• 한국기계가공학회지
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• 제13권5호
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• pp.28-34
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• 2014

A planetary gear train is more compact and endures greater amounts of transmission power compared to other gear systems. Although planetary gear systems operate in small volumes, they are capable of very high efficiency due to the compact combination of their gears in the planetary gear system. They also have outstanding efficiency of only 3% for power transmission, tantamount to the power loss that occurs in each of the shift stages. Given these advantages, planetary gear systems are used in the driving systems of, which are widely used in automobile transmissions, machine tools, semiconductor equipment, and in other areas in industrial fields. Current structural equipment requires higher efficiency and greater torque levels. According to these needs, we have designed a complex planetary gear system which creates higher levels of torque. In this paper, an evaluation of strength designs for the proposed planetary gear system was conducted to ensure the stability of the gear. In addition, a durability analysis based on Miner's rule was performed using RS B 0095 device.

• 한국CDE학회논문집
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• 제12권1호
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• pp.39-49
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• 2007

Recently three-dimensional (3-D) die design and production process has been widely introduced into the tooling shops of automotive manufacturers to reduce time-to-production of brand-new automobiles. 3-D solid models created in CAD systems are used not only for various simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns. However, a lot of time and cost will be required to build solid models for dies if designers use only the generalized modeling capabilities of commercial 3-D CAD systems. To solve this problem, it is necessary to customize 3-D CAD system for the specific die design and manufacturing process. This paper describes a dedicated 3-D CAD system based on Unigraphics for die design for automotive body panels. The system provides not only 3-D design capabilities, but also standard part libraries, to enhance design productivity. The design process modeling technology has been introduced to facilitate redesign of the die for the modified panel. By introducing this system, dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing.

• 한국지능시스템학회논문지
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• 제5권2호
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• pp.3-12
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• 1995

A controller utilizing fuzzy logic is developed to control the speed of a motor in a washing machine by choosing an appropriate phase. Due to the hardship imposed on obtaining a result from a relation established for inputs, present speed and present rate of speed, and ouput, a phase, of the system that can be tested against an experimental result, it is impossible to apply a genetic algorithm to fine-tune the fuzzy logic controller. To avoid this difficulty, a proper assumption that the parameters of an if-part of a primary fuzzy logic controller have a functional relationship with an error between computed values and experimental ones in made. Setting up of a fuzzy relationship between the parameters and the errors is then achieved through experimentally obtained data. Genetic Algorithm is then applied to this secondary fuzzy logic controller to verify the fuzzy logic. In the verification process, the primary fuzzy logic controller is used in obtaining experimental results. In this way the kind of difficulty in obtaining enough experimental values used to verify the fuzzy logic with genetic algorithm is gotten around. Selection of the parameters that would produce the least error when using the secondary fuzzy logic controller is done with applying genetic algorithm to the then-part of the controller. In doing so the optimal values for the parameters of the if-part of the primary fuzzy logic controller are assumed to be contained. The experimental result presented in the paper validates the assumption.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.521-524
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• 2000

Nearinfra-red(NIR) reflectance NIR a spectra (400 to 2,100 nm) were collected on 32 beef samples to find feasibility of predicting beef tenderness. The study to predict beef tenderness was accomplished with the stepwise second differential data of the collected NIR spectra. Beef tenderness was measured by Warner-Bratzler(WB) shear force using a Universal Testing Machine(UTM). After modeling the relation between Warner-Bratzler shear force and NIR spectrum of 19 samples among the 32 beef samples, the verification was carried out through predicting the other 13 samples. The SEC and R$^2$ values in the prediction equation were 9.07(N) and 0.6463, respectively. The SEP and R$^2$ were 14.8(N) and 0.7082 (wave length 552 nm, 1988 nm) respectively. The result implied that it was possible to predict the beef tenderness using NIR spectrum and that the tenderness could be predicted non-destructively in real time.

• 한국정밀공학회지
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• 제32권12호
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• pp.1049-1054
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• 2015

Nowadays, there are many researches involving structural actuators, which have adjustable stiffness; they are also called variable stiffness actuators (VSA). The VSAs can adjust the characteristics of actuators for various functions and human-machine safety. This paper describes the design and analysis of two types of VSAs. To adjust stiffness, the actuators are controlled by a principle of lever ratio mechanism, by changing a pivot position or a spring position in the structure with springs. To make the principle workable, the designs are simplified by using a ball screw system with a motor. Each structure shows different static properties with variable rates of stiffness. We have also shown the experimental verification of the dynamic performance of the two types of VSAs. This research can be applied to various industrial fields, where humans work in conjunction with robots.

