• Title/Summary/Keyword: Natural Phenomena

Search Result 751, Processing Time 0.026 seconds

Review of Mixed-Effect Models (혼합효과모형의 리뷰)

  • Lee, Youngjo
    • The Korean Journal of Applied Statistics
    • /
    • v.28 no.2
    • /
    • pp.123-136
    • /
    • 2015
  • Science has developed with great achievements after Galileo's discovery of the law depicting a relationship between observable variables. However, many natural phenomena have been better explained by models including unobservable random effects. A mixed effect model was the first statistical model that included unobservable random effects. The importance of the mixed effect models is growing along with the advancement of computational technologies to infer complicated phenomena; subsequently mixed effect models have extended to various statistical models such as hierarchical generalized linear models. Hierarchical likelihood has been suggested to estimate unobservable random effects. Our special issue about mixed effect models shows how they can be used in statistical problems as well as discusses important needs for future developments. Frequentist and Bayesian approaches are also investigated.

Study of occurrence of cool air in summer and warm air in winter of Chonbuk Jinan Poonghyeol (전북 진안 풍혈의 여름철 냉풍 및 겨울철 온풍 발생 연구)

  • Kim, Young-Il;Shin, Young-Gy;Seo, Jeong-Ah;Choi, Yong-Don;Song, Tae-Ho;Kang, Chae-Dong;Kim, Seong-Sil;Rho, Jeong-Sun;Jeong, Si-Young;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
    • /
    • 2006.06a
    • /
    • pp.879-884
    • /
    • 2006
  • Jinan Poonghyeol in Chonbuk province Is famous for emitting cool air in summer and warm air in winter. Cause for these phenomena is studied by measuring temperature, humidity and air velocity of several locations around Jinan Poonghyeol Temperature variations under the ground are also measured. Analyzing data compiled from July 21, 2005 through May 26, 2006, it is presumed that storage effect of rocks and soil in this area and buoyance effect are the main causes for this mysterious natural air-conditioning phenomena.

  • PDF

Effect of particle size on direct shear deformation of soil

  • Gu, Renguo;Fang, Yingguang;Jiang, Quan;Li, Bo;Feng, Deluan
    • Geomechanics and Engineering
    • /
    • v.28 no.2
    • /
    • pp.135-143
    • /
    • 2022
  • Soils are natural granular materials whose mechanical properties differ according to the size and composition of the particles, so soils exhibit an obvious scale effect. Traditional soil mechanics is based on continuum mechanics, which can not reflect the impact of particle size on soil mechanics. On that basis, a matrix-reinforcing-particle cell model is established in which the reinforcing particles are larger-diameter sand particles and the matrix comprises smaller-diameter bentonite particles. Since these two types of particles deform differently under shear stress, a new shear-strength theory under direct shear that considers the stress concentration and bypass phenomena of the matrix is established. In order to verify the rationality of this theory, a series of direct shear tests with different reinforcing particle diameter and volume fraction ratio are carried out. Theoretical analysis and experimental results showed that the interaction among particles of differing size and composition is the basic reason for the size effect of soils. Furthermore, the stress concentration and bypass phenomena of the matrix enhance the shear strength of a soil, and the volume ratio of reinforcing particles has an obvious impact on the shear strength. In addition, the newly proposed shear-strength theory agrees well with experimental values.

A Study on Stratification Phenomena of Still Hydrogen-Methane Gas Mixture in a Vertical Urban Gas Pipe (도시가스 수직 배관 내 정지된 수소-메탄 혼합가스의 성층화 현상 연구)

  • Tae Kyun Kim;Jung Min Cho;Jaeyong Sung
    • Journal of the Korean Society of Visualization
    • /
    • v.22 no.1
    • /
    • pp.68-78
    • /
    • 2024
  • The stratification phenomena of still hydrogen (20%) and methane (80%) gas mixture in a vertical urban gas pipe have been investigated by simulating the flows based on a mixture model. The stratification is accompanied with the natural convection by the buoyancy force. The hydrogen volume fraction in the upper sections of the pipe increases with time but the increasing rate gets smaller due to the weaker buoyancy force. The pipe with a smaller diameter exhibits a higher peak of hydrogen concentration. The size of vortices is proportional to the pipe diameter. The slip velocity between hydrogen and methane oscillates with a large amplitude at the earlier stage of stratification and then the amplitude decreases sharply. The slip velocity decreases with the diameter, making the stratification become slower. The length of pipe does not affect the stratification since the pipe is sufficiently long relative to the size of vortices.

Chaos-Theoretical Approach to Media Convergence on Internet Media (인터넷미디어 중심의 매체융합 현상에 대한 카오스 이론적 접근)

  • Lee, Keun-Yong
    • Korean journal of communication and information
    • /
    • v.19
    • /
    • pp.185-211
    • /
    • 2002
  • Media convergence is prevalent all over the world, and is expected to change our lives dramatically in near future. Chaos theory is a new emerging theoretical approach to various social phenomena including organization management, economic system, stock market fluctuation, and so on. This thesis is intended to explain media convergence phenomena centered on internet media using basic concepts of chaos theory such as self-organization, co-evolution, and feedback loop. The implications of this tentative study are that we can apply chaos theory to media convergence as other social or natural phenomena, and that maintaining chaos state of media system is useful for accelerating creativities, and that developing media system as an organic system to cooperate with other relevant systems is helpful for promoting life qualities, and that establishing moral order or root value is desirable for implementing communicatopia.

