• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.135-136
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• 2015

컴퓨터 생성 홀로그램(CGH: computer generated hologram) 기법은 기존의 광학계 장치와 변수들을 수학적으로 모델링하여 일반 범용 컴퓨터(PC: personal computer)로도 디지털 홀로그램을 생성할 수 있는 기술이다. 이 기술은 디지털 홀로그램의 해상도와 3D 물체의 광원 수에 따라 알고리즘의 연산량이 좌우되기 때문에, 실용적인 사용을 위해서 알고리즘의 연산량을 낮추거나 하드웨어의 연산 속도를 높이는 연구가 필수적이다. 본 논문에서는 초다광원 3D 물체의 디지털 홀로그램을 고속으로 생성할 수 있는 방법을 제안한다. 제안하는 방법은 한 개의 서버 PC와 다수의 클라이언트 PC들로 구성되어 있으며, 이들은 일반적으로 사용되는 범용 GPU (graphic processing unit)가 장착되어 있다. 서버에서 3D 물체의 광원을 스캔하여 데이터화 하고, 클라이언트 PC들의 연산 능력에 따라 광원 데이터를 분할하여 클라이언트들에게 각각 전송한다. 각각의 클라이언트들은 전송받은 데이터를 이용해 다중 GPU 기반의 CGH 연산을 수행하여 간섭 패턴들을 생성하고, 생성된 패턴들은 다시 서버 PC로 재전송된다. 서버 PC로 재전송 된 패턴들이 하나로 누적되면 디지털 홀로그램이 생성된다. 본 실험에서, 기존의 방법으로는 139,655개의 광원에 대해 $1,024{\times}1,024$ 해상도의 홀로그램을 생성하는데 약 2,250 ms가 걸린 반면, 제안하는 방법은 약 478 ms의 속도로 생성할 수 있음을 확인하였다.

• Geophysics and Geophysical Exploration
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• v.18 no.2
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• pp.74-84
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• 2015

To yield physically meaningful images through elastic reverse-time migration, the wavefield separation which extracts P- and S-waves from reconstructed vector wavefields by using elastic wave equation is prerequisite. For expanding the application of the elastic reverse-time migration to anisotropic media, not only the anisotropic modelling algorithm but also the anisotropic wavefield separation is essential. The anisotropic wavefield separation which uses pseudo-derivative filters determined according to vertical velocities and anisotropic parameters of elastic media differs from the Helmholtz decomposition which is conventionally used for the isotropic wavefield separation. Since applying these pseudo-derivative filter consumes high computational costs, we have developed the efficient anisotropic wavefield separation algorithm which has capability of parallel computing by using GPUs (Graphic Processing Units). In addition, the highly efficient anisotropic elastic reverse-time migration algorithm using MPI (Message-Passing Interface) and incorporating the developed anisotropic wavefield separation algorithm with GPUs has been developed. To verify the efficiency and the validity of the developed anisotropic elastic reverse-time migration algorithm, a VTI elastic model based on Marmousi-II was built. A synthetic multicomponent seismic data set was created using this VTI elastic model. The computational speed of migration was dramatically enhanced by using GPUs and MPI and the accuracy of image was also improved because of the adoption of the anisotropic wavefield separation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.144-149
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• 2002

This paper presents a technique for real time multiprocessor parallel processing to develop an avionic system computer(ASC) which integrates the avionics control, navigation and fire control, cursive and raster graphic symbol generation into one line replaceable unit. The proposed method has optimal performance by adopting a logically asymmetric structure between four 32bit RISC processors based on the master-slave multiprocessing, a tightly coupled interaction level with the time shared common bus and global memory, and an efficient bus arbitration algorithm. The ASC has been verified through a series of flight tests. The relevant tests also have been rigorously conducted on the prototype ASC such as electrical test, environmental test, and electromagnetic interference test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.1
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• pp.17-23
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• 2014

Graphics processing units (GPUs) are ideal for solving problems involving parallel data computations. In this study, the GPU is used for effectively carrying out a multi-body dynamic simulation with particle dynamics. The Hilber-Hushes-Taylor (HHT) implicit integration algorithm is used to solve the integral equations. For detecting collisions among particles, the spatial subdivision algorithm and discrete-element methods (DEM) are employed. The developed program is verified by comparing its results with those of ADAMS. The numerical efficiencies of the serial program using the CPU and the parallel program using the GPU are compared in terms of the number of particles, and it is observed that when the number of particles is greater, more computing time is saved by using the GPU. In the present example, when the number of particles is 1,300, the computational speed of the parallel analysis program is about 5 times faster than that of the serial analysis program.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.135-145
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• 2000

Manufacturing Message Specification (MMS) is designed as a communication standard protocol, ISO/IEC 9506, on factory automation for messaging between heterogeneous programmable unit controller, PLC, NC, Robot, of different vendors on the networks. MMS is also a standard protocol of OSI reference model application layer, In this paper, we show an implementation of MMS over TCP/IP using ANSI-C programming language on the unix environment, and make java classification using java native interface (NJI) with MMS library. The use of java classification provides a basic environment ot overcome a difficult programming with different MMS application programming interface (MMS-I) which requires a siklled programming technique of graphic user interface (GUI). In this paper, we implement a MMS application program of the automated assembly model for printed circuit board based on WWW which shows the operation, control and monitoring of real manufacturing device (RMD) with web browser providing users for consistent user interface.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.11
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• pp.381-394
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• 2022

