http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
End Effectors and Flexible Fixtures for Rapidly Holding Freeform-Surface CFRP Workpieces
손영훈(Younghoon Son),도민득(Minh Duc Do),최해진(Hae-Jin Choi) Korean Society for Precision Engineering 2017 한국정밀공학회지 Vol.34 No.4
In this study, flexible fixtures and end effectors are conceptually designed for the holding of thin-walled carbon-fiber reinforced-plastic (CFRP) workpieces in machining processes. Firstly, the fixture scenarios and system requirements for the conceptual designs of flexible-fixture and core units are proposed, including the propounding of the workpiece-holding mechanism and the core-unit requirements. A ball-joint pneumatic system is determined as a locking mechanism of the flexible-fixture system for the machining of thin-walled components. Secondly, conceptual designs of the core units are suggested with the driven requirements from the fixture scenarios. A self-tilting mechanism and an end-effector return mechanism are also proposed. Finally, the prototypes of the core units are manufactured, and the workpiece-holding capacity of each prototype is measured.
Son, Myeongsu,Lee, Taeyeong,Kwon, Soyeon,Cho, Younghoon The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4
This paper shows the relationship between the circuit parameters and the voltage sharing performance in series-connected insulated gated bipolar transistors (IGBTs). A simple analytic model is proposed to examine voltage balancing in series-connected IGBTs. By the proposed model, the reason for voltage imbalance is easily analyzed. In addition, the impact of the time constant of the snubber, which is affected by the snubber components, is detailed. From this analysis, it has been demonstrated that the snubber capacitance should be at least double the output capacitance of the switching device to stabilize voltage sharing. To verify the usefulness of the proposed technique, a multiple pulse tester has been implemented and tested. Experimental results reveal that the error between the proposed model and the practical system is only 1.7%. In addition, the accuracy of the proposed model is high enough to be utilized for the analysis of the series-connected IGBTs.
Development of MF R-Mode Transmitting System for Maritime Resilient PNT in the Republic of Korea
Younghoon Han,Pyo-Woong Son,Kiyeol Seo,Tae Hyun Fang 사단법인 항법시스템학회 2022 Journal of Positioning, Navigation, and Timing Vol.11 No.4
R-Mode is terrestrial based Global Navigation Satellite System (GNSS) backup radio navigation technology which used existing maritime information service infrastructure. It has advantages on reduce the cost and reutilize the frequency resource. In this paper, we propose a method to develop a medium-frequency (MF) band R-Mode transmitting station by utilizing the currently operating Differential GNSS (DGNSS) reference station infrastructure. To this end, the considerations for co-operating the DGNSS reference station and the MF R-Mode transmitting station are analyzed. In this process, we also analyze what is necessary to configure the communication system as a navigation system for range measurement. Based on the analysis result, MF R-Mode transmitting station system is designed and architecture is proposed. The developed system is installed in the field, and the performance evaluation results is presented.
Han YoungHoon,Song YoungMin,Kim Geun Woo,Ha ChangSu,Lee JiSun,Kim MinHee,Son HyeYoung,Lee GiYong,Gautam Ravi,Heo Yong 한국독성학회 2021 Toxicological Research Vol.37 No.4
Microplastics (MPs) have been recently recognized as a global environmental threat and its exposure as a risk factor to human health. Health effects through MPs exposure have been recently reported, especially through oral route of exposure. Since MPs could be exposed to humans through routes other than oral, this study was designed to evaluate whether MPs exposed through the inhalation route could be delivered to fetal mice and exhibit systemic toxicity. Polyethylene (PE) with 10–45 μm diameter were administered at 0 (distilled water, vehicle control), 6 (low administration), and 60 (high administration) μg/ mouse/day to 3 pregnant dams per group from gestational day 9 to postnatal day (PND) 7 through intratracheal instillation. Dams and neonates were sacrificed at PND 7 and blood was collected. Various neonatal organs including brain, lung, heart, stomach, intestine, kidneys, and ovaries were collected for histopathological observation and weight measurement. No influence of PE-MPs administration was observed on the number of offsprings born, but the body and organs’ weight were heavier overall in the high administration group of dams and neonates than the other groups with statistical significance achieved in the heart and spleen weight. Level of serum acetylcholinesterase and glutathione peroxidase activity was decreased in the high administration group of dams and neonates compared with the other groups. Lung was the organ with highest number of PE-MPs present in the both administration groups of dams, and PE-MPs were also detected in liver and intestine of the high administration dams. Whereas, PND7 neonates showed accountable numbers of PE-MPs only in kidneys of the high administration group. Overall, the present study indicates that PE-MPs instilled intratracheally could be delivered to neonates from dams. Even though adverse effects from PE-MPs exposure during pregnant and lactational period are less prominent on both dam and neonate, potential of second-generation toxicity could be considered for further investigation.
