• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.799-800
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• 2012

• 한국환경과학회지
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• 제19권12호
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• pp.1447-1454
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• 2010

In this study, the detection limits of lower fatty acids in air were investigated by using Dynamic SPME(Solid Phase Micro-Extraction), i.e. improved Head Space - SPME method(HS-SPME). This Dynamic SPME, called SPDE(Solid Phase Dynamic Extraction), is the analytical method for volatile compounds in air with the extraction by using a stainless steel needle of which inner surface is coated with adsorption material and following the gas chromatographic analysis by inserting the needle into a injection port of GC and subsequently, desorption of the volatile compounds into a gas-chromatographic column. Extraction was carried out by passing the sample air through the needle with a suction pump which has been used for a detection tube. The result of measurement for the 6 lower fatty acids showed that the detection limits ranged from 0.10 ppm to 0.44 ppm and the linear correlation coefficients were over 0.99. Relative standard deviations obtained from 5 analytical repetition of a ca. 1.6 ppm standard mixture were in the range of 1.87%~2.47%. This method has been shown to be a adequate for the measuring C2~C5 fatty acids in air in the concentrations of over several hundreds ppb.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1539-1543
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• 2004

This paper describes platform overview, system integration and dynamic walking control of the humanoid robot, KHR-2 (KAIST Humanoid Robot - 2). We have developed KHR-2 since 2003. KHR-2 has totally 41 DOF (Degree Of Freedom). Each arm including a hand has 11 DOF and each leg has 6 DOF. Head and trunk also has 6 DOF and 1 DOF respectively. In head, two CCD cameras are used for eye. In order to control all joints, distributed control architecture is adopted to reduce the computation burden of the main controller and to expand the devices easily. The main controller attached its back communicates with sub-controllers in real-time by using CAN (Controller Area Network) protocol. We used Windows XP as its OS (Operating System) for fast development of main control program and easy extension of peripheral devices. And RTX, HAL(Hardware Abstraction Layer) extension program, is used to realize the real-time control in Windows XP environment. We present about real-time control of KHR-2 in Windows XP with RTX and basic walking control algorithm. Details of the KHR-2 are described in this paper.

• 정보처리학회논문지C
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• 제12C권6호
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• pp.875-880
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• 2005

제한된 자원을 가진 센서 노드들로 구성된 센서 네트워크에서 가장 중요한 이슈 중 하나는 쑤어진 에너지를 최대한 활용하여 네트워크 수명을 연장하는 것이다. 네트워크 수명을 연장하는 가장 대표적인 방법은 클러스터링 방법이다. 본 논문에서는 CH(Cluster Head) 및 후보 CH 노드들로부터 주어지는 통신 부하(load)와 잔여 에너지 양에 대한 정보를 기반으로 클러스터 크기를 동적으로 변화시켜 클러스터 내의 노드 밀도에 상관없이 각 CH에게 주어지는 부담을 일정하게 유지시키는 새로운 동적 크기 다중홉 클러스터링 방법을 제안한다. 시뮬레이션을 통해 제안된 방법이 기존의 단일홉 모드나 고정 크기 다중홉 모드 클러스터링 방법보다 우수함을 보였다.

• 한국소음진동공학회논문집
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• 제16권1호
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• pp.75-80
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• 2006

This paper introduces the mechanism of the ESD(electrostatic discharge) in the HDD spindle system using FDBs(fluid dynamic bearings). When a HDD(hard disk drive) spindle system is rotating, triboelectric charging occurs in the FDBs through the friction between the lubricant and the rotating shaft or between the lubricant and stationary sleeve. And this electrostatic charge is accumulated in the rotating parts of the HDD spindle system because they are insulated from the ground by the lubricant. This research shows experimentally that the behavior of electric charge and discharge in the FDB spindle system is the same as that of a capacitor. It also measures the electrostatic voltage difference between the rotating and stationary parts in the FDB spindle system due to the change of humidity, supporting load and motor speed. This research shows that the control of ESD is required in the HDD spindle system using FDBs, because the electrostatic charge accumulated in the FDB spindle system may cause the breakdown damage of the GMR head and data loss consequently.

