• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.27-31
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• 2012

This paper proposes a new method of character segmentation in a grayscale image using the standard deviation. Firstly, the proposed method scans vertically the region of interest in an image in order to calculate a standard deviation for each scan line. Characters' standard deviations are much bigger than the background's. Therefore, it is possible to segment characters vertically using the differentiation of those two types of standard deviations. Secondly, the method scans each vertically segmented image horizontally at this time, and then segments each image similarly. The proposed method is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiments were conducted by using credit card images. The results show that the proposed algorithm is quite successful for most credit cards. However, the method fails in some credit cards with strong background patterns.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.312-318
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• 2011

USN technology will be applied to various fields such as logistics, transportation, government, health, welfare and environment and will be settled down by basic infrastructure of a future society. In this study, we analyzed sensor networks structure based on IEEE 802.15.4 and implemented the sensor monitoring system using Zigbee modules. For implementation of real-time sensor monitoring system, we designed Linux-based development environment and the sensor-specific component. The result of this paper may be utilized in such areas lighting system, intrusion detection, fire detection, detection and notification of abnormal conditions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.126-133
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• 2004

Lots of researches and applications on the automated overhead cranes in shops have been done for some decades, but a few successful results are reported. Integrated crane control systems designed by famous engineering companies are still expensive and are not satisfactory in view of maintenance and reliability. A more reasonable control system fit to requirements of manufacturing industries is suggested in the study. The new deigned system has superior capabilities for anti-sway of rope and position control. The controller for automated operations is composed of a Linux-based PC for non real-time control and a high-speed PLC for hard real-time control. Some algorithms required for coil yard operations as well as main control algorithms such as reference position generation, position control and anti-sway control have been designed and fully tested on the new crane simulator. The designed crane control system showed satisfactory performance on position control accuracy and anti-sway of rope. The maximum positional error is 8mm and the maximum sway error is 0.1 degrees. The suggested control strategies have been successfully applied to the 10-1 crane in No. 4 CGL of in the Kwangyang Steel Works and in commercial operation.

• Journal of Advanced Navigation Technology
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• v.9 no.1
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• pp.61-69
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• 2005

TCP and UDP is a transport layer protocol of Internet. TCP is a connection oriented protocol which supports a reliable data transfer by offering error and flow control, but it bring a transmission delay. On the other hand, the UDP is a connectionless protocol which does not carry out error and flow control, but it guarantees a realtime transmission. There are hardly any protocols which supports not only realtime functions but also data reliability. In this paper, we have designed and implemented a new TCP mode option which supports reliable realtime transmission. Our designed TCP performs an error recovery process during a fixed amount of time. This time is negotiated during the connection establishment phase. Our designed TCP is tested in real environments, and we find that it is relatively faster than the standard TCP and more reliable than the UDP. It can be used for the reliable transfer of realtime multimedia data.

• Journal of KIISE
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• v.44 no.6
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• pp.566-572
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• 2017

As NAND flash storage is being widely used, its simulation methodologies have been studied in various aspects such as performance, reliability, and endurance. As a result, there have been advances in NAND flash storage simulation for both functional modeling and timing modeling. However, in addition to these advances, there is a need to drastically reduce the long simulation time that is required to evaluate the aging effect on flash storage. This paper proposes a so-called multi-core scalable real-time flash storage simulation method, which can control the simulation speed according to the user's preference. According to this method, it is possible to speed up the simulation in proportion to the number of CPU cores arbitrarily given while guaranteeing the correctness of the simulation result. Using our simulator implemented in the form of the Linux kernel module, we demonstrate the multi-core scalability and correctness of the proposed method.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.271-281
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• 2007

Real-time support of embedded OS is not optional, but essential in contemporary embedded systems. In order to achieve these system#s real-time property, it is crucial that schedulability analysis for tasks having its property have been accomplished before system execution. Acquiring Worst-Case Execution Time(WCET) of task is a core part of schedulability analysis. Because traditional WCET tools analyze only its estimation of application task(i.e. program), it is not considered that application tasks are affected by scheduling primitives(e.g. scheduler, interrupt service routine, etc.) of OS when it schedules them. In this paper, we design and implement WCET analysis tool which deliberates on scheduling primitives of system using embedded Linux widely used in embedded OSes. This tool can estimate either WCET of normal application programs or corresponding primitives which have an influence on schduling property in embedded Linux kernel. Therefore, precision of estimation about schedulability analysis is improved. We develop this tool as Eclipse#s plug-in to work properly in any platform and support convenient interface or functionality for user.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.90-103
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• 2006

There are many file systems in various operating systems. Those are usually designed for server environments, where the common cases are usually 'multiple active users', 'great many small files' And they assume a big main memory to be used as buffer cache. So the existing file systems are not suitable for resource hungry embedded systems that process multimedia data streams. In this study, we designed and implemented a new file system which efficiently stores and retrieves multimedia data steams. The proposed file system has a very simple disk layout, which guarantees a quick disk initialization and file system recovery. And we introduced a new indexing-scheme, called the time-based indexing scheme, with the file system. With the indexing scheme, the file system maintains the relation between time and the location for all the multimedia streams. The scheme is useful in searching and playing the compressed multimedia streams by locating exact frame position with given time, resulting in reduction of CPU processing and power consumption. The proposed file system and its APIs utilizing the time-based indexing schemes were implemented firstly on a Linux environment, though it is operating system independent. In the performance evaluation on a real DVR system, which measured the execution time of multi-threaded reading and writing, we found the proposed file system is maximum 38.7% faster than EXT2 file system.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.345-354
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• 2004

In these days, such services are popularized as E-commerce, E-government, multimedia services, and home networking applications. Most web traffics generated contemporarily basically use the Hyper Text Transfer Protocol(HTTP). Unfortunately, the HTTP is improper for these applications that comprise significant components of the web traffics. In this paper, we introduce a real-time contents compression architecture that maximizes the web service performance as well as reduces the response time. This architecture is built into the linux kernel-based web accelerating module. It guarantees not only the freshness of compressed contents but also the minimum time delay using an server-state adaptive algorithm, which can determine whether the server sends the compressed message considering the consumption of server resources when heavy requests reach the web server Also, We minimize the CPU overhead of the web server by exclusively implementing the compression kernel-thread. The testing results validates that this architecture saves the bandwidth of the web server and that elapsed time improvement is dramatic.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.781-786
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• 2004

In these days, such services are popularized as E-commerce, E- government, multimedia services, and home networking applications. Most web traffics generated contemporarily basically use the Hyper Text Transfer Protocol(HTTP). Unfortunately, the HTTP is improper for these applications that comprise significant components of the web traffics. In this paper, we introduce a real-time contents compression architecture that maximizes the web service performance as well as reduces the response time. This architecture is built into the linux kernel-based web accelerating module. It guarantees not only the freshness of compressed contents but also the minimum time delay using an server-state adaptive algorithm, which can determine whether the server sends the compressed message considering the consumption of sewer resources when heavy requests reach the web server. Also, We minimize the CPU overhead of the web server by exclusively implementing the compression kernel-thread. The testing results validates that this architecture saves the bandwidth of the web server and that elapsed time improvement is dramatic.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.173-178
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• 2015

Cloud systems are efficient models that can utilize various infrastructures, platforms, and applications regardless of the type of clients. This paper proposes a cloud-based integrated development environment (IDE) for robot software development which would make software development easier. The proposed system provides robot simulation to test the robot HW modules or robot systems for development and testing of software operating in a robot system with two or more different operating systems (OS) such as Windows, Linux, and real-time OS. This paper implements and evaluates the proposed system using OPRoS [33].