• Title/Summary/Keyword: Natural change

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A Logical Simulation of Dynamic Natural Phenomena Based on Event Propagation Graph (사건 전파그래프에 기반한 동적인 자연현상의 논리적 시뮬레이션)

  • Park, Jung-Yong;Park, Jong-Hee
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.38 no.4
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    • pp.10-21
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    • 2001
  • This paper develops a logical simulation method for by dyversity of situations. Most existing systems, for example, games and infant tutoring systems lead users to virtual environment with unfolding situations, but are not designed to induce the change of the environment itself. In this paper, a logically simulated environment is created by defining situations and single events based on situation hierarchy structure. We elaborate the occurrence of events by classifying the causality. The occurrence or natural phenomena is dictated by physical laws and natural phenomena are expressed as the transition of the event based on event association. Specifically we define the source of the event for natural phenomena and we consider the existence of objects as a primary factor in event occurrence. The advantages of this approach include the reuse of events, that is, different events can be generated in the same flow with fresh conditions. This allows us to implement a more practical and logical environment. A drawback to this method is the difficulty in dividing a situation into events. The proposed method was implemented in the context of the change of season among natural phenomena.

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A Case Study on the Reduction of Noise and Vibration at the Backpass Heat Surface in the Power Plant Boiler (발전용 보일러 후부 전열면 소음진동 저감에 관한 연구)

  • Lee, Gyong-Soon;Lee, Tae-Gu;Moon, Seung-Jae;Lee, Jae-Heon
    • Plant Journal
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    • v.4 no.3
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    • pp.54-59
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    • 2008
  • The resonance of boiler is caused by exciting force in the gas path and it generates the vibration by the harmony of boiler's dimensional factor. According to trending toward the boiler of increasing capacity and a bigger size, it has a problem of the vibration at back-pass heating surfaces. We can predict such vibrations as comparison between vortex frequency and gas column's natural frequency. We can't rely on the method for the past decades because of changing parameters, such as an allowable error, gas temperature, gas velocity, Strouhal number. We can reduce the vibration to use the seasoning effect and change the operating condition in coal fired boiler but it's not essential solution. When the vibration occurred in the model boiler, we must measures the acoustic pressure and frequency of places for considering the means. So far, we confirmed the problem from field measures and theoretical analysis about the acoustic vibration of boiler. We installed anti-acoustic baffle in a existing boiler to change the acoustic natural frequency at the cavity, which results in reducing the acoustic vibration. The first, we prove that the acoustic resonance is caused by harmonizing vortex shedding frequency of tube heat surface with acoustic natural frequency of cavity in the range of 650~750 MW loads. The second, the acoustic resonance at the back-pass heating surface has the third order of acoustic natural frequency at the second economizer. We install five anti-acoustic baffles at the second economizer to reducing the resonance. We confirm considerably reducing the acoustic vibration of boiler during the commercial boiler.

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Natural Dyeing Using Tea Extract II - The Effect of Dyeing Condition on Dyeing Characteristics of Coffee Extract Dyed Silk Farbic-

  • Yoo, Hyun-Geun;Kim, Sin-Hee
    • Journal of Fashion Business
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    • v.10 no.3
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    • pp.78-86
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    • 2006
  • Coffee extract dyeing on silk fabric using various mordanting agents at different mordanting condition was studied in our previous research. Coffee extract dyeing can exert beautiful colors and have several advantages over the conventional natural dyeing. Since most of natural dyes are expensive for mass production, strongly season and source dependent, and hard to store, and therefore, coffee waste was used as natural dye to create beautiful colors in this study. Coffee waste is inexpensive and easy to store, and provide a comparatively regular quality regardless of season and source. The effects of dyeing condition such as dyeing temperature, dyeing time, and liquor ratio on dyeing characteristics of silk fabrics were investigated. Coffee extract dyed silk showed brilliant colors, and the colors were different with the kind of mordant. Cu, Sn, and Al mordanted silks showed golden yellow with subtle change of hue and value, while Fe mordanted silk showed a brownish green color upon coffee extract dyeing. As the dyeing temperature increased, the dyeability generally increased in all mordanted silk fabrics except Fe mordanted silk until $45^{\circ}C$. The dyeing temperature did not affect the dyeability of Fe mordanted silk fabric. As the liquor ratio increased, the dyeability showed a gradual increase in all mordanted silk except Cu mordanted silk. Cu mordanted silk fabric showed an abrupt increase in dyeability at liquor ratio1:150. The dyeing time effect can be separated into 2 stages. During the initial half an hour, the dyeability did not change significantly, and then, increased after 45 min. dyeing time duration. A further increase in dyeing time after 45 min. did not affect the dyeing efficiency in all mordanted silk fabrics except the Cu mordanted.

