• 한국전자파학회논문지
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• 제30권1호
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• pp.8-11
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• 2019

본 논문에서는 Wolfspeed사(社)의 CGHV1J070D GaN HEMT를 사용하여 Ku-대역에서 동작하는 50 W급 내부 정합 전력증폭기를 설계하고 제작하였다. 전력 트랜지스터를 구성하는 단위 트랜지스터 셀의 출력 신호 간 크기와 위상을 맞추기 위해 슬릿과 비대칭 T-junction을 입출력 정합회로에 사용하였다. 비유전율이 40과 9.8인 두 종류의 박막 기판을 사용하여 제작된 내부 정합 전력증폭기는 펄스 주기 $330{\mu}s$, 듀티 6 %의 펄스 모드 조건에서 전력 성능이 측정되었으며, 16.2~16.8 GHz에서 50~73 W의 포화 출력 전력과 35.4~46.4 %의 드레인 효율, 4.5~6.5 dB의 전력 이득을 보였다.

• 패션비즈니스
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• 제23권4호
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• pp.13-23
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• 2019

This study aims to understand the concept of pixel, the most important factor in constituting a digital image, draw the formative characteristics of pixelation image expressed through non-digital media, and develop fashion design reflecting the characteristics. As a research method, the literature review was conducted in the present study by involving domestic and foreign publications, related academic journals, and theses and dissertations on the pixel and pixelation image based on a qualitative research process. In addition, through an analysis of the cases that borrowed pixelation images in non-digital media like contemporary art and design, etc., an attempt was made to draw the formative characteristics of the pixelation image. Apparently, six fashion design looks are presented in the present study. The formative characteristics of the pixelation image include: first, the repeatability that repeats the minimum unit; second, the incompleteness of the shape appearing through the phenomenon of aliasing due to the characteristics of the pixel; and third, the combination that completes the shape through the combination of individual independent pixels. The results of the expression through reflecting them in fashion design are as follows: first, this study chose one small geometric formative element and presented repeatability by repetitively expressing that element in a textile pattern; second, for incompleteness, this study expressed an incomplete form, handling the edge part of the shape with the method of disentangling the strand; and third, the combination by completing a single look through overlapping of independent textiles and the combination of different independent individuals is expressed.

• 한국정보통신학회논문지
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• 제24권12호
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• pp.1588-1594
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• 2020

본 논문에서는 심층신경망(deep neural network, DNN)을 이용하여 디지털 홀로그램을 생성하는 신경망의 학습을 위한 데이터 균형 조정 방법에 대하여 논의 한다. 심층신경망은 딥러닝(deep learning, DL) 기술에 기반을 두고 있고, 생성형 적대적 네트워크(generative adversarial network, GAN)계열을 이용한다. 심층 신경망을 통하여 생성 하고자하는 홀로그램의 기본 단위인 프린지 패턴은 홀로그램 평면과 객체의 위치에 따라 데이터의 형태가 매우 다르다. 하지만 데이터의 분류 기준이 명확하지 않기 때문에 학습 데이터의 불균형이 생길 수 있다. 학습 데이터의 불균형은 곧 학습의 불안정 요소로 작용한다. 따라서 분류 기준이 명확하지 않은 데이터를 분류하고 균형을 맞추는 방법을 제시한다. 그리고 이를 통하여 학습이 안정화됨을 보인다.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.345-349
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• 1988

The polycrystalline powder of (CaLa) (MgMo)$O_6$ has been prepared at $1350^{\circ}C$ in $H_2/H_2O$ and $N_2$ flowing atmosphere. The powder X-ray diffraction pattern indicates that (CaLa) (MgMo)$O_6$ has a monoclinic perovskite structure with the lattice constants $a_0=b_0=7.901(1){\AA}$, $c =7.875(1){\AA}\;and\;{\gamma}=89^{\circ}$16'(1'), which can be reduced to orthorhombic unit cell, a = 5.551(1) ${\AA}$, b = 5.622(1) ${\AA}$ and c = 7.875(1) ${\AA}$. The infrared spectrum shows two strong absorption bands with their maxima at 590($ν_3$) and 380($ν_4$) cm, which are attributed to $2T_{1u}$ modes indicating the existence of highly charged molybdenum octahedron $MoO_6$ in the crystal lattice. According to the magnetic susceptibility measurement, the compound follows the Curie-Weiss law below room temperature with the effective magnetic moment 1.83(1)$_{{\mu}B}$, which is well consistent with that of spin only value (1.73 $_{\mu}_B$) for $Mo^{5+}$ with $4d^1$-electronic configuration within the limit of experimental error. From the thermogravimetric analysis, it has been confirmed that (CaLa) (MgMo)$O_6$ decomposes gradually into $CaMoO_4,\;MoO_3,\;MgO,\;La_2O_3$ and unidentified phases due to the oxidation of $Mo^{5+}$ to $Mo^{6+}$.

