• The Journal of Korean Institute of Next Generation Computing
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• 제13권6호
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• pp.124-131
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• 2017

Recently, drone is extending its range of usability. For example, the delivery, agriculture, industry, and entertainment area take advantage of drone mobilities. To control real drones, it needs huge amount of drone control training steps. However, it is risky; falling down, missing, destroying. The virtual drone system can avoid such risks. We reason that what kinds of technologies are required for building the virtual drone system. First, it needs that the virtual drone authoring tool that can assemble drones with the physical restriction in the virtual environment. We suggest that the drone assembly method that can fulfill physical restrictions in the virtual environment. Next, we introduce the virtual drone simulator that can simulate the assembled drone moves physically right in the virtual environment. The simulator produces a high quality rendering results more than 60 frames per second. In addition, we develop the physics engine based on SILS(Software in the loop simulation) framework to perform more realistic drone movement. Last, we suggest the virtual drone controller that can interact with real drone controllers which are commonly used to control real drones. Our virtual drone system earns 7.64/10.0 user satisfaction points on human test: the test is done by one hundred persons.

• Progress in Superconductivity
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• 제8권1호
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• pp.33-39
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• 2006

We have developed a second-order double relaxation oscillation SQUID(DROS) gradiometer with a baseline of 35 mm, and constructed a poorly magnetically-shielded room(MSR) with an aluminum layer and permalloy layers for magnetocardiography(MCG). The 2nd-order DROS gradiometer has a noise level of 20 $fT/{\surd}Hz$ at 1 Hz and 8 $fT/{\surd}Hz$ at 200 Hz inside the heavily-shielded MSR with a shielding factor of $10^3$ at 1 Hz and $10^4-10^5$ at 100 Hz. The poorly-shielded MSR, built of a 12-mm-thick aluminum layer and 4-6 permalloy layers of 0.35 mm thickness, is 2.4mx2.4mx2.4m in size, and has a shielding factor of 40 at 1 Hz, $10^4$ at 100 Hz. Our 64-channel second-order gradiometer MCG system consists of 64 2nd-order DROS gradiometers, flux-locked loop electronics, and analog signal processors. With the 2nd-order DROS gradiometers and flux-locked loop electronics installed inside the poorly-shielded MSR, and with the analog signal processor installed outside it, the noise level was measured to be 20 $fT/{\surd}Hz$ at 1 Hz and 8 $fT/{\surd}Hz$ at 200 Hz on the average even though the MSR door is open. This result leads to a low noise level, low enough to obtain a human MCG at the same level as that measured in the heavily-shielded MSR. However, filters or active shielding is needed fur clear MCG when there is large low-frequency noise from heavy air conditioning or large ac power consumption near the poorly-shielded MSR.

• Sleep Medicine and Psychophysiology
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• 제4권1호
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• pp.15-28
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• 1997

Longterm memory is encoded in the neuronal connectivities of the brain. The most successful models of human memory in their operations are models of distributed and self-organized associative memory, which are founded in the principle of simulaneous convergence in network formation. Memory is not perceived as the qualities inherent in physical objects or events, but as a set of relations previously established in a neural net by simultaneousy occuring experiences. When it is easy to find correlations with existing neural networks through analysis of network structures, memory is automatically encoded in cerebral cortex. However, in the emergence of informations which are complicated to classify and correlated with existing networks, and conflictual with other networks, those informations are sent to the subcortex including hippocampus. Memory is stored in the form of templates distributed across several different cortical regions. The hippocampus provides detailed maps for the conjoint binding and calling up of widely distributed informations. Knowledge about the distribution of correlated networks can transform the existing networks into new one. Then, hippocampus consolidats new formed network. Amygdala may enable the emotions to influence the information processing and memory as well as providing the visceral informations to them. Cortico-striatal-pallido-thalamo-cortical loop also play an important role in memory function with analysis of language and concept. In case of difficulty in processing in spite of parallel process of informations, frontal lobe organizes theses complicated informations of network analysis through temporal processing. With understanding of brain mechanism of memory and information processing, the brain mechanism of mental phenomena including psychopathology can be better explained in terms of neurobiology and meuropsychology.

