• Journal of Advanced Navigation Technology
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• v.27 no.3
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• pp.287-292
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• 2023

In the case of fixed CCTV, there is a problem in that a shadow area occurs, even if the visible range is maximized by utilizing the pan-tilt and zoom functions. The representative solution for that problem is that a plurality of fixed CCTVs are used. This requires a large amount of additional equipment (e.g., wires, facilities, monitors, etc.) proportional to the number of the CCTVs. Another solution is to use drones that are equipped with cameras and fly. However, Drone's operation time is much short. In order to extend the time, we can use multiple drones and can fly one by one. In this case, drones that need to recharge their batteries re-enter into a ready state at the drone port for next operation. In this paper, we propose a system for precised positioning and stable landing on the drone port by utilizing a small drone equipped with a fixed forward-facing monocular camera. For our conclusion, we implement our proposed system, operate, and finally verify our feasibility.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.305-318
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• 2022

We focused on the care effectiveness of the interactive AI robots. developed an AI toy robot called 'Agaya' to contribute to personalization with more human-centered care. First, by applying P-TTS technology, you can maximize intimacy by autonomously selecting the voice of the person you want to hear. Second, it is possible to heal in your own way with good memory storage and bring back memory function. Third, by having five senses of the role of eyes, nose, mouth, ears, and hands, seeking better personalised services. Fourth, it attempted to develop technologies such as warm temperature maintenance, aroma, sterilization and fine dust removal, convenient charging method. These skills will expand the effective use of interactive robots by elderly people and contribute to building a positive image of the elderly who can plan the remaining old age productively and independently

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.547-558
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• 2023

This research delves into the fabrication of an ultra-high-strength concrete, enriched with oxidized graphene nanoplatelet(GO) and hollow glass powder(HGP), notably eschewing the conventional inclusion of silica fume(SF). The primary objective was to scrutinize the autogenous shrinkage characteristics of this innovative formulation. It was discerned that the NewMix specimen, which incorporated the cGO(sourced from Company C) and HGP, and intentionally bypassed SF, showcased a commendable 13% reduction in autogenous shrinkage relative to the benchmark(Ref) specimenthat incorporated SF. Moreover, the proclivity for crack formation owing to autogenous shrinkage in the NewMix was observed to manifested by NewMix at the juncture of cracking emerged as the apex value. Attributed to the expansive specific surface area and exemplary dispersibility of cGO, it was postulated that the concrete's pore structure benefitted from enhanced infill, leading to a reduction in autogenous shrinkage. Additionally, the cGO integration fortified the concrete's resistance to crack initiation. Consequently, such an enhancement is posied to be pivotal in mitigating crack propagation resulting from autogenous shrinkage in ultra-high-strength concrete.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.50-60
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• 2009

Recently, the traffic card is gradually utilized and its several supplementary services have been significantly developed. Particularly, since it is possible to pay fees for buses, taxies, subways, parking and tollgates with only one traffic card, new payment method for economically processing has been focused. This paper presents a new receipt management system which allows possibly paying with several digital cards through PC interfacing terminals. The proposed system is mainly composed of three parts: terminals, middleware, and management servers. A terminal part includes processing module for payment/charging and credit/check/debit cards, etc and its operation is fulfilled through a middleware part. A main task of a middleware part is to connect a terminal part to managing servers through middleware applications. Additionally, processing of several receipt items and monitoring of the terminals to product statistical reports based on the processed result are carried out in the middleware. A management sever part is accomplished for collecting all of transaction histories against users and charging items over allowed province and managing statistical information. The proposed system is currently utilized in the Nam-GU district office and the Nam-GU district health center, Busan, S. Korea, respectively for testing its effectiveness. We conclude from this demonstration that the system is more useful and efficient than the previous processing method especially in that variable payment ways are provided and consumption burden is reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.703-710
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• 2017

Third-generation (3G) devicesare next-generation devices that allow the use of intelligent services and applications through the Internet of Things (IoT). As the market forexisting smart devices like smartphones and tablet PCs enters the stage of stagnation, the world is now focusing on 3G devices, parts, and services. This study is intended to measure the user's benefits from the various attributes of 3G devices by applying an economic valuation method. For this purpose, the conjoint analysis method was applied, which is one of the representative valuation methods. To apply conjoint analysis, the following attributes of 3G devicesare considered: mode of use, power efficiency, life care, and price. By applying the mixed logit model, the marginal willingness-to-pay(WTP) for each attribute was derived. The results are statistically significant. Respondents showed a high preference or complete flexibility in the mode of use attribute. And they were also found to have WTP for improvements in the life care attribute. The implications and quantitative results of this study are expected to be useful for policies and strategies in the 3G device market.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.604-610
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• 2005

