• Geomechanics and Engineering
• /
• v.18 no.6
• /
• pp.651-659
• /
• 2019

The IB-SEM numerical method combines the spectral/hp element method and the rigid immersed boundary method. This method avoids the problems of low computational efficiency and errors that are caused by the re-division of the grid when the solids move. Based on the Fourier transformation and the 3D immersed boundary method, the 3D IB-SEM system was established. Then, using the open MPI and the Hamilton HPC service, the computational efficiency was increased substantially. The flows around a cylinder and a sphere were simulated by the system. The surface of the cylinder generates vortices with alternating shedding, and these vortices result in a periodic force acting on the surface of the cylinder. When the shedding vortices enter the flow field behind the cylinder, a recirculation zone is formed. Finally, the three-dimensional pore flow was successfully investigated.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.32 no.6
• /
• pp.1127-1137
• /
• 2022

Cryptographic analysis and decryption technology utilizing the parallel operation of GPU has been studied in the direction of shortening the computation time of the password analysis system. These studies focus on optimizing the code to improve the speed of cryptographic analysis operations on a single GPU or simply increasing the number of GPUs to enhance parallel operations. However, using a large number of GPUs without optimization for data transmission causes longer data transmission latency than using a single GPU and increases the overall computation time of the cryptographic analysis system. In this paper, we investigate GPUDirect RDMA and related technologies for high-performance data processing in deep learning or HPC research fields in GPU clustering environments. In addition, we present a method of designing a high-performance cryptanalysis system using the relevant technologies. Furthermore, based on the suggested system topology, we present a method of implementing a cryptanalysis system using password cracking and GPU reduction. Finally, the performance evaluation results are presented according to demonstration of high-performance technology is applied to the implemented cryptanalysis system, and the expected effects of the proposed system design are shown.

• Coupled systems mechanics
• /
• v.8 no.2
• /
• pp.99-109
• /
• 2019

This work investigates the accuracy and performance of a $FE^2$ multi-scale implementation used to predict the behavior of composite materials. The equations are formulated assuming the small deformations solid mechanics approach in non-linear material models with hardening plasticity. The uniform strain boundary conditions are applied for the macro-to-micro transitions. A parallel algorithm was implemented in order to solve large engineering problems. The scheme proposed takes advantage of the domain decomposition method at the macro-scale and the coupling between each subdomain with a micro-scale model. The precision of the method is validated with a composite material problem and scalability tests are performed for showing the efficiency.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.885-888
• /
• 2008

In recent years, the terminology "High-Performance Concrete(HPC)" has been introduced into the construction industry. Most high-performance concretes have a high cementitious content and a low water-cementitious material ratio. The proportions of the individual constituents vary depending on local preferences and local materials. Therefore, many trial batches are usually necessary before a successful mix is developed. The objective of this experiments is to investigate the fundamental properties of high performance concrete based binary cimentitious materials such as ordinary portland cement and ground granulated blast furnace slag. The results from the study will be utilized as the basic data and guideline in making standard mixproportions and the manufacture, construction work and quality control of HPC

• KIPS Transactions on Computer and Communication Systems
• /
• v.9 no.5
• /
• pp.113-120
• /
• 2020

KISTI(Korea Institute of Science and Technology Information) provides HPC(High Performance Computing) service to users of university, institute, government, affiliated organization, company and so on. The NURION, supercomputer that launched its official service on Jan. 1, 2019, is the fifth supercomputer established by the KISTI. The NURION has 25.7 petaflops computation performance. Understanding how supercomputing services are used and how researchers are using is critical to system operators and managers. It is central to monitor and analysis network traffic. In this paper, we briefly introduce the NURION system and supercomputing service network with security configuration. And we describe the monitoring system that checks the status of supercomputing services in real time. We analyze inbound/outbound traffics and abnormal (attack) IP addresses data that are collected in the NURION supercomputing service network for 11 months (from January to November 1919) using time series and correlation analysis method.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.10
• /
• pp.231-238
• /
• 2019

