QUESTION ANSWERING USING QUESTION CLASSIFICATION AND DOCUMENT TAGGING

Question answering (QA) is a relatively new area of research. We took the approach of designing a question answering system that is based on question classification and document tagging. Question classification extracts useful information from the question about how to answer the question. Document tagging extracts useful information from the documents, which are used to find the answer to the question. We used different available systems to tag the documents. Our system classifies the questions using manually developed rules. An evaluation of the system is performed using Text REtrieval Conference (TREC) data.     

Selective Recovery of Palladium (II) from Metallurgical Wastewater Using Thiadiazole-Based Chloromethyl Polystyrene-Modified Adsorbent

Selective adsorption of palladium from metallurgical wastewater containing Pt (IV), Rh (III), Ca²⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺, V³⁺, and Ti⁴⁺ has tremendous economic and environmental benefits. In this paper, a novel thiadiazole-based chloromethyl polystyrene-modified adsorbent, viz. 2, 5-bis-polystyrene-1,3,4-thiadiazole (PS-DMTD), was synthesized using chloromethyl polystyrene as the backbone. The experimental results show that PS-DMTD can selectively separate Pd (II) from metallurgical wastewater in a one-step adsorption process. The calculated saturation adsorption capacity of PS-DMTD for Pd (II) was 176.3 mg/g at 25 °C. The separation factors of β_{Pd (II)/M}ⁿ⁺ (Mⁿ⁺: Pt (IV), Rh (III), Ca²⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺, V³⁺, and Ti⁴⁺) were all higher than 1 × 10⁴. FT-IR, XPS, and single-crystal X-ray diffraction showed that the adsorption of Pd (II) to PS-DMTD was primarily through a coordination mechanism. Density functional theory (DFT) calculations revealed that the other base metal ions could not coordinate with the PS-DMTD. Pt (IV) could not be adsorbed to PS-DMTD due to its strong chlorophilicity. Furthermore, Rh (III) existed as a polyhydrate, which inhibited Rh (III) diffusion toward the positively charged absorption sites on the PS-DMTD. These results highlight that PS-DMTD has broad application prospects in the recovery of Pd (II) from metallurgical wastewater.     

对τ-p变换中几个问题的探讨

本文在对τ—p变换原理作了简略介绍的基础上,从理论上详细讨论了τ—p变换中假频和端点效应的形成原理,提出了一整套消除假频和端点效应的方法技术,其中,特别是值得指出的是变速介质中的反假频自适应加权倾斜叠加方法和自动切除技术.通过模型试验资料对各种方法的效果作了对比验证.另外,作者还对τ—p域内动校正问题作了理论分析和模型试验,提出了水平层状介质条件下的动校正公式.这就疏通了直接在τ—p域内进行动校、叠加以及作速度分析的渠道.     

用地震记录预测薄层厚度

经理论模型计算，用时差估算薄层厚度的分辨率在１／８～１／４波长之间。由于川东石炭系是一套含泥质极少、横向分布比较稳定的高速白云岩，上覆地层是阳新统底部的低速泥岩，下伏地层是志留系的大套低速砂质泥岩。这一地层组合使其上下构成良好的反射界面。经数口井合成记录与地震记录对比，符合性很好，且由合成记录上的时差计算的厚度与钻井厚度一致。由此证明，用地震记录上的时差计算厚度（大于调谐厚度）是可行的。     

提高速度分析精度的方法

基于传统的速度分析方法,着重讨论了地层倾角、速度扫描参数及相干性测量给速度分析精度带来的影响。在设计速度扫描间隔△v时,要力求符合扫描精度标准。采用同炮检距道集进行迭代叠加和乘模型系数道叠加,可以提高速度分析的精度。乘模型系数道叠加法较其他方法有更大的优越性,这主要表现在浅中层有效反射的能量更集中、深层的“平臂效应”减少、便于计算等方面。     

一种新的速度分析方法叠后倾角扫描法

叠后倾角扫描法是一种新的速度分析技术。其原理是先对一组连续的CDP道集用一组速度曲线作动校叠加形成不同叠加速度的叠加段,再对各叠加段分别作倾角扫描叠加,根据倾斜叠加能量的大小确定其地层倾角,然后用所求出的倾角值对原来各叠加段作一次时变的倾角校正叠加,最后根据叠加能量大小确定速度值。由于本方法两次运用叠加的统计效应,改善了用以分析确定速度信息的资料品质,并且在求速度的过程中减弱了地层倾角的影响,所以与传统速度分析方法相比较,速度分析精度有了提高。尤其是在原始资料质量差、地层倾角大的地区,效果更为显著。     

储层模式识别技术

在一个剖面段上，先作预处理，压制噪声，各类校正，去掉与目的层无关的影响；然后进行特征拾取，计算出能反映其含油气性的ｎ个特征量，组成ｎ维特征矢量；最后由分类器计算出对这个ｎ维持征矢量进行分类的判别函数的值。若值大于零为Ｉ类（与油气层有关），若值小于零为Ⅱ类（与非含油气层有关）。本文介绍了分类器的设计和特征拾取方法，并给出了模型正演记录和两个实例。     

TOPIC DETECTION OF UNRESTRICTED TEXTS: APPROACHES AND EVALUATIONS

ABSTRACT

Topic detection and tracking refers to automatic techniques for locating topically related cohesive paragraphs in a stream of text. Most documents are about more than one subject, but many Natural Language Processing (NLP) and Information Retrieval (IR) techniques implicitly assume documents have just one topic. Even in the presence of a single topic within a document, the document may address multiple subtopics and various aspects of the primary topic. Hence, dividing documents into topically coherent units and discovering their topic might have many uses. We describe new clues that account for the topic of grouping of contiguous portions of the text. Those clues are based on general lexical resources, which make them applicable to unrestricted texts, and can have many uses such as helping users find answers to general questions in an information search task, or in question/answering systems, or in text summarization. We devise an algorithm for identifying these clues, and we report on the performance of these clues, as well as the improvements suggested by our experiments.     

Exploring the Interface Between Formal and Informal Real Estate Markets in Facilitating Legally Binding Transactions in Zambian Cities

Informality is the order of the day in most cities in the Global South. This paper explored the puzzle whereby informal activities result in legally binding real estate transactions in the city of Kitwe in Zambia. The paper conceptualises the “market” from an institutional economics perspective as a system to coordinate human activities and not merely as the interaction of supply and demand. Using evidence from Chimwemwe, a formal municipal township in the city of Kitwe, and a questionnaire survey amongst registered and unregistered real estate agents, the study found that most “market transactions” in low-cost formal settlements are facilitated through social networks of friends, relatives, and neighbours and through informal agents, and minimally through formal agents. These transactions are then legally registered at the Council Deeds Registry for legal transfer. Despite the existence of the Estate Agents Act of 2000, and the establishment of the Zambia Institute of Estate Agents (ZIEA), the study found that most informal agents have problems complying with the registration provision, thus leaving them to operate illegally. Nonetheless, these informal agents provide a service in low-income settlements through procedures which mirror formal ones, resulting in legally recognised and binding transactions and at cost commensurate to the incomes of their clients. However, the negative traits exhibited by some informal agents cannot be overlooked, thus it is necessary to re-examine the law to understand what is preventing informal agents from complying with this provision on registration.