• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.582-587
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• 2002

Current information storage devices, such as HDD, CD/DVD-ROM/RW, probe-based memory and hologram memory, are compared with biological information storage mechanisms in DNA and brain memory. Newly developed approaches to overcome the limit of storage capacity are introduced in both magnetic and optical recording devices. Linear and areal density of information stored in the biological and mechanical storages are compared for the applications and developments of new storage devices.

• Journal of KSNVE
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• v.9 no.4
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• pp.693-702
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• 1999

We study the characteristics of airflow and sound noise induced by disk rotation in optical disk drives. The characteristics of airflow around a rotating disk surrounded by various tray structures are numerically investigated using a commercial CFD program and then compared with experimental results. Sound pressure and intensity caused by the fluid-structure interactions in the CD/DVD-ROM drive are measured, and the effect of the ariflow on the sound noise and disk vibration is discussed. In order to reduce airflow-induced noise and vibration around the rotating disk, tray geometry is modified. Both numerical and experimental studies implemented with different tray models show that the improved tray model alters the characteristics of the disk-induced airflow, causing the reduction of the airflow-induced sound level.

• Journal of Korean Library and Information Science Society
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• v.27
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• pp.137-169
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• 1997

The Annual Editions of SCI(Science Citation Index) CD-ROM over the last five years ('92-'96) were studied to investigate: 1) the status of domestic research activity in science & technology, in comparison with other countries, 2) research activity by universities and research institutes in Korea. Because the selection of journals in SCI is based on the criteria of citation sources, the journals registered in SCI are recognized as the Core Journals in each area of research. Therefore, the analysis result of SCI data is a quite reliable measurement to evaluate the research activities in science and technology. In 1996 a total of 6, 227 papers were listed on SCI, ranking the 21st up from the 29th in 1992. Over the last five years, the number had grown rapidly at an average of 29% per annum. This fast growth is expected to continue in the future.

• Journal of Korean Library and Information Science Society
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• v.33 no.4
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• pp.85-100
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• 2002

According to increase number of electronic publications, teacher ind student demand them in their teaching md teaming activities. So school libraries must provide various materials(ex : printed, audio-visual and electronic materials). The purpose of this study is to identify the use of electronic publications in school libraries md to suggest the methods of utilization of them.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.45-56
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• 2003

This study was conducted to develop user interface design guidelines for those who design education software products (web sites or CD-ROM titles). To establish this guideline scheme, international standards, commercial design guidelines, and research papers were surveyed. Especially, ISO 9241 was referred as a basic model of a guideline scheme. First, the research group developed draft guidelines. After that, education software developers, designers, and a user group reviewed the draft and the draft was revised with their commentations. Five components were selected as a primary class of guideline scheme: general principle, dialogue design, user guidance, visual interface, and information presentation. Each component was divided several components as a secondary class. Finally, 45 items were selected as user interface design guidelines for the education software design.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.47-54
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• 2009

Spin coaters are the essential instruments in micro-fabrication processes, which apply uniform thin films to flat substrates. In this research, a spin coater diagnosis system is developed to detect the abnormal operation of TFT-LCD process in real time. To facilitate the real-time data acquisition and analysis, the circular-buffered continuous data transfer and the short-time Fourier transform are applied to the fault diagnosis system. To determine whether the system condition is normal or not, a steady-state detection algorithm and a frequency spectrum comparison algorithm using confidence interval are newly devised. Since abnormal condition of a spin coater is rarely encountered, algorithm is tested on a CD-ROM drive and the developed program is verified by a function generator. Actual threshold values for the fault detection are tuned in a spin coater in process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.316.2-316
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• 2002

There are a lot of roots of errors in the motion of the optical pickup actuator being one of the most significant components in the CD-ROM drive. Most of the studies recently performed have a tendency to seek fur the causes from an actuator itself. We found the fact that the range of the natural frequencies of a feeding deck and an actuator is close each other through an experiment. This paper present the dynamic characteristics of an actuator affected by the motion of a feeding deck. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.360.1-360
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• 2002

Current information storage devices, such as HDD, CD/DVD-ROM/RW, probe-based memory and cabon nano tubes, are compared with biological information storage mechanisms in DNA and brain memory. Various biological components in living cells are analyzed based on "irreducible complexity" of intelligent design concept. Linear and arel density of information stored in the biological and mechanical storages are compared for the applications and developments of new storage devices.

• Journal of KSNVE
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• v.6 no.4
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• pp.521-528
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• 1996

Recently, higher speed optical disk drives including computer CD-ROM drives tend to be increasingly demanded to read or write the enormous volume of digital data. To this end, both structure and controller designs of the optical pick-ups should be improved concurrently. In this paper, the pick-up during auto-focusing motion is mathematically modelled retaining all its peculiar features. The model turns out a linear time invariant system suitable for a control design namedH${\infty}$ which ensures robust stability in the presence of system uncertainties. Numerical simulations are performed to demonstrate the robustness with appropriate performance specifications being satisfied. In addition, as the implementation issue of it, procedures of temporal discretization as well as model reduction of the controller are also addressed.

• Journal of Agricultural Extension & Community Development
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• v.8 no.1
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• pp.1-14
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• 2001

e-Learning has brought dramatic changes in education system for many companies in Korea. Many researchers and practitioners believe that e-Learning will be the main educational system for every companies in the world. e-Learning is an alternative education system, which includes computer based learning, web based learning, virtual classroom, and distance learning. e-learning has been expected to impact every educational sectors including Extension services. This study intends to identify and suggest some implications for successful e-Learning implementation of Extension education by investigating the successful factors of enterprises' e-Learning system, where outstanding results have be shown.