• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1784-1787
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• 2010

General Purpose Graphic Processing Unit (GPGPU) computing is a technique that utilizes the high-performance many-core processors of high-end graphic cards for general-purpose computations such as 3D graphics, video/image processing, computer vision, scientific computing, HPC and many more. GPGPUs offer a vast amount of raw computing power, but programming is extremely challenging because of hardware idiosyncrasies. The open computing language (OpenCL) has been proposed as a vendor-independent GPGPU programming interface. OpenCL is very close to the hardware and thus does little to increase GPGPU programmability. In this paper we present how a set of digital camera image signal processing (ISP) filters can be realized efficiently on GPGPUs using OpenCL. Although we found ISP filters to be memory-bound computations, our GPGPU implementations achieve speedups of up to a factor of 64.8 over their sequential counterparts. On GPGPUs, our proposed optimizations achieved speedups between 145% and 275% over their baseline GPGPU implementations. Our experiments have been conducted on a Geforce GTX 275; because of OpenCL we expect our optimizations to be applicable to other architectures as well.

• Korean Journal of Materials Research
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• v.34 no.8
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• pp.395-399
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• 2024

Among various organic materials suitable for silicon-based inorganic-organic hybrid solar cells, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been extensively studied due to its high optical transmittance, high work function, and low bandgap characteristics. The electro-optical properties of PEDOT:PSS have a significant impact on the power conversion efficiency of silicon-organic hybrid solar cells. To enhance the photovoltaic properties of the silicon-organic hybrid solar cells, we developed a method to improve the properties of the PEDOT:PSS film using Ag nanowires (NW) instead of conventional solvent addition methods. The influence of the Ag NW on the electro-optical property of the PEDOT:PSS film and the photovoltaic performance of the silicon-organic hybrid solar cells were investigated. The addition of Ag NW further improved the sheet resistance of the PEDOT:PSS film, enhancing the performance of the silicon-organic hybrid solar cells. The present work using the low sheet resistance PEDOT:PSS layer paves the way to develop simple yet more efficient silicon-organic hybrid solar cells.

• Corrosion Science and Technology
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• v.23 no.4
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• pp.334-342
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• 2024

The need for efficient and sustainable energy storage solutions has emerged due to a rapidly increasing energy demand and growing concerns about environmental issues. Among various energy storage methods, lithium secondary batteries are widely used in a variety of electronic devices such as smartphones, laptops, electric vehicles, and large-scale power storage systems due to their high energy density, long lifespan, and cost competitiveness. Recently, all-solid-state batteries (ASSBs) have attracted great attention because they can reduce the risk of fire associated with liquid electrolytes. Additionally, using high-capacity alternative anodes and cathodes in ASSBs can enhance energy density. However, ASSBs that use solid electrolytes experience a degradation in their electrochemical performances due to resistance at solid-solid interfaces. These interfaces can also result in poor physical contact and the presence of products formed from chemical and electrochemical reactions. Solving this interface problem is a critical issue for the commercialization of ASSBs. This review summarizes interfacial reactions between the cathode and solid electrolyte, along with research aimed at improving these interactions. Future development directions in this field are also discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.337-347
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• 2013

It is generally well-known that the inevitable high power electromagnetic wave affects the malfunction and disorder of electronic equipments and serious damages in electronic communication systems. Hence, it is necessary to take measures against high power electromagnetic(HPEM) wave for protecting electronic devices as well as human resources. The topological analysis based on Baum-Liu-Tesche(BLT) equation simplifying the moving path of electromagnetic and the observation points and Power Balance Method(PWB) employing statistical electromagnetic analysis are introduced to analyze relatively electrically large cavity with little time consumption. In addition to the PWB method, full wave results for cylindrical cavity with apertures and incident plane wave are presented for comparison with time-consumption rate according to the cavity size.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.828-834
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• 2013

In this paper, TMC (Tracker Motion Controller) as one of the many research methods for condensing efficiency improvements can be condensed into efficient solar system configuration to improve the power generation efficiency of the castle with Concentrated solar silicon and photovoltaic systems (CPV)experiments using PV systems. Microprocessor used on the solar system, tracing the development of solar altitude and latitude of each is calculated in real time. Also accept the value from the sensor, motor control and communication with the central control system by calculating the value of the current position of the sun, there is a growing burden on the applicability. Through the way the program is appropriate for solar power systems and sensors hybrid-type algorithm was implemented in the ARM core with built-in TMC, Concentrated CPV system compared to the existing PV systems, through the implementation of the TMC in the country's power generation efficiency compared and analyzed. Sensor method using existing experimental results Concentrated solar power systems to communicate the value of GPS location tracking method hybrid solar horizons in the coordinate system of the sun's azimuth and elevation angles calculated by the program in the calculations of astronomy through experimental resultslook clear day at high solar irradiation were shown to have a large difference. Stopped after a certain period of time, the sun appears in the blind spot of the sensor, the sensor error that can occur from climate change, however, do not have a cloudy and clear day solar radiation sensor does not keep track of the position of the sun, rather than the sensor of excellence could be found. It is expected that research is constantly needed for the system with ongoing research for development of solar cell efficiency increases to reduce the production cost of power generation, high efficiency condensing type according to the change of climate with the optimal development of the ability TMC.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.6
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• pp.56-62
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• 2009

