• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
• /
• pp.319-324
• /
• 2001

An anatomical head and a multi-layered spherical head with a half-wave handset antenna have been analysed and compared using the Finite-Difference Time-Domain (FDTD) and the Eigenfuntion Expansion Method (EEM), respectively. The analysis shows that results from a simple spherical head with a half-wave antenna can be used to predict the main antenna radiation patters as well as estimates of the peak SAR in a handset user's head. Various representative design data are presented using a six-layered spherical head with a half-wave antenna at 900 MHz

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2017년도 공동학술발표회
• /
• pp.264-264
• /
• 2017

• 한국해안·해양공학회논문집
• /
• 제32권2호
• /
• pp.106-121
• /
• 2020

항 외곽시설 신뢰성 설계가 합리적으로 구현하기 위해서는 우리나라 해양환경 특성이 반영된 확률모형이 필요하며 이러한 시각에서 본 연구에서는 천 해역 확률모형 개발을 위한 기초연구의 일부로 불규칙 파랑 천수 과정을 수치 모의하였다. 수치 모의는 자연해안에서 흔히 관측되는 사주가 원빈에 형성된 해안을 대상으로 수행하였으며 파랑모형은 spatially filtered Navier-Stokes Eq., LES[Large Eddy Simulation], one equation dynamic Smagorinsky turbulence closure 등으로 구성하였다. 불규칙 파랑은 우리나라 동해안에서 관측되는 너울 특성을 반영하기 위해 다양한 첨두 증강계수를 지니는 JONSWAP 스펙트럼과 random phase method를 사용하여 모의하였다. 파고분포의 모수는 먼저 수치 모의에서 관측된 자유수면 시계열 자료를 threshold crossing method로 파별 해석[wave by wave analysis]하여 개별 파랑을 특정하고, 이어 이렇게 특정된 파마루와 파곡 빈도 해석결과로부터 산출하였다. 모의결과 현재 천 해역 파고분포를 대표하는 수정 Glukhovskiy 파고분포는 큰 파고와 작은 파고 발생확률은 과다하게, 중간 크기 파고 발생확률은 과소하게 평가하는 것으로 모의 되었으며, 이에 반해 본 논문에서 제시된 파고분포의 경우 일치도가 상당하였다. 또한, 전술한 수정 Glukhovskiy 파고분포와의 간극은 쇄파역에서 제일 현저하게 관측되어 수정 Glukhovskiy 파고분포를 쇄파역 언저리에 거치되는 외곽시설 신뢰성 설계에 적용하는 일은 지양되어야 할 것으로 판단된다.

• 한국실내디자인학회논문집
• /
• 제25권2호
• /
• pp.59-69
• /
• 2016

This study aimed to understand the importance of applying finishing materials into interior space, and to add meaning to the creation of functional space, associated interior finishing materials with brain science. To achieve this purpose, brainwave(EEG) experiment was conducted. The brainwave appearing when sensing the surface of interior finishing materials with hands was measured. The locations of the electrode were FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, CZ, FZ, and PZ and in addition to these, AFZ was added. Eight(8) kinds of finishing materials: metallic material, film paper, lumbar, stone, glass, silk wallpaper, fabric, and paint were used to measure '${\alpha}$-wave against ${\beta}$ wave.' As a result, it was found that the most activated finishing material in term of relaxation was film paper, followed by metallic, glass, paint, fabric, stone, lumbar, and silk wallpaper. To explain in light of this, (1) '${\alpha}$-wave against ${\beta}$ wave' was the most activated at ch1-FP1 and ch2-FP2, and at ch17-AFZ and ch19-FZ, which indicated that metopic-prefrontal lobe showed the highest activation in relaxation. Film paper, among the finishing materials, showed the highest increase in relaxation. (2) In general, '${\alpha}$-wave against ${\beta}$ wave' relaxation was inhibited at ch13-T3 and ch14-T4, and at ch15-T5 and ch16-T6 and the arousal in the temporal lobe was prominent. Silk wallpaper, among the finishing materials, showed the highest arounsal effect. As a result of measuring the superficial touch on the silk wallpaper, which was regarded as the most rough material among the eight finishing materials, the arousal effect of ${\alpha}$-wave against ${\beta}$-wave, among the brainwave characteristics, was found to be the highest. (3) to judge from the scope of this experiment regarding the tactile sensation over the finishing materials, it is considered that the brainwave reaction sometimes appeared contrastive depending on whether the surface was smooth or rough and there also appeared a difference in relaxation and arousal reaction of the brainwave depending on whether the surface was hot or cold, but the sensation on the surface texture was often evaluated differently depending on who you were. For this reason, this study has some limitations.

