• Title, Summary, Keyword: Gravity Potential Model

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Green Tourism Accessibility Evaluation for Policy Making of Rural Closed School - Case By Chungcheongnamdo Province - (농촌폐교 활용 정책수립을 위한 그린투어리즘 접근성 평가 - 충청남도를 대상으로-)

  • Chang, Woo-Seok;Jung, Nam-Su
    • Journal of Korean Society of Rural Planning
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    • v.19 no.4
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    • pp.293-306
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    • 2013
  • According to the increase of rural experience, that is important in satisfying needs of green tourism and vitalizing rural economy to use closed school in rural area as experience facility. For using closed school as experience facility, political and institutional assistants are needed in effective equipments and stable operation based on multi-perspective approach and analysis. In this study, we try to evaluate green-tourism accessibility of rural experience facility remodeled from closed school considering regional population and spatial characteristics. In evaluating process, gravity potential model are adapted with considering group size of customer and distance-friction coefficient. Distance-friction coefficient is a function of user restriction which depend on possible activity in each experience facility. Green tourism accessibility of experience facility is calculated with summation of accessibility to each region, and we analyzed it as a group by closed school type and location with application in Chungcheongnam-do. We found a correlation between green tourism accessibility of rural closed school and their income.

Classification of Hyperspectral Images based on Gravity type Model (중력모델에 기반한 하이퍼스텍트럴 영상 분류)

  • Byun, Young-Gi;Lee, Jeong-Ho;Kim, Yong-Min;Kim, Yong-Il
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • pp.183-186
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    • 2007
  • Hyperspectral remote sensing data contain plenty of information about objects, which makes object classification more precise. Over the past several years, different algorithms for the classification of hyperspectral remote sensing images have been developed. In this study, we proposed method based on absorption band extraction and Gravity type model to solve hyperspectral image classification problem. In contrast to conventional methods that are based on correlation techniques, this method is simple and more effective. The proposed approach was tested to evaluate its effectiveness. The evaluation was done by comparing the results of preexiting SFF(Spectral Feature Fitting) classification method. The evaluation results showed the proposed approach has a good potential in the classification of hyperspectral images.

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Biomimetic Balancing Mechanism for Walking Robot (생체모사를 통한 보행로봇의 균형감에 관한 연구)

  • Kim, Jong Jin;Chung, Seong Youb
    • Journal of Institute of Convergence Technology
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    • v.4 no.2
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    • pp.55-59
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    • 2014
  • A cat is able to quickly recover balance from unstable posture. To observe the balance recovery procedure of the cat, an impulse is applied to the cat while walking on a narrow bridge. We find that it rotates its tail toward the falling direction. In our previous research, the balance recovery procedure is analyzed based on the law of the angular momentum conservation and then a key equation is derived to maintain the balance. However, it did not consider the gravity, so the performance is not good. In this paper, a new dynamic model is proposed using the Lagrangian mechanics. In the method, the gravity is included in the potential energy. Through the proposed dynamic model, controlling the balance of a walking robot is possible.

Effect of biaxial stress state on seismic fragility of concrete gravity dams

  • Sen, Ufuk;Okeil, Ayman M.
    • Earthquakes and Structures
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    • v.18 no.3
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    • pp.285-296
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    • 2020
  • Dams are important structures for management of water supply for irrigation or drinking, flood control, and electricity generation. In seismic regions, the structural safety of concrete gravity dams is important due to the high potential of life and economic loss if they fail. Therefore, the seismic analysis of existing dams in seismically active regions is crucial for predicting responses of dams to ground motions. In this paper, earthquake response of concrete gravity dams is investigated using the finite element (FE) method. The FE model accounts for dam-water-foundation rock interaction by considering compressible water, flexible foundation effects, and absorptive reservoir bottom materials. Several uncertainties regarding structural attributes of the dam and external actions are considered to obtain the fragility curves of the dam-water-foundation rock system. The structural uncertainties are sampled using the Latin Hypercube Sampling method. The Pine Flat Dam in the Central Valley of Fresno County, California, is selected to demonstrate the methodology for several limit states. The fragility curves for base sliding, and excessive deformation limit states are obtained by performing non-linear time history analyses. Tensile cracking including the complex state of stress that occurs in dams was also considered. Normal, Log-Normal and Weibull distribution types are considered as possible fits for fragility curves. It was found that the effect of the minimum principal stress on tensile strength is insignificant. It is also found that the probability of failure of tensile cracking is higher than that for base sliding of the dam. Furthermore, the loss of reservoir control is unlikely for a moderate earthquake.

