• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.5
• /
• pp.69-76
• /
• 2020

The sound signal radiated from an underwater source is received by the hydrophone of the system, including multi-path time-delay and multi-path signal by sea surface and bottom reflection. The system using a time-delay between received signals for the source localization shows performance degradation due to incoherence by the multi-path propagation environment and the disturbance of a marine environment. Various types of array and signal processing have been used for robust source range and bearing estimation in this environment. In this paper, we use a line array composed of doublet array and an estimated time-delay correction method for robust localization performance in a multi-path propagation environment. Three doublet arrays are located on the same line, and the time-delay between signals received on each doublet array is estimated in a two-step procedure. The estimated time-delay value is obtained by the cross-correlation function and corrected by the interaction formula between the center-frequency of received signal and the geometry of the array with respect to aperture. By this proposed procedure, the range and bearing of source from array were calculated. In order to confirm the validity of the proposed method and array, we simulated localization and estimation using the Monte-Carlo method.

• The Journal of the Acoustical Society of Korea
• /
• v.8 no.5
• /
• pp.78-85
• /
• 1989

This paper describes a statistical methods and perception test for extracting the parameters to be used for the synthesis-by-rule of Korean plosives. Formant synthesizer is chosen for the synthesis of the phonemes. Speech materials for the analysis consists of 72 CV monosyllables from the single male speaker. The analysis is done mainly focused on the variation of parameters in time and frequency domain, then perception tests are executed to estimate the effects of variations of the formant transitions.

• Tunnel and Underground Space
• /
• v.21 no.1
• /
• pp.82-92
• /
• 2011

Stereophotogrammetry is used to extract spatial information of an object by constructing a stereo-image from two or more photos. In this study, stereophotogrammetry was adopted for analyzing blast fragmentation of rock blocks in a quarry site. 2D image processing and stereophotogrammetry were applied to the fragmentation analysis of rock blocks horizontally scattered in a laboratory, and their results were compared with physical measurements using a water tank. Fragmentation of rock muckpiles was estimated in laboratory and field tests by using the stereophotogrammetry and statistical analysis.

• Journal of Korea Multimedia Society
• /
• v.11 no.4
• /
• pp.454-461
• /
• 2008

This paper is regarding a new input interface based on displacement of mobile devices having a camera. The mobile device can capture consecutive images by the camera, the displacement of the device is estimated by computing the displacement between consecutive images in real-time. The proposed system extracts feature points based on SUSAN comer detector which has low computational complexity. We generate Voronoi domain by using the two-pass algorithm to match extracted features. Finally, the displacement of a mobile device is estimated by calculating SAD values between two consecutive images. We evaluated the performance of the proposed algorithm with 1500 images. True matching accuracy of the proposed algorithm is 90% and the computation for each image is conducted in 5m sec.

• Journal of Korea Society of Industrial Information Systems
• /
• v.24 no.5
• /
• pp.1-8
• /
• 2019

In this paper, we propose a correcting method of depth pixels which are failed to measure since temporary camera error. A block is modeled to plane and sphere surfaces through measured depth pixels in the block. Depth values in the block are estimated through each modeled surface and a error for the modeled surface is calculated by comparing the original and estimated pixels, then the surface which has the least error is selected. The pixels which are failed to measure are corrected by estimating depth values through selected surface. Simulation results show that the proposed method increases the correction accuracy by an average of 20% compared with the correction method of $5{\times}5$ median method.

• Tunnel and Underground Space
• /
• v.29 no.5
• /
• pp.332-345
• /
• 2019

Maximum dip vector of individual joint plane, which can be uniquely defined on the hemispherical projection plane, has been established by considering its dip and dip direction. A new stereographic projection method for the rock slope analysis which employs the maximum dip vector can intuitively predict the failure modes of rock slope. Since the maximum dip vector is uniquely projected on the maximum dip point of the great circle, the sliding direction of discontinuity plane can be recognized directly. By utilizing the maximum dip vector of discontinuity both the plane sliding and toppling directions of corresponding blocks can be discerned intuitively. Especially, by allocating the area of high dip maximum dip vector which can form the flanks of sliding block the potentiality for the formation of virtual sliding block has been estimated. Also, the potentiality of forming the triangular-sectioned sliding block has been determined by considering the dip angle of joint plane the dip direction of which is nearly opposite to that of the slope face. Safety factors of the different-shaped blocks of triangular section has been estimated and compared to the safety factor of the most hazardous block of rectangular section. For the wedge analysis the direction of crossline of two intersecting joint planes, which has same attribute of the maximum dip vector, is used so that wedge failures zone can be superimposed on the stereographic projection surface in which plane and toppling failure areas are already lineated. In addition the maximum dip vector zone of wedge top face has been delineated to extract the wedge top face-forming joint planes the orientation of which provides the vital information for the analysis of mechanical behavior of wedge block.

