• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.531-534
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• 2022

승차 공유, 카풀, 렌터카의 이용률이 증가하면서 많은 사용자가 동일한 차량에 로컬 액세스 할 수 있는 시나리오가 더욱 보편화됨에 따라 차량 네트워크에 대한 공격 가능성이 커지고 있다. 차량용 CAN Bus Network에 대한 DoS(Denial of Service), Fuzzy Attack 및 Replay Attack과 같은 공격은 일부 ECU(Electronic Controller Unit) 비활성 및 작동 불능 상태를 유발한다. 에어백, 제동 시스템과 같은 필수 시스템이 작동 불가 상태가 되어 운전자에게 치명적인 결과를 초래할 수 있다. 차량 네트워크 침입 탐지를 위하여 많은 연구가 진행되고 있으나, 기존 화이트리스트를 이용한 탐지 방법은 새로운 유형의 공격이 발생하거나 희소성이 높은 공격일 때 탐지하기 어렵다. 본 논문에서는 인공신경망 기반의 CAN 버스 네트워크 침입 탐지 기법을 제안한다. 제안하는 침입 탐지 기법은 2단계로 나누어 진다. 1단계에서 정상 패킷 분포를 학습한 VAE 모형이 이상 탐지를 수행한다. 이상 패킷으로 판정될 경우, 2단계에서 인코더로부터 추출된 잠재변수와 VAE의 재구성 오차를 이용하여 공격 유형을 분류한다. 분류 결과의 신뢰점수(Confidence score)가 임계치보다 낮을 경우 학습하지 않은 공격으로 판단한다. 본 연구 결과물은 정보보호 연구·개발 데이터 첼린지 2019 대회의 차량 이상징후 탐지 트랙에서 제공하는 정상 및 3종의 차량 공격시도 패킷 데이터를 대상으로 성능을 평가하였다. 실험을 통해 자동차 제조사의 규칙이나 정책을 사전에 정의하지 않더라도 낮은 오탐율로 비정상 패킷을 탐지해 낼 수 있음을 확인할 수 있다.

• Journal of IKEEE
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• v.23 no.3
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• pp.1096-1099
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• 2019

In this paper, we propose the protocol for construction of smart factory. The proposed protocol for construction of smart factory consists of an OPC UA Server/Client, a technology of TSN realtime communication, a NTP & PTP time synchronization protocol, a FieldBus protocol and conversion module, a technology of saving data for data transmit latency and synchronization protocol. OPC UA server/client is a system integration protocol which makes interface industrial hardware device and supports standardization which allows in all around area and also in not independent from any platform. A technology of TSN realtime communication provides an high sensitive time management and control technology in a way of sharing specific time between devices in the field of high speed network. NTP & PTP time synchronization protocol supports IEEE1588 standardization. A fieldbus protocol and conversion module provide an extendable connectivity by converting industrial protocol to OPC. A technology of saving data for data transmit latency and synchronization protocol provide a resolution function for a loss and latency of data. Results from testing agencies to assess the performance of proposed protocol for construction of smart factory, response time was 0.1367ms, synchronization time was 0.404ms, quantity of concurrent access was 100ea, quantity of interacting protocol was 5ea, data saving and synchronization was 1,000 nodes. It produced the same result as the world's highest level.

• Journal of Korean Society of Transportation
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• v.34 no.1
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• pp.81-94
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• 2016

The Korean real-time traffic responsive control systems, Cycle Offset Split Model of Seoul (COSMOS), employs a single theoretical model to estimate the degree-of-saturation (DS) on approaches. However, the deployment of the system has been accomplished without practical consideration of its field performance. This paper delivers a diagnosis study performed to find the relationships yet known on the DS values against the operational conditions unproved in theory but ordinarily observed in field practice. Based on the analysis of the historical log data (476,505 cycles) obtained from the COSMOS server, it was found; (1) full coverage of lane detections should perform better than the sample coverage of detection in ordinary conditions, (2) the sample coverage of detection perform better than the other case with an exclusive bus lane, (3) detection in which a shared lane is involved provide poor estimation of DS, (4) poor DS estimation when a detection lane is adjacent to a shared lane, and (5) the DS values obtained during a day can hardly be stable all time. The findings suggest traffic engineers a progressive direction to move forward for the next real-time traffic control systems.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.313-320
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• 2010

Preparing for the rapidly increment of air traffic volume of the 21st century, International Civi1 Aviation Organization(ICAO) started for studying a newly developed CNS/ATM System from the 1980s and after 2010, expect that the existing aeronautical facility is overloaded because air traffic volume increase rapidly. For this reason new CNS/ATM System will be the international standard system in the future. Especially, ADS-B(Automatic Dependent Surveillance-Broadcast) as the key component of Surveillance and ATM in new CNS/ATM System provides the real-time and same air traffic information to pilots in the aircraft cockpit, air traffic controllers on the ground and surface vehicles at the same time. Information provided is displayed precisely and accurately through Multi-Function Display(MFD). We implement the MFD system being supporting for new CNS/ATM System. And we show the good performance of MFD system in labortory environment using the MIL-STD-1553B data bus.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.3
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• pp.69-75
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• 2011

