• 제목/요약/키워드: NTP

검색결과 102건 처리시간 0.112초

무인이동체 및 지상국 컴퓨터 간의 시간 정보 동기화를 위한 시스템 연구 (A Study on System for Synchronization of Multiple UAVs and Ground Control System)

  • 이원석;이운상;송형규
    • 반도체디스플레이기술학회지
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    • 제19권1호
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    • pp.11-16
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    • 2020
  • In this paper, system that includes multiple unmanned aerial vehicles (UAVs) are considered. The vehicles are equipped with a mission computer for a specific mission and equipment. The mission equipment operates based on the time of mission computer. Also, data collected by flight computer and mission computer is saved with the time of each operating system. Generally, time offset between multiple computers always exists, though the computers are connected to the Internet. When the data collected by multiple computers is combined, the time offset causes damage on reliability of the combined data. Computers that connected to the Internet are synchronized by network time protocol (NTP). This paper proposes a system that the time of multiple mission computers are synchronized by the same NTP server to minimize the time offset. In the results of the measurement, the system time offset of multiple mission computer is maintained within 10ms from the system time of the server computer.

치주염 치료를 위한 저온상압 플라즈마의 항염효과: 예비 실험 (Anti-inflammatory effect of non-thermal atmospheric pressure plasma for periodontitis treatment: in vitro pilot study)

  • 박유리;김현주;이주연;정성희;권은영;주지영
    • 구강회복응용과학지
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    • 제37권2호
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    • pp.88-94
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    • 2021
  • 목적: 대표적인 만성 구강내 염증성 질환인 치주염의 치료에 저온상압 플라즈마의 적용 가능성을 평가해 보고자, 치주 조직내 많이 분포하고 있는 치은섬유모세포에 대한 항염효과를 평가해보았다. 연구 재료 및 방법: 두명의 환자의 구강내에서 건강한 치은조직을 채득하여 primary culture 시행한 후 실험실에서 치은섬유모세포를 계대배양하였다. 세포 실험을 위해 헬륨 가스를 이용하는 저온상압 플라즈마 장치를 제작하였다. 치주염증을 유도하기 위해 Porphyromonas gingivalis (Pg)의 LPS를 처리하고, CCK-8 kit를 통해 세포생존율 평가를 시행하고 염증성 사이토카인인 interleukin (IL)-8, IL-6의 분비정도를 평가하였다. 결과: 인간치은섬유모세포 생존율 평가에서는 Pg LPS를 처리한 군과 플라즈마를 처리한 군, Pg LPS와 플라즈마를 함께 처리한 군 모두에서 생존율이 92.28%에서 100% 사이로 존재하고 통계적으로 유의성은 관찰되지 않았다. 6시간과 24시간 세포배양시간에 따른 세포생존율 차이도 관찰되지 않았다. Pg LPS를 적용하였을 때 대조군에 비해 IL-8과 6의 분비가 증가되었으며, 저온상압 플라즈마의 적용시 그 분비가 통계적으로 유의하게 감소되었다. 결론: 저온상압 플라즈마가 인간섬유모세포의 세포 생존율에 유의한 영향을 끼치지 않았고, 치주염유발 염증성 사이토카인인인 IL-8과 IL-6의 분비를 억제하였다.

스마트 팩토리 구축을 위한 프로토콜 개발 (The Development of Protocol for Construction of Smart Factory)

