• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.101-110
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• 2009

The 6LoWPAN(IPv6 Low-power Wireless Personal Area Network) performs IPv6 header compression, TCP/UDP/IGMP header compression, packet fragmentation and re-assemble to transmit IPv6 packet over IEEE 802,15.4 MAC/PHY. However, from the point of view of security. It has the existing security threats issued by IP packet fragmenting and reassembling, and new security threats issued by 6LoWPAN packet fragmenting and reassembling would be introduced additionally. If fragmented packets are retransmitted by replay attacks frequently, sensor nodes will be confronted with the communication disruption. This paper analysis security threats introduced by 6LoWPAN fragmenting and reassembling, and proposes a re-transmission mechanism that could minimize re-transmission to be issued by replay attacks. Re-transmission procedure and fragmented packet structure based on the 6LoWPAN standard(RFC4944) are designed. We estimate also re-transmission delay of the proposed mechanism. The mechanism utilizes timestamp, nonce, and checksum to protect replay attacks. It could minimize reassemble buffer overflow, waste of computing resource, node rebooting etc., by removing packet fragmentation and reassemble unnecessary.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.06a
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• pp.932-935
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• 1998

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.389-394
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• 2017

In a conventional ship structure, stiffeners with an asymmetric section, such as inverted angles, are used widely despite the disadvantage of strength compared to the stiffeners with a symmetric section, such as a built-up T. On the other hand, T-type built-up members are attracting more attention than L-type inverted angles due to the increased size of ships. The purpose of this study was to develop an optimal design program for a built-up T, and apply an evolution strategy as an optimization technique. In the optimization process, the gross thickness concept was adopted for the design variables and objective function, and the constraints are set up based on HCSR (Harmonized Common Structural Rules). Using the developed program in this study, the optimal stiffener design was carried out for 300K VLCC and 158K COT of which the orders were obtained lately. The optimal results revealed the weight reduction effect of 144 tons and 60 tons, respectively.

• 한국문화재보존과학회:학술대회논문집
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• 2004.03a
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• pp.71-77
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• 2004

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.71-71
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• 2004

KSLV-I 추진기관 기체공급계는 상부의 산화제 탱크로부터 나온 산화제 주배관이 하부의 연료탱크를 관통하여 엔진공급계로 이어지도록 구성되어 있다. 연료탱크에는 산화제 배관의 관통을 위한 tunnel이 구성되어 있으며 배관과 tunnel은 일정한 간격을 유지하게 된다. 배관과 연료탱크 사이의 열전달을 줄이기 위하여 산화제 배관에 단열재를 적용할 수 있으나, 이 경우 배관의 운송, 조립시에 handling이 힘들게 되고, 특히 발사체에 조립된 후에 발생하는 단열재의 파손 및 성능감소에 대한 유지보수가 불가능하다. (중략)

• Journal of KIISE:Software and Applications
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• v.34 no.12
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• pp.1011-1020
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• 2007

It is difficult to assemble independently developed software components because of discrepancies between their interfaces. In order to resolve such problem, we propose a new component model, Active Binding Technology, in which each component has its own independently-defined interface for service request that is revealed in its metadata, instead of passively following the interface of a service-providing component. This model Includes the use of the glue component, an interface mediating place, whose template code is automatically generated by reading in the metadata of the components to be combined. We also propose a runtime framework that holds the pool of component instances, completes the assembly of components in the manner of dependency injection, and performs middleware services and real-time system monitoring through glue components. In order to test the practical value of Active Binding Technology, we have made a tool, which supports the development and assembly of Active Binding components.

• Journal of the Korean Geosynthetics Society
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• v.12 no.1
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• pp.11-19
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• 2013

Coarse-grained soils are typical engineering materials commonly used in many civil engineering applications such as structural fills, subgrade and drainage fills for dam, railway and bridge. Various researches have been performed with related to constitutive laws for numerical analysis of such structures. This paper presents a parametric study for a constitutive model for coarse grained materials. The model is a kind of the bounding surface models based on critical state theory. A distinct feature of the model is to capture the response of coarse-grained materials with different void ratios and confining pressures using a single set of model parameters. The model behavior is defined with a set of elastic parameters, critical state parameters, and model-specific parameters. The parametric study was performed for the model-specific parameters. The result of parametric study shows that the model is capable to capture stress-dilatancy behavior and kinematic-hardening under non-associative plastic flow.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.36-43
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• 2018

A great deal of difficulty is encountered in the thermo-mechanical analyses of nozzle assemblies for solid propellant rocket motors. The main issue in this paper is the modeling of the boundary conditions and the connections between the various components-gaps, relative movements of the components, contacts, friction, etc. This paper evaluates the complex phenomena of nozzle assemblies during burning time with co-simulations that include fluid, thermal surface reaction/ablation, and structural analysis. The validity of this approach is verified via comparison of analysis results with measured strains.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.207-209
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• 2010

오늘날 네트워크 통신은 다양한 해킹방법들로부터 데이터를 보호하기 위하여 다양한 암호화 알고리즘을 사용하여 통신하고 있다. 이렇게 사용되는 암호화 알고리즘에서 키가 누출되어 해킹되었을 경우 데이터에 대한 정보누출 및 수정, 삭제 등의 데이터 가공을 당하게 된다. 본 논문에서는 이러한 문제를 보완하기 위하여 본래의 데이터를 섞고, 재조립하는 조립알고리즘을 제안한다.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.36-46
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• 1999

This paper proposes a redesign procedure for assemblability and automatic assembly of an automobile heater blower motor. According to the procedure, redesign alternatives are generated, then the alternatives are evaluated by a weighted objectives method to select one optimal redesign alternative. First, the redesign objectives are identified and the assemblability of the current motor is evaluated to decide redesign rules. Finally, the redesign variants and alternatives are generated using the redesign criteria. This information is then evaluated to select an optimal alternative, determined by weighted evaluation criteria which is established in advance.