Design of steel moment frames considering progressive collapse

  • Kim, Jinkoo;Park, Junhee
    • Steel and Composite Structures
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    • v.8 no.1
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    • pp.85-98
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    • 2008
  • In this study the progressive collapse potential of three- and nine-story special steel moment frames designed in accordance with current design code was evaluated by nonlinear static and dynamic analyses. It was observed that the model structures had high potential for progressive collapse when a first story column was suddenly removed. Then the size of beams required to satisfy the failure criteria for progressive collapse was obtained by the virtual work method; i.e., using the equilibrium of the external work done by gravity load due to loss of a column and the internal work done by plastic rotation of beams. According to the nonlinear dynamic analysis results, the model structures designed only for normal load turned out to have strong potential for progressive collapse whereas the structures designed by plastic design concept for progressive collapse satisfied the failure criterion recommended by the GSA guideline.

DENSITY STRUCTURE AND STABILITY OF THE SUBCOMPONENTS IN GIANT MOLECULAR CLOUD COMPLEXES

  • Yoo, Chin-Woo;Hong, Seung-Soo
    • Journal of The Korean Astronomical Society
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    • v.19 no.1
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    • pp.33-49
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    • 1986
  • Radial distribution of internal density has been determined for thirteen subclouds in the three giant molecular cloud complexes accompanying Mon OB1, Mon OB2 and CMa OB1 associations, We modeled their radial density structures with the density distribution of isothermal gas spheres. Most of the subclouds, nine out of the thirteen, are well described by isothermal spheres of single component; while the rest four require an additional component. Total mass and potential energy of each subcloud are also derived from the radial density structure; thermal energy and internal velocity dispersion required for sustaining the density structure are deduced from the isothermal gas model. Our derived masses of the clouds are comparable to the values determined by Blitz (1978) under LTE assumption. This agreement suggests that the correction factor for non-LTE effect on mass-estimate is not far from unity. The ratio of the gravitational potential energy to the kinetic energy of thermal motion is as large as 250; hence the thermal motion alone cannot support these clouds against the gravity. Being supported by turbulence motion with velocities of six to seven times the thermal velocity, the clouds of one-component type seem to be in equilibrium with the gravity; while the clouds of two-component type are likely to be in the stage of gravitational collapse.

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A study on the crustal structure of the continental margin in the East Sea along the Korea Peninsula using potential data (포텐셜자료를 이용한 한반도 동해 대륙주변부의 지각구조에 관한 연구)

  • Kim, Chang-Hwan;Yoo, Lee-Sun;Park, Chan-Hong;Suk, Dong-Woo
    • Journal of the Korean Geophysical Society
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    • v.10 no.1
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    • pp.13-25
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    • 2007
  • We investigated the undulation of Moho depth and the crustal structure of the continental margin in the East Sea along the Korea Peninsula from inversion and modelling using potential data and previous seismic results. Free-air gravity anomalies generally reflect topography effect. Bouguer gravity anomalies increase toward the Ulleung Basin, indicating that Moho depth is shallower under the Ulleung Basin. Positive magnetic anomalies exist along the continental margin and decrease toward the Ulleung Basin. In analytic signal, the small anomaly in the Hupo Bank infers that the Hupo Bank is uplifted by igneous intrusion and the strong anomaly on the continental slope denotes existence of SDR(seaward dipping reflectors), which are in accordance with the location of SDR detected in previous seismic studies. The inversion result of Bouguer gravity anomaly and the 2-dimensional gravity modelling indicate that the undulation of Moho depth shallows from the continental shelf toward the Ulleung Basin. This is in good agreement with the Moho depth calculated by the previous seismic velocity model using ocean bottom seismometer(OBS). The 2-dimensional gravity modelling infers magmatic underplating zone under the lower continental crust on the continental margin of the East Sea, indicating the possible rifiting of the continental margin.

