• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.77-84
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• 2023

In the agricultural sector, power sources are being developed that use alternative energy sources such as electric tractors and hydrogen tractors, away from internal combustion engine tractors. As parts such as engines and transmissions used in conventional internal combustion engine tractors are replaced with motors and batteries, the center of gravity changes, and thus the risk of rollover should be considered. The purpose of this study is to analyze the overturn angle of the main parts of the electric tractor through dynamic simulation to minimize the overturn accident and to derive the optimal arrangement of parts to improve stability. A total of nine dynamics simulations were conducted by designing three components of the PTO motor, drive motor and the battery pack, and three factors of the arrangement method. As a result of the experiment, it was confirmed that Type3 Level3, in which the drive motor and the PTO motor are located at the front and rear of the tractor, and two battery packs are located in the middle of the tractor, has a high rollover angle. As a result of this study, the stability increased as the center of gravity was placed backward and located below. Future research needs to be done to find the optimal location of parts considering their performance and placement efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.544-551
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• 2011

This paper presents the circuit arrangement and effective control method of regenerative energy storage system for an electric vehicle using super-capacitors as the braking energy storage element. A bi-directional controlled current flow of the DC-DC converters with the capacitor bank is connected in parallel with battery, and is controlled so that the whole of the braking energy is effectively absorbed into the capacitors and released back to the electric motor upon acceleration. The converter needs the series-parallel switching circuit for making the best use of the series capacitors and for limiting the step-up ratio of the boost converter. The proposed methods are verified by computer simulation and experimental set-up. They are usefully applied to the electric vehicles such as green cars, electric motorcycles, bike, etc which are power- supplied by the electric batteries.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.86-92
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• 2016

Recently, solar module is installed in crowded areas to offers services so that people can charge their smartphones or tablets. However, the burden in terms of cost is high to install in areas where utilization ratio is low and installation is difficult in limited spaces. In this paper, a system for collecting and providing the optical power is proposed from the analysis about the person that receives service in each area using the real-time data provided by the state and collected from the actual environment as well as considering the waiting time and the solar charging time in different environments. As a result, This study shows that charge was not delayed since collecting power exceeds charging power. Smartphone was fully charged in ninety-five minutes. we confirmed that with one smartphone, it can be charged a approximately fifty percent of the battery in between ten to twenty minutes, with multiple units they can be charged a approximately twenty percent of the battery in between ten to twenty minutes.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.37.2-37.2
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• 2010

Recently $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ has been consistently examined and investigated by scientists because of its high lithium storage capacity, which exceeds beyond the conventional theoretical capacity based on conventional chemical concepts. Consequently, $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ is considered as one of the most promising cathode candidates for next generation in Li rechargeable batteries. Yet the mechanism and the origin of the overcapacity have not been clarified. Previously, many authors have demonstrated simultaneous oxygen evolution during the first delithiation. However, it may only explain the high capacity of the first charge process, and not of the subsequent cycles. In this work, we report a clarified interpretation of the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$, which is the key element in understanding its anomalously high capacity. We identify how the structural evolution of $Li_{1.2}Ni_{0.2}Mn_{0.6}O_2$ occurs upon the electrochemical cycling through careful study of electrochemical profiles, ex-situ X-ray diffraction (XRD), HR-TEM, Raman spectroscopy, and first principles calculation. Moreover, we successfully separated the structural change at subsequent cycles (mainly cation rearrangement) from the first charge process (mainly oxygen evolution with Li extraction) by intentionally synthesizing sample with large particle size. Consequently, the intermediate states of structural evolution could be well resolved. All observations made through various tools lead to the result that spinel-like cation arrangement and lithium environment are created and embedded in layered framework during repeated electrochemical cycling.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1511-1518
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• 2017

Renewable energy hybrid systems look into the process of choosing the finest arrangement of components and their sizing with suitable operation approach to deliver effective, consistent and cost effective energy source. This paper presents hybrid renewable energy system (HRES) solar photovoltaic, downdraft biomass gasifier, and fuel cell based generation system. HRES electrical power to supply the electrical load demand of academic research building sited in $23^{\circ}12^{\prime}N$ latitude and $77^{\circ}24^{\prime}E$ longitude, India. Fuzzy logic programming discover the most effective capital and replacement value on components of HRES. The cause regarding fuzzy logic rule usage on HOMER pro (Hybrid optimization model for multiple energy resources) software program finds the optimum performance of HRES. HRES is designed as well as simulated to average energy demand 56.52 kWh/day with a peak energy demand 4.4 kW. The results shows the fuel cell and battery bank are the most significant modules of the HRES to meet load demand at late night and early morning hours. The total power generation of HRES is 23,794 kWh/year to the supply of the load demand is 20,631 kWh/year with 0% capacity shortage.

