• Journal of Korea Society of Industrial Information Systems
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• v.7 no.1
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• pp.75-80
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• 2002

We investigate sorry: asymptotic stabilities of the zero solution for the perturbed linear differential system dx/dt=A(t)x+e(t, x)+f(t,x), by using Perron's method and integral inequalities, etc. and we also find some sufficient conditions that ensure some asymptotic stabilities of the zero solution of the system And hence we obtain several results of it.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.367-373
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• 2011

Mechanism of rapid mixing effect on chemical phosphorus removal is evaluated in this study. Assuming that chemical phosphorus removal is unaffected by mixing time, only rapid mixing intensity is evaluated. In order to find out the mechanism, it is hypothesized that rapid mixing affects the Al hydrolysis speciation, and that formation of more monomeric species ($Al^a$) results in better removal of phosphorus. According to a ferron assay, more $Al^a$ formed at higher mixing intensity than at lower intensity. Subsequent experiments revealed that better phosphorus removal was obtained at higher intensity than at lower intensity, in terms of the molar ratio of $Al_{added}/P_{removed}$. The proposed hypothesis was proved in this study. Chemical phosphorus removal is affected by rapid mixing intensity due to its effect on the Al hydrolysis speciation.

• Communications of Mathematical Education
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• v.22 no.4
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• pp.459-469
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• 2008

We give a mathematical approach using Linear Algebra, especially largest eigenvalue and eigenvector on decision making support system. We find a mathematical modeling on decision making problem which could be solved by AHP(Analytic Hierarchy Process) method. Especially, we give a new approach to change evaluation indicator weight on assessing research proposals.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.547-554
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• 2006

The overall objective of this research was to find out the role of rapid mixing conditions in the species of hydrolyzed Al(III) formed by Al(III) coagulants and to evaluate the distribution of hydrolyzed Al(III) species by coagulant dose and coagulation pH. When an Al(III) salt was added to water, monomeric Al(III), polymeric Al(III), precipitate Al(III) was formed by Al(III) hydrolysis. The method of hydrolyzed Al(III) species characterization analysis was based on timed spectrophotometer with ferron as a color developing reagent. The hydrolytic species were divided into monomer, polymer, precipitate from the reaction kinetics. And then, the color intensity for monomeric Al(III) was read 3 min after mixing. With standard Al solution containing monomeric Al(III) only, the Al-ferron color intensity slightly increased with until about 3 min. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) was similar to rapid mixing condition, but for raw water, the species of Al(III) hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. The kinetic constants, Ka and Kb, derived from Al-ferron reaction. The kinetic constants followed very well the defined tendencies for coagulation condition. For pure water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values. Also, for raw water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.331-336
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• 2004

The correlation between polymeric aluminum species of coagulant and its coagulation efficiency was investigated using several commercial polymeric Al(III) inorganic coagulants (Poly Aluminum Hydroxy Chloro Sulfate 2020 (PAHCS2020), Poly Aluminum Hydroxy Chloro Sulfate 2500 (PAHCS2500) which was introduced in Korean water treatment plants. The poly aluminum chloride (PAC), Poly Aluminum Hydroxide Chloride Silicate (PACS)) and the aluminum salts ($AlCl_3$, Alum ($Al_2(SO_4)_3$)) were used for the purpose of comparison. The comparison of the coagulation efficiency of each coagulant was made by turbidity removal through the standard jar testing procedure and the determination of the hydrolytic Al(III) species was made by the ferron method which can differentiate the monomeric aluminum species from the polymeric aluminum species. Overall, PAHCS2020 and PAHCS2500 showed the better performance in turbidity removal than the aluminum salts. The performance of coagulation was even better without adjustment of pH during the coagulation experiment. The positive correlation between polymeric aluminum species of coagulant and coagulation efficiency was found.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.177-186
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• 2022

In this study, newly improved Ferron assay test haved on timed spectrometry was used for the determination of hyolrolytic Al species presented in PACl coagulant. The color development reagent ferron was prepared by using conventional method and two newly developed methods. Then the ferron assay test was used to compare and analyze the distribution of Al(III) hydrolyzed species presented in the prepared PACl and alum. The preparing method of reagent A required an aging period of 7 days by adding a hydroxylamine hydroxide and a 1,10-phenanthroline monohydrate reagent, whereas the preparing method of reagent B was used as a coloring agent immediately without aging time. The regression analysis between UV absorbance and Al concentrations of conventional method and newly developed method of ferron reagents in low-concentration aluminum solutions and high-concentration aluminum solutions, showed the correlation coefficients of 0.999 or higher, as showing high correlations of conventional method and newly developed method. Applying Ferron assay test, Al species in the PACls and alum were classified as Ala(monomeric Al), Alb (polymeric Al), and Alc (colloidal and precipitated Al). Distribution of Al(III) hydrolyzed species according to the preparation of ferron colorimetric reagents was similar.

• Iberoamérica
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• v.13 no.1
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• pp.123-152
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• 2011

The long standing people's culture of Latin America based on social solidarity of the communities makes the political relations between the leader and the people very different from them of the european societies based on the representative democracy. At any rate, the main stream of the Populist Discourses sees the real populist political processes with the pejorative senses attributing the demagogue style of the leaders. In these sense, it is very important to re-consider the populism discourses of Ernesto Laclau who thinks that the populism is a way of interpreting the emergence of the people to establish the social demands in the context of populist real politics. According to Laclau, "the populism seeks for the radical reconfiguration of the revolt of the 'Status Quo' and new order". This work will confirm if this interpretation of Laclau can be applied to Peronist political regime. Meanwhile the first group of the orthodox line of the discourses on populism including Gino Germani shows that the populism is a political movement based on the manipulation and demagogue by the charismatic leader of the irrational mass during the period in transition after the crises of the traditional oligarchy in Latin America. And another line of the main stream of discourses on populism including Cardoso and O'Donnell says that the populism is a political phenomena in a period of transition towards the modernization and the national development by means of the industrialization through the substitution of the imports and the alliance between the classes after the 1930's. But these principal interpretations on populism disregards that in Argentina many urban poor working class people had lived under the racist, unequal painful social relations due to the underestimation and the discrimination by the upper and the middle class with many intellectuals. But Peronism had considered them as the new social subjects with human dignities. And so we have to rethink the clientelism also with another meanings. In this sense, the theories of Ernesto Laclau on populism is very helpful to illuminate the sensitive and ambiguous meanings of Peronism. Especially Peronism makes the urban working class maintain their life styles more tended to them of the traditional communities and go towards the anti-Status Quo. That is a key of success of Peronism not only that time but until these days. And so this study will show that it is the most important thing that Peronist regime had made the emergence of the 'people' in the meaning of advancing the democracy in Argentina.