• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.763-764
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• 2006

In this paper, optimized model was designed for the starting characteristic of the Single-Phase Line-Start Permanent Magnet Synchronous Motor by using the Design of Experiment. A field pole angle, thickness and distance from center axis of permanent magnet were selected as design factor. We executed the transient state characteristic analysis of 8 test models. The transient state characteristic analysis was executed by using the 2 dimensional Finite Element Method and the Time Difference Method. We checked the fact that the selected design factor affected starting characteristic of the Line-Start Permanent Magnet Synchronous Motor. Depend on this result we found the optimized design point by using the response optimization.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2518-2534
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• 1993

Fracture behavior of carbon/epoxy laminates under pin loading is studied experimentally and analytically. Effects of ratios of specimen width to hole diameter and edge distance to hole diameter on bearing strength are investigated. Characteristic length of the laminates obtained using HK model has good agreement with the experimental data. The larger hole size induced, the lower bearing strength is measured under pin loading . The bearing strength and failure mode could be predicted using HK model and Zhangs analytical solution of stress distribution around a pin loaded hole. Chamis' prediction method of bearing strength is also considered to predict failure mode and bearing strength. A modification of Chamis' method is made using the factor of rupturc. The predicted bearing strength by the modified method is reasonably close to the experimental data.

• International Journal of Control, Automation, and Systems
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• v.2 no.3
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• pp.354-361
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• 2004

To improve fault isolation performance of the Bayes isolator, this paper proposes the Fuzzy-Bayes isolator, which uses the Fuzzy-Bayes classifier as a fault isolator. The Fuzzy-Bayes classifier is composed of the Bayes classifier and weighting factor, which is determined by fuzzy inference logic. The Mahalanobis distance derivative is mapped to the weighting factor by fuzzy inference logic. The Fuzzy-Bayes fault isolator is designed for the BLDC motor fault diagnosis system. Fault isolation performance is evaluated by the experiments. The research results indicate that the Fuzzy-Bayes fault isolator improves fault isolation performance and that it can reduce the transition region chattering that is occurred when the fault is injected. In the experiment, chattering is reduced by about half that of the Bayes classifier's.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.67-70
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• 2005

In this study, an experimental investigation of the strength of R/C columns with 300mm square sections confined by head anchorage bar is presented. This initial phase of research considers only axial loading and consists of a total of 7 column tests. The main variables are distance and anchorage type of transverse reinforcement such as standard hooks and headed bar. The purpose of this study is to investigate the confinement effect and strength increment by head and to propose the confinement model for column using the head at end of lateral tie. Also, the test results for ultimate strength and strength gain factor of columns in this study and previous study is compared with the existing analytical models. Based on the test results, the Saatcioglu's model estimates confinement effects was closed to experimental value and the developed analytical approach considered the head was capable of predicting the strength gain factor results with a resonable accuracy.

• Journal of the Korean housing association
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• v.11 no.1
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• pp.171-181
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• 2000

The purpose of the resent research is to investigate the characteristics of sound insulation at the circular voided concrete slab in the multi-housing. In order to do this research, the method for field measurement of floor impact sound level was used following the Korea Standard F2810-1996. For the multi-housing, three kinds of circular voided concrete slabs are used to measure the characteristics of sound insulation.The results are as follows; 1.The main factor affecting the characteristics of sound insulation at the circular voided concrete slab in the multi-housing is sound-absorbing materials in the circular tube. 2. The main factor to effect the difference of sound pressure level is circular tube in the concrete slab. 3. The forms of circular tubes effect the characteristics of sound insulation at the circular tube. 4. Sound Pressure Level resulting from the piping direction of circular tubes in little different to octave band level.More study will be needed about the depth and distance of sound insulation materials, and the components of sound insulation materials for the multi-housing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.3063-3068
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• 2014

Since the RCS(Radar Cross Section) of target is important factor to determine radar performance, it is important to locate radar where large RCS is observed. However, the distance between the target and the radar is an important factor of the received power, as well as RCS. In this paper, it is calculated that received power from ballistic missile to radar based on different observed position and it is studied that to place radar for high detection efficiency.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.219-222
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• 2004

The effects of short fiber and particle hybrid reinforcement on fatigue crack propagation behaviors in aluminum matrix composites have been investigated. Single and hybrid reinforced 6061 aluminum containing same 20 $Al_2O_3\;volume\%$ with four different constituent ratios of short fibers and particles were prepared by squeeze casting method and tested to check the near-threshold and stable crack growth behavior. The fatigue threshold of the composites increased with portion of particle contents and showed the improved crack resistance especially in low stress intensity range. Addition of particle instead of short fiber also increased fracture toughness due to increase of inter-reinforcement distance. These increase in both fatigue threshold and fracture toughness eventually affected the fatigue crack growth behavior such that the crack growth curve shift low to high stress intensity factor value. Overall experimental results were shown that particle reinforcement was enhanced the fatigue crack resistance over the whole stress intensity factor range.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.885-890
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• 2009

A fault location algorithm using estimated local source impedance after a fault is proposed in this paper. The method uses after fault data only at the local end. It uses the negative sequence current distribution factor for more accurate estimation. The proposed algorithm can keep up with the variation of the local source impedance. Therefore, the proposed algorithm especially is valid for a transmission line interconnected to a wind farm that the equivalent source impedance changes continuously. The performance of the proposed algorithm was verified under various fault conditions using the Simpowersystem of MATLAB Simulink. The proposed algorithm is largely insensitive to the variation in fault distance and fault resistance. The test results show a very high accurate performance.

• Macromolecular Research
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• v.10 no.6
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• pp.297-303
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• 2002

We have investigated the microstructural properties of a weakly charged polyelectrolyte modeled with both Hookean spring and Debye-Huckel potential, by employing a novel hybrid scheme of molecular dynamics (MD) and Monte Carlo (MC) simulations. Although the off-lattice pivot step facilitates the earlier computations stage, it gives rise to oscillations and hinders the stable equilibrium state. In order to overcome this problem, we adopt the MC off-lattice pivot step in early stage only, and then switch the computation to a pure MD step. The result shows that the computational speed-up compared to the previous method is entirely above 10 to 50, without loss of the accuracy. We examined the conformations of polyelectrolyte in solvents in terms of the end-to-end distance, radius of gyration, and structure factor with variations of the screening effects of solvent and the monomer charges. The emphasis can favorably be given on the elongation behavior of a polyelectrolyte chain, with observing the simultaneous snapshots.

• Korean Linguistics
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• v.81
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• pp.267-297
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• 2018

Vowel raising in Korean has been primarily treated as a phonological, categorical change. This study aims to show how the Korean connective suffix {-go} is realized in various environments, and propose a principle of vowel raising based on both acoustic and perceptual data. To that end, we used a corpus of spoken Korean to analyze the types of syntactic constructions, the realization of prosodic boundaries (IP and PP), and the types of boundary tone associated with {-go}. It was found that the vowel tends to be raised most frequently in utterance-final position, while in utterance-medial position the vowel was raised more when the syntactic and prosodic distance between {-go} and the following constituent was smaller. The results for boundary tone also showed a correlation between vowel raising and the discourse function of the boundary tone. In conclusion, we propose that vowel raising is not simply an optional phenomenon, but rather a type of phonetic reduction related to the comprehension of the following constituent.