• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.190-198
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• 2009

This study shows the developing process of the risk assessment models for railway casualty accidents. To evaluate the risks of these accidents, the hazardous events and the hazardous factors were identified by the review of the accident history and engineering interpretation of the accident behavior. The frequency of each hazardous event was evaluated from the historical accident data and structured expert judgments by using the Fault Tree Analysis (FTA) technique. In addition, to assess the severity of each hazardous event, the ETA (Event Tree Analysis) technique and other safety techniques were applied. The risk assessment models developed can be effectively utilized in defining the risk reduction measures in connection with the option analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.3
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• pp.141-150
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• 2014

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

• Journal of the Korean Society of Costume
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• v.67 no.3
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• pp.31-46
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• 2017

The purpose of this study is to analyse the occurrence and evolution of Mao suit which is important position in the modern costume history of China and to provide a source of design inspiration to contemporary fashion designers. In the research method, literature review and case studies was conducted in parallel. For the literature review, changes of Mao suit in each age were reviewed with reference to the related documents, Chinese costume and cultural history, prior research papers and internet resources. The case analysis was qualitatively done focusing on the silhouette, color and detail of clothes in fashion collections. The scope of the study was from 1912 to 2000. The case analysis of the Mao suit applied to the contemporary fashion was made on the applications centered around 'London Collection', 'New York Collection', 'Paris Collection', 'Milan Collection' and 'Chinese Fashion Week' from 2008 to 2015. The results found that Mao suit changed into many different forms after Sun Wen designed it for the first time in 1912. This study classified it into Phase 1(1912~1927), Phase 2(1928~1965), Phase 3(1966~1977), and Phase 4(1978~2000) with historical and political issues and conformational changes in Mao suit. The frequency analysis of the cases of the fashion collections using Mao suit from 2008 to 2015 showed an increased application of Mao suit to the western collection in New York, Paris and London in 2008 due to the impact of Beijing Olympics. However, from 2009 onwards, the frequency of the utilization of Mao suit was higher in the Chinese Fashion Week and the New York Collection. This cause is explained by the fact that the designers who inspired from Mao suit in the New York Collection are American Chinese.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.26-35
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• 2007

The vehicle of urban transit is a complex system that consists of various electric, electronic, and mechanical equipments, and the maintenance cost of this complex and large-scale system generally occupies sixty percent of the LCC (Life Cycle Cost). For reasonable establishing of maintenance strategies, safety security and cost limitation must be considered at the same time. The concept of system reliability has been introduced and optimized as the key of reasonable maintenance strategies. For optimization, three preceding studies were accomplished; standardizing a maintenance classification, constructing RBD (Reliability Block Diagram) of VVVF (Variable Voltage Variable Frequency) urban transit, and developing a web based reliability evaluation system. Historical maintenance data in terms of reliability index can be derived from the web based reliability evaluation system. In this paper, we propose applying inverse problem analysis method and hybrid neuro-genetic algorithm to system reliability optimization for using historical maintenance data in database of web based system. Feed-forward multi-layer neural networks trained by back propagation are used to find out the relationship between several component reliability (input) and system reliability (output) of structural system. The inverse problem can be formulated by using neural network. One of the neural network training algorithms, the back propagation algorithm, can attain stable and quick convergence during training process. Genetic algorithm is used to find the minimum square error.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.336-345
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• 2023

Background: The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy. Methods: This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups. Results: Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy. Conclusion: The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.152-152
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• 2022

Only employing historical data limits the estimation of the full distribution of probable Tropical Cyclone (TC) risk due to the insufficiency of samples. Addressing this limitation, this study introduces a semi-physical TC rainfall model that produces spatially and temporally resolved TC rainfall data to improve TC risk assessments. The model combines a statistical-based track model based on the Markov renewal process to produce synthetic TC tracks, with a physics-based model that considers the interaction between TC and the atmospheric environment to estimate TC rainfall. The simulated data from the combined model are then fitted to a probability distribution function to compute the spatially heterogeneous risk brought by landfalling TCs. The methodology is employed in South Korea as a case study to be able to implement a country-scale-based vulnerability inspection from damaging TC impacts. Results show that the proposed model can produce TC tracks that do not only follow the spatial distribution of past TCs but also reveal new paths that could be utilized to consider events outside of what has been historically observed. The model is also found to be suitable for properly estimating the total rainfall induced by landfalling TCs across various points of interest within the study area. The simulated TC rainfall data enable us to reliably estimate extreme rainfall from higher return periods that are often overlooked when only the historical data is employed. In addition, the model can properly describe the distribution of rainfall extremes that show a heterogeneous pattern throughout the study area and that vary per return period. Overall, results show that the proposed approach can be a valuable tool in providing sufficient TC rainfall samples that could be an aid in improving TC risk assessment.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.335-343
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• 2007