Recently, due to the personalization and customization of data, Internet-based services have increased requirements for real-time processing, such as real-time AI inference and data analysis, which must be handled immediately according to the user's situation or requirement. Real-time tasks have a set deadline from the start of each task to the return of the results, and the guarantee of the deadline is directly linked to the quality of the services. However, traditional container systems are limited in operating real-time tasks because they do not provide the ability to allocate and manage deadlines for tasks executed in containers. In addition, tasks such as AI inference and data analysis basically utilize graphical processing units (GPU), which typically have performance impacts on each other because performance isolation is not provided between containers. And the resource usage of the node alone cannot determine the deadline guarantee rate of each container or whether to deploy a new real-time container. In this paper, we propose a monitoring technique for tracking and managing the execution status of deadlines and real-time GPU tasks in containers to support real-time processing of GPU tasks running on containers, and a node list management technique for container placement on appropriate nodes to ensure deadlines. Furthermore, we demonstrate from experiments that the proposed technique has a very small impact on the system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.1-9
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• 2000

In the recent day, the necessity and the effective usage are increased rapidly, and it is applied in many other fields as well as in the field of ortho-photo map. In this study, we extract each objects on the aerial image and automatically classify graphic information to produce digital map using only digital ortho-image without particular drawing devices for producing digital map. For this purpose, we have applied a lot of the image processing techniques and fuzzy theory, classified outline and lane of road and building, and had each layer according to each feature. Especially, in the case of the building, the outer vector lines extracted by pixel unit at the building were very complex, but we have developed the program to be expressed by I-dimensional linear type between building corners. In the result of this study, we could not extract and recognize all of the object on the image all together, but we have got the error within 50cm using semi-automatic technique. Therefore, this method will be used effectively in producing 1/5,000 digital map.

• Journal of the Korean Regional Science Association
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• v.8 no.1
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• pp.31-50
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• 1992

The aim of this paper is to define major factors influencing land development of each of major uses (residential, commercial, industrial) in the process of rapid urban expansion. The main hypothesis of this study is that land use changing patterns are directed by supply side of land managed to public policies rather than demand side. The graphic analysis is applied to relationships between urban growth and land development process of each use and between land development project managed to public policies and land development process. Public and land development projects and zonning protection seem to be major roles of land supply and main determinants of urban spatial structure. Location factors for land development of each uses are selected in 23 variables. Factor analysis is applied to test correlation between variables in 1971 and 1981. Factor structure between two years is similar, but progressive processing of functional separation is derived such as intensive land use is grouped, different location between residential and industrial use is deep. Dependent variables are standardized to logarithm of land development of each use per unit vacant land in two periods, between 1971 and 1980 year and between 1981 year. Correlation analysis between 6 dependent variables and 23 location factors in each years are applied. Major factors of each use are selected in criteria such as high correlation with dependent variables, low correlation between independent variables and common application in two periods. As the result, major factors for residential land development are Land Readjustment Project (LRP), percent of total zoned area in residential zone, residential floor space density per available area, percent of total area in industrial use; for commercial development is distance to CBD, percent of total area in commercial use, residential floor space density per available area in each year, and volumn rate of industrial use; for industrial use is percent of total area of industrial use is percent of total area of industrial use, Industrial Estate Project (IES), LRP, and distance from CBD. Land development pattern of each use between two periods are slightly different. So 6 equation is derived from appling backward method of regession. Adjusted multiple R squares of all is more than 0.5 and those equation is statistically significant and valuable to assist urban land use forecasting.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.41-47
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• 2014

In this paper, we implemented a CUDA Fortran parallel program to run the CFD_NIMR model on GP-GPU's, which simulates air diffusion on urban terrains. A GP-GPU is graphic processing unit in the form of a PCI card, and a general calculation accelerator to perform a large amount of high speed calculations with low cost and electric power. The GP-GPU gives performance enhancement of speed by 15 times to compare the Nvidia Tesla C1060 GPU with Intel XEON 2.0 GHz CPU. In addition, the program on a GP-GPU shows efficient performance compared to an MPI parallel program on multiple CPU's. It is expected that a proposed programming method on the GP-GPU parallel program can be used for numerical models with a similar structure.

• Journal of the Korea Society of Computer and Information
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• v.27 no.2
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• pp.1-8
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• 2022

In this paper, we design and implement a GPU-based parallel algorithm to effectively solve the traveling salesman problem through an ant color system. The repetition process of generating hundreds or thousands of tours simultaneously in TSP utilizes GPU's task-level parallelism, and the update process of pheromone trails data actively exploits data parallelism by 32x32 thread blocks. In particular, through simultaneous memory access of multiple threads, the coalesced accesses on continuous memory addresses and concurrent accesses on shared memory are supported. This experiment used 127 to 1002 city data provided by TSPLIB, and compared the performance of sequential and parallel algorithms by using Intel Core i9-9900K CPU and Nvidia Titan RTX system. Performance improvement by GPU parallelization shows speedup of about 10.13 to 11.37 times.