• 한국정보과학회논문지:시스템및이론
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• 제31권3_4호
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• pp.195-203
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• 2004

볼륨프로는 일반 PC상에서도 실시간 볼륨렌더링이 가능하도록 고안된 하드웨어이다. 그러나 볼륨프로는 직교투영(orthographic projection) 기능만 제공하기 때문에 가상 내시경과 같이 투시투영 (perspective projection)이 필요한 분야에는 이용할 수 없다. 이런 문제를 해결하기 위해 볼륨 데이터를 여러 개의 슬랩(slab)으로 분할하여 투시투영을 근사 하는 방법이 소개되었으나 이 방법은 시각 절두체에 포함되지 않은 부분까지 렌더링 하기 때문에 처리시간이 길어지는 문제가 있다. 본 논문에서는 볼륨프로의 크로핑(cropping) 기능을 이용하여 볼륨 데이타를 여러 개의 서브볼륨으로 분할함으로써 효율적인 투시투영이 가능하도록 하는 방법을 제안한다. 이 방법은 시각 절두체(view frustum)에 포함되는 부분만 렌더링하므로 슬랩을 이용하는 기존 방법과 동일한 화질을 가지면서 처리시간을 단축시킨다.

• 호남수학학술지
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• 제24권1호
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• pp.9-23
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• 2002

For a closed densely defined linear operator T on a Hilbert space H, let ${\prod}$ denote the function which corresponds to T, the orthogonal projection from $H{\oplus}H$ onto the graph of T. We extend some ordinary norm ineqralites comparing ${\parallel}{\Pi}(A)-{\Pi}(B){\parallel}$ and ${\parallel}A-B{\parallel}$ to the Schatten p-norm where A and B are bounded operators on H.

• 대한의용생체공학회:의공학회지
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• 제32권1호
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• pp.15-24
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• 2011

While Compton imaging is recognized as a valuable 3-D technique in nuclear medicine, reconstructing an image from Compton scattered data has been of a difficult problem due to its computational complexity. The most complex and time-consuming computation in Compton camera reconstruction is to perform the conical projection and backprojection operations. To alleviate the computational burden imposed by these operations, we investigate a rebinning method which can convert conical projections into parallel projections. The use of parallel projections allows to directly apply the existing deterministic reconstruction methods, which have been useful for conventional emission tomography, to Compton camera reconstruction. To convert conical projections into parallel projections, a cone surface is sampled with a number of lines. Each line is projected onto an imaginary plane that is mostly perpendicular to the line. The projection data rebinned in each imaginary plane can then be treated as the standard parallel projection data. To validate the rebinning method, we tested with the representative deterministic algorithms, such as the filtered backprojection method and the algebraic reconstruction technique. Our experimental results indicate that the rebinning method can be useful when the direct application of existing deterministic methods is needed for Compton camera reconstruction.

• 한국정보처리학회논문지
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• 제6권5호
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• pp.1219-1224
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• 1999

This paper derived Montgomery's parallel algorithms for modular multiplication based on Walter's and Iwamura's method, and compared data dependence graph of each parallel algorithm. Comparing the result, Walter's parallel algorithm has small computational index in data dependence graph, so it is selected and used to computed spatial and temporal pipelining diagrams with each projection direction for designing expansible bit-level systolic array. We also evaluated internal operation of proposed expansible systolic array C++ language.

• Communications for Statistical Applications and Methods
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• 제15권1호
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• pp.87-94
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• 2008

Andrews (1972) proposed to combine trigonometric functions to represent n observations of p variates, where the coefficients in linear sums are taken from the values of corresponding observation's respective variates. By viewing Andrews' plot as a collection of n trajectories of p-dimensional objects (observations) as a weighting point loaded with dimensional weights moves along a certain path on the hyper-dimensional sphere, we develop graphical techniques for further uses in data visualization. Specifically, we show that the parallel coordinate plot is a special case of Andrews' plot and we demonstrate the versatility of Andrews' plot with a projection pursuit engine.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
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• pp.36-38
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• 2000

An optoelectronic database filter chip for high performance database computers and applications is proposed. The proposed device is designed to perform the selection and projection operations of relational database operation on-the-fly in page-parallel manner to increase the overall performance of a database system. The device utilizes CMOS smart pixel array consists of detector and combinational logic circuit to perform the selection and projection operation.

