• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.9-17
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• 2010

Recently, there has been much interest in orthogonal frequency division multiplexing (OFDM) for next generation wireless wideband communication systems. OFDM is a special case of multicarrier transmission, where a single data stream is transmitted over a number of lower-rate subcarriers. One of the main reasons to use OFDM is to increase robustness against frequency-selective fading or narrowband interference. However, in the radio systems it is also important to distortion introduced by high power amplifiers (HPA's) such as solid state power amplifier (SSPA) considered in this paper. Since the signal amplitude of the OFDM system is Rayleigh-distributed, the performance of the OFDM system is significantly degraded by the nonlinearity of the HPA in the OFDM transmitter. In this paper, we propose a canonical piecewise-linear (PWL) model based digital predistorter to prevent signal distortion and spectral re-growth due to the high peak-to-average power ratio (PAPR) of OFDM signal and the nonlinearity of HPA's. Computer simulation on an OFDM system under additive white Gaussian noise (AWGN) channels with QPSK, 16-QAM and 64-QAM modulation schemes and modulator/demodulator implemented with 1024-point FFT/IFFT, demonstrate that the proposed predistorter achieves significant performance improvement by effectively compensating for the nonlinearity introduced by the SSPA.

• Journal of Distribution Science
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• v.13 no.5
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• pp.91-102
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• 2015

Purpose - This study aims to build a systematic frame for effective marketing performances by prioritizing product type and pertinent channel that are appropriate for digital channel characteristics. FCB grid model was used to define a product type, and Internet communication satisfaction index was considered as a marketing performance measuring tool for digital channel. Research design, data, and methodology - As systematic understanding for Digital marketing is still unfamiliar to even professional marketer, the hypothesis was established based on preliminary research by conducting a qualitative survey of marketing experts who already experienced digital marketing in the fields as well as existing related study literature. Through a preliminary research, the degree for understanding for digital marketing, current digital marketing (including product/channel mix) execution status, and difficulties for marketers who had experienced digital marketing were figured out. Based on preliminary research, the main part of survey was designed to examine which type of product would be effective for digital marketing and which digital channel would be effective to achieve marketing performance in line with marketing objectives. To collect data, the questionnaire survey was conducted for professional marketers who had experienced digital marketing in 10 different fields including FMCG, cosmetics, distribution industry for one month (July, 10, 2014~Aug, 10, 2014). A total of 90 questionnaire were distributed and 66 questionnaires were used for the analysis, excluding the unanswered and insincere questionnaires. The data were analysed using SPSS ver.18.0. Results - The analysis for product type which is pertinent to digital marketing and prioritization for digital channel per digital marketing performance type could be summarized as followings. First, high involvement buying decision type of product and rational purchasing decision type of product in FCB grid are more effective for digital marketing in terms of marketing performance. Therefore, marketers in field would prioritize considering product type before executing digital marketing. Second, factor for sales increase, potential consumer creation and brand awareness was represented respectively 31.25%, 21.9%, and 20.8% as a result of factor analysis in terms of digital marketing channel performance. Third, effective major digital channel per digital marketing performance factor was differently identified as each digital channel has its own peculiarity. For instance, search engine is more effective for increasing sales while social media such as facebook and Kakaotalk is more effective for encouraging consumer participation. Conclusions - As a result of this study, product type and peculiarity which were pertinently fit to digital marketing were identified by using FCB grid model, and also suggested framework for decision making of digital channel selection in line with marketing objectives for effective marketing performance. It also provided insight to professional marketer which type of product could be effective for digital marketing execution as well as which factors should be measured for digital marketing performance.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.37-47
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• 2018

