2004年国际土壤分类会议会讯

20 0 4年国际土壤分类会议于 8月 3～ 8日在俄罗斯的彼得罗扎沃茨克 (Petrozavodsk)召开 ,来自 2 5个国家的80多名土壤发生与分类方面的专家学者参加了会议。会议分两个阶段 ,8月 3～ 5日是室内报告和讨论会议 ,8月 6～ 9日是野外考察 ,对当地土壤进行分类与命名的讨论。这次会议的第一焦点议题是国际土壤参比基础 (WRB)。现任WRB研究组织主席 ,匈牙利的E .Michi博士介绍了WRB的最新进展和未来的目标 ,即使全世界的土壤类型可以在统一的分类标准下分类命名 ,便于全球土壤对比和国际土壤学交流。前任WRB研究组织主席 ,比利时的J .Deck…     

土壤胶膜的研究进展

土壤胶膜是土壤中普遍存在的形成物,其性质与整个土体有较大的变异和不同,对土壤的物质流和能量流、生产力和植物营养以及土壤质量等有重要影响。本文从土壤胶膜的成因、分类、微形态特征、物质组成及其对土壤性质的影响,土壤胶膜与土壤发生与分类、古气候等的关系,探讨了土壤胶膜的研究进展,并展望了以后可能的研究趋势。     

关于"中国土壤系统分类中基层分类研究”的思路

中国土壤系统分类中的基层分类研究的重点是通过选择分异特性和恰当地划分分异特性区间来建立分类指标体系.分异特性应是易于鉴别的对土壤生产力有重要影响的相对稳定的土壤性质;以使土壤分类便于应用于土壤调查,更好地服务于土地评价和规划.研究变量和因变量的定量化关系或土壤性质与土地生产力的定量化关系是准确划分分异特性区间的有效方法.基层分类最好采用检索方法,以求分类的唯一性.连续命名法可以明确表达分类单元的属性.     

德国土壤科学的研究进展

本文通过访问德国前土壤学会主席以及有关文献的查对、研究,介绍了德国土壤科学的主要研究进展,包括德国土壤科学的起源、国家与国际合作、土壤发生学研究、土壤制图与分类、土壤化学与矿物学、土壤物理和生态系统研究等方面的代表性人物与主要研究进展,希望能对我国同行有些启发和借鉴作用。     

以中国土壤系统分类为基础的土壤参比

为了土壤信息交流、知识共享 ,作者首先阐述了与世界土壤分类发展相伴随的中国土壤系统分类的发展 ,进而对中国土壤系统分类与美国土壤分类和WRB方案进行了参比 ,然后着重讨论了它与土壤发生分类之间的参比。今后拟建立土壤参比信息系统以实现计算机自动参比     

柳新国家复垦示范区充填复垦土壤性质及其分类建议

研究了徐州柳新采煤塌陷地充填复垦土壤的pH值和全氮全磷以及有效钾的的性质,并对复垦土壤的分类提出建议.结果表明,该区充填复垦土壤受地下水碱性影响严重;复垦土壤养分中氮和磷含量受影响较大;土壤养分变化受种植作物影响最大,其次是复垦时间长短;充填物性质在短期内对表层土壤性质无明显影响.建议在系统分类中增加复垦表层,扩充人为新成土亚纲的内涵,增设复垦人为新成土土类.     

数值分类在关中地区土壤分类中的应用

选取关中地区12个土壤剖面的15个理化指标,应用主成分分析方法和聚类分析方法对土壤进行了数值分类。研究结果表明,前4个主成分的累计贡献率达到86.41%,取阈值T=4.0,供试12个剖面划分为3类,不同类群之间土壤特性差异明显,类群内部土壤特性相似。数值分类结果与系统分类结果比较,虽然个别土壤的类别出现较大差异,但分类结果基本一致,说明数值分类应用于关中地区土壤分类是切实可行的。     

