• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.258-264
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• 1999

In this study, a computer program was developed for analysis of the orthotropic curved ring sector plates. In the developing program , the thin-plate theory and multi-base coordinate system was adopted. The effect of design factors-boundary conditions, loading conditions, steel ratio, open angle, radius of curvature and relative flexural rigidity between slab and edge-beam-on the behavior of the circular ring sector plates were discussed. Also, the practical limitations was proposed to replace the problem of the orthotropic sector plate by equivalent rectangular plage.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.125-128
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• 2000

In this paper, the handoff margins are analyzed using the propagation attenuation which is modeled as a product of the fourth power of the distant and a log-normal random variable whose standard deviation is 8 ㏈. The effect of handoff techniques on cell coverage for CDMA system are shown that soft handoff increases cell coverage relative to hard handoff. When the cell radius extends 5-10 % and the outage probability is 10 %, the relative cell coverage area is extended 3.22 ㏈-3.99 ㏈ and 2.55 ㏈-2.85 ㏈ with power control and without power control, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.42-45
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• 2002

General wheel mark in mono-crystalline silicon wafer finding is able to be expected because it depends on radius ratio and angular velocity ratio of wafer and wheel. The pattern is predominantly determined by the contour of abrasive grits resulting from a relative motion. Although such a wheel mark is made uniform pattern if the process parameters are fixed, sub-surface defect is expected to be distributed non-uniformly because of characteristic of mono-crystalline silicon wafer that has diamond cubic crystal. Consequently it is considered that this phenomenon affects the following process. This paper focused on kinematic analysis of wafer grinding process and simulation program was developed to verify the effect of process variables on wheel mark. And finally, we were able to predict sub-surface defect distribution that considered characteristic of mono-crystalline silicon wafer

• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.85-88
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• 2005

Experimental study has been conducted to evaluate characteristics of particle laden flows at the ratio of channel diameter to particle diameter (B = 14.9, 21.6 and 55). Particle velocities and radial concentrations are obtained using a microscope Nd:YAG laser and cooled CCD camera. Results show that there are relative velocities between the fluid and the particles at B = 14.9. It is also observed that the particles are accumulated at r=$0.5\∼0.82R$, with R being tile tube radius, and particle migration occurs at small Reynolds number, by comparing with the results obtained in macro scale. This gives optimal factors for designing microfluidic channels for cell or Particle separation, particle focusing, and so on.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2537-2539
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• 1999

In order to widen the radius of electric vehicle (EV) travel recharging points must be provided in sufficient numbers and at convenient places. The cost of providing side an infrastructure is at preset, not well documented and this lack of information acts as a detersent to prospective insestors in EV technology. This paper acts as a preliminancy investigation into the cost of infrastructure is the different situation i.e for the private owner, the fleet owner or for the public. It provides an overview of the items required and this relative costs. Cost will however, vary from country to country and application to application, and this paper two acts purely as guide to the type of equipment and its relative costs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.12
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• pp.1747-1755
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• 2002

A complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in semi-infinite solid materials. The influence of the parameters, such as radius and modulation frequency of the heating beam and the thermal diffusivity, was studied. Usually, thermal diffusivity was determined by the deformation angle and phase angle as the relative position between the heating and probe beams. In this study, we proposed the simple analysis method based on the real part of deformation gradient as the relative position between two beams. It is independent in the parameters such as power of heating beam, absorption coefficient, reflectivity, Poisson's ratio, and thermal expansion coefficient.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.178-182
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• 2007

In this study, we evaluated current raingauge network of Soyanggang dam region applying spatial-correlation analysis and Entropy theory to recommend an optimized raingauge network. In the process of analysis, correlation distance of raingauge stations is estimated and evaluated via spatial-correlation method and entropy method. From this correlation distances, respective influencing radii of each dataset and each methods is assessed. The result of correlation and entropy analysis has estimated correlation distance of 25.546km and influence radius of 7.206km, deducing a decrease of network density from $224.53km^2$ to $122.47km^2$ which satisfy the recommended minimum densities of $250km^2$ in mountainous regions(WMO, 1994) and an increase of basin coverage from 59.3% to 86.8%. As for the elevation analysis the relative evaluation ratio increased from 0.59(current) to 0.92(optimized) resulting an obvious improvement.

• Advances in biomechanics and applications
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• v.1 no.3
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• pp.169-185
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• 2014

Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.377-388
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• 2020

In this paper, the autonomous mobile robot whit only LRF sensors proposes an algorithm for avoiding moving obstacles in an environment where a global map containing fixed obstacles. First of all, in oder to avoid moving obstacles, moving obstacles are extracted using LRF distance sensor data and a global map. An ellipse-shaped safety radius is created using the sum of relative vector components between the extracted moving obstacles and of the autonomuos mobile robot. Considering the created safety radius, the autonomous mobile robot can avoid moving obstacles and reach the destination. To verify the proposed algorithm, use quantitative analysis methods to compare and analyze with existing algorithms. The analysis method compares the length and run time of the proposed algorithm with the length of the path of the existing algorithm based on the absence of a moving obstacle. The proposed algorithm can be avoided by taking into account the relative speed and direction of the moving obstacle, so both the route and the driving time show higher performance than the existing algorithm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.2
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• pp.111-118
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• 1984

On the basis of plasticity theory for porous metal, an analysis of ring compression is carried out, employing the upper bound approach. The plastic flowability and the neutral radius of porous metal ring are calculated and deformation characteristics of power forging are obtained from this result. The experiments on ring compression are carried out for sintered iron porous metal with various relative densities under various friction conditions. A good agreement is observed between the shapes of the calculated curves and the experimental results from the ring compression test. The friction factor for powder metal forming can be determined not only from the relationship between reduction in height and reduction in internal diameter but independently from the relationship between reduction in height and relative density, if the initial relative density is known.