Kaist

KAIST Discloses the Formation of Burning Ice in Oc..

(from left: Professor Tae-Hyuk Kwon and PhD candidate Taehyung Park) ?A KAIST research team has identified the formation of natural gas hydrates, so-called flammable ice, formed in oceans. Professor Tae-Hyuk Kwon from the Department of Civil & Environmental Engineering and his team found that clay minerals in oceanic clay-rich sedimentary deposits promote formation of gas hydrates and proposed the principle of gas hydrate formation in the clayey sedimentary layers. Gas hydrates are ice-like crystalline structures composed of hydrogen-bonded water molecules encapsulating gas molecules. They are also known as burning ice. Their deposits are so huge that they gain attention for alternative energy. Conventionally, it was believed that formation of gas hydrates is limited in clay sedimentary deposits; however, unexpected abundance of natural gas hydrates in oceanic clay-rich sedimentary deposits raised the issue of how they formed. The surfaces of natural clay minerals are negatively charged and, thus, unavoidably generate physicochemical interactions between clay and water. Such clay-water interactions have a critical role in the occurrence of natural gas hydrates in clay-rich sedimentary formations. However, there has been experimental difficulty in analyzing hydrate formation because of the cations contained in clay particles, which balance the clay surface charges. Therefore, clay particles inevitably release the cations when mixed with water, which complicates the interpretation of experimental results. To overcome this limitation, the team polarized water molecules with an electric field and monitored the induction times of water molecules forming gas hydrates. They found that the 10 kV/m of electric field promoted gas hydrate nucleation under certain conditions rather than slowing it down, due to the partial breakage of the hydrogen bonded water clusters and the lowered thermal energy of water molecules. Professor Kwon said, “Through this research, we gained better insight into the origin of gas hydrates occurrence in clay-rich sedimentary deposits. In the near future, we will soon be able to commercially produce methane gas from natural gas hydrate deposits.” This research, led by PhD candidate Taehyung Park, was published online in Environmental Science and Technology on February 3. (doi: 10.1021/acs.est.7b05477) Figure 1. Formation of gas hydrates with water molecules Figure 2. Enhancement and inhibition of gas hydrates

Printed Thermo-Plasmonic Heat Patterns for Neurolo..

(Professor Nam and Dr. Kang, right) A KAIST team presented a highly customizable neural stimulation method. The research team developed a technology that can print the heat pattern on a micron scale to enable the control of biological activities remotely. The researchers integrated a precision inkjet printing technology with bio-functional thermo-plasmonic nanoparticles to achieve a ‘selective nano-photothermal neural stimulation method.’ The research team of Professor Yoonkey Nam at the Department of Bio and Brain Engineering expects this will serve as an enabling technology for personalized precision neuromodulation therapy for patients with neurological disorders. The nano-photothermal neural stimulation method uses the thermo-plasmonic effect of metal nanoparticles to modulate the activities of neuronal networks. With the thermo-plasmonic effect, metal nanoparticles can absorb specific wavelength of illuminated light to efficiently generate localized heat. The research team discovered the inhibitory behavior of spontaneous activities of neurons upon photothermal stimulation four years ago. Since then, they have developed this technology to control hyperactive behaviors of neurons and neural circuits, which is often found in neurological disorders such as epilepsy. In order to overcome the limitation on the spatial selectivity and resolution of the previously developed nano-photothermal method, the team adopted an inkjet printing technology to micro pattern the plasmonic nanoparticles (a few tens of microns), and successfully demonstrated that the nano-photothermal stimulation can be selectively applied according to the printed patterns. The researchers applied a polyelectrolyte layer-by-layer coating method to printing substrates in a way to improve the pattern fidelity and achieve the uniform assembly of nanoparticles. The electrostatic attraction between the printed nanoparticles and the coated printing substrate also helped the stability of the attached nanoparticles. Because the polyelectrolyte coating is biocompatible, biological experiments including cell culture are possible with the technology developed in this work. Using printed gold nanorod particles in a few tens of microns resolution over a several centimeters area, the researchers showed that highly complex heat patterns can be precisely formed upon light illumination according to the printing image. Lastly, the team confirmed that the printed heat patterns can selectively and instantaneously inhibit the activities of cultured hippocampal neurons upon near-infrared light illumination. Because the printing process is applicable to thin and flexible substrates, the technology can be easily applied to implantable neurological disorder treatment devices and wearable devices. By selectively applying the heat patterns to only the desired cellular areas, customized and personalized photothermal neuromodulation therapy can be applied to patients. “The fact that any desired heat patterns can be simply ‘printed’ anywhere broadens the applicability of this technology in many engineering fields. In bioengineering, it can be applied to neural interfaces using light and heat to modulate physiological functions. As another engineering application, for example, printed heat patterns can be used as a new concept of anti-counterfeit applications,” said the principal investigator, Yoonkey Nam at KAIST. This work, led mainly by Dr. Hongki Kang, was published in ACS Nano on February 5th 2018.

