• Journal of the Korean Magnetics Society
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• v.18 no.3
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• pp.89-93
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• 2008

Ferrimagnetic Copper-Iron-Chromium Oxide $CuFe_{0.9}Cr_{1.1}O_4$ has been investigated over a temperature range from liquid nitrogen temperature upto $N{\acute{e}}el$ temperature using the Mossbauer technique. Its $N{\acute{e}}el$ temperature is found to be 355 K. Above the $N{\acute{e}}el$ temperature the quadrupole splitting is found to be 0.50 mm/s. On the other hand, all the electric quadrupole shift values are zero below the $N{\acute{e}}el$ temperature within experimental error. These seemingly contradictory phenomena have been explained by the model that the magnetic hyperfine field is randomly oriented with respect to the principal axes of the electric-field-gradient tensor.

• Management & Information Systems Review
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• v.4
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• pp.257-284
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• 2000

According as the drivers increase who have their cars, the comprehensive studies on the automobile for the traffic safety have been raised as the important problems. Visual Recognition System for radio-controled driving is a part of the sensor processor of Unmanned Autonomous Vehicle System. When a driver drives his car on an unknown highway or general road, it produces a model from the successively inputted road traffic information. The suggested Recognition System of the Road Traffic Safety Information Board is to recognize and distinguish automatically a Road Traffic Safety Information Board as one of road traffic information. The whole processes of Recognition System of the Road Traffic Safety Information Board suggested in this study are as follows. We took the photographs of Road Traffic Safety Information Board with a digital camera in order to get an image and normalize bitmap image file with a size of $200{\times}200$ byte with Photo Shop 5.0. The existing True Color is made up the color data of sixteen million kinds. We changed it with 256 Color, because it has large capacity, and spend much time on calculating. We have practiced works of 30 times with erosion and dilation algorithm to remove unnecessary images. We drawing out original image with the Region Splitting Technique as a kind of segmentation. We made three kinds of grouping(Attention Information Board, Prohibit Information Board, and Introduction Information Board) by RYB( Red, Yellow, Blue) color segmentation. We minimized the image size of board, direction, and the influence of rounding. We also minimized the Influence according to position. and the brightness of light and darkness with Eigen Vector and Eigen Value. The data sampling this feature value appeared after building the learning Code Book Database. The suggested Recognition System of the Road Traffic Safety Information Board firstly distinguished three kinds of groups in the database of learning Code Book, and suggested in order to recognize after comparing and judging the board want to recognize within the same group with Nearest Neighborhood Decision Making.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.7-16
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• 1999

Stoichiometric and nonstoichiometric $Y_{3-x}Fe_{5+x}O_{12})$ polycrystalline samples (x=0.00, 0.05, 0.10, 0.30, -0.05, -0.10, -0.30) were prepared by solid state reaction method. The magnetic properties of the sample were investigated by FMR (ferromagnetic resonance) technique at microwave frequency 5.11 GHz (G-band) and 23.39 GHz (K-band) respectively. The spectroscopic splitting factor g were estimated to be 2.04~2.35 from the derivative absorption lines. As the samples became yttrium $(Y^{3+})$ excess and iron $(Fe^{3+})$ excess, Magnetizations were decreased. But resonance linewidth were increased. To investigate the anisotropy, the angular dependence of resonance magnetic fields were measured. Angular dependence of effective magnetizations were measured by FMR from 77 K to 300 K at K-band microwave frequency (23.39 GHz) and the saturation magnetizations were measured by VSM. The Bloch coefficients B and C were determined by fitting. $M_{eff}(0)$ was obtained by the extrapolation from 80 K. From this result, the spin wave stiffness constant D $(about\; 162~206 \;eV{\AA}^2)$and average square range of exchange interaction $$$(about \;5.84~12.13\;{\AA}^2)$ were determined.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2586-2594
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• 2009