Analyzing next-generation genome sequencing data in a conventional way using single server may take several tens of hours depending on the data size. However, in order to cope with emergency situations where the results need to be known within a few hours, it is required to improve the performance of a single genome analysis. In this paper, we propose a parallelized method for pre-processing genome sequence data which can reduce the analysis time by utilizing the big data technology and the highperformance computing cluster which is connected to the high-speed network and shares the parallel file system. For the reliability of analytical data, we have chosen a strategy to parallelize the existing analytical tools and algorithms to the new environment. Parallelized processing, data distribution, and parallel merging techniques have been developed and performance improvements have been confirmed through experiments.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.7
• /
• pp.209-216
• /
• 2023

Modern HPC systems are equipped with many-core CPUs with dozens of cores. When performing parallel I/O in such a system, there is a limit to scalability due to the problem of the LRU lock management policy of the Linux system. The study proposes an improved FinerLRU to solve this problem. Our new FinerLRU improves the parallel write performance of file systems using the buffer cache through granular lock management by increasing the number of LRU locks upto the maximum number of cores. The proposed method was implemented in Linux 5.18.11, and the performance was measured on two types of CPUs, Intel Icelake Xeon and Intel Knights landing, with different characteristics, and it was found that a performance improvement of about two times can be obtained in both types of systems.

• Korean Journal of Microbiology
• /
• v.51 no.2
• /
• pp.126-132
• /
• 2015

Three different methods (simple washing of plastic and pulp sample, washing after direct heating of the diapers, and the heating after washing of plastic and pulp sample) were carried out to decrease total coliforms and heterotrophic plate count (HPC) in the diaper's plastic and pulp. Plastic and pulp samples were obtained from diaper by treatment with 10% $CaCl_2$ and 4% sea salt water, dilution with 1,000 ml tap water, and draining by using sieves. Three times washing was the most appropriate for the reduction of microorganisms in plastic and pulp. By three times washing, the number of total coliforms in the plastic and pulp samples showed 92.8% and 99.8% of decrease, respectively, and the number of HPC showed 97.3% of decrease in the plastic and 98.5% of decrease in the pulp. The washing after direct heating of the fecal contaminated diapers was not effective because HPC in the plastic and pulp samples were still detected about 2-3 log CFU/g in the plastic and 1-2 log CFU/g in the pulp, respectively, even after heating at $60^{\circ}C$, $80^{\circ}C$, $100^{\circ}C$ for 12 h. Meanwhile, total coliforms and HPC were completely sterilized at $80^{\circ}C$ for 4 h by heating after washing of plastic and pulp samples, suggesting that this method was the most appropriate method for the reduction of microorganisms in plastic and pulp obtained from fecal contaminated diapers.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.5
• /
• pp.413-418
• /
• 2001

In this paper, we propose a new camera calibration method which is based on a fuzzy model instead of a physical camera model of the conventional method. The camera calibration is to determine the correlation between camera image coordinate and real world coordinate. The camera calibration method using a fuzzy model can not estimate camera physical parameters which can be obtained in the conventional methods. However, the proposed method is very simple and efficient because it can determine the correlation between camera image coordinate and real world coordinate without any restriction, which is the objective of camera calibration. With calibration points acquired out of experiments, 3-D real world coordinate and 2-D image coordinate are estimated using the fuzzy modeling method and the results of the experiments demonstrate the validity of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.10
• /
• pp.250-258
• /
• 2019

Due to the problems associated with the aging of industrial complexes, research on the decline of industrial complexes is being conducted. In the case of decline, it is necessary to not respond immediately, but with a crisis, it is necessary to minimize the impact on the industrial complex through preemptive responses to the external environment and internal changes. Therefore, it is necessary to develop a crisis index that can systematically predict and evaluate changes in the industrial complex. In this research, a method for extracting the crisis index of an industrial complex is developed. We derive performance measures for developing the crisis index, deriving the relative importance of performance measures based on the analytical hierarchy process. Because units of performance measurement are different, a normalization method is developed to sensitively reflect change. Based on the relative importance and normalized values of the performance measures, the crisis index of the industrial complex is developed and applied to a national industrial complex in order to verify its applicability.