• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1215-1219
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• 2008

We find a necessary and sufficient condition that the prime factors of $A^m+1$ and $A^n+1$ coincide for odd positive integers $n>m{\geq}1$. Moreover, we also find a necessary and sufficient condition that the set of all prime factors of $A^m+1$ is a subset of those of $A^n+1$ for $n>m{\geq}1$.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.172-177
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• 2012

In areas around Deoksan Li and Deokjeon Li, Inje Eup, Inje Gun, located between $38^{\circ}2^{\prime}55^{{\prime}{\prime}}N$ and $38^{\circ}5^{\prime}50^{{\prime}{\prime}}N$ in latitude and $128^{\circ}11^{\prime}20^{{\prime}{\prime}}E$ and $128^{\circ}18^{\prime}20^{{\prime}{\prime}}E$ in longitude, large-sized avalanche disasters occurred due to Typhoon Ewiniar in 2006. As a result, 29 people were dead or missing, along with a total of 37.25 billion won of financial loss(Gangwon Province, 2006). To evaluate such landslide and debris flow risk areas and their vulnerability, this study applied a technique called 'Weight of Evidence' based on GIS. Especially based on the overlay analysis of aerial images before the occurrence of landslides and debris flows in 2005 and after 2006, this study extracted 475 damage-occurrence areas in a shape of point, and established a DB by using such factors as topography, hydrologic, soil and forest physiognomy through GIS. For the prediction diagram of debris flow and landslide risk areas, this study calculated W+ and W-, the weighted values of each factor of Weight Evidence, while overlaying the weighted values of factors. Besides, the diagram showed about 76% in prediction accuracy, and it was also found to have a relatively high correlationship with the areas where such natural disasters actually occurred.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.62-74
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• 2021

We compare Over-the-Tops (OTTs), Netflix and Amazon Prime Video (APV) with five success factors of innovation. Firstly, Netflix offers better personalized service than APV, because APV has collaborative filtering algorithms to recommend safe bets, not the customers really want. Secondly, APV' user interface is undercooked to lock the members in, even if it has more content and better price offer than Netflix retaining its loyal customers despite the price increase. Thirdly, Netflix has simple subscription model with three tiering, but APV has complicated pricing model having annual and monthly, APV and Prime Video (AV) app, Amazon subscription and extra payment of Amazon Prime Channels (APCs). Fourthly, Amazon has fewer partnership than Netflix especially when it comes to local TV series. Instead, Amazon has live TV channel collaboration including sports content. Lastly, both have strategic and operational agility in their organization well.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.155-156
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• 2021

Most of the construction works in domestic are not direct undertaking work, but by a contract method including subcontracting. Therefore, a general contractor for each project jointly carry out construction work with a specialty contractor for each engineering type. However, in terms of contract, this method is not a joint venture contract, but a subcontract. Accordingly, this system can cause various problems between the prime contractor and the subcontractor. Therefore, this study aims to extract and present the actual obstacle factors in terms of specialty contract company performing specialty construction work for construction project. The presented contents are expected to present the standard for the cooperation system that the prime contractor and the subcontractor can win-win.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.4
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• pp.50-60
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• 1996

The purpose of this study is to investigate the prime factors that affect user satisfaction of area and facilities in urban forests, to classify those factors, to find out factorial structure of user satisfaction about them, and then to suggest important indicators in the urban forest planning, design, and development. The survey research was done using the self-administered questionnaire method by the people in the city of the Pusan who participated in recreational activities in the Mt. Keumjung. Factor analysis was used to extract the prime factors related to the recreational satisfaction concerning the area and facilities of the urban forest by the SPSS program, and then prime factors were used to investigate the factorial structure of user recreational satisfaction in the urban forest by the LInear Structure RELation program. According to the factor analysis concerning the 13 variables, 4 prime factors by the statistical values were considered as effective, indicating, 'health and recreational facilities', 'convenience and management facilities','facilities for the physical and psychological training' and 'historical and cultural areas'. The results of the causal structure analysis were identified as having significant effects mutually on endogenous variables, 'overall recreational satisfaction of the areas and facilities in the Mt. Keumjung','health and recreational facilities','convenience and management facilities','facilities for the psychological training', and 'historical and cultural areas'. But exogenous variables which have significant effects on endogenous variables were also indentified. Overall fits of both causal model were very good. The hypothetical causal structural equation models based on the results found partially significant correlation between dndogenous variables and between envogenous and exogenous variables. These significant relationships indiate important factors and variables that should be considered in planning, design, and development of the urban forests. Therefore, development direction of the Mt. Keumjung has to be analyzed as significant factors concerning user recreational satisfaction in a systematic was, recognized as important variables for planning process. The plan for development and management also should reflect the natural conservation policy from the environmental conservation movement like natural conservation advertisement and environmental education.

