• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.45-52
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• 2023

The power generation method using expensive diesel has operation problems such as high cost diesel generator and a lack of reserved power due to increase of power demand in some islands, requiring expansion of power generation facilities. To solve this problems, it is necessary to improve the efficiency of power generation facilities through an ORC(Organic Rankin Cycle) system application that uses waste heat as a heat source. Therefore, localized application technology of price competitive and highly reliable ORC power generation system is needed, and optimization technology of generators is having great effect, so this study performed two generator designs to get a high-efficiency generator with an optimized 30kW output. The comparison of simulation data for two designed models showed that a generator with SPM factor of 46.2% had an efficiency of 92.1% and a power ouput of about 23.2kW based on 12,000rpm, a generator with SPM factor of 44.46%, had a power output of 27.9kW and efficiency of 93.6% based on above rpm. For the verification of improved design model with SPM factor of 44.46%, the prototype test system with 110kW motor dynamometer was installed and got to the efficiency of 92.08% with conditions of the rated capacity 25kW at 12,000rpm, the test results of prototype generator showed the validity of generator design.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.215-222
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• 2018

In this paper, the research on the energy storage system adapting super-capacitor has been performed. The most advanced features compared to the conventional lead-acid battery systems is that it can obtain high power capability due to the super capacitor power characteristics. The suggested system can attain high power in short times and achieve high power quality improvements. The application areas are power quality improvement system, motor start power which requires high power during transient times. The energy conversion system consists of bi-directional converter and inverter and advantages of high speed, high power charging and discharging performances. The design steps for the two loop controller of the bi-directional inverter are suggested and verified by the experiment and manufacturing. The two loop controller design starts from linearized transfer function which is calculated from the state averaging model including state decoupling method. The current controller requirements are 20% overshoot and settling time and voltage controller are no overshoot and settling time which is 10 times longer than current controller. The design is verified from the step input response. The designed controllers have unity power factor characteristics and thus can improve the power quality of the grid. It also has fast response time and zero steady state error.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.98-107
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• 2010

This paper introduces step by step procedures for the design, fabrication and operation of a solar tracking system. The system presented in this study consists of motion controllers, motor drives, step-motors, feedback devices and other accessories to support its functional stability. CdS sensors are used to constantly generate feedback signals to the controller, which assures a high-precision solar tracking even under adverse conditions. It enables instant correction if the system goes off track by strong winds causing gear backlash. A parabolic dish concentrator is mounted on the tracking system whose diameter was 30cm. The solar position data, in terms of azimuth and elevation, sunrise and sunset times were compared with those of the Astronomical Applications Department of the U.S. Naval Observatory. The results presented here clearly demonstrate the high-accuracy of the present system in solar tracking, which are applicable to many existing solar systems.

• The Journal of Korean society of community based occupational therapy
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• v.1 no.2
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• pp.71-79
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• 2011

Objective : This study aimed to systematically reviewed to identify, evaluate, synthesize the research literature and suggested to the research direction on the effectiveness of occupational therapy using a sensory integration approach. Methods : We analyzed 10 studies that identified the effectiveness of occupational therapy using a sensory integration approach for children and adolescents offering in MEDLINE/PubMed and http://ajot.aotapress.net between 1993 and 2011. Results : The subjects were the sensory modulation disorder and autism spectrum. The different intervention strategies were similar to a previous studies. Intervention dosage was over 20 sessions, 2~3days per week more than 10weeks. Occupational therapy using a sensory integration approach may result in positive outcome in motor performance, behavioral outcomes, academic and psychoeducational outcomes and tried to currently identify the effect of intervention outcomes in sensory processing and occupational performance using the GAS. Conclusion : Clinicians have a minimal idea planing a research design and a evidence running a study.

