• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.258-261
• /
• 2000

In this paper, the design of Binary FSK Using Cellular Oscillator Network architecture is newly introduced and analyzed. With its easy frequency controllability and MHz range of quadrature signals, the Cellular Oscillator Network can be used in RF communication systems. Binary Frequency Shift Keying can also be implemented through digital loop-path switching. This FSK model is simulated and proved with typical 3V, 0.5$\mu\textrm{m}$ CMOS N-well process parameters.

• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.13-16
• /
• 2000

Recently, with the advent of satellite communication technologies, the network access service through satellites has emerged as an alternative to existing ones. Of satellite access services including multimedia services, the high speed internet access service will be one of the important services. Particularly, the efficient transportation of real time internet traffic seems very essential. The aim of this research is to examine the applicability of the IETF RTP protocol in the satellite access network. The RTP has been developed for the QoS-met transportation protocol of real time traffic over the existing best-effort internet. This paper summarizes the RTP protocol, and describes the architecture of the implementation of the RTP. And also, the compressed RTP header protocol is discussed for the applicability to the satellite link.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.6
• /
• pp.34-44
• /
• 1996

A transputer is a powerful micro-processor, which can communicate with other processors with its own communication links and can be utilized into a powerful parallel computer system with easy way and low price. However, its usage has been limited to a few people because of its own programming language and complicated user interfaces. This paper presents programming tools to use a transputer system easily. It includes transputer integrated environment which has many developing tools, and transputer manager which can monitor and manage the system and developed programs on it. We also implemented a graphichs application program in order to test the feasibility and funcitonalities of programmers easy access to the transputer networks and visualize the performance status of each processor so that they can write efficient parallel programming codes.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.15-18
• /
• 2004

A high data rate Wireless Personal Area Networks (WPAN) system is a hot issue in wireless communication communities and being standardized. Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM) is one of the candidates for WPAN standard. In this paper, we discuss the PLCP (Physical Layer Convergence Protocol) structure for MB-OFDM. Also we evaluate the performance of two signal detection algorithms, which are the method of cross-correlation with the original preamble and the signed preamble. The latter has a low complexity with a little degradation.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.4 no.3
• /
• pp.210-216
• /
• 2004

In this paper, we propose a noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection with noise power calibration for low power applications. The proposed UWB system achieves good bit error rate performance which is favorably comparable to that of the system using the ideal adaptive threshold, while maintaining simple receiver structure, In addition, low power Analog Front-End (AFE) blocks for the proposed noncoherent UWB transceiver are proposed and verified using CMOS technology. Simulation results on the pulse generator, delay time generator and 1-bit Analog-to-Digital (AID) converter show feasibility of the proposed UWB AFE system.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.109-112
• /
• 2005

In this paper, we propose an improved delay-constrained unicast routing (I-DCUR) algorithm for real-time networks which is based on the delay-constrained unicast routing (DCUR) algorithm. Our I-DCUR algorithm is quite different from DCUR algorithm, because the node will choose the link between the active node and the previous node, and it will replace the original loop path when it detects a loop. Thus, firstly consider to choose the link between the active node and the previous node to replace the original loop path when a node detects a loop. So our algorithm can make the construction of path more efficiently, as compared to DCUR algorithm. We could see that the performance of I-DCUR algorithm is much better than DCUR algorithm in the experimental results. There were over 40% improvement in 100 nodes, 60% in 200 nodes, and 9% reduction of costs.

• International journal of advanced smart convergence
• /
• v.8 no.4
• /
• pp.169-178
• /
• 2019

Due to the characteristics of an ad hoc network without a control center, self-organization, and flexible topology, the trust evaluation of the nodes in the network is extremely difficult. Based on the analysis of ad hoc networks and the blockchain technology, a blockchain-based node-level trust evaluation model is proposed. The concepts of the node trust degree of the HASH list on the blockchain and the perfect reward and punishment mechanism are adopted to construct the node trust evaluation model of the ad hoc network. According to the needs of different applications the network security level can be dynamically adjusted through changes in the trust threshold. The simulation experiments demonstrate that ad-hoc on-demand distance vector(AODV) Routing protocol based on this model of multicast-AODV(MAODV) routing protocol shows a significant improvement in security compared with the traditional AODV and on-demand multipath distance vector(AOMDV) routing protocols.

• International journal of advanced smart convergence
• /
• v.8 no.4
• /
• pp.179-187
• /
• 2019

Vehicular density is usually low in a highway environment. Consequently, connectivity of the vehicular ad hoc networks (VANETs) might be poor. We are investigating the problem of deploying the approximation optimal roadside units (RSUs) on the highway covered by VANETs, which employs VANETs to provide excellent connectivity. The goal is to estimate the minimal number of deployed RSUs to guarantee the connectivity probability of the VANET within a given threshold considering that RSUs are to be allocated equidistantly. We apply an approximation algorithm to distribute RSUs locations in the VANETs. Thereafter, performance of the proposed scheme is evaluated by calculating the connectivity probability of the VANET. The simulation results show that there is the threshold value M of implemented RSUs corresponding to each vehicular network with N vehicles. The connectivity probability increases slowly with the number of RSUs getting larger.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.10
• /
• pp.4781-4803
• /
• 2017

Environmental monitoring systems using Wireless Sensor Networks (WSNs) face the challenge of high power consumption, due to the high levels of multi-hop data communication involved. In order to overcome the issue of fast energy depletion, a proof-of-concept implementation proves that adopting a clustering algorithm in environmental monitoring applications will significantly reduce the total power consumption for environment sensor nodes. In this paper, an energy-efficient WSN-based environmental monitoring system is proposed and implemented, using eight sensor nodes deployed over an area of $1km^2$, which took place in the city of Tabuk in Saudi Arabia. The effectiveness of the proposed environmental monitoring system has been demonstrated through adopting a number of real experimental studies.

• ETRI Journal
• /
• v.37 no.1
• /
• pp.186-196
• /
• 2015

In resource-constrained, low-cost, radio-frequency identification (RFID) sensor-based mobile ad hoc networks (MANETs), ensuring security without performance degradation is a major challenge. This paper introduces a novel combination of steps in lightweight protocol integration to provide a secure network for RFID sensor-based MANETs using error-correcting codes (ECCs). The proposed scheme chooses a quasi-cyclic ECC. Key pairs are generated using the ECC for establishing a secure message communication. Probability analysis shows that code-based identification; key generation; and authentication and trust management schemes protect the network from Sybil, eclipse, and de-synchronization attacks. A lightweight model for the proposed sequence of steps is designed and analyzed using an Alloy analyzer. Results show that selection processes with ten nodes and five subgroup controllers identify attacks in only a few milliseconds. Margrave policy analysis shows that there is no conflict among the roles of network members.