  • PDF

A Research on the Conception Change Process of Secondary School Chemistry Major Teachers Related to the Evaporation Phenomena in the Air (대기 중의 증발 현상에 대한 중등학교 화학전공 교사들의 개념 변화 과정에 대한 연구)

  • Yang, Gee-Chang;Paik, Seoung-Hey
    • Journal of the Korean Chemical Society
    • /
    • v.52 no.1
    • /
    • pp.84-95
    • /
    • 2008
  • In this study, preconceptions held by chemistry major secondary school science teachers were searched in relation to explanations of water evaporation phenomena with phase equilibrium diagrams. 25 chemistry major science teachers were selected to complete questionnaires developed in this study and 6 among of them were selected to participate in follow-up interviews. Among these, 10 participants were selected for an evaluation of the change of their preconceptions through lessons developed in this study. From the results, it was found that many teachers believed that the phase equilibrium diagram could not explain water evaporation phenomena. They also thought that there was no relation between vapor pressure and the vertical axis of the phase equilibrium diagram. However, after the lessons in earth science, they recognized that the vapor pressure curve of the phase equilibrium diagram could be explained by adopting a saturated vapor curve. Because they had known the process of application the conceptions of saturated situation, nonsaturated situation, process of equilibrium movement in saturated vapor curve. They could understand natural phenomena such as evaporation with the phase equilibrium diagram through a change in their conceptions as guided from science lessons integrating earth science and chemistry.

Consideration of preservation methods for plant genetic resources in natural monument - Focusing on preparation for becoming effective of Nagoya Protocol - (천연기념물 식물유전자원의 보존방안 고찰 - 나고야의정서 발효 대비 중심으로 -)

  • Kim, Jung A;Kim, Hyo Jeong;Shin, Jin Ho;Kim, Dae Yeol;Jo, Woon Yeon
    • Korean Journal of Agricultural Science
    • /
    • v.41 no.3
    • /
    • pp.193-203
    • /
    • 2014
  • Natural Monument is a designated cultural property as part of the country. According to Article 2 of the Cultural Properties Protection Act, a national, ethnic and global heritage artificially or naturally formed, with a great historical, artistic, scientific and landscape significance is defined as a cultural heritage. Animals, plants, topography, geology, minerals, caves, biological products and special natural phenomena, having a great of historic, scenic and scientific value, are defined as the monument. According to Article 3 of Cultural Properties Protection Act, the conservation, management and utilization of National Heritage should be kept intact in its original form. So, Natural monuments are managing as retained its original form under the Basic Principles of current law. The highest population of coniferous tree in natural monument plant is ginkgo tree including 22 objects, followed by pines, junipers that order. And in case of broadleaf tree, there are zelkova trees, retusa fringe trees, pagoda trees, cork oaks, silver magnolias and etc. There are many of reported efficacy in available natural monument plants. The efficacy of plant species on pharmaceutical like anti-cancer, anti-diabetic, anti-obesity, antioxidant activity, neuroprotective, improves cholesterol, anti-inflammatory, liver protection and anti-bacterial efficacy, on cosmetics and beauty like the inhibiting formation of skin wrinkles, whitening effect, variety of materials and the efficacy of the proposed utilization of its various papers and etc have been widely reported. Before the Nagoya Protocol enters into force, the future role of the National Research Institute for Cultural Properties Administration of Cultural Heritage should be obtain a legal right to manage the social, cultural and national natural monument with emotional value to the plant genetic resource as a natural monument efficient ways to study and preserve traditional knowledge biological resources by securing a claim to the sovereignty of the material will be ready.

${\ll}$소문(素問).천원기대론(天元紀大論)${\gg}$에 대(對)한 연구(硏究)

