• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.387-399
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• 2015

Recently collaboration network is generated to find out experts in their field as potential collaborators in health care sector. In this paper, the co-author network of a National Cancer Center researcher was generated for identifying each researcher's role and collaborative research pattern. The co-author network of 2,437 authors was extracted from 1,194 SCI(E) publications from 2000 to 2010 and author's role was analyzed by author's centrality value. Centrality reflecting only the number of papers and centrality weighted by the paper number, impact factor, and authorship contribution was evaluated. On the comparison with simple degree centrality value and the weighted degree centrality, difference of value was statistically significant(t=11.66, p=0.00). Co-author network considering various variables of the paper provides more objective figure of researcher's role. This suggests that co-author network could be more effective in identifying potential collaborators.

• Resources Recycling
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• v.23 no.5
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• pp.68-79
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• 2014

Since 1990s, efforts to recycle the waste plastics by chemical methods have increased. And in accordance with this trend, attempts have become active to use the waste PET as raw materials of chemical industries. In this article, the patents and papers for development of commercial technology for feedstock recycling and high end products from PET wastes were collected and analyzed. The open patents of USA (US), European Union (EP), Japan (JP), and Korea (KR) and SCI journals from 1974 to 2013 were investigated. The patents and papers were collected using key-words and filtered by the definition of the technology. The patents and papers were analyzed by the years, countries, companies, and technologies and the technical trends were discussed in this paper.

• Resources Recycling
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• v.23 no.3
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• pp.71-77
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• 2014

It is believed to have the international competitiveness of the domestic petrochemical in conjunction with the production of high value-added new product and variety of application by supercritical fluid process and the reaction of infusible/insoluble plastic wastes recycling. In this article, the patents and papers for the recycling of organic residues from the plastic wastes using supercritical fluids were collected and analyzed. The open patents of USA (US), European Union (EP), Japan (JP), and Korea (KR) and SCI journals from 1993 to 2012 were investigated. The patents and journals were collected using key-words and filtered by the definition of the technology. The patents and journals were analyzed by the years, countries, companies, and technologies and the technical trends were discussed in this paper.

• Resources Recycling
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• v.22 no.5
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• pp.63-70
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• 2013

There are generated the hundreds of tons of waste electric wire per year due to replace for increase transmission capacity and/or replacement of old electric wire by Korea's national power grid and/or private industrial factories. Recently, the wire recycling technologies studied extensively in terms of effieiency by of economic aspects and environment aspects. In this paper, the patents and papers for the recycling technologies of spent electric wire were collected and analyzed. The range of search was limited in the open patents of USA (US), European Union (EP), Japan (JP), Korea (KR) and SCI journals from 1975 to 2011. Patents and journals were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journals were analyzed by the years, countries, companies, and technologies.

• Corrosion Science and Technology
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• v.6 no.4
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• pp.154-158
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• 2007

For the application of flexible printed circuit board (FPCB), electroplated copper is required to have low surface roughness and residual stress. In the paper, the effects of surface roughness and residual stress of electroplated copper as thick as $8{\mu}m$ were studied on organic additives such as inhibitor, leveler and accelerator. Polyimide film coated with sputtered copper was used as a substrate. Surface roughness and surface morphology were measured by 3D-laser surface analysis and FESEM, respectively. Residual stress was calculated by Stoney's equation after measuring radius curvature of specimen. The addition of additives except high concentration of accelerator in the electrolyte decreased surface roughness of electroplated copper film. Such a tendency was explained by the function of additives among which the inhibitor and the leveler inhibit electroplating on a whole surface and prolusions, respectively. The accelerator plays a role in accelerating the electroplating in valley parts. The inhibitors and the leveler increased residual stress, whereas the accelerator decreased it. It was thought to be related with entrapped additives on electroplated copper film rather than the preferred orientation of electroplated copper film. The reason why additives lead to residual stress remains for the future work.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.705-713
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• 2014

In this paper, we propose a novel velocity ripple controller using phase compensation feedforward control. Velocity ripples result in many kinds of performance degradations in manufacturing machines, especially such as ultra-precision roll lathes. The generation of velocity ripple in constant velocity control comes from various causes, such as electrical torque ripples, mechanical worn out, inconsistent mass center, etc. Conventional researches about ripple is mainly for reducing torque ripple in actuator level, which is only one of reasons for velocity ripples, so in this study, we focus on eliminating velocity ripples in upper level controller using phase compensation feedforward controller. The proposed algorithm is composed of several modules, such as ripple extractor, phase adjuster and phase follower etc. The suggested algorithm can be easily extended, and it shows a superior performance in the experiments of ultra-precision roll lathes.

• Korean Management Science Review
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• v.23 no.3
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• pp.77-93
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• 2006

In the highly competitive world, there has been a concomitant increase in the need for the research and planning methodology, which can perform an advanced assessment of technological opportunities and an early Perception of threats and possibilities of the emerging technology according to the nation's economic and social status. This research is aiming to provide indicators and visualization methods to measure the latest research trend and aspect underlying scientific and technological documents to researchers and policy planners using 'Co-word Analysis' Organic light emitting diodes(OLED) is an emerging technology in various fields of display and which has a highly prospective market value. In this paper, we presented an analysis on OLED. Co-word analysis was employed to reveal patterns and trends in the OLED fields by measuring the association strength of terms representatives of relevant publications or other texts produced in the OLED field. Data were collected from SCI and the critical keywords could De extracted from the author keywords. These extracted keywords were further standardized. In order to trace the dynamic changes in the OLED field, we presented a variety of technology mapping. The results showed that the OLED field has some established research theme and also rapidly transforms to embrace new themes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5616-5630
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• 2019

Fully homomorphic encryption allows a third-party to perform arbitrary computation over encrypted data and is especially suitable for secure outsourced computation. This paper investigates secure outsourced computation of multiple matrix multiplication based on fully homomorphic encryption. Our work significantly improves the latest Mishra et al.'s work. We improve Mishra et al.'s matrix encoding method by introducing a column-order matrix encoding method which requires smaller parameter. This enables us to develop a binary multiplication method for multiple matrix multiplication, which multiplies pairwise two adjacent matrices in the tree structure instead of Mishra et al.'s sequential matrix multiplication from left to right. The binary multiplication method results in a logarithmic-depth circuit, thus is much more efficient than the sequential matrix multiplication method with linear-depth circuit. Experimental results show that for the product of ten 32×32 (64×64) square matrices our method takes only several thousand seconds while Mishra et al.'s method will take about tens of thousands of years which is astonishingly impractical. In addition, we further generalize our result from square matrix to non-square matrix. Experimental results show that the binary multiplication method and the classical dynamic programming method have a similar performance for ten non-square matrices multiplication.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.90-97
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• 2014

Context-aware systems provide proper services for the user according to current contexts. However, it is not actively deployed in our daily lives as expected, due to many concerns including occurrences of exceptions. C++/C#/JAVA provide exception handling facilities for desktop computing programs, but context-aware system developers might feel far more difficult to make use of such general facilities, because it is hard to decide the timing and position of exception handling with various devices engaged. In this paper, we propose an exception detection and handling mechanism using device semantics and AspectJ so that it can constantly detect a large number of devices to allow the programmers to detect and handle exceptions with less burden.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.960-963
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• 2001

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, another method of magnetic abrasive machining in which the N and S magnetic poles are vibrated and a workpiece is rotated only is tried in a non-ferromagnetic pipe(SUS304), and its finishing characteristics is experimental results, it is found that the vibration effects of magnetic poles on the finishing characteristics are large in internal finishing.