• Computational Structural Engineering
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• v.9 no.2
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• pp.93-101
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• 1996

An artificial neural network is a computational model that mimics the biological system of the brain and it consists of a number of interconnected processing units where it can reasonably infer by them. Because the neural network is particularly useful for evaluating systems with a multitude of nonlinear variables, it can be used in experimental results predictions, in structural planning and in optimum design of structures. This paper describes the basic theory related to the neural networks and discusses the applicability of neural networks to predict the ultimate shear capacity of the precast concrete vertical joints by comparing the neural networks with a conventional method such as regression.

• Journal of the Semiconductor & Display Technology
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• v.8 no.1
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• pp.13-17
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• 2009

In PRAM applications, the devices can be made for both binary and multi-state storage. The ability to attain intermediate stages comes either from the fact that some chalcogenide materials can exist in configurations that range from completely amorphous to completely crystalline or from designing device structure such a way that mimics multiple phase chase phenomena in single cell. We have designed stack-structured phase change memory cell which operates as multi-state storage. Amorphous $Ge_xTe_{100-x}$ chalcogenide materials were stacked and a diffusion barrier was chosen for each stack layers. The device is operated by crystallizing each chalcogenide material as sequential manner from the bottom layer to the top layer. The amplitude of current pulse and the duration of pulse width was fixed and number of pulses were controlled to change overall resistance of the phase change memory cell. To optimize operational performance the thickness of each chalcogenide was controlled based on simulation results.

• Molecules and Cells
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• v.27 no.2
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• pp.243-250
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• 2009

Recent studies suggest a novel role of $HIF-1{\alpha}$ under nonhypoxic conditions, including antibacterial and antiviral innate immune responses. However, the identity of the pathogen-associated molecular pattern which triggers $HIF-1{\alpha}$ activation during the antiviral response remains to be identified. Here, we demonstrate that cellular administration of double-stranded nucleic acids, the molecular mimics of viral genomes, results in the induction of $HIF-1{\alpha}$ protein level as well as the increase in $HIF-1{\alpha}$ target gene expression. Whole-genome DNA microarray analysis revealed that double-stranded nucleic acid treatment triggers induction of a number of hypoxia-inducible genes, and induction of these genes are compromised upon siRNA-mediated $HIF-1{\alpha}$ knock-down. Interestingly, $HIF-1{\alpha}$ knock-down also resulted in down-regulation of a number of genes involved in antiviral innate immune responses. Our study demonstrates that $HIF-1{\alpha}$ activation upon nucleic acid-triggered antiviral innate immune responses plays an important role in regulation of genes involved in not only hypoxic response, but also immune response.

• Journal of Gastric Cancer
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• v.15 no.1
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• pp.68-73
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• 2015

Gastric cancer that mimics a submucosal tumor is rare. This rarity and the normal mucosa covering the protuberant tumor make it difficult to diagnosis with endoscopy. We report two cases of advanced gastric cancer that mimicked malignant gastrointestinal stromal tumors preoperatively. In both cases, the possibility of cancer was not completely ruled out. In the first case, a large tumor was suspected to be cancerous during surgery. Therefore, total gastrectomy with lymph node dissection was performed. In the second case, the first gross endoscopic finding was of a Borrmann type II advanced gastric cancer-like protruding mass with two ulcerous lesions invading the anterior wall of the body. Therefore, subtotal gastrectomy with lymph node dissection was performed. Consequently, delayed treatment of cancer was avoided in both cases. If differential diagnosis between malignant gastrointestinal stromal tumor and cancer is uncertain, a surgical approach should be carefully considered due to the possible risk of adenocarcinoma.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.39.3-39.3
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• 2010

Solar-terrestrial links in short-time scales(daily ~monthly) are extensively explored in recent years: such as a response of low cloud amounts to the Forbush decrease, a response of Northern Atlantic oscillation index to sudden increase in electric field intensity of solar wind and so on (e.g., Svensmark et al., 2009; Boberg & Lundstedt, 2002). In this study, we perform the superposed epoch analysis to see any possible response of the sea-level pressure over Korean peninsula to the fast solar wind stream. Data sets are daily values, and zero days are determined to be days when the solar wind velocity exceeds 800km/s. Average profile of superposed sea-level pressure shows a gradual increase during the first 2 days and a decrease afterward below the normal level with a low pressure condition maintained for a few days. This result indicates that the sea-level pressure may respond to the fast solar wind stream. In other words, the average profile of sea-level pressure mimics the average velocity profiles. The correlation coefficient between two average profiles is 0.80, with 2 day lag.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2184-2186
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• 2001

The research presented in this paper focuses on a method for the detection of High Impedance Fault(HIF). The method will use the fast wavelet transform and neural network system. HIF on the multi-grounded three-phase four-wires primary distribution power system cannot be detected effectively by existing over current sensing devices. These paper describes the application of fast wavelet transform to the various HIF data. These data were measured in actual 22.9kV distribution system. Wavelet transform analysis gives the frequency and time-scale information. The neural network system as a fault detector was trained to discriminate HIF from the normal status by a gradient descent method. The proposed method performed very well by proving the right state when it was applied staged fault data and normal load mimics HIF, such as arc-welder.

• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.987-997
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• 2012

The sales volume of men's cosmetics has drastically increased in Korea. In recent years, men's needs for cosmetics have been diversified and the consumer demand for functional cosmetics has greatly risen. In particular, male consumers have become more interested in essence product that is a light and concentrated treatment to correct skin problems. This research analyzes consumer preferences for essence-for-men through the use of choice-based conjoint analysis. This approach is adopted since the task of respondents to choose the most preferred option from several alternatives closely mimics actual marketplace purchasing behavior by consumers. New technique for the construction of choice sets is suggested based on the balanced incomplete block design, to accommodate a larger number of product profiles. The proposed design for choice sets is balanced and provides a tool to filter the contradictory choices. Conjoint analyses are performed to assess the relative importance of attributes and identify the most preferred profile of essence-for-men with respect to attributes such as emphasized function, price, type of content, and design of container. Some differences are indicated in the analysis results between age brackets as well as between groups classified by the amount of fashion item expenditures.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.251.2-251.2
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• 2013

Natural photosynthesis utilizes two proteins, photosystem I and photosystem II, to efficiently oxidize water and reduce NADP+ to NADPH. Artificial photosynthesis which mimics this process achieve water splitting through a two-step Z-schematic water splitting process using man-made synthetic materials for hydrogen fuel production. In this study, Z-scheme system was achieved from the hybrid materials which composed of hydrogen production part as photosystem I protein and water oxidizing part as semiconductor BiVO4. Utilizing photosystem I as the hydrogen evolving part overcomes the problems of existing hydrogen evolving p-type semiconductors such as water instability, expensive cost, few available choices and poor red light (>600 nm) absorbance. Some problems of photosystem II, oxygen evolving part of natural photosynthesis, such as demanding isolation process and D1 photo-damage can also be solved by utilizing BiVO4 as the oxygen evolving part. Preceding research has not suggested any protein-inorganic-hybrid Z-scheme composed of both materials from natural photosynthesis and artificial photosynthesis. In this study, to realize this Z-schematic electron transfer, diffusion step of electron carrier, which usually degrades natural photosynthesis efficiency, was eliminated. Instead, BiVO4 and Pt-photosystem I were all linked together by the mediator gold. Synthesized all-solid-state hybrid materials show enhanced hydrogen evolution ability directly from water when illuminated with visible light.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.1-7
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• 1998

Aqueous extract of Morus alba L. blocked the toxic effect of paraquat on E. coli growth. The active components in the extract may be capable of crossing the cell membranes and protect against superoxide toxicity in E. coli, The extract inhibited $FeSO_4/H_2O_2$ induced lipid peroxidation in rat liver homogenate and protected against t-butyl hydroperoxide caused Ac2F cell damage. Moreover, the extract showed inhibitory effect on phospholipase $A_2$ activity in a dose dependent manner. Antiinflammatory effect of the extract was further investigated using the carrageenin-induced oedema model. A single adminstration of the extract (3g/kg body, p.o.) was more effective than indomethacin. These results suggest that the isolation and identification of the active components would have significant therapeutic application to inflammation associated with oxygen radicals.

• Electronics and Telecommunications Trends
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• v.33 no.6
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• pp.58-68
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• 2018

A neuromorphic hardware that mimics biological perceptions and has a path toward human-level artificial intelligence (AI) was developed. In contrast with software-based AI using a conventional Von Neumann computer architecture, neuromorphic hardware-based AI has a power-efficient operation with simultaneous memorization and calculation, which is the operation method of the human brain. For an ideal neuromorphic device similar to the human brain, many technical huddles should be overcome; for example, new materials and structures for the synapses and neurons, an ultra-high density integration process, and neuromorphic modeling should be developed, and a better biological understanding of learning, memory, and cognition of the brain should be achieved. In this paper, studies attempting to overcome the limitations of next-generation neuromorphic hardware technologies are reviewed.