Structure, Alpha and Beta Diversity of Natural Forest Areas in Eco-Zones of Taraba State, Nigeria

  • Dau Henry, Japheth;Bunde Bernard, Meer
    • Journal of Forest and Environmental Science
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    • v.39 no.1
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    • pp.1-12
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    • 2023
  • To understand the health conditions and growth patterns of forest estate for environmental resilience and climate change mitigation, assessment of structure and species diversity is paramount. This study aimed at assessing the structure, alpha, and beta diversities of tree species in three ecological zones in Taraba, Nigeria for management purposes. In recent time, no research has been reported on the structure and beta diversity of the study areas. A systematic sampling design was used for data collection. Five sample plots of 50×50 m were laid in each of the six natural forest areas. The result showed a mean DBH (42.5 cm) and a tree height (15.0 m) from the forests. The forests have a structure of an inverse "J-shape," which is typical of natural forests in the tropics. The southern Guinea savanna zone had the highest mean Shannon-Weiner diversity index (2.8). The least beta diversity index (0.02) was between Baissa and Jen Gininya forest areas. Baissa and Bakin Dutse Protected Forest Areas (PFAs) contained 76.5% of the tree species. There is a high chance of all tree species to be found in these 2 forest areas. Proximity to a location influences how similar two tree species are, according to the least beta diversity index (0.02) recorded. The Federal Government's method of management for the forest, known as Gashaka Gumti National Park, may be responsible for the high beta diversity index in the Montane ecozone. Therefore, it should be strongly encouraged to practice strict oversight of natural areas, as their contributions to reducing climate change in Taraba State, Nigeria, cannot be overstated.

Proposal of a prospective public convenience through vertical division of space;TOILET TOWER (공간의 수직분할을 통한 미래형 공중화장실 제안;타워식 화장실)

  • Son, Bo-Ra
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2006.11a
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    • pp.212-215
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    • 2006
  • The Beautiful rest room is simple how to think. We need to understand that excretion is important as much as eating. When we didn't have foods, eating was important in itself no matter what our lives environments. But now we want to eat in more dignified and more cultural place. Most of restaurants spend money on adjusting place for the consumes' desire. It is same way about rest room, it is time to change our rest room to place of rest and speculation over the place which we fix our natural urge. We can fix our natural urge, take a rest, and get creative ideas in more convenient, more healthy and more comfortable. It is time for us to change out thought about rest room; it is not dirty and stink place, but civilized living place like developed country. Also, we need new concept to take a triangular position about rest room is one of structure over just decorations. This research suggest new public rest room without precedent based on instance analysis about rest room inside and outside the country.

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Acoustic Enhancement of Solid-Liquid Phase Change Heat Transfer (음향 흐름에 의한 고-액 상변화 열 전달의 촉진)

  • 박설현;오율권
    • Journal of Energy Engineering
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    • v.11 no.3
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    • pp.262-268
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    • 2002
  • The present paper investigated the effect of ultrasonic vibrations on the melting process of phase-change materials (PCM). Furthermore, the present study considered constant heat-flux boundary condition, whereas many of the previous researches had adopted constant wall-temperature condition. The results of the present study revealed that ultrasonic vibrations accompanied the effects like acoustic streaming, cavitation, and thermally-oscillating flow. Such effects are a prime mechanism in the overall melting process when ultrasonic vibrations are applied. They speed up the melting process as much as 2.5 times, compared with the result of natural melting. Also, energy can be saved by applying ultrasonic vibrations to the natural melting. In addition, temperature and Nusselt numbers over time provided a conclusive evidence of the important role of ultrasonic vibrations on the melting phenomena.

