• IEIE Transactions on Smart Processing and Computing
• /
• 제1권1호
• /
• pp.34-49
• /
• 2012

Recently, the smart grid (SG) has been introduced to solve the serious network issues caused by the increasing electrical demand and the complex nonlinear nature of the electric power distribution network. The SG, regarded as the next generation power grid, can transmit power in more efficient ways by building an automatic and distributed energy delivery network. In this paper, we first assess how various existing networking technologies, such as IEEE 802.11 (WiFi) and IEEE 802.15.4 (ZigBee), meet the requirements of the SG communication protocols. Specifically, we classify the existing network protocols into three categories: WSN-based networking, WiFi-based networking, and wireline-based networking. We then survey the security issues regarding the SG. Finally, we propose an agile SG networking architecture and show the effectiveness of different adopted networking technologies and, as a result, present a candidate solution to implement agile networking in SGs.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
• /
• pp.103-106
• /
• 2003

In this paper, we present a hybrid inertial and vision-based tracking system for VR applications. One of the most important aspects of VR (Virtual Reality) is providing a correspondence between the physical and virtual world. As a result, accurate and real-time tracking of an object's position and orientation is a prerequisite for many applications in the Virtual Environments. Pure vision-based tracking has low jitter and high accuracy but cannot guarantee real-time pose recovery under all circumstances. Pure inertial tracking has high update rates and full 6DOF recovery but lacks long-term stability due to sensor noise. In order to overcome the individual drawbacks and to build better tracking system, we introduce the fusion of vision-based and inertial tracking. Sensor fusion makes the proposal tracking system robust, fast, accurate, and low jitter and noise. Hybrid tracking is implemented with Kalman Filter that operates in a predictor-corrector manner. Combining bluetooth serial communication module gives the system a full mobility and makes the system affordable, lightweight energy-efficient. and practical. Full 6DOF recovery and the full mobility of proposal system enable the user to interact with mobile device like PDA and provide the user with natural interface.

• Rapid Communication in Photoscience
• /
• 제1권1호
• /
• pp.13-15
• /
• 2012

New porous $TiO_2$ nanostructures with shapes of pearl and rice were synthesized by hydrothermal treatment of $TiO_2$-liposome nanocomposites in acid and base solutions, respectively, as identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM) images and large Brunauer-Emmett-Teller (BET) surface areas. The x-ray diffraction (XRD) patterns and selected area electron diffraction proved them to be well-defined anatase crystals. Their UV-visible reflectance absorption spectra were observed to have low band gap energy (3.03 and 3.07 eV, respectively), exhibiting surface absorption band in the visible range from 400 to 600 nm. The degradation of methylene blue (MB) over the $TiO_2$ nanostructures was observed upon visible-light irradiation, which was found to be very efficient as compared with any other conventional visible-light responsive $TiO_2$ nanostructures.

• 디지털융복합연구
• /
• 제11권4호
• /
• pp.279-284
• /
• 2013

지구환경 개선을 위한 저탄소 배출 및 그린에너지에 관심이 높아지고 있으며, 이를 이루기 위한 기존의 전력망에 IT기술을 결합하여 보다 효율적이고 친환경적인 지능형 전력망을 이루는 스마트 그리드 사업이 전 세계적으로 활발히 전개되고 있다. 스마트 그리드는 양방향 디지털 기술을 사용하여 공급 업체와 소비자 사이에 전기를 제공하며, 소비자 집에 있는 지능형 가전이나, 에너지 절약 비용을 절감하고 안정성, 효율성 및 투명성을 높이기 위해 필요하며, 앞으로 지속적으로 발전될 것을 예상한다. 하지만, 스마트 그리드를 구축하기 위해서 반드시 선행되어야 하는 사항인 보안 모델을 구축하여 지능형 전력망을 안전하고 효율적으로 사용되도록 구축하는 방안을 제시하는 연구이다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권10호
• /
• pp.4618-4639
• /
• 2018

One of the most innovative paradigms for the next-generation of wireless cellular networks is the cloud-radio access networks (C-RANs). In C-RANs, base station functions are distributed between the remote radio heads (RHHs) and base band unit (BBU) pool, and a communication link is defined between them which is referred as the fronthaul. This leveraging link is expected to reduce the CAPEX (capital expenditure) and OPEX (operating expense) of envisioned cellular architectures as well as improves the spectral and energy efficiencies, provides the high scalability, and efficient mobility management capabilities. The fronthaul link carries the baseband signals between the RRHs and BBU pool using the digital radio over fiber (RoF) based common public radio interface (CPRI). CPRI based optical links imposed stringent synchronization, latency and throughput requirements on the fronthaul. As a result, fronthaul becomes a hinder in commercial deployments of C-RANs and is seen as one of a major bottleneck for backbone networks. The optimization of fronthaul is still a challenging issue and requires further exploration at industrial and academic levels. This paper comprehensively summarized the current challenges and requirements of fronthaul networks, and discusses the recently proposed system architectures, virtualization techniques, key transport technologies and compression schemes to carry the time-sensitive traffic in fronthaul networks.

