• Title/Summary/Keyword: 주기적 경계 조건

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Decision-making system for the resource forecasting and risk management using regression algorithms (회귀알고리즘을 이용한 자원예측 및 위험관리를 위한 의사결정 시스템)

  • Han, Hyung-Chul;Jung, Jae-Hun;Kim, Sin-Ryeong;Kim, Young-Gon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.6
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    • pp.311-319
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    • 2015
  • In this paper, in order to increase the production efficiency of the industrial plant, and predicts the resources of the manufacturing process, we have proposed a decision-making system for resource implementing the risk management effectively forecasting and risk management. A variety of information that occurs at each step efficiently difficult the creation of detailed process steps in the scenario you want to manage, is a frequent condition change of manufacturing facilities for the production of various products even within the same process. The data that is not contiguous products production cycle also not constant occurs, there is a problem that needs to check the variation in the small amount of data. In order to solve these problems, data centralized manufacturing processes, process resource prediction, risk prediction, through a process current status monitoring, must allow action immediately when a problem occurs. In this paper, the range of change in the design drawing, resource prediction, a process completion date using a regression algorithm to derive the formula, classification tree technique was proposed decision system in three stages through the boundary value analysis.

Measurement and Prediction of 3-Dimensional Thermo-Mechanical Propertoes of Carbon-phenolic 8-harness Satin Weave Composites (탄소/페놀 8-매 주자직 복합재료의 3차원 열기계적 등가물성치에 관한 연구)

  • U,Gyeong-Sik;Kim,Pil-Jong;Yun,Gwang-Jun;Gu,Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.7
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    • pp.41-52
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    • 2003
  • In this paper, three-dimensional thermo-mechanical properties of carbon-phenolic 8-hamess satin weave composites were predicted considering geometric parameters of microstructures. The effective properties were calculated by a series of numerical experiments based on unit cell analysis. The microstructural details were modeled through macro-elements, and the periodic boundary conditions were derived for corresponding un it cell types. The Monte Carlo method was employed to consider the random phase shift between the layers, and the results were investigated on the effect of the geometric parameters of shift, number of layers and waviness ratios. Experimental tests were also performed and the results were compared.

Considerations and Alternative Approaches to the Estimation of Local Abundance of Legally Protected Species, the Fiddler Crab, Austruca lactea (법정보호종, 흰발농게(Austruca lactea) 서식 개체수 추정에 대한 검토와 대안)

  • Yoo, Jae-Won;Kim, Chang-Soo;Park, Mi-Ra;Jeong, Su-Young;Lee, Chae-Lin;Kim, Sungtae;Ahn, Dong-Sik;Lee, Chang-Gun;Han, Donguk;Back, Yonghae;Park, Young Cheol
    • Journal of Wetlands Research
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    • v.23 no.2
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    • pp.122-132
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    • 2021
  • We reviewed the methods employed in Korean tidal flat surveys to measure the local abundance of the endangered wildlife and marine protected species, the fiddler crab, Austruca lactea. A complete census for infinite population is impossible even in a limited habitat within a tidal flat, and density estimates from samples strongly vary due to diverse biological and ecological factors. The habitat boundaries and areas shift with periodicities or rhythmic activities of organisms as well as measurement errors. Hence the local abundance calculated from density and habitat areas should be regarded as transient. This conjecture was valid based on the spatio-temporal variations of the density averages, standard error ranges, and spatial distribution of the crab, A. lactea observed for 3 years (2015-2017) in Songdo tidal flat in Incheon. We proposed the potential habitat areas using the occurrence probability of 50% from logistic regression model, reflecting the importance of habitat conservation value as an alternative to local abundance. The spatial shape of potential habitat predicted from a generalized model would remain constant over time unless the species' critical environmental conditions change rapidly. The species-specific model is expected to be used for the introduction of desired species in future habitat restoration/creation projects.

