• Journal of Families and Better Life
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• v.22 no.4
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• pp.157-171
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• 2004

In this study, adolescent consumers were first classified by their consumption propensity, and different types of adolescent consumers were compared regarding their consumption behavior and allowance management. The adolescents were classified into four groups by type of control and symbol-orientation. The adolescents of the external control group possessed more commodities than the internal control group. There were significant differences in the patterns of allowance management in the four groups. The low-external symbol group owned more commodities than high-external symbol group. The high-external symbol group considered external appearance more important when purchasing commodities.

• Journal of Biomedical Engineering Research
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• v.26 no.6
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• pp.357-363
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• 2005

Active contour models have been extensively used to segment, match, and track objects of interest in computer vision and image processing applications, particularly to locate object boundaries. With conventional methods an object boundary can be extracted by controlling the internal energy and external energy based on energy minimization. However, this still leaves a number of problems, such as initialization and poor convergence in concave regions. In particular, a contour is unable to enter a concave region based on the stretching and bending characteristic of the internal energy. Therefore, this study proposes a method that controls the internal energy by moving the local perpendicular bisector point of each control point on the contour, and determines the object boundary by minimizing the energy relative to the external energy. Convergence at a concave region can then be effectively implemented as regards the feature of interest using the internal energy, plus several objects can be detected using a multi-detection method based on the initial contour. The proposed method is compared with other conventional methods through objective validation and subjective consideration. As a result, it is anticipated that the proposed method can be efficiently applied to the detection of the pulmonary parenchyma region in medical images.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.515-525
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• 2008

In this paper, the problem of delay-dependent stabilization for singular systems with multiple internal and external incommensurate constant point delays is investigated. The condition when a singular system subject to point delays is regular independent of time delays is given and it can be easily test with numerical or algebraic methods. Based on Lyapunov-Krasovskii functional approach and the descriptor integral-inequality lemma, a sufficient condition for delay-dependent stability is obtained. The main idea is to design multiple memoryless state feedback control laws such that the resulting closed-loop system is regular independent of time delays, impulse free, and asymptotically stable via solving a strict linear matrix inequality (LMI) problem. An explicit expression for the desired memoryless state feedback control laws is also given. Finally, a numerical example illustrates the effectiveness and the availability for the proposed method.

• Communications of Mathematical Education
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• v.34 no.3
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• pp.325-354
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• 2020

This study utilized longitudinal data from the 2013 year (Secondary Middle School) to 2017 year (Secondary High School) of the Seoul Education Termination Study. Using the latent growth model and the piecewise growth model, we investigated the changes in mathematics academic achievement, internal factors(self-concept, self-control, self-assessment of life satisfaction), and external factors(school climate, guardians) as students' grades increased, and examined whether internal factors and external factors influence the changes in mathematics academic achievement. We examined whether internal and external factors influence the change in academic achievement. As a result of analysis, it was found that mathematics academic achievement remained unchanged from the first grade of middle school to the second grade of middle school, and steadily increased from the second grade of middle school to the first grade of high school, and then decreased slightly in the second grade of high school. The internal and external factors had little change. It has been found that self-concept, self-control as internal factors, and school climate as external factors influence changes in mathematics academic achievement.

• Korean Journal of Child Studies
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• v.23 no.3
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• pp.1-15
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• 2002

The subjects of this study were 4th to 6th grade children and instruments were the Teenage Inventory of Social Skills, the Internal-External Control Scale, the Self-Esteem Scale, and the Peer Relations Questionnaire. In the concurrent study, children lower in social skills and in self-esteem and external in locus of control reported more bullying and victimization. Children higher in social skills and in self-esteem and internal in locus of control reported more prosocial behavior. In the prospective study, children lower in social skills were more involved in bullying and victimization. Children higher in social skills reported more prosocial behavior. The effects of locus of control and self-esteem on peer relations diminished over time. However, social skills had a significant influence on bullying, victimization and prosocial behavior up to two years later. Children lower in psychosocial development were more vulnerable to peer victimization.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.185-193
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• 2011

