Hyeontaek Oh

Web-based multi-screen digital signage

Web-based multi-screen digital signage system is designed to show a multimedia content via multiple signage screens which are connected by a network. In this demonstration, a novel method to control multi-screen digital signage is proposed. The proposed method uses standard web technologies to display same contents and seamless moving each devices screen.

Demonstration of Smart u-Learning System

The Smart u-Learning System is designed to provide an interactive and social learning environment that accommodates emerging devices. This demonstration will show how teachers and students can use its interactivity and social features in live lecture situations.

Maximizing energy efficiency in off-peak hours: A novel sleep scheme for WLAN access points

The number of wireless access points (APs) have increased rapidly in recent years to support increasing demands of wireless local area network. However, some of the research findings show that many of these APs are actually idle mainly during off-peak hours, i.e., there is no active user to support within their coverage areas during that time. Nevertheless, to identify availability of users, all APs are remained powered-on always regardless the presence or absence of any active user inside their coverage areas. To save energy during off-peak hours in idle APs, sleep mechanism could be applied. In this paper, we propose a novel sleep mechanism for IEEE 802.11 wireless local area network APs. In our solution, an AP moves into sleep mode to maximize its energy efficiency (EE) while not harming traffic delay requirements. To decide length of sleep interval of an AP, we propose a dynamic sleep boundary decision algorithm which dynamically sets upper and lower bound of sleep duration considering traffic arrival rate and traffic delay requirements at a given time. Numerical results show the proposed scheme can improve EE of an AP significantly compared to the existing schemes without violating traffic delay requirements.

Issues and prospects for energy saving networks

Studies on existing and future networks aimed at building an energy saving networks have been conducted by global standard groups such as GreenTouch, IETF, and ITU-T. Future networks deployed without considering energy issues will encounter major problems related to network maintenance and operating costs, and ICT has been a recent area of interest with respect to saving energy. Sensor networks/ad hoc networks have been studied for a number of years in efforts to overcome battery constraints. Meanwhile, research on reducing the overall energy dissipation at the network level has been conducted by GreenTouch. In this paper, we introduce research issues and prospects for energy saving networks.

WoO based emergency service support functions for smart home care.

Under the concept of Web-of-Object (WoO), emergency service is one of the key components in smart home care. Most distinctive characteristics of the emergency service are prompt detection, confidential decision making, and immediate reaction. For that, besides the general service management, the sensor data management, context processing, and communication functions are designed under the name of support functions. A use case with service procedures shows how they work in between the service platform and end devices.

Energy-efficient dynamic load distribution for heterogeneous access networks

In heterogeneous wireless access networks, it is important to achieve high variability of access resources. Bandwidth Aggregation (BAG) is considered to be a promising solution for this objective. However, power consumption has not been adequately addressed, although prolonging the battery life time of mobile devices with low power consumption has received attention lately. In this paper, we propose a novel dynamic energy-efficient load distribution algorithm for heterogeneous wireless networks. For the optimal load distribution, which is challenging combinatorial problem, we propose simple greedy load distribution algorithms that are inspired by the mathematical background of the Lagrangian algorithm. Furthermore, we propose another heuristic algorithm that extends the proposed algorithm when the retransmission scheme is hired for packet loss (e.g, TCP). Finally, an extensive Network Simulator 2 (NS2) simulation under various practical configurations demonstrates that the proposed algorithm could converge to the optimal distribution point with low complexity. Furthermore, it gives significantly increased the battery life time of mobile device with guarantee required Quality of Service (QoS) constraints.

DREAD-R: Severity Assessment of ONOS SDN Controller

In few past years, popularity of Software Defined Networking (SDN) among academia and industry is rapidly increased, and users are conferenced about choosing suited and secured SDN controller. Recently, Open Network Operating System (ONOS), which provides the control plane for SDN, appears as best choice for service provider in term of high availability, scalability, and security. There are some existing models for security assessment of SDN. However, there is still a room for more assessments. This paper address the severity assessment of ONOS using proposed DREAD-R model which considers traditional DREAD (Damage potential, Reproducibility, Exploitability, Affected users and Discoverability) model with additional “Reputation” parameter. This paper found that control plane vulnerabilities are critical in nature and disrupt entire network functions and need immediate attention for solutions.

Objectification of feedback based trust evaluation considering social relationship in sharing economy

With the growth of sharing economy, P2P resource sharing services are combined with social networks for improving user experience and giving more trustworthiness to users. For trust management, many P2P resource sharing services adopt feedback-based reputation system. Since peers in services have their social relationship in the community, reputation includes not only trust related to services but also subjective social trust which causes bias of reputation. In this paper, we propose the method that objectifies feedback-based trust by removing social trust from rating points. We conduct simulation and verify the proposed method can objectify feedback-based trust preciously with optimized parameters by using lambda square discrepancy measure.

Hub-based personal web-enabled cross-device application sanghong ahn

As the Internet of Things has emerged, it has become possible to develop applications and services through various types of input / output using things as well as various graphic displays. In view of the development of such interfaces, a distributed user interface (DUI) is emerging in which a plurality of devices are simultaneously used to utilize one application service. In order to activate a DUI-based application, a method for the user to organize a users devices into groups and a methodology for service providers to describe their services in the form of DUI should be presented. We propose a hub-based personal web cross-device application framework. The framework consists of a server side markup language extension, a front end library, and a hub system that are implemented through a web-based browser simulator. We expect this framework to be applied as a browser feature so that DUI can provide a better user experience.

Trust visualization for object management in Internet of Things

This paper proposed trust visualization for object management in Internet of Things environment. Based on the proposed system, trust based object visualization methods are introduced. Actual implementation shows that graph-based trust visualization helps user perceptions to handle various related objects.