The number of capabilities of Internet of Things (IoT) devices will exponentially grow over the next years. These devices may generate a vast amount of time-constrained data. In the context of IoT, data management should act as a layer between the objects and devices generating the data and the applications accessing the data for analysis purposes and services. In addition, most of IoT services will be content-centric rather than host centric to increase the data availability and the efficiency of data delivery. IoT will enable all the communication devices to be interconnected and make the data generated by or associated with devices or objects globally accessible. Also, fog computing keeps data and computation close to end users at the edge of network, and thus provides a new breed of applications and services to end users with low latency, high bandwidth, and geographically distributed. In this paper, we propose Edge-Fog cloud-based Hierarchical Data Delivery ($EFcHD^2$) method that effectively and reliably delivers IoT data to associated with IoT applications with ensuring time sensitivity. The proposed $EFcHD^2$ method stands on basis of fully decentralized hybrid of Edge and Fog compute cloud model, Edge-Fog cloud, and uses information-centric networking and bloom filters. In addition, it stores the replica of IoT data or the pre-processed feature data by edge node in the appropriate locations of Edge-Fog cloud considering the characteristic of IoT data: locality, size, time sensitivity and popularity. Then, the performance of $EFcHD^2$ method is evaluated through an analytical model, and is compared to fog server-based and Content-Centric Networking (CCN)-based data delivery methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.10
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• pp.1277-1286
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• 2018

In this paper, we provide flexible scalability of computing resources in cloud environment and Apache Hadoop based cloud environment for analysis of public medical information big data. In fact, it includes the ability to quickly and flexibly extend storage, memory, and other resources in a situation where log data accumulates or grows over time. In addition, when real-time analysis of accumulated unstructured log data is required, the system adopts Hadoop-based analysis module to overcome the processing limit of existing analysis tools. Therefore, it provides a function to perform parallel distributed processing of a large amount of log data quickly and reliably. Perform frequency analysis and chi-square test for big data analysis. In addition, multivariate logistic regression analysis of significance level 0.05 and multivariate logistic regression analysis of meaningful variables (p<0.05) were performed. Multivariate logistic regression analysis was performed for each model 3.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.1
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• pp.17-28
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• 2019

In the financial investment management strategy, the distributed investment selecting and combining various financial assets is called portfolio management theory. In recent years, the blockchain based financial assets, such as cryptocurrencies, have been traded on several well-known exchanges, and an efficient portfolio management approach is required in order for investors to steadily raise their return on investment in cryptocurrencies. On the other hand, deep learning has shown remarkable results in various fields, and research on application of deep reinforcement learning algorithm to portfolio management has begun. In this paper, we propose an efficient financial portfolio investment management method based on Asynchronous Advantage Actor-Critic (A3C), which is a representative asynchronous reinforcement learning algorithm. In addition, since the conventional cross-entropy function can not be applied to portfolio management, we propose a proper method where the existing cross-entropy is modified to fit the portfolio investment method. Finally, we compare the proposed A3C model with the existing reinforcement learning based cryptography portfolio investment algorithm, and prove that the performance of the proposed A3C model is better than the existing one.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.153-162
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• 2022

Relevance. Innovative activities in education should be aimed at ensuring the comprehensive development of the individual and professional development of students. The main idea of modular technology is that the student should learn by himself, and the teacher manages his learning activities. The advantage of modular technology is the ability of the teacher to design the study of the material in the most interesting and accessible forms for this part of the study group and at the same time achieve the best learning results. Innovative Moodle technology. it is gaining popularity every day, significantly expanding the space of teaching and learning, allowing students to study inter-faculty university programs in depth. The purpose of this study is to assess the quality of implementation of the e-learning system Moodle. The study was conducted at the South Ukrainian National Pedagogical University named after K. D. Ushinsky in order to identify barriers to the effective implementation of innovative distance learning technologies Moodle and introduce a new model that will have a positive impact on the development of e-learning. Methodology. The paper used a combination of theoretical and empirical research methods. These include: scientific analysis of sources on this issue, which allowed us to formulate the initial provisions of the study; analysis of the results of students 'educational activities; pedagogical experiment; questionnaires; monitoring of students' activities in practical classes. Results. This article evaluates the implementation of the principles of distance learning in the process of teaching and learning at the University in terms of quality. The experiment involved 1,250 students studying at the South Ukrainian National Pedagogical University named after K. D. Ushinsky. The survey helped to identify the main barriers to the effective implementation of modern distance learning technologies in the educational process of the University: the lack of readiness of teachers and parents, the lack of necessary skills in applying computer systems of online learning, the inability to interact with the teaching staff and teachers, the lack of a sufficient number of academic consultants online. In addition, internal problems are investigated: limited resources, unevenly distributed marketing advantages, inappropriate administrative structure, and lack of innovative physical capabilities. The article allows us to solve these problems by gradually implementing a distance learning model that is suitable for any university, regardless of its specialization. The Moodle-based e-learning system proposed in this paper was designed to eliminate the identified barriers. Models for implementing distance learning in the learning process were built according to the CAPDM methodology, which helps universities and other educational service providers develop and manage world-class online distance learning programs. Prospects for further research focus on evaluating students' knowledge and abilities over the next six months after the introduction of the proposed Moodle-based program.