Reduction of Energy and Food Security in DPRK due to Deforestation

  • SHIN, Eunsoo Justin;Ahn, Ji Whan
    • Journal of Energy Engineering
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    • v.27 no.3
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    • pp.63-67
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    • 2018
  • The Democratic People's Republic of Korea, or the DPRK, is one of the poorest country in world facing chronic economic, energy and food security issues. Prolonged improper management of economic and natural resources has led to extreme poverty, malnutrition and critically vulnerability to nature's forces. Presistent deforestation and forest degradation in the DPRK has national and global consequences which has attracted attention from international community, whose offering financial and technical assistance for targeted interventions. Through REDD+ programs, the DPRK has the opportunity to establish its credentials as a responsible nation while improving the quality of life of its population. This study offers an enabling context under which suitable climate change action related to forestry can be identified and implemented in the DPRK.

A Study on the Critical Elements in the Commentaries on Competition of the Hospital Architecture in Germany (독일 병원건축 설계경기의 심사평에 나타난 평가항목에 관한 연구)

  • Cho, Ja Yeon
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.9 no.1
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    • pp.53-60
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    • 2003
  • In this study, I investigate the critical evaluation elements at the architectural competition held nationwide in Germany. These evaluation elements, which can be regarded as the important design evaluation criteria, are selected by the design competition committee. Generally, in Germany the design competition committee consist of professors and famous architects who have theoretical and practical abilities with their own office. I classify and analyze the critical evaluation elements of seventy committee members, working on the selected nine prize-winners in Germany from 1997 to 2001. I conclude that the critical evaluation elements, ordered by frequency are : (1)circulation, (2)context, (3)function, (4)landscape & outside space, (5)organization of space, (6)arrangement of building, (7)form, arrangement of building, (7)form, (7)growth & change, (9)elevation design, (10)utilization of natural light. These design evaluation growth & change, (9)elevation design, (10)utilization of natural light. These design evaluation criteria for Hospital Architecture in Germany also can be applied to the evaluation methods of the korean Healthcare facility design.

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A Study on the Vibration Behavior of the Fuel rods Continuously Supported by a Rotatory and Bent Spring System (회전 및 굽힘 스프링 기구로 연속 지지된 핵연료봉의 진동연구)

  • 강흥석;송기남;윤경호;정연호;임정식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.454-460
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    • 1998
  • The vibration behavior of fuel rods has been analyzed by FEM in consideration of axial force and support spring constants. The axial compression force on the fuel rod in reactor decreases with the fuel rod burnup, and its decrease makes the natural frequencies of fuel rod considerably increase. The change of support spring constant can contribute to the remarkable change of the mode shapes, but not greatly to the natural frequencies. The reaction forces of support springs are obtained from normalizing the lst mode with the max. 0.2 mm displacement. The calculated reaction forces are larger than the previous results obtained by disregarding the deflections of the support springs.

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Model-Based Damage Detection Methods for Structural Health Monitoring of PSC Bridges (PSC교량의 구조건전성 모니터링을 위한 모델기반 손상검색기법)

  • 박재형;이병준;김정태
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.550-557
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    • 2004
  • In this paper, structural damage in PSC bridges is monitored by using model-based damage detection methods. First numerical experiments on the test structure are described. Dynamic responses of the test structures are obtained fur several damage scenarios. The change in natural frequency and the change in nude shape curvature are selected as features to represent the states of the structure. Next a damage localization algorithm from monitoring the changes in natural frequency is outlined. Also, the damage localization algorithm from monitoring the changes in nude shapes is outlined. Finally, the damage localization algorithms are used to predict damage in the test structure. The results of the analysis indicate that the model-based damage detection methods correctly predicted damage in the test structure.

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