• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1788-1792
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• 2006

The ordered weighted averaging (OWA) operator by Yager has received more and more attention since its appearance. One key point in the OWA operator is to determine its associated weights. Among numerous methods that have appeared in the literature, we notice the maximum entropy OWA (MEOWA) weights that are determined by taking into account two appealing measures characterizing the OWA weights. Instead of maximizing the entropy in the formulation for determining the MEOWA weights, the new method in the article tries to obtain the OWA weights which are evenly spread out around equal weights as much as possible while strictly satisfying the orness value provided in the program. This consideration leads to the least squared OWA (LSOWA) weighting method in which the program tries to obtain the weights that minimize the sum of deviations from the equal weights since entropy is maximized when the weights are equal. Above all, the LSOWA weights display symmetric allocations of weights on the basis of equal weights. The positive or negative allocations of weights from the median as a basis depend on the magnitude of orness specified. Further interval LSOWA weights are constructed when a decision-maker specifies his or her value of orness in uncertain numerical bounds.

• Structural Monitoring and Maintenance
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• v.3 no.2
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• pp.175-194
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• 2016

Based on the change of traditional viscoelastic damper structure, a brand-new damper is designed to control simultaneously the translational vibration and the rotational vibration for platforms. Experimental study has been carried out on the mechanical properties of viscoelastic material and on its multi-dimensional seismic response control effect of viscoelastic damper. Three types of viscoelastic dampers with different shapes of viscoelastic material are designed to test the influence of excited frequency, strain amplitude and ambient temperature on the mechanical property parameters such as circular dissipation per unit, equivalent stiffness, loss factor and storage shear modulus. Then, shaking table tests are done on a group of single-storey platform systems containing one symmetric platform and three asymmetric platforms with different eccentric forms. Experimental results show that the simulation precision of the restoring force model is rather good for the shear deformation of viscoelastic damper and is also satisfied for the torsion deformation and combined deformations of viscoelastic damper. The shaking table tests have verified that the new-type viscoelastic damper is capable of mitigating the multi-dimensional seismic response of offshore platform.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.418-421
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• 2001

The ceramic filters were developed using technology similar to that of quartz crystal and electromechanical filter. However, the key to this development involved the theoretical analysis of vibration modes and material improvements of piezoelectric ceramics. The primary application of ceramic filters has been for consumer-market use. Accordingly, a major emhpasis has involved mass production technology, leading to low-priced devices. A typical ceramic filter includes monolithic resonators and capacitors packaged in unique configurations. Nakazawa developed a double-mode resonator as two acoustically coupled single resonators. And he developed 10.7MHz crystal filters using multi-energy trapping mode of thickness shear vibration. He succeeded in realizing a two-pole band pass filter response without external inductance by splitting a dot electrode to creat coupled symmetric and antisymmetric vibration modes. Accordingly, the simulation for ceramic filter were important. So that, this paper were investigated the pass frequency of filter on the electrode length and thickness of ceramic.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.2
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• pp.41-49
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• 2016

Lossless encryption methods are more applicable than lossy encryption methods when marginal distortion is not tolerable. In this research, the author propose a novel lossless symmetric key encryption/decryption technique. In the proposed algorithm, the image is transformed into the frequency domain using the lifting wavelet transform, then the image sub-bands are encrypted in a such way that guarantees a secure, reliable, and an unbreakable form. The encryption involves scattering the distinguishable frequency data in the image using a reversible weighting factor amongst the rest of the frequencies. The algorithm is designed to shuffle and reverse the sign of each frequency in the transformed image before the image frequencies are transformed back to the pixel domain. The results show a total deviation in pixel values between the original and encrypted image. The decryption algorithm reverses the encryption process and restores the image to its original form. The proposed algorithm is evaluated using standard security and statistical methods; results show that the proposed work is resistant to most known attacks and more secure than other algorithms in the cryptography domain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1653-1660
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• 2010