In this paper, we propose an anycast event driven synchronization mechanism to reduce power overheads. Our proposed mechanism can reduce unnecessary polling operations on SHI(Snoop Hit Invalidate) or SHR(Snoop Hit Read) states. It prevents waisting bandwidth and reduces power overheads on polling operation. Also it decreases transition power of state change compared to broadcast model. Simulation results indicated that the proposed architecture had about 15.3% of power decrease compared to spin-lock model and about 4.7% of power decrease compared to broadcast model. Overall results indicated that proposed synchronization mechanism could increase power efficiency of multi-core system by reducing power overheads.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.10 s.352
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• pp.140-150
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• 2006

In this paper, we present a new hardware architecture for testing various cores embedded in SoC. The conventional solutions need much testing time since only one core is tested at single test period. To enhance this, S-TAM, a novel test architecture, and its controller which enable parallel testing of various cores are proposed. S-TAM supports bus sharing to broadcast testing and cores to be tested are selected by using it. In addition, S-TAM controller enables the effective SoC test by simultaneous controlling the various test cores which are based on the different test architectures like IEEE 1149.1 and IEEE 1500.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.244-253
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• 2000

Since no single routing-switching combination performs the best under various different types of applications, a flexible network is required to support a range of polices. This paper introduces an implementation of a look-up table routing engine offering flexible routing and switching polices without performance degradation unlike those based on microprocessors. By deciding contents of look-up tables, the engine can implement wormhole routing, virtual cut-through routing, and packet switching, as well as hybrid switching, under a variety of routing algorithms. Since the routing engine has a piplelined look-up table architecture, the routing delay is as small as one flit, and thus it can overlap multiple routing actions without performance degradation in comparison with hardwired routers dedicated to a specific policy. Because four pipeline stages do not induce a hazard, expensive forwarding logic is not required. The routing engine can accommodate four physical links with a time shared cut-through bus or single link with a cross-bar switch. It is implemented using Xilinx 4000 series FPGA.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.1
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• pp.9-14
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• 2003

APON, the subscriber network using bus or tree topology, requires MAC protocol, because it shares the uplink channel for many subscribers to transmit data to OLT. Although various MAC schemes, which consider each QoS characteristics of traffic are proposed considering transmission characteristics of ATM traffic class, existing schemes reduce the network efficiency by increasing transmission overhead in frame. In this paper, we propose new MAC scheme, which shows similar performance as those of existing schemes but does not increase transmission overhead. To prevent increasing transmission overhead, the proposed scheme encodes the information about each cell information of traffic of the local queue in RAU transmitted periodically from ONU to OLT Thus, the proposed MAC scheme shows similar performance as those of existing ones and increases efficiency of entire network.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.77-85
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• 2003

The conversion into a new Local Area Network (LAN) environment without clear analysis of the problems with the conventional LAN environment nay bring about some improvement of performance, but in general, the result would not be as good as expected. Besides, in case new traffic or application programs are added In the near future, traffic overload similar to the past may incur. Therefore, the conversion into a new LAN environment should not only relieve the problems with the conventional environment but also be able to cope with future expansion of the network flexibly. In the present paper, in view of the above, the problems with protocols and traffic that may occur in the Bus-structured 10/100 Mbps shared Ethernet that has been widely used by many institutions are reviewed, and as a case study whether such conversion into a new LAN environment in order to increase the efficiency in the operation, management, and utilization of the network would be proper for the actual operational environment is implemented, and the results are analyzed.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.157-165
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• 2006

This paper proposes a new output-buffered multicast ATM switch with tandem crosspoints switching fabric, named the MTCOS(Multicast Tandem Crosspoint Output-buffered Switch). The MTCOS consists of multiple simple crosspoint switch fabrics, named TCSF(Tandem Crosspoint Switch Fabric) , and concentrated output buffers for efficient multicasting. The TCSF resolves the cell delay deviation problem which the self-routing crossbar switches inherently have. Further, it offers multiple concurrent pathes from one input to multiple output ports. It also provides multi-channel switching by easy software configuration and has several desirable characteristics such as scalability, high Performance, and modularity. A shared traffic concentration and output queuing strategies of the MTCOS results in lower cell loss as well as lower cell delay time over a wide range of multicast traffic. Furthermore, it has lower hardware complexity than that of the SCOQ and Knockout multicast switch to achieve the same Knockout concentration rate as the conventional switches. It is shown that the proposed switch can be easily applied to design high performance for any multicast traffic by analytic analysis and computer simulation.