• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.369-376
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• 2019

This paper studies desirable form of future e-government in terms of intelligent government research in response to new intelligent cyber security services in the fourth industrial revolution. Also, the strategic planning of the future e-government has been contemplated in terms of the centralization and intellectualization which are significant characteristics of the fourth industrial revolution. The new system construction which is applied with security analysis technology using big data through advanced relationship analysis is suggested in the paper. The establishment of the system, such as SIEM(Security Information & Event Management), which anticipatively detects security threat by using log information through big data analysis is suggested in the paper. Once the suggested system is materialized, it will be possible to expand big data object, allow centralization in terms of e-government security in the fourth industrial revolution, boost data process, speed and follow-up response, which allows the system to function anticipatively.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3051-3057
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• 2021

The concrete is considered as an important radiation shielding material employed widely in nuclear reactors, particle accelerators, laboratory hot cells and other different radiation sources. The present research is dedicated to the shielding properties study of the ordinary concrete reinforced with different weight fractions of lead oxide micro/nano particles. Lead oxide particles were fabricated by chemical synthesis method and their properties including the average size, morphological structure, functional groups and thermal properties were characterized by XRD, FESEM-EDS, FTIR and TGA analysis. The gamma ray mass attenuation coefficient of concrete composites has been calculated and measured by means of the Monte Carlo simulation and experimental methods. The simulation process was based on the use of MCNP Monte Carlo code where the mass attenuation coefficient (μ/ρ) has been calculated as a function of different particle sizes and filler weight fractions. The simulation results showed that the employment of the lead oxide filler particles enhances the mass attenuation coefficient of the ordinary concrete, drastically. On the other hand, there are approximately no differences between micro and nano sized particles. The mass attenuation coefficient was increased by increasing the weight fraction of nanoparticles. However, a semi-saturation effect was observed at concentrations more than 10 wt%. The experimental process was based on the fabrication of concrete slabs filled by different weight fractions of nano lead oxide particles. The mass attenuation coefficients of these slabs were determined at different gamma ray energies using ²²Na, ¹³⁷Cs and ⁶⁰Co sources and NaI (Tl) scintillation detector. The experimental results showed that the HVL parameter of the ordinary concrete reinforced with 5 wt% of nano PbO particles was reduced by 64% at 511 keV and 48% at 1332 keV. Reasonable agreement was obtained between simulation and experimental results and showed that the employment of nano PbO particles is more efficient at low gamma energies up to 1Mev. The proposed concrete is less toxic and could be prepared in block form instead of toxic lead blocks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.137-145
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• 2003

Nowadays, people can communicate with each other on any time at my place by development of wireless communications. But, the openness of mobile communications Poses serious security threats and the security is necessary on mobile communications to support the secure communication channel. The most commonly method is stream cipher for mobile communications. Generally, this stream cipher is implemented by LFSR(Linear Feedback Shift Register). On this paper proposes the modified mechanism of the S box is usually used in block cipher to advance security og the stream cipher and this mechanism is the modified three one in consideration og the randomness. Generally, S box that is function with nonlinear property makes data more strong by attack. The randomness test of the proposed algorithm is used Ent Pseudorandom Number Sequence Test Program and by the test result it proves that it has better randomness and serial correlation value than the based stream cipher on respective test.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.97-107
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• 2004

This paper presents an System-on-Chip(SoC) implementation of fingerprint feature extraction system. Typical fingerprint feature extraction systems employ binarization and thinning processes which cause many extraction errors for low qualify fingerprint images and degrade the accuracy of the entire fingerprint recognition system. To solve these problems, an algorithm directly following ridgelines without the binarization and thinning process has been proposed. However, the computational requirement of the algorithm makes it hard to implement it on SoCs by using software only. This paper presents an implementation of the ridge-following algorithm onto SoCs. The algorithm has been modified to increase the efficiency of hardwares. Each function block of the algorithm has been implemented in hardware or in software by considering its computational complexity, cost and utilization of the hardware, and efficiency of the entire system. The fingerprint feature extraction system has been developed as an IP for SoCs, hence it can be used on many kinds of SoCs for smart cards.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.115-126
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• 2005

SHACAL-2 is a 256-bit block cipher with up to 512 bits of key length based on the hash function SHA-2. It was submitted to the the NESSIE project and was recommended as one of the NESSIE selections. In this paper, we present two types of related-key attacks called the related-key differential-(non)linear and the related-key rectangle attacks, and we discuss the security of SHACAL-2 against these two types of attacks. Using the related-key differential-nonlinear attack, we can break SHACAL-2 with 512-bit keys up to 35 out of its 64 rounds, and using the related-key rectangle attack, we can break SHACAL-2 with 512-bit keys up to 37 rounds.

