• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.389.2-389.2
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• 2016

The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.7-10
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• 2005

Plant water deficiency during drought season causes physiological stress and can be a critical indicator of forest fire vulnerability. In this study, we attempt to analyze the spectral characteristics of water stressed vegetation by using the laboratory measurement on leaf samples and the canopy reflectance spectra extracted from satellite hyperspectral image data. Leaf-level reflectance spectra were measured by varying moisture content using a portable spectro-radiometer. Canopy reflectance spectra of sample forest stands of two primary species (pine and oak) located in central part of the Korean peninsula were extracted from EO-l Hyperion imaging spectrometer data obtained during the drought season in 2001 and the normal precipitation year in 2002. The preliminary analysis on the reflectance spectra shows that the spectral characteristics of leaf samples are not compatible with the ones obtained from canopy level. Although moisture content of vegetation can be influential to the radiant flux reflected from leaf-level, it may not be very straightforward to obtain the spectral characteristics that are directly related to the level of canopy moisture content. Canopy spectra form forest stands can be varied by structural variables (such as LAt, percent coverage, and biomass) other than canopy moisture content.

• Imaging Science in Dentistry
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• v.42 no.1
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• pp.1-4
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• 2012

Purpose : Hand-held dental x-ray system is a self contained x-ray machine designed to perform intraoral radiography with one or two hands. The issue about its usage as general dental radiography is still in dispute. The aim of the present study was to assess the relationship between the amount of battery charge and the tube voltage in different handheld dental x-ray systems. Materials and Methods : Seven hand-held dental x-ray units were used for the study. Tube voltage was measured with Unfors ThinX RAD (Unfors Instruments AB, Billdal, Sweden) for 3 consecutive exposures at the different amount of battery charge of each unit. The average and the deviation percentage of measured kV from indicated kV of each unit were calculated. Results : Tube voltage of only 1 unit was 70 kV (indicated by manufacturer) and those of the others were 60 kV. Tube voltage deviation percentage from the indicated kV at the fully charged battery was from 2.5% to -5.5% and from -0.8% to -10.0% at the lowest charged battery. Conclusion : Tube voltages of all units decreased as the residual amount of the battery charge decreased. It is suggested that the performance test for hand-held x-ray system should be performed for the minimum residual charged battery as well as the full charged one. Persistent battery charging is suggested to maintain the proper tube voltage of the hand-held portable x-ray system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.161-166
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• 2021

When testing various images outdoors with an infrared imaging system, it is necessary to save the tested images for comparison. In addition, after the test, it should be possible to easily connect to the PC and download the stored data. With the recent development of the memory system, it is possible to design an infrared image storage board for an outdoor test by using the eMMC memory that can be easily used in the form of an on board. In this paper, we describe the design of a portable image storage board that can easily store and download infrared images, and describe the GUI program that can connect to a PC and download the stored images.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.291-299
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• 1997

As a microimaging device detecting gamma rays emitted from small lesions or tumors during operation, the intraoperative surgical probe has been proposed and is now under development. We have designed a multipurpose portable gamma prove system and evaluated the performance both for the absolute counting purpose of residual radioactivities and for the localizing capability of gamma events using the NaI(Tl) crystal and two types of photomultiplier tubes(PMTs). Counting efficiencies in the range of routine clinical use of radiation dose were measured using the assembly of single channel PMTs and 0.5 inch thick NaI(Tl) crystal of 1 inch diameter. The positioning of gamma events for imaging purpose requires the multiple channel PMTs with appropriate positioning electronics. We have designed a simple and reliable positioning circuit based on the concept of modified Anger. In preliminary experiments using the multiple channel PMT of 3 inch diameter and the dim lighth source, we were able to trace and localize the correct position with reduced positioning error by the use of two multiplier/divider chipset and simplified peripherals. The energy resolutions for the counting gamma probe measured as full width at half maximum(FWHM) for Cs-137, F-18, Tc-99m were 12%, 13%, and 36%, respectively. The spatial resolution for the imaging gamma probe measured as FWHM for green LED was 2.9 mm. The results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine. Future studies will include developing collimators, improving interface hardwares, and evaluating the system with clinical data.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.1-10
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• 2012

