• Communications for Statistical Applications and Methods
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• v.27 no.3
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• pp.285-299
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• 2020

In many cases, we are interested in identifying independence between variables. For continuous random variables, correlation coefficients are often used to describe the relationship between variables; however, correlation does not imply independence. For finite discrete random variables, we can use the Pearson chi-square test to find independency. For the mixed type of continuous and discrete random variables, we do not have a general type of independent test. In this study, we develop a independence test of a continuous random variable and a discrete random variable without assuming a specific distribution using kernel density estimation. We provide some statistical criteria to test independence under some special settings and apply the proposed independence test to Pima Indian diabetes data. Through simulations, we calculate false positive rates and true positive rates to compare the proposed test and Kolmogorov-Smirnov test.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.6
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• pp.211-218
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• 1983

In this paper, an attempt is made to match the continuous state trajectory of the digital control system with that of its continuous data model. Matching the state trajectories instead of the output responses assures that the performances of the internal variables of the plant as well as the output variables are preserved in the discretization. The mathematical tool used in this research is an extended maximum principle of the Pontryagin type, which enables one to synthesize a staircase type of optimal control signals, such as the output signal of a zero-order hold asociated with a digital controller. A general mathematical expression of the digital controller which may be used to replace the analog controller of a general system while preserving as mauch as possible the performance characteristics of the original continuous-data control system is derived in this paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1629-1636
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• 2004

The continuous casting is primarily a heat-extraction process in which the heat transfer at various cooling zones profoundly influences quality of products. So development of numerical model is necessarily needed for more specific and clear investigations upon heat transfer mechanism at mold and secondary cooling zones. In this study, heat transfer coefficients which show the characteristic of heat transfer mechanism in mold are calculated for more exact analysis with temperature measured in bloom mold using optimal algorithm, and finally the validity of cooling conditions at secondary cooling zone actually used at field fur 30 Ton bloom type continuous casting of 0.187%C is investigated. From the results of solidification analysis, the characteristic of bloom mold shows a similar tendency with that of previous studies, and optimized cooling conditions for 0.187%C are presented.

• Journal of applied mathematics & informatics
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• v.37 no.3_4
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• pp.245-249
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• 2019

In this paper we obtain characterizations of a family of continuous probability distribution by independence property of upper record values. Also, we introduce some examples of the characterizations of distributions from these general classes of continuous distributions.

• The Korean Journal of Applied Statistics
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• v.32 no.3
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• pp.375-389
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• 2019

Sample attrition according to a long-term tracking reduces the representativeness of the sample data in a panel study. Most panel surveys in South Korea and other countries have prepared response adjustment weights in order to solve problems regarding representativeness due to sample attrition. In this paper, we divided the panel data into continuous response group and non-continuous response group according to response patterns and considered a weighting adjustment method to reduce the bias of the non-continuous response group. A simulation indicated that the proposed composite estimation type weighting method, which reflected the characteristics of non-continuous response groups, could be more efficient than other weighting methods in terms of reducing non-response bias. As a case study, the proposed methods are applied to the Korean Longitudinal Study of Ageing (KLoSA) data of the Korea Employment Information Service.

• Textile Coloration and Finishing
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• v.12 no.1
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• pp.68-75
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• 2000

In this study, polyester DTY faille(yoryu) and N/NP microfiber fabrics were pretreated (desizing, scouring and shrinking) by Continuous Scouring and Shringking Equipment with rota-drum and conveyor type in which types were different with retaining method. The results were as follows. The shrinkage ratio of wp/wf direction of DTY fabrics scoured by conveyor type was 1.5/23% higher than those by rota-drum type at $97^\circ{C}$ with 10min. treatment. In this case, The shrinkage ratio of wp/wf direction by those types was about 15/27%, respectively. The shrinkage ratio of wp/wf direction of N/NP microfiber fabrics scoured by conveyor type was 1.5/23% higher than that by rota-drum type at $97^\circ{C}$ with 10min. treatment. The size add-on of DTY fabrics scoured at $97^\circ{C}$ with 10min. treatment by conveyor type and by rota-drum type were 0.15% and 0.42%, respectively. The size add-on of DTY fabric treated by rota-drum type decreased until 9min. of treated time, but increased after 9min. The size add-on of N/NP microfiber fabrics treated by conveyor type was decreased by increasing temperature and treated time, while the size add-on of that treated by rota-drum type was decreased until 6min. treated time and increased after 6min. The size add-on of N/NP microfiber fabrics treated by conveyor type at $97^\circ{C}$ for 10min. was 0.3% lower than that by rota-drum type.

• Honam Mathematical Journal
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• v.42 no.2
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• pp.251-268
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• 2020

In this paper, we estimate the degree of approximation by means of the complete modulus of continuity, the partial modulus of continuity, the Lipschitz-type class and Petree's K-functional for the bivariate Szász-Kantorovich operators based on Brenke-type polynomials. Later, we construct Generalized Boolean Sum operators associated with combinations of the Szász-Kantorovich operators based on Brenke-type polynomials. In addition, we obtain the rate of convergence for the GBS operators with the help of the mixed modulus of continuity and the Lipschitz class of the Bögel continuous functions.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.426-429
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• 1996

Complex regional pain syndrome Type II(CRPS) can be diagnosed by new IASP criteria in 1994. Sympathetically maintained pain may or may not be present in a patient with complex regional pain syndrome. We experienced a CRPS Type II patient who has sympathetically maintained pain as a major painful nature developed after right multiple iliac bone fracture, right femoral artery thrombosis and lumbosacral plexus injury. Combination treatment with L2, L3, L4 sympathetic ganglion block and continuous lower thoracic epidural block for 30 days were tried to get long term effect. The patient had signs of successful. sympathetic denervation of the right foot. After that pain relief was sustained until three month later.

• Korean Journal of Mathematics
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• v.24 no.4
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• pp.647-662
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• 2016

In this paper, we study Lipschitz continuous, the boundedness and compactness of the composition operator $C_{\phi}$ acting between the general hyperbolic Bloch type-classes ${\mathcal{B}}^{\ast}_{p,{\log},{\alpha}}$ and general hyperbolic Besov-type classes $F^{\ast}_{p,{\log}}(p,q,s)$. Moreover, these classes are shown to be complete metric spaces with respect to the corresponding metrics.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.847-852
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• 2003

It was examined carefully that the bacterial die-off between Chlorella vulgaris and E. coli. W3110 was tested through adding TOC (total organic carbon) with the lab-scaled continuous river water flow system (CRWFS). Artificial synthetic wastewater was applied at two levels of organic carbon concentration; 1,335 mg/l in treatment type 1 and 267 mg/l in type 2. In both types, the population densities of Chlorella vulgaris were similar in a maximum 8.25 ${\times}$ 10$\^$6/ cells/ml (type 1) and 6.925 ${\times}$ 10$\^$6/ cells/ml (type 2). The maximum densities of E. coli. W3110 were 2.0 ${\times}$ 10$\^$8/ colony forming unit (CFU)/ml in type 1 and 3.9 ${\times}$ 10$\^$8/ CFU/ml in type 2. The densities increased for 11 days in type 1 and 4 days in type 2, then decreased rapidly till the 35th day, then slightly increased again. This trend was prominent in type 2. It implied that a wider range of nutrients was required in the growth of heterotrophic bacteria in type 2 than in type 1. We could not expect successful bacterial die-off if the wastewater retention time was not furnished sufficiently.