• Journal of Korean Society of Steel Construction
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• 제23권4호
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• pp.455-464
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• 2011

In this study, the buckling analysis of the vertically curved stiffened web plate was conducted through finite-element analysis, using an eight- and nine-node flat shell element with a substitute shear strain field. To investigate the buckling behavior of the vertically curved web plate with a longitudinal or vertical stiffener under in-plane moment loading, parametric studies were conducted for the variation of the width (b) and ratio of the bending stiffness of the stiffener to that of the plate (${\gamma}=EI/bD$). The static behavior of the vertically curved web plate without a stiffener was also investigated, and then the buckling abilities of the longitudinal and vertical stiffeners were compared under moment loading.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.277-280
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• 2009

Mobile Ad-hoc Network(MANET) could provide the reliable monitoring and control of a variety of environments for remote place. Mobility of MANET would require the topology change frequently compared with a static network. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. In this paper, we propose a new method that the CACH(Context-aware Clustering Hierarchy) algorithm, a hybrid and clustering-based protocol that could analyze the link cost from a source node to a destination node. The proposed analysis could help in defining the optimum depth of hierarchy architecture CACH utilize. The proposed CACH could use localized condition to enable adaptation and robustness for dynamic network topology protocol and this provide that our hierarchy to be resilient.

• Journal of the Korean Society for Precision Engineering
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• 제29권10호
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• pp.1056-1061
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• 2012

FEM analysis is essential to shorten the development time and reduce the cost for developing high-performance machine tools. Mount joint parts play important role to ensure static and dynamic stability of machine tools. This paper suggests a computational modeling of mount joint part of machine tools. MATRIX27 element of ANSYS is adopted to model mount joint parts. MATRIX27 allows the definition of stiffness and damping matrices in matrix form. The matrix is assumed to relate two nodes, each with six degrees of freedom per node. Stiffness and damping values of commercial mount products are measured to build a database for FEM analysis. Jack mounts with rubber pad are exemplified in this paper. The database extracted from the experiments is also used to estimate of stiffness and damping of untested mounts. FEM analysis of machine tools system with the suggested mount computational model is performed. Static and dynamic results prove the feasibility of the suggested mount model.

• Journal of Information Processing Systems
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• 제16권2호
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• pp.261-276
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• 2020

Digital contents services are one of the topics that have been intensively studied in the media industry, where various semantic and ontology techniques are applied. However, query execution for ontology data is still inefficient, lack of sufficient extensible definitions for node relationships, and there is no specific semantic method fit for media data representation. In order to make the machine understand digital contents (DCs) data well, we analyze DCs data, including static data and dynamic data, and use ontology to specify and classify objects and the events of the particular objects. Then the formal representation method is proposed which not only redefines DCs data based on the technology of OWL/RDF, but is also combined with media segmentation methods. At the same time, to speed up the access mechanism of DCs data stored under the persistent database, an ontology-based DCs query solution is proposed, which uses the specified distance vector associated to a surveillance of semantic label (annotation) to detect and track a moving or static object.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제9권3호
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• pp.9-17
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• 2009

A Mobile Ad hoc network(MANET) is a network consisting of a set of wireless mobile nodes, which communicate with each other without centralized control or established infrastructure. In this paper, to obtain a better understanding of AODV(Ad hoc On-Demand Distance Vector Routing Protocol)and OLSR(Optimized Link State Routing Protocol) routing protocols, different performances are simulated and analyzed using OPNET modeler 14.5 with the various performance metrics, such as packet delivery ratio, end-to-end delay and routing overhead. As a conclusion, in static analysis, the routing overhead of OLSR is affected by the number of nodes, but not data traffic. In AODV case, it is affected by both data traffic and number of nodes. In mobility analysis, routing overhead is not greatly affected by mobility speed in AODV and OLSR, and the PDR(Packet Delivery Ration) of OLSR is decreased as the node speed increased, while AODV is not changed. AS to delay, AODV is always higher than OLSR in both static and nobility cases.

