• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2813-2819
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• 2015

In this paper, we investigate the physical layer network coding (PNC) technique in a two-way relay channel (TWRC) where two source nodes send and receive data with each other via a relay node. In particular, we consider the communication scenario where packet length from the two sources is different from each other. We analyze the bit error rate (BER) of the received packet at the relay node according to degree of overlapping between two packets. The BER of the short packet remains unchanged regardless of the degree of overlapping since the entire packet is overlapped with the longer packet, while the BER of the longer packet becomes improved as the degree of overlapping decreases. Thus, we need a novel transmission scheme to enhance BER performance of the PNC technique in TWRC environments since the overall BER performance of the PNC technique at the relay node depends on the worse BER between two ovelapping packets' BERs.

• Journal of Agricultural Extension & Community Development
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• v.7 no.2
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• pp.359-376
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• 2000

The purposes of this exploratory study were to interrelate the scholastic discipline of the ‘development communication’ into ‘community development’ and ‘adult education’ in terms of interests, views and theoretical backgrounds of these fields of social sciences; and to draw some implications for developing scholastic interactions among these fields to pursue common social changes of human society. Development communications provide opportunities to set goals, to decide contents, and to utilize communication media in developmental efforts. Contemporary trends of development communication, community development and adult education are concerned with indigenous, two-way, bottom-up and people-centered communication from exogenous, one-way, top-down and institution-centered communication of the past. Multidisciplinary approaches to communication concepts and methodology may increase the potentials of community development and adult education in terms of efficiency and effectiveness. Some of the development communication approaches such as traditional and folk media approach. new media or ICT(information & communication technology) approach, participatory communication for development approach, communication support development approach and mass media approach may be applicable for community development and adult education. Better understanding on development communication approaches will be needed for the adult educators as well as community development practitioners.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.27-33
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• 2013

In this paper, we propose a pilot based channel estimation technique in two-way relay networks. We propose to transmit a pilot symbol together with the data symbol during transmission. In absence of Channel State Information (CSI), destination uses the pilot symbol to estimate the channel. In this system, the relay amplifies the pilot and the data symbol then forward them to the destination using amplify and forward (AF) protocol. We assume that the relay gain is fixed, so the relay does not need to estimate the channel, the destination only estimate the channel. We apply well-known Least-square (LS) and minimum mean-square error (MMSE) channel estimation methods to estimate the channel.

• Journal of information and communication convergence engineering
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• v.18 no.4
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• pp.254-259
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• 2020

Phased-array antennas comprise a demanding antenna design methodology for commercial wireless communication systems or military radar systems. In addition to these two important applications, the phased-array antennas can be used in beamforming for wireless charging. In this study, a four-way analog beamforming front-end module (FEM) for a hybrid beamforming system is developed for 2.4 GHz operation. In a hybrid beamforming scheme, an analog beamforming FEM in which the phase and amplitude of RF signal can be adjusted between the RF chain and phased-array antenna is required. With the beamforming and beam steering capability of the phased-array antennas, wireless RF power can be transmitted with high directivity to a designated receiver for wireless charging. The four-way analog beamforming FEM has a 32 dB gain dynamic range and a phase shifting range greater than 360°. The maximum output RF power of the four-way analog beamforming FEM is 40 dBm (=10 W) when combined the four individual RF paths are combined.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.201-206
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• 2011

With the development and supply of digital displayers, there has been a heightened interest of late in digital photo frames, eclipsing the existing print frames. This digital photo frame was developed into a new LCD digital photo frame that can be used not only for data display but also as a surveillance monitoring equipment when combined with a CCD camera. The developed photo frame uses a one-way communication encryption method that replaces the existing two-way communication encryption method to ensure the security of the surveillance image data. This method uses the chaotic signal's one-way synchronization phenomenon, where synchronization is made for a certain amount of time, after which the synchronized data can be encrypted and decoded at any point. It can yield the same results as the two-way communication encryption method. Moreover, if the proposed method is applied to the close-range communication methods of ubiquitous devices, it will be able to obtain more efficient results.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.4
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• pp.107-114
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• 2014

