• 한국환경복원기술학회지
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• 제17권5호
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• pp.19-28
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• 2014

Given the structure of Korean mountains, it is more appropriate to apply the relative elevation method than the absolute elevation method. However, so far there were not suitable quantitative methodologies to analyze relative elevation, these analytical concepts were difficult to be utilized in urban environmental planning. This study suggested three methods for analyzing relative elevation, and one method for setting the analytical scope of relative elevation by calculating terrain relief. The results showed that the procedure considering 500m radius of each point and standardizing to 30% of the 7th height ridge was the most effective method to extract the local topography. This methodology is the quantitative tool to be able to conserve local important hills and ridges, and apply to fields of urban environmental planning and ecological restoration, especially urban ecological network.

• 대한조선학회논문집
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• 제60권5호
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• pp.305-319
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• 2023

This study focuses on measuring the relative wave elevation around the KSUPRAMAX-O ship and comparing it with numerical analysis results (potential and computational fluid dynamics). The relative wave elevation is a good indicator of the pressure distribution on the ship's surface, which is affected by the ship's motion, incident waves, and distributed waves. Prior to measuring the relative wave elevation, a comparative test was conducted on resistance type, capacitance type, and ultrasonic type wave probe to measure the relative wave elevation, and it was confirmed that the resistance type wave probe was suitable for measuring the relative wave elevation. A model test was performed at low speed and design speed using resistance type wave probe and compared with the results of numerical analysis result. As for the motion response, it was confirmed that the result of experiments and the result of the numerical analysis were in good agreement. The relative wave elevation showed a similar trend between the experiment and the computational fluid dynamics, but the potential analysis result showed a difference from the experiment in design speed.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.101-111
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• 2023

Many spoofing detection studies have been conducted to cope with the most difficult types of deception among various disturbances of GPS, such as jamming, spoofing, and meaconing. In this paper, we propose a spoofing detection scheme based on elevation masked-relative received power between GPS L1 and L2 signals in a system using a multi-band array antenna. The proposed scheme focuses on enabling spoofing to be normally detected and minimizes the possibility of false detection in an environment where false alarms may occur due to pattern distortion among elements of an array antenna. The pattern distortion weakens the GPS signal strength at low elevation. It becomes confusing to detect a spoofing signal based on the relative power difference between GPS L1 and L2, especially when GPS L2 has weak signal strength. We propose design parameters for the relative power threshold including beamforming gain, the minimum received power difference between L1 and L2, and the patch antenna gain difference between L1 and L2. In addition, in order to eliminate the weak signal strength of GPS L2 in the spoofing detection process, we propose a rotation matrix that sets the elevation mask based on platform coordinates. Array antennas generally do not have high usefulness in commercial areas where receivers are operated alone, but are considered essential in military areas where GPS receivers are used together with signal processing for beamforming in the direction of GPS satellites. Through laboratory and live sky tests using the device under test, the proposed scheme with an elevation mask detects spoofing signals well and reduces the probability of false detection relative to that without the elevation mask.

• 대한조선학회지
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• 제19권4호
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• pp.53-59
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• 1982

Relative bow-motions of a ship in wave are investigated by using linear theory. The relative displacement is assumed to be composed of incident wave elevation, motion response, dynamic swell-up and ship wave elevation. Radiation problem is solved by distributing sources on the hull surface and wave elevation in a uniform stream is obtained by integrating Havelock's function with centerplane source distributions. Relative displacements for I.T.T.C. S7-175 model are calculated. Dynamic swell-ups make the relative displacement larger except small heading angles. Amplitudes of relative motion on weather-side are generally larger than those on lee-side. Ship wave elevations in a uniform stream also give considerable contributions and our calculations are verified to be reasonable in comparison with experimental results.

