• Journal of Korean Society of Transportation
• /
• v.17 no.2
• /
• pp.179-191
• /
• 1999

To device effective freeway traffic flow control strategies and freeway traffic information dissemination strategies, it is very important to estimate real physical queue length on the freeway. Shock wave theory and queueing theory have limitation to be used to estimate the queue length. The primary objective of this study is to develop a reliable method for estimating the physical queue length and level of congestion. Queueing propagation processes were analysed by using such traffic data as main line traffic volume, ramp volume, density. speed, and physical queue length collected by video photographing on Olympic Freeway. As a result of analysis, it has been confirmed that the real queue length can be estimated by using the traffic counts arriving the congested region and passing a bottleneck location. Further more, a reliable method for estimating the level of congestion could be developed on the basis of real-time traffic counts.

• Journal of Korea Multimedia Society
• /
• v.8 no.7
• /
• pp.869-881
• /
• 2005

XML(eXtensible Markup Language) has emerged as a prevalent standard for document representation and exchange on the Internet. XML documents contain information of different sensitivity degrees, so that XML Document must selectively shared by user communities. There is thus the need for models and mechanisms enabling the specification and enforcement of access control policies for XML documents. Mechanisms are also required enabling a secure and selective dissemination of documents to users, according to the authorizations which the users have. In this paper, we give an account of access control model and mechanisms, which XML documents can be securely protected in web environments. We make RBAC Based access Control polices to the problem of secure and selective access of XML documents. The proposed model and mechanism guarantee that the secure use for XML documents through definition of authority for element, attribute, link within XML document as well as XML document.

• Journal of KIISE:Computer Systems and Theory
• /
• v.26 no.12
• /
• pp.1476-1484
• /
• 1999

TV 방송 분야에서 다양한 정보와 상호 작용성을 제공하기 위해서 최근 기존 방송 내용인 A/V 스트림 외 부가정보 방송이 시도되고 있다. 데이타 방송에 대한 기존 연구는 대부분 고정된 내용의 데이타를 방송하는 환경을 가정하고 있어서 그 결과가 방송 내용의 변화가 많은 환경에 부적합하다. 본 논문에서는 데이타에 대한 접근이 반복되지 않을 가능성이 높고 사용자 접근 확률을 예상하기 어려운 상황에서 응답 시간을 개선하는 방안으로 수신 데이타를 무조건 캐쉬에 반입하고 교체가 필요한 경우 다음 방송 시각이 가장 가까운 페이지를 축출하는 사용자 단말 시스템에서의 캐슁 정책을 제안하였다. 제안된 캐쉬 관리 정책은 평균적인 캐쉬 접근 실패 비용을 줄임으로써 사용자 응답 시간을 개선하며, 서로 다른 스케줄링 기법을 사용하는 다양한 방송 제공자가 공존하는 환경에서 보편적으로 효과를 가져올 수 있다.Abstract Recently, many television broadcasters have tried to disseminate digital multimedia data in addition to the traditional content (audio-visual stream). The broadcast data need to be cached by a client system, to provide a reasonable response time for a user request. Previous studies assumed the dissemination of a fixed set of items, and the results are not suitable when broadcast items are frequently changed. In this paper, we propose a novel cache management scheme that chooses the replacement victim based on the remaining time to the next broadcast instance. The proposed scheme reduces response time, where it is hard to predict the probability distribution of user accesses. The caching policy we present here significantly reduces expected response time by minimizing expected cache miss penalty, and can be applied without difficulty to different scheduling algorithms.

• The KIPS Transactions:PartC
• /
• v.15C no.6
• /
• pp.513-522
• /
• 2008

Efficient data dissemination is one of the important subjects for sensor networks. High accessibility of the sensed data can be kept by deploying the data centric storage approach in which data is stored over the nodes in the sensor network itself rather than external storages or systems. The advantage of this approach is its direct accessibility in a real-time without the severe burden on delay and power dissipation on the data path to the external storages or systems. However, if the queries from many users are concentrated to the few nodes with data, then the response time could be increased and it could lead to the reduction of network life time by rapid energy dissipation caused by concentrated network load. In this paper, we propose a adaptive data centric storage scheme based on proxy trajectory (APT) mechanism. We highlight the data centric storage mechanism by taking account of supporting large number of users, and make it feasible to provide high-performance accessibility when a non-uniform traffic pattern is offered. Storing data around the localized users by considering spatial data-access locality, the proxy trajectory of APT provides fast response for the users. The trajectory, furthermore, may help the mobile users to roams freely within the area they dwell.

• Korean Journal of Remote Sensing
• /
• v.28 no.1
• /
• pp.101-116
• /
• 2012

In this paper, we have surveyed the existing architectures of the image processing systems for several meteorological satellites and identified issues which are taken into consideration to construct the advanced meteorological satellite image processing system that is being developed by NMSC(National Meteorological Satellite Center). Most of the existing systems provide the functionalities of the image acquisition, the image processing, the data management, and the data dissemination. Those systems have some common problems with respect to system integration and system maintenance. To solve these problems, NOAA, NWS and ESA suggest new system architectures to improve the existing systems. This paper introduces domestic and foreign approaches to build the satellite image processing systems and studies some issues and strategies for developing those systems.

