NPP-VIIRS야간 위성영상과 국지적 공간 통계를 이용한 시가지 추출 가능성 평가

주뢰 ( Lei Zhu ),조대헌 ( Daeheon Cho ),전창우 ( Changwoo Jeon ),이소영 ( Soyoung Lee ) 한국도시지리학회 2016 한국도시지리학회지 Vol.19 No.3

시가지 확산은 도시화나 토지이용변화의 측면에서 지리학 등 학문적인 연구 대상일 뿐만 아니라 도시 계획 및 관리를 위해서도 기본적인 관심사가 된다. 이 연구는 시가지를 파악하기 위한 방법으로 최근 주목 받고 있는 야간 위성영상의 적용 가능성을 살펴보고자 하는데, 특히 한국에서는 거의 활용되지 않은 NPP-VIIRS 데이터에 대한 국지적 공간 통계 분석의 활용 가능성을 평가하였다. 우리나라 중부지방을 대상으로 NPP-VIIRS 데이터와 국지적 공간연관성통계량(Getis and Ord`s G<sub>i</sub>*, local Moran`s I, and Lee`s S<sub>i</sub>*)을 통해 시가지를 추출한 후, 이를 참조 데이터와 비교 검토하였다. 실제 시가지보다 과장될 수 있는 야간 조명의 특성을 고려하여 야간 밝기 값을 그대로 사용하는 경우와 제곱을 통해 값 간의 편차를 더 크게 한 경우를 분석하였다. 추출된 시가지의 전체 면적 및 위치 일치도를 파악한 결과 원래 값 보다는 제곱을 한 경우, 그리고 국지적 공간연관성통계량 중에는 Getis and Ord`s G_i*의 결과가 참조 데이터들과 가장 유사한 것으로 나타났다. 하지만 지역에 따라 면적이나 위치 일치도 등이 차이를 보였는데, 수도권과 같이 도시화 수준이 높은 지역은 원 변수를 제곱한 경우가 더 나은 결과를 나타낸 반면, 지방의 경우는 원 변수를 사용하는 것이 더 나은 결과를 보였다. 하위지역을 별도로 분석한 결과에서는 도시화의 수준이 높은 지역에서 더 나은 결과를 보였지만 더 적합한 변수는 전체 지역을 분석한 결과와는 반대로 나타났다. Built-up area expansion has long been interested in the aspects of urbanization and land use change not only by academic studies on geography, but also by planners to make proper policies. This paper aims to evaluate the feasibility of NPP-VIIRS nighttime light data on built-up area extraction. Spatial statistical methods-local spatial association statistics (local SAS) (Getis and Ord`s G<sub>i</sub>*, Moran`s Ii, and Lee`s S_i*) were applied to extract built-up area with NPP-VIIRS images. Central Korea including capital region, Gangwon, Chungnam (including Daejeon and Sejong) and Chungbuk was taken as the study area. Results of raw value and square value of nighttime light value(digital number) were both considered and the results and accuracies were evaluated with the reference data. The results show that: 1) in general, results of square value are more consistent with the reference data than those of raw value for both area comparison and classification accuracy in central Korea, especially for G_i*; 2) for central Korea analysis, results of highly urbanized regions show a higher accuracy than those less urbanized in general, while the square value results of highly urbanized regions have higher accuracies, and raw value results are more accurate for regions with low urbanization level; 3) for subregional analysis, highly urbanized regions also have a higher accuracy, but contrary to the results of central Korea, raw value results have a higher accuracy in highly urbanized region, while square values perform better in less urbanized region for the urban extraction.

