• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3880-3899
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• 2019

Distributive desynchronization algorithms based on pulse-coupled oscillator (PCO) models have been proposed for achieving collision-free wireless transmissions. These algorithms do not depend on a global clock or infrastructure overheads. Moreover, they gradually converge to fair time-division multiple access (TDMA) scheduling by broadcasting a periodic pulse signal (called a 'firing') and adjusting the next firing time based on firings from other nodes. The time required to achieve constant spacing between phase neighbors is estimated in a closed form or via stochastic modeling. However, because these algorithms cannot guarantee the completion of desynchronization in a short and bounded timeframe, they are not practical. Motivated by the limitations of these methods, we propose a practical solution called PD-DESYNC that provides a short and deterministic convergence time using a flag firing to indicate the beginning of a cycle. We demonstrate that the proposed method guarantees the completion of desynchronization within three cycles, regardless of the number of nodes. Through extensive simulations and experiments, we confirm that PD-DESYNC not only outperforms other algorithms in terms of convergence time but also is a practical solution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3821-3841
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• 2019

Cloud radio access networks (C-RANs) have been regarded in recent times as a promising concept in future 5G technologies where all DSP processors are moved into a central base band unit (BBU) pool in the cloud, and distributed remote radio heads (RRHs) compress and forward received radio signals from mobile users to the BBUs through radio links. In such dynamic environment, automatic decision-making approaches, such as artificial intelligence based deep reinforcement learning (DRL), become imperative in designing new solutions. In this paper, we propose a generic framework of autonomous cell activation and customized physical resource allocation schemes for energy consumption and QoS optimization in wireless networks. We formulate the problem as fractional power control with bandwidth adaptation and full power control and bandwidth allocation models and set up a Q-learning model to satisfy the QoS requirements of users and to achieve low energy consumption with the minimum number of active RRHs under varying traffic demand and network densities. Extensive simulations are conducted to show the effectiveness of our proposed solution compared to existing schemes.

• The Research Journal of the Costume Culture
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• v.9 no.1
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• pp.100-110
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• 2001

The purpose of this study is to identify Internet usage for the implementation of Quick Response Supply Chain Management across Business-to-Business Electronic Commerce in textile and apparel industry. This paper involves theoretical studies, which developed 3 steps to analyze the relationship of B-to-B EC, SCM, and QR, and provides broader awareness of new trend in the textile and apparel industry. SCM as one of B-to-B EC solutions introduced QR into the textile and apparel industry in 1985, and B-to-B EC is regarded as a means for achievement of QR with the widespread adoption of Internet technologies by businesses over the last four years. Finally, the Internet enables textile and apparel firms to access international networks of suppliers, distributors, and customers, so Internet-based B-to-B EC, SCM, and QR with Internet/EDI and XML/EDI are expected to become a central part in propelling fashion business into new directions.

• The Journal of Information Systems
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• v.15 no.4
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• pp.189-209
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• 2006

The progress of mobile internet technologies has changed user access to information. The mobile internet allows to obtain contents and services from wireless networks via mobile devices. The purpose of this study is th find out important factors that influence on the customer purchase intention by mobile internet environment. Base on TAM(Technology Acceptance Model) and the latest literature, a comprehensive set of constructs and hypotheses were compiled with a methodology for testing them. We suggested five factors that effect purchase intention in mobile internet environment: Enjoyment Ease of use, Usefulness, Mobility, Trust To validate the research model, we collected data from cellular phone user using an online survey. The results of this study are as follows. First enjoyment ease of un, usefulness, and mobility had positive effects on trust. Second, Usefulness, ease of use, and trust had positive effects on purchase intention to use mobile internet. Third, enjoyment and mobility did not have positive effects on purchase intention to use mobile internet. Based on these results, we suggest marketing strategies.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.9
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• pp.638-643
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• 2004

Middleware enables different networking devices and protocols to inter-operate in ubiquitous home network environments. The UPnP(Universal Plug and Play) middleware, which runs on a PC and is based on the IPv4 protocol, has attracted much interest in the field of home network research since it has versatility The UPnP, however, cannot be easily accessed via the public Internet since the UPnP devices that provide services and the Control Points that control the devices are configured with non-routable local private or Auto IP networks. The critical question is how to access UPnP network via the public Internet. The purpose of this paper is to deal with the non-routability problem in local private and Auto IP networks by improving the conventional Control Point used in UPnP middleware-based home networks. For this purpose, this paper proposes an improved Control Point for accessing and controlling the home network from remote sites via the public Internet, by adding a web server to the conventional Control Point. The improved Control Point is implemented in an embedded GNU/Linux system running on an ARM9 platform. Also this paper implements the security of the home network system based on the UPnP (Universal Plug and Play), adding VPN (Virtual Private Network) router that uses the IPsec to the home network system which is consisted of the ARM9 and the Embedded Linux.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.769-772
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• 2003

