• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.363-374
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• 2004

In this paper, we propose an in-line mode NIDS using network processors(NPs) that achieve performance comparable to ASIC and flexibility comparable to general-purpose processors. Even if many networking applications using NPs have been proposed, we cannot find any NP applications to NIDS in the literature. The proposed NIDS supports packet payload inspection detecting attacks, as well as packet filtering and traffic metering. In particular, we separate the filtering and metering functions from the complicated and time-consuming operations of the deep packet inspection function using two-level searching scheme, thus we can improve the performance, stability, and scalability of In-line mode system. We also implement a proto-type based on a PC platform and the Agere PayloadPlus (APP) 2.5G NP solution, and present a payload inspection algorithm to apply APP NP.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.36-45
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• 2005

This paper addresses the application of motor current spectral analysis for the detection of rolling-element bearing damage in induction machines. We set the experimental test bed. They is composed of the normal condition bearing system, the abnormal rolling-element bearing system of 2 type induction motors with shaft deflection system by external force and a hole drilled through the outer race of the shaft end bearing of the four pole test motor. We have developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module is checking stator current The effects on the stator current spectrum are described and related frequencies are also determined. This is an important result in the formulation of a fault detection scheme that monitors the stator currents. We utilized the FFT(Fast Fourier Transform), Wavelet analysis and averaging signal pattern by inner product tool to analyze stator current components. Especially, the analyzed results by inner product clearly illustrate that the stator signature analysis can be used to identify the presence of a bearing fault.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1520-1530
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• 2005

As XML is recognized as a prevalent standard for document representation and exchange in the Internet, the need for security of XML becomes very important issue. Until now researches on XML security have been focused on confidentiality or integrity like encryption and digital signature technology. But, as XML data becomes more massive and complicated, it requires managerial security that decided access permit or deny by the authority oi user who is using the XML data. Thus it requires models and mechanisms enabling the specification and enforcement of access control policies for XML documents. In this paper, we suggest the new access control model and mechanism that separate XML documents by access level, assign roles to each user by applying Role Based Access Control (RBAC) and perform access control to specific documents by encrypting each section with roles. The method, we suggested, has an advantage that it does not need to update the whole keys used in encryption process by updating only the relations between appropriate secure layers.

• Journal of Internet of Things and Convergence
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• v.5 no.2
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• pp.21-26
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• 2019

Wisdom contents is made by an ordinary person and contains life tips helpful in general. As the existing copyright management systems are designed for the corporate or professional authors, it's not easy to use and requires high cost for the ordinary person to get the copyright. Blockchain based system can notarize the block of transactions without help of trustful third party such as existing copyright protection center. Thus, blockchain based copyright protection model is needed to protect the ordinary author's copyright. In this study, we propose the smart contract based copyright protection model which run on the blockchain network. The proposed model consists of smart contract creation, contents purchase and profit sharing stages. The digital signature scheme is used to get the contract agreed by the seller and the author. The smart contract stores the author information, contents information and the percentage of the share as states. If the contents is sold, the sales tokens are redistributed to the author and the seller according to the share. The proposed model can be applied to the ordinary person's copyright registration and management for Wisdom contents distributed in cafe, blog, YouTube, etc.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1439-1444
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• 2005

Induction motors are the most commonly used electrical drives because they are rugged, mechanically simple, adaptable to widely different operating conditions, and simple to control. The most common faults in squirrel-cage induction motors are bearing, stator and rotor faults. Surveys conducted by the IEEE and EPRI show that the most common fault in induction motor is bearing failure (${\sim}$40% of failure). Thence, this paper addresses experimental results for diagnosing faults with different rolling element bearing damage via motor current spectral analysis. Rolling element bearings generally consist of two rings, an inner and outer, between which a set of balls or rollers rotate in raceways. We set the experimental test bed to detect the rolling-element bearing misalignment of 3 type induction motors with normal condition bearing system, shaft deflection system by external force and a hole drilled through the outer race of the shaft end bearing of the four pole test motor. This paper takes the initial step of investigating the efficacy of current monitoring for bearing fault detection by incipient bearing failure. The failure modes are reviewed and the characteristics of bearing frequency associated with the physical construction of the bearings are defined. The effects on the stator current spectrum are described and related frequencies are also determined. This is an important result in the formulation of a fault detection scheme that monitors the stator currents. We utilized the FFT, Wavelet analysis and averaging signal pattern by inner product tool to analyze stator current components. The test results clearly illustrate that the stator signature can be used to identify the presence of a bearing fault.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.517-521
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• 2008