安徽省沿淮地区几种主要土壤诊断特性和系统分类研究

本文对安徽省沿淮地区的黄棕壤、黄褐土、水稻土、砂姜黑土、潮土和石灰土等六种主要土壤的典型剖面进行系统研究,按《中国土壤系统分类(修订方案)》确定了各土壤剖面具有的诊断层和诊断特性,进行了分类检索,得出了这六种典型土壤剖面在中国土壤系统分类中所属的分类单元,并与现有发生学分类进行了参比。典型剖面研究结果表明:这些土壤分别被划归铁质湿润淋溶土土类、粘磐湿润淋溶土土类、简育水耕人为土土类、淡色潮湿雏形土土类、简育潮湿变性土土类、钙质湿润淋溶土土类。     

大豆主要性状间的灰色关联度分析

为推广应用中国土壤系统分类 ,本文对自然地理野外实习基地—河北省秦皇岛市石门寨区域的土壤进行系统分类研究。结果如下 :土壤诊断层有淡薄表层、水耕表层、雏形层、水耕氧化还原层、粘化层 ,诊断特性有砂质沉积物岩性特征、石质接触面、半干润土壤水分状况、湿润土壤水分状况、人为滞水土壤水分状况、氧化还原特征、冷性土壤温度状况、温性土壤温度状况 ,土壤类型归属为人为土纲、淋溶土纲、雏形土纲和新成土纲。并与原土壤地理发生分类进行参比及总结地理分布规律     

《土壤通报》征稿简则

《土壤通报》是由中国科协主管、中国土壤学会主办和沈阳农业大学承办、科学出版社出版的土壤科学学术期刊。本刊主要刊登土壤科学及与之相关的学术论文、研究简报和文献综述等文章,内容包括土壤发生与分类、土壤地理与土壤调查、土地评价与管理、土壤质量与生态环境、土地利用与改良、土壤化学与土壤物理、植     

An analysis of two-parent recombinations for real-valued chromosomes in an infinite population

This paper concerns recombinations which produce offspring from two parents. We assume an infinite population and regard recombinations as transformations of stochastic variables represented as chromosomes. We then formalize recombinations with the probability density functions of stochastic variables represented as the parameters and describe the change of the probability density functions of chromosomes before and after recombination. Our formalization includes various proposed recombinations, such as multi-point, uniform, and linear crossover, as well as BLX-alpha. We also derive certain properties of the operators, such as diversification and decorrelation.     

Linux进程调度算法分析

在Linux系统中,进程作为实体自始至终运行在系统之中,进程使用系统的资源,而进程的调度更是影响系统的性能:进程响应时间尽可能快,后台进程的吞吐量尽可能高,进程"饿死"现象尽可能避免,低优先级和高优先级进程需要尽可能调和.本文从Linux 2.4.0内核角度分析影响进程调度的各个因素和调度处理流程,以及在SMP(Symmetric Multi Processing)的进程调度处理.     

网络拓扑自动发现系统设计与实现

摘要：设计基于SNMP和其它协议的网络拓扑发现算法,实现三层交换机和路由器为网关的网络拓扑的快速发现,尽可能地发现完整的网络,且对网络带来的额外负栽和开销尽可能小。     

计划体系在ERP系统中的作用分析

该文介绍了计划体系在ERP系统中地位、作用以及计划体系在ERP系统设计实施过程中常遇缺陷对常遇问题进行了分析,并提出解决方案。阐述了计划体系在ERP的核心地位,以及MPS,MRP核心计划在整个计划体系的作用以及运作模式,最后总结了ERP实施过程中的难点提出了几点解决方案。     

An information theory consideration of a design of test input signals†

A problem of determining optimal periodic test input signals for estimating weighting functions of continuous-time systems is considered by an information theory approach. Under appropriate assumptions, the amount of information provided by the measurements in a period is calculated in terms of the corresponding periodic test input signals. By taking the amount of information as a criterion function, the existence of optimal test input signals and the condition for optimality are studied under energy constraint. It is shown that, in the case of observing sampled outputs, an input signal of as small auto-correlation as possible and, at the same time, of as largo energy as possible is optimal, while, in the case of observing outputs continuously, an input signal of as flat a spectrum as possible and, at the same time, of as large energy as possible is optimal. As an example, the optimality of an M-sequence signal is examined.     

