Seungho Yoo

Poster: A Multi-Drone Platform for Empowering Drones' Teamwork

The rapid development of UAV technology has opened up numerous applications. Further, cooperating drones\footnote{In this paper, we refer to all types of UAVs as drones.} possess a great potential in various areas of applications. Yet, there has not been a platform for a fleet of drones. It is rather difficult to control multiple drones through a single ground control station. In fact, drones need to consistently exchange flight information to maintain the formation of the fleet and follow the commands given from the GCS. Thus, drones need a robust network established among the fleet to provide a fleet control. In this paper, we propose Net-Drone, a multi-drone platform for applications that require cooperation of multiple drones. Net-Drone is equipped with strong network functionalities to provide a control system for a fleet of drones. Through case studies conducted with a prototype implementation, the proposed system is demonstrated. Video of the conducted case study can be found in http://youtu.be/lFaWsEmiQvw.

FASE: Fast authentication system for e-health

For the past few decades, it is common to observe the patients paper work at the local hospital. Even though the same personal information is used, a novel way to actually decrement the amount of these paper works does not exist. In this paper, we introduce QR code based e-health authentication system to reduce the redundant paper work and obtain patients health record easily and securely in the local hospital. With our proposed scheme, we believe that it will improve efficiency in terms of the cost and time for both patient and the hospital and protect patients personal information.

Constructing a reliable and fast recoverable network for drones

In recent years, due to the technological development of various kinds of drones, also known as unmanned aerial vehicles (UAVs), drones have emerged as an effective solution for a wide area of applications. In such applications, employing multiple drones promises a better way to carry out a given mission than employing a single drone. To utilize multiple drones, all drones should establish a network that can provide connectivity among themselves. In this paper, we propose GCS-routing, a routing protocol for multiple drones employed by a ground control system (GCS). GCS-routing utilizes the information of drones that can be obtained from GCS, such as geographic information and per-drone flight schedules. The actual implementation of GCS-routing was applied to a fleet of drones, and evaluated in various aspects.

Devising Mobile Sensing and Actuation Infrastructure with Drones

Vast applications and services have been enabled as the number of mobile or sensing devices with communication capabilities has grown. However, managing the devices, integrating networks or combining services across different networks has become a new problem since each network is not directly connected via back-end core networks or servers. The issue is and has been discussed especially in wireless sensor and actuator networks (WSAN). In such systems, sensors and actuators are tightly coupled, so when an independent WSAN needs to collaborate with other networks, it is difficult to adequately combine them into an integrated infrastructure. In this paper, we propose drone-as-a-gateway (DaaG), which uses drones as mobile gateways to interconnect isolated networks or combine independent services. Our system contains features that focus on the service being provided in the order of importance, different from an adaptive simple mobile sink system or delay-tolerant system. Our simulation results have shown that the proposed system is able to activate actuators in the order of importance of the service, which uses separate sensors’ data, and it consumes almost the same time in comparison with other path-planning algorithms. Moreover, we have implemented DaaG and presented results in a field test to show that it can enable large-scale on-demand deployment of sensing and actuation infrastructure or the Internet of Things (IoT).

Link-Aware Reconfigurable Point-to-Point Video Streaming for Mobile Devices

Even though people of all social standings use current mobile devices in the wide spectrum of purpose from entertainment tools to communication means, some issues with real-time video streaming in hostile wireless environment still exist. In this article, we introduce CoSA, a link-aware real-time video streaming system for mobile devices. The proposed system utilizes a 3D camera to distinguish the region of importance (ROI) and non-ROI region within the video frame. Based on the link-state feedback from the receiver, the proposed system allocates a higher bandwidth for the region that is classified as ROI and a lower bandwidth for non-ROI in the video stream by reducing the videos bit rate. We implemented CoSA in a real test-bed where the IEEE 802.11 is employed as a medium for wireless networking. Furthermore, we verified the effectiveness of the proposed system by conducting a thorough empirical study. The results indicate that the proposed system enables real-time video streaming while maintaining a consistent visual quality by dynamically reconfiguring video coding parameters according to the link quality.

