• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4050-4067
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• 2014

In wireless sensor networks, link scheduling is a fundamental problem related to throughput capacity and delay. For a given set of communication requests $L=\{l_1,l_2,{\cdots},l_n\}$, the MLS (maximum link scheduling) problem aims to find the largest possible subset S of Lsuch that the links in S can be scheduled simultaneously. Most of the existing results did not consider bidirectional transmission setting, which is more realistic in wireless sensor networks. In this paper, under physical interference model SINR (signal-to-noise-plus-interference-ratio) and bidirectional transmission model, we propose a constant factor approximation algorithm MLSA (Maximum Link Scheduling Algorithm) for MLS. It is proved that in the same topology setting the capacity under unidirectional transmission model is lager than that under bidirectional transmission model. However, compared with some work under unidirectional transmission model, the capacity of MLSA is improved about 28% to 45%.

• 인터넷정보학회논문지
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• 제18권6호
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• pp.15-23
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• 2017

Wireless power transmission (WPT) for wireless charging is currently attracting much attention as a promising approach to miniaturize batteries and increase the maximum total range of an electric vehicle. The main advantage of the laser power beam (LPB) approach is its high power transmission efficiency (PTE) over long distance. In this paper, we present the design of a laser power beam based WPT system, which has a best WPT channel selection technique at the receiver end when multiple power transmitters and single power receiver are operated simultaneously. The transmitters send their transmission channel information via optically modulated laser pulses. The receiver uses the received signal strength indicator and digitized data to choose an optimum power transmission path. We modeled a vertical multi-junction photovoltaic cell array, and conducted an experiment and simulation to test the feasibility of this system. From the experimental result, the standard deviation between the mathematical model and the measured values of normalized energy distribution is 0.0052. The error between the mathematical model and measured values are acceptable, thus the validity of the model is verified.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1841-1848
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• 2010

Electric railway system consist of rolling stock, track, signal and streetcar line system. ATP(Automatic Train Protection) system in railway signaling system is the important one grasping the position and velocity of a train. The wayside transmitter of ATP system is installed between rails. Recently, the research about increasing train speed has been developed in total departments of the railroad systems. The study on the information transmission between on-board transmitter and wayside transmitter is required for increasing the train speed in the ATP system. When the train speed is increased as to same transmissi on distance, the problem on information transmission occurs because the transmission time is decreased. In case that the transmission distance is extended, the transmission time is decreased with respect to the train speed. Therefore, we have to define the standard magnetic intensity as to the train speed in order to transmit correctly telegram. In this paper, the transmission distance for the telegram is suggested on the basis of the train speed. Also, the standard magnetic intensity from the wayside transmitter to on-board transmitter is proposed by using transmission distance regarding the train speed in the ERTMS/ETCS system by using Matlab program.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.467-468
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• 2008

In this paper, a logic family, the transmission gate CMOS(TG CMOS) is proposed, which combines the transmission gate and pass transistor resulting in a different configuration from traditional full CMOS. In the simulation, basic cells comprising this logic are designed and their dynamic responses are analyzed. The simulation shows their performance is exceeding that of conventional full CMOS.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1863-1866
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• 2002

This paper describes synthesis of a complex R$^{i}$ CR filter with a finite transmission zero except zero frequency. First, a new kernel function is proposed. Secondly, how to determine the element values included in the R$^{i}$ CR filter is described. A fifth-order R$^{i}$ CR filter is designed. Finally, the sensitivity property of the proposed filter is evaluated through computer simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권7호
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• pp.2513-2530
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• 2021

With the fast development of information and communication technologies, video streaming services and applications are increasing rapidly. However, the network condition is volatile. In order to provide users with better quality of service, it is necessary to develop an accurate and low-complexity model for Quality of Experience (QoE) prediction of time-varying video. Memory effects refer to the psychological influence factor of historical experience, which can be taken into account to improve the accuracy of QoE evaluation. In this paper, we design subjective experiments to explore the impact of Short-Term Memory (STM) on QoE. The experimental results show that the user's real-time QoE is influenced by the duration of previous viewing experience and the expectations generated by STM. Furthermore, we propose analytical models to determine the relationship between intrinsic video quality, expectation and real-time QoE. The proposed models have better performance for real-time QoE prediction when the video is transmitted in a fluctuate network. The models are capable of providing more accurate guidance for improving the quality of video streaming services.

