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A Light Weight, Energy Effcient Household Polysomnography (PSG) System Developed
A smart ‘household polysomnography (PSG) system’ was developed by domestic research team.
Professor Yoo Hui Joon and his research team of KAIST’s department of Electricity and Electronic Engineering successfully developed a PSG system that is light weight and has high performance levels. The conventional PSG systems were complex with numerous lines and wires.
The PSG is used to monitor biological signals during sleep and the monitored results are used to diagnose and cure sleep-related illnesses and disorders. However because of restrictions like the size of the machine, impurities, and the change in environment, multiple trials over several days were required to obtain accurate data.
The system developed by the research team is lighter than a q-tip so as to not disturb the patient’s sleep. It also has Intelligent Circuit (IC) that detects when sensors come detached and automatically replaces the sensor with another sensor thereby allowing continual monitoring of the user.
A low-power consuming circuit was implemented allowing the entire system to run continuously on a single coin battery for 10 hours which effectively decreased the weight of the system and simultaneously allows for uninterrupted monitoring of the user over the entire sleep cycle.
Even a remote diagnosis system can be implemented. The user will don the PSG and sleep at home, ensuring that a normal heat beat rate, brain waves, breathing, etc. will be monitored. The data procured overnight can be sent to the experts online who will be able to diagnose remotely.
The research team plans on performing research in cooperation with the KAIST hospital and U-Healthcare research.
The research result is winning worldwide rave. The system was announced in the International Solid-State Circuits Conference (ISSCC) and was published in ISSCC magazine and in Japan’s NIKKEI Electronics January edition.
2011.03.25 View 10789 -
Soyeon's Odyssey by Space Travel, Feb. 1, 2011
Soyeon Yi, an alumna of KAIST who joined the Soyuz TMA-12 mission to the International Space Station in 2008 and successfully returned to the Earth after completion of her mission. She is often cited as the first Korean astronaut who had spaceflight. She recently had an interview with an Australian based online newspaper that publishes space related news stories. For the interview, please go to the link.
http://www.space-travel.com/reports/Soyeon_Odyssey_999.html
2011.02.02 View 8901
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Nanowerk Spotlight: Bacteria as environmentally friendly nanoparticle factories, Sep. 24, 2010
The Nanowerk.com is a leading portal site for nanotechnology and nanosciences, which runs a daily news section called “Spotlight.” On September 24, 2010, the Spotlight published an article on the latest developments of the research by a KAIST team headed by Distinguished Professor Sang-Yup Lee of the Chemical and Bimolecular Engineering Department. For the article, please click the link below:
Nanowerk Spotlight: Bacteria as environmentally friendly nanoparticle factories, Sep. 24, 2010
By Michael Berger.
http://www.nanowerk.com/spotlight/spotid=18188.php
2010.09.25 View 9991
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Nature Photonics, a peer-reviewed scientific journal, released a paper written by a KAIST research team on the time-of-flight measurement.
Professor Seung-Woo Kim of the Mechanical Engineering Department, KAIST, and his research team published the result of their study on the measurement of 1 nanometer (nm) precision.
“The time-of-flight of light pulses has long been used as a direct measure of distance, but state-of-the-art measurement precision using conventional light pulses or microwaves peaks at only several hundreds of micrometers. Here, we improve the time-of-flight precision to the nanometer regime by timing femtosecond pulses through phase-locking control of the pulse repetition rate using the optical cross-correlation technique,” Professor Kim said.
According to the experiment conducted by the research team, “An Allan deviation of 117 nm in measuring a 700m distance in air at a sampling rate of 5 millisecond (ms) once the pulse repetition is phased-locked, which reduces to 7 nm as the averaging time increases to 1 second (s).”
When measuring an object located in a far distance, a laser beam is projected to the object, and the reflected light is analyzed; the light is then converted into an electric signal to calculate the distance. In so doing, Professor Kim said, the conventional method of measurement creates at least 1 mm of deviation.
He argues, “This enhanced capability is maintained at long range without periodic ambiguity, and is well suited to lidar applications. This method could also be applied to future space missions involving formation-flying satellites for synthetic aperture imaging and remote experiments related to general relativity theory."
Nature Photonics published the article online on August 8, 2010.
