• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.549-552
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• 2018

One of railway communication technology, LTE(Long Term Evolution) based LTE-R(LTE-Railway) is rapidily adopted to supply various control signal and to supply diverse communication service be needed for safety operation of train. In this paper, railway communication technology and service based on LTE-R is studied. And domestic an international standardization trends of related on railway communications are investigated. Results of this study can be used as basic data for research of railway communication based on LTE-R and development of railway communication systems.

• The Journal of the Korea Contents Association
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• v.7 no.10
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• pp.69-79
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• 2007

Recently, elementary schools has assigned students information communication technology class for 1 hour in every week, all more than 34 hours a year during the discretion activity classes in every grades. However, the guidelines for information communication technology class is only suggested, but the teaching materials that can be used in the information communication technology class are not various. We did an analysis of a guide to information communication technique education that the Ministry of Education and Human Resources Development announced. And then, We developed the materials which can improve fifth and sixth grade children's creativity. We tried to find out how this materials affect their creativity.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1221-1224
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• 2004

This paper presents the programmable logic controller (PLC) networking development for communication with the mobile phone. The proposed technique is suitable for remote sensing control systems, which can display the operation status and monitoring fault diagnosis of a system. The system operation is based on the use of personal computer (PC) to logically analyze data from PLC, and existing internet protocol for sending information messages to mobile phones.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.739-748
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• 2014

In this paper, we propose pyramid appearance and global structure action descriptors on both RGB and depth motion history images and a model-free method for human action recognition. In proposed algorithm, we firstly construct motion history image for both RGB and depth channels, at the same time, depth information is employed to filter RGB information, after that, different action descriptors are extracted from depth and RGB MHIs to represent these actions, and then multimodality information collaborative representation and recognition model, in which multi-modality information are put into object function naturally, and information fusion and action recognition also be done together, is proposed to classify human actions. To demonstrate the superiority of the proposed method, we evaluate it on MSR Action3D and DHA datasets, the well-known dataset for human action recognition. Large scale experiment shows our descriptors are robust, stable and efficient, when comparing with the-state-of-the-art algorithms, the performances of our descriptors are better than that of them, further, the performance of combined descriptors is much better than just using sole descriptor. What is more, our proposed model outperforms the state-of-the-art methods on both MSR Action3D and DHA datasets.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.51-61
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• 2010

Nowadays, there are various networked systems with many computers. In most networked systems, a crucial objective is to keep transmitting and/or receiving data continuously even though failures exist. How can one make a computer continue transmitting and/or receiving data even when there are some errors on a link? Fault-Tolerant Ethernet (FTE) can be a solution to this question. In this paper, we propose a Localized Software-based Fault-Tolerant Ethernet (LSFTE). Our new approach fulfills the general FTE requirements. It takes advantage of redundant cable lines to maintain communication in a faulty environment. A software layer, which uses a simple and effective algorithm, is added above the LAN card driver software to detect and overcome faults. For our approach, there is no need to change the existing hardware or the end-use interfaces. Furthermore, the fault-detection time is reduced significantly compared to the conventional software-based approach.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.171-175
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• 2012

Recently, the research on ICT (Information and Communication Technology), which cognizes and communicates human's emotion through information technology, is increasing. For instance, there are researches on phones and services that perceive users' emotions through detecting people's voices, facial emotions, and biometric data. In short, emotions which were used to be predicted only by humans are, now, predicted by digital equipment instead. Among many ICT researches, research on emotion recognition from face is fully expected as the most effective and natural human interface. This paper studies about sensitivity ICT and examines mechanism of facial expression recognition system as an example of sensitivity ICT.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.1042-1058
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• 2024

Terahertz (THz) communication is becoming a key technology for future 6G wireless networks because of its ultra-wide band. However, the implementation of THz communication systems confronts formidable challenges, notably beam splitting effects and high computational complexity associated with them. Our primary objective is to design a hybrid precoder that minimizes the Euclidean distance from the fully digital precoder. The analog precoding part adopts the delay-phase alternating minimization (DP-AltMin) algorithm, which divides the analog precoder into phase shifters and time delayers. This effectively addresses the beam splitting effects within THz communication by incorporating time delays. The traditional digital precoding solution, however, needs matrix inversion in THz massive multiple-input multiple-output (MIMO) communication systems, resulting in significant computational complexity and complicating the design of the analog precoder. To address this issue, we exploit the characteristics of THz massive MIMO communication systems and construct the digital precoder as a product of scale factors and semi-unitary matrices. We utilize Schatten norm and Hölder's inequality to create semi-unitary matrices after initializing the scale factors depending on the power allocation. Finally, the analog precoder and digital precoder are alternately optimized to obtain the ultimate hybrid precoding scheme. Extensive numerical simulations have demonstrated that our proposed algorithm outperforms existing methods in mitigating the beam splitting issue, improving system performance, and exhibiting lower complexity. Furthermore, our approach exhibits a more favorable alignment with practical application requirements, underlying its practicality and efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4203-4223
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• 2021

Accelerated by the Internet of Things (IoT), the need for further technical innovations and developments within wireless communications beyond the fifth generation (B5G) networks is up-and-coming in the past few years. High altitude platform station (HAPS) communication is expected to achieve such high levels that, with high data transfer rates and low latency, millions of devices and applications can work seamlessly. The HAPS has emerged as an indispensable component of next-generations of wireless networks, which will therefore play an important role in promoting massive IoT interconnectivity with 6G. The performance of communication and key technology mainly depend on the characteristic of channel, thus we propose an efficient Markov chain based channel model, then analyze the HAPS communication system's uplink capability and swing effect through experiments. According to the simulation results, the efficacy of the proposed scheme is proven to meet the requirements of ubiquitous connectivity in future IoT enabled by 6G.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.415-420
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• 2007

Diffusion of information and communication technologies is a global phenomenon. In spite of rapid globalization there are considerable differences between nations in terms of the adoption and usage of new technologies. Several studies exploring causal factors including national cultures of information and communication technology adoption have been carried out. The focus of this paper is slightly different from other studies in this area. Rather than concentrating on the individual information technology the cyber diplomacy is the focus. This research conducted an analysis of the impact national culture has on adoption of the cyber diplomacy and its components for 95 countries. The national cultural dimensions were identified using Hofstede's model of cultural differences. The research model and hypotheses were formed and tested using correlation and regression analysis. The findings indicate that worldwide cyber diplomacy adoption is related to national culture. The result has theoretical and practical implications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2243-2257
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• 2019

A heterogeneous cellular network (HCN) is useful to increase the spectral and energy efficiency of wireless networks and to reduce the traffic load from the macro cell. The performance of the secondary user equipment (SUE) is affected by interference from the eNodeB (eNB) in a macro cell. To decrease the interference between the macro cell and the small cell, allocating resources properly is essential to an HCN. This study considers the scenario of a software-defined heterogeneous cellular network and performs the resource allocation process. First, we show the system model of HCN and formulate the optimization problem. The optimization problem is a complex process including power and frequency resource allocation, which imposes an extremely high complexity to the HCN. Therefore, a hierarchical resource allocation scheme is proposed, which including subchannel selection and a particle swarm optimization (PSO)-based power allocation algorithm. Simulation results show that the proposed hierarchical scheme is effective in improving the system capacity and energy efficiency.