• Journal of Korea Multimedia Society
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• v.24 no.6
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• pp.768-788
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• 2021

The reversible data hiding technique safely transmits secret data to the recipient from malicious attacks by third parties. In addition, this technique can completely restore the image used as a transmission medium for secret data. The reversible data hiding schemes have been proposed in various forms, and recently, the reversible data hiding schemes based on interpolation are actively researching. The reversible data hiding scheme based on the interpolation method expands the original image into the cover image and embed secret data. However, the existing interpolation-based reversible data hiding schemes did not embed secret data during the interpolation process. To improve this problem, this paper proposes embedding the first secret data during the image interpolation process and embedding the second secret data into the interpolated cover image. In the embedding process, the original image is divided into blocks without duplicates, and the maximum and minimum values are determined within each block. Three way searching based on the maximum value and two way searching based on the minimum value are performed. And, image interpolation is performed while embedding the first secret data using the PVD scheme. A stego image is created by embedding the second secret data using the maximum difference value and log function in the interpolated cover image. As a result, the proposed scheme embeds secret data twice. In particular, it is possible to embed secret data even during the interpolation process of an image that did not previously embed secret data. Experimental results show that the proposed scheme can transmit more secret data to the receiver while maintaining the image quality similar to other interpolation-based reversible data hiding schemes.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.114-122
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• 2022

Objective : Early descent of the diaphragm sellae (DS) during endoscopic endonasal transsphenoidal surgery (EETS) for pituitary macroadenoma surgery is occasionally a troublesome event by blocking the surgical field. Here we introduce an alternative technique with the new pituitary retractor and present our clinical experiences. Methods : We designed a simple and rigid pituitary retractor with the least space occupation in the nasal cavity to be compatible in EETS. The pituitary retractor was held by external holder system to support the herniated DS stably. We retrospectively reviewed a clinical 22 cases of pituitary macroadenomas underwent EETS using the pituitary retractor. Results : The pituitary retractor stably pushed up the herniated DS in all cases, and the surgeon proceeded the procedure with bimanual maneuver. The pituitary retractor was helpful to remove tumors around the medial cavernous sinus and behind the DS in 16 and seven cases, respectively. In four cases, the meticulous hemostasis was completed with the direct visualization by the DS elevation with this retractor. Gross total tumor resection was performed in 20/22 patients (91%). The impaired visual function and hypopituitarism were improved in 18/20 (90%) and 7/14 (50%) patients after surgery, respectively. There was no complication related with the pituitary retractor. Conclusion : During EETS for pituitary macroadenomas, the novel pituitary retractor reported in this study is a very useful technique when the herniated DS block the surgical field and bimanual maneuver. This pituitary retractor can help to result in the excellent surgical outcomes with minimal morbidity.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.1-8
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• 2022

With the development of communication infrastructure, the number of network equipment owned by one person is gradually increasing. General-purpose devices such as smartphones can implement theft/loss prevention function by implementing S/W. However, other small devices lack practicality such as long-distance communication problems due to standard communication technology specifications or H/W limitations, and lack of functions(authentication and security). This study combines the Lora communication protocol in the LPWA standard environment and the blockchain technology. Anti-theft and security functions were added to the protocol, and the PBFT consensus algorithm was applied to build a blockchain network. As a result of the test, the effectiveness of safety(authentication and trust network) and performance(blockchain processing performance) were confirmed. This study aims to contribute to the future development of portable or small device anti-theft products as a 4th industrial convergence research.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.259-266
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• 2022

In this study, we developed a deep learning and vision sensor-based assembly performance evaluation method isfor prefabricated steel structures. The assembly parts were segmented using a modified version of the receptive field block convolution module inspired by the eccentric function of the human visual system. The quality of the assembly was evaluated by detecting the bolt holes in the segmented assembly part and calculating the bolt hole positions. To validate the performance of the evaluation, models of standard and defective assembly parts were produced using a 3D printer. The assembly part segmentation network was trained based on the 3D model images captured from a vision sensor. The sbolt hole positions in the segmented assembly image were calculated using image processing techniques, and the assembly performance evaluation using the k-nearest neighbor algorithm was verified. The experimental results show that the assembly parts were segmented with high precision, and the assembly performance based on the positions of the bolt holes in the detected assembly part was evaluated with a classification error of less than 5%.

• Korean Journal of Materials Research
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• v.32 no.8
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• pp.345-353
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• 2022

In this study, using deep learning, super-resolution images of transmission electron microscope (TEM) images were generated for nanomaterial analysis. 1169 paired images with 256 × 256 pixels (high resolution: HR) from TEM measurements and 32 × 32 pixels (low resolution: LR) produced using the python module openCV were trained with deep learning models. The TEM images were related to DyVO₄ nanomaterials synthesized by hydrothermal methods. Mean-absolute-error (MAE), peak-signal-to-noise-ratio (PSNR), and structural similarity (SSIM) were used as metrics to evaluate the performance of the models. First, a super-resolution image (SR) was obtained using the traditional interpolation method used in computer vision. In the SR image at low magnification, the shape of the nanomaterial improved. However, the SR images at medium and high magnification failed to show the characteristics of the lattice of the nanomaterials. Second, to obtain a SR image, the deep learning model includes a residual network which reduces the loss of spatial information in the convolutional process of obtaining a feature map. In the process of optimizing the deep learning model, it was confirmed that the performance of the model improved as the number of data increased. In addition, by optimizing the deep learning model using the loss function, including MAE and SSIM at the same time, improved results of the nanomaterial lattice in SR images were achieved at medium and high magnifications. The final proposed deep learning model used four residual blocks to obtain the characteristic map of the low-resolution image, and the super-resolution image was completed using Upsampling2D and the residual block three times.