• Journal of Power Electronics
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• v.11 no.6
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• pp.904-913
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• 2011

Previous publications regarding the design and specifications of input filters for STATCOMs usually deal with the input filter only, and seldom pay any attention to the influence of the input filters on the performance of the STATCOM systems. A detailed analysis of the influences of input filters on the stability of STATCOM systems and the corresponding design considerations are presented in this paper. Three types of input filters, L filters, LC filters, and LCL filters, are examined separately. The influences of the parameters of input filters on system stability are investigated through frequency domain methods. With direct current control taken as the major control strategy for the STATCOMs, the different situations when adopting different current detection points are covered in this analysis. A comparison between LC filters and LCL filters is also presented with optimized filter parameters. Based on the analysis, the phase margin, as one of the design considerations for the different types of input filters under different current detection schemes, is discussed. This leads to filter parameters that are different than those of the traditional design. Hardware experimental results verify the validity of the above analysis and design.

• Computational Structural Engineering
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• v.10 no.4
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• pp.195-203
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• 1997

The interaction between cracks and stress wave due to impact and explosive loads is numerically calculated in the study. The interaction and the effects of stress wave are numerically examined with the application of Bicharacteristic Method. This method has been used with confidence for its reliability in reproducing the realistic and physical wave pattern in the complete solution domain. The dynamic stress intensity factor, K/sub I/(t) for cracks under impact loads are numerically simulated and its results are compared favorably with Kalthoff's experimental output. Also the influence of stress wave to the dynamic stress intensity factor for the case of two symmetric holes around cracks are investigated. The results of study are also compared favorably with the experiment and proven to be applied to the structures exposed to impact and explosive loads.

• Journal of the Ergonomics Society of Korea
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• v.31 no.4
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• pp.557-565
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• 2012

Objective: This paper focuses on the new trend of applying NUI(natural user interface) such as gesture interaction into television and investigates on the design improvement needed in application. The intention is to find better design direction of NUI on television context, which will contribute to making new features and behavioral changes occurring in next-generation television more practically usable and meaningful use experience elements. Background: Traditional television is rapidly evolving into next-generation television thanks to the influence of "smartness" from mobile domain. A number of new features and behavioral changes occurred from such evolution are on their way to be characterized as the new experience elements of next-generation television. Method: A series of expert review by television UX professionals based on AHP (Analytic Hierarchy Process) was conducted to check on the "relative appropriateness" of applying gesture interaction to a number of selected television user experience scenarios. Conclusion: It is critical not to indiscriminately apply new interaction techniques like gesture into television. It may be effective in demonstrating new technology but generally results in poor user experience. It is imperative to conduct consistent validation of its practical appropriateness in real context. Application: The research will be helpful in applying gesture interaction in next-generation television to bring optimal user experience in.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.201-214
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• 2020

This study aims at evaluating composite moment frame structures (CFS) using wavelet analysis of the displacement behavior of these structures. Five seismic damage mitigation systems' models of 9-story CFS are examined namely, basic (Model 1), reinforced (Model 2), buckling restrained braced (BRB) (Model 3), lead rubber bearing (LRB) (Model 4), and composite (Model 5) moment frames. A novel integration between continuous and discrete wavelet transforms is designed to estimate the wavelet power energy and variance of measurements' behaviors. The behaviors of the designed models are evaluated under influence of four seismic loads to study the dynamic performance of CFS in the frequency domain. The results show the behaviors of models 3 and 5 are lower than other models in terms of displacement and frequency performances. Model 3 has been shown lower performances in terms of energy and variance wavelets along the monitoring time; therefore, Model 3 demonstrates superior performance and low probability of failure under seismic loads. Furthermore, the wavelet variance analysis is shown a powerful tool that can be used to assess the CFS under seismic hazards.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.1
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• pp.49-58
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• 2013

Recently, the design of commercial ships with less green-house gas is one of great interests in naval architecture fields. Ship designers are asked to find optimum hull forms with minimum resistance in ocean waves. The accurate computation of added resistance, therefore, is getting more important for the prediction of power increase in random ocean waves. This study focuses on the numerical computation of added resistance on ships with Ax-bow shapes which are designed to reduce added resistance. To this end, the time-domain Rankine panel methods based on weakly-nonlinear and weak-scatterer approaches are applied, which can reflect the influence of above-still-water bow shape. As computational models, KCS and KVLCC2 hull forms are considered. Each ship is combined with the three types of Ax-bow shape, and computational results are compared each other.

