• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.177-186
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• 2010

The principal objective of this paper is to develop road design guidelines, especially for managed lane access spacing between the expressway on-ramp (or off-ramp) and managed lane access point. Managed lanes are typically located in the expressway median and are accessed by weaving across the mainlines. The high level of lane-changing activity present in weaving areas affects capacity significantly. One promising tool for the analysis of lane-changing activity is "gap acceptance theory." This paper estimates the capacity of weaving areas based on the estimated degree of traffic turbulence using gap acceptance theory. The degree of traffic turbulence is represented by a function of the probability that lane-changing vehicles can complete their maneuvers successfully in a given weaving distance. In developing road design guidelines based on the developed gap acceptance model, the minimum managed lane access spacing is determined where the capacity with respect to the managed lane access spacing becomes stable.

• ETRI Journal
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• v.39 no.4
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• pp.546-557
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• 2017

In a long term evolution-advanced (LTE-A) system, the traffic overload of machine type communication devices is a challenge because too many devices attempt to access a base station (BS) simultaneously in a short period of time. We discuss the challenge of the gap between the theoretical maximum throughput and the actual throughput. A gap occurs when the BS cannot change the number of preambles for a random access channel (RACH) until multiple numbers of RACHs are completed. In addition, a preamble partition approach is proposed in this paper that uses two groups of preambles to reduce this gap. A performance evaluation shows that the proposed approach increases the average throughput. For 100,000 devices in a cell, the throughput is increased by 29.7% to 114.4% and 23.0% to 91.3% with uniform and Beta-distributed arrivals of devices, respectively.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2000.11a
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• pp.5-24
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• 2000

Access to computers and the internet and the ability to effectively use this technology are becoming increasingly important for full participation in Korea′s economic, education, and social life. In recent years, access to computers and internet has exploded. Unfortunately, there is strong evidence of "digital divide"-gap between those individual and communities that have access to these information technology and those who don′t. This research focus on the elementary school students in Taejon, Korea. We found that there is digital divide among children and also different result between access to information technology and use of contents to information technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.223-234
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• 2011

For advanced database security, various researches and challenges are being done to keep pace with new information technologies. We suggests new extended access control that make it possible to conform security policies even with uncertain context and purpose. There may be a discrepancy between the syntactic phrase in security policies and that in queries, called semantic gap problem. New access control derive semantic implications from context and purpose hierarchy tree and control the exceed privileges using semantic gap factor calculating the degree of the discrepancy. And then, We illustrate prototype system architecture and show performance comparison with existing access control methods.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.31-34
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• 2004

본 논문에서는 현재 위성 DMB 국내 표준으로 채택되어 있는 System E 방식의 Dual Mode 신호 전송에 따른 신호변환시 Time Delay측정 방법에 대해서 제안을 하였다. 제안된 방식의 경우 아날로그 방식이 아닌 디지털 방식으로 정확한 Time Delay 측정이 가능하다. 그리고 위성 DMB Gap Filler System의 입 출력 단자를 통하여 측정이 가능함으로 측정값에 대한 신뢰성 확보가 가능하며 자동측정 방식임으로 측정시 발생될 수 있는 Human Error를 최소화 할 수 있다는 장점을 가지고 있다.

• International journal of advanced smart convergence
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• v.10 no.2
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• pp.37-44
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• 2021

At the time of entering the super-aged society, the health problem of the elderly is becoming more prominent due to the rapid digital era caused by COVID-19, but the gap between welfare budgets and welfare benefits according to regional characteristics is still not narrowed and there is a significant difference in emergency medical access. In response, this study proposes an ICT-based New Normal Smart Care System (NNSCS) to bridge the gap I n health and medical problems. This is an integrated system model that links the elderly themselves to health care, self-diagnosis, disease prediction and prevention, and emergency medical services. The purpose is to apply location-based technology and motion recognition technology under smartphones and smartwatches (wearable) environments to detect health care and risks, predict and diagnose diseases using health and medical big data, and minimize treatment latency. Through the New Normal Smart Care System (NNSCS), which links health care, prevention, and rapid emergency treatment with easy and simple access to health care for the elderly, it aims to minimize health gaps and solve health problems for the elderly.

• Design & Manufacturing
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• v.15 no.4
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• pp.14-23
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• 2021

In this study, we have analyzed the access status and the data usage trend of the public Wi-Fi on the bus, which has not been carried out in the previous studies. The analysis period of this study is 5 months from Nov. 2020 to Mar. 2021. When we compared the access status of Seoul metropolitan and the non-metropolitan region against each region's deployment status ratio, the access ratio of the metropolitan region was higher than the non-metropolitan region, of which the gap was 4.53%. The access for each region showed the growing trend, which was 43.5% on average. The data usage also showed the growing trend, 2.7% on average. Weekly data usage showed the growing trend irrespective of weekdays or weekends. The data usage of the weekdays was 695GB higher than weekends. The data usage during commuting hours including school (7:00~9:00 a.m. and 4:00~6:00 p.m.) was higher than 3,000GB. We can conclude that bus public Wi-Fi was used more actively in non-metropolitan region than Seoul metropolitan region by the office workers and students. The secure access also showed the growing trend. And the secure data usage also showed the growing trend.

• Journal of Digital Convergence
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• v.2 no.2
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• pp.63-76
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• 2004

There is a considerable gap in the level of the Internet access charges among countries because of the history of the Internet use, current status of the Internet infrastructure, the Internet penetration rate, and so on. Low Internet access charge increases the number of the Internet users and the Internet penetration rate, which boosts economic activities. This paper empirically explores the impacts of the internet access charges on economic activities using a cross-country analysis based on data from 76 countries for the year 1998-2001. To this end, several versions of the neoclassical growth models, explicitly including the internet access charges, are estimated with the GDP used for a proxy for economic activities and the level of Internet access charges considered as an input to production. Subject to the appropriate caveats, the results show that the level of the Internet access charges make a significantly negative effect on economic activities. In other words, it is concluded that low Internet access charges of a county increase economic activities and the increased economic activities in turn raise the real income of the county.

• Journal of Korean Library and Information Science Society
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• v.30 no.4
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• pp.279-298
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• 1999

Information gap widens as the information society matures. This paper delineates the factors causing information gap as socioeconomic gap, commercialization of information privation of information means and information explosion. Due to these factors information gap between the information poor and the information rich inevitably widens. To bridge the information gap requires policy efforts that are based on democratic principles. This paper asserts that the public domain of information should be secured to ensure the fair and equal access to information and use of information. It is also argued that the function and role of the public information systems such as public libraries, public schools should be expanded and fortified to ensure the minimum level of fairness and equality in an information society. It is suggested that a public site in a cyber-space might be needed to form public opinions and exchange basic information.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.888-893
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• 2004

This paper proposed a dual actuator using bimorph PZT for information storage device based on prove array NSOM(Near-field Scanning Optical Microscopy). The gap between the media and the optical head should be maintained within the optical tolerance. Therefore, a new actuator having high sensitivity is required. Bimorph PZT, which has fast access time and high sensitivity characteristic, is suitable for this precise actuating system. This paper is focused on derivation of mathematical model of dual bimorph PZT actuator and control algorithm. Hamilton's principle was used for mathematical model. The model is verified by FEA(Finite Element Analysis), and compared with experimental results. Different control algorithms were used f3r two bimorph PZT actuating same direction and opposite direction. The gap between recording media and optical head was controlled within 20nm in experiment.