• 제목/요약/키워드: far field

검색결과 1,919건 처리시간 0.029초

식품 중 식이섬유(Dietary fiber)의 의미와 기능성 고찰 -식이섬유의 특성과 기능을 중심으로- (Gerneral concept of dietary fiber and it's functionality)

  • 신동화
    • 식품과학과 산업
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    • 제52권1호
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    • pp.84-99
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    • 2019
  • Dietary fiber is defined as soluble and insoluble polysaccharide consisted in the plant cell wall-associated fibers naturally occurring in fruits, vegetables, and cereal products, and of isolated fibers that are added to processed foods which are also artificially modified. There are so many difference types of dietary fibers as arabinoxylan, polydextrose chicory, oligosccharide. inulin, pectin, bran, cellulose, ${\beta}$-glucan, resistant starch and some seaweed polymers as alginate. Most of them provide many biological benefits in the intestine, as lower risk for developing coronary heart disease, stroke, hypertension, diabetes, obesity and some of the gastrointestinal disease like as colon cancer. And also lowering cholesterol levels, improves glycemic and insulin sensitivity to non-diabetic and diabetic persons including immune system. Beside of many benefits, average consumers in developed and under developing countries take far less amounts of dietary fiber that international organization recommended. Adequate intake of dietary fiber is 14g/1,000kcal base using the energy guide line of 2,000kcal/day for women and 26,000 kcal/day for men, dietary intake is 28g/day of adult women and 36g/day for adult men. The mechanisms behind the reported effects of dietary fiber on metabolic health are not fully well established. It is suggested that changes in intestinal viscosity resulting mucus increasing, macro-nutrients absorption, rate of passage of large intestinal, production of short chain fatty acids by fermentation. Production of gut hormones and changes of microbiota in intestine. It is necessary to do more research in this field in the future and combined interdisciplinary works together.

Seismic investigation of pushover methods for concrete piers of curved bridges in plan

  • Ahmad, Hamid Reza;Namdari, Nariman;Cao, Maosen;Bayat, Mahmoud
    • Computers and Concrete
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    • 제23권1호
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    • pp.1-10
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    • 2019
  • The use of non-linear analysis of structures in a functional way for evaluating the structural seismic behavior has attracted the attention of the engineering community in recent years. The most commonly used functional method for analysis is a non-linear static method known as the "pushover method". In this study, for the first time, a cyclic pushover analysis with different loading protocols was used for seismic investigation of curved bridges. The finite element model of 8-span curved bridges in plan created by the ZEUS-NL software was used for evaluating different pushover methods. In order to identify the optimal loading protocol for use in astatic non-linear cyclic analysis of curved bridges, four loading protocols (suggested by valid references) were used. Along with cyclic analysis, conventional analysis as well as adaptive pushover analysis, with proven capabilities in seismic evaluation of buildings and bridges, have been studied. The non-linear incremental dynamic analysis (IDA) method has been used to examine and compare the results of pushover analyses. To conduct IDA, the time history of 20 far-field earthquake records was used and the 50% fractile values of the demand given the ground motion intensity were computed. After analysis, the base shear vs displacement at the top of the piers were drawn. Obtained graphs represented the ability of a cyclic pushover analysis to estimate seismic capacity of the concrete piers of curved bridges. Based on results, the cyclic pushover method with ISO loading protocol provided better results for evaluating the seismic investigation of concrete piers of curved bridges in plan.

DES와 FW-H 음향상사법을 이용한 탠덤 실린더의 공력소음 특성 연구 (A Numerical Study on Aerodynamic Noise Characteristics of the Tandem Cylinders using DES and FW-H Acoustic Analogy)

  • 김만식;이윤규
    • 한국항공우주학회지
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    • 제46권11호
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    • pp.883-891
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    • 2018
  • 본 연구에서는 항공기 랜딩 기어와 유사한 형태의 탠덤 실린더에 대해 DES (Detached Eddy Simulation)와 FW-H (Ffowcs Williams and Hawkings) 음향상사법을 이용한 전산공력 소음해석을 수행하였다. 실린더 중심 간 거리 3.7D 조건에 대한 전산공력소음해석 결과를 탠덤 실린더를 지나는 외부 유동 특성 및 원거리 소음을 계측한 선행 연구 결과와 비교하였다. 전방 실린더의 상/하부에서 발생한 와류(Vortex)가 특징적인 주파수를 갖고 후방 실린더에 충돌하면서 소음 발생원이 되는 것을 확인하였다. DES 와 FW-H 음향상사법을 이용한 전산공력소음해석 방법의 타당성을 확인한 후, 전방 실린더의 후방에 분할판을 적용한 경우의 전산공력소음해석을 수행하였다. 전방 실린더의 후방에 분할판이 적용되면 전방 실린더의 상/하부에서 발생하는 와류의 특징을 변화시키고 이극자 소음원 크기를 감소시켜 특정 주파수 대역에서 발생하는 소음 크기가 감소하는 것을 확인하였다.

