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Highly Deformable Piezoelectric Nanotruss for Tactile Electronics
With the importance of non-contact environments growing due to COVID-19, tactile electronic devices using haptic technology are gaining traction as new mediums of communication.
Haptic technology is being applied in a wide array of fields such as robotics or interactive displays. haptic gloves are being used for augmented information communication technology. Efficient piezoelectric materials that can convert various mechanical stimuli into electrical signals and vice versa are a prerequisite for advancing high-performing haptic technology.
A research team led by Professor Seungbum Hong confirmed the potential of tactile devices by developing ceramic piezoelectric materials that are three times more deformable. For the fabrication of highly deformable nanomaterials, the research team built a zinc oxide hollow nanostructure using proximity field nanopatterning and atomic layered deposition. The piezoelectric coefficient was measured to be approximately 9.2 pm/V and the nanopillar compression test showed an elastic strain limit of approximately 10%, which is more than three times greater than that of the bulk zinc oxide one.
Piezoelectric ceramics have a high piezoelectric coefficient with a low elastic strain limit, whereas the opposite is true for piezoelectric polymers. Therefore, it has been very challenging to obtain good performance in both high piezoelectric coefficients as well as high elastic strain limits. To break the elastic limit of piezoelectric ceramics, the research team introduced a 3D truss-like hollow nanostructure with nanometer-scale thin walls.
According to the Griffith criterion, the fracture strength of a material is inversely proportional to the square root of the preexisting flaw size. However, a large flaw is less likely to occur in a small structure, which, in turn, enhances the strength of the material. Therefore, implementing the form of a 3D truss-like hollow nanostructure with nanometer-scale thin walls can extend the elastic limit of the material. Furthermore, a monolithic 3D structure can withstand large strains in all directions while simultaneously preventing the loss from the bottleneck. Previously, the fracture property of piezoelectric ceramic materials was difficult to control, owing to the large variance in crack sizes. However, the research team structurally limited the crack sizes to manage the fracture properties.
Professor Hong’s results demonstrate the potential for the development of highly deformable ceramic piezoelectric materials by improving the elastic limit using a 3D hollow nanostructure. Since zinc oxide has a relatively low piezoelectric coefficient compared to other piezoelectric ceramic materials, applying the proposed structure to such components promised better results in terms of the piezoelectric activity.
“With the advent of the non-contact era, the importance of emotional communication is increasing. Through the development of novel tactile interaction technologies, in addition to the current visual and auditory communication, mankind will enter a new era where they can communicate with anyone using all five senses regardless of location as if they are with them in person,” Professor Hong said.
“While additional research must be conducted to realize the application of the proposed designs for haptic enhancement devices, this study holds high value in that it resolves one of the most challenging issues in the use of piezoelectric ceramics, specifically opening new possibilities for their application by overcoming their mechanical constraints.
The research was reported in Nano Energy and supported by the Ministry of Science and ICT, the Korea Research Foundation, and the KAIST Global Singularity Research Project.
-Profile: Professor Seungbum Hong
seungbum@kaist.ac.kr
http://mii.kaist.ac.kr/
Department of Materials Science and Engineering
KAIST
2021.02.02 View 9140 -
Top University Leaders Urge Innovation for the Post-COVID Era at the KAIST Summit
- Presidents of KAIST, MIT, Tokyo Tech, and Northwestern to define new roles and responsibilities of universities for the post-COVID and 4IR eras during an online summit in celebration of KAIST’s 50th anniversary. -
Universities are facing ever-mounting pressure to address impacts brought on by COVID-19 and the emerging technologies of the Fourth Industrial Revolution (4IR).
Presidents from MIT, Tokyo Tech, and Northwestern University will join the KAIST Summit to explore new directions for higher education during the post-COVID era intertwined with the 4IR. They agree that addressing these dual challenges requires pushing for innovations to rebuild the competitive edges of universities.
This summit is one of KAIST’s series of events to envision the future of KAIST and higher education in celebration of its 50th anniversary. The online summit will be live streamed on KAIST’s official YouTube channel (https://www.youtube.com/c/KAISTofficial) on February 3, 2021, from 10 a.m. to 12:00 p.m. Korean time (February 2, 7:00-9:00 p.m. CST and 8:00-10:00 p.m. EST, respectively).
The KAIST Summit titled “The Roles and Responsibilities of Universities in a Global Crisis” will discuss a range of issues affecting many aspects of universities in the coming decades.
