• The Journal of Information Technology
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• v.6 no.1
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• pp.1-10
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• 2003

In this paper, a public key exponential encryption algorithm for data security of computer network is proposed. This is based on the security to a difficulty of polynomial factorization. For the proposed public key exponential encryption, the public key generation algorithm selects two polynomials f(x,y,z) and g(x,y,z). The enciphering first selects plaintext polynomial W(x,y,z) and multiplies the public key polynomials, then the ciphertext is computed. In the proposed exponential encryption system of public key polynomial, an encryption is built by exponential encryption multiplied thrice by the optional integer number and again plus two public polynomials f(x,y,z) and g(x,y,z). This is an encryption system to enforce the security of encryption with help of prime factor added on RSA public key. The propriety of the proposed public key exponential cryptosystem algorithm is verified with the computer simulation.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.225-227
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• 2009

본 논문에서는 전압형 3상 ZSI(Z-source Inverter)의 입력전압과 커패시터 충전전압을 검출하고 ZSI의 기본 정의를 이용해 지령전압에 대한 변조지수(Modulation Index)를 결정하는 방법과 출력전압 제어가 가능한 변형된 SVM(공간벡터 변조방식)으로 구성된 알고리즘을 소개한다. 제안된 알고리즘은 ZSI의 이득과 변조지수의 정의를 이용한 간단한 방법으로 변조지수를 변화시켜 출력전압을 일정하게 유지하는 방법이다. PSIM을 통하여 타당성을 입증하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.47-60
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• 1975

For the calculation of population parameter and estimation of recruitment of a fish population, an application of multiple regression method was used with some statistical inferences. Then, the differences between the calculated values and the true parameters were discussed. In addition, this method criticized by applying it to the statistical data of a population of bigeye tuna, Thunnus obesus of the Indian Ocean. The method was also applied to the available data of a population of Pacific saury, Cololabis saira, to estimate its recuitments. A stock at t year and t+1 year is, $N_{0,\;t+1}=N_{0,\;t}(1-m_t)-C_t+R_{t+1}$ where $N_0$ is the initial number of fish in a given year; C, number o: fish caught; R, number of recruitment; and M, rate of natural mortality. The foregoing equation is $$\phi_{t+1}=\frac{(1-\varrho^{-z}{t+1})Z_t}{(1-\varrho^{-z}t)Z_{t+1}}-\frac{1-\varrho^{-z}t+1}{Z_{t+1}}\phi_t-a'\frac{1-\varrho^{-z}t+1}{Z_{t+1}}C_t+a'\frac{1-\varrho^{-z}t+1}{Z_{t+1}}R_{t+1}......(1)$$ where $\phi$ is CPUE; a', CPUE $(\phi)$ to average stock $(\bar{N})$ in number; Z, total mortality coefficient; and M, natural mortality coefficient. In the equation (1) , the term $(1-\varrho^{-z}t+1)/Z_{t+1}$s almost constant to the variation of effort (X) there fore coefficients $\phi$ and $C_t$, can be calculated, when R is a constant, by applying the method of multiple regression, where $\phi_{t+1}$ is a dependent variable; $\phi_t$ and $C_t$ are independent variables. The values of Mand a' are calculated from the coefficients of $\phi_t$ and $C_t$; and total mortality coefficient (Z), where Z is a'X+M. By substituting M, a', $Z_t$, and $Z_{t+1}$ to the equation (1) recruitment $(R_{t+1})$ can be calculated. In this precess $\phi$ can be substituted by index of stock in number (N'). This operational procedures of the method of multiple regression can be applicable to the data which satisfy the above assumptions, even though the data were collected from any chosen year with similar recruitments, though it were not collected from the consecutive years. Under the condition of varying effort the data with such variation can be treated effectively by this method. The calculated values of M and a' include some deviation from the population parameters. Therefore, the estimated recruitment (R) is a relative value instead of all absolute one. This method of multiple regression is also applicable to the stock density and yield in weight instead of in number. For the data of the bigeye tuna of the Indian Ocean, the values of estimated recruitment (R) calculated from the parameter which is obtained by the present multiple regression method is proportional with an identical fluctuation pattern to the values of those derived from the parameters M and a', which were calculated by Suda (1970) for the same data. Estimated recruitments of Pacific saury of the eastern coast of Korea were calculated by the present multiple regression method. Not only spring recruitment $(1965\~1974)$ but also fall recruitment $(1964\~1973)$ was found to fluctuate in accordance with the fluctuations of stock densities (CPUE) of the same spring and fall, respectively.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.555-563
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• 2016

