용접 불량 검사를 위한 음향공진 검사 장치 개발

염우정,강준희,홍연찬,Yeon Chan Hong 한국센서학회 2019 센서학회지 Vol.28 No.6

We have developed an acoustic resonance inspection system to inspect the welding defects in the mechanical parts fabricatedusing friction stir welding method. The inspection system was consisted of a DAQ board, a microphone sensor, an impact hammer, and controlled by a PC software. The system was developed to collect and analyze the sound signal generated by hitting the sample with an impact hammer to determine whether it is defective. In this study, 100% welded good samples were compared with 95%, 90%, and 85% welded samples, respectively. The variation of the completeness in welding did not affect the visual appearance in the samples. As a result of analyzing the natural frequencies of the good samples, the five natural frequency peaks were identified. In the case of the defective samples, the frequency change was observed. The welding failuredetection time was fast enough to be only 0.7 seconds. Employing our welding defect inspection system to the actual industrialfield will maximize the efficiency of quality inspection and thus improve the productivity.

전시참가업체 부스 운영요원의 고객 응대 특성이 라포, 장기거래지향성에 미치는 영향

염우정,김영선,김봉석 한국무역전시학회 2022 무역전시연구 Vol.17 No.2

Despite the recent change to customer-oriented sales that match the important values ​​of individual customers, a response at customer contact points is becoming more important. Still, studies on the relationship and influence between visitors and booth staffs at exhibitions are used as an essential marketing tool for companies are lacking. In this study, we tried to examine the relationship between customer orientation and sales orientation, which are the response characteristics of booth staffs of exhibitors, on the formation of rapport of visitors, and how they affect trust in exhibitors and long-term transaction orientation. For this study, a questionnaire was conducted on visitors who participated in the exhibition and had experience interacting with booth staffs of exhibiting companies, and 306 valid samples among the collected data were used as final analysis data. As a result of the final analysis, it was found that the customer orientation of the booth operator had a positive effect on the formation of rapport and the sales orientation had a negative impact on the building of rapport was found to have a positive effect on trust. In addition, it was found that the visitors' trust in the exhibitors had a positive impact on the long-term transaction orientation toward the exhibitors. Through this study, booth staffs of exhibitors respond so that they can feel that they are receiving customer-oriented services, and accordingly when visitors feel a rapport with booth staffs, trust in exhibitors, and long-term transaction orientation, it was confirmed that it had a positive effect. For exhibitors to achieve the purpose of participation, it is necessary to build trust for long-term transactions rather than focusing only on short-term sales performance.

실시간 기름유출 모니터링 기술에 관한 연구

염우정(Woo-jung Yeom),홍연찬(Yeon-Chan Hong) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.2

기름 유출로 인한 피해는 수질환경 및 생태계를 단시간에 파괴할 뿐만 아니라 한번 오염이 되면 회복하는데 상당한 시간이 걸리고 회복이 어려우며, 지속적으로 나타난다. 때문에 해양이나 하천, 담수 등의 기름유출을 모니터링할 수 있는 오일 검출기의 필요성이 매우 높다. 오일을 검출할 수 있는 기술로는 크게 접촉식과 비접촉식으로 구분할 수 있으며, 접촉식으로는 Conductivity, Capacitance, Microwave 등이 있고 비접촉식으로는 Infrared, UV, Laser, Optic, Radar 등으로 구분할 수 있다. 수면 위에 있는 오일을 측정하기 위해서는 파고 및 너울, 빛의 산란, 온도, 염도 등 여러 가지 관측의 장애가 존재하기에 측정하고자 하는 환경에 맞는 오일 검출기를 선택하여 사용해야 한다. 본 논문에서는 접촉식 방식으로 정유회사 및 유화회사, 발전소 등의 오일 관련 업종에서 사용할 수 있는 오일 검출기를 구현하였다. 장비의 구성은 수면 위에 띄워 놓는 센서 모듈과 센서 모듈에서 들어오는 신호를 가공하여 표시하는 제어기로 구분하며, 센서를 통하여 오일의 유무를 판별하고 더 나아가 오일의 양과 오일의 종류에 따른 유전율의 변화를 관측하였다. Oil spills cause a lot of damage to the environment. Oil destroys the water environment and ecosystem in a very short period of time once they are contaminated by it, it takes a lot of time to recover from the contamination and the cleaning process is very difficult. Therefore, oil detectors are greatly needed as they can monitor any oil spills over the sea, rivers, and lakes. There are two kinds of technology available for detecting oil, viz. the contact and non-contact types. The former is based on the use of the conductivity, capacitance and microwaves, while the latter employs infrared, UV, laser, optic and radar technologies. As there are also various hurdles in the measuring of oil on water, such as the presence of waves, refraction of light, temperature and saltiness, it is imperative to select the right oil detector which is appropriate for the specific environment. In this study, a contact type oil detector is developed, which can be used in oil related industries, such as refineries, petrochemical companies, and power generation stations. The detector is made up of the sensor module, which floats on the water, and the controller which processes the signal coming from the sensor module and displays it. It is designed in such a way that the existence of oil is detected through the sensor and the change in the permittivity is observed to determine the volume and type of spilled oil.

