• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.145-152
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• 2014

The usage of textile-based sensors has increased due to their many advantages (compared to IT sensors) when applied to body assessment and comfort. Textile-based sensors have different detecting factors such as pressure, voltage, current and capacitance to investigate the characteristics. In this study, textile-based sensor fabrics with sheath-core type conductive yarns were produced and the relationship between capacitance changes and applied load was investigated. The physical and electric properties of textile-based sensor fabrics were also investigated under various laminating conditions. A textile based pressure sensor that uses a sheath-core conductive yarn to ensure the stability of the pressure sensor in the textile-based sensor (the physical structure of the reaction characteristic of the capacitance) is important for the stability of the initial value of the initial capacitance value outside the characteristic of the textile structural environment. In addition, a textile based sensor is displaced relative to the initial value of the capacitance change according to pressure changes in the capacitance value of the sensor due to the fineness of the high risk of noise generation. Changing the physical structure of the fabric through the sensor characteristic of the pressure sensor via the noise generating element of laminating (temperature, humidity, and static electricity) to cut off the voltage output element to improve the data reliability could be secured.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.505-511
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• 2006

In the present paper, approximate plastic limit load solutions fur pipe bends under combined internal pressure and bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. The present FE results show that existing limit load solutions for pipe bends are lower bounds but can be very different from the present FE results in some cases, particularly for bending. Accordingly closed-form approximations are proposed for pipe bends under combined pressure and in-plane bending based on the present FE results. The proposed limit load solutions would be a basis of defective pipe bends and be useful to estimate non-linear fracture mechanics parameters based on the reference stress approach.

• Structural Engineering and Mechanics
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• v.9 no.1
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• pp.51-68
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• 2000

The paper presents theoretical and experimental investigations on three varying thickness circular cylinders, which were tested to destruction under external hydrostatic pressure. The five buckling theories that were presented were based on inelastic shell instability. Three of these inelastic buckling theories adopted the finite element method and the other two theories were based on a modified version of the much simpler von Mises theory. Comparison between experiment and theory showed that one of the inelastic buckling theories that was based on the von Mises buckling pressure gave very good results while the two finite element solutions, obtained by dividing the theoretical elastic instability pressures by experimentally determined plastic knockdown factors gave poor results. The third finite element solution which was based on material and geometrical non-linearity gave excellent results. Electrical resistance strain gauges were used to monitor the collapse mechanisms and these revealed that collapse occurred in the regions of the highest values of hoop stress, where considerable deformation took place.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.401-402
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• 2006

In the present paper, approximate plastic limit load solutions for pipe bends under combined internal pressure and bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. The present FE results show that existing limit load solutions for pipe bends are lower bounds but can be very different from the present FE results in some cases, particularly for bending. Accordingly closed-form approximations are proposed for pipe bends under combined pressure and in-plane bending based on the present FE results. The proposed limit load solutions would be a basis of defective pipe bends and be useful to estimate non-linear fracture mechanics parameters based on the reference stress approach.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.98-105
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• 1999

The Pressure-based Unstructured-grid Navier-Stokes Solver PUNS-2/3D for incompressible steady and unsteady viscous flows has been developed. It is based on nonstaggered cell-centered finite volume method. Second-order upwind scheme with least-square reconstruction is used for convective fluxes. The SIMPLE method is implemented to couple the pressure and velocity fields. And the time derivatives in the momentum equations are discretised using a second-order Euler backward-differencing scheme. The discretised linear equations are solved by the preconditioned Biconjugate Gradient Stabilized method(Bi-CGSTAB). The developed solver is applied to validation problems using hybrid meshes.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.595-599
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• 2010

Purpose: Trochanteric pressure sores management has been improved through the development of musculocutaneous flaps. But it has many drawbacks such as donor site morbidity and functional muscle sacrifice. With the introduction of perforator flap, it is possible to use in every location where musculocutaneous perforators are present. We have reconstructed trochanteric pressure sores using perforator-based flaps from the ascending branch of lateral circumflex femoral artery. Methods: Between May of 2006 and April of 2008, we performed six cases of perforator-based flap from the ascending branch of lateral circumflex femoral artery for the coverage of trochanteric pressure sores. For identifying perforators, a line was drawn from the anterior superior iliac spine to the superolateral border of the patella as the vertical axis, from the pubis to the trochanteric prominence as the horizontal axis. In the lateral aspect of the intersection of these two axes, various flap were designed according to its defects. The flap was raised in the subcutaneous plane above the fascia and the pedicle was traced by doppler and identified. The pedicle was meticulously dissected not to injure the periadventitial tissues and transposed to the defect. The donor site was closed primarily. Results: The mean age of patients was 56.2 years. Four male and two female patients were studied. Five patients were paraplegic. The mean defect size was $6{\times}4\;cm$. The largest flap dimension was $14{\times}7\;cm$. Donor sites were closed primarily without any complications. All flaps survived completely without necrosis, hematoma or infection. There were no recurrence during the follow-up period. Conclusion: Trochanteric pressure sores using perforator-based flap from the ascending branch of lateral circumflex femoral artery can be performed safely and it would be a reliable option for coverage of trochanteric pressure sores with minimal donor site morbidity.

