《计算之书》中“elchataym”算法探源

《计算之书》中的"elchataym"算法是求解线性问题精确解的一种一般性算法,作者斐波那契指出此算法源于阿拉伯,除此没有更多关于其来源的叙述.通过对早期阿拉伯数学家萨马瓦尔《代数珍宝》阿拉伯文献的解读,将他所述阿拉伯"双试错法"与《计算之书》中的"elchataym"算法从算法公式、算法满足条件及算法证明等方面进行详细比较,发现二者可能是同源的.     

公益数字图书馆建设中存在的问题刍议

从著作权法入手,着力分析了技术保护措施和许可协议在我国公益性数字图书馆建设中所存在的问题,并提出了解决的思路.     

Universal Distributed Estimation Scheme for a Bandwidth Constrained Ad Hoc Sensor Network

This paper describes a distributed estimation scheme (DES) for a bandwidth constrained ad hoc sensor network.The DES is universal in the sense that operations on all sensors are identical and independent of noise distribution.The scheme requires each sensor to transmit just a 1-bit message per observation.Simulation results show that the scheme achieves much better mean-squares error (MSE) performance than the simplified isotropic universal DES and even outperforms the isotropic universal DES which requires more than twice the bandwidth of this scheme.     

A NAM Representation Method for Data Compression of Binary Images

A representation method using the non-symmetry and anti-packing model (NAM) for data compression of binary images is presented.The NAM representation algorithm is compared with the popular linear quadtree and run length encoding algorithms.Theoretical and experimental results show that the algorithm has a higher compression ratio for both lossy and lossless cases of binary images and better reconstructed quality for the lossy case.     

卷取张力转动惯量补偿控制

为提高带钢卷取过程中张力控制的稳定性,利用自适应控制对PID控制器参数进行转动惯量补偿,结果表明,自适应控制系统能够提高张力控制的稳定性.     

旅游管理专业伦理教育体系研究

旅游伦理教育存在教育缺失、实践教育不足、旅游企业无伦理意识、旅游伦理教育没有推广到学生中和企业中等问题。通过构建＂三位三联一体模式＂教育体系,实现理论、实践、学生自主学习相结合,促进旅游伦理教育发展。     

Applying File Information to Block-Level Content Addressable Storage

Content addressable storage (CAS) is a promising technology for improving storage efficiency as well as access throughput.Currently,many CAS products are implemented on the block level,which results in loss of file information.Thus,some sophisticated optimizations cannot be achieved,such as accurate fileprefetching.This paper presents a file-aware block-level storage system combined with the CAS function.In contrast with some existing file-level CAS,this system is transparent to upper-level applications,including the operating system and the file system.These features are achieved by using smart-disk technologies to help the storage system to learn the file-system layout.A prototype was implemented on an open-source virtual machine (VM) with the guest operating system being Windows XP.Tests show that this combination significantly reduces the size of the VM image file and improves the storage performance by discarding unused blocks and using a simple file-level prefetching strategy.     

补偿收缩混凝土的合理应用

根据我国补偿收缩混凝土在实际施工中发现的问题,通过结合技术规范的修订和产品标准,总结出混凝土膨胀剂的正确添加,可供相关技术人员参考.     

公路路基工程常见病害及防治技术

公路路基工程是一个专业的系统工程,牵涉的点多面广,一条公路可能穿越多种地质结构,沿线地基和土壤情况多变,填筑材料数量巨大、种类繁多,需要使用的机械设备多种多样,施工工艺不一而足,再加上工程实施期限较长、气候复杂多变等因素都对工程质量产生重要影响,容易造成病害.文章就常见的病害及防治措施提出意见.