• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.203-204
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• 2010

In this study, We synthesized new generation of superplasticizer(SP) which show a shrinkage reducing effect as well as water reducing effect with adequate slump retention in a wide range of water cement ratio by introduction a shrinkage-reducing group into the molecular structure. To investigate effects of the SRS on the hydration of cement, DSC have been analysed. Also the general and shrinkage properties of the concrete were evaluated.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.5
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• pp.511-518
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• 2015

As the cost-per-byte of SSDs dramatically decreases, the introduction of SSDs to Hadoop becomes an attractive choice for high performance data processing. In this paper the cost-per-performance of SSD-based Hadoop cluster (SSD-Hadoop) and HDD-based Hadoop cluster (HDD-Hadoop) are evaluated. For this, we propose a MapReduce performance model using queuing network to simulate the execution time of MapReduce job with varying cluster size. To achieve an accurate model, the execution time distribution of MapReduce job is carefully profiled. The developed model can precisely predict the execution time of MapReduce jobs with less than 7% difference for most cases. It is also found that SSD-Hadoop is 20% more cost efficient than HDD-Hadoop because SSD-Hadoop needs a smaller number of nodes than HDD-Hadoop to achieve a comparable performance, according to the results of simulation with varying the number of cluster nodes.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.310-320
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• 2010

In this study, factors affecting the development of new products and research about the relevance of the factors based on the research model was configured. Existing research and technology commercialization process of discrimination that occur in the importance of risk management and open innovation company's competitive advantage in new product development and affect the reporter know what the effect is used as a control variable effects. Factor in the development of new products through research and innovation capacity and knowledge management activities, the introduction of open innovation and enterprise level ever due to the level of risk management controls and the need for effective research to study the model was proposed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1248-1253
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• 2007

Urban transit or subway stations generally service for a long period of several decades. And, the urban transit or subway is public transportation which lots of people takes every day. During the service time, they are inevitably damaged from environmental corrosion, material aging, fatigue, and the coupling effects with long-term loads and extreme loads. The included damage accumulates and performance degenerates due to the above factors. They would inevitably reduce the resisting capacity of station against the disaster; even they result in collapse with the structural failure under extreme loads. And, if disaster such as earthquake, fire, etc. happens, it causes huge property damage and threatens the human lives. Because of these above reasons, the intelligent health surveillance system should be researched and developed for ensuring the safety of station. In this paper, the research plans of the intelligent health surveillance system of urban transit station are presented. And also, the development or establishment directions of this system are suggested.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.188-191
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• 1997

In the recent sheet metal forming simulations, it increases to adopt the dynamic explicit method for an effective computation and the elastic-plastic formulation for stress recovery. It is inevitable in the dynamic explicit method that some noises occur and sometimes partly spoil results of simulations. It is severer when complicated contact conditions are included in simulations. An effective method to control these noises is introduction of damping effects. In this paper, the concept of contact damping is introduced in order to suppress noises due to complicated contact conditions. This is checked by analyzing a simple sheet metal forming process(U-bending). From the computational results, it is shown that the contact damping can effectively control the noises due to contacts and develop more reliable internal stress states.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.22-26
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• 2003

Electrical conductivity of the oxidized MWNT(Multi walled nanotubes)/polymer composites were investigated with respect to various oxidative conditions of acid concentration, treatment temperature, and treatment time. To remove the impurities existing in MWNT-deposites, liquid-phase oxidation was performed using the $HNO_3/HSO_4$ mixtures. Secondary effects occurred by the oxidation of MWNTs such as the damages of MWNTs and the introduction of functionalities were analyzed through measuring FT-IR, TEM, and zeta potential, All the oxidized NWNTs were functionalized with carboxylic groups and the conditions of oxidation of the MWNTs could have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT. The electrical properties of MWNT composites strongly depend on the oxidative conditions of MWNTs. The conductivity of the composites filled with the proper oxidized MWNT showed the highest percolation threshold.

• Journal of Yeungnam Medical Science
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• v.23 no.2
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• pp.143-151
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• 2006

In the past decade, the median duration of survival among patients with advanced colorectal cancer has increased from 12 months to about 18 months, primarily as a results of the introduction of irinotecan and oxaliplatin. Advances in the understanding of the molecular mechanisms underlying the development and progression of cancer have resulted in the discovery of new therapeutic interventions that target specific molecular abnormalities. Their specificity, and therefore their potential to bind preferentially and modify tumor-specific targets, sparing normal tissues and causing fewer side-effects compared to conventional cytotoxic agents, makes them an attractive therapeutic option. The future of this approach for the treatment of solid tumors is promising.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.371-376
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• 1999

Stick-slip friction is present to some degree in almost all actuators and mechanisms and is often responsible for performance limitations. Simulation of stick-slip friction is difficult because of strongly nonlinear behavior in the vicinity of zero velocity. A straightforward method for representing and simulating friction effects is presented. True zero velocity sticking is represented without equation reformulation or the introduction of numerical stiffness problems. Stick-slip motion is investigated experimentally, and the fundamental characteristics of the stick-slip motion are clarified. Based on these experimental results, the characteristics of static in the period of stick and kinetic friction in the period of slip are studied concretely so as to clarify the stick-slip process.

• International Commerce and Information Review
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• v.12 no.4
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• pp.25-45
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• 2010

The objective of this paper is to review the mechanics of how global e-trade practices can affect a firm's performance. It is well known that the introduction of global e-trade systems can save transaction costs at the macro level. However this study is extended at micro level by determining whether global trade transaction costs influence positively or negatively in exporting firms performances at firm level. A theoretical framework is suggested for determining the usage and performance of global e-trade with the global e-trade barriers. An empirical analysis of South Korean exporting firms has been undertaken. This paper concludes that the global e-trade has yet to overcome the barriers resulting from the transaction costs and asset specificity. In this regard, appropriate action like intensive education and training program should be implemented in order to make South Korea's global e-trade more matured.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.530-536
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• 2000

In this paper, the influence of several factors such as hardness, internal defect and non-propagating crack on fatigue limits was investigated with three kinds of ductile iron specimens. From the experimental results the fatigue limits were examined in relation with hardness and tensile strength in case of high strength specimens under austempering treatment; in consequence the marked improvement of fatigue limits were not showed. The maximum defect size was an important factor to predict and to evaluate the fatigue limits of ductile irons. And, the quantitative relationship between the fatigue limits$({\sigma}_w)$ and the maximum defect sizes $(\sqrt{area}_{max})$ was expressed as ${\sigma}_w^n{\cdot}{\sqrt{area}}_{max}=C_2$. Also, it was possible to explain the difference for the fatigue limits in three ductile irons by introduction of the non-propagating crack rates.