• Journal of Information Processing Systems
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• v.11 no.2
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• pp.205-228
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• 2015

In this paper, we present a virtual laboratory platform (VLP) baptized Mercury allowing students to make practical work (PW) on different aspects of mobile wireless sensor networks (WSNs). Our choice of WSNs is motivated mainly by the use of real experiments needed in most courses about WSNs. These experiments require an expensive investment and a lot of nodes in the classroom. To illustrate our study, we propose a course related to energy efficient and safe weighted clustering algorithm. This algorithm which is coupled with suitable routing protocols, aims to maintain stable clustering structure, to prevent most routing attacks on sensor networks, to guaranty energy saving in order to extend the lifespan of the network. It also offers a better performance in terms of the number of re-affiliations. The platform presented here aims at showing the feasibility, the flexibility and the reduced cost of such a realization. We demonstrate the performance of the proposed algorithms that contribute to the familiarization of the learners in the field of WSNs.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.182-189
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• 2012

This study suggests a dynamic design process for deciding properly design parameters of a mass-spring type Wave Energy Converter (WEC) to achieve sufficient energy conversion from wave to power generator. The WEC mechanism, in this research, consists of a rigid sprung body, a platform, suspension springs and dampers. The rigid sprung body is supported on the platform via springs and dampers and vibrates translationally in the heave direction under wave excitation. At last the resulting heave motion of the sprung body is transmitted to rotating motion of the electric generator by rack and pinion, and transmission gears. For the purpose of vibration analysis, the WEC mechanism has been simply modelled as a mass-spring-damper system under harmonic base excitation. Its maximum displacement transmissibility and steady state response can be determined by using elementary vibration theory if the harmonic ocean wave data were provided. With the vibration analysis results, the suggested dynamic design process of WEC can determine all the design parameters of the WEC mechanism, such as sprung body mass, suspension spring constant, and damping coefficient that can give sufficient relative displacement transmissibility and the associated inertia moment to drive the electric generator and transmission gears.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.1-8
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• 2012

The purpose of this study were to evaluate the dynamic characteristics of the portable slipmeters with respect to actual slipping and to compare their output with those of force platform. The selected slipmeters were commonly used devices for slipperiness measurement in situ floors. Their output quantity represented force (BOT-3000), loss of energy(British pendulum striker) and angle of inclination(English XL). The validity of these devices was studied with respect to actual slipping using a force platform. The precision of these devices was also evaluated with force platform. Based on dynamics of human subject behavior when slipping during normal walking, the all devices tested in this study showed poor performances: low built up ratio, low normal pressure, and long contact time prior to slip. Nevertheless, their results reasonably correlated with those calculated from the ground reaction forces generated by the operation of the selected slipmeters on the force platform although the absolute values of COF from these three devices could be quite different. Also the results showed good repeatability under the some test conditions.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.237-240
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• 2003

This paper reports the characteristics of TFTs, formed inside a location-controlled grain: "single-crystalline" Si TFTs (c-Si TFTs). Position of the grains were controlled with a great precision by "${\mu}-Czochralski$ (grain-filter) process". Effects of process parameters, such as, deposition method of gate $SiO_2$, crystallization energy density and position of the channel with respect to the grain filters on TFT characteristics is investigated. It is concluded that the characteristics of TFTs drastically improved by avoiding the grain filter from the channel region. With TFTs having the current-flow direction parallel to radial direction from the grain-filter, electron mobility and subthreshold swing of 600 $cm^2/Vs$ and 0.21 V/dec. respectively are obtained.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1067-1072
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• 2014

The ability to overcome obstacles is necessary for field robots for various applications including the ability to climb stairs. While much research has been performed focusing on overcoming obstacles, the resulting robots do not have sufficient ability to overcome obstacles such as stairs. In this research, the purpose is to overcome relatively large obstacles by flipping locomotion through the modification of the stair climbing robotic platform of the previous research. We propose two scenarios to overcome large obstacles: a rear wheel driving system and an elevation system using a ball screw. The research is performed based on static analyses on obstacle-climbing. As the simulation results indicate, we determined the optimal posture of the robot for climbing obstacles for rear wheel driving. Also, an elevation system is analyzed for obstacle climbing. Between the two scenarios an elevation system is determined to reduce the operating torque of the actuator, and the prototype was recently assembled. The climbing ability of the robotic platform is verified. We expect the application area for this robotic platform will be in accident areas of nuclear power plants.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.654-661
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• 2015