The successful and sustainable growth of SMEs depends on their ability of strengthen their competitiveness in quality and cost and service more than anything else as a fundamental of operation. Among these key competitive factors of SMEs, quality is the most critical factor in manufacturing business fields. There are many different ways to improve the quality performance but it needs proper management decision to choose the best way what can maximize outputs with minimum inputs. And it needs effective measurement methods and some indicators to analysis the quality performance properly. The quality cost is one of the simplest key indicators to measure the quality performance and the effectiveness of quality related management decisions. In this study, through survey on local SMEs, we found that their average annual quality cost ratio versus turnover - total amount of annual quality cost divided by annual turnover - is around 3.69% excluded some SME's performances what have different quality control measures with others. And we found some results what corresponded with the early studies on the correlations between those categorized quality costs factors and some discrepancies between some of the literature model and the early case study results as follows. There were negative correlations between the Prevention costs and the External failure costs, and the Appraisal costs and the External failure costs, and there was positive correlation between the Appraisal costs and Internal failure costs same as early studies. But, we couldn't found any strong negative correlations between the Cost of control - Prevention costs & Appraisal costs - and the Cost of Failure of control - Internal & External failure costs -.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.183-188
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• 2014

Solenoid operated electromagnetic control valve (ECV) using in an external variable displacement swash plate type compressor is widely used for air conditioning control system because of its low energy consumption and high efficient characteristics. ECV controls the entire vehicle air conditioning system by means of a pulse width modulation (PWM) system that supplied from an external controller. Different pressure ports located within ECV has important functions to control the air/refrigerant flow through its internal passages. The flow paths are preciously maintained with acceptable ranges of leakage (gap) between the parts inside it which is followed by effective design and critical dimensioning of its internal features. Therefore, it saves energy losses from the solenoid operation as well as ensures the balance of forces within it. The research paper highlights analysis of the leakages (at different pressure ports) and dimensioning tolerance factors that affects the ECV performance.

• Smart Structures and Systems
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• v.26 no.5
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• pp.575-589
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• 2020

For vibration control of stay cables in cable-stayed bridges, viscous dampers are frequently used, and they are regularly installed between the cable and the bridge deck. In practice, neoprene rubber bushings (or of other types) are also widely installed inside the cable guide pipe, mainly for reducing the bending stresses of the cable near its anchorages. Therefore, it is important to understand the effect of the bushings on the performance of the external damper. Besides, for long cables, external dampers installed at a single position near a cable end can no longer provide enough damping due to the sag effect and the limited installation distance. It is thus of interest to improve cable damping by additionally installing dampers inside the guide pipe. This paper hence studies the combined effects of an external damper and an internal damper (which can also model the bushings) on a stay cable. The internal damper is assumed to be a High Damping Rubber (HDR) damper, and the external damper is considered to be a viscous damper with intrinsic stiffness, and the cable sag is also considered. Both the cases when the two dampers are installed close to one cable end and respectively close to the two cable ends are studied. Asymptotic design formulas are derived for both cases considering that the dampers are close to the cable ends. It is shown that when the two dampers are placed close to different cable ends, their combined damping effects are approximately the sum of their separate contributions, regardless of small cable sag and damper intrinsic stiffness. When the two dampers are installed close to the same end, maximum damping that can be achieved by the external damper is generally degraded, regardless of properties of the HDR damper. Field tests on an existing cable-stayed bridge have further validated the influence of the internal damper on the performance of the external damper. The results suggest that the HDR is optimally placed in the guide pipe of the cable-pylon anchorage when installing viscous dampers at one position is insufficient. When an HDR damper or the bushing has to be installed near the external damper, their combined damping effects need to be evaluated using the presented methods.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.34-44
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• 1998