• 한국항해항만학회지
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• 제30권5호
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• pp.369-374
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• 2006

복잡한 연료실 내의 유동현상을 난류모형을 적용하여 해석하였다. 적용한 모형은 $k-\varepsilon,\;k-\omega$, spalart-allmaras, reynolds stress이고, 연로실내의 격자는 혼합격자(hybrid grid) 이다. 속도벡터, 압력분포, 반복계산(iteration)에 의한 잔류치(residual), 동력학적 양정(dynamic head) 등을 모사하였다. 4개의 난류모형을 연료실 유동에 적용하였다. 3차원 수치실험에 앞서, 수치검증을 위하여 2차원 물체 주위의 점성유동을 $k-\varepsilon$ 난류모형을 적용하여 모사하였고 항력계수를 비교하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.318-323
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• 2005

This paper introduces the mechanism of the ESD (Electrostatic discharge) in the HDD spindle system using FDBs (Fluid Dynamic Bearings). When a HDD (Hard Disk Drive) spindle system is rotating, triboelectric charging occurs in the FDBs through the friction of the lubricant between the rotating shaft and stationary sleeve. And this electrostatic charge is accumulated in the rotating part of the HDD spindle system because it is insulated from the ground by the lubricant. This research shows experimentally that the behavior of electric charge and discharge in the FDB spindle system is the same as that of a capacitor. It also measures the electrostatic charge and discharge of the FDB spindle system due to the chanse of humidity, supporting load and motor speed. This research shows that the control of ESD is required in the HDD spindle system using FDBs, because the electrostatic charge accumulated in the FDB spindle system may cause the breakdown damage of the GMR head and data loss consequently.

• 한국기계가공학회지
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• 제18권6호
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• pp.98-105
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• 2019

In order to improve the fuel economy and dynamic behavior of automobiles, the weight reduction tendency of automobile parts is obvious. Also, in order to maximize assembly and maintenance convenience, various parts are integrated and modularized. Multi-piece methods require many manufacturing processes and become a factor of lowering the strength of parts. It is advantageous to overcome the disadvantages by integrally manufacturing to reduce the processing steps and ensure the strength of the parts. However, when it is necessary to process in a narrow space inside the part, it is impossible to process with the existing spindle. The angle head spindle is only a component of a machine tool, but it is a core part that requires high technology and is highly utilizable in products requiring high precision machining. Therefore, various and continuous studies needs for angle head spindles in areas such as vibration absorption, operational safety, excellent dimensional stability, and strength. In this paper, we propose an optimal design for angle head spindle by performing structural analysis and shape optimization for angle head spindle gear and case.

• The Journal of Korean Physical Therapy
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• 제27권6호
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• pp.407-412
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• 2015

Purpose: This study aimed to evaluate changes in the balance ability of patients whose head positions were altered due to stroke. Subjects were divided into three groups to determine the effects of the training on dynamic balance and gait. Methods: Forty-two stroke patients were enrolled. The Visual Feedback Training (VFT) group performed four sets of exercises per training session using a Sensoneck device, while the Active Range of Motion (ART) group performed eight sets per training session after receiving education from an experienced therapist. The Visual Feedback with Active Range of Motion (VAT) group performed four sets of active range of motion and two sets of visual-feedback training per session using a Sensoneck device. The training sessions were conducted three days a week for eight weeks. Results: The comparison of changes in dynamic balance ability showed that a significant difference in the total distance of the body center was found in the VFT group (p<0.05) and Significant differences were found according to the training period (p<0.05). The comparison of the 10 m walk test showed that the main effect test, treatment period and interactions between group had statistically significant differences between the three groups (p<0.05). Conclusion: Head-adjustment training using visual feedback can improve the balance ability and gait of stroke patients. These results show that coordination training between the eyes and head with visual feedback exercises can be used as a treatment approach to affect postural control through various activities involving the central nervous system.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.38-43
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• 2011

센서 네트워크에서 사용되는 동적 클러스터링 방식은 주기적으로 클러스터 구조가 바뀌는 셋업과정으로 인한 에너지 소모가 크다. 셋업과정은 보안적용을 해야 할 경우 보안 키가 주기적으로 재 생성되는 등 클러스터 구성 이외에 추가적인 에너지 낭비가 발생한다. 본 논문은 최초에 구성된 클러스터 알고리즘과 이후 반복적으로 발생되는 클러스터 재셋업 알고리즘을 달리하는 하이브리드 방식을 제안한다. 재 셋업에서는 고정된 클러스터 내에서 순환적으로 클러스터 헤드노드를 선출하는 순환적 클러스터 헤드선정(RRCH: Round-Robin Cluster Header)방식을 이용하여 에너지 소모를 줄인다. 보안키 생성 및 적용으로 추가되는 에너지 소모는 클러스터가 지속적으로 고정되기 때문에 최초 클러스터 형성 때 사전 배포하는 방식으로 해결된다. 본 논문에서 제안한 방식의 타당성을 확인하기 위해 모의실험을 실시하였다. 라운드 구간을 100번 반복하여 클러스터 구성과 데이터 전송을 포함한 전체 에너지 소모량을 측정하였다. 결과는 제안한 방식이 LEACH방식보다 평균 26.5%, HEED방식보다 평균 20% 적게 소모되는 것을 확인하였다.