• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.334-339
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• 2015

Terabit-per-second (Tb/s) transmission capacity for the next generation of long-haul communication networks can be achieved using multicarrier optical super-channel technology. In an elastic orthogonal frequency division multiplexing (OFDM) super-channel transmission system, demultiplexing a portion of an entire spectrum in the form of a subband with minimum power is critically required. A major obstacle to achieving this goal is the analog-to-digital converter (ADC), which is power-hungry and extremely expensive. Without a proper ADC that can work with low power, it is unrealistic to design a 100G coherent receiver suitable for a commercially deployable optical network. Discrete Fourier transform (DFT) is often seen as a primary technique for understanding partial demultiplexing, which can be attained either optically or electronically. If fairly comparable performance can be achieved with an all-optical DFT circuit, then a solution independent of data rate and modulation format can be obtained. In this paper, we investigate two distinct OFDM super-channel receiver models, based on electronic and all-optical DFT-technologies, for partial carrier demultiplexing in a multi-Tb/s transmission system. The performance comparison of the receivers is discussed in terms of bit-error-rate (BER) performance.

• 한국공간구조학회논문집
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• 제19권4호
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• pp.45-52
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• 2019

The purpose of the paper is to introduce a system that reduces the occurrence of weak-story in the event of earthquake. Weak-story concentrates deformation on the story and causes all member to collapse before the capacity of all member is reached. This paper introduces Strong-Back system (SB) to protect weak story. SB is a hybrid of zipper frame, tied eccentrically braced frame, and elastic truss system and it is divided into elastic and inelastic areas. Elastic areas prevent the generation of weak story by distributing energy, and inelastic areas dissipate energy through buckling or yielding. In this paper, the seismic performance is evaluated by comparing the four type braced frame with SB through push-over analysis. The four criteria are compared from the base shear, the ductility capacity, the column failure order, and the quantity of brace. As a result, SB proved to have sufficient performance to protect the weak-story.

• 융합보안논문지
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• 제19권4호
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• pp.35-41
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• 2019

북한의 전략을 고려할 때, 개전 상황시 북한의 최우선 타격 목표는 공군을 무력화하는 공군 활주로일 가능성이 높다. 이에 대한 대응 방안으로 비상 활주로와 활주로 긴급 복구 작전이 있다. 하지만 비상 활주로는 주로 비상 착륙, 연료 공급, 재무장로 이용된다. 활주로 긴급 복구 작전도 북한의 위협적인 미사일 수준을 고려할 때 복구 시간 등 몇 가지 한계점이 있기에 활주로 폭파에 신속히 대응할 수가 없다. 본 연구에서는 먼저 북한의 미사일 위협 수준을 판단한다. 이후, 활주로 폭파의 차세대 대응방안인 이동식 활주로의 개념과 한계를 제시하며 기존 대응 방안과의 비교를 통해 이동식 활주로 도입의 필요성을 제시한다.

• 한국분무공학회지
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• 제19권4호
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• pp.204-210
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• 2014

Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.

• 한국지능시스템학회논문지
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• 제19권4호
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• pp.580-585
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• 2009

본 논문은 영상처리에 사용되는 코너점 추출을 위한 GP(Genetic Programming)기반의 코너 검출자를 소개한다. Harris와 SUSAN등 기존의 대표적인 코너 검출자들이 소개되어 왔고, 여러 가지 경험적인 알고리즘들이 연산 시간과 정확도 측면에서 이들 기법을 개선하기 위해서 연구되어 오고 있다. 이들 기법들은 코너점에 대한 특성을 고찰하여 이를 알고리즘화한 것으로 효율성이 높으나, 한편으로 기존의 방식이나 알고리즘에서 크게 벗어난 혁신적인 알고리즘을 발견하기에는 한계가 있다. 본 연구에서는 GP의 진화연산에 의해 자동적으로 코너 검출자를 생성함으로서 새로운 기법의 가능성을 발견하고자 한다. 제안된 방법을 다른 코너 검출자들과 테스트영상을 통해 비교 분석 하였다.

• 한국유체기계학회 논문집
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• 제19권4호
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• pp.54-62
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• 2016

This study presents an approach of tidal farming optimization using a numerical modelling method to simulate tidal energy extraction for 1MW scale tidal stream devices around Jangjuk-sudo, South Korea. The utility of the approach in this research is demonstrated by optimizing the tidal farm in an idealized scenario and a more realistic case with three scenarios of 28-turbine centered tidal array (named A, B and C layouts) inside the Jangjuk-sudo. In addition, the numerical method also provides a pre-processing calculation helps the researchers to quickly determine where the best resource site is located when considering the position of the tidal stream turbine farm. From the simulation results, it is clearly seen that the net energy (or wake energy yield which includes the impacts of wake effects on power generation) extracted from the layout A is virtually equal to the estimates of speed-up energy yield (or the gross energy which is the sum of energy yield of each turbine without wake effects), up to 30.3 GWh/year.

