• Journal of Science Education
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• v.40 no.1
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• pp.17-30
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• 2016

The purpose of this study was to investigate the effects of problem solving activities of STEAM program on metacognition of middle school students. The subject was 63 middle school students. This study was designed single group pre-posttest. A single-group t-test was performed for analyzing difference between the pre-post test on metacognition. In the result of this study, there was significant difference between pretest and posttest on middle school students' metacognition. Also there was significant difference on metacognitive knowledge and metacognitive regulation. The analysis on the subelements of metacognition showed significant difference between pretest and posttest. The multiple regression analysis to investigate the relation of sub-elements of metacognition was performed in this study. The result of the analysis showed high explanatory power among metacognition subelements. This result suggests that the problem solving activities of STEAM program can have a positive effect in promoting metacognition. of the learner.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.153-159
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• 2004

The purpose of this research is to investigate the performance of swirl combustion chamber diesel engine by changing the jet passage area, the depth and shape of the piston top cavity (main chamber). The performance of diesel engine with newly changed swirl combustion chamber was tested through the experimental conditions as engine speed, load and injection timing etc. The test results were compared and analyzed. And another purpose of this research is to make a new diesel engine that is satisfied fuel consumption and regulation value of exhaust gas. 1. The rate of fuel consumption was affected significantly by the jet passage area at the high speed and load than low speed and low load. The influence of jet passage large area was proven to decrease the rate of fuel consumption. 2. Smoke was affected significantly by the depth of the piston top cavity, but exhaust temperature and the rate of fuel consumption wasn't affected. The rate of fuel consumption was affected by changing injection timing. 3. The rate of fuel consumption, exhaust temperature and Smoke were affected significantly by the shape of the piston top cavity from rectangular to trapezoid. That is we have all high value. The exhaust smoke density and exhaust gas temperature depended sensitively on variation of the injection timing rather than the shape of the combustion chamber within the experimental conditions. 4. We made a new diesel engine that is satisfied design target values(sfc=190 g/hr, NOx + THC=6.0 g/KWh, PM=0.3 KWh), the rate of fuel consumption and emission standard etc., through changing injection timing at the maximum torque point and rated power point. Although we have a little high NOx value.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.113-121
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• 2017

As the industrial structure of the mobile telecommunications market is transforming into the ICT ecosystem centered on smartphones, the regulatory system conforming to the new ICT environment has become the main subject of discussion in key developed countries. The EU segmented the mobile phone service into wholesale and retail. Simultaneously, the EU appraised mobile telecommunication carriers' market domination in segmented markets to continuously improve the scheme to promote competition in the telecommunications market. In Korea, also, there is discussion about adopting the EU scheme to segment the mobile phone market definition more finely and taking measures to appraise the market domination in accordance with object appraisal criteria. As such, this study analyzes whether the current criteria for appraising the wholesale termination rate market domination under the ICT's domestic mobile telecommunication ecosystem is adequate and presents the rational improvement measures reflecting the theoretically suggested evaluation factors.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.68-75
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• 2011

A vehicle fuel economy is very important issue in view of fuel cost and environmental regulation. It has been improved according to the performance improvement of the vehicle engine, power train and many components. It was evaluated at given mode (LA-4, FTP-75, etc) on an engine dynamometer or computer simulation program. In this paper, the fuel economy improvement cruise control algorithms as controling a vehicle velocity by road load calculated and predicted in a real expressway with gradient was studied. Firstly, the altitude and distance data which was measured with GPS sensor was already installed in the ECU of a vehicle. Then the vehicle equipped with GPS receiver is driven the same expressway. The ECU calculates the gradient angle and the in-/decreasing velocity using the gradient angle by comparing the current received distance and altitude data from GPS with the saved data ahead of the vehicle. Therefore the ECU can calculate and predict the vehicle velocity considering tolerance velocity of next position with running. Then the ECU controls the vehicle velocity to meet this predicted velocity in all section. Three cruise control algorithms with the different velocity profiles for the improvement of fuel economy are proposed and compared with the computer simulation results that the vehicle runs on Youngdong expressway. The proposed CVELCONT2 and CVELCONT3 algorithms were improved 3.7% and 4.8% of fuel economy compared with CONSTVEL which is steady cruising algorithm. These two algorithms are recommended as the Eco-cruise drive methodologies in this paper.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.457-463
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• 2005

