• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1114-1120
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• 2009

The conductivity of various electro-threads is analyzed, and the washable electro-thread embroidery UHF RFID tag antennas using the character shape without T-matching structure are designed by adding a T-matching structure. The RFID tag antenna using the electro-thread is easy to be embedded on a cloth as a wearable antenna because it is flexible and different from general copper inlay shape and tape type tag. The embroidery tag antennas are designed with the English alphabet 'F' and the Korea alphabet 'ㄹ' character. Those are easy to be applied to general clothes. The parameters of antennas are optimized and fabricated. The characteristics and the reading range patterns of the tag antennas are measured. The reading ranges of wet tags(tap water, sea water and soapy water) are tested and compared.

• The Journal of the Acoustical Society of Korea
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• v.18 no.1
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• pp.78-85
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• 1999

In this paper we propose a method to improve the performance of the mel-cepstrum that is widely used in speech recognition. Typically, the met-cepstrum is obtained by critical band filters that have fixed center spacing and bandwidth. However different filter characteristics produce a different mel-cepstrum, resulting in a different performance. In this paper we analyze triangular-shaped and rectangular-shaped filters. By changing the characteristics of filters such as center frequency and bandwidth, we analyze the performance of the met-cepstrum. Then utilizing the simplex method, we propose a method to optimize the critical band filters. Using the dynamic time warping, we performed speaker independent recognition experiments with Korean digit words pronounced by 10 males and 10 females. Experiments show that the rectangular-shaped filters show good performance and the mel-cepstrum obtained by the optimized filters shows better performance than filters that have fixed center spacing and bandwidth.

• Journal of the Korea Convergence Society
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• v.1 no.1
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• pp.69-75
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• 2010

The importance of a using the visual media in English education has been increased. By an importance of Characters in English language content, the more effort is needed for a learner to show the English pronunciation and a realistic implementation. In this paper, we tried to review the Syntax-based Educational Contents Authoring System. For the more realistic lip-sync character, 3D character to enhance the efficiency of the education was constructed. We used a chart of the association structure analysis of mouth's shape. we produced an optimized 3D character through a process of a concept, a modeling, a mapping and an animating design. For more effective educational content for 3D character creation, the next research will be continuously a 3d Character added to a hand motion and body motion in order to show an effective communication example.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.630-639
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• 1998

In this paper, a T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. A slot antenna with T-shaped microstrip feed line is analyzed by using the FDTD method. At first, the propagation process of the reflected wave and the electric field distribution in the time domain is calculated respectively. The antenna parameters also are optimized to get maximum band width, return loss, input impedance, and radiation pattern in the frquency domain by Fourier transforming the time domain results. From the computed results, the optimum slot antenna is designed and fabricated. When the slot width is 16 mm, approximately 35% of bandwidths are obtained without a matching circuit. These computed results using FDTD method were in relatively good accordance with the measured values.

• Journal of Convergence for Information Technology
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• v.10 no.8
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• pp.144-151
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• 2020

User-authentication process is necessary in Fintech Service. Especially, authentication on smartphones are carried out through PIN which is inputted through virtual keypads on touch screen. Attacker can analogize password by watching touched letter and position over the shoulder or using high definition cameras. To prevent password spill, various research of virtual keypad techniques are ongoing. It is hard to design secure keypad which assures safety by fluctuative keypad and enhance convenience at once. Also, to reconfirm user whether password is wrongly pressed, the inputted information is shown on screen. This makes the password easily exposed through high definition cameras or Google Class during recording. This research analyzed QWERTY based secure keypad's merits and demerits. And through these features, creating Tetris shaped keypad and piece them together on Android environment, and showing inputted words as Tetris shape to users through smart-screen is suggested for the ways to prevent password spill by recording.

