• Smart Structures and Systems
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• v.26 no.2
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• pp.253-262
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• 2020

In this paper, a new higher order shear deformation model is developed for static analysis of functionally graded beams with considering porosities that may possibly occur inside the functionally graded materials (FGMs) during their fabrication. The model account for higher-order variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. The present work aims to study the effect of the distribution forms of porosity on the bending of simply supported FG beam. Based on the present higher-order shear deformation model, the equations of motion are derived by the principle of virtual works. Navier type solution method was used to obtain displacement and stresses, and the numerical results are compared with those available in the literature. A comprehensive parametric study is carried out to assess the effects of volume fraction index, porosity fraction index, and geometry on the bending of imperfect FG beams. It can be concluded that the proposed model is simple and precise for the resolution of the behavior of flexural FGM beams while taking into account the shape of distribution of the porosity.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.117-130
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• 2012

Due to the development of network and device, it is called mobile age that boosts various distribution routes of multi-media content and it constructs a new digital content consumption trend. N-screen is one of the new-introduced examples in the digital age and broadcasting industry believes it as a crisis and challenge as well. It becomes a ubiquitous multi-media environment that people watch multi-media content everywhere and any time they want to and competition happens beyond the boundaries such as network industry, terminal industry, pay TV market, traditional terrestrial TV, etc. And then how should the broadcasting service prepare for the N-screen business? The present research proposes a few terrestial broadcasting content strategies in the multi platform environment. First, instead of N-screen, it proposes multi platform, especially One Source Multi Platform(OSMP). Second, so-called 'Integrated Terrestrial Broadcasting OSMP Alliance(IBPA)' must be founded. Third, IBPA should support multi-tasking UX for viewers to have rich experience. Last, it becomes more important and necessary to support local terrestrial broadcasting service for public service in the multi platform age.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.43-47
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• 2002

The new core making method economizing the amount of core sand has been requested. The new method is that a core box is heated until it reaches reasonable temperature and then core sand with core binder is sprayed into the core box. Since inner temperature distribution have to be uniform in order to form uniform thickness of core, we studied inner temperature distribution of core box. First, we determined proper number of torches and optimized torch positions to minimize the average of absolute deviation(AVEDEV) of inner temperature. The results are as fellowed: 1. The number of torches that enables uniform inner temperature distribution about $300^{\circ}C$ is 25. 2. When $S_H$ and $S_V$ is 0.7, the torch positions are optimized and AVEDEV is 5.85.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.567-575
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• 2001

A methodology is developed for designing the minimum-cost water distribution network. The method is based on network simulations and an optimization scheme using genetic algorithms. Being a stochastic optimization scheme, genetic algorithms have advantages over the conventional search algorithms in solving network problems known for their nonlinearities and herculean computational costs. While existing methods focus on the design of either entirely new or parallel augmentation of network systems, the proposed method can be applied to problems having both new branches of tree-type and paralle augmentation in loops. The applicability of the method was shown through a case study for Baekryeon water supply system. The optimized design resulted in the maximum 5.37% savings compared to the conventional design without optimization, while meeting the hydraulic constraints.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.6-9
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• 2001

This paper presents a new method which applies a genetic algorithm(GA) for determining which sectionalizing switch to operate in order to solve the distribution system loss minimization re-configuration problem. The distribution system loss minimization re-configuration problem is in essence a 0-1 planning problem which means that for typical system scales the number of combinations requiring searches becomes extremely large. In order to deal with this problem, a new approach which applies a GA was presented. Briefly, GA are a type of random number search method, however, they incorporate a multi-point search feature. Further, every point is not is not separately and respectively renewed, therefore, if parallel processing is applied, we can expect a fast solution algorithm to result.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.223-230
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• 1995

