• Korean Journal of Optics and Photonics
• /
• v.8 no.3
• /
• pp.245-249
• /
• 1997

An electro-optic polymer digital optical switch with a coupling region modified for optimum coupling is designed and demonstrated. Its branch waveguide is fabricated by reactive ion etching. Then, the modified coupling region is adiabatically introduced along the propagation direction from the branching point of the two waveguides, and it is implemented by photobleaching after the device fabrication. The structure of the modified coupling region and its refractive index profiles are designed to optimize and mode coupling in the Y-branch waveguide. Therefore, the switching performance of the device was shown to be enhanced with a fixed device length. The measured drive voltage is reduced by more than 30 percents, and the crosstalk is also improved by about 4~6 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.4 s.119
• /
• pp.379-388
• /
• 2007

This paper presents a real-time respiration and heartbeat detector comprised of a 1.6 GHz single-channel Doppler sensor and analog/digital signal processing block for remote vital sign detection. The RF front end of the Doppler sensor consists of an oscillator, mixer, low noise amplifier, branch-line hybrid and patch antenna. We apply artificial transmission lines(ATLs) to the branch-line hybrid, which leads to a size reduction of 40 % in the hybrid, while its performance is very comparable to that of a conventional hybrid. The analog signal conditioning block is implemented using second order Sallen-Key active filters and the digital signal processing block is realized with a LabVIEW program on a computer. The respiration and heartbeat detection is demonstrated at a distance of 50 cm using the developed system.

• Ocean and Polar Research
• /
• v.31 no.1
• /
• pp.111-119
• /
• 2009

Biogenic surface films, which are often present in coastal areas, may enhance the signatures of hydrodynamic processes in microwave, optical, and infrared imagery. We analyzed ERS-1/2 Synthetic Aperture Radar (SAR) and Envisat Advanced Synthetic Aperture Radar (ASAR) images taken over the Japan/East Sea (JES). We focused on the appearance of the contrast SAR signatures, particularly the dark features of different scales caused by various oceanic and atmospheric phenomena. Spiral eddies of different scales were detected through surface film patterns both near the coast and in the open regions of the JES in warm and cold seasons. During field experiments carried out at the Pacific Oceanological Institute (POI) Marine Station 'Cape Shults' in Peter the Great Bay, the sea surface roughness characteristics were measured during the day and night using a developed polarization spectrophotometer and various digital cameras and systems of floats. The velocity of natural and artificial slicks was estimated using video and ADCP time series of tracers deployed on the sea surface. The slopes of gravity-capillary wave power spectra varied between .4 and .5. Surface currents in the natural and artificial slicks increased with the distance from the coast, varying between 4 and 40 cm/s. The contrast of biogenic and anthropogenic slicks detected on vertical and horizontal polarization images against the background varied over a wide range. SAR images and ancillary satellite and field data were processed and analyzed using specialized GIS for marine coastal areas.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.102-106
• /
• 2003

In this paper, we propose a novel model and authoring method of digital contents which improves the educational effects in the area of cyber educations through Web. Especially we offer a new model of contents authoring for engineering departs using JAVA technology and concept-based branch strategy, making unit-contents separated in accordance with their characteristics and then accessing them at arbitrary instant in the replaying time. In proportion to the proposed model and strategy, the resultant contents might show advanced adaptabilities and interactions for users and the educational effects are really improved. Combining and realizing the proposed conceptual branch method and JAVA applet library with the conventional page-branch or subject-blanch we expect to get a novel basic scenario of engineering cyber contents and the scenario might improve the authoring and educational effects of the contents by applying its good interactive properties and realistic operations.

• Journal of Digital Convergence
• /
• v.18 no.5
• /
• pp.425-432
• /
• 2020

Stereoscopic imaging is an important branch in the field of digital imaging, and has grown significantly over the last two decades through research and development. Hologram projection technology based on stereoscopic technology has been a social issue since the development of the Hungarian physicist Daniel Garber in 1947. It is becoming more and more important as stereoscopic works using similar technologies are applied to various fields. This study analyzed content cases using classical and creative stereoscopic technology from the perspective of digital image content design and explored the multiprotocol direction of holographic projection.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.5
• /
• pp.851-860
• /
• 2014

With an increasing demand of powerful electronic goods, smart TV containing network module with digital TV gets more popular. These change are meaningful from a digital forensics perspective because smart TV store more user's data than digital TV. In this paper, we suggest smart TV forensics as a branch of digital forensics. With smart TV forensics, investigator can trace more wide age group's activities than existing digital forensics analysis.

• Annals of Clinical Neurophysiology
• /
• v.14 no.1
• /
• pp.41-44
• /
• 2012

Thenar motor neuropathy (TMN) is a compressive mononeuropathy of recurrent motor branch of median nerve. It is infrequent and may have different pathogenesis. It may be a unique entity of disease or considered a variant of carpal tunnel syndrome involving the motor branch only. We report a case of TMN induced by vigorous massage that applied strong digital pressure in the region of the base of palm and thenar muscles.

• Steel and Composite Structures
• /
• v.29 no.3
• /
• pp.349-362
• /
• 2018

Thermal buckling behavior of porous functionally graded nanobeam integrated with piezoelectric sensor and actuator based on the nonlocal higher-order shear deformation beam theory is investigated for the first time. Its material properties are assumed to be temperature-dependent and varying along the thickness direction according to the modified power-law rule. Note that the porosity with even type is considered herein. The equations of motion are obtained through Hamilton's principle. The influences of several parameters (such as type of temperature distribution, external electric voltage, material composition, porosity, small-scale effect, Ker foundation parameters, and beam thickness) on the thermal buckling of FG nanobeam are investigated in detail.

• Journal of Multimedia Information System
• /
• v.3 no.3
• /
• pp.47-52
• /
• 2016

This research paper examines the usage of graphic imaging in Holographic Projections to further advance the medical field. It highlights the importance and necessity of this technology as well as avant-garde techniques applied in the process of displaying images in digital holography. This paper also discusses the different types of applications for holograms in society today. Different tools were utilized to transfer a set of a cancer patient's brain tumor data into data used to produce a 3D holographic image. This image was produced through the transfer of data from one program to another. Through the use of semi-automatic segmentation through the seed region method, we were able to create a 3D visualization from Computed Tomography (CT) data.

• Journal of Power Electronics
• /
• v.15 no.6
• /
• pp.1577-1583
• /
• 2015

In this research, a combined adaptive-robust current controller is developed for non-minimum-phase DC-DC converters in a wide range of operations. In the proposed nonlinear controller, load resistance, input voltage and zero interval of the inductor current are estimated using developed adaptation rules and knowing the operating mode of the converter for the closed-loop control is not required; hence, a single controller can be employed for a wide load and line changes in discontinuous and continuous conduction operations. Using the TMS320F2810 digital signal processor, the experimental response of the proposed controller is presented in different operating points of the buck/boost converter. During transition between different modes of the converter, the developed controller has a better dynamic response compared with previously reported adaptive nonlinear approach. Moreover, output voltage steady-state error is zero in different conditions.