• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.97-105
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• 2010

A quantitative single particle analytical technique, denoted low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), was applied to characterize particulate matters collected at two underground subway stations, Jegidong and Yangje stations, in Seoul, Korea. To clearly identify the source of the indoor aerosols in the subway stations, four sets of samples were collected at four different locations within the subway stations: in the tunnel; at the platform; near the ticket office; nearby outdoors. Aerosol samples collected on stages 2 and 3 ($D_p$: $10-2.5\;{\mu}m$ and $2.5-1.0\;{\mu}m$, respectively) in a 3-stage Dekati $PM_{10}$ impactor were investigated. Samples were collected during summertime in 2009. The major chemical species observed in the subway particle samples were Fe-containing, carbonaceous, and soil-derived particles, and secondary aerosols such as nitrates and sulfates. Among them, Fe-containing particles were the most popular. The tunnel samples contained 85-88% of Fe-containing particles, with the abundance of Fe-containing particles decreasing as the distances of sampling locations from the tunnel increased. The Fe-containing subway particles were generated mainly from mechanical wear and friction processes at rail-wheel-brake interfaces. Carbonaceous, soil-derived, and secondary nitrate and/or sulfate particles observed in the underground subway particles likely flowed in from the outdoor environment by human activities and the air-exchange between the subway system and the outdoors. In addition, since the platform screen doors (PSDs) limit air-mixing between the tunnel and the platform, samples collected at the platform at the Yangjae station (with PSDs) showed a marked decrease in the relative abundances of Fe-containing particles compared to the Jegidong station (without PSDs).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.437-446
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• 2017

70 percent of Korea's territory is covered with mountains, whose difficult conditions can cause damage to facilities. Recently, the demand for facilities related to outdoor activities including monorails has been on the rise, and such facilities are much more likely to become damaged. For this reason, a monitoring system applying IoT to mountainous areas was developed and its applicability is evaluated in this study. The current status of the existing mountainous facilities and monitoring systems were reviewed, and the current wired monitoring technology was analyzed. A scenario for IoT-based monitoring was developed, and then sensor nodes were developed, which include an RF-communication module and interface, power-supply and solar-cell. A testbed was set up at K University. The same data was collected by the wireless system as had been collected by the wired one. The study findings are as follows. Firstly, by using the wireless system, it is estimated that the construction duration can be reduced by about 25 percent, while the construction costs can be reduced by about 3~52 percent. Secondly, the safety of the construction workers can be improved by making the working conditions less dangerous, such as by eliminating the need to transport cables.

• Journal of the Korean earth science society
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• v.28 no.6
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• pp.673-685
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• 2007

The purpose of this study was to investigate Earth Systems Understandings (Mayer, 1991) and Earth Systems meaning generation reported by science-talented students who participated in a geological field trip. The eight (4 female and 4 male students) field trip reports were randomly selected among all the reports written by twenty eighth-grade students who joined Shiwha-Lake field trip in Korea. The three-step program, including preparation, field trip, and summary, was provided to the students in order to facilitate meaningful learning through outdoor teaming activities. Seven Earth Systems Understandings and thematic types (Keys, 1999) were used to analyze the reports. The results of this study indicated thai aesthetic views and stewardship toward the Earth, which were the most distinguishing characteristics in Earth Systems Education, were reflected on most of the reports. The results also showed that the students tried to represent their understandings in such a type as meaning extension, meaning enhancement, or meaning elaboration. Overall, many students used 'knowledge-telling' process with a long list of observations and facts, whereas a few students used higher-order 'knowledge-transforming' process by coordinating their findings with interpretations and reasoning in their writings.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.735-750
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• 2015