• Bulletin of the Korean Mathematical Society
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• v.55 no.6
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• pp.1659-1666
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• 2018

Let $P_r$ denote an almost-prime with at most r prime factors, counted according to multiplicity. In this paper, it is proved that for every sufficiently large even integer N, the equation $$N=x^2+p_1^2+p_2^3+p_3^3+p_4^4+p_5^4$$ is solvable with x being an almost-prime $P_4$ and the other variables primes. This result constitutes an improvement upon that of $L{\ddot{u}}$ [7].

• East Asian mathematical journal
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• v.19 no.1
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• pp.81-89
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• 2003

There are many algorithms for factoring integers. The trial division algorithm is one of the most efficient algorithms for factoring small integers(say less than 10,000,000,000). For a number n to be factored, the runtime of the trial division algorithm depends mainly on the size of a nontrivial factor of n. In this paper, we create a function named factors that can implement the trial division algorithm in ActionScript and using the factors function we construct an interactive Prime Factorization Movie and an interactive GCD Movie.

• School Mathematics
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• v.12 no.3
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• pp.371-388
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• 2010

The goals of this study are to inquire middle school students' understanding about prime number and to propose pedagogical implications for school mathematics. Written questionnaire were given to 198 Korean seventh graders who had just finished learning about prime number and prime factorization and then 20 students participated in individual interviews for member checks. In defining prime and composite numbers, the students focused on distinguishing one from another by numbering of factors of agiven natural number. However, they hardly recognize the mathematical connection between prime and composite numbers related on the multiplicative structure of natural number. This study suggests that it is needed to emphasize the conceptual relationship between divisibility and prime decomposition and the prime numbers as the multiplicative building blocks of natural numbers based on the Fundamental Theorem of Arithmetic.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.328-332
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• 2018

Soybean [Glycine max (L.) Merr.] seed is an important dietary source of protein, oil, carbohydrate, isoflavone and other various nutrients for humans and animals. However, there are anti-nutritional factors in the raw mature soybeans. Kunitz trypsin inhibitor (KTI) protein and stachyose are the main anti-nutritional factors in soybean seed. The ${\alpha}^{\prime}$-subunit of ${\beta}$-conglycinin protein exhibit poor nutritional and food processing properties. The genetic removal of the KTI and ${\alpha}^{\prime}$-subunit proteins will improve the nutritional value of the soybean seed. The objective of this research was to develop a new soybean strain with KTI and ${\alpha}^{\prime}$-subunit protein free ($titicgy_1cgy_1$ genotype) and proper agronomic traits. A breeding population was developed from the cross of the Bl-1 and 15G1 parents. A total of 168 $F_2$ seeds from the cross of the BL-1 and 15G1 parents were obtained. The segregation ratios of 9: 3: 3: 1 ($104Ti\_Cgy_{1\_}:\;30Ti\_cgy_1cgy_1:\;21cgy_1cgy_1Ti\_:\;13titicgy_1cgy_1$) between the Ti and $Cgy_1$ genes in the $F_2$ seeds were observed (${\chi}^2=5.12$, P=0.5-0.10). Two $F_4$ plant strains with proper agronomical traits and $titicgy_1cgy_1$ genotype (free of both KTI and ${\alpha}^{\prime}$-subunit protein) were selected and harvested. 2 strains (S1 and S2) had yellow seed coats and hilum. The plant height of the S1 strain was 65 centimeters. The 100-seed weight was 29.2 g. The plant height of the S2 strain was 66 centimeters and 100-seed weight was 26.2 g. The two strains selected in this research will be used to improve the new cultivar that will be free of the KTI and ${\alpha}^{\prime}$-subunit proteins.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.4
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• pp.1-8
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• 1968

A TANT network is a three-level network composed solely of NAND gates having only true(i.e. uncomplemented) inputs. The paper presents a technique for finding for any given Boolean function a least-cost TANT network. The first step of the technique is to determine essential prime implicants(EPI) by Quine-McCluskey procedure or other methods and generate prime implicants(PI) hving the same head as any one of EPI by consensus operation. The second step is to select common factors among the usable tail factors. The selcetion phase is analogous to the use of C-C table. The last step is to minimize inputs by deleting the redundant PI. the technique permits hand solution of typical five-and six-variable problems.