• Journal of information and communication convergence engineering
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• v.3 no.3
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• pp.137-141
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• 2005

The paper presents some methods to improve characteristics of film bulk acoustic resonator (FBAR) devices. The FBAR devices were fabricated on Bragg reflectors. Thermal treatments were done by sintering and/or annealing processes. The measurement showed a considerable improvement of return loss $(S_{11})$ and quality factor $(Q_{s/p}).$ These thermal treatment techniques seem very promising for enhancing FBAR resonance performance.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1494-1496
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• 2007

This paper deals with image quality analysis considering the impact of psychological factors involved in assessment. The attributes of image quality requirement were partitioned according to the visual perception characteristics and the preference of image quality were obtained by the factor analysis method. The features of image quality which support the subjective preference were identified, The adequacy of image is evidenced to be the top requirement issues to the display image quality improvement.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.252-253
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• 2005

This paper describes a improvement of power control characteristics of ship's emergency lighting power supply(SELPS), that power factor(PF) is improved and electric power is controlled extensively, and power ON-OFF is controlled and system parameter monitored in remote distance by PC serial communication.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.308-313
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• 2005

An urban railway vehicle has a characteristics such as that a lot of passenger use it and the major of passenger is standee. The ride comfort of standee is greatly influenced by the lateral dynamic characteristics of vehicle. So the lateral vibration is important factor for the improvement of ride comfort. In this study, vibration test of railway vehicle is carried out under the same condition of field driving to find out the major factor of vibration. By considering the test results under the various driving condition, the vibrational characteristics of vehicle is verified.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.311-314
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• 2002

In recent years, various power factor correction(PFC) circuits for the electronic ballasts have been proposed. In this paper, we have studied several passive PFC and compared with their characteristics, used in the electronic ballast for fluorescent. Especially, Improved Valley Fill Circuit (IVF) and the circuit IVF PFC combined with Charge Pumping Capacitors(CPCs) have been reaserched for High Power Factor. In conclusion, we have researched characteristics of Passive PFC and proposed the most effective PFC method.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.547-548
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• 2006

In this paper, cost effective parallel-branch inductor has been proposed and developed in order to increase the quality factor of the conventional spiral inductor. This parallel-branch inductor is composed of only two metals. The presented parallel-branch inductor shows 12% improvement in the quality factor with the same area as the conventional inductor. Also, we improve the parallel-branch inductor for high frequency applications.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.169-178
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• 2000

The 4-point bending tests have been performed In order to estimate the effect of TIG-dressing on fatigue strength and fatigue characteristics quantitatively for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue tests, fatigue strengths of as-welded specimens have satisfied the grade of fatigue strength prescribed in specifications of korea, AASHTO and JSSC. Fatigue strength at 2 million cycles of TIG-dressing specimens have increased compared with as-welded specimens. As the result of beachmark tests, fatigue cracks occurred at several points, where the radius of curvature and flank angle in the weld bead toes were low, and grew as semi-elliptical cracks, then approached to fracture. As a result of finite element analysis, stress concentration factor in weld bead toes has closely related to the flank angle and radius of curvature, and between these, the radius of curvature has more largely affected in stress concentration factor than flank angle. As a result of fracture mechanics approaches, the crack correction factor of test specimens has largely affected on stress gradient correction factor in case a/t is below 0.4. From the relations between stress intensity factor range estimated from FEM analysis and fatigue crack growth rate, fatigue life has been correctly calculated.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.6
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• pp.105-114
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• 2007

This study is to predict the spatial expansion of urban areas by applying CA(Cellular Automata)-Markov technique considering MCE(multi-criteria evaluation) and MOLA(multi-objective land allocation) of factor analysis. For the 10 administration districts$(3677.3km^2)$ including the whole Anseong-cheon watershed, the past six temporal land use data(1973, 1981, 1985, 1990, 1994, 2000) from Landsat satellite images were prepared. During this period, the urban area increased $233.71km^2$. Using the 36 indices composed of topological characteristics, population and land use change, the final factor map of MOLA was produced through 5 maps of MCE. Using 1990 and 1994 land use data, the 2000 predicted urban area of CA-Markov with factor map showed 0.06% improvement of absolute error comparing with that of CA-Markov without factor map. By the CA-Markov technique considering factor map, the 2030 and 2060 urban area increased $58.94km^2(0.78%)\;and\;60.14km^2(0.81%)$ respectively comparing with 2000 urban area$(313.19km^2)$. The 2030 and 2060 paddy area decreased $93.28km^2(2.54%)\;and\;93.65km^2(2.55%)$ respectively comparing with 2000 paddy area$(1383.23km^2)$.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.27-33
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• 2009

New optical transmission link techniques improving performance of WDM channels, each channel have bit rate of 40 Gbps, are proposed. The proposed optical link configuration consist of optical phase conjugator (OPC) placed at middle of total transmission length, and dispersion management (DM) as a role of compensating dispersion cumulated in transmission line. It is confirmed that Q-factor of total channels are improved by combining OPC and DM in optical transmission link as a result of following fact; DM not only mitigate the cumulated dispersion in total transmission line but also help OPC to compensate optical nonlinearities. And, it is confirmed that the improvement of Q-factor of overall WDM channels depends on net residual dispersion (NRD) of optical link.

• The Korean Journal of Emergency Medical Services
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• v.22 no.2
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• pp.35-49
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• 2018

Purpose: This study aimed to develop a resilience measurement scale and verify its validity and reliability. Methods: This was a methodological study. The preliminary items of the scale were derived from literature reviews and in-depth interviews. The data were collected from October 30, 2017 to January 20, 2018, and paramedics working in hospitals or fire departments were selected using convenience sampling. A self-reported questionnaire was completed by 213 paramedics in Korea. Results: Through content validity, item analysis and exploratory factor analysis, a total of 6 factors and 26 items were extracted, and the total variance was 67.12%. Factor 1 was "self-efficacy" (11 items), factor 2 was "internal control" (5 items), factor 3 was "empowerment" (2 items), factor 4 was "interpersonal capability", (3 items), factor 5 was "social support" (2 items), and factor 6 was "adaptation and coping" (3 items). Conclusion: This is the first scale developed in Korea to measure the resilience of paramedics. In future, this scale of this study will contribute to developing a resilience improvement program based on understanding the resilience level of paramedics.