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A Study on the Export Potential of Bangladesh's Ready-Made Garments (중력모형을 이용한 방글라데시 의류 유망 수출시장 추정)

  • Hossain, Sumon;Oh, Keunyeob
    • Management & Information Systems Review
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    • v.37 no.2
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    • pp.87-108
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    • 2018
  • This article explores the international trade flow of Bangladesh's ready-made garments (RMG). We first suggest the brief history and an international structure of trade among countries by using the trade volume. Then we implemented a gravity model regression with the sample of 38 major partner countries in order to investigate the potential export market for the RMG industry. The fixed effect and random effect model for the panel data during the period of 1990 to 2011 are estimated. Our result shows that Bangladesh's RMG exports are affected positively by the size of economy, inflation, exchange rate, foreign direct investment(FDI) and trade openness. On the other hand, the distance between trading partners are related negatively with the trade volume. We used the estimated coefficients from the panel regression in order to predict RMG export potential of Bangladesh. This might show which country is the promising export market for Bangladesh RMG industry. We found that Bangladesh has the highest potential of RMG export with Japan and USA, which seem to have considerable room for export growth if trade barriers and constraints are removed. We added some policy implications for encouraging the RMG export of Bangladesh by using the results from the analysis.

Green strategy to produce large core-shell affinity beads for gravity-driven API purification processes

  • Viveiros, Raquel;Dias, Francisco M.;Maia, Luisa B.;Heggie, William;Casimiro, Teresa
    • Journal of Industrial and Engineering Chemistry
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    • v.54
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    • pp.341-349
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    • 2017
  • In this work, Molecular Imprinted Polymers (MIPs)-layered silica beads which have affinity for a model pharmaceutical impurity, acetamide (ACET) were developed using supercritical carbon dioxide ($scCO_2$) technology. Silica beads were first functionalized using two different green strategies, grafting to (MPS/EtOH in $scCO_2$) and grafting from (plasma technology). These core beads were then used as seed particles in the synthesis, in $scCO_2$ of a MIP layer. Dynamic binding tests were performed in order to evaluate the affinity of the resulting silica core - MIP shell beads to ACET and the efficiency of its removal from an active pharmaceutical ingredient - Beclomomethasone dipropionate (API) crude mixture. ACET was preferentially retained over analogue molecules, benzamide (BENZ) and pivalamide (PIV). The core-shell MIP beads were packed in a SPE column (396.5 mg in a 3 mL SPE tube) and evaluated as a potential gravity-driven purification device, enabling the removal of 100% of ACET whilst losing only 0.37% of API from a model mixture solution-10 mL of ACET and API ($0.25mg\;mL^{-1}+3.5mg\;mL^{-1}$).

An Analysis of Broadband Accessibility at the County Level in the United Slates: a Spatial Analytical Approach Using GIS (미국 카운티의 초고속 인터넷 서비스에 대한 접근성 분석: GIS를 이용한 공간 분석적 접근)

  • Lee, Gun-Hak
    • Journal of the Korean Geographical Society
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    • v.43 no.2
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    • pp.202-219
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    • 2008
  • As demand for high speed Internet service has explosively increased in the United States for the past decade, the construction or upgrades of telecommunication infrastructure has also been rapidly followed. Though currently many people in urbanized areas can be provided advanced broadband services, there are still challengeable areas to be served, such as remote or low populated areas because those areas are potentially non-profitable to commercial broadband service providers. This paper addresses the spatial disparity or in a broader term, the 'digital divide' of the broadband access by the county level in the United States. We propose the quantified measure of the county level broadband accessibility for identifying such digital divide. The developed measure is a hybrid form of the classical gravity based potential model and network topological accessibility, encouraged from the lack of prior efforts eying to explicitly incorporate the understanding of the whole process of the Internet access. The computational tasks are performed in a GIS platform, which includes several programmed functions.