3,440 research outputs found
Concept-based retrival fo ChIN
No full text随着Internet的快速发展，文献检索技术作为帮助用户获取信息的手段正在发挥越来越重要的的作用。传统的基于关键字匹配的检索和全文检索技术有时已经不能完全满足用户的要求。基于概念的文献检索区别于传统的检索方法，以查询条件与文档之间的概念匹配作为文献命中的依据，力求达到更高的查全率和查准率。隐含语义检索（LSI）作为基于概念的文献检索方法的一种，是一种智能的检索方法。它允许用户使用自然语言的查询条件，查询依据不是查询条件和文档在文字上的匹配，而是在概念上的相近。它的核心算法采用对文档一词条矩阵进行截断的奇异值分解（SVD）。本论文对隐含语义检索方法进行了研究，并提供了一种实现的途径，在Internet化学资源导航系统（ChIN）中建立了隐含语义检索系统。本论文详细描述了在ChIN中建立隐含语义检索系统的过程：从ChIN管理数据库中提取出要检索的信息并进行处理，并构造文档一词条矩阵，采用快速算法对文档一词条矩阵进行SVD分解，根据用户通过Intexnet提交的查询条件和SVD分解结果实施查询，通过Web页面输出查询结果。本论文介绍了LSI算法实施中的关键步骤，并根据Ch则系统的特点选择了适当实现方案，使得本系统成为一个完整的、实用性很强的检索系统。作为ChIN中原有的基于关系数据库的关键字检索和全文检索方法的辅助检索手段，LSI为用户获得需要的文档提供了便利。本论文还对LS I算法中的参数选择进行了研究
Walsh-LS CDMA systems
No full textDue to the existence of an Interference-Free-Window (IFW) or Zero-Correlation-Zone (ZCZ), a Large Area Synchronous-CDMA (LAS-CDMA) system can have a much higher system capacity and spectral efficiency than traditional CDMA. The more multi-path spreads falling in the ZCZ the greater the reduction of Inter-symbol Interference (ISI) and multiple access interference (MAI). In this paper an introduction to a CDMA forward link concept employing loosely synchronous (LS) codes and Walsh codes is presented. The LS codes are used for distinguishing cells and sectors while the individual users are separated using Walsh codes. The resulting correlation functions exhibit a ZCZ. The proposed design allows for a ZCZ that can be more easily and dynamically adjusted to cover the majority or all of the multi-path spread. The use of Walsh to separate the users places less stress on finding large family sizes of LS codes. This paper is organised as follows, a section on construction and properties of Walsh-LS spreading codes, a section on the system simulation model and the simulation results followed lastly by a conclusion
Voice And Valence-altering Operations In Falam Chin: A Role And Reference Grammar Approach
No full textThis dissertation describes and analyzes voice and valence-altering operations in Falam Chin, a Tibeto-Burman language of Burma. The data is explained within the framework of Role and Reference Grammar (RRG), which supplies several key concepts particularly useful for generalizing the behavior of the Falam Chin operations. The first is RRG\u27s system of semantic decomposition, based on Dowty (1979), which is used to formulate each predicate\u27s underlying logical structure (LS). Second is the concept of macroroles, generalized semantic roles actor and undergoer, which are assigned to the arguments of a predicate according to a hierarchy of LS positions. M-transitivity refers to the number of macroroles assigned to a given predicate (Van Valin & LaPolla 1997; Van Valin 2005).Within this framework, each of the primary voice and valence-altering operations of Falam Chin are shown to be lexical operations which affect the underlying LS and/or macrorole assignment of the base predicate. Causatives and applicatives are valence-raising operations which fuse two LSs by means of a lexical rule, such that their arguments are treated as the arguments of a single predicate. On the other hand, reflexives, reciprocals, and middles assign coreferentiality to two arguments of the base predicate, after which they lower M-transitivity by joining the macroroles of the two coreferential arguments into a single macrorole. Finally, antipassives lower M-transitivity by blocking macrorole assignment to the lower-ranking argument of the base predicate.While Falam Chin displays both dependent-marking and head-marking characteristics, this dissertation argues that it is a fundamentally head-marking language. As is characteristic of head-marking languages, Falam Chin\u27s NPs are in semantic apposition to its cross-reference pronominals, which are the true core arguments. In light of this, a number of unusual features of Falam Chin\u27s voice and valence-altering operations are revealed to be natural results of its head-marking makeup. Furthermore, as claimed by Nichols (1986), head-marking languages tend to downplay syntactic distinctions in favor of semantic and pragmatic ones, a characteristic evident in Falam Chin\u27s preference for lexical operations with semantic and pragmatic functions
Computational Mechanics for Shape Optimization and Airplane Bombing Based on OpenFOAM and LS-DYNA Software
No full textIn this dissertation, two problems are studied by computational mechanics. The first problem is the development and application of open-source software OpenFOAM to solve a coupled system from shape optimization on a time-dependent changing domain to minimize a cost functional. Previously, researchers have treated this problem in 2D space, but here the author will extend the computation to 3D space. She will use the finite volume methods and OpenFOAM to build time-varying domains for optimization.
