• 한국인터넷방송통신학회논문지
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• 제15권5호
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• pp.169-175
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• 2015

ICT 기술과 의료기술이 융합된 의료 정보기술에서 XML 기반의 CCR 문서는 환자 데이터의 연속성과 이동성을 확보해 준다. 대규모의 클라이언트들이 CCR 문서를 동시에 액세스할 때 클라이언트의 수에 상관없이 데이터 배표가 가능하게 해주는 확장성을 가진 무선 데이터 방송은 효율적인 정보 전달을 위한 하나의 대안이 된다. 본 논문은 무선데이터방송을 이용한 CCR 문서 전달을 위해 다양한 CCR 문서 스케줄링 기법과 인덱스 기법을 적용하여 최적의 클라이언트 성능을 낼 수 있도록 방송환경을 구축할 수 있는 무선 데이터 방송 시뮬레이션 프레임워크를 설계하고 구현한다. 구현된 프레임워크에 다양한 스케줄링 기법과 인덱스를 적용한 시뮬레이션을 통해 제안된 프레임워크의 효율성을 보였다.

• 한국정보통신학회논문지
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• 제24권11호
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• pp.1550-1553
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• 2020

In this paper, we maximize the lifetime of a multi-hop path through a cooperative wireless energy sharing scheme between constituent nodes in a wireless multi-hop communication. Considering a bidirectional multi-hop communication environment, we present an optimization problem to maximize path lifetime by adjusting the amount of energy each node needs to share with its neighboring nodes. On the basis of solidarity property, i.e., the lifetime of the multi-hop path is maximized when the lifetimes of all nodes are the same, we convert the considered optimization problem into a linear programming problem and solve it easily. Simulation result shows that the proposed two-way wireless energy sharing method maximizes the path lifetime of multi-hop communications and approximately doubles the path lifetime compared with the one-way energy sharing method.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.474-476
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• 2018

현재 기후 변화를 비롯한 여러 자연재해 및 여러 재해로 인해 막대한 손실을 가져오고 있으며, 이러한 자연재해는 원천적 차단은 어렵다. 그러나 이런 재난 현장의 정보를 실시간으로 수집하여 빠른 시간내에 피해를 줄이기 위한 방안으로 본 연구에서는 ICT 기술을 접목하여 대응전략을 구사하며, 미래 유비쿼터스 사회를 대비하기 위한 USN 기술을 응용한 모델이 필요하여 제안하고자 한다.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.88-93
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• 2020

The IEEE 802.11p-based wireless access in vehicular environments (WAVE) [1] communication is a method used exclusively for wireless communication on the road. This technique enables information sharing not only among moving vehicles but also between vehicles and infrastructure [2]. As part of WAVE communication, data is transmitted to and from vehicles in motion; in this case, it is difficult to determine the channel accurately in an outdoor environment owing to the Doppler shift [3]. This paper proposes a new channel estimation scheme for enhancing the reception performance of the IEEE 802.11p-based WAVE system. The proposed technique obtains the initial channel value by estimating the least square in the time domain by inserting a pilot signal for channel estimation into the IEEE 802.11p virtual subcarrier. Subsequently, a least mean square algorithm is applied to the initial channel value to update the estimated channel value. The simulation results obtained using the proposed channel estimation technique confirm its remarkable efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.280-294
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• 2023

Unmanned aerial vehicles (UAVs) and millimeter-wave frequencies play key roles in supporting 5G wireless communication systems. They expand the field of wireless communication by increasing the data capacities of communication systems and supporting high data rates. However, short wavelengths, owing to the high millimeter-wave frequencies can cause problems, such as signal attenuation and path loss. To address these limitations, research on high directional beamforming technologies continue to garner interest. Furthermore, owing to the mobility of the UAVs, it is essential to track the beam angle accurately to obtain full beamforming gain. This study presents a beam tracking method based on the unscented Kalman filter using hybrid beamforming. The simulation results reveal that the proposed beam tracking scheme improves the overall performance in terms of the mean-squared error and spectral efficiency. In addition, by expanding analog beamforming to hybrid beamforming, the proposed algorithm can be used even in multi-user and multi-stream environments to increase data capacity, thereby increasing utilization in new-radio multiple-input multiple-output orthogonal frequency-division multiplexing systems.