음향 공진 스펙트럼 분석을 통한 요크 튜브 크랙 검사

염우정(Woo-Jung Yeom),홍연찬(Yeon-Chan Hong),김진영(Jin-Young Kim),강준희(Joonhee Kang) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.10

비파괴 검사 기술의 발달로 인해 기계부품의 크랙을 검사하는 방법들이 주목을 받기 시작하였다. 다양한 비파괴 검사 방법 중에서도 고유 주파수를 분석하는 음향 공진 방법은 빠른 시간 안에 제품의 불량 여부를 판정하는데 적합한 기술로 발전했다. 본 연구에서는 기계부품 중 요크 튜브의 크랙을 검사하기 위한 크랙 검사기술에 대해 연구를 진행하였으며, 음향 공진 방법으로 빠르게 검출이 가능한 시스템을 구현하였다. 24bit ADC 회로를 탑재하였으며, 원활한 데이터 수집을 위해 MCU를 탑재하였으며, PC와 데이터 통신을 위해 TCP/IP 통신 인터페이스를 구성하였다. 데이터 측정을 위한 센서는 마이크로폰을 사용하였으며, 크랙 정보를 판정하고 사용자에게 피드백하기 위한 분석 소프트웨어를 구현하였다. 실제 산업현장에서 제작한 요크 튜브를 사용하여 테스트를 진행하였다. 양품과 크랙이 있는 불량제품을 구별하는 테스트를 성공적으로 실시하여 실제 산업현장에 적용할 수 있음을 확인하였다. Due to the development of nondestructive testing techniques, methods of inspecting cracks in mechanical parts have drawn attentions. Among various non-destructive testing methods the acoustic resonance method which analyzes the natural frequencies has been developed into a technique suitable for the prompt judgements of the existence of the defects in the mechanical parts. In this study, we investigated the crack inspection technique to examine the cracks in the yoke tubes by using the acoustic resonance method and realized the system to quickly detect the cracks. A 24bit ADC circuit and an MCU were installed for the smooth data collection, and a TCP / IP communication interface was configured for the data communication with PC. We used a microphone as a sensor measuring the vibrations. We constructed an analysis software to obtain the frequency spectra of the vibrations, to find the existence of the cracks, and to feedback to the user. Tests were conducted using the yoke tubes manufactured in the real industrial field. The tests were successfully conducted to distinguish the good products from the defective (cracked) products and confirmed that they can be employed in the actual industrial field.

Primary Melanoma of the Breast: A Case Report with Imaging Findings

염유경,차주희,김학희,신희정,채은영,최우정,송인혜 대한영상의학회 2015 대한영상의학회지 Vol.73 No.5

Primary breast melanoma is extremely rare, and as such, there are no established radiologic findings in the literature. This report describes a case of primary malignant melanoma with mammography, ultrasonography, and magnetic resonance imaging findings. Our case study demonstrates a well-circumscribed heterogeneous rim-enhancing mass, with an internal cystic or necrotic portion seen using three modalities. Thus, although rare, this condition should be included in the differential diagnosis of a well-demarcated heterogeneous breast mass, and further pathological confirmation is needed.