• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.88-96
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• 2012

According to development of technology for media, observers try to watch the realities from images, as follows, 3D imaging has been extremely developed. 3D image gives depth in the image, observers feel in nature. Different image perception from left and right eyes make the 3D image. Anaglyph which is one of the ways to make an image of three dimensions is for obtaining an image of three dimensions by using color filter glasses. Anaglyph has a little amount of calculation and is easy to make, and it has a good point that anaglyph can be used in more wide field because it can create an image of three dimensions to the output of print like printed matter. However, the phenomenon of retinal rivalry can cause a feeling of fatigue because a difference of brightness of the left image and the right image happen. The way to reduce this problem is made by cutting down a difference of brightness. In the result, retinal rivalry can be reduced. We reduced a difference of the brightness of the left and the right image by utilizing the brightness and average of the original image to reduce retinal rivalry and we made better colors of anaglyph by using the way that we keep the hue caused by a change of brightness and supplement saturation about color distortion which is created at that time.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.19-30
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• 2012

For digital data compression, the quantization is the main part of the lossy source coding. In order to improve the performance of quantization, the vector quantizer(VQ) can be employed. The encoding complexity, however, exponentially increases as the vector dimension or bit rate gets large. Much research has been conducted to alleviate such problems of VQ. Especially for high bit rates, a constrained VQ, which is called the sample-adaptive product quantizer(SAPQ), has been proposed for reducing the hugh encoding complexity of regular VQs. SAPQ has very similar structure as to the product VQ(PQ). However, the quantizer performance can be better than the PQ case. Further, the encoding complexity and the memory requirement for the codebooks are lower than the regular full-search VQ case. Among SAPQs, 1-SAPQ has a simple quantizer structure, where each product codebook is symmetric with respect to the diagonal line in the underlying vector space. It is known that 1-SAPQ shows a good performance for i.i.d. sources. In this paper, a study on designing 1-SAPQ for the first-order Markov process. For an efficient design of 1-SAPQ, an algorithm for the initial codebook is proposed, and through the numerical analysis it is shown that 1-SAPQ shows better quantizer distortion than the VQ case, of which encoding complexity is similar to that of 1-SAPQ, and shows distortions, which are close to that of the DPCM(differential pulse coded modulation) scheme with the Lloyd-Max quantizer.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.67-74
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• 2008

This paper proposes two peak-windowing algorithms for peak-to-average power reduction(PAPR) of orthogonal frequency division multiple access(OFDMA) downlink systems. The Proposed algorithms mitigate the effect of excessive suppression due to successive peaks or relatively high peaks of the signal. First, multi-stage peak windowing algorithm is proposed, which exploits multiple threshold of target PAPR in order to step down the peaks gradually. Secondary, variable-length peak windowing algorithm is proposed, which adapts the window length with respect to the existence of successive peaks within a half of window length. Therefore, the proposed method reduces the distortion of signal amplitude caused by window overlapping. The proposed algorithms outperform the conventional peak windowing with the aid of window-length adaptation or sequential peak power reduction. Simulation results show the efficiency of the proposed algorithms over OFDMA downlink systems, especially WiBro systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.11
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• pp.14-23
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• 2002

Two implementation methods for SOVA (Soft Output Viterbi Algorithm)of Turbo decoder are applied and verfied. The first method is the combination of a trace back (TB) logic for the survivor state and a double trace back logic for the weight value in two-step SOVA. This architecure of two-setp SOVA decoder allows important savings in area and high-speed processing compared with that of one-step SOVA decoding using register exchange (RE) or trace-back (TB) method. Second method is adjusting the reliability value with a scaling factor between 0.25 and 0.33 in order to compensate for the distortion for a rate 1/3 and 8-state SOVA decoder with a 256-bit frame size. The proposed schemes contributed to higher SNR performance by 2dB at the BER 10E-4 than that of SOVA decoder without a scaling factor. In order to verify the suggested schemes, the SOVA decoder is testd using Xillinx XCV 1000E FPGA, which runs at 33.6MHz of the maximum speed with 845 latencies and it features 175K gates in the case of 256-bit frame size.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.3
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• pp.80-92
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• 2008

Many predominant video coding tools in terms of coding efficiency were adopted in the latest video coding standard, H.264/AVC. Regardless of development of these predominant video coding tools such as the variable block-size motion estimation/compensation, intra prediction based on various directions, and so on, the discrete cosine transform has been continuously used starting from the early video coding standards. Generally, the correlation coefficient of the residual signal is usually less than 0.5 when this residual signal is actually encoded. In this interval of correlation coefficient, the discrete cosine transform does not show the optimal coding gain, and the discrete sine transform which is a sub-optimal transform when the correlation coefficient is in the interval from -0.5 to 0.5 can be used in conjunction with the discrete cosine transform in the video coding. In this paper, an alternative transform that alternatively uses the discrete sine transform and integer cosine transform in H.264/AVC by using rate-distortion optimization is proposed. The proposed method achieves a BD-PSNR gain of up to 0.71 dB compared to H.264/AVC JM 10.2 at relatively high bitrates.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.380-388
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• 2005

This paper presents analysis results of the effects of RF filter characteristics on the system performance of impulse radio. The impulse radio system transmits modulated pulses having very short time duration and information can be extracted in receiver side based on cross-correlation between received and transmitted pulses. Accordingly, the pulse distortion due to in-band group delay variation can cause serious system performance degradation. In general, RF bandpass filters inevitably cause group delay difference to the signal passing through the filter which is proportional to its skirt characteristic due to its resonance phenomenon. For time as well as frequency domain analysis, small signal scattering parameter $S_{21}$ and its Fourier transform are used to characterize output pulse waveform under the condition that the input and output ports are matched. The output pulse waveform of the filter is predicted based on convolution integral between input pulse and filter transfer function, and resulting BER performances in the BPM and PPM based impulse radio system are calculated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1050-1057
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• 2006

