Chan-Hyun Youn

Learn More
In this paper, the energy efficiency of multi-input single-output and orthogonal frequency division multiplexing (MISO-OFDM) communication systems with power and capacity constraints is investigated. By formulating the power allocation problem of MISO-OFDM communication systems, the minimum subchannel transmission power is analyzed with power and capacity(More)
In cloud computing, it remains a challenge to allocate virtualized resource with financial cost minimization and acceptable Quality of Service assurance. In general, the VM instance is allocated to cloud service users based on not actual job processing time but the fixed resource allocation time predetermined by cloud pricing policy in contrast to grid(More)
This paper provides the first analysis of the impact of spectrum conversion on the lightpath blocking performance in the CO-OFDM optical networks. Two analytical models for the cases of using and not using spectrum convertors are developed for an H-hop end-to-end lightpath and a network, respectively. Numerical results show that the use of spectrum(More)
Energy efficiency is always a concern in hosting servers. When any new development is added to a host server, the power consumption of the host server must be theoretically and empirically re-evaluated. Because of the ongoing development trends in computing systems at the hardware, software and middleware levels, deriving a direct mathematical model for(More)
In wireless Grid computing environment, end-to-end Quality of Service (QoS) could be very complex, and this highlights the increasing requirement for the management of QoS itself. Policy quorum-based management offers a more flexible, customizable management solution that allows controlled elements to be configured or scheduled on the fly, for a specific(More)
Picture archiving and communications system (PACS) is widely used in hospitals to bring high efficiency in a medical process. Recently, PACS is required to evolve into a more sophisticated system that can communicate with other medical systems. The existing PACS was designed to be used in a local area network (LAN) of a hospital and DICOM, the standard used(More)
As cloud computing and wireless body sensor network technologies become gradually developed, ubiquitous healthcare services prevent accidents instantly and effectively, as well as provides relevant information to reduce related processing time and cost. This study proposes a co-processing intermediary framework integrated cloud and wireless body sensor(More)