Mining Term Association Rules for Global Query Expansion: A Case Study with Topic 202 from TREC4

The sudden growth of the World Wide Web and its unprecedented popularity as a de facto global digital library exemplified both the strengths and weaknesses of the Information Retrieval techniques used by popular search engines. Most queries are short and incomplete attempts to describe or characterize the possible documents relevant to the query. It seems then natural to try and expand the queries with additional terms, which are semantically and/or statistically associated with the original query terms. In this paper we are looking at the mining of associations between terms for the exploration of the terminology of a corpus as well as for the automatic expansion of queries. The technique we use for the discovery of the associations is association rules mining [Agrawal 96]. The technique we propose is more flexible than previous techniques based on term co-occurrence since it takes into account not only the co-occurrence frequency but also the confidence and direction of the association rules. Our preliminary experiment results show we can get benefit from this novel technique

Lack of association between the CALM1 core promoter polymorphism (-16C/T) and susceptibility to knee osteoarthritis in a Chinese Han population

<p>Abstract</p> <p>Background</p> <p><it>CALM1 </it>gene encodes calmodulin (CaM), an important and ubiquitous eukaryotic Ca²⁺-binding protein. Several studies have indicated that a deficient CaM function is likely to be involved in the pathogenesis of osteoarthritis (OA). Using a convincing genome-wide association study, a Japanese group has recently demonstrated a genetic association between the <it>CALM1 </it>core promoter polymorphism (-16C/T transition SNP, rs12885713) and OA susceptibility. However, the subsequent association studies failed to provide consistent results in OA patients of differently selected populations. The present study is to evaluate the association of the -16C/T polymorphism with knee OA in a Chinese Han population.</p> <p>Methods</p> <p>A case-control association study was conducted. The polymorphism was genotyped in 183 patients who had primary symptomatic knee OA with radiographic confirmation and in 210 matched controls. Allelic and genotypic frequencies were compared between patients and control subjects.</p> <p>Results</p> <p>No significant difference was detected in genotype or allele distribution between knee OA and control groups (all <it>P </it>> 0.05). The association was also negative even after stratification by sex. Furthermore, no association between the -16C/T SNP genotype and the clinical variables age, sex, BMI (body mass index) and K/L (Kellgren/Lawrence) score was observed in OA patients.</p> <p>Conclusion</p> <p>The present study suggests that the CALM1 core promoter polymorphism -16C/T is not a risk factor for knee OA susceptibility in the Chinese Han population. Further studies are needed to give a global view of this polymorphism in pathogenesis of OA.</p

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Modelling Temporal Semantics of Data

Recently, many temporal query languages, such as TCAL and TQuelhave been proposed for temporal databases. However, there are still some limitations such as the inadequacy on operating data with temporal elements and handling the semantics of time ‘NOW ’ in these temporal query languages. After defining a new temporal relational algebra, in this paper we build a tuple calculus language based on gap-interval for temporal databases. This tuple calculus is designed to support time query, non-time query, and general temporal query. In particular, the semantics of time ‘NOW ’ is well implemented in this language; and the first temporal-normalform of relations under the extended operators is closure in our temporal query language

A compact broadband antenna for ultra high frequency and L band on 5G new radio base stations

Abstract A simple method is proposed for the realisation of compact dual‐polarised antennas. The aperture area of a dual‐polarised dipole antenna can be reduced by half by surrounding the antenna with a square loop. Based on the method, a broadband compact dual‐polarised antenna is developed. The broadband dual‐polarised antenna consists of two ±45°‐polarised dipoles surrounded by a square loop and fed by two orthogonal broadband baluns. A resonance at a sfrequency (fLr = 0.7 GHz) is created by the square loop, leading to a compact size of about λLr/4 × λLr/4, where λLr is the wavelength in free space at fLr. Another resonance at a higher frequency (fHr = 1.5 GHz) is generated by etching open slots on the ±45°‐polarised dipoles. A combination of the lower‐frequency and the higher‐frequency resonances results in a broadband operation. Simulation and experimental results show that the compact dual‐polarised antenna achieves an impedance bandwidth of 75% (0.69–1.52 GHz) for return loss > 15 dB with stable radiation patterns, which is potential to be used for 5G new radio base‐station applications

Study on Deformation Law of Deep Foundation Pit with the Top-Down Method and Its Influence on Adjacent Subway Tunnel

Based on a long-term comprehensive instrumentation program, the performance of an excavation pit constructed by the top-down method in downtown Kunming was extensively examined. The measured excavation responses included the deflections of diaphragm wall, vertical column movement, slab axial force, building settlement caused by ground deformation, and the influence of pit excavation on the adjacent subway tunnel. This paper analyses the monitoring data of the existing construction stage. Based on the analyses on the data of field and numerical simulation, the following major findings were obtained: (1) the relationship between the measured maximum wall deflection, δhm, and excavation depth, H, in this study is δhm=0.06%H∼0.27%H, which is quite different compared with the relationship of soft-soil pit δhm=0.02%H∼1.2%H, but closer to the normalized curve of rock-socketed pile δhm=0.01%H∼0.45%H and rock-socketed diaphragm wall δhm=0.031%H∼0.129%H. (2) The relationship between the maximum settlement of column (δp) and excavation depth (H) is δp=−0.09%∼0.04%H. The maximum distortion between the diaphragm wall and the column is less than 1/500 of the limit range proposed by Bjerrum. (3) The impact range caused by excavation is about 3.8 times the maximum excavation depth. The ground settlement around the foundation pit is groove type, and the maximum settlement point is located at 2.7 times the maximum excavation depth. (4) The excavation of the foundation pit leads to the maximum vertical settlement of 2 mm and maximum horizontal displacement of 5.2 mm in the subway tunnel; the maximum change of axial force and bending moment are 8.8 kN (the vertical direction) and 6.4 kN·m/m (the horizontal direction), respectively

Missing is Useful: Missing Values in Cost-Sensitive Decision Trees

Abstract. Many real-world datasets for machine learning and data mining contain missing values, and much previous research regards it as a problem, and attempts to impute missing values before training and testing. In this paper, we study this issue in cost-sensitive learning that considers both test costs and misclassification costs. If some attributes (tests) are too expensive in obtaining their values, it would be more cost-effective to miss out their values, similar to skipping expensive and risky tests (missing values) in patient diagnosis (classification). That is, “missing is useful ” as missing values actually reduces the total cost of tests and misclassifications, and therefore, it is not meaningful to impute their values. We discuss and compare several strategies that utilize only known values and that “missing is useful ” for cost reduction in cost-sensitive decision tree learning