• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.129-135
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• 2015

This paper shows significant methods that improve the lifespan of LED modules as well as efficiently using an aluminum heat-sink for LED module in high power. It proposes a method that raises stability and lifespan to protect LED modules and the power unit when the LED module has been used for a long hours at high temperatures. During the research, we applied a method of pulse-width modulation (PWM) in order to prevent the phenomenon that the entire power of a system is turned off and the lifespan is reduced when the LED nodule reacts to the high temperatures. To protect the LED module and SMPS based on high efficiency, a temperature sensor is attached underneath the circuit board and the sensor measures the temperature of circuit board when the LED module is powered on. The electrical power connected to SMPS is controlled by PWM when the temperature of the LED module reaches a particular temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.1021-1027
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• 2012

In this paper, multi-string power balancing system for streetlight was developed. Accordingly, the components of the system was developed, unit converters, MPPT control unit, a bank of Li-ion battery and controls the charging and discharging. Loss by improving the efficiency of the system through the parallel operation of the unit converter output will be reduced. And by improving the efficiency of the system through the unit converter parallel operation, output losses will be reduced. Charging and discharging efficiency of the device used in a typical solar streetlight is calculated based on the maximum power input. Because of the variation of the input power has a weakness. In this paper, flexible to changes in the input, and a system was developed to minimize the cost per watt. Measure the performance of the unit module from the system, the result was more than 91%. And the charging capacity 12 V/105 Ah, module power 180 W, respectively. Should expect to be able to improve performance through continuous monitoring in the future.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2828-2839
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• 2022

This study developed a safety assessment tool for geological disposal systems called APro, a systemically integrated modeling system based on modularizing and coupling the processes which need to be considered in a geological disposal system. Thermal, hydraulic, chemical, canister failure, radionuclide release and transport processes were considered in the current version of APro. Each of the unit processes in APro consists of a single Default Module, and several Alternative Modules which can increase the flexibility of the model. As an initial stage of developing the modularization concept and modeling interface, the Default Modules of each unit process were described, with one Alternative Module of chemical process. The computation part of APro is mainly a MATLAB workspace controlling COMSOL and PHREEQC, which are coupled by an operator splitting scheme. The APro model domain is a stylized geological disposal system employing the Swedish disposal concept (KBS-3 type), but the repository layout can be freely adjusted. In order to show the applicability of APro to the total system performance assessment of geological disposal system, some sample simulations were conducted. From the results, it was confirmed that coupling of the thermal and hydraulic processes and coupling of the canister failure and the radionuclide release processes were well reflected in APro. In addition, the technical connectivity between COMSOL and PHREEQC was also confirmed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.515-520
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• 1998

In this paper, we propose a new fault tolerant architecture for high availability systems, where for module internal operations both processor modules perform the same tasks at the same time independently of each other while for module external operations both processor modules act actively. That is, operations of synchronization between dual processor modules except clock synchronization are requested only when module external operations are executed. The architecture can not only improve system availability by reducing system reintegration time but also reduce performance degradation problem due to frequent synchronization between dual processor modules. The clock unit consists of a clock generator and a clock synchronization circuit. This supplies a stable clock signal under clock unit disorder of any processor module or rapid clock signal variation. And this architecture achieves system availability and data credibility by designing as symmetrical form.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.646-656
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• 2008

In this paper, we design and verify the MAC chip of the two-stage AWG-based WDM-PON which considers 128 ONUs and 32 wavelengths. Each wavelength with the capacity of 1Gbps is allocated to ONU for downstream transmission but each wavelength for upstream transmission can be shared by four ONUs. Therefore, MAC protocol is required to avoid the collision and use the network resource efficiently among ONUs which are sharing the same wavelength. To design a request/permit-based MAC protocol, we define a unit-chip module called sub-MAC. The WDM-PON with 128 ONUs can be implemented by using 32 sub-MAC modules. The sub-MAC consists of one control unit, one receipt unit and four transmission units. The state transition diagram of the module is described by the internal/external control signals among the functional units. The function of the sub-MAC module is verified through logic simulation using ModelSIM.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1428-1431
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• 1997

