• Journal of Korea Technology Innovation Society
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• v.16 no.3
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• pp.582-604
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• 2013

The machinery industry provides infrastructure to many manufacturing industries and it has strong influences on performance and quality of products. However, Korean economic growth has been constantly causing the korean general machinery industry to significantly depend on Japan. To solve this problem, many industrial policies have been tried. In this paper, we divide the value chain of general machinery industry into four steps; technology development step, manufacturing step, marketing step, and after-sales management step. We study the relationships between each of these steps and the awareness of dependency on Japan. For empirical analysis we surveyed 207 domestic companies in general machinery industry. The findings are that the three factors, technology development competency, marketing competency and after-sales management competency have significant relationships with dependence on Japan. Manufacturing competency is not a significant factor. As control variables, the type of manufacturers has effect on dependency on Japan. The company size, the kinds of products and technology levels of products don't have effects on the relationship between the four steps of the value chain and dependency on Japan. To overcome the trade imbalance with Japan in the general machinery industry, we recommend to develop technology development competency, marketing competency, and after-sale management competency. Also we need to adopt industry supporting policies, not depending on all three control variables of company sizes, the kinds of products and the technology levels of products, but depending on the type of manufacturers.

• Membrane Journal
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• v.28 no.2
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• pp.121-128
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• 2018

Terpolymers, which are chemical compounds composed of three different chemical compounds, have rarely been utilized for gas separation membranes. In this study, we demonstrate a simple process to fabricate a composite membrane for $CO_2/N_2$ separation based on a terpolymer synthesized from poly(2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] ethylmethacrylate)(PBEM), poly(oxyethylene methacrylate)(POEM), and methyl methacrylate (MMA) via free radical polymerization. A solution of the as-synthesized PBEM-PMMA-POEM was coated onto a microporous polysulfone (PSf) support to form a composite membrane. The successful polymerization and the characteristics and morphology of the membrane were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM). The gas permeance and $CO_2/N_2$ selectivity of the PBEM-PMMA-POEM terpolymer membrane were measured at $25^{\circ}C$. A maximum $CO_2/N_2$ selectivity of 30.2 was obtained at a $CO_2$ permeance of 57.4 GPU ($1GPU=10^{-6}cm^3$(STP)/($s\;cm^2\;cmHg$)).

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.4
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• pp.335-344
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• 2014

The Quality of municipal solid waste incineration ash (incineration ash) was analyzed for the purpose of the reusing for concrete material. The folwability and strength properties of concrete mixed with incinerator ash were investigated. CaO component was included more than 50% in chemical component of incinerator ash, mean size of 50% accumulated particle distribution of incinerator ash was about $25{\mu}m$. Particle shape of incinerator ash ($IA_1$) was massed the round shape with fine particle, particle shape of incinerator ash ($IA_2$) was piled up the sheet shape according to manufacture procedure. The Quality of concrete was effected by use of incinerator ash. When the incinerator Ash ($IA_2$) was used, slum of concrete was increased and dosage of high range water reducing agent was reduced. However, strength development of concrete was decreased. Dosage of high range water reducing agent was increased by combined use of incinerator ash ($IA_2$) and diatomite powder, but strength development of concrete was improved. Ratio of compressive strength and tensile strength was in the range 85%~105% of CEB-FIP model code.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.779-789
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• 2014

Cognitive radio (CR) technology based on geo-location database access approach and/or wideband spectrum sensing approach is absolutely vital in order to recognize available frequency bands in white spaces (WSs), and efficiently utilize shared spectrums. This paper presents a new structure for the TVWS database access protocol implementation based on Internet Engineering Task Force (IETF) Protocol to Access WS database (PAWS). A wideband compressive spectrum sensing (WCSS) scheme using a modulated wideband converter is also proposed for the TVWS utilization. The developed database access protocol technology which is adopted in both the TV band device (TVBD) and the TVWS database operates well in the TV frequency bands. The proposed WCSS shows a stable performance in false alarm probability irrespective of noise variance estimation error as well as provides signal detection probabilities greater than 95%. This paper also investigates Federal Communications Commision (FCC) regulatory requirements of TVWS database as well as European Telecommunications Standards Institute (ETSI) policy related to TVWS database. A standardized protocol to achieve interoperability among multiple TVBDs and TVWS databases, which is currently prepared in the IETF, is discussed.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.1
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• pp.61-70
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• 2005

In order to reduce salt(as NaCl) contents in food waste and to improve the quality of discharged wastewater produced during the recycling process of food waste for the purpose of compost and feed stuff, a salt reduction process by added water into food waste was developed. The pilot plant with a rotary type salt reduction equipment to manage continuously 0.5 ton food waste per hour was constructed and the efficiency was tested. The amount of added water was calculated by the water content and the efficiency of dewatering process of food waste. Approximately 0.8 liter water per a kilogram of food waste was injected into the reactor in which food waste was pouring simultaneously, then diluted/mixed in a rotary reactor. About 1.1 liter of leachate including added water was generated, but the leachate contained a very high content of organic particles, so most particles were recovered by two step solid-liquid separation process. The first step was a gravitational filtering process using screens with a pore diameter of 1mm, and the second separation process was centrifugal process. Organic quality of food waste which had been desalted was maintained by inputting the entirely recovered organic particles. The efficiency of salt reduction of food waste was estimated by measuring a chloride anion by titration and salinity by a probe. The results by the two different measuring methods were always over 50%, and the quality of final wastewater was improved up to $200mg/{\ell}$ as TS(total solid) by an additional settling process after the two step solid-liquid separation process.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.50-58
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• 2017

