• Journal of KIISE:Databases
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• v.37 no.3
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• pp.165-170
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• 2010

This paper proposes an in-network join strategy SBJ(Semi & Bloom Join), an efficient join strategy for sensor networks, that minimizes communication cost. SBJ is a hybrid join strategy that can reduce energy consumption by using a bloom filter to reduce the size of data that needs to be sent or received in sensor network. The key to reducing the communication cost in SBJ is to eliminate data not involved in the join result in the early stages of join processing. Through simulation, the paper shows that compared to other join strategies in sensor network, SBJ join strategy is more efficient in reducing the communication cost resulting in a significant reduction in battery consumption.

• Informatization Policy
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• v.18 no.3
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• pp.88-107
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• 2011

This paper proposes a prepaid system promotion policy for the 3G(WCDMA) MVNO with regard to the newly included paragraphs 3, 4 and 5 of Article 32 (User Protection) and Article 38 (Provision of Wholesale Telecommunications Services) of the Telecommunication Business Act, which was revised on March 22, 2010. As of June 2011, there are only a few prepaid system subscribers to the mobile communications service due to various limitations, including prepay, interconnection, carrier selection, the MVNO policy, and number portability. However, overseas communications service regulatory agencies and service providers are increasingly presenting policies and strategies for mobile prepaid plans, in order to accommodate the various customer demands that are increasing the use of smart phones and data. This paper advances various proposals concerning promotion of the prepaid system by the 3G MVNO under the current Telecommunication Business Act, including separation of the prepaid data system and the mobile network; introduction of a monthly fixed-rate hybrid prepaid system, a top-up system and USIM system; introduction of mobile network carrier selection; differentiated retail discounts between prepaid and post-paid prices; revision of the retail discount policy for wholesale provision; increase in the number of mandatory service providers; and in-depth consideration of the introduction of a number portability policy for the prepaid and post-paid systems.