• Steel and Composite Structures
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• v.25 no.4
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• pp.427-442
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• 2017

This paper presents unprecedented damped oscillation behaviours of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an innovative slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both undamped and damped eigenfrequencies and eigenmodes have been extracted using the Lancsoz method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_1
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• pp.529-536
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• 2007

Registration between image and object space is a fundamental step in photogrammetry and computer vision. Along with rapid development of sensors - multi/hyper spectral sensor, laser scanning sensor, radar sensor etc., the needs for registration between different sensors are ever increasing. There are two important considerations on different sensor registration. They are sensor invariant feature extraction and correspondence between them. Since point to point correspondence does not exist in image and laser scanning data, it is necessary to have higher entities for extraction and correspondence. This leads to modify first, existing mathematical and geometrical model which was suitable for point measurement to line measurements, second, matching scheme. In this research, linear feature is selected for sensor invariant features and matching entity. Linear features are incorporated into mathematical equation in the form of extended collinearity equation for registration problem known as photo resection which calculates exterior orientation parameters. The other emphasis is on the scheme of finding matched entities in the aide of RANSAC (RANdom SAmple Consensus) in the absence of correspondences. To relieve computational load which is a common problem in sampling theorem, deterministic sampling technique and selecting 4 line features from 4 sectors are applied.

• Journal of Korean Home Economics Education Association
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• v.10 no.2
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• pp.1-11
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• 1998

The purpose of this study is to analyze highschool girls' concerns about environmental problems after investigating the actual state of environmental education and to suggest some fundamental changes in the Home Economics classes to improve environmental education. The sample was selected form high school girl students in Kyounggi Province between September 16 and September 26, 1996. Eight hundred twenty (820) first and second grade respondents were used. The data were analyzed by frequency, mean, percentile, factor analysis. Duncan's Multiple Range Test, and Stepwise Multiple Regression. Based on the major findings, the most influential variable was parental attitudes towards environmental conservation and problem. Next in influence was the environmental education provided in Home Economics classes. Also important were the individual student's interest in Home Economics classes, and her belief in the utility of environmental conservation in everyday life. The research conclusions are as follows: 1. We'll find how to relate efficiently the environmental education with everyday life by analyzing thoroughly the text of home economics. 2. We'll develop how to educate students parents properly because parental attitudes to wards the environmental problem have a great effect on students' behaviors. 3. We'll ceinforce environmental education by developing problems, and to motivate them to take real action in the area of environmental conservation.

• The Research Journal of the Costume Culture
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• v.18 no.2
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• pp.245-260
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• 2010

Collaboration among various fields appear according to rising of snack culture, polarizing phenomenon by a point to value, consumer behavior change giving importance to direct experience, and arrival of high touch age satisfied various needs and desires of consumer. Collaboration progressed limited edition form utilizes famous artist and designer's fame to promote products and upgrade their brand image through a short period agreement. This research aims at analysis about collaboration phenomenon in collaboration manners and characteristics, and understands changed socio-cultural meaning through collaboration expressed in almost all industry for high speedy changing fashion environment. This research utilizes between theoretical study and empirical analysis. For concentrated study, research period limits from 2007 to the present time 2009. This paper's purpose is studying on the socio-cultural meaning through analysis about characteristics of the trend of collaboration expressed in contemporary fashion. This research's results are as follow as; First, common life toward aesthetic surrounding, Second, introduction of high concept, Third, the power of Homo Consmus, Forth, focusing on the intangible elements and the value. This study intends to predict change of fashion design and fashion market for complicated consumer, and present fundamental materials about fashion industry and design development of the future through consideration on concrete aspect and meaning of collaboration expressed in contemporary fashion.

• Journal of Korean Society of Rural Planning
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• v.26 no.2
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• pp.1-12
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• 2020

This study aimed to define characteristics of mountain village landscapes perceived by locals to sustainably preserve and manage mountain village landscapes. We selected landscape resources of mountain villages by reviewing previous studies and conducting field surveys and surveyed mountain villages' locals to investigate the characteristics of their perceptions of the mountain village landscapes. The surveys were conducted from March to October 2019, in the form of 1:1 questionnaire survey. In consequence, highly reliable 150 responses were analyzed. IPA method(Revised Importance-Performance Analysis) was used in the analysis. It is found that, in landscapes, the first quadrant is 'Cultivated land, Forest', the second quadrant is 'Coastal, Forestry and Agriculture Facility', the third quadrant is 'Forest Service·Profitable Facility, Settlement, History and Culture', and the fourth quadrant is 'Riparian, Street'. In conclusion, locals of mountain villages are perceiving the mountain village landscapes based on their livelihoods and daily lives, and the mountain village landscapes are closely related to their lives. The results of this study are expected to be utilized as fundamental resources in establishing policies regarding sustainable conservation and management of mountain village landscapes which led by locals.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.69-69
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• 2013

