• Journal of the Korean Home Economics Association
• /
• v.41 no.1
• /
• pp.77-91
• /
• 2003

The purpose of this study was to explore the effects of children's perception of communications with mothers and self-control on game addiction. The subjects were 739 children of 4th, 5th and 6th grade. The subjects rated themselves on questionnaires regarding communications with mothers, self-control and game addiction scale. The major findings of this study were as follows: 1) 6th grade children addicted more than 4th and 5th grade children. And boys addicted more than girls. 2) Sex had a direct and indirect effect through children's perception of problematic communications with mothers and self-control on game addiction and was the first contribution factor Children's self-control had a first direct negative effect on game addiction. 3) Children's perception of problematic communications with mothers had a direct positive effect and an indirect positive effect through self-control on game addiction. Grade had a direct positive effect and an indirect positive effect through children's perception of open and problematic communications with mothers and self-control on game addiction. Children's perception of open communications with mothers had a direct positive effect and an indirect negative effect through self-control on game addiction.

• ETRI Journal
• /
• v.35 no.1
• /
• pp.120-130
• /
• 2013

This paper presents an analysis of resource assignment for multihop communications in millimeter-wave (mm-wave) wireless personal area networks. The purpose of this paper is to figure out the effect of using directional antennas and relaying devices (DEVs) in communications. The analysis is performed based on a grouping algorithm, categorization of the flows, and the relaying DEV selection policy. Three schemes are compared: direct and relaying concurrent transmission (DRCT), direct concurrent transmission (DCT), and direct nonconcurrent transmission (DNCT). Numerical results show that DRCT is better than DCT and DCT is better than DNCT for any antenna beamwidths under the proposed algorithm and policy. The results also show that using relaying DEVs increases the throughput up to 30% and that there is an optimal beamwidth that maximizes spatial reuse and depends on parameters such as the number of flows in the networks. This analysis can provide guidelines for improving the performance of mm-wave band communications with relaying DEVs.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.2
• /
• pp.20-26
• /
• 2013

We propose PHY Frame Structure for M2M direct communications in licensed frequency band. Especially, the proposed PHY Frame Structure coexists in the same licensed frequency band as currently operating cellular systems. Recently, Machine to Machine (M2M) service markets, including SmartGrid, Mobile Health, and Smart Car, are being rapidly expanded. Supporting M2M services in a specific case can waste Radio Resource in cellular systems. For example, when two M2M terminals communicating to each other are closely located, direct communication is radio resource efficient. In this paper, we set the requirement of maintaining the existing PHY frame structure in cellular systems to meet the backward compatibility. Based on this backward compatibility requirement, PHY frame structure for M2M direct communications is developed while satisfying coexistence with current operating cellular system. The proposed PHY frame structure meets backward compatibility. Accordingly, it is expected that the proposed M2M frame structure is useful for its frequency resource efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.2
• /
• pp.191-200
• /
• 2013

In this paper, we propose a new estimation method of time offset, frequency offset, and signal to interference plus noise ratio (SINR) using the synchronization channel preamble to provide IEEE 802.16.1a based talk-around direct communications (TDC). The proposed scheme estimates the time offset and frequency offset both in the time domain and in the frequency domain considering the preamble structure. In addition, it improves the estimation accuracy by combining the estimated values in two domains taking into account TDC synchronization scenarios. Through numerical simulations in the TDC channel environments, the performance of the proposed algorithm is compared with those of existing techniques such as the time domain estimation and the frequency domain estimation.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.784-787
• /
• 1999

This paper describes a direct digital frequency synthesizer using the CORDIC algorithm, which can be implemented efficiently for a digital sinusoid synthesis. To optimize the hardware design parameters, we perform numerical analysis of the quantization effects for the CORDIC-based architecture. A pipelined architecture is employed to obtain a high data throughput,. We estimate and summarize its hardware costs for a variable accuracy, and a CORDIC-based architecture for 9 bit accuracy is emulated in FPGA.

• Communications of the Korean Mathematical Society
• /
• v.10 no.4
• /
• pp.811-813
• /
• 1995

The purpose of this paper is to prove the divisibility of a direct injective module and every closed submodule of a $\pi$-injective module M is a direct summand of M.

• Communications of the Korean Mathematical Society
• /
• v.12 no.4
• /
• pp.865-868
• /
• 1997

Let R be a ring with a unity and let M be a unitary left R-module. In this paper, we establish [5, Proposition 2.8] by showing the proof of it. Moreover, from the above result, we obtain some properties of direct projective modules which have the summand sum property.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.193-194
• /
• 2007

In this paper we present work done by Kodak Graphic-Communications-Group and our partners demonstrating applications where laser direct imaging could replace photolithography in display manufacturing. Such applications range from direct manufacturing (e.g. LCD color-filters) to producing “masters” where manufacturing is done by traditional printing methods (e.g. flexography, Gravure-printing).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.10
• /
• pp.1194-1199
• /
• 2010

In this paper, for a relay-based cellular network, a interference avoidance beamforming technique is proposed to enhance direct link capacity while minimizing loss in the capacity of concurrent relaying link. A direct link is transmitted by beamforming at the transmitter, and the relaying link with the least interference to the direct link is scheduled to transmit data by a collision avoidance scheduling algorithm. Simulation results show that the proposed IA beamforming provides a considerable direct link capacity enhancement while minimizing relaying link capacity loss by effectively mitigating inference between concurrent direct and relaying links only with limited feedback.

• Information and Communications Magazine
• /
• v.30 no.6
• /
• pp.26-32
• /
• 2013

Wi-Fi Direct는 Wi-Fi Alliance에서 인증한 Wi-Fi 기반기술로 AP (Access Point)나 라우터 같은 인프라장비 없이 단말 간에 직접 통신을 하는 프로토콜 방식을 의미한다. Wi-Fi Direct는 현재 스마트폰 뿐만 아니라 TV, 노트북, 프린터, 카메라와 같은 다양한 기기 등에 탑재되어 단말 간 직접 통신을 통하여 콘텐츠 및 서비스를 사용할 수 있는 기술이다. 본고에서 Wi-Fi Direct 기술을 동작 단계별로 구체적으로 살펴보고 새롭게 정의된 전력 절감 기술에 대해서도 살펴본다. 또한 Wi-Fi Direct 기반 응용 서비스를 알아본다.