• The Journal of Korean Academic Society of Nursing Education
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• v.4 no.2
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• pp.220-235
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• 1998

The revolution of nursing curriculum has been focused on clinical competency for nursing graduates to flexibly respond to changes in societal health needs and disciplinary requirements. In this trend, the study was designed to identify basic concepts of nursing education that reflects the changes in societal needs and nursing discipline, and to develop the instrument to measure performance level in each dimension of clinical competency. The study was conducted in two phases. In phase 1, principal concepts consisted of nursing education were determined through literature review as well as series of discussion sessions on nursing philosophies and educational objectives among researchers. Though the process, the conceptual framework of competency based nursing curriculum was constructed with nursing process and professional role as horizontal threads, client, health needs, and nursing interventions as vertical threads. Then, items were developed to represent each dimension of competency : client and health need, nursing process, professional role, and nursing interventions. The total of 273 items were included as to represent clinical competency required for BSN graduates. In phase 2, questionnaires were distributed to nursing faculties of 41 BSN programs to validate the 273-item Instrument developed to measure competency. The total of 34 subjects returned the questionnaire with 81% of response rates. The subjects of the study had an average of 42 months of clinical experience and 13 years of education experience in various nursing areas with an age range of 30 to 52 years. The data were analyzed by utilizing SPSSWIN and the results are as follows. 1) The mean score of the nursing process dimension was supported most with the mean of 3.60(SD=0.32) compared to client and health need dimension(M=3.49, SD=.40), professional role(M=3.41, SD=.44), and nursing interventions(M=3.57, SD=.34). 2) The dimensions of competency were moderately correlated to each other with a range of r=.433 to r=.829, confirming that four dimensions of competency were related but distinct concepts. 3) The items of each dimension were analyzed based on its appropriateness. 'Assessing risk factors of the clients' were most highly supported in client and health need dimension. Most items of nursing process dimension were considered appropriate, while items related to efficient communication were well supported in professional role dimension. In nursing intervention dimension, items on basic nursing skills were highly supported while items on specific nursing interventions such as music therapy or art therapy were considered relatively inappropriate to competency for BSN graduates. The findings clearly showed that the current nursing education more emphasizes nursing interventions based on nursing process than other dimensions of competency. There is a need to reconceptualize nursing curriculum that is able to reflect more of nursing professional role and client/health need dimensions. Further research to validate the instrument by confirming competency dimensions of nursing graduates who are currently working at the hospital has been suggested.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.427-440
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• 2020

This study is a study on the cooking department where chefs who belong to the desired job of elementary and middle school students work together with the recognition increase through the media. The cooking department, which has a vertical structure at work, can be said to have an absolute influence of the chef. However, the cooking department needs to change according to the times. The purpose of this study was to examine how chef's shared leadership affects the chef's emotional commitment, continuous commitment, job satisfaction, and job performance. Therefore, a questionnaire was distributed to the employees currently working in the cooking department of a five-star hotel in Seoul, and a sample of 319 copies was prepared. In statistical analysis, the items were refined through exploratory factor analysis, confirmatory factor analysis, reliability analysis, and correlation analysis, and the hypotheses were verified through structural model analysis.As a result, Chef's shared leadership influences the emotional commitment of cooks, job satisfaction and job performance. In particular, emotional commitment and continuous commitment did not affect cooks' job satisfaction and job performance. In conclusion, to improve the performance of the organization, the hotel culinary department must establish a culture of sharing and communication. This suggests that establishing goals and visions will lead to job satisfaction and performance not only for individual cooks but also for the entire department. Therefore, it is expected to contribute to the efficient human resource management for the cooks in the hotel cooking department.

