• Title/Summary/Keyword: 박윤기

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A Simulation Program for the Braking Characteristics of 8$\times$4 Vehicles (8$\times$4 차량의 제동특성 시뮬레이션 프로그램 개발)

  • 서명원;박윤기;권성진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.119-128
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    • 2001
  • Recently safety systems for the commercial vehicle have been rapidly developed. However, we still have many problems in the vehicle stability and the braking performance. Especially, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and the road is wet or slippery. To design the air brake system for commercial vehicles, since the air brake system has many design variables, there must have been intensive researches on a method how to prevent dynamic instability and how to maximize the vehicle deceleration. In this study, mathematical models about an 8$\times$4 vehicle and an air brake system including an ABS controller have been constructed for computer simulation. Also, simple examples are applied to show the usefulness of the computer program. Designers can use this simulation program for understanding the braking characteristics of 8$\times$4 commercial vehicles such as trajectory, braking distance, longitudinal deceleration, lateral deceleration, and yaw rate on various road conditions.

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An Experimental Study on the Performance Improvement of an R32 Inverter Heat Pump System (R32 인버터 히트펌프 시스템의 성능향상에 관한 실험적 연구)

  • Park, Yun Ki;Ha, Man Yeoung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.11
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    • pp.547-552
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    • 2014
  • As global warming in recent years has raised ever more critical concern, refrigerants with high global warming potentials (GWP) are facing the challenge of being phased out. R410A, with a GWP of 2,088, has been widely used in residential air-conditioning and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. The present study presents experimental results of an inverter heat pump system that uses R32 as an alternative refrigerant to R410A. Drop-in tests with R32 indicated that the energy efficiency ratio of the system increased by 5.3% in cooling standard mode, and by 4.2% in heating standard mode at the same capacity; and that the cooling and heating capacity increased by about 12% at the same compressor operating frequency, while the annual performance factor (APF) of the system increased by 5.3%.

Development of the Automatic Design Program for Scaffolding System of the Membrane LNG Carrier (멤브레인 LNG 운반선용 스카폴딩 시스템의 자동 설계 프로그램 개발)

  • Lee, Hee-Tae;Shin, Sang-Beom;Park, Yun-Ki
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.2
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    • pp.233-241
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    • 2010
  • Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

A Manufacturing Process Model of Internet of Things Devices Using a PCB-mounted RFID Tag Chip (PCB 부착형 RFID 태그 칩을 이용한 사물인터넷 디바이스 생산 공정에 대한 모델)

  • Park, Yungi;Seo, Jeongwook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.674-675
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    • 2016
  • In this paper, we propose a manufacturing process model of Internet of Things devices using a Printed Circuit Board (PCB)-mounted RFID tag chip for reducing electronic wastes. Electrical and electronic products require a PCB surface mount and many examination. Also, conventional barcode systems cannot provide traceability management in PCB manufacturing before finishing Surface Mount Technology (SMT) process. The proposed process model does not require workers' attaching and detaching process unlike barcode systems. Also, RFID tag chip can record all the data in manufacturing steps. Thus, the number of connections to a database management system (DBMS) can be reduced.

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The Effectiveness of Joint Mobilization and Myofascial Release on the Neck (관절가동기법과 근막이완기법이 경부에 미치는 영향)

  • Park, Youn-Ki;Hyun, Sang-Wook;Seo, Hyun-Kyu
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.15 no.2
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    • pp.69-79
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    • 2009
  • Purpose : to investigate the effectiveness of joint mobilization and myofascial release on the neck pain and to provide the effective treatment. Methods : Twenty-two subjects with neck pain participated in the experiment. All subjects were randomly assigned to a joint mobilization group(n=11) or a myofascial release group(n=11). Both groups received treatment for 15 minutes four times during 2 weeks. Cervical range of motion(CROM) instrument was used to measure range of neck motion, and Algometer was used to measure tenderness. All measurements of the subjects were measured at pre-treatment and post-treatment. Results : 1. The range of neck right side-bending motion of the myofascial release group was significantly increased(P<0.05), and the range of neck extension, right side-bending, left side-bending, right rotation motion of the joint mobilization group was significantly increased(P<0.05). 2. There was no significant improvement of tenderness in both groups(p>0.05). Conclusion : These data suggest that joint mobilization is more effective against increasing the range of motion than myofascial release, but myofascial release is more beneficial to tenderness than joint mobilization although it does not have a significant difference in the tenderness because there was a little improvement.

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The Study of Vertebral Palpation (척추부 촉진에 관한 연구)

  • Park, Youn-Ki
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.16 no.1
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    • pp.57-63
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    • 2010
  • The palpation of spinous process and transverse process of vertebra are important part of the assesment and treatment from Orthopedic manual therapy. But the palpation area is descriptive differently each of literatures. So we generally got these outcomes. : There are C2, C3, C4 and C6 process as a bony landmarks and these are important part of establish the precise location of pain appears from cervical spine. Even though C7 process regard a prominent part, it is hard to distinguish C6 and process of T1. Thru that differentiation, grab the patient's forehead and try them cervical and hyper-extension check any movement of process or put on the fingers on C7 preocess and check the movement. The palpation of thoracic spine process is the land mark which determines general level orientation in the spine easily, there are T2, T7 spinous process. However, It is depends on how do you test the patient's arm when you palpate it and it can effect on spinous process. The transverse process of C1 is the only spot for palpation in cervical spine, and T1-3, T12 transverse process can palpate it when it stands on the process. The end of T4-6, T11 is placed on middle on vertebra of transverse process and transverse process. T7-9, T10 transverse process is place on same position as spinous process which is upper part of the spine.

