• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.165-170
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• 2019

Cancer cells are different from normal cells in terms of life cycle, behavior, and growth patterns. Cancer cells can migrate freely in the body through blood vessels and lymph nodes. The cancer cells easily interact with various substrates including extracellular matrix and vessels and they can differentiate in the new environment. However, it is not well known about the adhesion preference of cancer cells on the substrate and the mechanism of their interaction. In this study, we prepared the nano-, micro-patterned substrates using E-beam lithography techniques. MCF-7 cells were tested on the substrates to find out their adhesion preference. The substrates were made by polydimethylsiloxane (PDMS) with specific patterns including pillars with a diameter of 500 nm, 700 nm, $3{\mu}m$ and $5{\mu}m$. MCF-7 cells were seeded on the substrates and incubated for 24 hours. As a result, this study clearly demonstrated that the MCF-7 cells preferred 700 nm patterning.

• Elastomers and Composites
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• v.43 no.1
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• pp.8-17
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• 2008

Styrene-butadiene rubber(SBR) has good abrasion resistance, miscibility, and anti-vibration property. however, it is easily damaged by ozone and swelled by hydrocarbon fluids because of unsaturation part in main chain, that causes loss of visco-elasticity and reduction of product's life cycle. Therefore, object of this study is to cope with this problem. SBR is blended with various proportion of ethylene-propylene-diene terpolymer(EPDM), which has excellent ozone and oxygen resistance, to improve physical properties and ozone resistance, and diverse analytical techniques are used to measure morphology, glass transition temperature$(T_g)$, ozone-resistance, degradation temperature, static spring constant, hardness for considering a suitability for anti-vibration industrial product. We found that the blend consisting of SBR 70% and EPDM 30% showed no crack after ozone test and good miscibility between SBR and EPDM from this study.

• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.41-49
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• 2021

Domestic maintenance strategies are shifting from safety assessment to performance assessment, and related systems and laws are being restructured to meet those criteria. In order to introduce asset management based on performance evaluation, related evaluation methods such as performance measures and level of service should be made to evaluate performance according to the characteristics of the structure, but these are not well-prepared in Korea. In this study, we present a computerized model and system for implementing asset management that introduces techniques such as performance evaluation, life cycle cost analysis, performance measures, and level of service in conjunction with existing maintenance and safety diagnosis procedures. The features of this system consist of three modules to enable separate operations of existing maintenance, safety management and asset management. The system is designed to be used as a reference for public institutions to introduce asset management in the future.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.78-84
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• 2020

The F&EI technique is one of the risk assessments with many advantages. It can save time and effort compared to quantitative risk assessment (QRA). By using the evaluation result of this technique, it is possible to check the effectiveness of the investment cost. In addition, a relative risk ranking can be created and used to establish the facility management cycle and to prioritize investment. However, evaluating the target process can be evaluated more than the actual risk since the LCCF, a loss prevention measure, is too limited. In addition, calculating premiums via this method can result in excessive premiums, making it difficult to evaluate the risk precisely. Therefore, new safety guard was added to the LCCF of the F&EI risk assessment with reference to HAZOP and LOPA techniques. Newly added LCCFs are Deflagration arrester, Check valve, SIS, and Vacuum beaker, etc. As a case study, F&EI risk assessment was performed on Acetone storage tank of a API (Active pharmaceutical ingredient) plant to compare actual MPPD. The estimated loss amount was 592,558$ for the existing technique and 563,571$ for the improved technique, which was reduced by about 5% compared to the previous one.This proved that a more precise evaluation is possible and that the efforts for safety at the workplace are reflected in the evaluation results.

• Journal of People, Plants, and Environment
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• v.23 no.3
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• pp.347-362
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• 2020

Background and objective: It is difficult to conclusively determine the exact cause of tree defects since multiple causes are involved such as climate change, plantation, tree quality and planting time, construction, planting base, drainage, sunshine conditions, maintenance, and microclimate. The data related to landscaping construction defects are scattered or fragmented by companies and years, but not managed systematically by the defect information management system. Most of the earlier studies associated with tree defects in apartment complexes suggested defect rates after examining tree defects in the completed construction site and proposed fragmentary and subjective conclusions about the causes of defects observed in trees with high defect rates. It is proposed to continue to conduct studies on the establishment and analysis of systematic databases to identify the exact causes of tree defects and measures to improve, and the need to accumulate systematic data in the construction process where many defects arises. This study was conducted to reduce the defects of trees planted in apartment complexes. Methods: Main factors related to tree defects were subdivided based on the results of literature review and a defect investigation at the completion site, and tree history management items were selected and subdivided during the construction stage. Results: The criteria for the preparation of subdivided items were obtained, and the tree history management checklist was written for the site under actual construction and a systematic database was established. Items that are categorized based to the causes of defects include the location of nurseries, date, tree quality, site conditions, planting techniques, microclimates, and maintenance. Conclusion: This study suggested tree history management items based on the tree defects that can be identified at the construction stage and applied them to the selected study site, which differentiates this study from earlier studies. It will be necessary to conduct a comprehensive and objective time series analysis on tree defects that occur over time by continuously monitoring and collecting data after construction.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.81-89
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• 2010

