• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.270-272
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• 2005

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents from negative return rails become a pending problem to the safety of nearby underground infrastructures, such as gas pipelines, water distribution lines, heat pipelines, POF cables, etc. The mitigation of such interference, however, is mainly dependent on stray current drainage bond methods, which connect the underground metallic structures to the negative feeder cables attached to the rails with diodes (polarized drainage) or thyristors (forced drainage). Despite some merits of these methods, they increase the total amount of stray currents from rails and cause other interference problems. In this paper, we summarize the domestic conditions of stray current interference and describe a conceptual design of other mitigation methods for such interference.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3838-3846
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• 1996

A method is proposed to obtain the stress intensity factors of multiple cracks lying on many straight llnes in an infinite isotropic plate. In this mehtod, analytical solutions for collinear multiple cracks subject to surface point forces are obrained and used as Green functions. For the multiple cracks lying onmany straight lines, the equivalent crack surface tractions are obtained by using the alternating method and the stress intensity factors are calculated. By using the proposed method several useful problems are solved and discussed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.102-116
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• 2020

The existence of appropriate teaching materials in foreign language is very essential especially if it is related to safety. Among them, the importance of textbooks is more emphasized because there is no suitable education or curriculum for EPTA (English proficiency test of aviation). A good textbook not only presents the right direction to study but also provides an efficient way to learn. This research exploded how well textbooks for EPTA are organized and analyzed current pilots' responses whether the textbooks are suitable for preparing EPTA through the questionnaire. The conclusion drawn is that textbooks for EPTA should be designed to encourage current and pre-pilots to learn how to communicate with controllers efficiently and briefly, and also should provide proper guide lines for preparing EPTA.

• Toxicological Research
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• v.14 no.2
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• pp.123-127
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• 1998

BRCA1 is a tumor suppresser gene in familial cases of breast cancer. It has been controversial whether the subcellular localization of BRCA1 is located in nuclei or cytoplasm in normal human breast cells. We found that a p220 protein was expressed in Type II Normal human breast epithelial cells (NHBEC) but not in Type I NHBEC in Western blot analysis using the 17F8 (3A2) antibody. Immunostaining using the same antibody revealed positive staining in nuclei, cytoplasm and perinuclei of Type II cells and negative staining in Type I NHBEC. The p220 protein, however, was expressed in SV40 immortalized Type I NHBEC and tumorigenic cells derived from them after x-ray and neu oncogene treatment. The subcelluar localization was mostly cytoplasmic and punctate in the nuclei. The breast carcinoma cell lines, MCF-7 and T47D, also expressed the p220 protein. Using RT-PCR, we observed the expression of BRCA1 mRNA in both Type I and Type II NHBEC. This result indicated that there might be mechanisms involved in post-translational or translational regulation of BRCA1 gene. It is speculated that the absence of BRCA1 protein expression in Type I NHBEC might playa role in their susceptibility to neoplastic transformation.

• Steel and Composite Structures
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• v.36 no.4
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• pp.383-398
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• 2020

This paper investigates the progressive collapse behavior of 3D steel-framed gravity buildings under fires with a cooling phase. The effect of fire protections and bracing systems on whether, how, and when a gravity building collapses is studied. It is found that whether a building collapses or not depends on the duration of the heating phase, and it may withstand a "short-hot" fire, but collapses under a mild fire or a "long-cool" fire. The collapse time can be conservatively determined by the time when the temperature of steel columns reaches a critical temperature of 550 ℃. It is also found that the application of a higher level of fire protection may prevent the collapse of a building, but may also lead to its collapse in the cooling phase due to the delayed temperature increment in the heated members. The tensile membrane action in a heated slab can be resisted by a tensile ring around its perimeter or by tensile yielding lines extended to the edge of the frame. It is recommended for practical design that hat bracing systems should be arranged on the whole top floor, and a combination of perimeter and internal vertical bracing systems be used to mitigate the fire-induced collapse of gravity buildings. It is also suggested that beam-to-column connections should be designed to resist high tensile forces (up to yielding force) during the cooling phase of a fire.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.438-445
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• 2009

