• Journal of Internet Computing and Services
• /
• v.1 no.1
• /
• pp.95-104
• /
• 2000

In general cases, the conventionl Internet connected to a terrestrial network is too slow to transmit large medical images. To overcome this low speed problem of the Internet, we have developed asymmetric satellite data communication system (ASDCS) as a fast satellite Internet communication method. The ASDCS uses a receive-only satellite link for dat delivery and a terrestrial network for control communication. The satellite communication link we implemented showed the very high-speed performance compared to the terrestrial link. Using ASDCS, the satellite Internet communication was 10-30 times faster than the conventional terrestrial Internet link. Also we have developed a Web-based Telemedicine system that can access every permitted server of hospital via the Internet. Java programming techniques were used to make our system and it can access and retrieve medical information and images through only public web browser such as Netscape TM without additional specific tools. To increase the transmitting speed of our Telemedicine system, JPEG method was used. In conclusion, we were able to develop a fast and public Telemedicine system using the proposed ASDCS and Web technology. ASDCS technology increased the speed of the conventional Internet and Web technology extended the scope of use for Telemedicine system from intrahospital to public use.

• Journal of information and communication convergence engineering
• /
• v.6 no.3
• /
• pp.239-244
• /
• 2008

Cargo tracking issue on train transportation is challenging area because of long distance haulage, theft, terror attack and customer service. This paper aims at evaluating various cargo tracking systems in terms of cost and technology. The contents of this paper consist of the research trend of cargo tracking system in the railroad transportation and reviewing of technical alternatives in cost and service side. GNSS and RFID are reviewed as location tracking technology, Internet and Satellite technology like INMASAT and Low Earth Orbit are also reviewed as communication infrastructure. This paper selects cost and service factors in two alternatives of GNSS-Satellite and RFID-Internet, among GNSS-Internet, GNSS, Satellite, RFID-Internet, RFID-Satellite and evaluate each alternative in terms of cost and service. In a result, in terms of cost, RFID-Internet type is superior to GNSS-Satellite type, but in service GNSS-Satellite type is preferred to RFID-Internet in point of area coverage and service coverage.

• International Journal of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.128-133
• /
• 2023

Satellite based communication is networks in which users in a wide area can access without wired-based ground infrastructure. In particular, the need is emerging due to the recent Ukraine-Russia war. Satellite network systems acquire data that is difficult to observe on Earth as well as communication networks and are also used for research and development, which allows additional data to be produced. However, due to the nature of communication networks existing in outer space, certain vulnerabilities are revealed, and attacks based on them can be exposed. In this paper, we analyze vulnerabilities that may arise due to the nature of satellite communication networks and describes current research, countermeasures, and future research directions.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.6
• /
• pp.1638-1658
• /
• 2024

As a crucial development direction for the sixth generation of mobile communication networks (6G), Low Earth Orbit (LEO) satellite networks exhibit characteristics such as low latency, seamless coverage, and high bandwidth. However, the frequent changes in the topology of LEO satellite networks complicate communication between satellites, and satellite power resources are limited. To fully utilize resources on satellites, it is essential to determine the association between satellites before power allocation. To effectively address the satellite association problem in LEO satellite networks, this paper proposes a satellite association-based resource allocation algorithm. The algorithm comprehensively considers the throughput of the satellite network and the fairness associated with satellite correlation. It formulates an objective function with logarithmic utility by taking the logarithm and summing the satellite channel capacities. This aims to maximize the sum of logarithmic utility while promoting the selection of fewer associated satellites for forwarding satellites, thereby enhancing the fairness of satellite association. The problems of satellite association and power allocation are solved under constraints on resources and transmission rates, maximizing the logarithmic utility function. The paper employs an improved Kuhn-Munkres (KM) algorithm to solve the satellite association problem and determine the correlation between satellites. Based on the satellite association results, the paper uses the Lagrangian dual method to solve the power allocation problem. Simulation results demonstrate that the proposed algorithm enhances the fairness of satellite association, optimizes resource utilization, and effectively improves the throughput of LEO satellite networks.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.3249-3252
• /
• 1999

