research
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Indoor Localization System for Mobile Devices Developed by KAIST Research Team
The technology will be available to smart phone users around the world through Goole Apps Store.
The wireless fidelity (WiFi)-based indoor localization can be installed on smart phones for commercialization, a technology developed by a research team at KAIST. The KAIST research team, led by Professor Dong-Soo Han, Department of Computer Science and Engineering, explained that the technology offers smart phone users, e.g., Google’s Android phone and Apple’ iPhone, a unique way to recognize their location through WiFi Open Radio Map. WiFi Open Radio Map is built with WiFi Location Fingerprint that contains wireless local area network (LAN)’s signal strength and wireless access points (AP) number, and with location information.
Through using the Map, WiFi-based indoor localization recognizes the location of smart phones and sends the location information to the phones. Since the technology uses WiFi signal information only to recognize the whereabouts of phones, it can be widely used in the future, without installing extra machines and equipment for detection, for a complicated, large indoor environment, where the Global Positioning System (GPS) is not available.
Currently, Professor Han has established WiFi Open Radio Map inside and outside of a few buildings at KAIST and developed several location based application services to perform a beta testing. He plans to open and distribute the technology to smart phone users through Google and Apple Apps Store in early 2010. Collaborations with major smart phone makers such as SK Telecom, Korea Telecom, and Samsung as well as outdoor/indoor localization manufactures and suppliers will also be sought, according to Professor Han.
Professor Han is invited to an international conference, Eighth Annual IEEE International Conference on Pervasive Computing and Communications, slated for early April 2010, in recognition of his work. At the conference, he will give a presentation on WiFi based indoor localization technology and conduct its demo version.
2010.02.10 View 12499 -
KAIST Research Team Identified Promising New Source to Obtain Stem Cells
KAIST Research Team Identified Promising New Source to Obtain Stem Cells
A research team at KAIST led by Professor Gou-Young Koh, M.D. and Ph.D., of the Department of Biological Sciences, has found evidence that fat tissue, known as adipose tissue, may be a promising new source of valuable and easy-to-obtain regenerative cells called hematopoietic stem and progenitor cells (HSPCs).
HSPCs are adult stem cells that have the ability to generate and develop into many different kinds of cells. They are now used to repair damaged tissues and are being studied for their potential to treat a vast array of chronic and degenerative conditions such as leukemia. Mostly found in bone marrow but with a limited quantity, HSPCs are hard to cultivate in vitro, thus becoming an obstacle to use them for research and therapeutic purposes.
Within the adipose tissue is a special cell population known as the stromal vascular fraction (SVF), which share similar properties to those in the bone marrow. Cells in the bone marrow and SVF have the ability to differentiate into several cell types. In addition, both adipose and bone marrow offer similar environments for optimal stem cell growth and reproduction.
Given the fact that adipose and bone marrow tissues share similar properties, Dr. Koh and his team conducted a research, injecting granulocyte colony-stimulating factor (G-CSF), a growth hormone used to encourage the development of stem cells, into an adipose tissue of a mouse whose bone marrow is damaged. As a result, the team has found that the SVF derived from adipose tissue contains functional HSPCs capable of generating hematopoietic (blood-forming) cells to repair the damaged bone morrow.
The Ministry of Education, Science and Technology nominated the KAIST research as one of its sponsoring 21st Century Frontier R&D Programs. Director Dong-Wook Kim of Stem Cell Research Center (SCRS) that oversees the KAIST team expressed a possibility to use the adipose tissue as an alternative source to obtain stem cells for regeneration medicine.
Dr. Koh also said, “It’s been a well known method to extract HSPCs from the bone morrow or blood, but it’s the first time to identify adipose tissue, before considered useless, as a new possible supplier for functional and transplantable HSPCs.”
The study results have received an important recognition from the academia—the American Society of Hematology published the research as a main article in its official journal, Blood, for the February 4th, 2010 issue, which is the most citied peer-reviewed publication in the field.
2010.02.05 View 13048
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Prof. Lee"s Team Succeeds in Producing Plastics Without Use of Fossil Fuels
A team of scientists led by Prof. Sang-Yup Lee of the Department of Biological Sciences at KAIST have succeeded in producing the polymers used for everyday plastics through bioengineering, rather than through the use of fossil fuel based chemicals, the university authorities said on Tuesday (Nov. 24).
This groundbreaking research, which may now allow for the production of environmentally conscious plastics, has been published in two papers in the journal Biotechnology and Bioengineering.
