• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.13-23
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• 2002

This paper presents inverse kinematic and dynamic analyses of HexaSlide type six degree-of-freedom parallel manipulators. The HexaSlide type parallel manipulators (HSM) can be characterized as an architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. In the inverse kinematic analyses, the slider and link motion (position, velocity, and acceleration) is computed given the desired mobile platform motion. Based on the inverse kinematic analysis, in order to compute the required actuator forces given the desired platform motion, inverse dynamic equations of motion of a parallel manipulator is derived by the Newton-Euler approach. In this derivation, the joint friction as well as all link inertia are included. Relative importance of the link inertia and joint frictions on the computed torque is investigated by computer simulations. It is expected that the inverse kinematic and dynamic equations can be used in the computed torque control and model-based adaptive control strategies.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.773-781
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• 2004

This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.773-777
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• 1994

This paper is devoted to the development and performance evaluation of a hard bearing type balancing machine for rigid rotors. The pedestals of the balancing machine are designed to be rigid to be rigid enough to enable the balancing to operate far below the fundamental critical speed. The force measuring method is implemented to the balancing machine. The forces due to unbalance are measured through load cell that are attached to the pedestals. A helical coupling is used for transmitting the driving force from an AC servo motor to the rotor to be balanced. The experimental results show that the current hard bearing type balancing machine can indicate the presence of unbalance beyond 1 .mu. m in specific unbalance unit. The limitation of the current balancing machine is due to the coupling that is likely to make inconsistent offset errors everytime the rotor is connected to the machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.391-395
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• 2002

This paper described about the ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a leaf spring mechanism and a capacitive-type sensor. The contact probe is attached on the z-axis during measurement while aspheric objects are supported on the single point diamond turning machine(SPDTM). The machine xz-axis motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed of On-machine Measurement System in this investigation is capable of providing a repeatability of 20 nanometers with a $\pm$20 uncertainty of 300 nanometers.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.3
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• pp.92-97
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• 2011

In this paper, a controller recognizing human gestures using EMG signal is shown. The tiny and band-type controller is developed for image training to excercise the specific area in the body, and uses a dry-type silver fiber electrode easy to be attached or detached itself to a skin. The captured EMG signals are converted to 10-bit digital values via amplification and frequency filtering processes within the controller, and are transmitted to the server by wireless. As the gesture recognition ratio using the proposed controller on biceps is up to 80%, we expect the practical potential of the controller is very promising.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.2
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• pp.177-184
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• 2017

The Coanda effect is the phenomenon of a fluid jet to stay attached to a curved surface; when a jet stream is applied tangentially to a convex surface, lift force is generated by increase in the circulation. The Coanda effect has great potential to be applied practically applied to marine hydrodynamics where various lifting surfaces are being widely used to control the behavior of ships and offshore structures. In the present study, Numerical simulations and corresponding experiments were performed to ascertain the applicability of the Coanda effect to a horn-type rudder. It was found that the Coanda jet increases the lift coefficient of the rudder by as much as 52% at a jet momentum coefficient of 0.1 and rudder angle of $10^{\circ}$.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.4
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• pp.184-191
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• 2001

This paper proposes a prefilter type velocity compensating control system using modified chaotic neural networks for the trajectory control of robotic manipulator. Since the structure of modified chaotic neural networks(MCNN) and neurons have highly nonlinear dynamic characteristics, MCNN can show the robust characteristics for controlling highly nonlinear dynamics like robotic manipulators. For its application, the trajectory controller of the three-axis robot manipulator is designed by MCNN. The MCNN controller acts as the compensator of the PD controller. Simulation results show that learning error decrease drastically via on-line learning and the performance is excellent. The MCNN controller showed much better control performance and shorter calculation time compared to the RNN controller, Another advantage of the proposed controller could by attached to conventional robot controller without hardware changes.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.405-407
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• 2000

The most generally implemented method to detect the ground speed of the railway vehicles is to use the rotary type speed sensor attached to wheel axle. The Slip or sliding phenomenon on the railway vehicles occurs frequently caused by the weak viscosity of the wheel. Thus, precisely to control the car, the slip/sliding detection system is required. In this paper we proposed for the speed data management system, which uses rotary type speed sensor. Proposed speed management system can detect the slip/sliding with wheel axle as well as correct the generated speed error during in error time, to provide accurate speed and precise location data. The effectiveness for adapting to the railway system is clarified by the computer simulation.

• Journal of the Korean Mathematical Society
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• v.60 no.1
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• pp.167-193
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• 2023

Let f be a self-dual primitive Maass or modular forms for level 4. For such a form f, we define N^s_f(T):=|{ρ ∈ ℂ : |𝕵(ρ)| ≤ T, ρ is a non-trivial simple zero of L_f(s)}|.. We establish an omega result for N^s_f(T), which is $N^s_f(T) = \Omega(T^{\frac{1}{6}-{\epsilon}})$ for any ∊ > 0. For this purpose, we need to establish the Weyl-type subconvexity for L-functions attached to primitive Maass forms by following a recent work of Aggarwal, Holowinsky, Lin, and Qi.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.509-517
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• 2013

The purpose of this study is to assess the applicability of device-type stream coagulation process which combines physiochemical, biological processing for efficient improvement of water quality in small, middle-sized urban streams. The stream purification facility of this study is compose of pressure flotation type Micro Bubble Process(MBP) to remove TSS and TP and conduit line type Attached Microbial Pipe System(AMPS) to remove BOD. Test conditions of each device were set by floating stay time and change of ultra fine bubble injection amount of MBP, and change of AMPS stay time. Also, removal efficiency of pollution sources of each process were assess by change of season. As result of continuous operation of each process, MBP showed a maximum of TSS 83.69%, TP 95.15% process efficiency and AMPS showed a maximum of 52.95% TBOD5 removal efficiency. Also as result of circular operation of each process, MBP showed a maximum of TSS 69.75%, TP 70.17% process efficiency and AMPS showed a maximum of 68.58% TBOD5 removal efficiency. Therefore, it is considered that this stream coagulation process is effective in improving the water quality of streams in urban areas.