• Journal of Multimedia Information System
• /
• 제1권2호
• /
• pp.111-118
• /
• 2014

The Smart grid refers to the technology that enables efficient usage of electric power by collecting information concerning the power usage and power lines grafting information and communications technology to onto power grids. There are Zigbee, PLC or IEEE 802.11 WLAN MAC as a core technology of the Smart grid, but in this paper, the discussion is focused on the PLC. The PLC is the technology that carries out data communications using power lines and put into practical use in the field of lights or home appliances control recently but PLC-applied communications between electronic devices are rarely seen. For the reason that the PLC uses high-voltage power lines and has a disadvantage of experiencing higher data loss rate caused by the noises produced by going through transformers, the technology is yet to be used in many areas. Nevertheless, the PLC has been studied widely recently in respect that it's the low-cost communication solution for the Smart Metering [1]. Moreover, this technology is emerging as a novel data communication method and discussed as an important technology lately due to the developments of the Smart grid systems and Internet of things (IoT). Thus, in this paper, the results obtained from designing and performing implementation scenario for the PLC-based Smart grid home network system were compared and analyzed with that of IEEE 802.11 WLAN MAC (the foundation technology at Jeju Smart grid Test bed)-based Smart grid home network. Thus, in this paper, OPNET 14.5 PL8, OSI 7 layer, PLC router nodes and PLC nodes had been used for the designing and implementation simulations of both systems. Additionally, QoS was not considered in order to guarantee that all the traffics would not have the same processing priority.

• 유통과학연구
• /
• 제18권3호
• /
• pp.87-97
• /
• 2020

Purpose: The aim of this study is to understand the internal and external responses that consumers experience when they are exposed to an innovative system in retail stores. This study considered the SST(Self-Service Technology) system in a retail setting as a type of functional environmental stimuli and selected a smart shopping cart as an example of SST system. The influences of functional environmental stimuli on consumers' emotional, cognitive, and behavioral responses were examined by applying S-O-R model. In addition, this study attempted to extend the traditional S-O-R model by (a) incorporating personal characteristics variables such as time pressure and perceived crowding and (b) considering not only emotional but also cognitive aspects of consumers' internal responses. Research Design, Data, and Methodology: This study used a video-scenario technique. Participants watched a video about grocery shopping situations using a smart shopping cart and responded to their emotional, cognitive, and behavioral responses. An online survey was conducted using Amazon's Mechanical Turk (N = 185). All participants were US consumers over 20 years old and had been shopping at the grocery store in the last month. Data were analyzed through structural equations modeling with AMOS 20. Results: Test results showed that consumers who perceived higher levels of time pressure and perceived crowding in usual shopping situations were more likely to evaluate the SST system favorably. The results showed that personal characteristics have a significant impact on consumers' evaluation of functional environmental stimuli in retail setting. As consumers evaluated the SST system favorably, they experienced more positive affect and less negative affect during their shopping behaviors. Positive affect led to good service quality inference, which further increased patronize intention. However, negative affect did not show a significant impact on service quality inference, but only on patronize intention. Conclusions: This study attempted to investigate the influence of SST system by extending the traditional S-O-R model. This study classified the SST system as functional environmental stimulus of retail stores and analyzed the effect of stimulus on consumers' internal and external responses. The results of this study showed that the introduction of innovative SST can serve as an effective store differentiation strategy in an increasingly competitive retail environment.

• 터널과지하공간
• /
• 제24권3호
• /
• pp.212-223
• /
• 2014

본 연구에서는 고심도 금속광산갱도에 대한 안정성 해석을 수행하였다. 이를 위해 수압파쇄법으로 암반의 초기지압을 측정하였고, 현장에서 채취한 암석코어로 수많은 실내물성시험을 실시하여 무결암의 물성 값을 산출하였으며, 현장조사를 통해 GSI, RMR 분류법으로 암반을 분류하였다. 암반분류 결과에 대한 시나리오 분석과 확률론적 평가를 통해 광산 갱도를 최상조건, 평균조건, 최하조건으로 구분하였으며, 각 조건별 탄소성해석을 통해 갱도의 안정성을 평가하였다. 또한, 갱도의 형상과 발파손상대의 영향을 고려한 해석을 통해 갱도의 적절한 규격과 지보패턴을 조사하였는데, 본 광산 갱도의 안정성 제고를 위해서는 갱도의 천반 곡률반경을 감소시키거나 천정부 보강이 필요한 것으로 나타났다.

