• Journal of the Korean Geographical Society
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• v.19
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• pp.41-51
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• 1979

Since 1971 when the nation wide 'New Community' movement was launched to improve rural standards of living, dol and thatched-roof houses have been reshaped or removed, thereby making it hard to find time-honored people's living structures in the countryside. Since 1977, the improvement work of rural houses has started throughout the country, so many new rural residences have been constructing along the highway, main roads, railways and around the sightseeing area, New rural houses do not show, for the most part, the traditional architectural style and the nation's unique conventional ways of living. The writer tried to find solutions to the problems derived from improvement work of rural residence, in a comparative method of traditional rural houses and newly constructed rural ones. The greater part of new rural houses' types, painting colors, and fence types had been recommended by provincial administrative trative officials. Officials recommended them to the farmer with their standards, which did not consider farmer's convenience of traditional way of life, but a fine sight from the highways or railways. Korea's three basic roof types are the HAPKAK roof (gabled and hipped), the UCHINKAK roof(hipped), and the BAKKOONG roof(gabled). However, the gabled roof houses, having their entrance on the gabled side, are found more ofter in new rural village. As mentioned above, architectural style is not harmonious with the topography and climate i Korea, because it is not Korean traditional type, but one of the western styles. And new rural house plans are inconvenient in the conservation rural family system, because of the same category with urban houses plans. Other problems derived from ton-traditional architecture style are roof painting in 4-5 colors in a new village, types of wall and fence, and attached building in the site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5135-5142
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• 2011

A flexible mechanism is proposed in this paper to improve the dynamic response performance of a traffic flow control system in an urban area. The roads, vehicles, and traffic control systems are all modeled as intelligent systems, wherein a wireless communication network is used as the medium of communication between the vehicles and the roads. The necessary sensor networks are installed in the roads and on the roadside upon which reinforcement learning is adopted as the core algorithm for this mechanism. A traffic policy can be planned online according to the updated situations on the roads, based on all the information from the vehicles and the roads. This improves the flexibility of traffic flow and offers a much more efficient use of the roads over a traditional traffic control system. The optimum intersection signals can be learned automatically online. An intersection control system is studied as an example of the mechanism using Q-learning based algorithm, and simulation results showed that the proposed mechanism can improve the traffic efficiency and the waiting time at the signal light by more than 30% in various conditions compare to the traditional signaling system.

• Journal of Power System Engineering
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• v.22 no.6
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• pp.51-57
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• 2018

In Korea, the Air Quality Conservation Act and the Petroleum and Petroleum Substitute Fuel Business Act stipulate certain quality standards for fuels distributed in Korea, thereby striving to reduce vehicle performance and emissions. Domestic petroleum products import and produce all the crude oil from each oil refiner so that the quality of the petroleum product is different according to the characteristics of the crude oil. As a result, vehicles have been improved by using the physical properties calculated through the physical property measurement that has tried to improve the accuracy of the measurement of the energy consumption efficiency of the automobile by using standard fuel from abroad. In this study, the same test procedure and method as the test method of domestic gasoline vehicle emission are applied using four samples of gasoline and the latest gasoline vehicle which are actually distributed, and the performance evaluation is performed. The purpose of this study is to contribute to improvement of vehicle technology and fuel quality by collecting necessary basic data and obtaining data on the effect of differences in gasoline property on vehicle emissions. The results of the test showed that the emission of gases (NMOG, CO) from gasoline vehicles was the most influenced by the sulfur content, unlike the previous studies that the vehicles emission had the greatest influence on the distillation characteristics and the specific gravity of aromatic compounds. The catalytic reaction such as the poisoning action of the three-way catalyst which is the abatement device was interfered and the emission was increased. The distillation characteristics and specific gravity of aromatic compounds were found to affect the emission of vehicles. According to the physical properties of the fuel, the emission difference was 28.0% in the urban mode and 17.6 % in the highway mode.

