• Title/Summary/Keyword: Mathematical

Search Result 31,060, Processing Time 0.05 seconds

Development and Validation of Digital Twin for Analysis of Plant Factory Airflow (식물공장 기류해석을 위한 디지털트윈 개발 및 실증)

  • Jeong, Jin-Lip;Won, Bo-Young;Yoo, Ho-Dong;Kim, Tag Gon;Kang, Dae-Hyun;Hong, Kyung-Jin
    • Journal of the Korea Society for Simulation
    • /
    • v.31 no.1
    • /
    • pp.29-41
    • /
    • 2022
  • As one of the alternatives to solve the problem of unstable food supply and demand imbalance caused by abnormal climate change, the need for plant factories is increasing. Airflow in plant factory is recognized as one of important factor of plant which influence transpiration and heat transfer. On the other hand, Digital Twin (DT) is getting attention as a means of providing various services that are impossible only with the real system by replicating the real system in the virtual world. This study aimed to develop a digital twin model for airflow prediction that can predict airflow in various situations by applying the concept of digital twin to a plant factory in operation. To this end, first, the mathematical formalism of the digital twin model for airflow analysis in plant factories is presented, and based on this, the information necessary for airflow prediction modeling of a plant factory in operation is specified. Then, the shape of the plant factory is implemented in CAD and the DT model is developed by combining the computational fluid dynamics (CFD) components for airflow behavior analysis. Finally, the DT model for high-accuracy airflow prediction is completed through the validation of the model and the machine learning-based calibration process by comparing the simulation analysis result of the DT model with the actual airflow value collected from the plant factory.

Development of Optimal Antiviral Coating Method for the Air Filtration System of Subway Station (지하역사 승강장 공조 시스템 필터용 항바이러스 코팅 성능 및 재생 성능 평가)

  • Park, Dae Hoon;Hwang, Jungho;Shin, Dongho;Kim, Younghun;Lee, Gunhee;Park, Inyong;Kim, Sang Bok;Hong, Keejung;Han, Bangwoo
    • Particle and aerosol research
    • /
    • v.18 no.1
    • /
    • pp.9-21
    • /
    • 2022
  • In this study, a novel antiviral coating method for the air filtration system of subway station was investigated. Using dry aerosol coating process, we developed a high-performance antiviral air filter with spark discharger and carbon brush type ionizer. Silver nanoparticles were produced by a spark discharge generation system with ion injection system and were used as antiviral agents coated onto a medium grade air filter. The pressure drop, filtration efficiency, and antiviral ability of the filter against aerosolized MS2 virus particles as a surrogate of SARS-CoV-2 virus were tested with dust contamination. Dust contamination caused the increase of the filtration efficiency and pressure drop, while the antiviral agents (in this study, silver nanoparticles) coating did not have any significant effect on the filtration efficiency and pressure drop. Using these properties, we suggested a novel method to maximize the antiviral performance of the antiviral air filter that was contaminated by dust particles. Moreover theoretical analysis of antiviral ability with dust contamination and re-coated antiviral agents was carried out using a mathematical model to calculate the time-dependent antiviral effect of the filter under actual conditions of subway station. Our model can be used to apply on antiviral air filtration system of subway station for prevention of pandemic diffusion, and predict the life cycle of an antiviral filter.

Approximate Analytical Formula for Minimum Principal Stress Satisfying the Generalized Hoek-Brown Failure Criterion (일반화된 Hoek-Brown 파괴기준식을 만족하는 최소주응력의 해석적 근사식)