A digital watermarking technique used as a protection and certifying mechanism of copyrighted creations including music, still images, and videos in terms of finding any loss in data, reproduction and pursuit. This study suggests using a selected geometric invariant point through the whole processing procedure of an image and inserting and extracting based on the invariant point so that it will be robust in a geometric transformation attack. The introduced algorithm here is based on a watershed splitting method in order to make medical images strong against RST(Rotation Scale, Translation) transformation and other processing. It also helps to maintain the watermark in images that are compressed and stored for a period of time. This algorithm also proved that is has robustness against not only JPEG compression attack, but also RST attack and filtering attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1315-1324
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• 2012

Security visualization is a form of the data visualization techniques in the field of network security by using security-related events so that it is quickly and easily to understand network traffic flow and security situation. In particular, the security visualization that detects the abnormal situation of network visualizing connections between two endpoints is a novel approach to detect unknown attack patterns and to reduce monitoring overhead in packets monitoring technique. However, the session-based visualization doesn't notice a difference between normal traffic and attacks that they are composed of similar connection pattern. Therefore, in this paper, we propose an efficient session-based visualization method for analyzing and detecting between normal server activities and attacks by using the IP address splitting and port attributes analysis. The proposed method can actually be used to detect and analyze the network security with the existing security tools because there is no dependence on other security monitoring methods. And also, it is helpful for network administrator to rapidly analyze the security status of managed network.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.199-202
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• 2023

Carriage return (CR) and line feed (LF), also known as CRLF injection is a type of vulnerability that allows a hacker to enter special characters into a web application, altering its operation or confusing the administrator. Log poisoning and HTTP response splitting are two prominent harmful uses of this technique. Additionally, CRLF injection can be used by an attacker to exploit other vulnerabilities, such as cross-site scripting (XSS). Email injection, also known as email header injection, is another way that can be used to modify the behavior of emails. The Open Web Application Security Project (OWASP) is an organization that studies vulnerabilities and ranks them based on their level of risk. According to OWASP, CRLF vulnerabilities are among the top 10 vulnerabilities and are a type of injection attack. Automated testing can help to quickly identify CRLF vulnerabilities, and is particularly useful for companies to test their applications before releasing them. However, CRLF vulnerabilities can also lead to the discovery of other high-risk vulnerabilities, and it fosters a better approach to mitigate CRLF vulnerabilities in the early stage and help secure applications against known vulnerabilities. Although there has been a significant amount of research on other types of injection attacks, such as Structure Query Language Injection (SQL Injection). There has been less research on CRLF vulnerabilities and how to detect them with automated testing. There is room for further research to be done on this subject matter in order to develop creative solutions to problems. It will also help to reduce false positive alerts by checking the header response of each request. Security automation is an important issue for companies trying to protect themselves against security threats. Automated alerts from security systems can provide a quicker and more accurate understanding of potential vulnerabilities and can help to reduce false positive alerts. Despite the extensive research on various types of vulnerabilities in web applications, CRLF vulnerabilities have only recently been included in the research. Utilizing automated testing as a recurring task can assist companies in receiving consistent updates about their systems and enhance their security.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.27-33
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• 2000

Purpose: To determine the electronic spin relaxation times, $T_{le}$, of three commercially available Gd-chelated MR contrast agents, Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA, using Electron Paramagnetic Resonance(EPR) technique. Material and Methods: The paramagnetic MR contrast agents, Gd-DTFA(Magnevist) , Gd-DTFA-BMA(OMNISCAN) and Gd-DOTA(Dotarem), were used for this study, The EPR spectra of these contrast agents, which were prepared 2:1 methanol/water solution, were obtained at low temperatures, from $-160^{\circ}C~20^{\circ}C$. The glassy-state EPR spectra for these contrast agents were then fitted by the simulation spectra generated with different zero-field splitting (ZFS) parameters by a computer simulation program 'GEN', which generates the EPR powder spectrum using a given ZFS in $3{\times}3$ tensor. Finally, the spin relaxation times of the contrast agents were then determined from the $T_{2e}$, D, and E values of the best simulation spectra using the McLachlan's theory of average relaxation rate. Results: The electronic transverse spin relaxation times, $T_{2e}'s$, of Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA were 0.113ns, 0.147ns and 1.81ns respectively. The g-values were 1.9737, 1.9735 and 1.9830 and the electronic spin relaxation times, $T_{1e}'s$, were 18.70ns, 33.40ns and $1.66{\mu}s$, respectively. Conclusion: The results of these studies reconfirm that the paramagnetic MR contrast agents with larger ZFS parameters should have shorter $T_{1e}'s$. Among three contrast agents used for this study, Gd-DOTA chelated with cyclic ligand structure shows better electronic property then the others with linear structure. Thus, it is concluded that the exact determination of ZFS parameters is the important factor in evaluating relaxation enhancement effect of the agents and in developing new contrast agents.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.165-171
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• 2008

