• Structural Engineering and Mechanics
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• 제70권6호
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• pp.765-779
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• 2019

Most of the existing evaluation criteria of vibration serviceability rely on the peak acceleration of the structure rather than that of the people keeping their own body unmoved on the structure who is the real receiver of structural vibrations. In order to accurately assess the vibration serviceability, therefore, a full path assessment approach of vibration serviceability based on vibration source, path and receiver is not only tentatively proposed in this paper, taking the peak acceleration of receiver into account, but also introduce a probability procedure to provide more instructive information instead of a single value. In fact, semi-rigid supported on both sides of the structure is more consistent with the actual situation than simply supported or clamped due to the application of the prefabricated footbridge structures. So, the footbridge is regarded as a beam with semi-rigid supported on both sides in this paper. The differential quadrature-integral quadrature coupled method is not only to handle different type of boundary conditions, but also after being further modified via the introduction of an approximation procedure in this work, the time-varying system problem caused by human-structure interaction can be solved well. The analytical results of numerical simulations demonstrate that the modified differential quadrature-integral quadrature coupled method has higher reliability and accuracy compared with the mode superposition method. What's more, both of the two different passive control measures, the tuned mass damper and semi-rigid supported, have good performance for reducing vibrations. Most importantly, semi-rigid supported is easier to achieve the objective of reducing vibration compared with tuned mass damper in design stage of structure.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7507-7512
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• 2015

Background: In the low incoming country Bangladesh, breast cancer is second most common neoplasm and is increasing at an alarming rate among females. Lack of awareness and illiteracy are contributory factors for late presentation and therefore mortality. Purpose: To examine associations of different factors with breast cancer mortality and to raise awareness among the women of society in Bangladesh. Materials and Methods: This descriptive case-control study was conducted on 160 participants from April 2011 till July 2014. Through a valid questionnaire covering personal and family history, data were collected by face to face interview. For analyzing correlations among factors with breast cancer data, binary logistic regression, Pearson's ${\chi}^2$-value, odd ratios and p-value tests were conducted with SPSS version 20. Results: The mean age of the patients was 43.0 ($SD={\pm}11.12$). In ascending order the leading significant factors were hormone therapy (p<0.0000, OR=4.897), abortion (p<0.0001, OR=3.452), early start menarche (p<0.0002, OR=3.500), family history (p<0.0022, OR=3.235), and late menopause (p<0.0093, OR=3.674) with both ${\chi}^2$ test and logistic regression analyses. Non-significant factors were cancer experience, fatty food habits, marital status and taking alcohol. Conclusions: Regarding the investigation of this study, significant and insignificant factor's correlation visualization with breast cancer will be helpful to increase awareness among Bangladeshi women as well as all over the world.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.840-845
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• 2017

In this paper, in order to investigate the lifetime of oil-paper insulation, specimens were artificially aged with thermal and electrical multiple stresses. Accelerated ageing factors and equivalent operating years for each aging temperatures were derived from results of tensile strengths for the aged paper specimens. Also, the evaluation for the multi-stress aged specimens were carried out through the measurement of impulse breakdown voltage at high temperature of $85^{\circ}C$. The lifetimes of the oil-paper insulations were calculated with the value of 66.7 for 1.0 mm thickness specimens and 69.7 for 1.25 mm thickness specimens throughout the analysis of impulse BD voltages using equivalent operating years, which means that dielectric strengths would not be severely decreased until the mechanical lifetime limit. Therefore, for the lifetime evaluation of the oil-paper insulation, thermal aging would be considered as a dominant factor whereas electrical degradation would be less effective.

• 한국환경복원기술학회지
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• 제12권2호
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• pp.50-60
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• 2009

A spatial decision making process is needed when a local government tries to make polices and plans for eco-tourism in urban and regional site scale. This study aimed to suggest an assessment model to support spatial decision making on planning and making polices for eco-tourism. The model composes 6 stages of 'setting up ecogeographic territories'. 'value analysis method as ecotourism resources' 'synthetic assessing', 'grading values', 'selecting main resources for ecotourism' and 'spatial decision making support'. Applying the model to Shiheung city in Kyounggi province, validity was secured. By using the model, it was possible to make some decisions effectively such as selection of ecotourism resources, decision of the priorities of polices for ecotourism, and setting up the type of ecotourism to be introduced. In addition, by visualizing high valued resources and areas for ecotourism it w possible to support to make plans and policies effectively.

• 한국환경복원기술학회지
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• 제8권6호
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• pp.80-91
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• 2005

This research aims to classify wetland types and evaluate functions of a dam lake. The case study area is Boryung lake in Boryung City. In this study was carried out based upon field surveys, drawing maps and publication, and modified-RAM which can evaluate the general functions and conservation values of wetlands. Eight functions of 2-12 variables each are analyzed for assessing the wetland functions. The analysis shows that several types of wetlands were identified, such as Palustrine/ Perennial/ Hydrophytes, Palustrine/ Perennial/ Openwater, Palustrine/ Seasonal/ Herbal, Palustrine/ Seasonal/ Shrub and Scrub, Palustrine/ Seasonal/ Hydrophye, and Riparian/ Seasonal/ Shrub in the Boryung lake. The average level of functions of the wetlands is very "HIGH", and it is recommended that prompt conservation measures should be taken.