• 대한공간정보학회지
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• 제13권1호
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• pp.55-61
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• 2005

정사영상 생성, 도시 공간의 모형차 등 도면화의 다양한 응용분야에 적용을 위해서는 위성영상으로부터 수치고도모형을 생성하는 것은 중요하며, SPOT-5, IKONOS, QUICKBIRD, ORBVIEW 등의 고해상도 위성영상은 효율적이고 경제적으로 수치고도모형을 생성할 수 있는 정보를 제공하고 있다. 그러나, 이들 고해상도 위성영상으로부터 수치고도모형을 생성하기 위해서는 센서모형화, 에피폴라 영상 생성 그리고 영상정합에 대한 사전지식이 필요하다. 이들 중 에피폴라 영상생성은 중요한 인자이며 이에 대한 연구는 아직 미흡한 실정이다. 뿐만 아니라, IKONOS 위성영상으로부터 수치고도모형을 생성하는 연구는 다항식비례모형에 기반한 연구가 주로 이루어졌다. 이에 본 연구에서는 센서 독립적이면서 적은 수의 기준점만으로 센서모형화와 에피폴라 영상생성이 가능한 평행투영모형을 이용하여 수치고도모형을 생성하는 일련의 처리과정을 새롭게 제안하였다. 제안된 방법론은 IKONOS 위성영상을 이용하여 적용하고 평가하였다.

• 건축역사연구
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• 제15권3호
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• pp.27-42
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• 2006

Many contemporary architectural avant gardes tend to use painting as a medium to create architecture which goes beyond the rationalized spatial conception of modem architecture represented by perspectivism. They produce non perspective drawings to represent spatial Ideas, and expand it through poetic imagination to create an unexpected architectural form and space. This paper attempts to analyze the historical origin and background of dominance of drawing in the production of architecture. It was with the invention of perspective that architectural representation became important tool for architectural production. Thereafter, drawing was considered prior to actual building and architecture was considered a three dimensional realization of two dimensional drawing. Modernist avant gardes such as Cubism shattered the rationalized pictorial space of perspective and found a new pictorial space. They tried to extend it to three dimensional space through parallel projection largely based on the Hildebrand's theory of pure visibility. However, due to the ambiguity of the position of the viewing subject, their attempts could not succeed in creating a new architecture. The new architectural avant garde of the 70's rediscovered the early 20th century avant gardes in their attempt to create a new architecture which can register the fragmented spatial condition of contemporary society, and used painting as a medium to create architecture. Their difference from the early avant gardes was that they used poetic imagination rather than parallel projection in the process of projecting three dimensional space and form from the painting. However, their architecture cannot escape the scopic field of perspectivism in that they rely on the picture plane and the distance between object and viewing subject. Therefore, I conclude that in order to create architecture which goes beyond the rationalized space of modern architecture, it is necessary to resort to other tradition of modern architecture than visual one.

• 대한공간정보학회지
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• 제6권2호
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• pp.119-132
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• 1998

지형 및 공간에 관한 많은 양의 정보들은 축척 또는 활용목적 등에 따라 분류되어 다양한 형태의 지도로 만들어지고 있다. 그러나 단일 투영법을 근거로 생산되는 지도가 축척 및 활용목적 등의 다양한 요구조건을 만족시키는 데에는 적합하다고 할 수 없다. 따라서 본 논문에서는 중 대 축척인 1/50,000, 1/25,000, 1/5,000, 1/1,000 지도를 제작하는데 활용되고 있는 기존의 TM 투영법에 대해서 다면체 투영법과 비교 분석하여 다면체 투영법의 활용가능성을 확인해 보고자 하였다. 연구의 수행방식은 타원체면에서 자오선 호장, 평행권 호장 그리고 타원체 면적을 계산하고, 이들 값을 TM과 다면체투영법을 활용하여 직교 평면에 투영하고 타원체 및 투영평면에서 투영 왜곡량을 산출하였다. 또한 지도의 축척별 오차의 허용범위를 규정하고, 두 가지의 투영법에 따른 왜곡량을 지도의 축척별 오차의 허용범위를 결정하였다.

• 대한수학회지
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• 제57권3호
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• pp.617-640
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• 2020

In this paper, we introduce a parallel iterative method for finding a common fixed point of a finite family of Bregman strongly nonexpansive mappings in a real reflexive Banach space. Moreover, we give some applications of the main theorem for solving some related problems. Finally, some numerical examples are developed to illustrate the behavior of the new algorithms with respect to existing algorithms.