• ETRI Journal
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• v.29 no.3
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• pp.270-280
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• 2007

In Linux, real-time tasks are supported by separating real-time task priorities from non-real-time task priorities. However, this separation of priority ranges may not be effective when real-time tasks make the system calls that are taken care of by the kernel threads. Thus, Linux is considered a soft real-time system. Moreover, kernel threads are configured to have static priorities for throughputs. The static assignment of priorities to kernel threads causes trouble for real-time tasks when real-time tasks require kernel threads to be invoked to handle the system calls because kernel threads do not discriminate between real-time and non-real-time tasks. We present a dynamic kernel thread scheduling mechanism with weighted average priority inheritance protocol (PIP), a variation of the PIP. The scheduling algorithm assigns proper priorities to kernel threads at runtime by monitoring the activities of user-level real-time tasks. Experimental results show that the algorithms can greatly improve the unexpected execution latency of real-time tasks.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.106-108
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• 2001

본 논문에서는 임베디드 자바 가상 대신(Embedded Java Virtual Machine)과 임베디드 실시간 운영체제(Embedded Real-Time Operating System)인 iRTOS$^{TM}$를 통합하기 위한, 설계 및 구현 내용을 기술하고자 한다. 인터넷 가전을 위한 실시간 운영체제 기반의 통합 환경은 각 가정에서 사용하는 정보 가전 제품들을 인터넷에 연결하여 사용함으로써 사용자에게 좀 더 효율적이며. 편리한 서비스를 제공할 수 있다. 또한 어떠한 플랫폼에도 구애 받지 않고 동작 할 수 있는 자바를 실행하기 위한 내장형 JVM 의 추가로, 기존의 플랫폼 의존적인 방법을 벗어나 어떠한 가전 기기상해서도 자바로 개발된 모든 기능들을 동일한 조건으로 동작시킬 수 있다는 장점을 갖는다. 본 논문에서는 통합 설계서의 세부 내용과 통합 방법에 대해 언급하고자 한다.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.264-267
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• 2000

This paper describes a real-time 3D sound localization algorithm to be implemented with the use of a Bow power embedded DSP. This algorithm first divides the audible frequency band into three, on the basis of the analysis of the sound reflection and diffraction effects through different media from a certain sound source to human ears, and then in each subband a specific procedure is devised fur the 3D sound localization so as to operate real-time on a low power embedded DSP This algorithm aims at providing a listener with the 3D sound effects through a headphone at low cost and low power consumption.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.4
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• pp.214-221
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• 2003

This paper shows an implementation of video codec (coder/decoder) on an embedded system. The video codec supports both H.261 and H.263 standards. For efficient real-time processing, the video codec is partitioned into a software module and a hardware module. Both modules are codesigned on an embedded system. The software module is processed on a real-time operating system and a RISC processor. It cooperates with the hardware module to compress and decompress images in real time. AMBA (Advanced Microcontroller Bus Architecture) AHB (Advanced High-performance Bus) is used as the system bus. The hardware module works both as AHB masters and as AHB slaves. The encoder part of the hardware module operates in a pipelines mode to compress images in real time. The video codec compresses 15 CIF frames and simultaneously decompresses 15 CIF frames in a second according to H.261 or H.263 standard at 33 MHz frequency.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.299-306
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• 2003

This paper formulates a problem of embedded real-time system re-engineering, and presents its solution approach. Embedded system re-engineering is defined as a development task of meeting performance requirements newly imposed on a system after its hardware and software have been fully implemented. The performance requirements nay include a real-time throughput and an input-to-output latency. The proposed solution approach is based on a bottleneck analysis and nonlinear optimization. The inputs to the approach include a system design specified with a process network and a set of task graphs, task allocation and scheduling, and a new real-time throughput requirement specified as a system's period constraint. The solution approach works in two steps. In the first step, it determines bottleneck precesses in the process network via estimation of process latencies. In the second step, it derives a system of constraints with performance scaling factors of processing elements being variables. It then solves the constraints for the performance staling factors with an objective of minimizing the total hardware cost of the resultant system. These scaling factors suggest the minimal cost hardware upgrade to meet the new performance requirement. Since this approach does not modify carefully designed software structures, it helps reduce the re-engineering cycle.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.4
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• pp.231-238
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• 2017

Detecting small infrared targets from the low-SCR images at a long distance is very hard. The previous Local Contrast Method (LCM) algorithm based on the human visual system shows a superior performance of detecting small targets by a background suppression technique through local contrast measure. However, its slow processing speed due to the heavy multi-scale processing overhead is not suitable to a variety of real-time applications. This paper presents a lightweight real-time small target detection algorithm, called by the Improved Selective Local Contrast Method (ISLCM), to reduce the scale-invariant computational overhead. The proposed ISLCM applies the improved local contrast measure to the predicted selective region so that it may have a comparable detection performance as the previous LCM while guaranteeing low scale-invariant computational load by exploiting both adaptive scale estimation and small target feature feasibility. Experimental results show that the proposed algorithm can reduce its computational overhead considerably while maintaining its detection performance compared with the previous LCM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10C
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• pp.983-991
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• 2009

While H.264/AVC is in wide use for multimedia applications such as DMB and IPTV service, we have limited usage cases for embedded real-time applications due to its high computational demand. The paper provides judicious guide line for optimization method selection, by presenting the detailed experiments data through the development process of a real time H.264 software encoder on embedded DSP. The experimental analysis includes an intensive profiling analysis, fast algorithm application, optimal memory assignment, and intrinsic-based instruction selection. We have realized a real-time software that encodes CIF resolution videos 15 fps on TMS320DM64x processors.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.3
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• pp.126-133
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• 2009

There are already many researches providing u-Healthcare service, but they have left problems to be improved. First of all, the transmission range between sensor nodes and the gateway are restricted. Hence, patients feel uncomfortable because of they need to possess or locate closed to a gateway all the time when they aggregates their medical data. Also, the existing systems have not considered life environment that is important to analyze patient's diseases. Moreover, a guardian need to located close to patient or possess a mobile device that monitors a patients' status in real time when they are in outdoor. In this research, we present multi-hop packet transfer algorithm and compilation of life environment which help improve the problem of the existing researches. Likewise, we designed and implemented a medical information database and a real-time web monitoring system that manage patients' personal history and monitor a patients' status in real time. In this paper, we design and implement the u-Healthcare system based on mobile environment and we present a result when we tested our u-Healthcare system in scenario environment.

• Journal of Korea Game Society
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• v.20 no.3
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• pp.45-54
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• 2020

An automated system using a embedded board is required to generate the notation input of the offline Go game. This paper integrates shape and color information of the objects on the Go game board for light-insensitive processing and reduces the computation step. This paper combined the detection of obstacles using connected components with the computation of canny edge detection and HSV-based detection. As a result, the processing time is reduced in the embedded environment so that reliable notation can be automatically stored even in real-time play environment.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.592-597
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• 2003

In this paper, some differential geometric conditions for the observer using a recurrent neural network are provided in terms of a stochastic nonlinear system control. In the stochastic nonlinear system, it is necessary to make an additional condition for observation of stochastic nonlinear system, called perfect filtering condition. In addition, we provide a observer using a recurrent neural network for the observation of a stochastic nonlinear system with the proposed observation conditions. Computer simulation shows that the control performance of the stochastic nonlinear system with a observer using a recurrent neural network satisfying the proposed conditions is more efficient than the conventional observer as Kalman filter