• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.359-360
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• 2008

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.200-206
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• 2003

Identification method is formulated to evaluate the dynamic characteristics of air bearings under NFR (Near Field Recording) sliders. Using dynamic analysis, impulse responses and frequency response functions of NFR sliders are obtained on numerical non-linear models including rigid motion of slider and fluid motion of air bearing under the slider. System parameters are identified by modal analysis method and instrumental variable method. The identified system parameters of sliders are utilized to evaluate the dynamic characteristics of air bearings.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.193-198
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• 2000

Near-field recording NFR), advanced optical storage technology, relies on maintaining a small gap between the optical head and the media. This can be accomplished by utilizing the flying optical head concept as in the magnetic recording. In this research, slider/suspension system and plastic disk are tested for their head/disk interface performance. CSS tests are conducted to monitor the frictional and flying characteristics of sliders.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.1
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• pp.45-58
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• 2007

This study aims to examine the effects on nociceptive neuron excitability by application of electroacupuncture and Meloxicam gel in rat with inflammation. It used 24 rats for experiment, divided them into control group, electroacupuncture group(EA group), Meloxicam group(ME group), combination of electroacupuncture with Meloxicam group(EA+ME group), caused hyperalgesia by injecting ${\lambda}$-carrageenan into hindpaw and conducted treatment three times for experimental period. Noxious flexion withdrawal reflex(NFR) and somatosensory evoked potential(SEP) were measured immediately after induction, at 24 hours, 48 hours and 72 hours after induction. Change of NFR(reaction time, RMS) showed no significant differences among EA group, Meloxicam group, and EA+Meloxicam group, but all treatment groups showed significant differences compared to control group from 48 hours. In NFR threshold, there were significant differences between EA+Meloxicam and other groups. In SEP amplitude, there were significant differences between EA+Meloxicam and control group from 48 hours. This study showed that EA+Meloxicam gel had an effect on nociceptive neurone excitability. Therefore, it is considered that appropriate combination of anti-inflammatory drug with electroacupuncture for pain control will be very desirable.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.785-790
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• 2003

This paper presents an approach to optimally design the air-hearing surface (ABS) of the optical flying head for near-field recording technology (NFR) NFR is an optical recording technology using very small beam spot size by overcoming the limit of beam diffraction. One of the most important problems in NFR Is a head disk interface (HDI) issue over the recording band during the operation. A multi-criteria optimization problem is formulated to enhance the flying performances over the entire recording band during the steady state. The optimal solution of the slider, whose target flying height is 50 nm, is automatically obtained. The flying height during the steady state operation becomes closer to the target values than those for the Initial one. The pitch and roll angles are also kept within suitable ranges over the recording band. Especially. all of the all-hearing stiffness are drastically increased by the optimized geometry of the air hearing surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.748-753
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• 2000

Nowadays, many studies and researches in data storage have been carried out and storage capacity is increased. But the limitation of storage capacity is happened for several problems. One of them is spot & pit size in optical and magnetic data storage and another is the resolution of actuators. The problems in spot & pit size is covered by new data storage methods- for example, NFR{Near-Field Recoding) system. But the resolution limit of an actuator doesn't follow up the development of spot & pit size. Because of them, we should improve a resolution of an actuator. Especially, in this paper an actuator is studied and designed for NFR(in using SIL(Solid Immersion Lens) system. It is a dual stage actuator, which consists of a Fine actuator and a Coarse actuator, and should desire 100nm accuracy. But, our actuator system only includes tracking mechanism execpt focusing mechanism which is controlled by slider mechanism used in HDD. Its actuating force generation method is VCM(Voice Coil Motor). The Fine actuator is composed of 4-leaf springs and a bobbin wrapped by coil. The Coarse actuator has Coils and 3-Roller bearings.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.65-75
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• 2019

Non-Functional Requirements (NFR) play a crucial role during the software development process. Currently, NFRs are considered more important than Functional Requirements and can determine the success of a software system. NFRs can be very complicated to understand due to their subjective manner and especially their conflicting nature. Self-adaptive systems (SAS) are operating in dynamically changing environment. Furthermore, the configuration of the SAS systems is dynamically changing according to the current systems context. This means that the configuration that manages the trade-off between NFRs in this context may not be suitable in another. This is because the NFRs satisfaction is based on a per-context basis. Therefore, one context configuration to satisfy one NFR may produce a conflict with another NFR. Furthermore, current approaches managing Non-Functional Requirements trade-off stops managing them during the system runtime which of concern. To solve this, we propose fragmentizing the NFRs and their alternative solutions in form of Multi-entity Bayesian network fragments. Consequently, when changes occur, our system creates a situation specific Bayesian network to measure the impact of the system's conditions and environmental changes on the NFRs satisfaction. Moreover, it dynamically decides which alternative solution is suitable for the current situation.

• Transactions of the Society of Information Storage Systems
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• v.4 no.1
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• pp.19-22
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• 2008

For the assembly and evaluation of solid immersion lens (SIL) optical head which is the key component of SIL based near field recording (NFR) technology, we modify the Twyman-Green interferometer. Super-hemisphere SIL optical head for the surface recording is assembled and evaluated by the modified Twyman-Green interferometer. In order to verify the optical performance of the assembled SIL optical head, we compare the measured results of the SIL optical head with the simulation ones. Finally, we show the feasibility of applying the assembled SIL optical head to near field recording system by the experiment of the dynamic gap control based on test bed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.3
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• pp.164-171
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• 2003

Dynamic analysis using impulse responses is formulated to estimate effect of slider rail shape on dynamic responses in near-field optical recording drive. Impulse responses are obtained on numerical nonlinear model including rigid motion of a slider and fluid motion of an air bearing under the slider. Dynamic characteristics of slider motion are evaluated by utilizing the decay ratio of impulse responses and modal frequencies from frequency response functions. The dynamic characteristics of the designed NFR slider are checked by comparing those of a HDD slider(Nutcracker). Also, sensitivities of slider Position conditions and rotation speed on the dynamic characteristics are investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1028-1030
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• 2007

Mutual compensating concept between SIL(Solid Immersion Lens) and OL(Objective Lens) of NFR(Near Field Recording) is proposed, designed and manufactured to achieve a high NA and obtain a wider manufacturing tolerance. Tolerance information is present in article. An effective NA of Advanced SIL is 1.7 and adjustment between OL and SIL is carried out using our interferometer. We measured very clear RF signal using 3-axis actuator at Test bed.