• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.78-82
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• 2022

Inorganic-organic hybrid perovskite solar cells have demonstrated considerable improvements, reaching 25.5% of certified power conversion efficiency (PCE) in 2020 from 3.8% in 2009 comparable to silicon photovoltacis. However, there remains important concern on the stability of perovskite solar cells under environmental conditions that should be solved prior to commercialization. In order to overcome the problem, we have introduced a small amount of octylammonium iodide with longer alkyl chain than volatile methylammonium iodide into MAPbI₃ perovskites. The presence of octylammonium into perovskites were confirmed using Fourier-transform infrared spectroscopy and UV-visible spectroscopy. Moreover, octylammonium-modified perovskite solar cells showed a PCE of 16.6% and enhanced moisture stability with an increased contact angle of 72.2° from 57.0°. This work demonstrated the importance of perovskite compositional engineering for improving efficiency and stability.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.179-188
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• 2022

The purpose of this study is to analyze the variables affecting the institutional commitment of college students. Based on the relevant literature review, this study subdivided institutional commitment of college students into three; academic integration, social integration and institutional commitment. To achieve the goals, the hierarchical regression analysis was conducted using KELS(Korea Educational Longitudinal Survey) data collected by KEDI in 2018. Major findings are as follows: factors related to college experiences such as learning styles, negligence of learning, college climate, interaction with faculty members or peer group were found to be associated with the institutional commitment of college students. With regard to students' background, male students revealed lower level of academic integration and institutional commitment. The regression model disclosed that students from medicine demonstrated higher social integration compared to other majors. Based on the findings of the study, policy implications were discussed.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.840-850
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• 2022

The purpose of this study is to translate The Digital Addiction Scale for Children(DASC) developed by Hawi, Samaha and Griffiths into Korean and to verify its validity. To translate and validate the original scale developed for 9-12 years old, 294 people aged 9-12 years who usually use digital devices, and exploratory factor analysis, confirmatory factor analysis, internal consistency, and validity analysis were conducted. In addition, reliability and validity analysis were conducted to confirm that this scale is a tool to measure the digital addiction of Korean children with high confidence level and validity. This study is meaningful in that it laid the foundations for related research by adapting and validating the digital addiction scale for children, which complements the limitations of the preceding measures, in accordance with the domestic situation in the situation where the digital addiction problem of children is getting serious.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.1-7
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• 2022

IoT technology that utilizes wireless body area networks (WBAN) and biosensors is an important field in the health industry to minimize resources and monitor patients. In order to integrate IoT and WBAN, a cooperative protocol that constitutes WBAN's limited sensor nodes and rapid routing for efficient data transmission is required. In this paper we propose an we propose an energy efficient and cooperative link energy-efficient routing strategy(LEERS) to solve the problems of redundant data transmission detection and limited network sensor lifetime extention. The proposed scheme considers the hop count node congestion level towards the residual energy sink and bandwidth and parameters. In addition, by determining the path cost function and providing effective multi-hop routing, it is shown that the existing method is improved in terms of residual energy and throughput

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.614-627
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• 2022

The purpose of this study was to explore the various data and methods employed by HR analytics studies. The researchers selected 78 KCI-indexed empirical articles on HR analytics and categorized them using the Employee Life Cycle framework. This yielded several important findings. First, employee retention has been the most common subject of extant studies, followed by performance management. Second, HR analytics studies have used a variety of data (structured and unstructured) according to their research questions, and the data sources have ranged from organizations' internal systems to national databases. Third, most domestic HR analytics studies have been descriptive and diagnostic, whereas predictive and prescriptive studies have been rare. These results have important theoretical and practical implications for future HR analytics research.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1312-1319
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• 2022

This paper defines an effectiveness index for optical continuous observation of unknown space objects and presents a range of design variables combinations that can satisfy the effectiveness index from a telescope/mount control system perspective using integrated simulation. The overall system-level simulation was implemented and the tracking performance was analyzed by considering design variables such as target position prediction and frame rate, image processing time and measurement error, target trajectory characteristics, and maneuver performance of mount gimbal. As a result of the analysis, it was confirmed that the continuous tracking performance of the optical observation system is dependent on the combination of frame rate and mount maneuver performance. In a situation where an optical observation system is designed or a similar system is implemented using COTS, an appropriate combination of parameters between design variables can be found through effectiveness analysis simulation as in this study.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.102-110
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• 2021

In this study, a related literature study was conducted to diagnose the status of overseas field practice and overseas employment programs, and a questionnaire was constructed and analyzed according to the CIPP model, and policy suggestions to promote effective overseas advancement programs in the future are presented. As a major result, it was investigated that in order to increase the satisfaction level of participants, it is necessary to have strong willingness to participate and to clearly set the goal of the overseas field practice and overseas employment program. In addition, it was analyzed that a system that can guarantee continuous support, such as local business trips and maintenance of relationships with companies, should be established even after successful overseas field practice and overseas employment. This study presents implications that may be helpful in establishing overseas field practice and overseas employment program policies of the national government, university, and local governments by confirming the positive effects and problems of current overseas field practice and overseas employment programs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1205-1214
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• 2021

Edge Computing is used as a solution to the cost problem and transmission delay problem caused by network bandwidth consumption that occurs when IoT/CPS devices are integrated into the cloud by performing artificial intelligence (AI) in an environment close to the data source. Since edge computing runs on devices that provide high-performance computation and network connectivity located in the real world, it is necessary to consider application integrity so that it is not exploited by cyber terrorism that can cause human and material damage. In this paper, we propose a technique to protect the integrity of edge computing applications implemented in a script language that is vulnerable to tampering, such as Python, which is used for implementing artificial intelligence, as container images and then digitally signed. The proposed method is based on the integrity protection technology (Docker Contents Trust) provided by the open source container technology. The Docker Client was modified and used to utilize the whitelist for container signature information so that only containers allowed on edge computing devices can be operated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.213-225
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• 2022

Containerization, a lightweight virtualization technology, enables agile deployments of enterprise-scale microservices in modern cloud environments. However, containerization also opens a new window for adversaries who aim to disrupt the cloud environments. Since microservices are composed of multiple containers connected through a virtual network, a single compromised container can carry out network-level attacks to hijack its neighboring containers. While existing solutions protect containers against such attacks by using network access controls, they still have severe limitations in terms of performance. More specifically, they significantly degrade network performance when processing packet payloads for L7 access controls (e.g., HTTP). To address this problem, we present BPFast, an eBPF/XDP-based payload inspection system for containers. BPFast inspects headers and payloads of packets at a kernel-level without any user-level components. We evaluate a prototype of BPFast on a Kubernetes environment. Our results show that BPFast outperforms state-of-the-art solutions by up to 7x in network latency and throughput.

• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.914-922
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• 2022

In this paper, we construct a commercial 4K UHD(Ultra High Definition) streaming device that utilizes a 5G mobile communication network as a transport channel and conduct a streaming performance test. It uses RTP(Realtime Transport Protocol) which has transmission quality monitoring capability as a transmission protocol to apply adaptive streaming. In addition, it provides the function to adjust the encoding rate of the video signal so that encoding can be optimized for the change in the bandwidth of the transmission channel. Through the performance test, it is confirmed that the H.265 encoding rate for 4K UHD signal is 48.69Mbps, the average glass-to-glass delay time is 293.60ms, and the average time difference between video and audio for lip sync is 120ms. With the result of performance test, it is shown that the streaming device is applied to 4K UHD Streaming device over 5G mobile communication network.