• Journal of Korean Academy of Nursing
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• v.34 no.1
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• pp.81-92
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• 2004

Purpose: The purpose of this study was to identify a path diagram for the influence of family, personality, sexual abuse, drug abuse, coping strategies, and aggressive impulsiveness on aggression, and to develop a sublimation program for Korean adolescent's aggression. Method: Data was collected by self-report questionnaires. Subjects consisted of 2,111 adolescents. A proportional stratified random sampling method was used. The major instrument was the Mental Health Questionnaire for Korean Adolescents, and the Cronbach's Alpha ranged from .54 to .95 for each subscale. Statistical methods were Chi-square, correlation analysis, and path analysis. Results: The strongest contributing variables on aggression were person-related aggressive impulsiveness, antisocial personality, self-injured aggressive impulsiveness, gender, sexual abuse, psychosomatic symptoms II, drug abuse, age, parent-child relationship, alcohol abuse and cognitive avoidance coping strategies in the order named. Also the author developed a multi-systemic sublimation program for Korean adolescents's aggression. The multi-systemic sublimation program involves four domains including adolescents, parents, peers and community, and has several therapeutic sub-programs for each domain. Conclusion: The ecology of human development is composed of multiple, integrated levels of organization, including biological, individual-psychological, social-interpersonal, cultural, and historical levels. Therefore, this multi-systemic sublimation program will prevent and decrease the rate of aggressive behavior among Korean adolescents.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.153-168
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• 2013

Information security has been a major concern in organizations. The longstanding question of how to improve employees security behaviors and reduce human errors remains unanswered and requires further exploration in the information security domain. To do this, we propose a risk compensation theory-based model and examine the model. Research results shows that the relationships between information security countermeasures and information security compliance intention of employees are moderated by system vulnerability. However, the finding is contrary to the previously held risk compensation assumption and deserve further study. In addition, system quality does not play a moderator role in the relationship. Conclusions and implications are discussed.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.344-355
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• 2020

Tropical cyclone scale vortices and associated Rossby waves were investigated numerically using high-resolution barotropic models on the global domain. The equations of the barotropic model were discretized using the spectral transform method with the spherical harmonics function as orthogonal basis. The initial condition of the vortex was specified as an axisymmetric flow in the gradient wind balance, and four types of basic zonal states were employed. Vortex tracks showed similar patterns as those on the beta-plane but exhibited more eastward displacement as they moved northward. The zonal-mean flow appeared to control not only the west-east translation but also the meridional translation of the vortex. Such a meridional influence was revealed to be associated with the beta gyre and the Rossby wave, which are formed around the vortex due to the beta effect. In the case of the basic zonal state of climatological mean, the meridional translation speed reached the maximum value when the vortex underwent recurving.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.94-100
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• 2018

Partial discharges (PDs) are electrical sparks that occur inside insulation between two conducting electrodes and can lead to the disastrous failure of insulation systems. To determine the location of a PD, a distributed array of UHF PD sensors is used to detect the electromagnetic (EM) signals emitted from the PD source, and the localization of the PD source can be estimated using the time difference of arrival (TDOA) between EM signals captured by the UHF PD sensor array. There are four popular methods to estimate the TDOA-the first peak method, the cross-correlation method, the energy criterion method, and the average time window threshold method. In this work, we numerically investigate the influence of noise on estimating the TDOA for the four different methods. Numerical results show that the energy criterion method is more robust against noise than other methods.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.551-559
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• 2014

The influence of the battle damage hole on the velocity and vorticity flow field have been studied by using particle image velocimetry. Time averaged velocity and vorticity vector fields in the vicinity of jet are presented. The perforated damage hole on a wing created from a hit by anti-air artillery was modeled as a 10% chord size hole which positioned at quarter chord. At low angles of attack, the vorticity in the forward side of the jet is cancelled due to mixing with the wing surface boundary layer. Stretching of vorticity in the backside of the jet generates a semi-cylindrical vortical layer that enclosing a domain with slow moving reverse flow. Conversely, at higher the angles of attack, the jet vorticity advected away from the wing surface and remains mostly confined to the jet. The mean flow behind the jet has a wake-like structure.