• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.89-98
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• 2004

In this paper, we implement a digital holographic security card system that combines digital holographic memory using random phase encoded reference beams with electrical biometrics. Digitally encoded data including a document, a picture of face, and a fingerprint are recorded by multiplexing of holographic memory. A random phase mask encoding reference beams are used as a decoded key to protect illegal counterfeit. As a result, we can achieve a raw BER of 3.6${\times}$10-4 and shift selectivity of 4${\mu}{\textrm}{m}$ using the 2D random phase mask. Also, we develop a recording pattern and image processing which are suitable for a low cost reader without a position sensing photo-detector for real time data extraction and remove danger of fraud from unauthorized person by comparing the reconstructed holographic data with the live fingerprint data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.567-577
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• 1998

When continuous and discontinuous microstrip is analyzed with FDTD(Finite Difference Time Domain) method, we used Berenger's 3D-PML as absorbing boundary condition, and IST(Inner Source Technique) was used for source excitation instead of front excitation that is existing method. In the case using IST, we have observed that analyzed characteristic is not affected by the reduced computational domain of the side and top face in which evanescent field and radiation field is exist. Also, if we control the position of the inner source, we could effectively reject the influence of the reflective wave by mean of imperfective boundary condition. In this paper, by using IST, we have calculated dispersive characteristic and characteristic impedance of the microstrip. And we have calculated magnitude and phase of the scattering coefficient, and obtained equivalent circuit of the open microstrip end.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.44-56
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• 2008

Previous hardware devices to capture human motion have many limitations; expensive equipment, complexity of manipulation or constraints of human motion. In order to overcome these problems, real-time motion capture algorithms based on computer vision have been actively proposed. This paper presents an efficient analysis method of multiple view images for real-time motion capture. First, we detect the skin color regions of human being, and then correct the image coordinates of the regions by using camera calibration and epipolar geometry. Finally, we track the human body part and capture human motion using kalman filter. Experimental results show that the proposed algorithm can estimate a precise position of the human body.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.821-830
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• 2010

Deck plates and hatch coming of large container carrier and offshore structures are joined by ultra-thick plates whose thickness is more than 60mm. Traditionally FCAW has been used to join the thick plates in butt joint. However, FCAW has been replaced with EGW since the welding efficiency of EGW is higher than that of FCAW. Tandem EGW using two electrodes has been applied to vertical position welding by several shipyards. EGW requires one or two layers of bead whereas FCAW requires more than 20 layers of weld bead in thick welding. However, high welding residual stresses are generated by EGW since it uses higher heat input than FCAW. In the present study, a finite element model is suggested to predict the residual stresses induced by the tandem EGW. Butt specimen of EH40 TMCP shipbuilding steel plates vertical welding was modeled by a three-dimensional model. Residual stresses were measured by X-ray diffraction method and to verify the numerical result. The results show a good agreement with experimental result.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.219-228
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• 2012

In this paper, we propose a paper keyboard piano implementation using the finger movement detection with the 3D image data from a kinect. Keyboard pattern and keyboard depth information are extracted from the color image and depth image to detect the touch event on the paper keyboard and to identify the touched key. Hand region detection error is unavoidable when using the simple comparison method between input depth image and background depth image, and this error is critical in key touch detection. Skin color is used to minimize the error. And finger tips are detected using contour detection with area limit and convex hull. Finally decision of key touch is carried out with the keyboard pattern information at the finger tip position. The experimental results showed that the proposed method can detect key touch with high accuracy. Paper keyboard piano can be utilized for the easy and convenient interface for the beginner to learn playing piano with the PC-based learning software.

• Korean Journal of Applied Biomechanics
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• v.26 no.4
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• pp.333-341
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• 2016

Objective: The purpose of this study was to assess the consistency of the gliding and push-off motion for single leg skating from the first to fourteenth steps. We hypothesized that: 1) there would be no difference in stroke trajectory, step rate, and cycle rate between the left and right steps of gliding; and 2) there would be a difference in the resultant velocity of toe push-off and the horizontal velocity of the center of mass after six step push-offs. Method: The study included five male 500-m speed skaters (mean height, $1.80{\pm}0.02m$; mean weight, $76.8{\pm}3.96kg$; record, $35.83{\pm}0.30sec$; 100-m record, <9.97 sec). Data were collected from the first to fourteenth steps (40 m) and recorded using five digital JVC GR-HD1KR video cameras (Victor Co., Japan) operating at a sampling frequency of 60 fields/sec and shutter speed of 1/500 sec. For each film frame, the joint positions were digitized using the KWON3D motion analyzer. Position data were filtered with low-pass Butterworth $4^{th}$ order at the cut-off frequency of 7.4 Hz. Results: The right toe of the skating trajectories at $2^{nd}$, $5^{th}$, and $7^{th}$ strokes differed from those of the left toe. The angles of the right and left knee demonstrated unbalanced patterns from the flexion and extension legs. The step and cycle rates of the right and left leg differed from the start until 20 m. The resultant velocities of the toe at the push-off phase and of the body mass center diverged before the six push-offs. Conclusion: This study's findings indicate that the toe of skating trajectory on left and right sliding after push-off should maintain a symmetrical trajectory. The resultant velocity of toe push-off and horizontal velocity from the center of body need to be separated after about six step push-offs.