KHNP(Korea Hydro and Nuclear Power Ltd., Co.) is developing a HIC transport package which is satisfying domestic and IAEA regulations and NETEC(Nuclear Environment Technology Institute) is conducting a conceptual design. In this study, the shielding thickness was calculated using the data from radionuclide assay program which is currently using in nuclear sites and Micro Shield code. Considering the structural safety, carbon steel was chosen as shielding material and the shielding thickness was calculated for 500 R/hr and 100 R/hr at HIC surface, respectively. Through the shielding analysis, it was evaluated that the regulation limit is satisfied when the shielding thickness is 22 cm for 500 R/hr and 17 cm for 100/hr.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.134-142
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• 2003

Most of the vibration and noise generating in small boats come from shipboard machinery such as main engine, generator and auxiliary machinery etc. In order to build up the comfortable environment for the crew and to reduce the ambient noise, and provide basic materials for reasoning selection application, the design under allowable vibration & noise conditions and the examination of vibration condition of the new ships, this paper researches the frequency spectrum and order analysis of vibration and noise. The obtained results are summarized as follows : Through comparing the small boat internal noise with the regulation of IMO and DNV, it revealed that the noise level of main engine room accords with the standard, and the noise of other places are beyond the values. In this paper, two boats are analyzed, which are same type, same size and power, but the main engines noise of them is different. In order to search the noise source, the noise of main engine room and relative parts are measured. The third order of measured points is dominant in frequency domain by the order analysis.

• Journal of Environmental Impact Assessment
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• v.23 no.4
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• pp.237-250
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• 2014

A wide range of projects for ocean renewable energy are currently in development around the world and ocean energy industries continue to receive significant support from their governments. Surrounded by sea on three sides, Korea has potentially abundant renewable ocean energy resources, which include tidal current, tidal range, offshore wind power, osmotic pressure and ocean thermal energy. Numerous ocean renewable energy projects has been developed in Korea. Nevertheless, there are some concerns that those developments often select an environmentally unsuitable location and/or there are very few existing information on those environmental effects. The purpose of this study is to improve supporting policies and regulation systems of ocean renewable energy development in Korea by reviewing and compiling government policies and environmental assessment systems related to ocean renewable energy development around the world. The study suggests several policy implications for its environmental-friendly development in Korea, including requirements of strategic environmental assessment for proactive and environmentally suitable site selection of ocean renewable energy development and continuous post-development environmental monitoring, and so on.

• Journal of the Korea Safety Management & Science
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• v.18 no.3
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• pp.63-70
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• 2016

The main point of this study is to find out duplicates and differences among various regulations from different organizations. Also, it focuses on creating a reasonably unified regulation system to standardize safety & environment management. In this study, I analyzed the commonalities and the differences of two systems which are typical korean Process Safety Management System and off-site Consequence Analysis. It is confirmed that there are 25 species of overlapped material of those two systems and assessment like handling material information, facilities lists, hazardous substances and list of machine power. Process safety report focuses on onsite workers and facility protect. On the other hand, off-site Consequence Analysis focuses on design, arrangement and management of handling facility from off-site influence. I found difference two system of Enforcement purposes and way. Contradiction of Harmful information of Chemicals Control Act and occupation safety and health acts from same material. To be specific, There are no unit rule of occupation safety and health acts. so it permit inch, psi etc. But Chemicals Control Act provides that m, Mpa units. Therefore, Each regulatory duplication of items for chemicals management, standardization is writing so that you can coordinate overlapping items in the measures the need to be presented.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.460-463
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• 1997

One of the major problems in automation of soybean sprouter is watering method. This study was conducted solve this problem. The soybean sprouter consisted of three parts: water-receiving chamber with siphon, water spraying bowl and sprout cultivating bowl. It functions as automatic-watering without manpower and electric power, and is not noisy and has duration. Watering interval, watering time and amount could be controlled by regulation of dropping times/min from a tap. Chlorine contained in tap water is naturally decreased during its (water) storage in the water receiving chamber. Among three types of sprouter (siphon type, wet paper type and water pump type) the siphon type can be used at $25{\sim}30^{\circ}C$ that is the optimum temperature for soybean sprout.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.23-30
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• 2011

This paper presents a Single-Inductor Multiple-Output (SIMO) DC-DC Converter with a negative feedback selection circuit to improve a regulation property at light load and to generate independent multiple outputs. The conventional SIMO DC-DC converter with a fixed negative feedback circuit cannot regulate correctly at light load. The SIMO DC-DC converter with the proposed negative feedback selection circuit has been designed in 0.35um 2-poly 3-metal BCDMOS. This converter is dual output boost converter with the 1.5V input and 2.5V, 3.0V output. The power conversion efficiency varies from 59% at 10mA loads to 85% at 50mA loads.