• Transactions of the Korean hydrogen and new energy society
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• v.24 no.6
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• pp.480-486
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• 2013

In this study, tubular SOFC unit cell with advanced anode current collector was fabricated to improve the cell performance. First, we prepared two types of single cells having the same manufacture processes such as the same electrolyte, electrode coating condition and sintering processes. And then to compare the developed single cell performance with conventional cells, we changed the anode current collecting methods. From the impedance analysis and I-V curve analysis, the cell performance of advanced cell is much higher than that of conventional cell.

• Journal of Engineering Education Research
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• v.14 no.3
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• pp.45-54
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• 2011

The purpose of this study is to analyze performance problems in establishing and improving program educational objectives (PEO) and to set up action strategies for the civil engineering program at the A university. To fulfill the purpose, according to the typical needs analysis model, research problems were defined, current conditions and desired conditions were identified, discrepancies and their reasons were examined, and action strategies were derived. Current conditions and desired conditions were identified by analyzing the A civil engineering program's self study report, conducting surveys and interviews with constituents. After the discrepancies and the reasons were examined, performance problems and field force analysis were conducted to draw short term and long term action strategies to improve PEO. Short term action strategies were to announce PEO to current students, to hold faculty seminars to establish and to improve PEO, to renew the list of constituents regularly, to composite an annual milestone, to define roles of the committees, and to enforce educational opportunity toward industrial advisory board members. For the long term strategies, improvement and documentation of PEO assessment system, collection and analysis of constituents' suggestions, establishment of effective accreditation support system, and arrangement of compensation system for the faculties who are in charge of engineering education accreditation responsibility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.502-502
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• 2007

A catenary system should be designed to have an uniform elasticity over a span in order to maintain the lowest possible loss of contact between a pantograph and a contact wire. A elasticity uniformity of a catenary can be regarded as a important design factor used for predicting the current collection performance for a catenary. There are a couple of formulas to calculate the degree of elasticity uniformity of a catenary according to the literature survey. The effectiveness of these formulas is reviewed by performing catenary elasticity and loss of contact analysis for various different configurations of catenary systems using a beam element based FEM program. The results reveals that these formulas are not suitable to predict the current collection performance for a catenary. Therefore, a new formula based on the standard deviation of the elasticity over a span is proposed in this study. The analysis results show that the new formula for an elasticity uniformity of a catenary is very effective in predicting the current collection performance for a catenary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.268-275
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• 2020

In domestic mountain resort areas, a catenary system cannot be installed for the protection of the natural environment and view. Therefore, mountain trams must be operated wireless. In this study, a local ground pantograph, which supplies electricity to the battery on board, was developed for this purpose, and its performance was verified by tests. The system is installed on ground at stops or repair shops. While a bogie goes to the pantograph, the arms and collection shoes are raised by a spring force to make contact with the collection bar under the bogie so electric power can be supplied to the battery. Because it is a local ground type, it does not require a roof pantograph and catenary system. The system enables the mountain tram to run wireless. In addition, there is no separation and arc because it collects current while standing at stops or shops. The system has a long life because moving contact, which generates wear and damage to shoes, is avoided. The insulation resistance was above the criteria of 10 ㏁, and there was no abnormal temperature increase when a current of 335A was supplied for one hour.

• Korean Journal of Artificial Intelligence
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• v.11 no.4
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• pp.21-27
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• 2023

This paper discusses a deep learning-based road surface analysis system that collects data by installing vibration sensors on the 4-axis wheel bearings of a vehicle, analyzes the data, and appropriately classifies the characteristics of the current driving road surface for use in the vehicle's control system. The data used for road surface analysis is real-time large-capacity data, with 48K samples per second, and the A2B protocol, which is used for large-capacity real-time data communication in modern vehicles, was used to collect the data. CAN and CAN-FD commonly used in vehicle communication, are unable to perform real-time road surface analysis due to bandwidth limitations. By using A2B communication, data was collected at a maximum bandwidth for real-time analysis, requiring a minimum of 24K samples/sec for evaluation. Based on the data collected for real-time analysis, performance was assessed using deep learning models such as LSTM, GRU, and RNN. The results showed similar road surface classification performance across all models. It was also observed that the quality of data used during the training process had an impact on the performance of each model.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.356-360
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• 2015

The specific role of current collectors was investigated at the electrolyte/electrode interface of solid oxide fuel cells (SOFCs). Ag grids were fabricated as current collectors using electrohydrodynamic (EHD) jet printing for precise control of the grid geometry. The Ag grids reduced both the ohmic and polarization resistances as the pitch of the Ag grids decreased from $400{\mu}m$ to $100{\mu}m$. The effective electron distribution along the Ag grids improved the charge transport and transfer at the interface, extending the active reaction sites. Our results demonstrate the applicability of EHD jet printing to the fabrication of efficient current collectors for performance enhancement of SOFCs.

