• The KIPS Transactions:PartC
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• v.18C no.2
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• pp.61-70
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• 2011

Even though internet community is becoming the basic communication tool with rapidly changing internet environment, its damage is on the rise due to increasing spam messages of unspecified individuals. Currently, various methods to block spam mails, but studies on block spam messages from being automatically posted in community are still insufficient. This study suggested methods to block spam messages in internet community by collecting spam messages posted in internet community to analyze characteristics and frequencies of the messages and create block regulations. It collects spam messages of all messages saved in database of internet community, analyze the collected messages to create normalized rules that can define spam messages, and inspect spam messages among posted messages by using the regulations to block them. The suggested method has a structure that can block various types of spam messages by using information of spam messages collected and flexibly deal with changing spam message types.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.87-97
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• 2008

This research focused on development and application feasibility for the coalesced continuous block system in river bank protection. Most of block systems in river bank are pre cast type and have some difficulties against high velocity flood condition or high pressure load, however, the continuous block system can be applied to flood damage recover as well as environmental vegetation block system in river bank. For the application review and analysis of hydraulic condition for this block system, hydraulic physical modeling was carried out. The physical model was built as a scale of 1:50 by Froude similitude measuring the water levels and the water velocities for vegetation application or not. In consequence, the water velocities were observed to decrease meanly 10.1%, and the water depths were to increase meanly 17.8% in case of the of design flood, $Q=200m^3/sec$. To verify the hydraulic physical modeling, the numerical modeling should be conducted for a close examination of vegetation application by one or two dimensional numerical analysis as a next study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.379-387
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• 2012

This study investigates free vibration characteristics of new energy harvesting multi-layer block structures with different geometrical shapes using solid and shell finite elements and evaluate their piezoelectric effect on experiments. The two and three-dimensional finite element (FE) delamination models for block structures described in this paper is attractive not only because it shows excellent accuracy in analysis but also it shows the entire vibration mode shape. The FE model using ABAQUS is used for studying free vibrations of multi-layer block structures for various tip mass and PZT. In particular, new results reported in this paper are focused on the significant effects of the global and local vibration modes for various parameters, such as size of block shape, existence of tip mass and hole, and location of tip mass and PZT. In addition, we evaluate the power generation capacity of developed energy block structures through a laboratory-scale experiment.

• The Korean Journal of Pain
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• v.37 no.1
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• pp.59-72
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• 2024

Background: This study assessed the postoperative analgesic efficacy and safety of the quadratus lumborum block (QLB) in pediatric patients. Methods: Electronic databases were searched for studies comparing the QLB to conventional analgesic techniques in pediatric patients. The primary outcome was the need for rescue analgesia 12 and 24 hours after surgery. Secondary outcomes covered the Face-Legs-Activity-Cry-Consolability Scale (FLACC) scores at various time points; parental satisfaction; time to the first rescue analgesia; hospitalization time; block execution time; block failure rates, and adverse events. Results: Sixteen randomized controlled trials were analyzed involving 1,061 patients. The QLB significantly reduced the need for rescue analgesia both at 12 and 24 hours after surgery (12 hours, relative risk [RR]: 0.45; 95% confidence interval [CI]: 0.01, 0.88; 24 hours, RR: 0.51; 95% CI: 0.31, 0.70). In case of 24 hours after surgery, type 1 QLB significantly reduced the need for rescue analgesia (RR: 0.56; 95% CI: 0.36, 0.76). The QLB also exhibited lower FLACC scores at 1 hour (standardized mean difference [SMD]: -0.87; 95% CI: -1.56, -0.18) and 6 hours (SMD: -1.27; 95% CI: -2.33, -0.21) following surgery when compared to non-QLB. Among QLBs, type 2 QLB significantly extended the time until the first rescue analgesia (SMD: 1.25; 95% CI: 0.84, 1.67). No significant differences were observed in terms of parental satisfaction, hospitalization time, block execution time, block failure, or adverse events between QLB and non-QLB groups. Conclusions: The QLB provides non-inferior analgesic efficacy and safety to conventional methods in pediatric patients.

