Investigation on How to Improve Latent Semantic Analysis Performance

Latent Semantic Analysis (LSA) is a matching technique capable of recognizing the semantic relationships of data that ordinary techniques such as string matching cannot. This is especially valuable for data integration applications, like those of Acxiom, where data items are usually related by context, rather than in a literal match. Even though it has been shown that LSA is 30% more effective in finding and ranking relevant pieces of information than existing string-by-string matching techniques (Deerwester et al., 1990; Dumais, 1995), the performance of the LSA seems to be affected by the presence of shared words, or “noise”, in data. The objective of this research is to study the influence of noise on the LSA performance quantitatively and analytically, which provides understanding for the following researches to develop a noise-filter method used to improve LSA performance. Our research shows that shared terms degrade the performance of LSA for matching queries to documents from the same category, and result in increased misclassification. In addition, share terms change the document that best matches the query

The Molecular Mechanism of Progesterone Receptor in Regulating Gene Expression in Mouse Granulosa Cells during Ovulation

The process of ovulation is critical for successful fertilisation and pregnancy. Of utmost importance is the progesterone receptor (PGR), which regulates various biological processes preceding pregnancy including ovulation, oviductal oocyte/embryo transportation and embryo implantation. How PGR can achieve divergent reproductive roles is still poorly understood. This thesis aims to explore the molecular mechanisms that allow for highly specialised PGR ovulatory functions through describing the PGR cistrome and transcriptome in mouse peri-ovulatory granulosa cells when PGR is highly induced and active. In addition, the relationship between PGR and other transcription factors, especially RUNX1, as well as isoform-specific actions were also determined. As PGR acts through direct binding to the PGR response element (PRE), differences in PGR chromatin targets can influence PGR actions. Characterisation of the PGR cistrome using chromatin immunoprecipitation – sequencing (ChIP-seq) showed striking distinctions in preferential PGR targets in peri-ovulatory granulosa cells compared to the uterus. Granulosa PGR favourably interacted with transcriptionally active promoters and had few mutual chromatin targets with uterine PGR. Interestingly, motif analysis of PGR peaks identified specific patterns in the degree of PRE occupancy and the enrichment of distinct non-canonical motifs, suggesting that PGR interacts with other transcription factors in a context-specific manner. Motif analysis of PGR peaks in granulosa cells implied a number of potential protein partners such as the JUN/FOS, LRH1, and RUNX families. The physical interaction of these proteins with PGR in mouse peri-ovulatory granulosa cells was confirmed through proximity ligation assay. Among these, RUNX was a granulosa-specific factor and thus potentially important in granulosa-specific PGR roles. RUNX1 displayed context-specific chromatin binding properties as shown through RUNX1 ChIP-seq of mouse foetal and adult granulosa cells before and after the LH surge. In peri-ovulatory granulosa cells, PGR/RUNX1 interaction was specifically hCG-induced, RUNX1 shared mutual targets and non-canonical binding motifs with PGR that resulted in the regulation of mutual ovulatory genes. This indicates a close interplay between PGR and RUNX1 in granulosa cells during ovulation, likely in conjunction with other modulators. The PGR-A and PGR-B isoforms play distinct roles in different biological contexts, with PGR-A being prominent in peri-ovulatory granulosa cells. To further assess the specific roles of PGR-A and PGR-B during ovulation, transcriptomes of peri-ovulatory granulosa cells from mice lacking both isoforms (PGRKO), PGR-A (AKO) or PGR-B (BKO) were obtained through RNA-seq. More than 600 differentially expressed genes were identified in PGRKO and AKO with few identified in BKO. Mutual PGR/RUNX1 direct binding was important in the regulation of these genes. PGRKO and AKO transcriptomes shared nearly half of their genes with little similarities with the BKO transcriptome. The transcriptomic data supports the key physiological roles of PGR-A in ovulation. Altogether, this study provides the first description of the PGR cistrome, interactome and transcriptome in granulosa cells. A unique cooperation between PGR, especially PGR-A, and specific transcription factors, especially RUNX1, in a mutual transcription complex leads to the specification of PGR ovulatory action in granulosa cells. Such understanding in tissue-specific PGR actions is crucial for the development of novel contraceptives targeting ovulation.Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 202

Low regularity integrators for semilinear parabolic equations with maximum bound principles

This paper is concerned with conditionally structure-preserving, low regularity time integration methods for a class of semilinear parabolic equations of Allen-Cahn type. Important properties of such equations include maximum bound principle (MBP) and energy dissipation law; for the former, that means the absolute value of the solution is pointwisely bounded for all the time by some constant imposed by appropriate initial and boundary conditions. The model equation is first discretized in space by the central finite difference, then by iteratively using Duhamel's formula, first- and second-order low regularity integrators (LRIs) are constructed for time discretization of the semi-discrete system. The proposed LRI schemes are proved to preserve the MBP and the energy stability in the discrete sense. Furthermore, their temporal error estimates are also successfully derived under a low regularity requirement that the exact solution of the semi-discrete problem is only assumed to be continuous in time. Numerical results show that the proposed LRI schemes are more accurate and have better convergence rates than classic exponential time differencing schemes, especially when the interfacial parameter approaches zero.Comment: 24 page

Consumer-based Brand value: A study on Foreign Banks in Ho Chi Minh City Market

The article presents an empirical study to discover consumers’ perception on foreign banks’ brand value which is said as one of key drivers for business success. The study is aimed at assisting brand managers to track their brand value and hence to improve their product and service quality. The conceptual model is founded on a consumer-based approach to brand value. To validate the model, a survey of 183 interviewees was carried out in four popular foreign banks in Ho Chi Minh City: Citibank, HSBC, ANZ and Standard Chartered (SCB). The collected data was tested and analyzed by Exploratory Factor Analysis. The study reveals that Brand Knowledge, Brand Differentiation, Brand Relevance and Brand Esteem correlate closely to each other and have a strong affect to Consumer-based Brand Value. The findings are discussed and the implications for banks’ management are presented

