• Journal of Computational Design and Engineering
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• 제1권2호
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• pp.140-151
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• 2014

Storing, and the loading and unloading of materials at production sites in the manufacturing sector for mass production is a critical problem that affects various aspects: the layout of the factory, line-side space, logistics, workers' work paths and ease of work, automatic procurement of components, and transfer and supply. Traditionally, the nesting problem has been an issue to improve the efficiency of raw materials; further, research into mainly 2D optimization has progressed. Also, recently, research into the expanded usage of 3D models to implement packing optimization has been actively carried out. Nevertheless, packing algorithms using 3D models are not widely used in practice, due to the large decrease in efficiency, owing to the complexity and excessive computational time. In this paper, the problem of efficiently loading and unloading freeform 3D objects into a given container has been solved, by considering the 3D form, ease of loading and unloading, and packing density. For this reason, a Group Packing Approach for workers has been developed, by using analyzed truck packing work patterns and Group Technology, which is to enhance the efficiency of storage in the manufacturing sector. Also, an algorithm for 3D packing has been developed, and implemented in a commercial 3D CAD modeling system. The 3D packing method consists of a grouping algorithm, a sequencing algorithm, an orientating algorithm, and a loading algorithm. These algorithms concern the respective aspects: the packing order, orientation decisions of parts, collision checking among parts and processing, position decisions of parts, efficiency verification, and loading and unloading simulation. Storage optimization and examination of the ease of loading and unloading are possible, and various kinds of engineering analysis, such as work performance analysis, are facilitated through the intelligent 3D packing method developed in this paper, by using the results of the 3D model.

• 한국음향학회지
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• 제19권1호
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• pp.61-66
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• 2000

본 논문에서는 다중 3차원 근거리표적의 위치를 효과적으로 추정하는 기법을 제안하였다. 제안한 기법은 세 개의 부분 센서배열을 이용하여 기존의 3D MUSIC에서의 3차원 탐색을 3번의 1차원 탐색으로 대치함으로써 연산량을 감소시켰다. 각각의 부분센서배열에서 얻은 센서신호로부터 표적이 원거리에 있다고 가정하고 원거리 입체각을 추정하면 추정된 입체각은 실제 근거리 표적의 위치인 방위각, 고각, 거리의 함수로 주어진다. 그러므로 세 개의 부분센서배열로부터 얻은 세 개의 함수를 연립하여 풀면 실제 근거리표적의 위치를 추정할 수 있다. 또한 다중 표적의 경우, 추정치에 대하여 3차원 MUSIC 스펙트럼 값을 비교함으로써 연관 문제를 해결하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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• pp.139-142
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• 2000

$\mu$BGA(Ball Grid Array) is growing in response to a great demand for smaller and lighter packages for the use in laptop, mobile phones and other evolving products. However it is not easy to find its defect by human visual due to in very small dimension. From this point of view, we are interested its development of a vision based automated inspection algorithm. For this, first a 2D view of $\mu$BGA is described under a special blue illumination. Second, a notation-invariant 2D inspection algorithm is developed. Finally a 3D inspection algorithm is proposed for the case of stereo vision system. As a simulation result, it is shown that 3D defect not easy to find by 2D algorithm can be detected by the proposed inspection algorithm.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.54-59
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• 2004

We suggest a 3D vision inspection algorithm which is based on the external shape feature. Because many electronic parts have the regular shape, if we have the database of pattern and can recognize the object using the database of the object s pattern, we can inspect many types of electronic parts. Our proposed algorithm uses the geometrical pattern matching method and 3D database on the electronic parts. We applied our suggested algorithm fer inspecting several objects including typical IC and capacitor. Through the experiments, we could find that our suggested algorithm is more effective and more robust to the inspection environment(rotation angle, light source, etc.) than conventional 2D inspection methods. We also compared our suggested algorithm with the feature space trajectory method.

• 한국통신학회논문지
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• 제32권8C호
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• pp.782-787
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• 2007

본 논문은 Givens 회전시킨 입력벡터들을 이용하여 오차 제곱을 최소화하는 고속 알고리즘을 정규화하는 D(Diagonal)-QR-RLS 알고리즘을 제안하고 특징을 해석한다. 이 알고리즘은 계산량이 O(N)이다. 또한 직접적으로 TDL 필터의 계수를 구할 수 있는 장점이 있다. 그리고 제안된 정규화 알고리즘은 NLMS 알고리즘과 유사한 형태를 취하지만 NLMS 알고리즘 보다 우수한 수렴특성을 가지고 있음을 컴퓨터 모의실험을 통하여 확인하였다.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2002년도 춘계학술발표논문집(하)
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• pp.901-906
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• 2002

