• Journal of IKEEE
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• v.15 no.2
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• pp.179-189
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• 2011

This paper presents an SVC based multi-channel transmission technique. Transmission of high definition multimedia and its service efficiency can be significantly improved by the proposed method. In this method, the HD stream is divided into the two layer streams, i.e., a base layer stream and an enhancement layer stream. The divided streams are transmitted through a primary channel and an auxiliary channel, respectively. The proposed technique provides a noble mode switching technique which enables a seamless service of HD multimedia even under the conditions of abrupt and intermittent deterioration of the auxiliary channel. When the enhancement layer stream is disrupted by the channel monitoring in the mode switching algorithm, the algorithm works further to maintain the spatial and time resolution of the HD multimedia by upsampling and interpolating the base layer stream, consequently serving for the non disrupted play of the media. Moreover, the adoption of an adaptive switching algorithm significantly reduces the frequency of channel disruption avoiding the unnecessary switching for the short period variations of the channel. The feasibility of the proposed technique is verified through the simulation study with an example application to the simultaneous utilization of both Ku and Ka bands for HD multimedia broadcasting service. The rainfall modeling and the analysis of the satellite channel attenuation characteristics are performed to simulate the quality of service performance of the proposed HD broadcasting method. The simulation results obtained under a relatively poor channel (weather) situations show that the average lasting period of enhancement layer service is extended from 9.48[min] to 23.12[min] and the average switching frequency is reduced from 3.84[times/hour] to 1.68[times/hour]. It is verified in the satellite example that the proposed SVC based transmission technique best utilizes the Ka band channel for the service of HD broadcasting, although it is characterized by its inherent weather related poor reliability causing severe limitations in its independent application.

• Journal of The Korean Association For Science Education
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• v.36 no.3
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• pp.445-455
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• 2016

The purpose of this study is to identify the structural relationship among students' grit, interest, self-regulation ability, task-commitment and achievement within science learning. Our concern is understanding how grit is related to the other non-cognitive variables, i.e., interest, self-regulation ability, and task-commitment, which are widely known as significant predictors of science achievement. Based on literature review, we evaluated two hypothetical models in the frame of structural equation modeling as follows: first, grit was assumed to mediate relations of interest and self-regulation ability, and interest and task-commitment. Second, grit was assumed to have a direct effect on self-regulation ability and task-commitment independent of interest. In both models, grit was assumed to be indirectly associated with science achievement. A total number of 180 high school students (77 boys, 103 girls) participated in surveys on grit, interest, self-regulation ability, and task-commitment and reported their science test scores on mid-term/final exams. Results revealed that students' grit and interest were indirectly associated with their science achievement with the mediation of their self-regulation and task-commitment. We also found that task-commitment was highly correlated with interest and self-regulation. Furthermore, we found different patterns of correlations within the five variables between female and male students. From these results, we suggested that researchers need to investigate whether students' grit and task-commitment can explain their interest decreasing as they move to higher grade levels, how teachers can help students to maintain their interest in learning science from early childhood, and relationships of these non-cognitive variables and science achievement.

• 한국노년학
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• v.38 no.4
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• pp.1083-1105
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• 2018

The present study sought to capture day-to-day fluctuation of the daily happiness among Korean urban older adults and to examine whether the within person fluctuation of daily happiness is explained by the social and physical activities the older adults experience each day. We also examined whether the within person association between daily social, physical activities and the daily happiness varies by individual characteristics(i.e. gender, age, educational level and health). In addition, we explored the relationships between the level and fluctuation of daily happiness and the level of global happiness. The data was collected by multi-method approach, which includes general survey, daily diary method and collection of physical activity data through the activity monitors. In total, 175 urban older adults participated for seven days of daily diary survey. The data about the number of steps and the time spent on sedentary activities, light intensity physical activities and moderate to vigorous intensity physical activities were also collected during the same period from 16 sub-samples using activity monitors. Hierarchical linear modeling was applied for the analysis. The results were as below. First, the level of happiness of older adults fluctuated during a week, and the patterns of fluctuation varied by the gender and the health. Second, socializing with their children and friends elevated their levels of happiness. Also the impact of contacts with siblings on the level of daily happiness was greater for the unhealthy group compare to the healthy group. Third, older adults were happier on the days when they walked more, but the level of daily happiness decreased on the days when they spent longer time for low intensity physical activities. Lastly, the higher level of daily happiness were related to the higher level of global happiness, but the degree of fluctuation of daily happiness was not related to the level of global happiness. The implications of these results and suggestions for future research are discussed.

