• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.382-384
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• 2008

D-TRS is a method of wireless communication. This method will be able to use several frequency for multiple user used chanel together. TETRA of D-TRS technology is not rented network. Using TETRA network has the strong point which cost better than CDMA network of rental network. Master server of SCADA(Supervisory Control And Data Acquisition) system is realtime supervise control and a data acquire the control system or the RTU(Remote Terminal Unit). The present paper is developed and proposal the gateway platform for electronic power backbone network based on D-TRS. This gateway platform is converted DNP3.0 messages with TETRA PDU and converted TETRA PDU with DNP3.0 messages. Master server and FRTU will be able to send and receive DNP3.0 message via TETRA network using this gateway platform.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.22-29
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• 1999

In video-on-demand systems, movies are striped across the disks of the array in a video server to support multiple access. The blocks of the movies have to be placed carefully on the disks of the array in a video server in order to avoid load imbalance across these disks as well as to achieve maximum utilization of both space and bandwidth of these disks. This paper proposes a movie placement method called the GARR (group-alternation round-robin) that is based on the dynamic disk striping method considering the popularity of movie. The GARR uses group-alternation as movie selection policy and round-robin as data placement policy, where group-alternation allocates popular movie and unpopular movie groups to disks alternately. The performance of the GARR is evaluated by simulations.

• Journal of Astronomy and Space Sciences
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• v.28 no.3
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• pp.241-252
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• 2011

A simulated network protocol provides the capability of distributed simulation to a generic simulator. Through this, full coverage of management of data and service handling among separated simulators is achieved. The distributed simulation environment is much more conducive to handling simulation load balancing and hazard treatment than a standalone computer. According to the simulated network protocol, one simulator takes on the role of server and the other simulators take on the role of client, and client is controlled by server. The purpose of the simulated network protocol is to seamlessly connect multiple simulator instances into a single simulation environment. This paper presents the development of a simulated network (simNetwork) that provides the capability of distributed simulation to a generic simulator (GenSim), which is a software simulator of satellites that has been developed by the Korea Aerospace Research Institute since 2010, to use as a flight software validation bench for future satellite development.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.317-323
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• 2001

Traditional configuration management involves complex labor-intensive processes performed by experts. The configuration tasks such as installing or reconfiguring a system, provisioning network services and allocating resources typically involve a large number of activities involving multiple network elements. The network elements may be associated with proprietary configuration management instrumentation and may also be spread across heterogeneous network domains thereby increasing the complexity of configuration management. This paper introduces an architecture for the self-configuration of networks (SELFCON). The proposed architecture involves a directory server, which is uses to maintain configuration information. The configuration information stared in the directory server is modeled using the standard DEN specification thereby allowing effective exchange of network, system and configuration management data among heterogeneous management domains. SELFCON associates configuration intelligence with the components of the network, rather than limit it to a centralized management station. The network elements are notified about related changes in configuration policies, based upon which, they perform self-configuration. SELFCON is able to provide automation of configuration management and also an effective unifying framework for enterprise management.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.165-172
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• 2016

This paper presents an implementation of a live audio streaming system using the Raspberry Pi 3 embedded computer. This system is a live streaming system not file-based streaming. This is a push streaming system which converts the incoming analog audio signal to digital samples and broadcasts them to multiple connected users concurrently. Since the server software is developed in Java language, it can be installed on any other embedded computers without any modification. We concluded that ESCatcher can service live streaming about 60 users concurrently through calculations and experiments, And also we achieved the delay time of a little bit more than 40ms between arrival of audio source and play on the android device.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.33-41
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• 2016

Big data management is becoming an increasingly important issue in both industry and academia of information science community today. One of the important categories of big data generated from software systems is log data. Log data is generally used for better services in various service providers and can also be used to improve system reliability. In this paper, we propose a novel big data management architecture specialized for log data. The proposed architecture provides a scalable log management system that consists of client and server side modules for efficient handling of log data. To support large and simultaneous log data from multiple clients, we adopt the Hadoop infrastructure in the server-side file system for storing and managing log data efficiently. We implement the proposed architecture to support various client environments and validate the efficiency through measurement studies. The results show that the proposed architecture performs better than the existing logging architecture by 42.8% on average. All components of the proposed architecture are implemented based on open source software and the developed prototypes are now publicly available.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.38-44
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• 2013

In this paper, we designed and implemented a mobile video transmission device with 1080i resolution and 30fps frame rate using wireless multi-access technologies. The video acquisition delay time of 16us and jitter of 21ms for this equipment were obtained, respectively. The device is designed to access various communication networks. In order to evaluate the performance of its video transmission capability, a server and monitoring viewer are implemented. In the performance test using LTE network, 211ms delay time was obtained at 3Mbps transmission. Rendering of 1fps frame rate at the 265kbps transmission was confirmed for the transmission test using Inmarsat network.

• Journal of Convergence Society for SMB
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• v.6 no.3
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• pp.37-41
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• 2016

In this paper, we propose a fire alarm system that utilizes Wi-Fi to alarm multiple people at once. This system, based on Arduino, uses smoke, flame and temperature sensor units to sense fire and send detection data to a server via wireless communication system. The server uses stored data to relay current fire situations gathered from nearby sensors to smartphones. It also automatically reports the fire using location data from sensors. Using this system, we were able to retrieve fire alarm from sensors via push notification of our smartphone. We also confirmed the establishment of linkage with sensors and automatic report of fire via SMS. From this result, the possibility of sending real-time notifications via the Internet toward nearby smartphones about disasters such as conflagration has been proven to be feasible.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.29-39
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• 2011

The appointment system is widely used to facilitate customer access to service in many industries including healthcare and others. Because of its importance, much research has investigated how to build an effective appointment policy under various environments. However, most research has considered a single-server service system. The objective of this work is to evaluate several appointment policies in a two-stage service system in which multiple servers are available and build separate appointments at the second-stage. In such a system, we propose and evaluate the staggering appointment policy. Simulation experiments indicate that the proposed staggering appointment policy outperforms other traditional appointment policies in terms of customer waiting time, server idle time, and the number of customers who are later to scheduled appointments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.547-549
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• 2010

In this paper, we propose context-aware system for semiconductor equipment that acquires information from multiple sensors in indoor environment. This proposed system acquires information from acceleration, pressure, temperature and gas sensors then the acquired information send to server. The data transmitted to server generates an alarm via context-aware algorithm of unit event and multi event. From that result, high-quality real-time monitoring is possible because of the reduced unnecessary alarms, and the efficient management is possible because the surrounding information is recognized at once.