Feature Variable Optimization for Eccentricity Detection in Roll-to-Roll System

Yoonjae Lee(이윤제),Haemi Lee(이해미),Minjee Kim(김민재),Hyun-jin Choi(최현진),Taik-Min Lee(이택민),Changwoo Lee(이창우) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

BIM 사례연구를 통한 건설 PLM 설계에 관한 연구

이언(Eon Lee),강형석(Hyoungseok Kang),이상석(Sangseok Lee),노상도(Sangdo Noh),이창우(KwangMyong lee),이광명(ChangWoo Lee) (사)한국CDE학회 2010 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2010 No.1

Building Information Modeling (BIM) is the virtual representation of the physical and functional characteristics of a facility from inception onward. As such, it serves as a shared information repository for collaboration throughout a facility’s lifecycle. BIM is a new paradigm which can perform a diverse engineering activity such as design, simulation, structure analysis, etc and support a based information model in construction industry. In these days, many construction companies tried to perform a project efficiently by constructing and using BIM and carried out a research related in PMIS(Project Management Information System), etc. But a real case of research focused on 3D modeling object and control and share of engineering information is insufficient. In this research, we suggest an efficient BIM model and information share system based PLM for collaboration based on analyzing and researching a case of constructing BIM when perform construction project.

Dependence of the mechanical properties of nanohoneycomb structures on porosity

Choi, Dukhyun,Lee, Sangmin,Lee, Changwoo,Lee, Pyungsoo,Lee, Junghyun,Lee, Kunhong,Park, Hyunchul,Hwang, Woonbong IOP 2007 Journal of micromechanics and microengineering Vol.17 No.3

<P>Mechanical properties of nanohoneycomb structures are measured for varying porosity (or pore diameter) of the nanohoneycomb structure. The indentation modulus and hardness in the pore direction (or thickness direction) are obtained from indentation tests using a nano-indenter. The bending modulus of the nanohoneycomb structures in the vertical direction relative to the pore (generally along the beam length) is determined from bending tests in AFM. To determine the bending modulus of the nanohoneycomb structures, the area moment of inertia of the nanohoneycomb structure is determined according to the arrangement of the pores. The indentation moduli and the hardness are found to decrease nonlinearly with increasing porosity. The bending moduli of the nanohoneycomb structures also decrease nonlinearly as a function of porosity over a large range. It is made clear that the elastic modulus of a homogenous material can be controlled by changing the pore diameter.</P>

A study on the fire propagation characteristics in large-opening multi-level limestone mines in Korea

Changwoo Lee,Vanduc Nguyen 한국자원공학회 2016 Geosystem engineering Vol.19 No.6

Recently, deployment of large-capacity diesel haulage trucks is rapidly increasing in the domestic large-opening limestone mines due to the high level of operational flexibility. However, in multi-level mines, this trend has raised the serious concern for the risk of diesel vehicle fire. Fire in a deep multi-level mine site is harder to control and likely to develop into disastrous results. Developing the emergency evacuation strategies and controlling the fire should presuppose a knowledge of the fire behavior in mines. This paper aims at studying the behavior of a 25-ton diesel truck fire showing approximately the maximum heat release rate of 30 MW by computational fluid dynamic analysis. Spatial and temporal distributions of the hot air stream, smoke layer, and CO gas layer in multi-level mine sites are evaluated, and the effects of fan operation are scrutinized to find the appropriate fan location and operating mode. In addition, several other aspects of the fire development such as backlayering and throttling effects are also studied. The ultimate goal is to provide fundamental information about fire propagating characteristics in multi-level large-opening underground limestone mines for developing the mine fire evacuation plan and protect the workers’ safety.

Blind Image Deblurring based on Deep Image Prior

Changwoo Lee,Jinwon Choi 대한전자공학회 2022 IEIE Transactions on Smart Processing & Computing Vol.11 No.2

Many studies on image deblurring have been conducted, and deep learning methods for blind image deblurring have received considerable attention due to their good performance. Recently, the SelfDeblur method was proposed for blind image deblurring based on deep image prior (DIP). In the SelfDeblur method, two neural networks for an image generator and a blur kernel generator are learned simultaneously with only one blurry image. This shows the feasibility of blind image deblurring using unsupervised learning, since it requires no training process. In this paper, we propose a method to maximize the performance of blind image deblurring based on DIP. The optimal loss function for deep learning is studied for the SelfDeblur method, and the deblurring performance of the proposed method is stabilized and maximized using the image prior and the kernel prior for the total loss function. Extensive computer simulations show that the proposed method yields superior performance compared to conventional methods.

