• The Bulletin of The Korean Astronomical Society
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• v.21
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• pp.7-7
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• 1996

• Journal of Korean Physical Therapy Science
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• v.27 no.1
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• pp.51-55
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• 2020

Background: A typical plank exercise (PE) strengthens the core muscles, stabilizes the spinal column, and provides stability around the pelvis and trunk when the trunk is aligned. However, because PE require that the hip joint be kept straight, they can activate the hamstring (HAM). Excessive HAM activation can induce tightness, which may cause low back pain. Therefore, it is necessary to explore PE methods that can minimize HAM activity while maximizing core muscle activity. Design: Cross-sectional study. Methods: This study included 30 healthy adults as subjects. We measured the activity of the HAM and the erector spinae (ES), rectus abdominis (RA), and external oblique (EO) muscles using surface electromyography during three PEs (typical PE, PE with balance pad, and PE with sling). Results: The RA, EO, and ES showed the highest muscular activity during PE with balance pad and the lowest during PE with sling; however, the differences were not significant. The HAM showed lower activity during PE with sling than during the other two PEs; however, these differences were also not significant. Conclusion: Although HAM activation was not significantly difference among PE positions, we should recognize altering activation of core and hamstring muscle according to PE postures.

• Smart Structures and Systems
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• v.15 no.3
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• pp.769-785
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• 2015

Although timber structures have been extensively used in underground temporary supporting system, their actual performance is poorly understood, resulting in potentially conservative and over-engineered design. In this paper, a novel wireless sensor technology, SmartPlank, is introduced to monitor the field performance of timber structures during underground construction. It consists of a wooden beam equipped with a streamlined wireless sensor node, two thin foil strain gauges and two temperature sensors, which enables to measure the strain and temperature at two sides of the beam, and to transmit this information in real-time over an IPv6 (6LowPan) multi-hop wireless mesh network and Internet. Four SmartPlanks were deployed at the London Underground's Tottenham Court Road (TCR) station redevelopment site during the Stair 14 excavation, together with seven relay nodes and a gateway. The monitoring started from August 2013, and will last for one and a half years until the Central Line possession in 2015. This paper reports both the short-term and long-term performances of the monitored timber structures. The grouting effect on the short-term performance of timber structures is highlighted; the grout injection process creates a large downward pressure on the top surface of the SmartPlank. The short and long term earth pressures applied to the monitored structures are estimated from the measured strains, and the estimated values are compared to the design loads.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.280-286
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• 1988

Freezing is becoming incressingly important in the food industry as a means of food preservation since the turn of the century. For quality, processing and economic reasons, it is important to predict the freezing time for foods. A number of models have been proposed to predict freezing time. However, most analytical freezing time prediction techniques apply only to specific freezing conditions. Therefore, it is necessary to develop an improved analytical method for freezing time prediction under various conditions. The objectives of this study, by reviewing previous experimental data obtained by uncertain freezing condition and thermo-physical data, were to develop simple and accurate analytical method for prediction freezing time, and to obtain the freezing time of various foodstuffs by still air freezing and immersion freezing method. The result of this study showed that the proposed method offered better results than the other complex method compared.

• Journal of Korean Physical Therapy Science
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• v.26 no.3
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• pp.23-36
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• 2019

Background: The purpose of this study was to investigate the effect of Plank exercise on unstable support surfaces on flexibility, abdominal muscle thickness and pain in patients with chronic back pain. Design: Randomized controlled trial. Methods: This study was performed on 16 patients with chronic back pain of ◯◯ military unit. Sixteen subjects were randomly assigned into two groups, an upper extremity trainer group (group I, n=8) and a lower extremity trainer group (group II, n=8). The subjects in group I carried out Flank exercise applying the stability trainer to their upper extremities and ones in group II carried out the same exercise applying the stability trainer to their lower extremities for 4 weeks. In order to ascertain the difference between two groups, flexibility, abdominal muscle thickness and pain were measured before and after the exercise. The flexibility was measured by sit and reach test, the thickness of the abdominal muscle was measured by using ultrasonic imaging equipment, and the pain was measured by the visual analogue scale. A paired t-test was utilized to compare changes in pain, abdominal muscle thickness and flexibility before and after flank exercise on unstable support surfaces. Analysis of Covariance (ANCOVA) was performed for ascertaining the significant differences between groups. The significance level was set by α=.05. Results: 1) The flexibilities of two groups were increased after the exercise (p<0.05). 2) In both groups, the thicknesses of rectus abdominis, external oblique abdominis, internal oblique abdominis, and transverse abdominis were all increased after the exercise (p<0.05). 3) The pains in both groups were decreased after the exercise (p<0.05). 4) In the comparisons of two groups, there were no differences in the flexibility, thickness of external oblique abdominis, internal oblique abdominis and transverse abdominis and pain (p>0.05). Whereas only thickness of Rectus abdominis was larger in the group I than in the group II (p<0.05). Conclusion: Plank exercise on the unstable support surface for 4 weeks resulted in increased flexibility, abdominal muscle thickness and pain reduction in patients with chronic back pain. Therefore, it is considered that performing flank exercise on the unstable supporting surface is suitable for the reduction of the pain in patients with chronic back pain. However, in this study, it is considered that continuous and diverse studies are needed because there was not a large difference between the groups when the upper or lower limbs are provided unstable support surfaces.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.92-103
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• 2015

