• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.541-545
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• 2010

Because contemporary rolling stock system is complex and highly advanced, and it builds mutual interface, it is necessary to manage maintenance of rolling stock systematically. This study present a case, which shows how to adopt and apply RTD(Remote Transmission Device) integrated to train information collection device. After the train service is complete and the train enters the main subway station, various kinds of information collected from TCMS(Train Control Monitoring System) is transmitted to train depot information collection device through RTD. This study suggests that RTD integrated to train information collection device helps build an effective rolling stock maintenance system by improving reliability of data transmission and cutting maintenance costs.

• ETRI Journal
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• v.37 no.6
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• pp.1176-1187
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• 2015

This work proposes a highly efficient sensorless motor driver chip for various permanent-magnet synchronous motors (PMSMs) in a wide power range. The motor driver chip is composed of two important parts. The digital part is a sensorless controller consisting mainly of an angle estimation block and a speed control block. The analog part consists of a gate driver, which is able to sense the phase current of a motor. The sensorless algorithms adapted in this paper include a sliding mode observer (SMO) method that has high robust characteristics regarding parameter variations of PMSMs. Fabricated SMO chips detect back electromotive force signals. Furthermore, motor current-sensing blocks are included with a 10-bit successive approximation analog-to-digital converter and various gain current amplifiers for proper sensorless operations. Through a fabricated SMO chip, we were able to demonstrate rated powers of 32 W, 200 W, and 1,500 W.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.1
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• pp.14-19
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• 2008

Semiconductor testing area challenges many testing issues due to the minimization and ultra high performance of current semiconductors. Among these issues, signal integrity test on interconnections must be solved for highly integrated circuits like SoC. In this paper, we propose an effective pattern application method for signal integrity test on interconnects. Proposed method can be applied by using boundary scan architecture and very efficient test can be preceded with pretty short test time.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.2
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• pp.101-107
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• 2018

As indoor pollutants such as carbon dioxide and dust mainly affect the respiratory and circulatory systems, there is an increasing need for real-time indoor / outdoor environmental monitoring. In this paper, we have developed a real - time environmental monitoring system using the cloud-based 3G integrated environmental sensor module for environmental monitoring. A highly reliable environmental information monitoring system requires various IT technologies such as infrastructure (server, commercial software, etc.), service application software, security, and authentication. A real-time environment monitoring system based on cloud service that can provide reliable service satisfying these configuration requirements is proposed and implemented. It is expected that this system can be applied to various technologies such as indoor automatic window opening/closing system based on the Internet.

• Journal of Family Resource Management and Policy Review
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• v.20 no.2
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• pp.165-184
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• 2016

This study was conducted to identify factors which predict and discriminate women' reemployment. 288 married women whose careers had been interrupted for more than 1 year and 287 married women who re-entered into the labor market within 5 years were surveyed. Collected data were analyzed by logistic regression analysis. In the personal factor(reemployment need), proximal context factors(career barriers, family support and expectation for reemployment) and background context factors(SES, family life cycle), background context factors were revealed not to predict significantly women's reemployment. Secondly, in the case of proximal context factors, it was found that 'expectation of family members for reemployment' and 'sharing family care' had strong effects on reemployment. And compared with interrupted women, reemployed women were less likely to perceive career barriers. Specifically, they showed lower expectation to their job and status which they would achieve, less perceived gender/age discrimination in labor market, and had more confidence that they could find a job. Finally, with regard to the personal factor (reemployment need), the lower women had self-actualization need, the higher economic need, and the higher social need, it was highly likely to classify into reemployed women. We discussed the way to improve reemployment of career interrupted women based on above mentioned findings.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.414-424
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• 2017

This paper introduces an experimental device which can measure accurate aerodynamic forces without support interference in wide experimental region for wind tunnel test of micro aerial vehicles (MAVs). A stereo pattern recognition (SPR) method was introduced to a magnetic suspension and balance system (MSBS), which can eliminate support interference by levitating the experimental model, to establish wider experimental region; thereby MSBS-SPR integrated system was developed. The SPR method is non-contact, highly accurate three-dimensional position measurement method providing wide measurement range. To evaluate the system performance, a series of performance evaluations including SPR system measurement accuracy and 6 degrees of freedom (DOFs) position/attitude control of the MAV model were conducted. This newly developed system could control the MAV model rapidly and accurately within almost 60mm for translational DOFs and 40deg for rotational DOFs inside of $300{\times}300mm$ test section. In addition, a static wind tunnel test was conducted to verify the aerodynamic force measurement capability. It turned out that this system could accurately measure the aerodynamic forces in low Reynolds number, even for the weak forces which were hard to measure using typical balance system, without making any mechanical contact with the MAV model.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.349-362
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• 2018