This paper proposes design space exploration methodology of many-core processors including multimedia specific instructions to support high-performance and low power ultrasound imaging for portable devices. To explore the impact of multimedia instructions, we compare programs using multimedia instructions and baseline programs with a same many-core processor in terms of execution time, energy efficiency, and area efficiency. Experimental results using a $256{\times}256$ ultrasound image indicate that programs using multimedia instructions achieve 3.16 times of execution time, 8.13 times of energy efficiency, and 3.16 times of area efficiency over the baseline programs, respectively. Likewise, programs using multimedia instructions outperform the baseline programs using a $240{\times}320$ image (2.16 times of execution time, 4.04 times of energy efficiency, 2.16 times of area efficiency) as well as using a $240{\times}400$ image (2.25 times of execution time, 4.34 times of energy efficiency, 2.25 times of area efficiency). In addition, we explore optimal PE architecture of many-core processors including multimedia instructions by varying the number of PEs and memory size.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.163-173
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• 2011

In this paper, we propose a new paradigm of augmented reality board game environment and a portable game assistant(PGA) which can help gamers with strategy information. Previous AR board games consist of a private and public space. The public space provides rules of the game and shows the scene of game. And the gamers control game pieces in the public space. The previous games use the RFIDs for recognizing positions of the pieces, and the VR/AR environment for providing the scene of the game. However the RFIDs are expansive, and the VR/AR environment is inconvenient because it uses additional devices: the DataGlove, the digital pen, and the HMD. The proposed system recognizes positions of real pieces using the computer vision technique, and uses a monitor to provide dynamic effects. In the private space, previous systems provide entire screen of game and position of specific pieces, but cannot be controled the pieces by gamers. Therefore, in this system, we provide PGA that helps the user to plan of the strategy individually using universally mobile. The PGA helps to plan the strategy in the individual area, and to play easily in the side of the user's convenience.

• Applied Microscopy
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• v.34 no.1
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• pp.13-21
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• 2004

The high voltage electron microscope (HVEM) newly installed in KBSI is an advanced transmission electron microscope capable of atomic resolution (${\leq}1.2{\AA}$ point-to-point resolution) together with high titling function (${\pm}60^{\circ}$), which are suitable to do 3-dimensional atomic imaging of a specimen. In addition, the instrument can be controlled by remote operation system, named as 'FasTEM' for the HVEM, which is favorable to overcome some environmental obstacles resulting from the direct operation. The FasTEM remote operation system has been established between the headquarter of KBSI in Daejeon and the Seoul branch. The server system in the headquarter has been connected with a portable client console system in the Seoul branch using an advanced internet resource, 'KOREN' of 155 Mbps grade. Most of the HVEM functions essential to do remote operation are available on the portable client console. The experiment to acquire the high resolution image of [001] Au has been achieved by excellent transmission of control signals and communication with the HVEM. Real-time reaction like direct operation, such as controls of the illumination and projection parameters, acquisition and adjustment of each detector signal, and electrical steering of each motor-driven system has been realized in remote site. It is positively anticipated that the first remote operation of HVEM in conjunction with IT infraengineering plays a important role in constructing the network based e-Science Grid in Korea for national user s facilities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.spc
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• pp.11-17
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• 2022

In this study, we address the development of a floating platform system based on a unmanned surface vessel for wide-area sensing and monitoring of hazardous and noxious substances (HNSs). For long endurance, a movable floating platform with no mooring lines was used and modified for HNS sensing and monitoring. The floating platform was equipped with various sensors such as optical and thermal imaging cameras, marine radar, and sensors for detecting HNSs in water and air. Additionally, for experiment validation in real outdoor environments, a portable gas-exposure system (PGS) was built and installed on the monitoring system. The software for carrying out the mission was integrated with the Robot Operating System (ROS) framework. The practical feasibility of the developed system was verified through experimental tests conducted in inland water and real-sea environments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1189-1193
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• 2012

The Miniaturized Fingerprint Imager (MFI) is a slim optical mouse that can be used as an input device for application to wireless portable personnel communication devices such as smartphones. In this study, we have fabricated key optical components of an MFI, including the illumination optical components and imaging lens. An LED beam-shaping lens consisting of an aspheric lens and a Fresnel facet was successfully machined using a diamond turning machine (DTM). A customized V-shaped groove for beam path banding was fabricated by the bulk micromachining of silicon that was coated with aluminum using the shadow effect in thermal evaporation. The imaging lens and arrayed multilevel Fresnel lenses were fabricated by electron beam lithography and FAB etching, respectively. The proposed optical components are extremely compact and have high optical efficiency; therefore, they are applicable to ultraslim optical systems.