The morphological characteristics and genetic relationships among 32 germplasms of Zanthoxylum schinifolium and Zanthoxylum piperitum collected from two farms in Korea were investigated. The traits with the most variability were seed color, leaf size, and spine size. The intraspecific polymorphism of Z. schinifolium and Z. piperitum was 96.5% and 60.3%, respectively. The genetic diversity and Shannon’s information index values ranged from 0.11 to 0.33 and 0.19 to 0.50, with average values of 0.26 and 0.42, respectively. Two ISSR primers (UBC861 and UBC862) were able to distinguish the different species. The genetic similarity matrix (GSM) revealed variability among the accessions ranging from 0.116 to 0.816. The intraspecific GSM for Z. schinifolium and Z. piperitum was 0.177-0.780 and 0.250-0.816, respectively. The GSM findings indicate that Z. schinifolium and Z. piperitum accessions have high genetic diversity and possess germplasms qualifying as good genetic resources for cross breeding. The clustering analysis separated Z. schinifolium and Z. piperitum into independent groups, and all accessions could be classified into three categories. Z. Schinifolium var. nermis belonged to independent groups. Comparison of the clusters based on morphological analysis with those based on ISSR data resulted in an unclear pattern of division among the accessions. The study findings indicate that Z. schinifolium and Z. piperitum accessions have genetic diversity, and ISSR markers were useful for identifying Z. schinifolium and Z. piperitum.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.460-460
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• 2011

국내에서는 수자원 정보화 사업에 일환으로 국가수자원종합정보시스템(WAMIS)을 개발하여 수자원에 관련된 많은 기초 자료 정보를 일반에 공개 제공하고 있으나, 주 이용 계층은 수자원관련 종사자 또는 연구자들이 대부분이다. 국가수자원종합정보시스템에서 제공하는 양질의 수자원 정보를 일반 국민들이 보다 쉽게 이해하고, 이용할 수 있도록 국내에서는 이들 기초자료를 바탕으로 다양한 수자원 지표 및 지수를 개발하였다. 이러한 수자원 관련 지표 및 지수를 개발하기 위해서는 서로 다른 단위와 특성을 가진 자료들을 모아 하나의 지표로 정의하는 과정이 필요하며, 하나의 지표로 정의되기 위해서는 반드시 표준화(normalization)과정이 필요하다. 국내에서 가장 보편적으로 사용하고 있는 방법은 Z-score법이며, 이외에도 가장 단순하고 간단한 방법인 Ranking 법, 자료의 극값(최대값, 최소값)을 이용하는 Re-scaling법, 일정 지표를 기준으로 하는 Distance to a reference country법 등이 있다. 표준화 방법은 각기 다른 장 단점을 가지고 있으며, 그 특성에 따라 정의되는 지표값은 다르게 나타날 수 있기에 지수값의 변화를 야기시킬 수 있다. 본 연구에서는 기 개발된 물이용안전성지수를 이용하여 기존 분석과 다양한 표준화 방법을 이용하여 지표를 산정하였을 때 표준화 방법에 따른 변화를 분석해 보고자 한다. 기존 연구에서 사용된 표준화 방법은 Z-score법이며, 다른 표준화 방법을 적용해 봄으로서 기존 산정 결과와의 차이를 비교 분석하였다. 지수를 구성하는 세부지표에 따라 수집되는 기초자료의 단위 및 특성은 다양하기 때문에 적합한 표준화 방법을 찾는 과정은 매우 중요하며, 이는 지표를 보다 정확하게 산정할 수 있도록 한다. 합리적인 표준화 방법을 통해 올바른 지수를 도출할 수 있고 객관적으로 수자원 환경을 평가할 수 있으며, 또한 수자원 계획 및 정책 개발에 있어 중요한 기준으로서 적용 할 수 있을 것으로 기대된다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.339-340
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• 2010

