美丽的天文

始终相信星空的壮观,天文的美丽,绝不仅仅是高深的理论,枯燥的数字,为宣扬天文的艺术美,不懈追求,尽力探索,总是会沉醉于落日云霞的辉煌,流连于星汉灿烂的夜空,企盼有朝一日,走遍大江南北,能将无穷尽的星空美景,与世间秀水山川,融为一体,成为一个独特的天文艺术影廊,将星空的美,尽情挥洒。     

什么都有，什么都卖，什么都不奇怪

有这么一个国家,孔子是它们的,西施是它们的,李时珍是它们的,端午节是它们的,甲骨文是它们的,活字印刷术是它们的,中医是它们的,汉字是它们的,针灸是它们的,风水是它们的,亚洲是它们的,地球是它们的,火星是它们的,全宇宙都是它们的……这个国家,叫做韩国。     

基于JAVA的拟合二次函数的设计与实现

Java是一种简单的,面象对象的,分布式的,解释的,键壮的,安全的,结构的,中立的,可移植的,性能很优异的多线程的,动态的语言。该文用JAVA实现拟合二次函数,随机选取六组数据,求解相关系数矩阵的值,带入数据求出真值,最后对结果进行验证,结果显示达到了预期效果。     

基于JAVA的简单计算器的设计与实现

计算器是当今社会较常见的电子产品之一。随着科学技术发展的日新日异,计算器已经在生活中无处不在。它大大降低了数字计算的难度,提高了计算的准确度和精确度,奠定了其它科学发展研究的基础。Java是一种简单的,面象对象的,分布式的,解释的,键壮的,安全的,结构的,中立的,可移植的,性能很优异的多线程的,动态的语言。该文基于AWT组,设计了GUI界面的计算器应用程序,完成简单的算术运算。通过设计,达到了预期功能效果。     

无限延伸的音乐 深圳车乐汇改英菲尼迪

正工作的繁忙,城市的喧哗,生活的紧压,总会让我们不经意间忘记享受,忘记享受音乐,忘记音乐带来的快乐,忘记音乐给生活带来的意义。人生就像一场不知道终点的赛跑,一味的狂跑只会错过沿途美丽的风景,适时的放慢脚步,美丽的风景就会陪伴左右,悄悄的关上车门,将繁杂的世俗拒之门外,播放喜爱的音乐,这时,终点其实已经在你眼前,用自己喜欢的声音为到达终点而欢呼,用音乐取悦自己的耳朵,用音乐缓解生活的压力,假如你     

百人再晒摄影包

到年终团聚时。每年这个时候,全国各地的影友,免不了参加大大小小的摄影年会,网站的,摄协的,杂志的,还有各种摄影组织摄影团体的。颁奖,合影,回顾,展望,联欢,鼓掌,起哄,拍美女,抽大奖……年年岁岁花相似,又     

脉脉情谊E卡牵，人醉焉

期盼,在春风里;梦想,在夏日里;思念,在飒飒秋风中;融融的冬日里,喜庆的节日中,为我们的亲人,友人,爱人送去一份美好的祝愿。虽然只是一句轻柔的祝福,却是我们的心语,祝福你的生活盛满了青春,盛满了希望,更蛊满了活力;虽然只是一张小小的贺卡,却牵着我们的情谊,悄然而至的卡片,浮现出美丽而甜蜜的回忆。朋友,让我们将双手放在胸前,轻轻地闭上眼睛,共同祈祷——丰富的昨天,美丽的今天,希望的明天,编织成你我,更美好的一年!通过网络贺卡送出我们的祝福,既时尚又快捷,在这一期的“凭窗侃网”栏目中,我们为朋友推荐六个比较有代表性的贺卡网站,每一个贺卡网站都是求同存异,各具特色,在我们发送贺卡的时候便可以有所选择,有所侧重。     

编辑词话

旅行,是一种果敢,放下的是眼前,拥抱的是世界;摄影,是一种激情,四溢的是情绪,张扬的是个性。旅行,是一种凝望,看到的是风景,领略的是世相;摄影,是一种审视,感悟的是内心,体味的是永恒。旅行,是一种修行,丈量的是心路,捡起的是空无;摄影,是一种回归,走出的是爱恨,唤回的是本真。旅行,近摄影,却不等于!本期采访翟东风、梁子两位人文旅行摄影家有感。     