• Journal of architectural history
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• v.22 no.5
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• pp.37-46
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• 2013

This paper aims to examine the constructional background and process of the Japanese military installations of Jisim-do, especially based on the military secret documents. Furthermore, it aims to analyze the characteristics of the remains. First, the study looked into the procedure of forcible occupation by Japan, involving the background of the designation and forcible accommodation of military reservations, and forced eviction by the purchase of land. Second, the study identified the background of construction, purpose, and construction period of each battery built throughout the 'Fort maintenance period' according to changes in international situations. Third, it is the 'Chukseongbu' that supervised the construction of fortresses. Fourth, the study considered a series of arrangement processes in which Jisim-do became a fortresses through "Yukgunsungdae-ilgi", a military operations report for the Japanese army. Through this, it discovered a clear construction process, construction details, and the supply for Jisim-do. The study was also able to reveal the meticulousness in constructing firm facilities more promptly from the 'design tactics'.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.8
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• pp.696-703
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• 2005

Since most autonomous mobile robots are powered by a battery, it is important to increase the continuous operating time without recharging. This can be achieved by improving the energy efficiency of a mobile robot, but little research on energy efficiency has been performed. This paper proposes two methods for improving the energy efficiency of an omnidirectional mobile robot.. One method is to realize a continuously variable transmission (CVT) by adopting the mechanism of steerable omnidirectional wheels. The other is the proposed steering algorithm in which wheel arrangement of the mobile robot is continuously adjusted so as to obtain the maximum energy efficiency of the motors during navigation. In addition, new omnidirectional wheels which can be transformed to the conventional wheels depending on the driving conditions are proposed to compensate for less efficient omnidirectional drive mode. Various tests show that motion control of the OMR-SOW works satisfactorily and the proposed steering algorithm for CVT can provide higher energy efficiency than the algorithm using a fixed steering angle. In addition, it is shown that the differential drive mode can give better energy efficiency than the omnidirectional drive mode.

• Journal of Gifted/Talented Education
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• v.11 no.1
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• pp.99-117
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• 2001

This study looked at the validity of assessments of academic giftedness in young children, details of assessment procedures and tasks related to them. It has shown that academic giftedness in young children can be reliably observed and reported by parents and teachers through similar characteristics to older gifted children. But for young preschool children since the potentiality rather than the current performance level is more important to detect and children's abilities are not fully differentiated, more systematic and comprehensive assessments are needed. Parents'and/or teachers' referrals, behavior checklists for the gifted, tests for creativity, short or group forms of standardized tests and finally individualized tests can be used as a comprehensive battery but these methods can be used stepwise for the sake of efficiency and economy. Especially the variability of performance in young children during the rapid developmental phase as well as their vulnerability by situational factors ask for the repeated assessments as regular bases. In this study different measures for gifted young children, specialists' qualification, and procedural guidance were reviewed and the necessity for various screening tools for different programs for the gifted was discussed. Finally it was emphasized that early assessment and following educational arrangement are needed for gifted young children for their optimal development.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.155-163
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• 2007

In this paper, Though sensors of Ubiquitous Middle-ware System based on RFID/USN can usually be reacted from six mouths to two years, they can be exhausted their power of storage battery only one day by communication rates and ranges. That is, the lifetime of sensor node is depended on how much spending power under wireless communication that can communicate its sensing data to its destination. Therefore, it is necessary that each sensor should be designed the Routing path to its destination, in order to remote collecting data. But, in order to improve lifetime of sensor node and modify inner setting, it is opposite to simple searching path method of sensor node by entering external commands. accordingly, 1:n sensor arrangement of n form command and data send-receive that is possible simulation do without interference other sensors and research to different sensor data analysis and conversion ways to convert Sensing data that accept from sensors to actuality information.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.43-48
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• 2009

We investigated the nutritional state of B vitamins and the neuropsychological functions in 25 subjects, aged $63.1{\pm}6.3$ years, residing in rural areas of Korea. Nutritional states of thiamin, riboflavin, and pyridoxine were assessed enzymatically in the erythrocytes, and folate concentrations were measured microbiologically in the plasma and erythrocytes. A battery of composite neuropsychological test was administered to the subjects. Plasma folate was correlated with the total intelligence score (p=0.049). Folate levels in the erythrocytes were correlated with the performance intelligence scores such as block design (p=0.017) and picture arrangement (p=0.016). The red cell folate was correlated with memory scores such as general memory (p=0.009) and delayed recall (p=0.000). Although it did not reach statistical significance, verbal memory (p=0.053) was highly correlated with the red cell folate. The red cell folate was also correlated positively with the percent of conceptual level response number score (p=0.029), and negatively with the grooved pegboard test score for the non-dominant hand (p=0.010). Fine motor coordination was also influenced by folate nutrition, as finger tapping scores in both hands were significantly correlated with red cell folate (dominant hand; p=0.026, non-dominant hand; p=0.004). Other B vitamins such as thiamin, riboflavin, and vitamin $B_6$ were not as strongly correlated with neuropsychological function test scores as folate was. These results suggest that folate nutrition influences neuropsychological function test scores significantly in humans. Further studies are needed to explore the relationship between folate or other vitamin B nutrition and neuropsychological functions and the implications thereof.