• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.3 s.345
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• pp.48-58
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• 2006

This paper presents 8x8 two dimensional DCT/IDCT processor of adder-based distributed arithmetic architecture without applying ROM units in conventional memories. To reduce hardware cost in the coefficient matrix of DCT and IDCT, an odd part of the coefficient matrix was shared. The proposed architecture uses only 29 adders to compute coefficient operation in the 2-D DCT/IDCT processor, while 1-D DCT processor consists of 18 adders to compute coefficient operation. This architecture reduced 48.6% more than the number of adders in 8x8 1-D DCT NEDA architecture. Also, this paper proposed a form of new transpose network which is different from the conventional transpose memory block. The proposed transpose network block uses 64 registers with reduction of 18% more than the number of transistors in conventional memory architecture. Also, to improve throughput, eight input data receive eight pixels in every clock cycle and accordingly eight pixels are produced at the outputs.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.1-10
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• 2012

Improving operating frequency of processors is no longer today's issues; a multiprocessor technique which integrates many processors has received increasing attention. Currently, high-performance processors that integrate 64 or 128 cores are developing for large data processing over 2, 4, or 8 processor cores. This paper proposes an optimal many-core processor for synthesizing guitar sounds. Unlike the previous research in which a processing element (PE) was assigned to support one of guitar strings, this paper evaluates the impacts of mapping different numbers of PEs to one guitar string in terms of performance and both area and energy efficiencies using architectural and workload simulations. Experimental results show that the maximum area energy efficiencies were achieved at PEs=24 and 96, respectively, for synthesizing guitar sounds with sampling rate of 44.1kHz and 16-bit quantization. The synthesized sounds were very similar to original guitar sounds in their spectra. In addition, the proposed many-core processor was 1,235 and 22 times better than TI TMS320C6416 in area and energy efficiencies, respectively.

• Journal of The Korean Association For Science Education
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• v.34 no.7
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• pp.647-655
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• 2014

The purpose of this study is to acquire teaching insights for improving scientific literacy by analyzing the effects of scientific communication skills, science process skills, and logical thinking skills of elementary school students on academic achievement level. The participants are 64, sixth grade elementary school students. Survey materials include the results of Scientific Communication Skill Test (SCST), Test of Science Process Skills (TSPS), Group Assessment of Logical Thinking (GALT), multiple choice test & short answer test, descriptive answer test on science, and academic achievement level test on all subjects. Based on these data, the study analyzed the relationships of science process skills, logical thinking skills, and scientific communication skills, and each category's effect on academic achievement level. Furthermore, under the assumption that scientific communication skills are affected by science process skills and logical thinking skills and directly influence the academic level, the research discovered three types of correlations as a structural model. The results show that there are considerable correlations in scientific communication skills, science process skills, and logical thinking skills. Also, these three abilities have meaningful correlations with learner's writing and descriptive question level on science curriculum and overall academic achievement level; the level of correlation differ a bit by subcategory factors. In conclusion, setting the model, science process skills and logical thinking skills influence scientific communication skill, and the skill directly influences the learner's academic level. Further analysis of the results show that scientific communication skill influences the academic achievement level of all subjects the most.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.8-15
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• 2009

Side-channel attacks including the differential power analysis attack are often more powerful than classical cryptanalysis and have to be seriously considered by cryptographic algorithm's implementers. Various countermeasures have been proposed against such attacks. In this paper, we deal with the masking method, which is known to be a very effective countermeasure against the differential power analysis attack and propose new gate-level conversion methods between Boolean and arithmetic masks. The new methods require only 6n-5 XOR and 2n-2 AND gates with 3n-2 gate delay for converting n-bit masks. The basic idea of the proposed methods is that the carry and the sum bits in the ripple adder are manipulated in a way that the adversary cannot detect the relation between these bits and the original raw data. Since the proposed methods use only bitwise operations, they are especially useful for DPA-securely implementing cryptographic algorithms in hardware which use both Boolean and arithmetic operations. For example, we applied them to securely implement the block encryption algorithm SEED in hardware and present its detailed implementation result.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.212-224
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• 1998

There are two major factors of degrading the performance in the forward link of DS/CDMA systems. One is the multiple access interference (MAI) caused by using the same frequency bands simultaneously and the other is the multipath lading due to multipath propagation. PN codes which have minimum cross correlation properties among spread spectrum codes are necessary to reduce the MAI. In the conventional IS-95A system, the PN sequence has the period of $2^{15}$ and is of the length of 64 chips for spreading each data. In this case, since the length of PN code per bit is very short compared to the period of the PN code, the performance of the conventional system is not satisfied in view of suppressing the multipath interference. However, the correlation property of the PN codes at the demodulation can be improved by increasing the interval of Integration at the demodulation. This paper proposes a demodulation method to reduce the cross correlation among PN codes. The performance of the proposed demodulation method is investigated through computer simulations. We used multipath Ray lading channel and AWGN channel in the simulation. Our simulation results show the improved performance of $0.25{\sim}0.5dB$ SNR in a given BER compared to the conventional demodulation scheme.