The purpose of this study is to draw an educational implication by analyzing the context of narrative texts, students' narrative thinking, and their academic achievement. We investigated text types in students' geological field trip reports, the reason why students favors narrative texts, the relationship between narrative texts and their scientific knowledge recall, and the relationship between narrative thought and academic achievement. All students used expository texts, 82% of them expressed argumentative texts, and 36% of them used narrative texts. It is likely that students use more narrative texts because students were in the context of outdoor activity and so, their emotional feelings were more activated than when they are doing lab activities. The academic characteristics of earth science seemed to contribute more narrative texts in students' reports. The post-test revealed that students with narrative texts recalled better than the others. On the other hand, there were no statistically meaningful differences in academic achievement between the two groups. However, we have noted that female students whose reports contain narrative texts achieved significantly higher scores than female students whose reports are without narrative texts. From in-depth interviews, we found that students who properly used both paradigmatic and narrative mode of thought were in a more advantageous position than those who used narrative thought only. It was also found that some narratively thinking students tended to feel uncomfortable with the way of learning or evaluating questions about science. In the future, a complementary approach of narrative and paradigmatic mode of thoughts would be encouraged by understanding students' tendency of thinking.

• Nutritional Sciences
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• v.7 no.4
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• pp.208-213
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• 2004

In this study, we examined the effects of dietary 1,3-diacylglycerol (DG) compared to conventional triacylglycerol (TG) oil on the postprandial response of total and chylomicron TG, glucose, insulin, and free fatty acid (FFA). This study was conducted using a cross-over design. Ninety subjects participated in the high-fat meal tolerance test where they were randomly assigned to consume two experimental sandwiches containing mayonnaise with TG or DG oil with a seven-day interval. Blood samples were collected before ingestion and at 2, 3, 4 and 6 hr time point after ingestion and analyzed for total and chylomicron TG, glucose, insulin, FFA and phospholipid fatty acid composition. Both TG and DG ingestion had similar effects on postprandial TG response, but a different response from chylomicron TG. Compared with the TG group, TG levels were significantly lower only at 6 hr time point in the DG group. On the other hand, chylomicron TG rose steeply at 2 hr time point and decreased faster in this group. Also, the adjusted value to fasting levels was the same as the unadjusted level. Fasting levels and net differences in insulin were significantly lower at 3 hr time point where chylomicron TG levels were significantly lower in the DG group. But those of glucose and FFA in the TG and DG groups did not differ significantly. Fasting and postprandial levels of fatty acid composition in serum phospholipids in the two groups did not differ significantly. In conclusion, this study indicated that one could reduce the magnitude of postprandial lipemia without influencing glucose metabolism by consumning DG oil as a substitute for TG oil. Based on the correlation of coronary artery disease and postprandial lipemia, dietary DG ingestion might have a beneficial effect in treating such a disease. Further studies are required to clarify the long-tenn effects of dietary DG on blood lipid levels in humans.

• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.19-26
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• 1995

Ecological studies of Aedes togoi, the vector of malayan filariasis, were ci,wind out at Tolsando, Yosu and Sokcho area in 1991. The adult population of Aedes togoi was continuously appeared from the first week of April to the end of November showing the highest density in .truly. The larvae of Aedes togoi were found at rock pools from March to December in Sokcho area and the density was highest in July and August, whereas in the southern coastal area (Yosu), the larvae were found throughout the year and the density was the highest in Tune. The rate of larvae inhabited below 0.5% salinity was 45.7% in Sokcho and 51.7% in Yosu. The feeding activity of Aedes togoi was nocturnal, with the peak period of 01 :00-03:00 hours. Indoor feeding activities were slightly higher than outdoors showing the biting ratio of 1 :0.8 (indoor: outdoor). The average number of Aedes togoi attracted to CO2 gas was 8.5 whereas 117 Anophelei sinensis was attracted. The result indicates that CO2 is not an effective attractant for host seeking of Aedes togoi compared to Anopheles sineteis. The most common place was bedroom with 54.5% of total collections and next to stock place (18.2%), floor(9.1%) and kitchen (9.1%).

