• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.135-138
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• 2018

Peroneal neuropathy scarcely can develop after massive weight reduction. A 21-year-old man complained left foot drop after 28% weight reduction (from 94 kgs to 67.5 kgs). During previous seven months, he played PC games with sitting cross-legged more than seven hours a day. In addition, he started a heavily restricted diet three months ago. Except for those, he had neither any medical history nor trauma to his knee. Electrophysiologic study showed the partial conduction block of left peroneal neuropathy at the fibular head. Four-week well balanced diet and physical therapy improved his foot drop. For the prevention of peroneal neuropathy related to weight reduction, well balanced diet and lifestyle modification are needed.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.3
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• pp.39-45
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• 2014

Dust is mostly caused by human activity. The effect of natural factors on dust emission were studied in many research, but the little effort in researching artificial factors of dust emission. The object of study is to analysis dust emission characteristic by drop impact. Particle matter $10{\mu}m$ ($PM_{10}$) was measured by drop impact on paved soil with changing drop height, weight and drop size. Increasing drop height cause more $PM_{10}$ emission. Increasing drop weight cause more $PM_{10}$ emission but had limit weight for increasing dust emission. Because the exceed kinetic energy of drop weight penetrate the soil surface. The limit perimeter was exist that separating $PM_{10}$ emission aspect. Under limit perimeter, $PM_{10}$ emission was increasing while perimeter was increasing, but over limit perimeter showed the opposite aspect. Regression equations for estimating $PM_{10}$ with kinetic energy and perimeter were made under limit perimeter and over limit perimeter. The $R^2$ of those equations were 0.784, 0.743. The error has occurred between measured $PM_{10}$ and calculated $PM_{10}$ in the equation under limit perimeter. But using equation of case for over limit perimeter, PM10 can be estimated with kinetic energy and drop perimeter.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.1-7
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• 2011

The purpose of this study was to investigate changes in kinetic and kinematic variables associated with an increase in upper body weight. Eighteen healthy male university students($175.96{\pm}4.19\;cm$, $70.79{\pm}8.26\;kg$) participated. Eight motion analysis cameras(Qualysis Oqus 500) and 2 force AMTI platforms(Advanced Mechanical Technologies Inc. OR6-7, US) were used to record motion and forces during the drop landing at a frequency of 120 Hz and 1200 Hz, respectively. QTM software(Qualisys Track Manager) was used to record the data, and the variables were analyzed with Visual 3D and Matlab 2009. For the drop landing, a box of $4{\times}2{\times}0.46\;m$ was constructed from wood. Knee and ankle maximum flexion angle, knee flexion angle, knee and ankle angle at landing, time for maximum ankle flexion after landing, and time for maximum knee flexion after landing were calculated. There was a significant change in the time for maximum and minimum ground force reaction and the time for maximum dorsal flexion after landing(p<.05) with increasing weight. There was no significant change for the hip, knee, and ankle ROM, whereas there was an increase in the angle ROM as the weight increased, in the order of ankle, knee, and hip ROM. This result shows that the ankle joint ROM increased with increasing weight for shock attenuation during the drop landing. There was a trend for greater ankle ROM than knee ROM, but there was no clear change in the ROM of the hip joint with increasing weight. In conclusion, this study shows the importance of ankle joint flexibility and strength for safe drop landing.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.303-309
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• 2000

Seismic reflection method is applied to detect shallow location of limestone in Chechon area. The data using hammer source is compared with that of weight drop. Small size hammer and weight-drop are used as energy source and 100Hz geophones are used for data aquisition. Data processing is conducted utilizing the available processing technique of "Geobit", which is seismic data processing software developed by KIGAM. The result of above data processing, the velocity of topsoil layer is 1,250m/sec. The velocity of this area is higher than other area because loading trucks pass this area and make this layer compact. And in limestone area, hammer is proposed to energy source instead of weight drop because the energy propagates the layer very well.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.335-342
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• 2003

