• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.453-459
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• 2009

The DSME guide plate(GP) has been developed with the target to improve the cavitation and vibration performance when used with discharging cooling water around the outlet of LNG carrier. It was proven that it could as well be applied as a powerful wake control device on its own, even without discharging cooling water. However, it has to be taken into account that it inevitably results in speed loss. This study shows the possibility to design a GP which simultaneously improves both vibration and speed performance. The study intends to outline how to design the preliminary GP configurations from both the vibration and the speed performance points of view. Further, the study offers design guidance for the hull form and the propeller when adapting GP as a wake control device.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1323-1329
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• 2011

The purpose of study was to analyze how the visual information affects balance control of individuals during single leg stance. A total of 27 young normal people (20 males and 7 females, age: $13.7{\pm}2.6$, height: $162.3{\pm}13.2$ cm, weight: $53.9{\pm}13.9$ kg) was voluntarily involved in the experiment. The subjects were requested to maintain balance for 20 seconds with eyes both open and closed on a force plate and then foot ground reaction data were collected for that duration. Results showed that mean velocity of COP in closed eyes condition was larger 1.84 times than that of the open-eyes condition and range of vertical angle was increased approximately one degree in the closed eyes condition. To accomplish a balance, the frequency power in mediolateral and anteroposterior components of the foot-ground reaction force was increased by 1.3~1.4 times. Consequently, visual absence during single leg stance can result in critical loss of balance and lead to instability of body control.

• CELLMED
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• v.5 no.4
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• pp.27.1-27.6
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• 2015

Literatures and experimental studies have shown that Prunella has an effect on anti-hypertension, however, its components are complicated, so that it is still difficult to clear the specific roles of its various components in blood pressure regulation in. So we decide to systematically study the anti-hypertension mechanism of Prunella. We integrated multiple databases and constructed molecular interaction network between the chemical constituents of Prunella Vulgaris and hypertension based on entity grammar systems model. The network has 262 nodes and 802 edges. Then we infer the interactions between chemical compositions and disease targets to clarify the anti-hypertension mechanism. Finally, we found Prunella could influence hypertension by regulating apoptosis, cell proliferation, blood vessel development and vasoconstriction, etc. Thus this study provides reference for drug development and compatibility, and also gives guidance for health care at a certain extent.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.246-253
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• 2013

This paper addresses the technology of active flow control for stabilizing a flow field. In order for flow field modeling from the control point of view, the huge-data set from CFD(computational fluid dynamics) are reduced by using a POD(Proper Orthogonal Decomposition) method. And then the flow field is expressed with dynamic equation by low-order modelling approach based on the time and frequency domain analysis. A neural network flow estimator from the pressure information measured on the surface is designed for the estimation of the flow state in the space. The closed-loop system is constructed with feedback flow controller for stabilizing the vortices on the flow field.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.971-976
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• 2014

Haptic device can be a useful rehabilitation tool in balance training. The proposed system is composed of a body-wear smartphone, Phantom Omni(R) device, and its control PC system. Ten young healthy subjects performed balance tasks with different postures during 30 seconds with their eyes closed. An Android program on the smartphone transferred mediolateral (ML) and anteroposterior (AP) tilt angles to the PC system, which can generate haptic command through haptic device. Statistical data analysis was performed using MATLAB(R). COP (Center of Pressure) related indexes were measured to see reduction in body sway. ANOVA showed that haptic device significantly reduced body sway. Intuitive balance guidance could be generated using an economical and small-sized commercial haptic device, making the system efficient.

• Journal of Korean Library and Information Science Society
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• v.43 no.3
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• pp.239-263
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• 2012

Cooperation with public libraries for strengthening the solid foundation and the reading education of school library have been recommended in Korea. However with the immensity of the task, public libraries are under considerable pressure for the unilateral support. Under these circumstances this study developed and implemented the reading mentoring programs for school libraries with the help of public libraries, LIS schools, and Busan Metropolitan office of Education. On the basis of the result, this study analyzed the effect and the feasibility of the reading mentoring programs for improving the reading education in school libraries. This study emphasized to derive a lesson of immeasurable value from 7 months' experience in the 2 elementary schools.

