• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.16-21
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• 2019

Small and medium-sized Korean companies are currently changing their industrial structure faster than in the past due to various environmental factors (such as securing competitiveness and developing excellent products). In particular, the importance of collecting and utilizing data produced in smart factory environments is increasing as diverse devices related to artificial intelligence are put into manufacturing sites. This paper proposes an artificial intelligence-based smart factory model to improve the process of products produced at the manufacturing site with the recent smart factory. The proposed model aims to ensure the increasingly competitive manufacturing environment and minimize production costs. The proposed model is managed by considering not only information on products produced at the site of smart factory based on artificial intelligence, but also labour force consumed in the production of products, working hours and operating plant machinery. In addition, data produced in the proposed model can be linked with similar companies and share information, enabling strategic cooperation between enterprises in manufacturing site operations.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.308-314
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• 2017

PURPOSE. The purpose of this study was to analyze the retention force changes and wear behaviours of double-crown systems over long-term use. MATERIALS AND METHODS. Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of $4^{\circ}$ and $6^{\circ}$. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS. In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the $LL-4^{\circ}$ group (32.89 N-32.65 N), and the lowest retention force values were found in the $ZA6^{\circ}$ group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION. More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.35-40
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• 2020

The ballast layers play a key role in distributing and supporting a trainload. On the other hand, it settles down by dynamic train loading due to large void ratios. Consequently, it requires continuous maintenance. In this paper, ballast layers mixed with three types of specially shaped artificial ballast (AB) (Rectangular, Tetrapod, Hexagonal) were modeled by using a two dimensional DEM (Discrete Element Method). Repeated loading tests were performed to evaluate the settlement behavior of the ballast layers. The smallest settlement was observed in the case of the ballast layer mixed with Tetrapod AB than in other cases, according to an analysis of the force transfer routes. In addition, contact force analysis showed that the Tetrapod AB, which has a concave shape, could easily make small and multi-channel force-transfer routes. This means that the stress in the ballast layer by the train loading transferred through the sleeper uniformly was distributed well by the AB. Therefore, the settlement of the ballast layer mixed with the concave-shaped Tetrapod AB could be reduced effectively under a repeated train loading. The effects of a decrease in settlement of the ballast layer highlight the possibility of a maintenance-free ballasted track.

• Journal of Biomedical Engineering Research
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• v.26 no.6
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• pp.393-398
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• 2005

An electromechanical type is the most useful mechanism in the various pumping mechanisms. It, however, requires a movement converting system including a ball screw, a helical cam, or a solenoid-beam spring, which makes the device complex and may lessen reliability. Thus, the authors have hypothesized that an electromagnetic actuator mechanism can eliminate the movement converting system and that thereby enhance the mechanical reliability and operative simplicity of an electro­pneumatic pump. The purpose of this study was to show a novel application of electromagnetic actuator mechanism in pulsatile pump and to provide preliminary data for further evaluations. The electromagnetic actuator consists of stators with a single winding excitation coil and movers with a high energy density neodymium-iron-boron permanent magnet. A 0.5mm diameter wire was used for the excitation coil, and 1000 turns were wound onto the stators core with parallel. A prototype of extracorporeal electro-pneumatic pump was constructed, and the pump performance tests were performed using a mock system to evaluate the efficiency of the electromagnetic actuator mechanism. When forward and backward electric currents were supplied to the excitation coil, the mover effectively moved back and forth. The nominal stroke length of the actuator was 10mm. The actuator dimension was 120mm in diameter and 65mm in height with a mass of 1.4kg. The prototype pump unit was 150mm in diameter, 150mm in thickness and 4.5kg in weight. The maximum force output was 70N at input current of 4.5A and the maximum pump rate was 150 beats per minute. The maximum output was 2.0 L/minute at a rate of 80bpm when the afterload was 100mmHg. The electromagnetic actuator mechanism was successfully applied to construct the prototype of extracorporeal electro­pneumatic pump. The authors provide the above results as a preliminary data for further studies.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.984-988
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• 2004

This study presents the process of the solenoid parameter estimation of an common-rail injector fer HSDI(High Speed Direct Injection) diesel engines. The EMF(Electromotive Force) and solenoid inductance are the major parameters for presenting the injector dynamics, and also these parameters are estimated by using a multi-layer feedforward artificial neural networks(ANN). The performances of parameter estimators are verified by the simulation with injector model. The feasibility of this methodology is closely examined through the simulation in the various operating points of injector. The simulation results have revealed that estimated parameters show favorable agreements with the common-rail injector model.

• Journal of Welding and Joining
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• v.33 no.4
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• pp.63-67
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• 2015

Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing(ECT) is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. The New ECT sensor which can detect inner defects was developed regardless the condition of surface. This sensor is verified to do experiment which measure the loss of induced electromotive force. The loss of induced electromotive force was measured in 5.4% and this low frequency ECT device can detect internal defects at depth 20 mm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.31-40
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• 1993

This paper deals with static tension analysis method for Floating Tire Breakwater(FTB). FTB can be used for the limited wave height. It is especially focused on Goodyear type FTB easily applied to the breakwater for the fisheries cultivating region. The numerical examples for FTB design procedure was reviewed. It is also studied the static analysis method of offshore catenary spread mooring system. The general calculation procedure for the tension versus excursion curves for the multi-line system using the basic catenary relationship was studied. Calculation results showed good agreement with some existing mooring results. To extend this mooring force calculating method to the floating fisheries caitivating cages, the strength of synthetic fiber was considered. This analysis method can be used to the estimation of the mooring force for the floating structures such as floating breakwaters and floating artificial reefs.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.148-153
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• 2013

This study demonstrates a novel hybrid surface polishing process combining non-traditional electrochemical polishing(ECP) with external artificial ultrasonic vibration. ECP, typical noncontact surface polishing process, has been used to improve surface quality without leaving any mechanical scratch marks formed by previous mechanical processes, which can polish work material by electrochemical dissolution between two electrodes surfaces. This research suggests vibration electrochemical polishing(VECP) assisted by ultrasonic vibration for enhancing electrochemical reaction and surface quality compared to the conventional ECP. The localized roughness of work material is measured by atomic force microscopy(AFM) for detailed information on surface. Besides roughness, overall surface quality, material removal rate(MRR), and productivity etc. are compared with conventional ECP.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.67-72
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• 1998

The paper aims to present a new human-scale haptic advice for virtual environment named Scaleable-SPIDAR (Space Interface Device for Artificial Reality), which can provides different aspects of force feedback sensations, associated mainly with weight, contact and inertia, to both hands within a cave-like space. Tensioned string techniques are used to generate such haptic sensations, while keeping the space transparent and unbulky. The device is scaleable so as to enclose different cave-like working spaces. Scaleable-SPIDAR is coupled with a large screen where a computer generated virtual world is displayed. The used approach is shown to be simple, safe ad sufficiently accurate for human-scale virtual environment.

• The KSFM Journal of Fluid Machinery
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• v.15 no.5
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• pp.54-59
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• 2012

In order to have the high efficiency of aircraft wing and to improve the energy efficiency in field of eco-friendly transportation, the performance characteristics of the aircraft wing were studied with the change of lift to drag ratio through the CFD analysis. The design process was focused on generating the high lift force and low drag force as the lift to drag ratio was increased. In this paper, various dimple patterns were numerically designed to investigate the flow characteristics. Hexagon-and circle-shaped dimples, dimple distance and position were changed as the artificial conditions. The numerical analyses were conducted by using the commercial code, ANSYS CFX. Numerical results dependent on the turbulence intensity and lift to drag ratio distribution were graphically depicted for various dimple patterns.