  • 이용민;이원복;이승호
    • 전기전자학회논문지
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    • 제23권3호
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    • pp.1096-1099
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    • 2019
  • 본 논문에서는 스마트 팩토리 구축을 위한 프로토콜을 제안한다. 제안하는 스마트 팩토리 구축을 위한 프로토콜은 OPC UA Server/Client, TSN 실시간 통신 기술, NTP & PTP 시간 동기화 프로토콜, 필드버스(Field Bus) 프로토콜 및 컨버젼 모듈, 데이터 전송지연에 대한 저장기술 및 동기화 프로토콜로 구성된다. OPC UA Server/Client 는 산업용 하드웨어 디바이스와 인터페이스 하기 위한 시스템 통합 프로토콜로써 플랫폼에 의존적이지 않고 다방면에서 사용할 수 있는 표준을 지원한다. TSN 실시간 통신 기술은 고속 네트워크 환경에서 디바이스들 간 정확한 시간을 공유함으로써 생산라인 등의 정밀한 시간관리 및 제어기술을 제공한다. NTP & PTP 시간 동기화 프로토콜은 IEEE1588 표준화 기술을 제공한다. 필드버스 프로토콜 및 컨버젼 모듈은 산업에서 주로 사용하는 프로토콜을 OPC로 변환하여 연결의 확장성을 제공한다. 데이터 전송 지연에 대한 저장기술 및 동기화 프로토콜은 데이터 전송 지연과 데이터의 손실에 대한 해결 기능을 제공한다. 제안된 스마트 팩토리 구축을 위한 프로토콜의 성능을 평가하기 위하여 시험기관에서 실험한 결과 응답시간은 0.1367ms, 동기시간은 0.404ms, 동시접속 수는 100개, 프로토콜의 연동개수 5개, 데이터 저장 및 동기화는 1,000노드로 세계최고 수준과 동일한 결과를 산출하였다.

황색고구마 퓨레의 품질과 Carotenoid색소 (Quality Properties and Carotenoid Pigments of Yellow Sweet Potato Puree)

  • 정순택;임종환;강성국
    • 한국식품영양과학회지
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    • 제27권4호
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    • pp.596-602
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    • 1998
  • Two kinds of sweet potato puree were prepared with Benihayato cultivar of yellow sweet potato with or without $\alpha$-amylase enzyme treatment. Chemical and rheological properties of enzyme-treated puree were different from those of control puree. Reducing sugar content and iodine value increased by $\alpha$-amylase enzyme treatment, while alcohol insoluble solids and viscosity decreased by enzyme treatment. However, the changes of carotenoid content were not significantly different. Hunter-b-values(yellowness) were 27.19 and 23.54 for no enzyme-treated puree(NTP) and enzyme-treated puree(ETP), respectively. Hunter-a values(redness) were 2.24 and 6.05 for NTP abd ETP, respectively. Content of total carotenoid of canned puree heated at 13$0^{\circ}C$ for 30 min decreased by 59 percents.

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정전식 집진기에서 오존, $NO_x$ 발생특성에 관한 연구 (A Study on the Characteristic of Ozone and $NO_x$ Generation in the Electerostatic Precipitators)

  • 노광철;이영호;오명도
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1423-1428
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    • 2003
  • We investigated the amount of the toxic gases emitted from the Electrostatic Precipitators(ESPs), which were currently used by indoor air cleaners. We used the wire-to-plate(WTP) type and the needle-to-plate(NTP) type corona discharger in our study. Using the voltage, the polarity of wire, the number of needles of NTP as the input variables, we studied the characteristic of Ozone and $NO_x$ generation in the ESPs. As the results, we found out that the concentration of Ozone, $NO_2$ and $NO_x$ is increased, but the amount of NO is decreased with increasing the voltage and the number of needles. And we knew that the generation rate of ozone and $NO_x$ is very related with the corona region.

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Implementation of Node Transition Probability based Routing Algorithm for MANET and Performance Analysis using Different Mobility Models

  • Radha, Sankararajan;Shanmugavel, Sethu
    • Journal of Communications and Networks
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    • 제5권3호
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    • pp.202-214
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    • 2003
  • The central challenge in the design of ad-hoc networks is the development of dynamic routing protocol that efficiently finds route between mobile nodes. Several routing protocols such as DSR, AODV and DSDV have been proposed in the literature to facilitate communication in such dynamically changing network topology. In this paper, a Node Transition Probability (NTP) based routing algorithm, which determines stable routes using the received power from all other neighboring nodes is proposed. NTP based routing algorithm is designed and implemented using Global Mobile Simulator (GloMoSim), a scalable network simulator. The performance of this routing algorithm is studied for various mobility models and throughput, control overhead, average end-to-end delay, and percentage of packet dropped are compared with the existing routing protocols. This algorithm shows acceptable performance under all mobility conditions. The results show that this algorithm maximizes the bandwidth utilization during heavy traffic with lesser overhead.

