• 농촌지도와개발
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• 제11권1호
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• pp.191-207
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• 2004

This study was focused on the development of greenhouse management and environmental control system using internet. The essence of this system were remote automatic control unit connected with greenhouse environmental control according to the growth stages of crops, The specific objectives of the study were; 1) to analyze need of greenhouse environmental remote control system, 2) to investigate the important functions related to greenhouse management program, 3) to explore the possibility of diffusing the system using internet.The study was carried out through review of related literature and need assessment from the research and extension workers in charge of greenhouse management using questionnaire survey, interview and field study. The results of the study were summarized as fallows: 1) About 89% of respondents responded positively on the need to establish automatic control system using internet. 2) The greenhouse management and environmental control system using internet was possible to control the greenhouse in remote, automatic, and simultaneous manner, and additionally by cellular phone in emergent situation. 3) The system was possible to precisely control the greenhouse environment, and it was able to connect the environmental control data with information on growth of crops. 4) By networking the farmer, extension educator of agricultural technology center and researcher, web based farm consulting was possible through the system. Based on the results of the study recommendations were suggested as follows: 1) Thorough spot inspections and field trials should be performed before the diffusion of this system. 2) The costs of the system installation and maintenance should be moderate. 3) The operation of the system should be simple and easy for tamers to adopt. 4) National support should be made to build better internet infrastructure in rural areas.

• Journal of Communications and Networks
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• 제11권5호
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• pp.518-528
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• 2009

IEEE 802.11 wireless local area network (WLAN) has become the prevailing solution for wireless Internet access while transport control protocol (TCP) is the dominant transport-layer protocol in the Internet. It is known that, in an infrastructure-based WLAN with multiple stations carrying long-lived TCP flows, the number of TCP stations that are actively contending to access the wireless channel remains very small. Hence, the aggregate TCP throughput is basically independent of the total number of TCP stations. This phenomenon is due to the closed-loop nature of TCP flow control and the bottleneck downlink (i.e., access point-to-station) transmissions in infrastructure-based WLANs. In this paper, we develop a comprehensive analytical model to study TCP dynamics in infrastructure-based 802.11 WLANs. We calculate the average number of active TCP stations and the aggregate TCP throughput using our model for given total number of TCP stations and the maximum TCP receive window size. We find out that the default minimum contention window sizes specified in the standards (i.e., 31 and 15 for 802.11b and 802.11a, respectively) are not optimal in terms of TCP throughput maximization. Via ns-2 simulation, we verify the correctness of our analytical model and study the effects of some of the simplifying assumptions employed in the model. Simulation results show that our model is reasonably accurate, particularly when the wireline delay is small and/or the packet loss rate is low.

• 인터넷정보학회논문지
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• 제20권2호
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• pp.51-59
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• 2019

본 논문은 최근 각광받고 있는 전기차위주의 많은 실증 사업 중 충전 인프라와 연계된 충전운영시스템 및 전기요금간의 관계를 데이터 연계 분석하였다. 현 시점에서 앞으로 일어날 전기차 충전 인프라에 대한 급속한 수요의 증가로 말미암아 수요치를 예측한다는 의미에서 다가오는 시대를 미리 준비 할 수 있다. 동시에 시스템 모델링을 사이트를 중심으로 실증하고 도식화하는 일이 선행되어야 할 요소이다. 기존의 소규모 시뮬레이션에 의한 모델링과 운영시스템의 설계는 데이터 연계분석을 기반으로 하였다. 본 논문에서는 최종적으로 새로운 시스템 모델링을 구현하여 실제 차량과 이용자를 대상으로 각 지점과 노드별로 시간에 따른 시분할 데이터로 분석하고자 표준 형식으로 도입하였다. 실제 구현된 전기차 충전 인프라와 운영시스템을 대상으로 데이터 연계분석 중심의 효율성을 증명하고자 하였다.

• 정보보호학회논문지
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• 제31권4호
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• pp.617-635
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• 2021

네트워크에 연결된 사물인터넷(Internet of Things, IoT) 기기는 보안 솔루션이 적용되지 않아 ICT(Information & Communications Technology) 인프라의 심각한 보안 위협으로 전락했다. 더군다나 IoT 기기의 특성상 자원제약이 많아 기존의 보안 솔루션을 적용하기 어렵다. 그 결과 사물인터넷 기기는 사이버 공격자의 공격 대상이 됐으며, 실제로도 사물인터넷 기기를 대상으로 한 악성코드 공격이 해마다 꾸준히 증가하고 있다. 이에 IoT 인프라를 보호하기 위해 여러 보안 솔루션이 개발되고 있지만, 기능이 검증되지 않은 보안 솔루션을 실제 환경에 적용하기엔 큰 위험이 따른다. 따라서 보안 솔루션의 기능과 성능을 검증할 검증 도구도 필요하다. 보안 솔루션이 다양한 보안 위협에 대응하는 방법도 다양하므로, 각 보안 솔루션의 특징을 기반으로 한 최적의 검증 도구가 필요하다. 본 논문에서는 IoT 인프라에 빠른 속도로 악성코드를 전파하는 악성코드 고속 확산 도구를 제안한다. 또한, IoT 인프라에서 확산하는 공격을 빠르게 탐지하고 차단하는 보안 솔루션의 기능과 성능을 검증하기 위해 개발된 악성코드 고속 확산 도구를 이용한다.