Living organisms are influenced by many external rhythms and they have adapted their physiology to periodically changing conditions. These adaptive strategies are controlled by endogenous innate programs of behavior and physiology which are determined by external signals ("Zeitgeber"). There are many biological rhythms, each with its own characteristic functional adaptation. Among them, the presence of endogenous time control of feeding and drinking becomes obvious. There are increasing evidences that the control of food intake, food selection, and drinking are regulated by the endogenous rhythms including a circadian rhythm. However, there have been many restrictions in understanding the endogenous control of food intake itself and its mechanism. To broaden our know ledges of the endogenous time control of feeding and drinking, the author reviwed the characteristics of the endogenous timing for food intake, the influence of circadian pacemakers and food-entrainable oscillators, the interaction between the circadian control and the external and internal conditions in the control of food intake, the conseqences of feeding, the circadian control of food selection, and the biological cycles in energy balance.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.2
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• pp.43-47
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• 2022

Purpose Radioimmunoassay implement quality control by systematizing the internal quality control system for quality assurance of test results. This study aims to contribute to the quality assurance of radioimmunoassay results and to implement systematic quality control by measuring the average CV of internal quality control and external quality control by plenty of institutions for reference when setting the laboratory's own acceptable range. Materials and Methods We measured the average CV of internal quality control and the bounce rate of more than 10.0% for a total of 42 items from October 2020 to December 2021. According to the CV result, we classified and compared the upper group (5.0% or less), the middle group (5.0~10.0%) and the lower group (10.0% or more). The bounce rate of 10.0% or more was compared by classifying the item of five or more institutions into tumor markers, thyroid hormones and other hormones. The average CV was measured by the overall average and standard deviation of the external quality control results for 28 items from the first quarter to the fourth quarter of 2021. In addition, the average CV was measured by the overall average and standard deviation of the proficiency results between institutions for 13 items in the first half and the second half of 2021. The average CV of internal quality control and external quality control was compared by item so we compared and analyzed the items that implement well to quality control and the items that require attention to quality control. Results As a result of measuring the precision average of internal quality control for 42 items of six institutions, the top group (5.0% or less) are Ferritin, HGH, SHBG, and 25-OH-VitD, while the bottom group (≤10.0%) are cortisol, ATA, AMA, renin, and estradiol. When comparing more than 10.0% bounce rate of CV for tumor markers, CA-125 (6.7%), CA-19-9 (9.8%) implemented well, while SCC-Ag (24.3%), CA-15-3 (26.7%) were among the items that require attention to control. As a result of comparing the bounce rate of more than 10.0% of CV for thyroid hormones examination, free T4 (2.1%), T3 (9.3%) showed excellent performance and AMA (39.6%), ATA (51.6%) required attention to control. When comparing the bounce rate of 10.0% or more of CV for other hormones, IGF-1 (8.8%), FSH (9.1%), prolactin (9.2%) showed excellent performance, however estradiol (37.3%), testosterone (37.7%), cortisol (44.4%) required attention to control. As a result of measuring the average CV of the whole institutions participating at external quality control for 28 items, HGH and SCC-Ag were included in the top group (≤10.0%), however ATA, estradiol, TSI, and thyroglobulin included in bottom group (≥30.0%). Conclusion As a result of evaluating 42 items of six institutions, the average CV was 3.7~12.2% showing a 3.3 times difference between the upper group and the lower group. Cortisol, ATA, AMA, Renin and estradiol tests with high CV will require continuous improvement activities to improve precision. In addition, we measured and compared the overall average CV of the internal quality control, the external quality control and the proficiency between institutions participating of six institutions for 41 items excluding HBs-Ab. As a result, ATA, AMA, Renin and estradiol belong to the same subgroup so we require attention to control and consider setting a higher acceptable range. It is recommended to set and control the acceptable range standard of internal quality control CV in consideration of many things in the laboratory due to the different reagents and instruments, and the results vary depending on the test's proficiency and quality control materials. It is thought that the accuracy and reliability of radioimmunoassay results can be improved if systematic quality control is implemented based on the set acceptable range.