The phannacokinetics and tissue distribution of DWQ-013, a new quinolone, were examined in rats and mice following a single intravenous and oral administration. DWQ-013 in plasma and urine was determined by both HPLC and microbiological assay. The plasma concentration of the drug declined biexponentially. The terminal half life of the drug was 11.11$\pm$0.14 hour after intravenous dosing. The volume of distribution at terminal elimination phase(Vd$_\beta$) and total clearance of the drug were 1.29$\pm$0.15 l/kg and 0.78$\pm$0.09 l/h/kg. The bioavailability of DWQ-013 after oral administration was 56.0% (HPLC) and 77.2%(bioassay), respectively. Twelve-hour urinary recovery of drug was measured by HPLC and bioassay to 0.035$\pm$0009% and 4.71$\pm$066% after oral dosing, to 0.055$\pm$0.014% and 7.65$\pm$1.53% after intravenous dosing, which may indicate the presence of biologically active metabolites. Binding of the drug to plasma proteins ranged from 97%~99% at various concentrations. The drug was highly distributed in order of liver, kidney and lung after 1.5 hours in mice.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.202-208
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• 2015

In this study, we propose a new inference algorithm for a multiclass Gaussian process classification model using a variational EM framework and the Laplace approximation (LA) technique. This is performed in two steps, called expectation and maximization. First, in the expectation step (E-step), using Bayes' theorem and the LA technique, we derive the approximate posterior distribution of the latent function, indicating the possibility that each observation belongs to a certain class in the Gaussian process classification model. In the maximization step, we compute the maximum likelihood estimators for hyper-parameters of a covariance matrix necessary to define the prior distribution of the latent function by using the posterior distribution derived in the E-step. These steps iteratively repeat until a convergence condition is satisfied. Moreover, we conducted the experiments by using synthetic data and Iris data in order to verify the performance of the proposed algorithm. Experimental results reveal that the proposed algorithm shows good performance on these datasets.

• Journal of Digital Contents Society
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• v.16 no.5
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• pp.795-803
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• 2015

is a service providing story synopsis that matches user's query. This paper analyzes the user log of and shows the tendency distribution of user creation in comparison to stories in database. We also investigate the log to see possible improvements on search method. This paper proposes a concept of Story Map, in which the query-answer information is projected into spatial coordinates, and a new story search UI based on it. Using the Story Map, users are able to see entire spatial distribution of story database so that they can quickly and intuitively find a story on the map.

• Journal of the Korean Solar Energy Society
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• v.32 no.1
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• pp.32-39
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• 2012

New and renewable energy systems(solar thermal system, photovoltaic system, geothermal system, wind power system) are environmentally friendly technologies and these in South Korea are very important measures to reduce greenhouse-gas(GHG) and to push ahead with Green Growth. The purpose of this paper is to analyze GHG mitigation potential by distribution of solar thermal system in housing sector with bottom-up model called 'Long-range Energy Alternative Planning system'. Business as usual(BAU) was based on energy consumption characteristic with the trend of social-economic prospects and the volume of housing. The total amount of GHG emission of BAU was expected to continuous increase from 66.0 million-ton $CO_{2e}$ in 2007 to 73.1 million-ton $CO_{2e}$ in 2030 because of the increase of energy consumption in housing. The alternative scenario, distribution of solar thermal system in housing sector had GHG mitigation potential 1.54 million-ton $CO_{2e}$ in 2030. The results of this study showed that new and renewable energy systems made a contribution of reducing the use of fossil fuel and the emission of greenhouse-gas in building.

• Journal of Hydrogen and New Energy
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• v.27 no.1
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• pp.106-113
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• 2016

Lean burn engine, classified into port injection and direct injection, is recognized as a promising way to meet better fuel economy. Especially, LPG direct injection engine is becoming increasingly popular due to their potential for improved fuel economy and emissions. Also, LPDi engine has the advantages of higher power output, higher thermal efficiency, higher EGR tolerance due to the operation characteristics of increased volumetric efficiency, compression ratio and ultra-lean combustion scheme. However, LPDi engine has many difficulties to be solved, such as complexity of injection control mode (fuel injection timing, injection rate), fuel injection pressure, spark timing, unburned hydrocarbon and restricted power. This study is investigated to the influence of spark timing, fuel injection position and fuel injection rate on the combustion stability of LPDi engine. Piston shape is constituted the bowl type piston. The characteristics of combustion is analyzed with the variations of spark timing, fuel injection position and fuel injection rate (early injection, late injection) in a LPDi engine.