“This summit will allow us to measure the level of risk that universities face today and will face in the future. Although there will be varying views on what a post-COVID world might look like, one thing for sure is that universities cannot go back to the way they used to exist and operate. Moreover, the 4IR continues to infiltrate and shake up our daily lives. Changes are inevitable, and universities must pursue bold and innovative responses to remain sustainable and relevant to society,” said KAIST President Sung-Chul Shin on the background of hosting the event.
The keynote speakers include KAIST President Shin, MIT President L. Rafael Reif, Tokyo Tech President Kazuya Masu, and Northwestern University President Morton Schapiro. After the keynote speech session, the speakers will take part in a panel discussion on three topics: “The Digital Divide,” “Emerging Challenges in AI,” and “Social Entrepreneurship and University-Industry Collaboration.” A Q&A session with an online audience consisting of KAIST faculty, staff, and students as well as high school students across the nation will follow shortly afterwards.
President Reif of MIT will congratulate KAIST on its successful 50-year journey from meager beginnings to achieving its current status as one of the finest global universities in science and technology. Then he will give a talk titled “Universities as Engines of Change” to present how universities have played a critical role in advancing solutions to humanity’s most urgent problems.
President Masu of Tokyo Tech will stress the importance of universities’ continuous dialogue with society as drivers of innovation. In his speech titled “Designing Our Future—Tokyo Tech DLab’s Approach,” he will introduce the activities of Tokyo Tech’s Laboratory for Design of Social Innovation in Global Networks (DLab) and explain how DLab collaborates for the future with members of society.
President Schapiro of Northwestern University will speak about how universities might incorporate the lessons they learned in dealing with COVID-19 to improve their research, teaching, and public service in the post-pandemic era. He will also look into issues arising from changing labor market needs associated with the 4IR and the aftermath of COVID-19 in his talk titled “The University in the ‘New Normal.’”
Finally, President Shin of KAIST will deliver a presentation on the “Visions & Innovations for the Next Dream of KAIST.” He will reflect on the remarkable track record from KAIST’s first 50 years and how it has contributed significantly to the rapid growth of Korea as a hi-tech powerhouse. Furthermore, he will elaborate on a new vision for the development of KAIST over the next 50 years and roll out a set of strategic innovation plans in the five areas of education, research, technology commercialization, globalization, and future strategy.
In the panel discussion, the four presidents will dive into a more intense conversation on such topics as universities’ role in bridging the increasing digital divide through their research, education, and international cooperation; the socioeconomic implications and ethical challenges of the fast deployment of AI and robotics; 4IR disruptions that will transform higher education; ways to foster social innovation and youth entrepreneurship; and how to build university-industry cooperation.
More information on KAIST’s 50th anniversary celebrations can be found on its special celebratory website at https://50.kaist.ac.kr/eng/. The official anniversary ceremony is scheduled for February 16, 2021, from 10 a.m. Korean time, and live-streaming will also be made available on KAIST’s official YouTube channel at https://www.youtube.com/c/KAISTofficial.
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2021.02.01 View 12586 -
Professor Bumjoon Kim Named Scientist of the Month
Professor Bumjoon Kim from the Department of Chemical and Biomolecular Engineering won January’s Scientist of the Month Award presented by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF) on January 6. Professor Kim also received 10 million won in prize money.
Professor Kim was recognized for his research in the field of fuel cells. Since the first paper on fuel cells was published in 1839 by the German chemist Friedrich Schonbein, there has been an increase in the number of fields in which fuel cells are used, including national defense, aerospace engineering, and autonomous vehicles.
Professor Kim developed carbonized block copolymer particles with high durability and a high-performance fuel cell. Block copolymers are two different polymers cross-linked into a chain structure. Various nanostructures can be made effectively by using the attractive and repulsive forces between the chains.
Professor Kim used the membrane emulsification technique, employing a high-performance separation membrane to develop a platform that makes the mass production of highly durable carbonized particles possible, which he then used to develop high-performance energy devices like fuel cells.
The carbonized particles designed by Professor Kim and his research team were used to create the world’s more durable fuel cells that boast outstanding performance while using only five percent of the costly platinum needed for existing commercialized products.
The team’s research results were published in the Journal of the American Chemical Society and Energy Environmental Science in May and July of last year.
