Keigo Kimura

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This paper describes a new architecture for high-resolution digital PWM (DPWM) generator used in digitally-controlled DC-DC converters, PWM time resolution is determined by the difference between two (or more) gate delays, while that of conventional DPWM circuits is determined by gate delay itself. The proposed DPWM circuit can achieve fine time resolution(More)
Nonnegative Matrix Factorization (NMF) is a popular technique in a variety of fields due to its component-based representation with physical interpretablity. NMF finds a nonnegative hidden structures as oblique bases and coefficients. Recently, Orthogonal NMF (ONMF), imposing an orthogonal constraint into NMF, has been gathering a great deal of attention.(More)
PURPOSE To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). DESIGN Laboratory research. PARTICIPANTS Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. METHODS The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0%(More)
PURPOSE BRAF mutations are common in sporadic colorectal cancers (CRCs) with a DNA mismatch repair (MMR) deficiency that results from promoter methylation of hMLH1, whereas KRAS mutations are common in MMR proficient CRCs associated with promoter methylation of MGMT. The aim of this study was to further investigate the link between genetic alterations in(More)
OBJECTIVE Vascular calcification is a feature of arteriosclerosis and in hemodialysis (HD) patients it may be severe, even at a relatively young age, and is closely related to the overall prognosis. We used the aortic calcification area index (ACAI), derived from the aortic calcification index (ACI), to evaluate and analyze the risk factors for abdominal(More)
Recently orthogonal nonnegative matrix factorization (ONMF), imposing an orthogonal constraint into NMF, has been attracting a great deal of attention. ONMF is more appropriate than standard NMF for a clustering task because the constrained matrix can be considered as an indicator matrix. Several iterative ONMF algorithms have been proposed, but they suffer(More)
This report concerns the first case in Japan of interstitial nephritis induced by mesalazine, a new therapeutic agent for inflammatory bowel disease, such as ulcerative colitis. Twenty-two cases have already been reported in other countries. The patient, a 27-year-old woman, was treated with mesalazine for her ulcerative colitis at another hospital. At the(More)
Nonnegative Tensor Factorization (NTF) has become a popular tool for extracting informative patterns from tensor data. However, NTF has high computational cost both in space and in time, mostly in iterative calculation of the gradient. In this paper, we consider variable selection to reduce the cost, assuming sparsity of the factor matrices. In fact, it is(More)
Lately, multi-label classification (MLC) problems have drawn a lot of attention in a wide range of fields including medical, web, and entertainment. The scale and the diversity of MLC problems is much larger than single-label classification problems. Especially we have to face all possible combinations of labels. To solve MLC problems more efficiently, we(More)