• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3800-3805
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• 2012

Infrared(IR) reflective black cool pigment and paint which is used for interior/exterior materials(IR reflectance >30%) to prevent heat island effect and to increase energy efficiency were studied. Cool pigment was synthesized using mixture of $Fe_2O_3$ and $Cr_2O_3$ with calcination from 900 to $1,200^{\circ}C$. Cool paint was prepared by formulation of cool pigment, acrylic resins, and other additives. Results showed that optimum color fixation of pigment obtained by mole ratio of Fe to Cr was 0.9 with calcination temperature at $1,000^{\circ}C$. The cool paint formulated by 20% pigment and 1.5% dispersive additive with $125{\mu}m$ thickness of coated layer showed optimum IR reflectance. Temperature difference on surface between cool paint and ordinary paint(STD) was $36.5^{\circ}C$ and IR reflectance(TSR) was 39.3% at wavelength from 700 to 2,500nm. And color change was not detected during 500hrs weathering test.

• Journal of KIISE
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• v.42 no.8
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• pp.1022-1030
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• 2015

The context-awareness of mobile applications yields several issues for testing, since mobile applications should be able to be tested in any environment and under any contextual input. In previous studies of testing for Android applications as an event-driven system, many researchers have focused on using generated test cases considering only Graphical User Interface (GUI) events. However, it is difficult to find failures that could be detected when considering the changes in the context in which applications run. It is even more important to consider various contexts since the mobile applications adapt and use the new features and sensors of mobile devices. In this paper, we provide a method of systematically generating various executing contexts from permissions. By referring to the lists of permissions, the resources used by the applications for running Android applications can be easily inferred. To evaluate the efficiency of our testing method, we applied the method on two open source projects and showed that it contributes to improve the statement code coverage.

• Proceedings of the KAIS Fall Conference
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• 2001.11a
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• pp.196-200
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• 2001

Foot has two functions : one is walking (or propulsion), the other is supporting or protecting of human body. In spite of such important roles, the importance of foot in keeping health has been easily disregarded. The bottom of foot is usually regarded as the second heart, for it is the pocket edition of all the principal parts of human body. Shoe is one of the tools to protect foot, and to wear a good shoe is the most demanded point in keeping health, Shoe can be different in kinds and shapes according to each one's usage. That is, different conditions of different people should have the different results in the material, design, last, pattern and structure in manufacturing shoe. A good shoe is absolutely a shoe with its right suitability, elasticity and adaptability. To make this healthy shoe, it is needed to design in the way of human technology, and the relative and scientific materials are basically required in manufacturing it. Recently there is an increasing demand for milti-functional shoe that can improve the efficiency of work in parallel with the maintenance of health. Accordingly this paper put its main purpose on the development of a healthy shoe based on proper and right theory and test.

• Journal of Surface Science and Engineering
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• v.40 no.4
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• pp.190-196
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• 2007

Dye sensitized solar cells(DSSC) are the most promising future energy resource due to their high energy efficiency, low production cost, and simple manufacturing process. But one problem in DSSC is short life time compared to silicon solar cells. This problem occurred from photocatalytic degradation of dye material by nanometer sized $TiO_2$ particles. To prevent dye degradation as well as to increase its life time, the transparent coating film is needed for UV blocking. In this study, we synthesized nanometer sized $TiO_2$ particles in sols by increasing its internal pressure up to 200 bar in autoclave at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several nm to 30 nm. Synthesized $TiO_2$ sols were coated on the backside of fluorine doped tin oxide(FTO) glass by ink jet printing method. With increasing coating thickness by repeated ink jet coating, the absorbance of UV region (under 400 nm) also increases reasonably. Decomposition test of titania powders dispersed in 0.1 mM amaranth solution covered with $TiO_2$ coating glass shows more stable dye properties under UV irradiation, compared to that with as-received FTO glass.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.974-985
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• 2017

Although the number of registered cars in South Korea is about 22million but, there is no national standard for automobile reference fuel in South Korea. Reference fuel is the fuel used for certificating vehicle performance, emissions and fuel economy. Now, domestic market fuels are used as reference fuel. However, the quality of domestic market fuel is constantly changing by seasonal and fuel manufacturers. It may effect vehicle performance, emissions and fuel efficiency test result. On this study, market diesel fuel quality was monitored and reference fuel standard(draft) was set by reflecting market fuel monitoring result. Reference fuel standard(draft) was applied to CRDI engine.

• Resources Recycling
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• v.26 no.5
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• pp.67-76
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• 2017

In order to efficiently recycle waste industrial nickel-cadmium batteries, anodic and cathodic materials were crushed by a cut mill and classified by sieves. We used wet magnetic separation method for eliminating iron components from the crushed powders. In addition, the acid leaching test for the obtained anode and cathode powders was carried out under various conditions by means of the wet process. At the optimum leaching conditions with 2.0 M $H_2SO_4$ at $90^{\circ}C$, 15 wt $H_2O_2$ and L/S=20 for 3 hours, the leaching efficiency of nickel and cadmium was 99%, respectively.