TITAN新产品发布20城市巡回展

近年来,我国空间信息产业经受了前所未有的考验,同时也迎来了历史赋予我们的巨大机遇与挑战。东方泰坦作为业界知名的3S（RS／GIS／GPS）空间信息软件产品及行业解决方案提供者,获得了市场一定的认可,即便在全球经济危机的影响下仍然保有稳定的市场份额和强大的生命力。其相关产品已经在教育,科研,环保,铁路,交通,民航,电力,水利,航空航天,测绘,公安,国防,国土资源调查,城市规划,土地规划利用,林业资源管理,地下管网管理,     

计算机漏洞安全检测应用技术

计算机技术飞速发展,为人们的生活带来了极大的便利,计算机时代已经全面到来,当今社会是互联网+的时代,计算机被广泛的应用到人们生活的各个领域,但是计算机技术的应用与普及,对于人类生活而言却是一把双刃剑,计算机技术的飞速发展,在为人们的生活提供更多便利条件的同时,计算机漏洞安全也是当今人类社会面临的一个重要问题,计算机病毒会迅速的产生和传播,致使计算机存在漏洞,用户的个人信息泄漏,使得用户的个人信息和财产安全埋下隐患,前几年的熊猫烧香病毒,迅速传播对于社会造成严重损失,因此如何对计算机加强保护,对于计算机漏洞进行检测,是计算机时代发展的重要课题,本文将对于计算机的安全漏洞、计算机漏洞的艰涩技术、计算机漏洞检测技术的应用等三个方面展开讨论,通过对于计算机漏洞安全检测技术的应用,来降低电脑病毒对于计算机的威胁,保证计算机的安全,避免用户个人信息泄露、重要数据资料丢失,从而保证计算机的使用安全,推动计算机技术的发展.     

HelSweeper: Screw-sweeps of canal surfaces

A tube is a solid bounded by the union of a one-parameter family of circles that may be decomposed into canal-surfaces and planar disks or annuli. A screw-sweep is the region swept by a shape during a screw motion. HelSweeper computes the boundary of a screw-sweep of an arbitrary union of tubes and polyhedra. To do so, it generates a superset of faces, splits them at their intersections, and selects the face portions that form the desired boundary. The novelty of the proposed approach lies in the fact that the faces contributed to this superset by a tube are each a screw-sweeps of a rigid curve (generator), which is the locus of grazing points, and that each grazing point is formulated as the intersection of a circle of the tube with a corresponding screw-plane. Hence, each such face is a one-parameter family of helices, each being the screw-sweep of a grazing point.     

Control of Motion of an Actively Bending Body in Channels with Dry Friction

Mechanics is described and equations are given of the motion of an actively bending homogeneous body of a finite thickness in a channel with dry friction under conditions of a weak bending. Control is suggested of the motion of a body in a sinusoidal channel, which retains a continuous first derivative of the controlling moment and a bounded second derivative. A process is described of the maximization of the speed of motion by control and then by the choice of the best parameters of a channel. Control is also considered of other modes of the motion of a body in the same channel.     

Applying the extended Kalman filter to systems described by nonlinear differential-algebraic equations

This paper describes a method for the state estimation of nonlinear systems described by a class of differential-algebraic equation models using the extended Kalman filter. The method involves the use of a time-varying linearisation of a semi-explicit index one differential-algebraic equation. The estimation technique consists of a simplified extended Kalman filter that is integrated with the differential-algebraic equation model. The paper describes a simulation study using a model of a batch chemical reactor. It also reports a study based on experimental data obtained from a mixing process, where the model of the system is solved using the sequential modular method and the estimation involves a bank of extended Kalman filters.     

