• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.28-36
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• 2016

Recently, owing to the development of ICT industry and wide spread of smart phone, the number of people who use car sharing service are increased rapidly. Currently two-way car sharing system with same rental and return locations are mainly operated since this system can be easily implemented and maintained. Currently the demand of one-way car sharing service has increase explosively. But this system have several obstacle in operation, especially, vehicle stock imbalance issues which invoke vehicle relocation. Hence in this study, we present an optimization approach to depot location and relocation policy in one-way car sharing systems. At first, we modelled as mixed-integer programming models whose objective is to maximize the profits of a car sharing organization considering all the revenues and costs involved and several constraints of relocation policy. And to solve this problem efficiently, we proposed a new method based on particle swarm optimization, which is one of powerful meta-heuristic method. The practical usefulness of the approach is illustrated with a case study involving satellite cities in Seoul Metrolitan Area including several candidate area where this kind systems have not been installed yet and already operating area. Our proposed approach produced plausible solutions with rapid computational time and a little deviation from optimal solution obtained by CPLEX Optimizer. Also we can find that particle swarm optimization method can be used as efficient method with various constraints. Hence based on this results, we can grasp a clear insight into the impact of depot location and relocation policy schemes on the profitability of such systems.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.4
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• pp.59-66
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• 2015

The rapid development of information communication technology(ICT) is born opportunities of business venturing and many items of start-up. On the smart media era, there are a lot of location based services. Thus we researched to find which factors impact location based constructs on smartphone environment in this study. We have conducted a preference analysis of the influencing factors for location based constructs for our study. In first steps, based constructs that were already known by empirical studies were categorized information, entertainment, safe&emergency, navigation&tracking and advertising&commerce. In second steps, the preference relationship among the categorized constructs were analyzed using AHP(analytic hierarchy process) technique. Participants of this study were 106 students H university in Daejeon-city during 2014. 10. 11 to 2014. 10. 25. The result of the analysis might be summarized that the chatting(0.170) has the highest preference among the above constructs. Based on these findings, several theoretical and practical implications were suggested and discussed.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.261-267
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• 2016

As IoT technology has gained the attention all around the world, the development for various services of healthcare, smart city, agriculture, and defense based on IoT is in progress. However, it is likely that healthcare services based on IoT have a problem of being leaked of patients' biological information by a third party and that risks patients' lives. In this paper, an IoT health care service managing model based on location sensor is proposed, which secures the biological information of a patient and simplifies the procedure to process the treatment and administration steps by using the data resources sensed. Even when an emergency occurs, this proposed model can respond quickly using the location information of the patient, which enables the staff in the hospital to locate the patient in real time. In addition, there is an advantage to minimize the time and the process of care, because the location of the equipment for necessary treatment is possible to be instantaneously located with attached sensors.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.117-129
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• 2009

This paper studied the safety management network system of infrastructure which constructed smart sensors, closed-circuit television(CCTV) and monitoring system. This safety management of infrastructure applied to bridge, cut slop and tunnel, embankment etc. The system applied to technologies of standardization guidelines, data acquirement technologies, data analysis and judgment technologies, system integration setup technology, and IT technologies. It was constructed safety management network system of various infrastructure to improve efficient management and operation for many infrastructure. Integrated safety management network system of infrastructure consisted of the real-time structural health monitoring system of each infrastructure, integrated control center, measured data transmission using i of tet web-based, collecting data using sf ver, early alarm system which the dangerous event of infrastructure occurred. Integrated control center consisted of conference room, control room to manage and analysis the data, server room to present the measured data and to collect the raw data. Early alarm system proposed realization of warning and response within 5 minute or less through development of sensor-based progress report and propagation automation system using the media such as MMS, VMS, EMS, FMS, SMS and web services of report and propagation. Based on this, the most effective u-Infrastructure Safety Management System is expected to be stably established at a less cost, thus making people's life more comfortable. Information obtained from such systems could be useful for maintenance or structural safety evaluation of existing structures, rapid evaluation of conditions of damaged structures after an earthquake, estimation of residual life of structures, repair and retrofitting of structures, maintenance, management or rehabilitation of historical structures.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.53-59
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• 2018

In Korea, The number of installed LPG Charging stations is about 2000, increasing by 26 every year. In these, about 500 charging stations are older above 15 year, accounting about 25% of total stations. About 86% of them are located in the city, which is causing serious damage if accident occurs. In this paper, we developed a duel gas sensor module and integrated control system software that can prevent and correspondence to gas leaks and fire accidents at LPG/CNG charging stations. The dual type sensor module has the function of collecting and transmitting the measured data to the sensors of methane, butane and hydrogen through RF433Mhz communication. In addition, each sensor is attached with two to improve stability and accuracy. The integrated control system software detects real-time data of the devices measured by the sensors and it send to the PC and smart phone of manager. Therefore, if accident occurs, the manager can check the status of the charging station regardless of time and place.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.595-618
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• 2010