• Journal of Korean Foot and Ankle Society
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• v.24 no.3
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• pp.113-119
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• 2020

Purpose: A flatfoot that fails to form a longitudinal foot arch is a common lower limb deformity in children. This study evaluated the structural and functional effects of the insole for pediatric flexible flat foot (PFFF). Materials and Methods: Twenty-nine PFFF patients (20 boys and 9 girls, 58 feet) with bilateral symptomatic flatfoot deformities between February 2017 and May 2019 were included in this study. Sixteen patients (32 cases, study group) were treated with a pressured based 3-dimensional printing insole, and 13 patients (26 cases, control group) were followed up regularly without any treatment. Flatfoot was diagnosed by a lateral talo-first metatarsal angle of more than 4° in convex downward and talocalcaneal angles of more than 30° and a calcaneal pitch of less than 20°. The foot pressures, including the midfoot pressure, total foot pressure, and the ratio of the midfoot pressure to the total foot pressure, were evaluated by pedobarography. The clinical scores were assessed using the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS), and Pediatrics Outcomes Data Collection Instrument (PODCI) scores. Results: The mean age of the study group was 9.16 years, and the mean age of the control group was 7.73 years. The mean follow-up period was 16 months. The change in the lateral talocalcaneal angle was -4.664°±1.239° in the study group and -0.484°±1.513° in the control group. A significant difference in the amount of change of the lateral talocalcaneal angle was observed between the two groups (p=0.034). The midfoot pressures were similar in the two groups. Conclusion: Pressure based customized 3-dimensional printing insole in PFFF may have some effect on the hindfoot bony alignment, but it does not affect the changes in midfoot pressure.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.466-470
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• 2007

Purpose: Active prevention is an essential component in reducing the development of pressure sores. For the high-risk patient group, following the certified pressure sore screening scale as well as educating the patient and the nurses who care for them can lead to optimal management of these patients. Applying a risk assessment scale along with a prevention strategy can reduce medical costs and length of stays at the hospital. The purpose of this study is to evaluate the efficacy of a new pressure sore risk assessment scale based on the universally recommended Braden scale and our prevention program. Methods: From June to August, 2003, our pressure ulcer risk assessment scale was applied to a total of 1882 patients admitted to the experimental group (intensive care unit, neurosurgery, general surgery, and oncology units). It was based on Braden scale. We analysed sensitivity, specificity, positive and negative predictive value and ROC curve to evaluate its efficacy. Pressure ulcer prevention program was composed of patient's education using protocol and specific nursing care. The incidence of pressure ulcers was also measured during the 3 months period, and those were compared to the control group of 1789 patients from March to May, 2002. Results: 118(6.27%) of the experimental group were high-risk with an incidence of pressure ulcers measuring 4 (0.21%). Sensitivity, specificity, positive and negative predictive value of our scale were 100%, 94%, 4%, 100%, respectively, and AUC(area under the curve) was 0.992. In the control group, the incidence of pressure ulcers was 11(0.61%). Statistical analyses using chisquared tests with a significance level of 5%, the results were such that ${\chi }^2=3.6482$(p=0.0561). The results proved to be statistically significant in borderline. Conclusion: The results from this study proved that pressure sore risk assessment scale based on Braden scale has an excellent efficacy, and shows that our pressure ulcer prevention program is partially effective in reducing pressure ulcer incidence.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.411-417
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• 2000

This paper describes the analysis of the oscillometric method based on the shape of arterial pressure and proposal of a new algorithm for estimating the blood pressure by computer simulation. In the first step, the arterial pressure model which is able to control the shape of arterial pressure was designed and then we simulated the oscillometric model using both the existing exponential model showing the static arterial pressure-volume relation and the designed arterial pressure model. By analyzing the correlation of characteristic ratio based on the shape of arterial pressure, we could find that the characteristic ratio was not the only standard parameter for estimating systolic and diastolic pressure. We were able to estimate the shape of arterial pressure by computing the correlation of arterial pressure shape with oscillation shape. Finally, we proposed an algorithm which is able to estimate systolic and diastolic pressure according to pressure(Pp) table constructed from the relation of maximum amplitude of oscillation and arterial pressure shape. We tested 60 arterial pressure waveforms having various arterial pressure shape and pulse. As a results, the absolute deviation average values of the estimation of systolic, diastolic and mean pressure were 1.62%, 2.40% and 2.20%, respectively. In conclusions, the proposed algorithm showed the possibility of usefullness in estimating the blood pressure.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.118-125
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• 2009

Calculation of indicated mean effective pressure(IMEP) requires high cylinder pressure sampling rate and heavy computational load. Because of that, it is difficult to implement in a conventional electronic control unit. In this paper, a cylinder pressure based real-time IMEP estimation method is proposed for controller implementation. Crank angle at 10-bar difference pressure($CA_{DP10}$) and cylinder pressure difference between $60^{\circ}$ ATDC and $60^{\circ}$ BTDC($DP_{deg}$) are used for IMEP estimation. These pressure variables can represent effectively start of combustion(SOC) and fuel injection quantity respectively. The proposed IMEP estimation method is validated by transient engine operation using a common-rail direct injection diesel engine.