• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.1
• /
• pp.121-131
• /
• 2020

Current traffic information is collected through a loop detector or an image detector. This method is influenced by weather and time, so a traffic information generation system is needed to replace it. A system for generating traffic information using a smartphone in a vehicle is proposed and the performance of the proposed method is verified through the collection rate and the travel time error rate obtained through field tests. In addition, we propose an algorithm for generating intersection traffic information for each direction of rotation, suggest ways to increase the amount of valid information, and confirm the results.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.5
• /
• pp.451-458
• /
• 2016

Urban railway can be divided into ground and underground sections. In particular, the center of the metropolitan has been built mostly underground stations and tunnels. Underground section is difficult to measure the position because GPS signal is unavailable, so it is necessary to apply the indoor positioning technology. For this purpose, we analyzed the positioning technologies which are based on Wi-Fi and mobile base stations. The positing technology for smart phone which uses mobile base station' information is developed in the underground area of urban railway where the core technique is to implement base station ID into the positing technology by considering hand-off point.

• Journal of the Korea Society of Computer and Information
• /
• v.9 no.4 s.32
• /
• pp.221-231
• /
• 2004

Ubiquitous computing is not radical as Mark Weiser argues and includes things. The status of each nation is as follows. Project of America or Europe are practice for computing infra. intelligence of things and space and man-computer co-relation study, otherwise Japan centers the studying of network ubiquity utilizing computing competence. In this thesis I analyzed real status on the ubiquitous computing case study of each nation. and I proposed computing development model. factor, structured value system. five type business and technology model.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.1
• /
• pp.51-56
• /
• 2011

WiBro network technologies developed mainly by Korea are one of very promising 4G technologies. WiBro has been standardized as international standard called Mobile WiMAX, and has been deployed in many countries. Emergency Services in WiBro networks are infrastructure services and will be very essential to induce subscribers from other types of networks. This paper proposes a network architecture for supporting emergency services for WiBro mobile VoIP networks. The proposed architecture is based on WMF's architecture for international compatibilities, and reflects national considerations on interfacing PSAP for domestic compatibilities.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.10
• /
• pp.915-924
• /
• 2012

Though a mobile device is equipped with a number of wireless communication interfaces in general such as Zigbee, Bluetooth, Wi-Fi, 3G, it uses only one interface for a specific service. In this paper, we propose a mechanism of adaptive switching between wireless communication interfaces in order to efficiently use various communication interfaces. Depending on the application service and the characteristics of wireless communication interface, mobile devices select an appropriate wireless communication interface and may switch to another interface during the service. As a result, power consumption can be reduced and the utilization of communication interface can be improved by using this mechanism.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.21 no.1
• /
• pp.15-19
• /
• 1976

Germination and growth of sourgrass, and its competition with improved pasture species, buffelgrass and guineagrass were studied. Optimum germination was obtained under light with alternating temperatures. Germination was stimulated by GA but greatly decreased as moisture .stress was increased. Sourgrass in pastures can be controlled through competition with buffelgrass or guineagrass.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.2785-2792
• /
• 2013

An elevator is driven by the friction between the pulley and wire rope. A balancing counter weight is connected to the elevator car with a wire rope. This structure is essential to drive elevators while it always has weight unbalance problems on each side. The overbalance-ratio of elevators may be an important factor for safety and structural efficiency; however, it is not yet clearly defined in the Requirements of Korea Elevator Inspection. This paper describes these "weight unbalance ratio" for control of elevators to reduce the number of accidents. It includes the analysis of current elevator maintenance situations and also proposes some fundamental improvement schemes for safety.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.3
• /
• pp.573-578
• /
• 2019

Recently, the development of indoor positioning technology, base station positioning, Wi - Fi positioning, and Bluetooth beacon positioning technology have been introduced in buildings and underground space. This paper introduces a technique that enables user-oriented ultra-high precision positioning by adopting a lenticular positioning technology, which is a method in which a user directly locates a user's moving line based on a provider-oriented positioning system and service. Through the study on the implementation of coverage using lenticular stickers, we will discuss how to implement coverage of lenticular stickers, which is one of the most important parts of lenticular positioning technology.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.3
• /
• pp.103-111
• /
• 2009

IEEE 802.16e(Wibro) standard, providing robust mobile realtime data transmission technology, requires of faster and smooth execution of security mechanisms, such as key distribution and user authentications, during base station hopping. In particular, key management mechanisms such as redistribution and regeneration have an impact on digital contents transmission and realtime data transmission, not only in 802.16e environment, but also in typical transmission environment as well. This paper presents traffic management mechanisms designed to realtime digital contents (such as IPTV) transmission efficiency and increase the QoE by utilizing OKTEK methodology.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.12
• /
• pp.1102-1112
• /
• 2012

We propose a cell selection and resource allocation scheme that assigns users to nearby accessible cells in heterogeneous wireless networks consisting of macrocell, femtocells, and Wi-Fi access points, under overload situation. Given the current power level of all accessible cells nearby users, the proposed scheme finds all possible cell assignment mappings of which user should connect to which cell to maximize the number of users that the network can accommodate at the same time. We formulate the cell selection problem with heterogeneous cells into an optimization problem of binary integer programming, and compute the optimal solution. We evaluate the proposed algorithm in terms of network access failure compared to a local ad-hoc based cell selection scheme used in practical systems using network level simulations. We demonstrate that our cell selection algorithm dramatically reduces network access failure in overload situation by fully leveraging network resources evenly across heterogeneous networks. We also validate the practical feasibility in terms of computational complexity of our binary integer program by measuring the computation time with respect to the number of users.