• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.156-162
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• 2000

Sensitized STS 304 stainless steel crack growth rate(CGR) in high temperature water was investigated under trapezoidal wave loading test using fracture mechanics techniques. The CGR, due to stress corrosion cracking(SCC), were systematically measured as a function of the stress intensity factor and stress. holding time under trapezoidal wave loading. In high temperature water, CGR was enhanced by a synergistic effects in combination with an aggressive environment and mechanical damage. The CGR, $(da/dN)_{env}$ was basically described as a summation of the environmentally assisted crack growth rate $(da/dN)_{SCC}$, $(da/dN)_{CF}$ and fatigue crack growth rate in air $(da/dN)air,. The CGR, $(da/dN)_{env}$, increased linearly with increasing stress holding time. The CGR, $(da/dN)_{SCC}$ decreased linearly with increasing stress holding time. Fracture surface mode varied from trans-granular cracking to inter-granular cracking with increasing stress holding time.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.49-57
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• 2009

This paper has proposed Flow Holding Time based Link State Update(LSU) Algorithm that can improve the performance of the existing LSU algorithms. As the existing LSU algorithms are based on the network traffic information, the proposed algorithm is based on flow holding time so we can minimize the LSU message overhead and has not had a strong influence on the depreciation of QoS routing performance. We apply a flow holding time in order to decrease the number of LSU message. We have evaluated the performance of the proposed model and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Journal of Korea Foundry Society
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• v.24 no.5
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• pp.290-294
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• 2004

The effect of carbon equivalent on the fading behavior of hypoeutectic ductile cast iron was investigated. The carbon content was slightly increased right after graphite spheroidization treatment and remained almost constant with holding at $1,490^{\circ}C$ after 4 minute. The residual magnesium content was decreased slowly with holding. The empirical equation expressing the relationship between this and holding time was proposed ; $C=C_o-P{\times}t$. The proportionality constant, P, was inversely proportional to carbon content.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.236-239
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• 2001

In thixoforming, the globule size is determined by the hoding time of last reheating stage. In this study, some experiments to investigate the relationship between the mechanical properties and the holding time were performed A357, A390 and A3l9 alloys are used in this study. This paper shows the evolution of the microstructure according to the holding time of last reheating stage. Tensile test was performed for each reheating condition to examine the effect of globule size.

• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.17-24
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• 2016

In this paper, we propose a AH LSU(Advanced Hybrid QoS Routing Link State Update) Algorithm that improves the performance of Hybrid LSU(Hybrid QoS Link State State Update) Algorithm with statistical information of flow holding time in network. AH LSU algorithm has had both advantages of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. It has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and include MLMR(Meaningless LSU Message Removal) mechanism. MLMR mechanism can remove the meaningless LSU message generating repeatedly in short time. We have evaluated the performance of the MLMR mechanism, the proposed algorithm and the existing algorithms on MCI simulation network. We use the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Physical Therapy Korea
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• v.18 no.1
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• pp.9-17
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• 2011

The purpose of this study was to assess visual biofeedback's influence on trunk muscles' (EMG) activity and endurance holding time for correct position during whole-body tilt exercise. For the study, we recruited 14 volunteers who showed no symptom of lumbar disease during medical tests. We measured the EMG activity of their rectus abdominis, external abdominal oblique, internal abdominal oblique and erector spinae muscles, and their endurance holding time for correct position during $40^{\circ}$ anterior and posterior whole-body tilt under two conditions: whole-body tilt with and without visual biofeedback. Resistance with gravitational force on the trunk during whole-body tilt was applied by using a device that had a monitor on which the subjects could check their alignment and that sounded an alarm if a subject's alignment collapsed. The study showed an increase in the EMG activity of external abdominal oblique, internal abdominal oblique/rectus abdominis ratio and endurance holding time for correct position during both $40^{\circ}$ anterior and posterior whole-body tilt with visual biofeedback compared with without visual biofeedback (p<.05). We suggest that the whole-body tilt exercise with visual biofeedback could be a beneficial strategy for selectively strengthening the internal abdominal oblique muscle and minimizing the rectus abdominis muscle's activity while maintaining correct alignment during whole-body tilt exercise.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.61-71
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• 2011

This study was conducted to estimate the shelf-life of Kimbab manufactured using a Hazard Analysis and Critical Control Point (HACCP). We performed a microbiological verification after applying the HACCP plan to Kimbab. Additionally, the shelf-life of Kimbab at each holding temperature was calculated as a regression equation between the aerobic plate counts and holding time during the storage period. The critical control points of the HACCP plan, that were applied to Kimbab, included: cold-holding of refrigerated foods, checking the endpoint cooking temperature of heated food, and cold-holding of cooked foods. As a result of the microbiological verification of Kimbab, the aerobic plate counts averaged 3.46 log CFU/g. In contrast, the coliforms, E. coli, Staphylococcus aureus, and Salmonella spp. were not detected in any of the samples. The estimated shelf-life of Kimbab was calculated to be 45 hours at $10^{\circ}C$, 29 hours at $15^{\circ}C$, 6 hours at $25^{\circ}C$ and 3 hours at $35^{\circ}C$. In conclusion, manufacturers should apply a prerequisite program and a HACCP system for a safe consumption of ready-to-eat foods and label products with a proper shelf-life. Distributors should control the proper holding time-temperature until sale and consumers should eat immediately after purchasing ready-to-eat foods.