The second problem is about computational forensics. The author will discuss some photographic evidence, introduce mathematical modeling and do computational modeling regarding this particular Daallo Airlines bombing case, in which only a small amount of explosives was used. Mathematical and computer modeling of viscoplasticity, fracture and explosion by LS-DYNA will be used to study this problem and we computed on the supercomputer at Texas A&M University’s High Performance Research Computing Center. All of the numerical results of airplane bombing can be seen in the many video animations we made from the post-processed supercomputer results. The associated physical phenomena will also be interpreted
Author Attributions in Medieval Text Collections: An Exploration
No full textThis article examines the role and function of author attributions in multi-text manuscripts containing Dutch, English, French or German short verse narratives. The findings represent one strand of the investigations undertaken by the cross-European project ‘The Dynamics of the Medieval Manuscript’, which analysed the dissemination of short verse narratives and the principles of organisation underlying the compilation of text collections. Whilst short verse narratives are more commonly disseminated anonymously, there are manuscripts in which authorship is repeatedly attributed to a text or corpus. Through six case studies, this article explores medieval concepts of authorship and how they relate to constructions of authority, whether regarding an empirical figure or a literary construction. In addition, it looks at how authorship plays a role in manuscript compilation, and at the effects of attributions (by author and/or compiler) on reception. The case studies include manuscripts from the thirteenth to fifteenth centuries, produced in a range of social and cultural contexts, and featuring some of the most important European authors of short verse narratives: Rutebeuf, Baudouin de Condé, Der Striker, Konrad von Würzberg, Willem of Hildegaersberch, and Geoffrey Chaucer. The preliminary findings contribute to our understanding of author attributions in text collections from across northern Europe and point towards future lines of enquiry into the role of authorship in medieval textual dissemination
The etiology of esophageal cancer in high- and low- risk areas of Jiangsu province, China
No full text [Background]Esophageal cancer (EC) remains one of the most common and fatal malignancies worldwide. The geographic variation in EC occurrence is striking, and China is an area with one of the highest incidences of EC. A number of epidemiological studies have been conducted toward EC in the past decades, results suggested that tobacco smoking, alcohol drinking, unhealthy dietary factors and chronic injuries of the esophageal mucosa are important in the development of this disease. Genetic polymorphisms in enzymes involved in metabolism of carcinogens may also influence individual susceptibility. However, the effects of major lifestyle and hereditary risk factors on the development of EC remain poorly understood in China. Moreover, little attention has been paid to the etiological heterogeneity between similar areas with great risk gradient. [Methods]From 2003 to 2007, a large population-based case-control study of EC has been conducted in a selected high-risk area and a selected low-risk area of Jiangsu Province, one of the highest cancer incidence areas in China. In total, 1,520 cases and 3,879 controls were recruited. In this thesis, we evaluated the role of major lifestyle factors such as tobacco smoking, alcohol drinking and dietary factors, as well as inherited determinants including family history of cancer and genetic polymorphisms of alcohol-metabolizing related genes on the risk of EC. In addition, we investigated how much of the risk gradient between two areas could be explained by variation in the distributions of major risk factors. [Results] Tobacco smoking and alcohol drinking moderately increased the risk of EC, while the positive associations were only found among men but not among women. Dietary factors were observed to play important roles in the development of EC. Specific dietary habits i.e., fast eating speed, and hot eating and/or drinking substantially elevated EC risk and could explain more than 20% of EC cases each. High intake of salty foods and fried foods, low consumption of raw garlic were also observed to increase the risk of EC. In addition to environmental and lifestyle factors, we confirmed that a positive family history can significantly increase EC risk, and found the inheritance may modify the effect of some unhealthy lifestyles. Moreover, we further explored the relationship between EC and