Time Management System for Applications of UAV Network

  • Lee, Won-Seok;Jang, Jun-Yong;Song, Hyoung-Kyu
    • Journal of Positioning, Navigation, and Timing
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    • 제9권4호
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    • pp.405-409
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    • 2020
  • This paper proposes time management system for unmanned aerial vehicle (UAV) network. The computers of the UAVs need time synchronization that time offset does not exceed the minimum interval of data samples for errorless data blending between the computers. The proposed time management system is composed of time synchronization and general management systems for UAV control. The systems communicate each other for time information and control signals. The synchronization system uses improved version of existing time offset estimation that network time protocol (NTP) uses. The time synchronization is operated when the time offset of any UAV exceeds threshold that preconfigured by the general management system. The demonstration of prototype shows stable time synchronization satisfying preconfigured threshold.

NMR Studies on the N-terminal Acetylation Domain of Histone H4

  • 방은정;이창훈;윤종복;청주희;이대윤;이원태
    • Bulletin of the Korean Chemical Society
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    • 제22권5호
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    • pp.507-513
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    • 2001
  • Histones, nuclear proteins that interact with DNA to form nucleosomes, are essential for both the regulation of transcription and the packaging of DNA within chromosomes. The N-terminal domain of histone H4 which contains four acetylation sites at lysines, may play a separate role in chromatin structure from the remainder of the H4 chain. NMR data suggest that H4NTP peptide does have relating disordered structure at physiological pH, however, it has a defined structure at lower pH conditions. The solution structure calculated from NMR data shows a well structured region comprising residues of Val21-Asp24. In addition, our results suggest that the H4NTP prefers an extended backbone conformation at acetylation sites, however, it (especially Lys 12 ) became more defined structures after acetylation for its optimum function.

욕창의 수술적 치료에 대한 임상적 고찰 (Clinical Considerations of the Surgical Treatments of the Pressure Sore)

  • 이근철;문주봉;권용석;차병훈;김석권
    • Archives of Plastic Surgery
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    • 제34권5호
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    • pp.574-579
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    • 2007
  • Purpose: The number of sore patients are increasing steadily, especially in old ages, chronic disease and paralytic patients. Most of patients need to surgical treatment. The aim of this paper is to assess clinical analysis of surgical treatment and to consider operative methods, complications, and recurrences.Methods: We reviewed the data from 82 consecutive patients with 101 pressure sores from March 2003 to May 2006 to discuss the occurrence rate and recurrence rate according to the site on the basis of the presence or absence of paraplegic and its etiology-the patients were categorized into three diagnostic groups: traumatic paraplegics(TP), nontraumatic paraplegics (NTP), and nontraumatic nonparaplegics(NTNP). We examined the sites and sizes of each lesions, patient's state, primary causes of pressure sore, operative methods as each sites and groups, occurrence of complications and recurrences on each groups. Results: In 82 patients, 52 patients were male, 30 patients were female. The male to female ratio was 1.7 :1. Mean age was 55.8 years. 27 patients were in TP group, 35 in NTP group, and 20 in NTNP group, respectively. The common site of sore were sacral area (50.5%), greater trochanteric area(15.8%) and ischial area(13.9%). In each group, incidence rate of recurrence and complication were 11.1%, 40.7% in TP, 5.7%, 5.7% in NTP and 15%, 45% in NTNP. Conclusion: Surgeons must consider the general condition of the patient and possibility of recurrence and returning of daily life. We propose that cutaneous flap, fasciocutaneous flap or skin graft as well as musculocutaneous flap be useful to repair of sore site as each patient's state.