• The KIPS Transactions:PartB
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• v.10B no.6
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• pp.673-680
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• 2003

In this paper, we study the enhancement of VQ (Vector Quantization) design for text independent speaker recognition. In a concrete way, we present a non-iterative method which makes a vector quantization codebook and this method performs non-iterative learning so that the computational complexity is epochally reduced The proposed Classified Space VQ (CSVQ) design method for text Independent speaker recognition is generalized from Semi-noniterative VQ design method for text dependent speaker recognition. CSVQ contrasts with the existing desiEn method which uses the iterative learninE algorithm for every traininE speaker. The characteristics of a CSVQ design is as follows. First, the proposed method performs the non-iterative learning by using a Classified Space Codebook. Second, a quantization region of each speaker is equivalent for the quantization region of a Classified Space Codebook. And the quantization point of each speaker is the optimal point for the statistical distribution of each speaker in a quantization region of a Classified Space Codebook. Third, Classified Space Codebook (CSC) is constructed through Sample Vector Formation Method (CSVQ1, 2) and Hyper-Lattice Formation Method (CSVQ 3). In the numerical experiment, we use the 12th met-cepstrum feature vectors of 10 speakers and compare it with the existing method, changing the codebook size from 16 to 128 for each Classified Space Codebook. The recognition rate of the proposed method is 100% for CSVQ1, 2. It is equal to the recognition rate of the existing method. Therefore the proposed CSVQ design method is, reducing computational complexity and maintaining the recognition rate, new alternative proposal and CSVQ with CSC can be applied to a general purpose recognition.

• Journal of KIISE:Software and Applications
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• v.34 no.5
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• pp.397-406
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• 2007

The problem of finding an optimal alignment between sequence A and B can be solved by dynamic programming algorithm(DPA) efficiently. But, if the length of string was longer, the problem might not be solvable because it requires O(m*n) time and space complexity.(where, $m={\mid}A{\mid},\;n={\mid}B{\mid}$) For space, Hirschberg developed a linear space and quadratic time algorithm, so computer memory was no longer a limiting factor for long sequences. As computers's processor and memory become faster and larger, a method is needed to speed processing up, although which uses more space. For this purpose, we present an algorithm which will solve the problem in quadratic time and linear space. By using division method, It computes optimal alignment faster than LSA, although requires more memory. We generalized the algorithm about division problem for not being divided into integer and pruned additional space by entry/exit node concept. Through the proofness and experiment, we identified that our algorithm uses d*(m+n) space and a little more (m*n) time faster than LSA.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.6
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• pp.293-303
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• 2008

As the computing environment moves to the wireless and handheld system, the power efficiency is getting more important. That is the case especially in the embedded hand-held system and the power consumed by the memory system takes the second largest portion in overall. To save energy consumed in the memory system we can utilize low power mode of SDRAM. In the case of RDRAM, nap mode consumes less than 5% of the power consumed in active or standby mode. However hardware controller itself can't use this facility efficiently unless the operating system cooperates. In this paper we focus on how to minimize the number of active units of SDRAM. The operating system allocates its physical pages so that only a few units of SDRAM need to be activated and the unnecessary SDRAM can be put into nap mode. This work can be considered as a generalized and system-wide version of PAVM(Power-Aware Virtual Memory) research. We take all the physical memory into account, especially buffer cache, which takes an half of total memory usage on average. Because of the portion of buffer cache and its importance, PAVM approach cannot be robust without taking the buffer cache into account. In this paper, we analyze the RAM usage and propose power-aware page allocation policy. Especially the pages mapped into the process' address space and the buffer cache pages are considered. The relationship and interactions of these two kinds of pages are analyzed and exploited for energy saving.

• Korean Journal of Cognitive Science
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• v.19 no.2
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• pp.143-161
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• 2008

The goal of this paper is to extract the hyponymy relation between words in the corpus. Adopting the basic algorithm of Hearst (1992), I propose a method of pattern-based extraction of semantic relations from the corpus. To this end, I set up a list of hypernym-hyponym pairs from Sejong Electronic Dictionary. This list is supplemented with the superordinate-subordinate terms of CoroNet. Then, I extracted all the sentences from the corpus that include hypemym-hyponym pairs of the list. From these extracted sentences, I collected all the sentences that contain meaningful constructions that occur systematically in the corpus. As a result, we could obtain 21 generalized patterns. Using the PERL program, we collected sentences of each of the 21 patterns. 57% of the sentences are turned out to have hyponymy relation. The proposed method in this paper is simpler and more advanced than that in Cederberg and Widdows (2003), in that using a word net or an electronic dictionary is generally considered to be efficient for information retrieval. The patterns extracted by this method are helpful when we look fer appropriate documents during information retrieval, and they are used to expand the concept networks like ontologies or thesauruses. However, the word order of Korean is relatively free and it is difficult to capture various expressions of a fired pattern. In the future, we should investigate more semantic relations than hyponymy, so that we can extract various patterns from the corpus.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.258-266
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• 2011

