• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.1824-1831
• /
• 2009

This paper analyzes the propagation speed of the wide-area power system frequency. When a generator supplying the electric power to the grid is accidently tripped due to a disturbance on the systems, power system frequency suddenly drops during the transient period and this propagates from the location of the tripped generator to the other part of the systems like a wave. Since the propagation speed of the power system frequency depends on the own characteristics of power systems, its understanding from the perspective of the wide-area can help us in understanding power systems more correctly. In addition, the propagation speed of the power system frequency is used as a key parameter in the application study of IT based on the internet-based GPS synchronized frequency monitoring network (FENT) which has been recently implemented and operated in U.S. power systems. This paper simulates the generation trip on various locations in U.S. power systems deploying its latest dynamic model and calculates the propagation speed of the power system frequency for the application of FNET.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.6
• /
• pp.7-17
• /
• 2010

Modern construction technology has been highly systemized, which has simplified the construction methods applied to construction sites. However, on reinforced concrete construction sites, there have recently been many new disasters, and these have been bigger than before due to the heavy dependency on manpower. This study investigates the cause and cases of disasters during reinforced concrete construction. In addition, the study surveyed the psychological condition of construction site personnel in relation to the safety awareness and the causes of disasters, while deriving the basic components related to disasters on construction sites in order to analyze the relationship between each component to suggest an efficient safety management measures checklist. Construction site personnel should utilize the results drawn from this study as a disaster prevention tool to use in a safety education class, and not consider this simply as statistical data, but as a checklist to ensure full awareness of the appropriate priorities for safety categories to utilize in the reinforced concrete construction in order to execute reasonable safety management.

• Applied Science and Convergence Technology
• /
• v.26 no.4
• /
• pp.70-73
• /
• 2017

The dielectric constant and loss of poling/non-poling was measured in the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ samples. The addition of $La^{3+}$ to the $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ did not cause a large change in grain size. But the addition of $La^{3+}$ did show transition temperature, which shifted toward low temperature in the $Pb[(Mg_{1/3}Ta_{2/3})Zr]O_3$ systems. In addition, the dielectric and pyroelectric properties (${\varepsilon}{\sim}20000$, $p{\sim}0.03C/m^2K$) of this system using $La^{3+}$ have been greatly improved. Pyroelectrics $Pb_{0.97}La_{0.02}(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ system was found to have a relatively high ferroelectric FOMs ($F_V{\sim}0.035m^2/C$, $F_D{\sim}0.52{\times}10^{-4}Pa^{-1/2}$) at room temperature. Spontaneous polarization showed a value of $0.27{\sim}0.35C/m^2$ in the composition added to $La^{3+}$. The piezoelectric constant ($d_{33}=350{\sim}490pC/N$) and electromechanical coupling factor ($k_P=0.25{\sim}0.35$) are obtained in $Pb_{1-3x/2}La_x[(Mg_{1/3}Ta_{2/3})_{0.66}Zr_{0.34}]O_3$ compositions with $La^{3+}$ dopant.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.3
• /
• pp.11-20
• /
• 2016

In this paper, we propose the channel estimation scheme for Long Term Evolution-Advanced (LTE-A) downlink system. The proposed scheme uses the fast fourier transform (FFT) interpolation scheme for the user moving at a high speed. The FFT interpolation scheme converts the channel frequency response obtained from least square (LS) or minimum mean square error (MMSE) channel estimation scheme to time domain channel impulse response by taking the inverse FFT (IFFT). After windowing the channel response in the time domain, we can obtain the channel frequency response by taking the FFT. We perform the system level simulation based on 20MHz bandwidth of 3GPP LTE-A downlink system. Simulation results show that the proposed channel estimation scheme can improve signal-to-noise-plus-interference ratio (SINR), throughput, and spectral efficiency of conventional system.

• Journal of Convergence for Information Technology
• /
• v.9 no.10
• /
• pp.244-253
• /
• 2019

This study was a descriptive study to investigate the effects of healthcare workers' consciousness of biomedical ethics, recognition of good death, and self-esteem on attitude toward advance directive. Participants in this study were 292 healthcare workers in the three general hospitals located Y city. The data were collected from April 2 to April 23, 2019 and analyzed descriptive statistics, t-test, one-way ANOVA, Pearson correlation coefficient, and multiple regression using the SPSS Win. 22.0 program. The result of the multiple regression indicates the intention to awareness regarding advance directives, intention to execute advance directives, time to complete advance directives and recognition of good death predict 23.5% (F=12.39, P=.000) of attitudes toward advance directives. Therefore, it is necessary to develop a program to establish attitudes toward advance directives by providing education on recognition of good death of healthcare workers.