Middleware enables different networking devices and protocols to inter-operate in ubiquitous home network environments. The UPnP(Universal Plug and Play) middleware, which runs on a PC and is based on the IPv4 protocol, has attracted much interest in the field of home network research since it has versatility. The UPnP, however, cannot be easily accessed via the public Internet since the UPnP devices that provide services and the Control Points that control the devices are configured with non-routable local private or Auto IP networks. The critical question is how to access UPnP network via the public Internet. The purpose of this study is to deal with the non-routability problem in local private and Auto IP networks by improving the conventional Control Point used in UPnP middleware-based home networks. For this purpose, this paper proposes an improved Control Point for accessing and controlling the home network from remote sites via the public Internet, by adding a web server to the conventional Control Point. The improved Control Point is implemented in an embedded GNU/Linux system running on an ARM9 platform.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1002-1015
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• 2018

The advent of Internet of Things (IoT) and the evident inadequacy of Cloud networks concerning management of numerous end nodes have brought about a shift of paradigm giving birth to Fog computing. Fog computing is an extension of Cloud computing that extends Cloud resources at the edge of the network, closer to the user. Cloud computing has become one of the essential needs of people over the Internet but with the emerging concept of IoT, traditional Clouds seem inadequate. IoT entails extremely low latency and for that, the Cloud servers that are distant and unknown to the user appear to be unsuitable. With the help of Fog computing, the Fog devices installed would be closer to the user that will provide an immediate storage for the frequently needed data. This paper discusses data migration between different storage types especially between Cloud devices and then presents a mechanism to migrate data between Cloud and Fog Layer. We call this mechanism Adaptive Deadline-Aware Scheme (ADAS) for Data migration between Cloud and Fog. We will demonstrate that we can access and process latency sensitive "hot" data through the proposed ADAS more efficiently than with a traditional Cloud setup.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.45-51
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• 2010

The main issue in mobile cloud computing is how to support a seamless service to a mobile mode. Mobile IPv6 (MIPv6) is a mobility supporting protocol which is standardized by the Internet Engineering Task Force (IETF). Mobile IPv6 fast handovers (FMIPv6) is the extension of MIPv6 which is proposed to overcome shortcomings of MIPv6. Recently, fast handovers for Mobile IPv6 over IEEE 802.16e which is one of broadband wireless access systems has been proposed by the IETF. It was designed for supporting cross-layer fast handover. In this paper, we propose an enhanced cross-layering mobile IPv6 fast handover over IEEE 802.16e networks. In our scheme, a new access router generates a new address for the mobile node by using a layer 2 trigger. We utilize a layer 2 message which is sent from a new base station to the new access router in order to inform the new access router of information of the mobile node. A previous access router sends a binding update message to the mobile node's home agent when it acquires the new address of the mobile node. We evaluate the performance of the proposed scheme compared with the existing schemes in terms of the signaling cost and the handover latency. From the results, we observe that the proposed scheme can support fast handover effectively over IEEE 802.16e networks than existing schemes.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.1-14
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• 2011

This paper analyzes the fairness and efficiency of channel sharing when heterogeneous wireless networks that have different transmission power and/or coverage coexist with the contention-based channel access protocol. First, we show that the existing CSMA (carrier sensing multiple access) protocol, that is a prevailing contention-based mechanism, results in significant unfairness of channel access because of (1) the asymmetric capability of carrier sensing and (2) the blindness of binary exponential backoff and link adaptation mechanisms to the interference-driven transmission failures. Next, we derive the feasible region of carrier sensing thresholds that assures spatial reuse and fair channel sharing simultaneously. Moreover, we establish an analytical model for per-system throughput and investigate the effect of contention window size and transmission rate on the fairness and efficiency of channel sharing. Finally, we compare the performance of several approaches for fair channel sharing via simulations under various network configurations.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.109-114
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• 2004

Increasing popularity of WLAN and advancement of WPAN allow user to connect to the Internet easily today. The increasing of number of networking mobile device such as laptop and PDA requires computing devices to share high speed Internet line or work on networks in most cases. This has stimulated the demand of access point that supports multiple network interfaces. This paper describes the process of design, implementation and test of the wired/wireless integrated access point that supports multiple network interfaces such as wired LAN, wireless LAN, Bluetooth, and Broadband network. We designed and developed the hardware system and protocol software to integrate heterogeneous network. The system has shown compatibility with standard specification and good performance through testing with various network devices.