• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.127-135
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• 2017

Recently, the most brand new vehicles contain a lot of ECU for comfortable and safety driving environments. For efficient communication network among ECUs, almost car manufactures use CAN protocol which enables to decrease the number of communication lines dramatically and ensures higher data transmission reliability. However, CAN dose not ensure authentication of CAN data frame. So it is vulnerable to replay-attack on CAN data frame. This paper proposes the practical message authentication technique for In-vehicle CAN. To transmit data and MAC together, it is very useful to use the short length of MAC after considering limited space of CAN data frame. However to ensure safety of MAC, additional technique is required. We suggested a message authentication technique that can be usefully applied to build a safety network inside the vehicle because it considers limited data payload of CAN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.31-36
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• 2004

In this paper, we proposed the new structure of the Rake Finger using Walsh Switch, the shared accumulator, and the pipeline-FWHT algorithm for reducing the signal processing complexity resulting from the increase of the number of data correlator. The function simulation of the proposed architecture is performed by Synopsys tool and the timing simulation is performed by Compass tool. The number of computational operation in the proposed data correlators is 160 additions and the conventional ones is 512 additions when the number of walsh code N=4. As a result, it is reduced about 3.2 times other than the number of computational operation of the conventional ones. Also, the result shows that the data processing time of the proposed Rake Finger architecture is 90,496[ns] and the conventional ones is 110,696[ns]. It is $18.3\%$ faster than the data processing time of the conventional Rake Finger architecture.

• Convergence Security Journal
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• v.12 no.6
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• pp.61-67
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• 2012

Accordingly the number of smart-phone-based malicious codes is also increasing and their techniques for malicio us purpose are getting more clever and evolved. Among them, the malicious codes related to Android take the major portion and it can be estimated that they are based on open source so that the access to the system is easy. Intent is a technique to support the communication between application's components by transmitting message subjects in Android. Intent provides convenience to developers, but it can be utilized as security vulnerability that allows the developer with a malicious purpose to control the system as intended. The vulnerability of intent security is that personal information can be accessed using discretionally its proper function given to application and smart phone's functions can be maliciously controlled. This paper improves with the Intent security vulnerability caused by the smart phone users' discretional use of custom kernel. Lastly, it verifies the malicious behaviors in the process of installing an application and suggests a technique to watch the Intent security vulnerability in realtime after its installation.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.39-47
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• 2005

This paper proposes and analyzes the MAC(Message Authentication Code) algorithm that is used for the transition integrity and the entity authentication of message. The MAC algorithm uses the DES algorithm which has 64-bit block and 56-bit key and we compare the security according to 64-bit and 32-bit length of MAC value. Moreover, we use the SEED algorithm which has 128-bit block and 128-bit key and compare the security according to 128-bit and 64-bit length of MAC value. We analyze the security the forgery attack according to length of message and length of MAC value. this paper, a coarse-to-fine optical flow detection method is proposed. Provided that optical flow gives reliable approximation to two-dimensional image motion, it can be used to recover the three-dimensional motion. but usually to get the reliable optical flows are difficult. The proposed algorithm uses Horn's algorithm (or detecting initial optical flow, then Thin Plate Spline is introduced to warp a image frame of the initial optical flow to the next image frame. The optical flow for the warped image frame is again used iteratively until the mean square error between two image sequence frames is lowered. The proposed method is experimented for the real moving Picture image sequence. The proposed algorithm gives dense optical flow vectors.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.54-59
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• 2012

Multiple antenna transmission and reception, whose principal merits are significant increase in spectral efficiency and/or reduction in error rate, lose much of their effectiveness in high levels of interference from other cells. Incorporating the other cell interference into advanced signal processing at transmitter and receiver is one of the key challenges for cell boundary users in cellular system. Since receiver can obtain exact knowledge of interference channels more easily than transmitter, an interference-aware multiple antenna receiver that can significantly attenuate interferences is considered. Based on the receiver, codebook-based coordinated precoding schemes are proposed. According to the level of cooperation, centralized and distributed schemes are proposed. We verified by the simulation results that even the distributed schemes, which have same amount of feedback and no cooperation between cells, have performance gain compared to the conventional non-coordinated scheme.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1224-1230
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• 2006

