• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.65-72
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• 2004

A melamine-urea-formaldehyde (MUF) resin, based on 5 percent melamine addition of the resin solids weight, was synthesized in the laboratory for particleboard (PB) manufacture. Laboratory PBs were made with the MUF resin at three press times (3, 4, 5 min) and two resin application rates (6, 8 percent). Enclosed caul system was used for collecting the exhaust gases materials generated during the hot-pressing of PBs. Exhaust gases materials generated inside the enclosed caul during the hot-pressing of PBs were collected in a controlled air stream. Formaldehyde from the exhaust gases collected was determined per a chromotropic method of the National Institute of Occupational Safety and Health Method 3500. The measurement results showed that formaldehyde emissions during the hot-pressing of PB significantly increased with increasing press time, and MUF resin application rates. PB' performance test results showed that internal bond (IB) of PB made with 3-minute press time exceeded the minimum requirement for KS F 3104 PB type 8.0.

• Structural Monitoring and Maintenance
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• v.9 no.1
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• pp.43-57
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• 2022

One of the instances which demand structural engineer's greatest attention and upgradation is the changing live load requirement in bridge design code. The challenge increases in developing countries as the pace of infrastructural growth is being catered by the respective country codes with bigger and heavier vehicles to be considered in the design. This paper presents the case study of India where Indian Roads Congress (IRC) codes in its revised version from 2014 to 2017 introduced massive Special vehicle (SV) around 40 m long and weighing 3850 kN to be considered in the design of road bridges. The code does not specify the minimum distance between successive special vehicles unlike other loading classes and hence the consequences of it form the motivation for this study. The effect of SV in comparison with Class 70R, Class AA, Class A, and Class B loading is studied based on the maximum bending moment with moving load applied in Autodesk Robot Structural Analysis. The spans considered in the analysis varied from 10 m to 1991 m corresponding to the span of Akashi Kaikyo Bridge (longest bridge span in the world). A total of 182 analyses for 7 types of vehicles (class B, class A, class 70R tracked, class 70R wheeled, class AA tracked, AA wheeled, and Special vehicle) on 26 different span lengths is carried out. The span corresponding to other vehicles which would equal the bending moment of a single SV is presented along with a comparison relative to Standard Uniformly Distributed Load. Further, the results are presented by introducing a new parameter named Intensity Factor which is proven to relate the effect of axle spacing of vehicle on the normalized bending moment developed.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.499-507
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• 2023

The core of the liquefied natural gas (LNG) carrier cargo containment system (CCS) is to store and transport LNG safely under temperatures below -163 degrees Celsius. The secondary barrier of the LNG CCS is adopted to prevent LNG leakage from CCS to the ship's hull structure. Recently, as the size of the LNG CCS increases, various studies have been conducted on the applied temperature and load ranges. The present study investigates the working condition-dependent bonding strength of the PU15 adhesives of the secondary barrier. In addition, the mechanical performance is analyzed at a cryogenic temperature of -170 degrees Celsius, and the failure surface and failure mode are investigated depending on the working condition of the bonded process. Even though the RSB and FSB-based fracture mode was confirmed, the results showed that all the tested scenarios satisfied the minimum requirement of the regulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.7
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• pp.1823-1840
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• 2023

In order to improve spectral efficiency and reduce power consumption for reconfigurable intelligent surface (RIS) assisted wireless communication systems, a joint design considering irregular RIS topology, RIS on-off switch, power allocation and phase adjustment is investigated in this paper. Firstly, a multi-dimensional variable joint optimization problem is established under multiple constraints, such as the minimum data requirement and power constraints, with the goal of maximizing the system energy efficiency. However, the proposed optimization problem is hard to be resolved due to its property of nonlinear nonconvex integer programming. Then, to tackle this issue, the problem is decomposed into four sub-problems: topology design, phase shift adjustment, power allocation and switch selection. In terms of topology design, Tabu search algorithm is introduced to select the components that play the main role. For RIS switch selection, greedy algorithm is used to turn off the RISs that play the secondary role. Finally, an iterative optimization algorithm with high data-rate and low power consumption is proposed. The simulation results show that the performance of the irregular RIS aided system with topology design and RIS selection is better than that of the fixed topology and the fix number of RISs. In addition, the proposed joint optimization algorithm can effectively improve the data rate and energy efficiency by changing the propagation environment.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.18-25
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• 2024

