• Title/Summary/Keyword: Pattern-lock

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조류 조화상수의 월변동성 완화 방법 고찰 (Investigating the Adjustment Methods of Monthly Variability in Tidal Current Harmonic Constants)

  • 변도성
    • Ocean and Polar Research
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    • 제33권3호
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    • pp.309-319
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    • 2011
  • This is a preliminary study of the feasibility of obtaining reliable tidal current harmonic constants, using one month of current observations, to verify the accuracy of a tidal model. An inference method is commonly used to separate out the tidal harmonic constituents when the available data spans less than a synodic period. In contrast to tidal constituents, studies of the separation of tidal-current harmonics are rare, basically due to a dearth of the long-term observation data needed for such experiments. We conducted concurrent and monthly harmonic analyses for tidal current velocities and heights, using 2 years (2006 and 2007) of current and sea-level records obtained from the Tidal Current Signal Station located in the narrow waterway in front of Incheon Lock, Korea. Firstly, the l-year harmonic analyses showed that, with the exception of $M_2$ and $S_2$ semidiurnal constituents, the major constituents were different for the tidal currents and heights. $K_1$, for instance, was found to be the 4th major tidal constituent but not an important tidal current constituent. Secondly, we examined monthly variation in the amplitudes and phase-lags of the $S_2$ and $K_1$ current-velocity and tide constituents over a 23-month period. The resultant patterns of variation in the amplitudes and phase-lags of the $S_2$ tidal currents and tides were similar, exhibiting a sine curve form with a 6-month period. Similarly, variation in the $K_1$ tidal constant and tidal current-velocity phase lags showed a sine curve pattern with a 6-month period. However, that of the $K_1$ tidal current-velocity amplitude showed a somewhat irregular sine curve pattern. Lastly, we investigated and tested the inference methods available for separating the $K_2$ and $S_2$ current-velocity constituents via monthly harmonic analysis. We compared the effects of reduction in monthly variability in tidal harmonic constants of the $S_2$ current-velocity constituent using three different inference methods and that of Schureman (1976). Specifically, to separate out the two constituents ($S_2$ and $K_2$), we used three different inference parameter (i.e. amplitude ratio and phase-lag diggerence) values derived from the 1-year harmonic analyses of current-velocities and tidal heights at (near) the short-term observation station and from tidal potential (TP), together with Schureman's (1976) inference (SI). Results from these four different methods reveal that TP and SI are satisfactorily applicable where results of long-term harmonic analysis are not available. We also discussed how to further reduce the monthly variability in $S_2$ tidal current-velocity constants.

VR 상에서의 안전한 PIN 입력 방법 제안 (Proposal of Safe PIN Input Method on VR)

  • 김현준;권혁동;권용빈;서화정
    • 한국정보통신학회논문지
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    • 제23권5호
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    • pp.622-629
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    • 2019
  • 가상현실 속에서 실제와 같은 서비스를 제공하는 기술 VR(Virtual Reality)은 Head Mounted Display(HMD) 기기를 이용하여 실제와 유사한 체험을 제공한다. 최근 VR의 시장은 커졌으나 가상현실에서의 보안에 대한 연구는 다른 분야에 비해 미흡하다. 현재 VR을 활용한 많은 개인화된 서비스들이 진행되고 있는 만큼 안전한 사용자 인증이 중요하다. VR의 HMD 기기를 착용을 하면 주변 환경을 인식하지 못하기에 Personal Identification Number(PIN)입력 시에 Shoulder Surfing Attack (SSA)으로 사용자의 입력 패턴을 분석이 용이하다. 본 논문에서는 사용자의 편의성은 그대로 유지하면서 해커가 입력 패턴을 분석하더라도 사용자의 비밀 번호를 안전하게 보호할 수 있는 방법에 대해 제안한다. VR 특성에 맞게 기존 직사각형 모양에서 벗어난 새로운 형태의 가상 키패드와 사용자와 직관적인 상호작용을 위해 자물쇠 오브젝트를 최초로 구현 하였다. 또한 VR의 기존 입력 장치들과 동일한 센서를 사용하는 스마트 글러브와 이에 적합한 회전방식의 PIN입력 방식을 구현하였다. 따라서 총 세 가지의 VR 상에서의 안전한 PIN 입력 방법에 대하여 제안하며 실험을 통해 SSA에 대한 안전성을 검증하였다.

