Catálogo de publicaciones - libros

This paper proposes more various key generation algorithms than conventional encryption method, and more secure encryption method that does not keep each symmetric key of key generation algorithm in server. After implementing proposed system, we verify the system using various sizes of video data. We get the fact that proposed system can reduce the delay time of encryption and decryption at the replay of video data.

This paper propose to see how the center based car navigation systems are practical in terms of using real time traffic information and guiding the way with different media of both of the Turn by Turn and the digital map service. The systems have been applied to all the road networks in Korea but the traffic actuated car navigation systems are mainly applicable to the road networks in the Seoul, which has 40 km diameter, including satellite cities. As a result of this, the actual driving tests are conducted in that area. The tests are analyzed using two aspects. The first aspect is that the quality of the information using the car navigation systems can be acceptable to the customers in around 80 percentage of a statistical level. The other is if the user- friendly interface is relatively helpful to the customers while they are driving a car. The result shows that the route displayed on the TFT LCD helps the drivers to understand which way they have to take.

We propose analytic model of the delay of the Slotted ALOHA protocol with Binary Exponential Backoff (BEB) as a collision resolution algorithm in mobile multimedia networks. We verify the proposed analytic model using the computer simulation. In numerical results, our proposed method show correct analytic model and has better performance results than previous methods in mobile multimedia networks.

Detecting network address translation is helpful for network administrators to enhance the network security. Current network address translation detection approaches can not work effectively in all scenarios. In this paper, a new detection scheme ImNatDet utilizing instant messaging information is presented, a case study based on characters of MSN Messenger is analyzed, and related security issues are discussed. This paper also indicates that characters of instant messaging applications can be used to detect users’ privacy information.

At the transition from a tangent section to a curved section, it is possible for a following vehicle with adaptive cruise control in car-following mode to lose track of the lead vehicle. This occurs because the lead vehicle enters the curve and its path diverges from the axis of the following vehicle, yet the following vehicle does not yet have lateral acceleration information that would induce its range sensor to bend according to the curvature of its own path. This is a temporary situation, but one that could have an impact on cruise control safety and appropriate algorithms. In this paper, the conditions of time and distance that produce this circumstance are derived. Examples are given using typical values of roadway and vehicle parameters. Finally, some conclusions regarding possible solutions are offered.

Until a recent date all telephony connections are set up via circuit switching. Advances in networking technology have made it possible for the Internet evolves into a Broadband convergence Network (BcN) and provides various services including Internet Protocol (IP) telephony over high-speed IP networks. Voice-over-IP (VoIP) uses packetized transmission of speech over the Internet. In order for the Internet to realize a profit as traditional Public Switched Telephone Network (PSTN), it must provide high quality VoIP services. The VoIP metrics report block of Real-Time Transport Protocol Control Protocol Extended Reports (RTCP XR) can be applied to any one-to-one or one-to-many voice application for which the use of RTP and RTCP is specified. However, RTCP XR only defines packet type to convey information that supplements the six statistics that are contained in the report blocks used by RTCP’s Sender Report (SR) and Receiver Report (RR) packets. Our objective in this paper is to describes a practical measuring framework for end-to-end QoS of packet switched voice in an IP environment including Packet Loss Concealment (PLC) techniques. It includes concepts as well as step-by-step procedures for setting up components, creating session, measuring packetized voice streams over IP networks.

It is very crucial in the field of security control to acquire the capability of promptly coping with various threatening elements in cyber world such as vicious worms, virus and hackings that cause enormous damage and loss across the nation within a rather short term period like the large scale network paralyzed by vicious traffic, disturbance of electronic commerce, etc. As such, it can be the fundamental measure on these sorts of threats to establish the new method of detecting the similar threats as well as to reinforce the user’s recognition of security. The purpose of this study is to analyze the problems in the existing IDS and TMS, which are monolithic in terms of detection method, and further to suggest the improved detection method and HOIDS system which is recently introduced and in test operation.

It is widely accepted that the coverage with high user densities can only be achieved with small cell such as Micro / Pico-cell. The smaller cell size causes frequent handoffs between cells and a decrease in the permissible handoff processing delay. This may result in the handoff failure, in addition to the loss of some packets during the handoff. In this paper we propose new handoff control scheme in the next generation mobile communications, in which the handoff setup process is done in advance before a handoff request by predicting the handoff cell based on mobile terminal’s current position and moving direction.

Wireless communication technology has been introduced in the field of Intelligent Transportation Systems (ITS) in the past decades, and its applicability has been widely expending. Feasibility of the IR-DSRC based vehicle detection systems in measuring vehicle speed was tested as a possible alternative of the conventional inductive loop based systems requiring high construction and maintenance cost. It was found from the field test that the speed data from the IR-DSRC detection systems were statistically identical to the ones from the loop based systems at 95% confidence level.

Ubiquitous Sensor Networks (USN) environment is composed of dense nodes of Ad-Hoc network structure which has small size node, low power and low calculation ability. Sensor nodes have constraints in operation which small size and distribution features so that they should be operated using low power. In this paper we propose a grid computing scheme to solve limited energy problems which can maintain the energy consumption as a same level though measuring remain energy with analyzing energy consumption of nodes. We confirm the improvement of survival time of entire nodes and less variation of topology in case of our proposed scheme through simulation.