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.1-9
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• 2020

The purpose of this study is to verify the effects of ventilation corridor and derive adequate policy alternatives to its application for the city of Sejong, which is located in an inland of Korean Peninsula. In order to introduce the ventilation corridor in the city, it is necessary both to understand change on fresh air flow affected by the construction of new cities and to show its effects which are able to circulate air flow of the city. The study identified ventilation effects using computational fluid dynamics models. In particular, it analyzed change on wind speed and direction after constructing of a new town and cool air flow along the lowlands generated after sunset. In addition, it identified those of reducing particulate matter when arranging buildings conforming to the ventilation corridor at block level. The policy implications derived from simulation can be summarized as follows. First, it is desirable to plan ventilation corridors so that fresh air from mountains, forests, and valleys can flow into cities and mitigate the concentration of particulate matter. Furthermore, public facilities covering parks, plazas, and playgrounds should be installed preferentially to attract safe outdoor activities near to areas with low levels of particulate matter. Finally, it is adequate to prepare for a number of alternative plans by analyzing ventilation corridors when setting out district unit plan.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.420-427
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• 2019

Scrub typhus is a fever-related disease that is commonly diagnosed during the autumn season. The number of patients affected by this disease continues to increase every year. However, the cause of the disease and the regional differences of its incidence are poorly understood. This study examined the epidemiological features and regional differences in the incidence of scrub typhus. The monthly incidence of cases from all reports rose to more than 90% during the fall season (October~December). Based on the analysis of the 18,851 cases in the epidemiological investigation, 14,777 (78.4%) and 4,074 (21.6%) cases occurred in high and low occurrence areas, respectively. Moreover, there were more female cases than male cases (males: 7,233 [38.4%]; females: 11,618 [61.6%]; P< 0.001). The clinical symptoms, including fever, chills, myalgia, and eschar of the body, were noted in 16,688 (89.1%), 11,533 (61.2%),11,439 (60.7%), and 6,005 (45.4%) cases, respectively. The incidence rates were higher for Gyeongnam, Jeonam, Jeonbuk, and Chungnam provinces. The areas with a high occurrence of scrub typhus were consistent with the areas experiencing a high distribution of Leptotrombidium scutellare. The incidence of scrub typhus has been rising owing to the increasing population of ticks due to global warming and increased agricultural and outdoor activities. Thus, continuous management of patients and preventive environmental measures are needed to control this disease.

• Land and Housing Review
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• v.13 no.4
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• pp.1-12
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• 2022

Clean water is an essential urban infrastructure in human daily life, and water plays a vital role in public health. Due to restrictions on outdoor activities during COVID-19, time staying at home has increased. Therefore, it is plausible to assume that large-scale disaster incidences such as COVID-19 will affect water consumption. In this regard, this research aims to explore the factors that influence household water use during COVID-19. The analysis period of the study is 2020, and the geographical scope covers Seoul and Incheon. A dependent variable was water consumption in the autonomous districts of Seoul and Incheon, and the factors reflecting urban characteristics were used as independent variables. Multiple regression was used for analysis, and the unit of analysis was the autonomous district in Seoul and Incheon. The finding confirmed that the pandemic situation caused an increase in water consumption. In addition, it supports policy for the elderly so that they can use water without financial difficulty. It implies that a stable supply of clean water is essential for managing infectious diseases. The findings of this study are expected to provide some implications for efficient water supply policies and efficient water supply management in the event of the spread of infectious diseases such as COVID-19.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.857-866
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• 2020

'Movement' is an expanded concept of 'place' where people act, interact with one another and achieve a specific purpose at every moment. Wheelchairs, as a mobility aid, have a profound impact on improving the quality of physical and psychological well-being for the mobility disadvantaged groups who have mobility difficulties. Such mobility aids were developed mainly for outdoor activities, but in recent years, mobility aids for indoor spaces, the main living environment, are also being developed. Because indoor mobility aids generally move short distances repeatedly, this study examined the characteristics of lithium-ion batteries in short-distance driving of battery-powered wheelchairs and compared them with the characteristics of lithium-ion batteries in continuous driving. The result showed that the driving time for short-distance driving was 2.8% shorter than that of continuous driving. The current supplied to the motor was 15.4% higher for short-distance driving than that of continuous driving.