• International Journal of Computer Science & Network Security
• /
• v.24 no.10
• /
• pp.191-196
• /
• 2024

This paper presents a subfamily of quasi-orthogonal space time block codes (QOSTBC), named Exclusive Conjugate (ECQOSTBC), with full rate, full diversity and simple decoding at the receiver. Our approach estimates feedback constants at the receiver and the transmitter in turn modifies the transmitted symbols based on the estimated constants. This approach is an alternative method to those used in the literature to overcome the challenge of no existing STBC with full diversity and full rate with simple decoding for more than two transmitted antennas. Our simulation results show that the proposed family has better performance in terms of BER-SNR when compared to other codes presented in the literature. Finally, the estimated feedback constants in this work consists of only two real constants.

• Spatial Information Research
• /
• v.17 no.3
• /
• pp.361-370
• /
• 2009

As the increasing interests of spatial information for different application area such as disaster management, there are many researches and development of indoor spatial data models and real-time evacuation management systems. The application requires to determine and optical paths in emergency situation, to support evacuees and rescuers. The optimal path in this study is defined to guide rescuers, So, the path is from entrance to the disaster site (room), not from rooms to entrances in the building. In this study, we propose a time-dependent optimal routing algorithm to develop real-time evacuation systems. The network data that represents navigable spaces in building is used for routing the optimal path. Associated information about environment (for example, number of evacuees or rescuers, capacity of hallways and rooms, type of rooms and so on) is assigned to nodes and edges in the network. The time-dependent optimal path is defined after concerning environmental information on the positions of evacuees (for avoiding places jammed with evacuees) and rescuer at each time slot. To detect the positions of human beings in a building per time period, we use the results of evacuation simulation system to identify the movement patterns of human beings in the emergency situation. We use the simulation data of five or ten seconds time interval, to determine the optimal route for rescuers.

• The KIPS Transactions:PartA
• /
• v.17A no.4
• /
• pp.181-188
• /
• 2010

In this study, we suggest the system to analyze network users' action patterns by using Data-Mining Technique. We installed Network Tap to implement the analysis system of network action and copied the network packet. The copied packet is stored at the database through MainMemoryDB(MMDB) of the high-speed. The stored data analyze the users' action patterns by using Data-Mining Technique and then report the results to the network manager on real-time. Also, we applied the standard XML document exchange method to share the data between different systems. We propose this action pattern analysis system operated embedded type of SetToBox to install easily and support low price.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10c
• /
• pp.49-51
• /
• 2003

Developers of network games have used several prediction techniques for hiding transmission delay to support the real­time requirement of network games. Nowadays many researches that are related with network game are in progress to solve delay problems more radically, such as to propose new routers architecture and transport protocols suitable to characteristics of network game traffic. So for these advanced researches the tasks to grasp the traffic characteristics of a network game are needed. In this paper we aimed to capture the traffic of MMORPG and present the statistical analysis of measured data. The measurement and the analysis were accomplished with the server of 'Lineage' that regarded as the most successful MMORPG. Next, we have implemented a traffic generator that reflects the characteristics of MMORPG and shown that the trace generated by MMORPG traffic generator had identical characteristics with actual traffic using statistical testing method. We expect that this traffic generator can be used in many researches related with a network game.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.10
• /
• pp.1018-1023
• /
• 2010

The CAN (Controller Area Network) system is the most dominant protocol for in-vehicle networking system because it provides bounded transmission delay among ECUs (Electronic Control Units) at data rates between 125Kbps and 1Mbps. And, many automotive companies have chosen the CAN protocol for their in-vehicle networking system such as chassis network system because of its excellent communication characteristics. However, the increasing number of ECUs and the need for more intelligent functions such as ADASs (Advanced Driver Assistance Systems) or IVISs (In-Vehicle Information Systems) require a network with more network capacity and the real-time QoS (Quality-of-Service). As one approach to enhancing the network capacity of a CAN system, this paper introduces a CAN system with dual communication channel. And, this paper presents a distributed message allocation method that allocates messages to the more appropriate channel using forecast traffic of each channel. Finally, an experimental testbed using commercial off-the-shelf microcontrollers with two CAN protocol controllers was used to demonstrate the feasibility of the CAN system with dual communication channel using the distributed message allocation method.

• Journal of Korea Multimedia Society
• /
• v.13 no.1
• /
• pp.10-16
• /
• 2010

As the study of ubiquitous computing environment has been very active in recent years, the senor network technology is considered to be a core technology of it. This wireless sensor network is enabled to sense and gather data of interest from its surroundings by sensor nodes applied in physical space. Each sensor node structuring the sensor network is demanded to execute the required service using limited resources. This limited usage of resources requires the sensor node to energy-efficiently perform in building wireless sensor network, which enables to extend the entire network life. This study structures a system able to monitor changing environment data on a real-time basis using a computer remotely as it energy-efficiently gathers and sends environment data of specific areas.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.167-172
• /
• 2001

This paper deals with the network interface of research and observation instruments in the oceanographic research vessel, an establishment of related database for measured information. The system is implemented to integrated communication network system which allows to effective survey and real time-based observation through the establishment of GUI(Graphic User Interface). The system also consists of the LAN systems and serial interface with chemical, physical, biological, and environmental relations. And, other network service, vessel data service for data communication between vessel and earth station using the INMARSAT-B, and network service(WWW, BBS, E-Mail etc.) are needed for integrated communication network system.

• Journal of information and communication convergence engineering
• /
• v.7 no.3
• /
• pp.314-322
• /
• 2009

Nowadays, maritime communication systems need high data rate, reliability, and consistency in order to equivalently provide navigating ships with diverse multimedia services as in terrestrial communication systems. For this purpose, we conceptualize and design the maritime network for ships equipped with a multiband communication system which cost-effectively supports multimedia services according to several radiofrequency bands, such as HF, VHF, and satellite frequencies. We also introduce two service scenarios targeted for the maritime network; ship multimedia service (SMS) and real-time maritime logistics location tracking (RML2T). In addition, we specify related works according to three lower network layers (i.e., physical, data-link, and network layers) upon designing the network.

• Journal of Navigation and Port Research
• /
• v.28 no.5
• /
• pp.435-441
• /
• 2004

This paper deals with modelling and identification of a shipboard stabilized satellite antenna system using the optimal neural network structure. It is difficult for shipboard satellite antenna system to control and identification because of their approximating ability of nonlinear function So it is important to design the neural network with optimal structure for minimum error and fast response time. In this paper, a neural network structure using genetic algorithm is optimized And genetic algorithm is also used for identifying a shipboard satellite antenna system It is noticed that the optimal neural network structure actually describes the real movement of ship well. Through practical test, the optimal neural network structure is shown to be effective for modelling the shipboard satellite antenna system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.7
• /
• pp.1377-1384
• /
• 2015

In this paper, a resource management scheme for preventing the video frame loss in the presence of network congestion is proposed. WiMedia protocol is suitable for the application that supports the real-time multimedia service in the ship area network since it supports high speed data transfer. However, network congestion causes the degradation of video quality, since WiMedia standard discards video frames regardless of importance of video frame. Therefore, a resource management scheme for WiMedia network is proposed in this paper. The proposed technique can intelligently treat the network congestion, and solve the degradation of video quality.