Things in the IoT(Internet of Things) make various services by exchanging information over networks. The IoT includes many types of WSNs(Wireless Sensor Networks) that consists of spatially distributed wireless sensor nodes and operates with the various purposes with useful technologies such as identification, sensing and communication. Typically, Zigbee network composed of low-cost and lowpower devices is mainly used for wide-area monitoring and remote device control systems. The IoT composed of various WSNs cannot interoperate among networks because of heterogeneous communication protocol and different data representation of each network, but can facilitate interconnection and information exchange among networks via the DDS, which is communication middleware standard that aims to enable real-time, high performance and interoperable data exchanges. In this paper, we proposed design of Zigbee Adaptor for two-way interoperation and data exchange between Zigbee network and other networks in the IoT. Zigbee Adaptor communicates with Zigbee network according to the Zigbee protocol and communicates with external networks via DDS. DDS-based Zigbee Adaptor can facilitate interoperation between a Zigbee network and external networks by systematic cooperation among its components.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.397-402
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• 2024

Speech recognition and motion recognition technologies are applied and used in various smart devices, but they are composed of simple command recognition forms and are used as simple functions. Apart from simple functions for recognition data, professional command execution capabilities are required based on data learned in various fields. Research is being conducted on a system platform that provides optimal data to users using Generative AI, which is currently competing around the world, and can interact through voice recognition and motion recognition. The main technical processes designed for this study were designed using technologies such as voice and motion recognition functions, application of AI technology, and two-way communication. In this paper, two-way communication between a device and a user can be achieved by various input methods through voice recognition and motion recognition technology applied with AI technology.

• Journal of Information Processing Systems
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• v.5 no.3
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• pp.135-144
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• 2009

Most of the tasks in wireless sensor networks (WSN) are requested to run in a real-time way. Neither EDF nor FIFO can ensure real-time scheduling in WSN. A real-time scheduling strategy (RTS) is proposed in this paper. All tasks are divided into two layers and endued diverse priorities. RTS utilizes a preemptive way to ensure hard real-time scheduling. The experimental results indicate that RTS has a good performance both in communication throughput and over-load.

• Korean Journal of Child Studies
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• v.29 no.6
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• pp.35-54
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• 2008

This study analyzed feelings of happiness in 550 5th grade children (273 males and 277 females) in elementary schools in Seoul and other regions. Measurement tools included personality (Eysenk, 1975), communication types (Barnes & Olsen, 1982), cognitive happiness (Waterman, 1993 and Ryff, 1989), affective happiness (Campbell et al. (1976), and eight open-ended questions about happiness developed by the author. Data analysis was by $X^2$, one-way ANOVA, stepwise regression analysis, and two-way ANOVA. Happiness of children was influenced by school grades, existence of supporters, economic level, number of siblings, and gender. Extroverted female children who had open communication with parents felt the highest degree of happiness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.545-563
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• 2015

Energy harvesting (EH) and network coding (NC) have emerged as two promising technologies for future wireless networks. In this paper, we combine them together in a single system and then present a time switching-based network coding relaying (TSNCR) protocol for the two-way relay system, where an energy constrained relay harvests energy from the transmitted radio frequency (RF) signals from two sources, and then helps the two-way relay information exchange between the two sources with the consumption of the harvested energy. To evaluate the system performance, we derive an explicit expression of the outage probability for the proposed TSNCR protocol. In order to explore the system performance limit, we formulate an optimization problem to minimize the system outage probability. Since the problem is non-convex and cannot be directly solved, we design a genetic algorithm (GA)-based optimization algorithm for it. Numerical results validate our theoretical analysis and show that in such an EH two-way relay system, if NC is applied, the system outage probability can be greatly decreased. Moreover, it is shown that the relay position greatly affects the system performance of TSNCR, where relatively worse outage performance is achieved when the relay is placed in the middle of the two sources. This is the first time to observe such a phenomena in EH two-way relay systems.