• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1900-1907
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• 2010

In this paper, a recurrent cerebellar modulation articulation control with praticle swarm optimization (PSO) method has been investigated for improvement of noise attenuation performance in active noise control system. For narrow band noise, FXLMS and RCMAC has a partial satisfactory noise attenuation. However, noise attenuation performance is poor for broad band noise and nonlinear path since it has linear filter structure. To improve this problem, a RCMAC with PSO is proposed and it is shown that satisfactory noise attenuation performance is obtained by some simulations in duct system using harmonic motor noise and KTX cabin noise as a noise source.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.2
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• pp.208-214
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• 2008

This paper presents a structural modification for the performance improvement of a grain sorting machine. The grain sorting machine is used to sort abnormal grains from normal grains such as rice or wheat. Vibration is one of main causes to deteriorate the sorting performance of the machine. Based on the finite element analysis and the experimental modal testing, the vibration characteristics were investigated for the sorting machine. Furthermore, in order to improve the sorting performance of the machine, the frame, chute and base plate of the sorting machine were modified by using the results of the vibration analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.710-717
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• 2003

This study aim to find an appropriate window for class rooms to provide proper sound insulation against aircraft noise and to achieve this, measurements were taken of the sound insulation performance of windows with varying thicknesses of inner air space and sound absorption materials in the inner air spaces. As a result of (his study the improvement of the sound insulation performance of windows(single , double and triple window) has been shown through the analysis and the measuring of windows with these characteristics. These results may be applied to the manufacture of window frames and provide data lot the improvement of the sound insulation performance of windows.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.245-246
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• 2016

The condensation performance evaluation is required for improved living environment of apartment housings. In the current condensation performance evaluation process, high demand of manual works and repetitive process cause unexpected risks due to uncertainty and inefficiency by applying 2D CAD drawings in simulation tool. Furthermore, the evaluation requires taking in action responding to the expanding use of BIM. In this study, the analysis of current evaluation process and required functions for the process improvement based on BIM modeling were deducted from interviews with experts. It is expected that the results of this study can be employed to develop of process automation module for condensation simulation evaluation.

• Journal of the Korean Solar Energy Society
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• v.25 no.2
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• pp.71-79
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• 2005

In this study, the ventilation performance of mechanical ventilation system in apartment House was analyzed through model test according to characteristics of air-vent. Then adequate interval of air-vent was suggested using computer simulation which will create comfort environment through improvement of ventilation performance in apartment house. The result of experiment with separation plate to prevent mixture of contaminated exhaust air with fresh supply air, the ventilation efficiency improved about 10%. The result of simulation with horizontal location of exterior air-vent, contaminated exhaust air is mixed regardless of interval variation. Consequently, mixture of the exhaust air can be prevented through locating the supply air vent on the top side and exhaust air vent on the lower side.

• PNF and Movement
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• v.5 no.2
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• pp.11-19
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• 2007

Purpose : The purpose of this study was to investigate the effect of mat activities in PNF on improvement of balance performance in stroke patients. Methods : Included 12 persons with stroke who were living in the community. They participated in exercise class for 60minutes duration three times a week for 6 weeks. Mat activities in PNF program was modified PNF patterns and techniques on various posture. Balance indexes were measured at pre-treatment, post-treatment and follow-up by K.A.T.3000. Results : Balance index scores had larger improvements after 6 weekends of treatment(p<.05) than pre-treatment, also follow-up test(p<.05). Conclusion : The result of this study showed that PNF mat activities intervention can improve balance performance in disabled persons after stroke.

• The KSFM Journal of Fluid Machinery
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• v.14 no.4
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• pp.45-51
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• 2011

The kimchi refrigerator is the electronic home appliance which is used for the maturing and a custody of the kimchi. In this paper, performance improvement of fan and duct system for kimchi refrigerator has been studied by using a commercial CFD code. In order to achieve a improved fan performance, three-dimensional computational fluid dynamics and the Design of Experiments method have been applied. Additionally, to know the optimized duct inlet shape with the optimized fan, the overall performances were calculated with various duct inlet shapes. The final fan and duct system for kimchi refrigerator showed improved performance in efficiency and total head compared with the existing model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.423-430
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• 2000

Future microcellular systems will require distributed network control. A packet-switched network is suitable for this requirement. The packet reservation multiple access(PRMA) is a Reservation-ALOHA like protocol for wireless terminals to transmit packet speech to a base station. It allows spatially distributed users in cellular systems to transmit packeted voice and data to a common base station using a shared channel. In the existing PRMA, the problem is that the voice packets may collide with the data packets due to simultaneous channel access. the problem may be a major performance degradation factor to a voice and data mixed system. We propose a new PRMA method that integrates voice and data traffic efficiently by resolving the collision problem between data and voice packets. The proposed PRMA method gives a performance improvement than the existing PRAMA method in terms of voice packet dropping probability and data delay characteristic. From analytic results, we can confirm that the proposed PRMA method show a performance improvement than the existing PRMA protocol.

• 한국기계연구소 소보
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• s.13
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• pp.87-98
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• 1984

An experimental study carried out to predict the performance characteristics of a high speed planing boat at the two displacements whose hull form shows hard chines form transom to bow. In the resistance test the planing hull model was porpoising at and above 30 knots for both displacements of 30 tons and 24 tons. A small stern wedge was newly designed and attached across hull bottom. The planing hull model with the stern sedge did not show any porpoising up to the speed of 45 knots for both displacements and it analysed results shows the improvement of resistance performance and planing performance comparing with those of original hull form; i.e. for displacement of 30 tons the effective power and trim angle were reduced by 18.9% and 5.71 degrees at the speed of 28 knots, and for the displacement of 24 tons the effective power and trim angle were reduced by 23.63% and 4.37 degrees at the speed of 28 knots, respectively.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.864-866
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• 2003

In this paper, the improvement of control performance for a magnetic levitation system is presented. The model of a single-magnet system with rail is derived. As a conventional controller, PID controller is designed and implemented. This controller has a narrow stability margin due to low-order controller structure so that it cause unstability for a flexible rail. So to improve the control performance and stability margin, a robust controller as a new controller is designed and implemented using a VME-based digital controller. As a result, the controller performance of the new designed controller is better than that of the conventional controller.