• Journal of Internet Computing and Services
• /
• v.6 no.6
• /
• pp.149-161
• /
• 2005

Catadioptric mirrors are widely used in automatic surveillance system. The major drawback of catadioptric mirror is its unequal image resolution. Equidistance catadioptric mirror can be the solution to this problem. Even double panoramic structure can generate stereo images with single camera system. So two images obtained from double panoramic equidistance catadioptric mirror can be used in finding the depth and height values of object's points. But compared to the single catadioptric mirror. the image size of double panoramic system is relatively small. This leads to the severe accuracy problem in estimation. The exact axial alignment and the exact mount of mirror are the sources that can be avoided but the focal length variation is inevitable. In this paper, the effects of focal length variation on the computation of depth and height of object' point are explained and the effective focal length finding algorithm, using the assumption that the object's viewing angles are almost same in stereo images, is presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.4
• /
• pp.132-152
• /
• 2017

Network performance measure has been more and more important in transportation sector because traffic congestion has been steadily increasing in urban area. VKT is defined a sum of traveled distances of whole vehicles on the road network and one of the most important measure of effectiveness (MOE) for network performance measure. This paper aims to propose a methodology for estimating VKT and to apply it to calculate VKT in 6 major cities in Korea. We calculate VKT in 6 major cities by estimating traffic volumes on the uncollected road sections using regression kriging. It is expected that the proposed methodology can be applied various cities.

• Journal of Korea Water Resources Association
• /
• v.51 no.5
• /
• pp.451-459
• /
• 2018

We calculated the optimal exponent values based on the hourly rainfall data observed in South Korea by treating the exponent value as a variable without fixing it as a square in the inverse distance method. For this purpose, rainfall observation stations providing the data are classified into four groups which are located at the Han river upstream, downstream, the Geum river upstream, and the Nakdong river midstream area. A total of 52 cases were analyzed for seven stations in each group. The optimal exponent value of distance was calculated in a case including one base station and four surrounding stations in a group. We applied the golden section search method to calculating this optimum values using rainfall data for 10 years (2004~2013) and verified the optimum values for the last three years (2014~2016). We compared and analyzed two results of the conventional inverse distance method and the inverse distance method in this study. The optimal values of distance exponent obtained in this study were 3.280, 1.839, 2.181, and 2.005 respectively, in the four groups, and totally mean value was 2.326. It is shown the proposed inverse distance method applying the optimal exponent is superior to the conventional inverse distance method.

• Korean Journal of Plant Resources
• /
• v.19 no.1
• /
• pp.130-132
• /
• 2006

Objective of this study was conducted to determine the proper transplanting distance for turf cultivation in the bare land. For investigating the proper transplanting distance of turf cultivation, it were measured the growth characteristics as plant height, root length, number of branching, number of nodule and length of stolon, and yield properties such as fresh weight and dry matter. In $30{\times}30cm$ of transplanting distance plot, plant height, root length, number of branching, number of nodule and length of stolen were 14.1cm, 22.0cm, 7.0, 31 and 77.5cm, and also the fresh weight and dry matter were 16.1 and 11.0g/plant, respectively. It was observed that growth characteristics and yield properties were highest at $30{\times}30cm$ of transplanting distance, respectively. Therefore, it considered that the proper transplanting distance was $30{\times}30cm$ for turf cultivation in the bare soil.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.1
• /
• pp.78-89
• /
• 1999

In this paper, to improve bandwidth amplitude fluctuation for the broadband signal in indoor propagation environment, we measured and analyzed broadband signal using a vertically polarized, horizontally polarized and circularly polarized antenna, conducting by frequency sweeping method in NLOS (Non-Line-of-Sight) environment. And, to investigate the optimum condition for the improvement of broadband propagation characteristics we also examined the effects of both human motions and transmission antenna height in the NLOS environment. As a result, in the case of NLOS environment, it was found that the amplitude deviation characteristics in frequency bandwidth can be improved by polarization diversity reception. Especially, we found that it is the best effective one to make polarization diversity reception branches, which install the circularly polarized antenna at transmitting end and install the polarized diversity branches received vertical or/and horizontal polarized wave at receiving end. The affection of a human motions is not so much in LOS and NLOS environment, but it can lead to the cause of burst error in indoor digital radio communications as the fade of signal strength become more deeper. And also, when raise the transmitting antenna up to the ceiling, the LOS and NLOS environment could be coexisted. In this case, it can be also inferred that frequency bandwidth amplitude deviation must be fundamentally improved by using polarization diversity reception technique to make the possibility of high transmission rate.

