• 한국통신학회논문지
• /
• 제39A권8호
• /
• pp.459-466
• /
• 2014

오랜 시간 보관된 사진 및 인쇄물의 색 바랜 현상은 염료의 특성, 보관 온도, 습도 및 광원 등의 환경적 요인에 따라 다르게 나타난다. 이러한 바랜 영상의 보정을 위해 회색계 알고리즘(gray world algorithm) 또는 WR(white patch retinex)과 같은 전역적 광원 추정을 기반으로 한 방법이 제안되었다. 그러나 색 바랜 현상은 지역적으로 다르게 나타나므로 기존의 전역적 방법으로는 잘 보정되지 않는다. 이에 본 논문에서는 바랜 영상의 지역적 보정을 위해 보정계수 통합 기반 색 보정 알고리즘을 제안하였다. 먼저, 제안한 방법은 다중 크기의 평균 필터를 적용해 지역적인 처리를 수행하고, 회색계 알고리즘을 기반으로 한 영상의 보정계수를 얻는다. 다음으로, R과 B 채널에 적용하기 위해 계산된 다중 크기의 보정계수들을 가중처리하여 합하고, 이 가중처리된 보정계수를 회색계 알고리즘 처리를 통해 결과 영상을 얻는다. 그 결과 제안한 방법은 전역적, 지역적으로 바랜 영상들에 대해 기존의 방법들보다 나은 보정 결과를 보였다.

• 한국인터넷방송통신학회논문지
• /
• 제11권3호
• /
• pp.9-15
• /
• 2011

리플렉트어레이 안테나는 반사경 안테나의 단점을 보완하여 대체할 새로운 형태의 안테나로 대두되고 있다. 하지만 반사판이 단층구조일 경우 대역폭이 매우 좁다는 단점이 있고, 대역폭을 넓히기 위하여 다층구조의 반사판을 사용할 경우 설계가 어렵고 제작 단가가 높아지게 된다. 본 논문에서는 이러한 단점들을 극복하기 위하여 단층구조를 사용하여 제작 단가를 낮추면서 협대역 특성을 극복할 수 있는 정사각형에 U자 모양 슬롯을 낸 패치를 이용하여 리플렉트어레이 안테나를 설계하였다. 제안된 리플렉트어레이 안테나는 12.5 GHz에서 55.5 %의 효율과 14 % 이상의 1 dB gain bandwidth 특성을 갖는다.

• 한국전자통신학회논문지
• /
• 제16권6호
• /
• pp.1075-1080
• /
• 2021

본 논문에서는 단일 측정 사이클 내에서 단일 물체의 범위와 속도를 동시에 측정하기 위한 근거리 차량용 레이더 시스템에 장착되는 24.4GHz 2채널 송신 및 4채널 수신 패치 배열 안테나를 Rogers사의 RO4350B(ε_r=3.48, 0.5T) 기판을 사용하여 설계·제작하였다. 측정을 통해 24.4GHz 주파수에서 안테나 이득( > 10dBi 이상) 및 복사패턴(Elevation HPBW > 10deg.)의 설계 사양을 만족하는 것을 확인하였다.

• 정보통신설비학회논문지
• /
• 제11권2호
• /
• pp.34-38
• /
• 2012

In this paper, the particle swarm optimization (PSO) algorithm is adopted to design a modified ring-slot type patch rectenna with a resonance frequency of 2.45GHz. In order to accomplish minimization of dimensions and circular polarization (CP) and harmonic suppression, axial direction slits and side-cuts are added to the patch of the ring. The PSO manipulated this kind of multi-dimensional problem very well, and as a result, the designed rectenna shows a desirable performance of return loss of 21.36dB and axial ratio of 2.92dB at the frequency of 2.45GHz with compact sizing.