• Journal of Convergence for Information Technology
• /
• v.9 no.10
• /
• pp.163-169
• /
• 2019

The purpose of this study is to examine about PBL implementation strategies employed by faculty members who have successfully managed PBL class. By adopting the inductive content analysis, this study has analyzed the contents related with the strategies about PBL implementation in the course result reports and best practice presentation materials made by 6 professors selected as a PBL best practicer of B university from the 2017 to the 2018. After the analysis, it is revealed that PBL best practicers have used 13 strategies in domain of classroom culture, learning facilitation, and assessment. The following further studies and supports have been suggest: First, a study on PBL best practice faculty member's implementation strategies should be further expanded. Second, a comparative study on the PBL implementation strategies between PBL best practice faculty members and general faculty members should be launched. Third, an organizational system to share PBL best practice faculty member's implementation strategies should be supported.

• Journal of Convergence for Information Technology
• /
• v.9 no.12
• /
• pp.190-197
• /
• 2019

The purpose of this study was conducted as a basic data for the formation of a correct job value and to investigate the relationship between lifestyles and their job value in the dental hygiene students. A self-reported questionnaire was completed by 237 dental hygiene students in Seoul city from September 1 to 30, 2018. The data were analyzed by t-test, one way ANOVA, Pearson's correlation. regression analysis. There were lifestyles(3.27), job value(3.77) in subject. The faster birth order, the higher tended to have the internal job value(p<.05). The challenge·adventure, family-oriented lifestyles were were higher in female(p<.05). In order for college students' lifestyles to have a positive meaning on job values, it is necessary to apply job values education, career aptitude tests, and application of individual counseling programs.

• Journal of Convergence for Information Technology
• /
• v.8 no.3
• /
• pp.39-51
• /
• 2018

Objectives: The purpose of the study was to identify the factors influencing the nursing students' core competencies on disaster nursing. Methods: A sample of convenience was 224 nursing students, and a questionnaire was used to measure their disaster awareness, disaster preparedness, ego-resiliency, and core competencies on disaster. Results: A significant positive correlation was found among core competencies, disaster awareness, disaster preparedness, and ego-resiliency. Disaster preparedness(${\beta}=.413$), grade of which the participant was in(${\beta}=.165$), satisfaction on clinical practice(${\beta}=-.160$), ego-resiliency(${\beta}=.159$), and disaster related education experience(${\beta}=-.120$) were significant predictive variables of which accounted for 38.5% of the variance in core competencies. Conclusions: The results from this study can be used to develop programs for core competencies on disasters nursing.

• Journal of Convergence for Information Technology
• /
• v.11 no.9
• /
• pp.28-34
• /
• 2021

In the case of object detection using deep learning, both accuracy and real-time are required. However, it is difficult to use a deep learning model that processes a large amount of data in a limited resource environment. To solve this problem, this paper proposes an object detection model for small embedded devices. Unlike the general detection model, the model size was minimized by using a structure in which the pre-trained feature extractor was removed. The structure of the model was designed by repeatedly stacking lightweight convolution blocks. In addition, the number of region proposals is greatly reduced to reduce detection overhead. The proposed model was trained and evaluated using the public dataset PASCAL VOC. For quantitative evaluation of the model, detection performance was measured with average precision used in the detection field. And the detection speed was measured in a Raspberry Pi similar to an actual embedded device. Through the experiment, we achieved improved accuracy and faster reasoning speed compared to the existing detection method.

• Journal of Convergence for Information Technology
• /
• v.9 no.1
• /
• pp.99-104
• /
• 2019

In an attempt to shed light on the effects of overseas internships on foreign language development, this study investigated the differences in English compositions written by 10 Korean university students who joined an overseas internship program for 15 weeks. For data collection, the participants each wrote an English composition before and after the internship. Data collected was analyzed to discern differences in the two writings, and statistical analyses were carried out of the results. Results showed that the participants appeared to have attained lexical fluency, generating longer sentences embedded with multisyllabic, more diverse types, more complex and less redundant words in more complicated structures after the internship. This study revealed that overseas internships facilitated the growth of linguistic abilities. Korean SMEs need to enhance the global capacity of their human resources via overseas internships to strengthen their global competitiveness, apart from improving their industrial competencies such as productivity and product quality.