• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.369-372
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• 2002

In this research, a vision system for detecting tool breakage which is hardly detected by such indirect in-process measurement method as acoustic emission, cutting torque and motor current was developed and embedded into a PC-NC system. The vision system consists of CMOS image sensors, a slit beam laser generator and an image grabber board. Slit beam laser was emitted on the tool surface to separate the tool geometry well from the various obstacles surrounding the tool. An image of tool is captured through two steps of signal processing, that is, median filtering and thresholding and then the tool is estimated normal or broken by use of change of the centroid of the captured image. An air curtain made by the jetting high-pressure air in front of the lens was devised to prevent the vision system from being contaminated by scattered coolant, cutting chips in cutting process. To embed the vision system to a Siemens PC-NC controller 840D NC, an HMI(Human Machine Interface) program was developed under the Windows 95 operating system of MMC103. The developed HMI is placed in a sub window of the main window of 840D and this program can be activated or deactivated either by a soft key on the operating panel or M codes in the NC part program. As the tool breakage is detected, the HMI program emit a command for automatic tool change or send alarm to the NC kernel. Evaluation test in a high speed tapping center showed the developed system was successful in detection of the small-radius tool breakage.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.27-33
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• 2008

This paper designs Shared Memory on the Dual Core system so that it operates a general System V IPC on the Linux O.S. Shared Memory is the technique that many processes can access to identical memory area. We treat Shared Memory which is SVR in a kernel step. We design a share memory facility of Linux operating system on the Dual Core System. In this paper the suggesting of share memory facility design plan in Dual Core system is enhance the performance in existing an unity processor system as a dual core practical use. We attemp a performance enhance in each CPU for each process which uses a share memory.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1448-1455
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• 2008

This paper designs Shared Memory on the Dual Core system so that it operates a general System V IPC on the Linux O.S. Shared Memory is the technique that many processes can access to identical memory area. We treat Shared Memory in this paper among big two branches of Shared Memory which are SVR in a kernel step format. We design a share memory facility of Linux operating system on the Dual Core System. In this paper the suggesting design plan of share memory facility in Dual Core system is enhancing the performance in existing unity processor system as a dual core practical use. We attempt a performance enhance in each CPU for each process which uses a share memory.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.503-510
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• 2002

In this paper, a general purpose embedded computer system is designed and implemented. The most crucial points of the system are extensibility and flexibility. The hardware of the developed system is composed of three modules and the software provides hardware independent application program interfaces. Moreover, uC/OS-II, a well-known open realtime kernel. is extended and ported onto the system. The extended uC/OS-II supports that multiple processes can have the same priority and such processes are scheduled in a round-robin manner.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.43-49
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• 2011

A distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, Zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome this problem clearly, this paper describes an improved backup protection coordination scheme using an IEC 61850-based distance relay for transformer backup protection. IEC 61850-based IED(Intelligent Electronic Device) and the network system based on the kernel 2.6 LINUX are realized to verify the proposed method. And laboratory tests to estimate the communication time show that the proposed coordination method is reliable enough for the improved backup protection scheme.

• Convergence Security Journal
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• v.7 no.4
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• pp.123-131
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• 2007

Recently, various threat and security incident are occurred for unspecified individuals, and this problem increases as the rapid of information sharing through Internet. The using of Information Security System such as IDS, Firewall, VPN etc. makes this problem minimal. However, professional knowledge or skill is needed in that case, normal user can't operate the Information Security System. This paper designs and implements File Access Control Module(FACM) to use easily for normal user against malicious threats and attacks. The FACM can exclude from malicious threats and attacks based on operation system rather than detection of threats and attacks. The FACM is working not only Windows System but also Linux System, and the FACM has effect on access control, integrity and non-repudiation for a file with an access control over files on the each OS that are used by multi-user.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.295-303
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• 2005

Recently, according to the rapid increase of Web users, various kinds of Web applications have been being developed. Hence, Web QoS(Quality of Service) becomes a critical issue in the Web services, such as e-commerce, Web hosting, etc. Nevertheless, most Web servers currently process various requests from Web users on a FIFO basis, which can not provide differentiated QoS. This paper presents a load balancing method to provide differentiated Web QoS in clustering web server. The first is the kernel-level approach, which is adding a real-time scheduling process to the operating system kernel to maintain the priority of user requests determined by the scheduling process of Web server. The second is the load-balancing approach, which uses IP-level masquerading and tunneling technology to improve reliability and response speed upon user requests. The third is the dynamic load-balancing approach, which uses the parameters related to the MIB-II of SNMP and the parameters related to load of the system such as memory and CPU.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1055-1061
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• 2004

In this research, a vision system for detecting breakages of small-diameter taps, which are rarely detected by the indirect in-process monitoring methods such as acoustic emission, cutting torque and motor current, was developed. Two HMI (Human Machine Interface) programs to embed the developed vision system into a Siemens open architecture controller, 840D, were developed. They are placed in sub-windows of the main window of the 840D and can be activated or deactivated either by a softkey on the operating panel or the M code in the NC part program. In the event that any type of tool breakage is detected, the HMI program issues a command for an automatic tool change or sends an alarm signal to the NC kernel. An evaluation test in a high-speed tapping machine showed that the developed vision system was successful in detecting breakages of small-diameter taps up to M1.

• Electronics and Telecommunications Trends
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• v.21 no.1 s.97
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• pp.1-13
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• 2006

임베디드 시스템이라 함은 우리가 생활하는 주변에서 흔히 접할 수 있고, 얘기만 들어도 쉽게 이해할 수 있는 PDA, 스마트폰, MP3 플레이어, 셋톱박스 등의 정보가전 기기들을 비롯하여 로봇, 텔레매틱스, 공장자동화, 군사기기와 센서노드에 이르는 디지털기기들에 컴퓨터가 내장되어 들어가 있는 시스템을 의미한다. 이러한 임베디드 시스템에 사용되는 임베디드 운영체제는 VxWorks, VRTX, pSOS, QNX와 같은 전용 RTOS에만 의존해 왔으나, 최근의 발전된 하드웨어와 네트워크 인프라로 인하여 보다 낮은비용으로 쉽고 빠르게 개발하며 범용으로 사용될 수 있는 임베디드 리눅스를 활용하는사례가 늘어나고 있는 추세에 있다. 이렇게 각광 받기 시작하는 임베디드 리눅스의 커널 기술과 관련한 대표적 관련 기술에 대해 설명한다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.448-453
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• 2003

This paper researched about technique of Opened CNC that were able to adapt themselves to rapid development of software and hardware. It is basic research what develop a scheme whereby technic make property. This paper theorized about to realize Opened CNC Software which is developing CNC Software flow from building Windows CE operating system's image that is possible realtime acting and multitasking. And Opened CNC Software's component designed independent classified modules. Classify Opened CNC Software's component which was consisted of basic OS Kernel, NC Code parser, Servo Motor Control, Software PLC, MMI(Man-Machine Interftce). And show there's functional example