Polymers are molecules found in everyday life in the form of plastics and rubbers. The team consisted of scientists from KAIST and Korean chemical company LG Chem focused their research on polylactic acid (PLA), a bio-based polymer which holds the key to producing plastics through natural and renewable resources.
"The polyesters and other polymers we use everyday are mostly derived from fossil oils made through the refinery or chemical process," said Lee. "The idea of producing polymers from renewable biomass has attracted much attention due to the increasing concerns of environmental problems and the limited nature of fossil resources. PLA is considered a good alternative to petroleum based plastics as it is both biodegradable and has a low toxicity to humans."
Until now PLA has been produced in a two-step fermentation and chemical process of polymerization, which is both complex and expensive. Now, through the use of a metabolically engineered strain of E.coli, the team has developed a one-stage process which produces polylactic acid and its copolymers through direct fermentation. This makes the renewable production of PLA and lactate-containing copolymers cheaper and more commercially viable.
"By developing a strategy which combines metabolic engineering and enzyme engineering, we"ve developed an efficient bio-based one-step production process for PLA and its copolymers," said Lee. "This means that a developed E. coli strain is now capable of efficiently producing unnatural polymers, through a one-step fermentation process,"
This combined approach of systems-level metabolic engineering and enzyme engineering now allows for the production of polymer and polyester based products through direct microbial fermentation of renewable resources.
"Global warming and other environmental problems are urging us to develop sustainable processes based on renewable resources," concluded Lee. "This new strategy should be generally useful for developing other engineered organisms capable of producing various unnatural polymers by direct fermentation from renewable resources".
2009.11.30 View 15478 -
Prof. Woo's Team Discovers Eco-Friendly Solid-Oxide Fuel Cell System
A KAIST research team led by Prof. Seong-Ihl Woo of the Department of Chemical & Biomolecular Engineering has found a method to use glycerol, a byproduct from the production of biodiesel, as fuel for solid oxide fuel cells (SOFC), university authorities said on Tuesday (Oct. 27).
The research finding shows that glycerol can be an environmentally sustainable fuel when it is used for operating SOFCs with internal reforming, instead of hydrogen and methane. The finding was published in the Oct. 14, 2009 online edition of ChemSusChem, a sister journal of Angewandte Chemie, the world"s leading chemistry journal.
Biodiesel is an attractive alternative energy source because of its low sulfur content and demand is growing worldwide as oil price soars. Bio-derived glycerol will not contribute to the greenhouse effect and has the potential to contribute to reducing global warming.
Currently, glycereol is used as a raw material in the cosmetic, pharmacy, food, and tobacco industries. However, its supply exceeds its demand as the volume of biodiesel production increases. The production of 1 ton of biodiesel produces 0.1 ton of glycerol. Many researchers have investigated various routes for the consumption of surplus glycerol.
The research is expected to contribute to sustainable growth by reducing the emissions of carbon dioxide and reusing generated carbon dioxide for the production of biomass. The new method enables manufacturers to use glycerol as a fuel for operating SOFC.
2009.10.28 View 13979 -
Prof. Ryoo's Team Discovers Breakthrough Method to Create New Zeolite
A group of scientists led by Prof. Ryong Ryoo of the Department of Chemistry, KAIST, has found a method to direct the growth of zeolite, a crystalline substance that is frequently used as catalyst in the chemical and petrochemical industries, the university authorities said on Thursday (Sept. 10).
Ryoo"s research team successfully created ultrathin nano-sheets, only two nano-meters thick, that are efficiently used as long-life catalysts for hydrocarbon cracking and other petrochemical applications. The breakthrough finding, which is credited with taking acidic zeolite catalysts to the limit in terms of thickness, was published in the latest edition of the peer-review journal, "Nature."
A team from the Polytechnic Univeristy of Valencia, Spain, also contributed to the research.
Zeolites are already widely used in the petrochemical industry, but making the catalysts very thin means that reactant molecules can easily diffuse into the zeolite structure and product molecules can get out quickly. This improves the efficiency of the catalyst and reduces unwanted side reactions that can produce polymeric hydrocarbon "coke" that clogs the zeolite pores and eventually kills the catalytic activity, Prof. Yoo said.
To make the thin sheets, Ryoo and his team used a surfactant as a template to direct the growth of the zeolite structure. The surfactant molecule has a polar "head" group - with two quaternary ammonium groups around which the aluminosilicate zeolite crystal grows - and a long hydrocarbon "tail," which prevents the sheets from aggregating together into larger, three dimensional crystals. When the surfactant is removed, these flakes pile up randomly with gaps in between which further aids diffusion to the catalyst sites.