In this paper, for spatial multiplexing with limited feedback, a precoding scheme is proposed based on the joint use of minimal instantaneous feedback and long-term feedback of a small number of bits, wherein the long-term feedback is used to convey a selected preceding matrix within a precodercodebook consisting of a number of unitary matrices, and the active column vectors of the selected unitary matrix are conveyed to the transmitter using instantaneous feedback. Focusing on the case of dual multi-input multi-output(MIMO) systems, precoder codebook design for maximizing the average throughput of a spatial multiplexing system with a zero-forcing(ZF) receiver is proposed. It is shown that the proposed scheme provides a considerable throughput enhancement over multi-mode antenna selection and multi-mode basis selection only with the additional long-yterm feedback of a small number of bits. For example, the throughput increases by 11.5 % than antenna selection and 5.1% than basis selection, respectively, when SNR=20 dB.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1445-1454
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• 2006

To compress a specific part of an image with high quality or to transfer it, JPEG2000 standard offers an ROI(Region-of-Interest) image coding method. What is important in ROI coding is to process relative importance between ROI and background and to process ROI mask. We propose an adaptive ROI coding method supplemented the existing Implicit ROI coding and Modified implicit ROI coding to improve image quality and reduce ROI mask information. The proposed method is an EBCOT-based ROI coding that extracts ROI from the compressed bitstream, and gets the ROI mask information by classifying the codeblocks into 6 patterns. The information includes the pattern type(3bit) and the width(5bit) expressing the boundary between two regions for each codeblock. As a result, the method shows an excellent compression performance in ROI region as well as in the whole region of an image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9C
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• pp.652-660
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• 2008

Applications running under embedded systems require various device drivers designed for different types and versions of the OS to manage resources effectively. In this paper, an automated device driver generator system which can generate the device drivers to be used in newer versions the target OS is proposed. In the proposed system, the structures of device drivers of specific OS are designed in the templates and stored in a library, and the target device drivers are generated by adding codes to the stored templates. Once device drivers are generated, they are registered into the kernel. The experimental results show that data transfer time has been slightly increased when compared against manually created drivers for TFT-LCD driver, USB interface keyboard/mouse driver, and AC'97 controller drivers. The code size for the generated drivers after compilation has also been increased slightly when compared with manually designed device drivers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5C
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• pp.382-390
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• 2005

Huffman codes are widely used for image and video data transmission. As the increase of real-time data, a lot of studies on effective decoding algorithms and architectures have been done. In this paper, we proposed a balanced binary search tree for Huffman decoding and compared the performance of the proposed architecture with that of previous works. Based on definitions of the comparison of codewords with different lengths, the proposed architecture constructs a balanced binary tree which does not include empty internal nodes, and hence it is very efficient in the memory requirement. Performance evaluation results using actual image data show that the proposed architecture requires small number of table entries, and the decoding time is 1, 5, and 2.41 memory accesses in minimum, maximum, and average, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.132-139
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• 2012

In 2011, Woosik Bae proposed a NLMAP(New Low-cost Mutual Authentication Protocol) in RFID based on hash function. They argued that minimize computation such as random number generation. In addition, NLMAP is safe against replay attack, spoofing attack, traffic analysis and eavesdropping attack due to using mutual authentication. So, when applied to RFID system has advantage such as providing a high level of security at a lower manufacturing cost. However, unlike their argue, attacker can obtain Tag's hash computed unique identification information. This paper proves possible the location tracking and spoofing attack using H(IDt) by attacker. In addition, we propose the improved a mutual authentication protocol in RFID based on hash function and CRC code. Also, our protocol is secure against various attacks and suitable for efficient RFID systems better than NLMAP.