• Korean Journal of Optics and Photonics
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• v.30 no.6
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• pp.237-242
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• 2019

A compact virtual-reality (VR) device with wider field of view provides users with a more realistic experience and comfortable fit, but VR lens distortion is inevitable, and the amount of distortion must be measured for correction. In this paper, we propose two different full-field distortion-measurement methods, considering the characteristics of the VR device. The first is the distortion-measurement method using multiple images based on camera calibration, which is a well-known technique for the correction of camera-lens distortion. The other is the distortion-measurement method by measuring lens distortion at multiple measurement points by rotating a camera. Our proposed methods are verified by measuring the lens distortion of Google Cardboard, as a representative sample of a commercial VR device, and comparing our measurement results to a simulation using the nominal values.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.212-215
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• 2017

In this paper, VR game was produced to inform the danger of using smartphone while walking and to raise awareness. In this VR games, you can experience Smombie (smart phone and zombie compound word) like a real situation by using Google card board and Bluetooth controller. Designed as a directions game of everyday material, the user indirectly experiences the dangerous situations that may actually occur in everyday life. In the virtual space, you can see the map on the smartphone, navigate the route, and send text messages using the controller during the game. We will explain how to implement smartphone map and send text message using controller which are the main functions of VR game.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.315-319
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• 2007

This paper presents a algorithm, what is able to recognize 4 different continuous human motion using a single stationary camera as input. For the first step, we acquire images from a camera. To enhance the image, we perform preprocessing which deals with removing noise using median filter, thresholding. And then morphological operations are performed to remove which small blobs and eliminates small holes. At the forth step, blobs are analysed to extracts for foreground region. Then, motions are predicted from these images by using optical flow technique, and the predicted motion data are refined by comparing our cardboard models so as to judge behavior pattern.

• Journal of applied mathematics & informatics
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• v.6 no.2
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• pp.417-432
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• 1999

This paper describes a fuzzy system designed to support production planning in an industrial unit producing cardboard boxes. In this industrial unit orders for n boxes of width w, length l, height h, made of q layers of type k paper for delivery in t units of time are produced. In the production of such orders apart from meeting the orders specifications it is usually tried to minimize the margin trim loss the number of machine setups and the holding cost of the finished orders. Considering the dynamism of production systems that are influenced by such factors as market demand fluctuations changes in commercial priorities raw material availability and pro-ducation capabilities we solve this multi-objective problem by fuzzy set theory.

• Korean Journal of Child Studies
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• v.25 no.1
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• pp.13-29
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• 2004

In this study of strategies used by young children in solving rectangular covering tasks before they have been taught area measurement, 75 5-, 6-, and 7-year-old children were asked to solve 3 rectangular covering tasks with a moveable unit. Three different sized units (4 cm., 2 cm., and 1 cm. cardboard squares) were provided and the children were asked to work out how many would be needed to cover a drawn rectangle. The resulting 5 developmental levels include incomplete covering, incomplete arrangement, complete covering, estimating, and measuring. Children using more advanced strategies were able to find correct number of units. While the tendency among older children was to use more advanced strategies, even 5-year-olds had an intuitive understanding of rectangular area measurement.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.537-641
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• 2007

In this paper, motion analysis algorithm is presented for home surveillance of the aged who lives alone. For the first step, we acquire images from a camera. To enhance the image, we use median filtering and binarize it to reduce processing time. And then morphological operations are performed to remove small blobs and small holes. At the forth step, blobs are analysed to extracts tor foreground region. Then, motions are predicted from these images by using optical tlow technique, and the predicted motion data are refined by comparing our cardboard models so as to judge behavior pattern.

• Journal of the Korea Furniture Society
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• v.17 no.1
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• pp.73-81
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• 2006

Since early times, paper has been the leading means of expression in human civilization. Along with the development of languages, people have used paper as their major intermediation measures to flourish the culture. At this point of time when studies in latest design are various and abundant, these fixed ideas on paper should be eliminated first for inventive thinking and freedom of expression. Because breaking the established notion helps to diversify the function of paper. We can see furniture made of paper come in useful to our ancestors in their daily life with the development of "Hanjiquot;. Each piece of paper furniture had its own function and beauty depending on processing method. Not only has been used for materials of basic modeling in the process of modern furniture designing, paper has also been used for the main material for the purpose of a new trial. If we try to find out the ways to take diverse characteristics of paper and develop them, while overcoming the defects of the material, paper has great potentiality for many kinds of use in furniture industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.759-762
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• 2005

A tray inserting machine is developed for automation of inserting plastic mold tray into a cardboard box. Plastic mold tray is used for protecting breakdown of glass bottles. In this paper, two types of processes to divide the plastic mold tray are proposed. As a result, adhesion method by vacuum pad is accepted. And also, static and modal analysis for the machine are carried out to check the machine design using the commercial software, CATIA V5.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1296-1302
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• 2013

The quality of fresh jujube (Zizyphus jujuba) fruit rapidly declines in the postharvest stage and thus the effective storage conditions for agricultural warehouses were investigated in this study. Fresh jujubes (~10 kg) were stored using five different storage methods: plastic box without further packaging as a control (C-PL), plastic box with hanji packaging (H-PL), plastic box with functional film packaging (F-PL), cardboard box with hanji packaging (H-CB), and cardboard box with functional film packaging (F-CB). The storage boxes were stored in a refrigerator ($0^{\circ}C$ and 80~90% RH), equipped with an ethylene gas scavenging device for 9 weeks and then the quality characteristics were analyzed. The control storage conditions of jujubes showed a substantial decline in quality with decreases in moisture content, hardness, and sugar content as well as increases in decay ratio and redness. Among the tested storage conditions, F-CB was most effective in terms of maintaining the quality of jujube fruit while maintaining firmness, weightlessness, ripening degree from redness and visible appearance. In conclusion, effective storage and packaging conditions during storage enabled maintenance of fruit quality of jujubes for 9 weeks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.249-258
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• 2006

In this letter, we propose a novel printed helix antenna for RFID reader in UHF band. The printed strip line of the antenna is first wound up outside a polygonal shaped layer and then the winding continues on an inner layer to control the overall gain and the radiation pattern. In addition, the winding pitch angles on each layer have either negative or positive values resulting in the broad CP bandwidth. The detail structure of the antenna was optimized using Pareto genetic algorithm(GA), so as to obtain excellent performances for RFID reader antennas. The optimized two-layered polygonal helix was fabricated on the cardboard of a flexible substrate and the performances were measured and compared with the simulations. The fabricated antenna was made up of copper tape which can adhere to a flexible cardboard and had 21.4 % matching bandwidth, 31.9 % CP bandwidth, readable range of $5.5m^2$ with kr=3.2. Also based on the current distribution of the strip line of the antenna and sensitivity of the antenna bents points, we confirmed that the antenna has the quarter-wave transformer near the feed for the broad matching bandwidth and radiates the traveling wave for the broad CP bandwidth using the bent strip line.