“We have developed a fuel cell that ticks all the boxes including performance, durability, and cost,” said Professor Kim. “Related techniques will not be limited to fuel cells, but could also be applied to the development of various energy devices like solar cells and secondary cells,” he added.
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2021.01.22 View 9754 -
Extremely Stable Perovskite Nanoparticles Films for Next-Generation Displays
Researchers have reported an extremely stable cross-linked perovskite nanoparticle that maintains a high photoluminescence quantum yield (PLQY) for 1.5 years in air and harsh liquid environments. This stable material’s design strategies, which addressed one of the most critical problems limiting their practical application, provide a breakthrough for the commercialization of perovskite nanoparticles in next-generation displays and bio-related applications.
According to the research team led by Professor Byeong-Soo Bae, their development can survive in severe environments such as water, various polar solvents, and high temperature with high humidity without additional encapsulation. This development is expected to enable perovskite nanoparticles to be applied to high color purity display applications as a practical color converting material. This result was published as the inside front cover article in Advanced Materials.
Perovskites, which consist of organics, metals, and halogen elements, have emerged as key elements in various optoelectronic applications. The power conversion efficiency of photovoltaic cells based on perovskites light absorbers has been rapidly increased. Perovskites are also great promise as a light emitter in display applications because of their low material cost, facile wavelength tunability, high (PLQY), very narrow emission band width, and wider color gamut than inorganic semiconducting nanocrystals and organic emitters. Thanks to these advantages, perovskites have been identified as a key color-converting material for next-generation high color-purity displays. In particular, perovskites are the only luminescence material that meets Rec. 2020 which is a new color standard in display industry.
However, perovskites are very unstable against heat, moisture, and light, which makes them almost impossible to use in practical applications. To solve these problems, many researchers have attempted to physically prevent perovskites from coming into contact with water molecules by passivating the perovskite grain and nanoparticle surfaces with organic ligands or inorganic shell materials, or by fabricating perovskite-polymer nanocomposites. These methods require complex processes and have limited stability in ambient air and water. Furthermore, stable perovskite nanoparticles in the various chemical environments and high temperatures with high humidity have not been reported yet.
The research team in collaboration with Seoul National University develops siloxane-encapsulated perovskite nanoparticle composite films. Here, perovskite nanoparticles are chemically crosslinked with thermally stable siloxane molecules, thereby significantly improving the stability of the perovskite nanoparticles without the need for any additional protecting layer.
Siloxane-encapsulated perovskite nanoparticle composite films exhibited a high PLQY (> 70%) value, which can be maintained over 600 days in water, various chemicals (alcohol, strong acidic and basic solutions), and high temperatures with high humidity (85℃/85%). The research team investigated the mechanisms impacting the chemical crosslinking and water molecule-induced stabilization of perovskite nanoparticles through various photo-physical analysis and density-functional theory calculation.
The research team confirmed that displays based on their siloxane-perovskite nanoparticle composite films exhibited higher PLQY and a wider color gamut than those of Cd-based quantum dots and demonstrated perfect color converting properties on commercial mobile phone screens. Unlike what was commonly believed in the halide perovskite field, the composite films showed excellent bio-compatibility because the siloxane matrix prevents the toxicity of Pb in perovskite nanoparticle.
By using this technology, the instability of perovskite materials, which is the biggest challenge for practical applications, is greatly improved through simple encapsulation method.
“Perovskite nanoparticle is the only photoluminescent material that can meet the next generation display color standard. Nevertheless, there has been reluctant to commercialize it due to its moisture vulnerability. The newly developed siloxane encapsulation technology will trigger more research on perovskite nanoparticles as color conversion materials and will accelerate early commercialization,” Professor Bae said.
This work was supported by the Wearable Platform Materials Technology Center (WMC) of the Engineering Research Center (ERC) Project, and the Leadership Research Program funded by the National Research Foundation of Korea.
-Publication:
Junho Jang, Young-Hoon Kim, Sunjoon Park, Dongsuk Yoo, Hyunjin Cho, Jinhyeong Jang, Han Beom Jeong, Hyunhwan Lee, Jong Min Yuk, Chan Beum Park, Duk Young Jeon, Yong-Hyun Kim, Byeong-Soo Bae, and Tae-Woo Lee. “Extremely Stable Luminescent Crosslinked Perovskite Nanoparticles under Harsh Environments over 1.5 Years” Advanced Materials, 2020, 2005255. https://doi.org/10.1002/adma.202005255.
