• 대한원격탐사학회지
• /
• 제25권6호
• /
• pp.501-505
• /
• 2009

Quasi-linear bright features persistently appeared on ENVISAT ASAR images as well as X-SAR images along the tidal channels in Gyung-Gi Bay, Korea during the ebb tides. These features are induced by spatial backscatter variations caused by surface convergence (divergence) through the interaction between tidal currents and bathymetry. In order to validate this mechanism, a numerical tidal model simulation is performed on the realistic bathymetry with the tidal boundary conditions. The tide model reproduces the current convergence zone along the tidal channel during the ebb tides, which exactly coincides with the location of bright line features on SAR images.

• Current Optics and Photonics
• /
• 제2권6호
• /
• pp.595-605
• /
• 2018

The two-photon process of microscopy provides good spatial resolution and optical sectioning ability when observing quasi-static endogenous fluorescent tissue within an in vivo animal model skin. In order to extend the use of such systems, we developed a two-photon laser scanning microscopy system capable of also capturing $512{\times}512$ pixel images at 90 frames per second. This was made possible by incorporating a 72 facet polygon mirror which was mounted on a 55 kRPM motor to enhance the fast-scan axis speed in the horizontal direction. Using the enhanced temporal resolution of our high-speed two-photon laser scanning microscope, we show that rapid processes, such as fluorescently labeled erythrocytes moving in mouse blood flow at up to 1.2 mm/s, can be achieved.

• 한국조경학회지
• /
• 제22권2호
• /
• pp.39-52
• /
• 1994

Existing natural resources were analyzed in regional scale in order to suggest natural park guidelines as a previous step of conservation plan. Results of both existing natural resources and land potentiality in preceding paper were combined to suggest comprehensive and qualitative method for understanding of natural land. Regional characteristics of natural park were, then, analyzed by this method, and specific planning guidelines were discussed. The existing natural resources were analyzed by the degree of location quotient, which were found by comparison of the grade of vegetation naturalness and the bio-physical land unit in preceding paper. Then, allowance of existing natural resources was identified, and importance of protection was described based on this result. The bio-physical land unit on Tokyo Province was found to be composed by smaller land units, which had a variety of relationship with grade of vegetation naturalness: from the specific(1st) to many stages(5th). This meant a characteric of each land unit. By this combined approach, the characteristics and spatial distribution of natural land were discussed in the regional scale, and characteristic of nateral park were analyzed in terms of natural location. National park were located in the land unit where both land capability and importance of portection were the 6th. Quasi national park and 1 province natural park were located in the land unit where land capability was the 6th and importance of protection were the 5th. Seven province natural parks were located in the land unites were both criteria under the 5th were mixed. based on the results of this study, the followings were suggested for specific planning guidelines in the case of Takao quasi nation park: (a) conservative land use within the limit of carrying capacity of this area by the conservation of biotic and abiotic natural resources, (b) conservation of both natural and semi-natural vegetation, (c) utilization of this area as a urban forest.

• 한국지리정보학회지
• /
• 제11권3호
• /
• pp.52-67
• /
• 2008

최근 기상이변으로 인한 이상홍수의 빈번한 발생으로 인해 신속하고 정량적인 강우예측의 필요성이 대두되고 있으며 강우의 거동을 실시간으로 관측하여 예측이 가능한 강우레이더의 활용성이 높아지고 있다. 이와 더불어 1km 해상도의 격자형으로 제공되는 강우레이더를 효과적으로 활용하기 위해 격자단위의 분석이 가능한 분포형 수문모형의 활용이 증가하고 있다. 분포형 수문모형을 활용하기 위해서는 대상 유역에 대한 격자형 공간자료가 요구되며 유출모의의 신뢰도를 높이기 위해서는 현시성 있고 정밀한 자료의 활용이 필요하다. 본 논문에서는 유역면적의 약 2/3가 미계측 지역인 임진강 유역을 대상으로 물리적 기반의 $Vflo^{TM}$ 모형과 가 분포형(Quasi-distributed) 수문모형인 ModClark 모형을 이용하여 홍수유출 모의를 실시하고 결과를 비교하였다. 연구의 공간적 범위를 미계측 지역을 포함한 임진강 전 유역과 비교적 정확하고 현시성 있는 자료의 확보가 가능한 임진강 남한 유역으로 구분하였으며 각 유역에 대해 모의한 모형별 첨두유량과 지체시간을 비교하여 지형매개변수 및 토양매개변수의 불확실성이 유출모의에 미치는 영향을 분석하고 미계측 지역의 유출모의를 위한 효과적인 방안을 제시하였다.

• 지적과 국토정보
• /
• 제49권1호
• /
• pp.157-179
• /
• 2019

역세권 2030청년주택 정책은 역세권 개발이 서울시 내 임대주택 택지를 확보하기 위한 유일한 대안이라는 인식 가운데 기대를 받으며 출범했다. 그러나 임대주택 공급실적은 당초 계획에 미치지 못했고 용도지역체계에 혼란을 줄 수 있다는 비판이 지속적으로 제기되었다. 결국, 역세권 2030청년주택은 시행 후 3년 사이에 운영기준이 6차례 개정되었다. 특히 2018년 10월 이후에는 1년 이내에 큰 폭의 운영기준 개정이 두 차례 이어졌다. 이에 본 연구는 사업가능구역과 용도지역 변경 가능구역의 변화 양상을 분석하여, 지난 운영기준 개정의 방향성 평가와 정책적 시사성을 도출하고자 했다. 공간적 범위 및 구역의 도출에는 명제논리를 활용했다. 이를 위해, 가구(街區) 등 기초자료 정제 및 전처리, 명제별 진리 값 입력, 논리연산 과정을 수행하여 사업가능구역 및 용도지역 변경 가능구역 소속여부를 판별했다. 분석 결과, 1) 사업가능구역은 서울시 외곽의 역세권으로 고르게 분산되면서도 준주거지역과 상업지역으로 집중되는 경향이 있고, 2) 용도지역 변경 가능구역은 준주거지역 변경 가능구역을 중심으로 전반적인 증가추세가 두드러졌다.

