• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.61-69
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• 2003

The study is the open area keeping a few visible satellites and the urban area covered with the high building, an electric pole were chosen for evaluation of accuracy of satellite positioning. First, suggest the validity of RTK-GPS, RTK-GPS/GLONASS and compared the accuracy with that of the classical surveying method. As a result. In urban area, in case of real time kinematic positioning when compare between the method combined by GPS/GLONASS and by GPS alone the result of GPS/GLONASS - combination more excellent. And in open ana positioning combined GPS/GLONASS was more excellent than GPS alone in both real time differential and real time kinematic. So, RTK-GPS, RTK-GPS/GLONASS contribute to the digital mapping of Basic map and the existed map necessary for the building of PBLIS to the computerization of cadastral map in the effectiveness in time and in cost and hereafter the combined GPS/TS is expected to contribute to the development of NGIS, Re-investigation of a land register, the execution drawing on site.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1845-1851
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• 2007

Background noise and room reverberation are two causes of degradation in speech in listening situations. Many algorithms developed to enhance reverberant speech. In this paper we propose a dereverberation method for enhancement of speech using modified the linear prediction(LP) residual in reverberant room condition. The proposed dereberberation method based on the fact that the signification excitation of the vocal tract system takes place at the instant of glottal closure in voiced speech. Our method used delay information form each sensor, and we need reverberant signals from 3 sensors. We obtain a new LP residual signal using modified IP residual combination which derived form weighting of the LP residual and the Hilbert transform of LP residual. The nature of the coherently added Hilbert envelop has several large amplitude spikes because of the effects of noise and reverberation. This residual of the clean speech is used to excite the time-varying all-pole filter to obtain the enhanced speech. We achieved simulation of proposed algorithm for performance analysis in reverberation environment. The proposed algorithm improves substantially the quality of reverberant speech.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.755-760
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• 2016

The demand for independent generators using renewable energy has been increasing. Among those independent generators, small wind turbine generators have been actively developed. Permanent magnets are generally used for small wind turbine generators to realize a simple structure and small volume. On the other hand, cogging torque is included due to the structure of the permanent magnet synchronous machine, which can be the source of noise and vibration. The cogging torque can be varied by the shape of the permanent magnet and core, and it can be reduced using the appropriate design techniques. This paper proposes a design technique that can reduce the cogging torque by changing the shape of the permanent magnets for SPMSM (Surface Permanent Magnet Synchronous Motor), which is used widely for small wind turbine generators. Evolution Strategy, which is one of non-deterministic optimization techniques, was adopted to find the optimal shape of the permanent magnets that can reduce the cogging torque. The angle and outer diameter of permanent magnet were set as the design variable. A 300W class wind turbine generator, whose pole/slot combination was 8 poles/18 slots, was designed with the proposed design technique. The properties of the generator, including the cogging torque and output voltage, were calculated. The calculation results showed that the cogging torque of the optimized model was reduced compared to that of the initial model. The design technique proposed by this paper can be an effective measure to reduce the cogging torque.

• Geophysics and Geophysical Exploration
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• v.5 no.3
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• pp.157-168
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• 2002

Improved procedures were implemented in the production of the lithospheric magnetic anomaly map from Magsat satellite magnetometer data of East Asia between $90^{\circ}E-150^{\circ}E$ and $10^{\circ}S-50^{\circ}N$. Procedures included more effective selection of the do·it and dawn tracks, ring current correction, and separation of core field and external field effects. External field reductions included an ionospheric correction and pass-by-pass correlation analysis. Track-line noise effects were reduced by spectral reconstruction of the dusk and dawn data sets. The total field magnetic anomalies were differentially-reduced-to-the-pole to minimize distortion s between satellite magnetic anomalies and their geological sources caused by corefield variations over the study area. Aeromagnetic anomalies were correlated with Magsat magnetic anomalies at the satellite altitude to test the lithospheric veracity of anomalies in these two data sets. The aeromagnetic anomalies were low-pass filtered to eliminate high frequency components that may not be shown at the satellite altitude. Although the two maps have a low CC of 0.243, there are many features that are directly correlated (peak-to-peak and trough-to-trough). The low CC between the two maps was generated by the combination of directly- and inversely-correlative anomaly features between them. It is very difficult to discriminate directly, inversely, and nully correlative features in these two anomaly maps because features are complicatedly correlated due to the depth and superposition of the anomaly sources. In general, the lithospheric magnetic components were recovered successfully from satellite magnetometer observations and correlated well with aeromagnetic anomalies in the study area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.535-539
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• 2010

This paper include to study DoA(Direction of Arrival) for radio collection and monitoring system. The direction finding calculated by applying the CVDF (Correlation Vector Direction Finding) algorithm for the five circular dipole antenna over V / UHF band. To improve the accuracy of direction finding by applying CVDF algorithm needs to obtain ideal phase difference each antennas. However, a circular array antenna phase difference pattern may be distorted on a specific frequency band or to particular direction. The effect of installing each array antennas circularly and the effect of the interference of center pole (located in the center of a circular array antenna mount) may make the distortion of phase pattern. If you use an active antenna instead of passive antenna to obtain good sensitivity, you would measure the more distortion. This paper propose how to change combination of antennas to measure the phase in real-time and how to use antenna beam patterns for minimizing the degradation phenomena at applying simple CVDF algorithm and increasing the direction finding capability.