Cerebrospinal fluid lactate concentration to distinguish bacterial from aseptic meningitis: a systemic review and meta-analysis

ABSTRACT: INTRODUCTION: Making a differential diagnosis between bacterial meningitis and aseptic meningitis is a critical clinical problem. The utility of a cerebrospinal fluid (CSF) lactate assay for this purpose has been debated and is not yet routinely clinically performed. To adequately evaluate this assay, a systematic review and meta-analysis of studies of the CSF lactate concentration as a marker for both bacterial meningitis and aseptic meningitis was performed. METHODS: Electronic searches in PubMed, Scopus, the MEDION database and Cochrane Library were conducted to identify relevant articles published before March 2009. A manual search of reference lists from selected articles was also conducted. Two reviewers independently selected relevant articles and extracted data on study characteristics, quality and accuracy. RESULTS: Twenty-five articles were identified that met the eligibility criteria. Diagnostic odds ratios were considerably homogenous (Chi-square p = 0.1009, I2 = 27.6%), and the homogeneity was further confirmed by a Galbraith plot and meta-regression analysis using several covariates. The symmetrical summary receiver-operator characteristic curve (SROC), fitted using the Moses-Shapiro-Littenberg method, was positioned near the upper left corner of the SROC curve. The Q value and area under the curve were 0.9451 and 0.9840, respectively, indicating excellent accuracy. The diagnostic accuracy of the CSF lactate concentration was higher than those of other four conventional markers (CSF glucose, CSF/plasma glucose quotient, CSF protein, and CSF total number of leukocytes) using a head to head meta-analysis of the 25 included studies. CONCLUSIONS: To distinguish bacterial meningitis from aseptic meningitis, CSF lactate is a good single indicator and a better marker compared to other conventional markers

Ecological factors associated with dengue fever in a central highlands Province, Vietnam

<p>Abstract</p> <p>Background</p> <p>Dengue is a leading cause of severe illness and hospitalization in Vietnam. This study sought to elucidate the linkage between climate factors, mosquito indices and dengue incidence.</p> <p>Methods</p> <p>Monthly data on dengue cases and mosquito larval indices were ascertained between 2004 and 2008 in the Dak Lak province (Vietnam). Temperature, sunshine, rainfall and humidity were also recorded as monthly averages. The association between these ecological factors and dengue was assessed by the Poisson regression model with adjustment for seasonality.</p> <p>Results</p> <p>During the study period, 3,502 cases of dengue fever were reported. Approximately 72% of cases were reported from July to October. After adjusting for seasonality, the incidence of dengue fever was significantly associated with the following factors: higher household index (risk ratio [RR]: 1.66; 95% confidence interval [CI]: 1.62-1.70 per 5% increase), higher container index (RR: 1.78; 95% CI: 1.73-1.83 per 5% increase), and higher Breteau index (RR: 1.57; 95% CI: 1.53-1.60 per 5 unit increase). The risk of dengue was also associated with elevated temperature (RR: 1.39; 95% CI: 1.25-1.55 per 2°C increase), higher humidity (RR: 1.59; 95% CI: 1.51-1.67 per 5% increase), and higher rainfall (RR: 1.13; 95% CI: 1.21-1.74 per 50 mm increase). The risk of dengue was inversely associated with duration of sunshine, the number of dengue cases being lower as the sunshine increases (RR: 0.76; 95% CI: 0.73-0.79 per 50 hours increase).</p> <p>Conclusions</p> <p>These data suggest that indices of mosquito and climate factors are main determinants of dengue fever in Vietnam. This finding suggests that the global climate change will likely increase the burden of dengue fever infection in Vietnam, and that intensified surveillance and control of mosquito during high temperature and rainfall seasons may be an important strategy for containing the burden of dengue fever.</p

A Survey on Intrusion Detection Systems for Fog and Cloud Computing

The rapid advancement of internet technologies has dramatically increased the number of connected devices. This has created a huge attack surface that requires the deployment of effective and practical countermeasures to protect network infrastructures from the harm that cyber-attacks can cause. Hence, there is an absolute need to differentiate boundaries in personal information and cloud and fog computing globally and the adoption of specific information security policies and regulations. The goal of the security policy and framework for cloud and fog computing is to protect the end-users and their information, reduce task-based operations, aid in compliance, and create standards for expected user actions, all of which are based on the use of established rules for cloud computing. Moreover, intrusion detection systems are widely adopted solutions to monitor and analyze network traffic and detect anomalies that can help identify ongoing adversarial activities, trigger alerts, and automatically block traffic from hostile sources. This survey paper analyzes factors, including the application of technologies and techniques, which can enable the deployment of security policy on fog and cloud computing successfully. The paper focuses on a Software-as-a-Service (SaaS) and intrusion detection, which provides an effective and resilient system structure for users and organizations. Our survey aims to provide a framework for a cloud and fog computing security policy, while addressing the required security tools, policies, and services, particularly for cloud and fog environments for organizational adoption. While developing the essential linkage between requirements, legal aspects, analyzing techniques and systems to reduce intrusion detection, we recommend the strategies for cloud and fog computing security policies. The paper develops structured guidelines for ways in which organizations can adopt and audit the security of their systems as security is an essential component of their systems and presents an agile current state-of-the-art review of intrusion detection systems and their principles. Functionalities and techniques for developing these defense mechanisms are considered, along with concrete products utilized in operational systems. Finally, we discuss evaluation criteria and open-ended challenges in this area