• Journal of Environmental Science International
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• v.29 no.8
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• pp.809-818
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• 2020

To conserve the population of a hesperiid butterfly, Leptalina unicolor, inhabiting the protected areas of Jaeyaksan, we provide ecological information on their behavior and propose habitat conservation measures, such as the creation of alternative habitats based on comprehensive information. The behavioral study used a method of re-capture after releasing the butterfly with enamel marks on the wings. Adult behaviors were shown in four patterns: flying, settling on a plant, nectar absorption, and water absorption. Both males and females had the highest proportion of flight movement overall; however, males had a slightly higher proportion of flight movement. As for duration, females spent more time settling on plants to select spawning sites, and males seemed to take a longer time for water absorption activities, to absorb minerals needed to form the spermatophore. The average travel distance of butterflies was 27.5 m for females and 46.7 m for males, with daily activity ranges from 11.2 m to 43.8 m, and 21.4 to 57.6 m, respectively. The most important condition to preserve the habitat of Leptalina unicolor is to maintain the community of Miscanthus sinensis, a food plant. Additionally, because this butterfly has a high rate of water absorption activities, wetlands should be maintained.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.169-180
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• 2020

The purpose of this study was to find the characteristics of the foreign and domestic travels and to seek out the significance of the study, by grouping the geotweets users who moved abroad, according to the average and the standard deviation of moving distances. Geotweets which caused foreign and domestic travels occurred divided, after building a data mart and the moving distances of users were measured by using the Haversine formula. It has moved more often among groups of foreign travelers in countries that use the same language and have similar lifestyles. There has been a lot of movement in developed countries with well-established infrastructure in a group of domestic travelers. This study tried to draw common features, by calculating the travel distances by each user and grouped users according to the characteristics of user's moving distances. There are significant differences in national economic power, age, jobs, etc. among users from a total of 21 countries analyzed by this study, so a more precise analysis would be able to be conducted, only if the whole conditions are considered. A future study should additionally consider real factors.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.129-139
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• 2010

This study proposes a model for measuring the connectivity of nodes in road networks. The connectivity index between two nodes is characterized by the number of routes, degree of circuitousness, design speed, and route capacity between the nodes. The connectivity index of a node is then defined as the weighted average of the connectivity indexes between the node and other nodes under consideration. The weighting factor between two nodes is determined by the travel demand and distance between them. The application of the model to a toy network shows that it reasonably well quantifies the level of connectivity of nodes in the network. If flow of rail networks can be measured in the same scale as that of road networks and the capacity of rail links can be estimated, the model proposed in this paper could be applied to intermodal transportation networks as well.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.117-123
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• 2017

This study was intended to find methods of fire extinguishing system designs that can improve the equipment's usability. In this study, the fire suppression experiment through fire extinguishers and the data drawn through the experiment were analyzed, and then the guideline for the improvement of designs was presented. The procedure is as follows. A fire suppression experiment with the use of fire extinguishers was done by 43 average adults. The whole process of the fire suppression was videotaped, and then captured major scenes were analyzed with the use of RULA, a human engineering measurement tool. The analyzed data were divided into 4 steps, and then the guideline for design improvement was presented. The summary of the study is as follows. Step 1, Fire extinguisher distance step. To reduce overload occurring at the process of holding fire extinguishers suddenly, wheels are attached to the body of extinguishers, or pedestals are installed. Step 2, Fire extinguisher transportation step. The length of hose is extended, or fire fighting water is sprayed far, so that overload of legs occurring at the process of travel can be reduced. In addition, the weight of fire extinguisher shouldn't be over 2 kg. Step 3, Safety pin removal stage. Safety pins should be applied with button type, so that excessive posture of lower limbs and excessive twisting of wrists won't happen during safety pin removal process. Besides, safety pins should be designed for easy identification and operation. Step 4, Fire extinguishing agent spraying step. To reduce overload occurring at sudden spraying of fire fighting water, pressure should be increased gradually until high pressure. With the above study results applied to existing fire extinguisher design, it may contribute to reducing any fire damage.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.75-82
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• 2005

