• Journal of the Korean Institute of Gas
• /
• v.13 no.1
• /
• pp.1-8
• /
• 2009

Recently, the vibration of underground structure due to high speed railway loads has been increased substantially as compared with middle and slow speed. The buried gas pipelines under continuous impact forces and repeated loading are more influenced by the vibrational loads than another pipelines. However, the static analysis was not enough to allow for the effect of vibrations because it uses impact factors for the design or analysis process. In this study, characteristics of Pipelines was quantitatively estimated through each conditions of soil covers and train speed, and the new vibration prediction is presented about the vibrational velocity.

• The Journal of the Acoustical Society of Korea
• /
• v.15 no.4
• /
• pp.12-17
• /
• 1996

With the increase in discomfort of living by serious traffic noise pollution, the desire of relieving from discomfort is boosted up more than ever. For this reason, the researches on environmental impact assessmient and noise pollution control are highly required. This research was aimed to analyze the physical characteristics of noise caused by high-speed train in foreign countries by literature survey and field data. And with the attained results, the exterior noise level around Chon-An station, the first station planned for the high-speed train in this country, was estimated. The results of this study might be used as a tool for predicting the unavoidable noise, lessening the noise impact caused by the high-speed train, and preparing the noise prevention measures for the interior space and the exterior around stations.

• Journal of Digital Convergence
• /
• v.12 no.9
• /
• pp.465-474
• /
• 2014

This research aimed to enhance the effects of training through the use of infrared cameras located at anterior and posterior positions. The results were as follows. In the case of the smash, the impact time needed to be adjusted to raise their impact point. The smash of S1, on the other hand, was a step smash, which showed the fastest racquet head speed and the greatest transmission of power upon impact. As the max racquet speed upon impact and during speed was similar, S1 showed the best impact time. All athletes except S6 were shown to use their right foot as their 1 step that was located in front upon landing, using a hop step as their first step. For the best swing upon stroke, it is important to make the best conditions possible for the use of elbow joints and wrist joints. The rotating radius of the racquet should be big and the shuttlecock should be fast. Balance is important in footwork, or the coordinated movement of the feet. Without a correct step it is difficult to execute an efficient stroke. In an actual game, steps need to be executed in 2 to 4 steps, and programs focusing on steps according to situation, agility and reaction need to be executed.

• Polymer(Korea)
• /
• v.25 no.5
• /
• pp.744-753
• /
• 2001

One of the most important factors which affect the impact strength of high impact polystyrene (HIPS) is the rubber-phase particle size and size distribution. In this study, HIPS was prepared from a batch reactor to observe the influence of reaction conditions such as rubber content, agitation speed and prepolymerization time on the particle size and size distribution. Measurements concerning the particle size distribution were conducted using a particle size analyzer. Due to swelling, the particle suspended in toluene increases in size with lower heat-treatment temperature and shorter heat-treatment time, while the particle in methyl ethyl ketone shows quite reasonable size without any effort of heat-treatment. As rubber content increases, the average particle size increases substantially, but the increase in agitation speed at lower rubber contents does not have much influence on the size. However, the polystyrene-phase particles occluded in rubber-phase become more uniform as agitation speed increases. Longer prepolymerization time produces rubber-phase particles with narrower particle size distribution.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.6
• /
• pp.1050-1057
• /
• 2016

SNS (Social network service) characteristics are perceived to simplify use. We carried out empirical studies on these parameters to observe the impact on the image of catering SNS online by word-of-mouth. The subjects of the study were as follows: 32.3% (392 persons) 19 years old, 67.7% (821 persons) over 19 years, 51.0% (619 persons) in their 20s, 22.1% (268 persons) in their 30s, 17.6% in their 50s, and 9.3% (112 persons) over 50 years. After verifying the hypothesis proposed that SNS characteristics perceived the ease of use, the significant factor identified in usability were connectivity Speed (${\beta}=0.213$), playfulness (${\beta}=0.246$), information (${\beta}=0.115$), and reciprocity (${\beta}=0.357$). Dual reciprocity had the most impact. It was observed that a longer impact of these significant factors improved the feel and fun of use. If SNS companies cater to, quick and easy, diverse, reliable and latest information, they can increase the ease of use, and availability, depending on the goals. Also, significant factors in the SNS features and online word of mouth was playfulness (${\beta}=0.312$), information (${\beta}=0.207$), reciprocity (${\beta}=0.066$) and perceived ease of use, and usefulness (${\beta}=0.293$), double playfulness had the maximum impact. These features provided more fun, reliable information, and could quickly deliver the latest information. The more the perceived usefulness, and ease of use, higher was the online word-of-mouth effect. SNS usage characteristics of connectivity Speed did not show any statistical significance in online word-of-mouth. Thus, catering businesses need to find ways to increase the ease of use, make the usefulness multifaceted, constantly checking the catering information on the SNS and ensuring to get the latest information is from diverse and reliable sources. This would increase the fun for the customer making the SNS to actively be utilized as a marketing tool.

