• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.279-289
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• 2021

GNSS receivers capable of tracking multiple Global Navigation Systems (GNSSs) simultaneously are widely used. In order to estimate accurate user position and velocity, it is necessary to consider the key elements that contribute to the interoperability of the different GNSSs. Typical examples are the time system and the coordinate system. Each GNSS is operated based on its own reference time system depending on when the system was developed and whether the leap seconds are applied. In addition, each GNSS is designed based on its own coordinate system based on earth model constant values. This paper addresses the interoperability issues from the viewpoint of Single Point Positioning (SPP) users utilizing multiple GNSS signals from GPS, GLONASS, BeiDou, and Galileo. Since the broadcast ephemerides of each GNSS are based on their own time and coordinate systems, the time and the coordinate systems should be unified for any user algorithm. For this purpose, this paper proposes a method of converting each GNSS coordinate system into the reference coordinate system through Helmert transformation. The error of the broadcast ephemerides was calculated with the precise ephemerides provided by the International GNSS Service (IGS). The effectiveness of the proposed multi-GNSS correction and transformation method is verified using the Multi-GNSS Experiment (MGEX) station data.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.300-301
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• 2014

Measurement of beam deflection is a common procedure to determine proper behavior of the structure. Either LVDT (Linear Variable Displacement Transformer) or strain gauge is usually used in experiments. A newly developed coordinate reading measurement system can be also applied for the deflection measurements. In this study, an experimental measurement was made on a laboratory size beam specimen to examine the possibility of the use of such coordinate measurement system. Results have shown the possibility of utilizing the new system for beam deflection measurement.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.126-127
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• 2003

In the generalized characteristic coordinate system (GCCS) proposed by Wu and Shi [1], the frame moves at a speed which is a linear combination of the convective speed and the sound speed, thus unifying the classical Eulerian approach, Lagrangian approach, and the unified coordinate system (UCS) of Hui and his co-workers [2]. Here some properties of Euler equations in the GCCS are studied and the advantages of GCCS in capturing expansion fans and shock waves are demonstrated by the results of numerical tests.

• 전자공학회논문지B
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• 제29B권9호
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• pp.59-67
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• 1992

Color image enhancement can be achieved easily by using linear form of coordinate system. But some popular color coordinate systems almost have nonlinear characteristics in the geometric form. In this paper, the proposed coordinate system has pseudo-linear form and based on IHS system which represents human color perception appropriately. And for the image intensity processing, an edge-preserving smoothing algorithm is presented.

• 충청수학회지
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• 제34권4호
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• pp.379-385
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• 2021

We consider the local uniqueness of a catenoid under the condition for the Gaussian curvature analogous to Bianchi surfaces. More precisely, if a nonplanar minimal surface in ℝ³ has the Gaussian curvature $K={\frac{1}{(U(u)+V(v))^2}}$ for any functions U(u) and V (v) with respect to a line of curvature coordinate system (u, v), then it is part of a catenoid. To do this, we use the relation between a conformal line of curvature coordinate system and a Chebyshev coordinate system.

• 한국운동역학회지
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• 제20권2호
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• pp.117-127
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• 2010

The axes of upper forearm coordinate system have been considered as principal axis of each segment which was component of elbow joint. The purpose of this study was to verify whether the mean direction(principal axis) of instantaneous axes of rotation for pure flexion/extension motion coincided with the flexion/extension axis of upper forearm coordinate system. The same procedure was done for pronation/supination motion. Furthermore, it was tested indirectly that there was an interaction effect between the two rotational motions. The results showed that most segment coordinate axes statistically were not consistent with the mean directions of flexion/extension and pronation/supination axes of rotation. From the results, it would be concluded that the ISB coordinate systems was proved to be a little valid for human movement analysis. There also was an effect of pronation/supination angles on flexion/extension motion.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권1호
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• pp.22-30
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• 2003

A Coordinate-Transformation Extended Robust Kalman Filter (CERKF) designed in the Krein space is proposed, and then applied to a nonlinear incoming ballistic missile tracking system with parameter uncertainties. First, the Extended Robust Kalman filter (ERKF) is proposed to handle the nonlinearity of measurement equation which occurs whenever the polar coordinate system is transformed into the Cartesian coordinate system. Moreover, linearization error inevitably occurs and deteriorates the tracking performance, which is considerably reduced by the proposed CERKF. Through the simulation results, we show that the proposed CERKF, which uses the measurement coordinate system, has less RMS error than the previous ERKF which is designed in the Krein space using the Cartesian system. We also verify that the robustness and the stability of the proposed filter are guaranteed in two radars: the phased way radar and the scanning radar

• 한국지리정보학회지
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• 제11권1호
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• pp.178-189
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• 2008

이 연구는 중등교육과정의 지리정보교육에서 경위도 좌표계에 대한 교육 강화의 필요성을 살펴본 것이다. 오늘날 GPS 기반의 위치정보 서비스는 경위도 좌표계의 활용을 크게 증가시키고 있다. 미국과 일본을 비롯한 선진국들은 이미 그들의 중등교육과정에 경위도 좌표와 관련된 내용을 명시하고 있으나 한국의 중등교육과정에서는 경위도 좌표에 대하여 구체적인 교육이 이루어지지 않고 있다. 경위도 좌표의 활용 현황을 알아보기 위해 주요 신문의 기사를 분석한 결과 2000년을 전후하여 경위도 좌표에 관한 내용이 포함된 기사가 꾸준히 증가하고 있음을 확인할 수 있었다. 그리고 상당수의 기사는 위치정보를 경위도 좌표 형식으로 제공하여 독자가 이를 활용할 수 있도록 하고 있다. 교육현장에서 경위도 좌표를 기반으로 공간정보를 활용하기 위한 하드웨어적 환경은 충분히 구축되어 있다. 세계화 시대를 살아갈 학생들이 공간정보를 올바르게 이해하고 활용할 수 있도록 하기 위해서 경위도 좌표계에 대한 구체적인 교육이 필요하다.

• 한국수학사학회지
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• 제25권4호
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• pp.37-51
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• 2012

역사적인 지도제작법에 나타난 좌표계와 수학적 직교좌표계의 발전 과정을 비교하면서 위치를 표시하는 직교좌표계는 수학의 해석기하학과는 상관없이 인간 본연에 내재되어 있었던 공간지각능력의 일환으로 발전되어 왔음을 주장한다. 지도제작법의 발전이 해석기하학의 발명 전후 삼각함수, 로그, 기하학, 미적분학, 통계학 등 수학의 여러 분야와 상호 영향을 미치지만 원점의 표시나 음수 좌표의 사용과 같은 수학적 직교좌표계 자체에 대한 발전은 데카르트의 논문 발표 후 100여년 이상 지난 후에 이루어지는 점, 해석기하학을 발명하는데 공헌한 대부분의 수학자들이 당대의 문제 해결에 집중하면서 직교좌표계에 대한 수학적 설명없이 자연스럽게 사용하였던 점을 바탕으로 이런 결론을 얻는다.

• Tribology and Lubricants
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• 제16권6호
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• pp.432-439
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• 2000

The present work is an attempt to calculate the steady state pressure and perturbed pressure of herringbone grooved journal bearings. A generalized coordinate system is introduced to handle the complex bearing geometry. The coordinates are fitted to the groove boundary and the Reynold's equation is transformed to be fitted to this coordinate system using the Gauss divergence theorem. This method makes it possible to deal with an arbitrary configuration of a lubricated surface. The caharacteristics of finite herringbone groove journal bearing are well calculated using this method.