Inexpensive high performance computer systems combined with high speed networks and machine independent communication libraries have made cluster computing a viable option for parallel applications. In a heterogeneous cluster environment, efficient resource management is critically important since the computing power of the individual computer system is a significant performance factor when executing applications in parallel. This paper presents a dynamic task manager, called DWM (dynamic work manager). It makes a heterogeneous cluster system fully utilize the different computing power of its individual computer system. We measure the performance of DWM in a heterogeneous cluster environment with several kernel-level benchmark programs and their programming complexity quantitatively. From the experiments, we found that DWM provides competitive performance with a notable reduction in programming effort.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.2
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• pp.1-6
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• 2002

In this paper, an Analog Flat Panel interface(AFPI) which supports for UXGa(Ultar extended Graphics Array)-Compatible TFT LCD Driver is designed. The Proposed AFPI is composed of 8-b ADC, Automatic Gain Control(AGC), Low-Jitter PLL. In order to obtain a high speed and low power consumption, an efficient architecture of 8-bit ADC is proposed, whose FR(Folding Rate) is 8, NFB(Number of Folding Block) is 2, and IR (Interpolating Rate) is 16. We can get high SNDR by adopting distributed track and hold circuits. Also a programmable AGC which is possible to control gain and clamp, and a low-jitter PLL are proposed. The chip has been fabricated with 0.25${\mu}{\textrm}{m}$ 1-poly S-metal n-well CMOS technology. The effective chip area is 3.6mm $\times$ 3.2mm and it dissipates about 602㎽ at 2.5V power supply. The INL and DNL are within $\pm$ 1LSB. The measured SNDR is about 43㏈, when the input frequency is 10MHz at 200MHz clock frequency.

• Laser Solutions
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• v.7 no.2
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• pp.1-10
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• 2004

This work was attempted to join SCP sheet and STS304 sheet by using Nd:YAC laser beam. SCP sheet has good formability and low cost, while STS304 has excellent corrosion resistance and mechanical properties in high temp. In this experiment, butt joint type was used to develop the tailored blank welding for dissimilar steel. Sheets which have different thermal properties. Computer simulation was conducted to obtain the off-set position for efficient welding by considering laser power, scanning speed, focal length and basic properties. The result showed that the optimum thermal distribution was obtained when the laser beam was irradiated at $0.05{\sim}0.1$ mm off-set toward the SCP sheet side. The experiment was conducted based on the result of computer simulation to show the same optimum conditions. Optimum conditions were 3KW in laser beam power, 6m/min in scanning speed, -0.5mm in focal position, 0.1mm off-set toward SCP. Microhardness test, tensile test, bulge test, optical microscopy, EDS, and XRD were performed to observe the microstructure around fusion zone and to evaluate the mechanical properties of optimum conditions, The weld zone had high microhardness values by the formation of the martensitic structure. Tensile test measured the strength of welded region by vertical to strain direction and the elongation of welded region by parallel to strain direction. Bulge test showed $52\%$ formability of the original materials. Bead shape, grain size, and martensitic structure were observed by the optical microscopy in the weld zone. Detailed results of EDS, XRD confirmed that the welded region was connected of martensitic structure.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.72-77
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• 2011

The handling ability of containers at the terminal strongly depends on the performance of the cargo handling system such as RTGC(Rubber Tired Gantry Crane). This paper introduces a new guide line position measurement method using a camera for the RTGC which plays a important role in the harbor area. Because the line tracking is the basic technique for control system design of RTGC, it is necessary to develop a useful and reliable measurement system. If the displacement and angle of the RTGC relative to a guide line as trajectory to follow is obtained, the position of RTGC is calculated. Therefore, in this paper, a camera-based measurement system is introduced. The proposed measurement system is robust against light fluctuation and cracks of the guideline. This system consists of a camera and a PC which are installed at the lower side of the RTGC. Two edges of the guide line are detected from an input image taken by the camera, and these positions are determined in a Hough parameter space by using the Hough transformation method. From the experimental results, high accurate standard deviations were found as 0.98 pixel of the displacement and 0.24 degree of the angle, including robustness against lighting fluctuation and cracks of the guide line also.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.8-15
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• 2009

Although traditional single-hop cellular networks had been serving well in past years, they are no longer economically feasible in supporting high data-rate, multimedia services of $4^{th}$Generation (4G) communications due to the requirement of high transmission power By contrast, multi-hop cellular networks (MCN) are capable of dramatically saving the transmission power by overlaying the capability of ad hoc networking among mobile terminals on the cellular network infrastructure. To achieve this performance gain as well as enable 4G services, an efficient routing protocol needs to be designed for MCN. In this paper, we propose a reactive route discovery protocol for MCN that uses directional information to the base station in the route discovery process. Our analysis/simulation results have demonstrated that the proposed protocol significantly reduces flooding overheads. In addition, we consider issues for 4G services in MCN and applications of the proposed protocol.