• Journal of Energy Engineering
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• v.22 no.3
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• pp.287-293
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• 2013

This study was carried out to diminish the formation of scale in boilers which is one of the defect elements when they are operating. The defect relating to scale can cause a fatal impact on the explosion of boilers due to the overheating of their tubes, or it can affect the flow of water inside boilers with its bad circulation and result in a disparity of water inside the equipment. Heat transfer in the scale is low comparing to the boiler material, so it can lead to energy losses and has also impact on the global warming. In 2005, the Korean government introduced a system which requires boiler users to install the equipment which can prevent or eliminate the formation of scale to improve the management of water quality in boilers. The study on the techniques for preventing or eliminating the formation of scale started in 1821 and since then subsequently there have been lots of similar studies. The first one was about the scale reduction using potato starch. Since an ultrasonic scale preventer developed by a scientist from a Russian acoustic institute was introduced in1993, a variety of equipment of this kind have been disseminated in Korea. There has been a need to demonstrate the condition for the best performances of such equipment. Boilers are mostly composed of the main body and 288 the tube with a circular curved surface. I carried out a demonstration study on a circular tube which affects the scale defect the most among the boiler components. As a result of it, I found out the fact that the ultrasonic wave needs to reach a certain level of sound pressure and frequency to affect the formation of scale.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.945-950
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• 2004

Surface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction.Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.17-24
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• 2004

Surrface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern using photolithography on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions from based on friction map. Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.188-193
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• 2005

Surface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions from based on friction map. Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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• pp.452-474
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• 2010

Formidable growth of Internet technologies has revealed challenging issues about its scale and performance evaluation. Modeling and simulation play a central role in the evaluation of the behavior and performance of the large-scale network systems. Large numbers of nodes affect simulation performance, simulation execution time and scalability in a weighty manner. Most of the existing simulators have numerous problems such as size, lack of system theoretic approach and complexity of modeled network. In this work, a scalable discrete-event modeling approach is described for studying networks' scalability and performance traits. Key fundamental attributes of Internet and its protocols are incorporated into a set of simulation models developed using the Discrete Event System Specification (DEVS) approach. Large-scale network models are simulated and evaluated to show the benefits of the developed network models and approaches.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.47-57
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• 1999

The small-scale models have been utilized for the prediction of inelastic behavior of reinforced concrete structures for several decades. The parameters that affect the similitude between the model and prototype are various. Among them, the effect of bond between the model reinforcement and the model concrete is one of the most important factors. The study reported herein is addressed to verifying this similitude in bond behavior. The simple beams which have the lap splice at the midspan were made and flexural tests were performed under two-point loading. The length of lap splice are varied from 0.4ld through 0.7ld and up to 1.0ld where ld is the development length of the reinforcement. The selected scales are 1/1, 1/5, 1/10 and 1/12. Two prototype specimens and three models were tested in addition to the associated material tests and the test results are compared from the viewpoint of similitude.

• International Journal of Contents
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• v.12 no.2
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• pp.6-11
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• 2016

We developed a pilot-job based large-scale distributed computing system to support HTC and MTC, called HTCaaS (High-Throughput Computing as a Service), which helps scientists solve large-scale scientific problems in areas such as pharmaceutical domains, high-energy physics, nuclear physics and bio science. Since most of these problems involve critical data that affect the national economy and activate basic industries, data privacy is a very important issue. In this paper, we implement a privacy enhanced data security mechanism to support HTC and MTC in a large-scale distributed computing system and show how this technique affects performance in our system. With this mechanism, users can securely store data in our system.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.64.3-65
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• 2020

It has been studied that galaxies evolve following a typical trajectory on the phase space under the influence of deep gravitational potential of galaxy clusters. Similarly, the large-scale filaments could also affect the evolution of galaxies before falling into the clusters. In this study, using a dark matter-only cosmological simulation, N-Cluster Run, we explore the evolution of galaxies on the phase space drien by large-scale filaments. We find that galaxies around the filaments form a common trajectory on the phase space as well as cluster galaxies do. We also examine how these trajectories change depending on various physical parameters such as galaxy mass, initial distance of galaxies from large-scale filaments, and cluster mass.

• Journal of Hospice and Palliative Care
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• v.15 no.2
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• pp.77-87
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• 2012

Purpose: This study investigated the effects that music therapy by self-selected music listening has on the affect and stress relief in adult patients who have been diagnosed with terminal cancer by pain level. Methods: Participants were 20 terminally ill cancer patients who were over 18 years old and were admitted to the hospice and palliative care unit of a local hospital. At the beginning of each session, participants selected music of their choice. Each participant had a total of six 30-minute music listening sessions. Participants were grouped into two according to their self-rated perceived pain scores on the visual analogue scale and numeric rated score: 5 and above and less than 5. Each participant completed a questionnaire on their affect state before and after each session and a questionnaire on their stress level before the first session and after the last session. Further analysis was performed to compare differences between the two groups according to pain level. Results: There were significant differences in patients' affect before and after each session (P<0.001) and stress level before and after the therapy (P=0.001). Conclusion: In this study, self-selected music listening had positive effects on terminal cancer patients' affect and stress regardless of perceived pain level. Therefore, self-selected music listening can be used as an appropriate intervention to improve affect and reduce stress in terminal cancer patients in the hospice and palliative care unit.

• Journal of Sasang Constitutional Medicine
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• v.26 no.2
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• pp.133-145
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• 2014

Objectives In this study, we tried to examine that Sasang Constitutional differences affect the direction of the treatment of anger by comparing the effect of mindfulness meditation for anger scale in accordance with the difference of the constitution. Methods We analysed 105 college student's Constitution by Questionnaire for the Sasang Constitution Classification II and the effect of mindfulness meditation for anger by State-Trait Anger Expression Inventory Korean version(STAXI-K), Korean Version of the Behavioral Anger Response Questionnaire(K-BARQ). Volunteers who participated in this study were 105 people, except for person that did not properly entered the anger scale and Questionnaire for the Sasang Constitution Classification II, the subjects of analysis for State-Trait Anger Expression Inventory Scale were 45 and for the Behavioral Anger Scale were 49. Results & Conclusions The result of the effects of mindfulness meditation according to Sasang Constitution was as follows. The tendency to try to disperse and avoid the anger was increased through meditation for all subjects. The diffusion of male subjects and the avoidance of female subjects was increased. The effect of meditation on anger did not differ according to Sasang Constitution, constitutional differences did not affect the effects of meditation. The tendency of avoidance of anger was increased in Soyangin, Anger-out was decreased and the tendency of avoidance and diffusion of anger were decreased in Taeeumin through meditation.