• Ocean Systems Engineering
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• v.8 no.1
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• pp.41-55
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• 2018

Accidental oil and gas leak is a critical concern for the offshore industry because it can lead to severe consequences and as a result, it is imperative to evaluate the probabilities of occurrence of the consequences of the leakage in order to assess the risk. Event Tree Analysis (ETA) is a technique to identify the consequences that can result from the occurrence of a hazardous event. The probability of occurrence of the consequences is evaluated by the ETA, based on the failure probabilities of the sequential events. Conventional ETA deals with events with crisp failure probabilities. In offshore applications, it is often difficult to arrive at a single probability measure due to lack of data or imprecision in data. In such a scenario, fuzzy set theory can be applied to handle imprecision and data uncertainty. This paper presents fuzzy ETA (FETA) methodology to compute the probability of the outcomes initiated due to oil/gas leak in an actual offshore-onshore installation. Post FETA, sensitivity analysis by Fuzzy Weighted Index (FWI) method is performed to find the event that has the maximum contribution to the severe sequences. It is found that events of 'ignition', spreading of fire to 'equipment' and 'other areas' are the highest contributors to the severe consequences, followed by failure of 'leak detection' and 'fire detection' and 'fire water not being effective'. It is also found that the frequency of severe consequences that are catastrophic in nature obtained by ETA is one order less than that obtained by FETA, thereby implying that in ETA, the uncertainty does not propagate through the event tree. The ranking of severe sequences based on their probability, however, are identical in both ETA and FETA.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.818-823
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• 2016

Millimeter wave (mm-wave) communication systems provide high data rates owing to the large bandwidths available at mm-wave frequencies. Recently, analogue and digital combined beamforming, namely "hybrid beamforming" has drawn attentions owing to its ability to realize the required link margins in mm-wave systems. Taking into account the radio frequency (RF) hardware limitations, such as the analogue phase shifter gain constraint and the low resolution of the phase controller, we introduce an uplink hybrid beamforming system that includes discrete Fourier transform (DFT) based "fixed" analogue beamforming. We adopt a zero-forcing (ZF) multiple-input multiple-output (MIMO) equalizer to eliminate the uplink inter-user interferences. Moreover, to improve the sum-rate performances, we propose a transmit beam selection algorithm which makes the uplink effective channels, i.e., the beamformed channels, become near orthogonal. The effectiveness of the proposed beam selection algorithm was verified through numerical simulations.

• Journal of the Korean Dietetic Association
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• v.26 no.2
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• pp.153-173
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• 2020

The purpose of this study was to objectively quantify the effects of nutrition and dietary life education on preschoolers through meta-analysis. In addition, it provides basic data for the implementation of nutrition education and development of systematic nutrition and dietary life education programs. In this study, a meta-analysis of 27 papers was conducted that conformed to the selection criteria in the study conducted from January 2012 to August 2019 to derive objective data on the effects of education. As a result of the analysis, the overall effective size of nutrition and dietary life education for preschoolers was 0.829, which indicates a strong effect. According to the education method, the effect size of general education was 0.562, which indicates a medium effect size, the vegetable playing-based experience education was 0.685, which indicates a medium effect size, and cooking activity-based experience education was 1.101, which indicates a large effect size. Judging from this result, experience activity education was more effective than general nutrition education. In addition, the combined size of convergence education conducted through a combination of general and experience education was found to be the most effective at 1.301. In terms of educational effect, it was confirmed that the effect size was 0.898 for improving nutrition knowledge, 0.858 for improving dietary habits, 0.836 for improving unbalanced diet, and 0.756 for improving food preference and intake, and the sizes of effects were all found to be large. As frequency of education increased, the number of education participants decreased and the effect of education increased.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2403-2407
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• 2013

The hybrid density-functional (B3LYP/6-31G(d,p)) method was used to analyze the substitution effect on the $C_{20}H_{20}$ cage based on calculation of the frontier orbitals of fifteen $C_{20}H_{17}(OH)_3$ derivatives. All substitution products were geometrically optimized without constraints and confirmed by frequency analysis. The results suggest that the cis-1 cis-1 cis-2 regioisomer is the most stable isomer, which implies that hydrogen bonding exerts a stronger effect on the relative energies of the trihydroxide than long-range interactions. Thus, this supports the experimental result in which the bisvicinal tetrol was of particular preparative-synthetic interest. While the LUMO of each of the $C_{20}H_{17}(OH)_3$ regioisomers was equivalently delocalized over the void within the cage, the HOMO was limitedly delocalized on substituents and carbons in close proximity to the substituents. The characteristics of the HOMO of each of the regioisomers vary based on the substitution sites. This indicates that the 15 regioisomers of each $C_{20}H_{20}$ trisubstituted derivative might undergo an entirely different set of characteristic chemical reactions with electrophilic reagents. The results further suggest that the penta-substituted OH groups on the surface of the fullerene cage are more likely to be localized on a pentagon than to be homogeneously delocalized.

