• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.15-18
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• 1990

In this paper, perpendicular magnetic recording system which consists of a single pole head and a double, layer medium is analyzed by using 2D-finite element simulation and Preisach model for describing hysteresis characteristics. For confirming this method, we compare the calculated magnetic field intensity which is above the isolated transition of magnetization and scale up experimental data which have already published. The results show a good agreement and we can conclude that this method is very useful to analyze perpendicular magnetic recording system.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.411-412
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• 2006

Photopolymers have been of considerable due to their easy of processing and high sensitivity. Exposure of photopolymers to optical source produce recroding mark where the light initiates a photoreaction that occurs preferentially in regions of high illumination. The photoreaction typically involves polymerization of an acrylic or epoxy monomer dispersed together with a photoinitiators in a polymeric binder. A number of photopolymerizable materials have been developed to apply them in 3D optical recording such as holographic or 3-dimensional data storage. In this presentation, photopolymers derived from sol-gel matrix and transparent polymer binder are summarized. The effect of monomer composition and plasticizers on optical recording will be discussed based on the monomer transport during the photopolymerization.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1689-1694
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• 2011

There are increasing customer's needs for safe operation and comfort of trains for the passengers as trains are getting fast and developed with advanced components. To meet the needs we developed the system which is able to prevent possible risk elements by transverse vibrations during the train operation. System records the amplitude data of trains vibration and location data from GPS antenna in real time. The system is composed of 5 different functioning modules as following GCPU, GGWD, GIFD, GAID and GPSD. GAID module is detecting amplitude value of vibration which is sensed by bogie hunting sensor's. GFID gets location information where vibration data is detected with GPS Antenna. Once those data is prepared, GCPU testify it's amplitude and decides whether it send those data. When it sends those recorded data, those data are sent to control unit by MVB communication. we expect that this information will help operation and maintenance engineers improve the safety train services. This paper explains train transverse Vibrations data recording system and its major functions which can measure the amplitude of trains's data during the operation and introduces the configuration for the system setup.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.737-740
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• 2009

3D VR modeling data can be used for powerful expression in construction, because it gives help to navigate a construction in 3D space easily. But the current status of VR technique visualizes only an external shape of a construction. A construction has not only its external shape data but also its constructive information. The constructive information is very important and can be expressed as the process of construction and deconstruction. Thus we research on recording and replay interface to manipulate 3D structured objects for the process of construction and deconstruction.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.1-22
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• 2005

There are two important trends in the modern information society, including digital networking and ubiquitous environment. Thus it is strongly required to develop new information storage devices such as high density storages to match the increased data capacity and small size storage devices to be applied to the mobile multimedia electronics. So far, many approaches have been studied for the high density memory, including the holographic memory, super-RENS and near-field recording using solid immersion lens (SIL) or nano-probe for the ODD (Optical Disk Drive) system, and the perpendicular magnetic recording and heat-assisted magnetic recording for the HDD (Hard Disk Drive) system. In addition, new mobile storage devices have been prepared using 0.85" HDD and 30mm ODD systems from a lot of foreign and domestic companies and institutes. In this paper, the recent technology trend for the next generation information storage system is summarized to offer a research motivation and encouragement to new researchers in this field with an emphasis on the technical issues of the increase of data capacity and decrease of device size.

• Sleep Medicine and Psychophysiology
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• v.8 no.1
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• pp.67-71
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• 2001

Independent Component Analysis (ICA) is a blind source separation method using unsupervised learning and mutual information theory created in the late eighties and developed in the nineties. It has already succeeded in separating eye movement artifacts from human scalp EEG recording. Several characteristic sleep waves such as sleep spindle, K-complex, and positive occipital sharp transient of sleep (POSTS) can be recorded during sleep EEG recording. They are used as stage determining factors of sleep staging and might be reflections of unknown neural sources during sleep. We applied the ICA method to sleep EEG for sleep waves separation. Eighteen channel scalp longitudinal bipolar montage was used for the EEG recording. With the sampling rate of 256Hz, digital EEG data were converted into 18 by n matrix which was used as a original data matrix X. Independent source matrix U (18 by n) was obtained by independent component analysis method ($U=W{\timex}X$, where W is an 18 by 18 matrix obtained by ICA procedures). ICA was applied to the original EEG containing sleep spindle, K-complex, and POSTS. Among the 18 independent components, those containing characteristic shape of sleep waves could be identified. Each independent component was reconstructed into original montage by the product of inverse matrix of W (inv(W)) and U. The reconstructed EEG might be a separation of sleep waves without other components of original EEG matrix X. This result (might) demonstrates that characteristic sleep waves may be separated from original EEG of unknown mixed neural origins by the Independent Component Analysis (ICA) method.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.109-113
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• 1993

In this paper, we devised a simple portable digital recorder for a day life ECG signal recording. The system are consisted of ECG amp. part, signal conditioning part. A/D converter, data compression part and digital memory part. An ADPCM algorithm used at data compress part for 50% of data reduction. The maximum lengths of recording times take 3 hours in 1 mega byte memory.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.75-84
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• 2017

It becomes more and more more important for the storage that supports high speed recording and stable access from network environment. As one field of basic science which produces massive astronomical data, VLBI(: Very Long Baseline Interferometer) is now demanding more data writing performance and which is directly related to astronomical observation with high resolution and sensitivity. But most of existing storage are cloud model based for the high throughput of general IT, finance, and administrative service, and therefore it not the best choice for recording of big stream data. Therefore, in this study, we design storage system optimized for high performance of I/O and concurrency. To solve this problem, we implement packet read and writing module through the use of libpcap and pf_ring API on the multi core CPU environment, and build a scalable storage based on software RAID(: Redundant Array of Inexpensive Disks) for the efficient process of incoming data from external network.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.339-344
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• 2001

We propose a method to represent binary data by modulating both the intensity and the phase of uniform plane waves with a twisted-nematic liquid crystal display for holographic digital data storage especially in a disk-shaped recording medium. As far as intensity modulation is concerned, our method is not different from the conventional method, because binary bit values 0 and 1 are represented by the dark (off) and lit (on) states of the liquid crystal display pixels, respectively (or vice versa). With our method, however, the on pixels are also controlled so that the beams passing through them can have one of two different phase delays. If the difference of the two phase delays is close to 180 degrees, we can reduce the dc component of the data image and thus improve the beam intensity uniformity at the holographic recording plane when Fourier plane holograms are recorded. The feasibility of our method is experimentally demonstrated. rated.

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.61-66
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• 2001

Defocused Fourier plane holograms are stored in disk-type holographic memories where thin recording media are used, the areal storage density per hologram and the intensity uniformity of the signal beam at the recording plane are studied. As the pixel pitch of the spatial light modulator that represents binary data increases, the storage density per hologram increases if exact Fourier holograms are stored. When defocused Fourier plane holograms are stored, however, we show that there exists an optimal pixel pitch that maximizes the area storage density per hologram in general, to increase the areal storage density per hologram, f/# of the Fourier transform lens that focuses the data image should be as small as possible. In this case, not only the intensity distribution at the recording plane but also the recording area becomes very sensitive to the degree of defocusing. Therefore, even if the exact Fourier plane holograms are stored, the defocusing effect owing to the medium thickness should be taken into account to achieve the maximal areal storage density per hologram.logram.