Link to download the full-text paper:
https://onlinelibrary.wiley.com/doi/10.1002/adma.202005255
-Profile: Prof. Byeong-Soo Bae (Corresponding author)
bsbae@kaist.ac.kr
Lab. of Optical Materials & Coating
Department of Materials Science and Engineering
Korea Advanced Institute of Science and Technology (KAIST)
2020.12.29 View 11046 -
Electrosprayed Micro Droplets Help Kill Bacteria and Viruses
With COVID-19 raging around the globe, researchers are doubling down on methods for developing diverse antimicrobial technologies that could be effective in killing a virus, but harmless to humans and the environment.
A recent study by a KAIST research team will be one of the responses to such efforts. Professor Seung Seob Lee and Dr. Ji-hun Jeong from the Department of Mechanical Engineering developed a harmless air sterilization prototype featuring electrosprayed water from a polymer micro-nozzle array. This study is one of the projects being supported by the KAIST New Deal R&D Initiative in response to COVID-19. Their study was reported in Polymer.
The electrosprayed microdroplets encapsulate reactive oxygen species such as hydroxyl radicals, superoxides that are known to have an antimicrobial function. The encapsulation prolongs the life of reactive oxygen species, which enable the droplets to perform their antimicrobial function effectively. Prior research has already proven the antimicrobial and encapsulation effects of electrosprayed droplets.
Despite its potential for antimicrobial applications, electrosprayed water generally operates under an electrical discharge condition, which can generate ozone. The inhalation of ozone is known to cause damage to the respiratory system of humans. Another technical barrier for electrospraying is the low flow rate problem. Since electrospraying exhibits the dependence of droplet size on the flow rate, there is a limit for the amount of water microdroplets a single nozzle can produce.
With this in mind, the research team developed a dielectric polymer micro-nozzle array to perform the multiplexed electrospraying of water without electrical discharge. The polymer micro-nozzle array was fabricated using the MEMS (Micro Electro-Mechanical System) process. According to the research team, the nozzle can carry five to 19 micro-nozzles depending on the required application.
The high aspect ratio of the micro-nozzle and an in-plane extractor were proposed to concentrate the electric field at the tip of the micro-nozzle, which prevents the electrical discharge caused by the high surface tension of water. A micro-pillar array with a hydrophobic coating around the micro-nozzle was also proposed to prevent the wetting of the micro-nozzle array.
The polymer micro-nozzle array performed in steady cone jet mode without electrical discharge as confirmed by high-speed imaging and nanosecond pulsed imaging. The water microdroplets were measured to be in the range of six to 10 μm and displayed an antimicrobial effect on Escherichia coli and Staphylococcus aureus.
Professor Lee said, “We believe that this research can be applied to air conditioning products in areas that require antimicrobial and humidifying functions.”
Publication:
Jeong, J. H., et al. (2020) Polymer micro-atomizer for water electrospray in the cone jet mode. Polymer. Vol. No. 194, 122405. Available online at https://doi.org/10.1016/j.polymer.2020.122405
Profile: Seung Seob Lee, Ph.D.
sslee97@kaist.ac.kr
http://mmst.kaist.ac.kr/
Professor
Department of Mechanical Engineering (ME)
Korea Advanced Institute of Science and Technology (KAIST)
https://www.kaist.ac.kr
Daejeon 34141, Korea
Profile: Ji-hun Jeong, Ph.D.
jiuni6022@kaist.ac.kr
Postdoctoral researcher
Department of Mechanical Engineering (ME)
Korea Advanced Institute of Science and Technology (KAIST)
https://www.kaist.ac.kr
Daejeon 34141, Korea
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2020.12.21 View 10900 -
Researchers Report Longest-lived Aqueous Flow Batteries
New technology to overcome the life limit of next-generation water-cell batteries
A research team led by Professor Hee-Tak Kim from the Department of Chemical and Biomolecular Engineering has developed water-based zinc/bromine redox flow batteries (ZBBs) with the best life expectancy among all the redox flow batteries reported by identifying and solving the deterioration issue with zinc electrodes.
Professor Kim, head of the Advanced Battery Center at KAIST's Nano-fusion Research Institute, said, "We presented a new technology to overcome the life limit of next-generation water-cell batteries. Not only is it cheaper than conventional lithium-ion batteries, but it can contribute to the expansion of renewable energy and the safe supply of energy storage systems that can run with more than 80 percent energy efficiency."