The method of measuring ground deformation modulus, in situ-testing has the disadvantage where the exam number is limited because it needs counter weight and a lot of measurement times. Recently, it has supplemented this problem and the equipments by which measurement can be made quickly are developed and applied in field., That is Falling Weight Deflectometer(FWD), Light Drop Weight Tester(LDWT), Geogauge. Light Drop Weight Teste.(LDWT) is introduced firstly in the name of ‘a lightweight fall circuit tester for a railroad public corporation’ by KTX. Since KTX introduced LDWT, a number of research organizations have used LDWT to find out domestic standard for quality management of base ground. In this study we used ZFG 02 which was manufactured by Stendal in Germany and measured the dynamic deformation modulus in soil box and in-situ. And we analyzed the correlation of the dynamic deformation modulus with static deformation modulus based on plate test in the same ground.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.7
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• pp.369-378
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• 2018

Full-scale seismic retrofit of old and deteriorated masonry buildings requires a lot of cost and time. In such buildings, installing an emergency evacuation space can be considered as an alternative. In this study, requirements of the earthquake-proof table used as an emergency evacuation space for buildings hit by earthquake are investigated. Load conditions required for the table, including the impact effects due to building debris drop, are explained. To investigate the impact effects in more detail, weight drop test is performed for an prototype earthquake-proof table. In the test, the weight of the falling object and free fall height were considered as the main test parameters. The results showed that the duration of impact is very short (0.0226~0.0779sec), and thus the impact forces increase to 15.8~45.2 times the weight of the falling object. Based on these results, design considerations and performance verification criteria of the earthquake-proof table as an emergency evacuation space are given.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.65-78
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• 2002

The suspension polymerization of styrene was carried out to obtain the narrow-size distribution of particle by using poly(vinyl alcohol) (PVA) as suspension stabilizer according to the degree of hydrolysis and the molecular weight. The stabilizing properties of suspension are also dependent on the interfacial tension of aqueous solution when PVA is added. When the polymerization process was carried out with low hydrolyzed PVA, it gave single, well-defined particles, while high hydrolyzed PVA gave clusters. The size of particle produced in this study ranged between 5${\mu}{\textrm}{m}$ and 10${\mu}{\textrm}{m}$. The suspending agent, PVA, influences on the drop size and drop stability, When the molecular weight of PVA is increased, the drop size decreases and the drops become more stable toward coalescence. An increase in the PVA concentration decreases the mean drop size and narrows the drop size distribution.

• Journal of Korean Physical Therapy Science
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• v.26 no.1
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• pp.9-14
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• 2019

Background: Pes planus, or flat foot, causes lower limb malalignment and foot pain during walking or exercise. Therefore, a highly reliable evaluation method to accurately diagnose flat feet is necessary. This study investigated the intra-and inter-rater reliability of the navicular drop test in different postures. Design: Cross sectional study. Methods: Forty healthy volunteers performed the navicular drop test in three different combinations of non-weight-bearing and weight-bearing postures (standing/standing, sitting/sitting, and sitting/standing). Two examiners alternately performed the measurements five times in each subject, and in each posture. Significant differences in measurements were obtained among the three postures, with the highest navicular drop being observed in the sitting/standing posture. Results: Inter-rater reliability was high in the sitting/standing and sitting/sitting postures. Intra-rater reliability was high in all three postures. In the sitting/sitting and sitting/standing postures, large navicular drop values and high inter- and intra-rater reliability were observed. Conclusion: Therefore, the sitting/standing and sitting/sitting postures are recommended for use in navicular drop tests to diagnose flat feet.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.237-240
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• 2001

Dense Wavelength division multiplexing(DWDM) lightwave system requires multiplexer, demultiplexer and optical filter. In this paper, thus, we propose the Add-Drop Mux/Demux based on a Mach-Zehnder interferometer(MZI) with fiber Bragg grating(FBG). The Add-Drop Mux/Demux using FBG and MZI is able to minimize system and reduce weight. We also analyze output characteristics of Add-Drop Mux/Demux and present the optimum design data through the computer simulation.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.12-17
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• 1999

In this study, a drop-weight impact tester was manufactured to assess the strength of CFRP laminate plates. The tests were conducted on several laminates of different ply orientation. A system for the impact strength of CFRP laminates was made considering stress wave propagation theory using drop-weight impact tester as one of impact test. Results indicate that absorbed energy of quasi-isotropic specimen, haying four interfaces is higher than that of orthotropic laminates with two interfaces. Absorbed energy in the specimen that ply number, interface number and fiber stacking sequences is same but having hybrid is higher than that of orthotropic laminates without hybrid.