没有最深，只有更深

“很多时候,你们的题目很新颖,但是仔细一看,会让人觉得内容挖掘得不够深入、不够实际。”这是某位CIO为CIO INSIGHT提出的中肯意见。“深挖”,是杂志的立命之本,因为无法和报纸、网络、电视、广播拼速度、广度,所以必须在文章内容的深度上下功夫。可惜的是,即便懂得这个道理,也没有哪本杂志能够完全避免由于这样或那样的原因造成的“浅尝即止”。     

没有想不到，只有找不到

现在的搜索引擎绝对能让你抓狂,关键词、服务、楗索、信息源……不管专业不专业,取巧不取巧,绝大多数都是以文字的机器检索为基础的,单调无比。即便像Google这样的搜索引擎提供了个性化的外观和服务,但是其本质还是一个搜索框。凭什么搜索引擎就要一板一眼？凭什么要我自己处心积虑地思考关键词？……不是我不爽,而是我非常不爽。那怎么办？换搜索引擎呗!没有想不到,只有找不到。     

没有“5”,没有副标题，只有真实世界规则的《鬼屋魔影》

当Atari和Eden Games公布它的时候，一切看起来都是那么美妙——新式样的谜题、与环境的高度互动以及令人惊叹的光源．两年时间已经过去了，Eden Games看上去还在埋头苦干。我们可以确定的是．他们只做了两件事：一是去掉了那个叫做“濒死调查”（Near Death Investigation）的副标题，     

IPSec，SSL没有最好只有更好

VPN(Virtual Private Networ, 虚拟专用网)是利用公共网络资源为窗户组建专用网的一种技术,安通过对网络数据进行封包和加密传输,在公网上传输么有数据,以达到私有网络的安全级别。 IPSec (IP Security) 在过去几年来一直是受欢迎的技术,提供站点间(例如:分支办公室到总部) 以及远程访问的安全联机。今天,全球各地许多厂家提供这种解决方案。 2003年初,Gartner的一份报告称,未来全球SSL (Securesocket Layer、安全套接层协议)VPN的市场增长速度将达170％以上,在所有的安全产品中增速排名第一。那么,行业及企业用户在选型和部署VPN时,该如何选择呢? 融合了哪些技术特色的VPN方案是最适合用户的? 不同的VPN部署策略将给用户的安全带来哪些问题? 本期《高端导刊-安全》介绍权威厂商Netscreen、Nokia、方正数码、联想的观点和方案,帮助用户正确地认识和选择适合自身应用需求的VPN方案。     

李绍远：没有魔法，只有基本功

ERP从来不缺少概念,也不缺少喧嚣,但是在李绍远那里,更多的是默默地修为和耕耘,这正应了一句老话“吃虫的鸟儿不叫唤”。     

没有最BT，只有更BT的验证码

验证码最主要的功能,就是防止机器人注册。一般说来,我们通常都会遇到扭曲的英文或数字。不过,有些验证码实在是BT到一种境界。比如下面这个验证码,为了证明你不是机器人,请选择三个最热辣的MM,简直可爱、销魂得无以复加。小编暗想,如果我们PCD论坛也改用这样的注册验证码,估计99％的同学都要疯掉的……更多BT的验证码,请大家移步到上面的帖子欣赏。     

没有最强的职业，只有最强的玩家

在伟大的英雄成吉思汗长眠之后,亚洲版图上轮番上演混乱的讨伐和频繁的战争。为了成就同天子可汗一样的霸主英雄,《成吉思汗Ⅱ》推出了四大天赋玩法。而随着四大天赋玩法逐一亮相,天赋养成被越来越多的玩家所称赞和接受,《成吉思汗Ⅱ》即将迎来自己崭新的“天赋时代”。     

只有想不到，没有买不到 USB转换设备知多少

USB接口方便易用的特性众所周知．但采用其它接口的各种设备仍然有用武之地,用户难以放弃,于是各种USB转换线／转换器应运而生．最常见的莫过于USB-PS/2转换器,有了它就可以在电脑的USB接口上使用传统的PS／2鼠标。现在就让我们来认识这些各式各样的USB转换设备．说不定其中就有你能用到的。     

“锤子手机”产品没有故事，只有品质

自从罗永浩召开发布会之后,很多人问如何看待这场发布会以及Smartisan T1。借用罗永浩的话,我们“少废话,先看东西。”尽量抛开粉丝争议和故事情怀来看这款产品。     

A Property Tester for Tree-Likeness of Quartet Topologies

Property testing is a rapid growing field in theoretical computer science. It considers the following task: given a function f over a domain D, a property ℘ and a parameter 0<ε<1, by examining function values of f over o(|D|) elements in D, determine whether f satisfies ℘ or differs from any one which satisfies ℘ in at least ε|D| elements. An algorithm that fulfills this task is called a property tester. We focus on tree-likeness of quartet topologies, which is a combinatorial property originating from evolutionary tree construction. The input function is f _Q , which assigns one of the three possible topologies for every quartet over an n-taxon set S. We say that f _Q satisfies tree-likeness if there exists an evolutionary tree T whose induced quartet topologies coincide with f _Q . In this paper, we prove the existence of a set of quartet topologies of error number at least c((n) || 4)c{n\choose 4} for some constant c>0, and present the first property tester for tree-likeness of quartet topologies. Our property tester makes at most O(n ³/ε) queries, and is of one-sided error and non-adaptive.     

