Global Optimization for Advertisement Selection in Sponsored Search

Advertisement (ad) selection plays an important role in sponsored search, since it is an upstream component and will heavily influence the effectiveness of the subsequent auction mechanism. However, mo...     

双曲线法在沉降预测中的应用分析

简要介绍了常用的软土路基沉降预测方法，对双曲线图解法的使用范围及实测数据点的选取进行了分析，并使用LINEST函数对其进行线性回归，将其用于具体工程实例，取得了理想的效果。     

PS版毛面层技术

胶印PS版具有支持体和感光层，通常在感光层表面还涂有一层毛面层，内含均匀分布的细小固体颗粒。印刷底片置于PS版上曝光时，必须进行减压抽真空，以去除两者之间的空气间隔，保证底片和PS版能够平整贴在一起；毛面层可显著提高抽真空效果。本文阐述PS版毛面层的功能、主要成分及其制备工艺等。     

关于电子技术教材中的符号问题

本文分析了目前在电子技术教材中使用文字符号和图形符号方面存在的问题，以及产生这些问题的原因，并提出了建议。由于“国标”符号的规定过于复杂，导致符号功能的退化，不便于在教学中使用。目前国外大多数电子技术教材和书刊中仍使用国际流行符号，而国内教材中的符号比较混乱。为便于教学，也便于国际交流，笔者建议国内出版的教材也可以采用国际流行符号，以改变目前同一本教材中符号不一致的混乱情况。     

Maximizing revenue with allocation of multiple advertisements on a Web banner

The problem addressed in this paper is the allocation of multiple advertisements on a Web banner, in order to maximize the revenue of the allocated advertisements. It is essentially a two-dimensional, single, orthogonal, knapsack problem, applied to pixel advertisement. As this problem is known to be NP-hard, and due to the temporal constraints that Web applications need to fulfill, we propose several heuristic algorithms for generating allocation patterns. The heuristic algorithms presented in this paper are the left justified algorithm, the orthogonal algorithm, the GRASP constructive algorithm, and the greedy stripping algorithm. We set out an experimental design using standard banner sizes, and primary and secondary sorting criteria for the set of advertisements. We run two simulations, the first simulation compares the heuristics with an optimal solution found using brute force search, and the second simulation compares the heuristic algorithms to gain a better insight into their performance. Finding a suitable pattern generating algorithm is a trade-off between effectiveness and efficiency. Results indicate that allocating advertisements with the orthogonal algorithm is the most effective. In contrast, allocating advertisements using the greedy stripping algorithm is the most efficient. Furthermore, the best settings per algorithm for each banner size are given.     

美容广告的语篇模式初探

结合实例分析认为,很多推销和宣传化妆品(包括美容技术)的广告都采用"问题-解决办法"语篇模式,由"情景"、"问题"、"解决办法"和"评估"4个部分构成.其中,"问题"和"解决办法"是"必需成分";"情景"和"评估"则可以不出现.     

基于数字高程模型的河网提取及子流域生成

提出新的从DEM直接提取河网与划分子流域的方法(AEDNM)。该方法与以往方法的不同之处在于不再对DEM进行填洼处理，而是结合图论与水文学的思想，从流域的出口直接向上游搜索，通过图的遍历来确定流向，使全流域形成一个有向无环图，这样提取的河网可以保证是连续的，同实际河网误差很小。根据河网划分的子流域大小也基本均匀，能够满足水文模型模拟的需求。经过黄河、泾河与白河流域的算例验证，表明该法简单可行。     

网络广告中图像的生成成因

作为社会环境的组成部分,文化无疑是对广告传播产生影响的重要因素,它同时也影响到作为广告信息传播的主要载体——图像。本文通过挖掘当代文化的深层次内涵、受众的审美要求以及图像自身的变化,结合数字技术发展状况,对网络广告中的图像在文化全球化背景下的生成成因进行了初步探讨。     

Three Dimensional Simulation of Ion Thruster Plume-Spacecraft Interaction Based on a Graphic Processor Unit

Based on the three-dimensional particle-in-cell (PIC) method and Compute Unified Device Architecture (CUDA), a parallel particle simulation code combined with a graphic processor unit (GPU) has been developed for the simulation of charge-exchange (CEX) xenon ions in the plume of an ion thruster. Using the proposed technique, the potential and CEX plasma distribution are calculated for the ion thruster plume surrounding the DS1 spacecraft at different thrust levels. The simulation results are in good agreement with measured CEX ion parameters reported in literature, and the GPU’s results are equal to a CPU’s. Compared with a single CPU Intel Core 2 E6300, 16-processor GPU NVIDIA GeForce 9400 GT indicates a speedup factor of 3.6 when the total macro particle number is 1.1×10 6 . The simulation results also reveal how the back flow CEX plasma affects the spacecraft floating potential, which indicates that the plume of the ion thruster is indeed able to alleviate the extreme negative floating potentials of spacecraft in geosynchronous orbit.