This paper presents an efficient fault diagnosis methodology for lare chemical processes. The methodology is based on a two-tier strategy, When a falt occurs in a process, a top tier identifies the sector (process part or unit) that may contain the fault(s). Afterwards, a bottom tier or lower level evaluates the suspicious sector. The process modeling methodology based on functionality-behavior relations of process units, is proposed and utilized in the top-tier. This methodology models a target process as sequences of functions and variables and their relations. In the bottom tier, each sector has a dedicated diagostic module, which is tailored to the available information or models of the sector. For the sectors selected in the top-tier diagnosis, each diagnostic module is executed to identify the actual faults within the sector. Teh utility of the methodology is illustrated in the diagnosis of the CSTR with heat exchanger.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.2
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• pp.62-67
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• 2011

In this paper, Multi Mode Receiver Module is designed in one H/W module for Multi-mode Digital Broadcasting. Multi mode means Digital TV, Mobile TV and Digital Radio on the Broadcasting. and T-DMB, DAB(+), ISDB-T and DVB-T standard. Our Module can receive various broadcasting signal such as ISDB-T, DVB-T and DAB. The Multi mode Receiver Module & demuxer was implemented using the one SoC Chip has good performances to receive the multi mode signals as well as standard interface such as SPI, to connect the main CPU Unit.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.304-314
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• 2005

The present study aims to develop animation module-based teaching-learning materials for a unit of middle school 3rd grade science, which contains the movement of the solar system, through the utilization of various forms of multimedia elements. The developed materials consist of 12 in total flash animation modules covering ‘movement of the Earth,’ ‘movement of the Moon,’ movement of the Planets,‘ etc. To analyze the student responses to the science classes to which the developed animation modules were to be applied, the researcher selected for subjects two third-grade classes that were made up of 60 students and later divided for an experimental group and a control group in a middle school located in Jeonju. The experimental group was treated with the animation module-based lessons developed in the present study while the control group was taught in the traditional teacher-centered ways. Tests for the science-related attitudes of the two groups were administered and the results showed that the mean score of the experimental group was significantly higher than the mean score of the control group (p<0.05) in the categories of ‘interest’ and ‘scientific attitude’. It was thus believed that the animation module-based teaching has a positive effect on the categories of ‘interest’ and ‘scientific attitude’. To assess the qualitative dimension of the developed materials, the researcher subjected them to the utilization of the 30 local science teachers and afterwards a survey was done with the 8 crucial items taken from the WBI evaluation test developed by Multimedia Education Support Center in 1998. The result was broadly positive in terms of lesson design and from a technological point of view.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.294-301
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• 2010

In order to produce a convenient robot for the aged and the lower limb disabled, it is needed for the research detecting implicit walking intention and controlling robot by a user's intention. In this study, we developed sensor module system to control the walking- assist robot using FSR sensor and tilt sensor, and analyzed the signals being acquired from two sensors. The sensor module system consisted of the assist device control unit, communication unit by wire/wireless, information collection unit, information operation unit, and information processing PC which handles integrated processing of assist device control. The FSR sensors attached user's the palm and the soles of foot are sensing force/pressure signals from these areas and are used for detecting the walking intention and states. The tilt sensor acquires roll and pitch signal from area of vertebrae lumbales and reflects the pose of the upper limb. We could recognize the more detailed user's walking intention such as 'start walking', 'start of right or left foot forward', and 'stop walking' by the combination of FSR and tilt signals can recognize.

• 대한공업교육학회지
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• v.30 no.2
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• pp.33-44
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• 2005

The purpose of this study is to suggest plans to improve the industrial high school through the inquiry of Competency-Based Education(CBE). The suggestions are as followings: (1) Selection and organization of the educational contents of industrial high school must be based on job analysis. (2) Instructional objectives must be defined as a performance objective and enabling objectives. (3) Instruction must be individualized in method, the instructional contents must be organized in the unit of module. (4) Evaluation system must be not knowledge based but performance-based. (5) Physical Environment of work shop must be organized based on facilities, equipments and machines abstracted by job analysis. (6) Competency-Based Teacher Education(CBTE) program is required to train competent teachers in practice.