Background: The Discovery Elbow System (DES) utilizes a polyethylene bearing within the ulnar component. An exchange bearing requires preoperative freezing and implantation within 2 minutes of freezer removal to allow insertion. We report our outcomes and experience using this technique. Methods: This was an analysis of a two-surgeon consecutive series of DES bearing exchange. Inclusion criteria included patients in which exchange was attempted with a minimum 1-year follow-up. Clinical and radiographic review was performed 1, 2, 3, 5, 8 and 10 years postoperative. Outcome measures included range of movement, Oxford Elbow Score (OES), Mayo Elbow Performance Score (MEPS), complications and requirement for revision surgery. Results: Eleven DESs in 10 patients were included. Indications were bearing wear encountered during humeral component revision (n=5); bearing failure (n=4); and infection treated with debridement, antibiotics and implant retention (DAIR; n=2). Bearing exchange was conducted on the first attempt in 10 cases. One case required a second attempt. One patient developed infection postoperatively managed with two-stage revision. Mean follow-up of the bearing exchange DES was 3 years. No further surgery was required, with no infection recurrence in DAIR cases. Mean elbow flexion-extension and pronosupination arcs were 107°(±22°) and 140° (±26°). Mean OES was 36/48 (±12) and MEPS was 83/100 (±19). Conclusions: Our results support the use of DES bearing exchange in cases of bearing wear with well-fixed stems or acute infection. This series provides surgeons managing DES arthroplasty with management principles, successful and reproducible surgical techniques and expected clinical outcomes in performing DES polyethylene bearing exchange. Level of evidence: IV.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.1-9
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• 2024

Multivariate Quadratic (MQ)-based digital signature schemes have advantages such as ease of implementation and small signature sizes, making them promising candidates for post-quantum cryptography. To enhance the efficiency of such MQ-based digital signature schemes, utilizing sparse matrices have been proposed, including HiMQ, which has been standardized by Korean Telecommunications Technology Association standard. However, HiMQ shares a similar key structure with Rainbow, which is a representative MQ-based digital signature scheme and was broken by the MinRank attack proposed in 2022. While HiMQ was standardized by a TTA and recommended parameters were provided, these parameters were based on cryptanalysis as of 2020, without considering recent attacks. In this paper, we examine attacks applicable to MQ-based digital signatures, specifically targeting HiMQ, and perform a security analysis. The most effective attack against HiMQ is the combined attack, an improved version of the MinRank attack proposed in 2022, and none of the three recommended parameters satisfy the desired security strength. Furthermore, HiMQ-128 and HiMQ-160 do not meet the minimum security strength requirement of 128-bit security level.

• International Journal of Computer Science & Network Security
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• v.24 no.8
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• pp.85-104
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• 2024

The DNA (Deoxyribonucleic Acid) database size increases tremendously transmuting from millions to billions in a year. Ergo for storing, probing the DNA database requires efficient lossless compression and encryption algorithm for secure communication. The DNA short pattern repetitions are of paramount characteristics in biological sequences. This algorithm is predicated on probing exact reiterate, substring substitute by corresponding ASCII code and engender a Library file, as a result get cumulating of the data stream. In this technique the data is secured utilizing ASCII value and engendering Library file which acts as a signature. The security of information is the most challenging question with veneration to the communication perspective. The selective encryption method is used for security purpose, this technique is applied on compressed data or in the library file or in both files. The fractional part of a message is encrypted in the selective encryption method keeping the remaining part unchanged, this is very paramount with reference to selective encryption system. The Huffman's algorithm is applied in the output of the first phase reiterate technique, including transmuting the Huffman's tree level position and node position for encryption. The mass demand is the minimum storage requirement and computation cost. Time and space complexity of Repeat algorithm are O(N²) and O(N). Time and space complexity of Huffman algorithm are O(n log n) and O(n log n). The artificial data of equipollent length is additionally tested by this algorithm. This modified Huffman technique reduces the compression rate & ratio. The experimental result shows that only 58% to 100% encryption on actual file is done when above 99% modification is in actual file can be observed and compression rate is 1.97bits/base.

• Journal of Life Science
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• v.20 no.5
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• pp.717-722
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• 2010

The safety of animal feed was evaluated by analyzing the levels of heavy metals (Pb, Cr, Cd, As, Se and Ag) in cattle, swine, and poultry feeds and the levels of Cu, Zn and P in swine feed. Feeds used in the analysis were produced in Korea from 2004 through the first half of 2007. The results of the study revealed that, with the exception of Cd, the concentration of heavy metals were much lower than the Minimum Regulation Levels (MRLs). However, the Cd concentration exceeded the MRL in 1 of 987 swine feed samples in 2005, as well as in 4 of 1,239 swine feed samples and 1 of 778 poultry feed samples in 2006. The levels of Cu, Zn and P in swine feed were compared with the swine breeding standard. The results of this analysis revealed that the Cu concentrations in the samples exceeded the MRL for growing pigs by 0.97%, and that for finishing and breeding pigs by 9.9%. In addition, the Cu levels (80.98 ppm for piglet, 44.82 ppm for growing pigs, 19 ppm for finishing and breeding pigs) in swine feed showed higher levels compared to 3.5-6.0 ppm, which is the Cu requirement for swine. Furthermore, the results of the Zn analysis revealed that the samples exceeded the MRL for piglets, growing pigs, and finishing and breeding pigs by 5.7%, 7.7%, and 9.3%, respectively. Finally, the average concentration of P in swine feed was 0.74%, which is almost the same as the phosphate requirement for swine.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.30-38
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• 2008

