• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.23-30
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• 2016

We report a STT-MRAM write-scheme, in which the length of the write-pulse is determined dynamically by sensing the status of MTJ cells. The proposed scheme can reduce the power consumption by eliminating unnecessary writing current after the switching has occurred. We also propose a reference cell design, which is optimized for the use in write-circuits. The performance of the proposed circuit was verified by SPICE level simulations of the circuit implemented in a $0.13{\mu}m$ CMOS process.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.64-73
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• 2016

In this research work, an algorithm development on tracking end-point of aerial work platform with jib profile and bend-linked boom was carried out to find the X, Y and Z direction value using coordinate transformation matrix. This matrix consists of device status value(length and angle) based on camera position axis, which are sent from device controller PLUS+1 by CAN protocol. These values are used to measure the distance and angle from the camera to the end-point. Using these distance and angle value, monitoring system controls FAN/TILT/ZOOM status of camera to get an adequate scene of workplace. This program was written in Java, C# and C for mobile device. These results provide the information to the aerial work device for secure operation.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1473-1478
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• 2007

In the respect of energy saving and reusing, it is necessary to reduce greenhouse gases emission and to enhance the operation efficiency in electric railway system. Recently, as the power electronics technologies are advanced, some countries have focused on the regenerative inverter to use regeneration energy on each line. When the electric tractions are stopped or slowed down, it is useful to supply the surplus energy to the power source by regenerative system, which increases its energy efficiency. Also, the generated energy can be supply to other tractions or equipments inside traction. Thus, it may help reduce construction cost of additional power plants. The purpose of this study is to describe the development status of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister.

• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.511-524
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• 1997

The curriculum of science should be made of the education based on the acquirement instead of the knowledge. However, the present educational environment has many problems such as lack of laboratory and experimental facilities, and time limitations. One of the suggested methods to overcome the barriers in regular curriculum is the efficient operation of science club activities. Since the club activities are not restricted on time and space, teachers can apply various methods and programs. In this paper, we investigate the present operational status of science club activities in secondary school and some suggested improvement schemes of them It is shown that teacher training, reference development, time allocation, educational environment, facility completion and various program developments should be preceded, in order to activate science club activities.

• Journal of Computational Design and Engineering
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• v.2 no.2
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• pp.119-127
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• 2015

In the case of a high-valuable asset, the Operation and Maintenance (O&M) phase requires heavy charges and more efforts than the installation (construction) phase, because it has long usage life and any accident of an asset during this period causes catastrophic damage to an industry. Recently, with the advent of emerging Information Communication Technologies (ICTs), we can get the visibility of asset status information during its usage period. It gives us new challenging issues for improving the efficiency of asset operations. One issue is to implement the Condition-Based Maintenance (CBM) approach that makes a diagnosis of the asset status based on wire or wireless monitored data, predicts the assets abnormality, and executes suitable maintenance actions such as repair and replacement before serious problems happen. In this study, we have addressed several aspects of CBM approach: definition, related international standards, procedure, and techniques with the introduction of some relevant case studies that we have carried out.

• Journal of The Korean Association For Science Education
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• v.10 no.1
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• pp.33-45
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• 1990

To achieve the aim of science education, it is known that warious teaching, and learning materials should have to be used. As a sub-textbook for primary science education, 'Sil Hum-Kwan Chal (Experiment and Observation), teaching and learing material are developed and using now in science. This material have following characteristics; (a) Soruce-book contains reading materials for additional information, various pictures to enririch the science concepts, and supplementary and enrichment activities. (b) Work-book consists of the detailed procedures of activities of experiments presented in the textbook, student can record the experimental procedures and results. (c) Operational manuals provide operation techniques for experimental equipments which are used in science class. In this study the using status are surveyed for the 3rd grade of primary school, and based on this survey the improvement plan are discussed in view of design, quantity and utility, of sub-textbook.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2402-2414
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• 1996

Registration is the process by which a base station gets the information of location and status about mobile stations. Registration will become an increasingly important issue in mobile cellular communications, especially in microcellular system with the increase of location updating traffic. Four typesof registration schemes, which are specified in US standard IS-95 and Korean standard TTA-KO-0062, power up registration scheme, power down registration scheme, distance based registration scheme and zone based registration scheme, will be mainly used in the future. In this paper, we derive the combined cost of signaling traffic of paging and registration for various parameters of mobile stations behavior(unencumbered call duration, power up and down rate, velocity, etc.) then we present numerical results for the perfroamnce of four registration schemes. The size of location area is provided for optimal operation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.3
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• pp.143-150
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• 2003

In this paper, we developed the window based monitoring system. This system offers the analysis of accidents in the power plants, the operating status of relays and the historical data with which the experts can offer the idea about the operation of the power system. And we can also monitor the status of the ACB and relay at a long distance by means of the function of communication in the digital protective relay itself. By means of the above functions, we developed the system, which is run after the diagnosis and maintenance of the electrical machines and an amount of data are realized by graphical method fitting the operating convenience of the users.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.287-291
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• 2006

The IEA Wind agreement for co-operation in the R&D of wind energy system was founded in 1974. The Korea has been a contracting party to the IEA wind energy program since 2003. The contracting parties are designated by the 20 member countries and the EC. IEA Wind agreement is for member countries to exchange information, knowledge and to organize international collaboration on R&D projects called Taskes and Annexes. The Executive Committee approves and controls the R&D Tasks, and its meetings are held twice a year. This paper describes the status of current 7 implementing Tasks that were reported to the recent 57th Executive Committee meeting this year in Brussels, Belgium.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.1
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• pp.99-104
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• 2022

In this paper, to increase the maintenance efficiency of the urban railway train control system and to build a standard data system, we collect as much as possible structured, unstructured, and semi-structured data, and collect data by sensing and monitoring the system status and system status and monitoring. pre-process function data(Identification, purification, integration, transformation) through effective data classification and maintenance activities business classification system was studied. The purpose of this is to define the data matrix model by considering the relationship with the data generated and managed in the O&M stage of the train control system operated by the urban railway together with the WBS model, and to reflect and utilize it in practice.