Finite Element Modeling for the Analysis of In- and Out-of-plane Bulk Elastic Wave Propagation in Piezoelectric Band Gap Structures (압전 밴드 갭 구조물의 면내·외 방향 체적 탄성파 전파 특성 해석을 위한 유한요소 모델링)

  • Kim, Jae-Eun;Kim, Yoon-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.8
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    • pp.957-964
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    • 2011
  • This investigation presents a finite element method to obtain the transmission properties of bulk elastic waves in piezoelectric band gap structures(phonon crystals) for varying frequencies and modes. To this end, periodic boundary conditions are imposed on a three-dimensional model while both in-plane and out-of-plane modes are included. In particular, the mode decoupling characteristics between in-plane and out-of-plane modes are identified for each electric poling direction and the results are incorporated in the finite element modeling. Through numerical simulations, the proposed modeling method was found to be a useful, effective one for analyzing the wave characteristics of various types of piezoelectric phononic band gap structures.

Development of Multiple Regression Models for the Prediction of Daily Ammonia Nitrogen Concentrations (일별 암모니아성 질소(NH3-N)농도 예측을 위한 다중회귀모형 개발)

  • Chug, Se-Woong
    • Journal of Korea Water Resources Association
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    • v.36 no.6
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    • pp.1047-1058
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    • 2003
  • Seasonal occurrence of high ammonia nitrogen(NH3-N) concentrations has hampered chemical treatment processes of a water plant that intakes water at Buyeo site of Geum river. Thus it is often needed to quantify the effect of Daecheong Dam ouflow on the mitigation of $NH_3$-N contamination. In this study, multiple regression models were developed for forecasting daily $NH_3$-N concentrations using 8 years of water quality and dam outflow data, and verified with another 2 years of data set. During model development, the coefficients of determination($R^2$) and model efficiency($E_{m}$) were greater than 0.95. The verification results were also satisfactory although those statistical indices were slightly reduced to 0.84∼0.94 and 0.77∼0.93, respectively. The validated model was applied to assess the effect of different amounts of dam outflow on the reduction of $NH_3$-N concentrations in 2002. The NH3-N concentrations dropped by 0.332∼0.583 mg/L on average during January∼March as outflow increases from 5 to 50cms, and was most significant on February. The results of this research show that the multiple regression approach has potential for efficient cause and effect analysis between dam outflow and downstream water quality.

The Study on New Radiating Structure with Multi-Layered Two-Dimensional Metallic Disk Array for Shaping flat-Topped Element Pattern (구형 빔 패턴 형성을 위한 다층 이차원 원형 도체 배열을 갖는 새로운 방사 구조에 대한 연구)

  • 엄순영;스코벨레프;전순익;최재익;박한규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.7
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    • pp.667-678
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    • 2002
  • In this paper, a new radiating structure with a multi-layered two-dimensional metallic disk array was proposed for shaping the flat-topped element pattern. It is an infinite periodic planar array structure with metallic disks finitely stacked above the radiating circular waveguide apertures. The theoretical analysis was in detail performed using rigid full-wave analysis, and was based on modal representations for the fields in the partial regions of the array structure and for the currents on the metallic disks. The final system of linear algebraic equations was derived using the orthogonal property of vector wave functions, mode-matching method, boundary conditions and Galerkin's method, and also their unknown modal coefficients needed for calculation of the array characteristics were determined by Gauss elimination method. The application of the algorithm was demonstrated in an array design for shaping the flat-topped element patterns of $\pm$20$^{\circ}$ beam width in Ka-band. The optimal design parameters normalized by a wavelength for general applications are presented, which are obtained through optimization process on the basis of simulation and design experience. A Ka-band experimental breadboard with symmetric nineteen elements was fabricated to compare simulation results with experimental results. The metallic disks array structure stacked above the radiating circular waveguide apertures was realized using ion-beam deposition method on thin polymer films. It was shown that the calculated and measured element patterns of the breadboard were in very close agreement within the beam scanning range. The result analysis for side lobe and grating lobe was done, and also a blindness phenomenon was discussed, which may cause by multi-layered metallic disk structure at the broadside. Input VSWR of the breadboard was less than 1.14, and its gains measured at 29.0 GHz. 29.5 GHz and 30 GHz were 10.2 dB, 10.0 dB and 10.7 dB, respectively. The experimental and simulation results showed that the proposed multi-layered metallic disk array structure could shape the efficient flat-topped element pattern.

