• Journal of the Society of Disaster Information
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• v.13 no.2
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• pp.233-248
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• 2017

Uniform laws and regulations and reasonable design is necessary for the prevention of possible fire in super high-rise building. To this end, this study focused on super high-rise and massive building-related architectural review performance-based design (PBD) evaluation disaster impact assessment (DIA), and provided fire engineering measures for improving fire prevention on the basis of performance-based design by analyzing the buildings subject to these systems and problems in terms of contents. Above all, in the aspect of law and standard improvement, first, with regard to dual parts of two statutes though significant portion of them has the same contents in performance-based design (PBD) evaluation and disaster impact assessment (DIA), it is necessary to operate the systems after making them conform with each other and consolidating or abolishing them. Second, if it is impossible to consolidate or abolish performance-based design (PBD) evaluation and disaster impact assessment (DIA), the areas of contents of performance-based design (PBD) evaluation and disaster impact assessment (DIA) should be precisely classified and established. Next, engineering improvement measures against fire hazard in super high-rise building are as follows. First, it is necessary to revise the provisions of straight-run stairs in special escape stairs. And in case of installing a mechanical smoke exhaust system instead of smoke vent, sandwich pressurization used in the United Stated should be permitted. Second, with regard to smoke control system for special escape stairs, it was shown that there was necessity for revising the standards in order to enable air to be supplied according to section in case of fire, carrying out performance-based design, and the like from the early design stages to the completion stages. In the future, it is expected that an epoch-making contribution will be made to a decrease in casualties and property damage due to fire in case of super high-rise building where the results can be reflected after carrying out a study on maintenance and carrying out an additional study on other considerations of super high-rise building together with reflecting the improvement measures provided in the above-mentioned study.

• The KIPS Transactions:PartD
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• v.14D no.1 s.111
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• pp.121-130
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• 2007

in a software development, the design or architecture prior to implementing the software is essential for the success. This paper presents a case that we successfully designed a software architecture of radiation monitoring system (RMS) for HANARO research reactor currently operating in KAERI by applying the quality attribute-driven design method which is modified from the attribute-driven design (ADD) introduced by Bass[1]. The quality attribute-driven design method consists of following procedures: eliciting functionality and quality requirements of system as architecture drivers, selecting tactics to satisfy the drivers, determining architectures based on the tactics, and implementing and validating the architectures. The availability, maintainability, and interchangeability were elicited as duality requirements, hot-standby dual servers and weak-coupled modulization were selected as tactics, and client-server structure and object-oriented data processing structure were determined at architectures for the RMS. The architecture was implemented using Adroit which is a commercial off-the-shelf software tool and was validated based on performing the function-oriented testing. We found that the design method in this paper is an efficient method for a project which has constraints such as low budget and short period of development time. The architecture will be reused for the development of other RMS in KAERI. Further works are necessary to quantitatively evaluate the architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.388-396
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• 2002

In this paper, An aperture-coupled microstrip patch antenna operating at WLL frequency range(Rx : 2.3∼2.33Ghz, Tx : 2.37 ∼2.4Ghz) for WLL repeater is designed and fabricated. FR-4 epoxy substrate with 4.7 relative permittivity is inserted between feed-line and patch plane. Aperture-coupled structure is employed for consideration of bandwidth improvement and gain\`s characteristics. Air gap is arranged at each layer for bandwidth extension and radome is used as a protector in the upper patch. In this paper, both 1 port and 2 port are designed as 1$\times$2 array antenna which uses T-junction and λ$\_$g//4 transformer. Here, 1 port is used as transmitting/receiving antenna and 2 port is used as receiving antenna. Functionally independent two antennas using space diversity arrange slots between two antennas in order to be placed at the same place. As a result, we obtained a excellent isolation below -40dB and return loss is reduced by means of slots arrangement between patch and antenna.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.421-426
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• 2009

This paper presents vibration analysis of maskless exposure module in Printed Circuit Board (PCB) manufacturing system. In order to complete exposure process in PCB, masking type module has been widely used in electronics industries. However, masking process confronts some limitations of application due to higher production cost for masking as well as lower printing resolution. Therefore, maskless exposure module is started to be in the spotlight for flexible production system to meet the needs of fabrication in variable patterns at low cost. Since maskless exposure process adopts direct patterning to PCB, vibration problems become more critical compared to conventional masking type process. Moreover, movements of exposure engine as well as stage generate vibration sources in the system. Thus, it is imperative to analyze the vibration characteristics for the maskless exposure module to improve the quality and accuracy of PCB. In this study, vibration analysis using the Finite Element Analysis is conducted to identify the critical structural parts deteriorating vibration performance. Also, Experimental investigations are conducted by single/dual encoder measurement process under the operating module speed. Measurement points of vibration are selected by three places, which are base of stage, exposure engine and top of stage, to check the effect of vibration from the exposure engine. Comparisons between analysis results and experimental measurement are conducted to confirm the accuracy of analysis results including the developed FE model. Finally, this studies show feasibility of optimal design using the developed FE analysis model.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.35-40
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• 2012

In DC-DC converters, a PWM/PFM dual mode control method is commonly used to maintain a high efficiency over a wide range of load variation. Since the control mode is selected according to the load condition, the chip area is increased due to additional circuit for mode control and the optimum efficiency cannot be achieved around the mode transition point. To solve such problems, a new integrated control method is proposed in this paper, in which a PLL is used in the current mode PWM control circuit instead of an oscillator. The proposed integrated control method is verified through a design of a buck converter using PSIM simulation. Simulation of the complete buck converter circuit by Cadence Spectre showed a maximum efficiency of 94.7% at a load current of 250mA and an efficiency of 85.4% at a load current of 10mA under the light load condition.