• 정보보호학회논문지
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• 제17권5호
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• pp.39-53
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• 2007

본 연구의 목적은 다양한 이기종 지문입력 센서의 호환을 위한 지문 특징점 보정 알고리즘 개발이다. 본 연구에서는 이기종 지문입력 센서간의 매칭을 위하여 영상 기반의 센서 평가 방법에 따라 Ink-Stamped방법과 인조패턴 방법을 이용하여 평가하였다. 본 연구에서 제안한 보정 알고리즘은 영상 레벨과 템플릿 레벨 모두에서 보정 가능하며, 상대 센서의 사양에 맞도록 보정하는 상대적 해상도 보정 방법과 500, DPI 종횡비(Aspect Ratio)가 1인 사양에 맞도록 보정하는 공통해상도 보정 방법이다. 특히 템플릿 레벨에서의 보정은 특징점이 보정됨에 따라 방향 보정이 변하게 되는데 이를 보정하기 위하여 단위 벡터 방법을 제안한다. 따라서 제안한 보정 알고리즘을 이용한 결과 보정 전 보다 보정 후의 EER 에러가 전체적으로 64.8% 개선됨을 확인 할 수 있었다. 본 연구를 통해 이기종 지문 인식 시스템 통합 시 요구되어지는 비용을 최소화하고 최종 사용자의 편의성을 도모할 수 있으며, 나아가 국가 간 바이오 정보 공유 및 출입국 관리 시스템에 적용하기에도 유용할 것이다.

• 한국기계가공학회지
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• 제20권3호
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• pp.60-67
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• 2021

Recently, research attention has been focused on vibration-free vehicles to transport small numbers of expensive electronic products. Vibration-free vehicles can be used to transport expensive test equipment or semiconductors, mainly produced in the domestic IT industry, and can serve as a readily available transportation system for short driving distances due to the increased efficiency on narrow national highways. This study was aimed at developing a Z-Spring to minimize the vibration by installing an air spring instead of the plate spring applied to conventional freight cars and to prevent the damage of the loaded cargo from the shock occurring during movement. The mechanical properties (elastic modulus, tensile strength, and shear strength) of carbon fiber (CF) and glass fiber (GF) prepreg were derived, and ANSYS ACP PrepPost analyses were performed. It was observed that in the case of hybrid composites, the total deformation and equivalent stress are higher than that of CFRP; however, in terms of the unit cost, the hybrid Z-Spring is more inexpensive and durable compared to the GF.

• Journal of Preventive Medicine and Public Health
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• 제55권1호
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• pp.80-87
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• 2022

Objectives: Dengue remains hyperendemic in Malaysia despite extensive vector control activities. With dynamic changes in land use, urbanisation and population movement, periodic updates on dengue transmission patterns are crucial to ensure the implementation of effective control strategies. We sought to assess shifts in the trends and spatial patterns of dengue in Kelantan, a north-eastern state of Malaysia (5°15'N 102°0'E). Methods: This study incorporated data from the national dengue monitoring system (eDengue system). Confirmed dengue cases registered in Kelantan with disease onset between January 1, 2016 and December 31, 2018 were included in the study. Yearly changes in dengue incidence were mapped by using ArcGIS. Hotspot analysis was performed using Getis-Ord Gi to track changes in the trends of dengue spatial clustering. Results: A total of 10 645 dengue cases were recorded in Kelantan between 2016 and 2018, with an average of 10 dengue cases reported daily (standard deviation, 11.02). Areas with persistently high dengue incidence were seen mainly in the coastal region for the 3-year period. However, the hotspots shifted over time with a gradual dispersion of hotspots to their adjacent districts. Conclusions: A notable shift in the spatial patterns of dengue was observed. We were able to glimpse the shift of dengue from an urban to peri-urban disease with the possible effect of a state-wide population movement that affects dengue transmission.

