• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.613-621
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• 2019

The purpose of this study is to evaluate the effectiveness of supportive devices which are for minimizing the patient's movement during lower extremity angiography and to verify image quality of phantom by analyzing of Mask image, DSA image and Roadmap image into SNR and CNR. As a result of comparing SNR with CNR of mask image obtained by DSA technique using the phantom alone and phantom placed on the supportive devices, there was no significant difference between about 0~0.06 for SNR and about 0~0.003 for CNR. The study showed about 0.11~0.35 for SNR and 0.016~0.031 for CNR of DSA imaging by DSA technique about only water phantom of the blood vessel model and the water phantom placed on the device. Analyzing SNR and CNR of Roadmap technique about water phantom on the auxiliary device (hardboard paper, pomax, polycarbonate, acrylic) and water phantom alone, there was no significant difference between 0.02~0.05 for SNR and 0.002~0.004 for CNR. In conclusion, there was no significant difference on image quality by using supportive devices made by hardboard paper, pomax, polycarbonate or acryl regardless of whether using supportive devices or not. Supportive devices to minimize of the patient's movement may reduce the total amount of contrast, exam-time, radiation exposure and eliminate risk factors during angiogram. Supportive devices made by hardboard paper can be applied easily during angiogram due to advantages of reasonable price and simple processing. It is considered that will be useful to consider cost efficiency and types of materials and their properties in accordance with purpose and method of the study when the operator makes and uses supportive devices.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.1
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• pp.76-87
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• 2019

The purpose of this study was to evaluate the performance of and to derive future maintenance-management measures of the constructed alternative habitat for the Kaloula borealis at the University of Seoul, examining the period between 2015-2017. The research was constructed in 2014 and in a $191m^2$ area. The performance evaluation was divided into maintaining the habitat of the target species, maintaining the population and reproduction rates of the target species, maintaining the habitat of the wild species, the resilience of natural ecosystems, and the harmony with the surrounding environment. In terms of maintaining the habitat of the target species, soil collected from the existing habitat of the Kaloula borealis and was the depth was increased to 30cm in the alternative habitat. An artificial water supply was required every year during the supporting the spawning and hatching of other amphibians along with the Kaloula borealis. The sources of water of the alternative habitat were both rain and tap water, as it cannot be maintained naturally. Additionally, the Kaloula borealis thrived because it inhabited the research site and the average temperature was $26.2^{\circ}C$ from April-June, which is when the Kaloula borealis spawns. In terms of maintaining the population and reproduction rates of the Kaloula borealis, they were evaluated to have stable rates of reproduction. In terms of maintaining the habitat of the wild species, studies on vegetation and the structure of the characteristics of prey or predators will be needed. Also, alien species, such as Humulus japonicus and Bidens frondosa needed to be removed to maintain the wetland ecosystem of the wild species. In the assessment of the resilience of the natural ecosystems, the mud was monitored, noting the changes in the depth of water, with steps taken to reduce the leakage of water. The mud collected from the Haneul Pond wetland, which is located around the research site was piled up. Also, partial mowing management and the inducement of a natural vegetation colony was required for vegetation management. It was also necessary to create porous spaces, such as old trees and tree branches to create a habitat with hiding places and feeding and spawning places for small organisms. In terms of the harmony with the surrounding environment, the following threat factors needed to be managed: amphibian roadkill by vehicles and pedestrians and artificial draining due to nearby user access. Based on the monitoring results, alternative habitat management measures presented the promoting various waterside structures, in which amphibians can spawn and hide in, managing the water environment consistently, managing the vegetation, focused on the habitat of the wild species, and managing the surrounding environment for the habitat. The creation of an alternative habitat should be managed through monitoring, reflecting the characteristics of the changes in the site. Also continuing efforts are also needed to improve the habitat of the target species.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.314-320
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• 2021