This paper describes the application of a wireless sensor network to a 31 meter-tall medieval tower located in the city of Trento, Italy. The effort is motivated by preservation of the integrity of a set of frescoes decorating the room on the second floor, representing one of most important International Gothic artworks in Europe. The specific application demanded development of customized hardware and software. The wireless module selected as the core platform allows reliable wireless communication at low cost with a long service life. Sensors include accelerometers, deformation gauges, and thermometers. A multi-hop data collection protocol was applied in the software to improve the system's flexibility and scalability. The system has been operating since September 2008, and in recent months the data loss ratio was estimated as less than 0.01%. The data acquired so far are in agreement with the prediction resulting a priori from the 3-dimensional FEM. Based on these data a Bayesian updating procedure is employed to real-time estimate the probability of abnormal condition states. This first period of operation demonstrated the stability and reliability of the system, and its ability to recognize any possible occurrence of abnormal conditions that could jeopardize the integrity of the frescos.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1071-1081
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• 2021

Remote Sensing using unmanned aerial vehicles(UAV) can acquire images with higher time resolution and spatial resolution than aerial and satellite remote sensing. However, UAV images are photographed at low altitude and the area covered by one image isrelatively narrow. Therefore multiple images must be processed to monitor large area. Since UAV images are photographed under different exposure conditions, there is difference in brightness values between adjacent images. When images are mosaicked, unnatural seamlines are generated because of the brightness difference. Therefore, in order to generate seamless mosaic image, a radiometric processing for correcting difference in brightness value between images is essential. This paper proposes a relative radiometric calibration and image blending technique. In order to analyze performance of the proposed method, mosaic images of UAV images in agricultural and mountainous areas were generated. As a result, mosaic images with mean brightness difference of 5 and root mean square difference of 7 were avchieved.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.25-31
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• 2021

Moving toward an aged society, traffic accidents involving elderly drivers have also attracted broader public attention. A rapid increase of senior involvement in crashes calls for developing appropriate crash-severity prediction models specific to senior drivers. In that regard, this study leverages machine learning (ML) algorithms so as to predict the severity of vehicle-pedestrian collisions induced by elderly drivers. Specifically, four ML algorithms (i.e., Logistic model, K-nearest Neighbor (KNN), Random Forest (RF), and Support Vector Machine (SVM)) have been developed and compared. Our results show that Logistic model and SVM have outperformed their rivals in terms of the overall prediction accuracy, while precision measure exhibits in favor of RF. We also clarify that driver education and technology development would be effective countermeasures against severity risks of senior driver-induced collisions. These allow us to support informed decision making for policymakers to enhance public safety.

• Journal of Family Relations
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• v.22 no.2
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• pp.71-97
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• 2017

Objectives: The purpose of this research was to analyze the influence of self-actualization needs, dependence on parents, and work-family balance stress affecting on the marriage friendly attitudes among the unmarried women in twenties and thirties. Method: The participants were 315 unmarried women connected by SNS. The data were collected by questionnaire method through SNS by the smart phone using by the snowball sampling method and analyzed by t-test, ANOVA, and hierarchical multiple regression analysis. Results: First, there were significant differences in the marriage friendly attitudes according to education level, religion, dating. In the case of college graduates, having religion and dating partner, unmarried women had more marriage friendly attitudes. Second, the results of multiple regression showed that the marriage friendly attitudes among unmarried women was significantly influenced by education, religion, and the humanity factor among the self-actualization needs, emotional dependence on parents and work-family balance stress. In addition, the humanity factor among the self-actualization needs was found to be the most influential factor on the marriage friendly attitudes among unmarried women in this study. Conclusion: This study suggests the importance of emphasizing humanity education, having the emotional close relationship with the parents, and enforcing social systems for work-family balance for the greater marriage friendly attitudes of unmarried women in twenties and thirties.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.5-22
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• 2021

Digital Twin for Land(DTL) is one of the national work projects in the Korean New Deal but there aren't still any standards and technical guides which would need to construct the DTL. This study presents the policies to develop reference model and data model based on geo-spatial information standards to ensure interoperability for the DTL. In this paper, we first extract the implications through reviewing definitions of Digital Twin used in various literatures and international standardization trends on Digital Twin. In addition, this study attempts to conceptualize the DTL through various ways such as defining the DTL and characterizing DTL domains. Finally, we propose three policies on the standardization of the DTS: (1) DTS reference model by using RM-ODP, (2) three-steps hierarchical data models, and (3) model registry to manage the data models efficiently. The proposed policies of the study would contribute to establish a way for DTS's standards development over the coming years.