• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.604-613
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• 2018

In this study, we analyzed the variations in the received signal strength index (RSSI) measured from Bluetooth beacons based on the strength and propagation direction of Bluetooth low energy (BLE) signal. Using a smartphone, we performed field experiments to investigate RSSI variations in the BLE signal transmitted by non-directional and directional beacons in an amethyst mine. In case of non-directional beacons, as the distance between the Bluetooth beacon and smartphone decreased, the RSSI increases, whereas as the BLE signal strength increased, the RSSI average gradually increased. The mean value of RSSI measured from the directional beacons was changed without relation to the facing angle between the Bluetooth beacon and smartphone. The results of this study can be used as basic data for developing a Bluetooth beacon-based proximity warning system for underground mines.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.49-57
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• 2021

This paper aims to confirm the effect of self-control and organization-control on information security attitude. The research method is composed of a cross-design of locus of control and tightness culture. The measurement variables used in the assessment are information security actual attitude, compliace behavioral attitude, and information security efficacy. As a result, the locus of control had a significant effect on information security actual attitude, information security efficacy, information security efficacy, and it was found that influence of the internal-based condition was greater than the external-based condition. The tightness culture had a significant effect on compliace behavioral attitude, information security efficacy, and it was found that influence of the tight culture-based condition was greater than the loose culture-based condition. In addition, the discussion contatins the implications of information security direction that reflect these research results.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.13-24
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• 2021

This was a one-group pretest-protest pre-experimental study designed to find out the effects of writing programs on college students using flipped learning for training convergence talents with complex problem solving skills. Data were collected from 27 C university students in G-do, from September 1st to October 30th, 2020. Analysis was done using IBM SPSS 25.0 for frequency (percentage), average, standard deviation, and paired t-test. The study showed that self leadership was enhanced by an average of 0.45 points (p<.001), metacognition by 0.87 points (p<.001), goal orientation by 0,77 points (p<.001), and creativity by 0.51 points (p<.001), so was statistically significant. The study demonstrated that writing programs using filpped learning had the effect of improving complex problem solving skills. so the results are expected to be used as basic data for the development of educational programs for traning convergence talents with problem solving skills at university-level. Also, for current college students that can freely access the online environment, development of various e-learning classes that apply flipped learning is needed.

• Journal of Practical Engineering Education
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• v.12 no.2
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• pp.275-291
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• 2020

This study aims to identify the structural relationship between mastery-approach goal orientation, instructor support, problem solving, collaborative skills, and course satisfaction among students who participated in project-based learning. To achieve the purpose of this research, researchers have conducted surveys between June and December in 2019. A total of 283 cases were selected for analysis. According to the study, mastery-approach goal orientation and instructor support have positive effects on problem solving and course satisfaction. Instructor support has positive effects on collaboration skills, and problem solving has positive effects on collaboration skills and course satisfaction. Also, the mediating effect of problem solving in the relationship among mastery-approach goal orientation, instructor support, collaboration skills, and course satisfaction was found to be statistically significant. However, the path between mastery-approach goal orientation and collaboration skills was not statistically significant. Based on these findings, academic and practical implications were suggested.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1261-1268
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• 2019

In this paper, we present the analysis of a novel monopole antenna with a reflector. The proposed monopole antenna is printed on a TRF-45 substrate, and the reflector, which is positioned near the base of the antenna, is printed on the FR-4 substrate. Positioning the reflector near the base of the antenna was found to suppress current radiation toward the back of the monopole antenna. Comparative analysis of the proposed monopole antenna and a conventional monopole antenna without a reflector revealed that the bandwidths of the antenna with and without a reflector were 2.65 GHz and 2.88 GHz, respectively. Additionally, the antenna without a reflector was observed to have a bi-directional radiation pattern in the E-plane, and an omni-directional radiation pattern in the H-plane. However, only the antenna with a reflector was found to suppress back radiation, and provide non-uniform directional radiation in the E-plane and H-plane.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.178-189
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• 2020