• Clean Technology
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• v.28 no.1
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• pp.79-93
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• 2022

In this study, an electronics industrial wastewater activated sludge model (e-ASM) to be used as a Water Digital Twin was calibrated based on real high-tech electronics industrial wastewater treatment measurements from lab-scale and pilot-scale reactors, and examined for its treatment performance, effluent quality prediction, and optimal process selection. For specialized modeling of a high-tech electronics industrial wastewater treatment system, the kinetic parameters of the e-ASM were identified by a sensitivity analysis and calibrated by the multiple response surface method (MRS). The calibrated e-ASM showed a high compatibility of more than 90% with the experimental data from the lab-scale and pilot-scale processes. Four electronics industrial wastewater treatment processes-MLE, A2/O, 4-stage MLE-MBR, and Bardenpo-MBR-were implemented with the proposed Water Digital Twin to compare their removal efficiencies according to various electronics industrial wastewater characteristics. Bardenpo-MBR stably removed more than 90% of the chemical oxygen demand (COD) and showed the highest nitrogen removal efficiency. Furthermore, a high concentration of 1,800 mg L^-1 T MAH influent could be 98% removed when the HRT of the Bardenpho-MBR process was more than 3 days. Hence, it is expected that the e-ASM in this study can be used as a Water Digital Twin platform with high compatibility in a variety of situations, including plant optimization, Water AI, and the selection of best available technology (BAT) for a sustainable high-tech electronics industry.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.931-939
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• 2022

In Korea, about two-thirds of the precipitation is concentrated in the summer season, so the problem of turbidity in the summer flood season varies from year to year. Concentrated rainfall due to abnormal rainfall and extreme weather is on the rise. The inflow of turbidity caused a sudden increase in turbidity in the water, causing a problem of turbidity in the dam reservoir. In particular, in Korea, where rivers and dam reservoirs are used for most of the annual average water consumption, if turbidity problems are prolonged, social and environmental problems such as agriculture, industry, and aquatic ecosystems in downstream areas will occur. In order to cope with such turbidity prediction, research on turbidity modeling is being actively conducted. Flow rate, water temperature, and SS data are required to model turbid water. To this end, the national measurement network measures turbidity by measuring SS in rivers and dam reservoirs, but there is a limitation in that the data resolution is low due to insufficient facilities. However, there is an unmeasured period depending on each dam and weather conditions. As a sensor for measuring turbidity, there are Optical Backscatter Sensor (OBS) and YSI, and a sensor for measuring SS uses equipment such as Laser In-Situ Scattering and Transmissometry (LISST). However, in the case of such a high-tech sensor, there is a limit due to the stability of the equipment. Therefore, there is an unmeasured period through analysis based on the acquired flow rate, water temperature, SS, and turbidity data, so it is necessary to develop a relational expression to calculate the SS used for the input data. In this study, the AEM3D model used in the Water Resources Corporation SURIAN system was used to improve the accuracy of prediction of turbidity through the turbidity-SS relationship developed based on the measurement data near the dam outlet.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.175-183
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• 2010

