• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.2 s.17
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• pp.1-8
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• 2005

Microwave tomographic imaging technology using a bi-focusing operator has been developed in order to detect the internal voids/objects inside concrete structures. The imaging system consists of several cylindrical or planar array antennas for transmitting and receiving signals, and a numerical focusing operator is applied to the external signals both in transmitting and in receiving fields. In this study, the authors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars or dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna way was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. Numerical simulation demonstrated that a sub-surface image can be successfully reconstructed by using the proposed tomographic imaging technology. For the experimental verification, a prototype antenna array was fabricated and tested on a concrete specimen.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.80-87
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• 2011

In this paper we present subject region-based auto-focusing algorithm using noise robust focus measure. The proposed algorithm automatically estimates the main subject using entropy and solves the traditional problems with a subject position or high frequency component of background image. We also propose a new focus measure by analyzing the discrete cosine transform coefficients. Experimental results show that the proposed method is more robust to Gaussian and impulse noises than the traditional methods. The proposed algorithm can be applied to Pan-tilt-zoom (PTZ) cameras in the intelligent video surveillance system.

• Korean Journal of Acupuncture
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• v.34 no.4
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• pp.251-264
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• 2017

Objectives : To identify the prevalence and types of spin in randomised controlled trials(RCTs) of obesity with statistically non-significant results for primary outcomes to provide adequate reporting directions. Methods : Spin is specific reporting strategy that could lead the readers to misinterpret the results of RCTs. RCTs on obesity with statistically non-significant primary outcomes published from July 2015 to June 2016 were retrieved from PubMed. All included RCTs were classified into 3 intervention categories. The identification and classification of spin in the included articles was performed by two independent researchers. Results : Among 46 RCTs with statistically non-significant primary outcomes, 32 studies were assessed as having at least one spin in title, abstract or main text. Of these, 9 articles were on complementary and alternative medicine, 7 on western medicine and 16 on dietary supplement and exercise. The frequency of spin among the types of interventions was similar. The most common type of spin was 'focusing on statistical significance within-group comparison' in results section of abstract and main text, and 'focusing only on treatment effectiveness with no consideration of statistical significance' in conclusion section of abstract and main text. Studies where random sequence generation was appropriately done was less likely to have spin. Conclusions : As a majority of obesity RCTs have spin, researchers should pay more attention to adequately interpreting and reporting statistically non-significant results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1378-1388
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• 2005

Spatial control of sound is essential to deliver better sound to the listener's position in space. As it can be experienced in many listening environments. the quality of sound can not be manifested over every Position in a hall. This motivates us to control sound in a region we select. The primary focus of the developed method has to do with the brightness and contrast of acoustic image in space. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to make two different kinds of zone - the zone of quiet and the zone of loud sound - at the same time. The other perspective of this study is on the direction of sound. It is shown that we can control the direction of perceived sound source by focusing acoustic energy in wavenumber domain. To begin with, the proposed approaches are formulated for pure-tone case. Then the control methods are extended to a more general case, where the excitation signal has broadband spectrum. In order to control the broadband signal in time domain, an inverse filter design problem is defined and solved in frequency domain. Numerical and experimental results obtained in various conditions certainly validate that the acoustic brightness, acoustic contrast, direction of wave front can be manipulated for some finite region in space and time.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.441-451
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• 2016

The purpose of this study is to analyze the trend of spatial design education focusing on creativity based on design process. In this research, the theoretical frame of design process focused on creativity was organized and the trend of creativity education study in the spatial design and other design sectors was compared and analyzed. As a result of the research, the creativity education study of spatial design analyzed such a result showed the relatively low frequency, many of studies related to formative expression of idea. On the contrary, the creativity education of other design sectors is related to overall process the most, the major contents were represented as a creativity enhancement eduction through the conversion with other sectors, the utilization of study method and theology and the utilization of IT technology. The result of this study suggests that more various attempts are required for the spatial design education and that the attempts should orient the conversion between science and art, humanity and science and the integrated access of digital and analogue.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.221-226
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• 2022

The purpose of this study is to explore the differentiated motivations of users of live commerce by focusing on the entry into untact consumption culture. In addition, we intend to verify the mediating effect of engagement in the relationship between the motivation and attitude of live commerce use. As for the research method, an online survey was conducted targeting live commerce users, and 245 valid samples were used for analysis. For data analysis, frequency analysis, exploratory factor analysis, reliability analysis, multiple regression analysis, and mediation regression analysis were performed. As a result of the analysis, the motivation for using live commerce was derived from four factors: Enjoyment of interaction, Substitutability of personal examination, Need for community, Trend setting. And Engagement was found to have a significant effect on attitude. Finally, engagement was found to have a partial mediating effect in the relationship between the motivation and attitude of live commerce use. The research results will provide implications for understanding non-face-to-face consumption culture and establishing effective strategies for the live commerce industry in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.371-380
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• 2023