To relieve congestion in the current system of intercity transportation, the Korea decided in 1990 to construct a high-speed railroad between Seoul and Busan and it is now in operation. This new mode of transportation significantly cut travel time between major cities and a trip from Seoul to the southeastern port of Busan. Since the KTX opening, average daily passenger numbers on both the Gyeongbu and Honam lines have increased about 1.3 fold over 2003 levels. As of December 2004, the KTX trains are carrying about 81,000 people a day. On KTX routes, the daily number of airline passengers dropped. Express long-distance bus traffic also dropped by 20% to 30%, while that on short-distance routes (100km or less) increased by about 20%. These figures clearly indicate that the Korean transportation network is becoming railroad-centric. However, the number of KTX passengers is fewer than anticipated possibly due to the Korean economic downturn and the operation of the KTX will leave many existing Saemaul and Mugunghwa train sets idle, which will be put into operation for areas, not covered by the KTX. When all the existing major lines have been electrified, more high-speed rail services will be phased in using direct connections to maximize operational efficiency. And also, the dual management by KTX and conventional rail will be regarded as the promotion of the benefit of the public.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.351-373
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• 2019

The cold eddies around the Ulleung Basin in the East Sea were identified from satellite altimeter sea level data using the Winding-Angle method from 1993 to 2015. Among the cold eddies, the Dokdo Cold Eddies (DCEs), which were formed at the first meandering trough of the East Korea Warm Current (EKWC) and were pinched off to the southwest from the eastward flow, were classified and their migration patterns were analyzed. The vertical structures of water temperature, salinity, and flow velocity near the DCE center were also examined using numerical simulation and observation data provided by the Hybrid Coordinate Ocean Model and the National Institute of Fisheries Science, respectively. A total of 112 DCEs were generated for 23 years. Of these, 39 DCEs migrated westward and arrived off the east coast of Korea. The average travel distance was 250.9 km, the average lifespan was 93 days, and the average travel speed was 3.5 cm/s. The other 73 DCEs had moved to the east or had hovered around the generated location until they disappeared. At 50-100 m depth under the DCE, water temperature and salinity (T < $5^{\circ}C$, S < 34.1) were lower than those of ambient water and isotherms made a dome shape. Current faster than 10 cm/s circulates counterclockwise from the surface to 300 m depth at 38 km away from the center of DCE. After the EKWC separates from the coast, it flows eastward and starts to meander near Ulleungdo. The first trough of the meander in the east of Ulleungdo is pushed deep into the southwest and forms a cold eddy (DCE), which is shed from the meander in the south of Ulleungdo. While a DCE moves westward, it circumvents the Ulleung Warm Eddy (UWE) clockwise and follows U shape path toward the east coast of Korea. When the DCE arrives near the coast, the EKWC separates from the coast at the south of DCE and circumvents the DCE. As the DCE near the coast weakens and extinguishes about 30 days later after the arrival, the EKWC flows northward along the coast recovering its original path. The DCE steadily transports heat and salt from the north to the south, which helps to form a cold water region in the southwest of the Ulleung Basin and brings positive vorticity to change the separation latitude and path of the EKWC. Some of the DCEs moving to the west were merged into a coastal cold eddy to form a wide cold water region in the west of Ulleung Basin and to create a elongated anticlockwise circulation, which separated the UWE in the north from the EKWC in the south.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.67-85
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• 2018

Vehicle platooning through wireless communication and automated driving technology has become realized. Platooning is a technique in which several vehicles travel at regular intervals while maintaining a minimum safety distance. Truck platooning is of keen interest because it contributes to preventing truck crashes and reducing vehicle emissions, in addition to the increase in truck flow capacity. However, it should be noted that interactions between vehicle platoons and adjacent manually-driven vehicles (MV) significantly give an impact on the performance of traffic flow. In particular, when vehicles entering from on-ramp attempt to merge into the mainstream of freeway, proper interactions by adjusting platoon size and inter-platoon spacing are required to maximize traffic performance. This study developed a methodology for establishing operational strategies for truck platoonings on freeway on-ramp areas. Average speed and conflict rate were used as measure of effectiveness (MOE) to evaluate operational efficiency and safety. Microscopic traffic simulation experiments using VISSIM were conducted to evaluate the effectiveness of various platooning scenarios. A decision making process for selecting better platoon operations to satisfy operations and safety requirements was proposed. It was revealed that a platoon operating scenario with 50m inter-platoon spacing and the platoon consisting of 6 vehicles outperformed other scenarios. The proposed methodology would effectively support the realization of novel traffic management concepts in the era of automated driving environments.