• Journal of Veterinary Science
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• 제23권5호
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• pp.73.1-73.8
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• 2022

Background: Lumpy skin disease (LSD), a disease transmitted by direct and indirect contact with infected cattle, is caused by the Lumpy skin disease virus (LSDV). The disease affects cattle herds in Africa, Europe, and Asia. The clinical signs of LSD range from mild to the appearance of nodules and lesions in the skin leading to severe symptoms that are sometimes fatal with significant livestock economic losses. Objectives: This study aimed to characterize LSDV strains in the blood of infected cattle in Thailand based on the GPCR gene and determine the phylogenetic relationship of LSDV Thailand isolates with published sequences available in the database. Methods: In total, the blood samples of 120 cattle were collected from different farms in four provinces in the northeastern part of Thailand, and the occurrence of LSDV was examined by PCR based on the P32 antigen gene. The genetic diversity of LSDV based on the GPCR gene was analyzed. Results: Polymerase chain reaction assays based on the P32 antigen gene showed that 4.17% (5/120) were positive for LSDV. All positive blood samples were amplified successfully for the GPCR gene. Phylogenetic analysis showed that LSDV Thailand isolates clustered together with LSDVs from China and Russia. Conclusions: The LSD outbreak in Thailand was confirmed, and a phylogenetic tree was constructed to infer the branching pattern of the GPCR gene from the presence of LSDV in Thailand. This is the first report on the molecular characterization of LSDV in cattle in Thailand.

• The Journal of Advanced Prosthodontics
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• 제13권4호
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• pp.191-204
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• 2021

PURPOSE. The purpose of this study is to present a methodology to evaluate the accuracy of intraoral scanners (IOS) used in vivo. MATERIALS AND METHODS. A specific feature-based gauge was designed, manufactured, and measured in a coordinate measuring machine (CMM), obtaining reference distances and angles. Then, 10 scans were taken by an IOS with the gauge in the patient's mouth and from the obtained stereolithography (STL) files, a total of 40 distances and 150 angles were measured and compared with the gauge's reference values. In order to provide a comparison, there were defined distance and angle groups in accordance with the increasing scanning area: from a short span area to a complete-arch scanning extension. Data was analyzed using software for statistical analysis. RESULTS. Deviations in measured distances showed that accuracy worsened as the scanning area increased: trueness varied from 0.018 ± 0.021 mm in a distance equivalent to the space spanning a four-unit bridge to 0.106 ± 0.08 mm in a space equivalent to a complete arch. Precision ranged from 0.015 ± 0.03 mm to 0.077 ± 0.073 mm in the same two areas. When analyzing angles, deviations did not show such a worsening pattern. In addition, deviations in angle measurement values were low and there were no calculated significant differences among angle groups. CONCLUSION. Currently, there is no standardized procedure to assess the accuracy of IOS in vivo, and the results show that the proposed methodology can contribute to this purpose. The deviations measured in the study show a worsening accuracy when increasing the length of the scanning area.

• The Journal of Korean Physical Therapy
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• 제34권1호
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• pp.45-50
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• 2022

Purpose: The purpose of this study was to compare the spatiotemporal and kinematic gait parameters and muscle activity of the lower extremities between forward walking on sand (FWS) and backward walking on sand (BWS) in normal adults. Methods: This study was conducted on 13 healthy adults. Subjects performed FWS and BWS and the spatiotemporal and kinematic gait parameters of stride time, stride length, velocity, cadence, step length, stance, swing, double support, and hip range of motion (ROM), knee ROM were measured by a wearable inertial measurement unit system. In addition, the muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA) was measured. Results: The stride length, stride velocity, cadence, and step length in the BWS were significantly lower than FWS (p<0.05), and stride time was significantly greater (p<0.05). However, there was no significant difference in the ratio of stance, swing, and double support between the two (p>0.05). The kinematic gait parameters, including hip and knee joint range of motion in BWS, were significantly lower than FWS (p<0.05). The muscle activity of the RF in BWS was significantly higher than FWS (p<0.05), but the muscle activity of the BF, TA, GA did not show any significant differences between the two movements (p>0.05). Conclusion: A strategy to increase stability by changing the gait parameters is used in BWS, and this study confirmed that BWS was a safe and effective movement to increase RF muscle activity without straining the joints. Therefore, BWS can be recommended for effective activation of the RF.