With the increasing age of motherhood in recent years, attributed to late marriages due to social or environmental factors, the Down's syndrome screening test using biochemical markers has become essential for pregnant women. The process of diagnosing Down's syndrome pregnancy in the high-risk group subjects involves chromosomal analysis, which is performed on samples obtained through invasive procedures such as chorionic biopsy or amniotic fluid. Thus, to reduce unnecessary invasive tests and lower the risk to mother and fetus, it is important to identify a screening test with low risk and high Down's syndrome detection rate. Recently, as the average age of mothers has increased, numerous inspection agencies have classified high-risk mothers as women over the age of 35 years. This study evaluated a total of 36,436 pregnant women aged between 17 to 46 years, and who requested prenatal screening at an inspection agency in Yongin in 2018. Test (13,690 people) Four tests were conducted by applying the time-resolved fluoroimmunoassay method using the direct sandwich and indirect sandwich technology, and the immunoassay method using the sandwich method. We aimed to confirm the difference in positivity rate with increasing age of the subjects. We believe that in future, data obtained from this study will be very useful for the prevention and treatment of Down's syndrome risk at varied inspection institutions, and for prospective mothers.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.206-219
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• 2021

The warming of the climate is increasing the damage caused by termites to wooden buildings, cultural properties and houses. A group removal system can be installed around the building to detect and remove termite damage; however, if the site is not visited regularly, every one to two months, you cannot observe whether termites have spread within, and it is difficult to take prompt effective action. In addition, since the system is installed and operated in an exposed state for a long period of time, it may be ineffective or damaged, resulting in a loss of function. Furthermore if the system is installed near a cultural site, it may affect the aesthetic environment of the site. In this study, we created a detection system that uses wood, cellulose, magnets, and magnetic sensors to determine whether termites have entered the area. The data was then transferred to a low power LoRa Network which displayed the results without the necessity of visiting the site. The wood was made in the shape of a pile, and holes were made from the top to the bottom to make it easier for termites to enter and produce a cellulose sample. The cellulose sample was made in a cylindrical shape with a magnet wrapped in cellulose and inserted into the top of a hole in the wood. Then, the upper part of the wood pile was covered with a stopper to prevent foreign matter from entering. It also served to block external factors such as light and rainfall, and to create an environment where termites could add cellulose samples. When the cellulose was added by the termites, a space was created around the magnet, causing the magnet to either fall or tilt. The magnetic sensor inside the stopper was fixed on the top of the cellulose sample and measured the change in the distance between the magnet and the sensor according to the movement of the magnet. In outdoor experiments, 11 cellulose samples were inserted into the wood detection system and the termite inflow was confirmed through the movement of the magnet without visiting the site within 5 to 17 days. When making further improvements to the function and operation of the system it in the future, it is possible to confirm that termites have invaded without visiting the site. Then it is also possible to reduce damage and fruiting due to product exposure, and which would improve the condition and appearance of cultural properties.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.6
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• pp.167-187
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• 2020

Currently, Korea is changing into an ultra-aging society, and office workers retire at the age of 49.5 on average from their main jobs, and the national pension is delayed from 62 years old to 65 years old by 2034, so research is needed to prepare for the aging of office workers after retirement. The purpose of this study is to examine the factors affecting the intention to start a business after retirement and the mediating effect of another sense of success expectation on life after retirement, targeting office workers nationwide. Changes in individual attitudes and systematic institutional support are needed to prepare for a sustainable job until the age of 100 after retirement, that is, a start-up utilizing wisdom and experience in work life. As a result of the study, the ability to perform the goal as job performance, economic preparation for retirement preparation, preparation for external relations, and future anxiety have a positive effect on the entrepreneurial will, and the ability to use new technologies as job performance, and physical preparation for retirement. Preparation and preparation for internal relations were found to have no effect. In the influencing relationship between preparation for external relations and the will of start-up, and future anxiety and will of start-up, another sense of success was confirmed to have a partial mediation effect. In the relationship between economic preparation and willingness to start a business, the effect of complete mediation was confirmed. In order to increase the will to start a business after retirement, it was confirmed that another sense of expectation for success was an important variable. Introducing a government-sponsored education system in the company to reduce the government's financial burden due to super-aging and achieve corporate growth through employee training while potential founders, office workers, are employed, and entrepreneurship and goals for the three life goals of office workers By introducing a performance improvement program, we were able to get implications that would be a solution to the growth of individuals and businesses and reducing the government's financial burden.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.85-93
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• 2021

