• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.333-343
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• 2006

MANET and P2P applications have a common nature that they don't have any fixed infrastructures that might maintain network topologies. With such common characteristics, a P2P application can be a killer application over MANET. Due to absence of reliable node which serves indexing services in MANET, fully distributed P2P applications are more suitable for MANET. By using DHT like Chord, we can save network bandwidth and avoid a point of failure of a directory server. However, since MANET allows nodes to depart from network freely, P2P file sharing applications using Chord lookup protocol should address how to recover the keys stored at the departed node. In this paper, we propose BU-Chord in order to detect and recover the departure of nodes by creating and storing backup file information in distributed manner. Our BU-Chord shows off better performance than existing Chord especially in case of high departure rate of nodes.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.291-301
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• 2018

Supply chain in service sector has been established on the premise that firms need to manage their process uncertainties to satisfy customers in an efficient manner. Information sharing and synchronization play key roles in minimize uncertainties from their involved supply chain. The duality of customers being inputs providers as well as consumers, differentiates service supply chains from manufacturing and is a challenging issue to traditional supply chain management. The service supply chain is a structured network which should be managed with supply chain theory and principles. Various key operations need to be carried out through a highly integrated and collaborated service supply chain and supporting information hub. The purpose of this paper is to present the issues and key components in the service supply chain, where the repetitive service is provided along the value chain, such as tourism, restaurant, mega-sized hospital supply chain.

• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.793-798
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• 2003

The P2P service is a technology that can share their information with each other who is able to be connected ith a relating program without passing by a server. Since all personal compiters that linked to the internet under the P2P service can opetate as server or a client, they can provide and share both their information and services through the direct connection. Currently, the P2P service is giving an equal privilege to all users for sharing their resources,.Under this situation, a lot of vulnerability against the various sttacks through the Unternet is possoble, more sophisticated security services are necessary. In this paper, We propose and access control schemae using SPKI(Simple Public Key Infrastructure). The scheme designates and access and acces control by providing the certificate to users who request a connection for resource sharing and limits the resource usage of information provider according to the access right that is given to their own rights.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.463-466
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• 2016

Sharing of product and process information with partners is a basic activity and key requirement which ensures success of distribution. ePedigree that encapsulates all of the event data from manufacturer to retail shop provides a flexible mechanism of storing and sharing traceable information to the partners of supply chain and credibility of shared information through digital signature based on Public Key Infrastructure (PKI). To generate the signature that can be authenticated through PKI, the partners of supply chain should pay for PKI certificates from Certificate Authority (CA). In case of agrifood cooperatives which consist of petty merchants or farmers, it is hard to pay for the PKI certificate for all members and is a big obstacle for the ePedigree to be applied to the supply chain. This paper proposes a private certification method of ePedigree for cooperatives. Cooperatives can apply the ePedigree using the proposed method to all the members at small cost and the proposed method can assure the credibility of information at the same level of the previous ePedigree.

• Geomechanics and Engineering
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• v.31 no.5
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• pp.477-488
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• 2022

Pile composite foundation (PCF) has been commonly applied in practice. Existing research has focused primarily on semi-infinite media having equal pile lengths with little attention given to the effects of inclined bedrock and dissimilar pile lengths. This investigation considers the effects of inclined bedrock on vertical loaded PCF with dissimilar pile lengths. The pile-soil system is decomposed into fictitious piles and extended soil. The Fredholm integral equation about the axial force along fictitious piles is then established based on the compatibility of axial strain between fictitious piles and extended soil. Then, an iterative procedure is induced to calculate the PCF characteristics with a rigid cap. The results agree well with two field load tests of a single pile and numerical simulation case. The settlement and load transfer behaviors of dissimilar 3-pile PCFs and the effects of inclined bedrock are analyzed, which shows that the embedded depth of the inclined bedrock significantly affects the pile-soil load sharing ratios, non-dimensional vertical stiffness N₀/wdE_s, and differential settlement for different length-diameter ratios of the pile l/d and pile-soil stiffness ratio k conditions. The differential settlement and pile-soil load sharing ratios are also influenced by the inclined angle of the bedrock for different k and l/d. The developed model helps better understand the PCF characteristics over inclined bedrock under vertical loading.

• Journal of Korea Multimedia Society
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• v.8 no.12
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• pp.1638-1648
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• 2005

The SEM approach to PKl offers several advantages, such as immediate revocation of users' signing ability without CRLs and compatibility with the standard RSA. However, it has a weakness against denial of service attack caused by breaking down or being compromised. G. Vanrenen et al. proposed a distributed SEM approach to overcome the weaknesses. However, it does not provide the desirable properties such as instant availability and immunity against denial of service attack, due to inadequate usage of threshold cryptography and proactive secret sharing. In this paper, we point out its structural contradictions and propose a modified version of distributed SEM approach.

• Korean Journal of Computational Design and Engineering
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• v.22 no.1
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• pp.28-36
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• 2017

Sharing of CAD data plays a key role in the PLM and a lightweight model is widely used for visualizing and sharing a large data. The lightweight model is mainly composed of triangular elements to minimize file size. There is no problem at all to visually confirm the shape based on these triangular elements but there is a limit to numerically calculate the exact position on the curve or surface. In this paper, a boundary curve generation method using triangular elements is proposed to increase the utilization of lightweight models. After matching connectivity of triangular elements, boundary element edges are extracted. Boundary curves are generated by connecting of these boundary element edges. This proposed method has been tested on several models to demonstrate the feasibility.

• IE interfaces
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• v.10 no.3
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• pp.23-31
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• 1997

Exchange of product model data becomes a key issue in the globalized enterprise environment. Sharing heterogeneous information resides in diverse information resources is not easy. To share automotive product information among different organizations, a reliable neutral information standard and communication methods are needed. World wide sharing of automotive product information can be implemented based on the STEP AP214, the standard for exchange of automotive product model through its whole life cycle. This paper suggests an automotive PDM implemented on the internet and based on the STEP AP214. Physical files containing design data can be shared on the internet using JAVA applets and VRML.

• KIEE International Transactions on Power Engineering
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• v.3A no.2
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• pp.100-108
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• 2003

This paper presents the design and performance results of a pair of 6-kA high-temperature superconducting (HTS)-copper current leads, in which, over a short length at the warm end (e.g.,77K) of each HTS section, comprised of paralleled Bi-2223/Ag-Au tapes, is operated in the current-sharing mode. Because of their reliance on vapor cooling, the leads are applicable only to liquid helium cooled superconducting magnets such as those used in high-energy Physics accelerators and fusion machines. The experimental measurements have demonstrated that key performance data of the new 6-kA HTS-Copper leads agree reasonably well with those expected from design.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.02a
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• pp.161-161
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• 1996

Recently, the role of the surface analysis on the development of advanced materials has become larger and larger as the surface compositions of these materials is the key of their performances. Especially three techniques, Auger electron spectroscopy, X- ray photoelectron spectroscopy and secondary ion mass spectroscopy are widely used in technology fields. However, because of the relatively short history of these techniques(thirty years or so), there has been no accumulation of data commonly available, physical parameters for analysis have not been established and there has been no standard data. With these background, the VAMAS projects which aims to standardize the manner in the field of these techniques has started in 1982 at Versailles Summit. Along the projects, we have conducted the international collaborating study on the sharing of spectral data. In 1994, the Science and Technology Agency of Japan began the project on computer network, on which our fruits from the study on spectral data sharing is boarded.(omitted)mitted)