• Economic and Environmental Geology
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• v.24 no.4
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• pp.409-419
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• 1991

A gravity survey was conducted in the western Marquette district, Michigan, to delineate the subsurface structure and the relationship of the Proterozoic Marquette Range Supergroup rocks (Precambrian X) and Archean basement (Precambrian W) where the Republic, Michigan River, and Marquette troughs join. In order to accomplish these purposes, three hundred and forty gravity stations were established in the area of $380km^2$. Positive anomalies are associated with the Precambria X, metasedimentary sequence which has a higer density with respect to the Precambrian W, basement rocks. The dominant positive gravity anomalies follow the axes of the three troughs which are filled with Precambrian X rocks. Subsurface structure was modelled by using the Talwani method. Gravity model studies indicate that the Marquette trough is asymetrically shaped and steeply dipping at the north edge except in the eastern part of the study area. The interpretive results obtained from two dimensional model studies suggest that the basement structure of the study area is relatively flat, and that the troughs were formed contemporaneously.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.758-765
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• 2015

This paper proposes an attitude control system to keep the balance for a two-wheeled mobile manipulator which consists of a mobile platform and a three D.O.F. manipulator. In the conventional control scheme, complicated dynamics of the manipulator need to be derived for balancing control of a mobile manipulator. The method proposed in this paper, however, three links are considered as one body of mass and the dynamics are derived easily by using an inverted pendulum model. One of the best advantage of a sliding mode controller is low sensitivity to plant parameter variations and disturbances, which eliminates the necessity of exact modeling to control the system. Therefore the sliding mode control algorithm has been adopted in this research for the attitude control of mobile platform along the pitch axis. The center of gravity for the whole mobile manipulator is changing depending on the motion of the manipulator. And the orientation variation of center of gravity is used as reference input for the sliding mode controller of the pitch axis to maintain the center of gravity in the middle of robot to keep the balance for the robot. To confirm the performance of controller, MATLAB Simulink has been used and the resulting algorithms are applied to a real robot to demonstrate the superiority of the proposed attitude control.

• Environmental Engineering Research
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• v.11 no.5
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• pp.241-249
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• 2006

A mathematical model is described for the prediction of convective upward transport of an organic solvent driven by evaporation at the surface, which is known as the major transport mechanism in the in-situ photolysis of a soil contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD). A finite-element model was proposed to incorporate the effects of multiphase flow on the distribution of each fluid, gravity as a driving force, and the use of hysteretic models for more accurate description of k-S-p relations. Extensive numerical calculations were performed to study fluid flow through three types of soils under different water table conditions. Predictions of relative permeability-saturation-pressure (k-S-p) relations and fluids distribution for an illustrative soil indicate that hysteresis effects may be quite substantial. This result emphasizes the need to use hysteretic models in performing flow simulations including reversals of flow paths. Results of additional calculations accounting for hysteresis on the one-dimensional unsaturated soil columns show that gravity affects significantly on the flow of each fluid during gravity drainage, solvent injection, and evaporation, especially for highly permeable soils. The rate and duration of solvent injection also have a profound influence on the fluid saturation profile and the amount of evaporated solvent. Key factors influencing water drainage and solvent evaporation in soils also include hydraulic conductivity and water table configuration.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.172-183
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• 2009

For the effects of the nonlinear temperature profiles and reduced-gravity conditions we conduct a two-dimensional numerical modeling and simulations on the physical vapor transport processes of $Hg_2Cl_2-Xe$ system in the horizontal orientation position. Our results reveal that: (1) A decrease in aspect ratio from 5 to 2 leads to an increasingly nonuniform interfacial distribution and enhances the growth rate by one-order magnitude for normal gravity and linear wall temperature conditions. (2) Increasing the molecular weight of component B, Xenon results in a reduction in the effect of solutal convection. (3) The effect of aspect ratio affects the interfacial growth rates significantly under normal gravity condition rather than under reduced gravitational environments. (4) The transition from the convection-dominated regime to the diffusion-dominated regime ranges arises near at 0.1g$_0$ for operation conditions under consideration in this study.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.69-74
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• 2012

In this research equations of motion of a Wheeled Inverted Pendulum (WIP) which is running on the inclined road and changing its center of gravity. Difference between a conventional cart inverted pendulum and the WIP is also considered. The WIP has small planar size so that it has been used as a mobile platform for several applications which require slender frame in order to travel on the narrow road. The WIP has almost the same unstable properties as conventional inverted pendulums have. There needs an aggressive control scheme for the WIP not to fall down. In order to design a high performance control scheme, equations of motion of the WIP, which is running under various environment and operating conditions, should be derived and considering its properties is necessary.