• Earthquakes and Structures
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• v.17 no.4
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• pp.411-424
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• 2019

In this study, a numerical model of a shield tunnel with an assembled segmental lining was built. The seismic response of the segmental lining of the section of the shield tunnel in Line 1 of the Chengdu Metro is analyzed as it passes through the interface of sand-cobble and mudstone layers. To do so, the node-stress seismic-motion input method was used to input the seismic motion measured during the 2008 Wenchuan earthquake, and the joint openings and dislocations associated with the earthquake action were obtained. With reference to the Ethylene-Propylene-Diene Monomer (EPDM) sealing gaskets used in the shield tunnels in the Chengdu Metro, numerical simulation was applied to analyze the contact pressure along the seepage paths and the waterproof property under different joint openings and dislocations. A laboratory test on the elastic sealing gasket was also conducted to study its waterproof property. The test results accord well with the numerical results and the occurrence of water seepage in the section of the shield tunnel in Line 1 of the Chengdu Metro during the 2008 Wenchuan earthquake was verified. These research results demonstrate the deformation of segmental joint under earthquake, also demonstrate the relationship between segmental joint deformation and waterproof property.

• The Journal of Bigdata
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• v.6 no.1
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• pp.1-12
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• 2021

The rapid growth of mobile-based online shopping and the appearance of untact business initiated by COVID-19 has led to an explosive increase in demand for logistics services such as delivery services. In order to respond to the rapidly growing demand, most logistics and distribution companies are working to improve customer service levels through the establishment of a full-filament center in the city center. However, due to social factors such as high land prices and traffic congestion, it becomes more difficult to establish the logistics facilities in the city center. In this study, it has been proposed the way to choose the candidate locations for the shared distribution centers among the space nearby the tall-gate which can be idle after the smart tolling service is widely extended. In order to evaluate the candidate locations, it has been evaluated the centralities of all candidates using social network analysis (SNA). To understand the result considering the characteristics of centrality, the network structure was regenerated based on the distance and the traveling time, respectively. It is possible to refer the result of evaluation based on the cumulative relative importance to choose the best set of candidates.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3858-3874
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• 2021

As an essential part of the urban transportation system, precise perception of the traffic flow parameters at the traffic signal intersection ensures traffic safety and fully improves the intersection's capacity. Traditional detection methods of road traffic flow parameter can be divided into the micro and the macro. The microscopic detection methods include geomagnetic induction coil technology, aerial detection technology based on the unmanned aerial vehicles (UAV) and camera video detection technology based on the fixed scene. The macroscopic detection methods include floating car data analysis technology. All the above methods have their advantages and disadvantages. Recently, indoor location methods based on wireless signals have attracted wide attention due to their applicability and low cost. This paper extends the wireless signal indoor location method to the outdoor intersection scene for traffic flow parameter estimation. In this paper, the detection scene is constructed at the intersection based on the received signal strength indication (RSSI) ranging technology extracted from the wireless signal. We extracted the RSSI data from the wireless signals sent to the road side unit (RSU) by the vehicle nodes, calibrated the RSSI ranging model, and finally obtained the traffic flow parameters of the intersection entrance road. We measured the average speed of traffic flow through multiple simulation experiments, the trajectory of traffic flow, and the spatiotemporal map at a single intersection inlet. Finally, we obtained the queue length of the inlet lane at the intersection. The simulation results of the experiment show that the RSSI ranging positioning method based on wireless signals can accurately estimate the traffic flow parameters at the intersection, which also provides a foundation for accurately estimating the traffic flow state in the future era of the Internet of Vehicles.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.663-671
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• 2020

Recently, there have been many natural disasters in Korea, not only in forest areas but also in urban areas, and the national requirements for them are increasing. In particular, there is no pre-disaster information system that can systematically manage the collapse of the slope of the national highway. In this study, big data analysis was conducted on the factors causing slope collapse based on the detailed investigation report on the slope collapse of national roads in Gangwon-do and Gyeongsang-do areas managed by the Cut Slope Management System (CSMS) and the basic survey of slope failures. Based on the analysis results, a slope collapse risk prediction model was established through Adaboost, a classification-based machine learning model, reflecting the collapse slope location and weather information. It also developed a visualization map for the risk of slope collapse, which is a visualization program, to show that it can be used for preemptive disaster prevention measures by identifying the risk of slope due to changes in weather conditions.

