• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.419-428
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• 2004

Due to the deployment problem of the IP Multicast service, the Application Layer Multicast (or Overlay Multicast) has appeared as an alter-native of the If Multicast. However, even though plenty of the Application Layer Multicast (ALM) Protocols were designed and their applications were developed according to the diverse requirements of each multicast service, researches on the ALM Protocols are focused on only a protocol design or an efficient multicast group management algorithm. And there is little effort to provide a unified guideline for development of the ALM Protocols and provide an environment for running multiple protocols simultaneously in a system. In this paper, we propose socket APIs to be a reference in developing new ALM Protocols which enables a system to support multiple protocols in a system with other ALM Protocols and which gives an environment to support efficient protocol management.

• Membrane Journal
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• v.25 no.5
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• pp.422-430
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• 2015

The present study announces that the pH value of seed coating solution makes a significant effect on the microstructure of silicalite-1 zeolite layer formed on ${\alpha}$-alumina support. Seed with an average diameter of 75 nm was dispersed in ethanol to prepare three kinds of seed coating solutions with different pH values, and dip-coated on the support. The pH value was controlled to be 2.2, 7.0, and 9.3, respectively. In the secondary growth process, pH 7 seed solution resulted an uniform, 3 to $4{\mu}m$ thick, completely covered, and 100 nm grained silicalite-1 zeolite separation layer. The uniformity and completeness were explained by a uniform, closely packed, multi-layered, and completely covered seed coating in the pH 7 condition. In the condition, ${\alpha}$-alumina support and seed are oppositely charged: support is positively charged (8.4 mV) and seed, negatively (-1.7 mV). The opposite charging induced a strong electrostatic attraction between seed and support, which made the good seed coating state. On the other hand, pH 2.2 and pH 9.3 seed solutions resulted non-uniform, partially covered, and around $1{\mu}m$ grained zeolite separation layer, since seed and support are the same sign charged in the conditions. The same sign charging induced a strong electrostatic repulsion between seed and support which caused a low coverage of seed. It could be concluded that the pH value of seed coating solution is a key parameter to determine the microstructure of silicalite-1 zeolite separation layer.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.360-360
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• 1998

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.690-696
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• 2006

Thickness of damping layer in sandwich plate needs to be optimized in order to make modal loss factor of the sandwich plate maximum. Since previous studies were interested in noise reductions over high frequency range, the modal properties were derived based on simply supported boundaries. This conventional formula is approximately applicable to other boundary conditions over high frequency range only. The purpose of this study is to propose a method to determine optimum damping layer thickness of sandwich plate for maximum modal damping in low frequency range when the boundary condition is not a simple support. The conventional RKU equation based on simply supported boundary is modified to reflect other boundary conditions and the modified RKU equation is subsequently applied to determine the optimum damping layer thickness for arbitrary conditions. In order to reflect frequency-dependent characteristics of elastic modulus of the damping layer, an iteration method is proposed in determining the modal properties. Test results on sandwich plates for optimum damping layer thickness are compared with predictions by the proposed method and conventional method.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.4 s.304
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• pp.59-68
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• 2005

In this paper, we design a PCI Express controller for future communication system The controller supports the full functionality of Transaction Layer and Data Link Layer of PCI Express. The designed controller has the proposed transmitter buffer architecture to obey Replay mechanism. This scheme merges the transmitting buffer and the replay buffer. The proposed buffer has the higher data transfer efficiency than the conventional buffer architecture because it can dynamically adjust size of a replay buffer space. We also design transmitter of Transmitter Transaction Layer to effectively support the proposed buffer, The receiver device of PCI Express must possess the buffer for three types of transaction to support Flow Control. And it must report the amount of the buffer space regularly to the Port at the opposite end of the link. We propose the simple receiver buffer scheme using only one buffer to easily support Flow Control. And the designed controller is verified under proposed test bench

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1197-1202
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• 2017

Security services that support electric energy service gateway require relatively high reliability. In particular, the application services that accompany communications and data are run organically. Each of the security services should support a secure service platform that supports a secure, scalable life cycle for existing services which should be extends security layer of Universal Middleware. In this convergence platform, it is the study of security transfer modular services that allow independent life cycle management of systems through Universal middleware. First, It is modular in terms of energy consumption service and data, enabling real-time operation, communications, remote management and applications. Second, the life cycle of the secure module to support start, stop and updating of the security module by applying the security policy module layer concept. It is modular system enabling to design of dyanmic models in the smart grid, the service was intended to be standardized and applied to the security service platform.

• Membrane Journal
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• v.17 no.1
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• pp.14-22
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• 2007

This is the research about the concentration of trace Magnolia flavor components in water by pervaporation. We have investigated the change of selectivity depending on support membrane structure and active layer thickness using prepared PVDF/PDMS composite membrane. Through the pure water flux test for PVDF support membrane, we could indirectly confirm that as the coagulation temperature decreases and the polymer concentration increases, the surface porosity and pore diameter decreases. Appling these results to transport mechanism, we could explain the effect of support membrane structure for the composite membrane. The selectivity increases as the thickness of PDMS active layer increases. We could know that there is a limitation to describe the transport on the active layer by Fick's law through these results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.291-293
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• 2017

Security services that support electric energy service gateway require relatively high reliability. In particular, the application services that accompany communications and data are run organically. Each of the security services should support a secure service platform that supports a secure, scalable life cycle for existing services which should be extends security layer of Universal Middleware such as OSGi platform. In this convergence platform, it is the study of security transfer modular services that allow independent life cycle management of systems through Universal middleware. First, It is modular in terms of energy consumption service and data, enabling real-time operation, communications, remote management and applications. Second, the life cycle of the secure module to support the life cycle of secure, delete, start and updating of the security module by applying the security policy module layer concept. It is modular in terms of power generation and accountability, enabling us to distinguish between reliability and accountability in a large volume of data models in the smart grid, the service was intended to be standardized and applied to the security service platform.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.837-840
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• 1999

In this paper, we design and verify the hardware circuit that performs PLCP(Physical Layer Convergence Protocol) protocol functions of physical layer in IEEE 802.11 frequency hopping WLAN(Wireless Local Area Network). Altera MAX＋PLUS I $I^{〔1〕}$ is used as a design tool. The designed circuit consists of control register module to interface with upper layer, FIFO module to transmit/receive data with upper layer, TX function module, and RX function module. It is verified that the developed circuit conforms well to the IEEE 802.11 standard specification and can support both 1Mbps and 2 Mbps transmission rate by simulation. The developed circuits can be utilized for the implementation of protocol processor in wireless LAN areas.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.268-272
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• 2015

Clear thermoplastic retainers have been widely used in daily orthodontics; however, they have inherent limitations associated with thermoplastic polymer materials such as dimensional instability, low strength, and poor wear resistance. To solve these problems, we developed a new type of clear orthodontic retainer that incorporates multi-layer hybrid materials. It consists of three layers; an outer polyethylenterephthalate glycol modified (PETG) hard-type polymer, a middle thermoplastic polyurethane (TPU) soft-type polymer, and an inner reinforced resin core. The resin core improves wear resistance and mechanical strength, which prevent unwanted distortion of the bucco-palatal wall of the retainer. The TPU layer absorbs impact and the PETG layer has good formability, optical qualities, fatigue resistance, and dimensional stability, which contributes to increased support from the mandibular dentition, and helps maintain the archform. This new type of vacuum-formed retainer showed improved mechanical strength and rate of water absorption.