著者

川合 隆嗣 Takashi Kawai

雑誌

人文論究 (ISSN:02866773)

巻号頁・発行日

vol.60, no.3, pp.113-125, 2010-12-10

著者

Kenji YOKOI Katsumi WATANABE Ryo KATO Takashi KAWAI Tadashi SATO Takashi YAMAZAKI Hitoshi YAMAGATA

出版者

Japan Society of Kansei Engineering

雑誌

KANSEI Engineering International (ISSN:13451928)

巻号頁・発行日

vol.6, no.2, pp.13-18, 2006 (Released:2010-06-28)

参考文献数

24

被引用文献数

3 5

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In this study, we applied a gaze-contingent window method to measure the spatial distribution of visual attention while playing an action video game. The peripheral visual field of a player was restricted to an area around the gaze by masks with various spatial extents. The quantitative relationship between window size and game performance confirmed that superior players had a wider distribution of visual attention than inferior players. An additional analysis of eye movements showed that the mean length of saccadic eye movements (indicating an overt allocation of attention) of inferior players was comparable to that of superior players. These results suggest that the difference in game performance between inferior and superior players may be due to the qualitative difference in the efficiency of covert allocation of visual attention. The present study also indicates the applicability of the gazecontingent window method for the online evaluations of performance and learning during dynamic visual-motor tasks.

著者

Takashi Kawai Fumiya Matsumori Hidemi Akimoto Naoki Sakurai Ken Hirano Ryohei Nakano Fumio Fukuda

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-012, (Released:2018-07-14)

被引用文献数

15

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Split pit in peach (Prunus persica (L.) Batsch) fruit is an internal disorder that can have adverse effects on fruit quality and shelf stability. As it is difficult to distinguish split-pit fruit from normal fruit by appearance, a nondestructive detection method is desirable to determine accurately the timing of split-pit occurrence and remove unwanted fruit from trees. In our recent study, we used an acoustic vibration method for the nondestructive detection of split pit in harvested peach fruit. Here, we demonstrate that this method can be used to detect split pit in unpicked peach fruit. Time-course monitoring of growing fruit revealed that the ratio of the third (f3) to the second (f2) resonant frequency (f3/f2), which is an indicator of split pit in harvested fruit, abruptly increased in unpicked split-pit fruit from early June to early July. In contrast, the f3/f2 values of normal fruit remained low until harvest in late July. The increase in f3/f2 values of split-pit fruit was observed in early June (stage II of fruit growth) and/or from late June to early July (stage III of fruit growth), suggesting that, at least under the experimental conditions in the current study, pit splitting occurred at these two different timings. Split-pit fruit detection rate at harvest increased towards the end of the second split-pit occurrence and split pit could be predicted with high accuracy thereafter. These results collectively suggested that the timing of split-pit occurrence in unpicked peach fruit could be predicted accurately by measuring f3/f2 values and unwanted fruit with split pit could be distinguished from normal fruit on trees. We discuss the possible applications of the nondestructive acoustic vibration method in combination with fruit thinning and the future use of this method in research aiming to develop effective prevention methods or resistant cultivars with reduced split pit.

著者

Ryohei Nakano Hidemi Akimoto Fumio Fukuda Takashi Kawai Koichiro Ushijima Yosuke Fukamatsu Yasutaka Kubo Yuichiro Fujii Ken Hirano Kunihisa Morinaga Naoki Sakurai

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-094, (Released:2017-10-12)

被引用文献数

15

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Split-pit in peach fruit is a problematic disorder. Split-pit fruit cannot be detected based on external appearance, and contamination of fruit by split-pit reduces its reliability in the marketplace. Here, we demonstrate that split-pit fruit can be identified by a nondestructive acoustic vibration method and a unique approach based on the ratio of the third (f3) to the second (f2) resonant frequency. The response-resonant frequency spectra showed that the peaks of f2 frequencies in split-pit fruit were shifted to much lower values than those in normal fruit, whereas those of f3 frequencies showed only small shifts. The calculated f3/f2 ratios in most normal fruit were in the range of 1.35–1.4, whereas those in split-pit fruit were 1.45–2.0. Analysis of more than 300 fruit samples revealed that by setting the f3/f2 cut-off value at >1.45, 95% of split-pit fruit in the fruit samples were detected, whereas only 1.5% of normal fruit were missorted as split-pit fruit. A model for simulating the vibration properties of peach fruit was developed by using the finite element method. The simulated vibration patterns showed that f3/f2 values were increased by the insertion of split pit, indicating that, at least partially, the observed high f3/f2 values in split-pit fruit directly reflected split-pit occurrence. These results clearly demonstrate that the use of f3/f2 ratios obtained using an acoustic vibration method can effectively detect fruit with split-pit. The possibility of installing acoustic vibration devices in peach sorting lines and the application of portable devices to unpicked fruit on the tree are discussed.

著者

Tsuyoshi Habu Hisayo Yamane Ippei Naito Soichiro Nishiyama Ayumi Nonaka Takashi Kawai Hisashi Yamada Ryutaro Tao

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-119, (Released:2016-02-09)

被引用文献数

8

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Japanese persimmon ‘Totsutanenashi’ (TTN) is a spontaneous small fruit mutant derived from ‘Hiratanenashi’ (HTN). To characterize the small fruit phenotype of TTN, we carried out a histological analysis, plant growth regulator treatments, and a transcriptome analysis using Illumina sequencing. The parenchymal cell number in TTN fruit was significantly less than in HTN fruit, and the parenchymal cell size in TTN fruit was also significantly smaller than that in HTN fruit at the later growing stage. However, the fruit size of TTN recovered by cytokinin treatments [50 or 200 ppm N-(2-chloro-4-pyridyl)-N′-phenylurea]. Thus, diminished cytokinin activity in TTN fruits may lead to less cell division in the early growing stage and less cell enlargement in the later growing stage. A large-scale transcriptome analysis was conducted using Illumina sequencing to determine the differences in gene expressions between TTN and HTN fruits. Illumina sequences were processed, resulting in 21,662,190 read pairs from HTN and 23,195,203 read pairs from TTN. After assembly of all sequences from HTN and TTN, 118,985 contigs (referred to as unigenes hereafter) ranging from 201 to 11,954 bases, with an average length of 915 bases, were obtained. Digital expression analyses revealed that the expression levels of 164 unigenes were significantly higher in HTN than in TTN, while the expression levels of 265 unigenes were significantly higher in TTN. A parametric analysis of gene set enrichment using the expression levels of unigenes showed that the biological process Gene Ontology categories of “cell cycle” and “regulation of cell cycle” were significantly down-regulated in TTN. The cell cycle-related differentially expressed genes included D3-type cyclin and Mitogen-Activated Protein Kinase Kinase Kinase. Based on the obtained results, the possible involvement of cell cycle-related genes in regulating the small fruit phenotype in TTN is discussed.

著者

Sanghyun Kim Hiroyuki Morikawa Reiko Mitsuya Takashi Kawai Jukka Häkkinen

出版者

一般社団法人 日本人間工学会

雑誌

人間工学 (ISSN:05494974)

巻号頁・発行日

vol.49, no.Supplement, pp.S424-S427, 2013-06-01 (Released:2013-07-19)