In the area of artificial photosynthesis, particularly for the generation of hydrogen form water, much attention has been paid on organic-inorganic hybrid system. Most of all, a dye/TiO2-combined system has been suggested and its potential utility was well manifested. However, due to its complicated nature of charge interactions in between dye and TiO2 -interface there remains a great challenge to establish the charge-activity relationship, per se light driven charge generation and recombination kinetics with respect to the amount of hydrogen produced. Further complexity of that hybrid system has been witnessed when sacrificial donor and aqueous media are considered. To unveil the operating mechanism on such a dye/TiO2-combined system, we have prepared organic dyes suitable to account for the effect of sacrificial donor as well as water interactions, and prepared the typical dye-grafted TiO2 films to investigate charge-activity relationship. Femtosecond flash photolysis clearly defined the dye effects anchored on to the TiO2 platform. In addition, photodynamic data contemplated well to the dye orientation proposed by the DFT calculations. Recent findings provide fundamental understanding on the dye-grafted TiO2 system and establish a firm background how future dye-sensitized organic-inorganic hybrid system can be designed for the light driven hydrogen generation from water.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.9
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• pp.1684-1697
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• 2011

We show that two protocols for RFID mutual authentication in pervasive computing environments, recently proposed by Kang et al, are vulnerable to several attacks. First, we show these protocols do not preserve the privacy of users' location. Once a tag is authenticated successfully, we show several scenarios where legitimate or illegitimate readers can trace the location of that tag without any further information about the tag's identifier or initial private key. Second, since the communication between readers and the database takes place over an insecure communication channel and in the plaintext form, we show scenarios where a compromised tag can gain access to confidential information that the tag is not supposed get access to. Finally, we show that these protocols are also vulnerable to the replay and denial-of-service attacks. While some of these attacks are due to simple flaws and can be easily fixed, others are more fundamental and are due to relaxing widely accepted assumptions in the literature. We examine this issue, apply countermeasures, and re-evaluate the protocols overhead after taking these countermeasures into account and compare them to other work in the literature.

• Structural Engineering and Mechanics
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• v.69 no.1
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• pp.21-31
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• 2019

Optimizing composite structures to exploit their maximum potential is a realistic application with promising returns. In this research, simultaneous maximization of the fundamental frequency and frequency separation between the first two modes by optimizing the fiber angles is considered. A high-fidelity design optimization methodology is developed by combining the high-accuracy of finite element method with iterative improvement capability of metaheuristic algorithms. Three powerful nature-inspired optimization algorithms viz. a genetic algorithm (GA), a particle swarm optimization (PSO) variant and a cuckoo search (CS) variant are used. Advanced memetic features are incorporated in the PSO and CS to form their respective variants-RPSOLC (repulsive particle swarm optimization with local search and chaotic perturbation) and CHP (co-evolutionary host-parasite). A comprehensive set of benchmark solutions on several new problems are reported. Statistical tests and comprehensive assessment of the predicted results show CHP comprehensively outperforms RPSOLC and GA, while RPSOLC has a little superiority over GA. Extensive simulations show that the on repeated trials of the same experiment, CHP has very low variability. About 50% fewer variations are seen in RPSOLC as compared to GA on repeated trials.

• Journal of architectural history
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• v.30 no.6
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• pp.7-22
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• 2021

This study was prepared to understand the changes in the stylobate and the characteristics of contrasting with the wooden pagoda of Hwangnyongsa Temple, which occupies an important position in ancient architecture. Literature data related to the wooden pagoda of Hwangnyongsa Temple, excavation data, and newly identified stylobate stone were examined.The reconstruction period of the wooden pagoda of Hwangnyongsa Temple, the size and form of the stylobate, the plan of the stylobate, the height plan, and the elevation plan were reviewed one after another.Since its foundation in 646, the wooden pagoda of Hwangnyongsa Temple has been rebuilt during the reign of King Gyeongmun in 873 and a stylobate has been rebuilt. Through the analysis of similar cases with the wooden pagoda's face stone members, the elevation of the stylobate was proved. It is estimated that the size and format of the wooden pagoda stylobate were similar to those of the reconstruction stylobate. It seems that the Sumijwa style stylobate was first introduced to the foundation of the wooden pagoda of Hwangnyongsa Temple. This is of great significance in that it provided a fundamental motif for the stylobate of architecture and stone architecture of the Unified Silla period.

• Earthquakes and Structures
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• v.26 no.2
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• pp.117-130
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• 2024

Probabilistic model of seismic demand is the main tool used for seismic demand estimation, which is a fundamental component of the new performance-based design method. This model seeks to mathematically relate the seismic demand parameter and the ground motion intensity measure. This study is intended to use Bayesian analysis to evaluate the accuracy of the seismic demand estimation of Steel moment resisting frames (SMRFs) through a completely Bayesian method in statistical calculations. In this study, two types of intensity measures (earthquake intensity-related indices such as magnitude and distance and intensity indices related to ground motion and spectral response including peak ground acceleration (PGA) and spectral acceleration (SA)) have been used to form the models. In addition, an extensive database consisting of sixty accelerograms was used for time-series analysis, and the target structures included five SMRFs of three, six, nine, twelve and fifteen stories. The results of this study showed that for low-rise frames, first mode spectral acceleration index is sufficient to accurately estimate demand. However, for high-rise frames, two parameters should be used to increase the accuracy. In addition, adding the product of the square of earthquake magnitude multiplied by distance to the model can significantly increase the accuracy of seismic demand estimation.