Chun-Hyon Chang

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The ideas and findings in this report should not be construed as an official DoD position. It is published in the interest of scientific and technical information exchange. Permission to reproduce this document and to prepare derivative works from this document for internal use is granted, provided the copyright and \'No Warranty\' statements are included(More)
In this paper, we introduce the target scenario of our HELISCOPE project with the emphasis on the four modes for flying-camera task. We also explain the control points that are considered as the interfaces where the on-flight embedded software and mechanical implementation of the unmanned helicopter are contacted for the autopilot necessarily used in(More)
Autonomous landing for fixed-wing aircraft is one of issues in smart Unmanned Aerial Vehicles (UAV). In this paper, we present a robust real-time line tracking algorithm for UAV using image processing. In the proposed algorithm, we first reduce computation region, and then transform to Hough space to detect lines in frame. Finally, the line tracking is(More)
Timeliness-guaranteed computing considering the worst case can hardly be accomplished at run time because of the uncertainty caused by resource sharing, asynchronous events and conflicting timing constraints between tasks. An easier way to reach it is to do some off-line analysis from design time with predictable characteristics of tasks. The TMO model(More)
HELISCOPE is the name of a project support by MKE (Ministry of Knowledge & Economy) of Korea to develop flying-camera services that transmits the scene of a fire by an unmanned helicopter. In this paper, we introduce the design and implementation of the OFP (Operational Flight Program) for the unmanned helicopter's navigation based on the well-known TMO(More)
Real-Time Simulation is a most important tool that allows for prediction of system behavior in response to operator actions and events via the use of real-time and archived data. Virtual testing of operator actions prior to implementation can reveal potential problems, hence reducing human errors and the risk of service power system interruptions.(More)
For enforcing security, Android platform uses authorizing system which grants permission per application at install-time. With authorized privilege, user applications can modify and delete user's personal information. Therefore, inspection of granted permiss ion usage can be used to detect security vulnerabilities. ISO/IEC 25 010 defines software product(More)
Analyzing execution time in static manner is tedious, due to unbounded external inputs in loops and control flow. Parametric WCET analysis uses parameter to get a user input. It can give formula expressed in the input variables of a program during analysis time. This can help an analyzer to offer more accurate and flexible result. But recently, it grows(More)