• 한국해양공학회지
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• 제36권1호
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• pp.1-10
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• 2022

Recently, as the offshore structures are operated in the deep-sea oil fields, interest in the analysis of relative wave elevation around platforms is increased. In this study, it is examined how the analysis results differ depending on the characteristics of the wave probe when interpreting the relative wave elevation in the model test. First, by conducting the wave probe comparison experiment in the two-dimensional wave tank, it is confirmed how the measured values differ according to the type of wave probe for the same physical phenomenon. Two types of wave probe are selected, the resistance type and the capacitance type, and the causes of the difference in measured values is studied. After that, the model test of the semi-submersible platform is conducted to investigate the relative wave elevation. Relative wave elevation is measured with the wave probes used in the wave probe comparison experiment and analyzed to estimate the asymmetric factor and the extreme upwell. The results between the two types of wave probes are compared, and qualitative study for the cause of the difference is conducted by photographing the physical phenomenon using a high-speed camera. Through the above study, it is confirmed that the capacitance type wave probe shows a larger measured value than the resistance type under the breaking-wave condition, and the same results are obtained for the asymmetric factor and the extreme upwell. These results is thought to be due to the difference in the measurement principle between wave probes, which is whether or not they measured water bubbles. This implies that the model test should be conducted using appropriate wave probes by considering the physical phenomenon to be analyzed.

• 한국조경학회지
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• 제25권3호
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• pp.177-185
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• 1997

Hibiscus syriacus were surveyed to study the growing temperature, relative humidity and growing responses shown at different elevations of Kangwon Province, and results of the assessment are summarized as follows 1. Growing responses as represented by leaf length, leaf width, shoot length, number of flowers and flowering duration, were decreased as the elevation increased, while the degree of defoliation was increased. 2. The important factor determining the growing responses to the elevation was the maximum and minimum temperatures, particularly those of July, August, and September. 3. The aphid occurrence on Hibiscus syriacus decreased as the elevation increased. Leading factor determining the population was relative humidity which increased as the elevation increased.

• 수산해양기술연구
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• 제22권2호
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• pp.31-35
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• 1986

A bore is a transition between different uniform flows of water. If a long wave of elevation travels in shallow water it steepens and forms a bore. The bore is undular if the change in surface elevation of the wave is less than 0.28 of the original depth of water. This paper describes the growth of an undular bore from a long wave which forms a gentle transition between a uniform flow and still water. A physical account of its development is followed by the results of numerical calculations. Finite-difference approximations are used in the partial differential equations of motion. For undular bores, numerical calculations show that (i) the relationship between relative elevation and relative velocity given by long wave theory is approached for an undular bore, (ii) the amplitude of first crest of an undular bore approaches a finite limit approximately at an exponential rate, and (iii) the distance between the first two crests increases without bound, approximately logarithmically.

• 국제초고층학회논문집
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• 제6권1호
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• pp.83-89
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• 2017

Due to the time-dependent properties of materials, structures, and loads, accurate time-dependent effects analysis and precise construction controls are very significant for rational analysis and design and saving project cost. Elevation control is an important part of the time-dependent construction control in supertall structures. Since supertall structures have numerous floors, heavy loads, long construction times, demanding processes, and are typically located in the soft coastal soil areas, both the time-dependent features of superstructure and settlement are very obvious. By using the time-dependent coupling effect analysis method, this paper compares Shanghai Tower's vertical deformation calculation and elevation control scheme, considering foundation differential settlement. The results show that the foundation differential settlement cannot be ignored in vertical deformation calculations and elevation control for supertall structures. The impact of foundation differential settlement for elevation compensation and pre-adjustment length can be divided into direct and indirect effects. Meanwhile, in the engineering practice of elevation control for supertall structures, it is recommended to adopt the multi-level elevation control method with relative elevation control and design elevation control, without considering the overall settlement in the construction process.

