• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.571-580
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• 2005

In fast long-distance networks, TCP's congestion control algorithm has the problem of utilizing bandwidth effectively. Several window-based congestion control protocols for high-speed and large delay networks have been proposed to solve this problem. These protocols deliberate mainly three properties : scalability, TCP-friendliness, and RTT-fairness. These protocols, however, cannot satisfy above three properties at the same time because of the trade-off among them This paper presents a new window-based congestion control algorithm, called EM (Exponential Increase/ Multiplicative Decrease), that simultaneously supports all four properties including fast convergence, which is another important constraint for fast long-distance networks; it can support scalability by increasing congestion window exponentially proportional to the time elapsed since a packet loss; it can support RTT-fairness and TCP-friendliness by considering RTT in its response function; it can support last fair-share convergence by increasing congestion window inversely proportional to the congestion window just before packet loss. We evaluate the performance of EIMD and other algorithms by extensive computer simulations.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.75-81
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• 2014

This study is analyzed using the Shanghai stock market and Shenzhen stock market data in order to analyze the usefulness of accounting information to appear from the introduction of international accounting standards in China. Summarized the relevant previous researches for objective study approach, studied the hypothesis based on the empirical analysis and set a hypothesis as adjusting the stuffs to fix in this research model. In this study, Analyzed the hypothesis to input of detailed variables for analyzing the value relevance between periods before fair value and after fair value. Also, in this hypothesis study, analyzed and estimated to affect the quality of information the acceptant period when compare with acceptant periods and before periods of fair value. These results suggested that impact the net asset value per share and earnings per share of the company because the value of the relationship had statistically significant at the level of relevance. Therefore, in the future studies about fair value assessment, will be expected that usefulness of the enterprise value evaluation method enable to discuss it such as critical sucess factors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.1035-1048
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• 2023

The IEEE 802.11 WLAN adopts a random backoff algorithm for its collision avoidance mechanism, and it is well known that the contention-based algorithm may suffer from performance degradation especially in congested networks. In this paper, we design an efficient backoff algorithm that utilizes a reinforcement learning method to determine optimal values of backoffs. The mobile nodes share a common contention window (CW) in our scheme, and using a Q-learning algorithm, they can avoid collisions by finding and implicitly reserving their optimal time slot(s). In addition, we introduce Frame Size Control (FSC) algorithm to minimize the possible degradation of aggregate throughput when the number of nodes exceeds the CW size. Our simulation shows that the proposed backoff algorithm with FSC method outperforms the 802.11 protocol regardless of the traffic conditions, and an analytical modeling proves that our mechanism has a unique operating point that is fair and stable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.2171-2185
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• 2014

From the perspectives of regulation and convergence, several debates on the industrial definition of smart TV service in the Korean broadcasting and communications market are currently in progress. The most heated controversy mainly depends on whether smart TV is controlled under broadcasting regulations or under communications regulations. This Korean- specific problem is summarized in regulation fairness or asymmetric regulations between smart TV and IPTV operators. Although both operators utilize very similar technology and share the same business model, the regulations for only smart TV operators are unfettered. This would be an intrinsic cause that prohibits fair competition in the new converging market. Currently we confront the matter of asymmetric regulations between smart TV and others including IPTV or ISP. The purpose of this study, thus, is to provide the strategic, regulatory guidance and theoretical definitions on smart TV service, as one of converging services, based on a qualitative approach through subjectivity methodology. The study identifies three issues net neutrality, regulation fairness and new media and new market and proposes desirable promotion plans regarding those issues. The study draws lessons learned through a Korean smart TV case and provides directions to strategic-policy studies for future emergent converging services.