• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1669-1670
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• 2006

LED have many problem as narrow light view angle, high price, drift phenomenon of color coordinate, high heating problem for lower power, lower weight and small size. But, with the development of blue LEDs and the improvement of LED brightness, color variation are becoming more and more popular as lighting and application devices in this page, 1 used the Light Tools which was a simulation program in order to recognize optical a few characteristic of LEDs arrangement along reflector matrial and designed LED Arranged 5 phi LED in 5mm interval In the square that was $10{\times}10$ And designs a reflection board on pcb, structural design of PCB changed as five type. - Aluminum, Gold. Chromium, Nickel, Copper.

• 전자공학회논문지A
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• 제30A권10호
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• pp.33-40
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• 1993

A reflection type 16x8 S-SEED array from LP(Low Pressure)-MODVD-grown GaAs/AlGaAs extremely shallow quantum well(ESQW) structures, with 4% Al fraction, has been fabricated. Its intrinsic region consists of 50 pairs of alternating 100.angs. GaAs and 100.angs. $Al_{0.04}$Ga$_{0.96}$As layers. A multilayer reflector stack of $Al_{0.04}$/Ga$_{0.96}$ As(599$\AA$)/AlAs(723$\AA$) was incorporated for the reflection plane below the p-i-n structures. The device processing after the MOCVD growth includes the mesa etching, isolation etching, insulator deposition, p & n metallization, and AR(Anti-Reflection) coating. For switching characteristics of the S-SEED in the form of p-i-n ESQW diode, the maximum optical negative resistance was observed at 856nm. Reflectance measurements showed a change from 15.6% to 43.3% for +0.9V to -6V bias. The maximum contrast ration of the S-SEED array was 2.0 and all the 128 devices showed optical bistability with contrast ratios over 2.4 at 5V reverse bias.

• 한국전자파학회논문지
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• 제21권10호
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• pp.1177-1183
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• 2010

본 논문에서는 스피드론 프랙탈(Spidron fractal)을 이용하여 원형 편파를 발생시키는 마이크로스트립 슬롯 안테나를 설계하였다. 설계된 안테나의 접지면에는 직각삼각형 7개가 연속적으로 붙어있는 형태의 슬롯이 형성되어 있다. 이 슬롯은 원형 편파 발생을 위한 구조이고, 설계된 안테나는 단일 급전 구조로 원형 편파를 발생시킨다. 설계된 안테나의 이득을 높이기 위해, 마이크로스트립 급전 라인의 아랫 부분에 반사판을 배치하였다. 시뮬레이션을 이용하여 첫 번째 삼각형의 높이, 빗변과 높이 사이의 각도, 마이크로스트립 급전 라인의 위치, 기판과 반사판 사이의 간격 등을 조절하였고, 최적화 설계하였다. 제안된 안테나는 Taconic사의 RF-35 기판을 사용하여 제작하였다. 제작된 안테나의 크기는 $40{\times}40{\times}18.6mm^3$이고, 반사판은 접지면으로부터 18.6 mm 아래에 위치한다. 측정된 안테나의 이득은 4.3 GHz에서 6.7 dBi이고, -10 dB 반사계수 대역폭은 41 %, 3 dB 축비 대역폭은 7.4%이다.

• 한국통신학회논문지
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• 제21권6호
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• pp.1587-1595
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• 1996

We obtained the predicted and measured results for the reflection coefficient and radiation pattern of Ka-band (20- GHz) corrugated horn, which is usually used for feeder of reflector antenna for satellite communication, using suface impedance condition. In order to predict the reture losses of corrugated horn, we analyzed propagation constant of hybrid mode in the corrugated waveguide and then obtained the total reflection coefficient using the circuti theory of multi-step transformer. We also got the radiation pattern of corrugated horn with small flare angle, considering the phase deviation and integrate transverse field on aperture. A test model of corrugated horn antenna for Ka-band designed using theory and program displayed performance and the results agree with the theoretical prediction.

• 통합자연과학논문집
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• 제2권2호
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• pp.82-85
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• 2009

Distributed Bragg reflector (DBR) porous silicon (PSi) was generated by an electrochemical etching a bragg structure into a silicon wafer through electrode current in aqueous ethanolic HF solution. DBR PSi exhibiting unique reflectivity was successfully obtained by an electrochemical etching of silicon wafer using square current waveform. The multilayered photonic crystals of DBR PSi exhibited the reflection of a specific wavelength with high reflectivity in the optical reflectivity spectrum. In this work, we have developed a method to create refractive index in Si substrate through intensity of an electric current. The electrochemical process allows for precise control of the structural properties of DBR PSi such as thickness of the porous layer, porosity, and average pore diameter. The number of reflection peak of DBR PSi and its pore size increased as the intensity of electric current increased. This might be a demonstration for the fabrication of specific reflectors or filters.