• Journal of the Korea Institute of Military Science and Technology
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• 제15권6호
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• pp.770-778
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• 2012

In this paper, we propose a multi-path construction scheme to improve the survivability of a multicast session in military hybrid networks. A military hybrid network consists of a static backbone network and multiple mobile stub networks where some nodes are frequently susceptible to be disconnected due to link failure and node mobility. To improve the survivability of multicast sessions, we propose a construction scheme of ${\kappa}$ redundant multi-paths to each receiver. In order to take account of different characteristics of static and mobile networks, we propose quite different multi-path setup approaches for the backbone and stub networks, respectively, and combine them at the boundary point called gateway. We prove that our proposed scheme ensures that each receiver of a multicast session has ${\kappa}$ redundant paths to the common source. Through simulations, we evaluate the performance of the proposed schemes from three aspects : network survivability, recovery cost, and end-to-end delay.

• Journal of IKEEE
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• 제27권3호
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• pp.258-264
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• 2023

This paper proposes an LDO regulator with a built-in ESD (Electro Static Discharge) protection circuit to effectively operate and prevent destruction of the LDO (Low Drop Out) regulator according to the load current. The proposed LDO regulator can more effectively adjust the gate node voltage of the pass transistor according to the output voltage of the LDO regulator by using an additional feedback current circuit structure. In addition, it is expected to have high reliability for the ESD situation by embedding a new structure that increases the holding voltage by about 2V by reducing the current gain on the SCR loop by adding a P+ bridge to the existing ESD protection device.

• Journal of the Korean Magnetics Society
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• 제21권6호
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• pp.219-224
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• 2011

The motion features of sanals inside of the primo vascular system (PVS), that is so-called the Kyungrak system, are investigated under a low static magnetic field by using the anatomy technology and optical microscope. The sanals with a size of about 1 selected and separated from the primo vessel and node of the real PVS inside of the surface of the internal organs are observed from rabbits' abdominal wall and dipped with PBS liquid inside of petri dish. The sanal's moving velocity along the direction of magnetic field (xdirection) and perpendicular to the direction of magnetic field (y-direction) under the low magnetic field of 0 Oe, 20 Oe, 40 Oe, 60 Oe, and 80 Oe, respectively, is observed below a internal temperature of $38^{\circ}C$. Ten sanals' moving velocities versus magnetic field are shown two differently dominant tendencies with an average velocity of 0.9 pixel/s and a random velocity according to the x-direction and y-direction, respectively. This experimental results imply that the rotating motion of sanal with nuclei DNA composed of many inorganic magnetic materials of Mn and Co is monotonically weakened by the increase of applied magnetic field.

• Proceeding of KASS Symposium
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.95-100
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• 2008

A 4-node assumed strain finite element based on higher order shear deformation theory is developed to investigate the behaviours of symmetric and unsymmetric laminated composite plates. The present element is based on Reddy's higher order shear deformation theory so that it can consider the parabolic distribution of shear deformation through plate thickness direction. In particular, assumed strain method is adopted to alleviate the shear locking phenomena inherited plate elements based on higher order shear deformation theory. The present finite element has seven degrees of freedom per node and denoted as HSA4. Numerical examples are carried out for symmetric and unsymmetric laminated composite plate with various thickness values. Numerical results are compared with reference solutions produced by other higher order shear deformation theories.

• The Journal of the Korea institute of electronic communication sciences
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• 제11권10호
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• pp.941-948
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• 2016

In this paper, we efficiently simulated for collecting the data from the fixed sensor and mobile sensor of patients using the LEACH-Mobile method. The LEACH-Mobile method is the protocol to increase the mobility by adding the mobile node to the existed LEACH(:Low Energy Adaptive Clustering Hierarchy) protocol. It improves the mobility of The LEACH-Mobile in the LEACH, however it consumes more energy than the existed LEACH. There is reason why we use the LEACH-Mobile that the monitoring system is generally done by the CCTV and an periodic checkup by nurses. However the number of nurse is a few in the most of hospital. It can happen the accidents of the patients in out of the CCTV when the nurse can not see the monitoring system in the hospital. Therefore it is simulated to continuously gather the data of the position and sensors in the five situation of moving the patients in the hospital, it gets the result that the management of the mobile patients is more efficient.