• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.30-38
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• 2006

A new calibration method for five-hole pressure probe is presented. This method provides accuracies better than those based on the traditional regression method. The calibration algorithm uses a single sector interpolation response surface calculated by comparing the regression curve fits with the actual calibration data. A five-hole pressure probe with hemispherical tip was fabricated and calibrated at Reynolds number of $4.11{\times}10^6$/m and flow angle of ${\pm}48$ degrees. Two data prediction models, the least-square regression and a single sector error interpolation, were evaluated. The comparison of these two calibration methods to a five-hole probe is described and discussed. An evaluation of the calibration accuracy is also given.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.791-802
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• 2010

Recent prevalence of progressive scan display such as LCD TV demands the quality improvement of existing deinterlacing techniques that convert interlaced scan images including HDTV broadcasting to progressive scan images. In this paper, we proposea motion adaptive deinterlacing technique which can be used for spatial methods, temporal methods, and the spatial-temporal methods can be used for the deinterlacing techniques selectively based on the threshold values calculated by the statistics of motion in the video contents. We also propose an improved spatial deinterlacing technique that adaptively use M-ELA and DOI based on the slant of edges that are obtained by Sobel operation. The improved picture quality of the proposed algorithm is confirmed by objective and subjective quality tests on many test image sequences.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.102-109
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• 2009

In this paper, we present an algorithm which generates the impossible drawings after the manner of M.C. Escher. A class of the impossible drawings, focused on this paper, depicts the non-realistic configuration such that an ascent (or a descent) looks like keeping on permanently with a height-deceptive loop. We analyze the fact that the ascending direction in the non-realistic illustrations comes not from the physical heights of the objects but from the artist's intended forwarding direction about the loop, which does not have any physical sense of depths. The basic idea to support such impossible drawings is to use a loop of layered depth images (LDIs), where several LDIs are arranged along with the forwarding direction of the loop while having the physically constant heights. The height-deception between two adjacent objects comes from the layer values in the LDIs. In this paper, we propose a NPR system which can manipulate a shape of the loop and layer values of the LDIs and demonstrate several impossible drawings results generated by using our system.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.333-340
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• 2009

MR compatible coaxial-slot antenna for microwave hyperthermia was developed while its structure and size of each part were determined by computer simulation using finite element method(FEM). Its local heating performance was evaluated using tissue-mimic phantom and swine muscles. 2% agarose gel mixed with 6mM/$\ell$ $MnCl_2$ as a biological tissue-mimic phantom was heated by the proposed antenna driven by a 2.45GHz microwave generator. The temperature changes of the phantom were monitored using multi-channel digital thermometer at the distance of 0mm, 5mm, 10mm and 20mm from the tip center of the antenna. Also muscle tissue of swine was heated for 2 and 5minutes with 50W and 30W of microwave generator powers, respectively, to evaluate the local heating performance of the antenna. MRI compatibility was also verified by acquiring MR images and MR temperature map. MR signals were acquired from the agarose gel phantom using $T2^*$ GRE sequence with 1.5T clinical MRI scanner(Signa Echospeed, GE, Milwaukee, WI, U.S.A.) at Pusan Paik Hospital and were transferred to PC in order to reconstruct MR images and temperature map using proton resonance frequency(PRF) method and laboratory-developed phase unwrapping algorithm. Authors found that it has no severe distortion due to the antenna inserted into the phantom. Finally, we can conclude that the suggested coaxial-slot antenna has an excellent local heating performance for both of tissue-mimic phantom and swine muscle, and it is compatible to 1.5T MRI scanner.

• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.307-315
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• 2008

In this paper, we developed a visual-auditory cue software for reading training of motor speech disorder patients. Motor speech disorder patients can use the visual and/or auditory cues for reading training and improving their symptom. The software provides some sentences with visual-auditory cues. Our sentences used for reading training are adequately comprised on modulation training according to a professional advice in speech therapy field. To ameliorate reading skills we developed two algorithms, first one is automatically searching the starting time of speech spoken by patients and the other one is removing auditory-cue from the recorded speech that recorded at the same time. The searching of speech starting time was experimented by 10 sentences per 6 subjects in four kinds of noisy environments thus the results is that $7.042{\pm}8.99[ms]$ error was detected. The experiment of the cancellation algorithm of auditory-cue was executed from 6 subjects with 1 syllable speech. The result takes improved the speech recognition rate $25{\pm}9.547[%]$ between before and after cancellation of auditory-cue in speech. User satisfaction index of the developed program was estimated as good.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.72-79
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• 2010