A Fast Quartet tree heuristic for hierarchical clustering

The Minimum Quartet Tree Cost problem is to construct an optimal weight tree from the weighted quartet topologies on n objects, where optimality means that the summed weight of the embedded quartet topologies is optimal (so it can be the case that the optimal tree embeds all quartets as nonoptimal topologies). We present a Monte Carlo heuristic, based on randomized hill-climbing, for approximating the optimal weight tree, given the quartet topology weights. The method repeatedly transforms a dendrogram, with all objects involved as leaves, achieving a monotonic approximation to the exact single globally optimal tree. The problem and the solution heuristic has been extensively used for general hierarchical clustering of nontree-like (non-phylogeny) data in various domains and across domains with heterogeneous data. We also present a greatly improved heuristic, reducing the running time by a factor of order a thousand to ten thousand. All this is implemented and available, as part of the CompLearn package. We compare performance and running time of the original and improved versions with those of UPGMA, BioNJ, and NJ, as implemented in the SplitsTree package on genomic data for which the latter are optimized.     

New Fixed-Parameter Algorithms for the Minimum Quartet Inconsistency Problem

Let S be a set of n taxa. Given a parameter k and a set of quartet topologies Q over S such that there is exactly one topology for every subset of four taxa, the parameterized Minimum Quartet Inconsistency (MQI) problem is to decide whether we can find an evolutionary tree inducing a set of quartet topologies that differs from the given set in at most k quartet topologies. The best fixed-parameter algorithm devised so far for the parameterized MQI problem runs in time O(4 ^k n+n ⁴). In this paper, first we present an O(3.0446 ^k n+n ⁴) fixed-parameter algorithm and an O(2.0162 ^k n ³+n ⁵) fixed-parameter algorithm for the parameterized MQI problem. Finally, we give an O ^*((1+ε) ^k ) fixed-parameter algorithm, where ε>0 is an arbitrarily small constant.     

一种基于Quartet Puzzling和邻接法的进化树构建算法

最大似然法是目前较准确的一种进化树构建方法,但是其时间复杂度非常高.在实际应用中,用分治策略实现最大似然法的Quartet Puzzling(QP)得到了人们的关注.它首先估计Quartet拓扑结构集合Q,然后利用重组技术将Q中的信息合并到一起构成一个包含所有序列的进化树.研究表明,QP的准确性不像人们所期望的那样高.如何快速有效地将Q所包含的信息融合在一起仍然是QP所面-临的一个问题.为了提高QP,结合邻接法提出一种新的进化树构建方法QPNJ.理论上,QPNJ与QP具有相同的时间复杂度.通过模拟实验将QPNJ与QP以及目前流行的进化树构建方法进行了比较.结果表明,QPNJ比QP和邻接法更准确,并且其性能不依赖于模型树的结构,从而证明了QPNJ的有效性.     

Computing the Quartet Distance between Evolutionary Trees in Time O( n log n)

Evolutionary trees describing the relationship for a set of species are central in evolutionary biology, and quantifying differences between evolutionary trees is therefore an important task. The quartet distance is a distance measure between trees previously proposed by Estabrook, McMorris, and Meacham. The quartet distance between two unrooted evolutionary trees is the number of quartet topology differences between the two trees, where a quartet topology is the topological subtree induced by four species. In this paper we present an algorithm for computing the quartet distance between two unrooted evolutionary trees of n species, where all internal nodes have degree three, in time O(n log n. The previous best algorithm for the problem uses time O(n ²).     

Computing the Quartet Distance between Evolutionary Trees in Time O ( n log n )

Evolutionary trees describing the relationship for a set of species are central in evolutionary biology, and quantifying differences between evolutionary trees is therefore an important task. The quartet distance is a distance measure between trees previously proposed by Estabrook, McMorris, and Meacham. The quartet distance between two unrooted evolutionary trees is the number of quartet topology differences between the two trees, where a quartet topology is the topological subtree induced by four species. In this paper we present an algorithm for computing the quartet distance between two unrooted evolutionary trees of n species, where all internal nodes have degree three, in time O(n log n. The previous best algorithm for the problem uses time O(n ²).     

Effective solution of certain problems of theory of schedulings of nets

Cybernetics and Systems Analysis -     

变电站一次设备喷涂PRTV用量的分析

对国网宁夏电力检修公司宁安运维站近2年来一次设备喷涂PRTV用量的统计数据进行分析整理,得出各类一次设备按照标准要求喷涂PRTV时的用量估算值,并针对现存作业中存在的问题,提出相应解决方案。     

新型煤泥浮选机液位传感装置的研制

介绍了一种性能良好的新型浮球式煤浆液位传感装置。该装置利用浮球随着煤浆液位的变化而带动连杆作上下运动,通过机械装置将液位的变化转变成角位移传感器的轴的角度变化,分析角位移传感器输出信号可得到煤泥液位信息。经测试该传感装置各项指标达到了设计要求。该新型煤泥浮选机液位传感装置具有良好的动、静态特性,可以在选煤厂推广应用。