The Standard Processing of a Time Series of Imaging Spectral Data Taken by the Fast Imaging Solar Spectrograph on the Goode Solar Telescope

  • Chae, Jongchul;Kang, Juhyeong;Cho, Kyuhyoun
    • 천문학회보
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    • 제43권2호
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    • pp.46.1-46.1
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    • 2018
  • The Fast Imaging Solar Spectrograph (FISS) on the Goode Solar Telescope (GST) at Big Bear Solar Observatory is the imaging Echelle spectrograph developed by the Solar Astronomy Group of Seoul National University and the Solar and Space Weather Group of Korea Astronomy and Space Science Institute. The instrument takes spectral data from a region on the Sun in two spectral bands simultaneously. The imaging is done by the organization of intensity data obtained from the fast raster scan of the slit over the field of view. Since the scan repeats many times, the whole set of data can be used to construct the movies of monochromatic intensity at arbitrary wavelengths within the spectral bands, and those of line-of-sight velocity inferred from different spectral lines. So far there are two standard observing configurations: one recording the $H{\alpha}$ line and the Ca II 8542 line simultaneously, and the other recording the Na I D2 line and Fe I 5435 line simultaneously. We have developed the procedures to produce the standard data for each observing configuration. The procedures include the spatial alignment, the correction of spectral shift of instrumental origin, and the lambdameter measurement of the line wavelength. The standard data include the movie of continuum intensity, the movies of intensity and velocity inferred from a chromospheric spectral line, the movies of intensity and velocity inferred from a photospheric line. The processed standard data will be freely available online (fiss.snu.ac.kr) to be used for research and public outreach. Moreover, the IDL procedures will be provided on request as well so that each researcher can adapt the programs for their own research.

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DEVELOPMENT TRENDS OF THE DIGITAL ECONOMY: E-BUSINESS, E-COMMERCE

  • Volkova, Nelia;Kuzmuk, Ihor;Oliinyk, Nataliia;Klymenko, Iryna;Dankanych, Andrii
    • International Journal of Computer Science & Network Security
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    • 제21권4호
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    • pp.186-198
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    • 2021
  • The introduction of digital technologies affects most socio-economic processes and activities in the economy, from agriculture to public services. Even though the world is currently only in the early stages of digital transformation, the digital economy is growing rapidly, especially in developing countries. Shortly, digital platforms will be able to replace the "invisible hand" of the market and turn it into digital. Some digital platforms have already reached global reach in some sectors of the economy. The growing value of data and artificial intelligence is reflected in the high capitalization of these enterprises. Their growing role has far-reaching consequences for the organization of economic activity and integration into the field of e-business. However, their importance and level of development in different countries differ significantly. The main purpose of this article is an assessment of the level and trends of the digital economy in the world and the identification of homogeneous groups of states following the main trends in the development of its components from among the EU countries. The methodology of the conducted research is based on the use of general scientific research methods in the analysis of secondary sources and the application of statistical methods of correlation-regression and cluster analysis. Macroeconomic indicators and components of DESI (Digital Economy and Society Index) were used for the analysis. Results. Based on the analysis established that most developed countries have a medium level of digitalization of the business environment and a high level of digitalization of socially oriented public services, while countries with lower GDP focus their policies on building digital infrastructure and training qualified personnel. The study summarizes and analyzes current trends in digital technology, analyzes the level and dynamics of integration of digital technologies of the studied EU countries, the level of development of e-business and e-commerce. The conceptualization of mechanisms of creation of added value in the digital economy is offered and the possible consequences of digitalization of the economy of developing countries are generalized.

감각-운동 중심의 융합 활동을 기초로 한 그룹 작업치료가 초등학교 1학년 부적응아동의 자기조절능력과 실행능력에 미치는 영향: 사례연구 (The Effect of Group Occupational Therapy based on Sensory-Motor Centered Convergence Activities on Self-regulation and Executive Function of Maladapted Children in First Grade Elementary School: A Case Study)

  • 조선영
    • 한국융합학회논문지
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    • 제12권2호
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    • pp.67-75
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    • 2021
  • 본 연구는 초등학교 1학년 부적응 아동을 대상으로 감각과 운동 중심의 융합 활동으로 구성 된 그룹 작업치료 프로그램을 실시하여 자기조절능력, 실행 기능에 미치는 영향을 알아보고자 하였다. 연구 설계는 사전-사후 검사를 통한 사례 연구이며 대상자는 총 3명이다. 사전-사후 검사로 자기 조절 능력 척도와 실행 기능을 알아보기 위해서 운동적 합성 검사를 실시하였다. 감각-운동 중심의 그룹 작업치료 프로그램은 전정 감각, 고유 감각, 촉각이 기초 한 움직임 활동을 하였으며 아동의 활동에 대한 선호도를 조사하여 과제를 선정하였다. 그 결과 대상자 1과 대상자 2 아동은 자기조절 능력, 실행 기능의 향상이 나타났다. 본 연구의 결과를 근거로 하여 교육 현장과 임상이 연계되어 학교의 부적응을 보이는 아동들에게 그룹 중심의 감각-운동 프로그램을 제공하여 학교의 적응 능력 향상을 기대할 수 있을 것을 사료된다.