• Quality Improvement in Health Care
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• v.5 no.2
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• pp.224-237
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• 1998

Background : This is an investigative study to analyse the importance of works perceived by Quality Improvement(QI) Coordinators and to evaluate their current work performances using the questionnaires developed by the investigator. Methods : The data were collected from 37 subjects over two weeks period from Oct. 1 to Oct. 17, 1998 and analysed by the descriptive statistics of SPSS program. The items of questionnaire are consisted of 13 work domains including 73 activities based on Quality Management(QM) Coordinator's job description of National Association for Healthcare Quality:data collection & analysis, communication, monitoring, evaluation, accreditation, tool development, policy development, program development, self development, education & trainning, system design, planning, and consultation & support. Results : 1) Of the performances in 13 work domains, the frequencies of the work performed were accreditation(89%), planning(88%), communication(83%), data collection & analysis(82%), monitoring(76%), policy development(72%), consultation & support (71%), education & trainning(70%), self development(68%), evaluation(63%), tool development(61%), program development(44%) and system design(43%) in order. 2) For the importances (1=not important, 5=very important), the policy development(4.46) scored highest then monitoring(4.42), planning(4.41), education & trainning(4.38), communication(4.35), evaluation(4.34) tool development (4.30), data collection & analysis(4.29), program development(4.22), consultation & support(4.22), accreditation(4.15), self development(4.05) and system design(3.98) in order. 3) There was a difference between the work performance and the perceived importance. The results showed the low performances in policy development, monitoring, education & trainning and evaluation which ranked high by the perceived importance and the high performances in accreditation, data collection & analysis, self development, communication and consultation & support which ranked middle to low by the perceived importance. 4) The reasons for low performances of QI Coordinators were the lack of clear assignment for the responsibility and allowed authority for work to QI Coordinators(30.8%), insufficient member of QI Coordinators(13.9%), lack of hospital director's interest(11.5%), low motivation of QI Coordinators (10.6%) and insufficient knowledge & experience of QI Coordinators (8.8%). Conclusion : Most works were perceived important by QI Coordinators, but there was a difference in the work performance. The works performed over 70% were related with accreditation, data collection & analysis, communication, planning and monitoring, on the other hand under 50% in performances were related with system design, program development, tool development and evaluation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.850-854
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• 2014

Analyzing dynamic performance between pantograph and contact wire depends on mechanical and electrical conditions such as contact force, currents, aerodynamics of pantograph and tension of overhead contact wire. For the characteristic of dynamic performance between pantograph and overhead contact wire, various evaluation systems are used to measuring of the interaction of the contact line and the pantograph. Among the various methods, the contact force and percentage of arcing are intended to prove the safety and the quality of the current collection system on the train. However, these methods are only capable of measuring on the train which are installed measurement systems. Therefore in this paper, a track-side monitoring system was implemented to measure electrical characteristics from active overhead contact wire systems in order to constantly estimate current collection performance of railway operation. In addition, a method to analyze loss of contact phenomena was proposed. According to simulation results, the proposed system was capable of measuring abnormal electrical behavior of pantograph and contact wires on the track-side. The advantage of the proposed system is possible to detect loss of contact or any other electrical abnormalities of all types of trains within sections from sub to sub without the need to install any on-board equipment on trains.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2171-2175
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• 2011

The objective of this paper is to discuss technologies on assessing reliability of arc detectors by composing a system that generates and simulates occurrence of arc caused by loss of contact between pantographs and contact wires in a laboratory condition. In order to establish the arc simulator, a device that generates light having the bandwidth of arcs that occur between carbon-metal. The simulator was designed under conditions of EN 50317 and simulations were conducted using the developed device. According to the results, it was possible to conduct certification tests following regulations of international standards and the precision of the simulator was satisfactory. The proposed arc detector assessment system is expected to enhance precision of current collection quality performance assessment methods at high-speed lines and conventional lines while being referred as fundamental technologies for development of detectors suiting international conditions.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.251-260
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• 2000

Seismic performance evaluation systems require rational classification of structure systems, proper evaluation criteria, and their scoring index for synthesis. Current seismic performance systems need expert judgments based on collection of available data, approximate analysis of important items, and various scoring system. This study presents a three-step seismic performance evaluation system for building structures in Korea. Each evaluation step determines the seismic performance and the method depends on the degree of refinement of analysis. The preliminary step evaluation involves the global attributes of structures such as vertical irregularity, asymmetric plan, redundancy, and age of structures. The second step requires an elastic analysis for estimation of forces acting on critical sections and checks the strength and ductility. The final step requires inelastic capacity of structures. Each stephas own evaluation scheme with proper weighing factor dependent on the importance and consequence. This study applies the fuzzy theory to a scoring method that synthesizes the individual quantity to a representative value.