Recently, some methods of converging heterogeneous fire sensor data have been proposed for effective fire detection, but the rule-based methods have low adaptability and accuracy, and the fuzzy inference methods suffer from detection speed and accuracy by lack of consideration for images. In addition, a few image-based deep learning methods were researched, but it was too difficult to rapidly recognize the fire event in absence of cameras or out of scope of a camera in practical situations. In this paper, we propose a novel fire detection system combining a deep learning algorithm based on CNN and fuzzy inference engine based on heterogeneous fire sensor data including temperature, humidity, gas, and smoke density. we show it is possible for the proposed system to rapidly detect fire by utilizing images and to decide fire in a reliable way by utilizing multi-sensor data. Also, we apply distributed computing architecture to fire detection algorithm in order to avoid concentration of computing power on a server and to enhance scalability as a result. Finally, we prove the performance of the system through two experiments by means of NIST's fire dynamics simulator in both cases of an explosively spreading fire and a gradually growing fire.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.655-663
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• 2016

Increasing green house gas and it consequent climate change problems are discussed as a global issue. Accordingly, future local green house gas emission will increase up to 40% of the entire local green house gas emission and therefore, efforts to reduce the emission in construction industry is urgently required. Therefore, in this study, heating energy demand was analyzed by using the EnergyPlus simulation according to wood material finishes configuration. EnergyPlus has the entry for a variety of buildings and heating, ventilation, air conditioning (HAVC) system components, in particular buildings, air conditioning systems, and performs simultaneous integrated calculated through the feedback between the heat source unit, a verification program according to the ASHRAE Standard 140-2007 to be. The climate data for the simulation we used the data IWEC in Incheon and Gwangju provided by EnergyPlus. The analysis of simulation model was farm and fishing house standard design drawings: 2012, presented at the Korea Rural Community Corporation. The results of simulation of central region and southern region were effected by wood products of simulation model into the interior finish, exterior finish, windows, wooden structure. Also, it was confirmed that the reduced heating energy demand.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.529-539
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• 2004

The corrosion of steel rebars has been the major cause of reinforced concrete deterioration. FRP(Fiber-reinforced polymer) rebar has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. However, FRP rebar is prone to deteriorate due to other degradation mechanisms than those for steel. The high alkalinity of concrete, for instance, is a possible degradation source. Therefore, the USA, Japan, Canada, UK. etc are using environmental reduction factor. Although difference design guidelines were drawn in many, including USA, Japan, Canada, UK etc, recommendations and coefficients that could take into account the long-term behavior of FRP reinforcement were not well defined. This study focuses on recommendation of environmental reduction factor of FRP rebar. Environment reduction factor were decided using durability test result. FRP rebars were subjected to twelve type of exposure conditions including alkaline solution, acid solution, salt solution and deionized water etc. The water absorption behavior was observed by means of simple gravimetric measurements and durability properties were investigated by performing tensile, compressive and short beam tests. Based on the experimental result, environmental reduction factor of hybrid FRP rebar(A), and (C) and CFRP rebar was decided as 0.85. Also, hybrid FRP rebar(B) and GFRP rebar were decided as 0.7 for the environmental reduction factor

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.655-663
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• 2010

Wettability is important to enhance not only CHF but also nucleate boiling heat transfer, as shown by the results of different kinds of boiling experiments. In this regard, an excellent boiling performance (a high CHF and heat transfer performance) could be achieved in the case of pool boiling by some favorable surface modifications that can satisfy the optimized wettability condition. To determine the optimized boiling condition, we design special heaters to examine how two materials, which have different wettabilities (e.g., hydrophilic and hydrophobic materials), affect the boiling phenomena. The special heaters have hydrophobic dots on a hydrophilic surface. The contact angle of the hydrophobic surface is $120^{\circ}$ to water at the room temperature. The contact angle of the hydrophilic surface is $60^{\circ}$ at same conditions. Experiments involving micro hydrophobic dots and two types of milli hydrophobic dots are performed, and the results are compared with a reference surface.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.7
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• pp.619-628
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• 2000

Abstract Perspective views provide a powerful depth cue and thus aid the interpretation of complicated images. The main drawback of current perspective volume rendering is the long execution time. In this paper, we present an efficient perspective volume rendering algorithm based on coherency between rays. Two sets of templates are built for the rays cast from horizontal and vertical scanlines in the intermediate image which is parallel to one of volume faces. Each sample along a ray is calculated by interpolating neighboring voxels with the pre-computed weights in the templates. We also solve the problem of uneven sampling rate due to perspective ray divergence by building more templates for the regions far away from a viewpoint. Since our algorithm operates in object-order, it can avoid redundant access to each voxel and exploit spatial data coherency by using run-length encoded volume. Experimental results show that the use of templates and the object-order processing with run-length encoded volume provide speedups, compared to the other approaches. Additionally, the image quality of our algorithm improves by solving uneven sampling rate due to perspective ray di vergence.