"Zeolite could be used as a catalyst to convert heavy oil into gasoline. Our new zeolite could provide even more possibilities, such as being used as catalysts for transforming methanol into gasline," Ryoo said.
Prof. Ryoo, a Distinguished Professor of KAIST, has won a variety of academic awards, which included the Top Scientist Award given by the Korean government in 2005 and the 2001 KOSEF Science and Technology Award for his work on the synthesis and crystal structure of mezzoporous silica.
Ryoo obtained his bachelor"s degree from Seoul National University in 1977, master"s from KAIST in 1979, and doctorate from Stanford University in 1985.
In 2006, Ryoo and his research team announced the discovery of a form of zeolite that can catalyze petrochemical reactions much more effectively than previous zeolites. Because of the potential of this to streamline the gasoline refining process, it was greeted as a "magical substance" by the South Korean press.
2009.09.11 View 12957 -
Scaling Laws between Population and Facility Densities Found
A research team led by Prof. Ha-Woong Jeong of the Department of Physics, KAIST, has found a positive correlation between facilities and population densities, university authorities said on Tuesday (Sept. 2). The research was conducted in the cooperation with a research team of Prof. Beom-Jun Kim at Sungkyunkwan University.
The researchers investigated the ideal relation between the population and the facilities within the framework of an economic mechanism governing microdynamics.
In previous studies based on the global optimization of facility positions in minimizing the overall travel distance between people and facilities, the relation between population and facilities should follow a simple law. The new empirical analysis, however, determined that the law is not a fixed value but spreads in a broad range depending on facility types.
To explain this discrepancy, the researchers proposed a model based on economic mechanism that mimics the competitive balance between the profit of the facilities and the social opportunity cost for population.
The results were published in the Proceedings of the National Academy of Sciences of the United States on Aug. 25.
2009.09.04 View 13806
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Prof. Lee"s Team Pioneers Biotechnological Production of Chemical Using Renewable Materials
A research team led by Prof. Sang-Yup Lee of the Bio and Brain Engineering Department at KAIST has succeeded in engineering the bacterium E. coli to produce the industrial chemical putrescine, university authorities said on Monday (Aug. 31).
Putrescine, a four carbon chain diamine, is an important platform chemical with a wide range of applications for the pharmaceutical, agrochemical and chemical industries. It is currently used to synthesize nylon-4,6, a widely used engineering plastic.
The research result, published in the Biotechnology and Bioengineering journal, proviDrdes a renewable alternative to the traditional process using fossil fuels.
Currently the production of putrescine on an industrial scale relies on chemical synthesis, which requires non-renewable petrochemicals and expensive catalyst systems. This process is highly toxic and flammable with potentially severe repercussions for both the environment and human health.
"For the first time we have developed a metabolically engineered E. coli strain that efficiently produces putrescine," said Professor Lee. "The development of a bio-refinery for chemicals and materials is very important in a world where dependency on fossil fuels is an increasing concern."
The team developed a strain of E.coli capable of producing putrescine through metabolic engineering. This is where a cell"s metabolic and regulatory networks are enhanced in order to increase production of a needed material.
First the team weakened or deleted competing metabolic pathways within the E. coli strain before deleting pathways which cause putrescine degradation. They also amplified the crucial enzyme Spec C, which converts the chemical ornithine into putrescine. Finally the putrescine exporter, which allows excretion of intracellularly made putrescine, was engineered while a global regulator was engineered to further increase the concentration of putrescine. The final result of this process was an engineered E.coli strain which produced 24.2 g of putrescine per litre.
However, as it was believed that putrescine is toxic to microorganisms the team had to study putrescine tolerance in E.coli before it could be engineered to overproduce the chemical to the levels needed for industrial production.
The results revealed that E. coli can tolerate at least 0.5 M of putrescine, which is tenfold higher than the usual concentration in the cell. This level of tolerance was an important surprise as it means that E. coli can be engineered to overproduce putrescine to industrially competitive levels.
"The previously expected toxicity of putrescine may explain why its microbial production has been overlooked," said Lee. "Now a metabolically engineered E. coli strain has been developed which is capable of efficiently producing putrescine using renewable methods to an industrial level. This metabolic engineering framework should be useful for developing metabolically engineered microorganisms for the efficient production of other chemicals from renewable resources," he added.
2009.09.01 View 14985 -
Transparent Antenna for Automobile Developed
A research team led by Prof. Jae-Woo Park of the School of Electrical Engineering & Computer Science, KAIST, developed a transparent antenna for the next-generation automobiles, university authorities said on Monday (Aug. 17).
