过,这款手机的触摸屏不具备多触点功能,不能同时检测多个触摸动作。     

Stationary time characteristics of the <Emphasis Type="Italic">GI/M/n</Emphasis>/∞ system with some variants of the generalized renovation discipline

Consideration was given to the queuing system with recurrent arrivals, exponential distribution of the service time, infinite buffers, and the following variants of the discipline of generalized renovation and service: inversive order of renovation with direct order of customer service and direct and inversive orders of renovation with inversive order of customer service. For the serviced and lost customers, the stationary time characteristics of sojourn in the buffer were determined     

Level–phase independent stationary distributions for GI/M/1-type Markov chains with infinitely-many phases

GI/M/1-type Markov chains are two-dimensional processes, with one dimension called the level and the other the phase. When such a chain is positive-recurrent and the phase space is finite, much is known about the properties of the stationary distribution. In particular, it is known how to derive the decay rate as the level variable approaches infinity. However, when the phase space is infinite, the properties are more complicated. A range of decay rates may be achievable and the transition structure at the boundary has a strong influence on the stationary distribution.     

Stabilization of a class of switched nonlinear systems

The stabilization of a class of switched nonlinear systems is investigated in the paper. The systems concerned are of （generalized） switched Byrnes-Isidori canonical form, which has all switched models in （generalized） Byrnes- Isidori canonical form. First, a stability result of switched systems is obtained. Then it is used to solve the stabilization problem of the switched nonlinear control systems. In addition, necessary and sufficient conditions are obtained for a switched affine nonlinear system to be feedback equivalent to （generalized） switched Byrnes-Isidori canonical systems are presented. Finally, as an application the stability of switched lorenz systems is investigated.     

Use of a super‐resolution method in interpretation of forests from multiple NOAA/AVHRR images

Super‐resolution methods take several images from the same location and fuse them into one, called a super‐resolution image. If the fusion is carried out correctly, it is possible to recognize details from the super‐resolution image which are not visible in the original images. In this study, a super‐resolution technique is applied to sequences of National Oceanic and Atmospheric Administration, Advanced Very High Resolution Radiometer (NOAA/AVHRR) scenes using a varying number of images and acquisition times, in order to determine whether it is possible to recognize forested and non‐forested areas from NOAA/AVHRR images more accurately using a super‐resolution method than with the original images. The overall proportion of forest and the proportion of forest with a growing stock volume of over 50 m³/ha were calculated for each pixel, and the results evaluated using landscape indices, r.m.s. error (RMSE) and a parameter showing how large a proportion of the estimates are closer to the ground truth in the original image sequence than in the corresponding super‐resolution image. The results showed the super‐resolution estimates to be better in all cases than those based on the original image material, but the improvement was marginal. Neither the number of images nor the image acquisition time had any obvious effect on the results.     

Enhancement of heat transfer in a convergent/divergent channel by using carbon nanotubes in the presence of a Darcy–Forchheimer medium

This article explores the influence of thermal radiation on the flow and heat transfer of single-walled carbon nanotubes over both a convergent and divergent channel. Flow is induced due to a Darcy–Forchheimer medium. Further, the heat transfer mechanism is analyzed in the presence of a thermal radiation process. Guided by some appropriate similarity transformations, the fundamental PDEs are converted into a self-similar system of coupled non-linear ODEs. The findings are obtained with the help of the Runge–Kutta-45-based shooting method. The roles of the Reynolds number, porosity parameter, inertia coefficient parameter, Prandtl number and radiation parameter are presented graphically. Results are displayed and show that the rate of heat transfer is higher in a divergent channel as compared to a convergent channel.

     

A Study of Optimization and Rule/Goal Graph for a Logical Query

Static optimization of logical queries is,in substance,to move selections down as far as possible in evaluating logical queries.This paper extends Ullman‘s RGG(Rule/Goal Graph)^[6] and introduces Pgraph,with which a wide range of recursive logical queries can be statically optimized top-down and evaluated bottom-up,some of which are usually optimized by dynamic approaches.The paper also shows that for some logical queries the complexity of pushing selections down and computing bottom-up is related to the complexity of base relation in the queries.     

Synthesis of a Class of Non-linear Systems†

A problem in the practical application of the Volterra series to nonlinear theory is the synthesis of systems with a given set of Volterra kernels. In this article we present a method of determining whether a given Volterra kernel can be synthesized exactly by using only a finite number of multipliers. A method for the synthesis of such kernels is also presented. The use of the techniques discussed here is illustrated by examples.     

Denotational Semantics of a Simple Model of Eiffel

A simple abstract model of Eiffel is introduced,and its denotational semantics is defined using VDM style.A static analysis approach is presented to treat multiple inheritance and renaming mechanism.Within the framework of denotational semantics introduced in this paper,the key features of Eiffel,such as identification,classification,multiple inheritance,polymorphism and dynamic binding,can be adequately characterized.     

The Generation of a Sort of Fractal Graphs

We present an approach for generating a sort of fractal graphs by a simple probabilistic logic neuron network and show that the graphs can be represented by a set of compressed codings.An algorithm for quickly finding the codings,i.e.,recognizing the corresponding graphs,is given.The codings are shown to be optimal.The results above possibly give us the clue for studying image compression and pattern recognition.     

Die Macht der Bilder oder Everybody’s gonna be a Star for 15/10 of a Second

Nahezu alle Lebensvorg?nge und -bereiche werden heute weltweit verbildlicht. Videokameras, die unser Verhalten im ?ffentlichen und nicht-?ffentlichen Bereich aufzeichnen, Google, das unsere H?user filmt und sie weltweit zug?nglich macht; Facebook, das unsere Fotos scannt und unsere Gesichter identifiziert. Das nationale Datenschutzrecht und insbesondere das Unionsrecht lassen bislang überzeugende Antworten auf diese Verbildlichung des Alltags vermissen, Bilder werden als „normale“ personenbezogene Daten eingeordnet. Im Entwurf der Europ?ischen Kommission für eine Datenschutzgrundverordnung (DS-GVO) ist im Gegensatz etwa zum deutschen Recht die Videoüberwachung explizit nicht geregelt. Jedoch kommt Bildern eine besondere Macht zu. Sie wirkt sich deutlich auf die Pers?nlichkeitsrechte betroffener Personen aus. Mit den neuen Facetten der Macht der Bilder befasst sich der folgende Beitrag.