ZBBs were found to have stable life spans of more than 5,000 cycles, even at a high current density of 100 mA/cm2. It was also confirmed that it represented the highest output and life expectancy compared to Redox flow batteries (RFBs) reported worldwide, which use other redox couples such as zinc-bromine, zinc-iodine, zinc-iron, and vanadium.
Recently, more attention has been focused on energy storage system (ESS) that can improve energy utilization efficiency by storing new and late-night power in large quantities and supplying it to the grid if necessary to supplement the intermittent nature of renewable energy and meet peak power demand.
However, lithium-ion batteries (LIBs), which are currently the core technology of ESSs, have been criticized for not being suitable for ESSs, which store large amounts of electricity due to their inherent risk of ignition and fire. In fact, a total of 33 cases of ESSs using LIBs in Korea had fire accidents, and 35% of all ESS facilities were shut down. This is estimated to have resulted in more than 700 billion won in losses.
As a result, water-based RFBs have drawn great attention. In particular, ZBBs that use ultra-low-cost bromide (ZnBr2) as an active material have been developed for ESSs since the 1970s, with their advantages of high cell voltage, high energy density, and low price compared to other RFBs. Until now, however, the commercialization of ZBBs has been delayed due to the short life span caused by the zinc electrodes. In particular, the uneven "dendrite" growth behavior of zinc metals during the charging and discharging process leads to internal short circuits in the battery which shorten its life.
The research team noted that self-aggregation occurs through the surface diffusion of zinc nuclei on the carbon electrode surface with low surface energy, and determined that self-aggregation was the main cause of zinc dendrite formation through quantum mechanics-based computer simulations and transmission electron microscopy. Furthermore, it was found that the surface diffusion of the zinc nuclei was inhibited in certain carbon fault structures so that dendrites were not produced.
Single vacancy defect, where one carbon atom is removed, exchanges zinc nuclei and electrons, and is strongly coupled, thus inhibiting surface diffusion and enabling uniform nuclear production/growth. The research team applied carbon electrodes with high density fault structure to ZBBs, achieving life characteristics of more than 5,000 cycles at a high charge current density (100 mA/cm2), which is 30 times that of LIBs.
This ESS technology, which can supply eco-friendly electric energy such as renewable energy to the private sector through technology that can drive safe and cheap redox flow batteries for long life, is expected to draw attention once again.
Publication:
Ju-Hyuk Lee, Riyul Kim, Soohyun Kim, Jiyun Heo, Hyeokjin Kwon, Jung Hoon Yang, and Hee-Tak Kim. 2020. Dendrite-free Zn electrodeposition triggered by interatomic orbital hybridization of Zn and single vacancy carbon defects for aqueous Zn-based flow batteries. Energy and Environmental Science, 2020, 13, 2839-2848.
Link to download the full-text paper:http://xlink.rsc.org/?DOI=D0EE00723D
Profile: Prof. Hee-Tak Kimheetak.kim@kaist.ac.krhttp://eed.kaist.ac.krAssociate ProfessorDepartment of Chemical & Biomolecular EngineeringKAIST
2020.12.16 View 11074 -
Team USRG’s Winning Streak Continues at the AI Grand Challenge
Team USRG (Unmanned Systems Research Group) led by Professor Hyunchul Shim from the School of Electrical Engineering has won the AI Grand Challenge 2020 held on Nov. 23 at Kintex in Ilsan, Kyonggi-do for the second consecutive year. The team received 7.7 million KRW in research funding from the Ministry of Science and ICT, the organizer of the challenge.
The team took a little over two minutes to complete the rescue operation mission of the challenge. The mission included swerving around seven obstacles, airdropping an aid package, and safely landing after identifying the landing spot. Their drone is the only one that successfully passed through a 10-meter tunnel out of five pre-qualified teams: three from universities and two from companies.
The AI Grand Challenge, which began in 2017, was designed to promote AI technology and its applications for addressing high-risk technical challenges, especially for conducting complex disaster relief operations.
For autonomous flying drones, swerving to avoid objects has always been an essential skill and a big challenge. For their flawless performance in the rescue operation, the team loaded an AI algorithm and upgraded their drone by improving the LiDAR-based localization system and a stronger propulsion system to carry more sensors. The drone weighs 2.4 kg and carries a small yet powerful computer with a GPU.
