• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.5
• /
• pp.572-582
• /
• 2018

In this paper, we have calculated a formular for sabot-trajectory of shipboard projectile including ship motion and generated trajectory-range function for analysing interference with structure of naval ship. We make formula to approximate the ship motion data of naval ship using optimization technique. Through this formula, we calculate the velocities and accelerations of sabot caused by ship motion(surge, sway, heave, roll, pitch, yaw) and then, we produce the formula about the trajectory of sabot including effects of ship motion in addition to previous study which had considered the effects of the pressure of flume, friction force, etc. To investigate interference with ship structures, we make the trajectory-range functions and then extract the nearest or farthest trajectory to ship structure. Through these data, we can conform whether the interference is happened or not.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.77.1-77.1
• /
• 2015

The Center for Advanced Meta-Materials (CAMM) was launched in 2014 as a center for Global Frontier Projects supported by the Ministry of Science, ICT and Future Planning. The center is geared towards developing core technologies in controlling wave energies by incorporating creative artificial structures of sub-wavelength sizes. Furthermore, the center not only investigates novel meta-materials and devices but also builds new design, fabrication and application platforms in order to realize these technologies. The center will create new markets in various industries such as national defense, housing and medical care. In order to accomplish its goals, CAMM is composed of three major divisions: the fabrication/characterization technologies and application division, the advanced metamaterials for electromagnetic wave division and the advanced metamaterials for mechanical wave division. The center will concentrate its efforts in bringing innovations to conventional technologies in sectors such as machinery, ICT, energy and biomedical technology by adopting the use of advanced metamaterial systems. In this talk, we will introduce principles of advanced wave control and describe some advanced metamaterials which can provide new solutions for various social problems in future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.8
• /
• pp.791-796
• /
• 2009

A hybrid iterative physical optics-method of moments(IPO-MoM) technique is presented for the analysis of jet engine structures which are both electrically large and complex. In this technique, the IPO method is used to analyze smooth inlet region and the MoM method is used to analyze electrically complex region inclusive of blades and hub. It is efficient and accurate by virtue of combining the respective merits of both methods. Numerical results are presented and validated through comparison with Mode-FDTD and measured results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1366-1370
• /
• 2007

Predicting the noise radiated from vibrating structures is important in the automotive, aerospace, construction equipment, and defense industries. In this paper, a numerical implementation of the boundary element method in solving the Helmholtz integral equation for radiated noise prediction is presented. To predict the noise emitted by vibrating structure, the developed code can use the results from a structure analysis performed by a multi-purpose structural finite element code like ANSYS and directly measured data by non-contact vibration sensor like Laser Doppler Vibrometer. To verify the accuracy of developed code, two kinds of verification are perfomed. Firstly, the computer code used the harmonic analysis results of ANSYS in simple model and try to match with SYSNOISE. After matching with simulation results, the code compared with the result from SYSNOISE which used the velocity data from the LDV measurement with different number of points. The performance of the developed code for vibro-acoustic noise prediction is presented using the experimental results of the non-contact sensor

• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.4
• /
• pp.467-475
• /
• 2016

Ultrasonic propagation imaging (UPI) has shown great potential for detection of impairments in complex structures and can be used in wide range of non-destructive evaluation and structural health monitoring applications. The software implementation of such algorithms showed a tendency in time-consumption with increment in scan area because the processor shares its resources with a number of programs running at the same time. This issue was addressed by using field programmable gate arrays (FPGA) that is a dedicated processing solution and used for high speed signal processing algorithms. For this purpose, we need an independent and flexible block of logic which can be used with continuously evolvable hardware based on FPGA. In this paper, we developed an FPGA-based ultrasonic propagation imaging system, where FPGA functions for both data acquisition system and real-time ultrasonic signal processing. The developed UPI system using FPGA board provides better cost-effectiveness and resolution than digitizers, and much faster signal processing time than CPU which was tested using basic ultrasonic propagation algorithms such as ultrasonic wave propagation imaging and multi-directional adjacent wave subtraction. Finally, a comparison of results for processing time between a CPU-based UPI system and the novel FPGA-based system were presented to justify the objective of this research.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.4
• /
• pp.359-364
• /
• 2013

