• Journal of the Society of Naval Architects of Korea
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• v.43 no.2 s.146
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• pp.220-227
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• 2006

In case of welding, the inherent strains are generated, because a structure experiences the plastic yielding. The inherent strain is defined as the irrecoverable strain after removing structural restraints and loading. For the analysis method of welding distortion, equivalent loading method based on inherent strain is in general use due to its efficiency and effectiveness. However, it is generally difficult to know the final strain of the welded structure if additional loadings were applied after welding. for this reason, this study introduced the concept of the hardening and added the hardening term to the equivalent loading method based on inherent strain. Therefore, the purposes of this study are to develop the inherent strain formula considering the hardening effect and to calculate residual Stresses Using Proposed inherent Strain. Also, this Study Verified the availability Of proposed inherent strain method by loading-unloading experiment on welded plate.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1322-1327
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• 2004

There are some previous studies that utilize constant impedance models or constant current models for electric trains to perform the static analysis of AT feeding systems. These mentioned models have some merits of linear systems but yield erroneous results because of the innate restraints of the models since linear models cannot represent the features of constant power in inverter-driven trains. From these reasons, it is suitable that the train be considered as a constant load model when it drives or as a constant source model when it applies regenerative brake. However, excessive rise of regenerative voltage during the braking may damage the vehicle itself and the feeding systems so the voltage must be restricted below a certain value. Keeping these facts in minds, we suggest new methods of analyzing AT feeding systems using the constant power models with the conditions of voltage constraints. The simulation results from a sample system using the proposed method illustrate both the states of system variables and the supply-demand relation of power among the trains and the systems very clearly, so it is believed that the proposed method yields more accurate results than conventional methods do.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1873-1878
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• 2007

Current differential relays may maloperate during magnetic inrush and over-excitation because a significant differential current is produced. To prevent maloperation, the relays adopt some harmonic components included in the differential current. The harmonic restraints may increase the security of a relay but cause the operating time delay of a relay when an internal fault occurs. Moreover, the operating time delay is more increased if a current transformer (CT) is saturated. This paper describes a current differential relaying algorithm for power transformer protection with a compensating algorithm for the secondary current of a CT. The comparative study was conducted with and without the compensating algorithm. The performance of the proposed algorithm was investigated when the measurement CT (C400) and the protection CT (C400) are used. The proposed algorithm can compensate the distorted current of a CT and thus reduce the operating time delay of the relay significantly for an internal fault with CT saturation.

• Genomics & Informatics
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• v.9 no.2
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• pp.74-78
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• 2011

Numerous restraints and simplifications have been developed for methods that anticipate protein structure to reduce the colossal magnitude of possible conformational states. In this study, we investigated if globularity is a general characteristic of proteins and whether they can be applied as a valid constraint in protein structure simulations with approximated measurements (Gb-index). Unexpectedly, most of the proteins showed strong structural globularity (i.e., mode of approximately 76% similarity to the perfect globe) with only a few percent of proteins being outliers. Small proteins tended to be significantly non-globular ($R^2$=0.79) and the minimum Gb-index showed a logarithmic increase with the increase in protein size ($R^2$=0.62), strongly implying that the non-globular characteristics might be more acceptable for smaller proteins than larger ones. The strong perfect globe-like character and the relationship between small size and the loss of globular structure of a protein may imply that living organisms have mechanisms to aid folding into the globular structure to reduce irreversible aggregation. This also implies the possible mechanisms of diseases caused by protein aggregation, including some forms of trinucleotide repeat expansion-mediated diseases.

• Steel and Composite Structures
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• v.20 no.1
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• pp.57-70
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• 2016

The predominant type of buckling that I-steel concrete composite beams experience in the negative moment area is distortional buckling. The key factors that affect distortional buckling are the torsional and lateral restraints by the bottom flange. This study thoroughly investigates the equivalent lateral and torsional restraint stiffnesses of the bottom flange of an I-steel concrete composite beam under negative moments. The results show a coupling effect between the applied forces and the lateral and torsional restraint stiffnesses of the bottom flange. A formula is proposed to calculate the critical buckling stress of the I-steel concrete composite beams under negative moments by considering the lateral and torsional restraint stiffnesses of the bottom flange. The proposed method is shown to better predict the critical bending moment of the I-steel composite beams. This article introduces an improved method to calculate the elastic foundation beams, which takes into account the lateral and torsional restraint stiffnesses of the bottom flange and considers the coupling effect between them. The results show a close match in results from the calculation method proposed in this paper and the ANSYS finite element method, which validates the proposed calculation method. The proposed calculation method provides a theoretical basis for further research on distortional buckling and the ultimate resistance of I-steel concrete composite beams under a variable axial force.

