• Journal of Korean Institute of Industrial Engineers
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• v.30 no.1
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• pp.65-75
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• 2004

The enhancement of C2(Command and Control) system will increase effectiveness of individual force power in combat engagement. Especially, available time of a given engaging force and information accuracy are the most influencing factors to increment of combat effectiveness after enhancement of C2 system. In this paper, by using Schutzer's C2 Theory and Measures of Effectiveness, we developed several analytical functions representing the relationships between C2 system enhancement and two most critical variables, available time and information accuracy. As a result of functional analysis, we showed C2 system enhancement and combat effectiveness have positive and non-linear relationship. The higher level of C2 system be required, the better combat effectiveness of force power can be obtained. Additionally, we proposed a proposition that the combat effectiveness of C2 system is more sensitive to available time than to information accuracy, which might be very important issue for further research in this field.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.61-68
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• 2007

When an active muscle is stretched, its steady-state isometric force following stretch is greater than that of a purely isometric contraction as the corresponding muscle length, referred to as force enhancement (FE). The purpose of this study was to investigate possible effects of muscle architecture on the FE. While subject performed maximal isometric dorsiflexion (REF) and isometric-stretch-isometric dorsiflexion (ECC) contractions, ankle joint angle and dorsiflexion torque using a dynamometer and electromyography of the tibialis anterior and the medical gastrocnemius muscles were measure. Simultaneously, real-time ultrasound images of the tibialis anterior were acquired. Regardless of the speed of stretch of the ECC contractions. the torques produced during the isometric phase following stretch ($37.3{\pm}1.5\;Nm$ ($10{\pm}3%$ FE) and $38.3{\pm}1.5$ ($12{\pm}3%$ FE) for the ECC contractions with $15^{\circ}$/s and $45^{\circ}$/s stretch speeds, respectively) were greater than those of the REF contractions ($34.5{\pm}2.5\;Nm$). Moreover, the amount of FE was found to be stretch speed dependent. Angles of pennation ($\alpha$) during the isometric phase following stretch were the same for the REF ($15{\pm}1^{\circ}$) and the ECC ($14{\pm}1^{\circ}$(LS), $15{\pm}1^{\circ}$(LF)). During the same phase, muscle thicknesses were the same ($14.9{\pm}0.6$, and $14.9{\pm}0.5\;mm$ for the REF and the ECC contractions, respectively). For a large limb muscle, the tibialis anterior muscle, a similar amount of force enhancement was observed as did for other human skeletal muscles. Architectural variables, pennation angle and thickness, were not systematically different between the REF and ECC contractions when FE occurred. Therefore, the results of this study suggest that muscle architecture may have little influence on the production of FE.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.803-807
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• 2009

The bobsleigh is a winter sport which use a sled to slide down an ice-covered course. There is a big expectation for having a training environment and being able to train year round. At present, training is very limited due to the season or course facilities. A variety of VR (Virtual Reality) equipment has been developed in recent years, and it is beginning to spread. We have also made our contribution in bobsleigh simulation. The reactive force applied in our bobsleigh simulation is much smaller than that of a real bobsleigh. This paper proposes a method to enhance reactive force of bobsleigh simulation in real time. The reactive force is magnified instantly in the physically-based simulation. The Laplacian filter is applied to the sequence of reactive force, this technique is often used in the field of image processing. The simulation is comprised of four large scale surround screens and a 6-D.O.F. (Degree Of Freedom) motion system. We also conducted an experiment with several motion patterns to evaluate the effectiveness of enhancement. The experimental results proved useful in some cases.