AR(Augmented Reality) technology is now easily shown around us with respect to its applicable areas' being spreaded into various shapes since the usage is simply generalized and many-sided. Currently existing camera vision based AR used marker based methods rather than using real world's informations. For the marker based AR technology, there are limitations on applicable areas and its environmental properties that a user could immerse into the usage of application program. In this paper, we proposed a novel AR method which users could recognize objects from the real world's data and the related 3-dimensional contents are also displayed. Those are done using image processing skills and a smart mobile embedded camera for terminal based AR implementations without any markers. Object recognition is done from the comparison of pre-registered and referenced images. In this process, we tried to minimize the amount of computations of similarity measurements for improving working speed by considering features of smart mobile devices. Additionally, the proposed method is designed to perform reciprocal interactions through touch events using smart mobile devices after the 3-dimensional contents are displayed on the screen. Since then, a user is able to acquire object related informations through a web browser with respect to the user's choice. With the system described in this paper, we analyzed and compared a degree of object recognition, working speed, recognition error for functional differences to the existing AR technologies. The experimental results are presented and verified in smart mobile environments to be considered as an alternate and appropriate AR technology.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.293-298
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• 2012

Purpose: We compared static retinoscopy in eyes opened with cycloplegic refraction depending on the hyperopia for school-aged children. Methods: There were 59 eyes (30 patients) who were divided into 3 groups - the mild hyperopia (+0.25 D ~ +1.00 D), moderate hyperopia (+1.25 D ~ +2.00 D) and high hyperopia (+2.25 D or more). They all had 0.8 visual acuity or more. Autorefraction and retinoscopy were performed prior to cycloplegic refraction, and then copmared with manifest refraction and cycloplegic refraction. Results: Hyperopia measured with static retinoscopy tends to be measured higher than manifest refraction for school-aged children. Changes of spherical power was statistically significant (p < 0.001). Changes of astigmatism was not statistically significant (p > 0.05). Conclusions: The difference between cycloplegic refraction and static retinoscopy was not significant for hyperopic school-aged children. The use of retinoscopy was limited for opticians because of legal constraints. The usage of static retinoscopy in eyes opened for optician should be generalized under the conditions not using the cycloplegic.

• Journal of Korean Society of Forest Science
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• v.69 no.1
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• pp.42-50
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• 1985

The vegetation of common Cryptomeria (Cryptomeria japonica D. Don) stands planted in Chonnam- province was investigated to obtain the fundamental informations for evaluation of suitable site and the improvement of managing method of the Cryptomeria stands in this region. The results investigated were summarized as follows; 1) The growth condition of common Cryptomeria planted 21-25-year-old stands was similar that of same species growing in Akidaken-district in Japan, while the growth condition of 51-58-year-old stands was not so good as that of Japanese. 2) Total number of plant species was 256. The number of floristic composition varied in the range of 42-99- species, which should be mere than those of Japanese. 3) The investigated sites were located in temperate southern part and in subtropic northern part of Korean peninsular. The types of understory vegetation were classified from I to IV class. 4) From the results of high max. possible diversity (H' max), and dominance (1-J') and from the low simple dominance (${\lambda}$) and evenness (J'), It could be concluded that vegetation was relatively in evenness. 5) From the low percent similarity, the specificity among the stands could be evaluated as considerable. 6) After the index of Morista, the 8th stand in Chang sung showed the generalized vegetation, while the 12th stand in Chang hung showed the specialized vegetation. 7) From the low values of Sneath-Sokal distance, the similarity among the stands investigated appeared very high.