Exploiting User Movement Direction and Hidden Access Point for Smartphone Localization

In this paper, we propose a global positioning system-less localization method, called Hidden Access Point Estimation-based Localization (HAPEL) to pinpoint user’s current position in an underground or indoor environment, especially where access points (APs) are placed scarcely in that two or less Wi-Fi APs are within the scanning range. Conceptually, HAPEL enhances the weighted centroid localization (WCL) by exploiting hidden APs and estimating the direction of user movement. The movement direction can be estimated with digital compass, accelerometer and gyroscope, all of which are usually installed on smartphones, and the estimation result is used to choose which hidden APs participate in the WCL. We have conducted a performance evaluation study on HAPEL in comparison with WCL and fingerprint methods in an empirical test-bed. The results indicate that HAPEL improves the accuracy of the WCL significantly.

A Collaborative Framework of Enabling Device Participation in Mobile Cloud Computing

Cloud Computing attracts much attention in the community of computer science and information technology because of resource efficiency and cost-effectiveness. It is also evolved to Mobile Cloud Computing to serve nomadic people. However, any service in Cloud Computing System inevitably experiences a network delay to access the computing resource or the data from the system, and entrusting the Cloud server with the entire task makes mobile devices idle. In order to mitigate the deterioration of network performance and improve the overall system performance, we propose a collaborative framework that lets the mobile device participate in the computation of Cloud Computing system by dynamically partitioning the workload across the device and the system. The proposed framework is based on it that the computing capability of the current mobile device is significantly enhanced in recent years and its multi-core CPU can employ threads to process the data in parallel. The empirical experimentation presents that it can be a promising approach to use the computing resource of the mobile device for executing computation-intensive tasks in Cloud Computing system.

Avss: Airborne video surveillance system

Most surveillance systems only contain CCTVs. CCTVs, however, provide only limited maneuverability against dynamic targets and are inefficient for short term surveillance. Such limitations do not raise much concern in some cases, but for the scenario in which traditional surveillance systems do not suffice, adopting a fleet of UAVs can help overcoming the limitations. In this paper, we present a surveillance system implemented with a fleet of unmanned aerial vehicles (UAVs). A surveillance system implemented with a fleet of UAVs is easy to deploy and maintain. A UAV fleet requires little time to deploy and set up, and removing the surveillance is also virtually instant. The system we propose deploys UAVs to the target area for installation and perform surveillance operations. The camera mounted UAVs act as surveillance probes, the server provides overall control of the surveillance system, and the fleet platform provides fleet-wise control of the UAVs. In the proposed system, the UAVs establish a network and enable multi-hop communication, which allows the system to widen its coverage area. The operator of the system can control the fleet of UAVs via the fleet platform and receive surveillance information gathered by the UAVs. The proposed system is described in detail along with the algorithm for effective placement of the UAVs. The prototype of the system is presented, and the experiment carried out shows that the system can successfully perform surveillance over an area set by the system.

Empowering Drones’ Teamwork with Airborne Network

We propose a unified platform for multiple unmanned aerial vehicles (UAV). Recently, the UAV technology has seen a great development. However, the capability of single drone is yet limited by its physical features. To better enhance the capability of drones, we have devised and implemented a fleet based multi-UAV platform. Our proposed platform consists of powerful network functions and enhanced control and sensing algorithms, so that a unified fleet control can be accomplished. Further, it provides a platform for applications that require multiple UAVs working together. The network functions of the proposed platform achieves a strong connectivity and robustness, and a precise relative and absolute localization enables a fleet based control system. With the help of core modules, the proposed platform achieves a well controlled fleet flight and network management.

Augmenting small cell with personal area cell for performance improvement

Since mobile traffic has been increased tremendously due to popularization of high-end mobile devices, many mobile carriers and smartphone manufacturers have put their best effort on solving the capacity problem. Small cell is introduced as an idea for the solution, and various mobile carriers have installed small cells to provide more bandwidth to areas that have too much traffic to be handled by single cell tower. In this paper, we state a problem that is an extended version of current capacity problem, and argue that the problem cannot be solved by installing small cells only. Therefore, we propose the concept of Personal Area Cell (PAC) that is portable and able to perform multi-hop transmissions. In order to justify the proposed problem and solution, a traffic model is designed and simulated. The simulation results show that small cell based network is inefficient when population and traffic of each cell are changed over time while PAC adopted network is cost-efficient and adaptive to such the change.