Risk Factors of Failure to Rescue in Unplanned ICU Admitted Patients after Elective Pancreatectomy
Jimin Son,Ki Byung Song,Ye Won Jeon,Janghun Han,Min Kyu Sung,Yuna Lee,Younghoon Roh,Sarang Hong,Yejong Park,Bong Jun Kwak,Woohyung Lee,Jae Hoon Lee,Dae Wook Hwang,Song Cheol Kim,Suk-kyung Hong 대한외과학회 2022 대한외과학회 학술대회 초록집 Vol.2022 No.11
손정민(Jeongmin Son),이정훈(Jeonghun Lee),김영훈(Younghoon Kim),심규석(Kyuseok Shim) 한국정보과학회 2014 정보과학회 컴퓨팅의 실제 논문지 Vol.20 No.5
빅 데이터가 많아지면서, 맵리듀스를 이용하여 조인질의를 수행하는 다양한 연구가 이루어지고 있다. 하지만 입력 데이터의 크기가 클 때 중간 생성 데이터의 크기가 커지면서 디스크의 입출력과 네트워크 트래픽의 증가로 수행시간이 오래 걸리는 문제가 있다. 본 논문에서는 맵리듀스 프레임워크를 이용한 세타 조인에 대해 중간 생성 데이터의 크기를 최대 75%를 줄일 수 있는 향상된 세타 조인방식을 제안한다. 또한 디스크 입출력에 대한 비용모델을 제안하고 이를 세타 조인 알고리즘에 적용하여 수행시간이 가장 적게 걸리는 데이터 분할 방법을 선택하도록 한다. With growing popularity of big data, there exist many works for processing join queries using Map-Reduce. However, when the size of input data becomes large, processing time of a join query tends to grow significantly since the disk I/Os and network traffics become large due to the increase of the size of intermediate data. In this paper, to process theta-join queries using a MapReduce framework, we propose an improved theta-join algorithm which reduces up to 75% with respect to the size of intermediate result. We also propose a cost model for disk I/Os and apply the cost model to our theta-join algorithm to select the partitioning for the minimum execution time.
Analysis of Range Measurement Based on MF DGNSS Infrastructures
Pyo-Woong Son,Younghoon Han,Kiyeol Seo,Tae Hyun Fang 사단법인 항법시스템학회 2022 Journal of Positioning, Navigation, and Timing Vol.11 No.4
As location-based services using the Global Navigation Satellite System (GNSS) are diversified, concerns about the vulnerability of GNSS to radio disturbance and deception are also growing. Accordingly, countries that own and operate GNSS, such as the United States, Russia, and Europe, are also developing additional navigation systems that can compensate for GNSS' weaknesses. Among them, an R-Mode system that transmits navigation signals using an infrastructure that transmits differential GNSS (DGNSS) information using signals from the medium frequency band currently in operation is being developed in Europe and Korea. Since 2020, Korea has improved four DGNSS transmission stations, including Chungju, Eocheongdo, Palmido, and Socheongdo, to transmit R-Mode signals and test navigation performance in some parts of the West Sea. In this paper, we intend to establish a testbed for measuring the distance of R-Mode signals currently being ransmitted and analyze the results. It is confirmed that the distance measurement performance varies depending on the antenna type, diurnal variation, and propagation path of the signal.
이동 통신 단말기용 외장형 폴디드 모노폴 안테나 및 내장형 인테나
손태호(Taeho Son),정영훈(YoungHoon Joung),전홍표(Hongpyo Chun) 한국정보기술학회 2004 한국정보기술학회논문지 Vol.2 No.1
In this paper, folded monopole antenna and intenna for the Korea pes handset are designed and fabricated. The handset antenna for mobile system should be both small size and good performances. The stubby antenna based on helical structure and the retractable antenna formed a quarter wavelength antenna with a helical are commonly applied in mobile phone handset. We, in this study, design folded type monopole antenna and intenna which have better performances than conventional stubby antenna. For compensation of reducing inductance by the short length, the scheme of folding wire to increase series capacitance is used. Higher gain than helical stubby can get by widened effective areas and length of antenna using folding structure. It is shown that these new type antennas have better gain and radiation patterns than helical stubby from the measurements on 1.75~1.87 ㎓ frequency ranges.