• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1129-1140
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• 2017

Unidirectional data transmission system, which allows physical one way transmission, removes the backward link physically to prevent the intrusion from the outside through the network. However, the system is difficult to apply to the environment requiring either backward transmissions or bi-directional communications. In this paper, we proposed Limited Two-way communications system, called as LimTway, which only allows outbound TCP two-way communications. LimTway uses two one-way links(forward, backward). While the forward one-way link is staying to be activated so that an allowed outbound UDP traffic could be transmitted one-way always, the backward one-way link is activated while allowed outbound TCP sessions are established. In order to prevent the intrusion from the outside during the period, the software of LimTway is designed to allow only the transmissions of both outbound TCP two-way communication traffics and outbound UDP traffics.

• Journal of KIISE:Databases
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• v.36 no.2
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• pp.123-138
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• 2009

In recent years, the web services composition search has become an issue of great interest. The web services composition search is the process of integrating individual web services to yield desired behavior. Through the web services composition search, more sophisticated functionalities can be provided. Current solutions can be classified into three main classes: forward chaining approach, backward chaining approach and two-phase approach. However one-way chaining approaches, such as forward chaining approach and backward chaining approach have limitations of searching irrelevant web services. And two-phase approach has limitations of including redundant web services. In this paper, we propose an unredundant web services composition search based on the two-phase algorithm. The algorithm consists of a forward phase and a backward phase. In the forward phase, the candidate web services participating composition will be found efficiently by searching the Link Index. In the backward phase, unredundant web services compositions will be generated from candidate web services by using the Token Manager. The experimental results show that our proposed algorithm is more efficient than one-way chaining approaches. The experimental results also show that our algorithm can provide more solutions than previous two-phase approach and is comparable to previous one in execution time.