역도 인상동작의 운동학적 분석 (A Kinematic Analysis of Snatch Technique in Weight-Lifting)

  • 문영진;송주호;김지섭
    • 한국운동역학회지
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    • 제14권2호
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    • pp.41-55
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    • 2004
  • This study analyzed snatch technique in weight-lifting performed by female gold, silver, and copper medalists at the 75kg level in the 2002 Pusan Asian Games and obtained the following conclusions. 1. KSH used more extensor in the waist than those in ankles, knees, or hip joints during the second pull, So further training is required to manifest both each of joints and waist extensor effectively and thus for the line from shoulders through barbell to hip joints to form a smooth vertical pattern. 2. Contrary to those in other countries, Korean athlete KSH tended to be swift in starting but slow in the second pull section, showing less effectiveness in movement during the second pull; therefore, they must try to exert a swift movement in lockout. 3. KSH showed slowdown in the speed, which was a factor interfering with performance during second pull, despite the great maximum speed of moving barbell. It is important to use barbell sufficiently not to reduce the speed of vertical movement but rather to keep the speed increasing. 4. KSH, who kept doing inefficient movements such as failure to perform swift lockout after lifting the heel at the maximum angle of lower limbs, needs to reduce this meaningless extension of ankles, knees, or hip joints to exert energy effectively.

전단간섭계와 적외선열화상을 이용한 감육 직관의 결함검출 (Defect Detection of Wall Thinned Straight Pipe using Shearography and Lock-in Infrared Thermography)

  • 김경석;정현철;장호섭;김하식;나성원
    • 한국정밀공학회지
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    • 제26권11호
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    • pp.55-61
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    • 2009
  • The wall thinning defect of nuclear power pipe is mainly occurred by the affect of the flow accelerated corrosion (FAC) of fluid. This type of defect becomes the cause of damage or destruction of in carbon steel pipes. Therefore, it is very important to measure defect which is existed not only on the welding part but also on the whole field of pipe. This study use dual-beam Shearography, which can measure the out-of-plane deformation and the in-plane deformation by using another illuminated laser beam and simple image processing technique. And this study proposes Infrared thermography, which is a two-dimensional non-contact nondestructive evaluation that can detect internal defects from the thermal distribution by the inspection of infrared light radiated from the object surface. In this paper, defect of nuclear power pipe were, measured using dual-beam shearography and infrared thermography, quantitatively evaluated by the analysis of phase map and thermal image pattern.

A novel approach of ship wakes target classification based on the LBP-IBPANN algorithm

  • Bo, Liu;Yan, Lin;Liang, Zhang
    • Ocean Systems Engineering
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    • 제4권1호
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    • pp.53-62
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    • 2014
  • The detection of ship wakes image can demonstrate substantial information regarding on a ship, such as its tonnage, type, direction, and speed of movement. Consequently, the wake target recognition is a favorable way for ship identification. This paper proposes a Local Binary Pattern (LBP) approach to extract image features (wakes) for training an Improved Back Propagation Artificial Neural Network (IBPANN) to identify ship speed. This method is applied to sort and recognize the ship wakes of five different speeds images, the result shows that the detection accuracy is satisfied as expected, the average correctness rates of wakes target recognition at the five speeds may be achieved over 80%. Specifically, the lower ship's speed, the better accurate rate, sometimes it's accuracy could be close to 100%. In addition, one significant feature of this method is that it can receive a higher recognition rate than the nearest neighbor classification method.