KAIST Develops IoT Platform for Food Safety

A research team led by the KAIST Auto-ID Labs developed a GS1 international standard-based IoTs infrastructure platform dubbed Oliot (Open Language of Internet of Things). This platform will be applied to Wanju Local Food, the nation’s largest cooperative, and will be in operation from April 5. A total of eleven organizations participated in the development of Oliot, with KAIST as the center. This consortium is based on the GS1 international standard-based Oliot platform, which allows collecting and sharing data along the entire process of agrifood from production to processing, distribution, and consumption. It aims at increasing farm incomes and establishing a global ecosystem of domestic agriculture and stockbreeding that provides safe food. Wanju Local Food is now the world’s first local food co-op with a traceability system from the initial stage of production planning to end sales based on GS1 international standards, which will ensure food safety. KAIST has been sharing Oliot data in order to apply it to industries around the world. As of April 2018, approximately 900 enterprises and developers from more than 100 countries have downloaded it. Professor Daeyoung Kim from the School of Computing, who is also Research Director of Auto-ID Labs said, “We are planning to disseminate Oliot to local food cooperatives throughout the nation. We will also cooperate with other countries, like China, Holland, and Hong Kong to create a better ecosystem for the global food industry. “We are currently collaborating with related business to converge Oliot with AI or blockchain technology that can be applied to various services, such as healthcare and smart factories. Its tangible outcome will be revealed soon,” he added. Auto-ID Labs are a global research consortium of six academic institutions that research and develop new technologies for advancing global commerce, partnering with GS1 (Global Standard 1), a non-profit organization that established standards for global commerce such as introducing barcodes to the retail industry. The Auto-ID Labs include MIT, University of Cambridge, Keio University, Fudan University, ETH Zurich/University of St. Gallen, and KAIST. The consortium was supported by the Ministry of Science and ICT as well as the Institute for Information and Communications Technology Promotion for three years from 2015. The launching of Oliot at Wanju Local Food will be held on April 5.

Professor Emeritus Jung Ki Park Won the IBA Techno..

(Professor Emeritus Jung Ki Park) Professor Emeritus Jung Ki Park from the Department of Chemical and Biomolecular Engineering received the IBA Technology Award from the International Battery Association (IBA). IBA 2018 was held from March 11 to 16 on Jeju Island, which was the first time it was hosted in Korea. The conference was an excellent opportunity to let the world know the level of the Korean rechargeable battery industry and its technology. Professor Park delivered his keynote speech titled Advances in Lithium Batteries in Korea at the conference and received the IBA Technology Award as the first Korean recipient. ?Professor Park is a world-renowned scholar who was a groundbreaker in the rechargeable battery industry. He was recognized by the IBA Award Committee for his contributions carrying out research and development, fostering competent people, and enhancing the lithium rechargeable battery industry in Korea over the last 30 years. Professor Park said, “It is my great honor to receive this award, which is the best international award in the field of rechargeable batteries. I would like to share this with my colleagues and students. As competition in the rechargeable industry intensifies, systemic cooperation among industries, academia, and government is needed for the continued development of the battery industry in Korea.

Seong-Tae Kim Wins Robert-Wagner All-Conference Be..

(Ph.D. candidate Seong-Tae Kim) Ph.D. candidate Seong-Tae Kim from the School of Electrical Engineering won the Robert Wagner All-Conference Best Student Paper Award during the 2018 International Society for Optics and Photonics (SPIE) Medical Imaging Conference, which was held in Houston last month. Kim, supervised by Professor Yong Man Ro, received the award for his paper in the category of computer-aided diagnosis. His paper, titled “ICADx: Interpretable Computer-Aided Diagnosis of Breast Masses”, was selected as the best paper out of 900 submissions. The conference selects the best paper in nine different categories. His research provides new insights on diagnostic technology to detect breast cancer powered by deep learning.

Recognizing Seven Different Face Emotions on a Mob..