Development of new concrete bridge deck system with FRP plank using as a permanent formwork and the main tensile reinforcement recently has been actively conducted. Concurrent use as a reinforcing material and a permanent formwork, it is possible to reduce the construction time and construction costs than the usual concrete slab. In this study, an experiment was carried out for the bond stress between cast-in-place concrete and the type of FRP plank using as a permanent formwork. The interfacial fracture energy that can be one of the most important parameters were evaluated for adhesion performance and bond stress to know the characteristics of the failure mechanism of the adhesion surface. Interfacial fracture energy of normal concrete is 0.24kN/m of GF11 case, in the case of GF21, 0.43kN/m appears, in the case of CF11 and GF31, 0.44kN/m and 0.46kN/m respectively it appeared. In case of RFCON, 0.52kN/m appears from GF12, the CF12 and GF22, 0.51kN/m and 0.36kN/m appeared each case.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1285-1285
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• 2001

For NIR measurements of papers normally diffuse reflectance accessories are used which can provide a large sampling area. The in-line process control FT-NIR spectrometer MATRIX-E enables the contactless measurement of paper samples of low silicone coat weights on label-stocks in a paper converting factory. For this study concentrations of silicone between 0 and 2 g/$m^2$ on various paper substrates were included in a quantitative method. The aim was to achieve an absolute value for the deviation from the target value of 1 g/$m^2$ during continuous movement of the paper with velocities around 400 numinute. Influences from the uncoated paper type due to supplier, color, opacity, area densities, pre-coating as well as different compounds of the agent silicone were investigated and it was found that all these papers can be represented in one PLS-model. Especially the fact that silicone as an element is present in clay coated papers is of no consequence to the measurements with MATRIX-E. Moreover during in-line installations the variation of the moisture contents in the moving paper due to variable machine velocities as well as the reflecting material of the cylinder have to be considered. It is shown that the result of the in-line calibration has the same prediction ability compared to lab scale results(Root Mean Square Error of Cross-Validation RMSECV = 0.034 g/$m^2$).

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.921-926
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• 2007

A dynamic system under random disturbance is considered in the study. In order to control the system efficiently, proper reduction of system dimension is indispensible in design stage. The reduction method using component cost analysis in conjunction with stochastic analysis is proposed for the control of a system. System response is obtained in terms of dynamic moment equation via Fokker-Plank-Kolmogorov(F-P-K) equation. The dynamic moment response of the system under random disturbance are reduced by using of deterministic version of component cost analysis. The reduced system via proposed "stochastic component cost analysis" is successfully implemented for dynamic response and shows remarkable control performance effectively utilizing "stochastic controller" in physical time domain.

• The Journal of Korean Medicine
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• v.41 no.3
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• pp.151-161
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• 2020

Objectives: The purpose of this study is to report the improvement of multiple rib fracture after korean medical treatment; adhesive treatment and herb-medicine treatment. Methods: A patient with multiple rib fracture was treated with Daewhangchija-paste(大黃梔子膏) adhesive and herb-medicine treatment. Verbal numeric rating scale, medical examination by interview and rib series x-ray were used to assess progress of treatment. And we took pictures of left flank after attaching Daewhangchija-paste to observe the changes of the skin colors. Results: Rib series x-ray taken after 2 months of treatment revealed hard callus which added stability against external force on rib cage. After taking off Daewhangchija-paste, left plank skin turned into blue, green and yellow. And the pain level(VNRS) of left plank decreased from 10 to 0.5 for 4 months. Conclusions: Pain reduction on trauma site and improvement of general health condition were observed during combination treatment of Daewhangchija-paste adhesive and herb-medicine.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.80-84
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• 2017

Purpose: This study was conducted to examine the effects of different sizes of blood flow restriction areas on the thickness of the external oblique and biceps brachii. Methods: The study subjects were 52 adults who were divided into four groups that performed plank exercises over a six-week period after blood flow restriction. Changes in the thickness of the external oblique and biceps brachii were measured using ultrasonography before the experiment, then three and six weeks after the experiment. The changes in each variable over time were evaluated by repeated-measures analysis of variance (ANOVA). Results: The external oblique and biceps brachii showed significant differences in muscle thickness with regard to time and the interaction between time and each group (p<0.01), but no significant differences with regards to changes between groups (p>0.05). Conclusion: A larger blood flow restriction area resulted in a statistically significant increase in muscle thickness. The results of this study may be used as the basis for future studies and for rehabilitation in clinical practice.