  • Kim, Geun-Young;Yun, Chang-Yol
    • Journal of Korean Medical classics
    • /
    • v.11 no.1
    • /
    • pp.224-307
    • /
    • 1998
  • The above study is based upon the Theory of Five Woon(Reasons) and Six Qi(Climates), namely Five dynamic Yin and Yang, the principle of five-six combination, the rules of ten periodically changing Woon and twelve periodically changing Qi, and its reference to the main chapters of the theory by several experts. After careful, comprehensive research and study, the followings are concluded. 1. The Theory of Five Woon and Six Qi controls all of the physical phenomena of the universe, yet it originates from Essence of the Sky that is replete and in constant motion within the abysmal expanse of the universe. So it is natural to claim that it is the Essence of the universe that is the source of the variety of phenomena in nature. 2. There is order of dynamics in the Essence and it is Yin Yang Five Movement and expressed by Five Woon and Six Qi. Therefore the Five Woon and Six Qi, which is the climatic changes of nature, is the basis and condition for all of the natural, physical occurrences including the organic phenomena of human beings. 3. Since the Sky embodied the number Five, and the Earth the number Six, Qi of the Sky itself is consequently Five Woon and Qi of the Earth itself is Six Qi. 4. In Sixty Repetition Intervals (Yuk Sip Kap Ja), the Sky took the number Six, designating the six times repetition of the ten Intervals of the Sky and the Earth chose the number Five, symbolizing five times recurrence of the twelve Intervals of the Earth. Though the number for the Sky is Five and the number for the Earth is Six, the two combine and interact in order for the Sky to exploit the number Six and for the Earth to use the number Five. This interplay implies the relationship of operation and principle of Yin in Yang and Yang in Yin. 5. There seems to be clear and intimate association between five dynamics, five bearings and five Qi' in nature and five organs, five stamina, and five emotions in physiological activities of human beings. Such an correlation apparently demonstrates the idea of climatic changes of the universe in balance among human beings, the Sky, and the Earth. 6. Because nature is of an endlessly dynamic organism itself, to have changes must mear there being movements. Thus the climatic changes in nature are the subsequent consummation of the interaction in mutual balance and unbalance of the rise and fall of the Five Woon and Six Qi. 7. The interpretation, by Chang Ji Chong of "Yin and Yang of the Sky are for birth and growth and Yin and Yang of the Earth for demise and interment" as an explanation that the first half is mainly for life and the second half for death, appears to be correct by his view that there is balance and harmony between the long and short and the strong and weak. 8. In addition to Three Yang and Three Yin, as attributes of the Intervals of the Sky and the twelve Intervals of the Earth, Five Woon and Six Qi are utilized in the annual observation of the perpetual changes of climates.

  • PDF

A Effects of Natural Gas-Diesel/Hi-sene Dual Fuel Operation on Performance of a Heavy-Duty Diesel engine for Power Generation (발전용 대형 디젤 엔진의 천연가스-디젤/부생유(Hi-sene) 혼합연소 시 엔진 성능변화에 미치는 영향)

  • Cho, Jungkeun;Park, Sangjun;Song, Soonho
    • Journal of Energy Engineering
    • /
    • v.25 no.1
    • /
    • pp.122-130
    • /
    • 2016
  • This study is a numerical study using commercial simulation program GT-Power on 1.5MW diesel engine for power generation. Performance comparison has done for diesel operation with dual fuel operation for different engine load(50%, 75%, 100%) using the target engine model with additional gas injection system. Effect of using Hi-sene, which is actually being used in island area, instead of diesel was also studied. As a result, under 60% natural gas with diesel condition, BSFC was increased by 32% without modifying system. There was almost no change for natural gas/Hi-sene condition compared with natural gas/diesel condition. Decrease of burned fuel fraction was the main reason of these phenomena. After optimizing system, BSFC was improved by 2%.

A Study on the Traditional Dyeing of Korean buddhist Monk′s Robe (한국승복 염색에 대한 연구)

  • 차금주;정옥임
    • Journal of the Korean Society of Costume
    • /
    • v.50 no.5
    • /
    • pp.131-142
    • /
    • 2000
  • The philological consideration of Korean Buddhist Monk's robe and its reviving have been investigated in traditional way. The configuration and colour of Korean Buddhist monk's robes have been properly adapted for an period, territory, and atmospheric phenomena. In case of Korea, introduced Buddhism from China realize modern robe from under the influence of fusion of Chinese ornament culture and Korean traditional ornament culture. As a result of this modern robe has been consisted of a Buddhist monk's robe and a cope. The modem robes has been significantly affected by industrialization, contrary to ancient time taxed robes as public imposts. At present be familiar in mass production we have a preference for the easier way in making and even color forming. In this paper it is focused on dyeing part, which recognized its important in latest time, at first declined according to appearance of chemical dye, evaluated its convenience in use. That is, it is increased natural dye, people begin with recognition of difference of physical properties for dress dyed with chemical pigment and that with natural pigment. In consequence, I have presented that both making colour of gray using traditional method, and three demolished-color prescribed by Buddhist law. Of course, though it become generally know that dyeing of robes occupied significant part of traditional natural dyeing. But in case of religion, it also is important to know symbolical meaning involved in its colour. Most of Buddhism-believers or even Buddhists who actually be dress in robe are without knowing the meaning of colour, or its revealing method. There, I have considered mating three colour of demolished- color included blue, black, and red, and also represented dyeing method of Buddhist monk's robe using both charcoal and ink-spick. From religious font of view, as robes contains involving of blessing, I have an intention of improvement way in dyeing and succession and development of traditional culture through consideration of traditional dyeing method. And I have also intended to restoration the value of robe's colour, disappeared by the time. moreover, I have shown that dyeing with natural pigment is profitable for both environment and sanitary aspect.

  • PDF