• 한국도로학회논문집
• /
• 제20권2호
• /
• pp.57-65
• /
• 2018

PURPOSES : The study aims to predict the service life of national highway asphalt pavements through deep learning methods by using maintenance history data of the National Highway Pavement Management System. METHODS : For the configuration of a deep learning network, this study used Tensorflow 1.5, an open source program which has excellent usability among deep learning frameworks. For the analysis, nine variables of cumulative annual average daily traffic, cumulative equivalent single axle loads, maintenance layer, surface, base, subbase, anti-frost layer, structural number of pavement, and region were selected as input data, while service life was chosen to construct the input layer and output layers as output data. Additionally, for scenario analysis, in this study, a model was formed with four different numbers of 1, 2, 4, and 8 hidden layers and a simulation analysis was performed according to the applicability of the over fitting resolution algorithm. RESULTS : The results of the analysis have shown that regardless of the number of hidden layers, when an over fitting resolution algorithm, such as dropout, is applied, the prediction capability is improved as the coefficient of determination ($R^2$) of the test data increases. Furthermore, the result of the sensitivity analysis of the applicability of region variables demonstrates that estimating service life requires sufficient consideration of regional characteristics as $R^2$ had a maximum of between 0.73 and 0.84, when regional variables where taken into consideration. CONCLUSIONS : As a result, this study proposes that it is possible to precisely predict the service life of national highway pavement sections with the consideration of traffic, pavement thickness, and regional factors and concludes that the use of the prediction of service life is fundamental data in decision making within pavement management systems.

• 한국컴퓨터정보학회지
• /
• 제14권2호
• /
• pp.215-224
• /
• 2006

VoIP 취약점 중에서 해커 공격의 파급 효과가 가장 큰 스팸공격과 차단에 대한 연구를 하였다. VoIP 서비스에 대한 스팸공격의 시나리오를 작성하고, 콜 스팸, 인스턴트 메시징 스팸, 프레즌스 스팸 공격을 실시한다. 실험실에서 스팸 공격이 성공됨을 증명하고, 사용자의 피해 사실을 확인한다. VoIP 서비스의 스팸 차단 방법의 제안에서 1) 인바이트 리퀘스트 플루드 공격의 차단 2) 블랙/화이트 리스트, 3) 역추적, 4) Black Hole - Sink Hole, 5) 콘텐츠 필터링, 6) 동의 기반 통신, 7) 콜 행위 패턴 조사, 8) 레퓨테이션 시스템을 제안하고 실험한다. 각각의 제안된 차단 방안을 VoIP 네트워크에서 실험하여 스팸차단의 보안 등급을 확인한다. 본 논문의 연구결과를 통하여 VoIP 서비스의 정보보호가 WiBro, BcN에서 확대되어 유비쿼터스 보안을 실현하는데 이바지 할 수 있도록 하겠다.

• 컴퓨터교육학회논문지
• /
• 제6권2호
• /
• pp.81-93
• /
• 2003

본 연구의 목적은 웹기반 GBS(Goal-Based Scenario) 학습 환경에서 학습자-학습자, 학습자-온라인교사간 상호 작용을 계량화시켜 파악할 수 있는 기법으로서 사회 연결망 분석(Social Network Analysis. 이하 SNA)의 가능성에 대해 살펴보는 것이다. 이러한 연구 목적의 달성을 위해 먼저 사회학과 인류학 분야를 중심으로 최근 활발히 활용되고 있는 이 기법의 이론적 및 방법론적 배경을 살펴보고, 이어서 GBS 설계 방식으로 개발된 웹 기반 기업교육 운영 과정에서 생성된 질문방 log file을 활용하여 SNA 변인 중 하나인 중심도(centrality)와 학업 성취도 및 팀활동 기여도 간의 상관관계를 분석하는 탐색적 실증 연구를 실시하였다. 연구의 결과, 중심도는 학업 성취도, 특히 적용 평가 등 고차학습 성취도 및 동료들에 의해 평가된 팀 학습 기여도와 높은 상관이 있음이 나타났다. 결론으로서 이러한 연구 결과가 제시하는 교수 설계적 함의 및 그 제한성에 대해 살펴보고 아울러 향후 연구 방향에 대한 제언을 덧붙였다.