In this paper, we present the Tele-PACS of radiology, which uses the communication network as asymetric satellite data communication system. The asymetric satellite data communication system uses receive-only satellite links for data delivery and PSTN(Public Switched Telephone Network) modem or N-ISDN(Integrate Services Digital Network) for communication. The satellite communication linking shows the very high-speed performance than terrestial linking such as 28.8 kbps modem linking and 56Kbps linking. The satellite linking is 5 - 10 times faster than the 56Kbps linking. We conclude that 1) Satellite networking is currently the cheapest and fastest solution for internet access. 2) Web-based Image-Viewer enables small size hospitals in rural area to connect to central PACS easily and to retrieve the image data reliably. 3) The suggested teleradiology system using satellite networking could be adequate to fast telemedicine and telecare for rural hospitals especially located in geographically isolated areas such as islands.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.557-560
• /
• 1998

In this paper, we presetn the WWW (world-wide-web) base dtelePACS, which uses the communication network as asymmetric satellite data communication system (ASDCS). Web-based telePACS is imple-mented with JAVA language. Through the internet, web-based TelePACS can make it possible for remote hospital or doctor to access PACS data and information easily and cheaply. The ASDCS uses receive-only satellite links for data delivery and PSTN (Public switched telephone Network) modem or N-ISDN (narrow band integrate services digital network) for communication. The satellite communication linking shows the very high-seed performance such as 10-30 times faster than the modem linking.To solve the speed limits of internet, JPEG and wavelet compression methods were adapted in WWW-based TelePACS and were evaluated by PSNR (peak signal-to-noise ratio) and by radiological experts that 10:1 or less JPEG and wavelet compression may be acceptable for diagnostic purposes. Consequently, we get the conslusion that our system is suitable for tele-radiology and telemedicine world widely.

• Journal of Advanced Navigation Technology
• /
• v.13 no.2
• /
• pp.172-177
• /
• 2009

Mugunghwa Satellite N0.1 is fired after operation was 13 years. The establishment of communication satellites, as well as Internet service backbone network the country, including satellite broadcasting services to provide multimedia services to general users and contribute to have a big role. High-speed Internet Access Network was expanded and satellite Internet subscribers Access Network rapidly decreasing, but it also a difficult situation, satellite communications network is still important as a component is located. Launched the first communication satellite to be launched and operated several commercial communications satellite, but satellite communications services and the pace of the system is in place. In this paper VSAT, satellite communications service to provide a service based on the status and problems of the status of operating system and will present alternative policies to solve.

• Electronics and Telecommunications Trends
• /
• v.39 no.3
• /
• pp.36-47
• /
• 2024

Low Earth Orbit (LEO) satellite communications has become a crucial technology for next-generation communication networks owing to its hyperconnectivity capabilities. We examine the progress and application areas of LEO satellite communication services. The LEO satellite communication industry has transitioned from being predominantly driven by governments and institutions to being led by the private sector, following the trajectory of the NewSpace movement. Leading corporations such as SpaceX Starlink and Eutelsat OneWeb are deploying LEO satellite networks to offer internet services, while Telesat is preparing to establish its satellite communication network. LEO satellite communications is expected to have a major impact on various sectors of society, particularly for upcoming sixth-generation services. Therefore, the South Korean government must promptly formulate policy support strategies aimed at invigorating the LEO satellite communication industry. This can be achieved through initiatives such as bolstering research and development and extending corporate assistance.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.1
• /
• pp.45-52
• /
• 2015

Since the broadcast message in satellite signals the security of the data is extremely poor compared to other communication technologies such as the broadcast signal. Thus, encryption of the communication satellite has become a very important issue, an analysis of the communication performance of a general service is always required. In this paper, In order to analyze the encrypted communication the turbo code in an IP-based satellite communication applies the code rate compatible punctured and The wireless channel in consideration of the actual satellite communication was constructed by placing a weight on the Rayleigh fading and the Rician fading two channels. Retransmission-based error control scheme were constructed in the best performance of H-ARQ Type-II, III scheme of a number of ways that are recently considered. we analyzed the effects of normal service against a satellite communication network The security services were configured with encryption algorithms AES, ARIA (CTR, CBC mode).

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.6
• /
• pp.189-197
• /
• 2012

In this paper, we propose an optimal path search algorithm that applies the received signal strength between a mobile device and a satellite. Because the common path search algorithm is only based on the shortest path search, it is difficult to provide stable multimedia services for the satellite mobile devices. The proposed algorithm provides the stable communication environment for the satellite mobile devices based on received signal strength. In Satellite communications, changes in the radio quality are severe depending on the receiving environment. Therefore, an accurate analysis of the receiving environment characteristics is very important for providing stable multimedia services of satellite communications. The causes of radio attenuation are atmosphere attenuation, vegetation attenuation and buildings attenuation. These factors were applied to analyze the received signal strength. The proposed algorithm can search the optimal path in urban for stable satellite multimedia services.