• Women's Health Nursing
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• v.18 no.1
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• pp.38-48
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• 2012

Purpose: This study described female college students' knowledge, self-efficacy and health behaviors related to bone health. Methods: A descriptive cross-sectional survey design was used. A total of 214 students were conveniently recruited from a school of nursing in Korea. Participants (mean age=21.2, SD=1.9 years) bone mineral density (BMD) was measured using dual energy x-ray absorptionmetry. Participants also completed a questionnaire consisting of knowledge test, self-efficacy scale and health behaviors related to bone health. Data were analyzed using SPSS/WIN 17.0 program. Results: The mean BMD at left femoral neck site was $0.86g/cm^2$ and 6.1~12.6%. Results showed that participants were below the expected range of BMD. Level of knowledge (correct rate=54%) and self-efficacy were moderate (mean 54.8 out of 84). More than 84% of subjects drank alcohol more than once a month and 58.4% did participate in regular exercise. Only 7.9% participants took calcium and vitamin-D rich foods every day. There were significant positive correlations between knowledge and self-efficacy (r=.17), health behaviors (r=.14) and self-efficacy and health behaviors (r=.28, all p<.05). Conclusion: These results suggest that health care professionals need to provide effective interventions for young women in order to enhance knowledge, self-efficacy and health behaviors related to bone health.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.3
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• pp.135-145
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• 2011

Accurate process characterization and optimization are the first step for a successful advanced process control (APC), and they should be followed by continuous monitoring and control in order to run manufacturing processes most efficiently. In this paper, process characterization and recipe optimization methods with multiple outputs are presented in high density plasma-chemical vapor deposition (HDP-CVD) silicon dioxide deposition process. Five controllable process variables of Top $SiH_4$, Bottom $SiH_4$, $O_2$, Top RF Power, and Bottom RF Power, and two responses of interest, such as deposition rate and uniformity, are simultaneously considered employing both statistical response surface methodology (RSM) and neural networks (NNs) based genetic algorithm (GA). Statistically, two phases of experimental design was performed, and the established statistical models were optimized using performance index (PI). Artificial intelligently, NN process model with two outputs were established, and recipe synthesis was performed employing GA. Statistical RSM offers minimum numbers of experiment to build regression models and response surface models, but the analysis of the data need to satisfy underlying assumption and statistical data analysis capability. NN based-GA does not require any underlying assumption for data modeling; however, the selection of the input data for the model establishment is important for accurate model construction. Both statistical and artificial intelligent methods suggest competitive characterization and optimization results in HDP-CVD $SiO_2$ deposition process, and the NN based-GA method showed 26% uniformity improvement with 36% less $SiH_4$ gas usage yielding 20.8 ${\AA}/sec$ deposition rate.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.68-78
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• 2012

A layout of an LNG FPSO should be elaborately determined as compared with that of an onshore plant because many topside process systems are installed on the limited area; the deck of the LNG FPSO. Especially, the layout should be made as multi-deck, not single-deck and have a minimum area. In this study, a multi-floor layout for the liquefaction process, the dual mixed refrigerant(DMR) cycle, of LNG FPSO was determined by using the optimization technique. For this, an optimization problem for the multi-floor layout was mathematically formulated. The problem consists of 589 design variables representing the positions of topside process systems, 125 equality constraints and 2,315 inequality constraints representing limitations on the layout of them, and an objective function representing the total layout cost. To solve the problem, a hybrid optimization method that consists of the genetic algorithm(GA) and sequential quadratic programming(SQP) was used in this study. As a result, we can obtain a multi-floor layout for the liquefaction process of the LNG FPSO which satisfies all constraints related to limitations on the layout.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.216-220
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• 2006

One of the approaches for reducing the size of the quarter wavelength monopole antenna is the helix and the stacked structure. This paper presents a formula for the relationship between the geometrical parameter and the operating frequency of a slacked helix chip antenna. The stacked helix chip antenna was designed for PCS/IMT-2000 dual-bands operation. The fabricated antenna uses an FR-4 substrate with relative permittivity of 4.2, and its dimensions are $15{\times}7.5{\times}0.4mm^3$. The measured impedance bandwidth (VSWR<2) is 400MHz at the operating frequency.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.85-92
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• 2017

PURPOSE. The aim of this study was to evaluate the effect of tooth surface pre-treatment steps on shear bond strength, which is essential for understanding the adhesive cementation process. MATERIALS AND METHODS. Shear bond strengths of different cements with various tooth surface treatments (none, etching, priming, or etching and priming) on enamel and dentin of human teeth were measured using the Swiss shear test design. Three adhesives (Permaflo DC, Panavia F 2.0, and Panavia V5) and one self-adhesive cement (Panavia SA plus) were included in this study. The interface of the cement and the tooth surface with the different pre-treatments was analyzed using SEM. pH values of the cements and primers were measured. RESULTS. The highest bond strength values for all cements were achieved with etching and primer on enamel ($25.6{\pm}5.3-32.3{\pm}10.4MPa$). On dentin, etching and priming produced the highest bond strength values for all cements ($8.6{\pm}2.9-11.7{\pm}3.5MPa$) except for Panavia V5, which achieved significantly higher bond strengths when pre-treated with primer only ($15.3{\pm}4.1MPa$). Shear bond strength values were correlated with the micro-retentive surface topography of enamel and the tag length on dentin except for Panavia V5, which revealed the highest bond strength with primer application only without etching, resulting in short but sturdy tags. CONCLUSION. The highest bond strength can be achieved for Panavia F 2.0, Permaflo DC, and Panavia SA plus when the tooth substrate is previously etched and the respective primer is applied. The new cement Panavia V5 displayed low technique-sensitivity and attained significantly higher adhesion of all tested cements to dentin when only primer was applied.