• Journal of Communications and Networks
• /
• v.14 no.6
• /
• pp.682-691
• /
• 2012

Key agreement protocol is a fundamental protocol in cryptography whereby two or more participants can agree on a common conference key in order to communicate securely among themselves. In this situation, the participants can securely send and receive messages with each other. An adversary not having access to the conference key will not be able to decrypt the messages. In this paper, we propose a novel identity-based authenticated multi user key agreement protocol employing a symmetric balanced incomplete block design. Our protocol is built on elliptic curve cryptography and takes advantage of a kind of bilinear map called Weil pairing. The protocol presented can provide an identification (ID)-based authentication service and resist different key attacks. Furthermore, our protocol is efficient and needs only two rounds for generating a common conference key. It is worth noting that the communication cost for generating a conference key in our protocol is only O($\sqrt{n}$) and the computation cost is only O($nm^2$), where $n$ implies the number of participants and m denotes the extension degree of the finite field $F_{p^m}$. In addition, in order to resist the different key attack from malicious participants, our protocol can be further extended to provide the fault tolerant property.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.12B
• /
• pp.1251-1258
• /
• 2010

Orthogonal Frequency Division Multiplexing (OFDM) has been investigated as promising technology for future broadband communication. In this paper, we propose a power allocation algorithm for a frequency selective fading channel. However, many investigated algorithms that perform high computation overhead are not appropriate for sensor network systems due to hardware limitations. The proposed algorithm significantly reduces computational overhead and satisfies the power budget. Throughput of the algorithm is comparable to the optimum solution. Simulation results support the claim stated.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2448-2450
• /
• 2002

In recent years, it has been a worldwide trend that many power utilities gave their attention to develop and operate their power plants, substation and distribution systems. Following this trend, KEPCO(Korea Electric Power Corporation) has developed many electric automation systems with various communication networks. It has been natural that the automation systems are just focused on to remote devices when they come to be designed. But, we have to shirt the focus to the automation system itself. There are many problems in maintenance and integration of the automation systems. When an automation system can't control some remote devices, there is no way to get why and which part(Master, Network, Master-side Modem or Remote-side modem, Remote Device, etc.) of the system has problems. Moreover the system just directly links to another automation system. If the system has to link many systems, it needs the linker per each systems. So, we need a new concept to resolve that problems, and develop the Intelligent and Integrated Gateway(IIG) for the automation systems for easy maintenance and integration.

• Journal of the Korea Society for Simulation
• /
• v.15 no.4
• /
• pp.41-50
• /
• 2006

The agent system for managing various equipments constituting communication networks is usually started to be developed after completing real resources or can be developed using network management platform independent from real resources. In this paper, we design real resource simulator which can perform in advance the function of real resources without real resources. The real resource simulator performs the role of automatically generating specific attribute value and informing it according to the specified random function. Moreover, in this paper, we design E-GDMO grammar in which the grammar for simulation is added to the existing GDMO grammar and its E-GDMO compiler to perform real resource simulator.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.4
• /
• pp.139-150
• /
• 2009

Authentication and key exchange are fundamental for establishing secure communication channels over public insecure networks. Password-based protocols for authenticated key exchange are designed to work even when user authentication is done via the use of passwords drawn from a small known set of values. There have been many protocols proposed over the years for password authenticated key exchange in the three-party scenario, in which two clients attempt to establish a secret key interacting with one same authentication server. However, little has been done for password authenticated key exchange in the more general and realistic four-party setting, where two clients trying to establish a secret key are registered with different authentication servers. In fact, the recent protocol by Yeh and Sun seems to be the only password authenticated key exchange protocol in the four-party setting. But, the Yeh-Sun protocol adopts the so called "hybrid model", in which each client needs not only to remember a password shared with the server but also to store and manage the server's public key. In some sense, this hybrid approach obviates the reason for considering password authenticated protocols in the first place; it is difficult for humans to securely manage long cryptographic keys. In this work, we introduce a key agreement protocol and a key distribution protocol, respectively, that requires each client only to remember a password shared with its authentication server.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.4
• /
• pp.25-31
• /
• 2015

