• The KIPS Transactions:PartC
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• v.8C no.4
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• pp.389-396
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• 2001

기존의 라우터 기반의 패킷 스크리닝 방식은 ATM 네트워크 상에서는 패킷 수준의 스크리닝 기능의 적용을 위하여 SAR(Segmentation And Reassembly) 과정을 필요로 하기 때문에 고속의 셀 처리를 수행하는 ATM Switch의 셀 처리 속도를 저하시킨다는 문제점을 안고 있다. 본 논문에서는 셀 스크리닝 방식에 기반한 병렬 처리 구조의 ATM Firewall Switch를 제안한다. 제안된 Enhanced ATM Firewall Switch는 셀 단위로 분할된 패킷의 1, 2번 셀들에 대한 검사만을 통하여 스크리닝 기능을 수행하기 때문에 셀 단위의 스크리닝 수행이 가능하며, 정책 캐쉬의 도입을 통해 셀 스크리닝 수행속도를 향상하였다. 또한 독립적인 User Cells Filter 기능 블록의 설계를 통하여 병렬 처리 구조의 셀 스크리닝 수행이 가능하도록 구성하여 셀 지연 시간을 최소화하였다.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.9-14
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• 1997

Check valves used in industrial and Nuclear Power Plant safety systems are susceptible to failure modes generally associated with wear of internal parts. Specifically, hinge pins, disc studs, pistons, and other mechanical parts may degrade over time, and in some cases, may which might produce a disabling event leading to plant or process shutdown. The primary diagnostic technique in the past has been to disassemble the valves. This procedure is costly, time consuming, and in the nuclear industry, it can lead to radiation exposure in some situations. Additionally repair and reassembly of a valve does not ensure proper operation. Non-intrusive diagnostic technologies including acoustics and magnetics with a digital signal analysis allow to evaluate check valve performance without a disassembly and is able to help the user detect degraded valve conditions.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.261-264
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• 2001

In this paper, we design IP of ATM AAL layer for B-ISDN. The designed ATM AAL module supports the function for AAL type 0, AAL type 3/4, AAL type 5. The designed IP provides for automatic CRC-32 and CRC-10 for AAL type and AAL type 3/4. Also our IP inserts and extracts the header and trailer for each type automatically. After HDL description, it is verified by the simulation. The designed U is implemented in Xilinx FPGA. Rx AAL module operates at 35MHz and Rx AAL module operates at 50MHz. The designed IP can be applicable in high-speed ATM SAR(Segmentation and Reassembly) chip.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.98-109
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• 2012

Recently, the optimisation of end-of-life (EOL) product remanufacturing processes has been highlighted. In particular, computer remanufacturing becomes important as the amount of disposed of computers is rapidly increasing. At the computer remanufacturing, depending on the selections of used computer parts, the value of remanufactured computers will be different. Hence, it is important to select appropriate computer parts at the reassembly. To this end, this study deals with a decision making problem to select the best combination of computer parts for minimising the total remanufacturing computer cost. This problem is formulated with an integer nonlinear programming model and heuristic search algorithms are proposed to resolve it.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.1-8
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• 2013

Remanufacturing of automobile parts is important for increasing the recycling resources. ECU(Electronic Control Unit) systems are becoming an increasingly important part of an automobile. But production company are reported in the ECU remanufacturing industry of domestic automobile parts due to a lack of remanufacturing technology and marketability. This paper introduces the ECU of remanufacturing, also grasps the structure and the analyzes failure cause that is external factors and fault in the characteristic design and steps in the Independent ECU remanufacturing process. The ECU manufacturing industry of the US was examined. The results in this paper could be used as the system information for further remanufacturing industry of domestic automobile parts.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.59-66
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• 2018

