Eigenvector space model to capture features of documents

Eigenvectors are a special set of vectors associated with a linear system of equations. Because of the special property of eigenvector, it has been used a lot for computer vision area. When the eigenvector is applied to information retrieval field, it is possible to obtain properties of documents data corpus. To capture properties of given documents, this paper conducted simple experiments to prove the eigenvector is also possible to use in document analysis. For the experiment, we use short abstract document of Wikipedia provided by DBpedia as a document corpus. To build an original square matrix, the most popular method named tf-idf measurement will be used. After calculating the eigenvectors of original matrix, each vector will be plotted into 3D graph to find what the eigenvector means in document processing.

The dS swampland conjecture with the electroweak symmetry and QCD chiral symmetry breaking

The dS swampland conjecture $|\nabla V|/V \geq c$, where $c$ is presumed to be a positive constant of order unity, implies that the dark energy density of our Universe can not be a cosmological constant, but mostly the potential energy of an evolving quintessence scalar field. As the dark energy includes the effects of the electroweak symmetry breaking and the QCD chiral symmetry breaking, if the dS swampland conjecture is applicable for the low energy quintessence potential, it can be applied for the Higgs and pion potential also. On the other hand, the Higgs and pion potential has the well-known dS extrema, and applying the dS swampland conjecture to those dS extrema may provide stringent constraints on the viable quintessence, as well as on the conjecture itself. We examine this issue and find that the pion dS extremum at $\cos(\pi_0/f_\pi)=-1$ implies $c\lesssim {\cal O}(10^{-2}-10^{-5})$ for $arbitrary$ form of the quintessence potential and couplings, where the weaker bound ($10^{-2}$) is available $only$ for a specific type of quintessence whose couplings respect the equivalence principle, while the stronger bound ($10^{-5}$) applies for generic quintessence violating the equivalence principle. We also discuss the possibility to relax this bound with an additional scalar field, e.g. a light modulus which has a runaway behavior at the pion dS extremum. We argue that such possibility is severely constrained by a variety of observational constraints which do not leave a room to significantly relax the bound. We make a similar analysis for the Higgs dS extremum at $H=0$, which results in a weaker bound on $c$.Comment: 25 pages, 2 figures, v3: we updated the detailed numerical value for the fifth force constraint from full two loop calculations in (13

Zoom-SVD: Fast and Memory Efficient Method for Extracting Key Patterns in an Arbitrary Time Range

Given multiple time series data, how can we efficiently find latent patterns in an arbitrary time range? Singular value decomposition (SVD) is a crucial tool to discover hidden factors in multiple time series data, and has been used in many data mining applications including dimensionality reduction, principal component analysis, recommender systems, etc. Along with its static version, incremental SVD has been used to deal with multiple semi infinite time series data and to identify patterns of the data. However, existing SVD methods for the multiple time series data analysis do not provide functionality for detecting patterns of data in an arbitrary time range: standard SVD requires data for all intervals corresponding to a time range query, and incremental SVD does not consider an arbitrary time range. In this paper, we propose Zoom-SVD, a fast and memory efficient method for finding latent factors of time series data in an arbitrary time range. Zoom-SVD incrementally compresses multiple time series data block by block to reduce the space cost in storage phase, and efficiently computes singular value decomposition (SVD) for a given time range query in query phase by carefully stitching stored SVD results. Through extensive experiments, we demonstrate that Zoom-SVD is up to 15x faster, and requires 15x less space than existing methods. Our case study shows that Zoom-SVD is useful for capturing past time ranges whose patterns are similar to a query time range.Comment: 10 pages, 2018 ACM Conference on Information and Knowledge Management (CIKM 2018

Contributing to Quality of Life: A New Outcome Variable for Information Technology in Ubiquitous Computing Environments

The rapid spread of technological innovations like mobile data services (MDS) has made ubiquitous computing a fact of everyday life for many people. We need therefore to understand the contribution of ubiquitous computing to overall quality of life. This study proposes a theoretical model that connects user satisfaction (a traditional outcome variable of IT) with contributions to quality of life (a new outcome variable for ubiquitous computing) in the domain of MDS. The reliability of the outcome variables and the validity of the proposed model were tested through three empirical studies in Korea. Study results indicate that user satisfaction with MDS affected the contribution of MDS to quality of life in eleven subordinate domains, and these contributions in turn influenced the overall contribution of MDS to quality of life. The paper ends with a discussion of the implications and limitations of the study results

mtCO1-based population structure and genetic diversity of Pacific oyster *Crassostrea gigas* populations acquired from two farms in South Korea

Since the early 1990s in South Korea, climatic and anthropogenic factors have incurred the reduction of the wild seeds of the Pacific oyster, Crassostrea gigas, which raised concerns about losing genetic diversity and accelerating genetic deterioration. We assessed the genetic diversity of C. gigas populations from two farms (Tongyeong and Gadeokdo) on the southern coast, where about 80% of the cultivated oysters in Korea are produced. Tongyeong showed slightly higher diversity than Gadeokdo, but both populations had a similar genetic structure characterized by low nucleotide diversity. Comparative haplotype analyses provided data supporting genetic features of the populations that include (1) weak genotype-locality relationship, (2) low levels of gene flow between populations, and (3) possible seasonal fluctuation of genetic variation within a population. Furthermore, the highly alike haplotype network patterns were observed between the wild and farm populations as well as among the populations in neighboring countries, which suggests that the genetic structure is conserved between wild and hatchery populations, and geographic proximity has minimal influence on the genetic composition