• Advances in environmental research
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• v.6 no.1
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• pp.1-14
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• 2017

New technologies or improvement of the existing technologies are required to enhance the efficiency of removal of pollutants from wastewater. In this study we attempted to produce and test the activated carbon produced from the refused tea waste for the removal of dyes from wastewater. The objectives of this investigation were to produce activated carbon from refused tea waste by chemical activation, evaluate its performance for the removal of color produced from Acid Yellow 36, and the modeling of its dye removal with the kinetic study. The activation was performed in two steps namely carbonization at $375{\pm}25^{\circ}C$ and chemical activation with HCl at $800^{\circ}C$ under the absence of Oxygen. Adsorption isotherms and kinetic studies were performed with a textile dye, Acid Yellow 36, at different concentrations (20-80 mg/L). The maximum dye removal (~90%) observed at 80 mg/L dye concentration and it reduced at low dye concentrations. Maximum adsorption (71.97 mg/g) was recorded at 96 h at $29{\pm}1^{\circ}C$. Low pH increased the dye adsorption (pH=2; 78.27 mg/g) while adsorption reduced at high pH levels indicating that the competition occurs in between OH- ions and AY36 molecules for the adsorption sites in RTAC. The Langmuir isotherm model clearly explained the dye adsorption, favorably, by RTAC. Moreover, kinetic studied performed showed that the pseudo second order kinetic model clearly describes the dye adsorption. Based on the results obtained in this study, it can be concluded that RTAC can be used for the removal of textile dyes.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.385-396
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• 2020

A uniaxial compression test was performed to analyse the mechanical properties and macroscale and mesoscale failure mechanisms of sandstone with pyrite concretions. The effect of the pyrite concretions on the evolution of macroscale cracks in the sandstone was further investigated through numerical simulations with Particle Flow Code in 2D (PFC2D). The results revealed that pyrite concretions substantially influence the mechanical properties and macroscale and mesoscale failure characteristics of sandstone. During the initial loading stage, significant stress concentrations occurred around the edges of the pyrite concretion accompanied by the preferential generation of cracks. Meanwhile, the events and cumulative energy counts of the acoustic emission (AE) signal increased rapidly because of friction sliding between the concretion and sandstone matrix. As the axial stress increased, the degree of the stress concentration remained relatively unchanged around the edges of the concretions. The cracks continued growing rapidly around the edges of the concretions and gradually expanded toward the centre of the sample. During this stage, the AE events and cumulative energy counts increased quite slowly. As the axial stress approached the peak strength of the sandstone, the cracks that developed around the edges of the concretion started to merge with cracks that propagated at the top-left and bottom-right corners of the sample. This crack evolution ultimately resulted in the shear failure of the sandstone sample around the edges of the pyrite concretions.

• Korean Medical Education Review
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• v.9 no.2
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• pp.1-12
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• 2007

Purpose: The aim of this study is to identify the elements of success in curriculum reformation using focus group interview and faculty survey. Methods: We analyzed the 105 questionnaires that were collected horn 450 faculties in Yonsei University College of Medicine from September 1 to September 12, 2005. The interview of focus group was conducted to 105 faculty and students using 10 interview questions from July 25 to August 29, 2005. The data of focus group interview and faculty survey were analyzed by content analysis. frequency and percentile. Results : 66.7% of faculty have pointed out that it is right a direction of new curriculum but there are some problems in curriculum management. The most frequently addressed problem in the new curriculum is as follows : ability of self-directed learning(15.3%). deficiency of faculty understanding(10.5%). The faculty comments on the improvement areas of new curriculum such as curriculum revision (8.6%). efficiency of curriculum management (6.7%), reward and incentive system of education(6.7%). The focus groups pointed out the important factors of curriculum reformation such as horizontal and vertical integrity between subjects, improvement of student achievement test, enhancement of self-directed learning. responsibility and authorities of course director. Conclusions : It should be concluded. to succeed curriculum reformation, which the purpose of curriculum reformation announces obviously and management group should effort continuously so that professors may understand the new curriculum. The course directors have to responsibility and authorities operating the subjects and the university should develop the students' evaluation system and faculty performance appraisal system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.296-302
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• 2019

In this study, a basic durability assessment was performed by selecting the main part of a trial product of a shale shaker, which is one of components for a mud circular system. For a preliminary durability assessment, it was assumed that the lifetime of the bearing for the vibrator motor and the stiffness of the support spring are affected by the vibration when the motor operates continuously. In the case of the motor, the initial p-p level was 0.72 g, but after 100 hours of operation, the p-p level was rapidly increased to 1.26 g. Bearing defects could be estimated through ball defect frequency analysis. In the case of the spring, the stiffness of the spring was reduced by approximately 3.78% at the end of 2,000 hours of the fatigue-durability test by applying excitation conditions to shale shaker body. In the future, we will analyze the influence of the particle removal efficiency of the shale shaker.