• Preventive Nutrition and Food Science
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• 제19권4호
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• pp.261-267
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• 2014

As a part of ongoing research to elucidate and characterize antioxidant and anti-inflammatory nutraceuticals, solvent-partitioned fractions from Spergularia marina were tested for their ability to scavenge radicals and suppress inflammation. The results of the 2',7'-dichlorofluorescein diacetate assay indicate that solvent-partitioned fractions from S. marina scavenged intracellular radicals in $H_2O_2$-stimulated mouse macrophages. The tested fractions decreased the generation of nitric oxide (NO) and the expression of inflammation mediators, namely, inducible nitric oxide synthase (iNOS) and interleukin (IL)-6, by lipopolysaccharide (LPS)-induced mouse macrophages, indicating that S. marina decreases inflammation. Among all tested fractions [i.e., $H_2O$, n-buthanol (n-BuOH), 85% aqueous methanol (aq. MeOH), and n-hexane], the 85% aq. MeOH fraction showed the strongest antioxidant and anti-inflammatory response. The 85% aq. MeOH fraction scavenged 80% of the free radicals produced by $H_2O_2$-induced control cells. In addition, NO production was 98% lower in 85% aq. MeOH fraction-treated cells compared to LPS-induced control cells. The mRNA expression of iNOS and IL-6 was also suppressed in 85% aq. MeOH fraction-treated cells. The results of the current study suggest that the phenolic compound components of S. marina are responsible for its antioxidant and anti-inflammatory effects.

• 대한안전경영과학회지
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• 제19권4호
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• pp.149-155
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• 2017

This study is analyzed combustion phenomena based on the environmental energy facility incinerator. It is assumed that combustible components of waste are composed of carbon and hydrogen, and the combustion process of fuel is by setting as multi-component / multistage reaction. As the combustion chamber is burned, the high temperature environment is achieved, also the heat transfer accompanied by the turbulent flow and the generation of NOx, a pollutant, are interpreted to predict the thermal and fluid characteristics and pollution emissions of the grate incinerator. As the result of internal flow analysis, the slow flow around the ash chute and the mixing effect due to the complicated turbulence around the combustion chamber were predicted to show excellent performance. It is shown to the internal average temperature was about $1024^{\circ}C$, around the about $1000^{\circ}C$ homogeneous temperature distribution. Due to the sudden temperature decrease in the boiler, the flue gas temperature at the outlet was estimated to be about $220^{\circ}C$.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.97-103
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• 2022

Low fertility rates and increased life expectancy further exacerbate the process of an aging society. This is also reflected in the gradual increase in the proportion of vulnerable groups in the social population. The demand for improved mobility among vulnerable groups such as the elderly or the disabled has greatly driven the growth of the electric-assisted mobility device market. However, such mobile devices generally require a certain operating capability, which limits the range of vulnerable groups who can use the device and increases the cost of learning. Therefore, autonomous driving technology needs to be introduced to make mobility easier for a wider range of vulnerable groups to meet their needs of work and leisure in different environments. This study uses mini PC Odyssey, Velodyne Lidar VLP-16, electronic device and Linux-based ROS program to realize the functions of working environment recognition, simultaneous localization, map generation and navigation of electric powered mobile devices for vulnerable groups. This autonomous driving mobility device is expected to be of great help to the vulnerable who lack the immediate response in dangerous situations.

• 식품보건융합연구
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• 제9권4호
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• pp.19-23
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• 2023

The integration of ChatGPT, an AI-powered language model, is causing a profound transformation within the food industry, impacting various domains. It offers novel capabilities in recipe creation, personalized dining, menu development, food safety, customer service, and culinary education. ChatGPT's vast culinary dataset analysis aids chefs in pushing flavor boundaries through innovative ingredient combinations. Its personalization potential caters to dietary preferences and cultural nuances, democratizing culinary knowledge. It functions as a virtual mentor, empowering enthusiasts to experiment creatively. For personalized dining, ChatGPT's language understanding enables customer interaction, dish recommendations based on preferences. In menu development, data-driven insights identify culinary trends, guiding chefs in crafting menus aligned with evolving tastes. It suggests inventive ingredient pairings, fostering innovation and inclusivity. AI-driven data analysis contributes to quality control, ensuring consistent taste and texture. Food writing and marketing benefit from ChatGPT's content generation, adapting to diverse strategies and consumer preferences. AI-powered chatbots revolutionize customer service, improving ordering experiences, and post-purchase engagement. In culinary education, ChatGPT acts as a virtual mentor, guiding learners through techniques and history. In food safety, data analysis prevents contamination and ensures compliance. Overall, ChatGPT reshapes the industry by uniting AI's analytics with culinary expertise, enhancing innovation, inclusivity, and efficiency in gastronomy.