Stochastic analysis of the rocking vulnerability of irregular anchored rigid bodies: application to soils of Mexico City

  • Ramos, Salvador;Arredondo, Cesar;Reinoso, Eduardo;Leonardo-Suarez, Miguel;Torres, Marco A.
    • Earthquakes and Structures
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    • 제20권1호
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    • pp.71-86
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    • 2021
  • This paper focuses on the development and assessment of the expected damage for the rocking response of rigid anchored blocks, with irregular geometry and non-uniform mass distribution, considering the site conditions and the seismicity of Mexico City. The non-linear behavior of the restrainers is incorporated to evaluate the pure tension and tension-shear failure mechanisms. A probabilistic framework is performed covering a wide range of block sizes, slenderness ratios and eccentricities using physics-based ground motion simulation. In order to incorporate the uncertainties related to the propagation of far-field earthquakes with a significant contribution to the seismic hazard at study sites, it was simulated a set of scenarios using a stochastic summation methods of small-earthquakes records, considered as Empirical Green's Function (EGFs). As Engineering Demand Parameter (EDP), the absolute value of the maximum block rotation normalized by the body slenderness, as a function of the peak ground acceleration (PGA) is adopted. The results show that anchorages are more efficient for blocks with slenderness ratio between two and three, while slenderness above four provide a better stability when they are not restrained. Besides, there is a range of peak intensities where anchored blocks located in soft soils are less vulnerable with respect to those located in firm soils. The procedure used in here allows to take decisions about risk, reliability and resilience assessment of different types of contents, and it is easily adaptable to other seismic environments.

컨벡스 프로그래밍을 이용한 추진-활공 유도탄의 중기궤적 최적화 (Mid-course Trajectory Optimization for Boost-Glide Missiles Based on Convex Programming)

  • 권혁훈;홍성민;김경훈;김윤환
    • 한국항공우주학회지
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    • 제49권1호
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    • pp.21-30
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    • 2021
  • 탐색기를 탑재한 유도탄의 중기궤적은 탐색기 시야(FOV : Field-Of-View) 내에서 표적을 탐지하며, 전환 시점에서의 기동성을 최대화하도록 설계하는 것이 요구된다. 유도탄의 비행궤적 최적화 문제는 여러 구속조건이 적용된 비선형 문제로 일반적인 해석해를 도출하기 어렵기 때문에 그 동안 다양한 계산적인 방법들이 제시되어 왔다. 본 논문에서는 추진-활공 유도탄의 중기궤적 최적화 문제를 컨벡스 최적화 기법인 2차 원뿔 프로그래밍을 이용하여 산출하였다. 먼저, 운동방정식의 상태변수를 최소화하기 위해서 제어변수 구속조건이 추가된 제어변수 추가 형태의 운동방정식을 구성하였다. 또한, 자유 종말시간 문제와 추진시간 문제를 대처하기 위하여 정규화된 시간 변수를 독립 변수로 설정하였다. 그리고, 운동방정식과 제어변수 구속조건을 컨벡스 형태로 변환하기 위하여 각각 부분 선형화와 무손실 컨벡스 변환을 적용하였다. 마지막으로, 본 논문에서 제시된 방안의 타당성을 확인하기 위하여 비선형 최적화 프로그래밍 결과와 비교하였다.

초중등학생 정보 교과 역량 검사 도구 개발 (Development of Information Competency Test Tool for Elementary and High School Students)

  • 홍지연;박정호
    • 한국정보통신학회논문지
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    • 제26권4호
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    • pp.605-611
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    • 2022
  • 4차 산업 혁명의 영향으로 미래 사회에 대비한 인재를 육성하기 위해 컴퓨팅 사고력을 기반으로 하는 역량 증진이 지속적으로 강조되고 있고 이에 우리나라에서도 2018년부터 SW교육을 의무로 실시하고 있다. 이에 따라 2017년부터 SW교육 역량 정의 및 진단 도구개발에 관한 연구가 진행되었으며 이때 개발된 중학생용 진단 도구를 2018년 한차례 수정 보완하여 지금까지 사용하고 있다. 이에 중학생만을 대상으로 하는 정보 교과 역량 검사를 초등학생과 고등학생을 대상까지 확대하고자 하는 현장의 요청에 의해 2019년 SW교육 선도학교 효과성 연구의 하나로 본 연구가 시작되었다. 본 연구에서는 중학생용 진단 도구를 기준으로 초등학생과 고등학생을 위한 진단 도구를 개발하고, 전문가 타당도 검증 및 예비검사를 실시한다. 예비검사를 통해 문항의 신뢰도, 변별도, 난이도 등을 분석하여 향후 초등학생과 고등학생을 대상으로 하는 검사 도구로서 가능성을 살펴볼 수 있을 것으로 기대한다.

A Study on Applying PID Control to a Downdraft Fixed Bed Gasifier using Wood Pellets

  • Park, Bu-Gae;Park, Seong-Mi;Park, Sung-Jun
    • 한국산업융합학회 논문집
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    • 제25권2_1호
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    • pp.149-159
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    • 2022
  • Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.