• Applied Chemistry for Engineering
• /
• v.21 no.5
• /
• pp.509-513
• /
• 2010

Recently, an amount of waste electronic devices such as LED and trichromatic fluorescent lamp has increased with the development of electronic industry. Reportedly, rare earth metals such as yttrium and europium have been discovered in the waste electronic devices. In order to improve the selectivity of yttrium and europium, the effects of the following factors on recovery experiment have been considered : i) fatty acids with various alkyl chain lengths, ii) the concentration of extractant, and iii) pH. The results show that the extraction efficiencies decrease at the same pH with decreasing the concentration of extractant and so $pH_{0.5}$ (That value of pH in an aqueous phase at which the distribution ratio is unity at equilibrium: 50% of the solute is extracted (E = 0.5) only when the phase ratio is unity.) moves into higher pH. The highest selectivity of yttrium and europium was obtained with tetradecanoic acid as extractant. The extraction mechanism of yttrium and europium was varied with the change of concentration of the tetradecanoic acid. $MR_3$single-species was formed from the yttrium and europium ion in the extractant concentration less than 0.1 M. On the other hand, the yttrium or europium ion is solvated with three molecules of tetradecanoic acid monomer like $MR_3{\cdot}$ 3RH in the extractant concentration more than 0.1 M.

• Journal of Internet of Things and Convergence
• /
• v.6 no.2
• /
• pp.65-72
• /
• 2020

The study aims to measure and analysis the spatial equity of Medical welfare facilities for older persons and services, and, based on this, to seek the plan to secure the fairness. To this end, the research was carried out by converging the studies of geography and regional development for the equity of social welfare studies and space arrangement on types and functions of Medical welfare facilities for older persons. The main results of the study showed that, first, in case of the spatial arrangement(desire-to-service), Medical welfare facilities for older persons are located in all areas of cities(Si) and counties(Gun) but mostly existing in cities. Second, in case of the equity of regional distribution of Medical welfare facilities for older persons, it can say the equity in Gun is higher than Si, comparing the regions of Si and Gun. Third, in case of spatial equity of sanatorium for older persons, the spatial equity of care facilities for older persons showed statistical difference depending on the time required to reach the facility, but no difference on distance. This study made various suggestions based on the results of the above research, and suggested the necessity of convergence studies grafting technologies such as AI and the Internet of Things.

• Korean Journal of Heritage: History & Science
• /
• v.55 no.2
• /
• pp.186-197
• /
• 2022

The Daejanggakgibi Stele of Silleuksa Temple in Yeoju is a stone stele from the Goryeo Dynasty that is inscribed with various stories about the construction of Daejanggak, a place where Buddhist scriptures were kept. This stele has been maintained for a long time in a state in which discoloration of the body has occurred, and the inscription has been partially damaged due to dozens of cracks. Using non-destructive analysis methods for stone artifacts, material investigation, portable X-ray fluorescence analysis, and ultrasonic velocity analysis for the stele were performed. It was confirmed that the stele body was composed of light gray crystalline limestone, and the base stone, support stone, and cover stone were medium-grained biotite granite. Portable X-ray fluorescence analysis confirmed that iron(Fe) was an original coloring element of the stele surface. From the distribution pattern of the coloration, it can be inferred that iron-containing materials flew down from between the stele body and the cover stone. Thereafter, living organisms or organic contaminants attached to it so that yellow and black contaminants were formed. Ultrasonic diagnosis revealed that the physical property of both the front and back surfaces ranged from fresh rocks(FR) to completely weathered rocks(CW), and the average weathering index was grade 3(intermediate). However, the point where cracks developed intensively was judged to be the completely weathered stage(CW), and some cracks located in the upper and lower parts of the stele bear potentially very high risk. It is necessary to monitor the movement of these cracks and establish reinforcement measures for conservation in the future.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.3
• /
• pp.361-367
• /
• 2024

Ultrasound in the air is widely used in industry as a measurement technique to prevent abnormalities in the machinery. Recently, the use of airborne ultrasound imaging techniques, which can find the location of abnormalities using an array transducers, is increasing. A beamforming method that uses the phase difference for each sensor is used to visualize the location of the ultrasonic sound source. We exploit a random sparse ultrasonic array and obtain beamforming power distribution on the source in a certain distance away from the array. Conventional beamforming methods inevitably have limited spatial resolution depending on the number of sensors used and the aperture size. A high-resolution ultrasound imaging technique was implemented by applying functional beamforming as a method to overcome the geometric constraints of the array. The functional beamforming method can be expressed as a generalized beam forming method mathematically, and has the advantage of being able to obtain high-resolution imaging by reducing main-lobe width and side lobes. As a result of observation through computer simulation, it was verified that the resolution of the ultrasonic source in the air was successfully increased by functional beamforming using the ultrasonic sparse array.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.4
• /
• pp.50-59
• /
• 2015

While the international construction industry for Korean companies have grown in market size exponentially in the recent years, the profit rate of small and medium sized construction companies (SMCCs) are incomparably lower than those of large construction companies. Furthermore, small and medium size companies, especially subcontractor, lacks the judgement of project involvement appropriateness, which leads to an unpredictable profit rate. Therefore, this research aims to create a profit rate prediction model for the international construction project focusing on SMCCs. First, the factors that influence the profit rate and the area of profit zone are defined by using a total of 8,637 projects since the year 1965. Seconds, an extensive literature review is conducted to derive 10 influencing factors. Multiple regression analysis and corresponding judgement technique are used to derive the weight of each factor. Third, cased based reasoning (CBR) methodology is applied to develop the model for profit rate analysis in the project participation review stage. Using 120 validation data set, the developed model showed 11% (14 data sets) of error rate for type 1 and type 2 error. In utilizing the result, project decision makers are able to make decision based on authentic results instead of intuitive based decisions. The model additionally give guidance to the Korean subcontractors when advancing into the international construction based on the model result that shows the profit distribution and checks in advance for the quality of the project to secure a sound profit in each project.