• 전력전자학회논문지
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• 제7권4호
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• pp.377-383
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• 2002

유도전동기의 고성능 벡터제어를 수행하기 위해서는 회전자 자속의 정확한 추정이 필요하다. 유도전동기의 회전자 자속관측기들에서는 자속추정시에 전동기 상수들이 사용되므로 이들의 변동에 따라 자속추정에 영향을 받는다. 본 논문에서는 파라미터 민감도를 이용하여 파라미터 변동에 의한 자속관측기들의 추정자속 오차를 해석하였다. 파라미터 민감도는 시스템 파라미터의 변동분에 대한 시스템 전달함수의 변동분의 비로 정의되므로 실제 자속과 추정 자속의 비를 전달함수로 정의하고 해석을 수행하였다. 제안된 해석방법의 타당성을 확인하기 위해 시뮬레이션과 실험을 행하였다.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1117-1126
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• 2013

The standard impact sources, standardized to rate the sound insulation performance of floor structure, should simulate well the real floor impact sources, which is very important to grade the floor structure then to establish counter plan to improve the performance of floor. Recently the tire, the standard heavyweight impact source, has been discussed that the impact force is too big to represent the real impact force. And researches have been carried on the applicability as a substitute or a supplementary. In addition, tapping machine, the standard lightweight impact source, is also questionable if it is representative of real lightweight impact source. This study aims to examine the similarity of standard impact sources with living impact sources, comparing the physical characteristics such as impact force, frequency contents and sound level. The result showed that the physical characteristics of standard impact sounds were somewhat different with that of living impact sounds, and the standard sources couldn't be verified from this result. Later subjective evaluation should be followed to compare how the physical differences make relationship with the subjective differences.

• 전기전자학회논문지
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• 제24권2호
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• pp.486-491
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• 2020

본 논문은 ARM Cortex-M0 DesignStart를 기반으로 한 커스텀 시스템을 설계하는 방식을 정리하였다. ARM사에서 무료로 공개 배포하고 있는 ARM Cortex-M0 DesignStart를 활용하여 사용자가 원하는 ARM Cortex-M0 기반의 커스텀 시스템을 구현할 수 있다. 구현에 앞서 ARM Cortex-M0 기반의 하드웨어 구조와 특징을 살펴보고, 제공된 소프트웨어에 대하여 기술한다. 그리고 ARM Cortex-M0 DesignStart의 CMSDK(Cortex-M System Design Kit)을 활용하여 ARM Cortex-M0 기반의 UART 시스템 구현 및 테스트코드를 사용한 검증을 통해 ARM Cortex-M0의 커스텀 시스템 설계할 수 있음을 보인다.

• 디지털산업정보학회논문지
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• 제9권2호
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• pp.111-119
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• 2013

Face recognition has recently become one of the most popular research areas in the fields of computer vision, machine learning, and pattern recognition because it spans numerous applications, such as access control, surveillance, security, credit-card verification, and criminal identification. In this paper, we propose a simple descriptor called an ECSP(Extended Center-Symmetric Pattern) for illumination-robust face recognition. The ECSP operator encodes the texture information of a local face region by emphasizing diagonal components of a previous CS-LBP(Center-Symmetric Local Binary Pattern). Here, the diagonal components are emphasized because facial textures along the diagonal direction contain much more information than those of other directions. The facial texture information of the ECSP operator is then used as the input image of an image covariance-based feature extraction algorithm such as 2D-PCA(Two-Dimensional Principal Component Analysis). Performance evaluation of the proposed approach was carried out using various binary pattern operators and recognition algorithms on the Yale B database. The experimental results demonstrated that the proposed approach achieved better recognition accuracy than other approaches, and we confirmed that the proposed approach is effective against illumination variation.

• 융합보안논문지
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• 제13권2호
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• pp.95-100
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• 2013

근거리 무선통신 기술은 다양한 분야에서 그 응용범위가 점차 확대되고 있는 추세로, 다양한 종류의 기술 중에서 Mobile기반의 NFC(Near Field Communication)의 적용이 늘어나고 있다. URL 주소가 저장되어 있는 태그(RFID)에서 NFC 디바이스를 터치하면, URL 주소를 읽고 그 주소의 웹사이트에 접근을 지원하는 방식을 무인경비시스템에 적용하였다. 기존의 무인경비시스템과의 비교검증을 통하여 Integrity, Damage, Real-Time, Speed 측면에서 효율적인 출동경비업무 관리방안을 제시하였다.