• PNF and Movement
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• v.6 no.1
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• pp.53-60
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• 2008

Purpose : To describes the important aspects of knee joint movement and function used when applying PNF technique to the lower limb. Method : The knee was a very important roles in the lower limb movement and ambulation. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The tibiofemoral joint is usually described as a modified hinge joint with flexion-extension and axial rotation by two degrees of freedom movement. These arthrokinematics are a result of the geometry of the joints and the tension produced in the ligamentous structures. The patellofemoral joint is a sellar joint between the patella and the femur. Stability of the patellofemoral joint is dependent on the passive and dynamic restraints around the knee. In a normal knee the ligaments are inelastic and maintain a constant length as the knee flexes and extends, helping to control rolling, gliding and translation of the joint motions. Conclusions : It is important to remember that small alterations in joint alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Successful treatment requires the physical therapist to understand and apply these arthrokinematic concepts. When applied to PNF low extremity patterns, understanding of these mechanical concepts can maximize patient function while minimizing the risk for further symptoms or injury.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.151-160
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• 2008

Purpose: The purpose of this study was to investigate factors related to delirium occurrence in the ICU patients. Method: The sample were 99 patients in the ICU in a university affiliated hospital located in Kyunggi-do. Data were collected from September $1^{st}$ to October $31^{st}$, 2006. The instrument, CAM-ICU developed by Ely et al.(2001) was utilized. Data were analyzed by SPSS 13.0 for descriptive statistics, t-test, chi-square and multiple regression. Results: The delirium in the ICU patients was occurred in 22 (22.2%) out of 99 patients. There were significant differences in factors related to delirium occurrence, such as past medical history, long hospitalization, long ICU hospitalization, restraints, intubation or tracheostomy experience, ventilator experience, high pain score, and high anxiety score. Duration of ICU hospitalization, level of anxiety and past medical history were the significant predictors of the delirium occurrence(${\ss}$=44.5%). Conclusion: This study results recommend that specific nursing strategies needed to be developed to increase the detection of delirium in the ICU patients. The ICU nurses should recognize the incidence of delirium and prevent it in ICU settings.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.99-105
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• 2004

The car seat head restraint is used for neck injury(whiplash injury) prevention in rear end impacts. The purpose of this study was to evaluate the seat head restraints for the total number of 34 domestic cars. H-POINT machine and HRMD(head restraint measuring device) were applied to measure backset(the distance between head and seat head restraint) and height(height gap between head and seat head restraint). For tendency study of driver's head position, we took the 320 driver's pictures in the street. As results, There were only five percent drivers in good and acceptable zone. For car seat head restraint system, the results was 9 cars for good zone, 10 cars for acceptable zone, 9 cars for marginal zone and 6 cars for poor zone were evaluated. For a precise evaluation the of whiplash injury, detailed FE neck model will be developed and the clinical database should be constructed for model validation.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.371-377
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• 2019

A flexible piezoelectric energy harvester(f-PEH) that converts tiny mechanical and vibrational energy resources into electric signals without any restraints is drawing attention as a self-powered source to operate flexible electronic systems. In particular, the nanocomposites-based f-PEHs fabricated by a simple and low-cost spin-coating method show a mechanically stable and high output performance compared to only piezoelectric polymers or perovskite thin films. Here, the non-piezoelectric polymer matrix of the nanocomposite-based f-PEH is replaced by a P(VDF-TrFE) piezoelectric polymer to improve the output performance generated from the f-PEH. The piezoelectric hybrid nanocomposite is produced by distributing the perovskite PZT nanoparticles inside the piezoelectric elastomer; subsequently, the piezoelectric hybrid material is spin-coated onto a thin metal substrate to achieve a nanocomposite-based f-PEH. A fabricated energy device after a two-step poling process shows a maximum output voltage of 9.4 V and a current of 160 nA under repeated mechanical bending. Finite element analysis(FEA) simulation results support the experimental results.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.21-27
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• 2019

Rockburst disasters pose serious threat to mining safety and underground excavation, especially in China, resulting in massive life-wealth loss and even compulsive closed-down of some coal mines. To investigate the mechanism of rockbursts that occur under a state of static forces, a stress model with sidewall as prototype was developed and verified by a group of laboratory experiments and numerical simulations. In this model, roadway sidewall was simplified as a square plate with axial compression and end (horizontal) restraints. The stress field was solved via the Airy stress function. To track the "closeness degree" of the stress state approaching the yield limit, an unbalanced force F was defined based on the Mohr-Coulomb yield criterion. The distribution of the unbalanced force in the plane model indicated that only the friction angle above a critical value could cause the first failure on the coal in the deeper of the sidewall, inducing the occurrence of rockbursts. The laboratory tests reproduced the rockburst process, which was similar to the prediction from the theoretical model, numerical simulation and some disaster scenes.