2010.08.18 View 10833 -
Photonic crystals allow the fabrication of miniaturized spectrometers
By Courtesy of Nanowerk
Photonic crystals allow the fabrication of miniaturized spectrometers
(Nanowerk Spotlight) Spectrometers are used in materials analysis by measuring the absorption of light by a surface or chemical substance. These instruments measure properties of light over a specific portion of the electromagnetic spectrum. In conventional spectrometers, a diffraction grating splits the light source into several beams with different propagation directions according to the wavelength of the light. Thus, to achieve sufficient spatial separation for intensity measurements at a small slit, a long light path – i.e., a large instrument – is required.
However, for lab-on-a-chip or microTAS (total analysis system) applications, the spectrometer must be integrated into a sub-centimeter scale device to produce a stand-alone platform. To achieve this, researchers at the Korea Advanced Institute of Science and Technology (KAIST) propose a new paradigm in which the spectrometer is based on an array of photonic crystals with different bandgaps.
"Because photonic crystals refelct light of different wavelengths selectively depending on their bandgaps, we can generate reflected light spanning the entire wavelength range for analysis at different spatial positions using patterned photonic crystals," Seung-Man Yang, Director of the National Creative Research Initiative Center for Intergrated Optofluidic Systems and Professor of the Department of Chemical & Biomolecular Engineering at KAIST, tells Nanowerk. "Therefore, when the light source impinges on the patterned photonic crytals, we can construct the spectrum using the reflection intensity profile from the constituent photonic crystals."
Photonic crystals – also known as photonic band gap material – are similar to semiconductors, only that the electrons are replaced by photons (i.e. light). By creating periodic structures out of materials with contrast in their dielectric constants, it becomes possible to guide the flow of light through the photonic crystals in a way similar to how electrons are directed through doped regions of semiconductors. The photonic band gap (that forbids propagation of a certain frequency range of light) gives rise to distinct optical phenomena and enables one to control light with amazing facility and produce effects that are impossible with conventional optics.
To demonstrate this new concept based on patterned photonic crystals, Yang and his group used non-close-packed colloidal crystals of silica particles dispersed in photocurable resin. Due to the repulsive interparticle potential, monodisperse silica particles spontaneously crystallize into non-close-packed face-centered cubic (fcc) structures at volume fractions above 0.1. Therefore, the particle volume fraction determines both the lattice constant and the bandgap position.
a) Optical image of an ETPTA film containing porous photonic crystal stripe patterns with 20 different bandgaps. b) Reflectance spectra from the 20 strips. c) Optical microscope image of the middle region with the parallel stripe pattern (denoted as white-dotted box in a). d) Cross-sectional SEM images of first, sixth, eleventh and seventeenth strips. The scale bars in a, c and d are 1 cm, 2mm and 2 µm, respectively. (reprinted with permission from Wiley-VCH Verlag)
Reporting their findings in a recent issue of Advanced Materials ("Integration of Colloidal Photonic Crystals toward Miniaturized Spectrometers"), the KAIST team has demonstrated the integration of colloidal photonic crystals with 20 different bandgaps into freestanding films (prepared by soft lithography), and their application as a spectrometer.
Yang explains that the team was able to precisely control the photonic bandgap by varying the particle size and volume fration.
"The prepared colloidal composite structures showed high physical rigidity and chemical resistivity" he says. "The composite structure is suitable for spectroscopic use due to the small full widths at half maximum (FWHMs) of the reflectance spectra, which mean that there is little overlap of the reflectance spectra of neighboring photonic crystal strips."
"On the other hand" says Yang, "porous photonic crystals showed large FWHMs and high reflectivities, which should prove useful in many practical photonic applications that require high optical performance and physical rigidity as well as simple and inexpensive preparation."
In addition to fabricating miniaturized spectrometers, which can for instance be integrated into small lab-on-a-chip devices, these integrated photonic crystals can be potentially used for tunable band reflection mirrors, optical switches, and tunable lasing cavities. Moreover, patterned photonic crystals with RGB colors are well-suited for use in reflection-mode microdisplay devices.
Yang points out that, although the spectrometric resolution can be reduced by employing the smaller bandgap interval and photonic bandwidth, there is a limitation. "Now, we are studying photonic crystals with continuous modulation of bandgap position. We expect that the photonic crystals can reduce the resolution to 0.01 nm."