• 한국ITS학회 논문지
• /
• 제17권4호
• /
• pp.112-123
• /
• 2018

자율협력주행 도로시스템은 자율주행차와 V2X 통신으로 연결되어 상호정보를 주고받으며 자율주행차의 안전주행을 지원하는 도로인프라 시스템을 말합니다. 본 연구는 자율협력주행 도로시스템 서비스의 성능평가 방안 제시를 목적으로 하며, 도로인프라에서 자율주행차에 정보를 제공하는 I2V 서비스 중 '작업구간 정보제공 서비스'를 예를 들어, 먼저 서비스에 대한 Use Case 분석과 서비스 성능을 확인하기 위해 필요한 요구사항 및 서비스 범위를 정의하고, 이러한 서비스의 성능평가 수행을 위한 평가시스템을 제안하였다. 또한, 본 연구에서 제안한 평가시스템을 활용하여 '작업구간 정보제공 서비스'의 현장시험을 통해 평가 가능여부를 검증하였다.

• 한국인터넷방송통신학회논문지
• /
• 제13권6호
• /
• pp.37-45
• /
• 2013

본 논문에서는 최근 네트워크를 이용한 온라인 원격 진료 서비스가 논의되고 있는 시점에 맞춰 환자에게 적합한 의료기관을 매칭하는 개인 맞춤형 의료서비스 지원 시스템을 제안한다. 본 시스템을 설계하기 위해 개인 맞춤형 의료서비스 지원 시스템의 요구사항을 파악하여 데이터를 표준화하였고 서버와 클라이언트 구조로 아키텍처를 설계하였다. 또한 설계한 시스템을 구현하기 위해 서버와 클라이언트, 온톨로지 저장소의 구조를 정의하고 시스템을 구현하였다. 본 논문에서 설계 및 구현한 개인 맞춤형 의료서비스 지원 시스템을 테스트하기 위해 가정 사항과 시나리오를 작성하여 테스트를 수행한 결과 환자 증상을 선택하면 선택된 증상별로 진료과가 추론이 되고 환자가 원하는 의료기관의 항목에 따라 1차 추론되 진료과에 맞는 의료기관이 추론이 되는 것을 확인하였다.

• 한국간호교육학회지
• /
• 제22권4호
• /
• pp.549-558
• /
• 2016

Purpose: The purpose of this study was to develop and validate a Nursing Competency Scale in Simulation (NCSS) for nursing students. Methods: A preliminary version of the NCSS of 14 items was derived from the literature. A panel of seven experts reviewed the preliminary version for content validation and developed 15 items scale. A convenient sample of 195 nursing students completed the survey and two evaluators measured the performances of nine teams in a simulation scenario with NCSS. The data were analyzed using exploratory factor analysis, descriptive statistics, independent t-test and Cronbach's alpha. Intraclass correlation coefficient (ICC) was used in order to estimate the degree of inter-rater reliability. Results: An exploratory factor analysis demonstrated that two factor structures of the NCSS explained 51.1% of the total variance. Two factors were named psychosocial skills and cognitive and psychomotor skills. The mean scores of NCSS between third and 4th grade were significantly different providing support for its known-group validity. Cronbach's alpha was .90 and ranged from .79 to .88. The overall ICC for inter-rater agreement was 0.89 (95% CI 0.03 to 0.98). Conclusion: This scale shows preliminary evidence for validity and reliability. It could be a useful instrument for measuring learning outcome in simulation for nursing students' clinical competency.

• 한국도로학회논문집
• /
• 제16권6호
• /
• pp.169-179
• /
• 2014

PURPOSES : This study is to conduct the research on the design principle for the driver's safety and comfort in installing consecutive curves of superhighway. METHODS : Superhighway does not currently exist in domestic area. Thus, this study is conducted by collecting driving behavior usage of 30 people who are involved in the members of the virtual driving simulation. By identifying the distribution characteristics of each scenario in ANOVA & Tukey Test, the distribution are categorized into three groups. RESULTS : In the case of Group A in Section 3 (R2 entry part), lane departure exceeds the safety standard, which means to be risky condition. And then in the case of Group B and C, the lane departure values applying theoretical formula was evenly distributed compared to the proven values. CONCLUSIONS : Based on the result, the continuous curve design principles at superhighway should follow three standards as follow. First, an additional linear part needs to be inserted between two curves. Second, what if inserting the linear part is difficult, it would be better to insert a curve more than 2,000m. Third, R1/R2 ratio should not be over two. This design primarily aims to the safety of the operator. Such road alignment also meets the expectations of drivers, thus, it may help drivers to be compatible and amenable while driving continuous curve in superhighway.