The seventy percentage of Korean Peninsular is covered by the mountainous area, and the depth of west sea and south sea is relatively shallow. Therefore, a large scale land reclamation from the sea has been implemented for the construction of industrial complex, residental area, and port and airport facilities. The common problem of reclaimed land is consisted of soft ground, and hence it has low load bearing capacity as well as excessive settlement upon loading on the ground surface. The hollow concrete block has been used to reinforce the loose and soft foundation soil where the medium-high apartment or one-story industrial building is being planned to be built. Recently the earthquakes with the magnitude of 4.0~5.0 have been occurred in the west coastal and southeast coastal areas. Lee (2019) reported the advantages of hollow concrete block reinforced shallow foundation through the static laboratory bearing capacity tests. In this study, the dynamic behavior of hollow concrete block reinforced sandy ground with filling the crushed stone in the hollow space has been investigated by the means of shaking table test with the size of shaking table 1000 mm × 1000 mm. Three types of seismic wave, that is, Ofunato, Hachinohe, Artificial, and two different accelerations (0.154 g, 0.22 g) were applied in the shaking table tests. The horizontal displacement of structure which is situated right above the hollow concrete block reinforced ground was measured by using the LVDT. The relative density of soil ground are varied with 45%, 65%, and 85%, respectively, to investigate the effectiveness of reinforcement by hollow block and measured the magnitude of lateral movement, and compared with the limit value of 0.015h (Building Earthquake Code, 2019). Based on the results of shaking table test for hollow concrete block reinforced sandy ground, honeycell type hollow block gives a large interlocking force due to the filling of crushed stone in the hollow space as well as a great interface friction force by the confining pressure and punching resistance along the inside and outside of hollow concrete block. All these factors are contributed to reduce the great amount of horizontal displacement during the shaking table test. Finally, hollow concrete block reinforced sandy ground for shallow foundation is provided an outstanding reinforced method for medium-high building irrespective of seismic wave and moderate accelerations.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.127-135
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• 2021

To respond to the threat of global warming, countries around the world are promoting the spread of renewable energy and reduction of carbon emissions. In accordance with the United Nation's Sustainable Development Goal to combat climate change and its impacts, global automakers are pushing for a full transition to electric vehicles within the next 10 years. Electric vehicles can be a useful means for reducing carbon emissions, but in order to reduce carbon generated in the stage of producing electricity for charging, a power generation system using eco-friendly renewable energy is required. In this study, we propose a smart electric mobility operating system integrated with off-grid solar power plants established in Tanzania, Africa. By applying smart monitoring and communication functions based on Arduino-based computing devices, information such as remaining battery capacity, battery status, location, speed, altitude, and road conditions of an electric vehicle or electric motorcycle is monitored. In addition, we present a scenario that communicates with the surrounding independent solar power plant infrastructure to predict the drivable distance and optimize the charging schedule and route to the destination. The feasibility of the proposed system was verified through test runs of electric motorcycles. In considering local environmental characteristics in Tanzania for the operation of the electric mobility system, factors such as eco-friendliness, economic feasibility, ease of operation, and compatibility should be weighed. The smart electric mobility operating system proposed in this study can be an important basis for implementing the SDGs' climate change response.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.567-582
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• 2022

