• Fire Science and Engineering
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• v.26 no.1
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• pp.113-119
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• 2012

In this research, in order to prevent spread of vertical flame from building exterior fire, A head was developed. The performance standards of Head development complied with NFPA 80A 7.7.4.3 (Recommended Practice for Protection of Buildings Exterior Fire Exposures) and the standards are applied to the discharge pressure was 0.05 MPa and the discharge flow rate was 60 l/min. The head was developed about applied to 0.05 MPa and 65 l/min through the process of the experiment of five times, it is processed from drencher head and used in domestic intended use and structure are quite different. An appropriate distances between the head and the head proved as the experimental results to within 3 m~5 m and it selectively applied to the design is being considered depending on the fire hazard strength.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.241-244
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• 2012

In mobile ad-hoc networks, it should be the most important issue to reduce the power consumption of communications, because the resource of a node is limited in these networks. In existing cluster-based routing protocols, cluster headers participate in almost all communication processes. Therefore the lifetime of the cluster header is shortened and it does not have the effective route. In the proposed cluster-based routing protocol, the cluster header transmits a control packet which gives the route information to member nodes. This makes that the cluster header decreases the number of participating in communications, and that node members do not have to communicate trough the cluster header. This results in extending the lifetime of the cluster header, and having the effective route, data transmission rate and improved stability of routes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.224-227
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• 2012

In the Cluster-Based Routing Protocol (CBRP), a cluster header in each cluster is selected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP selects a cluster header without considering the remaining energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be selected frequently. In this paper, we propose the advanced protocol which prolongs the lifetime of the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining energies of all of nodes are compared with one another, and the node with the highest energy is selected as the cluster header.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2358-2364
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• 2010

Recently, In the wireless sensor network, a study which guarantees integrity of not only data gathered from sensor node but also energy consumption of it is now going on. However, the existing study cannot guarantee data integrity and overhead of cluster head which merges data from sensor node. This paper proposes multi-path hash chain technique which guarantees integrity of merged data and reduces overhead of cluster head when cluster head merges with data transmitted from sensor node. The proposed technique forms multi-hash chain dividing main-path and assistance-path to guarantee data integrity of cluster head, when merges data. The assistance-path, which is used when main-path is not, supports integrity of sensor node while minimizing overhead of cluster head when sensor node is authenticate.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.167-176
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• 2009

Traditional cluster-based routing method is a representative method for increasing the energy efficiencies. In these cluster-based routing methods, the selected cluster head collect/aggregate the information and send the aggregated information to the base station. But they have to solve the unnecessary energy dissipation of frequent information exchange between the cluster head and whole member nodes in cluster. In this paper, we minimize the frequency of the information exchange for reducing the unnecessary transmit/receive frequencies as calculate the overlapped area or number of overlapped member nodes between the selected cluster head and previous cluster head in the setup phase. So, we propose the modified cluster selection protocol method that optimizes the energy dissipation in the setup phase and reuses the saved energy in the steady-state phase efficiently that prolongs the whole wireless sensor network lifetime by uniformly selecting the cluster head.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5865-5872
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• 2011

Multi-hop communication in clustering system is the technique that forms the cluster to aggregate the sensing data and transmit them to base station through midway cluster head. Cluster head around base station send more packet than that of far from base station. Because of this hot spot problem occurs and cluster head around base station increases energy consumption. In this paper, I propose a cluster group head selection using trajectory clustering technique(CHST). CHST select cluster head and group head using trajectory clustering technique and fitness function and it increases the energy efficiency. Hot spot problem can be solved by selection of cluster group with multi layer and balanced energy consumption using it's fitness function. I also show that proposed CHST is better than previous clustering method at the point of network energy efficiency.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.739-750
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• 2016

The most of virtual reality headset have the separated controllers while they put on the headset; so the users may feel the discomfort and burden for the operation. In this paper, a novel virtual reality headset system using the EOG (electro-oculogram) is proposed and it has a distinguished feature that the user does not need to control the virtual reality headset by the hands, but the displayed contents are controllable by the electrical activity of the user's brain. The proposed system consist of the mobile device, a virtual reality headset, and an EOG headset for data acquisition. The system is implemented by using the Unity3D engine for the signal processing and controller, and the concept is confirmed through the implementation that it is more interesting and easier to control the virtual reality headset.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.534-543
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• 2006

As the topology frequently varies, more cluster reconstructing is needed and also management overheads increase in the wireless ad hoc/sensor networks. In this paper, we propose a multi-hop clustering algorithm for wireless sensor network topology management using dynamic pre-clusterhead scheme to solve cluster reconstruction and load balancing problems. The proposed scheme uses weight map that is composed with power level and mobility, to choose pre-clusterhead and construct multi-hop cluster. A clusterhead has a weight map and threshold to hand over functions of clusterhead to pre-clusterhead. As a result of simulation, our algorithm can reduce overheads and provide more load balancing well. Moreover, our scheme can maintain the proper number of clusters and cluster members regardless of topology changes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.781-783
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• 2014

Mobile ad hoc network(MANET) consists of node that has mobility. MANET has increased overhead that caused by frequent topology changes. For reducing overhead, hierarchical network that communicates through cluster head node has been researched. When traffic is concentrated on cluster head node, cluster member node can't send message. To solve this problem, we proposed Step Parent algorithm. Proposed algorithm, cluster member node checks traffic of cluster head node using route path of other cluster head node in efficient coverage area. When cluster head node has increased traffic, cluster member node make a new route path by route path by routing path to another cluster head node. So cluster member node sends a message to destination node, we check improving delivery ratio.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.337-342
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• 2022

Although printing technology has recently been widely used in IT fields including displays and fuel cells, residual and thermal stress are generated by a manufacturing process of stacking the layers of the print head and result in the substrate deformation and nozzle plate crack, which may cause ink leaks or not be ejected onto a desired region. Therefore, in this paper, we propose a new design of thermal inkjet print head with a robust and reliable structure. Diverse types of inkjet print head such as a rib, pillar, support wall and individual feed hole are designed to reduce the deformation of the substrate and nozzle plate, and their feasibility is numerically investigated through FEA analysis. The numerical results show that the maximum stress and deformation of proposed print head dramatically drops to at least 40~50%, and it is confirmed that there is no nozzle plate cracks and ink leakage through the fabrication of pillar and support wall typed print head. Therefore, it is expected that the proposed head shape can be applied not only to ink ejection in the normal direction, but also to large-area printing technology.