• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.405-409
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• 2007

Each class in remotely sensed imagery has different spectral and spatial characteristics. Natural features have relatively smaller spatial changes than spectral changes. Meanwhile, urban area in which buildings, roads, and cars are included is inclined to face more changes of spatial variation than spectral one. This study aims to propose the new urban complexity index (UCI) based on the 3D DWT computation of remotely sensed imageries considering these characteristics. And then we analyze relation between index and land cover map. The 3DWUCI values are related to class and the indices of urban area are greater than natural area. The proposed UCI could be used to express effectively the standard of urban complexity over a wide area.

• 대한원격탐사학회지
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• 제7권1호
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• pp.45-67
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• 1991

An overview is given on stochastic techniques with which remotely sensed data may be used together with ground measurements for purposes of state estimation and prediction. They can explicitly account for spatiotemporal differences in measurement characteristics between ground measurements and remotely sensed data, and are suitable for highly variant space or space-time processes, such as atmosperic processes, which may be viewed as (containing) a random process. For state estimation of static ststems, optimal linear estimation is described. As alternatives, various co-kriging estimation techniques are also described, including simple, ordinary, universal, lognormal, disjunctive, indicator, and Bayesian extersion to simple and lognormal. For illustrative purposes, very simple examples of optimal linear estimation and simple co-kriging are given. For state estimation and prediction of dynamic system, distributed-parameter kalman filter is described. Issues concerning actual implemention are given, and with application potential are described.

• 전자공학회논문지B
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• 제32B권9호
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• pp.1171-1180
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• 1995

In this paper, we present a 3-D object recognition system in which the 3-D Hough transform domain is employed to represent the 3-D objects. In object modeling step, the features for recognition are extracted from the CAD models of objects to be recognized. Since the approach is based on the CAD models, the accuracy and flexibility are greatly improved. In matching stage, the sensed image is compared with the stored model, which is assumed to yield a distortion (location and orientation) in the 3-D Hough transform domain. The high dimensional (6-D) parameter space, which defines the distortion, is decomposed into the low dimensional space for an efficient recognition. At first we decompose the distortion parameter into the rotation parameter and the translation parameter, and the rotation parameter is further decomposed into the viewing direction and the rotational angle. Since we use the 3-D Hough transform domain of the input images directly, the sensitivity to the noise and the high computational complexity could be significantly alleviated. The results show that the proposed 3-D object recognition system provides a satisfactory performance on the real range images.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.252-255
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• 2005

가스터빈 엔진은 작동시간이 축적됨에 따라 엔진 주요부품의 성능이 점차적으로 저하되며, 내부구성부품 사이에 결함이 발생하기도 한다. 이러한 엔진의 손상여부를 진단하기 위해 가스경로해석(GPA, Gas Path Analysis)이 사용되고 있다. 본 연구에서는 상용 프로그램에 의존하지 않고, 각 성능변수들과 측정 변수들과의 열역학적 민감도를 이용하여 엔진성능진단 코드를 개발하였으며, 스마트무인기용 터보축 엔진에 적용하여 엔진의 단일 성능 저하를 예측하여 보았다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.289-292
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• 2005

가스터빈 엔진은 운용시간이 축적됨에 따라 압축기, 연소기, 터빈 등 엔진의 여러 핵심 구성요소의 성능이 저하하게 된다. 따라서, 가스터빈 엔진의 운용에 있어서 높은 신뢰성과 운용비용의 최소화는 엔진 제작자나 사용자 모두에게 있어 중요한 문제이다 본 연구에서는 상용 프로그램에 의존하지 않고, 각 성능 변수들과 측정 변수들과의 열역학적 민감도를 이용하여 엔진성능진단 코드를 개발하였으며, 터보축 엔진에 적용하여 엔진의 단일 성능 저하를 예측하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.248-251
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• 2005

본 연구에서는 가스 터빈 엔진의 결함에 의해 나타나는 엔진의 성능 저하를 진단하는 기법을 연구하였다. 대상 엔진을 모델화하기 위해 상용 프로그램 GSP를 이용하여 저하된 성능 진단을 위한 변수들을 추출하였으며 이를 바탕으로 Health Monitoring을 위한 Virtual Sensor Model을 구축하였다. 단일 결함과 복합 결함을 예측하기 위한 방법으로 Multiple Linear Regression기법과 가중치를 이용한 기법을 도입하여 엔진 구성품의 결함 위치 및 결함 정도를 예측하였다.