• 한국컴퓨터정보학회논문지
• /
• 제16권2호
• /
• pp.217-224
• /
• 2011

기존의 유선상의 물리적 보안 시스템은 시간적, 공간적 제약을 갖는다. 이러한 문제점을 해결하기 위해서 본 연구는 스마트폰을 이용한 원격 물리적 보안 시스템을 구현 하였으며, 연구는 모바일 클라우드 컴퓨팅 기술을 기반으로 구현되었다. 모바일 클라우드 컴퓨팅 기술에서 요구되는 사용자 인증, 통신의 비밀성, 정보의 무결성, 시스템의 가용성, 접근제어 및 권한관리 그리고 안전한 핸드오프 등의 보안 기술을 구현하였다. 구현된 시스템은 계측, 감시, 제어를 통한 에너지 비용 절감 (5~30%)의 효율성을 갖는다. 본 시스템의 평균 접속 및 응답 시간 측정결과 값도 약 7.082초 이내로서 성능 대비 효율성이 높은 것으로 평가된다.

• Plant Biotechnology Reports
• /
• 제5권1호
• /
• pp.35-43
• /
• 2011

This communication describes for the first time an efficient and reproducible protocol for large-scale multiplication of Bambusa nutans. Nodal segments collected from field-grown clumps and cultured on Murashige and Skoog (MS) medium supplemented with $4.4{\mu}M$ benzylaminopurine (BA) and $2.32{\mu}M$ kinetin (Kin) gelled with 0.2% gelrite yielded 80% aseptic cultures with 100% bud-break. The in vitro-formed shoots obtained after bud-break were successfully multiplied in MS liquid medium supplemented with $13.2{\mu}M$ BA, $2.32{\mu}M$ Kin, and $0.98{\mu}M$ indole-3-butyric acid (IBA). Sub-culturing of shoots every 3 weeks on fresh multiplication medium yielded a consistent proliferation rate of 3.5-fold. Shoot clusters containing three to five shoots were successfully rooted with 100% success on half-strength MS liquid medium supplemented with $9.8{\mu}M$ IBA, $2.85{\mu}M$ indole-3-acetic acid (IAA), $2.68{\mu}M$ naphthaleneacetic acid (NAA), and 3% sucrose. Plantlets grown in vitro were acclimatized and subsequently transferred to the field. Inter-simple sequence repeat analysis has confirmed the genetic uniformity of the tissue-cultured plants up to 27 passages.

• 천문학회보
• /
• 제42권1호
• /
• pp.34.3-35
• /
• 2017

Spectral energy distribution camera for QUasars in EArly uNiverse (SQUEAN) is a successor of Camera for Quasars in EArly uNiverse (CQUEAN) which was developed by Center for the Exploration of the Origin of the Universe and operated at the 2.1 m Otto Struve Telescope in the McDonald Observatory, USA, since 2010. The software of SQUEAN controls a science camera, a guiding camera, and a filter wheel, and communicates with the telescope control system (TCS). It has been constantly revised and modularized according to the upgrades of the TCS and the hardware changes. Recently we have implemented the stable network communication and the semi-automatic focusing modules to enhance observational convenience. In this presentation we describe the current status of the SQUEAN control software and introduce a software architecture which is optimized on efficient astronomical observations.

• 전자공학회논문지CI
• /
• 제45권6호
• /
• pp.45-51
• /
• 2008

유시티를 비롯하여 여러 시범사업에서 나타나듯이 유비쿼터스 네트워크상에서 제공되는 서비스가 다양해질수록 안정적인 데이터 전송은 필수적인 요건이 되었다. 이렇듯 신뢰성은 서비스에서 요구하는 그 외의 서비스 품질상의 요구사항들에 앞서서 해결되어야 하는 가장 기본적인 사항이 되었다. 또한 유비쿼터스 센서 네트워크에서 가장 중요시 생각하는 저전력 통신의 근간을 지키기 위해서도 효율적이며 안정적인 데이터 전송은 기본적으로 필요한 사안이 되었는데 근본적으로 효율적이고 안정적인 데이터의 전달이 에너지 절감에도 도움이 되기 때문이다. 이에 본 논문에서는 유비궈터스 센서 네트워크에서의 데이터 전송 방법에 따른 효율성과 안정성을 성능 분석을 통해서 비교해 보고자 한다.

• 보건교육건강증진학회지
• /
• 제29권5호
• /
• pp.27-36
• /
• 2012

Objectives: Developing efficient health messages is important for improving health behaviors at a societal level. This study attempts to test a few variables that could constitute the elements for measuring readability of health message. The number of subject-verb relationships in a sentence, placement of jargon, i.e., explication before or after each jargon, and the number of less familiar Chinese characters were manipulated to hypothetically differentiate readability. Methods: In a $2{\times}2$ mixed factorial experiment, 152 college students read two health messages regarding side effect of health functional food and energy drink. The participants' perceived readability was asked, and eight questions were developed to measure the participants' recognition of the health information. Results: Those who read messages manipulated to have high readability rated the message significantly higher than those who read messages with low readability. Also, the former answered the questions more correctly than the latter, implying the association between readability and knowledge acquisition regarding health. Conclusions: Readability is suggested as a factor determining the effect of health messages in affecting the public's health risk perception and relevant behaviors. Further studies to sophisticate the measurement itself and to examine the effect of actual public messages with different readabilities are suggested.