• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.27-35
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• 2015

Increasing the number of GPU (Graphic Processor Unit) cores, the studies on High Performance Computing Platform using GPU have actively been made in recent. This trend has led to the development of GPGPU (General Purpose GPU) and CUDA (Compute Unified Device Architecture) Framework. In this paper, we explain the many benefits of the GPU based system, and propose the ICIDF(Identify Compute-Intensive Data set and Function) methodology to apply GPU technology to legacy military information system for performance improvement. To demonstrate the efficiency of this methodology, we applied this method to AES CPU based program obtained from the Internet web site. Simply changing the data structure made improved the performance of AES program. As a result, the performance of AES based GPU program is improved gradually up to 10 times. Depending on the developer's ability, additional performance improvement can be expected. The problem to be solved is heat issue, but this problem has been much improved by the development of the cooling technology.

• Design & Manufacturing
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• v.1 no.1
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• pp.51-56
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• 2007

As various manufacturing technology of optical glass is developed, the aspheric lenses are supplied to many fields. Electronic or measuring instruments equipped with aspheric lens have recently been used since aspheric lens is more effective than spheric one. However, it is still difficult manufacture glass lens because of high cost and the short life of core. The demands of the aspheric glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. For the mass production of aspheric lens, specific molds with precisely machined cores should be prepared. In order to obtain competitiveness in the field of industrial manufacturing, a reduction in the development period for the batch machining of products is required. It is essential to analyze the stress distribution and deformations of machining system which is used for manufacturing the aspheric lens using FEM software ANSYS. Finite element simulations have been performed in order to study the influence of machining system which is developed in this study on structures. It is very important to understand the structural behavior of machining system. This paper investigated the static analysis and dynamic analysis of machining system for aspheric lens to predict the damage due to loading.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.58-65
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• 2010

Remanufacturing is a process that restores old products to perform like new, while saving energy, reducing consumption of natural resources, and lowering environmental emissions. By extending the product life cycle, remanufacturing approaches enable closed loop material cycles that are ultimately necessary for a sustainable society. This paper provides some description of the current automotive remanufacturing enterprise, with a particular emphasis on key vehicle components that are currently remanufactured. The analysis yields two major conclusions. First, volume of the USA automotive after sales and remanufacturing industry market is estimated. Second, market price of a remanufactured component in the automotive sector is surprisingly uncorrelated with the number of companies engaged in remanufacturing that component - at least for companies registered with the Automotive Parts Remanufacturing Association (ARPA).

• Journal of the Korean Society for Precision Engineering
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• v.30 no.11
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• pp.1139-1145
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• 2013

Machine tools are the cores of industrial development in recent period. It is difficult to develop a system which can do cutting and grinding process in the one system. Hybrid Vertical Grinding System is capable of processing in a single apparatus cutting or grinding. The modal analysis and structural analysis for the development of Hybrid Vertical Grinding System is the first time of domestic work. This paper describes the technologies of Hybrid Vertical grinding machine and intend to introduce the studies in the development of the Hybrid Vertical Grinding System.

• Journal of the Korean Society of Visualization
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• v.2 no.2
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• pp.52-57
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• 2004

The development and interaction of vortices over a delta wing with leading edge extension (LEX) was investigated through off-surface flow visualization using micro water droplets and a laser beam sheet. Angles of attack of $20^{\circ}$ and 24$^{\circ}$ were tested at sideslip angles of $0^{\circ}$, $-5^{\circ}$, and $-10^{\circ}$ The flow Reynolds number based on the main-wing root chord was $1.82{\times}10^{5}$. The wing vortex and the LEX vortex coiled around each other while maintaining comparable strength and identity at a zero sideslip. The increase of angle of attack intensified the coiling and shifted the cores of the wing and LEX vortices inboard and upward. By sideslip, the coiling, the merging and the diffusion of the wing and LEX vortices were increased on the windward side, whereas they were delayed significantly on the leeward side. The present study confirmed that the sideslip angle had a profound effect on the vortex structure and interaction of a delta wing with LEX, which characterized the vortex-induced aerodynamic load.

