• 한국지능시스템학회논문지
• /
• 제20권6호
• /
• pp.786-792
• /
• 2010

본 논문은 복잡한 도로 환경에서 차선을 정확하게 찾는 실시간 차선 검출법을 보인다. 기존의 많은 방법들은 대게 후처리 과정에서 차선 안쪽에 존재하는 잡음을 찾아 차선의 위치를 찾지만, 제안하는 방법은 특징 추출 단계에서 가능한 많은 잡음을 제거하므로 후처리 과정에서 검색 영역을 최소화한다. grid기반 모폴로지 연산은 우선 관심영역을 능동적으로 생성한 후, 모폴로지의 닫기 연산을 통해 에지 들을 연결한다. 그리고 방향성 에지 연결 기법을 통하여 유효한 방향에지를 찾고 사전에 구해진 영상 내 차선의 높이와 두 차선 간의 폭 관계를 이용하여 두 개의 차선을 군집화한다. 마지막으로 차선의 색상은 YUV색상 공간에서 두 개의 연결된 에지 안쪽을 검사하여 Bayesian확률 모델을 사용하여 추정한다. 제안하는 방법의 실험 결과는 다수의 불필요한 에지 군집이 존재하는 복잡한 도로 환경에서 효과적으로 도로 에지를 감별하였으며, 제안하는 알고리즘은 해상도 $320{\times}240$ 영상으로 10ms/frame의 속도에서 약92%의 정확도를 보였다.

• ETRI Journal
• /
• 제41권3호
• /
• pp.316-325
• /
• 2019

Accurate suppressive jamming is a prominent problem faced by radar equipment. It is difficult to solve signal detection problems for extremely low signal to noise ratios using traditional signal processing methods. In this study, a joint sensing dictionary based compressed sensing and adaptive iterative optimization algorithm is proposed to counter suppressive jamming in information domain. Prior information of the linear frequency modulation (LFM) and suppressive jamming signals are fully used by constructing a joint sensing dictionary. The jamming sensing dictionary is further adaptively optimized to perfectly match actual jamming signals. Finally, through the precise reconstruction of the jamming signal, high detection precision of the original LFM signal is realized. The construction of sensing dictionary adopts the Pei type fast fractional Fourier decomposition method, which serves as an efficient basis for the LFM signal. The proposed adaptive iterative optimization algorithm can solve grid mismatch problems brought on by undetermined signals and quickly achieve higher detection precision. The simulation results clearly show the effectiveness of the method.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.35-35
• /
• 2023

The main reason for its instability is sediment scouring downstream of hydraulic structures. Both physical and numerical models have been used to investigate the influence of soil properties on scour hole geometry. Nevertheless, no research has been conducted on resistance parameters that affect sedimentation and erosion. In addition, auxiliary structures like wing walls, which are prevalent in many real-world applications, have rarely been studied for their impact on morphology. The hydraulic characteristics of steady flow through a boxed culvert are calibrated using a 3D Computational Fluid Dynamics model compared with experimental data in this study, which shows a good agreement between water depth, velocity, and pressure profiles. Test cases showed that 0.015 m grid cells had the lowest NRMSE and MAE values. It is also possible to quantify sediment scour numerically by testing roughness/d₅₀ ratios (c_s) and diversion walls at a meander flume outlet. According to the findings, c_s = 2.5 indicates a close agreement between numerical and analytical results of maximum scour depth after the culvert; four types of wing walls influence geometrical deformation of the meander flume outlet, resulting in erosion at the concave bank and deposition at the convex bank; two short headwalls are the most appropriate solution for accounting for small changes in morphology. A numerical model can be used to estimate sediment scour at the meander exit channel of hydraulic structures based on the roughness parameter of soil material and headwall type.

• 한국측량학회지
• /
• 제29권4호
• /
• pp.359-365
• /
• 2011

본 연구는 스캔라인 기반의 2차원 이웃 관계를 활용하여 레이블링 알고리즘과 윈도우 기반의 알고리즘을 함께 적용함으로써 항공레이저측량 자료의 지면점과 비지면점을 효과적으로 분리하는 것을 목적으로 한다. 이를 위하여 스캔라인 구조를 바탕으로 최소의 탐색을 통해 점들의 인접 관계를 구축하고, 구축된 인접관계를 기반으로 연결성분 레이블링 알고리즘을 적용하여 항공레이저측량 자료를 지면점과 비지면점으로 분리하였다. 그리고, 모폴로지 필터링을 통해 작은 개체를 추가로 제거하고 거리반비례 추정을 통해 고립 지면점을 복원하여 정확도를 향상시켰다. 다양한 특성을 나타내는 지역에 적용하고 평가한 결과 대부분의 점들이 올바르게 분리 되었고 약97%의 전체 정확도를 도출하였으며, 인접관계 구축 및 데이터 처리 시간이 TIN 또는 격자 구조 자료 구축시간에 비하여 적게 소요되었다.

• 국제초고층학회논문집
• /
• 제6권2호
• /
• pp.139-147
• /
• 2017

Analyzing morphological evolution over a long period of time is deemed an effective way to identify problems occurring in the process of urban development, in addition to achieving a fundamental understanding of socio-cultural changes and growth rooted from the context. As far as the urban morphology is concerned, Hong Kong is characterized by its unique high-density and compact layout patterns, which have aroused the interest of a number of authors in the urban design domain. Whilst an increasing number of redevelopment projects in Hong Kong were criticized for ignoring and destroying the old urban fabric, there is a need for research to investigate the origins and changes of various urban patterns and their implications for society. By employing the theories and techniques of space syntax, this paper accordingly provides a morphological analysis based on the Wanchai District - a 'Segment-line' city, which particularly epitomizes various urban grids of Hong Kong and may have different implications for functional aspects. By axial-mapping the urban layouts of five stages of growth since 1842 and subsequently investigating their spatial and functional transformation over the past 170 years, this paper identifies a series of spatial characteristics underlying different grid patterns, as well as achieves a precise understanding of their ever changing relationship. Based on these understandings, this paper intends to provide valuable reference and guidance for upcoming spatial development in Hong Kong and other regions.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.179-179
• /
• 2016

A radio-frequency (RF) Inductively Coupled Plasma (ICP) torch system was used for boron-nitride nano-tube (BNNT) synthesis. Because of electrodeless plasma generation, no electrode pollution and effective heating transfer during nano-material synthesis can be realized. For stable plasma generation, argon and nitrogen gases were injected with 60 kW grid power in the difference pressure from 200 Torr to 630 Torr. Varying hydrogen gas flow rate from 0 to 20 slpm, the electrical and optical plasma properties were investigated. Through the spectroscopic analysis of atomic argon line, hydrogen line and nitrogen molecular band, we investigated the plasma electron excitation temperature, gas temperature and electron density. Based on the plasma characterization, we performed the synthesis of BNNT by inserting 0.5~1 um hexagonal-boron nitride (h-BN) powder into the plasma. We analysis the structure characterization of BNNT by SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy), also grasp the ingredient of BNNT by EELS (Electron Energy Loss Spectroscopy) and Raman spectroscopy. We treated bundles of BNNT with the atmospheric pressure plasma, so that we grow the surface morphology in the water attachment of BNNT. We reduce the advancing contact angle to purity bundles of BNNT.