직교격자를 이용한 단순 세장 구조물의 와유기 진동 해석 (Vortex-Induced Vibration of Simple Slender Structure Using Cartesian Mesh)

  • 한명륜;안형택
    • 대한조선학회논문집
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    • 제48권3호
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    • pp.260-266
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    • 2011
  • For long slender offshore structures, such as cables and pipe lines, their interaction with surrounding fluid flow becomes an important issue for global design of ocean systems. We employ a long circular cylinder as a representative case of slender offshore structure. A flexibly mounted cylinder in cross-flow generates complex vortex shedding and results in oscillation of the structure. In this paper, flow behind a circular cylinder at Re=100 is simulated. The vortex shedding pattern and flow induced motion are examined in the cross flow configuration as well as with various yaw-angled configurations. The "Lock-in" phenomenon is also observed when reduced velocity is approximately 4.0. The MAC Grid system, which is the typical grid system for Cartesian mesh and pressure correction methods, are used for solving the incompressible Navier-Stokes equations. Predictor/Corrector method is applied for obtaining a non-linear response of structure at the flexibly mounted. The existance and motion of the body is represented by the immersed boundary technique.

스마트 폰 잠금 해제 과정에서의 감성적 UX 요소가 전반적 기기 사용 경험과 향후 사용 의도에 미치는 영향 (The Effect of an Emotional Factor on User Experience with Smartphone Unlocking Process)

  • 이선화;신영수;임채린;백한나;이성호;김진우
    • 감성과학
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    • 제17권4호
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    • pp.79-88
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    • 2014
  • 스마트폰의 발전에 따라, 오늘날의 현대인들은 인터넷 뱅킹이나 결제, 금융, 상거래에 이르기까지 생활의 많은 업무들을 스마트폰을 통해 해결하고 있다. 그러나 다른 한편으로는 이러한 스마트폰의 유실에 따른 개인정보 유출 문제가 대두되면서, 사용자들의 불안감 또한 그 어느 때보다 높아지고 있다. 이와 같은 배경 하에, 최근에는 스마트 기기의 잠금장치와 관련한 다양한 보안 시스템 및 기술들이 활발히 개발되고 있는 상황이다. 그러나 잠금장치와 같은 보안기능들은 역설적이게도 사용자들에게 잠금 해제 과정에서의 번거로움과 불편함을 제공하게 된다. 이는 곧 사용자의 편리한 사용이라는 가치와 기기 내 저장 정보 자체의 안전한 유지라는 가치 사이의 상반 관계를 의미하게 된다. 따라서 해당 연구에서는 잠금 해제 과정에서의 안전함과 편리성 사이의 상반 관계를 극복할 수 있는 방법으로 '자기은폐성'이라는 개념을 적용하고자 하였다. 또한, 이에 기반을 둔 실험을 통하여, 스마트폰 사용 경험과 향후 사용의도에 대한 측정도 시도하고자 하였다. 결과적으로, 자기은폐성이 적용된 보안기능은 스마트폰 사용 경험에는 부정적인 영향을 주는 반면, 향후 스마트폰 사용 의도에는 긍정적인 영향을 주는 것으로 나타났다. 이를 통해, 본 연구는 궁극적으로 스마트 기기의 잠금 해제 과정에서 보다 최적의 경험을 제공할 수 있는 새로운 사용자 경험 디자인 요소를 제시하고자 한다.

A 1.248 Gb/s - 2.918 Gb/s Low-Power Receiver for MIPI-DigRF M-PHY with a Fast Settling Fully Digital Frequency Detection Loop in 0.11 ㎛ CMOS