A non-linear numerical simulation technique for predicting the unsteady performances of an airbreathing engine is developed. The study focuses on the simulation of integrated propulsion systems, where a closer coupling is needed between the airframe and the engine dynamics. In fact, the solution of the fully unsteady flow governing equations, rather than a lumped volume gas dynamics discretization, is essential for modeling the coupling between aero-servoelastic modes and engine dynamics in highly integrated propulsion systems. This consideration holds for any propulsion system when a full separation between the fluid dynamic time-scale and engine transient cannot be appreciated, as in the case of flow instabilities (e.g., rotating stall, surge, inlet unstart), or in case of sudden external perturbations (e.g., gas ingestion). Simulations of the coupling between external and internal flow are performed. The flow around the nacelle and inside the engine ducts (i.e., air intakes, nozzles) is solved by CFD computations, whereas the flow evolution through compressor and turbine bladings is simulated by actuator disks. Shaft work balance and rotor dynamics are deduced from the estimated torque on each turbine/compressor blade row.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.133-144
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• 2022

Fast-paced industrial and agricultural development generates large quantities of hazardous heavy metals (HMs), which are extremely damaging to individuals and the environment. Research in both academia and industry has been spurred by the need for HMs to be removed from water bodies. Advanced materials are being developed to replace existing water purification technologies or to introduce cutting-edge solutions that solve challenges such as cost efficacy, easy production, diverse metal removal, and regenerability. Water treatment industries are increasingly interested in activated carbon because of its high adsorption capacity for HMs adsorption. Furthermore, because of its huge surface area, abundant functional groups on surface, and optimal pore diameter, the modified activated carbon has the potential to be used as an efficient adsorbent. Metal-organic frameworks (MOFs), a novel organic-inorganic hybrid porous materials, sparked an interest in the elimination of HMs via adsorption. This is due to the their highly porous nature, large surface area, abundance of exposed adsorptive sites, and post-synthetic modification (PSM) ability. This review introduces PSM methods for MOFs, chemical modification of activated carbons (ACs), and current advancements in the elimination of Pb²⁺, Hg²⁺, and Cd²⁺ ions from water using modified MOFs and ACs via adsorption.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.162-169
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• 2022

In an attempt to disseminate modernized Korean traditional housing (Hanok), a ten-year research project was initiated in 2010 by the Korean Government to reduce the construction cost, improve the facility performance, and automate the Hanok construction industry. To meet these objectives, various research areas, including public policies, planning methods, design standards, new building materials, construction standards, maintenance procedures, advanced project management tools, and integrated IT applications have been developed. In addition, comprehensive technologies developed were applied to the ten pilot Hanok buildings to validate the real-world performance as part of the research project. To further facilitate the digital transformation of the Hanok industry by using the research results, it is required to disseminate the developed technologies in an automated and standardized manner. In particular, it is crucial to systematize and manage the interoperability of various technical data and accumulated historical data for different business functions, especially within the highly fragmented industry. In this context, this paper proposes an ontology-based Hanok information dissemination platform to enable industry-wide automated knowledge and information sharing. The system architecture, standardized historical database, and advanced analytics based on ontology web language (OWL) for the Hanok industrialization platform are introduced.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2047-2052
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• 2023

Risk-informed approach has been widely applied in the safety design, regulation, and operation of nuclear reactors. It has been commonly accepted that risk-informed design optimization should be used in the innovative reactor designs to make nuclear system highly safe and reliable. In spite of the risk-informed approach has been used in some advanced nuclear reactors designs, such as Westinghouse IRIS, Gen-IV sodium fast reactors and lead-based fast reactors, the process of risk-informed design of nuclear reactors is hardly to carry out when passive system reliability should be integrated in the framework. A practical method for new passive safety reactors based on probabilistic safety assessment (PSA) and passive system reliability analyze linking is proposed in this paper. New three-dimension frequency-consequence curve based on risk concept with three variables is used in this method. The proposed method has been applied to the determination optimization of design options selection in a 10 MWth lead-based research reactor(LR) to obtain one optimized system design in conceptual design stage, using the integrated reliability and probabilistic safety assessment program RiskA, and the computation resources and time consumption in this process was demonstrated reasonable and acceptable.