To understand the variation of macro benthos community according to the installation of structure and topographic placement in the shellfish farm on tidal flat, the practical example of the tidal shellfish growing area at Namsung-ri Goheung was observed. The results of the research for the field observation were summarized as follows. (1) The ground gradient of the shellfish farm was very flat below about $1^{\circ}$. The shellfish farm ground took the shape of $\sqcup$ from the shoreline to the place of 150 m seawards, and the shape of $\sqcap$ from there to the low tide line. During ebb tide, the $\sqcup$ shape ground stored the sea water, and the $\sqcap$ shape ground was supposed to act as the effect factor to leak slowly or to prevent the outflow. (2) The oyster shell bag or the type of riprap wall as the boundary in the shellfish farm was classified into five types. The air exposure time and flooding time were 181 and 434 minutes, respectively. (3) In the numerical experiment, the deep-sea water wave coming in the study area had 0.5 m of maximum wave height to show the very stable conditions and the wave direction pattern of S-direction was dominant at Naro great ridge, and SE, SSW and S-direction were distributed strongly around the shellfish farm. (4) By the grain size analysis, the sediment around tidal flat consisted of gravel 0.00~5.81(average 1.70)%, sand 14.15~18.39(average 13.23)%, silt 27.59~47.15(average 30.84)% and clay 35.79~55.73(average 36.19)%, and the sediment type was divided into (g)M(lightly gravelly mud), sM(sandy mud) and gM(gravelly mud) by Folk's diagram. (5) The macro benthos community survey conducted in this site in January, 2010 showed that 1 species of Mollusca, 8 species of Polychaeta and 2 species of Crustacea appeared, and 11 species occupying over 1% of total abundance were dominant.

• Journal of Korea Game Society
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• v.4 no.3
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• pp.11-20
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• 2004

Virtual reality that we have seen from the movies in 80's and 90's is hawing near based on the rapid progress of science together with a computer technology. Various virtual reality system developments (such as VRML, HMD FishTank, Wall Type, CAVE Type, and so on) and the advancement of those systems make for the embodiment of virtual reality that gives more sense of the real. Virtual reality is so immersive that makes people feel like they are in that environment and enable them to manipulate without experiencing the environment at first hand that is hard to experience in reality. Virtual reality can be applied to the spheres, such as education, high-level programming, remote control, surface exploration of the remote satellite, analysis of exploration data, scientific visualization, and so on. For some connote examples, there are training of a tank and an aeroplane operation, fumiture layout design, surgical operation practice, game, and so on. In these virtual reality systems, the actual operation of the human participant and virtual workspace are connected each other to the hardware that stimulates the five senses adequately to lend the sense of the immersion. There are still long way to go, however, before long it will be possible to have the same feeling in the virtual reality as human being can have by further study and effort. In this thesis, the basic definition, the general idea, and the kind of virtual reality were discussed. Especially, CAVE typed in reality that is highly immersive was analyzed in definition, and then the method of VR programming and modeling in the virtual reality system were suggested by showing the restoration process of Kyongbok Palace (as the content of the original form of the culture) that was made by KISTI(Korea Institute of Science and Technology Information) in 2003 through design process in virtual reality system. Through these processes, utilization of the immersive virtual reality system was discussed and how to take advantage of this CAVE typed virtual reality system at the moment was studied. In closing the problems that had been exposed in the process of the restoration of the cultural property were described and the utilization plan of the virtual reality system was suggested.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.172-193
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• 2013

This study examines the production techniques and raw materials shown in the Korean dried-lacquer statues of Buddha through a careful observation of the Seated Dried-lacquer Bodhisattva Statue from the late Goryeo Dynasty which is currently possessed by Okura Museum of Art in Tokyo. As a method of study, the X-ray data and the results from a field survey were combined to analyze the production techniques and the characteristics of raw materials. Based on this analysis, a hypothesis was established on the production process and verified through a reenactment of the actual production process. Then, the characteristics of the techniques applied to each process and the raw materials were recorded in detail. Specifically, the dried lacquer techniques and the raw materials were estimated based on the results of naked-eye observation in comparison with the literature, especially the records of "Xiu Shi Lu" written by Huang Cheng of the Ming Dynasty which is considered as 'the textbook of lacquer techniques.' The raw materials used in the production of the traditional Korean lacquerware inlaid with mother-of-pearl were also referenced. As a result, it was found that the features of production techniques and the raw materials found in the Statue at Okura Museum of Art have many similarities with those of the Seated Dried-lacquer Statue of Lohan (Arhat) from Yuanfu 2 Nian Ming (1098) of the Song Dynasty which is currently at the Honolulu Museum of Art. In particular, the similarities include that the interior of the statue being vacant because the clay and the wood core were not replaced after being removed from the prototype, that the complete form was made in the clay forming stage to apply the lacquer with baste fiber fabric, that the clay and the wood core were removed through the bottom of the statue, and that the modeling stage was omitted and the final coat over the statue is very thin. Additionally, decorating with ornaments like Bobal and Youngrak made of plastic material was a technique widely popular in the Song Dynasty, suggesting that the Seated Dried-lacquer Bodhisattva Statue in Okura Museum of Art was greatly affected by the production techniques of the Dried-lacquer Buddha Statue from the Song Dynasty. There is no precise record on the origin and history of the Korean Dried-lacquer Buddha Statues and the number of existing works is also very limited. Even the records in "Xuanhe Fengshi Gaoli Tujing" that tells us about the origin of the Dried-lacquer Buddha Statue from the Yuan Feng Period (1078~1085) do not indicate the time of transmission. It is also difficult to trace the clear route of transmission of production techniques through existing Dried-lacquer Buddha Statues. Fortunately, this study could at least reveal that the existing Dried-lacquer Buddha Statues of Korea, including the one at Okura Museum of Art, have applied the production techniques rather differently from those used in the production of Japanese Datsukatsu Dried-lacquer Buddha Statues that have been known as the standard rule in making dried-lacquer statues of Buddha for a long time.

