실내측위를 위한 새로운 클락 동기 방안

이영규,양성훈,이승우,이창복,김영범,최성수,Lee, Young-Kyu,Yang, Sung-Hoon,Lee, Seong-Woo,Lee, Chang-Bok,Kim, Young-Beom,Choe, Seong-Su 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.3A

클락 동기는 실내 측위를 위한 실내 동기망을 구축하는데 있어서 가장 기본적으로 고려해야할 요소 중 하나이다. 본 논문에서는 하드웨어의 복잡성 및 동기에 필요한 데이터 오버헤드를 줄이기 위해 타임스탬프를 사용하지 않고 클락을 동기 시키기 위한 새로운 알고리즘에 대해서 논한다. 또한 동기 성능에 큰 영향을 미치는 주파수 드리프트를 보상해 주기 위한 알고리즘에 대해서도 기술한다. 제안한 동기 알고리즘을 사용한 동기 성능에 대한 평가는 모의실험을 통한 MTIE(Maximum Time Interval Error) 값을 고찰함으로써 이루어졌다. 모의실험에 있어서 실제적인 오실레이터에 대한 주파수 드리프트 값을 사용하였다. 모의실험 결과 1 초의 동기 간격에 1 ns 분해능을 갖고 주 클락과 종속 클락에 TCXO를 사용하면 10 ns 이하의 동기가 가능함을 고찰하였다. Clock Synchronization is one of the most basic factors to be considered when we implement an indoor synchronization network for indoor positioning. In this paper, we present a new synchronization algorithm which does not employ time stamps in order to reduce the hardware complexity and data overhead. In addition to that, we describe an algorithm that is designed to compensate the frequency drift giving an serious impact on the synchronization performance. The performance evaluation of the proposed algorithm is achieved by investigating MTIE (Maximum Time Interval Error) values through simulations. In the simulations, the frequency drift values of the practical oscillators are used. From the simulation results, it is investigated that we can achieve the synchronization performance under 10 ns when we use 1 second synchronization interval with 1 ns resolution and TCXOs (Tmperature Compensated Cristal Oscillators) both in the master clock and the slave clock.

국내의 지역별 우박 발생 빈도 분석

이영규,이재수,이승수,김학선,Lee. Young-Kyu,Lee. Jae-Soo,Lee. Sung-Su,Kim. Hak-Sun 한국방재학회 2007 한국방재학회 학술발표대회논문집 Vol.2007 No.1

Data for occurrence of hail over Korean Peninsula for the period 1961-2005 are obtained from the Korea Meteorological Administration (KMA). According to the average occurrences during each season in Korea Peninsular, hail days are almost distributed uniformly in the spring, fall and winter, except the summer and have averages of 5 days for each season. Analysis of regional occurrence of hail shows that inland of Korea Peninsular is vulnerable to hail in the spring and summer and the islands of Ullung, Baegryeong and Cheju and the coastal regions vulnerable in the fall and winter. It can be postulated that these seasonal patterns of hail is affected by the Monsoon effect.

고령자 남녀와 20대 남녀에 있어서 다양한 등속수축중 최대 모멘트의 비교

金智源(Ji-Won Kim),金相佑(Sang-Woo Kim),文基旭(Ki-Wook Moon),嚴光文(Gwang-Moon Eom),李泳揆(Young-Gyu Lee),南貞淑(Jung-Sook Nam),朴寬龍(Kwan-Yong Park),金耀翰(Yo-Han Kim),洪廷和(Jeong-Hwa Hong),朴炳奎(Bung-Kyu Park) 대한전기학회 2008 전기학회논문지 Vol.57 No.10

In this paper, we investigated the maximum ankle joint plantarflexion moment (MPM) of young and elderly subjects during various modes of isokinetic contractions with special interest in the elderly females who were reported to have higher fall rate than the elderly males. Subjects include the young subjects (14 males: 22.7±2.5yrs, 13 females: 20.5±1.3yrs) and the elderly subjects (17 males: 65.8±10.5yrs, 26 females: 71.4±5.2yrs). The MPM was normalized by each subject's body weight. The MPM of elderly females was the weakest among the groups, particularly, at the eccentric contractions. The male-to-female ratio of MPM was greater in the elderly than in the young and the young-to-elderly ratio of MPM was greater in female than in male, both during the eccentric contractions. The result suggests that the decreased muscle force per body weight, especially at the eccentric contraction, may be one reason for the more frequent fall of the elderly female than the elderly male.