• 한국해안·해양공학회논문집
• /
• 제33권5호
• /
• pp.203-216
• /
• 2021

진자형 파력발전장치(Oscillating Wave Surge Converter, OWSC)는 다양한 유형의 파랑 조건에서 효율적으로 작동해야하며 최적의 파랑에너지를 추출하도록 설계되어야 하기 때문에 OWSC의 거동과 관련된 복잡한 파랑-구조물 상호작용이 광범위한 조건에서 검토되어야 한다. OWSC의 개념 설계 및 개발단계에서 수치해석은 OWSC의 설계도구로써 좋은 대안이 될 수 있다. 본 연구에서는 기초적인 OWSC의 거동특성에 대한 검토를 목적으로 오픈소스 CFD를 이용하여 내습하는 파랑에 대한 역삼각형 플랩의 거동특성에 대한 수치해석을 수행하였다. 규칙파 내습시 주기의 변화에 따른 역삼각형 플랩 인근의 자유수면변위 및 회전각도(Flap Rotation angle)를 산정하여 구조물의 거동 특성에 대해 고찰하고, 그 결과를 수리실험과 비교·검토하여 해석성능의 타당성 및 OWSC의 관련 문제를 수치적으로 해석하기 위한 수치모델로서의 적용성능을 검증하였다. 수치해석결과는 파랑과 역삼각형 플랩의 상호작용에 의한 유체역학적 거동 특성을 양호하게 재현함을 확인하였다.

• 한국해안·해양공학회논문집
• /
• 제27권4호
• /
• pp.274-279
• /
• 2015

동해 중부에 위치한 속초항 연안에서 약 11년간 취득한 파랑자료를 스펙트럼법과 파별분석법을 사용하여 분석하고 대표적인 파랑 특성을 검토하였다. 유의파고는 동계에 크고 하계에 작으며, 첨두주기도 동계에 길고 하계에 짧은 특성을 나타내었다. 관측된 최대 유의파고는 8.95 m 였으며 동해선풍에 의하여 발생되었다. 유의파고와 첨두주기 모두 그 분포 형태를 Generalized Gamma 및 Generalized Extreme Value 분포함수보다는 Kernel 분포함수가 보다 잘 재현하였다. 한편, 인근 해역에서의 설계 및 시공에 도움을 줄 수 있도록 파고 자료를 월별 및 파고 구간별로 세분하고 누적출현율을 제시하였다.

• 한국해양공학회지
• /
• 제35권1호
• /
• pp.82-90
• /
• 2021

Owing to the advantages of assuring the best views and seawater exchange, submerged breakwaters have been widely installed along the eastern coast of Korea in recent years. It significantly contributes to promoting the advancement of shorelines by partially inhibiting incident wave energy. Observations were carried out by a pressure-type wave gauge in the Bongpo Beach to evaluate the coefficients of wave transmission via a submerged breakwater, and the results obtained were compared with those of existing conventional equations on the transmission coefficient derived from hydraulic experiments. After reviewing the existing equations, we proposed a transmission coefficient equation in terms of an error function. Although it exhibited robust relationships with the crest height and breaking coefficient, deviations from the observed data were evident and considered to be triggered by the difference in the incident wave climate. Therefore, in this study, we conducted a numerical experiment to verify the influence of wave period on the coefficients of wave transmission, in which we adopted a parabolic-type mild-slope equation model. Consequently, the deviation from calculated results appears to practically cover all deviation range in the observed data. The wave period and direction of the incident wave increased, the transmission coefficient decreased, and the wave direction was determined to demonstrate a relatively significant influence on the transmission coefficient. It was inferred that this numerical study is expected to be used practically in evaluating the design achievement of the submerged breakwater, which is adopted as a countermeasure to coastal beach erosion.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.223-225
• /
• 2008

In this study. we propose a wide bandwidth surface acoustic wave (SAW) motor by design of Inter Digital Transducer (IDT). SAW motor has several benefits compared with preexisted actuator. But it has narrow bandwidth, which causes the lower performance. To widen the bandwidth, the change of IDT structure was proposed, which is slanted IDT and since function apodization. The frequency responses were compared original uniform IDT and changed IDT. And the time responses were compared original uniform IDT and changed IDT. As a result, the feasibility of wide bandwidth SAW motor was certified.

• 한국정보통신학회논문지
• /
• 제16권6호
• /
• pp.1141-1147
• /
• 2012

본 논문에서는 Debye 분산 특성을 가지는 복제 방지용 PUF를 설계하기 위한 전자계 해석 방안을 고려하였다. 공기층과 유전체 기판 위에 형성된 분산매질(Si)로 구성된 1차원 모델 내에 전파하는 펄스를 모형하기 위해 FDTD법을 이용하였다. 불연속 경계면에 도달한 펄스는 일부 반사되고 일부는 투과되어 빠르게 감쇠되는 것으로 나타났다. 그 결과 FDTD법에 의한 유전체 기판을 고려한 Debye 분산특성을 가지는 1차원 복제방지용 PUF 모델링에 적용 가능한 것을 확인하였다.

• 해양환경안전학회지
• /
• 제1권1호
• /
• pp.95-106
• /
• 1995

The small-waterplane-area-twin-hull(SWATH) ship has been recognized as a promising high performance ship because of her superior seakeeping characteristics and large deck area for various operations compared to the conventional monohull ship. significant advances in analytical technics for the prediction of the ship motions, wave loads and structural responses, structural fatigue and its prediction, and hull vibration for ship motions, wave loads and structural responses, structural fatigue and its prediction, and hull vibration for SWATH ship have been much developed during the last twenty years. Based on these developments in technology an integrated computational procedures for prediction wave loads and structural responses can be used to get a accurate results. But the major problem of SWATH ship's structural design is the accurate prediction of structural responses by the maximum critical loads likely to be experienced during the life of SWATH. To get a easier and safer computational procedures and the analytical approach for determining the accurate structural responses, a case study has been presented through the project experienced.