• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.889-896
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• 2007

Advances in wireless networking, micro-fabrication and integration, and embedded microprocessors have enabled a new generation of massive-scale sensor networks. Because each sensor node is limited in size and capacity, it is very important to design a new simple and energy efficient protocol. Among conventional sensor networks' routing protocols, the directed diffusion scheme is widely blown because of its simplicity. This scheme, however, has a defect in that sending interest and exploratory data messages while setting connection paths consumes much energy because of its flooding scheme. Therefore, this paper proposes a new sensor network routing protocol, called sequenced directed diffusion with a threshold control, which compromises the conventional directed diffusion scheme's defect and offers an energy efficient routing idea. With a computer simulation, its performance is evaluated and compared to the conventional directed diffusion scheme. Numerical results show that the proposed scheme offers energy efficiency while routing packets, and resolves ill-balanced energy consumption among sensor nodes.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.225-230
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• 2012

When a car accident happened, the accident vehicle should broadcast a safe message to its neighbors in multi-hop. However, the pure flooding is difficult to protect a chain-reaction collision because of the frequent collision and the communication delay. To solve this problem, we proposes a back-off algorithm applied to the estimation of the neighbor node count using the t-distribution. And we proposes a MAC protocol preventing the communication delay by separating the neighbor's count collection channel and data channel. As a result, we show the frame reception success rate of our protocol improved more 10% than the previous protocol.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.3-6
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• 2005

In this paper, the real scenario of water situation (e.g. water management, water availability and flooding) in an irrigated rice cultivation area in Suphanburi Province, Central-West Thailand is discussed together with the NDVI time series data. The result shown is derived by our classifier named 'Peak Detector Algorithm (PDA)'. The method discriminated 5 classes in terms of irrigation activities and cropping intensities, namely, Non-irrigated, Poorly irrigated - 1 crop/year, Irrigated - 2 crops/year, Irrigated - 3 crops/year and Others (no cultivation happens in a year or other land covers). The overall accuracy of all classified results (1999-2001) is around $77\%$ against independent ground truth data (general activities or function of an area). In the classified results, spatial and temporal inconsistency appeared significantly in the Western and Southern areas of Suphanburi. The inconsistency resulted mainly by anomaly of rainfall pattern in 1999 and their temporal irrigation activity. The algorithm however, was proved that it could detect actual change of irrigation status in a year.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.2
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• pp.78-97
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• 2010

Route discovery in wireless mobile networks requires a considerable amount of resources due to the mobility of the hosts. Therefore, it would be wise to utilize the effort already invested in existing paths. This paper proposes an efficient way to reuse, whenever possible, existing paths when a new path is being established. In our proposed algorithm, called Route Reutilization Routing (RRR), the reusability is accomplished by the notion of the dynamic proactive zones (DPZ), through which nearby existing path information is disseminated. By utilizing the information stored in DPZs, RRR can achieve considerable savings over other on-demand routing algorithms that use flooding. The unique feature of the proposed algorithm is that DPZs are created and destroyed dynamically around the existing paths, whereas proactive zones are formed around the nodes throughout the network in other route finding algorithms. Even though using DPZs may not result in the shortest path between source and destination, simulation results show the considerable reduction in traffic needed to find a path and therefore increases the available bandwidth for data transmission.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4408-4425
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• 2023

Alarm flood due to abnormality propagation is the most difficult alarm overloading problem in nuclear power plants (NPPs). Root-cause analysis is suggested to help operators in understand emergency events and plant status. Multilevel Flow Modeling (MFM) has been extensively applied in alarm management by virtue of the capability of explaining causal dependencies among alarms. However, there has never been a technique that can identify the actual root cause for complex alarm situations. This paper presents an automated root-cause analysis system based on MFM. The causal reasoning algorithm is first applied to identify several possible root causes that can lead to massive alarms. A novel root-cause ranking algorithm can subsequently be used to isolate the most likely faults from the other root-cause candidates. The proposed method is validated on a pressurized water reactor (PWR) simulator at HAMMLAB. The results show that the actual root cause is accurately identified for every tested operating scenario. The automation of root-cause identification and ranking affords the opportunity of real-time alarm analysis. It is believed that the study can further improve the situation awareness of operators in the alarm flooding situation.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.215-219
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• 2004

A rapid development of the network brought increasing of many damage cases by hacker's attack. In recently many network and system resources are damaged by traffic flooding attacks. For this reason, the protection of network resources by analyzing traffic on the network is on the rise. In this paper, algorithm that improves the executing time and detection rate than traffic analysis method using SNMP is proposed and implemented.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.649-657
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• 2013

DTN flooding based routing protocol replicate the message copy to increase the delivery like hood that overloads the network resources. The probabilistic routing protocols reduce replication cost by forwarding the message to a node that holds high predictability value to meet its destination. However, the network traffic converges to high probable nodes and produce congestion that triggers the drop of previously stored messages. In this paper, we have proposed a routing protocol called as Connection frequency Buffer Aware Routing Protocol (CFBARP) that uses an adaptive method to maintain the information about the available buffer space at the receiver before message transmission. Furthermore, a frequency based method has been employed to determine the connection recurrence among nodes. The proposed strategy has performed well in terms of reducing message drop, message relay while increases the delivery probability.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.683-687
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• 2010

In this paper, we propose an anycast routing scheme for large-scale wireless mesh networks, which requires only one-hop local information with no flooding overhead. We develop an analytical model for anycast mesh networks based on an electrostatic theory. A finite difference method contributes to achieving gateway load balancing with constant control overheads. We verify the performance of the proposed scheme by simulations.

• Proceedings of the IEEK Conference
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• summer
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• pp.159-164
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• 2004

This paper aims towards designing and implementation of a new adaptive Peer to Peer (P2P) network that cluster itself on the basis of semantic proximity. We also developed an algorithm to classify the nodes to form the semantic groups and to direct the queries to appropriate groups without any human intervention. This is done using Bloom filters to summarise keywords of the documents shared by a peer. The queries are directed towards the appropriate clusters instead of flooding them. The proposed topology supports a system for maintaining a global, omnipresent trust value for each peer in an efficient manner both in terms of decision time and network load.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.173-178
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• 2013

To discover objects of interest in unstructured peer-to-peer networks, the peers rely on flooding query messages which create incredible network traffic. This article evaluates the performance of an unstructured Gnutella-like protocol over mobile ad-hoc networks and proposes modifications to improve its performance. This paper offers an enhanced mechanism for an unstructured Gnutella-like network with improved peer features to better meet the mobility requirement of ad-hoc networks. The proposed system introduces a novel caching optimization technique and enhanced ultrapeer selection scheme to make communication more efficient between peers and ultrapeers. The paper also describes an enhanced query mechanism for efficient searching by applying multiple walker random walks with a jump and replication technique. According to the simulation results, the proposed system yields better performance than Gnutella, XL-Gnutella, and random walk in terms of the query success rate, query response time, network load, and overhead.