• 대한건축학회논문집:계획계
• /
• 제35권5호
• /
• pp.73-83
• /
• 2019

The purpose of this study is to analyze the spatial transformational patterns according to the spectator and the exhibition environment and to examine the role of 'the middle space' organically linking the exhibition space with MoA which is a representative example of 'sequential exhibition space'. The concept of sequential exhibition space in MoA is applied not only to building but also to extended continental concepts including neighborhood. MoA's exhibition space consists of the library area and the exhibition area. In particular, the spaces of library area perform a complex function as a quasi-exhibition space, and the exhibition spaces have variable spatial transformation through an associated structure of the library area and the educational area. The types of exhibition space those constitute the sequential exhibition space of MoA appear as 'Room type', 'Free plan type', and 'Gallery type'. Each exhibition space maintains independence, but it is changed according to the situation of exhibition. The flow is based on the spiral induction around the central void space, but with selective circulation considering the visitors. Therefore, through the transformation of the exhibition area and the division of the flow, the whole museum space appears as the area differentiation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권10호
• /
• pp.4865-4886
• /
• 2017

The user experience of practical indoor power line communication (PLC) applications is greatly affected by the system quality-of-service (QoS) criteria. With a general broadcast-and-multi-access (BMA) relay scheme, in this work we investigate the joint source and relay power optimization of the amplify-and-forward (AF) relay systems used under indoor broad-band PLC environments. To achieve both time diversity and spatial diversity from the relay-involved PLC channel, which is time-varying in nature, the source node has been configured to transmit an identical message twice in the first and second signalling phase, respectively. The QoS constrained power allocation problem is not convex, which makes the global optimal solution is computationally intractable. To solve this problem, an alternating optimization (AO) method has been adopted and decomposes this problem into three convex/quasi-convex sub-problems. Simulation results show the fast convergence and short delay of the proposed algorithm under realistic relay-involved PLC channels. Compared with the two-hop and broadcast-and-forward (BF) relay systems, the proposed general relay system meets the same QoS requirement with less network power assumption.

• Journal of Magnetics
• /
• 제21권3호
• /
• pp.450-459
• /
• 2016

Experimental results and data of numerical simulations are presented, concerning generation of wideband radio frequency (RF) oscillations in a nonlinear transmission line (NLTL) which contains a pre-magnetized core of ferrite material. Emphasis is made on the means for extracting the RF signal from the line, in order to radiate it into free space. Antennas of two types that can be used for the purpose are considered, both featuring a coaxial design. This permits availing of the principal advantages of coaxial systems, such as operation in the mode of a traveling TEM wave; wide range of the transmitted frequencies, and a reasonably simple design. The antennas studied, specifically a disc-cone dipole (DCD) and an impulse reflector antenna ('Half-IRA', or HIRA type) differ significantly in effective width of the radiated spectrum and in spatial characteristics of the radiated field in far region.

• 천문학회지
• /
• 제44권2호
• /
• pp.49-58
• /
• 2011

We calculate the energy spectra of cosmic ray (CR) protons and electrons at a plane shock with quasi-parallel magnetic fields, using time-dependent, diffusive shock acceleration (DSA) simulations, including energy losses via synchrotron emission and Inverse Compton (IC) scattering. A thermal leakage injection model and a Bohm type diffusion coefficient are adopted. The electron spectrum at the shock becomes steady after the DSA energy gains balance the synchrotron/IC losses, and it cuts off at the equilibrium momentum $p_{eq}$. In the postshock region the cutoff momentum of the electron spectrum decreases with the distance from the shock due to the energy losses and the thickness of the spatial distribution of electrons scales as $p^{-1}$. Thus the slope of the downstream integrated spectrum steepens by one power of p for $p_{br}$ < p < $p_{eq}$, where the break momentum decreases with the shock age as $p_{br}\;{\infty}\;t^{-1}$. In a CR modified shock, both the proton and electron spectrum exhibit a concave curvature and deviate from the canonical test-particle power-law, and the upstream integrated electron spectrum could dominate over the downstream integrated spectrum near the cutoff momentum. Thus the spectral shape near the cutoff of X-ray synchrotron emission could reveal a signature of nonlinear DSA.

• 한국전산유체공학회지
• /
• 제6권4호
• /
• pp.26-34
• /
• 2001

The flow past a circular cylinder forced to vibrate transversely is numerically simulated by solving the two-dimensional Navier-Stokes equations modified by the vibration velocity of a circular cylinder at a Reynolds number of 164. The higher-order finite difference scheme is employed for the spatial discretization along with the second order Adams-Bashforth and the first order backward-Euler time integration. The calculated cylinder vibration frequency is between 0.60 and 1.30 times of the natural vortex-shedding frequency. The calculated oscillation amplitude extends to 25% of the cylinder diameter and in the case of the lock-in region it is 60%. It is made clear that the cylinder oscillation has influence on the wake pattern, the time histories of the drag and lift forces, power spectral density and phase diagrams, etc. It is found that these results include both the periodic (lock-in) and the quasi-periodic (non-lock-in) state. The vortex shedding frequency equals the driving frequency in the lock-in region but is independent in the non-lock-in region. The mean drag and the maximum lift coefficient increase with the increase of the forcing amplitude in the lock-in state. The lock-in boundaries are also established from the present direct numerical simulation.