Inordinate stress causes disorders of various systems in humans and activates defense mechanisms to maintain homeostasis in the body. Sleep is a vital, highly organized process regulated by complex systems of neuronal networks and neurotransmitters. Sleep is an essential biological process whose underlying regulating involves numerous anatomical structures and biochemical substances that can be compromised by stress and by the immune system. Gamma-amino butyric acid (GABA) is the main inhibitory neurotransmitter of the central nervous system, and activation of GABAA receptors is known to favor sleep. This study was conducted to evaluate the possible application of Lactobacillus brevis BJ20 fermentation to improve the functional qualities of sea tangle Saccharina japonica and oyster Crassostrea gigas. Antioxidant activity was determined by assaying levels of radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide. L. brevis BJ20 fermentation of sea tangle and oyster enhanced both antioxidant and antiinflammatory activities. These results suggested that L. brevis BJ20 fermented sea tangle and oyster could be used for alleviation of stress and to promote sleep.

• Korean Journal of Environment and Ecology
• /
• v.24 no.3
• /
• pp.258-263
• /
• 2010

To study on the typical domatia structure, the leaves of six broad-leaved tree species were examined. Domatia of the leaves of the broad-leaved trees is the defense strategies against hervivory of many broad-leaved tree species. We observed four type domatia; Pouch type, Tuft type, Pocket type, and Pocket + tuft type. This result suggests that broad-leaved trees have develope leaf domatia structures for mutualism with predatory mites.

• 전자공학회논문지 IE
• /
• v.45 no.2
• /
• pp.13-19
• /
• 2008

The main advantage of the TLM analysis method is the ease with which even the most complicated transmission line structures. In this paper, using symmetrical condensed node(SCN), the TLM numerical technique has been successfully a lied to microstrip meander line. A detailed technique of the symmetrical condensed node(SCN) may be used to model planar microstrip transmission line is presented. Also, the S-parameters $S_{11}$ and $S_{21}$ of two types of microstrip meander line have been computed. From obtained results, TLM analysis is shown to be an efficient method for modeling complicated structure of planar microstrip transmission line. The TLM results presented here are useful in the design of microwave integrated circuits at higher frequencies region.

• BMB Reports
• /
• v.38 no.5
• /
• pp.507-516
• /
• 2005

Antimicrobial peptides (AMPs) have been isolated and characterized from tissues and organisms representing virtually every kingdom and phylum. Their amino acid composition, amphipathicity, cationic charge, and size allow them to attach to and insert into membrane bilayers to form pores by 'barrel-stave', 'carpet' or 'toroidal-pore' mechanisms. Although these models are helpful for defining mechanisms of AMP activity, their relevance to resolving how peptides damage and kill microorganisms still needs to be clarified. Moreover, many AMPs employ sophisticated and dynamic mechanisms of action to carry out their likely roles in antimicrobial host defense. Recently, it has been speculated that transmembrane pore formation is not the only mechanism of microbial killing by AMPs. In fact, several observations suggest that translocated AMPs can alter cytoplasmic membrane septum formation, reduce cell-wall, nucleic acid, and protein synthesis, and inhibit enzymatic activity. In this review, we present the structures of several AMPs as well as models of how AMPs induce pore formation. AMPs have received special attention as a possible alternative way to combat antibiotic-resistant bacterial strains. It may be possible to design synthetic AMPs with enhanced activity for microbial cells, especially those with antibiotic resistance, as well as synergistic effects with conventional antibiotic agents that lack cytotoxic or hemolytic activity.

• Biomedical Science Letters
• /
• v.15 no.3
• /
• pp.257-260
• /
• 2009

Toll-like receptors (TLRs) recognize molecular structures derived from microbes including bacteria, viruses, yeast, and fungi. TLRs have emerged as a major signaling component of the mammalian host defense. TLR4 is a member of the Toll family that senses lipopolysaccharide (LPS), a cell wall component of gram negative bacteria. LPS recognition by TLR4 requires an additional accessory molecule, MD-2. LPS induces the activation of NF-${\kappa}B$ and IRF3 through MyD88 or TRIF-dependent pathways. The activation of NF-${\kappa}B$ leads to the induction of inflammatory gene products including cytokines and cyclooxygenase-2 (COX-2). This study was carried out to investigate the anti-inflammatory effects of oak wood vinegar. Oak wood vinegar inhibits the NF-${\kappa}B$ activation and COX-2 expression induced by LPS. These results provide new ideas to understand the mechanism of oak wood vinegar for its anti-bacterial and anti-inflammatory activities.