We investigated global gene expression from both mouse liver and mouse hepatic cell lines treated with acetaminophen (APAP) in order to compare in vivo and in vitro profiles and to assess the feasibility of the two systems. During our analyses of gene expression profiles, we picked up several down-regulated genes, such as the cytochrome P450 family 51 (Cyp51), sulfotransferase family cytosolic 1C member 2 (Sult1c2), 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 (Hmgcs1), and several genes that were up-regulated by APAP, such as growth arrest and DNA-damage-inducible 45 alpha (Gadd45a), transformation related protein 53 inducible nuclear protein 1 (Trp53inp1) and zinc finger protein 688 (Zfp688). For validation of gene function, synthesized short interfering RNAs (siRNAs) for these genes were transfected in a mouse hepatic cell line, BNL CL.2, for investigation of cell viability and mRNA expression level. We found that siRNA transfection of these genes induced down-regulation of respective mRNA expression and decreased cell viability. siRNA transfection for Cyp51 and others induced morphological alterations, such as membrane thickening and nuclear condensation. Taken together, siRNA transfection of these six genes decreased cell viability and induced alteration in cellular morphology, along with effective inhibition of respective mRNA, suggesting that these genes could be associated with APAP-induced toxicity. Furthermore, these genes may be used in the investigation of hepatotoxicity, for better understanding of its mechanism.

• The Korean Journal of Applied Statistics
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• v.27 no.4
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• pp.543-552
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• 2014

High bandwidth RF such as Bluetooth, GPRS, EDGE, 3GSM, HSDPA is papular in the mobile phone market. A non-conducting metal coating process requires an e-beam deposition of metal, two steps of UV hard coating primer and top coating; however, it is inefficient. We navigate to the electron beam irradiation conditions(resin surface treatment conditions) in the PC/ABS resin injection process. By analyzing the experimental results, we find the optimum development conditions for the electro deposition pre-treatment process and mass production lines using the plasma generated electron beam source.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.77-82
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• 2010

This study evaluated the characteristics and reliability of an auger crane with a built-in hydraulic extender. The field test of the hydraulic extender was performed with the hydraulic lines filled with hydraulic fluid and free of air. The pressure generated during the test was measured with a digital pressure gauge. The crane was considered to have undergone one cycle of the excavation process after it had performed excavation under three conditions at the same location. This process was performed three times in total. From the results of the excavation using the hydraulic extender, it was found that the maximum pressure and torque measured were 19.9 [MPa] and 895.4 [$kgf{\cdot}m$], respectively. The rotation force of the auger crane generated at this time signifies a horizontal force. If the excavation diameter of the auger crane is increased, the rotation speed is reduced causing the circumferential speed to also be reduced. The torsional shear stress of the extendable auger crane was calculated to be approximately 23.5 [MPa]. However, the rotation shaft material used for this system was carbon steel for machine structural use (SM45C). Since the minimum torsional yield stress is greater than 150 [MPa] according to KS D 3752, it means the equipment has secured a safety factor greater than 6. Therefore, it was found that when performing work using the extendable auger crane, it exhibited no problems with the safety and reliability of its shaft.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.127-135
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• 2017

Recently, the most brand new vehicles contain a lot of ECU for comfortable and safety driving environments. For efficient communication network among ECUs, almost car manufactures use CAN protocol which enables to decrease the number of communication lines dramatically and ensures higher data transmission reliability. However, CAN dose not ensure authentication of CAN data frame. So it is vulnerable to replay-attack on CAN data frame. This paper proposes the practical message authentication technique for In-vehicle CAN. To transmit data and MAC together, it is very useful to use the short length of MAC after considering limited space of CAN data frame. However to ensure safety of MAC, additional technique is required. We suggested a message authentication technique that can be usefully applied to build a safety network inside the vehicle because it considers limited data payload of CAN.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.131-139
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• 1992

Based on the equi-flooding line theory, this study suggests method of evaluating safety of detent tion reservoirs with drainage pumping facilities in Seoul metropolitan area, and derives equi-flooding lines according to destruction frequency for each detention reservoir. In most part of detention reservoirs, its flood prevention are so much dependent upon drainage capacity that inland flooding prevention can be serious problems in case of its malfunction. In this study, the detention reservoirs which are below 5 year destruction frequency estimated as 29.3%, and below 10 year as 39.6% of the total. To improve reservoir safety, the detention reservoir capacities (including drainage and pumping capacity) should be upgraded above 20 year in its destruction frequency, and its reinforcement capacities are calculated.