  • Lee, Youn-Kyou
    • Tunnel and Underground Space
    • /
    • v.31 no.6
    • /
    • pp.480-493
    • /
    • 2021
  • Since the generalized Hoek-Brown criterion (GHB) provides an efficient way of identifying its strength parameter values with the consideration of in-situ rock mass condition via Geological Strength Index (GSI), this criterion is recognized as one of the standard rock mass failure criteria in rock mechanics community. However, the nonlinear form of the GHB criterion makes its mathematical treatment inconvenient and limits the scope of its application. As an effort to overcome this disadvantage of the GHB criterion, the explicit approximate analytical equations for the minimum principal stress, which is associated with the maximum principal stress at failure, are formulated based on the Taylor polynomial approximation of the original GHB criterion. The accuracy of the derived approximate formula for the minimum principal stress is verified by comparing the resulting approximate minimum principal stress with the numerically calculated exact values. To provide an application example of the approximate formulation, the equivalent friction angle and cohesion for the expected plastic zone around a circular tunnel in a GHB rock mass are calculated by incorporating the formula for the approximate minimum principal stress. It is found that the simultaneous consideration of the values of mi, GSI and far-field stress is important for the accurate calculation of equivalent Mohr-Coulomb parameter values of the plastic zone.

A Study on the Conservation of Biodiversity by the Ecological Economic Numerical Model (생태경제수치모형에 의한 생물다양성 보존에 관한 연구)

  • Kim, Byung-Nam
    • The Journal of the Korea Contents Association
    • /
    • v.22 no.6
    • /
    • pp.629-637
    • /
    • 2022
  • It is at risk of depletion of biodiversity due to indiscriminate overfishing of ecosystems and destruction of habitats. Intensive fertilizers or development of related facilities to increase agricultural production in poor indigenous areas devastate the soil. Preservation of biodiversity is now emerging as an important issue of global human coexistence. After the Post-2020 GBF Declaration, all governance in agricultural development in indigenous agricultural areas should be supported and promoted as biodiversity conservation measures. A compromise plan to reduce ecosystem development and biodiversity loss can help establish public governance policies. In this paper, a viability kernel used for viable control feedback analysis is introduced to solve conflicting economic and ecological problems in ecosystem conservation, and a mathematical model on biodiversity conservation by the viability kernel is examined. Because all species in the ecosystem are interdependent, if the balance is broken, biodiversity is depleted, which is irreversible and eventually leads to extinction. For sustainable use and harmony of biological resources, a lot of policy consideration is required, such as creative governance that can efficiently protect all species. Subsidies or tax incentives have a direct impact on biodiversity conservation. The recovery of species in a state of decreasing biodiversity can be said to be of great economic value. Biodiversity will allow indigenous producers to be proud of their unique traditional knowledge and have a positive impact on local tourism, thereby enhancing regional identity and greatly contributing to the survival and prosperity of mankind.

A Study of Antiquity YulRyeo (고대(古代) 율려(律呂)에 관한 연구)

  • Choi, Won-Ho;Kim, Ki-Seung
    • Industry Promotion Research
    • /
    • v.7 no.1
    • /
    • pp.59-74
    • /
    • 2022
  • There are three main ways to interpret Zhouyi(周易). The first is to interpret it as a number, the second is to interpret it as an image symbolized by the Gwae(卦), and the third is to interpret it as the moral reason contained in it. Although YulRyeo(律呂) is not as widely known as Zhouyi, its use in ancient times was the same as that of the main character. First, the mathematical analysis method using the three-pronged method for tuning musical instruments, second, the symbolic interpretation using the musical meaning symbolized by YulRyeo, and third, the applied interpretation method that expands to the moral reason contained in YulRyeo. The purpose of this thesis is to organize the dictionary meaning of YulRyeo and various meanings of ancient YulRyeo. In addition, by studying ancient literature on the meaning of YulRyeo's magic spell mechanics(術數易學) and Naepeum and Five Elements(納音五行), which is the origin of Gobeop Myongriology, I classify and interpret them in detail. and to find ways to apply it to Myongriology. It is hoped that this study will give a more in-depth understanding of YulRyeo and will be of little help to related studies such as the mechanics of magic and Myongriology studies in the future.