• Korean Journal of Heritage: History & Science
• /
• v.37
• /
• pp.151-168
• /
• 2004

The Mireuk Temple Stone pagoda is the largest scale of the existing Stone Pagoda in Korea. A research until now postulates that the Stone pagoda at Mireuk Temple site is composed of nine stories total. However it does not have any records of the detail, dimension, and related methods, etc, even though it is a tectonically large scale building. Only one source of the description is based upon a story which is a sort of Korean myth or traditional story (Samkukyousa, Mu dynasty), although a historical description from a myth or a story is a polemical issue and still needed research in order to prove the truth. One of the ways to make a proof of the truth is an architectural research from the typology of the plane. The types of the plane are differentiated from each era. Therefore, the typology of the plane presents a reason or a proof for the age of the pagoda. Furthermore, the typology of the plane is crucial part in the research of the historical style and it could help the historical style of the Mireuk temple stone pagoda. Research until now shows that the Mireuk temple stone pagoda is the genesis of the stone pagoda shaped after wooden one. It is impossible to find any previous one from the stone pagoda at Mireuk Temple site in Korea. So it is easier to find any previous example from the history of China because Buddhist pagoda-most pagodas are something to do with Buddhism-in Korea is introduced by India via China. This research presents the periodical variation of stone and brick pagoda in both countries. It concludes that the Mireuk temple stone pagoda has $7^{th}$ century's plane type.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.6
• /
• pp.62-71
• /
• 2013

The passive emitter location method using TDOA and FDOA measurements has higher accuracy comparing to the single TDOA or FDOA based method. Moreover, it is able to estimate the velocity vector of a moving platform. Recently, several non-iterative methods were suggested using the nuisance parameter but the common reference sensor is needed for each pair of sensors. They show also relatively low performance in the case of a long range between the sensor groups and the emitter. To solve this, we derive the estimation method of the position and velocity of a moving platform based on the Gauss-Newton method. In addition, to analyze the estimation performance of the position and velocity, respectively, we decompose the CRLB matrix into each subspace. Simulation results show the estimation performance of the derived method and the CEP planes according to the given geometry of the sensors.

• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.193-197
• /
• 2006

지상측정 및 위성영상탑재 광학센서를 이용하여 벼 주요 생육시기에 대한 군락의 엽질소 함량을 추정하였다. 6월부터 10월에 걸쳐 주요 생육시기 $5{\sim}6$회에 걸쳐 Orbview 및 QuickBird와 같이 4m 이하의 고해상도 다중영상을 취득하였다. 위성영상 취득일에 가능한한 맞추어 인공광원을 사용하는 2종의 능동형 광학 (G)NDVI 센서를 이용한 벼 군락의 반사특성을 측정하였으며 동시에 식물체 샘플링을 통한 생육량, 엽면적지수, 엽질소 함량 등을 분석하였다. 시기별 영상의 분광반사특성 및 (G)NDVI와 벼 생육량 및 엽질소 함량과의 관계를 알아보기 위해 상관분석 및 회귀분석을 수행하였다. 지상센서 및 위성영상 유래 (G)NDVI의 값을 서로 비교해 보면 전체적으로 지상센서를 이용하여 측정한 (G)NDVI값이 위성영상 유래 (G)NDVI값보다 크게 나타났다. 하지만 두 센서 모두 엽면적지수 변화에 따른 (G)NDVI의 변화를 살펴보면 엽면적지수가 2 정도가 될 때까지는 함께 증가하다가 2보다 커지면서는 변화가 없이 머무르는 경향은 같게 나타났다. 엽면적지수의 변화는 군락의 엽질소함량 변화와 선형적인 관계($R^2=0.80$)로 나타났다. 분얼기부터 성숙초기까지의 자료를 이용하여 지상센서 및 위성영상 유래 (G)NDVI를 이용한 벼 군락의 엽질소 함량과의 관계를 살펴보니 지수함수적 관계($R^2=0.90$)로 나타났다. 위성영상 유래 (G)NDVI를 이용한 벼 군락의 엽질소 함량 추정식을 이용하여 신평면 최고쌀 생산단지에 대한 엽질소 함량 지도를 작성하였다.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.47 no.4
• /
• pp.25-33
• /
• 2010

In this paper, we propose a simple and efficient algorithm for head pose estimation using a single camera. First, four subimages are obtained from the camera image for face feature extraction. These subimages are used as feature templates. The templates are then tracked by Kalman filtering, and camera projective matrix is computed by the projective mapping between the templates and their coordinate in the 3D coordinate system. And the user's face pose is estimated from the projective mapping between the user's face and image plane. The accuracy and the robustness of our technique is verified on the experimental results of several real video sequences.