Masaya Murata

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We investigated properties of cells affecting their optical trapping force and successfully established a novel cell separation method based on the combined use of optical trapping force and microfluidics on a microchip. Our investigations reveal that the morphology, size, light absorption, and refractive index of cells are important factors affecting their(More)
This paper reports our methods and experimental results for two TRECVID 2012 tasks of instance search and multimedia event detection. For the instance search, we applied the BM25(Best Match 25) method, the state-of-the-art ranking function in the field of text retrieval, to the video retrieval task. Our BM25 features the following three factors: (i) the(More)
Users of text retrieval systems input only a few keywords or sometimes just one keyword to the systems even if they had complex information needs. Due to the lack of query keywords, it becomes hard to return relevant search results that satisfy the demands of each user. Because digital documents, in contrast to queries, are generally composed of many kinds(More)
Information needs expressed by using the same query for a search engine might be totally different, whether on week days or weekends, or during the day or at night. For queries having no temporal changes in search intentions, the same search results ranking may be returned regardless of the time, but for those with temporal changes the ranking must be(More)
A Kalman filter (KF) is state-of-the-art for estimating states of linear-Gaussian state-space models. The KF selects an expectation of a posterior probability density function of state and the expectation is an analytic solution for minimizing the square estimation error. The estimate of KF is therefore optimal, however, simultaneously inherits the problem(More)
This paper reports our method and experimental result on the TRECVID 2014[1] instance search task. Since 2012, we have been applying BM25 (Best Match 25), i.e., the state-of-the-art probabilistic information retrieval method in the field of text retrieval, to the instance search task. The standard BM25 uses the well-known Inverse Document Frequency (IDF) as(More)
Kalman filter (KF) design is well established for perfectly known linear system and observation models. Realworld phenomena, however, have significant associated uncertainties, and the tuning of the KF is not so straightforward for tackling them. In this paper, we present a method of designing a robust filter for nonlinear systems with model parameter(More)