Purpose: The purpose of this study was to introduce a new surgical technique and to evaluate the preliminary results after operative treatment with using TightRope$^{(R)}$ for treating acute acromioclavicular joint dislocation. Material and Methods: We studies 10 patients who were followed up for more than 6 months after operative treatment with using an TightRope$^{(R)}$. A longitudinal incision approximately 4cm in length was made from 1cm medial to the acromioclavicular joint to the coracoid process, and then coracocalvicular ligament augmentation using TightRope$^{(R)}$ was done after splitting the deltoid. For postoperative stability, two 1.6 mm Kirschner wires were inserted temporarily across the acromioclavicular joint in all cases. The radiologic results on the serial plain radiographs and the clinical results according to the UCLA score were analyzed. Results: Radiologically, 7 cases showed anatomical reduction, 2 cases showed a slightly loss of reduction and 1 case showed partial loss of reduction. Clinically, 6 cases were excellent, 3 cases were good and 1 case was fair. Conclusion: Coracoclavicular ligament augmentation using TightRope$^{(R)}$ for treating acute acromioclavicular joint dislocation is a minimally invasive, safe procedure that provides satisfactory radiologic and clinical preliminary results. Yet the long-term results have to be analyzed to determine the final results of this procedure.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.127-136
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• 2005

This paper measured a proper ratio of the size of demand fetch cache $L_1$ to that of prefetch cache $L_P$ by imulation when the size of $L_1$ and $L_P$ are constant which organize space-limited level 1 cache of a single microprocessor chip. The analysis of our experiment showed that in the condition of the sum of the size of $L_1$ and $L_P$ are 16 KB, the level 1 cache organization by constituting $L_P$ with 4 KB and employing OBL and FIFO as a prefetch technique and a cache replacement policy respectively resulted in the best performance. Also, this analysis showed that in the condition of the sum of the size of $L_1$ and $L_P$ are over 32 KB, employing dynamic filtering as prefetch technique of $L_P$ are more advantageous and splitting level 1 cache by constituting $L_1$ with 28 KB and $L_P$ with 4 KB in the case of 32 KB of space are available, by constituting $L_1$ with 48 KB and $L_P$ with 16 KB in the case of 64 KB elicited the best performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.9-16
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• 2006

Many image and video compression algorithms work by splitting the image into blocks and producing variable-length code bits for each block data. If variable-length code data are transmitted consecutively over error-prone channel without any error protection technique, the receiving decoder cannot decode the stream properly. So the standard image and video compression algorithms insert some redundant information into the stream to provide some protection against channel errors. One of redundancies is resynchronization marker, which enables the decoder to restart the decoding process from a known state in the event of transmission errors, but its usage should be restricted not to consume bandwidth too much. The Error Resilient Entropy Code(EREC) is well blown method which can regain synchronization without any redundant information. It can work with the overall prefix codes, which many image compression methods use. This paper proposes EREREC method to improve FEREC(Fast Error-Resilient Entropy Coding). It first calculates initial searching position according to bit lengths of consecutive blocks. Second, initial offset is decided using statistical distribution of long and short blocks, and initial offset can be adjusted to insure all offset sequence values can be used. The proposed EREREC algorithm can speed up the construction of FEREC slots, and can improve the compressed image quality in the event of transmission errors. The simulation result shows that the quality of transmitted image is enhanced about $0.3{\sim}3.5dB$ compared with the existing FEREC when random channel error happens.