• Journal of the Speleological Society of Korea
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• no.92
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• pp.31-40
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• 2009

The purpose of this study was to revitalize management of Hapki-do gymnasium based on customer. The Subjects of this study were 264 persons who have trained Hapki-do. Also, subjects were chosen by convenience sampling method. Data were analized with SPSS 12.0 version for frequency and crosstab analysis. Following is the analysis result. First of all, it is necessary repairing facilities and operating systematic education program. Secondly, it is necessary a discriminatory education program. Further study on demand features of Hapkido gymnasiums will contribute to expand and to strengthen the base of Hapkido development. This will aid Hapkido to gain dominant position in the competition of martial arts and sports industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.626-632
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• 2003

In this paper, forward-wave -3㏈ directional coupler with finite-thickness conductor and asymmetrical coupled lines are designed and experimentally verified using mode-matching based design methodology. Most of studies published in the literatures about the coupled lines are mainly concentrated on the adjustment of coupling amount by changing various geometric configurations. The analysis results in this paper show that thicker metalization requires reduced coupler length in the forward-wave directional coupler composed of asymmetrical coupled lines. Several forward-wave directional -3 ㏈ couplers with finite metalization thickness composed of asymmetrical coupled microstrip lines have been designed in the 5 ㎓ based on proposed design method. The measured data show -4.05㏈∼-4.09㏈ coupling at center frequency which is very closed to design value. The tight coupling has been implemented with accurate design methodology which take mentalization thickness into account.

• Journal of the Korean Institute of Educational Facilities
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• v.27 no.2
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• pp.69-78
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• 2020

Interest in the school environment design is increasing as the project to restructure school space and to become common in school through smart devices. However, no research has been presented on the current status of studies on school environmental design, and the need for analysis of recent research trends in school environmental design is required. In response, this study aims to provide basic data on school environmental design by analysing the trends of domestic studies of school environmental design since 2010 and to present the direction of research on future school environmental design. A total of 312 papers related to school architecture and spatial design are set for study in the results of academic information search on school environmental design. Based on this, frequency analysis and cross-sectional analysis are conducted based on the classification table according to the year of issue, research subject, research purpose, and research method. The statistical significance of the research subjects was secured in accordance with the year of issue and subject to study, and accordingly the key research key words were derived. It is meaningful that through this study, the current status of school environmental design research over the last 10 years can be analyzed and the direction for the future school environmental design research has been suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.676-682
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• 2014

In this paper, precipitation echo(PRE) and non-precipitaion echo(N-PRE)(including ground echo and clear echo) through weather radar data are identified with the aid of neuro-fuzzy algorithm. The accuracy of the radar information is lowered because meteorological radar data is mixed with the PRE and N-PRE. So this problem is resolved by using RBFNN and judgement module. Structure expression of weather radar data are analyzed in order to classify PRE and N-PRE. Input variables such as Standard deviation of reflectivity(SDZ), Vertical gradient of reflectivity(VGZ), Spin change(SPN), Frequency(FR), cumulation reflectivity during 1 hour(1hDZ), and cumulation reflectivity during 2 hour(2hDZ) are made by using weather radar data and then each characteristic of input variable is analyzed. Input data is built up from the selected input variables among these input variables, which have a critical effect on the classification between PRE and N-PRE. Echo judgment module is developed to do echo classification between PRE and N-PRE by using testing dataset. Polynomial-based radial basis function neural networks(RBFNNs) are used as neuro-fuzzy algorithm, and the proposed neuro-fuzzy echo pattern classifier is designed by combining RBFNN with echo judgement module. Finally, the results of the proposed classifier are compared with both CZ and DZ, as well as QC data, and analyzed from the view point of output performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.551-561
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• 2014

Since the depth and texture images have been widely used for generating 3-dimensional stereoscopic image, the security of them have been focused. In this paper, we propose a new watermarking technique for copyright of stereo and multiview images which is generated in an arbitrary viewpoint by depth and texture image. After the mark space is selected for preserving watermark through DIBR (depth-image-based rendering) process which uses 3D warping, the texture image is transformed to the frequency coefficient using 2D DCT (discrete cosine transform). Some parts of them are quantized, which is the corresponding process to watermarking. The embedded watermark is not conformed by eyes, so we identified the invisibility of the proposed method. In case of appling attacks of general image process, we also identified the robustness of it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.450-460
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• 2017

T wave is cardiac parameters that represent ventricular repolarization, it is very important to diagnose arrhythmia. Several methods for detecting T wave have been proposed, such as frequency analysis and non-linear approach. However, detection accuracy is at the lower level. This is because of the overlap of the P wave and T wave depending on the heart condition. We propose T wave detection algorithm based on target area extraction through QRS cancellation and moving average. For this purpose, we detected Q, R, S wave from noise-free ECG(electrocardiogram) signal through the preprocessing method. And then we extracted P, T target area by applying decision rule for four PAC(premature atrial contraction) pattern another arrhythmia through moving average and detected T wave using RT interval and threshold of RR interval. The performance of T wave detection is evaluated by using 48 record of MIT-BIH arrhythmia database. The achieved scores indicate the average detection rate of 95.32%.