Stairs are the most popular obstacles in buildings and factories. To enlarge the application areas of a field robotic platform, stair-climbing is very important mission. One important reason why a stair-climbing is difficult is that stairs are various in sizes. To achieve autonomous climbing of various-sized stairs, dynamic modeling is essential. In this research, an inverse dynamic modeling is performed to enable an autonomous stair climbing. Stair-climbing robotic platform with flip locomotion, named FilpBot, is analyzed. The FlipBot platform has advantages of robust stair-climbing of various sizes with constant speed, but the autonomous operation is not yet capable. Based on external constraints and the postures of the robot, inverse dynamic models are derived. The models are switched by the constraints and postures to analyze the continuous motion during stair-climbing. The constraints are changed according to the stair size, therefore the analysis results are different each other. The results of the inverse dynamic modeling are going to be used in motor design and autonomous control of the robotic platform.

• Geomechanics and Engineering
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• v.37 no.3
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• pp.279-291
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• 2024

The "Korea Institute of Geoscience and Mineral (KIGAM) Quake" is a web-based open platform developed for publicly serving seismological data from 61 stations operated by KIGAM in Korea. The service provides meta-information related to observatory sites, sensors, and recorders necessary for utilizing the seismological data, as well as mainly observed continuous and strong-motion waveforms. The data is available through both the web and International Federation of Digital Seismograph Networks (FDSN) web services (open API), a unified data-providing interface in seismology. The platform aims to strengthen its open nature by offering a signal processing function for strong ground motions that can be controlled by user requests. The processed results can be downloaded in ASCII format, designed to meet the increased demands and accessibility in the earthquake engineering field. The platform also offers earthquake research information produced by KIGAM, such as recent major earthquake source information and academic annual report of earthquakes. Additionally, a site flat file was constructed for the geotechnical characteristics of 61 KIGAM station (KGNET) sites based on direct investigations and estimations.

• International journal of advanced smart convergence
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• v.9 no.2
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• pp.8-19
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• 2020

We see an energy fucused smart city evolution of the UK along with the project of "Smart London Plan (SLP)." A theoretical logic of business model innovation has been discussed and a research framework of evolving energy focused smart city is formulated. The starting point is the silo system. In the second stage, the private investment in smart meters establishes a basement for next stages. As results, the UK's smart energy sector has evolved from smart meter installation through smart grid to new business models such as water-energy nexus and microgrid. Before smart meter installation of the government, the electricity system was centralized. However, after consumer engagement plan has been set to make them understand benefits that they can secure through smart meters, the customer behavior has been changed. The data analytics firm enables greater understanding of consumer behavior and it helps energy industry to be smart via controlling, securing and using that data to improve the energy system. In the third stage, distribution network operators (DNOs)' access to smart meter data has been allowed and the segmentation starts. In the fourth stage, with collaboration of Ofwat and Ofgem, it is possible to eliminate unnecessary duplication of works and reduce interest conflict between water and electricity. In the fifth stage, smart meter and grid has been integrated as an "adaptive" system and a transition from DNO to DSO is accomplished for the integrated operation. Microgrid is a prototype for an "adaptive" smart grid. Previous steps enable London to accomplish a platform leadership to support the increasing electrification of the heating and transport sector and smart home.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.61-64
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• 2003

The information display industry this century has to improve our life without increasing energy consumption. Suftla technology together with high-performance silicon thin film transistors (TFTs) and ink-jet technology for forming metal-wiring and organic TFTs will play leading roles for achieving this requirement. In this paper these technologies are reviewed and the concept of the information displays in near future is discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.611-618
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• 2020

The reliability of the results of LCC analysis is determined by accurate analytical procedures and energy data from which the uncertainty is removed. Until now, systems that can automatically measure these energy data and produce databases have not been commercialized. Therefore this paper proposes a concept model of an S-LCC platform that can automatically collect and analyze electric energy consumption data of equipment systems using the IOT, which is the core tool in the Fourth Industrial Revolution and operates the equipment system efficiently using the analyzed results. The proposed concept model was developed by the convergence of existing BLCS and IOT and was comprised of five modules: Facility Control Module, LCC Analysis Module, Energy Consumption Control Module, Efficiency Analysis Module, and Maintenance Standard Reestablishment Module. Using the results of LCC analysis deduced from this system, the deterioration condition of an equipment system can be identified in real-time. The results can be used as the baseline data to re-establish standards for the maintenance factor, replacement frequency, and lifetime of existing equipment, and establish new maintenance standards for new equipment. If the S-LCC platform is established, it would increase the reliability of LCC analysis, reduce the labor force for entering data and improve accuracy, and would also change disregarded data into big data with high potential.