• Journal of Korean Dental Hygiene Science
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• v.6 no.1
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• pp.37-50
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• 2023

Background: This study investigated the structural relationships among justice, test anxiety, and school reliability s non-face-to-face tests of dental hygiene students. Methods: A survey was conducted with 267 dental hygiene students. The survey items included general characteristics, opinions on evaluation, the fairness of non-face-to-face tests (distributive, procedural, and interactional justice), school satisfaction, and school reliability. For statistical analysis, independent-sample t-tests, one-way ANOVA, and structural modeling analyses were performed. Results: Among factors that directly affected distributive justice and reliability towards non-face-to-face tests, the higher the interactional justice (β=0.401, p<0.001) and distributive justice (β=0.232, p=0.002) levels, the higher the school satisfaction. The higher the school satisfaction (β=0.606, p<0.001) and procedural justice (β=0.299, p<0.001) levels, the higher the perceived reliability of the school. Factors that indirectly affected school reliability included interactional justice (β=0.243, p=0.010) and distributive justice (β=0.141, p=0.010). Interactional justice (β=0.592, p=0.010) and distributive justice (β=0.208, p=0.010) were the factors affecting school satisfaction. Moreover, factors that influenced school reliability were distributive justice (β=0.56, p=0.010), interactional justice (β=0.332, p=0.010), procedural justice (β=0.229, p=0.010), and distributive justice (β=0.116, p=0.010). Conclusions: Students will trust and be satisfied with schools when schools and professors sufficiently provide information on face-to-face tests and ensure proper procedures to achieve reasonable grades as rewards for exerted time and effort. Furthermore, this study provides a reference base for developing a variety of content for fair, non-face-to-face tests, thereby allowing students to trust their schools.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.400-412
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• 2023

In this study, the biogeochemistry management (BGC-MAN) model was applied to North and South Korea pine and oak forest stands to evaluate the Net Primary Productivity (NPP), an indicator of forest ecosystem productivity. For meteorological information, historical records and East Asian climate scenario data of Shared Socioeconomic Pathways (SSPs) were used. For vegetation information, pine (Pinus densiflora) and oak(Quercus spp.) forest stands were selected at the Gwangneung and Seolmacheon in South Korea and Sariwon, Sohung, Haeju, Jongju, and Wonsan, which are known to have tree nurseries in North Korea. Among the biophysical information, we used the elevation model for topographic data such as longitude, altitude, and slope direction, and the global soil database for soil data. For management factors, we considered the destruction of forests in North and South Korea due to the Korean War in 1950 and the subsequent reforestation process. The overall mean value of simulated NPP from 1991 to 2100 was 5.17 Mg C ha^-1, with a range of 3.30-8.19 Mg C ha^-1. In addition, increased variability in climate scenarios resulted in variations in forest productivity, with a notable decline in the growth of pine forests. The applicability of the BGC-MAN model to the Korean Peninsula was examined at a time when the ecosystem process-based models were becoming increasingly important due to climate change. In this study, the data on the effects of climate change disturbances on forest ecosystems that was analyzed was limited; therefore, future modeling methods should be improved to simulate more precise ecosystem changes across the Korean Peninsula through process-based models.