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Screening of High-Palatability Rice Resources and Assessment of Eating Quality Traits of Korean Landraces and Weedy Rice Germplasms (우리나라 재래벼와 잡초벼의 식미 특성 평가 및 고식미 우수자원 탐색)

  • Kim, Choon-Song;Park, Hyun-Su;Baek, Man-Kee;Jeong, Jong-Min;Kim, Suk-Man;Park, Seul-Gi;Suh, Jung-Pil;Lee, Keon-Mi;Lee, Chang-Min;Cho, Young-Chan
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.4
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    • pp.299-310
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    • 2019
  • The eating quality of rice is one of the main concerns of rice breeding programs in many countries, especially in japonica rice cultivation areas. To select new resources with high eating quality from Korean native japonica rice, we evaluated a total of 76 varieties, including 47 native rice resources (26 landraces + 21 weedy rice) of Korea. In this study, all eating quality traits varied widely among the native resources, and some of the native resources revealed a high evaluation score in the palatability, expected eating quality, and physicochemical traits among the tested whole-plant materials. From the results, we selected two landraces (Sangdo and Waebyeo) and three weedy rice varieties (Hoengseongaengmi3, Namjejuaengmi6, and Wandoaengmi6) as promising resources for improvement of rice eating quality. Specifically, Wandoaengmi6 presented potential as a key breeding material for improving the eating quality of Korean rice cultivars, having the best evaluation results in palatability score (PS 0.83) from the sensory test and glossiness value (GV 81.8) from the Toyo taste meter of cooked rice. Given the urgent need to overcome the constraint of the narrow genetic background of Korean japonica rice, the results could be a practical solution for exploring new opportunities for improving rice eating quality through the expansion of genetic resources.

Performance Analysis of Modified TCP/IP for Realtime Control Data Transmission over IEEE-1394 Network (실시간 제어 데이터통신을 위한 IEEE-1394용 수정 TCP/IP의 성능분석)

  • 윤기중;박재현;염복진
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.2
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    • pp.197-203
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    • 2004
  • A real-time network in a distributed control system plays an important role for the reliable data transmission. Compared to the field-buses used in the past, TCP/IP protocol on the top of Ethered provides a compatibility between applications as well as an economical method to develop softwares. This paper proposes a modified TCP/IP structure for IEEE-1394 network, with which asynchronous and isochronous data transmission is selectively used for the real-time data transmission in a distributed control system. This paper also shows the performance of the proposed protocol by experiments.

Trends of DRM Technology (DRM 기술 동향)

  • Park, Ji-Hyeon;Jeong, Yeon-Jeong;Yun, Gi-Song
    • Electronics and Telecommunications Trends
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    • v.22 no.4 s.106
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    • pp.118-132
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    • 2007
  • 최근 들어 새로운 형태의 디지털 콘텐츠 관련 시장과 기술 분야가 등장하고 컨버전스나 통방 융합과 같은 흐름에 따라 기존의 산업에 많은 변화가 가해지고 있는데, 이는 기존의 산업에 대한 국외 선도 업체들의 영향력이 약화되고 있음을 의미하고, 새로운 산업 형태에 대해 기술과 표준에 대한 주도권을 확보하기 위한 경쟁이 심화됨을 의미한다. DRM 기술 관련 분야에서도 이러한 현상이 나타나고 있는데, 향후 가장 큰 시장으로 예상되는 디지털 홈 관련 DRM 기술 분야에서 이미 여러 업체 및 표준화 단체를 중심으로 주도권 경쟁을 하고 있다. 본 고에서는 디지털 홈 환경에서의 콘텐츠 보호를 위한 DRM 요소 기술에 대하여 살펴보고, 각 요소 기술 분야에서 강점을 보이는 주요 DRM 기술들에 대하여 설명한다.

Properties of the $(La_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$ Based Electrolyte for Solid Oxide Fuel Cell (고체산화물 연료전지 $(La_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$계 전해질의 제조 및 특성평가)

  • 박상선;이미재;윤기현;최병현
    • 한국전기화학회:학술대회논문집
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    • 2002.07a
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    • pp.271-276
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    • 2002
  • 고체산화물 연료전지의 구성요소인 전해질의 $(La_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$계의 결정상 및 미세구조특성을 연구하였다. Mg의 첨가량이 증가할수록 Sr의 고용량도 증가하였으며 Sr의 함량이 많으면 2차상인 $LaSrGa_3O_7$상이 생성되었으며 Mg의 첨가량이 증가함에 따라서는 $LaSrGaO_4$상이 생성되었다. $LaSrGaO_4$상이 생성된 경우에는 낮은 전도도를 나타내었으며 $LaSrGa_3O_7$상의 경우에는 전기전도도에 큰 영향을 미치지 않았다. 또한 Sr과 Mg 첨가량의 증가는 grain 성장을 억제하였으며 $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$$1000^{\circ}C$에서 0.1S/cm 정도의 전기전도도를 나타내었다.

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