• Korean Journal of Mathematics
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• v.8 no.2
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• pp.111-119
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• 2000

For a linear operator Q from $R^d$ into $R^d$. ${\alpha}$ > 0 and 0 < $b$ < 1, the Gaussian (Q, $b$, ${\alpha}$)-semi-stability of probability measures on $R^d$ is investigated.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.3
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• pp.381-391
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• 2014

In this paper, we prove the generalized Hyers-Ulam stability of an n-dimensional additive functional equation, and then apply stability results to Banach modules over a unital Banach algebras.

• The Journal of Korean Physical Therapy
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• v.27 no.1
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• pp.7-11
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• 2015

Purpose: This study was conducted in order to determine the effects of knee malalignment including genu varum, valgum, and recurvatum on static and dynamic postural stability. Methods: A total of 80 subjects were enrolled in this study. Subjects who showed over 3 cm in the distance between the knees were classified as the genu varum group, and subjects who showed over 3 cm in the distance between the ankles were classified as the genu valgum group. Subjects who showed over 1 cm in the distance between the patella and a table in prone position were classified as the genu recurvatum group. Static and dynamic stability were measured as overall, anterioposterior, and mediolateral balance index using a Biodex Balance System. Results: This study showed that knee alignment affected static and dynamic postural stability. In particular, there were significant differences in the mediolateral stability index among genu varum, valgum group, and the other groups, but no differences in overall and anteriolateral stability index. Significant differences in the anterioposterior stability index were observed between genu recurvatum and the other groups, however, there were no differences in overall and mediolateral stability index. Conclusion: The findings were that knee malalignment affects postural stability toward a specific direction. Treatment to improve postural stability for treatment of knee malalignment or to prevent falling or injuries is needed and postural stability toward a specific direction according to the knee alignment conditions should be considered.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.5
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• pp.73-84
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• 2020

In this study, we compared and analyzed the static and dynamic analysis method for agricultural reservoirs. In addition, we assumed the aging of reservoir as the deterioration of the internal friction angle and cohesion. The internal friction angle and cohesion were applied by dividing into 4 case for each reservoir. As a result of comparing the stability of the reservoir embankment, it was found that the dynamic stability analysis method showed a greater risk than the static stability analysis method when dynamic loads such as earthquakes were applied. Therefore, when detailed review such as liquefaction is required, it is considered that the dynamic stability analysis method should be applied first. If a study on the change in material properties due to the aging of the reservoir is conducted, the stability analysis of the reservoir due to the aging of the reservoir can be performed more accurately. In addition, if a study comparing the results of dynamic stability analysis and static stability analysis for earthquakes with various characteristics for more reservoirs is conducted, detailed criteria for the case where dynamic stability analysis should be considered can be presented.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1566-1577
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• 2018

This paper presents a stability analysis of AC-DC power system feeding a speed controlled DC motor in which this load behaves as a constant power load (CPL). A CPL can significantly degrade power system stability margin. Hence, the stability analysis is very important. The DQ and generalized state-space averaging methods are used to derive the mathematical model suitable for stability issues. The paper analyzes the stability of power systems for both speed control natural frequency and DC-link parameter variations and takes into account controlled speed motor dynamics. However, accurate DC-link filter and DC motor parameters are very important for the stability study of practical systems. According to the measurement errors and a large variation in a DC-link capacitor value, the system identification is needed to provide the accurate parameters. Therefore, the paper also presents the identification of system parameters using the adaptive Tabu search technique. The stability margins can be then predicted via the eigenvalue theorem with the resulting dynamic model. The intensive time-domain simulations and experimental results are used to support the theoretical results.

• Journal of the Korean Mathematical Society
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• v.49 no.3
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• pp.515-536
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• 2012

This work focuses on the general decay stability of nonlinear stochastic differential equations with unbounded delay. A Razumikhin-type theorem is first established to obtain the moment stability but without almost sure stability. Then an improved edition is presented to derive not only the moment stability but also the almost sure stability, while existing Razumikhin-type theorems aim at only the moment stability. By virtue of the $M$-matrix techniques, we further develop the aforementioned Razumikhin-type theorems to be easily implementable. Two examples are given for illustration.

• Safety and Health at Work
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• v.3 no.3
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• pp.192-198
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• 2012

Objectives: Slip and fall accidents in the workplace are one of the top causes of work related fatalities and injuries. Previous studies have indicated that fall risk was related to postural and dynamic stability. However, the usage of this theoretical relationship was limited by laboratory based measuring instruments. The current study proposed a new method for stability assessment by use of inertial measurement units (IMUs). Methods: Accelerations at different body parts were recorded by the IMUs. Postural and local dynamic stability was assessed from these measures and compared with that computed from the traditional method. Results: The results demonstrated: 1) significant differences between fall prone and healthy groups in IMU assessed dynamic stability; and 2) better power of discrimination with multi stability index assessed by IMUs. Conclusion: The findings can be utilized in the design of a portable screening or monitoring tool for fall risk assessment in various industrial settings.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.2
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• pp.43-49
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• 2000

It is a complex process to analyze power system voltage stability problems with all of the dynamics of a system, because a large power network system sophisticatedly consists of generators, lines, loads and so forth. So we considered the dynamics of loads so as to analyze voltage stability method- by carrying out an analysis of steady state voltage stability and dynamic voltage stability simultaneously. To perform a steady state voltage stability program in advance makes it possible to cut down on laborious calculations so that an analysis of dynamic voltage stability becomes concise. The validity and efficiency of the method presented in this paper were verified by applying the IEEE 14 bus system.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.181-193
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• 2020

This study examines the relationship between gender diversity (women on the board and women on the audit committee) and a firm's financial stability. The ordinary least square analysis was used to determine the relationship. To measure the financial stability of Malaysian suspect firms, i.e., firms with the lowest positive earnings, the Altman (1993) Z-Score measurement was utilized. The results indicate that women on the board are significantly and negatively associated with the firm's financial stability. That is, they are related to low financial stability, which contradicts the agency and resource dependence theories. Regarding women directors on the audit committee, there is no significant relationship with financial stability, meaning that they cannot protect the company against financial distress. These results are robust and do not change when using different measurements of gender diversity, one-year lag of independent variables, and other methods of analysis, namely random effect panel data. This study is the first to alert policymakers, stakeholders, researchers, and society in general to the need to re-evaluate and strengthen the role of women directors in improving firms' financial stability, particularly in emerging economies like Malaysia.

• Journal of Powder Materials
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• v.25 no.5
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• pp.395-401
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• 2018

The improvement of dispersion stability for the primary polishing slurry in a CMP process is achieved to prevent defects produced by agglomeration of the slurry. The dispersion properties are analyzed according to the physical characteristics of each silica sol sample. Further, the difference in the dispersion stability is confirmed as the surfactant content. The dispersibility results measured by Zeta potential suggest that the dispersion properties depend on the content and size of the abrasive in the primary polishing slurry. Moreover, the optimum ratio for high dispersion stability is confirmed as the addition content of the surfactant. Based on the aforementioned results, the long-term stability of each slurry is analyzed. Turbiscan analysis demonstrates that the agglomeration occurs depending on the increasing amount of surfactant. As a result, we demonstrate that the increased particle size and the decreased content of silica improve the dispersion stability and long-term stability.