The user information stored in database have been leaked frequently. To protect information against malevolent manager on the inside or outside aggressor, it is one of the most efficient way to encrypt information and store to database. It is better to destruct information than not to use encrypted information stored in database. The encrypted database search system is developed variously, and used widely in many fields. In this paper, we implemented the scheme that can search encrypted document without exposing user's information to the untrusted server in mobile device. We compared and analyzed the result embodied with DES, AES, and ARIA based on symmetric key by searching time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1065-1078
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• 2014

Considering the safety of the data and performance, it can be said that the performance of the AES algorithm in a symmetric key-based encryption is the best in the IPSec-based VPN. When using the AES algorithm in IPSec-based VPN even with the expensive hardware encryption card such as OCTEON Card series of Cavium Networks, the Performance of VPN works less than half of the firewall using the same hardware. In 2008, Intel announced a set of 7 AES-NI instructions in order to improve the performance of the AES algorithm on the Intel CPU. In this paper, we verify how much the performance IPSec-based VPN can be improved when using seven sets of AES-NI instruction of the Intel CPU.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.858-867
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• 2011

The RFID(Radio-Frequency IDentification) systems have many security problem such as eavesdropping, a replay attack, location tracking and DoS(Denial of Service) attacks. Because RFID systems use radio-frequency. So research are being made to solve the problem of RFID systems, one of which is AES algorithm. This paper presents an authentication protocol using AES and one-time random number to secure other attacks like eavesdropping, a replay attack, location tracking, In addtion, RSMAP uses OTP(One-Time Pad) in order to safely transmit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2860-2866
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• 1997

Kerberos is the most used example of authentication technology in distributed environment. In this paper, based on this method, a new authentication mechanism associated with X.509 protocol that authenticates services between regions is presented. Since any suggestions to regional services are not described in Kerberos, the authentication between regiona is performed via the connected chain obtained from x.509. These two protocols have distinguished key management systems -X.509 is designed using an asymmetric method, while Kerberos using a symmetric method. In order to provide regional services, X.509 is employed on connection part and Kerberos on actual authetication part.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.2
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• pp.49-59
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• 2018

Encryption of digital images has been requested various fields. In the meantime, many algorithms based on a text - based encryption algorithm have been proposed. In this paper, we propose a method of encryption in wavelet transform domain to utilize the characteristics of digital image. In particular, wavelet transform is used to reduce the association between the encrypted image and the original image. Wavelet packet transformations can be decomposed into more subband images than wavelet transform, and various position permutation, numerical transformation, and visual transformation are performed on the coefficients of this subband image. As a result, this paper proposes a method that satisfies the characteristics of high encryption strength than the conventional wavelet transform and reversibility. This method also satisfies the lossless symmetric key encryption and decryption algorithm. The performance of the proposed method is confirmed by visual and quantitative. Experimental results show that the visually encrypted image is seen as a completely different signal from the original image. We also confirmed that the proposed method shows lower values of cross correlation than conventional wavelet transform. And PSNR has a sufficiently high value in terms of decoding performance of the proposed method. In this paper, we also proposed that the degree of correlation of the encrypted image can be controlled by adjusting the number of wavelet transform steps according to the characteristics of the image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.584-586
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• 2017

In this paper we provide a unified crypto core that integrates lightweight symmetric cryptography and authentication. The crypto core implements a unified 128 bit key architecture of PRESENT encryption algorithm and a new lightweight encryption algorithm. The crypto core also consist of an authentication unit which neglects the use of hashing algorithms. Four algorithms are used for authentication which come from the Hopper-Blum (HB) and Hopper-Blum-Munilla-Penado (HB-MP) family of lightweight authentication algorithms: HB, HB+, HB-MP and HB-MP+. A unified architecture of these algorithms is implemented in this paper. The unified cryptosystem is designed using Verilog HDL, simulated with Modelsim SE and synthesized with Xilinx Design Suite 14.3. The crypto core synthesized to 1130 slices at 189Mhz frequency on Spartan6 FPGA device.