• ETRI Journal
• /
• v.36 no.3
• /
• pp.506-509
• /
• 2014

This paper studies the energy efficiency power allocation for cognitive radio networks based on uplink orthogonal frequency-division multiplexing. The power allocation problem is intended to minimize the maximum energy efficiency measured by "Joule per bit" metric, under total power constraint and robust aggregate mutual interference power constraint. However, the above problem is non-convex. To make it solvable, an equivalent convex optimization problem is derived that can be solved by general fractional programming. Then, a robust energy efficiency power allocation scheme is presented. Simulation results corroborate the effectiveness of the proposed methods.

• Electronics and Telecommunications Trends
• /
• v.35 no.3
• /
• pp.76-84
• /
• 2020

Neuromorphic hardware refers to brain-inspired computers or components that model an artificial neural network comprising densely connected parallel neurons and synapses. The major element in the widespread deployment of neural networks in embedded devices are efficient architecture for neuromorphic hardware with regard to performance, power consumption, and chip area. Spiking neural networks (SiNNs) are brain-inspired in which the communication among neurons is modeled in the form of spikes. Owing to brainlike operating modes, SNNs can be power efficient. However, issues still exist with research and actual application of SNNs. In this issue, we focus on the technology development cases and market trends of two typical tracks, which are listed above, from the point of view of artificial intelligence neuromorphic circuits and subsequently describe their future development prospects.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.1
• /
• pp.299-322
• /
• 2020

Vehicular ad hoc networks (VANETs) enable wireless communication between vehicles and roadside infrastructure to provide a safer and more efficient driving environment. However, due to VANETs wireless nature, vehicles are exposed to several security attacks when they join the network. In order to protect VANETs against misbehaviours, one of the vital security requirements is to revoke the misbehaved vehicles from the network. Some existing revocation protocols have been proposed to enhance security in VANETs. However, most of the protocols do not efficiently address revocation issues associated with group signature-based schemes. In this paper, we address the problem by constructing a revocation protocol particularly for group signatures in VANETs. We show that this protocol can be securely and efficiently solve the issue of revocation in group signature schemes. The theoretical analysis and simulation results demonstrate our work is secure against adversaries and achieves performance efficiency and scalability.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.05a
• /
• pp.135-138
• /
• 2004

This paper considers a ring loading problem on RPR(Resilient Packet Ring), where RPR is recommended by IEEE802.17 Resilient Packet Ring working group for data optimized networks without the requirements of provisioning circuits. RPR is well suitable for metropolitan area network with two counter-rotating rings that multiple stations share the bandwidth, where the data and its corresponding control traffic is transmitted to the two opposite directional ring, respectively. One of the major concerns on RPR is to provide fairness among traffic requirements. The paper discusses several fairness measures and analysis ring loading problems for the fairness.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.1
• /
• pp.87-96
• /
• 1997

As the society features evolve to information society, some advanced countries promote to construct the gigabit information and communication networks, to develop system software to operate these networks, and to develop application software to help end-user-daily-life as information infrastructure. In this paper, we will present the development methodologies of the Gigabit Information-processing and Networking Technology(GIANT) and the special features of configuration management system applied to GIANT project, and suggest some proposals about its utilization with respect to systems engineering point of view.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.2 no.4
• /
• pp.575-581
• /
• 1998

In order to accommodate current accelerated growth in customers and traffic. Internet has faced the demand to scale its network dimension both in size and bandwidth, and new service provisioning. One way to solve this problem is to forward If packets based on ATM switching technology. This paper briefly explained technical tasks to apply this If switching technique in ATM networks for building Internet backbone, and presented the directions to approach these tasks. Those tasks are scalability, ATM VC setup and mapping between VC and IP packet flow, traffic management and traffic engineering, multicast, and finally ATM switch architecture to provide multiservice.

• Journal of Korea Multimedia Society
• /
• v.19 no.5
• /
• pp.924-931
• /
• 2016

In this paper, Various network adaptive MAC scheduling technique is proposed to effectively overcome limits of narrow bandwidth and low transmission speed in underwater. UPFC(Underwater Packet Flow Control) is a technique to reduce both the number of transmission and transmission time using three types (Normal, Blocked, Parallel) of data transmission. In this technique, the load information, in which a transmission node have, is transmitted to destination node using marginal bit in reserved header. Then the transmitted information is referred to determine weighting factor. According to the weighting factor, scheduling is dynamically changed adaptively. The performance of UPFC is analyzed and flow control technique which can be applied to Cluster Based Network and Ad Hoc network as well.

• Journal of Korea Multimedia Society
• /
• v.19 no.5
• /
• pp.910-917
• /
• 2016

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to the sink node to pass collected data. However, the communication distance of the sensor nodes at low cost and at low power is not long, it requires a data transfer through the multi-hop to transmit data to the sink node. In the existing cluster-based sensor network studies, cluster process and route selection process are performed separately in order to configure the routing path to the sink node. In this paper, in order to use the energy of the sensor nodes that have limited resources efficiently, a cluster-based multi-hop routing protocol which merges the clustering process and routing process is proposed. And the proposed method complements the problem of uneven cluster creation that may occur in probabilistic cluster methods and increases the energy efficiency of whole sensor nodes.

• Journal of Advanced Navigation Technology
• /
• v.12 no.5
• /
• pp.444-450
• /
• 2008

With the advancement of the mobile device and arrival of the integrated wired/wireless environments, the damand for services accessible by mobile devices is rapidly increasing. However, unlike existing wired networks, communication in wireless networks has many weaknesses. Therefore, research and development into an appropriate security technology has reached a critical stage, as combined wired/wireless environments emerge. Therefor, in this paper, we propose that device authentication technology in AAA (Authentication, Authorization, Accounting) mechanism of Mobile environment for secure service offer.

• Journal of Korean Library and Information Science Society
• /
• v.34 no.4
• /
• pp.1-20
• /
• 2003

Through analyzing papers on digital libraries and the contexts of usage of the term, ‘digital library’, this study investigates that the professional discourses about digital libraries regard them digital technologies. But digital libraries need to be recognized as socio-technical networks which are constructed by social interaction between heterogeneous elements. The study suggested that Social Informatics and a STIN(Socio-Technical Interaction Network) model should be applied to understand and analyze digital libraries as socio-technical networks.