Planar split dual gate MOSFET

A new planar split dual gate （PSDG） MOSFET device, its characteristics and experimental results, as well as the three dimensional device simulations, are reported here for the first time. Both theoretical calculation and 3D simulation, as well as the experiment data, show that the two independent split dual gates can provide dynamical control of the device characteristics, such as threshold voltage （Vt） and sub-threshold swing （SS）, as well as the device saturated current. The PSDG MOSFET transistor leakage current （loft） can be reduced as much as 78% of the traditional single gate MOSFET. The PSDG is fabricated and fully compatible with our conventional 0.18 μm logic process flow.     

Simultaneous External and Internal Stabilization for Continuous and Discrete-Time Critically Unstable Linear Systems with Saturating Actuators

The issues arising in hybrid or simultaneous external as well as internal stabilization of linear systems with saturating actuators are considered. Four different stabilization problems are studied. Roughly, these problems are (1) simultaneous semi-global external as well as semi-global internal stabilization, (2) simultaneous semi-global external as well as global internal stabilization, (3) simultaneous global external as well as semi-global internal stabilization, and (4) simultaneous global external as well as global internal stabilization. As evident from the literature, the requirement of internal stabilization alone either in the global or semi-global sense demands that the linear part of the given system be (a) stabilizable, and (b) has all its poles in the closed left half complex plane for continuous-time systems while it has all its poles inside and/or on the unit circle for discrete-time systems. This implies that the posed simultaneous stabilization problems are solvable at best only under the conditions (a) and (b). Under such conditions, we construct here explicit state as well as measurement feedback controllers for all the four problems in the case of continuous-time systems, and for the problems (1), (2) and (4) in the case of discrete-time systems. The design methodologies used to construct appropriate feedback laws are based on by now familiar low-gain and low-and-high gain design concepts or certain scheduled versions of them.     

Wearable computing: toward humanistic intelligence

Over the past 20 years, wearable computing has emerged as the perfect tool for embodying humanistic intelligence (HI). HI is intelligence that arises when a human is part of the feedback loop of a computational process in which the human and computer are inextricably intertwined. It is common in the field of human-computer interaction to think of the human and computer as separate entities. (indeed, the term "HCI" emphasizes this separateness by treating the human and computer as different entities that interact.) However, in HI theory, we prefer not to think of the wearer and the computer with its associated I/O apparatus as separate entities. Instead, we regard the computer as a second brain and its sensory modalities as additional senses, in which synthetic synesthesia merges with the wearer's senses. When a wearable computer functions in a successful embodiment of HI, the computer uses the human's mind and body as one of its peripherals, just as the human uses the computer as a peripheral. This reciprocal relationship is at the heart of HI.     

Modified subset sum heuristics for bin packing

We analyze the worst-case ratio of natural variations of the so-called subset sum heuristic for the bin packing problem, which proceeds by filling one bin at a time, each as much as possible. Namely, we consider the variation in which the largest remaining item is packed in the current bin, and then the remaining capacity is filled as much as possible, as well as the variation in which all items larger than half the capacity are first packed in separate bins, and then the remaining capacity is filled as much as possible. For both variants, we show a nontrivial upper bound of 13/9 on the worst-case ratio, also discussing lower bounds on this ratio.     

融入Universum学习的度量学习算法

度量学习通过更真实的刻画样本之间的距离,来提高分类和聚类的精度。GMML（Geometric Mean Metric Learning）在学习度量矩阵[A]时,使得在该度量下同类点之间的距离尽可能小,不同类点之间的距离尽可能大。GMML用来学习的训练样本均为目标类数据,而对于现实存在的为数众多的同领域非目标类数据,即Universum数据并未加以利用,不免造成信息的浪费,针对此,提出一种新的度量学习算法--融入Universum学习的GMML（U-GMML）。U-GMML期望得到一个新的度量矩阵[A],使得同类点之间的距离尽可能小,不同类点之间的距离尽可能大,且Universum数据与目标类数据的距离尽可能大,从而使得所学习的度量矩阵[A]更有利于分类。真实数据集上的实验结果验证了该算法的有效性。