• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.18 no.1
• /
• pp.74-82
• /
• 2019

The revolution of industry 4.0 is enabling us to build an intelligent connection society called smart cities. The use of renewable energy in particular solar energy is extremely important for modern society due to the growing power demand in smart cities, but its difficult to monitor and manage in each buildings since need to be deploy low energy sensors and information need to be transfer via wireless sensor network (WSN). The Internet of Things (IoT) / low-power wide-area (LPWA) is an emerging WSN technology, to collect and monitor data about environmental and physical electrical / electronics devices conditions in real time. However, providing power to IoT sensor end devices and other public electrical loads such as street lights, etc is an important challenging role because the sensor are usually battery powered and have a limited life time. In this paper, we proposes an efficient solar energy-based power management scheme for smart city based on IoT technology using LoRa wide-area network (LoRaWAN). This approach facilitates to maintain and prevent errors of solar panel based energy systems. The proposed solution maximizing output the power generated from solar panels system to distribute the power to the load and the grid. In this paper, we proved the efficiency of the proposed system with Simulink based system modeling and real-time emulation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.1
• /
• pp.415-423
• /
• 2021

Citizen participation and Living Lab are attracting interest as one of the major strategies for the success of smart cities. In a Living Lab, citizens, who are the end-users of technology, participate in the search for alternatives to define and solve problems and repeat experiments to verify alternatives in a circular process. The purpose of this research was to present an operating model of a citizen-participating online community platform to improve urban problems, implement and test it, and show its applicability. To this end, an operation model of a citizen-participating online community platform was proposed to improve urban problems. An online platform was designed and implemented to reflect the functions pursued by the operation model. Finally, a pilot test for the function was performed using the Oma Elementary School case located in Ilsan, Goyang-si, Gyeonggi-do. The operating model was designed with the city's pedestrian environment and children. As a result, the sharing and communicating process of urban issues among community members worked appropriately according to the designed intention. The Living Lab coordinator could visualize and view urban issues posted by users on a map based on location information. Visualizing the urban problem as a heat map confirmed that urban problems were concentrated in a specific area.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.24 no.6
• /
• pp.109-119
• /
• 2021

Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. Green roof improves the urban thermal environment and save the cooling energy in buildings. This study presented a green roof combined with a storage system that stores rain-water and supplies water through a wick and evaluated the temperature reduction effect as surface temperature and amount of evapotranspiration. For about a week, the surface temperature using a infrared thermal imager and the evapotranspiration by recording change of module weight were measured at intervals of 30 minutes from sunrise to sunset. The results show that the mean surface temperature of the green roof was 15.4 degrees lower than that of the non-green roof from 12:00 P.M. to 14:00 P.M. There was no significant difference between mean surface temperature of green roof with and without storage system immediately after rain, but more than a week after rain, there was a difference with average of 2.49 degrees and maximum of 4.72 degrees. The difference in daily amount of evapotranspiration was measured to be 1.66 times on average. As drought stress increased over time, the difference in daily amount of evapotranspiration and surface temperature between with/without storage system increased simultaneously. The results of the study show a more excellent cooling effect of green roof combined with the rainwater storage system.

• Journal of the Korean Society of School Health
• /
• v.28 no.3
• /
• pp.200-210
• /
• 2015

Purpose: This study aimed to examine the use of smart phones and their relationship with self-efficacy and academic achievement among students in 5th to 6th grade. Methods: 954 students in $5^{th}$ to $6^{th}$ grade were selected from three elementary schools in K City through purposive sampling. Data of 591 respondents were analyzed by $x^2$ test, ANOVA, correlation analysis and multiple regression analysis using the SPSS/WIN program. Results: First, 64% of the students possessed a smart phone and female students used their phone more than male students. 47.5% of the students said they first used a smartphone in their $5^{th}$ grade and 11.7% said in their 6th grade. Second, heavier use of smart phones was related to a lower level of self-efficacy (p<.001). Third, the more the students used a smart phone, the less they achieved in academic performance (Korean language: p<.001, mathematics: p<.01). Finally, the biggest factor influencing smart phone addiction was longer use of smart phones. In addition, lower self-efficacy and lower ability to adapt to difficult tasks were the factors influencing the increase in smart phone addiction. Less use of smart phones and higher self-efficacy resulted in higher achievement in academic performance. Conclusion: It is essential to decrease students' use of smart phones and improve their self-efficacy and academic performance. Intervention programs to reduce the use of smart phones should include a profound interest, a personality-oriented educational environment and sufficient dialogues with students at home, schools and the local society, beyond simple regulations to prevent adverse effects.