• Molecules and Cells
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• 제26권1호
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• pp.41-47
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• 2008

Mitogen-activated protein kinase (MAPK) signaling is a crucial component of eukaryotic cells; it plays an important role in responses to extracelluar stimuli and in the regulation of various cellular activities. The signaling cascade is evolutionarily conserved in the eukaryotic kingdom from yeast to human. In response to a variety of extracellular signals, MAPK activity is known to be regulated via phosphorylation of a conserved $T{\times}Y$ motif at the activation loop in which both threonine and tyrosine residues are phosphorylated by the upstream kinase. However, the mechanism by which both residues are phosphorylated continues to remain elusive. In the budding yeast, Saccharomyces cerevisiae, Fus3 MAPK is involved in the mating signaling pathway. In order to elucidate the functional mechanism of MAPK activation, we quantitatively profiled phosphorylation of the $T{\times}Y$ motif in Fus3 using mass spectrometry (MS). We used synthetic heavy stable isotope-labeled phosphopeptides and nonphosphopeptides corresponding to the proteolytic $T{\times}Y$ motif of Fus3 and accompanying data-dependent tandem MS to quantitatively monitor dynamic changes in the phosphorylation events of MAPK. Phosphospecific immunoblotting and the MS data suggested that the tyrosine residue is dynamically phosphorylated upon stimulation and that this leads to dual phosphorylation. In contrast, the magnitude of threonine phosphorylation did not change significantly. However, the absence of a threonine residue leads to hyperphosphorylation of the tyrosine residue in the unstimulated condition, suggesting that the threonine residue contributes to the control of signaling noise.

• Korean System Dynamics Review
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• 제16권3호
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• pp.5-29
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• 2015

The importance of the concept of safety culture has increased in the security of high-risk facility after Chernobyl accident in 1986. This paper elaborated the concept of safety culture and its main factors by Causal Loop Diagram. Due to the decline of safety culture, the occurrence of incidents and accidents require more and more corrective actions to the members of high-risk facilities and thereby increasing their workloads. Employees who must complete the task within the given time have to have time pressures and don't comply with the rules and procedures. Also, a schedule pressure is a big stress for employees, causing mistakes in precision work. In order to improve these problems, CLD of the safety culture in this paper suggests hiring more workers, re-allocation of given workloads and strengthen the learning, communication capabilities and safety leadership. In addition, the two real accident cases were analyzed to test the feasibility of the System Dynamic simulation model through the process of structuring the fault trees on the stationary black out accident in Kori unit 1 in South Korea and Kleen Energy power station explosion in US. The simulation results show that the various safety factors cause the serious accident combined with mechanical failure and safety culture will reduce the possibility of the accidents in these high-risk organizations. This simulation model can contribute to analyzing the impact of the organizational and human factors of safety culture and can provide the alternatives in high-risk facilities.

• Journal of Pharmaceutical Investigation
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• 제35권4호
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• pp.233-241
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• 2005

Ursolic acid (UA), a bioactive triterpene acid, has been known to increase collagen content in human skin in addition to other actions such as anti-inflammatory, skin-tumor prevention and anti-invasion. However, it is poorly soluble in water. Therefore, we firstly prepared microemulsion system with benzyl alcohol, ethanol and Cremophor EL, RH 40 and Brij 35 as surfactant in order to increase solubility of UA and then prepared microemulsion was dispersed in o/w cream base for the topical delivery of UA in an effort to improve anti-wrinkle effect. The pseudo-ternary phase diagrams were developed and various microemulsion formulations were prepared using benzyl alcohol as an oil, Cremophor EL, RH 40 and Brij 35 as a surfactant. The droplet size of microemulsions was characterized by dynamic light scattering. The accumulation of VA in the skin from topical cream was evaluated in vitro using hairless mouse skins. The mean droplet size was $26.8{\pm}6.6$ nm for microemulsions II with Cremophor EL. All UA creams showed pseudoplastic flow and hysterisis loop in their rheogram, depending on the type of materials added in topical creams. The in vitro accumulation data demonstrated the UA topical cream prepared with the combination of Poloxamer 407 and Xanthan gum as a copolymer showed higher accumulation percentage than those prepared with either Poloxamer 407 or Xanthan gum. These results suggest that UA topical cream using microemulsion systems may be promising for the topical delivery of UA.