• Journal of The Korean Astronomical Society
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• v.41 no.5
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• pp.139-145
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• 2008

The molecular cloud, embedding AFGL 2591, has a "head-and-tail" structure with a total mass of ${\sim}\;1800\;M_{\odot}$, about half of the mass (${\sim}\;900\;M_{\odot}$) in the head (size ${\sim}\;1.2\;pc$ in diameter), and another half in the envelope (${\sim}\;3.5\;pc$ in the east-west direction). We found a new cloud in the direction toward north-east from AFGL 2591 (projected distance ${\sim}\;2.4\;pc$), which is probably associated with the AFGL 2591 cloud. The $^{12}CO$ spectrum clearly shows a blue-shifted high-velocity wing at around the velocity $-20\;{\sim}\;-10\;km\;s^{-1}$, but it is not clear whether this high-velocity component has a bipolar nature in our observations. The observed CN spectra also show blue-shifted wing component but the existence of the red-shifted component is not clear, either. In some CN and HCN spectra, the highvelocity components appear as a different velocity component, not a broad line-wing component. The dense cores, traced by CN and HCN, exist in the 'head' of the AFGL 2591 cloud with an elongated morphology roughly in the north-south direction with a size of about 0.5 pc. The abundance ratio between CN and HCN is found to be about 2 - 3 within the observed region, which may suggest a possibility that this core is being affected by the embedded YSOs or by possible shocks from outside.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.3
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• pp.241-247
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• 2014

The voltage source PWM inverter generally used to drive the air conditioning (A/C) fans has been posing a large issue that the bearings in air conditioning fan motors are highly possible to be corroded electrically. Potential difference called shaft voltage is generated between inner and outer rings of the bearings due to inverter switching. The shaft voltage causes bearing lubricant breakdown dielectrically. As a result, bearing current is caused. This current causes the bearing corrosion. In previous work, we demonstrated that the shaft voltage can be reduced by using an insulator inserted between the outer and inner cores of the rotor in an air conditioning fan motor without grounding. This paper proposes the other countermeasure for reducing the shaft voltage in fan motors. The countermeasure which adds a capacitor between the brackets and the stator core is effective even for fan motors with non-insulated rotor. The effectiveness is confirmed by both simulated and experimental results.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.93-100
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• 2008

In this paper, we address a novel simulated annealing(SA)-based test scheduling method for testing network-on-chip (NoC)-based systems-on-chip(SoCs), on the assumption that the test platform proposed in [1] is installed. The proposed method efficiently mixed the rectangle packing method with SA and improved the scheduling results by locally changing the test access mechanism(TAM) widths for cores and the testing orders. Experimental results using ITC'02 benchmark circuits show that the proposed algorithm can efficiently reduce the overall test time.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.6
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• pp.634-646
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• 2015

Coarse-Grained Reconfigurable Architecture (CGRA) is a very promising platform that provides fast turn-around-time as well as very high energy efficiency for multimedia applications. One of the problems with CGRAs, however, is application mapping, which currently does not scale well with geometrically increasing numbers of cores. To mitigate the scalability problem, this paper discusses how to use the SIMD (Single Instruction Multiple Data) paradigm for CGRAs. While the idea of SIMD is not new, SIMD can complicate the mapping problem by adding an additional dimension of iteration mapping to the already complex problem of operation and data mapping, which are all interdependent, and can thus significantly affect performance through memory bank conflicts. In this paper, based on a new architecture called SIMD reconfigurable architecture, which allows SIMD execution at multiple levels of granularity, we present how to minimize bank conflicts considering all three related sub-problems, for various RA organizations. We also present data tiling and evaluate a conflict-free scheduling algorithm as a way to eliminate bank conflicts for a certain class of mapping problem.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.808-816
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• 2016

As the number of CPU/GPU cores and IPs in SOC increases and applications require explosive memory bandwidth, simultaneously achieving good throughput and fairness in the memory system among interfering applications is very challenging. Recent works proposed priority-based thread scheduling and channel partitioning to improve throughput and fairness. However, combining these different approaches leads to performance and fairness degradation. In this paper, we analyze the problems incurred when combining priority-based scheduling and channel partitioning and propose dynamic priority thread scheduling and adaptive channel partitioning method. In addition, we propose dynamic address mapping to further optimize the proposed scheme. Combining proposed methods could enhance weighted speedup and fairness for memory intensive applications by 4.2% and 10.2% over TCM or by 19.7% and 19.9% over FR-FCFS on average whereas the proposed scheme requires space less than TCM by 8%.