  • Kim, Sang-Yun;Lee, Juri;Park, Hyung-Gu;Pu, Young Gun;Lee, Jae Yong;Lee, Kang-Yoon
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제15권4호
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    • pp.506-517
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    • 2015
  • This paper presents a 1.248 Gb/s - 2.918 Gb/s low-power receiver MIPI-DigRF M-PHY with a fully digital frequency detection loop. MIPI-DigRF M-PHY should be operated in a very short training time which is $0.01{\mu}s$ the for HS-G2B mode. Because of this short SYNC pattern, clock and data recovery (CDR) should have extremely fast locking time. Thus, the quarter rate CDR with a fully digital frequency detection loop is proposed to implement a fast phase tracking loop. Also, a low power CDR architecture, deserializer and voltage controlled oscillator (VCO) are proposed to meet the low power requirement of MIPI-DigRF M-PHY. This chip is fabricated using a $0.11{\mu}m$ CMOS process, and the die area is $600{\mu}m{\times}250{\mu}m$. The power consumption of the receiver is 16 mW from the supply voltage of 1.1 V. The measured lock time of the CDR is less than 20 ns. The measured rms and peak jitter are $35.24ps_{p-p}$ and $4.25ps_{rms}$ respectively for HS-G2 mode.

고려시대 가구재료 연구 (A Study on the Material of Furniture in Goryeo)

  • 조숙경
    • 한국가구학회지
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    • 제25권1호
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    • pp.19-27
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    • 2014
  • This paper studied the materials of the furniture which the noble men used in Goryeo, based on the furniture material category of solid wood furniture, lacquerware inlaid with mother-of-pearl and hardware. As for the solid wood furniture, the wood and furniture types are inferred based on the documents. The trees used for the wood furniture were zelkova, korean willow, pine, royal paulownia, maidenhair tree, korean pine, chinese juniper and elm. The furniture types were table, chair, wooden bench, small portable table, writing table, and folding screen. As to the types of lacquerware inlaid with mother-of-pearl, most of them were hams with top, which were made of abalone shells. The features of the lacquerware inlaid with mother-of-pearl were in detail and elaborate like the pattern of the full bloomed chrysanthemum. Writing tables were also made of lacquerware as pieces of furniture. Distinctively, the mother-of-pearl furniture material was popular enough to be used even in a horse saddle. Regarding the metal feldspar used as both a practical use and decoration, there are drop handle, hinge, the front basis, and lock seen in the artifacts, which were made of cast iron, bronze, and brass. Their manufacture techniques were eojamoon, bratticing and sheet metal. Through this study of the furniture materials used in Goryeo, it seems that Goryeo furniture focused on the functions rather than on the decorations, and in turn the forms were simple and basic. The technique of mother-of-pearl, a bit elaborate one, was used in the props furniture like kitchen wares, hams, or writing talbes. Probably, the solid wood is inferred to be used in a low wooden bench, a chair, and a table based on the documents.

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여행 브랜드를 위한 콘텐츠 마케팅 연구 -여행 영상 형태의 유튜브 Vlog를 중심으로- (A Study on Content Marketing for Travel Brand Focus on Youtube Vlog Formed Travel Video -)

  • 조장환;박보람
    • 디지털융복합연구
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    • 제17권12호
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    • pp.445-450
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    • 2019
  • 본 연구는 검색엔진으로 진화하고 있는 유튜브의 여행 Vlog에 대한 시청패턴과 콘텐츠 니즈를 파악하는 데 목적이 있다. 일차적으로 설문 지법을 사용하여 45명을 대상으로 사전 조사를 진행하였고, 이차적으로 이를 통해 얻은 결괏값을 바탕으로 Creating Pleasurable Interfaces 모형을 활용하여 심층 면담을 진행하였다. 그 결과, 첫 번째로 시청자는 여행 Vlog를 활용하여 단편적인 정보보다는 여행에 관련된 전반적인 정보를 얻고 있었다. 두 번째로 유튜브에 업로드된 여행 Vlog의 절대량이 부족하여 시청자가 원하는 정보를 얻는데 물리적인 어려움이 있었다. 세 번째로 여행 Vlog를 활용한 마케팅이 대중 매체의 광고 형식에서 벗어나지 못해 콘텐츠 전반에 서비스나 제품 노출에 일관성이 부족하다는 문제점이 도출되었다. 본 연구를 바탕으로 도출된 결과는 여행 관련 기업의 콘텐츠 마케팅 전략에 있어서 인사이트를 제공하고 크리에이터들에게 콘텐츠 제작에 실질적인 도움을 줄 수 있으리라 기대된다.