The development was made possible through joint researches with the Hyundai-Kia Automotive Group; Winncom, a car antenna manufacturer; and a group of researchers led by Han-Ki Kim of the Department of Display Materials Engineering at Kyung Hee University in Seoul.
The transparent antennas were developed in two kinds -- one for the HSDPA (High-Speed Downlink Packet Access), a new protocol for mobile telephone data transmission, and the other for transmitting and receiving radio wave for emergency call.
Using the transparent electrically conductive film formation technology, the transparent antennas are to be mounted on the windshield of a vehicle.
"The development of transparent antenna represents a step forward for the advancement of the next-generation automotive electronic technology," said Seong-woo Kim, a senior researcher at the Hyundai-Kia Group.
2009.08.18 View 14498 -
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 21227 -
Prof. Chong Unveils New Human Movement Model
A KAIST research team headed by Prof. Song Chong of the School of Electrical Engineering and Computer Science has developed a new statistical model that simulates human mobility patterns, mimicking the way people move over the course of a day, a month or longer, university sources said on Tuesday (May 12).
The model, developed in collaboration with scientists at North Carolina State University, is the first to represent the regular movement patterns of humans using statistical data.
The model has a variety of potential uses, ranging from land use planning to public health studies on epidemic disease.
The researchers gave global positioning system (GPS) devices to approximately 100 volunteers at five locations in the U.S. and South Korea and tracked the participants" movements over time. By tracing the points where the study participants stopped, and their movement trajectories, researchers were able to determine patterns of mobility behavior.
The researchers were then able to emulate these fundamental statistical properties of human mobility into a model that could be used to represent the regular daily movement of humans. The model, called Self-similar Least Action Walk (SLAW), will have a wide array of practical applications.
The research, "SLAW: A Mobility Model for Human Walks," was presented on April 20 at the 28th IEEE Conference on Computer Communications in Rio de Janeiro, Brazil. The National Science Foundation of the U.S. funded the research.
2009.05.13 View 14605 -
KAIST Professor Unveils New Method of Manufacturing Complex Nano-wire
A KAIST research team led by Prof. Sang-Ouk Kim of the Department of Materials Science and Engineering has discovered a new nanowire manufacturing method, university sources said on Monday (May 11).
The KAIST researchers successfully demonstrated soft graphoepitaxy of block copolymer assembly as a facile, scalable nanolithography for highly ordered sub-30-nm scale features. Graphoepitaxy is a new technique that uses artificial surface relief structure to induce crystallographic orientation in thin films.
Various morphologies of hierarchical block copolymer assembly were achieved by means of disposable topographic confinement of photoresist pattern. Unlike usual graphoepitaxy, soft graphoepitaxy generates the functional nanostrutures of metal and semiconductor nanowire arrays without any trace of structure-directing topographic pattern.
The discovery was featured in the May 7 edition of Nano-Letters. Application has been made for the domestic patent of the new method.
The new method is expected to be advantageous for multi-layer overlay processing required for complex device architecture, the sources said.
2009.05.12 View 11315 -
KAIST Research Team Discovers Process for Rapid Growth of N-Doped CNT Arrays
A team of scientists led by Profs. Sang-Ouk Kim, Won-Jong Lee and Duck-Hyun Lee of the Department of Materials Science and Engineering has found a straightforward process for rapid growth of wall-number selected, nitrogen-doped carbon nanotube (CNT) arrays, university officials said on Monday (March 16).
KAIST researchers prepared highly uniform nanopatterned iron catalyst arrays by tilted deposition through block copolymer nanotemplates. This remarkably fast growth of highly uniform N-doped CNTs, whose material properties and chemical functionalizability are reinforced by N-doping, offers a new area of a large-scale nanofabrication, potentially useful for diverse nano-devices.
Carbon nanotubes (CNTs) are of broad technical interest in electronics, photonics, energy devices, and other applications. However, establishing a straightforward process for mass production of uniform CNTs with desired structure and properties has been a long-standing challenge.
In particular, it was strongly desired to precisely control the numbers of walls and diameter of CNTs, which are decisive parameters for the physical properties of CNTs. In this respect, the preparation of monodisperse catalyst array having a narrow size distribution is generally considered an effective pathway to produce well-defined CNTs, since the number of walls and diameter of the produced CNTs are closely related to the catalyst size.
The finding was featured in the March 13 edition of Nano Letters, a leading journal in the nano technology field.
2009.03.20 View 14698