• Korean Journal of Plant Taxonomy
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• v.34 no.4
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• pp.297-319
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• 2004

Morphological characters of 14 taxa in 6 sections Ischnostachya(one taxon), Anomalae(one taxon), Capitellatae (five taxa), Debiles (one taxon), Capillares (one taxon) and Molliculae (five taxa) of genus Carex (Cyperaceae) were reexamined. The epidermal patterns of perigynium, achene and leaf were investigated using by using a scanning eletron microscope (SEM) and a light microscope (LM). Morphological characters such as rhizome, spike, width of leaf, leaf sheath, involucre, involucre sheath, beak of perigynium, perigynium shape, and leaf epidermal patterns were useful for the identification of observed fourteen taxa. The number of spike, arrangement of psitillate or staminate spike and presence of bract were very useful characters to divide the treated 14 taxa into two groups. A key based on data was presented here.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.161-166
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• 2019

This study examines the flows near the different side mirrors by analyzing the flow due to air resistance at A, B and C models of automotive side mirrors. Model A is a square-shaped side-mirror. Model B is a triangular side-mirror and model C is an oval-shaped side-mirror. The air resistance of the side-mirror while driving is reduced and the automotive power can be reduced by changing the design of automotive side-mirror. As analysis result, as the pressure of air resistance against side mirror becomes larger, it can be seen that the air flow rate becomes great. Therefore, it can be estimated that the smaller the pressure of air resistance, the smaller the flow rate and the better the air flow. Therefore, it can be acknowledged that model B is the best model. As the design data of the automotive side mirror obtained on the basis of this study result are utilized, the esthetic sense can be shown while driving a car at real life.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.379-382
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• 2006

일반적으로 센서 어레이는 많은 채널의 센서를 가지고 있으므로 분석해야 할 데이터의 양이 많다. 따라서 다변량(多變量) 분석 방법을 이용하는데, 크게 통계적 방법과 신경망 방법을 분석하고자 하는 데이터의 특성이나 분석에 필요한 환경 조건에 맞는 분석 방법을 선택하여 이용한다. 센서 어레이의 신호 패턴을 분석하기 위해 본 연구에서는 상태 천이 모델을 이용하여 측정된 가스의 특성을 반영할 수 있는 통계적 방법에 대해 연구하였다. 센서 어레이 신호 데이터를 패턴 모양의 특성을 나타낼 수 있는 상태 천이 모델로 변환하여 가스 종류 식별이 보다 정확하게 이루어 질 수 있도록 모델을 설계하는데 중점을 두고, 모델링 요소인 '상태'는 일정한 시간 간격으로 샘플링 하였을 때의 신호값으로,'천이 관계는 각 천이 벡터의 각으로 각각 정의하여 각도변이 기반 상태천이 모델링을 고안하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.181-190
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• 2014

The underwater acoustic lens system is one of the systems getting high-resolution images on the seafloor by the beam forming method using acoustic lens. The beam forming using acoustic lenses reduces complexity and driving power. When receiving an incoming beam with the acoustic lens array, beam pattern analysis and arrangement problem of the array sensor must be addressed. Introducing SIR (Signal to Interference Ratio), the relationship among sensor interval, beam pattern and image quality would be analyzed. Generally if the sensor interval getting wider, the less effect of the side lobes makes SIR high. If the amplitude of a side lobe is high, SIR is generally getting low. The type of the apodization function changes the width, shape and amplitude of both main lobe and side lobes. Thus an appropriate apodization function can improve SIR. In this paper, SIR is stable at the sensor interval of 13mm with 0-10dB, which is not high relatively. By applying the Chebyshev function, the SIR becomes 80dB over the sensor interval of 37 mm or higher. The Hann and triangular functions demonstrate better SIR when the sensor interval becomes narrower.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.370-374
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• 2003

Cell cracking method using a non-collision was evaluated for the possibility of new red ginseng grinding technique. Based on particle size distribution analysis by 1size shaker, the ratios of 100 mesh penetrated particles were 94.9% for hammer mill (group A) and 95.6% for cell crack (group B). The ratio of 120 mesh penetrated particle of group A was higher than that in group B. The particle size distributions for 100 mesh non-penetrated Powder between 2 groups were not significantly different, and particle size distribution analysis by laser scattering analyzer showed that the particle size ranges were 0.77~128.07 ${\mu}{\textrm}{m}$ for group A and 4.24~180.07 ${\mu}{\textrm}{m}$ for group B. The Particle size distribution in group A was more broad than that in group B. The mean particle size in group B was larger than that in group A, while the standard deviation of particle size distribution in group B was less than that in group A. Structural surface characteristics, in group A, particle size distribution was broad and the distribution curve was amorphous. The structure of individual particles was similar to unequal stone which was roughly grinded and had soft cotton-like surface. In the contrary, in group B, particle size distribution was relatively narrow and also individual size particles were ubiquitously distributed. The structure of individual particles was unequal cut stone shape.