single nucleotide polymorphismsof ADH1B, ADH1C and ALDH2 genes. Results showed that the slow metabolizing ADH1B G allele, ADH1C G allele and ALDH2 A allele significantly increased EC risk among moderate-to-heavy alcohol drinkers, and a significant interaction was observed between ALDH2 gene and alcohol consumption. Lastly, we found that more than 60% of EC cases could be attributable to major lifestyle risk factors in the study population; furthermore, dissimilar distribution of several lifestyle factors, together with variations of hereditary factors may be largely responsible for the incidence difference between two study areas. [Conclusion]The findings in this thesis confirm that unhealthy lifestyles including smoking, alcohol drinking and some dietary factors are the predominant risk factors of EC in China, and a large proportion of incidence difference between regions at varying risk could be attributed to the different prevalence of lifestyle factors. As most of the identified risk factors are modifiable, these could be translated into risk reduction prevention programs in China, and a substantial proportion of new EC cases are expected to be prevented by eliminating or avoiding these risk factors in the population. </p
Batch Bayesian Learning of Large-Scale LS-SVMs Based on Low-rank Tensor Networks
No full textLeast Squares Support Vector Machines (LS-SVMs) are state-of-the-art learning algorithms that have been widely used for pattern recognition. The solution for an LS-SVM is found by solving a system of linear equations, which involves the computational complexity of O(N^3). When datasets get larger, solving LS-SVM problems with standard methods becomes burdensome or even unfeasible. The Tensor Train (TT) decomposition provides an approach to representing data in highly compressed formats without loss of accuracy. By converting vectors and matrices in the TT format, the storage and computational requirements can be greatly reduced. In this thesis, we develop a Bayesian learning method in the TT format to solve large-scale LS-SVM problems, which involves the computation of a matrix inverse. This method allows us to include the information we know about the model parameters in the prior distribution. As a result, we are able to obtain a probability distribution of the parameters, which enables us to construct confidence levels of the predictions. In the numerical experiment, we show that the developed method performs competitively with the current methods.Mechanical Engineering | Systems and Contro
BSN: Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg
No full textThe light curve analyses and orbital period variations for two contact binary stars, LS Del and V997 Cyg, are presented in this work which was conducted in the frame of the Binary Systems of South and North project. Ground-based photometric observations were performed at two observatories in France. We used the Transiting Exoplanet Survey Satellite (TESS) data for extracting times of minima and light curve analysis of the target systems. The O − C diagram for both systems displays a parabolic trend. LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt = 7.20 × 10−08 days yr−1 and dP/dt = 2.54 × 10−08 days yr−1, respectively. Therefore, it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt = –1.96 × 10−7M⊙ yr−1 for the LS Del system, and dM/dt =–3.83 × 10−7M⊙ yr−1 for V997 Cyg. The parameters of a third possible object in the system are also considered. The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves. The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima. The mass ratio, fill-out factor, and star temperature all indicate that both systems are contact binary types in this investigation. Two methods were applied to estimate the absolute parameters of the systems: one method relied on the parallax of Gaia DR3, and the other used a P − M relationship. The positions of the systems are also depicted on the M − L, M − R, q − Lratio, and logMtot - logJ0 diagrams. We recommend that further observations and investigations be done on the existence of a fourth body in this system.Scientific Research Projects Coordination Unit of Erciyes University [FBA-2022-11737]; NASA Explorer ProgramThis manuscript was prepared by the BSN project (https://bsnp.info/). This project was supported by the Scientific Research Projects Coordination Unit of Erciyes University (project number FBA-2022-11737). We have made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC). This work includes data from the TESS mission observations. Funding for the TESS mission is provided by the NASA Explorer Program. We thank Ehsan Paki for his comments on the orbital period variation section
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