• Journal of Internet Computing and Services
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• v.21 no.3
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• pp.93-102
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• 2020

In order for data obtained through all stages of digital crime investigation to be recognized as evidence capability, it must satisfy legal / technical requirements. In this paper, we propose a mechanism and implement software to provide digital forensic evidence by automatically recovering files by scanning / inspecting the unallocated area inside the storage disk block without relying on information provided by the file system. The proposed technique checks / analyzes the RAW disk data of the system under analysis in 512-byte block units based on information on the storage format / file structure of various files stored on the disk without referring to the file system-related information provided by the operating system. The file carving process was implemented, and a smart carving mechanism was proposed to intelligently restore deleted or damaged files in the storage device. As a result, we have provided a block based smart carving method to intelligently identify fragmented and damaged files in storage efficiently for forgery analysis on digital forensic investigation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.1
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• pp.33-41
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• 2012

A differential fault analysis(DFA) is one of the most important side channel attacks on block ciphers. Most block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. PRESENT is a 64-bit block cipher with 80/128-bit secret keys and has a 31-round SP-network. So far, several DFAs on PRESENT have been proposed. These attacks recovered 80, 128-bit secret keys of PRESENT with 8~64 fault injections. respectively. In this paper, we propose an improved DFA on PRESENT-80/128. Our attack can reduce the complexity of exhaustive search of PRESENT-80(resp. 128) to on average 1.7(resp. $2^{22.3}$) with 2(resp. 3) fault injections, From these results, our attack results are superior to known DFAs on PRESENT.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.725-732
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• 2003

It was achieved that Rowecell test for this undisturbed sample was picked by Block sampler($\phi$:250mm, L:500mm) and hydraulic piston sampler($\phi$:76mm, L:850mm) in the marine clay of YONGYUDO and YEONGJONGDO in this research. Ratio of coefficient of consolidation was analyzed through comparison with C$\_$h/ by CPTu and C$\_$v/ and C$\_$h/ by existent consolidation test. According to analysis, coefficient of consolidation of block sample is fairly greater than coefficient of consolidation of piston sample. And the bigger diameter of undisturbed sample, sample disturbance could know decreasing. Coefficient of consolidation by Rowecell test measured more greatly than coefficient of consolidation by existent consolidation test. Rowecell test could know decreasing consolidation rate because of smear effect by Mandrel injection. Also, C$\_$h/ by CPTu shows deviation by each analysis method, selection of suitable analysis method judged by important leading in the coefficient of consolidation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2411-2429
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• 2013

In this paper, we extend the case of information exchange error mitigation for the distributed orthogonal space-time block code (DOSTBC) for two transmit antennas to distributed quasi-orthogonal space-time block code (DQOSTBC) for four transmit antennas. A rate 1 full-diversity DQOSTBC for four transmit antennas is designed. The code matrix changes according to different information exchange error cases, so full diversity is maintained even if not all information exchange is correct. We also perform analysis of the pairwise error probability. The performance analysis indicates that the proposed rate 1 DQOSTBC outperforms rate 1/2 DOSTBC for four transmit antennas at the same transmission rate, which is confirmed by the simulation results.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.510-517
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• 2012

Piccolo-80 is a 64-bit ultra-light block cipher suitable for the constrained environments such as wireless sensor network environments. In this paper, we propose a differential fault analysis on Piccolo-80. Based on a random byte fault model, our attack can the secret key of Piccolo-80 by using the exhaustive search of $2^{24}$ and six random byte fault injections on average. It can be simulated on a general PC within a few seconds. This result is the first known side-channel attack result on Piccolo-80.

• Journal of Welding and Joining
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• v.21 no.5
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• pp.518-524
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• 2003

The block assembly of ship consists of a series of heat processes such as cutting, bending, welding, residual stress relaxation and fairing. With the fast development of computers, the thermal elasto-plastic analysis method has become a versatile tool for practical applications in the ship production. If numerical analysis is proved to be an advantageous tool to predict the residual deformation due to various heat processes, the optimum methods which can remove the welding distortion can be presented at each assembly stage, which will result in great progress in improving the accuracy of block assembly. In order to minimize the weld-induced angular distortion in thick weldments, this paper proposes the optimum groove design for various plate thickness as the distortion control method. The validity of this method has been substantiated by a number of numerical simulations and experiments.