• Journal of Biomedical Engineering Research
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• v.12 no.3
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• pp.203-208
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• 1991

Balancing left/right cardiac output is essential for the automatic control of total artificial hearts(TAH). A fuzzy logic-based control method is presented. We use left atrial pressure( LAP) ann right a'rial pressure( RAP ) as indicators for left/right balancing. The fuzzy controller has four input variables which are measured LAP and RAP and their gradients. Desired variations in left cardiac output(LCO) and right cardiac output(RCO) are cal- culated to keep LAP and RAP within the Physiological limlts. Computer simulations were performed to adjust fuzzy membership functions for variables and verify this control method. Results from simulations showed that LAP and RAP returned to the physiological limits while AoP and PAP stayed within the physiological limits.

• Korean Journal of Child Studies
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• v.24 no.4
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• pp.29-40
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• 2003

Data were collected from 392 4th and 6th grade students by questionnaires and analyzed by Pearson's correlation, ANOVA and multiple regression analysis. More problem behavior was reported by 4th than by 6th graders and by boys than by girls; the gender difference was larger in 4th than 6th graders. Low school satisfaction, authoritative parenting, male gender, and higher age predicted problem behavior. Within group variables that predicted problem behavior were low authoritative parenting, low school satisfaction. Male gender, and low self-control in the 4th graders ; low self-control and school satisfaction in the 6th graders; low authoritative parenting and school satisfaction in girls ; and low school satisfaction, higher age, and low self-control in boys.

• Korean Journal of Child Studies
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• v.36 no.4
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• pp.143-161
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• 2015

This study aims to examine the relationship between mothers' attachment levels, types of verbal control, and infants' language development. The selected participants comprised 224 infants, aged 24-35 months and their mothers (224) at 25 long day care centers located Goyang-si, Gimpo-si in Gyeonggi-do, Incheon and Seoul. The major findings of this study were as follows. First, there were significant differences in mothers' attachment levels, types of verbal control, and infants' language development depending on the mothers' employment status. Secondly, to assess the relative influences of two variables which were significantly associated with infants' language development, the sociodemographic variables of mothers and infants, including infants' age and mothers' employment status, were controlled in order to conduct hierarchical regression analysis. The results revealed that imperative-oriented verbal controls, person-oriented verbal controls, and contact seeking all influenced infants' overall language development.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.8-18
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• 2007

In order to define their relative influence, this study analyzed causal relationships between school adjustment of middle school students and such related variables as locus of control and stress, including clarification of other significant variables affecting school adjustment. Participants were a sample of 331 students from 3 middle schools in Busan. Correlation, analysis of covariance structure modeling, and model-fitness tests were applied to the data. Results indicated that stress on the school, home, social relationships, and self has the more significant influence on the school adjustment, and the locus of control has relatively low influence.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.902-913
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• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. In the previous VSC, the systems must be represented in phase canonical form and the complete measurements for each state variable must be assumed. In order to eliminate these restrictions several VSC methods were proposed. And especially for the systems in phase canonical form with unmeasurable state variables, the reduced order switching function algorithm was proposed. But this method has many drawbacks and can not be used in the case of general form (not phase canonical form) dynamic system. Therefore this paper propose new construction method of switching fuction for the systems in phase canonical form, which reduce the restriction of reduced order switching function algorithm. And this algorithm can be realized for any state representation and adopted in the systems where not all states are available for switching function synthesis or control.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.563-573
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• 2007

Optimal design of an automotive catalytic converter for minimization of cold-start emissions is numerically performed using a micro genetic algorithm for two optimization problems: optimal geometry design of the monolith for various operating conditions and optimal axial catalyst distribution. The optimal design process considered in this study consists of three modules: analysis, optimization, and control. The analysis module is used to evaluate the objective functions with a one-dimensional single channel model and the Romberg integration method. It obtains new design variables from the control module, produces the CO cumulative emissions and the integral value of a catalyst distribution function over the monolith volume, and provides objective function values to the control module. The optimal design variables for minimizing the objective functions are determined by the optimization module using a micro genetic algorithm. The control module manages the optimal design process that mainly takes place in both the analysis and optimization modules.

• Journal of Korean Academy of Medicine & Therapy Science
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• v.10 no.2
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• pp.13-20
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• 2018

Objective: To investigate the effects of a brain fitness exercise on the cognitive function of patients with dementia. Method: Forty-six elderly adults diagnosed with dementia were randomly allocated to the study or control group (n=23 per group). The study and control groups performed a brain fitness and regular exercise, respectively, for 40 minutes a day, three times a week for four weeks. We examined cognitive capacity using MMSE-K, cognitive strength, judgment time, and mental workload scores before and after intervention. Results: The study group showed significant improvements in all variables. In addition, the control group showed a significant improvement in brain stress. We found that there was a significant improvement in the study group when compared with the control group in all variables. Conclusion: Based on these results, we suggest that brain fitness exercise would be effective in improving cognitive functions of dementia patients.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.61-73
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• 2023

As smartphone use is increasing within the middle-aged population, society should pay closer attention to the mental health problems associated with smartphone addiction. This study examines the possibility that depression, anxiety, and ADHD can be interpreted not only as negative aspects, but also as positive aspects, in an addiction-related individual. We used habitual and addictive smartphone behavior as the dependent variables; anxiety, ADHD, depression, and habitual smartphone use as the independent variables; and self-control as a moderating variable. Depression and ADHD in smartphone users were found to be associated with higher levels of addictive smartphone use. Anxiety was having negative effect on addictive smartphone use. However, habitual smartphone use didn't significantly affect addictive smartphone use. Further analysis indicated that depression, anxiety, and ADHD have mediating effects on habitual smartphone use. This study confirmed that psychological factors in adults, as well as habitual/addictive smartphone use and self-control, significantly influence smartphone overdependence.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.884-887
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• 2023

Recently, research has been actively conducted to overcome the limitations of high-priced single sensors and reduce costs through the convergence of low-cost multi-variable sensors. This paper estimates state variables through asynchronous Kalman filters constructed using CVXPY and uses Cvxpylayers to compare and learn state variables estimated from CVXPY with true value data to estimate filter parameters of low-cost sensors fusion.