• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.685-693
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• 2011

In the era of energy climate, IGCC technology is one of the powerful solutions for the demands of new energy with low carbon green growth. The present study is conducted to investigate the combustion characteristics of syngas from the coal gasifier to predict problems when it is fed to the gas turbine. Through high and low combustion tests, we understood that hydrogen is the main reason of NOx emission but easily controled by injecting the dilution of nitrogen. CO emission of syngas was comparable with that of methane and pressure fluctuation of syngas was not significant. The data from this study will be used for the optimization of combustion in the Korea first IGCC plant in 2015.

• Journal of KIISE:Software and Applications
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• v.35 no.5
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• pp.281-287
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• 2008

Data transfers occur during the execution time of a Java program, from constant to variable, from variable to other variable and so on. Data are located in memory and hence data transfer requires access to memory. As memory access generates both time delay and energy consumption it is absolutely necessary to know the data transfer overheads incurred among different paths not only to write an efficient program but also to build a high-performance Java virtual machine. In this paper we classify Java memory into three different regions, constant, local variable, and field, and then investigate data transfer overheads among these regions. The result says that the transfer between local variables incur the least overhead usually, while the transfer between fields incur the most. The difference of overheads reaches up to a double. Optimization techniques like JIT reduces the data transfer overhead dramatically. It is observed that the overhead is reduced from 14 to 27 times for the case of Hotspot JVM.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1E
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• pp.55-63
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• 1994

A decision-theretic concept is introduced to investigate whether targets of interest in array sensor systems are present at some steering direction or not. The solutions to this problem are described as a set of discrete numbers 0 or 1 corresponding to the direction under consideration. This coded number representation is transplanted in the optimisation technique based on the Hopfield neural network, which may provide an easy understanding of determining the direction of arrival (DOA) of sources. Difficulties encountered in using the conventional state schemes of Hopfield neural network models are addressed and their related issues are raised. To deal with them, an idea that a neuron that decreases more energy difference for its state change of 0 to 1can have higher priority in the order of state transition than others is introduced. This does not only lead to an new state update scheme but also opens a different story in comparison to previous work. To cast the perspectives of the proposed approach and illustrate its effectiveness in source direction finding in array sensor system. simulation results and related discussions are presented in this paper.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.211-216
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• 2017

This paper proposes image processing techniques that improve usability and performance in a diagnostic system of the contrast-enhanced ultrasonography. For a methodology for visualizing diagnostic parameter data in an ultrasonic medical image, an expression of transition time data with successive pixel values and a method of generating a lesion diagnostic parameter image with four categorized values are presented. We also introduce a MRF-based image enhancement technique to eliminate noises from generated parametric images. Such parametric image generation technique can overcome the difficulty of discriminating dynamic change in patterns in the ultrasonography. The technique clarifies the contour of the region in the original image and facilitates visual determination of the characteristics of the lesion through four colors. With regard to this MRF-based image enhancement, we define the energy function of consecutive pixel values and develop a technique to optimize it, and the usability of the proposed theory is examined through experiments with medical images.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.577-580
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• 2014

Indium hydroxy sulfide ($In(OH)_xS_y$) as a cadmium (Cd)-free buffer layer for $CuInGaSe_2$ (CIGS) solar cells was prepared by the chemical bath deposition (CBD) and the reaction time was optimized. The band gap energy and transmittance data alongside the thickness results from the direct observation with focused ion beam system (FIB) could be a powerful tool for optimizing the conditions. In addition, X-ray diffractometer (XRD), X-ray photoelectron microscopy (XPS), and scanning electron microscope (SEM) were also employed for the layer characterization. The results indicated that the optimum reaction time for $In(OH)_xS_y$ buffer layer deposition by CBD was 20 min at $70^{\circ}C$ under the conditions employed. At the optimum conditions, the buffer layer thickness was near 57 nm and the band gap energy was 2.7 eV. In addition, it was found that there was no XPS peak shift in between the buffer layers deposited on molybdenum (Mo)/glass and that on CIGS layer.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.111-119
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• 2010

Many researchers have studied on the optimal seismic design with the development of the computer. So far the application structure of most researches on the optimal seismic design was almost the moment resisting frame. Because the braced frames are the representative lateral load resisting system with the moment resisting frames, it is estimated that the effect on the practice will be great if it can is provided a design guideline through the development of optimal seismic design model for the braced frames. The purpose of this study is to propose the optimal seismic design model for the inverted V-type special concentrically braced frames considering the buckling of braces. The objective functions of this are to minimize the structural weight and maximize the total dissipated energy of the structure and the constraints of this are the strength conditions for the column, beam, brace and inter-story drifts condition. To verify the proposed model, it is applied to 2D steel concentrically braced frames of 3-story and 9-story.

• Convergence Security Journal
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• v.11 no.1
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• pp.11-18
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• 2011

Wireless mesh network technology with transmission speeds similar to wired and wireless technology means to build, compared with wired networks, building a more efficient network to provide convenience and flexibility. The wireless mesh network router nodes in the energy impact of the mobility is less constrained and has fewer features entail. However, the characteristics of various kinds due to network configuration settings and the choice of multiple paths that can occur when the system overhead and there are many details that must be considered. Therefore, according to the characteristics of these network routing technology that is reflected in the design and optimization of the network is worth noting. In this paper, a multi-path setting can be raised in order to respond effectively to the problem of the router node data loss and bandwidth according to traffic conditions and links to elements of the hop count evaluation by using a genetic algorithm as a workaround for dynamic routing the routing metric for wireless mesh network scheme is proposed.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.467-470
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• 2004

We have investigated the key parameters affecting ATP regeneration in a cell-free protein synthesis system derived from Escherichia coli. When glucose-6-phosphate was used as an energy source, the efficiency of ATP regeneration sharply responded to pH change of reaction mixture. In addition, both productivity and reproducibility of protein synthesis was substantially enhanced by introducing appropriate amount of NAD into the reaction mixture. As a result, through the activation of glycolytic pathway under an optimal pH, the batch cell-free system produced over $300\;{\mu}g$ of protein in a 1 mL reaction.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.179-186
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• 2011

Wireless Mesh Network technology refers to the technology which establishes wireless network whose transmission speed is similar to that of the wire system, and provides more enhanced flexibility in the building of network, compared to the existing wired network. In addition, it has the feature of less mobility and less restriction from the energy effect. However, there follow many considerations such as system overhead in the case of setting or the selection of multi-path. Accordingly, the focus is on the design and optimization of network which can reflect this network feature and the technology to establish path. This paper suggests the methods on the programming of path in Wireless Mesh Network routing by applying the evaluation value of node service, making use of the loss rate of data, the hop count of bandwidth and link and the traffic status of node, considering the performance of link and load in the fitness evaluation function, in order to respond to the programming of multi-path effectively.

• Journal of the Korean Institute of Gas
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• v.20 no.1
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• pp.52-61
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• 2016

Liquefied petroleum gas is regarded as a promising alternative fuel as it is eco-friendly, has good energy efficiency and output performance, practically and has high cost competitiveness over competing fuels. In spark-ignition engine, direct injection technology improves engine volumetric efficiency apparently and operates engine using the stratified charge that has relatively higher combustion efficiency. This study designed a combustion chamber equipped with visualization system by applying gasoline direct injection engine principle. In doing so, the study recorded and analyzed ignition probability and flame propagation process of spark-ignited direct injection LPG in a digital way. The result can contribute as a basic resource widespread for spark-ignited direct injection LPG engine design and optimization extensively.