• Journal of the Korean Institute of Gas
• /
• v.25 no.6
• /
• pp.7-13
• /
• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.04a
• /
• pp.1058-1059
• /
• 2017

현실의 물리적인 공간에서의 상호작용으로 얻은 경험을 가상현실에서 완전 몰입형 HMD를 착용한 사용자에게 동일하게 제공하기 위해서는 가상공간 내의 사물의 위치, 높이와 같은 거리감을 효율적으로 제공하는 것은 매우 중요하다. 본 연구에서는 사용자가 느끼는 실재와 가상 간 거리감 보정을 위한 제어 요소 도출을 위해 인체 데이터인 IPD, 키, 눈높이를 측정하여 실험에 반영한다. 실험 시 보다 높은 가상공간 상 거리감 인지를 위해 현실에서의 50cm, 100cm 거리감 인지 훈련을 수행한다. 실험자는 가상공간 상에서 85cm 거리에 위치한 판자를 시각적으로 가늠 후 인지한 만큼 이동하게 되고 그 거리를 측정한다. 측정된 데이터들을 바탕으로 한 분산 분석을 통해 각 데이터 간의 관계를 파악한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.3
• /
• pp.52-61
• /
• 2020

This study developed a legibility distance(LD) model for three colors used in VMS according to luminance under foggy conditions through experiments. For this, a simulated environment was created, and LD values of red, green, and yellow color were collected by increasing the luminance. From the test results, the LDs for red at luminance levels of 2,000 cd/㎡ and 20,000 cd/㎡ and a visibility distance of 10m were 10.2m and 18.8m, respectively, which was an improvement of 84%. The LD was improved by 34% and 17% at a visibility distance of 20 m and 30 m, respectively. For green, the LD was improved by 69%, 63%, and 19% at visibility distance of 10m, 20m, 30m, respectively. For yellow, the LD was improved by 100%, 47%, and 36% at visibility distance of 10m, 20m, 30m, respectively. The LD models for three colors were developed by using two independent variables, luminance value and visibility distance. The adjusted coefficients of the red, green, and yellow model equations were calculated as 0.982, 0.978, and 0.915, respectively, and the explanatory power of all models was very high.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.49 no.2
• /
• pp.130-136
• /
• 2012

In this paper, we propose a near-field range estimation method for a uniform linear array that can calibrate bearing estimation error which give a bad influence on a range estimation process. When a range is fixed, the bearing error is calibrated to maximize the beamformer output by the proposed algorithm based on the gradient method. Simulation results show that the proposed algorithm can compensate the bearing error which is less than the mainlobe beamwidth so that reduce the range estimation error as similar as the case of no bearing error.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.01a
• /
• pp.13-16
• /
• 2022

LSTM과 같은 딥러닝 기법을 이용해 언어모델을 얻는 과정에서 일종의 부산물로 학습 대상인 말뭉치를 구성하는 어휘의 단어벡터를 얻을 수 있다. 단어벡터의 차원을 2차원으로 감소시킨 후 이를 평면에 도시하면 대상 문장/문서의 핵심 어휘 사이의 상대적인 거리와 각도 등을 직관적으로 확인할 수 있다. 본 연구에서는 기형도의 시(詩)을 중심으로 특정 작품을 선정한 후 시를 구성하는 핵심 어휘들의 차원 감소된 단어벡터를 2D 평면에 도시하여, 단어벡터를 얻기 위한 텍스트 전처리 방식에 따라 그 거리/각도가 달라지는 양상을 분석해 보았다. 어휘 사이의 거리에 의해 군집/분류의 결과가 달라질 수 있고, 각도에 의해 유사도/유추 연산의 결과가 달라질 수 있으므로, 평면상에서 핵심 어휘들의 상대적인 거리/각도의 직관적 확인을 통해 군집/분류작업과 유사도 추천/유추 등의 작업 결과의 양상 변화를 확인할 수 있었다. 이상의 결과를 통해, 영화 추천/리뷰나 문학작품과 같이 단어 하나하나의 배치에 따라 그 분위기와 정동이 달라지는 분야의 경우 텍스트 전처리에 따른 거리/각도 변화를 미리 직관적으로 확인한다면 분류/유사도 추천과 같은 작업을 좀 더 정밀하게 수행할 수 있을 것으로 판단된다.