消除溢出问题的精确Baum-Welch算法

Baum-Welch算法是在语音领域中用于HMM(hidden Markov model)模型参数训练的最基本方法之一.但它在多样本训练时存在着严重的上、下溢问题,需要不断地人工介入来调整中间参数.该文提出了一种新的能消除上、下溢问题的Baum-Welch改进算法.该算法不但摆脱了人工介入,保证了计算的精度,而且不会带来过大的计算和存储要求.实验结果表明了这种新算法的有效性.     

关于INTEL96系列单片机中HSO事件的设置

就ＭＣＳ－９６系列单片机中设置ＨＳＯ事件时,若事件的触发时间超过定时器Ｔ１、Ｔ２的溢出间隔的问题进行了讨论,给出了具体的解决方案,对许多文献资料中关于这一问题的论述进行了补充,具有实用意义。     

基于源代码的缓冲区溢出预防技术

基于缓冲区溢出的攻击是一种常见的安全攻击手段,也是目前惟一最重要最常见的安全威胁。在所有的软件安全漏洞中,缓冲区溢出漏洞大约占一半。该文从编程的角度分析了缓冲区溢出攻击,并提出在源代码阶段尽量避免缓冲区溢出的方法。     

Separation of synchronous and asynchronous communication via testing

One of the early results concerning the asynchronous π$\pi$-calculus which significantly contributed to its popularity is the capability of encoding the output prefix of the (choiceless) π$\pi$-calculus in a natural and elegant way. Encodings of this kind were proposed by Honda and Tokoro, by Nestmann and (independently) by Boudol. We investigate whether the above encodings preserve De Nicola and Hennessy’s testing semantics. In this sense, it turns out that, under some general conditions, no encoding of the output prefix is able to preserve the must testing. This negative result is due to (a) the non-atomicity of the sequences of steps which are necessary in the asynchronous π$\pi$-calculus to mimic synchronous communication, and (b) testing semantics’ sensitivity to divergence.     

A reactive GRASP and path relinking for a combined production–distribution problem

An NP-hard production–distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize total cost taking production setups, inventory levels and distribution into account. An integer linear model is proposed as a compact problem specification but it cannot be solved to optimality for large instances. Instead of using a classical two-phase approach (production planning and then route construction for each day), metaheuristics that simultaneously tackle production and routing decisions are developed: a GRASP (greedy randomized adaptive search procedure) and two improved versions using either a reactive mechanism or a path-relinking process. These algorithms are evaluated on 90 randomly generated instances with 50, 100 and 200 customers and 20 periods. The results confirm the interest of integrating production and distribution decisions, compared to classical two-phase methods. Moreover, reaction and path-relinking give better results than the GRASP alone.     

Simplifying the weft hierarchy

We give simple, self-contained proofs of the basic hardness results for the classes W[t]$W[t]$ of the weft hierarchy. We extend these proofs to higher levels of the hierarchy and illuminate the distinctions among its classes. The anti-monotone collapse at W[1,s]$W[1,s]$ and the normalization of weft-t$t$ formulas arise as by-products of the proofs.     

南面沟泵站施工导流的方案比选

泵站施工导流与水文条件、地质条件、交通条件、工程布置和建筑材料等密切相关,常规导流方案一般通过新建临时建筑物来进行导流,利用导流明渠和围堰相结合的方式来保证干场作业,但是新建临时建筑物会增加工程占地与工程投资,对工程的进度造成不利影响。以海南省南面沟泵站为例,提出临时建筑物与永久建筑物相结合的导流方案,与常规方案进行比较,从而选择最佳导流方案。     

河道中在建工程抗洪抢险的关键技术措施

2012年3月上旬,峡江水利枢纽工程遭遇历史罕见早汛,超过了其二期枯水围堰设计导流8 620 m3/s的流量标准。 为此,上级要求必须确保该围堰在11 000 m3/s流量范围内安全过洪。武警水电部队在该围堰抢险过程中科学运用“洪水管理削控洪峰流量、工程措施提高抗洪能力”的抗洪抢险策略,采用了拓展河床过流断面、削减控制洪峰流量、围堰加高加固三项关键技术措施,使该围堰成功抵御了10 600 m3/s洪峰和持续50 h大于8 620 m3/s的超标流量,为河道中在建的类似工程的抗洪抢险提供了宝贵经验。     

拔贡水电站改扩建工程二期施工导流围堰优化施工

文章阐述了拔贡水电站改扩建工程二期施工导流围堰施工优化方案,结合工程实际情况及特点,合理布置,采取有效措施,顺利完成了二期施工导流围堰施工,为二期基坑开挖创造了良好前提条件。