• Korean Journal of Radiology
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• 제1권1호
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• pp.19-24
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• 2000

Objective: In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. Materials and Methods: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. Results: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. Conclusion: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

• Asian-Australasian Journal of Animal Sciences
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• 제20권10호
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• pp.1485-1489
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• 2007

Achaete-scute like 2 (ASCL2) gene encodes a member of the basic helix-loop-helix transcription factor which is essential for the maintenance of proliferating trophoblasts during placental development. ASCL2 gene preferentially expresses the maternal allele in the mouse. However, it escapes genomic imprinting in the human. In this study, the complete open reading frame consisting of 193 amino acids of ASCL2 gene was obtained. Sequence analysis indicated that a C-G mutation existed in the 3' region between Meishan and Large White pigs. The polymorphism was used to determine the monoallelic or biallelic expression with RT-PCR-RFLP in pigs of Large $White{\times}Meishan$ $F_1$ hybrids. Imprinting analysis indicated that the ASCL2 gene expression was biallelic in all the tested tissues (heart, liver, spleen, lung, kidney, stomach, small intestine, skeletal muscle, fat, uterus, ovary and pituitary). PCR-RFLP was used to detect the polymorphism in 270 pigs of the "$Large\;White{\times}Meishan$" $F_2$ resource population. The statistical results showed highly significant associations of the genotypes and fat meat percentage (FMP), lean meat percentage (LMP) and ratio of lean to fat (RLF) (p<0.01), and significant associations of the genotypes and loin eye area (LEA) and internal fat rate (IFR) (p<0.05).

• The Korean Journal of Physiology and Pharmacology
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• 제27권3호
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• pp.231-240
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• 2023

Fabry disease is a lysosomal storage disorder characterized by the lysosomal accumulations of glycosphingolipids in a variety of cytotypes, which include endothelial cells. The disease is inherited and originates from an error in glycosphingolipid catabolism caused by insufficient α-galactosidase A activity, which causes uncontrolled progressive storage of intracellular globotriaosylceramide (Gb3) in the vasculature and extracellular accumulation of lyso-Gb3 (a deacetylated soluble form of Gb3). Necrosis can lead to inflammation, which exacerbates necrosis and creates a positive feedback loop that triggers necroinflammation. However, the role played by necroptosis, a form of programmed necrotic cell death, in the cell-to-cell inflammatory reaction between epithelial and endothelial cells is unclear. Thus, the present study was undertaken to determine whether lyso-Gb3 induces necroptosis and whether necroptosis inhibition protects endothelial dysfunction against lyso-Gb3 inflamed retinal pigment epithelial cells. We found lyso-Gb3 induced necroptosis of a retinal pigment epithelial cell line (ARPE-19) in an autophagy-dependent manner and that conditioned media (CM) from ARPE-19 cells treated with lyso-Gb3 induced the necroptosis, inflammation, and senescence of human umbilical vein endothelial cells. In addition, a pharmacological study showed CM from lyso-Gb3 treated ARPE-19 cells induced endothelial necroptosis, inflammation, and senescence were significantly inhibited by an autophagy inhibitor (3-MA) and by two necroptosis inhibitors (necrostatin and GSK-872), respectively. These results demonstrate lyso-Gb3 induces necroptosis via autophagy and suggest that lyso-Gb3 inflamed retinal pigment epithelial cells trigger endothelial dysfunction via the autophagy-dependent necroptosis pathway. This study suggests the involvement of a novel autophagy-dependent necroptosis pathway in the regulation of endothelial dysfunction in Fabry disease.

• Journal of Power Electronics
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• 제15권6호
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• pp.1673-1681
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• 2015

A low dropout (LDO) regulator with a wide-bandwidth is proposed in this paper. The regulator features a Human Body Model (HBM) 8kV-class high robustness ElectroStatic Discharge (ESD) protection circuit, and two error amplifiers (one with low gain and wide bandwidth, and the other with high gain and narrow bandwidth). The dual error amplifiers are located within the feedback loop of the LDO regulator, and they selectively amplify the signal according to its ripples. The proposed LDO regulator is more efficient in its regulation process because of its selective amplification according to frequency and bandwidth. Furthermore, the proposed regulator has the same gain as a conventional LDO at 62 dB with a 130 kHz-wide bandwidth, which is approximately 3.5 times that of a conventional LDO. The proposed device presents a fast response with improved load and line regulation characteristics. In addition, to prevent an increase in the area of the circuit, a body-driven fabrication technique was used for the error amplifier and the pass transistor. The proposed LDO regulator has an input voltage range of 2.5 V to 4.5 V, and it provides a load current of 100 mA in an output voltage range of 1.2 V to 4.1 V. In addition, to prevent damage in the Integrated Circuit (IC) as a result of static electricity, the reliability of IC was improved by embedding a self-produced 8 kV-class (Chip level) ESD protection circuit of a P-substrate-Triggered Silicon Controlled Rectifier (PTSCR) type with high robustness characteristics.