Chainsaw use for motor-manual timber harvesting in South Korea is associated with worker safety issues. However, forestry operations such as timber harvesting have already been mechanized to reduce hazards to workers and increase productivity. This study analyzed the productivities and costs of felling and processing, felling and processing using an excavator-based stroke harvester for Pinus rigida and Quercus mongolica stands. To efficiently operate the stroke harvester, we developed a regression equation to estimate the productivities of felling and processing, felling, and processing operations,and we conducted sensitivity analysis of the operation costs using DBH and machine utilization. The felling and processing productivity was 6.53 and 4.02 m³/SMH for P. rigida a nd Q. mongolica, respectively, and the cost was 17,983 and 29,210 won/m³, respectively. The felling productivity for P. rigida a nd Q. mongolica wa s 40.9 and 23.0 m³/SMH, respectively, and the cost was 2,667 and 4,743 won/m³, respectively. The processing productivity for P. rigida and Q. mongolica was 8.25 and 7.75 m³/SMH, respectively, and the cost was 15,296 and 16,283 won/m³, respectively. In the developed regression equation, the DBH, traveling distance, and number of cuttings were found to be important factors (p<0.05). Therefore, it is necessary to construct a DB considering the various conditions and species associated with harvester operations, and further research is needed to increase the accuracy of predicting operation productivity and costs.

• Journal of fish pathology
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• v.35 no.1
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• pp.1-25
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• 2022

The aquaculture industry has developed rapidly over the last three decades and is an important industry that supplies over 15% of humans' animal protein intake; therefore, there is a need to increase production to meet the continuous demand. The fish cage farms on the southern coast (Kyengsangnam-do and Jeollanam-do) of Korea are critical resources in aquaculture because they account for approximately 90% of the national total fish cage farms by water area ratio. However, the current aquaculture environment is being gradually affected by climate change, which is a global issue, and its effects are expected to intensify in the future. Therefore, it is urgently imperative to accurately evaluate the effects of climate change on South Korean aquaculture industries and to develop social and national strategies to minimize damage to the fishing industry. The damage to fish farmed in cage farms on the southern coast is increasing annually and the leading causes are high and low water temperature and red tides, which are directly or indirectly related to climate change. At present, global warming can provide opportunities for aquaculture industrialization of fish or other novel species, with economic implications. However, despite such opportunities, the influx of new species can also cause problems such as ecological disturbances, increase in the reproduction frequency of microalgae such as red tide, increase in disease incidence, and occurrence and periods of high water temperatures in summer. The scale of farmed fish mortality is increasing due to the complex effects of these factors. Increased damages due to fish mortality not only have severe economic impacts on the aquaculture industry, but the social costs of responding to the damage and follow-up measures also increase. various active responses can reduce the mortality damage in fish farms such as improving the management skills in aquaculture, improved species breeding, efficient food management, disease prevention, proactive responses, and system-wide improvements. This review article analyzes the large-scale mortality cases occurring in fish cage farms on the southern coast of Korea and proposes measures to mitigate mortality and enhance responses to such scenarios.

• Ecology and Resilient Infrastructure
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• v.9 no.1
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• pp.36-58
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• 2022

In this study, the weather conditions corresponding to the increase in the environmental concentration of fine dust (PM₁₀) and ultrafine dust (PM_2.5) from 2001 to 2019 in Jeju and Seogwipo cities were analyzed. The increase in the levels of PM₁₀ and PM_2.5 was observed in the order: spring > winter > autumn > summer. In both cities, PM₁₀ and PM_2.5 levels increased more frequently during the day in spring and summer and at night in autumn and winter, with PM_2.5 showing a greater increase in concentration than PM₁₀. The air temperature and wind speed corresponding with increased levels of PM₁₀ were higher than their respective seasonal averages in spring and winter, but lower in summer and autumn. Relative humidity was lower than the seasonal average during all seasons. The air temperature variation corresponding with increased levels of PM_2.5 showed the same seasonal trend as that observed for PM₁₀. The relative humidity was higher than the respective seasonal averages in spring and summer, and lower in winter. The wind speed was lower than the seasonal average in both the cities. When the PM₁₀ and PM_2.5 levels increased, the wind direction was from the north and the west during the day and varied according to the season at night. The rate of the increase in the PM₁₀ concentration was the highest in both cities at the wind speed of 1.6 - 3.4 ms^-1 during the day and night except during night in the summer. The highest concentration of PM_2.5 was observed with the wind speed range of 1.6 - 3.4 ms^-1 in Jeju, and 0.3 - 1.6 ms^-1 in Seogwipo. The results of this study applied to urban and landscape planning will aid in the formulation of strategies to reduce the adverse effects of fine particular matter.