A Review on Monitoring Mt. Baekdu Volcano Using Space-based Remote Sensing Observations (인공위성 원격탐사를 이용한 백두산 화산 감시 연구 리뷰)

  • Hong, Sang-Hoon;Jang, Min-Jung;Jung, Seong-Woo;Park, Seo-Woo
    • Korean Journal of Remote Sensing
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    • v.34 no.6_4
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    • pp.1503-1517
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    • 2018
  • Mt. Baekdu is a stratovolcano located at the border between China and North Korea and is known to have formed through its differentiation stage after the Oligocene epoch in the Cenozoic era. There has been a growing interest in the magma re-activity of Mt. Baekdu volcano since 2010. Several research projects have been conducted by government such as Korea Meteorological Administration and Korea Institute of Geoscience and Mineral Resources. Because, however, the Mt. Baekdu volcano is located far from South Korea, it is quite difficult to collect in-situ observations by terrestrial equipment. Remote sensing is a science to analyze and interpret information without direct physical contact with a target object. Various types of platform such as automobile, unmanned aerial vehicle, aircraft and satellite can be used for carrying a payload. In the past several decades, numerous volcanic studies have been conducted by remotely sensed observations using wide spectrum of wavelength channels in electromagnetic waves. In particular, radar remote sensing has been widely used for volcano monitoring in that microwave channel can gather surface's information without less limitation like day and night or weather condition. Radar interferometric technique which utilized phase information of radar signal enables to estimate surface displacement such as volcano, earthquake, ground subsidence or glacial movement, etc. In 2018, long-term research project for collaborative observation for Mt. Baekdu volcano between Korea and China were selected by Korea government. A volcanic specialized research center has been established by the selected project. The purpose of this paper is to introduce about remote sensing techniques for volcano monitoring and to review selected studies with remote sensing techniques to monitor Mt. Baekdu volcano. The acquisition status of the archived observations of six synthetic aperture radar satellites which are in orbit now was investigated for application of radar interferometry to monitor Mt. Baekdu volcano. We will conduct a time-series analysis using collected synthetic aperture radar images.

Dynamics of Barrel-Shaped Young Supernova Remnants (항아리 형태 젊은 초신성 잔해의 동력학)

  • Choe, Seung-Urn;Jung, Hyun-Chul
    • Journal of the Korean earth science society
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    • v.23 no.4
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    • pp.357-368
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    • 2002
  • In this study we have tried to explain the barrel-shaped morphology for young supernova remnants considering the dynamical effects of the ejecta. We consider the magnetic field amplification resulting from the Rayleigh-Taylor instability near the contact discontinuity. We can generate the synthetic radio image assuming the cosmic-ray pressure and calculate the azimuthal intensity ratio (A) to enable a quantitative comparison with observations. The postshock magnetic field are amplified by shearing, stretching, and compressing at the R-T finger boundary. The evolution of the instability strongly depends on the deceleration of the ejecta and the evolutionary stage of the remnant. the strength of the magnetic field increases in the initial phase and decreases after the reverse shock passes the constant density region of the ejecta. However, some memory of the earlier phases of amplification is retained in the interior even when the outer regions turn into a blast wave. The ratio of the averaged magnetic field strength at the equator to the one at the pole in the turbulent region can amount to 7.5 at the peak. The magnetic field amplification can make the large azimuthal intensity ratio (A=15). The magnitude of the amplification is sensitive to numerical resolution. This mens the magnetic field amplification can explain the barrel-shaped morphology of young supernova remnant without the dependence of the efficiency of the cosmic-ray acceleration on the magnetic field configuration. In order for this mechanism to be effective, the surrounding magnetic field must be well-ordered. The small number of barrel-shaped remnants may indicate that this condition rarely occurs.

Zwei Perspektiven für die Kunst - Kants Ästhethik des Empfangenden und Nietzsches Physiologie der Kunst - (예술에 대한 두 가지 태도 - 칸트의 수용미학과 니체의 예술생리학 -)

