• 한국측량학회:학술대회논문집
• /
• 한국측량학회 2006년도 춘계학술발표회 논문집
• /
• pp.287-291
• /
• 2006

Currently application of high-resolution satellite imagery is expanding with development of high tech optical and space aviation technology. Although using 3 dimensional modeling technology in order to attain accurate terrain information using existing ground control points is the most dependable reference data, such means are unapplicable for certain area because of it's limited access. In this study, we have researched into ways to utilizing high resolution satellite images from IKONOS and Quickbird, and sub-meter class satellites images that will be utilized In the future such as Arirang images and PLEIADES images for unaccessible areas. For that purpose we have created accuracy verification and GCP files for existing ortho-imagery and digital elevation model. The results showed that accuracy of ortho-Imagery and digital elevation model was RMSE X:3.043m, Y:2.921m, Z:6.139m. Also, after ortho-rectifying IKONOS images using ground control points extracted from ortho imagery and digital elevation model the accuracy of the imagery was RMSE X:3.243m, Y:2.067m, Z:1.872m.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1992년도 학술논문발표회 논문집 제11권 1호
• /
• pp.23-28
• /
• 1992

The purpose of this paper is to develop a new adaptive echo canceller improving convergence speed and near-end-talker detection performance of the conventional echo canceller. In a conventional adaptive echo canceller, an adaptive digital filter with TDL(Tapped-Delay Line) structure modelling the echo path uses the LMS(Least Mean Square) algorithm to cote the coefficients, and NET detector using energy comparison method prevents the adaptive digital filter to update the coefficients during the periods of the NET signal presence. The convergence speed of the LMS algorithm depends on the eigenvalue spread ratio of the reference signal and NET detector using the energy comparison method yields poor detection performance if the magnitude of the NET signal is small. This paper presents a new adaptive echo canceller which uses the pre-whitening filter to improve the convergence speed of the LMS algorithm. The pre-whitening filter is realized by using a low-order lattice predictor. Also, a new NET signal detection algorithm is presented, where the start point of the NET signal is detected by computing the cross-correlation coefficient between the primary input and the ADF(Adaptive Digital Filter) output while the end point is detected by using the energy comparison method. The simulation results show that the convergence speed of the proposed adaptive echo canceller is faster than that of the conventional echo canceller and the cross-correlation coefficient yield more accurate detection of the start point of the NET signal.

• 한국문헌정보학회지
• /
• 제38권3호
• /
• pp.103-118
• /
• 2004

인터넷 서비스가 안정화 위주로 옮겨가면서 웹서비스의 품질 향상을 위해 보다 많은 투자가 이루어지고 있다. 대규모의 다양한 정보를 제공하고있는 전자도서관 웹 사이트가 객관적인 평가 시스템을 개발하여 적용하므로써 이용자들에게 서비스의 만족도를 높일 수 있는 기준을 마련할 필요가 있다. 본 연구에서는 검색성, 개인화로 기준을 도출하였다. 구축된 사용성 평가 모델을 계층적 분석방법(Analytic Hierarchy Process AHP)을 이용하여 평가하고 검증하였다. 평가지침으로 설정된 항목을 설문조사를 하여 계층적 분석방법에 기초한 디지털 도서관 웹 사이트 평가 모델을 개발하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
• /
• pp.37-39
• /
• 2009

In the research of speech recognition, locating the beginning and end of a speech utterance in a background of noise is of great importance. Since the background noise presenting to record will introduce disturbance while we just want to get the stationary parameters to represent the corresponding speech section, in particular, a major source of error in automatic recognition system of isolated words is the inaccurate detection of beginning and ending boundaries of test and reference templates, thus we must find potent method to remove the unnecessary regions of a speech signal. The conventional methods for speech endpoint detection are based on two simple time-domain measurements - short-time energy, and short-time zero-crossing rate, which couldn't guarantee the precise results if in the low signal-to-noise ratio environments. This paper proposes a novel approach that finds the Lyapunov exponent of time-domain waveform. This proposed method has no use for obtaining the frequency-domain parameters for endpoint detection process, e.g. Mel-Scale Features, which have been introduced in other paper. Comparing with the conventional methods based on short-time energy and short-time zero-crossing rate, the novel approach based on time-domain Lyapunov Exponents(LEs) is low complexity and suitable for Digital Isolated Word Recognition System.

• 대한기계학회논문집A
• /
• 제29권3호
• /
• pp.418-424
• /
• 2005

We present the design, fabrication and experimental results of 4-bit digital microinjectors, whose ejected droplet volumes are adjusted by the digital operation of a 4-bit microheater array. We design the reference microinjectors as well as its comparative test structures. In the fabrication process, we use a five-mask micromachining process and the total chip size of the fabricated microinjector is $7,640{\mu}m{\times}5,260{\mu}m.$ We measure the ejected droplet volumes and velocities, which are adjusted from $12.1{\pm}1.0~55.6{\pm}14.7pl\;and\;2.3{\pm}0.1~15.7{\pm}0.8m/s.$ respectively, depending on the 15 possible combinations of 4-bit microheater array. We also experimentally characterize the effect of geometric variation including the microheater size, inter-microheater gap, microchannel width and sequential operation of microheater array on the ejected droplet volume and velocity. Among these parameters, we find that the microheater size is the most dominant parameter affected to the ejected droplet volumes and velocities. Thus, the present microinjector has a potential for application to the high-resolution inkjet printers with multiple gray levels or high-precision fluid injectors with variable volume control.