By Michael Berger. Copyright 2010 Nanowerk
2010.03.17 View 13062
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Prof. Choi Unveils Method to Improve Emission Efficiency of OLED
A KAIST research team led by Prof. Kyung-Cheol Choi of the School of Electrical Engineering & Computer Science discovered the surface plasmon-enhanced spontaneous emission based on an organic light-emitting device (OLED), a finding expected to improve OLED"s emission efficiency, KAIST authorities said on Thursday (July 9).
For surface plasmon localization, silver nanoparticles were thermally deposited in a high vacuum on cathode. Since plasmons provide a strong oscillator decay channel, time-resolved photoluninescene (PL) results displayed a 1.75-fold increased emission rate, and continuous wave PL results showed a twofold enhanced intensity.
"The method using surface plasmon represents a new technology to enhance the emission efficiency of OLED. It is expected to greatly contribute to the development of new technologies in OLED and flexible display, as well as securing original technology," Prof. Choi said.
The finding was published in the April issue of Applied Physics Letters and the June 25 issue of Optics Express. It will be also featured as the research highlight of the August issue of Nature Photonics and Virtual Journal of Ultrafast Science.
2009.07.09 View 19110 -
New System to Generate Extreme-Ultraviolet Light Developed
A KAIST research team led by Prof. Seung-Woo Kim of the Mechanical Engineering Department developed a new system for generating coherent extreme-ultraviolet (EUV) light, school authorities announced on June 5.
The new system comes in a metallic nano-structure consisting of a two-dimensional array of gold "bow tie" elements on a sapphire plate. The new process was featured in the British journal Nature on June 5.
The properties of coherent EUV light make it a prime candidate for exciting technological applications. But, at present, the equipment needed to generate the short-wavelength light is costly and bulky. The system developed by Prof. Kim"s research team is expected to reduce both cost and bulk.
The new system uses the conventional principle of high-harmonic generation via the interaction of a femtosecond laser pulse with a gas, but adopts the novel concept of amplifying light by way of local plasmon field enhancement, according to the research team.
2008.06.10 View 12439 -
Gold prize for Sungkoo Yeo and silver prize for Youngsik Kim at 'Samsung Electrics paper contest'
Gold prize for Sungkoo Yeo and silver prize for Youngsik Kim at ‘Samsung Electrics paper contest’
Sungkoo Yeo, doctorate student at the division of Electrical Engineering, and Youngsik Kim, doctorate students at the division of Mechanical Engineering, won gold and silver prizes respectively at ‘the 2nd Inside edge paper contest’ organized by Samsung Electronics.
Yeo, under the supervisory of Professor Youngse Kwon, won the glory of gold prize in recognition of his highly evaluated researches in the fields of silicon-based micro mold manufacturing technologies and fine shaping technologies revealed by his paper of ‘"Fabrication of Microlens array Using PDMS Replica Molding and Oxidized Porous Silicon Bulk Micromachining’.
Kim, under the supervisory of Professor Seungwoo Kim, also won the silver prize for his research performances over the thickness pattern measuring technologies of transparent thin film coated on the pattern of an opaque metal in the field of optical technology unveiled by his paper of "Dispersive white-light interferometry for in-line inspection of thin-film layers on patterned structures".
Inside Edge paper contest is an academic paper contest organized by Samsung Electronics to reveal the fresh ideas and potential technologies of the young talented.
2006.11.27 View 15241
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Sungil Chung listed in Who's Who following last year
Sungil Chung listed in Who’s Who following last year
Sungil Chung, senior researcher of KAIST Satellite Technology Research Center (STRC), is listed in the international biographical dictionary Marquis Who"s Who’s Who’s Who in the America Edition 2007 following last year. He is also listed in the first edition of Who’s Who of Emerging Leaders.
Ph.D. Chung majored in Electrohydrodynamics (EHD) at Texas A&M University and worked at NASA’s Goddard Space Flight Center for a research in the field of aerospace vehicle-related thermal control. He has worked at KAIST STRC as senior researcher from September this year.
He has won an Innovation and Creativity Prize Paper Award from the U.S. Institute of Electrical and Electronics Engineers (IEEE) in 2004.
2006.11.16 View 15053