• Journal of the Korean earth science society
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• v.23 no.1
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• pp.15-29
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• 2002

Bayesian inversion for gravity and resistivity data was performed to investigate the cavity structure appearing as a lava tunnel in Cheju Island, Korea. Dipole-dipole DC resistivity data were proposed for a prior information of gravity data and we applied the geostatistical techniques such as kriging and simulation algorithms to provide a prior model information and covariance matrix in data domain. The inverted resistivity section gave the indicator variogram modeling for each threshold and it provided spatial uncertainty to give a prior PDF by sequential indicator simulations. We also presented a more objective way to make data covariance matrix that reflects the state of the achieved field data by geostatistical technique, cross-validation. Then Gaussian approximation was adopted for the inference of characteristics of the marginal distributions of model parameters and Broyden update for simple calculation of sensitivity matrix and SVD was applied. Generally cavity investigation by geophysical exploration is difficult and success is hard to be achieved. However, this exotic multiple interpretations showed remarkable improvement and stability for interpretation when compared to data-fit alone results, and suggested the possibility of diverse application for Bayesian inversion in geophysical inverse problem.

• Journal of the Korean earth science society
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• v.45 no.5
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• pp.456-468
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• 2024

River discharge is a crucial indicator of climate change and requires accurate and continuous estimation for effective water resource management and environmental monitoring. This study used satellite gravimetry data to estimate river discharge in major basins with high discharge volumes, specifically the Congo and Orinoco basins. By enhancing the spatial resolution of gravity data through advanced post-processing techniques, including forward modeling and river routing schemes, we effectively detected changes in the water mass stored within river channels. Additionally, signals from surrounding regions were statistically removed using the Empirical Orthogonal Function (EOF) analysis to isolate river-specific discharge signals. These refined signals were then converted into river discharge data through seasonal calibration using the modeled discharge data. Our results demonstrate that this method yields accurate and reliable discharge estimates comparable to in-situ measurements from gauge stations, even without ground-based surveys such as an Acoustic Doppler Current Profiler (ADCP) field campaigns. This research highlights the significant potential of satellite-based gravity data as an alternative to traditional ground surveys, providing practical information on the hydrological status of regions associated with large-scale river systems.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1057-1062
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• 2007

The purpose of this study is to find out design parameters of vibrating screen, such as particles motion, specific gravity, shape, and kinetic friction. In order to approach this problem, four materials of construction wastes, wood, styrofoam, concrete, and sand are used for dynamic modeling. To present friction between the particles material and tilt plates material, these particles model is applied in order to verify effectively. Generally, the vibrating screen is composed of three assemblies such as screen, wastes guide, supported of screen. This model regards vibrator as system of screen fixed tilt plates. The model is analyzed to present what kind of particles motion while the system is vibrating. and this vibration system has been implemented in a ADAMS dynamaic program. This modeling is consist of dynamic model separation state on particle size. This study make good technique to verify in theory.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.120.3-120
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• 2002

1. Introduction $\textbullet$ Immune system is an evolutionary biological system to protect innumerable foreign materials such as virus, germ cell, and etc. Immune algorithm is the modeling of this system's response that has adaptation and reliableness when disturbance occur. $\textbullet$ In this paper, Immune algorithm is applied to the Steering Controller of AGV in container yard. $\textbullet$ And then the computer simulation result from the viewpoint of yaw rate and lateral displacement is analyzed and compared with result of conventional PID controller. 2. Dynamic Modeling of AGV $\textbullet$ Dynamic modeling has high degree of freedom. But, basic assumptions of this model are that the center of gravity(CG)...

• Journal of the Korea Computer Graphics Society
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• v.10 no.2
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• pp.10-16
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• 2004

This paper presents an interactive technique that produces static human hairstyles by generating individual hair strands of the desired shape and color, subject to the presence of gravity and collisions. A variety of human hairstyles can be generated by supplying a few parameters to the modeling core, which consists of the wisp generator and hair deformation solver. Wisps are generated employing statistical approaches. As for hair deformation, a method that is not physically-based is proposed to efficiently account for the effects of gravity and collisions. The technique produces various hairstyles much faster than previously proposed methods, and the styles generated by this technique are remarkably realistic.