• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.103-112
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• 2006

Priority-based network service has been widely adopted for the Internet traffic management in the context of IETF differentiated services, and computing optimal prices for such priority-based service is the key topic in many pricing literature. While the equilibrium analysis has been commonly used to this end, many have criticized the validity of the underlying assumption of equilibrium analysis that user utility functions are precisely known. In this paper, we propose a solution for bridging the gap between the existing theoretical work on optimal pricing and the unavailability of precise user utility information in real networks. In the proposed method, the service provider obtains more and more accurate estimates of user utility functions from the initial imprecise knowledge by iteratively changing the price of service levels and observing the users' decisions under the changed price. Our contribution is two-fold. First, we have developed a general principle for estimating the user utility functions. Second, we have developed a novel method for setting the prices that can optimize the extraction of the knowledge about user utility functions. The extensive simulation results demonstrate the effectiveness of our method.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.219-221
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• 2012

The concave utility in the Network Utility Maximization (NUM) problem is only suitable for elastic flows. In networks with multiclass traffic, the utility can be concave, linear, step or sigmoidal. Hence, the basic NUM becomes a nonconvex optimization problem. The current approach utilizes the standard dual-based decomposition method. It does not converge in case of scarce resource. In this paper, we propose an algorithm that always converges to a local optimal solution to the nonconvex NUM after solving a series of convex approximation problems. Our techniques can be applied to any log-concave utilities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.8
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• pp.1913-1925
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• 2012

In order to efficiently utilize limited radio resources, resource allocation schemes in OFDMA-based wireless networks have gained intensive attention recently. Instead of improving the throughput performance, the utility is adopted as the metric for resource allocation, which provides reasonable methods to build up the relationship between user experience and various quality-of-service (QoS) metrics. After formulating the optimization problem by using a weighted bipartite graph, a modified bipartite matching method is proposed to find a suboptimal solution for the resource allocation problem in OFDMA-based wireless systems with feasible computational complexity. Finally, simulation results are presented to validate the effectiveness of the proposed method.

• Proceedings of the IEEK Conference
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• summer
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• pp.294-301
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• 2004

This paper presents a combination of optimization concept and congestion control for multicast communications to bring best benefit for the network. For different types of Internet services, there will be different utility functions and so there will be different ways to choose on how to control the congestion, especially for real time multicast traffic. Our proposed algorithm OMCC brings the first implementation experiment of utility-based Multicast Congestion Control. Simulation results show that OMCC brings better network performances in multicast session throughput while it still keeps a certain fairness of unicast and multicast sessions, and thus, provides better benefit for all network participants.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.27-34
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• 2024

The direct and indirect damages caused by fires in underground utility tunnels have a great impact on society as a whole, so efforts are needed to prevent and manage them in advance. To this end, research is ongoing to prevent disasters such as fire flooding by applying digital twin technology to underground utility tunnels. A network is required to transmit the sensed signals from each sensor to the platform. In essence, it is necessary to analyze the application of wireless networks in the underground utility tunnel environments because the tunnel lacks the reception range of external wireless communication systems. Within the underground utility tunnels, electromagnetic interference caused by transmission and distribution cables, and diffuse reflection of signals from internal structures, obstacles, and metallic pipes such as water pipes can cause distortion or size reduction of wireless signals. To ensure real-time connectivity for remote surveillance and monitoring tasks through sensing, it is necessary to measure and analyze the wireless coverage in underground utility tunnels. Therefore, in order to build a wireless network environment in the underground utility tunnels. this study minimized the shaded area and measured the actual cavity environment so that there is no problem in connecting to the wireless environment inside the underground utility tunnels. We analyzed the data transmission rate, signal strength, and signal-to-noise ratio for each section of the terrain of the underground utility tunnels. The obtained results provide an appropriate wireless planning approach for installing wireless networks in underground utility tunnels.

• Asia pacific journal of information systems
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• v.32 no.1
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• pp.168-190
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• 2022

This review aims to synthesize social network theories by drawing on the importance of social network perspectives in understanding knowledge management with technology in organizations. I provide an overview of prior social network research with the following core ideas: the primacy of relations between organizational actors, the utility of actors' embeddedness in social fields, the social utility of network connections, and the structural patterning of social life. On top of that, I summarize critical social perspectives (the social capital theory, the structural hole theory, the embeddedness perspective, the social exchange theory, the organizational learning theory, and the innovation diffusion theory) to suggest potential research questions for future studies in social network research in the knowledge management discipline.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1A
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• pp.76-83
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• 2009

In this paper, we provide opportunistic scheduling schemes for elastic services in OFDMA systems with fairness constraints for each user. We adopt the network utility maximization framework in which a utility function is defined for each user to represent its level of satisfaction to the service. Since we consider elastic services whose degree of satisfaction depends on its average data rate, we define the utility function of each user as a function of its average data rate. In addition, for fair resource allocation among users, we define fairness requirements of each user by using utility functions. We first formulate an optimization problem for each fairness requirement that aim at maximizing network utility, which is defined as the sum of utilities of users. We then develop an opportunistic scheduling scheme for each fairness requirement by solving the problem using a dual approach and a stochastic sub-gradient algorithm.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.329-330
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• 2019

스마트 유틸리티 네트워크 (SUN)는 가정, 빌딩, 공장 등에서 사용하는 전기, 수도, 가스와 같은 유틸리티를 효과적으로 관리할 수 있는 통신 네트워크 기술이다. 본 논문은 IEEE 802.15.4g 표준에 기반하는 Wireless-SUN 네트워크를 이용하여 원격 검침과 음성 동보 시스템을 구현하는 방안을 제시한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1443-1448
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• 2015

Most of access control systems for underground utility tunnel work through wired network between central system and the automatic switch control unit. However, there are several issues regarding the absence of network infrastructure and an outdoor reader in a relatively unique environment. To solve these issues we propose an authenticated key based smart phone control system for secure access to the underground utility tunnel and this scheme is anticipated providing us with crucial information about a systemic entrance history and effective management procedures of utility tunnel. In addition, the proposed scheme enables to access to secured control system in smart phone based bluetooth network and it provides information about systemic control and history management for the switch controls through smart phone applications.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.349-352
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• 2004

In this paper, we propose a newly energy-efficient routing protocol, which is called Maximum Utility Routing(MUR), in mobile ad hoc networks (MANETs) so as to investigate the minimum energy and maximum lifetimes issues together. We present a utility-based framework so as to meet various incompatible constraints simultaneously and fairly. To explore this issue, we use the concepts and mathematics of microeconomics and game theory. Though simulation results, we show that our routing scheme has much better performance especially in terms of network efficiency, network lifetime, and average power consumption.