• Journal of Korean Society of Transportation
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• v.21 no.3
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• pp.47-56
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• 2003

Considering the high density developments along the major traffic corridors in Seoul, transit-oriented street designs will be a very effective to control traffic congestion along the corridors. For testing the effectiveness, we selected. for our case study, Kangnam Street, which is one of the most highly developed corridors in Seoul The traffic study on Kangnam street in 2000 shows that the daily average bus speed is 11.73km/h, which is 5km/h lower than the auto speed. The Central Bus Lane system was applied on the Kangnam street to test impact on bus speed as well as auto speed. Simulation results show that with Central Bus Lane have been improved the travel speeds of bus as well as auto on Kangnam street from 14.4km/hr to 35.0km/hr and from 25.1km/hr to 26.1km/hr, respectively. The bus market share increases about 6-8 percentages. Especially, 13.4% of bus users are increased for long-distance trips.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.2060-2077
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• 2019

Recently, mobile healthcare services have attracted significant attention because of the emerging development and supply of diverse wearable devices. Smartwatches and health bands are the most common type of mobile-based wearable devices and their market size is increasing considerably. However, simple value comparisons based on accumulated data have revealed certain problems, such as the standardized nature of health management and the lack of personalized health management service models. The convergence of information technology (IT) and biotechnology (BT) has shifted the medical paradigm from continuous health management and disease prevention to the development of a system that can be used to provide ground-based medical services regardless of the user's location. Moreover, the IT-BT convergence has necessitated the development of lifestyle improvement models and services that utilize big data analysis and machine learning to provide mobile healthcare-based personal health management and disease prevention information. Users' health data, which are specific as they change over time, are collected by different means according to the users' lifestyle and surrounding circumstances. In this paper, we propose a prediction model of user physical activity that uses data characteristics-based long short-term memory (DC-LSTM) recurrent neural networks (RNNs). To provide personalized services, the characteristics and surrounding circumstances of data collectable from mobile host devices were considered in the selection of variables for the model. The data characteristics considered were ease of collection, which represents whether or not variables are collectable, and frequency of occurrence, which represents whether or not changes made to input values constitute significant variables in terms of activity. The variables selected for providing personalized services were activity, weather, temperature, mean daily temperature, humidity, UV, fine dust, asthma and lung disease probability index, skin disease probability index, cadence, travel distance, mean heart rate, and sleep hours. The selected variables were classified according to the data characteristics. To predict activity, an LSTM RNN was built that uses the classified variables as input data and learns the dynamic characteristics of time series data. LSTM RNNs resolve the vanishing gradient problem that occurs in existing RNNs. They are classified into three different types according to data characteristics and constructed through connections among the LSTMs. The constructed neural network learns training data and predicts user activity. To evaluate the proposed model, the root mean square error (RMSE) was used in the performance evaluation of the user physical activity prediction method for which an autoregressive integrated moving average (ARIMA) model, a convolutional neural network (CNN), and an RNN were used. The results show that the proposed DC-LSTM RNN method yields an excellent mean RMSE value of 0.616. The proposed method is used for predicting significant activity considering the surrounding circumstances and user status utilizing the existing standardized activity prediction services. It can also be used to predict user physical activity and provide personalized healthcare based on the data collectable from mobile host devices.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.443-451
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• 2010

This paper proposes the methodology about advisory safety speed based on real-time vehicular data collected from highway. The proposed model is useful information to drivers by appling seamless wireless communication and being collected from ECU(Engine Control Unit) equipment in every vehicle. Furthermore, this model also permits the use of realtime sensing data like as adverse weather and road-surface data. Here, the advisory safety speed is defined "the safety speed for drivers considering the time-dependent traffic condition and road-surface state parameter at uniform section", and the advisory safety speed model is developed by considering the parameters: inter-vehicles safe stopping distance, statistical vehicle speed, and real-time road-surface data. This model is evaluated by using the simulation technique for exploring the relationships between advisory safety speed and the dependent parameters like as traffic parameters(smooth condition and traffic jam), incident parameters(no-accident and accident) and road-surface parameters(dry, wet, snow). A simulation's results based on 12 scenarios show significant relationships and trends between 3 parameters and advisory safety speed. This model suggests that the advisory safety speed has more higher than average travel speed and is changeable by changing real-time incident states and road-surface states. The purpose of the research is to prove the new safety related services which are applicable in SMART Highway as traffic and IT convergence technology.