In this paper, we propose the data cache architecture with a write buffer for a 32bit asynchronous embedded processor. The data cache consists of CAM and data memory. It accelerates data up lood cycle between the processor and the main memory that improves processor performance. The proposed data cache has 8 KB cache memory. The cache uses the 4-way set associative mapping with line size of 4 words (16 bytes) and pseudo LRU replacement algorithm for data replacement in the memory. Dirty register and write buffer is used for write policy of the cache. The designed data cache is synthesized to a gate level design using $0.13-{\mu}m$ process. Its average hit rate is 94%. And the system performance has been improved by 46.53%. The proposed data cache with write buffer is very suitable for a 32-bit asynchronous processor.

• Journal of Astronomy and Space Sciences
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• v.25 no.3
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• pp.283-290
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• 2008

Satellite formation flying can provide the platform for interferometric observation to acquire the precise data and ensure the flexibility for space mission. This paper presents development and verification of an algorithm to estimate the baseline between formation flying satellites. To estimate a baseline(relative navigation) in real time, EKF(Extended Kalman Filter) and UKF(Unscented Kalman Filter) are used. Measurements for updating a state-vector in Kalman Filter are GPS single difference data. In results, The position errors in estimated baseline are converged to less than ${\pm}1m$ in both EKF and UKF. And as using the two types of Kalman filter, it is clear that the unscented Kalman filter shows a relatively better performance than the extended Kalman filter by comparing an efficiency to the model which has a non-linearity.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.92-99
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• 2007

This paper presented a low power design of a 32bit block cypher processor reduced from the original 128bit architecture. The primary purpose of this research is to evaluate physical implementation results rather than theoretical aspects. The data path and diffusion function of the processor were reduced to accommodate the smaller hardware size. As a running example demonstrating the design approach, we employed a modified ARIA algorithm having four S-boxes. The proposed 32bit ARIA processor comprises 13,893 gates which is 68.25% smaller than the original 128bit structure. The design was synthesized and verified based on the standard cell library of the MagnaChip's 0.35um CMOS Process. A transistor level power simulation shows that the power consumption of the proposed processor reduced to 61.4mW, which is 9.7% of the original 128bit design. The low power design of the block cypher Processor would be essential for improving security of battery-less wireless sensor networks or RFID.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1143-1150
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• 2000

A dual-mode multiplier (DMM) that performs single- and double-precision multiplications has been designed using a $0.25-\mum$ 5-metal CMOS technology. An algorithm for efficiently implementing double-precision multiplication with a single-precision multiplier was proposed, which is based on partitioning double-precision multiplication into four single-precision sub-multiplications and computing them with sequential accumulations. When compared with conventional double-precision multipliers, our approach reduces the hardware complexity by about one third resulting in small silicon area and low-power dissipation at the expense of increased latency and throughput cycles. The DMM consists of a $28-b\times28-b$ single-precision multiplier designed using radix-4 Booth receding and redundant binary (RB) arithmetic, an accumulator and a simple control logic for mode selection. It contains about 25,000 transistors on the area of about $0.77\times0.40-m^2$. The HSPICE simulation results show that the DMM core can safely operate with 200-MHZ clock at 2.5-V, and its estimated power dissipation is about 130-㎽ at double-precision mode.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.417-425
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• 2012

It is well known that GPS cannot provide positioning results if sufficient number of visible satellites are not available. To overcome this weak point, attentions have been recently moved to hybrid positioning methods that augments GPS with other sensors. As an extension of hybrid positiong methods, this paper proposes a new method that combines GPS and vision sensor to improve availability and accuracy of land vehicle positioning. The proposed method does not require any external map information and can provide position solutions if more than 2 navigation satellites are visible. To evaluate the performance of the proposed method, an experiment result with real measurements is provided and a result shows that accumulated error of n-axis is almost 2.5meters and that of e-axis is almost 3meters in test section.