The Characteristics of the Questions Presented in Shapes Area and Measurement Area of Elementary Mathematics Textbooks (초등수학 교과서의 도형 및 측정 영역에 제시된 발문의 특성)

  • Do, Joowon
    • Education of Primary School Mathematics
    • /
    • v.25 no.4
    • /
    • pp.313-328
    • /
    • 2022
  • The purpose of this study is to understand the characteristics of the questions presented in shapes area and Measurement area of elementary mathematics textbooks. For this purpose, the types of questions presented in shapes area and measurement area of elementary mathematics textbooks and their working functions were comparatively analyzed by area and by grade cluster. As a result of the analysis, the number of questions per lesson increased sharply in the 3rd and 4th grade cluster compared to the 1st and 2nd grade cluster in both shapes area and measurement area. In these two areas, the most common reasoning questions are presented. It is presented relatively more in measurement area than in shapes area. There was a clear difference between the types of questions presented in shapes area and measurement area. In common with the two areas, questions mainly were acted as a function to help students learn to reason mathematically, a function to help students to determine whether something is mathematically correct, and a function to help students learn to conjecture, invent, and solve problem. The characteristics of the questions identified in this study can provide teaching/learning implications for the design and application of the questions suitable for the guidance of shapes area and measurement area, and can be used as a reference material when writing mathematics textbooks.

The Geometrical Imagination of the MCU 'Phase 3' Movie (MCU '페이즈3'영화에 나타난 기하학적 상상력)

  • Kim, Young-Seon;Kim, Tae-Soo
    • The Journal of the Korea Contents Association
    • /
    • v.22 no.10
    • /
    • pp.132-142
    • /
    • 2022
  • The purpose of this study is to interpret the MCU's universal worldview from the perspective of geometry and to storytell narrative elements with mathematical imagination. For storytelling, data from the Phase 3 series aired from 2016 to 2019 was used. The Phase 3 series stimulates the imagination of the public with the sense of reality shown in the narrative and images based on geometrical theory and various predictions about future technology. Imagination is the driving force for diverse and original thinking about the unexperienced, and the ability to find order in chaos and create new perceptions of matter. The power of imagination is very necessary not only in artistic activities, but also in the scientific field where logic and rationality are important. Bachelard's imagination aims for art, the primitive realm of human beings, and contains sincerity and passion for the wonders of nature and all things. By exploring the MCU's worldview and superhero narrative through geometrical logic and imagination-driven imagery, you can understand the cosmic messages and laws in the film. From a convergence point of view of art and science, various and original techniques based on mathematics and scientific imagination used in MCU video production will help to improve the quality of video analysis.

On the Tensor Product of m-Partition Algebras

  • Kennedy, A. Joseph;Jaish, P.
    • Kyungpook Mathematical Journal
    • /
    • v.61 no.4
    • /
    • pp.679-710
    • /
    • 2021
  • We study the tensor product algebra Pk(x1) ⊗ Pk(x2) ⊗ ⋯ ⊗ Pk(xm), where Pk(x) is the partition algebra defined by Jones and Martin. We discuss the centralizer of this algebra and corresponding Schur-Weyl dualities and also index the inequivalent irreducible representations of the algebra Pk(x1) ⊗ Pk(x2) ⊗ ⋯ ⊗ Pk(xm) and compute their dimensions in the semisimple case. In addition, we describe the Bratteli diagrams and branching rules. Along with that, we have also constructed the RS correspondence for the tensor product of m-partition algebras which gives the bijection between the set of tensor product of m-partition diagram of Pk(n1) ⊗ Pk(n2) ⊗ ⋯ ⊗ Pk(nm) and the pairs of m-vacillating tableaux of shape [λ] ∈ Γkm, Γkm = {[λ] = (λ1, λ2, …, λm)|λi ∈ Γk, i ∈ {1, 2, …, m}} where Γk = {λi ⊢ t|0 ≤ t ≤ k}. Also, we provide proof of the identity $(n_1n_2{\cdots}n_m)^k={\sum}_{[{\lambda}]{\in}{\Lambda}^k_{{n_1},{n_2},{\ldots},{n_m}}}$ f[λ]mk[λ] where mk[λ] is the multiplicity of the irreducible representation of $S{_{n_1}}{\times}S{_{n_2}}{\times}....{\times}S{_{n_m}}$ module indexed by ${[{\lambda}]{\in}{\Lambda}^k_{{n_1},{n_2},{\ldots},{n_m}}}$, where f[λ] is the degree of the corresponding representation indexed by ${[{\lambda}]{\in}{\Lambda}^k_{{n_1},{n_2},{\ldots},{n_m}}}$ and ${[{\lambda}]{\in}{\Lambda}^k_{{n_1},{n_2},{\ldots},{n_m}}}=\{[{\lambda}]=({\lambda}_1,{\lambda}_2,{\ldots},{\lambda}_m){\mid}{\lambda}_i{\in}{\Lambda}^k_{n_i},i{\in}\{1,2,{\ldots},m\}\}$ where ${\Lambda}^k_{n_i}=\{{\mu}=({\mu}_1,{\mu}_2,{\ldots},{\mu}_t){\vdash}n_i{\mid}n_i-{\mu}_1{\leq}k\}$.