Smart healthcare environments which merge medical and IT technology are getting ready for the third generation centering EHR from current second generation. As a basic technology for the introduction and activation of EHR systems it requires heterogeneous network interworking techniques between various wired and wireless medical devices. Interworking technology for heterogeneous network among various medical devices is needed to introduce EHR system. The heterogeneous network interworking technology is needed for construction of a reliable data system to convert each of unstructured data into structured data. Therefore, in this paper, we identify the domestic and international trends of smart medical field and analyze the characteristics of wired and wireless communication technology that is used in a heterogeneous network. and also suggest requirements needed for interworking technology and provide interworking technology based on them. we expect that proposed method which is designed for smart healthcare environments would provide a basic architecture needed for third smart medical technology generation.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.9 no.1
• /
• pp.9-23
• /
• 2013

In recent days, there are many researches of wireless LAN services as the communication environment of wireless LAN are so improved that a lot of services are available in wireless environments. The frequency of the wireless LAN is a general resource that can be used to everyone without any permission. Many technologies using this ISM (Industry Science Medical) frequency band are developed fast and widely. But, as many devices use the same frequency band at th same time, the service quality is degraded and the speed of the service rate id degraded by the result of the interference. For overcome this problem, we must provide the new technology of the mobile devices and a new cell design scheme for obtaining maximum throughput that considering the wireless environments effectively. In this paper, we explain the main technology at the IEEE 802.11n environments and proposes the optimal cell design and reference model for gaining maximum performance to many mobile devices at the same time by investigating real environment testing results.

• KEPCO Journal on Electric Power and Energy
• /
• v.2 no.2
• /
• pp.245-251
• /
• 2016

Despite the exponential throughput improvement in mobile communications systems, their ability to satisfy requirements of state-of-the-art and future applications of advanced metering infrastructure (AMI) is still under investigation. Challenges are mainly due to the inadequacy of third generation partnership project (3GPP) networks to support large amounts of devices simultaneously, while the number of AMI end-devices and the frequency of their data transmission increase with new AMI-based applications. In this introductory survey, innovative and future AMI applications and their communication requirements are first reviewed. Then, we identify challenges of 3GPP long term evolution (LTE) in enabling future AMI applications. More importantly, the latest improvements to LTE-A standard release 12 and 13 are reviewed and analyzed with regards to their potential to improve the quality of LTE-enabled AMI. It is found that 3GPP enhancements on machine type communications (MTC) standards will significantly enhance AMI communications. Beyond MTC specifications, non-MTC-specific enhancements such as carrier aggregation and multi-connectivity for user equipment will also contribute greatly to improving reliability and availability of AMI devices. The paper's focus is towards improved backhaul support for innovative and future AMI applications, beyond traditional automatic meter reading.

• Journal of Biomedical Engineering Research
• /
• v.18 no.4
• /
• pp.381-388
• /
• 1997

In this paper, we present the design and implementation of the interbed network communication protocol, which links patient monitors, central stations, DB servers, and clinical workstations together in a patient monitoring system. We describe the requirements to be met thor real-time patient monitoring, propose 2 services Patient Locator Service(PL:7) and Remote Patient Monitoring Service( RPMS). PLS provides the information about how many patients are currently being monitored and where they are located, while RPMS allows the doctors to monitor their patients'vital sign in real-time. The messages for the services, their formats and exchange scheme are also presented with a whole picture of how they are implemented. We adopted the object-oriented programming paradigm in all the analysis and design processes. In the experiment performed in a real clinical setting, the services turned out to meet all the requirements needed for real-time patient monitoring.

• Journal of the Korean Society of Systems Engineering
• /
• v.2 no.2
• /
• pp.45-50
• /
• 2006

Tilting technology is to tilt the train on the curve in order to minimize centrifugal force to passengers and to improve the speed within the limits of passenger's comfort and safety. According to reports from other countries, there is 15~30% speed improvement compared to the conventional trains. Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative applications with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. TTX_PDM is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.