• Korean Journal of Community Nutrition
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• v.21 no.6
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• pp.533-544
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• 2016

Objectives: We aimed to examine levels of physical activity, anthropometric features, and health-related quality of life (HRQoL) among Korean breast cancer survivors who reported changes in their diet after diagnosis. Methods: A total of 380 women who had been diagnosed with stage I to III breast cancer and had breast cancer surgery at least six months before the interview were included. Participants provided information on dietary change after diagnosis, post-diagnostic diet, physical activity, anthropometric measures, and HRQoL through face-to-face interview. We assessed HRQoL levels of breast cancer survivors using a validated Korean version of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and Breast Cancer Module (BR23). We used the logistic regression and generalized linear models to identify the associations of dietary changes in relation with physical activity, anthropometry, and HRQoL. Results: The majority of participants (72.6%) reported that they have changed their diet to a healthier diet after diagnosis. Breast cancer survivors who reported to have change to a healthy diet had higher intakes of vegetables and fruits and lower intakes of red and processed meats, and refined grains than those who did not. Also, survivors with a healthy change in their diet were more likely to engage in physical activity (top vs. bottom tertile: odds ratio [OR], 1.85; 95% confidence interval [95% CI], 1.02-3.36) and have lower body mass index (BMI) (OR, 0.90; 95% CI, 0.82-0.98 for one $kg/m^2$ increment in BMI) compared to those who did not. We found that a healthy change in diet was associated with higher scores of physical functioning (p=0.02) and lower scores of constipation (p=0.04) and diarrhea (p=0.006) compared to those who did not. Conclusions: Healthy changes in diet after breast cancer diagnosis may be associated with lower levels of BMI, and higher levels of physical activity and HRQoL.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.120-127
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• 2012

Exploratory data analysis was carried out by using the long-term wave climate data in Sokcho coastal zone. The main features found in this study are as follows. The coefficient of variations on the wave height and period are about 0.11 and 0.02, respectively. It also shows that the annual components of the wave height and period are dominant and their amplitudes are 0.24 m and 0.56 seconds, respectively. The amount of intra-annual variation range is about two times greater than that of the inter-annual variation range. The distribution shapes of the wave data are very similar to the log-normal and GEV(generalized extreme value) functions. However, the goodness-of-fit tests based on the KS test show as "rejected" for all suggested density functions. Then, the structure of the timeseries wave height data is roughly estimated as AR(3) model. Based on the wave duration results, it is clearly shown that the continuous and maximum duration is decreased as a power function shape and the total duration is exponentially decreased. Meanwhile, the environment of the Sokcho coastal zone is classified as a wave-dominated environment.

• Journal of Distribution Science
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• v.13 no.5
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• pp.53-60
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• 2015

Purpose - The purpose of this paper is to shed light on the importance of the slope and curvature of the volatility curve implied in option prices in the KOSPI 200 options index. A number of studies examine the implied volatility curve, however, these usually focus on cross-sectional characteristics such as the volatility smile. Contrary to previous studies, we focus on time-series characteristics; we investigate correlation dynamics among slope, curvature, and level of the implied volatility curve to capture market information embodied therein. Our study may provide useful implications for investors to utilize current market expectations in managing portfolios dynamically and efficiently. Research design, data, and methodology - For our empirical purpose, we gathered daily KOSPI200 index option prices executed at 2:50 pm in the Korean Exchange distribution market during the period of January 2, 2004 and January 31, 2012. In order to measure slope and curvature of the volatility curve, we use approximated delta distance; the slope is defined as the difference of implied volatilities between 15 delta call options and 15 delta put options; the curvature is defined as the difference between out-of-the-money (OTM) options and at-the-money (ATM) options. We use generalized method of moments (GMM) and the seemingly unrelated regression (SUR) method to verify correlations among level, slope, and curvature of the implied volatility curve with statistical support. Results - We find that slope as well as curvature is positively correlated with volatility level, implying that put option prices increase in a downward market. Further, we find that curvature and slope are positively correlated; however, the relation is weakened at deep moneyness. The results lead us to examine whether slope decreases monotonically as the delta increases, and it is verified with statistical significance that the deeper the moneyness, the lower the slope. It enables us to infer that when volatility surges above a certain level due to any tail risk, investors would rather take long positions in OTM call options, expecting market recovery in the near future. Conclusions - Our results are the evidence of the investor's increasing hedging demand for put options when downside market risks are expected. Adding to this, the slope and curvature of the volatility curve may provide important information regarding the timing of market recovery from a nosedive. For financial product distributors, using the dynamic relation among the three key indicators of the implied volatility curve might be helpful in enhancing profit and gaining trust and loyalty. However, it should be noted that our implications are limited since we do not provide rigorous evidence for the predictability power of volatility curves. Meaning, we need to verify whether the slope and curvature of the volatility curve have statistical significance in predicting the market trough. As one of the verifications, for instance, the performance of trading strategy based on information of slope and curvature could be tested. We reserve this for the future research.