A Longitudinal Analysis of the Influence of Teachers' Achievement Pressure and Enthusiasm Perceived by Students on Academic Achievement in Mathematics: For Elementary and Middle School Students (학생들이 인지하는 교사의 성취압력과 열의가 수학 학업성취도에 미치는 영향력에 대한 종단적 분석: 초·중학생들을 대상으로)

  • Kim, YongSeok
    • Education of Primary School Mathematics
    • /
    • v.24 no.3
    • /
    • pp.135-156
    • /
    • 2021
  • Achievement pressure and enthusiasm affecting mathematics academic achievement are constantly changing and affecting academic achievement. Therefore, a longitudinal study is needed to examine the influence of the change patterns of teachers' achievement pressure and enthusiasm on the change patterns of academic achievement. This study utilized student data from the 5th grade of elementary school (2013 year) to the third grade of middle school (2017 year) of the Korean Education Longitudinal Study 2013. The longitudinal change patterns of mathematics academic achievement were classified into similar subgroups and the influence of the longitudinal change patterns of the achievement pressure and enthusiasm of each group on the longitudinal change pattern of mathematics academic achievement and the path were compared and analyzed. As a result of the analysis, in all four subgroups with similar longitudinal changes in mathematics academic achievement, the teacher's achievement pressure showed little change from the fifth grade, while the teacher's enthusiasm continued to decline from the fifth grade. In addition, the influence of teachers' achievement pressure and enthusiasm perceived by students in each group on mathematics academic achievement was different. This suggests that in order to improve mathematics academic achievement, it is necessary to support teaching and learning reflecting the characteristics and dispositions of students.

Assessment of a fresh submarine groundwater discharge in eastern Jeju Island using analytic seawater intrusion models (해수침투 해석해 기반 제주 동부 담해저 지하수 유출의 정량적 산정)

  • Kim, Il-Hwan;Chang, Sun Woo
    • Journal of Korea Water Resources Association
    • /
    • v.55 no.12
    • /
    • pp.1011-1020
    • /
    • 2022
  • Previous studies for the assessment of submarine groundwater discharge (SGD) were perfomed for areas where a large amount of SGD was observed. Newly developed assessment methods were proposed that was based on an analytic solution using sharp interface model. The proposed mathematical equations used the existing observed groundwater level and hydrogeological data of Jeju Island as input data. The quantitatively assessed FSGD values were compared to the basin-scale recharge estimation values in Seong-San area in eastern Jeju. As a result of the study, it was estimated that the amount of FSGD in the Seongsan area ranges from about 2.65 to 9.15% of the amount of areal-recharge. Through the analysis of the FSGD combined with the analytic model, it is to be provided as a scientific tool to establish a more reasonable coastal water resource management plan.