• Physical Therapy Rehabilitation Science
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• v.2 no.2
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• pp.87-91
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• 2013

Objective: The present study was aimed at determining the effect of physical training on glutamate transporter activity in a middle cerebral artery occlusion (MCAO)-induced ischemia injury rat model. Design: Randomized controlled trial. Methods: In this study, we randomly divided them into three groups. Group I included non-occlusion sham controls (n=10), Group II included non-physical training after MCAO (n=10), and Group III included rats that were subjected to physical training after MCAO (n=10). Rats in the physical training group underwent treadmill training, which began at 24 h after MCAO and continued for 14 consecutive days. The training intensity was gradually increased from 5 m/min on the first day to 12 m/min on day 3, and it was maintained until day 14. Focal cerebral ischemia was examined in adult male Sprague-Dawley rats by using the MCAO model. We determined the functional outcomes for each rat on days 1, 7, and 14. Glutamate transporter-1 (GLT-1) activity in the cortex of rats from all three groups was examined at the end of the experiment. Results: Out result show that MCAO rats exhibited severe neurological deficits on the 1 day, and there was no statistically significant in each groups. We observed that the functional outcomes were improved at days 7 and 14 after middle cerebral artery occlusion, and GLT-1 activity was increased in the physical training group (p<0.05). Conclusions: These results indicated that physical training after focal cerebral ischemia exerts neuroprotective effects against ischemic brain injury by improving motor performance and increasing the levels of GLT-1 activity.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.53-60
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• 2020

With the major advancement of vehicle-related technologies and services, the demands for the in/out-vehicle service expansion increase significantly. The key importance of the service expansion is to provide various vehicle-centric services in addition to improve the convenience and usability of users with connectivity. Recently, Internet of Things (IoT) gains major attention for small device connectivity and service, and it widens its area to other industries including automotive to advance and diversify its services. In this paper, we investigated the technical direction of the IoT service with the analysis of IoT technologies in the perspective of the vehicle. At first, we analyzed the vehicle and IoT services in each so that we are able to suggest the service design guideline and consideration to release integrated services between vehicle and IoT. Also, we reviewed the cases of few vehicle and home IoT integration services for the major insights and future direction of the integration services.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.56-63
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• 2016

This paper presents a novel method for detecting a ghost key at the membrane type keyboard, which has additional resistive coating to the membrane film. Also, the optimal ratio of resistances for detecting a ghost key was designed based on the characteristics of the membrane film. The optimal ratio of resistances was considered to be able to detect the worst case (i.e., difference voltage between normal key and ghost key is minimum). The ability of the proposed methods are evaluated by simulation studies in this paper. In order to verify the proposed method, the experiment was carried out with a designed circuit and A/D (analog to digital) in MCU (micro controller unit). The proposed method is implemented into the membrane type keyboard and is verified by experimental results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.3
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• pp.187-192
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• 2020

To reduce fuel consumption by reducing the weight of the deck of a dump truck and to design an eco-friendly deck, accurate structural analysis is required. To date, the load on the deck has been calculated based on the hydrostatic pressure or by applying the earth pressure theory. However, these methods cannot be used to determine the non-uniformity of the load on the deck. Load distribution varies depending on the size distribution and interaction of aggregate particles. Compared with the finite element method, the discrete element method can simulate the behavior of aggregate particles more effectively. In this study, major properties were obtained by measuring bulk density and repose. The deck of a 15 ton dump truck was simulated using the obtained properties and bumping, breaking, and turning load conditions were applied. EDEM, which is a discrete element analysis software, was employed. The stress and strain distribution of the deck were calculated by NASTRAN and compared with the measured values. The study revealed that the results derived from a DEM simulation were more accurate than those based on mathematical assumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1225-1230
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• 2017

3D printers have been growing mainly in industrial use, but the recent growth of the personal 3D printer market advanced through economic effects and cost reduction due to technological development. However, current 3D personal printers are very low in customer satisfaction on the limitations of molding speed, size, and precision. In this paper, we propose SLA 3D printer using LSU to overcome the technical limitation of personal 3D printer. In order to verify the operation of the scanning mechanism which is responsible for core functions, the movement of molding board using stepping motor and laser output test was conducted. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the traditional low-budget 3D printer.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.4
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• pp.334-341
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• 2015

This paper develops a new system for remotely monitoring and controlling the windows and doors in mobile environment. We design and implement the opening and shutting unit, the gateway, and the control server system, respectively. The opening and shutting unit consists of the driver using DC motor and the motion controller which monitors the state and transfers the control information. The gateway supports TCP/IP and CDMA protocol, which is the interface of wire and wireless communication for transferring the current state and control information. The control server consists of the program to store and process the control information, the middleware to support the processing of various state message, and DB for monitoring the state and remotely controlling the system. Especially, an application software and the Web-based user interface have also been developed to support the mobile environment. The operation performances, environment influences, driving persistences, and operation failure ratio, which are based on PC and smart-phone, have been tested in 2 authorized agencies. The test results show that the developed system has a superior performance.