• The KIPS Transactions:PartA
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• v.14A no.3 s.107
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• pp.173-184
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• 2007

Garbage collection in the Java virtual machine is a core function that relieves application programmers of difficulties related to memory management. In this paper, we evaluate and analyze the performance of GenGC and GenRGC, garbage collectors for embedded Java virtual machines. For performance evaluation, we employ CVM, a real embedded Java virtual machine developed by Sun Microsystems, Inc., as a platform and also use a widely-used SpecJVM98 as a set of benchmark programs. To compare the performance of GenGC and GenRGC, we first evaluate the time of garbage collection and the delay time caused by garbage collection. Second, for more detailed performance analysis of GenRGC, we evaluate the time of garbage collection and the delay time caused by garbage collection while changing the sizes of a block and a frame. Third, we analyze the size of storage space required for performing GenRGC, and show GenRGC to be suitable for embedded environment with a limited mont of memory. Since CVM is the most representative one of embedded Java virtual machines, this performance study is quite meaningful in that we can predict the performance of garbage collectors in real application environments more accurately.

• Smart Structures and Systems
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• v.18 no.4
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• pp.663-682
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• 2016

Continuum manipulators as a kind of mechanical arms are useful tools in special robotic applications. In medical applications, like colonoscopy, a maneuverable thin and flexible manipulator is required. This research is focused on developing a basic module for such an application using shape memory alloys (SMA). In the structure of the module three wires of SMA are uniformly distributed and attached to the circumference of a flexible tube. By activating wires, individually or together, different rotation regimes are provided. SMA model is used based on Brinson work. The SMA model is combined to model of flexible tube to provide a composite model of the module. Simulating the model in Matlab provided a platform to be used to develop controller. Complex and nonlinear behavior of SMA make the control problem hard especially when a few SMA actuators are active simultaneously. In this paper, position control of the two degree of freedom module is under focus. An experimental control strategy is developed to regulate a desired position in the module. The simulation results present a reasonable performance of the controller. Moreover, the results are verified through experiments and show that the continuum module of this paper would be used in real modular manipulators.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.64-71
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• 2010

Recently, to achieve high performance of the processor, the cache is splits physically into two parts, one for instruction and one for data. This paper proposes an architecture of asynchronous instruction cache based on mixed-delay model that are DI(delay-insensitive) model for cache hit and Bundled delay model for cache miss. We synthesized the instruction cache at gate-level and constructed a test platform with 32-bit embedded processor EISC to evaluate performance. The cache communicates with the main memory and CPU using 4-phase hand-shake protocol. It has a 8-KB, 4-way set associative memory that employs Pseudo-LRU replacement algorithm. As the results, the designed cache shows 99% cache hit ratio and reduced latency to 68% tested on the platform with MI bench mark programs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.493-497
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• 2005

This paper is about the research of the User Agent implementation under wireless embedded environment, using SIP which is one of protocol components construct the VoIP system. The User Agent is made of the User Agent configuration block, the device thread block to control devices and the SIP stack block to process SIP messages. The device thread consists of the RTP thread and the sound lard device processing block. Futhermore, the SIP stack consist of the worker thread to process proxy events, the SIP transceiver and SIP thread to transfer and receive SIP messages. The H/W platform is a board included the Intel's XScale PXA255 processor, flash memory, SDRAM, Audio CODEC module and wireless LAN threough PCMCIA socket, furthermore a microphone and headphone is used by the audio 1/0. The system has embedded linux kernel 2.4.19. For embedded environment, the function of User Agent and SIP method is diminished. Finally, the resource of system could be reduced about $12.9\%$, compared to overall system resource, by minimizing peripherals control and excepting TCP.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.3
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• pp.240-247
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• 2001

Java is a promising runtime environment for embedded systems because it has many advantages such as platform independence, high security and support for multi-threading. One of the most famous Java run-time environments, Sun's ($PersonalJave^{TM}$) is based on Truffle architecture, which enables programmers to design various GUIs easily. For this reason, it has been ported to various embedded systems such as set-top boxes and personal digital assistants(PDA's). Basically, Truffle uses heavy-weight window managers such as Microsoft vVin32 API and X-Window. However, those window managers are not adequate for embedded systems because they require a large amount of memory and disk space. To come up with the requirements of embedded systems, we adopt Microwindows as the platform graphic system for Personal] ava A WT onto Embedded Linux. Although Microwindows is a light-weight window manager, it provides as powerful API as traditional window managers. Because Microwindows does not require any support from other graphics systems, it can be easily ported to various platforms. In addition, it is an open source code software. Therefore, we can easily modify and extend it as needed. In this paper, we implement Personal]ava A WT using Microwindows on embedded Linux and prove the efficiency of our approach.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.1
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• pp.1-10
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• 2017

Recently, with the ever-increasing complexity of industrial robot systems, it has been greatly attention to adopt a multi-core based motion controller with high cost-performance ratio. In this paper, we propose a software architecture that aims to utilize the computing power of multi-core processors. The key concept of our architecture is to use shared memory for the interplay between threads running on separate processor cores. And then, we have integrated our proposed architecture with an industrial standard compliant IDE for automatic code generation of motion runtime. For the performance evaluation, we constructed a test-bed consisting of a motion controller with Preempt-RT Linux based dual-core industrial PC and a 3-axis industrial robot platform. The experimental results show that the actuation time difference between axes is 10 ns in average and bounded up to 689 ns under $1000{\mu}s$ control period, which can come up with real-time performance for industrial robot.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.421-428
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• 2002

In this paper, we have developed an E-book reader for EBKS XML documents on the embedded Linux environment. This reader operated on a Linux target board parses the EBKS XML documents using the Qt SAX interface and displays the parsed pages through the QWS (Qt Windows System) which is a cross-platform windows toolkit. This reader can be easily and rapidly developed on Linux as well as MS windows and requires less memory than DOM interfaces because it parses with SAX interface.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.103-111
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• 2011

Legacy Java card which adapts a Java platform loads and executes an application when electronics power is provided. However, recently the most Java cards are embedded into a mobile terminal as USIM cards, therefore the power is continually provided for the smart cards. In this case, operation of a Java card system needs to consider its operating system to be advanced in memory management, object management and transaction mechanism. In this paper, we present a high performance Java Card system which is able to have efficient installation, loading and execution of application by applying a new memory management of the smart card that has safe power system.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.435-447
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• 2004

For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.443-451
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• 2023

Machine Learning has introduced many solutions in data science, but its application in IoT faces significant challenges, due to the limitations in memory size and processing capability of constrained devices. In this paper we design an automatic gamma radiation detection and identification embedded system that exploits the power of TinyML in a SiPM micro radiation sensor leveraging the Edge Impulse platform. The model is trained using real gamma source data enhanced by software augmentation algorithms. Tests show high accuracy in real time processing. This design has promising applications in general-purpose radiation detection and identification, nuclear safety, medical diagnosis and it is also amenable for deployment in small satellites.