• Journal of Korean Vacuum Science & Technology
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• v.4 no.4
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• pp.102-106
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• 2000

We report scanning force microscope (SFM) observations of enhanced calcite dissolution in aqueous solution due to mechanical stimulation induced by the SFM tip. Images and mechanical treatment were performed in saturated ($\geq$ 60 ${\mu}{\textrm}{m}$) CaCO$_3$ solution adjusted to pH~9. Small area scans of monolayer steps significantly increased the step velocity in the scanned area (in the direction corresponding to dissolution) when the applied contact force is above about 160 nN fer the tips employed. The step velocity could be increased at least an order of magnitude by scanning at even higher contact forces (e.g.,270nN). This enhancement is a function of step orientation relative to the calcite lattice. Indentations near preexisting steps also locally enhance the step velocity. We present evidence that the higher dissolution rates are caused by stress-induced increases in the rate of double-kink nucleation.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.31-37
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• 2001

A study to obtain the enhancement of turbulence at low Reynolds number is carried out by adding ultrasonic force into the jet flow field of a coaxial circular pipe which can afford the sufficient data of flow characteristics with the shear flow and turbulence flow in spite of its simple shape. A coaxial circular flow field is made vertically in a large and transparent acryl tank. The time mean velocity vector, distribution, kinetic energy and turbulence intensity formed in the complex flow field of turbulence enhancement are investigated, observed and discussed at Reynolds number of 2,000, 3,000 and 5,000 by using PIV measurement, in results, the validity of ultrasonic to obtain the enhancement of turbulence is certified.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.7
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• pp.2298-2314
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• 1996

Electric field effect on boiling of refrigerants R11, R113, and FC72 has been investigated experimentally. One purpose of the experimental investigation is to determine the effects of the electrode arrangements on electrohydrodynamic boiling of the above mentioned liquids. The test equipment employed in the experiment consists of a shell and tube heat exchanger with six or six and twelve rows of electrode wires around the tube. It has been found that the applied voltage promotes the boiling heat transfer coefficient except FC72. Boiling heat transfer enhancement obtained is about 230% for R11, 280% for R113. It has also been observed that bubbles detached from the tube aggregate at the place where the electrical gradient force balances with the buoyancy one. These aggregated bubbles force to decrease the boiling heat transfer coefficient as well as to reduce the voltage needed to the dielectric breakdown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.624-627
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• 2002

A study on machining electrode for LEO(Light Emitted Diode) mold with shaped end-mill is presented. The electrode machining by shaped end-mill has been used for maximizing the productivity in manufacture of semiconductor mold. However, it has not been researched systematically for many difficulties such as the making of shaped end-mill, generation of tool path due to distinctive tool geometry, and so on. Tool path is generated on the shaped end-mill geometry and cutting force to provide accurate and efficient machining of electrode. The verification program can drive enhancement of productivity, selecting cutting conditions from experiment function of cutting force. Also, compensation of tooting and machina error can make the electrode accurate by modifying tool path. Therefore, the research on machining with shaped end-mill can contribute to enhancement of accuracy and productivity in building semiconductor mold.

• Journal of computational fluids engineering
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• v.4 no.2
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• pp.9-16
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• 1999

The present study investigates flow character and heat transfer behaviors of viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. An axially-constant heat flux on bottom wall and peripherally constant temperature boundary condition(H1) was adopted. The Reiner-Rivlin fluid model is used as the normal stress model for the viscoelastic fluid and temperature-dependent viscosity model is adopted. The present results show a signifiant change of the main flow field which causes a large heat transfer enhancement. This phenomena can be explained by the combined effect of buoyancy, temperature-dependent viscosity and viscoelastic property on the flow.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.7
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• pp.619-624
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• 2014

The critical heat flux (CHF) on a heat transfer surface with nanostructures is known to be significantly better than that on flat surfaces. Several physical mechanisms have been proposed to explain this phenomenon. However, almost all studies conducted so far have been qualitative, and a generalized theory has not yet been established. In this study, we developed a quantitative mechanism for CHF enhancement on a surface with nanostructures, based on vapor recoil and surface adhesion forces. We focused on the increase in the length of the triple contact line owing to the formation of nanostructures and the adhesion force between them and the liquid.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.943-946
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• 2000

Selective laser sintering(SLS) is a solid freeform fabrication process whereby a part is built layerwise by scanning a powder bed. The properties of metal powder are dependent on the heat, it is not easy to do the exact error compensation with analysis and estimation by modeling. This paper suggests that the error is compensated by experimental method and then the accuracy of shape is enhanced by revising of STL file. Also bonding force is measured by an experiment with change of process path.