This study was to evaluate the effects of several light curing units on the microleakage of composite resin restorations in primary teeth. The types of curing units were traditional low intensity halogen light(Optilux 360), plasma arc light(Filpo) low heat plasma arc light(Aurys) and high intensity LED(Freelight 2). After preparing cavities on sound primary teeth, cavities were filled with composite resin(Z100) using the same resin bond agent(Scotchbond Multi-Purpose) and were cured with each curing light system. After storing each specimen in sterile water for 24 hours, thermal circulation was done 1,000 times followed by pigmentation using 2% methylene blue solution. Each specimen was sliced and the degree of pigmentation was graded. When microleakage is graded, the average of Aurys was 0.95 which was the lowest and Freelight 2(1.05), Filpo(1.25), Optilux 360(1.30) followed. But values were not shown statistically significant difference (P>0.05). The results suggest that the newly developed curing units which has advantage in children by decreasing discomfort and procedure time can increase the microleakage of the composite resin.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.273-281
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• 2019

The energy consumed by buildings among the total national energy consumption is more than 10% of the total. For this reason, Korea has adopted the zero energy building policy since 2025, and research on the energy saving technology of buildings has been demanded. Analysis of buildings' energy consumption patterns shows that lighting, heating and cooling energy account for more than 60% of total energy consumption, which is directly related to solar power acquisition and window opening and closing operation. In this paper, we have developed a low - power IoT sensor module for window system to transfer acquired information to building energy management system. This module transmits the external environment and window opening / closing status information to the building energy management system in real time, and constructs the network to actively take energy saving measures. The power used in the module is designed as an independent power source using solar power among the harvest energy. The topology of the power supply is a Buck converter, which is charged at 4V to the lithium ion battery through MPPT control, and the efficiency is about 85.87%. Communication is configured to be able to transmit in real time by applying WiFi. In order to reduce the power consumption of the module, we analyzed the hardware and software aspects and implemented a low power IoT sensor module.

• Environmental and Resource Economics Review
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• v.30 no.2
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• pp.237-268
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• 2021

As variable renewable sources rapidly increase due to the Energy Transition plan, integration cost of renewable sources to the power system is rising sharply. The increase in variable renewable energy reduces the capacity factor of existing traditional power capacity, and this undermines the efficiency of the overall power supply, and demand resources are drawing attention as a solution. In this study, we analyzed how much electric vehicle demand resouces, which has great potential among other demand resources, can reduce power supply costs if it is used as a flexible resource for renewable generation. As a methodology, a stochastic form of power system optimization model that can effectively reflect the volatile characteristics of renewable generation is used to analyze the cost induced by renewable energy and the benefits offered by electric vehicle demand resources. The result shows that virtual power plant-based direct control method has higher benefits than the time-of-use tariff, and the higher the proportion of renewable energy is in the power system, the higher the benefits of electric vehicle demand resources are. The net benefit after considering commission fee for aggregators and battery wear-and-tear costs was estimated as 67% to 85% of monthly average fuel cost under virtual power plant with V2G capability, and this shows that a sufficient incentive for market participation can be offered when a rate system is applied in which these net benefits of demand resources are effectively distributed to consumers.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.325-331
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• 2016

In driving at evening or night, we are not able to recognize the speed bump and so stop suddenly. It could result in accidents. And also, we have a restriction of street light installation in farm road because it could be harmful to the crops and driver could not recognize the walking people. It needs to develop the speed bump with light and streetlight to be non harmful to the crops. So, we develop both the speed bump and streetlight with LED which could be non harmful to the crops and be increased recognition of walking people in farm road. For LED lighting power, we use the solar cells, and piezoelectric elements. It has automatic on/off according to power saving rates without illumination sensor. Minimization of circuit elements and design of minimum resisters and low power LED was used for power saving in assuring 3-days.

• Tunnel and Underground Space
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• v.24 no.6
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• pp.405-417
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• 2014

In a high-level waste repository, the gap fill of the engineered barrier is an important component that influences the performance of the buffer and backfill. This paper reviewed the overseas status of R&D on the gap fill used engineered barriers, through which the concept of the gap fill, manufacturing techniques, pellet-molding characteristics, and emplacement techniques were summarized. The concept of a gap fill differs for each country depending on its disposal type and concept. Bentonite has been considered a major material of a gap fill, and clay as an inert filler. Gap fill was used in the form of pellets, granules, or a pellet-granule blend. Pellets are manufactured through one of the following techniques: static compaction, roller compression, or extrusion-cutting. Among these techniques, countries have focused on developing advanced technologies of roller compression and extrusion-cutting techniques for industrial pellet production. The dry density and integrity of the pellet are sensitive to water content, constituent material, manufacturing technique, and pellet size, and are less sensitive to the pressure applied during the manufacturing. For the emplacement of the gap fill, pouring, pouring and tamping, and pouring with vibration techniques were used in the buffer gap of the vertical deposition hole; blowing through the use of shotcrete technology and auger placement and compaction techniques have been used in the gap of horizontal deposition hole and tunnel. However, these emplacement techniques are still technically at the beginning stage, and thus additional research and development are expected to be needed.