• 대한기계학회논문집A
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• 제20권2호
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• pp.540-552
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• 1996

In this paper, a compensation method of disturbance using a disturbance observer is proposed for a force control of a pneumatic robot manipulator. The generated torque by a pneumatic actuator can be estimated based on the pressure signals. The inner torque control system is constructed by feeding back the generated torque to improve the dynamic characteristics of the actuator. In order to reduce the influence of disturbances comprising friction torque, parameter variations of plant and environment and so on, the reaction torque control system is constructed with a disturbance observer which estimates the disturbances based on the reference input to the inner torque control system and the reaction torque sensed with a forced sensor. From some simulations and experiments, it is confirmed that the proposed control system is effective to improve the robustness for the friction torque and the parameter change of object in the force control of a pneumatic robot manupulator.

• 한국추진공학회지
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• 제10권3호
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• pp.82-89
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• 2006

최근 가스 터빈 엔진의 설계에 있어서 엔진 운용 및 정비에 소요되는 비용은 중요한 설계변수로 대두되었다. 이에 따라 엔진의 유지 및 보수가 조립상태에서 이루어져야 한다는 개념이 확대되고 있으나, 실제로 이것은 엔진의 상태를 정확히 예측할 수 있을 때에만 가능한 것이다. 따라서 본 연구에서는 항공기에 장착/운용 중인 각 성능요소들을 측정하고 분석하여 엔진 성능을 진단하는 가스경로해석과 퍼지로직을 적용한 엔진 성능진단 코드를 개발하였으며, 이를 스마트 무인기용 터보축 엔진에 적용하여 지상 정지 상태에서의 엔진의 단일 성능저하를 정량적으로 예측하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.459-462
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• 2006

The diffuse attenuation coefficient for down-welling irradiance ($K_d$) is an important parameter for ocean studies including remote sensing applications. For the vast ocean, ocean color remote sensing is the only possible means to get the fine-scale measurements of $K_d$. To develop a technique of estimating $K_d$ from remotely sensed data, the following underwater optical parameters (absorption coefficient (a), attenuation coefficient (c), scattering coefficient (b), diffuse attenuation coefficient ($K_d$), etc.) have been studied. For this research we conducted the field campaign around the Yellow Sea at $8{\sim}9$ June, 2006. We obtained a set of underwater optical parameter data: down-welling irradiance ($E_d$), up-welling irradiance ($E_u$) and up-welling radiance ($L_u$) using TriOS optical sensors and a, c coefficient using Spectral Absorption and Attenuation Meter (AC-S). We then derived $K_d$ values from $E_d$ for each depth.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.247-268
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• 2011

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting interval varies according to the type of application. Such considerations require an application-specific, parameter tuning paradigm allowing us to maximize energy conservation prolonging the operational network lifetime. In this paper, we propose a reporting interval adaptive, sensor control platform for energy-saving data gathering in wireless sensor networks. The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to application-dependent or time-varying, reporting interval requirements. The proposed sensor control platform is based upon a two phase clustering (TPC) scheme which constructs two types of links within each cluster - namely, direct link and relay link. The direct links are used for control and time-critical, sensed data forwarding while the relay links are used only for multi-hop data reporting. Sensors opportunistically use the energy-saving relay link depending on the user reporting, interval constraint. We present factors that should be considered in deciding the total number of relay links and how sensors are scheduled for sensed data forwarding within a cluster for a given reporting interval and link quality. Simulation and implementation studies demonstrate that the proposed sensor control platform can help individual sensors save a significant amount of energy in reporting data, particularly in dense sensor networks. Such saving can be realized by the adaptability of the sensor to the reporting interval requirements.