• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.898-901
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• 2003

In order to get the drive reliability and low Power-consumption characteristics, most of small form factor HDD has und the load/unload mechanism instead of CSS type. Compared with CSS mechanism, the load/unload system has little opportunity of head/media contact during the disk spin-up and down. However, the load/unload mechanism needs the precise integration technology with slider, suspension, ramp and load/unload velocity, and all of these component s should be designed simultaneously, not an individually. In this paper, we focus the design of the suspension stiffness using the specified ABS design. We use the CML software to calculate the load/unload dynamic and use the RSM(Response surface method) to get the optimal condition of the suspension stiffness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.902-905
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• 2003

It's general a trend to use the load/unload mechanism in the small form factor HDD, like 2.5", 1.8" and 1.0". The load/unload mechanism has tittle opportunity of head/media contact during the disk spin-up and down. However, the load/unload mechanism needs the precise integration technology with slider, suspension ramp, load/unload velocity and so on, and all of these components should be designed simultaneously, not an individually. In this paper, we measured the load/unload velocity in the drive level, and executed the load/unload dynamics with this velocity profiles. We could find the current load/unload mechanism suitable to the long load/unload test.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.210-214
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• 2005

The purpose of this paper is to study the effects of the flexibility of HDD base plates on spindle vibration via theoretical predictions and experimental measurements. The flexibility of the base plate can significantly affect HDD spindle vibration. This is the most prominent feature in 2.5 inch HDD. Nevertheless, theoretical analysis of the spindle vibration often neglects the flexibility of the non-rotating part including spindle, base plate, and top cover. Our theoretical model developed in University of Washington can include the flexibilities of spindle and base plate. As a result, our theoretical prediction generally agrees well with our experimental measurements in vibration analysis. Moreover, Because of its small form factor, industrial practice is to use flanged disks instead of regular disks in vibration testing of prototypes. Our experimental measurements indicate that flanged disks and regular disks have very different behavior when the frequency is above 1 KHz.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.284-285
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• 2004

We have developed a 10 Gbps receiver consist of an InGaAs PIN PD and an embedded TIA(transimpedance preamplifier). The receiver is assembled in a small form factor (SFF) Package. It shows f-3dB of 10 GHz and the sensitivity more than -20 dBm at 10$^{-10}$ BER (bit-error-rate) for 10 Gbps optical input signal of 2$^{31}$-1 PRBS (pseudo-random-bit-sequence).

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2071-2081
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• 1995

In order to examine the effects of yield stress, tensile strength and thickness on the buckling behavior during bending of pipes, the nonlinear finite element analysis of the 3-point bending tests was carried out using the commercial software (ABAQUS) under the condition of L4(2$^{3}$) performed according to the designed condition. Form the analysis of simulation results, it was found that yield stress and thickness were the major factors on buckling load at pipe bending and tensile strength gave little influence because the plastic strain and plastic zone are small. For the punch displacement to the occurrence of buckling, thickness is a major factor and yield stress and tensile strength are the minor factors.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.15-25
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• 2016

Purpose: The purpose of this study is to identify the success factor of local food markets compared to other types of markets such as large discount stores. Methods: SWOT analysis was conducted. In addition to the analysis, we also have interviewed the local farmers and retailers to elaborate the analysis results. Results: The study shows the success factors to the local markets are minimizing the stages of distribution channels, shortening the travel distance from producers to consumers, providing fresh foods, maintaining small amount of production system, and supporting customers. Conclusion: Customer satisfaction is one of the key factors for the successful growth of local food markets. It is strongly recommend to find strategic ways of meeting customer needs since the local food markets are facing tough competition form the large retail stores armed with huge amount of capitals and infrastructures.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.425-426
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• 2008

The Panda-type polarization maintaining fibers were fabricated by VAD(vapor-phase axial deposition) method. We fabricate Panda style polarization maintaining fibers that have small form factor($80{\mu}m$), high H-parameter of about $1{\times}10^{-4}/m$ and low optical loss of about 3dB/km.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.23-34
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• 2013

Over the past several decades in the microelectronics industry, devices have gotten smaller, thinner, and lighter, without any accompanying degradation in quality, performance, and reliability. One permanent and deniable trend in packaging as well as wafer fabrication industry is system integration. The proliferating options for system integration, recently, are driving change across the overall semiconductor industry, requiring more investment in developing, ramping and supporting new die-, wafer- and board-level solution. The trend toward 3D system integration and miniaturization in a small form factor has accelerated even more with the introduction of smartphones and tablets. In this paper, the key issues and state of the art for system integration in the packaging process are introduced, especially, focusing on ease transition to next generation packaging technologies like through silicon via (TSV), 3D wafer-level fan-out (WLFO), and chip-on-chip interconnection. In addition, effective solutions like fine pitch copper pillar and MEMS packaing of both advanced and legacy products are described with several examples.

• Journal of Power Electronics
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• v.14 no.4
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• pp.632-640
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• 2014

For low-power high-frequency LED driver applications in small form factor mobile products, a high-efficiency boundary conduction mode tapped-inductor boost converter is proposed. In the proposed converter, the switch and the diode achieve soft-switching, the diode reverse-recovery is alleviated, and the switching frequency is very insensitive to output voltage variations. The circuit is quantitatively characterized, and the design guidelines are presented. Experimental results from an LED backlight driver prototype for a 14 inch notebook computer are also presented.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.111-116
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• 2006

The purpose of this paper is to study the effects of the flexibility of HDD base plates on spindle vibration via theoretical predictions and experimental measurements. The flexibility of the base plate can significantly affect HDD spindle vibration. This is the most prominent feature in 2.5 inch HDD. Nevertheless, theoretical analysis of the spindle vibration often neglects the flexibility of the non-rotating part including spindle, base plate, and top cover. Our theoretical model developed in University of Washington can include the flexibilities of spindle and base plate. As a result, our theoretical prediction generally agrees well with our experimental measurements in vibration analysis. Moreover, because of its small form factor, industrial practice is to use flanged disks instead of regular disks in vibration testing of prototypes. Our experimental measurements indicate that flanged disks and regular disks have very different behavior when the frequency is above 1 KHz.