UFIR 필터 Ladder 알고리즘 이용 GPS Holdover 성능 추정

이영규,양성훈,이창복,허문범,Lee, Young-kyu,Yang, Sung-hoon,Lee, Chang-bok,Heo, Moon-beom 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.7

In this paper, we described the simulation results of the phase offset performance of a clock in holdover mode which was normally operated in GPS Disciplined Oscillator (GPSDO). In the TIE model, we included the time error term caused by environmental temperature variation because one of the most important parameters of clock phase error is the frequency offset and drift caused by the variation of temperature. For the simulation, we employed Maximum Time Interval Error (MTIE) for the performance evaluation when the frequency offset and drift are estimated by using an Unbiased Finite Impulse Response (UFIR) filter with ladder algorithm. We assumed that the noise in the GPS measurement is white Gaussian with zero mean and 1 ns standard deviation, and temperature linearly varies with a slope of $1{^{\circ}C}$ per hour. From the simulation results, the followings were observed. First, with the estimation error of temperature of less than 3 % and the temperature compensation period of less than 900 seconds, the requirement of CDMA2000 phase synchronization under 10 us could be achieved for more than 40,000 seconds holdover time if we employ an OCXO (Oven Controlled Crystal Oscillator) clock. Second, in order to achieve the requirement of LTE-TDD under 1.5 us for more than 10,000 seconds holdover time, below 3 % estimation error and 500 seconds should be retained if a Rubidium clock is adopted.

PGSFR 제어봉집합체 낙하성능시험

이영규,김회웅,이재한,구경회,김종범,김성균,Lee, Young Kyu,Kim, Hoe Woong,Lee, Jae Han,Koo, Gyeong Hoi,Kim, Jong Bum,Kim, Sung Kyun 한국압력기기공학회 2016 한국압력기기공학회 논문집 Vol.12 No.1

The Control Rod Assembly (CRA) controls the reactor power by adjusting its position in the reactor core during normal operation and should be quickly inserted into the reactor core by free drop under scram condition to shut down chain reactions. Therefore, the drop time of the CRA is one of important factors for the safety of the nuclear reactor and must be experimentally verified. This study presents the drop performance test of the CRA which has been conceptually designed for the Proto-type Generation IV Sodium-cooled Fast Reactor. During the test, the CRA was free dropped from a height of 1 m under different flow rate conditions and its drop time was measured. The results showed that the drop time of the CRA increased as the flow rate increased; the average drop times of the CRA were approximately 1.527 seconds, 1.599 seconds and 1.676 seconds at 0%, 100% and 200% of design flow rates, respectively.

기술사마당_기술자료 - 해수담수화설비의 전처리방안에서 Beach Well Intake 방법의 적용성 검토

이영규,Lee, Young-Kyu 한국기술사회 2009 技術士 Vol.42 No.6

According to increasing demand of water mainly due to the growth of population and increased water consumption, many countries either face or worry about the shortage of fresh water. Proportionately, importance and efforts of each country to develop the potable water has been gradually increasing as well. Among others, desalination of seawater has been developed to one of the solutions mainly from the middle east and other arid regions to produce large quantity of fresh water from seawater. We installed beach seawater collector wells to develop the filtered seawater supply for desalination in a refinery. We came to a conclusion that the beach seawater collector well is one of the recommendable alternatives of seawater pre-treatment for desalination applications with lower operating cost and higher efficiency.

Au 스터드 범프와 Sn-3.5Ag 솔더범프로 플립칩 본딩된 접합부의 미세조직 및 기계적 특성

이영규,고용호,유세훈,이창우,Lee, Young-Kyu,Ko, Yong-Ho,Yoo, Se-Hoon,Lee, Chang-Woo 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.6

The effect of flip chip bonding parameters on formation of intermetallic compounds (IMCs) between Au stud bumps and Sn-3.5Ag solder was investigated. In this study, flip chip bonding temperature was performed at $260^{\circ}C$ and $300^{\circ}C$ with various bonding times of 5, 10, and 20 sec. AuSn, $AuSn_2$ and $AuSn_4$ IMCs were formed at the interface of joints and (Au, Cu)$_6Sn_5$ IMC was observed near Cu pad side in the joint. At bonding temperature of $260^{\circ}C$, $AuSn_4$ IMC was dominant in the joint compared to other Au-Sn IMCs as bonding time increased. At bonding temperature of $300^{\circ}C$, $AuSn_2$ IMC clusters, which were surrounded by $AuSn_4$ IMC, were observed in the solder joint due to fast diffusivity of Au to molten solder with increased bonding temperature. Bond strength of Au stud bump joined with Sn-3.5Ag solder was about 23 gf/bump and fracture mode of the joint was intergranular fracture between $AuSn_2$ and $AuSn_4$ IMCs regardless bonding conditions.