Petroleum-based resin adhesives have extensively been used for the production of wood panels. However, with the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the adhesive resins, it is necessary to be developed new adhesive systems. In this study, the potential of okara, which is a residue wasted from the production of tofu, for the development of bio-based adhesives was investigated. At first, the physical and chemical properties of okara were examined. After okara was hydrolyzed in acidic and/or alkaline solutions, okara-based adhesive resins were formulated with the mixtures of the okara hydrolyzates and phenol formaldehyde (PF) prepolymer. The adhesive resins were used for the fabrication of plywood panels, and then the adhesive strength and formaldehyde emission of the plywood panels were measured to examine the applicability of the resin adhesives for the production of plywood panels. The solids content and pH of the okara used in this study were around 20% and weak acidic state, respectively. In the analysis of its chemical composition, the content of carbohydrate was the highest, and followed by protein. The shear strengths of plywood fabricated with okara-based resin adhesives exceeded a minimum requirement of KS standard for ordinary plywood, but its wood failure did not reach the minimum requirement. In addition, the formaldehyde emissions of all plywood panels were higher than that of E1 specified in the KS standard. Based on these results, okara has the potential to be used as a raw material of environmentally friendly adhesive resin systems for the production of wood panels, but further researches - biological hydrolysis of okara and various formulations of PF prepolymer - are required to improve the adhesive strength and formaldehyde emission of okara-based resin adhesives.

• The Korean Journal of Air & Space Law and Policy
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• v.7
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• pp.101-134
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• 1995

Article 3 Paragraph 1 of the Warsaw Convention regulates the requirements of passenger tickets, Article 4 Paragraph 3, the requirements of baggage tickets, Article 8, the requirements of airway bills. In this article the writer has discussed the legal nature of the documents of air carriage, such as air waybills, passenger tickets and baggage checks. Further, the writer has also discussed several issues relating to the use of the documents of air carriage under the Warsaw Convention. Article 3 Paragraph 2, as well as Article 4 Paragraph 4 and 9 provides that the carrier shall not be entitled to avail himself of the provisions of the Convention which evade or limit his liability. In particular, the Montreal Agreement of 1966 provides that the notification on the carrier's liability in passenger ticket should be printed in more than 10 point type size with contrasting ink colors. However, another question is whether the carrier shall not be entitled to avail himself of the liability limit under the Convention in case the type size is below 10 points. The Convention does not specify the type size of certain parts in passenger tickets and only provides that the carrier shall not be entitled to avail himself of liability limit, when a carrier fails to deliver the ticket to passenger. However, since the delivery of passenger tickets is to provide an opportunity for passengers to recognize the liability limit under the Convention and to map out a subsequent measures, the carrier who fails to give this opportunity shall not be entitled to avail himself of the liability limit under the Convention. But some decisions argue that when the notice on the carrier's liability limit is presented in a fine print in a hardly noticeable place, the carrier shall not be entitled to avail himself under the Convention. Meanwhile, most decisions declare that regardless of the type size, the carrier is entitled to avail himself of liability limit of the provisions of the Convention. The reason is that neither the Warsaw Convention nor the Montreal Agreement stipulate that the carrier is deprived from the right to avail himself of liability limit of the provisions of the Convention when violating the notice requirement. In particular, the main objective of the Montreal Agreement is not on the notice of liability limit but on the increase of it. The latest decisons also maintain the same view. This issue seems to have beeen settled on the occasion of Elisa Chan, et al. vs. Korean Airlines Ltd. The U.S. Supreme Court held that the type size of passenger ticket can not be a target of controversy since it is not required by law, after a cautious interpretation of the Warsaw Convention and the Montreal Agreement highlighting the fact that no grounds for that are found both in the Warsaw Convention and the Montreal Agreement. Now the issue of type size can hardly become any grounds for the carrier not to exclude himself from the liability limit. In this regard, any challenge to raise issue on type size seems to be defeated. The same issue can be raised in both airway bills and baggage tickets. But this argument can be raised only to the tranportation where the original Convention is applied. This creates no problem under the Convention revised by the Hague Protocol, because the Hague Protocol does not require any information on weight, bulk, size, and number of cargo or baggage. The problem here is whether the carrier is entitled to avail himself of the liability limit of the provisions of the Convention when no information on number or weight of the consigned packages is available in accordance with Article 4 of the Convention. Currently the majority of decisions show positive stance on this. The carrier is entitled to avail himself of the liability limit of the provisions of the Convention when the requirement of information on number and weight of consigned packages is skipped, because these requirements are too technical and insubstancial. However some decisions declare just the opposite. They hold that the provisions of the Convention Article 4 is clear, and their meaning and effect should be imposed on it literally and that it is neither unjust nor too technical for a carrier to meet the minimum requirement prescribed in the Convention. Up to now, no decisions by the U.S. Supreme Court on this issue is available.