• 약학회지
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• 제41권6호
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• pp.789-796
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• 1997

The purpose of this study was to determine the effect of sulfinpyrazone on fumonisin $B_1$-induced elevation of free sphingoid bases in LLC-$PK_1$ cells. Fumonis ins are a family of mycotoxins produced by the fungi Fusarium moniliforme which is common contaminant in corn. Fumonisins are also potent inhibiors of sphingosine and sphinganine N-acyltransferases (ceramide synthases), key enzymes in sphingolipid metabolism resulting in the elevation of free sphinganine. The cytosolic concentration of fumonisin B1 was known to be closely proportional to the elevation of free sphinganine in LLC-PK1 cells [Yoo, H.-S., Norred, W.P., Wang, E., Merrill, A.H., Jr., and Riley, R.T. (1992) Toxicol. Appl.Pharmacol. 114. 9-15]. Sulfinpyrazone, an anion transport inhibitor, reduced the elevated level of free sphinganine resulting from fumonisin B1 inhibition of de novo sphingolipid biosynthesis. Fumonisin B1 at a concentration of 20${\mu}$M showed approximately 120pmol/$10^6$ cells relative to 3-10pmol/$10^6$ cells in control cultures, and sulfinpyrazone at a concentration of 200${\mu}$M partially reversed the increased level of free sphinganine induced by fumonisin $B_1$ down to normal level after exposure to fumonisin $B_1$ for 8 to 24hr. However, the reduced effect of sulfinpyrazone on the fumonisin $B_1$-induced elevation of intracellular sphinganine was not shown after 24hr. Fumonisin $B_1$ exposure to LLC-PK1 cells for 36 and 48hr showed approximately 74 and 80pmol per $10^6$ cells relative to 82 and 76pmol,respectively, in fumonisin $B_1$ plus sulfinpyrazone-treated cultures. Sulfinpyrazone-induced less elevation of free sphinganine in confluent cells after exposure to fumonisin $B_1$ suggested that either sulfinpyrazone may block the availability of fumonisin $B_1$ to cells or act on the fumonisin $B_1$ interaction with ceramide synthase.

• 대한원격탐사학회지
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• 제37권5_1호
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• pp.1043-1059
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• 2021

식량자원의 확보와 환경생태계에 매우 중요한 요소인 산림과 농경지는 정기적인 모니터링이 요구된다. 농림 위성 영상 자료는 우리나라의 기존 산림 및 농경지 모니터링 방법의 보완재로 효과적으로 활용될 것으로 예상되고 있다. 농림위성의 발사 이전에 사전연구로써 목표 수직기하정확도 산정을 위해 수치표고모델 분석을 수행하였다. 특히 농림위성의 주요 관심 지역인 우리나라 산악지역과 농경지의 특성을 고려하여, 경사도와 식생에 따른 분석을 수행하였다. 공주, 제주 그리고 삼척 지역에 대하여 Shuttle radar topography mission digital elevation model과 Copernicus digital elevation model를 가을과 겨울에 촬영한 드론 LiDAR 수치표면모델 그리고 국토지리정보원 5 m 수치지형모델을 기준으로 평균 상대오차를 비교했다. 그 결과 Shuttle radar topography mission digital elevation model은 8.35, 8.19, 그리고 7.49 m의 상대오차를 나타냈으며, Copernicus digital elevation model는 각각 5.65, 6.73, 그리고 7.39 m의 상대 고도 오차를 나타냈다. 남한 전체에 대하여 Shuttle radar topography mission digital elevation model과 Copernicus digital elevation model를 국토지리정보원 5 m 수치지형모델을 기준으로 지형 경사에 따른 상대 고도 오차를 나타냈다. 그 결과 경사도 0°~5° 사이에서 Shuttle radar topography mission digital elevation model과 Copernicus digital elevation model의 상대 고도 오차는 각각 약 3.62와 2.52 m로 Shuttle radar topography mission digital elevation model의 오차가 더 큰 것으로 산출되었다. 하지만 경사도가 증가함에 따라 이러한 양상은 반전되어 경사도 35° 이상에서는 각각 10.16, 그리고 11.62 m 로 Copernicus digital elevation model의 상대오차가 더 크게 나타났다.