Drought characteristics need to be preceded before establishing a drought mitigation plan. In this study, using a Standardized Precipitation Index (SPI), a hydrologic drought was defined as an event during which the SPIs are continuously below a certain truncation level. Then, a methodology of drought frequency analysis was performed to quantitatively characterize droughts considering drought duration and severity simultaneously. The theory of runs was used to model drought recurrence and to determine drought properties like duration and severity. Short historical records usually do not allow reliable bivariate analyses. However, more than hundred years of precipitation data (1770 ${\sim}$ 1907) collected in Chosun Kingdom Age using an old Korean rain gage called Chukwooki can provide valuable information about past events. It is shown that a bivariate gamma distribution well represented the joint probabilistic properties of Korean drought duration and severity. The overall results of this study show that the proposed bivariate drought frequency analysis overcomes the drawbacks of the conventional univariate frequency analysis by providing a consistent representation of the drought recurrent property.

• Wind and Structures
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• v.33 no.6
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• pp.423-435
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• 2021

Although existing algorithms can predict wind speed using historical observation data, for engineering feasibility, most use moment methods and probability density functions to estimate fitted parameters. However, extreme wind speed prediction accuracy for long-term return periods is not always dependent on how the optimized frequency distribution curves are obtained; long-term return periods emphasize general distribution effects rather than marginal distributions, which are closely related to potential extreme values. Moreover, there are different wind speed parent sample types; how to theoretically select the proper extreme value distribution is uncertain. The influence of different sampling time intervals has not been evaluated in the fitting process. To overcome these shortcomings, updated steps are introduced, involving parameter sensitivity analysis for different sampling time intervals. The extreme value prediction accuracy of unknown parent samples is also discussed. Probability analysis of mean wind is combined with estimation of the probability plot correlation coefficient and the maximum likelihood method; an iterative estimation algorithm is proposed. With the updated steps and comparison using a Monte Carlo simulation, a fitting policy suitable for different parent distributions is proposed; its feasibility is demonstrated in extreme wind speed evaluations at Longhua and Chuansha meteorological stations in Shanghai, China.

• The Research Journal of the Costume Culture
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• v.16 no.1
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• pp.1-21
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• 2008

The purpose of this study is to typify femininity and masculinity represented in mainstream women's and men's fashion magazines in Korea since 2000 and infer sexual ideology appearing in contemporary Korean society by content analysis with the view of plural sexuality. For the content analysis total 259 editorial fashion photography was analyzed. As the result, 5 femininities and 5 masculinities were typified, and then sexual discourse was inferred out of the frequency of each type and texts with the images. On the basis of previous studies and historical considerations of this topic, the types of sexuality represented in mainstream fashion magazines in Korea since 2000 were classified as follow.: in women's fashion magazines Traditional Femininity and Androgynous Femininity were almost similarily dominant sexuality, and Glamor Femininity, Babydoll Femininity, and Genderless sexuality were alternative. Meanwhile, in men's fashion magazines Traditional Masculinity formed clear dominant sexuality, and Macho Masculinity, Androgynous Masculinity, Adolescent Masculinity, and Genderless sexuality were alternatives. In addition, Androgynous Masculinity in women's fashion magazines occupied the highest frequency, while Glamor Femininity in men's fashion magazines did so. From this sexual discourses represented in mainstream fashion magazines in Korea since 2000 are as follow.: First, mainstream fashion in Korea sticks to the modern values preserving traditional sexual ideology even in this postmodern period of the former 21C. Second, Androgynous Femininity as another dominant femininity with Traditional Femininity connotes the change of conception of femininity in Korean society. Third, Androgynous Masculinity to females is preferred, while femininity to males is still regarded as fetish or adorned object. Fourth, the appearance of various alternative sexualities leads to pluralization of sexuality, and then fashion gradually codifies youthfulness and feminine values, such as body and sexual desire more than before.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.5
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• pp.726-739
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• 2010

This study investigates and compares the changes in ethnic fashion presented over a 30-year period to understand the diversity of ethnic trends according to historical trends. Data were collected from 59 volumes of "Vogue" magazine for January and July in each year from 1980 to 2009. The data used for content analysis consists of 407 words and these were condensed into three periods according to the decade (1980-1989, 1990-1999, and 2000-2009). The selected words were classified into five sub-themes according to previous research definitions such as Asian look, European look, American look, African look, and Oceanic look. The results are as follows. First, ethnic fashion was highly presented in the 1990s and 1980s, and decreased in the 2000s; of note is that the Asian look appeared more in the 1990s. Second, ethnic fashion showed a higher frequency of F/W seasons in the 1980s and S/S seasons in the 2000s, while both seasons had a higher frequency in the 1990s. The sub-themes of coexistence were presented 26seasons out of 59 seasons. The coexistence of the Asian-European look was evident in the 1980s and 2000s, while the sub-themes coexistence was more diverse in the 1990s. Third, the words selected from sub-themes of ethnic fashion demonstrated the differences by decade. In particular, various fabrics and patterns appeared in the 1990s.