• 한국정보통신학회논문지
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• 제18권9호
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• pp.2117-2123
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• 2014

현재 셀룰러 이동통신 시스템이 직면한 가장 큰 문제인 데이터 트래픽 폭증 수용문제를 효율적으로 해결하기 위한 방안으로써 스몰셀 및 단말간 통신 등 다양한 기술 등이 제안되고 있다. 이러한 데이터 트래픽 폭증 문제를 해결하기 위한 방안중 하나로써 기지국의 전송 파워를 서비스 받는 단말로 집중시키는 방향성 전송이 고려되고 있다. 본 연구에서는 셀룰러 이동통신 시스템에서 방향성 전송을 고려한 시스템 레벨 시뮬레이터를 개발하였고 방향성 전송이 사용될 때의 어려움 중 하나인 간섭 예측을 해결하기 위한 새로운 간섭 예측방안을 제안하였다. 본 시뮬레이터를 이용하여 제안된 적응적 간섭 예측 방안의 성능을 확인하였고 방향성 전송이 셀룰러 이동통신 시스템에서 활용될 때의 성능을 살펴보았다. 이를 통해 방향성 전송이 셀룰러 이동통신 시스템의 수율을 130% 이상 향상시킬 수 있음을 보였다.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.291-298
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• 2013

A science museum responds independently based on the exhibits and exhibition environments as the visitors are different in purposes, interests and demands. Therefore a science museum should be designed keeping it in mind that there are various ways for visitors to perceive and use the exhibition spaces and exhibits. The purpose of this study is to compare and analyze the characteristics of sensory receptors for the exhibits in National Museum of Nature and Science's Global Gallery, Tokyo, in terms of information transmission and to identify the nature of exhibit medium that can affect the perception and recognition of the exhibits by visitors. Through these 9 sensory receptors, human recognizes first with visual, auditory and olfactory senses and reacts using vestibular organ, proprioceptor (stretch), tangoreceptor, themoreceptor, taste and olfactory senses. Human uses these information processing to recolonize the external environment. This process is similar to the visitor's information transmission process for the exhibition medium. By dividing the analysis results per exhibition theme and developing the information transmission processing types per sensory receptor, we could understand that the distribution conditions are closely connected with the composition of the exhibition scenario in the exhibtion area. Especially, the understanding of how the information transmission is made through sensory receptors could can be the criteria that determines on the factors that can identify the exhibition purposes of a science museum which are eduction and understanding.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.79.6-79
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• 2002

We propose here sequential 2 methods for obtain information of current or potential data for power transmission line. One is a digital data transmission unit, this is, an output of a current sensor of power transmission line is digitalized by use of an easy asynchronous protocol. The unit has high speed transform rate, easy making header caused of consisting of only logic circuit. The other is, the output of the unit is transformed via LAN interface and displayed on a personal computer. We have confirmed remote measuring using the method for 100A and 240 A of the current information of power transmission line. Therefore we will be able to see a current waveform by use of internet at a cheep c...

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.925-928
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• 2013

본 논문에서는 기존 유선 전력 전송 기반 에너지 하베스팅 시스템에서 발생되는 문제점을 해결하기 위해 릴레이 기반의 무선 전력 전송 방식을 제안한다. 본 논문에서 제안하는 방식은 에너지 블록 내에 4방향코일을 배치하여 전자기 유도 기반의 무선 전력 전송을 수행할 수 있으며, 전송 신뢰성을 확보하기 위한 릴레이 제어 알고리즘을 통해 송 수신 경로를 확장할 수 있다.