• Communications of the Korean Mathematical Society
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• v.18 no.2
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• pp.263-280
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• 2003

We prove weighted L$^{p}$ estimates with respect to the non-isotropic norm for the (equation omitted)-equation on real ellipsoids, where weights are powers of the distance to the boundary. The non-isotropic norm is smaller than the usual norm, by a factor which is equal to the distance to the boundary in the complex tangential component and which is equal to the m-th root of the distance to the boundary in the complex normal component. Here n is the maximal order of contact of the boundary of the real ellipsoid with complex analytic curves.

• Korean Journal of Geomatics
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• v.3 no.1
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• pp.7-14
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• 2003

For GIS to land and sea in Korea, GIS on land was almost completed with big cities by NGIS(National Geographic Information System) business. However, MGIS(Marine Geographic Information System) being constructed by the National Oceanographic Research Institute is still constructing geography information and definition of attribute information and real condition. We are being studied on research to get maximized the ripple effect linking GPS and Navigation techniques on GIS. GPS in accuracy is divided into navigation and precise surveying equipment. Now, GPS technology has been developed very much and low price GPS equipments are introducing. But expense on GPS equipment is high yet. Therefore, GPS equipment for navigation is used on cheap GPS equipment in a car or ship. In this paper, the author used algorithm to convert ellipsoid coordinate between WGS84 and Bessel ellipsoid and to analyze map projection between BESSEL ellipsoid and UTM plane coordinate system. And the author developed ship navigation system with cheap GPS equipment using algorithm of ellipsoid conversion and map projection. The author proposed the necessity on constructing MGIS to manage many ships.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.119-126
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• 2018

In this study, In this study, the Datum Level-based hydrography surveying system and the ellipsoid-based system were analyzed to acquire more consistent depth data. For the study, the ellipsoid-based surveying for hydrography was conducted twice for the same track line. And the depth was calculated by correcting rise and fall of water level (water level change by tidal energy and other marine environmental energies) respectively by the traditional water level correction method and ellipsoidally referenced water level correction method. there is able to check that Ellipsoid-based hydrographic surveying data is more improved than Datum Level-based hydrographic surveying data in aspect of level difference phenomenon in the same area (surveying line). This result shows that if the Ellipsoid-based hydrographic surveying is performed, the sea level change (tidal energy and other marine environmental energy) of the survey area in real time could be reflected to more consistent generating bathymetric data.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.177-182
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• 2015

General method for correcting the distortion caused by the characteristic of the fish-eye lens may be classified in two ways. The first method is a calibration method using a mathematical model taking into account the characteristics of the lens, the second method is a method using only the distortion correction image, regardless of the lens. When considering the characteristics of the lens, calibration equation can be calculated geometrically from the relationship between the three-dimensional real-world coordinates and two-dimensional image coordinates and the parameters of lens. However, it is not suitable for ellipsoid type lens, because of existing research papers have been corrected on the spherical-type fisheye lens. In this paper, we propose a method for correcting geometrically using fish-eye lens as an ellipsoid model. Through a calibration picture, it can be seen that the proposed method is valid.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.116-119
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• 2018

In this paper, we propose a new single-image dehazing method. The proposed method constructs color ellipsoids that are statistically fitted to haze pixel clusters in RGB space and then calculates the transmission values through color ellipsoid geometry. The transmission values generated by the proposed method maximize the contrast of dehazed pixels, while preventing over-saturated pixels. The values are also statistically robust because they are calculated from the averages of the haze pixel values. Furthermore, rather than apply a highly complex refinement process to reduce halo or unnatural artifacts, we embed a fuzzy segmentation process into the construction of the color ellipsoid so that the proposed method simultaneously executes the transmission calculation and the refinement process. The results of an experimental performance evaluation verify that compared to prevailing dehazing methods the proposed method performs effectively across a wide range of haze and noise levels without causing any visible artifacts. Moreover, the relatively low complexity of the proposed method will facilitate its real-time applications.

• Progress in Medical Physics
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• v.19 no.4
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• pp.227-230
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• 2008

The purpose of this study was to design and construct an ultrasound phantom for volume calibration and evaluate the volume measurement accuracy of a 2 dimensional ultrasonic system. Ultrasound phantom was designed, constructed and tested. The phantom consisted of a background material and a target. The background was made by mixing agarose gel with water. A target, made with an elastic material, was filled with water to vary its volume and shape and inserted into background material. To evaluate accuracy of a 2 dimensional ultrasonic system (128XP, ACUSON), three different shapes of targets (a sphere, 2 ellipsoids and a triangular prism) were constructed. In case of ellipsoid shape, two targets, one with same size length and width (ellipsoid 1) and another with the length 2 times longer than width (ellipsoid 2) were examined. The target volumes of each shape were varied from 94cc to 450cc and measurement accuracy was examined. The volume difference between the real and measured target of the sphere shape ranged between 6.7 and 11%. For the ellipsoid targets, the differences ranged from 9.2 to 10.5% with ellipsoid 1 and 25.7% with ellipsoid 2. The volume difference of the triangular prism target ranged between 20.8 and 35%. An easy and simple method of constructing an ultrasound phantom was introduced and it was possible to check the volume measurement accuracy of an ultrasound system.