This paper proposes a new predistortion linearizer with amplitude modulator and PFG(Polar Function Generator) using second order harmonic signals. This linearizer consists of PFG that combine with in-phase and quadrature-phase of second harmonic signals and amplitude modulator in main path. The predistorted third order intermodulation distortion(IMD3) signals that are generated by amplitude modulator with fundamental and PFG signals, improve a amplifier nonlinear characteristics. The proposed linearizer and amplifier have been manufactured and tested to operate in cellular base-station transmitting band$(869\sim894MHz)$. The test results show that IMD3 can be removed by more than 22.5 dB in case of CW 2-tone signals ${\Delta}f=1$ MHz, and the adjacent channel power ratio(ACPR) also can be improved by more than 8.4 dB for CDMA IS-95 1FA signals.

• The KIPS Transactions:PartD
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• v.17D no.1
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• pp.1-8
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• 2010

Association rule mining techniques enable us to acquire knowledge concerning sales patterns among individual items from voluminous transactional data. Certainly, one of the major purposes of association rule mining is utilizing the acquired knowledge to provide marketing strategies such as catalogue design, cross-selling and shop allocation. However, this requires too much time and high cost to only extract the actionable and profitable knowledge from tremendous numbers of discovered patterns. In currently available literature, a number of interest measures have been devised to accelerate and systematize the process of pattern evaluation. Unfortunately, most of such measures, including support and confidence, are prone to yielding impractical results because they are calculated only from the sales frequencies of items. For instance, traditional measures cannot differentiate between the purchases in a small basket and those in a large shopping cart. Therefore, some adjustment should be made to the size of market baskets because there is a strong possibility that mutually irrelevant items could appear together in a large shopping cart. Contrary to the previous approaches, we attempted to consider market basket's size in calculating interest measures. Because the devised measure assigns different weights to individual purchases according to their basket sizes, we expect that the measure can minimize distortion of results caused by accidental patterns. Additionally, we performed intensive computer simulations under various environments, and we performed real case analyses to analyze the correctness and consistency of the devised measure.

• Journal of radiological science and technology
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• v.42 no.3
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• pp.167-173
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• 2019

The Cobey method and the modified Cobey method are most commonly used in clinical practice. Therefore, the purpose of this study was to investigate the radiological differences between Cobey and modified Cobey and provide radiographic information about changes of hindfoot image with X-ray entrance center and tube angle change in modified Cobey. This study was performed on foot and ankle phantom. First, for image comparison of Cobey and modified Cobey, the images obtained by applying the same X-ray entrance center to the ankle joint were compared and analyzed. Second, in the modified Cobey, the X-ray entrance center is set as ankle joint and lateral malleolus. The X-ray tube angle was varied from $10^{\circ}$ to $40^{\circ}$ at $5^{\circ}$ intervals for each X-ray entrance center. The images obtained by varying the X-ray tube angle from $10^{\circ}$ to $40^{\circ}$ at intervals of $5^{\circ}$ for each X-ray entrance center were compared and analyzed. The irradiation conditions were the same with 110 kVp, 200 mA, 10 ms, and 110 cm of source - image receptor distance (SID). Image evaluation was performed by two radiologists. Measurements were made on the lateral point, middle point, and calcaneus width based on a hypothetical line parallel to the calcaneal tuberosity. Data were analyzed by using descriptive statistics as the mean of the distance to each measurement location. The modified Cobey was longer than the Cobey by an average of 3 to 4 mm lateral and medial points, and the calcaneus width was similar (ICC = 0.939). In modified Cobey method, when the X-ray entrance center is ankle joint, the lateral point is about 3 mm and the medial point is about 4.3 mm longer than lateral malleolus. Also, when the X-ray tube angle is more than $20^{\circ}$, the degree of distortion is large. The ICCs for the lateral, medial point, and calcaneus width were 0.998, 0.961, and 0.997, respectively, as the X-ray entrance center and tube angle were changed. There was no significant difference between Modified Cobey and Cobey. Modified Cobey showed no need to compensate the $20^{\circ}$ detector angle of the Cobey. In addition, we suggest that tube angle should be limited within $20^{\circ}$ when modified Cobey is performed.

• Journal of International Area Studies (JIAS)
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• v.21 no.1
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• pp.39-72
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• 2017

The purpose of this study is to conduct an empirical analysis on the effect of aid proliferation on government spending on health by the recipient nations using panel data and acquire information on the direction of future ODA operations. In this study, calculated excessive foreign aid index with regard to the health sector of Sub-Sahara African nations and conducted an empirical analysis on the effect of aid fragmentation on government spending on health sector. The result of the analysis disclosed that aid fragmentation significantly reduced government spending on health. It is anticipated that such trend came from the mutual pursuit of profit between the attribute (the needs of the donor nation) of ODA projects after new businesses and the governments of recipient nations that want ODA funding. Because competitive and excessive supports in ODA projects induce distortion in the government budget operation of the recipient nations and thereby trigger disutility in ODA projects, Based on the result of the analysis, We proposed to incorporate a more comprehensive deliberation with regard to the capacity of the recipient nations as well as a need for the role of mediating body such as DAC.