본 논문은 신속조형(RP: rapid prototyping) 시스템에서 사용되며 3D 기하학적 형상 모델을 가지고 있는 STL(standard transform language)에 워터마크를 삽입하는 방법에 관한 연구이다. 제안된 알고리즘은 3D 형상 데이터의 왜곡이 전혀 없이 패싯(facet, mesh)의 버텍스(vertex) 영역에 워터마크를 삽입한다. 기존의 알고리즘으로 STL에 워터마크를 삽입할 경우, 패싯의 저장순서를 변경하는 단순한 공격으로도 워터마크가 제거된다. 제안된 알고리즘은 패싯의 저장 순서 변경과 같은 공격에 대한 강인성을 가질 뿐만 아니라, 비가시성(invisibility)도 충족한다. 제안된 알고리즘으로 STL 3D 형상에 워터마크를 삽입하고 추출하는, 실험 결과들은 3D 원형상을 전혀 왜곡하지 않고 워터마크의 삽입과 추출이 가능함을 보여준다.

• 대한기계학회논문집A
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• 제34권8호
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• pp.971-980
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• 2010

이 논문은 모바일 로봇이 고정 장애물 또는 움직이는 장애물이 존재하는 환경에서 장애물을 회피하며 운행될 수 있는 제어 알고리즘을 연구하였다. 이 제어 알고리즘은 $D^*$ 알고리즘과, 충돌 위험도 퍼지로직, 이동로봇의 행동결정 퍼지로직을 사용하여 전역경로계획과 지역경로계획을 수행한다. $D^*$ 알고리즘에는 로봇이 이동하는 2 차원 공간을 정방형 격자 분활하여 적용한다. 이 알고리즘은 파이썬 프로그래밍 언어와 이동로봇의 운동방정식을 사용한 시뮬레이션을 통해 검증하였다. 시뮬레이션 결과를 통해 알고리즘을 적용하여 로봇이 이동하는 장애물을 피하거나 모르는 고정 장애물을 피하면서 원하는 위치로 이동하는 것을 볼 수 있다.

• Journal of Biosystems Engineering
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• 제23권4호
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• pp.381-390
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• 1998

An algorithm to extract the 3-D geometric information of a static object was developed using a set of 2-D computer vision system and a laser structured lighting device. As a structured light pattern, multi-parallel lines were used in the study. The proposed algorithm was composed of three stages. The camera calibration, which determined a coordinate transformation between the image plane and the real 3-D world, was performed using known 6 pairs of points at the first stage. Then, utilizing the shifting phenomena of the projected laser beam on an object, the height of the object was computed at the second stage. Finally, using the height information of the 2-D image point, the corresponding 3-D information was computed using results of the camera calibration. For arbitrary geometric objects, the maximum error of the extracted 3-D feature using the proposed algorithm was less than 1~2mm. The results showed that the proposed algorithm was accurate for 3-D geometric feature detection of an object.

• ETRI Journal
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• 제45권6호
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• pp.1035-1045
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• 2023

We propose a novel graphics processing unit (GPU) algorithm that can handle a large-scale 3D fast Fourier transform (i.e., 3D-FFT) problem whose data size is larger than the GPU's memory. A 1D FFT-based 3D-FFT computational approach is used to solve the limited device memory issue. Moreover, to reduce the communication overhead between the CPU and GPU, we propose a 3D data-transposition method that converts the target 1D vector into a contiguous memory layout and improves data transfer efficiency. The transposed data are communicated between the host and device memories efficiently through the pinned buffer and multiple streams. We apply our method to various large-scale benchmarks and compare its performance with the state-of-the-art multicore CPU FFT library (i.e., fastest Fourier transform in the West [FFTW]) and a prior GPU-based 3D-FFT algorithm. Our method achieves a higher performance (up to 2.89 times) than FFTW; it yields more performance gaps as the data size increases. The performance of the prior GPU algorithm decreases considerably in massive-scale problems, whereas our method's performance is stable.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.851-856
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• 1987

A direct computation algorithm of two dimensional fast Fourier transform (2D-FFT) is considered here for implementation in mesh connected multiprocessor array of both a 2D-toroidal and a rectangular type. Results are derived for a hardware algorithm including data allocation and interprocessor communications. A performance comparison is carried out between the proposed direct 2D-FFT computation and the conventional one to show that a new algorithm gives higher speedup under a reasonable assumption on the speeds of operations.