• Communications for Statistical Applications and Methods
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• v.3 no.2
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• pp.13-19
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• 1996

Cook's distance(Cook, 1997) is one of the most widely used influence measures to assess the influence of single observations or sets of observations in the linear regression model. After computing Cook(1977) suggested guidelines based on a confidence ellipsoid for the regression parameter ${\beta}$. In this paper, we suggest cutoff values for Cook's distance cia Monte Carlo simulation, and compare them with Cook's guidelines. An example based on a real data set is given.

• Progress in Medical Physics
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• v.20 no.4
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• pp.208-215
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• 2009

This study is to compare the accuracy of evaluation regarding the volume of the prostate, which three-dimensional volume rendering was produced the shape of protrusion, by measuring two kinds of craniocaudal length from the top of the protrusion and from the exclusion of the protrusion as the starting points. For the imaginary protrusion prostate models, total of 10 models were roughly made by using devils-tongue jelly and changing each of the 10 ml of capacity from 10 ml to 100 ml. For the protrusion prostate models aimed at estimating the real volume, through 64 cannel computed tomography (CT) and 3.0 tesla magnetic resonance image (MRI) were conducted by planimetry technique from three-dimensional volume rendering. And then we performed to evaluate on significance of these volumes by wilcoxon signed rank test. Also the obtained volumes data by ellipsoid volume formula were measured the volume of protrusion prostate models two times with each method using the two kinds of craniocaudal length from top of the protrusion and from exclusion of the protrusion as the starting points. Finally, the significance of differences using wilcoxon signed rank test was evaluated between the real volume by planimetry technique and the measured volume by ellipsoid volume formula from three-dimensional volume rendering. The average of the protrusion length on the models was $0.90{\pm}0.18\;mm$ in CT and was $0.75{\pm}0.11\;mm$ in MRI. There were not statistically significant difference between MRI and CT from the volume of protrusion prostate models (p=0.414). In MRI (p=0.139) and CT (p=0.057), there were not statistically significant difference between the real volume by planimetry technique and the measured volume by ellipsoid volume from exclusion of the protrusion as the starting points. While, there were statistically significant difference between the real volume by planimetry technique and the measured volume by ellipsoid volume from top of the protrusion as the starting points in MRI (p=0.005) and CT (p=0.005). For the accurate measurement of the protrusion prostate models, the craniocaudal length of the prostate should be measured from the exclusion of the protrusion as the starting points.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.969-975
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• 2002

Visual effects are important cues for providing occupants with virtual reality in a vehicle simulator which imitates real driving. The viewpoint of an occupant is sensitively dependent upon the occupant's posture, therefore, the total human body motion must be considered in a graphic simulator. A real-time simulation is required for the dynamic analysis of complex human body motion. This study attempts to apply a neural network to the motion analysis in various driving situations. A full car of medium-sized vehicles was selected and modeled, and then analyzed using ADAMS in such driving conditions as bump-pass and lane-change for acquiring the accelerations of chassis of the vehicle model. A hybrid III 50%ile adult male dummy model was selected and modeled in an ellipsoid model. Multibody system analysis software, MADYMO, was used in the motion analysis of an occupant model in the seated position under the acceleration field of the vehicle model. Acceleration data of the head were collected as inputs to the viewpoint movement. Based on these data, a back-propagation neural network was composed to perform the real-time analysis of occupant motions under specified driving conditions and validated output of the composed neural network with MADYMO result in arbitrary driving scenario.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.39-46
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• 2004

In the GIS construction to land and sea in Korea, GIS construction on land was completed mostly for big cities by NGIS(National Geography Information System) business. However, Marine GIS being constructed by the National Oceanographic Research Institute is still constructing geography information and definition of attribute information and real condition. We have done researches to get maximized ripple effect linking GPS and Navigation techniques on GIS. GPS in accuracy is divided into navigation and precise surveying equipments. Now, GPS technology has been developed very much and with low price GPS equipments are being introduced. But costs on the GPS equipments are high yet. Therefore, the GPS equipments for navigation can be substituted by cheap GPS equipments in a car or ship. In this paper, the authors developed algorithm to convert ellipsoid coordinate between WGS84 and Bessel ellipsoid and to analyze map projection between BESSEL ellipsoid and UTM plane coordinate system. And the author developed ship navigation system with cheap GPS equipments using algorithm of ellipsoid conversion and map projection. The authors proposed the necessity on constructing Internet GIS to manage many ships.