• 한국정보처리학회논문지
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• 제6권11S호
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• pp.3229-3242
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• 1999

At recent, the Internet is evolving into the directions which is capable of incorporating stream-type services such as voice and video services due to the remarkable growth of WWW service and the development of new multimedia application services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS-based routing algorithm in order to allow flexible routing by the Internet user's QoS demand and to be applied into wide area networks. In this paper, we presented new routing algorithms for next generation Internet services and made performance evaluations. The proposed algorithms allow the routing by the user's QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of next Generation Internet Services.

• 품질경영학회지
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• 제30권3호
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• pp.168-185
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• 2002

A few recent international surveys reported that Korea ranks the top with respect to the high-speed information and communication network subscription per 100 people in the world. Such infrastructure has been bringing about broad changes in Internet service for both business and individual users. By conducting a questionnaire survey on a moderate size of sample proportional to the population of each region across country, we try to analyze what factors might explain the level of Internet service satisfaction with respect to security, searching, and convenience dimensions. According to the test results, several factors such as sex, age, kind of network lines, usage frequency, e-mail usage, e-shopping, online problem experience might explain the different levels of Internet service satisfaction in the high-speed Internet network. This study might shed a guidance to scholars conducting Internet-related studies and practitioners who plan information policies and business strategies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4123-4144
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• 2016

Vehicular Ad Hoc Networks (VANETs) utilize radio propagation models (RPMs) to predict path loss in vehicular environment. Modern urban vehicular environment contains road infrastructure units that include road tunnels, straight roads, curved roads flyovers and underpasses. Different RPMs were proposed in the past to predict path loss, but modern road infrastructure units especially flyovers and underpasses are neglected previously. Most of the existing RPMs are computationally complex and ignore some of the critical features such as impact of infrastructure units on the signal propagation and the effect of both static and moving radio obstacles on signal attenuation. Therefore, the existing RPMs are incapable of predicting path loss in flyovers and underpass accurately. This paper proposes an RPM to predict path loss for vehicular communication on flyovers and inside underpasses that considers both the static and moving radio obstacles while requiring only marginal overhead. The proposed RPM is validated based upon the field measurements in 5 GHz frequency band. A close agreement is found between the measured and predicted values of path loss.

• 통상정보연구
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• 제4권2호
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• pp.131-153
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• 2002

An information technology revolution is sweeping the world driven by digitalization and tremendous popularity of the Internet. Electronic commerce and trade is the mainstream of this trend, and realization of a cyberspace without physical, spatial, and time restraints has led radical structural changes in international trade. Northeast Asia including Korea, China and Japan is becoming more important as a core economic region in terms of economic growth, intra-regional trade in particular. The introduction to electronic trade system and networks would playa vital role in speeding up trade of commodities, service and information etc. Therefore the study aims to examine a scheme to facilitate international trade in Northeast Asia by establishing information infrastructures. The study begins with reviewing current situation in information infrastructure such as the number of PC, utilization ratio of internet, information network, volume of electronic commerce. It is analyzed that what kinds of obstacles to facilitating electronic trade in Northeast Asian countries in terms of physical infrastructure, institutions, regulations, technologies regarding information exchange among countries. Finally this study presents some suggestions in order to remove the problems currently existed in vitalizing electronic trade.

• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.91-100
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• 2022

Major developed countries are seriously considering smart factories to increase their manufacturing competitiveness. Smart factory is a customized factory that incorporates ICT in the entire process from product planning to design, distribution and sales. This can reduce production costs and respond flexibly to the consumer market. The smart factory converts physical signals into digital signals, connects machines, parts, factories, manufacturing processes, people, and supply chain partners in the factory to each other, and uses the collected data to enable the smart factory platform to operate intelligently. Enhancing personalized value is the key. Therefore, it can be said that the success or failure of a smart factory depends on whether big data is secured and utilized. Standardized communication and collaboration are required to smoothly acquire big data inside and outside the factory in the smart factory, and the use of big data can be maximized through big data analysis. This study examines big data analysis and standardization in smart factory. Manufacturing innovation by country, smart factory construction framework, smart factory implementation key elements, big data analysis and visualization, etc. will be reviewed first. Through this, we propose services such as big data infrastructure construction process, big data platform components, big data modeling, big data quality management components, big data standardization, and big data implementation consulting that can be suggested when building big data infrastructure in smart factories. It is expected that this proposal can be a guide for building big data infrastructure for companies that want to introduce a smart factory.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.73-81
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• 2023

Globalized cities are currently showing changes due to autonomous driving (AD). It is also maximizing globalization connections in cities where autonomous mobility is as complex as AD. The purpose of this study is to reveal that cities that realize AD and mobility will grow into globalized cities. Several cities, including New York and Shanghai, have attempted and are in progress, but failed cities are increasing. Although the technology of AD and the trust of citizens are prioritized, the city that has built the city's infrastructure is expected to be a city that has succeeded in AD. This is because commercialized cities or AVs will become hubs for mobility globalization, excluding rapid climate change or AV companies, and empirical analysis has been conducted that if AVs fail in metropolitan New York due to urban complexity (population density), urban economy size (GRDP), patents, number of consumers, infrastructure public EV chargers, and road quality. It examines whether the realization of AD by region and country affects overall national innovation. As a result, even if AV succeeds in large cities such as New York, Seoul, which has a higher population density (complexity), has a negative meaning, and a more similar Tokyo has a positive meaning. It can be seen that regional research on AV should also be prioritized in large cities such as Shanghai. This means that in order for AV to be realized in each city, the construction of AI infrastructure data must be actively changed to establish globalization of cities for economic growth as autonomous mobility.