• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.573-579
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• 2006

Most of the recently developed robots are human friendly robots which imitate an animal or human such as entertainment robot, biomimetic robot and humanoid robot. Interest in these robots is increased because the social trend is focused on health, welfare, and graying. By these social backgrounds, robots become more human friendly and suitable or home or personal environment. The more biomimetic robots resemble living creature, the more human feels familiarity. Human feels close friendship not only when feeding a pet, but also when watching a pet having the food. Most of entertainment robots and pet robots use internal-type batteries and have a self-recharging function. Entertainment robots and pet robots with internal-type batteries are not able to operate during charging the battery. So far there have been a few robots that do not depend on an internal battery. However, they need a bulky energy conversion unit and a slug or foods as an energy source, which is not suitable for home or personal application. In this paper, we introduce a new biomimetic entertainment robot with autonomous eating functionality, called EPRO-1(Eating Pet RObot version 1). The EPRO-1 is able to eat a food (a small battery), by itself and evacuate. We describe the design concept of the autonomous eating mechanism of the EPRO-1, characteristics of sub-parts of the manufactured mechanism and its control system.

• Smart Structures and Systems
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• 제24권4호
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• pp.553-566
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• 2019

This study aimed to categorize pervious rubberized concrete into fresh and hardened concrete analyzing its durability, permeability and strength. During the globalization of modern life, growing population and industry rate have signified a sustainable approach to all aspects of modern life. In recent years, pervious concrete (porous concrete) has significantly substituted for pavements due to its mechanical and environmental properties. On the other hand, scrap rubber tire has been also contributed with several disposal challenges. Considering the huge amount of annually tire wastes tossing out, the conditions become worse. Pervious concrete (PC) gap has graded surface assisted with storm water management, recharging groundwater sources and alleviate water run-offs. The results have shown that the use of waste tires as aggregate built into pervious concrete has tremendously reduced the scrap tire wastes enhancing environmental compliance.

• Environmental Engineering Research
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• 제24권2호
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• pp.279-288
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• 2019

To obtain insightful knowledge of geochemical process controlling fluoride enrichment in groundwater of the villages near Shilabati river bank, West Bengal, India, multivariate statistical techniques were applied to a subgroup of the dataset generated from major ion analysis of groundwater samples. Water quality analysis of major ion chemistry revealed elevated levels of fluoride concentration in groundwater. Factor analysis (FA) of fifteen hydrochemical parameters demonstrated that fluoride occurrence was due to the weathering and dissolution of fluoride-bearing minerals in the aquifer. A strong positive loading (> 0.75) of fluoride with pH and bicarbonate for FA indicates an alkaline dominated environment responsible for leaching of fluoride from the source material. Mineralogical analysis of soli sediment exhibits the presence of fluoride-bearing minerals in underground geology. Hierarchical cluster analysis (HCA) was carried out to isolate the sampling sites according to groundwater quality. With HCA the sampling sites were isolated into three clusters. The occurrence of abundant fluoride in the higher elevated area of the observed three different clusters revealed that there was more contact opportunity of recharging water with the minerals present in the aquifer during infiltration through the vadose zone.

• 한국비블리아학회지
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• 제29권4호
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• pp.227-249
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• 2018

본 연구는 사서교사에게 직무소진이 발생하는 요인 및 상황을 파악하기 위한 연구이다. 이를 위하여 고등학교 도서관에서 근무하고 있는 15명의 사서교사를 대상으로 심층 인터뷰를 실시하였다. 본 연구의 결과, 사서교사의 직무환경, 사서교사의 역할 및 정체성의 문제, 학교공동체 구성원들의 학교도서관 및 사서교사에 대한 인식 등이 직무소진의 영향 요인으로 밝혀졌으며, 이를 해결하기 위한 방안으로는 사서교사들에 대한 적절한 보상 체계의 마련, 사서와 사서교사간의 명확한 직무 구분, 학교공동체 구성원들의 사서교사에 대한 인식 전환을 위한 계기 및 제도적 장치의 마련, 사서교사의 자기계발 및 재충전의 기회 제공 등이 필요함을 제시하였다.

• 센서학회지
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• 제28권1호
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• pp.64-70
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• 2019

Wireless sensors have been developed in numerous ways for enhancing the convenience of installation, management and maintenance of sensors. Energy harvesting wireless sensors, which can collect energy from the external environment for permanent usage without the need of recharging and exchanging batteries, have been developed and employed used in Internet of Things and at various industrial sites. Energy harvesting wireless sensors are significantly affected by the sensor lifespan to sudden variation in the external environment. Furthermore, reduction in the sensor operating timespan can greatly affect the characteristics of the devices connected through a network. In this paper, a system performance index is proposed that can comprehensively evaluate the lifespan of a solar cell wireless sensor, determine the characteristics of devices connected to the associated network, and recommend dynamic power distribution control for improving the system performance index. Improvement in the system performance index was verified by applying the proposed dynamic power distribution control to an air conditioner network system using a solar cell wireless sensor. Obtained results corroborate that the dynamic power distribution control can extend the lifespan of the incorporated wireless sensor and reduce the air conditioner's power consumption.