A Sphere Phantom Approach to Measure Directional Modulation Transfer Functions for Tomosynthesis Imaging Systems

Changwoo Lee,Jongduk Baek IEEE 2016 IEEE transactions on medical imaging Vol.35 No.3

<P>We propose a sphere phantom approach to measure spatially varying directional modulation transfer functions (MTFs) for tomosynthesis imaging systems. Since the reconstructed tomosynthesis images contain significant artifacts, traditional background detrending techniques may not be effective to estimate the background trends accurately, which is essential to acquire sphere only data. A background detrending technique optimized for local volumes with different cone angles is presented. To measure directional MTFs, we calculate plane integrals of ideal sphere phantom and sphere only data. To minimize the effects of the high level of noise in tomosynthesis images, Richardson-Lucy deconvolution with Tikhonov-Miller is used to estimate directional plane spread function (PlSF). Then, directional MTFs are calculated by taking the modulus of the Fourier transform of the directional PlSFs. The measured directional MTFs are compared with the ideal directional MTFs calculated from a simulated point object. Our results show that the proposed method reliably measures directional MTFs along any desired directions, especially near low frequency regions.</P>

Differential regulation of neuronal excitability by nicotine and substance P in subdivisions of the medial habenula

Lee, Changwoo,Lee, Soonje,Woo, Changsu,Kang, Shin Jung,Kim Kwon, Yunhee,Shin, Ki Soon ZOOLOGICAL SOCIETY OF KOREA 2018 ANIMAL CELLS AND SYSTEMS Vol.22 No.3

<P><B>ABSTRACT</B></P><P>The medial habenula (MHb) plays an important role in nicotine-related behaviors, such as aversion and withdrawal. The MHb is composed of distinct subregions with unique neurotransmitter expression and neuronal connectivity. Here, we showed that nicotine and substance P (SP) differentially regulate neuronal excitability in subdivisions of the MHb (ventrolateral division, MHbVL; dorsal division; MHbD and superior division: MHbS). Nicotine remarkably increased spontaneous neuronal firing in the MHbVL and MHbD, but not in the MHbS, which was consistent with different magnitudes of whole-cell inward currents evoked by nicotine in each subdivision. Meanwhile, SP enhanced neuronal excitability in the MHbVL and MHbS. Although the MHbD is composed of SP-expressing neurons, they did not respond to SP. Neurons in the MHbVL increased their firing in response to bath-applied nicotine, which was attenuated by neurokinin receptor antagonists. Furthermore, nicotine addiction and withdrawal attenuated and augmented excitatory SP effects in the MHbVL, respectively. On the whole, we suggest that MHb-involving nicotine-related behaviors might be associated with SP signaling in MHb subdivisions.</P>

Model-Based Winding Tension Profile to Minimize Radial Stress in a Flexible Substrate in a Roll-to-Roll Web Transporting System

Lee, Jongsu,Lee, Changwoo IEEE 2018 IEEE/ASME transactions on mechatronics Vol.23 No.6

<P>In this study, we propose a model-based taper tension profile that minimizes residual and radial stresses. In contrast to the constant torque and hyperbolic taper profile, the developed model can accurately decrease the winding tension depending upon the final decrement set by a user regardless of the maximum wound radius. Moreover, the model steeply decreases the winding tension in comparison to other tension models in the early stage, consequently, decreasing the residual stress and maximum radial stress. A hybrid model that combines the developed and conventional taper tension models is developed to expand the range of application of the model. A winding tension maker that applies the model to the winding tension controller is also developed. A variable transformation model that transforms the input of the developed model (radius ratio) to the winding time, which can be easily obtained without any sensors, is obtained. The developed model and winding tension maker are applied to an industrial roll-to-roll thin film winding machine. It is observed that local deformation in a wound thin film generated by the excessive radial stress is improved. A control technique is selected considering film characteristics, and a winding tension controller is designed using the developed tension models and winding tension maker. The designed winding tension controller decreases the maximum radial stress by 38% when compared to the case before application. Moreover, the winding length with few local deformations increases from 100 to 500 m; this confirms the superiority of the developed model and controller.</P>

Inverse filtering approach to measure directional in-plane modulation transfer function using a sphere phantom for a digital tomosynthesis system

Lee, Changwoo,Baek, Jongduk The Optical Society 2017 Optics express Vol.25 No.15