• 한국컴퓨터정보학회논문지
• /
• 제8권4호
• /
• pp.87-91
• /
• 2003

본 논문에서는 현재 주차장에서 사용되는 입출 차량의 관리를 정기권 카드나 티켓발행기와 병행하여 사용될 수 있는 자동차 번호 인식 시스템을 개발하였다. 주차장은 차량의 흐름을 원활하고 신속하게 처리해야 하기 때문에 많은 자동차 번호 인식시스템을 도입했으나 운영 면에서 여러 가지 문제점을 가지고 있었다. 본 논문에서는 이러한 단점을 보완하기 위하여 기존의 시스템을 바탕으로 유동적인 시스템을 개발하였다. 자동차 번호 인식시스템은 주차장에 설치될 경우 99%의 성능을 가져야 하지만 날씨의 변화와 계절이 변동함에 따라 많은 영향을 받고 있다. 따라서 본 논문에서는 4계절과 날씨에 민감함을 고려하여 차량번호판 영역을 히스토그램 모폴로지를 사용하여 번호판 영역을 추출하고 신경망을 사용하여 숫자만을 인식하는 시스템을 개발하였다.

• Journal of Preventive Medicine and Public Health
• /
• 제20권2호
• /
• pp.255-260
• /
• 1987

The digital dust indicator (Sibata P-5), one of the direct·reading instruments was evaluated for the respirable dust in the underground coal mine environments. As a reference, respirable dust was determined using three cyclones and/or impactors. All the tests were performed on aerosol in twenty underground coal mines. The coefficients of mass-relative concentration were $0.067{\pm}0.054$ (Mean$\pm$Standard deviation) (range: 0.006-0.172). The relationship between relative concentration and temperature was not significant statistically. Also, the relationship of relative concentration and relative humidity was not significant. Mass concentration and relative concentration were $5.31{\pm}5.22mg/m^3$ and $162{\pm}163$ CPM ($Mean{\pm}Standard$ deviation) respectively. The range of mass concentration was $1.22-22.69mg/m^3$; relative concentration 16-628 CPM. The relationship of mass concentration and relative concentration was not significant in these ranges.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1997년도 추계학술대회
• /
• pp.206-209
• /
• 1997

The stereostatic surgery becomes a important part of neurosurgery. The conventional style of stereostatic system uses a input method of film digitizing. It is time consuming and laborious. In this paper, we presented a system that can manage digital images from medical imaging machine to surgery assisting program. CT images were transferred in DICOM format to a surgery assisting computer in a operation room through PACS. The streotatic surgery assisting program processed the digital images and calculated the parameters that were required in steostatic surgery. The assisting program were developed that can detect the reference points automatically, transform CT coordinate to frame coordinate and calculate the RM (Riechert-Mundinger) frame. This system were applied to clinical cases in Seoul National Univ. Hospital. The two advantages of this system were revealed. The processing time from imaging to surgery parameters were much aster than conventional system. The surgery accuracy were more mininute as the digitizing error were reduced. This system were a good application of connecting imaging machines to clinical treatment system through PACS.

• 한국측량학회지
• /
• 제25권6_1호
• /
• pp.517-528
• /
• 2007

Extraction of the coastal boundary is important because the boundary serves as a reference in the demarcation of maritime zones such as territorial sea, contiguous zone, and exclusive economic zone. Accurate nautical charts also depend on well established, accurate, consistent, and current coastline delineation. However, to identify the precise location of the coastal boundary is a difficult task due to tidal and wave motions. This paper presents an efficient way to extract coastlines by applying digital image processing techniques to Synthetic Aperture Radar (SAR) imagery. Over the past few years, satellite-based SAR and high resolution airborne SAR images have become available, and SAR has been evaluated as a new mapping technology. Using remotely sensed data gives benefits in several aspects, especially SAR is largely unaffected by weather constraints, is operational at night time over a large area, and provides high contrast between water and land areas. Various image processing techniques including region growing, texture-based image segmentation, local entropy method, and refinement with image pyramid were implemented to extract the coastline in this study. Finally, the results were compared with existing coastline data derived from aerial photographs.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2012년도 추계학술대회
• /
• pp.163-166
• /
• 2012

본 논문에서는 차세대 비디오 표준인 High Efficiency Video Coding(HEVC)의 영상 부호화 과정의 시간복잡도 감소를 위한 효율적인 Prediction Unit(PU)레벨 움직임예측(Motion Estimation, ME) 병렬화의 구현 기법을 제시하고자 한다. 움직임예측 과정은 부호화기에서 80%의 복잡도를 차지하는 과정으로 고속 부호화의 걸림돌이 되고 있다. 이를 해결하기 위한 방법으로 제안된 것이 움직임예측 알고리즘의 병렬화이다. 알고리즘 수준에서 ME 의 일부인 Merge Estimation 의 병렬화를 위해서 Merge Estimation Region (MER)기반의 ME 방법이 제안되었다. 하지만 HEVC Test Model reference software(HM)에 반영된 MER 을 이용하여 실제로 병렬화된 ME 를 구현하는 과정에서는 알고리즘 측면에서 아직 고려되지 않은 문제들이 존재한다. 이에 본 논문에서는 MER 을 사용한 안정적인 병렬 ME 를 구현하기 위한 전략으로 각 PU 의 정보를 독립적으로 사용하기 위한 부분 순차화 방법과 메모리 접근제한을 이용한 병렬화 방법을 제시한다. 실험을 통해 본 연구의 우수성이 확인되었는데, 제안된 방법에 기반을 둔 구현에서 순차적인 ME 를 이용한 부호화기 대비 평균 25.64%의 전체 부호화 과정 시간의 감소가 나타났다.