• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.413-421
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• 2005

As the population of HDTV is growing, among many useful features of modern set top boxes (STBs) or digital video recorders (DVRs), video browsing, visual bookmark, and picture-in-picture capabilities are very frequently required. These features typically employ reduced-size versions of video frames, or thumbnail images. Most thumbnail generation approaches generate DC images directly from a compressed video stream. A discrete cosine transform (DCT) coefficient for which the frequency is zero in both dimensions in a compressed block is called a DC coefficient and is simply used to construct a DC image. If a block has been encoded with field DCT, a few AC coefficients are needed to generate the DC image in addition to a DC coefficient. However, the bit length of a codeword coded with variable length coding (VLC) cannot be determined until the previous VLC codeword has been decoded, thus it is required that all codewords should be fully decoded regardless of their necessary for DC image generation. In this paper, we propose a method especially for fast DC image generation from an I-frame using multiple-symbol lookup table (mLUT). The experimental results show that the method using the mLUT improves the performance greatly by reducing LUT count by 50$\%$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1852-1857
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• 2007

The SSB modem performs the modulation process which converts the digital voltage level to the audible frequency band signal and the demodulation process which converts reversely the audible frequency signal to the digital voltage level. The modulator and the demodulator are implemented with a single DSP chip. Because of the SSB specific character, the distortion occurs when the frequency is changed. This distortion has no effect on voice communication but it has an significant effect on data communication. In other words, it is impossible to send data stream with adjacent 2 periods. Therefore, in case of using 2-tone FSK, it is needed to send at least 3 periods to transmit 1 bit. Therefore we implemented the modem using modified phase-delay shift keying to transmit 1 tone signal for high speed transmission. In the 1200[bps] mode, it generates 0, $187{\mu}s$, delay time at 1.3kHz symbol frequency, and in the 2400[bps] mode, 0, $70{\mu}s\;130{\mu}s\;200{\mu}s$, delay time at 1.5kHz symbol frequency. Finally, in the maximum 3600[bps] mode, it generates 0, $100{\mu}s\;160{\mu}s\;250{\mu}s$ 2.0kHz symbol frequency. The measured results of the implemented SSB modem shows a good transfer functional characteristic by spectrum analyzer, almost same bandwidth in pass band and 20dB higher SNR comparing the emu FACTOR and American CLOVER and in the experimental transmitting test, we verified the transmitted data is received correctly in platform.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.83-94
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• 2006

This paper describes ATM cell encipherment method using Rijndael Algorithm adopted as an AES(Advanced Encryption Standard) by NIST in 2001. ISO 9160 describes the requirement of physical layer data processing in encryption/decryption. For the description of ATM cell encipherment method, we implemented ATM data encipherment equipment which satisfies the requirements of ISO 9160, and verified the encipherment/decipherment processing at ATM STM-1 rate(155.52Mbps). The DES algorithm can process data in the block size of 64 bits and its key length is 64 bits, but the Rijndael algorithm can process data in the block size of 128 bits and the key length of 128, 192, or 256 bits selectively. So it is more flexible in high bit rate data processing and stronger in encription strength than DES. For tile real time encryption of high bit rate data stream. Rijndael algorithm was implemented in FPGA in this experiment. The boundary of serial UNI cell was detected by the CRC method, and in the case of user data cell the payload of 48 octets (384 bits) is converted in parallel and transferred to 3 Rijndael encipherment module in the block size of 128 bits individually. After completion of encryption, the header stored in buffer is attached to the enciphered payload and retransmitted in the format of cell. At the receiving end, the boundary of ceil is detected by the CRC method and the payload type is decided. n the payload type is the user data cell, the payload of the cell is transferred to the 3-Rijndael decryption module in the block sire of 128 bits for decryption of data. And in the case of maintenance cell, the payload is extracted without decryption processing.

• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.316-326
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• 2013

This study has researched the national expansion, dispersion of nutria and investigated its inhabitation status for the past 3 years. The report has shown that the number of nutria habitat, reported to be distributed in 9 cities or districts in 2010, has been increased to 13 in 2012. In the research of 629 nutria habitats, 95.9% of habitat traces were found in Busan-Kyungnam area. From the research of relative density by location type for the 6 survey areas in these 5 areas above, it was shown 3.98(${\pm}2.56$)ind./100m in 2010, 2.90(${\pm}2.69$)ind./100m in 2011 and 1.39(${\pm}0.66$)ind./100m in 2012. From the research of relative density by habitat types, it was shown 3.48(${\pm}2.15$)ind./100m in palustrine wetland area, $1.01{\pm}(0.25)ind.$/100m in river area and $3.69{\pm}(2.83)ind.$/100m in riverine wetland area. It was shown that the annual average density in the areas has slightly been decreased for the past 3 years between 2010 and 2012. It also reported that the habitat density in the river area is a bit lower than that in the wetland area. Currently it can be determined that the nutria has fully adapted themselves to the various local environments of wetland, river, stream, and so on in Korea and the Relative density could be remarkably increased especially in the favorable condition like a wetland. As the ones living in the area with over-density could be spread out to other areas, the efficient management plan to control should be prepared considering ecological conditions.

• The Korean Journal of Archival Studies
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• no.19
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• pp.103-151
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• 2009

Appraisal in electronic record environments is performed focusing on not content but function in which the records are created. Functional appraisal is practically supported in that electronic records composed of 0 and 1 of the bit-stream is unable to be evaluated individually. But the most important reason functional appraisal is performed in electronic record environments is that functional appraisal can select electronic records which assure business context and recordness, and need to run organization and perform business. In Korea, functional appraisal has adopted in course of renovation of national record and archive management system, but methods and logics of functional appraisal have numerous problems. To do so, this article discusses current appraisal system and methods of korea which has renovated confronting with electronic record environments, and then proposes the improvement directions on appraisal system and methods of Korea in electronic record environments from the perspective of long-term views. In this respect, this article proposes the improvement directions on current appraisal system and methods of Korea as follows. First, business functional analysis of each agency in functional appraisal should greatly strengthen. Second, it is necessary to devise proper methods for selecting primary values at current stage of electronic records, and to reinforce appraisal of records as knowledges and informations. Finally, functional appraisal, which inevitably carries out for appraising electronic records, has defects in aspect of selecting archives important in a national point of views. Therefore this article suggests the necessity of archival appraisal strategies that complement functional appraisal. This appraisal system is able to establish a base of the regime of archival appraisal which will harmonize primary value at current stage with secondary value at non-current stage in a national point of views.