본 논문에서는 Z-네트워크 커패시터 전압 제어를 위한 변조지수 적분제어를 이용하여 3상 Z-소스 인버터(ZSI)의 출력 교류전압을 일정하게 제어하는 방법을 제안하였다. ZSI의 직류전압 및 부하가 변동되는 상황에서도 제안된 방법을 사용하여 일정한 출력 교류전압을 유지하는 것이 가능하다. 제안된 방법의 타당성을 입증하기 위해 ZSI의 직류전압이 200[V]에서 150[V]로 급감 하는 경우와 부하가 $60[{\Omega}]$에서 $20[{\Omega}]$으로 급감하는 경우를 PSIM 시뮬레이션을 이용해 검증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.735-742
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• 2019

Drought is a social phenomenon in which the degree of perception varies depending on the affected factors, and is defined as various relative concepts such as meteorological drought, hydrological drought, agricultural drought, and climatological drought. In this study, a comparative analysis of meteorological drought among variously defined droughts was conducted and the applicability of the drought index was examined by comparing the actual drought cases and the results of meteorological drought index analysis. In order to compare the drought index, we used standardized Precipitation Index (SPI), China-Z Index (CZI), Modified CZI (MCZI) and Z-Score Index Respectively. Four drought indices were used for the Taebaek and Sokcho areas. The drought index was analyzed using the meteorological data from 1986 to 2015 for a duration of 3 months. As a result of the analysis, the SPI drought index was analyzed to be highly reproducible for the case of drought with past limited water series. In the case of CZI and MCZI drought indices, the number of extreme dry occurrences is similar to that of the past cases, but the reproducibility is low for the actual drought years. In the case of ZSI drought index, it is analyzed that the number of occurrences and the comparison with the past cases are inferior in reproducibility. For the meteorological drought index using precipitation, it would be effective to use the SPI drought index with the highest reproducibility and the past drought case.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.363-364
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• 2010

본 논문에서는 전압형 3상 Z-소스 인버터의 전압 안정화를 위한 새로운 제어방법을 제안하였다. 제안된 방법은 전압형 3상 Z-소스 인버터의 입력전압과 Z-임피던스 망의 커패시터 인가전압을 검출하여 제어하는 방식이다. 검출된 두 전압을 이용해 동작중인 시스템의 전압이득 및 변조지수를 유도하였다. 제안된방법은 전압 안정화를 위한 전압이득 및 변조지수와의 비교연산을 통해 출력전압을 안정화 시키는 방법으로 PISM을 이용하여 출력 교류 파형 및 제어방법을 분석하였다.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1208-1221
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• 2020

The purpose of this study was to provide basic data for predicting the sports consumption market that Generation Z will lead by applying data mining based decision tree analysis to explore Generation Z sports consumption style. Therefore, the survey was conducted by selecting males and females aged 19 or older as a sample among Generation Z, and data of 429 people were used for the final analysis. For data processing, frequency analysis, exploratory factor analysis, retest and reliability analysis, and decision tree analysis were performed using the SPSS statistics (ver. 21.0) program. The main results of this study are as follows. First, if the rational efficiency index is high and the aesthetic consumption index is low, the probability of being classified as a group of female was 96.8%. On the other hand, if the rational efficiency and perception of price index were low, the probability of being classified as a male group was 100%. Second, if the brand orientation, perception of price, and rational efficiency index were high, the probability of being classified as a capital area group was 97.3%. Contrary to the results presented above, the probability of being classified as a other area group was 82.1% when the brand orientation, commemoration rites, and status symbol index were low. Third, the status symbol and trend oriented index were high, and if the functionality index was low, the probability of being classified into daily life and fashion groups was 77.6%. On the contrary, if the status symbol index is low, the retention of membership and enjoy consumption index is high, the probability of being classified into exercise and competition groups was 81.0%.

• The Journal of Information Technology
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• v.6 no.4
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• pp.59-68
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• 2003

In this paper, a public key kanpsack cryptosystem algorithm is based on the security to a difficulty of polynomial factorization in computer communication is proposed. For the proposed public key kanpsack cryptosystem, a polynomial vector B(x,y,z) is formed by transform of superincreasing vector A, a polynomial f(x,y,z) is selected. Next then, the two polynomials B(x,y,z) and f(x,y,z) is decided on the public key. Therefore a public key knapsack cryptosystem is based on the security to a difficulty of factorization of a polynomial f(x,y,z)=0 with three variables. In this paper, a public key encryption algorithm for data security of computer network is proposed. This is based on the security to a difficulty of factorization. For the proposed public key encryption, the public key generation algorithm selects two polynomials f(x,y,z) and g(x,y,z). The propriety of the proposed public key cryptosystem algorithm is verified with the computer simulation.