Recent modeling and simulation technology is being used in various fields. Especially in the field of military, Simulation-Based Acquisition (SBA) is recognized as a essential policy. To effectively carry out SBA, modeling and simulation techniques should be applied in the whole life-cycle for the weapon system development, and simulation architecture framework which provides easily reusable and interoperability is needed. Through reusability and interoperability, the costs of constructing the integrated collaborate environment for simulation based acquisition can be minimized. In this study, we define requirements, issues for enhancing reusability and interoperability, and propose simulation framework as a solution of the problem including structural design. Proposing simulation framework provides common functions for producing simulator as reusable units and easily changeable structure on user's purpose. In addition, we provide the result for applying simulation framework to our project.

• Korean Journal of Construction Engineering and Management
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• v.15 no.1
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• pp.122-133
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• 2014

Recent diversification of project delivery systems coupled with increasing mega-projects requires highly advanced construction management techniques. Among those techniques, procurement and design management are recognized as being the first priority for overseas construction projects. Nevertheless, previous research in design management has been limited to the quality management of the design documents at design stage. Therefore, it is necessary to explore the design management from a comprehensive perspective throughout the project life cycle. In this context, the purpose of this paper is to propose a conceptual framework for integrated design management (IDM). Several different concepts in relation to design management were investigated first in order to identify the major variables of the IDM framework. A comprehensive comparison of construction management methodologies was also analyzed in order to identify key factors of IDM. Finally, an IDM framework was proposed by combining those factors and relevant issues. Based on the proposed framework, a survey was conducted in order to validate the framework as well as to identity important areas for improving competitive capability of Korean construction companies.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.215-224
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• 2012

This study performs an exploratory investigation of the needs of the customers who use academic information service from a research institute, K, that provides information services for domestic academic institutions of natural science and technology. K institute is planning customized services in order to improve customer satisfaction on the academic information service And therefore, the institute begins the research on customer needs analysis and customer segmentation. The research is regarded as well-timed, because CRM implementation in public organizations has been activated recently. Data mining and data warehousing techniques were used for pilot analyses. For the purpose of customer segmentation, a mixed segmentation model, which adds product life cycle concept to the 'balanced customer segmentation' model, which in turn considers the value of customers from the organizational viewpoint and the value of organizations from the customer's viewpoint, simultaneously, was applied. The result of investigation indicated that, in the case of K, 'balanced customer segmentation' and 'contents reach approach' which uses data warehouse/OLAP, rather than those customer segmentation techniques that are often used within the industry, are the more potent ways of approach. This exploratory case study is expected to provide a useful guideline for 'deriving an organizationally unique CRM model' that recently is one of the hot topics in the CRM area.

• Journal of the Korean Electrochemical Society
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• v.24 no.4
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• pp.77-92
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• 2021

The energy density of lithium-ion batteries (LIBs) determines the mileage of electric vehicles. For increasing the energy density of LIBs, it is necessary to develop high-capacity active materials that can store more lithium ions within constrained weight. The rapid progress made in cathode technology has realized the utilization of the near-theoretical capacity of cathode materials. In contrast, commercial LIBs have still exploited graphite as active material in anodes since the 1990s. The most promising way to increase anodes' capacity is to mix high-capacity and long-cycle-life silicon oxides (SiOx) with graphite. However, the low initial Coulombic efficiency (ICE) of SiOx limits its content below 15 wt%, impeding the capacity increase in anodes. To address this issue, various prelithiation techniques have been proposed, which can improve the ICE of high-capacity anode materials. In this review paper, we introduce the principles and expected effects of prelithiation techniques reported so far. According to the reaction mechanisms, the strategies are categorized. Mainly, we focus on the recent progress of solution-based chemical prelithiation methods with commercial viability, of which lithiation reaction occurs homogeneously at liquid-solid interfaces. We believe that developing a cost-effective and mass-scalable prelithiation process holds the key to dominating the anode market for next-generation LIBs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3472-3480
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• 2010

The Clustering technology of Energy efficiency wireless sensor network gets the energy efficiency by reducing the number of communication between sensor nodes and sink node. In this paper, First analyzed on the clustering technique of the distributed clustering protocol routing scheme LEACH (Low Energy Adaptive Clustering Hierarchy) and HEED (Hybrid, Energy-Efficient Distributed Clustering Approach), and based on this, new energy-efficient clustering technique is proposed for the cause the maximum delay of dead nodes and to increase the lifetime of the network. In the proposed method, the cluster head is elect the optimal efficiency node based on the residual energy information of each member node and located information between sink node and cluster node, and elected a node in the cluster head since the data transfer process from the data been sent to the sink node to form a network by sending the energy consumption of individual nodes evenly to increase the network's entire life is the purpose of this study. To verify the performance of the proposed method through simulation and compared with existing clustering techniques. As a result, compared to the existing method of the network life cycle is approximately 5-10% improvement could be confirmed.