• Journal of the Korean earth science society
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• v.28 no.4
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• pp.415-430
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• 2007

The purpose of this study was to investigate the characteristics of high school students' conceptual understanding about minerals and rocks. A questionnaire was developed to examine students' conceptions of minerals and rocks. The data were collected from 93 students in 10th and 119 students in 11th grades in a high school. The result showed that students' understanding of minerals and rock was on the moderate level. The 10th grade students showed a relatively lower level of understanding about igneous rocks while the degree of the 11th graders' understanding about certain concepts related with melting point in the rock domain was a little bit lower than the average. Although the understanding levels between the two grade levels were similar, there were some items for which students understanding seemed to be more sophisticated with the grade. In the questions about the characteristic of basalt surface, however, the frequencies of non-scientific conceptions were not decreased, rather increased along with the grade. It was also found that the conceptions students acquired from other science lessons as well as earth science classrooms did rather interfere with students' construction of the scientific concepts of minerals and rocks even though sometimes they were helpful for learning. It was suggested that the teachers should understand that some specific terms in earth science have different meanings as they were used in other subjects.

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.59-68
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• 2013

Focal mechanism solutions in the southwestern region of the Korean Peninsula ($34^{\circ}N-36^{\circ}N$, $126^{\circ}E-128^{\circ}E$) were obtained from the analysis of the recent 22 earthquakes ($M{\geq}2.0$) occurred from January, 2005 to March, 2011. The spatial differences between the epicenters recalculated by this study and those by KMA (Korea Meteorological Administration) and KIGAM (Korea Institute of Geoscience and Mineral Resources) are less than $0.05^{\circ}$, indicating a small deviation. However, they become a little bit larger in the coastal area due to a biased arrangement of seismic stations. Redetermined depths of hypocenters show a difference less than 12.7 km by comparison with the depth data announced by KIGAM. Most epicenters in inland area are located closely to the lineaments. Fault plane solutions were obtained from the analysis of P and SH wave polarities, and SH/P amplitude ratios. They show strike-slip faulting or strike-slip faulting with reverse components dominantly. The P-axes trends are mainly ENE-WSW or E-W directions. The direction of fault plane and auxiliary plane with 'NNE-SSW and WNW-ESE' or 'NE-SW and NW-SE' are dominant and almost parallel to the general trends of lineaments in the study area.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.13-22
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• 2004

This paper drives the exact expression of bit error rate(BER) performance for successive interference cancellation(SIC) algorithm against multipath interference components in a high-speed downlink packet access(HSDPA) system of W-CDMA downlink and the BER performance is evaluated by numerical analysis. Numerical results showed that the average BER performance is rapidly saturated in terms of increasing the number of multipath and is revealed significant improvement for improvement Processing gain(PG). For example, the average BER Performance of the SIC algorithm is superior to the performance of conventional scheme by more than 7dB and 1.4dB for processing gain PG=54 and 128 under the two-path channel and average BER=$1.0{\times}10^{-3}$, respectively. This results also indicated that the average BER saturation is occurred at nearly one weight factor which is assigned to pilot and data channels. Likewise, the average BER performance is greatly degraded due to increasing the interference power in proportional to the number of multipath with increasing multicode K. And the smaller multipath fading channel gain is arrived later, the more the average BER performance is improved. The results of performance analysis in this paper indicated that the multipath interference cancellation is required to improve the BER performance in a HSDPA system under multicode for high-speed packet transmission, low spreading factor, and multipath fading channel.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.26-31
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• 2009

A new LFSR based test compression scheme is proposed by reducing the maximum number of specified bits in the test cube set, smax, virtually. The performance of a conventional LFSR reseeding scheme highly depends on smax. In this paper, by using different clock frequencies between an LFSR and scan chains, and grouping the scan cells, we could reduce smax virtually. H the clock frequency which is slower than the clock frequency for the scan chain by n times is used for LFSR, successive n scan cells are filled with the same data; such that the number of specified bits can be reduced with an efficient grouping of scan cells. Since the efficiency of the proposed scheme depends on the grouping mechanism, a new graph-based scan cell grouping heuristic has been proposed. The simulation results on the largest ISCAS 89 benchmark circuit show that the proposed scheme requires less memory storage with significantly smaller area overhead compared to the previous test compression schemes.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.357-364
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• 2012

For this study, real estate brokerage services to customers how to evaluate quality factors and quality factors important for studying about what is preferred. Real estate brokerage service quality factors, the expertise of brokers, dealers sales skills, a sense of responsibility of traders, brokerage firm's position, whether or not participating were chosen franchise. Looking at the findings, and customer service quality factors, the five kinds of real estate brokers a sense of responsibility to be the most important quality factors were analyzed as a favorite, followed by the expertise of brokers, sales skills brokers, brokerage firm's presence, a franchise analysis of whether the order has been participating. As the results of this study, the traders as traders sense of responsibility and expertise and strive to improve, friendly servece and act as an active intermediarv will need to improve sales skills. Continuous promotion of the brokerage firm's position is shown to be critical, franchise affiliated businesses in order to make use of an efficient information network of the Internet is seen to be in need of improvement. This paper, we have experienced a real estate brokerage contracts require customers a service directly to find out whether the data obtained through interviews with the empirical analysis is Therefore, work-related departments of Ministry of Land and brokerage herein with reference to the Association to take measures to Once you have contributed little bit. Brokerage industry and the traders themselves, as well as the competition is to the straight ahead Do not look at a value for the development of brokerage will be constantly working.