• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1567-1573
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• 2005

This paper introduces a new active magnetic bearing(AMB) that can provide both radial and axial control functions in one bearing unit without axial disk. It has a structure of double four-pole AMB or a four-pole AMB where each core is split into two axially. The cores have two kinds of coil winding; they independently generate fluxes on the planes perpendicular or parallel to the shaft. For the radial control action, it works just like a conventional four-pole AMB. Meanwhile, for the axial control, it uses the Lorentz force generated by the interaction of the bias flux for radial control and the axial control flux. In this paper, the proposed structure, principle, and design process based on magnetic flux analysis are introduced, and its feasibility is experimentally verified by using a simple PD control algorithm with a feedforward loop to compensate the coupled flux effect.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1835-1841
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• 2017

An improved single-phase full-bridge zero-voltage-switching inverter using a subtractive coupled magnetics is proposed in this paper. The proposed topology overcomes several drawbacks of the conventional ARCPI zero-voltage-switching inverter including two bulky capacitors which can cause problems such as the need for a protection circuit and voltage fluctuation of split capacitors. Also the proposed topology can reduce the number of devices required for ZVS through a simplified auxiliary circuit, thus achieving low cost and small volume and is applicable a modified unipolar PWM scheme. Detail mode analysis and design considerations are provided for optimal efficiency. In the end, the effectiveness and feasibility of the proposed topology are verified experimentally under various conditions.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.115-131
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• 1997

The problem addressed in this paper is to minimize the deviations of workloads assigned to worker and to maximize the total utilizations(degree of skill) between workers and machines simultaneously. Each worker can handle the set of machines with the different degree of skill and each machine has the workloads needed to be processed. Also, each worker has to be assigned to at least one machine with the minimum workload deviation. This problem can be formulated as a preemptive goal programming with generalized assignment constraints. The proposed algorithm consists of two phases. First, a capacitated circulation network is constructed to assign the workers to machines with the maximum total utilizations while considering workloads balance. Then, a refinement process is applied to the split machines to satisfy the feasibility condition. The real industrial application in a plastic extrusion manufacturer is included along with several computational experiments.

• Journal of Periodontal and Implant Science
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• v.48 no.3
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• pp.193-200
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• 2018

Purpose: The present study describes 3 patients with chronic periodontitis and consequent vertical resorption of the alveolar ridge who were treated using implant-based restoration with guided bone regeneration (GBR). Methods: After extraction of a periodontally compromised tooth, vertical bone augmentation using a K-incision was performed at the healed, low-level alveolar ridge. Results: The partial-split K-incision enabled soft tissue elongation without any change in buccal vestibular depth, and provided sufficient keratinized gingival tissue during GBR. Conclusions: Within the limits of this study, the present case series demonstrated that the novel K-incision technique was effective for GBR and allowed normal implant-based restoration and maintenance of a healthy periodontal condition. However, further long-term follow-up and a large-scale randomized clinical investigation should be performed to evaluate the feasibility of this technique.

• Journal of the Korean Ceramic Society
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• v.37 no.2
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• pp.134-139
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• 2000

The main objective of the present investigation is to show the feasibility of combinatorial chemistry by applying this method to phosphor syntehses. In this respect barium hexaaluminate phosphor was prepared by the split-pool combinatorial method, which enabled much more rapid search of optimum compositions of target phosphors than conventional synthetic methods. Barium hexaaluminate phosphors doped with Eu2+ exhibit blue emission while those co-doped with Mn2+ and Eu2+ exhibit green emission. Basically, the phosphor doped with 1.3 mole of Ba and 0.06~0.15 mole of Eu2+ exhibit the maximum value of emission intensity at 435${\mu}{\textrm}{m}$. Under the UV and VUV extitations, the barium hexaaluminate phosphor co-doped with Mn2+ and Eu2+ shows strong green emission.

• Journal of applied mathematics & informatics
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• v.38 no.5_6
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• pp.519-532
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• 2020

In this paper, we first propose a new total variation-based regularization model for image restoration. We next propose a fixed-point-like method for solving the new image restoration model, and then we provide convergence analysis for the fixed-point-like method. To evaluate the feasibility and efficiency of the fixed-point-like method for the new proposed total variation-based regularization model, we provide numerical experiments for several test problems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.629-633
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• 2006

We investigated a new longitudinal acceleration wave decomposition method in time domain. The proposed method separates up- and down-stream waves with an axial strain and axial acceleration measured at a single point on the transmission path. The advantages such as low computation load and easy implementation would be possible by developing time domain under the following assumptions; low frequency range, uniform cross sectional area and elastic wave propagation. We confirmed the feasibility and performance of the method through experiment using Split Hopkinson Pressure Bar (SHPB). The method can be effective in several applications, including active vibration control with wave view point, where real time wave decomposition is necessary.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.13-18
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• 2019

The high energy penalty in amine-based post-combustion CO₂ capture process is hampering its industrial scale application. An advanced process is designed by intensive heat integration within the conventional process to reduce the stripper duty. The study presents the technical feasibility for stripper duty reduction by intensive heat integration in CO₂ capture process. A rigorous rate-based model has been used in Aspen Plus® to simulate conventional and advanced process for a 300 MW coal-based power plant. Several design and operational parameters like split ratio, stripper inter-heater location and flowrate were studied to find the optimum values. The results show that advanced configuration with heat integration can reduces the stripper heat by 14%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.8
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• pp.1457-1471
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• 2011

A method to detect Trojan horses in messaging and Bluetooth in mobile phones by means of monitoring the events produced by the infections is presented in this paper. The structure of the detection approach is split into two modules: the first is the Monitoring module which controls connection requests and sent/received files, and the second is the Graphical User module which shows messages and, under suspicious situations, reports the user about a possible malware. Prototypes have been implemented on different mobile operating systems to test its feasibility on real cellphone malware. Experimental results are shown to be promising since this approach effectively detects various known malware.

• Transactions of Materials Processing
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• v.25 no.5
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• pp.332-337
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• 2016

The automobile cowl cross bar which is a backbone frame part holding electrical and air conditioning components inside the cockpit module has been designed with more complex geometries recently due to demands of its enhanced functions and reduced weight of frame parts. The traditional manufacturing process using welding between tubes with different diameters shows several problems such as poor mechanical characteristics and appearance, etc. Therefore, in this study, one-piece manufacturing processes which can eliminate the welding process were developed by applying the rotary swaging process. CAE analyses were conducted to examine the feasibility of the process and prototypes were manufactured by using a rotary swaging machine with 4 split rotating dies and 12 head rollers. Bending tests of the manufactured prototypes confirmed that the rotary swaging process gives better mechanical properties comparing with the conventional processes.