• 한국IT서비스학회지
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• 제11권1호
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• pp.239-246
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• 2012

The user increases around the WiBro and in which the mobile broad band service is the wireless internet base technology HSDPA, that is the cellular phone foundation technique, and moreover the issue about the user effective quality guarantee emerges but the quality control of the wireless network is the incomplete actual condition. Therefore, the reliability verification according to the development of the system for the performance measure for the continued wireless data service and it and evaluation are needed for the quality control. In this paper, the wireless data service quality measurement system was implemented with the design. The same test environment as the existing network performance measurement program was built for the reliability verification of the embodied device for measuring quality and evaluation and the cost performance was performed. It could confirm that design and embodied wireless data service quality measurement system operated accurately in this paper through the quality measure result value analysis.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.134-137
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• 2005

In this paper, a continuous contact treatment has been considered during FE-analysis of the sheet metal forming processes. Because the simulation is usually performed stepwise, the status of contact can change suddenly. In case of implicit scheme, the increment of punch stroke can be chosen as large value. For exact assessment of contact force and friction force between die and sheet, the continuous contact treatment is proposed. The virtual surface of sheet metal is modeled by NURBS curves or surfaces in order to calculate exact contact area and penetration depth. From the geometrical evaluation of contact behavior, additional contact pressure is imposed to the element. The deformation of bending process and hydroforming process are analyzed based on this scheme.

• Smart Structures and Systems
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• 제29권3호
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• pp.475-484
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• 2022

The loss of cable tension for civil infrastructure reduces structural bearing capacity and causes harmful deformation of structures. Currently, most of the structural health monitoring (SHM) approaches for cables rely on contact transducers. This paper proposes a cable tension identification technology using percussion sound, which provides a fast determination of steel cable tension without physical contact between cables and sensors. Notably, inspired by the concept of tensioning strings for piano tuning, this proposed technology predicts cable tension value by deep learning assisted classification of "percussion" sound from tapping a steel cable. To simulate the non-linear mapping of human ears to sound and to better quantify the minor changes in the high-frequency bands of the sound spectrum generated by percussions, Mel-frequency cepstral coefficients (MFCCs) were extracted as acoustic features to train the deep learning network. A convolutional neural network (CNN) with four convolutional layers and two global pooling layers was employed to identify the cable tension in a certain designed range. Moreover, theoretical and finite element methods (FEM) were conducted to prove the feasibility of the proposed technology. Finally, the identification performance of the proposed technology was experimentally investigated. Overall, results show that the proposed percussion-based technology has great potentials for estimating cable tension for in-situ structural safety assessment.

• 한국환경보건학회지
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• 제44권3호
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• pp.283-292
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• 2018

Objectives: This study was conducted to identify hazardous factors that reflect the characteristics of the academy and to provide basic data of environmental safety standard. Methods: Heavy metals, volatile organic compounds, formaldehyde, pesticides and phthalates were measured in 20 academies, which were supplementary, music, art and physical education institutes. Results: In case of heavy metals, the 12 locations were detected for lead (Pb) over the standard value, and 15 locations were exceeded for the total heavy metal. In six locations, the concentrations of volatile organic compounds were exceeded the standard value of $400{\mu}g/m^3$, and two locations for formaldehyde were exceeded the standard value of $100{\mu}g/m^3$. The most commonly detected agents in the air dust were chlorpyrifos and diazinon. The concentrations of DEHP, DINP, and DBP were detected and exceeded in several academies, The risk assessment results showed that HCHO as carcinogen had a safety level of 10-7 to 10-6, and DEHP and DINP as non-carcinogens had a safety level as assessed to be under than 0.1. Conclusions: Through the investigation of long-term environmental and health effects related laws on academies, indoor air quality management might be needed because there were cases of exceeding standard.

• 환경영향평가
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• 제32권5호
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• pp.269-278
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• 2023

서울 도심에 있는 어린이 모래 놀이터의 안전한 사용을 확인하기 위해 토양 중금속(Cd, Cu, As, Pb, Zn, Ni, Hg, Cr⁶⁺) 오염현황을 조사하였다. 시료 채취 장소는 서울시 7개 자치구에서 281개소를 선정하였다. 본 연구에서 중금속의 전체 평균 농도는 Cd 0.21 mg/kg, Cu 5.97 mg/kg, As 2.40 mg/kg, Pb 7.55 mg/kg, Zn 34.08 mg/kg, Ni 4.22 mg/kg, Hg 0.02 mg/kg였다. Cr⁶⁺은 불검출되어, 이를 포함하는 중금속 7종 모두 토양오염우려기준 1 지역 기준보다 낮은 것으로 나타났다. 아울러 토양오염등급(SPC)을 평균값으로 평가했을 경우에 7개 자치구 모든 지점에서 1등급인 100 미만인 것으로 나타나 건전한 토양 상태임을 보였다. 하지만 최대값으로 평가했을 경우 5개 자치구에서 일부 100 이상의 값을 나타내었다. 따라서 안전한 토양환경을 위하여 어린이 놀이터의 관리주체인 지자체의 지속적인 관리와 관심이 필요한 것으로 보인다.