• Journal of Intelligence and Information Systems
• /
• v.14 no.3
• /
• pp.109-131
• /
• 2008

Ubiquitous Smart Space(USS) like u-City has been expected to create a high added value. However, developing USS has a high risk because it should use future technologies and development methodologies that have been never tried in the past. Hence, it has to be considered thoroughly in the very first stage of development. Moreover, USS usually uses several ubiquitous computing technologies combinationally because of the nature of USS. Despite of this, existing technology selection methodologies or technology evaluation methodologies only focus on a single technology. This leads us to develop a methodology of optimal technology combination for developing a specific USS. The purpose of this paper is to propose the methodology and to apply it to develop a real USS. We use portfolio theory and constraint satisfaction problem to determine an optimal technology combination. We also apply our methodology to the national ubiquitous computing project which carries out at present to validate it.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7902-7909
• /
• 2015

The needs for smart city management technology has been increased for efficiently managing huge and complex social infrastructures. Thus, this research introduces smart bridge facility management system based on sensor and BIM technologies so that the inadequacy of current facility maintenance system and the limitations of data objectivity, consistency and expandability can be improved. For which, current trends on sensor and BIM technologies and standard information system were investigated to derive system develop requirements, and a scenario was suggested to discuss how to utilize the suggested system. Research outcomes are expected to be utilized as a preliminary research for developing the real application framework for bridge facility management.

• IEIE Transactions on Smart Processing and Computing
• /
• v.2 no.3
• /
• pp.148-159
• /
• 2013

An analysis of the throughput and stability region of random access systems is currently of interest in research and industry. This study evaluated the performance of a multiuser random access channel with a retransmission gain. The channel was composed of a media access control (MAC) determined by the transmission probabilities and a multiuser communication channel characterized by the packet reception probabilities as functions of the number of packet transmissions and the collision status. The analysis began with an illustrative two-user channel, and was extended to a general multiuser channel. For the two-user channel, a sufficient condition was derived, under which the maximum throughput was achieved with a control-free MAC. For the channel with retransmission gain, the maximum steady throughput was obtained in a closed form. The condition under which the random access channel can acquire retransmission gain was also obtained. The stability region of the general random access channel was derived. These results include those of the well-known orthogonal channel, collision channel and slotted Aloha channel with packet reception as a special instance. The analytical and numerical results showed that exploiting the retransmission gain can increase the throughput significantly and expand the stability region of the random access channel. The analytical results predicted the performance in the simulations quite well.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.1130-1137
• /
• 2022

The Industry Foundation Classes (IFC) provides standardized product models for the building construction domain. However, the current IFC schema has limited representation for infrastructure. Several studies have examined the data schema for road and highway modeling, but not in a sufficiently comprehensive and robust manner to facilitate the overall integrated project delivery of road projects. Several discussions have focused on slope engineering for road projects, but no solution has been provided regarding the formalized parametric modeling up to now. Iterative design, analysis, and modification are observed during the process of slope design for road projects. The practitioners need to carry out the stability analysis to consider different road design alternatives, including horizontal, vertical, and cross-section designs. The procedure is neither formalized nor automated. Thus, there is a need to develop the formal representation of the product and process of slope analysis for road design. The objective of this research is to develop a formal representation (i.e., an IFC extension data schema) for slope analysis. It consists of comprehensive information required for slope analysis in a structured manner. The deliverable of this study contributes to both the formal representation of infrastructure development and, further, the automated process of slope design for road projects.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_2
• /
• pp.799-810
• /
• 2023

This paper analyzed changes in population mobility characteristics based on emergency disaster messages related to wildfires that occurred in 2022, using mobile data. The primary wildfires under analysis are the ones that occurred in Donghae City and Miryang City. Donghae City sent a total of six evacuation messages in response to the wildfire incidents, and all of the message contents specified particular evacuation locations. As a result, it was analyzed that there was a significant impact on changes in population mobility characteristics. On the other hand, in the case of Miryang City, a total of five evacuation messages were sent during the wildfire period, but not all messages specified a clear evacuation location,such as "A safe place". As a result, it was observed that there was minimal change in population mobility due to the lack of clear evacuation locations specified in the messages. These analysis results suggest the need for institutional improvements such as the standardization and specification of emergency alert message content when wildfires or similar disasters occur in different regions.

• Journal of The Korean Association of Information Education
• /
• v.18 no.4
• /
• pp.471-482
• /
• 2014

It is known that the smart education has a positive impact of critical thinking skills and problem solving, communication and collaboration, creativity and innovation in the 21st century. However, some people concern about the adverse effects of smart education such as smart devices addiction and health problems. In this study, we conducted the adverse effects of education using smart devices on students. The questionnaire survey was conducted and analyzed for students in 9 schools at A city(four elementary schools, three middle schools, two high schools) that are receiving smart education. The types of adverse effects of smart education includes smartphone addiction, lack of information ethics, health problems, and lack of social and learning ability. We showed the differences each item compared among elementary school, middle school and high school about adverse effects of smart education. The result of survey didn't have any adverse affect of smart education such as internet addiction or smartphone addiction. However in order to protect the copyright, the school needs to fight against indiscriminated downloads and perform the information ethics education. Plus we surely need to be more open-minded in reading and exercise at school and home.