• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.30-35
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• 2010

As of today, Frequency Hopping techniques are widely used for over-channel interference and anti-jamming communication systems. In this paper, analysis the performance of robustness on the focus of some general jamming channel. In FH/SS systems, usually SFH(Slow Frequency Hopping) and FFH(Fast Frequency Hopping) are took up on many special communication systems, the SFH, FFH are also combined with a channel diversity algorithm likes NED(Normalized Envelop Detection), EGC(Equal Gain Combines) and Clipped Combines to overcome jammer's attack. This paper propose Adaptive-NED and shows A-NED will be worked well than the others in the some general jamming environments.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3145-3147
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• 2000

A passive RFID system consists of reader and tag. Reader is required the filter to modulate the data from backscattering signal which is transmitted by tag. The filter in the reader consists of envelope detector, amplifier, filter, and pulse shaping circuit, In this paper, design and analysis of filter in the RFID system which is operated at l3.56MHz carrier and 70KHz backscattering signal frequency is presented and is confirmed by simulation using Pspice.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.251-258
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• 2009

Building-Integrated Photovoltaics (BIPV) is a photovoltaic (PV) technology which can be incorporated into the roofs walls of both commercial and domestic buildings to provide a source of electricity. BIPV systems can operate as a multi-functional building components, which generates electricity and serves as part of building envelope. It can be regarded as a new architectural elements, adding to the building's aesthetics. Applying PV modules on roof has an advantage over wall applications as they seem to receive more solar radiation on PV modules. There are various types of PV applications on building roofs: attached, on-top and integrated. This paper describes the classification and characteristics of PV applications on roofs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1312-1319
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• 1988

Internal gear is the important part of the planetary reduction gear system. This study aims at developing the numerical analysis method for design of spherical hob to manufacture internal gear. Methods of calculation of hob tooth profile, generating tooth profile and tooth profile errors such as the errors of pressure angle, tooth thickness and pitch of spherical hob must be made smaller than those of standard tooth profile. And, the smaller the pressure angle and the number of equivalent pinion tooth become, the larger the tooth profile errors are. One design example of spherical hob is proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1074-1084
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• 1999

In this paper the bit error probability of noncoherent M-ary FSK system is derived from the probability density function of the envelope of the received signal over a frequency-nonselective slowly m-distributed Nakagami fading channel. Also, the performance of coherent M-ray FSK system is theoretically analyzed, using union bound over the similar fading channel. Then we compare uncoded performance results for M-ary FSK and DPSK signals in Nakagami fading channel.

• Proceedings of the KIEE Conference
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• summer
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• pp.1483-1485
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• 2004

Photovoltaic(PV) technology is a popular part of building vocabulary. It can be used today on both existing and new buildings. Its use in the building envelope is very varied and open ways, such as roofing materials, facades, skylights and shading systems, for creative designers. So, to activate this systems demand appropriate sources of information, performance data of elements and design tools offering architects and designer. Therefore this paper describe application elements for BIPV system and then predict improvement in the generated electric power performance of balcony BIPV system.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.255-262
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• 2002

We present the infrared spectra of Herbig Ae/Be stars including the Infrared Space Ob-servatory (ISO) data. To investigate the overall properties of their circumstellar dust envelope and/or disk, we combine the IR spectra with photometric data ranging from the UV through the optical into the sub-mm region. We study the general characteristics of the spectral energy distributions using simple analysis. We plot the positions on the HR-diagram to compare with the theoretical pre-main-sequence evolution tracks.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.37-44
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• 2002

An echo signal in the active sonar using a high frequency is mainly formed of a specular reflection from the surface of an object along with several equivalent scatter inside, which are characterized by the spatial distribution of the highlights on the object. This thesis proposed a model in which the synthesized echo signal can be expressed as a distributed simulated target. The proposed model is obtained after composing a signal based on the movement of highlights relative to the aspect angle from the discontinuous point of an external hull with a strong reflection from a spheroid underwater target. Because the proposed algorithm includes a synthesis of the signals related to the highlight spacial distribution, it can be applied to all kinds of systems used at a short range, and similar results were obtained to the actual measured results of all reflected signals in previous literature referring to the irregular factor application of an envelope.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.253-256
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• 2010

Since the amplitude of voiced fall off at about -20dB/decade, dynamic range is often compressed prior to spectral analysis so that details at weak, high frequencies may be visible. Preemphasizing the speech, either by differentiating the analog speech $s_a$(t) prior to A/D conversion or by differencing the discrete-time s(n)=$s_a$(nT), compensating for falloff at high frequencies. The most common form of preemphasis is y(n)=s(n)-As(n-1), where A typically lies between 0.9 and 1.0 and reflects the degree of pre-emphasis. In this paper, we proposed that A is adjusted at each time by measuring the slope of envelope in frequency domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.331-337
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• 2013

Acoustic Emission technique is widely applied to develop the early fault detection system, and the problem about a signal processing method for AE signal is mainly focused on. In the signal processing method, envelope analysis is a useful method to evaluate the bearing problems and Wavelet transform is a powerful method to detect faults occurred on rotating machinery. However, exact method for AE signal is not developed yet. Therefore, in this paper two methods which are Hilbert transform and DET for feature extraction. In addition, we evaluate the classification performance with varying the parameter from 2 to 15 for feature selection DET, 0.01 to 1.0 for the RBF kernel function of SVR, and the proposed algorithm achieved 94% classification accuracy with the parameter of the RBF 0.08, 12 feature selection.