• The Korean Journal of Franchise Management
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• v.12 no.3
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• pp.7-19
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• 2021

Purpose: The hotel industry needs a leader who can actively demonstrate leadership to respond to and accept changes in the organization in a highly competitive and fast-changing environment. Therefore, the role of leaders who instill clear vision and goals of the organization in their members, listen to their opinions, and empathize is paramount. Leaders should encourage successful organizational activities based on active participation by employees and create the best environment for working with a sense of mission and responsibility. This study aims to identify the relationship between empathy leadership and job engagement as a result variable of team cohesion in the hotel culinary department and conduct empirical studies on the role of empathy leadership and job engagement. Research design, data, and methodology: The data were collected from employees who work in culinary department at a five-star franchise hotel located in the Seoul metropolitan area. Because it is difficult to conduct a survey through face-to-face contact with employees due to the COVID-19 pandemic, the online survey was conducted from February 1 to February 28, 2020. A total of 330 questionnaires through online were distributed and 268 employees completed the survey, yielding a response rate of 81%. Of the 268 returned responses, 27 responses were not usable due to missing information. Thus, a total of 241 responses were used for analysis. Results: The study results are as follows. First, it has been shown that the empathy leadership of culinary department in hotel companies has a significant positive impact on the job engagement. Second, it has been shown that job engagement has a significant positive effect on members' team cohesiveness. Third, empathy leadership of hotel companies' culinary department has a significant positive impact on members' team cohesiveness. Fourth, job engagement has a significant positive (+) mediating effect in the relationship between empathy leadership and team cohesiveness in culinary department. Conclusion: This study supports the theory that an emotional and empathic leader's behavior or ability can change the effectiveness or atmosphere of a rapidly changing hotel culinary team organization by presenting a research model on the effect of empathic leadership on job engagement and team cohesiveness. And hotel chefs should be more aware of the importance of empathic leadership and make them a human resource of the organization through formal and informal communication with culinary employees.

• The Korean Journal of Franchise Management
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• v.12 no.3
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• pp.35-46
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• 2021

Purpose: The hotel industry needs a leader who can actively demonstrate leadership to respond to and accept changes in the organization in a highly competitive and fast-changing environment. Therefore, the role of leaders who instill clear vision and goals of the organization in their members, listen to their opinions, and empathize is paramount. Leaders should encourage successful organizational activities based on active participation by employees and create the best environment for working with a sense of mission and responsibility. This study aims to identify the relationship between empathy leadership and job engagement as a result variable of team cohesion in the hotel culinary department and conduct empirical studies on the role of empathy leadership and job engagement. Research design, data, and methodology: The data were collected from employees who work in culinary department at a five-star franchise hotel located in the Seoul metropolitan area. Because it is difficult to conduct a survey through face-to-face contact with employees due to the COVID-19 pandemic, the online survey was conducted from February 1 to February 28, 2020. A total of 330 questionnaires through online were distributed and 268 employees completed the survey, yielding a response rate of 81%. Of the 268 returned responses, 27 responses were not usable due to missing information. Thus, a total of 241 responses were used for analysis. Results: The study results are as follows. First, it has been shown that the empathy leadership of culinary department in hotel companies has a significant positive impact on the job engagement. Second, it has been shown that job engagement has a significant positive effect on members' team cohesiveness. Third, empathy leadership of hotel companies' culinary department has a significant positive impact on members' team cohesiveness. Fourth, job engagement has a significant positive (+) mediating effect in the relationship between empathy leadership and team cohesiveness in culinary department. Conclusion: This study supports the theory that an emotional and empathic leader's behavior or ability can change the effectiveness or atmosphere of a rapidly changing hotel culinary team organization by presenting a research model on the effect of empathic leadership on job engagement and team cohesiveness. And hotel chefs should be more aware of the importance of empathic leadership and make them a human resource of the organization through formal and informal communication with culinary employees.