• ETRI Journal
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• 제44권3호
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• pp.389-399
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• 2022

Wireless sensor networks (WSNs) are one of the basic building blocks of Internet of Things (IoT) systems. However, the wireless sensing nodes in WSNs suffer from energy constraint issues because the replacement/recharging of the batteries of the nodes tends to be difficult. Furthermore, a number of realistic IoT scenarios, such as habitat and battlefield monitoring, contain mobile sensing elements, which makes the energy issues more critical. This research paper focuses on realistic WSN scenarios that involve mobile sensing elements with the aim of mitigating the attendant energy constraint issues using the concept of radio-frequency (RF) energy extraction. The proposed technique incorporates a cluster head election workflow for WSNs that includes mobile sensing elements capable of RF energy harvesting. The extensive simulation analysis demonstrated the higher efficacy of the proposed technique compared with the existing techniques in terms of residual energy, number of functional nodes, and network lifetime, with approximately 50% of the nodes found to be functional at the 4000th, 5000th, and 6000th rounds for the proposed technique with initial energies of 0.25, 0.5 and 1 J, respectively.

• 한국포장학회지
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• 제28권3호
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• pp.193-199
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• 2022

Sustainable energy supplies without the recharging and replacement of charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. The TENG harvests electrical energy from wasted mechanical energy in the ambient environment. TENG devices are very likely to be used in next-generation renewable energy and energy harvesting. TENG devices have the advantage of being able to manufacture very simple power devices. In this experiment, various organic dielectrics and inorganic dielectrics were used to improve the open voltage of TENG, Among the various organic dielectrics, Teflon-based FEP, which has the highest electron affinity, showed the highest open voltage and Al electrode was fabricated on Teflon substrate by sputtering deposition process. And AAO (Anodized Aluminum Oxide) nanostructures were applied to maximize the specific surface area of the TENG device. The power generation of TENG within the acceleration level (0.25, 0.5, 1.0, 1.5 and 2 G) and the frequency range (5-120 Hz) of the domestic transport environment was up to 4 V.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.937-944
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• 2022

Electric vehicles (EVs) have been growing to reduce energy consumption and greenhouse gas (GHG) emissions in the transportation sector. The increasing number of EVs requires adequate recharging infrastructure, and at the same time, adopts low- or zero-emission electricity production because the GHG emissions are highly dependent on primary sources of electricity production. Although previous research has studied solar photovoltaic (PV) -integrated EV charging stations, it is challenging to optimize spatial areas between where the charging stations are required and where the renewable energy sources (i.e., solar photovoltaic (PV)) are accessible. Therefore, the primary objective of this research is to support decisions of siting EV charging stations using a spatial data clustering method integrated with Geographic Information System (GIS). This research explores spatial relationships of PV power outputs (i.e., supply) and traffic flow (i.e., demand) and tests a community in the state of Indiana, USA for optimal sitting of EV charging stations. Under the assumption that EV charging stations should be placed where the potential electricity production and traffic flow are high to match supply and demand, this research identified three areas for installing EV charging stations powered by rooftop PV in the study area. The proposed strategies will drive the transition of existing energy infrastructure into decentralized power systems. This research will ultimately contribute to enhancing economic efficiency and environmental sustainability by enabling significant reductions in electricity distribution loss and GHG emissions driven by transportation energy.

• 한국멀티미디어학회논문지
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• 제18권5호
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• pp.652-662
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• 2015

It is necessary to develop small, implantable bio-telemetry systems which can measure and transmit patients' bio-signals from internal body to external receiver. When measuring bio-signals, like electrical bio-signals, acoustic bio-signal measurement has also a big clinical usefulness. But, sound signal has larger frequency bandwidth than any other bio-signals. When considering these issues, a wireless telemetry system which has rapid data transmission rate proportional to wide frequency bandwidth is necessary to be developed. The bluetooth module is used to overcome the data rate limitation caused by the large frequency bandwidth. In this paper, a novel multimedia bluetooth biotelemetry system was developed which consists of transmitter module located in the body and receiver device located outside of the body. The transmitter consists of microphone, bluetooth, and wireless charging device. And the receiver consists of bluetooth and codec system. The sound inside the skin is captured by microphone and sent to receiver by bluetooth while charging. The wireless charging system constantly supplies the electric power to the system. To verify the performance of the developed system, an in vitro experiment has been performed. The results show that the proposed biotelemetry system has ability to acquire the sound signals under the skin.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1525-1529
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• 2004

Most of the recently developed robots are human friendly robots which imitate an animal or human such as entertainment robot, bio-mimetic robot and humanoid robot. Interest in these robots are increasing since the social trend is focused on health, welfare, and graying. By these social backgrounds, robots become more human friendly and suitable for home or personal environment. The more bio-mimetic robots resemble living creature, the more human feels familiarity. People feel close friendship not only when they feed a pet, but also when they watch a pet having the food. Most of entertainment robots and pet robots use internal-type batteries and have a self-recharging function. Entertainment robots and pet robots with internal-type batteries are not able to operate during charging the battery. So far there have been a few robots that do not depend on a battery. However, they need a bulky energy conversion unit and a slug or foods as an energy source, which is not suitable for home or personal application. In this paper, we introduce a new bio-mimetic entertainment robot with autonomous feeding functionality, called ELIRO-1(Eating LIzard RObot version 1). The ELIRO-1 is able to find a food (a small battery), feed by itself and evacuate. We describe the design concept of the autonomous feeding mechanism of the ELIRO-1, characteristics of sub-parts of the manufactured mechanism and the control system.