• 통상정보연구
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• 제16권4호
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• pp.55-75
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• 2014

본 연구는 국내 ICT 제조업과 서비스업의 경쟁력 강화를 위한 기초 연구로서 효율성과 생산성 추이 및 생산성의 결정요인을 분석하는 것을 목적으로 하였다. 구체적으로 본 연구는 ICT산업의 효율성 분석을 위해 ICT 제조업 23개 업종과 ICT 서비스업 18개 업종에 대하여 2007년부터 2011년까지 5년간 규모의 수익불변을 가정한 DEA(Data Envelopment Analysis)의 CCR모형과 규모의 수익가변을 가정한 BCC모형을 통해 기술효율성과 순수기술효율성의 정태적 효율성을 살펴보고, 기술효율성에 대한 DEA/Window 분석과 Malmquist 생산성 지수를 이용하여 동태적 효율성을 분석하였다.

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.138-145
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• 2010

In this paper, we report the test results of a small-scale prototype that implements an analogue-beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71~76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Measured performance is very close to the simulated results. An ad-hoc wireless communication system has also been demonstrated. Low BER was measured for an 8PSK data stream at 1.5 Gbps with the receive array beam formed in the direction of arrival of the transmitted signal. To our knowledge this is the first steerable antenna array reported to date in the E-band.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.218-226
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• 2019

The use of Information and Communication Technologies (ICT) is the key to operate a change from the traditional manual reading of water meters and sensors to an automated system where high frequency data is remotely collected and analyzed in real time, one of the main components of a Smart Water Grid. The recent boom of ICT offers a wide range of both wired and wireless technologies to achieve this objective. We review and present in this article the most widely recognized technologies and protocols along with their respective advantages, drawbacks and applicability range which can be Home Area Network (HAN), Building Area Network (BAN) or Local/Neighborhood Area Network (LAN/NAN). We also present our findings and we give recommendations on the application of ICT in Smart Water Grids and future work needed.

• ETRI Journal
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• 제45권6호
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• pp.939-951
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• 2023

It is critical to estimate the location using only Long-Term Evolution (LTE) and Wi-Fi information gathered by the user's smartphone and deployable for emergency rescue, regardless of whether the Global Positioning System is received. In this research, we used a vehicle to gather LTE and Wi-Fi wireless signals over a large area for an extended period of time. After that, we used the learning technique to create a positioning database that included both collection and noncollection points. We presented a two-step positioning algorithm that utilizes coarse localization to discover a rough location in a wide area rapidly and fine localization to estimate a particular location based on the coarse position. We confirmed our technology utilizing different sorts of devices in four regional types that are generally encountered: dense urban, urban, suburban, and rural. Results presented that our algorithm can satisfactorily achieve the target accuracy necessary in emergency rescue circumstances.

• International Journal of Human Ecology
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• 제16권2호
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• pp.79-88
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• 2015

As information and communications technology (ICT) becomes increasingly integrated into the daily lives of people around the world, it is important to know how the technology is influencing the behaviors of individuals and families. This study looked at the ecology of families as it is related to ICT and the changes to processes that occur as ICT devices and services are integrated into the family. A survey of 1084 families was conducted. Five hundred of the families were from the United States and 584 families were from Korea. Significant differences were found in the use of ICT by Korean and American families although the source of this difference was not clearly identified in this study. Three clusters of families were identified based on their use of devices and services. These were labeled as; 'The Tech Savvy', 'The Wireless Users', 'The In-betweeners', 'The Wired', and 'The Just Mobile'. 'The Tech Savvy' used the greatest variety of ICT technologies and 'The Wired' used the fewest. Other clusters fell in the middle with families seemingly using the devices which met their particular needs. Two factors related to ICT integration into the family were identified. These were related to family intimacy and family relationship maintenance. The family cluster identified as 'Tech Savvy' made significantly greater use of ICT in these relationships and 'The Wired' made the least use of ICT in these areas. The other clusters tended to be between the two ends and tended not to be significantly different from each other in their use of ICT. Finally, models for ICT use by families showed that demographics, nation of origin, types of devices and services used, and attitude and interest in ICT all had a significant impact.