• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.47-59
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• 2009

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting latency may vary depending on the type of applications, thus requiring application-specific algorithm and protocol design paradigms which help us to maximize energy conservation and thus the network lifetime. In this paper, we propose a novel delay-adaptive sensor scheduling scheme for energy-saving data gathering which is based on a two phase clustering (TPC). The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to the application-dependent and time-varying delay requirements. The TPC requests sensors to construct two types of links: direct and relay links. The direct links are used for control and forwarding time critical sensed data. On the other hand, the relay links are used only for data forwarding based on the user delay constraints, thus allowing the sensors to opportunistically use the most energy-saving links and forming a multi-hop path. Simulation results demonstrate that cluster-based delay-adaptive data gathering strategy (CD-DGS) saves a significant amount of energy for dense sensor networks by adapting to the user delay constraints.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.753-758
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• 2011

According to the needs for equipment performance, reliability, and performance for impending time to guarantee its viability, various redundancy techniques have been used in many military systems. Typically, one of redundancy schemes to increase the viability of the system is to configure a network between two processes. However, when some failure or loss in a physical network occur, redundancy schemes may not operate well. In this paper, we present a protocol scheme of VMEbus master and slave of a shared memory region, interrupts, and a dedicated task communication. Specifically, we confirm the validity of the presented scheme through the direct implementation of the protocol and some experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.107-116
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• 2006

In this paper, we propose a Sensing Resolution-based Grouping(SRG) protocol for wireless sensor networks. SRG is intended for meeting the application's sensing objectives, where sensor nodes are densely deployed and have the determinate accuracy requirement. The primary contribution of this paper is active group header node selection and round-robin procedure, which increase the sensing accuracy and evenly distribute the node energy consumption. The second contribution is use of energy efficient intermediate node selection by considering group size and energy consumption. We present the design principle of SRG and provide simulation results.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.141-148
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• 2009

Wireless Sensor Networks (WSN) can be applied to various industry fields and environment analysis fields with the progress of various sensor technologies. Also WSN help automatically monitoring of sensor nodes installed at wide area. Especially, the tiny sensor nodes recently developed for the environment analysis require much more electronic power. The reasons are the measurable fields are departmentalized and the more detailed measuring fields are created by the development of various materials and applications. Furthermore, the sensor nodes operated by small batteries for the fields require low cost and low power consumption in wireless networks technology. The power efficiency is the most important factor for the WSN life time. Because the sensor nodes are installed at wide area and hard to recover. This paper proposes the WSN algorithm is applied sensor node that has low power consumption and efficiency measurement.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.247-255
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• 2011

Most existing clustering protocols have been aimed to provide balancing the residual energy of each node and maximizing life-time of wireless sensor networks. In this paper, we present the adaptive clustering strategy related to sink position for clustering protocols in wireless sensor networks. This protocol allows networks topology to be adaptive to the change of the sink position by using symmetrical clustering strategy that restricts the growth of clusters based on depth of the tree. In addition, it also guarantees each cluster the equal life-time, which may be extended compared with the existing clustering protocols. We evaluated the performance of our clustering scheme comparing to LEACH and EEUC, and observe that our protocol is observed to outperform existing protocols in terms of energy consumption and longevity of the network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1832-1840
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• 1999

This paper proposed a network to implement all optical bidirectional BLSR/4 WDM/SHR allowing restoration in the event of a failure. The proposed network can provide a high degree of transparency using all-optical components with no electric implementation and effective failure restoration due to BLSR/4 WDM/SHR architecture. This paper also presented a genetic simulation model for the survivability analysis of the proposed BLSR/4 WDM/SHR under failure scenarios, the restoration performance of the proposed network is analyzed in terms of performance parameters such as propagation time, processing time, optical switch time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8A
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• pp.679-687
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• 2005

A mobile ad-hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. It is necessary to use bandwidth effectively because MANET has limited bandwidth. In this paper, we propose SMGS (source based multiple gateway selection routing protocol). In SMGS, each node estimates its expected life time (ELT) and if its ELT is larger than that of current gateway it becomes a candidate node. When a source node establishes a path, in each grid the candidate node will take the route request and be a gateway node for the each source node. The node that is expected to stay the longest time in the grid is selected so that we can reduce frequent gateway handoff, packet loss, and handoff delay.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.707-716
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• 2009

Wireless Sensor Networks are consisted of sensor nodes that communicated with each other to transmit information. Because sensor nodes have physically many limits, wireless sensor networks are hard to adopt for traditional networks. Transmissions are consumed most energy of sensor nodes. That's why energy-efficient transmission techniques and QoS support techniques for different kind of data are most important in wireless sensor networks. The thesis proposes the agent based framework for energy distribution and QoS in wireless sensor networks. Agents have its own behavior policy by means of a gene, which is optimized by genetic operations. Agents behavior to distribute energy consumption over sensor nodes. Simulation results show that the enhanced framework extends the lifetime of sensor nodes. Successful transmission ratios of emergency data and non emergency data are increased by 27% and 14%, respectively. Also, the results demonstrate that Qos of networks are improved.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.79-86
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• 2009

In this paper, we propose a new clustering scheme that provides optimal data aggregation effect and reduces energy consumption of nodes by considering the density of nodes when forming clusters. Since the size of the cluster is determined to ensure optimal data aggregation rate, our scheme reduces transmission range and minimizes interference between clusters. Moreover, by clustering using locally adjacent nodes and aggregating data received from cluster members, we reduce energy consumption of nodes. Through simulation, we confirmed that energy consumption of the whole network is minimized and the sensor network life-time is extended. Moreover, we show that the proposed clustering scheme improves the performance of network compared to previous LEACH clustering scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.87-93
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• 2016

In this paper, we propose a RF energy harvesting based routing protocol in mobile ad-hoc wireless sensor networks. The main features and contributions of the proposed routing protocol are as follows. First, establishment of routing route based on both remaining energy of mobile sensor nodes and RF energy harvesting. Second, establishment of routing route by considering availability and stability of route based on energy of mobile sensor nodes to increase lifetime of networks and route. The performance evaluation of the proposed routing protocol using OPNET shows that the routing method considering both route availability and route stability based on RF energy harvesting can increase efficiently route lifetime.