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Evaluation on Applicability of New Milling Machine Assisted Plasma Torch
Mingyu Choi,Seoyong Choi,Sunghoon Hong,Jeongsu Jeong 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1
Various cutting technologies are being developed for dismantling nuclear power plants. these technologies are including mechanical and thermal methods. For example, mechanical cutting methods include sawing, drilling and milling. But, due to the strength of material, mechanical cutting methods have limits of cutting depth and tool life. Therefore, this milling machine assisted plasma torch was developed to improve the limits. And this machine has the principle of softening effect caused by the high temperature. In this work, this developed device was evaluated in view of the cutting depth and tool life in cutting process. For this process, a plasma torch was attached to the front of the endmill processing path to heat the Inconel 600. As results, compare to conventional milling, when the plasma torch power is 6.4 kW, the cutting depth was increased by 4 mm at condition (feed rate is 100 mm·min?1, tool diameter is 10 mm, rotating speed is 1,000 rpm). And cutting length increase 2 times from 300 mm to 600 mm at 16 mm of tool diameter.
Study on Applicability of Plasma Assisted Machining for Hard-Machining Materials
Mingyu Choi,Seoyong Choi,Sunghoon Hong,Jeongsu Jeong 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1
Many countries are developing various mechanical cutting technologies to dismantle nuclear facility. However, most of mechanical cutting technologies have a problem like the degradation of tool life due to the Hard-Machining materials. To solve this problem, lab-scale test was performed with a Plasma Assisted Machining (PAM) technology and 25 mm of thickness Inconel 600 plate. Commonly, the strength of metals decreases by exposure at high temperature. And, previous study reported that strength of Inconel 600 is degraded above 500°C. This softening effect was applied to Inconel 600 cutting test. The optimal conditions such as the plasma torch power and the feed rate were determined by this study. As a result, the surface temperature of Inconel 600 was reached up to 500°C under the conditions which is 8.4 kW of plasma torch power and 150–250 mm·min?1 of feed rate. And it was confirmed that the tool life was improved under the conditions. In order to apply PAM for various Hard- Machining materials, it is necessary to investigate the softening temperature of Hard-Machining materials, the plasma torch power and feed rate.
Relative Pointing : a New 3D Pointing Gesture Interface
Mingyu Lee,Hojin Lee,Eunjung Choi,Min K. Chung,Sung H. Han 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5
Studies on gesture interfaces have been conducted on natural and intuitive user manipulation of home appliances. The studies for the gesture interface can be divided into two categories: studies for deriving intuitive gesture vocabularies and studies for the technical implementation of gesture interfaces. The gesture vocabularies coming from both parts have limitations. In the former case, the gesture vocabularies lack usefulness because most studies rarely consider gesture recognition. In addition, in both cases, the studies suggest many gesture vocabularies for various appliances or functions, potentially making a user difficult to memorize gestures. To resolve the limitations, we suggested a new type of 3D gesture interface called Relative Pointing. Through Relative Pointing, users can exercise a function by pointing to a relative position in a virtual 3D menu, considering the distance and the angle from the reference point (starting point). Users can set the reference point freely and operate all the functions on the menu with only one gesture. In this study, we implemented a Relative Pointing system using Microsoft Kinect. To determine the total number of functions in the system, we conducted an experiment that divided the space into a virtual pie menu. A total of 20 participants divided a space into 4 to 8 equal parts, and errors and users’ subjective easiness for each division were analyzed. Relative Pointing can enable users to manipulate functions without memorizing a number of gesture vocabularies, so it can be useful in applying 3D gesture interfaces to various home appliances.
Performance Analysis and Optimization of Best-M Feedback for OFDMA Systems
Mingyu Kang,Kwang Soon Kim IEEE 2012 IEEE COMMUNICATIONS LETTERS Vol.16 No.10
<P>In this paper, the best-M feedback, where each user reports the channel quality indicators (CQIs) on its M best resource blocks (RBs), for orthogonal frequency division multiple access (OFDMA) systems is analyzed and optimized. First, the closed-form expression of the average sum-rate is derived as a function of M and the number of bits for a signal to noise ratio (SNR) quantization B. Then, M and B are jointly optimized to minimize the feedback overhead such that the desired system performance can be achieved. Numerical results confirm that the proposed analysis is quite well matched to the exact result so that our work is useful to optimize M and B instead of time-consuming computer simulations, and that the required feedback overhead to achieve a given performance decreases as the number of users and the average SNR increase.</P>
Observation of the Cosmic Near-Infrared Background with the CIBER rocket
MinGyu Kim,T. Matsumoto,Hyung Mok Lee,T. Arai,J. Battle,J. Bock,S. Brown,A. Cooray,V. Hristov,B. Keating,P. Korngut,Dae-Hee Lee,L. R. Levenson,K. Lykke,P. Mason,S. Matsuura,U. W. Nam,T. Renbarger,A. S 한국천문학회 2012 天文學會報 Vol.37 No.1
Investigating User Needs for Intelligence Services in IoT Environments
Mingyu Lee,Jiyoung Kwahk,Sung H. Han,Minseok Song,Dawoon Jeong,Minsu Cho,Dohyeon Kim,Deoksang Lee,Seokmin Oh,Hwanchul Kim,Gunho Chae 대한인간공학회 2018 대한인간공학회 학술대회논문집 Vol.2018 No.5
This study aims to identify users" needs for intelligence services in internet of things (IoT) environments. In the IoT environments, it is possible to recognize users’ behaviors and contexts through the data from the devices, and to provide services appropriate for the behaviors and contexts. IoT intelligence services are still in its infancy. It is necessary to understand the users’ needs on the IoT intelligence services, and to reflect them in product and service development. To identify the needs, this study conducted face-to-face interviews with potential users. Fifteen interviewees using various home appliances participated voluntarily. They answered what inconveniences they had in their daily lives and what services they would like to have to improve their inconveniences. The user needs on the IoT Intelligence have been classified based on the interview data. As a result, they hoped to be able to efficiently carry out the tasks of washing, cleaning, setting indoor temperature, cooking, and consuming groceries with the help of the IoT intelligence services. In addition, most user needs were related to the desire to simplify complex and cumbersome tasks. The results of this study can be applied to developing intelligence products and services using the IoT.