• Journal of the Korean Society for Railway
• /
• v.14 no.6
• /
• pp.535-544
• /
• 2011

The rail surface defects can cause the high impact load on the track and lead to the progress of the rail fatigue damage and the rail break. In case of the rail break, there is a great deal of risk for derailment, and thus the maintenance criteria for the rail surface defects are of great importance. In this study, using the dynamic train-track interaction analysis program, the impact wheel loads and rail bending stresses according to the depths of the surface defects have been calculated with the input data of the rail surface irregularities measured at 43 spots with surface defects in the ballasted track of high-speed railway. Considering the irregularity of track geometry, the allowable limits of wheel load and rail bending stress have been set, and the maintenance criteria for the rail surface defects was suggested by analyzing the relationship of the maximum values of wheel load and rail bending stress versus depth and width of rail surface defect. The analysis results suggest that the allowable depth of the surface defect is determined approximately 0.2mm from the limit of the impact wheel load.

• Asia-Pacific Journal of Business
• /
• v.15 no.3
• /
• pp.101-120
• /
• 2024

Purpose - The purpose of this study was to examine the influencing factors on the revisit intention of unmanned convenience stores for Chinese consumers who use unmanned convenience stores. The effect of unmanned convenience store characteristics (operation system, store arrangement) on customers' perceived benefits and the effect of perceived benefits (convenience, speed, stability, playability) on revisit intention were verified. In addition, by using untact propensity as a control variable, the purpose of this study was to examine that the characteristics of unmanned convenience stores have a moderating effect on the perceived benefits of customers. Design/methodology/approach - The study collected 201 survey data from unmanned convenience stores in China. In order to analyze the data, Smart PLS was used to carry out empirical analysis. Findings - The results showed that operating systems had a positive impact on convenience, speed, and safety, while store layout had a positive impact on playfulness. Perceived benefits (convenience, safety, and playfulness) had a positive impact on their intention to revisit. Rapidity had a negative impact on the intention to revisit. Contactless tendencies regulate the effect of operating systems on convenience. Research implications or Originality - Unmanned convenience stores are striving to provide high-quality experiences to customers and increase customer satisfaction by utilizing cutting-edge IT technologies in stores such as AI, mobile device payment services, QR codes, and big data technologies. Recently, research on unmanned convenience stores has been active in the service and distribution industry-related fields, but research on the intention to revisit is insufficient. Also, few studies have used untact propensity as a control variable.

• Korean Journal of Applied Biomechanics
• /
• v.25 no.1
• /
• pp.11-19
• /
• 2015

Objective : The purpose of this study was to analyze the correlation between physical factors (X-factor, X-factor stretch) and club factors (club speed, ball speed, club path, smash factor, vertical launch angle, spin rate, flight time, total length) during impact and it affect on the total distance of the ball during a golf driver swing. Background : There were not enough studies that analyzed the correlation between physical factors(X-factor, X-factor stretch) and club factors(club speed, ball speed, club path, smash factor, launch angle, spin rate, flight time, total length) during a purpose swing to increase total distance. Method : For this study, 9 right handed professional male golfers (KPGA) were chosen. The test subject group used their own drivers and each took a total of 10 swings. These swings consisted of 5 purpose swings to increase total distance and 5 normal swings. Results : The purpose swing to increase total distance showed larger physical factors(X-factor, X-factor stretch) compared to a normal swing however the results were not statistically significant. Total distance increased during a purpose swing as a result of ball and club speed. Conclusion : The results showed that club factors, ball speed and club speed contributed the most in affecting the total distance of the ball during a purpose swing.

• Journal of the Society of Naval Architects of Korea
• /
• v.49 no.6
• /
• pp.478-483
• /
• 2012

The speed performances of ice sea trial on the Arctic(2010 & 2011) area were shown different results depend on the ice floe size. Penetration phenomena of level ice was not happened on medium ice floe and tore up by the impact force because the mass of medium ice floe is similar to the mass of Araon which is Korean ice breaking research vessel and did not shut up by the ice ridge or iceberg. The sea trial on the Amundsen sea was performed at the big floe which is classified by WMO(World Meteorological Organization). Three measurements of ice properties and five results of speed trial were obtained with different ice thicknesses and engine powers. To evaluate speed of level ice trial and model test results at the same ice thickness and engine power, the correction method of HSVA(Hamburg Ship Model Basin) was used. The thickness, snow effect, flexural strength and friction coefficient were corrected to compare the speed of sea trial. The analyzed speed at 1.03m thickness of big floe was 5.85 knots at 10MW power and it's 6.10 knots at 1.0m ice thickness and the same power. It's bigger than the results of level ice because big floe was also slightly tore up by the impact force of vessel based on the observation of recorded video.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2008.04a
• /
• pp.561-566
• /
• 2008

Recently, because of development of the high speed train technology, the vibration loads by train is significantly increased ever than before. This buried gas pipelines are exposed to both repeated impact loads, and, moreover, they have been influencing by vibration loads than pipeline which is not located under vehicle loads. The vibration characteristic of pipeline is examined by dynamic analysis, and variable is only train speed. Since an effect of magnitude of vibration loads is more critical than cover depth, as increasing the train speed, the vibration speed of buried pipelines is also increased. The slope of vibration velocity is changed by attenuation of wave, at train speed, 300 km/h. From the analysis results, the vibration velocity of pipelines is satisfied with the vibration velocity criteria which are established by Korea Gas Corporation. The results present operation condition of pipelines under rail loads has fully sound integrity based on KOGAS specification.