• Korean Institute of Interior Design Journal
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• v.20 no.4
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• pp.174-182
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• 2011

This study analyzed visitors' behaviors in the viewpoint of Attraction Power and Holding Power of exhibits on the basis of exhibition layout of real science museums. Through the analysis, the study grasped efficiency of analysis index and exhibition environment elements which might have an effect on planning the exhibition space of a large-scale museum and producing detailed ranges of exhibition. The main indicators used are: 1. Attraction Power: it indicates the relative incidence of people who have stopped in front of an object/exhibit during the exhibition tour. It is calculated by dividing the number of people who stop by the total number of people who have visited the museum or gallery. 2. Holding Power: it measures the average time spent in front of an information/communication element. It is calculated by dividing the average time of stay by the time "necessary" to read an element. As a result of analyzing the exhibition areas of National Science Museum (Daejeon) and National Museum of Emerging Science and Innovation(Tokyo), the Holding Power was found to be relatively lower than the Attracting Power. This means that 3.5 out of 10 visitors stop in front of the exhibit in 6 exhibition areas, and among these, only 1/10 is used when compared to the user required time of the exhibits. In other words, like the method of deriving an analysis index, the stage of viewing can be categorized as Attracting Power and Holding Power, and because the stage from Attracting Power to the stage of Holding Power are strongly linked, it shows that it is not easy to display a meaningful result. Except, the general distribution of Attracting Power was shown to be high from the entrance area of the exhibition hall based on the standard of viewing sequence. Also, the Holding Power became sequentially lower according to the sequence of exhibition viewing and displayed a meaningful interrelationship with the distribution ratio of island exhibits. In the case of island exhibition method, it is less influenced by the movement flow of visitors when compared to the wall type method of exhibition and can be understood as an exhibition method that provides spatial chances enabling stopping and viewing.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.91-98
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• 2023

Purpose : The purpose of this study was to investigate the effect of the posture holding band on muscle activity of the rectus femoris, medial vastus, and vastus lateralis muscles and weight distribution during squat exercise. Methods : This study was conducted with 30 healthy adult men and women in their 20s, and all subjects were randomly assigned to the experimental group and the control group. Squat exercise was performed for 6 weeks. The experimental group received squat exercise while wearing a posture holding band, and the control group applied without wearing a posture holding band. Muscle activity of the quadriceps femoris (rectus femoris, vastus medialis, and vastus lateralis) and weight distribution (knee flexion 0 °, 30 °, 60 °, and 90 °) was measured. Results : According to the results of this study, all three muscles showed a main effect on time and group, and a significant interaction was shown only in the vastus lateralis. In addition, the value of the weight distribution difference according to the knee flexion angle did not show a main effect according to time and group at 30 ° of knee flexion, but showed an interaction. Conclusion : It was confirmed that the application of the posture holding band during squat exercise increased the muscle activity of the quadriceps muscle, and showed greater changes in the vastus lateralis muscle. In addition, it was confirmed that the difference in weight distribution was reduced in the knee flexion, and in particular, a greater change was shown in reducing the difference in weight distribution in the knee flexion of 30 °. Therefore, it is considered that the effect of the exercise can be further enhanced if the unnecessary movement of the trunk is controlled by using equipment such as a posture holding band during squat exercise.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.271-281
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• 2011

Purpose: The aim of this study is to investigate the changes in hardness and microstructure of a dental multipurpose alloy after simulated complete firing with controlled cooling rate and holding time by characterizing the changes in hardness and microstructure after simulated firing with various cooling rates and holding times. Methods: Before hardness testing, the specimens were solution treated and then were rapidly quenched into ice brine. The specimens were completely fired in furnace. Hardness measurements were made using a Vickers microhardness tester. The specimens were examined at 15 kV using a field emission scanning electron microscope. Results: The maximum hardness value was obtained at stage 0 after simulated firing with various cooling rates (quick cooling, stage 0, stage 1, stage 2, stage 3). By the repetitive firing, the hardness of the tested alloy decreased gradually. By holding the specimen at $500^{\circ}C$ for 10-20min after simulated firing, the hardness increased apparently. However, to hold the alloy for long periods of time in the relatively high temperature after simulated firing resulted in the formation of thick oxidation layer. The oxide film formed on the surface of the alloy after simulated complete firing with controlled cooling rate, which was mainly composed of O and Zn. Conclusion: It is reasonable to hold the alloy at $500^{\circ}C$ for 10-20min after complete firing in other to improve the final hardness of the alloy.