• Mycobiology
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• v.36 no.3
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• pp.143-147
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• 2008

We have detected the slime mold, Diachea leucopodia (GNU06-10) in a strawberry greenhouse located in Sancheong-gun, Gyeongnam. Typical fruiting bodies had developed gregariously on the strawberry leaves, petioles, and plant debris on ground soil habitat, and also surprisingly on plastic pipes and a vinyl covering. Field samples were examined via stereomicroscopy, light microscopy, and SEM for the determination of morphological characteristics. Dark-brown to black spores formed gregariously within the stipitate cylindrical sporangium, and were covered by an iridescent peridium, which may be intact at maturity, or may have disintegrated. The upper portion of the peridium generally breaks up to expose the spores, whereas the lower portion was usually persistent. The results of energy dispersive X-ray spectrometer (EDS) analysis showed that lime was present in the stalk and columella but absent from the spores, capillitium, and peridium. The above characteristics confirm its taxonomic position in the genus Diachea. However, this genus is intermediate in character between the Physarales and Stemonitales of the Myxogastromycetidae. Hence, this genus had been classified as a member of the Stemonitales until the mid-1970's, on the basis of its iridescent peridium and noncalcareous capillitial system, similar to Comatricha of the Stemonitaceae. By way of contrast, emphasis on morphological characteristics, most notably the calcareous stalk and typical columella, places Diachea within the order Physarales. The presence of a phaneroplasmodium during the trophic stage and lime deposition in its sporophores, as was confirmed in this work, supported the inclusion of Diachea in the Physarales, and the noncalcareous capillitial system verified its identification as a member of the Didymiaceae. Further characteristics of the species D. leucopodia include the following: phaneroplasmodium, spore globose 7.5 ${\mu}m$ in diameter, very minutely roughened; sporangia $500{\mu}m\times1mm$, more or less cylindrical, gregarious, stalked 1.2mm; stalk and columella white.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.48-58
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• 2009

In recent years, construction worker safety in construction site is important. Especially, the frequent collapse accidents have happened in tunnels, utility tunnel and underground structure, so that the importance of worker safety is greatly emphasized. It is difficult to communicate with other workers in underground space, using the current cable or wireless communicator. When the accident is occurred, it can't rescue workers. This is the reason that it has a deficiency to find a location of survivor and communicate rescure crew and field workers. In this paper we extract the optimal technical factors of USFSS(Underground Structure Field Support System) based on integrated technique of wireless communication and location awareness. And USFSS developed in this study is suited for bad environment of underground structure construction and able to track 3D position of laborer and communicate mutually.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.29-49
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• 2021

This paper proposes the Hunminjungum Keypad that applied the creation principle of Hunminjungum to the design of keypad. The proposed keypad arranged 28 letters of Hunminjungum to have correlations with each other between consonants, between vowels, and between consonants and vowels. That is, Consonant buttons are arranged by grouping letters of the same sound by sounds of five voices. And the vowel buttons are arranged at the bottom and the right side of the consonant area according to the position where a vowel is attached to the consonant. In the meantime, Hangul keypads have mainly used 12 button keypads in 4 lines and 3 columns. These keypads have structurally disadvantageous in the touch count and moving distance. Recently, keypads with many letter buttons such as QWERTY and single-vowel are also used a lot. If the number of letter buttons provided in the keypad increases, touch count decreases. And If the letter buttons are arranged to have a correlation with each other, the moving distance becomes smaller. The experimental results show that the proposed keypad has high efficiency in all evaluation factors such as touch count, moving distance and input time.

• Journal of the Korea Society of Computer and Information
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• v.26 no.5
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• pp.9-16
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• 2021

In this paper, we propose a building exploration drone that can be used for a digital twin-based building control system. The existing building control system using a fixed position sensor box has a problem that a management blind spot occurs. And because people patrol themselves, it takes a lot of human resources. In this paper, a drone equipped with a temperature and humidity sensor and a gas leak detection sensor is used to search the internal path of the building centering on the control blind spot. It also aims to solve the problem of the building control system by transmitting information in real time along with the video. In addition, it has a stable hovering function using an optical floor sensor and can be applied to an existing digital twin-based building control system. The results of this study are believed to be of great help in improving the quality of digital twin control systems using drones.