• Title/Summary/Keyword: Pattern-lock

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

  • Byun, Do-Seong
    • Ocean and Polar Research
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    • v.33 no.3
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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.

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

  • Kim, Hyun-jun;Kwon, Hyeok-dong;Kwon, Yong-bin;Seo, Hwa-jeong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.5
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    • pp.622-629
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    • 2019
  • VR(Virtual Reality), which provides realistic services in virtual reality, provides a similar experience using a Head Mounted Display(HMD) device. When the HMD device is worn, it can not recognize the surrounding environment and it is easy to analyze the input pattern of the user with the Shoulder Surfing Attack(SSA) when entering the Personal Identification Number(PIN). In this paper, we propose a method to safeguard the user's password even if the hacker analyzes the input pattern while maintaining the user's convenience. For the first time, we implemented a new type of virtual keypad that deviates from the existing rectangle shape according to the VR characteristics and implemented the lock object for intuitive interaction with the user. In addition, a smart glove using the same sensor as the existing input devices of the VR and a PIN input method suitable for the rotary type are implemented and the safety of the SSA is verified through experiments.

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

  • Moon, Young-Jin;Song, Joo-Ho;Kim, Ji-Seob
    • Korean Journal of Applied Biomechanics
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    • v.14 no.2
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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.

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

  • Kim, Kyeong-Suk;Jung, Hyun-Chul;Chang, Ho-Seob;Kim, Ha-Sig;La, Sung-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.11
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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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    • v.4 no.1
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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.

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

  • Han, Myung-Ryoon;Ahn, Hyung-Teak
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.3
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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.

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

  • Lee, Sunhwa;Shin, Youngsoo;Im, Chaerin;Beak, Hannah;Lee, Sungho;Kim, Jinwoo
    • Science of Emotion and Sensibility
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    • v.17 no.4
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    • pp.79-88
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    • 2014
  • Smart-phones have become a vital part of our lives, paying a bill online, shopping using applications, using email and office applications. Therefore, the risk of the leakage of personal informations and the misuse of them becomes high, for the cost of loosing smart-phone. Many types of smart-phone security features such as password, slide-lock, and pattern lock have been introduced. However, those security locks make users not to easily access and use a smart-phone. There is tradeoff between security on one hand, and usability and cost on the other. This paper propose Self-Concealment to solve the tradeoff problem and demonstrate the effect through the experiment. In sum, Self-Concealment lowers smart-phone experience; however increases smart-phone use intension. This paper has implication for proposing new User Experience (UX) construct to resolve the trade-off between security and usability.

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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    • v.15 no.4
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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.

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

  • Cho, Sook-Kyung
    • Journal of the Korea Furniture Society
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    • v.25 no.1
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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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A Study on Content Marketing for Travel Brand Focus on Youtube Vlog Formed Travel Video - (여행 브랜드를 위한 콘텐츠 마케팅 연구 -여행 영상 형태의 유튜브 Vlog를 중심으로-)

  • Jo, Jang-Hwan;Park, Bo-ram
    • Journal of Digital Convergence
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    • v.17 no.12
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    • pp.445-450
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    • 2019
  • lock in effect This study aims to examine the viewing pattern of travel vlog on video-sharing platform YouTube. Preliminary survey was conducted with in-depth interviews on the usability and sensibility aspects of creating pleasurable interfaces model. As a result, first, viewers obtains general information on travel using travel vlog. Second, there were difficulties from the informational quantity. Third, the contents marketing using travel vlog could have limitation when it comes to the consistency of product's exposure which common mass media advertisement format have. Improvements driven from this study may provide insight in contents marketing strategy to travel-related companies and provide practical help to creators in contents production.