The purpose of this study was to analyze structural relationships with regard to the effect of customer integration, which is a type of integration in the supply chain, and market orientation of supply chain on the resulting change in the supply chain and management performance. The results of analysis in this study are as follows: First, customer integration and market orientation had a positive effect on reducing the flexibility and uncertainty of SCM. The decreased flexibility and uncertainty of SCM had a positive effect on non-financial performance, which also had a positive effect on financial performance. Second, customer integration and market orientation had a positive effect on financial and non-financial performance indirectly by decreasing the flexibility and uncertainty of SCM. Third, the effect of customer integration and uncertainty of SCM on the flexibility of SCM changed depending on the position in the supply chain; the effect was larger in the distribution group. The implications based on the analysis results are as follows: It is expected that the ability to deal with market changes in the overall supply chain is improved by laying the foundation for cooperation through establishing information infrastructure, including sharing information with trade partners and integrating systems, and implementing customer integration based on these achievements. It is also necessary to consider the business types and characteristics of individual companies in establishing information infrastructure.

• Journal of Korean Library and Information Science Society
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• v.52 no.1
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• pp.1-26
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• 2021

In most countries, public libraries have played a role as a hub of knowledge and information, complex culture of local communities, and a third place for meeting and communication. And recent public libraries are focusing on enhancing their core competencies and expanding services using digital technologies to meet the era of digital transformation and the 4th industrial revolution. However, after the COVID-19 pandemic occurred, all public libraries are repeatedly closed, reopened, and partially closed, and all resources are devoted to providing non-contact, digital and online alternative services, and are expected to continue in the future. As a result, future public libraries are bound to face a trilemma in which digital expandability, complex cultural space, and importance as a place of knowledge and information service are conflicting. This study discoursed on the public library trilemma in the post-COVID-19 era and suggested ways to overcome it. The orientation of the future public library is the fusion and harmony of multiplicity and multipurpose, place and space, knowledge & information and complex culture, face-to-face service and remote service. The main body of a public library is not the finger (digital and non-contact), but the moon (knowledge information center).

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.421-432
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• 2022

The purpose of this study was to analyze whether there are country differences in the intention to use Welfare Technology among older adults. Based on Technology Acceptance Model and Structural Equation Model, we surveyed total 334 older adults aged 65 and over living in Korea and the U.S. and analyzed the path differences between the perceived ease of use, perceived usefulness, attitude toward use, and intention to use of Welfare Technology between two countries. Results showed that the effect of 'perceived usefulness' on 'attitude toward use' was the highest in Korea at 0.74 (p<0.001), and 'Perceived ease of use' in 'Perceived Usefulness' in the United States at 0.75(p<0.001), with the differences being statistically significant. Findings indicate that 'Long-term Orientation' may explain the differences between the two countries. Practical and policy implications are presented in conclusion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.936-942
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• 2022

While indoor vehicle navigation is an essential component in large-scale parking garages of major cities, technical limitations and challenging propagation environments considerably degrade the accuracy of existing localization techniques. This paper proposes a proximity detection scheme using low-cost beacons where a handheld mobile device within a moving vehicle autonomously detects its approximate position and moving direction by only observing Received Signal Strength (RSS) values of beacon signals. The proposed approach essentially exploits the differential RSS technique of multi-directional beams to reduce the impact of the environment, vehicle, and mobile device. A low-cost multi-directional beacon prototype is developed using Bluetooth technology. The localization performance is evaluated using 96 beacons in an underground parking garage within an area of 394.8m×304.3m. Experimental results show that the 90th percentile of the average proximity detection error is 0.8m. Furthermore, our proposed scheme provides robust proximity detection performance with various vehicles and mobile devices.

• Journal of IKEEE
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• v.25 no.4
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• pp.591-597
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• 2021

This paper proposes an EMC-aware PCB design method to reduce electromagnetic emission, where trace length and teturn path of critical signal are shortened by changing chip location and trace layout on the PCB, while additional filters or decoupling capacitors are not required. In the proposed method, signal velocity is calculated for various signals on the PCB. Critical signal with the fastest signal velocity is determined and its return path is shortened as much as possible by placing chip location and trace routing first. Return path of critical signal should be carefully designed not to have discontinuity. Power plane and ground plane should be carefully designed not to be divided, since these planes are the reference of return path. The proposed method was applied to automotive directional Bluetooth speaker which failed to pass CISPR 32 and CISPR 25 EMC tests. Its PCB was redesigned based on the proposed method and it easily passed the EMC tests. The proposed method is useful to EMC-sensitive electronic equipments.