• 통합자연과학논문집
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• 제5권1호
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• pp.27-31
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• 2012

Relationship between reflection resonance and applied current density in Bragg photonic crystal has been investigated. Multiple bit encodes of distributed Bragg reflector features have been prepared by electrochemical etching of crystalline silicon by using various square wave current densities. Optical characterization of multi-encoding of distributed Bragg reflectors on porous silicon was achieved by Ocean optics 2000 spectrometer for the search of possible applications of multiple bit encoding of distributed Bragg reflectors such as multiplexed assays and chemical sensors. The morphology and cross-sectional structure of multi-encoded distributed Bragg reflectors was investigated by field emission scanning electron micrograph.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.81-85
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• 2013

A miniaturized fluorescence detection system based on total internal reflection (TIR) configuration, which is applicable to detecting the presence of biological materials labeled with fluorescence dye in micro total analysis systems (${\mu}TAS$), is proposed. In conventional fluorescence testing and analysis devices, interference between the excitation light beam and the emitted light from dyes is unavoidable. This paper presents a fluorescence detection system based on TIR configuration that allows the excitation light beam and the emitted light to be spatially perpendicular to each other so as to minimize the interference where fluorescence emission is detected at the orthogonal angle to the excitation beam. We achieved the limit of detection of about 5 nmol/L with a high linearity of 0.994 over a wide range of 6-FAM mol concentration, being comparable to that in earlier studies.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.192-197
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• 2023

A Distributed reflection denial of service (DRDoS) is a variant of DDoS attacks that threatens the availability of services to legitimate users. In response to this evolving threat landscape, the cybersecurity industry and service providers have intensified their efforts to develop effective countermeasures. Despite these efforts, attackers continue to innovate, developing new strategies and tools while becoming more sophisticated. Consequently, DRDoS attacks continue to be harmful. Therefore, ongoing research and development is essential to improve defense against DRDoS attacks. To advance our understanding and analysis of DRDoS attacks, this study examines the unique characteristics of DRDoS attacks and quantifies the risks involved. Additionally, it adopts a quantitative rather than traditional qualitative methods to derive and apply risk, particularly the probability of loss that can be caused by DRDoS attacks.

• 한국음향학회지
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• 제23권4호
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• pp.268-273
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• 2004

본 연구에서는 원호의 내부벽면에 1열로 배열된 어레이 트랜스듀서를 이용한 반사-투과형 생체진단용 역산란 초음파 단층화상법을 제안하였다. 제안된 방법에서는 대상 물체의 배면에 반사판을 배치하여 경면효과를 이용하였고, 유한 대역을 갖는 펄스파를 송신파로 사용하여 다중 주파수 성분을 이용함으로써 데이터 관측 범위를 줄일 수 있었다. 제안된 방법의 성능 평가를 위하여 컴퓨터 시뮬레이션을 이용한 모의 생체 조직에 대한 유효성을 검토한 격과, 트랜스듀서군의 송수신 각도 범위가 30도로 극히 좁은 범위로 제한되었음에도 불구하고 정량적인 화상재현이 가능함을 확인할 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.208-212
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• 2008

Gas hydrate has been paid attention to study for because: 1) it can be considered as a new energy resources; 2) one of reasons causing the instability of sea floor slope and 3) a factor to the climate change. Bottom simulating reflector (BSR) defined as seismic boundary between the gas hydrate and free gas zone has been considered as the most common evidence in the seismic reflection data for the gas hydrate exploration. BSR has several characteristics such as parallel to the sea bottom, high amplitude, reducing interval velocity between above and below BSR and reversing phase to the sea bottom. Moreover, instantaneous attribute properties such as amplitude envelop, instantaneous frequency, phase and first derivative of amplitude of seismic data from the complex analysis could be used to analyze properties of BSR those would be added to the certain properties of BSR in order to effectively find out the existence of BSR of the gas hydrate stability zone. The output of conventional seismic data processing for gas hydrate data set in Ulleung basin in the East sea of Korea will be used for complex analyses to indicate better BSR in the seismic reflection data. This result of this analysis implies that the BSR of the analyzed seismic profile is clearly located at the two ways time (TWT) of around 3.1 seconds.