Currently, as construction projects in Korea are becoming larger and more complex, the hazard rate of the construction industry is steadily increasing, contrary to other industries. This can be seen as an indication that the safety technology and safety consciousness of construction workers are insufficient compared to the improved construction technology. In addition, due to the characteristics of the construction industry based on manpower, most accidents appear in conventional forms such as fall and trip due to human errors. Therefore, analyzing the relationship between the characteristics of human resources and accidents and establishing detailed safety plans is an essential part of reducing construction accidents. In this study, a correlation analysis was conducted using 62,805 cases of construction accident cases over 3 years to derive the characteristics of accident occurrence focusing on the age of workers. As a result of the analysis, the relationship between the age of workers and the frequency and severity of accidents for each accident type was derived, focusing on the top 10 accident types.

• Journal of Convergence for Information Technology
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• v.10 no.2
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• pp.109-115
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• 2020

This study is for analyzing and verifying of impact and effect for undergraduate's leadership through the Servant Leadership curriculum. The Servant Leadership's lecture and period for this study has been done for 15th week, and 2 hours for each week. To verify the effectiveness of the Servant Leadership, we've composed 2 different groups and compared the results of the preliminary inspection and post-test, then analyzed the differences of the preliminary inspection and post-test with focusing on the research hypothesis. Statistical treatment of this study made use of the statistical program SPSS/WIN 22.0, and the method of analysis was done with factor analysis for validity verification of each factor. We used Frequency analysis like frequency and percentage about the generalities of the subject. Looking at the investigation of this research, the overalls such as the University Facilities, curriculum, professor and a school report was higher after training than before training the general programs, On the other hand, friendship and major got lower after training than before, but appeared no significant difference in the statistics. The whole leadership has appeared as heighten after education than before, through the servant Leadership's lecture Empowerment and personality were appeared as heighten after education than before, and Similarly on Human relations.

• The Journal of the Acoustical Society of Korea
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• v.33 no.5
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• pp.300-308
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• 2014

Photoacoustic imaging is a useful tool for the diagnosis of atherosclerosis because it is capable of providing anatomical and pathological information at the same time. A photoacoustic signal detector is a pivotal element to achieve high spatial resolution, so that it should have broadband spectrum with a high center frequency. Since a photoacoustic imaging probe is directly inserted into blood vessel to diagnose atherosclerosis, the total size of the photoacoustic signal detector should be less than 1 mm. The main purpose of this paper is to demonstrate that PVDF can be used as an active material for the photoacoustic signal detector with a high frequency and broadband characteristic. The photoacoustic signal detector developed in this study was a single element ultrasound transducer with an aperture of $0.5{\times}0.5mm$ and the total size of 1 mm. In the design stage, the natural focal depth was adjusted for an effective focal area to cover the region of interest, i.e., 1~5 mm in depth. This was because geometrical focusing could not be used due to the small aperture. Through a pulse-echo test, it was ascertained that the developed photoacoustic signal detector has the -6 dB bandwidth ranging between 40.1 and 112.8 MHz and the center frequency of 76.83 MHz.

• Journal of Korea Water Resources Association
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• v.48 no.12
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• pp.1011-1021
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• 2015

This study aims to investigate droughts from the magnitude perspective based on the SPI (Standardized Precipitation Index) and the theory of runs applicable to quantitative analysis of drought in South Korea. In addition, the dry spell analysis was conducted on the drought history in the five major river basins of South Korea to obtain the magnitude, duration and severity of drought, and the quantitative evaluation has been made on historical droughts by estimating the return period using the SDF (Severity-Duration-Frequency) curve gained through drought frequency analysis. The analysis results showed that the return periods for droughts at the regional and major river basin scales were clearly identified. The return periods of severe drought that occurred around the major river basins in South Korea turn out to be mostly 30 to 50 years with the years of the worst drought in terms of severity being 1988 and 1994. In particular, South Korea experienced extremely severe droughts for two consecutive years during the period between 1994 and 1995. Drought in 2014 occurred in the Han River basin and was evaluated as the worst one in terms of severity and magnitude.