• Steel and Composite Structures
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• v.45 no.2
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• pp.205-218
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• 2022

Proper calculation of splitting tensile strength (STS) of concrete has been a crucial task, due to the wide use of concrete in the construction sector. Following many recent studies that have proposed various predictive models for this aim, this study suggests and tests the functionality of three hybrid models in predicting the STS from the characteristics of the mixture components including cement compressive strength, cement tensile strength, curing age, the maximum size of the crushed stone, stone powder content, sand fine modulus, water to binder ratio, and the ratio of sand. A multi-layer perceptron (MLP) neural network incorporates invasive weed optimization (IWO), cuttlefish optimization algorithm (CFOA), and electrostatic discharge algorithm (ESDA) which are among the newest optimization techniques. A dataset from the earlier literature is used for exploring and extrapolating the STS behavior. The results acquired from several accuracy criteria demonstrated a nice learning capability for all three hybrid models viz. IWO-MLP, CFOA-MLP, and ESDA-MLP. Also in the prediction phase, the prediction products were in a promising agreement (above 88%) with experimental results. However, a comparative look revealed the ESDA-MLP as the most accurate predictor. Considering mean absolute percentage error (MAPE) index, the error of ESDA-MLP was 9.05%, while the corresponding value for IWO-MLP and CFOA-MLP was 9.17 and 13.97%, respectively. Since the combination of MLP and ESDA can be an effective tool for optimizing the concrete mixture toward a desirable STS, the last part of this study is dedicated to extracting a predictive formula from this model.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.39-49
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• 2011

The porous pavement system is widely considered very effective in urban street because of its various benefits on safety and environment, but the pavement thickness design system has not been established yet. In porous pavement system. rainwater penetrates to the subgrade through porous pavements layers. Porous pavements are expected to reduce or alleviate the problems caused by impermeable pavement layer such as flood damage due to heavy rain in the city, drainage load, disorder in ecosystem, and heat island. However, its structural design methods in traffic roads has not been made mainly because of not being able to consider adequately the effect of rainwater on subgrade strength. In this study, structural design method of porous pavements is suggested after considering the subgrade weakness due to rainwater and numerical mechanical analysis. It is noted that elastic modulus of subgrade is reduced by 20% as subgrade moisture content is increased by 2% at optimum moisture content in the literature review. As a result of both finite element analysis and strength loss of subgrade by the existing design method, it is necessary to increase subbase thickness about 30cm in porous pavements compared with the existing traffic road pavement system. It is similar to premium thickness of structural design of porous pavements in Japan.

• Journal of Korean Society of Transportation
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• v.32 no.1
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• pp.27-38
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• 2014

Recently, urban and transportation planning for Transit Oriented Development(TOD) has become a major issue. For the effective policy implementation of TOD, it is important to understand the travel behavior of residents in housing areas. In this study, we compared the travel behaviors of residents by housing types based on 'the 2010 Household Travel Survey Data' focusing on metropolitan areas. By building an estimation model for subway trip frequency by housing types, it was identified that the factors influencing subway trips and ultimately suggested implications to increase the use of the subway. The highest share of bus mode was for detached house residents with 22.8%, whereas the share of subway mode was highest by efficiency apartment residents with 17.5%. Walking distance to the subway from efficiency apartment and row house were verified as 661meters and 749meters. As the residents of each housing type have more cars and bicycles, their subway trips were decreased. It was also found that subway trips were increased when the population density of residence was high with good accessibility to subway stations and poor accessibility to bus service. In this study, the statistical findings to differentiate the planning factors of public transportation by housing types were also provided. The results of this study would be used for urban design considering the travel behaviors of residents by housing types and can also be utilized for promoting the patronage of public transportation. Some limitations and a future research agenda have also been discussed.