Moon-Haeng Cho

A low-power real-time operating system for ARC (actual remote control) wearable device

In recent years, consumer electronic devices have been expanding their application domains from traditional consumer electronic devices such as cellular phones, PDAs(Personal Digital Assistants), PMPs(Portable Multimedia Players), Navigation, to Next Generation Personal Computers(NGPCs) such as eating consumer electronic devices, implanted consumer electronic devices, wearable consumer electronic devices. A wearable consumer electronic device is a computer that is subsumed into the personal space of the user, controlled by the user, and is always on and always accessible. Therefore, among the most salient aspect of wearable consumer electronic devices should be small form factor and long battery lifetime. In this paper, we propose a novel low-power real-time operating system (RTOS) specialized for the ARC(Actual Remote Control). An ARC is a wearable wristwatch-type remote controller; it also can serve as a universal remote control for various consumer electronic devices. The proposed RTOS has about 9KB footprints and is equipped with low-power techniques composed of the dynamic power management and the device power management. Experimental results with wearable application show that we can save energy up to 47 % using the proposed low-power techniques.

eRTOS : The low-power real-time operating system for wearable computers

A wearable computer is a computer that is subsumed into the personal space of the user, controlled by the user, and is always on and always accessible. Therefore, among the most salient aspect of wearable computers should be small form factor and long battery lifetime. In this paper, we have designed and implemented a low-power real-time operating system (called “eRTOS”) specialized for wearable computers. eRTOS has about 9KB footprint and is equipped with low-power techniques composed of the dynamic power management and the device power management. Experimental results with wearable applications show that we can save energy up to 47 % using the proposed low-power techniques.

Design and Implementation of Real-time Implanted Kernel, RTiK to Support Real-time for a Test Set based on Windows

Recently, as new weapons are being developed, test equipments to test their functions inevitably require real-time features. However, since test equipments based on Windows can not support real-time requirements, we have no choice but to use third-party solutions such as RTX or INtime. This leads to increase the development cost of each test equipment. This paper suggests an real-time implemented kernel(RTiK) which operates as a device driver on Windows. RTiK provides another timer using the Local APIC of x86 microprocessors. It supports real-time requirements by periodically executing the required services using Windows-independent timer interrupts to guarantee task deadlines. To reduce the interrupt latency, we used deferred procedure calls provided by Windows. We also used the export driver to implement and modify user-defined functions without accessing the RTiK internals. Using an oscilloscope, we prove that the RTiK kernel proposed in this paper guarantees up to 0.1ms periods.

Real-Time Task Scheduling Algorithm using a Multi-Dimensional Methodology for Embedded Real-Time Operating Systems

In recent years, embedded systems such as cellular phones, Portable Multimedia Player, intelligent appliance, automobile engine control are reshaping the way people live, work, and play. Thereby, services application to guarantee various requirements of users become increasingly sophisticated and complicated, such embedded computing platforms use real-time operating systems (RTOSs) with time determinism. These RTOSs must not only provide predictable services but must also be efficient and small in size. Kernel services should also be deterministic by specifying how long each service call will take to execute. Having this information allows the application designers to better plan their real-time application software so as not to miss the deadline of each task. In this paper, we present the complete generalized real-time scheduling algorithm using multi-dimensional methodology to determine the highest priority in the ready list with 2r levels of priorities in a constant time without additional memory overhead.

Design and Performance Analysis of Framework for Guaranteeing QoS of Robot Components

The growth of CPU and communication technologies have made an important contribution to the development of the network-based intelligent service robots. Robot software must guarantee the correct execution and safety of the user. To achieve this, it is highly required to research how to guarantee the QoS of the components which organize a robot software. The QoS of robot components aims to execute the component stably by processing the data stream in a correct way. By guaranteeing QoS, we can achieve the intelligence and stability of robots. In this paper, we design and implement the QoS framework to guarantee the QoS of robot components on robot platforms with limited resources. We also measure the response times of QoS requests and present the performance analysis results about it.

Implementation and Performance analysis of a Framework to Support Real-Time of Robot Components

In ubiquitous environments, the real-time features are necessary to insure the QoS of the intelligent service robots. In this paper, we design and implement a real-time framework for intelligent service robots to support real-time features. The real-time framework to support real-time scheduling services is implemented on the general operating systems. We solve the problem that the scheduler of a general operating system can not support real-time features. This paper also proposes realtime scheduling services to guarantee the QoS of real-time robot applications. We implemented the proposed real-time framework on the Windows operating system and conducted some performance experiments. The experimental results show that the proposed real-time framework can improve thread response times and it has slight performance overhead of .

Design and Implementation of eRTOS Real-time Operating Systems for Wearable Computers

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user`s QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.

DVSMT: Dynamic Voltage Scaling for Scheduling Mixed Real-Time Tasks

In this paper, we address a power-aware scheduling algorithm for mixed real-time tasks. A mixed-task system consists of periodic and sporadic tasks, each of which is characterized by its worst-case execution requirements and a deadline. We propose a dynamic voltage scaling algorithm called DVSMT, which dynamically scales down the supplying voltage (and thus the operating frequency) using on-line slack distribution when jobs complete earlier while still meeting their deadlines. Simulation results show that DVSMT saves up to 60% more than the existing algorithms both in the periodic and mixed task systems.

Design and Implementation of Wrapper to Support POSIX Standards on UbiFOS TM Real-Time Operating System

Recently, Embedded systems are different with the past as loading of a simple application program that executed specific functions according to the use and are evolved in the digital convergence integrated multimedia functions and then the complication of the application program is remarkably increased. This application program is combined and evolved with many application program in accordance with the demand of the age. For develope and manage this developing application is necessary standardized interface between developer and manager. POSIX was developed as the standard of the operating system in the standard interface which has the open system structure in computing system, and there is a posix.4 to standard for the system demands the loading of real-time operating system like a digital convergence devices. In this paper, we present the contents of designing and implementing the real-time operating system UbiFOSTM to wrapper for supporting the POSIX.4. Also, Experimental results show that implemented wrapper to application program standardizing POSIX.4 in linux and UbiFOSTM is slight only .

Power-Aware Scheduling for Mixed Real-Time Tasks

In this paper, we address a power-aware scheduling algorithm for a mixed real-time system which consists of periodic and sporadic tasks, each of which is characterized by its minimum period, worst-case execution requirement and deadline. We propose a dynamic voltage scaling algorithm called DVSMT(DVS for mixed tasks), which dynamically scales down the supplying voltage(and thus the frequency) using on-line distribution of the borrowed resources when jobs complete while still meeting their deadlines. With this scheme, we could reduce more energy consumption. As the proposed algorithm can be easily incorporated with RTOS(Real-Time Operating System), it is applicable for handhold devices and sensor network nodes that use a limited battery power. Simulation results show that DVSMT saves up 60% more than the existing algorithms both in the periodic-task and mixed-task systems.