• Journal of the Korean Regional Science Association
• /
• v.35 no.3
• /
• pp.33-44
• /
• 2019

Smart City is the regional innovation platform that actively utilizes information and communication technologies to diversify city services and improve the performance and quality, hence improving the quality of life and creating new trends of urban activities. Recently, the importance of citizen participation is increasingly emphasized to build smart cities successfully and the Living Lab, an open innovation platform led by users, is taking center stage as a means of realizing it. Accordingly, this study aims to establish the plans for popularizing living labs that provide innovative environments for domestic smart cities. To this end, first of all, political trends related to domestic smart cities' living labs were analyzed, and then, individual characteristics and development processes of the relevant cases were investigated. In addition, in-depth interviews were conducted with the experts of specialized agencies from Netherlands, Finland, and Denmark, etc. which are considered as leading countries in smart cities' living labs. As a result, in order to popularize living labs in domestic smart cities, the following policies were proposed; establishing support systems for commercialization and dissemination, building intermediary support organizations, improvement of laws and institutions, establishing the joint response systems with neighboring areas, etc.

• Journal of Biosystems Engineering
• /
• v.39 no.4
• /
• pp.267-273
• /
• 2014

Purpose: This study was conducted to develop a web-based business management system to ensure the efficient operation and transparent management of government-subsidized agricultural machinery rental businesses. Methods: An MS_SQL2000 database management system (DBMS) solution was utilized in the system for high system compatibility and integrated management. This system was targeted to be compatible with Internet Explorer 6.0 or later and to ensure security and seamless web operations. The system administrator is able to manage a fleet of agricultural machinery, including various inventory codes, release and return, fleet registry, and business performance. Users (farmers) may search the database of rental machinery and reserve them. Results: With respect to rental reservations, the system administrator can manage the fleet by setting the rental status to Approved, Released, or Returned. Through the web, the administrator can also create a database that includes machinery specifications, features, and rental rates. In addition, business performance data can be analyzed using a diverse array of tools to streamline the rental business. Without having to go to the rental office, users can save time and money by searching for and renting agricultural machinery through the information available on the website, including availability, specifications, and rental fees. After deploying the system, the time required to analyze monthly performance and create reports was dramatically reduced from 20 days per person to one day per person. Conclusions: Since 2014, AMRB has been installed and is operating in agricultural machinery rental businesses in 31 cities and counties in South Korea. This study recommends continued expansion and dissemination of AMRB for the systematic and efficient management of agricultural machinery rental businesses.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.822-827
• /
• 2009

As research for URC robot to advance the robot system dissemination and pracical use becomes active, also interest for robot platform and standardization is increasing. However, URC robot middleware does not involve a convergence with IT. Although it seems to be a high connection between robots and IT, the existing middleware has not considered different environments, thus making convergence efforts difficult. The middleware should improve their functions in order to synchronize with IT and to interact through formatted messages. In this paper, we present the necessity of the formatted message in the development of URC platform. In addition, design of the message protocol for the convergence based on the analysis of RUPI, OPC and SECS-II.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.157-165
• /
• 2015

With the ever-improving performance of smartphone cameras and the universal dissemination of cloud services, users can now record and store the events in their daily lives more easily and conveniently. The advent of lifelogging technology has been changing the uses as well as the paradigm of internet services, and emphasizing the importance of services being personalization. As the amount of lifelog data becomes vast, it requires an efficient way to manage and store such vast information. In this paper, we propose an low power lifelog management scheme based on user movement behaviors in wireless networks. In order to reduce the power consumption of a smartphone, in our proposal, frequency of data collection and transfer can be dynamically adjusted based on a user's movement pattern. The analytical results show that our approach achieves better performance than that of the existing lifelog management scheme.

• International Journal of Knowledge Content Development & Technology
• /
• v.9 no.4
• /
• pp.95-114
• /
• 2019

The digitization of traditional medical knowledge in Tanzania will greatly enhance its preservation and dissemination. This is especially important given the challenges facing the current methods of preserving and managing such knowledge. This study presents the requirements engineering approaches and requirements for a web-mobile application that would successfully digitize indigenous knowledge of phytomedicine and relevant practitioners licensing and registration processes. To establish the requirements of such a digital system application, the study sought the opinion of 224 stakeholders whose suggestions were used to analyze and model the requirements for designing such a web-mobile tool. The study was carried out in Arusha, Kagera and Dar es Salaam regions of Tanzania which involved ethnobotanical researchers, herb practitioners, curators from herbaria and registrar officers from Traditional and Alternatives Health Practice Council. Structured interview, survey, observation and document review were employed to find out the basic functional and non-functional requirements for possible designing and implementation a web-mobile application that would digitize indigenous knowledge of medicinal plants. The requirements were modelled using the use case and context diagrams. Finally, the study came up with a list of items for both functional and non-functional requirements that can be used as guidelines to develop a web-mobile application that will capture and document traditional medical knowledge of medicinal plants in Tanzania and, enabling relevant authorities to regulate and manage stakeholders.