• The Journal of the Korea Contents Association
• /
• v.13 no.5
• /
• pp.517-526
• /
• 2013

Lifelong education promotion business to be the first to promote lifelong education promotion accountable to the governor of the city, the Lifelong Education Act Amendment (2007.12) emphasis on the research area 6 Lifelong Education and Lifelong Education Institute is established if analyzes what Gyeongsangnam-do lifetime policy implications for the promotion of education and implications are derived(through AHP). The results were as follows: occupational skill enhancement education (0.335) as the priority section. The development of life education policy (0.238) is the primary work process that must be initiated for the Gyeongnam life education promotion policy appropriate for the region's situation. This was followed by the development and distribution of life education program (0.148), construction of a connective system between life education organizations within the province (0.139) Raised the need to promote lifelong Education strategies, five core strategic industry linkages through regional industrial policy to keep pace with the flow of business for the Advancement of Education for the development and activation of Gyeongsangnam-do in a lifetime.

• The Journal of the Korea Contents Association
• /
• v.11 no.2
• /
• pp.238-250
• /
• 2011

In 2006, the number of days of the screen quota (theatrical movie screening days of Korean produced films in a year required by the law) was reduced to 73 days from 146 days per year. Three years after the reduction of screen quota, this paper studies the impact of reduction of screen quota system on Korean produced films. Using Non-parametric statistics, Gini Index and Regression analysis, this study shows that the average number of Korean moviegoer of Korean films which was released last three years(2007-2009) after the cutback of screen quota in 2006 is reduced to 640,109.9123 from 1,107,217.82 for three years(2003-2005) before the cutback. And this is significant in statistics. while Hollywood film gets 76,168,518 more audiences than the total number of audience for 2003-2005, the total numbers of Korean films is cut to 218,917,590 (2007-2009) from 245,802,356 (2003-2005). Gini Index of 2009(0.84) indicates that the inequality of a distribution of box office performance of Korean films is getting worse after the cutback. For now, the reduction of screen quota has negative effects for Korean films. Only the technological advance, education of relates personnel, redesigning of the related infrastructure, market-driven movies, creative production, and the promotion of the independent films can reduced the negative effects.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.3
• /
• pp.27-34
• /
• 2017

Recently, the importance of the industrial warehouse floor has been increasing due to the development of the distribution and logistics industry. In this present study, an early-hardening polymer floor mortar which can compensate for the limitation of conventional cement based floor mortar regarding fluidity and long curing time was developed. In order to achieve the early-hardening of mortar characteristic ultra rapid hardening cement was used as binder. Four types of mixture proportions in accordance with the vinyl acetate ethylene(VAE) polymer contents with range from 10% to 20% and the other proto proportion without VAE polymer were designed. Mechanical experiments including the fluidity test, compressive strength test, bending test, bond test, and abrasion test were conducted for all mixture proportions. From the flow test result, it was possible to achieve the high flow with 250 mm by controlling the amount of superplasticizer. The incorporation of VAE polymer was found to affect the compressive strength reduction, however, the flexural strength was higher than that of the proto mixture, and it was evaluated to increase the compressive strength / flexural strength ratio. Moreover, at least 2.6 times higher bond strength and more than 4 times higher abrasion resistance were secured. From the mechanical experiments results, the optimum mixing ratio of the VAE polymer was determined to be 10%. As a result of application and monitoring, it shows that it has excellent resistance to cracking, discoloration, impact, and scratch as well as bond performance compared to the cement based floor mortar.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.4
• /
• pp.221-232
• /
• 2009

The geographical distribution of freeze risk determines the latitudinal and altitudinal limits and the maximum acreage suitable for fruit production. Any changes in its pattern can affect the policy for climate change adaptation in fruit industry. High-definition digital maps for such applications are not available yet due to uncertainty in the combined responses of temperature and dormancy depth under the future climate scenarios. We applied an empirical freeze risk index, which was derived from the combination of the dormancy depth and threshold temperature inducing freeze damage to dormant buds of 'Changhowon Hwangdo' peach trees, to the high-definition digital climate maps prepared for the current (1971-2000), the near future (2011-2040) and the far future (2071-2100) climate scenarios. According to the geospatial analysis at a landscape scale, both the safe and risky areas will be expanded in the future and some of the major peach cultivation areas may encounter difficulty in safe overwintering due to weakening cold tolerance resulting from insufficient chilling. Our test of this method for the two counties representing the major peach cultivation areas in South Korea demonstrated that the migration of risky areas could be detected at a sub-grid scale. The method presented in this study can contribute significantly to climate change adaptation planning in agriculture as a decision aids tool.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.9 no.11
• /
• pp.501-512
• /
• 2019

The purpose of this study is to explore the necessity and method of the development of modern digital image contents using the story of the literary work 'Guunmong'' by Kim Man-joong. Collective intelligence technique is one of the most recommended. Today, most cultural content development is achieved through the application of digital technology through collaboration of various people from the planning stage to the completion stage. Most prototypes of local cultural contents are developed based on the literary works of artists from the region or background of the region on the works. These local cultural resources can be developed into experiential tourism products and used for the development of local cultural industry. This study first examines the availability of collective intelligence method as a way to effectively develop local cultural contents, and proposes application of image-telling technique and using web-toon characters in digital image contents development. In order to prove the practical applicability of the proposed method, we present an example of cultural contents development of 'Guunmong'. Finally, we propose a new business model based on collective intelligence to develop a system of creation and distribution of the cultural contents through the continuous collaboration.