• The KSFM Journal of Fluid Machinery
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• v.17 no.4
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• pp.76-80
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• 2014

PFA fluoropolymer lined technology revolutionized ball valve development and design decades ago and continues to be pivotal for many products and valve solutions in diverse industries and applications, such as chemical process, semiconductor/LCD manufacturing processes, pharmaceutical and others. Because of the extreme operating conditions such as high-temperature (${\sim}120^{\circ}C$) and high-pressure (~10 bar), the reliability of the valve is very important for minimizing in-line leakage and fugitive emissions of strong corrosive chemicals (hydrochloric acid, hydrofluoric acid, nitric acid, etc.) transported through the lines. In this study, we investigated the flow characteristics with flow coefficient in a PFA lined ball valve for different opening degrees using CFD analyses. The results should be the guidance for a new PFA lined ball valve design that will incorporate all the acclaimed and demonstrated benefits of the current design approaches.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.90-96
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• 2005

This paper presents the results of the reliability analysis of PAU (Preliminary Assembly Unit) seat of the floating Production Storage and Off1-loading Unit (FPSO) The main aim of the analysis was to demonstrate that a sufficient safety of structural members is guaranteed against PAU loads, internal and external pressure, and hull girder moments. Topside loads for PAU design are based on owner's request. According to the seat type, topside loads are classified into maximum values of same seat type for design efficiency. Totally, 26 loading cases for each model are used for this analysis with the combination of the reactions of PAU loafing and the hull girder bending moments according to LR offshore (2). The analysis results are evaluated according to the acceptance criteria for yielding given in LR offshore and guidance note (3) and The panel buckling resistance is verified by LR offshore and SDA (4). For 900,000 bbls FPSO, the PAU support foundation analysis using 3-D F.E. model is carried out to verify the structural adequacy of PAU foundation and structure members in way of PAU. The modified structures in way of PAU support are safe against considered load cases and all stresses in way of PAU support are within design criteria.

• Wind and Structures
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• v.15 no.4
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• pp.313-329
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• 2012

There have existed for a number of years good practice guidelines for the use of Computational Fluid Dynamics (CFD) in the field of wind engineering. As part of those guidelines, details are given for the size of flow domain that should be used around a building of height, H. For low-rise buildings, the domain sizes produced by following the guidelines are reasonable and produce results that are largely free from blockage effects. However, when high-rise or tall buildings are considered, the domain size based solely on the building height produces very large domains. A large domain, in most cases, leads to a large cell count, with many of the cells in the grid being used up in regions far from the building/wake region. This paper challenges this domain size guidance by looking at the effects of changing the domain size around a tall building. The RNG ${\kappa}-{\varepsilon}$ turbulence model is used in a series of steady-state solutions where the only parameter varied is the domain size, with the mesh resolution in the building/wake region left unchanged. Comparisons between the velocity fields in the near-field of the building and pressure coefficients on the building are used to inform the assessment. The findings of the work for this case suggest that a domain of approximately 10% the volume of that suggested by the existing guidelines could be used with a loss in accuracy of less than 10%.

• International Journal of Fluid Machinery and Systems
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• v.9 no.1
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• pp.28-38
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• 2016

The flexible control system for hydraulic pile hammer using main control valve is present to the requirement of rapidly reversing with high frequency. To ensure the working reliability of hydraulic pile hammer, the reversing performance of the main control valve should commutate robustness to various interfere factors. Through simulation model built in Simulink/Stateflow and experiment, the effects of relative parameters to reverse performance of main control are analyzed and the main interfere factors for reversing performance are acquired. Treating reverse required time as design objects, some structure parameters as control factors, control pressure, input flow and gaps between spool and valve body as interfere factors, the robust design of the main control valve is done. The combination of factors with the strongest anti-jamming capability is acquired which ensured the reliability and anti-jamming capability of the main control valve. It also provides guidance on design and application of the main control valve used in large flow control with interferes.