Data Distribution Service(DDS) provides the communications service programmers need to distribute time-critical data between embedded and/or enterprise devices or nodes. In this paper, I propose efficient methods for transmitting and receiving messages of various characteristics in real-time using DDS middleware. For high-frequency characteristic data, I describe several DDS packet types and various default and extended DDS QoS policies. In particular, the batching method is probably the best solution when considering several performance aspects. For large-capacity characteristic data. I will show a method using extended DDS QoS policies, a segmentation and reassembly method, and transmitting and receiving a large-capacity data with low priority method considering network conditions. Finally, I simulate and compare the result of performance for each methods. This results will help determine efficient methods for transmitting and receiving messages of various characteristics using DDS middleware.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.466-474
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• 2007

Asymmetric networks that the downlink bandwidth is larger than the uplink bandwidth may cause the degradation of the TCP performance due to the uplink congestion. In order to solve this problem, this paper designs and implements the Dynamic Segment Size Control mechanism which offers a suitable segment size for current networks. The proposed mechanism does not require any changes in customer premises but suppress the number of ACKs using segment reassembly technique to avoid the uplink congestion. The gateway which adapted the Dynamic Segment Size Control mechanism, detects the uplink congestion condition and dynamically measures the bandwidth asymmetric ratio and the packet loss ratio. The gateway reassembles some of segments received from the server into a large segment and transmits it to the client. This reduces the number of corresponding ACKs. In this mechanism, the SACK option is used when occurs the bit error during the transmission. Based on the simulation in the GEO satellite network environment, we analyzed the performance of the Dynamic Segment Size Control mechanism.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.443-449
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• 2014

To check the characteristics of nuclear fuels during an irradiation test, the nuclear fuel rod needs to be disassembled from the test rig located in the pool of the research reactor. Then, the disassembled fuel rod is delivered to the hot cell for intermediate examination. A fuel rod that passes the intermediate examination is delivered to the reactor pool to be reassembled into the test rig. The irradiation test is resumed with the reassembled test rig. Because nuclear fuel rods irradiated by neutrons are highly radioactive, all the disassembly and reassembly processes should be carried out in the pool of the research reactor to prevent operators being exposed to radiation. In particular, because a test rig is 5.4-m long and the reactor pool of HANARO is 6-m deep, special tools need to be developed for performing the disassembly and reassembly processes. In this study, a new assembly design of nuclear fuel rods for intermediate examination is introduced. Furthermore, tools for treating the irradiated fuel rod assembly are introduced, and their performance is verified by an out pile test.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3108-3115
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• 1999

Frame relay needs UPC function for the multiplexed logical connections to prevent malicious user traffic from incoming to network, to guarantee the QoS of conformed user traffic, and to protect the normal operation of network system. On the FR/ATM interworking in ATM networks, the UPC may be conducted either by cell-based ATM UPC or frame-based FR UPC. Frames come into and traverse ATm networks by segmentation to ATM cells. Of course, FR QoS should be guaranteed in spite of segmentation and reassembly in ATM networks. In this paper, we compared the QoS of cell-based ATM UPC and frame-based FR UPC in terms of analysis and simulation in case of ingress of excess traffic over negotiated traffic parameters at user-to-network interface. Also we studied frame-based UPC schemes including window-based FR UPC and frame-based VSA which is an ATM UPC algorithm recommended by ITU-T. We described introductions to frame relay including frame structure and FR/ATM interworking, FR traffic parameters and their relationship, comparison of FR QoS between frame-based FR UPC and cell-based ATM UPC, comparison of FR UPC schemes, necessities of egress traffic control, and conclusions.

• IE interfaces
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• v.15 no.2
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• pp.152-158
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• 2002

The explosive growth of the internet traffic in the last few years has imposed tremendous stress on today's routers, particularly in the core network. Recently, ATM LSRs(Label Switching Router) are potentially capable of providing the highest forwarding capacity in the backbone Internet network. VC merging is a mechanism in an ATM LSR that allows many IP routes to be mapped to the same VC label, and provides a scalable mapping method that can support thousands of destinations. VC merging requires reassembly buffers so that cells belonging to different packets intended for the same destination do not interleave with each other. In this study, we propose an architecture of the ATM LSR which supports VC merging. We propose traffic control scheme called APD(Active Packet Discard) algorithm so that predicts and controls the congestion of the Internet traffic effectively. We study the performance of this algorithm using simulation.