(Professor Hoi-Jun Yoo) A KAIST research team succeeded in achieving face emotion recognition on a mobile platform by developing an AI semiconductor IC that processes two neural networks on a single chip. Professor Hoi-Jun Yoo and his team (Primary researcher: Jinmook Lee Ph. D. student) from the School of Electrical Engineering developed a unified deep neural network processing unit (UNPU). Deep learning is a technology for machine learning based on artificial neural networks, which allows a computer to learn by itself, just like a human. The developed chip adjusts the weight precision (from 1 bit to 16 bit) of a neural network inside of the semiconductor in order to optimize energy efficiency and accuracy. With a single chip, it can process a convolutional neural network (CNN) and recurrent neural network (RNN) simultaneously. CNN is used for categorizing and recognizing images while RNN is for action recognition and speech recognition, such as time-series information. Moreover, it enables an adjustment in energy efficiency and accuracy dynamically while recognizing objects. To realize mobile AI technology, it needs to process high-speed operations with low energy, otherwise the battery can run out quickly due to processing massive amounts of information at once. According to the team, this chip has better operation performance compared to world-class level mobile AI chips such as Google TPU. The energy efficiency of the new chip is 4 times higher than the TPU. In order to demonstrate its high performance, the team installed UNPU in a smartphone to facilitate automatic face emotion recognition on the smartphone. This system displays a user’s emotions in real time. The research results for this system were presented at the 2018 International Solid-State Circuits Conference (ISSCC) in San Francisco on February 13. Professor Yoo said, “We have developed a semiconductor that accelerates with low power requirements in order to realize AI on mobile platforms. We are hoping that this technology will be applied in various areas, such as object recognition, emotion recognition, action recognition, and automatic translation. Within one year, we will commercialize this technology.”

Aqueous Storage Device Needs Only 20 Seconds to Go

(from left: PhD candidate Il Woo Ock and Professor Jeung Ku Kang) A KAIST research team developed a new hybrid energy storage device that can be charged in less than half a minute. It employs aqueous electrolytes instead of flammable organic solvents, so it is both environmentally friendly and safe. It also facilitates a boosting charge with high energy density, which makes it suitable for portable electronic devices. Professor Jeung Ku Kang and his team from the Graduate School of Energy, Environment, Water, and Sustainability developed this hybrid energy storage with high energy and power densities along over a long cycle life by assembling fibre-like polymer chain anodes and sub-nanoscale metal oxide cathodes on graphene. Conventional aqueous electrolyte-based energy storage devices have a limitation for boosting charges and high energy density due to low driving voltage and a shortage of anode materials. Energy storage device capacity is determined by the two electrodes, and the balance between cathode and anode leads to high stability. In general, two electrodes show differences in electrical properties and differ in ion storage mechanism processes, resulting in poor storage and stability from the imbalance. The research team came up with new structures and materials to facilitate rapid speed in energy exchange on the surfaces of the electrodes and minimize the energy loss between the two electrodes. The team made anodes with graphene-based polymer chain materials. The web-like structure of graphene leads to a high surface area, thereby allowing higher capacitance. For cathode materials, the team used metal oxide in sub-nanoscale structures to elevate atom-by-ion redox reactions. This method realized higher energy density and faster energy exchange while minimizing energy loss. The developed device can be charged within 20 to 30 seconds using a low-power charging system, such as a USB switching charger or a flexible photovoltaic cell. The developed aqueous hybrid energy device shows more than 100-fold higher power density compared to conventional aqueous batteries and can be rapidly recharged. Further, the device showed high stability with its capacity maintained at 100％ at a high charge/discharge current. Professor Kang said, “This eco-friendly technology can be easily manufactured and is highly applicable. In particular, its high capacity and high stability, compared to existing technologies, could contribute to the commercialization of aqueous capacitors. The device can be rapidly charged using a low-power charging system, and thus can be applied to portable electronic device.” This research, led by a PhD candidate Il Woo Ock, was published in Advanced Energy Materials on January 15. Figure 1. Switching wearable LED kit with two AHCs in series charged by a flexible photovoltaic cell ?Figure 2. Schematic diagram for aqueous hybrid capacitors Figure 3. TEM images of anode and cathode

KAIST, First to Win the Cube Satellite Competition

?Professor Hyochoong Bang from the Department of Aerospace Engineering and his team received the Minister of Science and ICT Award at the 1st Cube Satellite Competition. The team actually participated in the competition in 2012, but it took several years for the awarding ceremony since it took years for the satellites to be designed, produced, and launched. The KAIST team successfully developed a cube satellite, named ‘Little Intelligent Nanosatellite of KAIST (LINK)’ and completed its launch in April 2017. LINK (size: 20cmx10cmx10cm, weight: 2kg) mounted mass spectrometry and Langmuir probe for Earth observation. The Langmuir probe was developed by Professor Kyoung Wook Min from the Department of Physics, KAIST. Yeerang Lim, a PhD student from the Department of Aerospace Engineering said, “I still remember the feeling that I had on the day when LINK launched into orbit and sent back signals. I hope that space exploration is not something far away but attainable for us in near future.”