Recently, GIS(Geographic Information System) is used to extract various hydrological factors from DEM(Digital Elevation Model) in river basin. Therefore, this study aims at the determination of river fractal dimension using DEM. In this paper, the main-stream length in river basin was grid-analyzed for each scale(1/5,000, 1/25,000, 1/50,000) and each cell size(5m×5m, 10m×10m, 20m×20m, 30m×30m, 40m×40m, 50m×50m, 60m×60m, 70m×70m, 80m×80m, 90m×90m, 100m×100m, 120m×120m, 150m×150m) using GIS. Also, fractal dimension was derived by analyzing correlation among main-stream lengths, scale, and cell size which were calculated here. The result of calculating fractal dimension for each cell size shows that the fractal dimension on the main-stream length is 1.028.

현재의 디지털 통신시스템은 매우 다양한 디지털 변조방식을 채택하고 있다. 이러한 통신시스템에서는 인접채널에 대한 간섭을 최대한 줄이기 위해서 필연적으로 선형 전력증폭기를 요한다. 선형 전력증폭기는 매우 다양한데 그 중에서 전방궤환 전력증폭기는 구조상 광대역이면서 선형화 정도가 매우 우수하다. 전방궤환 전력중폭기에 사용되는 지연선로의 손실로 인하여 전체효율이 감소한다. 본 논문에서는 이러한 지연선로를 손실이 매우 작은 지연필터를 사용함으로써 효율과 선형성을 동시에 개선하였다. 측정된 결과 ACLR이 약 17.43dB 개선되었으며 이것은 지연필터를 사용함으로써 2.54dB 더 개선되었음을 나타낸다.

토양수분의 공간적 분포를 예측하기 위하여 지표면 곡률관련인자, 지형흐름인자, 태양에너지 복사인자들을 계산하였다. GPS와 토양수분측정기를 활용한 산지유역에서의 토양수분측정은 토양수분의 공간적 분포자료의 구축을 가능하게 했다. 측정된 토양수분자료와 토양수분 추정인자 사이의 상관관계를 분석하였다. 다중회귀분석을 통한 토양수분 추정인자와 토양수분의 공간적 분포상황에 대한 검토는 수치고도모형(DEM)의 분석을 통한 토양수분 추정능력의 가능성과 한계성을 보여주었

단일 흐름 기법과 다방향 흐름 기법의 장점을 선택적으로 고려하여 기존 알고리즘의 약점을 보완하기 위한 분포형 수문모형의 흐름 분배 알고리즘을 제안하였다. 상경사(upslop) 격자로부터의 누적 면적을 조절하기 위해 공간적으로 변화된 흐름 분배 상수가 도입되었다. 또한 실제 수로망을 표현하기 위해 수로형성면적(channel initiation threshold area; CIT) 개념을 확장하여 흐름 분배 알고리즘에 결합시켰다. 실제 유역에 대한 적용 결

Before some experiments were carried out with analog bandpass filter which used for filtering the noise included in sound source signal. And this filter was constituted by condenser, register and operational amplifier. Hut these elements made the phase characteristics to differentiate in each sensing channel and cause a little of measurement error. We made new measurement system that was substituted digital filter for the analog filter in order to develop the optimal system which could find the time delay between each sensors with high accuracy. This paper describes the new system's constitution and the function of each parts. Specially three digital filters were designed and applied to the digital signal processing Part. And a series of experiments were carried out with the source＇s distance 9.53meters and the random bearing interval within the limits of 0˚ ~ 180˚. As a result, we have recognized that the accuracy of measurements were differentiated by the methods what kind of digital filter were adopted. And we have confirmed the facts that IIR LPF was suitable for sound source's bearing measurement and FIR LPF reduced the range measurement error.

This study is to develop the technology and the ways of the practical use of the integrated digital map of and Electronical Navigational Chart(ENC) and Digital Terrain Map(DTM) for the effective and scientific based conservation, development and management. In this study, as preliminary studies to make eventual integrated maps, the concept of coastal areas are defined and the characteristics of digital maps developed by Korean Geography Institute and National Marine Investigation Institute are carefully analyzed. A test coastal map was developed based on the integrated digital map, a high resolution satellite image and Global Positioning System. Results from the edge matching analysis of coastal lines shows 8 meters difference in maximum. The problems, causes and solutions for the edge matched differences are described. Furthermore, the practical value of utilization, future use and various field of application are described based on the integrated digital map data base of coastal area.

Radar image data were collected through the on-line data acquisition system of A/D converter and personal computer, and the image was restorated on CRT or plotter after digital image processing of the data. The digital image processing system which was developed for this study, consisted of some kinds of software as follows : rearrangement, transformation, and enhancement of the image data in real space or frequency space by Fourier transform, edge detection of the image, compact processing, state inferential processing, and so on. Since the image of PPI radar sweeps from the center to the circumference of a circle, the image within a given period has the shape of fan. Therefore the acquired data were transformed to have the same interval as that of data in outmost concentricity. The results of various image processing methods using transformed data were better than those of the methods using original data.