Construction of a supermicro sense of force feedback and vision for micro-objects: development of a haptic device

This research aims to develop a combined sense system that uses both the force feedback and visual feedback to establish the shape of microscopic features of a microsample. It is thought that the efficiency of minute procedures would be improved if the operator could obtain a sense of force while using a manipulator. We used a cantilever to touch a minute object and obtain a reaction force from the degree of bending. We made a haptic device which gives a sense of that force to the operator, who can feel the force when a user touches a sample with a cantilever. In addition, when the haptic device is used in simulations, the user can feel a force just as if the user had touched a sample.     

High-Order Accurate Adaptive Kernel Compression Time-Stepping Schemes for Fractional Differential Equations

We present a goal-oriented a posteriori error estimator for finite element approximations of a class of homogenization problems. As a rule, homogenization problems are defined through the coupling of a macroscopic solution and the solution of auxiliary problems. In this work we assume that the homogenized problem is known and that it depends on a finite number of auxiliary problems. The accuracy in the goal functional depends therefore on the discretization error of the macroscopic and the auxiliary solutions. We show that it is possible to compute the error contributions of all solution components separately and use this information to balance the different discretization errors. Additionally, we steer a local mesh refinement for both the macroscopic problem and the auxiliary problems. The high efficiency of this approach is shown by numerical examples. These include the upscaling of a periodic diffusion tensor, the case of a Stokes flow over a porous bed, and the homogenization of a fuel cell model which includes the flow in a gas channel over a porous substrate coupled with a multispecies nonlinear transport equation.     

Vague集向Fuzzy集转化的一种新方法

提出Vague值向Fuzzy值转化的实用方法的定义。针对文献[6]中的一个Vague值向Fuzzy值转化的均值修正法,提出了加权均值修正法,并证明了这种方法同样是Vague值向Fuzzy转化的一种非常实用的方法。     

A superscalar simulation employing poisson distributed stalls

This paper presents a statistical approach to estimating the performance of a superscalar processor. Traditional trace-driven simulators can take a large amount time to conduct a performance evaluation of a machine, especially as the number of instructions increases. The result of this type of simulation is typically tied to the particular trace that was run. Elements such as dependencies, delays, and stalls are all a direct result of the particular trace being run, and can differ from trace to trace. This paper describes a model designed to separate simulation results from a specific trace. Rather than running a trace-driven simulation, a statistical model is employed, more specifically a Poisson distribution, to predict how these types of delay affects performance. Through the use of this statistical model, a performance evaluation can be conducted using a general code model, with specific stall rates, rather than a particular code trace. This model allows simulations to quickly run tens of millions of instructions and evaluate the performance of a particular micro-architecture while at the same time, allowing the flexibility to change the structure of the architecture.     

Branching processes of Petri nets

Summary The notion of a branching process is introduced, as a formalization of an initial part of a run of a Petri net, including nondeterministic choices. This generalizes the notion of a process in a natural way. It is shown that the set of branching processes of a Petri net is a complete lattice, with respect to the natural notion of partial order. The largest element of this lattice is the unfolding of the Petri net.     

The probabilistic orienteering problem

The probabilistic orienteering problem (POP) is defined on a directed graph where a cost is associated with each arc and a prize is associated with each node. Moreover, each node will be available for visit only with a certain probability. A server starts from a fixed origin, has a given budget to visit a subset of nodes, and ends at a fixed destination. In a first stage, a node subset has to be selected and a corresponding a priori path has to be determined such that the server can visit all nodes in the subset and reach the destination without exceeding the budget. The list of available nodes in the subset is then revealed. In a second stage, the server follows the a priori path by skipping the absent nodes. The POP consists in determining a first-stage solution that maximizes the expected profit of the second-stage path, where the expected profit is the difference between the expected total prize and the expected total cost.We discuss the relevance of the problem and formulate it as a linear integer stochastic problem. We develop a branch-and-cut approach for the POP and several matheuristic methods, corresponding to different strategies to reduce the search space of the exact method. Extensive computational tests on instances with up to 100 nodes show the effectiveness of the exact method and the efficiency of the matheuristics in finding high quality solutions in a few minutes. Moreover, we provide an extended analysis on a subset of instances to show the value of explicitly modeling the stochastic information in the problem formulation.