  • Chung, Nak-rim
    • Journal of Korean Philosophical Society
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    • v.130
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    • pp.277-304
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    • 2014
  • Der vorliegende Beitrag zielt darauft ab, zwei Perspektiven $f{\ddot{u}}r$ die Kunst bei Kant und Nietzsche und ihre Schlussfolgerungen zu $er{\ddot{o}}rtern$. Kants Kritik der Urteilskraft hat eine enorme Rolle in der Geschichte der ${\ddot{A}}sthetik$ gespielt. $F{\ddot{u}}r$ Kant sollen ${\ddot{a}}sthetische$ Urteile ebenso wie Erkenntnis- und Moralurteile $allgemeing{\ddot{u}}ltig$ sein, obwohl sie auf einem $pers{\ddot{o}}nlichen$ Geschmack beruhen. Die $Allgemeing{\ddot{u}}ltigkeit$ des $Sch{\ddot{o}}nen$ sei $m{\ddot{o}}glich$, weil sie nicht auf dem Gegenstand, sondern auf dem transzendentalen Subjekt basiere. Die $sch{\ddot{o}}ne$ Kunst als Kunst des Genies soll uns wie die $Natursch{\ddot{o}}nheit$ ohne Interesse wohlgefallen. Nietzsches Stellungnahme zu Kants ${\ddot{A}}sthetik$ ist sehr kritisch. Nietzsches erster Kritikpunkt richtet sich gegen das 'interesselose Wohlgefallen'. Gegen Kant behauptet Nietzsche, dass die $Sch{\ddot{o}}nheit$ sehr wohl mit Interesse verbunden ist. Grund $daf{\ddot{u}}r$ ist, dass das $Sch{\ddot{o}}ne$ wesentlich aus dem Willen zur Macht entspringt. Der zweite Kritikpunk Nietzsches liegt darin, dass in Kants ${\ddot{A}}sthetik$ die Moral im Vordergrund steht. Das $Sch{\ddot{o}}ne$ ist $f{\ddot{u}}r$ Kant durch die Moral gerechtfertigt. Nietzsche dreht diese Stellung der Moral zur Kunst um. Der dritte Kritikpunkt Nietzsches ist, dass Kant statt von der Erfahrung des $K{\ddot{u}}nstlers$ (Schaffenden) aus das ${\ddot{a}}sthetische$ Problem zu betrachten, allein vom Zuschauer (Empfangenden) aus ${\ddot{u}}ber$ die Kunst und das $Sch{\ddot{o}}ne$ nachgedacht habe. $F{\ddot{u}}r$ Nietzsche ist die Kunst $prim{\ddot{a}}r$ vom $K{\ddot{u}}nstler$ aus zu verstehen. Nietzsches Physiologie der Kunst ist mit dem Begriff 'Leib' $verkn{\ddot{u}}pft$, d.h. Nietzsche behauptet, dass physiologische und ${\ddot{a}}sthetische$ Prozesse wesentlich $zusammenh{\ddot{a}}ngen$. Die Schlussfolgerung der Physiologie der Kunst lautet: erstens, jeder Mensch ist $K{\ddot{u}}nstler$, sofern er schaffend ist, und zweitens, die Welt selbst ist nichts als Kunst. Nietzsches Physiologie der Kunst hat einen $gro{\ss}en$ Einfluss auf die $gegenw{\ddot{a}}rtige$ Kunst $ausge{\ddot{u}}bt$ und kein anderer Philosoph hat auf die $gegenw{\ddot{a}}rtige$ Kunst nachaltiger gewirkt.

Effects of Ocean Outfall for Elimination of the Anoxic Layer in Youngsan River Estuary (영산강 하구언에서 저 산소 층의 제거를 위한 해양방류구의 효과)

  • Kwon, Seok-Jae;Cho, Yang-Ki;Seo, Uk-Won
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.17 no.4
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    • pp.259-268
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    • 2005
  • There has been a growing interest in the elimination of anoxic layer in the Youngsan River Estuarybecause the anoxic water mass caused mainly by the inflow of fresh water from the sea wall might cause the mass reduction of benthos during summer. An ocean outfall system to discharge treated wastewater into sea water may be used as one of the effective and economical ways to eliminate the anoxic layer. The suitable ocean outfall design is generally proposed for the prediction of the buoyant jet behavior in the near field. The parameters including CTD and current data are taken into account f3r more reliable buoyant jet behavior calculation. One of the numerical models, CORMIX 1, approved by EPA is used herein for the prediction of the trajectorial variation of the cross-sectional salinity and DO concentration distribution on the calculated buoyant jet boundary according to the tidal periods. On the basis of the results, it is suggested that the single port outfall is a useful system to eliminate the anoxic layer. Proper strategies are also proposed for achieving desirable ambient conditions.