A worm is a malware that propagates quickly from host to host without any human intervention. Need of early worm detection has changed research paradigm from signature based worm detection to the behavioral based detection. To increase effectiveness of proposed solution, in this paper we present mechanism of detection and prevention of worm in distributed fashion. Furthermore, to minimize the worm destruction; upon worm detection we propagate the possible attack aleγt to neighboring nodes in secure and organized manner. Considering worm behavior, our proposed mechanism detects worm cycles and infection chains to detect the sudden change in network performance. And our model neither needs to maintain a huge database of signatures nor needs to have too much computing power, that is why it is very light and simple. So, our proposed scheme is suitable for the ubiquitous environment. Simulation results illustrate better detection and prevention which leads to the reduction of infection rate.

• Journal of Korea Multimedia Society
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• v.9 no.2
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• pp.215-225
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• 2006

Binary images, such as cartoon character images, text images and signature images, which consist of two values with black and white have more difficulties inserting imperceptible secret data than color images. Steganography using binary cover images is not easy to satisfy requirements for both the imperceptibility of stego images and a high embedding rate of secret data at the same time. In this paper, we propose a scheme that can get both the high quality of stego images and a high embedding rate by supplementing the advantages of previous research. In addition, the insertion of the proposed method changes only existing pixels of the imperceptible position and can embed the secret data of [$log_2(mn+1)-2$] bits in a block with size of $m{\times}n$.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.6
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• pp.83-92
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• 2009

Ari Juels proposed Yoking-Proof protocol for authenticating multiple tags simultaneously using RFID system. Because common Yoking-Proof methods authenticate by using MAC (Message Authentication Code), it is difficult to apply them to inexpensive tags. It is also difficult to implement common hash functions such as MD5 in inexpensive tags. So, Ari Juels also proposed a lightweighted Yoking-Proof method with only 1 authentication. However, Minimalist MAC, which is a lightweighted MAC used in the proposed method is for single-use, and the proposed structure is vulnerable to replay attacks. Therefore, in this study, the minimalist MAC using Lamport's digital signature scheme was adopted, and a new type of Yoking-Proof protocol was proposed where it uses tags that are safe from replay attacks while being able to save multiple key values.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.284-287
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• 2000

Recently, developing medical devices have a tendency becoming the module for satisfying user's mutual complex needs. Because the most effective method for the observation of patients condition a diagnosis and a treatment is collecting data from various devices and controling operation following it. Module tendency is more popular due to manage easily totally many individual systems. This study implemented communication protocol to control by one control system connecting modular medical devices. Implemented system consist of one master module controlling all module and managing communication and many Slave modules. Communication between each modules introduced SPI(Serial Peripheral Interface) among many synchronous serial communication methods for the exact transmission and receipt of data. All communication executes by packet format. This can detect error. And, this protocol introduced PNP(Plug And Play) function that auto-detect connecting or removing module during running. This protocol exactly transmitted and received in faster speed more than 1Mbps. And in practical application to the ventilator this confirmed to give and take real-time data. And various functions by th central control system is implemented in this protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.43-49
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• 2000

That modem society is an information society, information society has placed a high value on information and knowledge. Therefore, modem civilization depends largely on information and knowlege so the most valuable sources of all intelligence activities. This paper was studied on the new developmental direction for intelligent network service. The results of this study is as follow: first, intelligent network service must be systematic development. Second, intelligent network service must be promoted, presenting the development and establishment direction in future society. Third, intelligent network service must be able to unify ail the networks. Fourth, intelligent network service must be development for customers. Fifth, the cost of intelligent network service is determined by Telecommunication Reguration Commission. Sixth, the number system of intelligent network service must be accomplished by number system for future