• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.279-286
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• 2010

Unbalanced traffic load offered to the nodes making up a path in the network guaranteeing quality-of-service has been known as a main cause deteriorating the capability of the path in admitting traffic flows. Several path load balancing methods have been developed to resolve this problem which used a feedback control scheme that adjusts the delay budget of a flow allocated to each node according to the conditions of available resource in the path. Because of no consideration about the probabilistic characteristics of the service quality, it is impossible for them to prevent in advance a bottleneck on the path which leads to a native restriction in the improvement of the capability being deteriorated. This paper proposes a preventive intra-path load balancing method applicable to the RSVP system which is based on the probabilistic characteristics of the quality-of-service of the offered load. The results of the simulation of the proposed method on a simple evaluation network showed that it provides the gain of 4~22% compared to the legacy one in terms of the number of admitted flows.

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.111-118
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• 2014

The Smart grid refers to the technology that enables efficient usage of electric power by collecting information concerning the power usage and power lines grafting information and communications technology to onto power grids. There are Zigbee, PLC or IEEE 802.11 WLAN MAC as a core technology of the Smart grid, but in this paper, the discussion is focused on the PLC. The PLC is the technology that carries out data communications using power lines and put into practical use in the field of lights or home appliances control recently but PLC-applied communications between electronic devices are rarely seen. For the reason that the PLC uses high-voltage power lines and has a disadvantage of experiencing higher data loss rate caused by the noises produced by going through transformers, the technology is yet to be used in many areas. Nevertheless, the PLC has been studied widely recently in respect that it's the low-cost communication solution for the Smart Metering [1]. Moreover, this technology is emerging as a novel data communication method and discussed as an important technology lately due to the developments of the Smart grid systems and Internet of things (IoT). Thus, in this paper, the results obtained from designing and performing implementation scenario for the PLC-based Smart grid home network system were compared and analyzed with that of IEEE 802.11 WLAN MAC (the foundation technology at Jeju Smart grid Test bed)-based Smart grid home network. Thus, in this paper, OPNET 14.5 PL8, OSI 7 layer, PLC router nodes and PLC nodes had been used for the designing and implementation simulations of both systems. Additionally, QoS was not considered in order to guarantee that all the traffics would not have the same processing priority.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Convergence Security Journal
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• v.13 no.6
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• pp.77-82
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• 2013

Looking at the recent value change of users and the usage pattern of network users, it is changing from simple web information, one-way information acquisition and data transmission to increase of usage of multimedia, increasing demand for security and customization, and increasing demands for free mobility. Due to this change of demand, the services which were provided individually, developed into a form which is merged, the network also seems to develop into the combined network from the individual network for individual service, and the communication network control technology which is the core technology is also rapidly developing.. This paper propose three path computation scheme that not only use the resources effectively but also to minimize the information transmissions between the multi-layers in a multi-domain environment. This paper also suggested that the optimum path choice be performed through diversification of the path selection using the information of various layers altogether in the multi-layer environment, compared with the established path selection method when the path was selected using the information of each layers.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4787-4793
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• 2014

Background: Many cancer patients experience poor pain control due to various factors, including misconceptions regarding the use of opioid analgesics. For management of cancer pain, interventions involving education of both patients and physicians have been attempted. Objectives: This review aimed to assess the current evidence of the benefits of education for the management of cancer pain. Methods: We searched the Medline, EMBASE, Cochrane library, and major Korean databases to identify relevant studies. We included most study designs, but excluded case series. The primary outcomes were pain intensity and quality of life (QoL). Two reviewers assessed the risk of bias using the Cochrane's tool for RCT and Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for non-randomized studies, independently. Results: After extensive searches, 3,324 publications were screened, and 32 studies were selected. The education interventions used in the included studies included a wide variety of education methods, but the most common method was a booklet produced for patients. Regardless of the education method used, the results of the meta-analysis were as follows. The SMDs of the most severe, average, and current pain in the RCTs were significant. The SMD of worst, average, and current pain were -0.34 (-0.55, -0.13), -0.40 (-0.64, -0.15), and -0.79 (-1.35, -0.23). In the non-randomized studies, the effects on average pain were significant, but those on worst and current pain were not. Conclusions: Education intervention reduced the pain of cancer patients. Therefore, patient education could be considered to be an effective method of cancer pain management. However, our data should be interpreted with caution, and studies using standardized protocols are needed to confirm these observations.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1109-1119
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• 2009

WLAN(Wireless Local Area Network) standard is currently developing with increased wireless internet demand. Though existing IEEE 802.11e demonstrates that data rates exceed 54Mbps with assuring QoS(Quality of Service), wireless internet users can't be satisfied with real communication system. After IEEE 802.11e system, Study trends of IEEE 802.11n show two aspects, enhanced system throughput using aggregation among packets in MAC (Medium Access Control) layer, and better data rates adapting MIMO(Multiple-Input Multiple-Output) in PHY(Physical) layer. But, no one demonstrates IEEE 802.11n system performance results considering MAC and PHY connection. Therefore, this paper adapts MIMO in PHY layer for IEEE 802.11n system based on A-MPDU(Aggregation-MAC Protocol Data Unit) method in MAC layer considering MAC and PHY connection. SVD(Singular Value Decomposition) method with WLAN MIMO TGn Channel is used to analyze MIMO. Consequently, Simulation results show enhanced throughput and data rates compared to existing system. Also, We use Ns-2(Network Simulator-2) considering MAC and PHY connection for reality.