정밀 시각 프로토콜 동기 성능 평가

이영규(Young-kyu Lee),양성훈(Sung-hoon Yang),이창복(Chang-bok Lee),이종구(Jong-Goo Lee),박영미(Young-Mi Park),이문석(Moon-Seok Lee) 제어로봇시스템학회 2014 제어·로봇·시스템학회 논문지 Vol.20 No.6

In this paper, we described the investigated theoretical time synchronization performances and experiment results obtained by commercially provided PTP (Precise Time Protocol) modules when the time of a slave clock is synchronized to the master clock. In the case of the theoretical performance analysis, we investigated 3 types of clock levels such as Crystal Oscillator (XO), TCXO (Temperature Compensated XO) and OCXO (Oven Controlled XO). From the analysis, it was observed that the synchronization performance is greatly influenced by the synchronization period and the required performance under 1 us can be achieved by using XO level clocks when the synchronization period is less than 2 seconds and the uncertainty of the propagation delay is under 100 ns. For the experiments using commercial PTP modules, the synchronization performance was investigated for direct, through 1 hub and through 2 hubs connections between the master clock and the slave clock. From the experiment results, we observed that time synchronization under 90 ns with 1,000 seconds observation interval can be achieved in the case of direct connection.

공간정보를 활용한 저수지 사고 범람위험지도 작성기법 개발

이영규(Young Kyu Lee),이승수(Sungsu Lee),김형수(Hung Soo Kim),함희정(Hee Jung Ham),정종원(Jongwon Jung) 위기관리 이론과 실천 2020 Crisisonomy Vol.16 No.7

현행 저수지 안전관리 관점은 사고율 관리에 방점이 찍혀 있다. 이런 관점은 저수지 사고를 최소화할수 있다는 장점을 가지나 인명과 재산 피해를 효율적으로 관리할 수 없다는 약점을 갖는다. 저수지사고로 인한 인명과 재산 피해를 최소화하기 위해서는 사회 리스크 관리 관점으로 패러다임 전환이필요하다. 사회 리스크 관리 관점에서 전수 저수지를 관리하기 위해서는 전수 저수지의 피해규모추정이 가능토록 기술이 뒷받침해줘야 한다. 특히 전수 저수지에 적용가능한 범람위험지도 작성기법이 뒷받침해줄 수 있어야 한다. 본 연구에서는 전수 저수지의 범람위험지도 작성을 지원하기 위해서공간정보를 활용한 범람위험지도 작성기법을 개발했다. 본 연구의 작성기법을 적용한 범람위험지도는 과거 저수지 사고시 침수흔적이 있는 사례와 비교를 통하여 사용가능성을 검증하였다. 또한 경북경주시 382 개소 전수 저수지의 범람위험지도 작성에 6시간 27분이 소요되었으며, 경북 영천시 826개소 전수 저수지에 9시간 45분이 소요되는 것을 보여, 본 연구 성과가 실무에 적용가능함을 보였다. The current approach to reservoir safety management in South Korea mainly focuses on reducing failure rates. This approach may help minimizing failure incidents, but fail to efficiently manage risk to life and property. To minimize the losses from potential incidents in reservoirs, the paradigm shift to the social risk management would be needed. For a more effective reservoir management from the perspective of social risk management, an accurate prediction and illustration of the consequences from the failures is critical, such as spatial mapping of inundation hazards due to reservoir failure. In this study, we developed the mapping tool illustrating dam-break inundation hazards using spatial data to support the new paradigm. The inundation hazard maps were found applicable in practice according to the comparation with the historic failures. Its practical effectiveness was also confirmed because it took only several hours to create hazard maps for hundreds of reservoirs.

산업 현장 적용을 위한 다기능 통신 중계 장치

이영규(Lee Young Kyu),김영범(Kim Young Beom),서재갑(Suh Jae Gap),홍봉조(Bong Jo Hong),김헌록(Heon Rock Kim) 한국통신학회 2007 한국통신학회 학술대회논문집 Vol.2007 No.11