• Journal of electromagnetic engineering and science
• /
• 제18권4호
• /
• pp.261-266
• /
• 2018

This paper reports on the proposed design of a low profile broadband array antenna for home repeater applications. The proposed antenna consists of $1{\times}4$ patch elements and two ground planes, one of which is slitted. By using the gap feeding method, the impedance matching of the antenna is improved by a multi-resonance phenomenon. The proposed antenna provides a wide -10 dB reflection coefficient bandwidth simultaneously covering the Global System for Mobile communications (GSM-1800), Personal Communications Service (PCS), and the Universal Mobile Telecommunication System (UMTS) bands (1.67-2.32 GHz). In order to reduce the mutual coupling between adjacent patch elements, slits are embedded in the ground plane. An isolation level of -20 dB is realized over the entire operating frequency band.

• The Korean Journal of Pain
• /
• 제23권1호
• /
• pp.46-50
• /
• 2010

Spontaneous intracranial hypotension (SIH) is considered to be a very rare disorder. It is characterized by an orthostatic headache that is aggravated with the patient in the upright position and it is relieved by the patient assuming the supine position. SIH is caused by a spontaneous spinal cerebrospinal fluid leakage without the patient having undergone trauma, surgery or dural puncture or having any other significant medical history. An autologous epidural blood patch (EBP) is effective in relieving SIH. We report here on a case of SIH with cerebrospinal fluid leakage at the upper cervical vertebral level and the middle thoracic vertebral level. The points of leakage were identified by radionuclide cisternography, and this patient was successfully managed by injecting an EBP at each level of leakage.

• 디지털산업정보학회논문지
• /
• 제9권2호
• /
• pp.11-15
• /
• 2013

We in order to use WLAN communication device planned wireless USB dongle internal antenna of 2.4 GHz/5.8 GHz band. So it uses square patch dual-wideband and quality is satisfactory and it designed print folded monopole antenna of the shape which is simple. The thickness of the antenna was fed by a $50{\Omega}$ coaxial cable feeding 1mm dielectric constant 4.4 FR4 substrate was used. The overall size of the antenna is $20mm{\times}50mm$. So the internal antenna is suitable. Measurement results of the fabricated antenna, the return loss of more than 10 dB in the two bands could be obtained. Radiation pattern has a maximum gain of 3.75 dBi value.

• 대한기계학회논문집A
• /
• 제29권8호
• /
• pp.1153-1160
• /
• 2005

Many methods of spot weld modeling have been developed to increase efficiency and guarantee the robustness fer the CAE analysis. In this research they are introduced and the performance is compared in a viewpoint of stiffness and durability. For evaluating the performance a multi-spot welded specimen as well as two single welded specimen is used. The results show that the CWELD element considering 'patch to patch' is stiffer than other modeling methods in stiffness and more conservative in durability. It also offers simple modeling and since it is much easier to maintain the orrhogonality of the BAR element expressing a nugget, we can obtain more exact reaction forces and moments in a nugget. Therefore the CWELD element is the most excellent in the assessment of durability.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.1093-1095
• /
• 2003

MSC(Multi-Spectral Camera) system is a remote sensing instrument to obtain high resolution ground image. MSC system includes main control unit, called SBC(Single Board Computer). SBC controls all the sub-units of MSC system and communicates with spacecraft bus. The software developed for SBC should be reliable and autonomous to support various kinds of imaging missions. It is being developed using VxWorks real-time operating system to manage all tasks for all units efficiently. In this paper, the characteristics of the embedded software on the MSC system will be presented. It covers the hardware related characteristics like the BSP(Board Support Package), device driver and code patch mechanism.

• ETRI Journal
• /
• 제41권2호
• /
• pp.262-269
• /
• 2019

This paper introduces a low-cost, high-performance mmWave antenna array module at 77 GHz. Conventional waveguide transitions have been replaced by 3D CPW-microstrip transitions which are much simpler to realize. They are compatible with low-cost substrate fabrication processes, allowing easy integration of ICs in 3D multi-chip modules. An antenna array is designed and implemented using multilayer coupled-fed patch antenna technology. The proposed $16{\times}16$ array antenna has a fractional bandwidth of 8.4% (6.5 GHz) and a 23.6-dBi realized gain at 77 GHz.