This AI-powered drone can complete rescue missions more efficiently in complicated and disastrous environments by precisely comprehending where the drone should go without needing GPS. The team also designed an all-in-one prop guard and installed a gripper onto the bottom of the drone to hold the aid package securely.
“We tried hard to improve our localization system better to resolve issues we had in the previous event,” said Professor Shim. Two PhD candidates, Han-Sob Lee and Bo-Sung Kim played a critical role in developing this drone.
After their two-year winning streak, their prize money now totals 2.4 billion KRW, equivalent to the winning prize of the DARPA Challenge. As the winning team, they will collaborate with other champions at the AI track challenge to develop rescue mission technology for a more complex environment.
“The importance of AI technology is continuing to grow and the government is providing large amounts of funding for research in this field. We would like to develop very competitive technology that will work in the real world,” Professor Shim added.
His group is investigating a wide array of AI technologies applicable to unmanned vehicles including indoor flying drones, self-driving cars, delivery robots, and a tram that circles the campus.
2020.12.01 View 7438 -
Three Professors Named to Highly Cited Researchers 2020 List
Distinguished Professor Sukbok Chang from the Department of Chemistry, Distinguished Professor Sang-Yup Lee from the Department of Chemical & Biomolecular Engineering, and Professor Jiyong Eom from the College of Business were named to Clarivate’s Highly Cited Researchers 2020 list.
Clarivate announced the researchers who rank in the top 1% of citations by field and publication year in the Web of Science citation index. A total of 6,167 researchers from more than 60 countries were listed this year and 37 Korean scholars made the list.
The methodology that determines the “Who’s Who” of influential researchers draws on data and analyses performed by bibliometric experts and data scientists at the Institute for Scientific Information at Clarivate. It also uses the tallies to identify the countries and research institutions where these scientific elite are based. More than 6,000 researchers from 21 fields in the sciences, social sciences, and cross field categories were selected based on the number of highly cited papers they produced over an 11-year period from January 2009 to December 2019.
Professor Chang made the list six years in a row, while Professor Lee made it for four consecutive years, and Professor Eom for the last two years. Professor Chang’s group (http://sbchang.kaist.ac.kr) investigates catalytic hydrocarbon functionalization. Professor Lee (http://mbel.kaist.ac.kr) is a pioneering scholar in the field of metabolic engineering, systems, and synthetic biology. Professor Eom’s (https://kaistceps.quv.kr) research extends to energy and environmental economics and management, energy big data, and green information systems.
2020.11.30 View 7770 -
‘WalkON Suit 4’ Releases Paraplegics from Wheelchairs
- KAIST Athletes in ‘WalkON Suit 4’ Dominated the Cybathlon 2020 Global Edition. -
Paraplegic athletes Byeong-Uk Kim and Joohyun Lee from KAIST’s Team Angel Robotics won a gold and a bronze medal respectively at the Cybathlon 2020 Global Edition last week. ‘WalkON Suit 4,’ a wearable robot developed by the Professor Kyoungchul Kong’s team from the Department of Mechanical Engineering topped the standings at the event with double medal success.
Kim, the former bronze medallist, clinched his gold medal by finishing all six tasks in 3 minutes and 47 seconds, whereas Lee came in third with a time of 5 minutes and 51 seconds. TWIICE, a Swiss team, lagged 53 seconds behind Kim’s winning time to be the runner-up.
Cybathlon is a global championship, organized by ETH Zurich, which brings together people with physical disabilities to compete using state-of-the-art assistive technologies to perform everyday tasks. The first championship was held in 2016 in Zurich, Switzerland.
Due to the COVID-19 pandemic, the second championship was postponed twice and held in a new format in a decentralized setting. A total of 51 teams from 20 countries across the world performed the events in their home bases in different time zones instead of traveling to Zurich. Under the supervision of a referee and timekeeper, all races were filmed and then reviewed by judges.
KAIST’s Team Angel Robotics participated in the Powered Exoskeleton Race category, where nine pilots representing five nations including Korea, Switzerland, the US, Russia, and France competed against each other.
The team installed their own arena and raced at the KAIST Main Campus in Daejeon according to the framework, tasks, and rules defined by the competition committee. The two paraplegic pilots were each equipped with exoskeletal devices, the WalkON Suit 4, and undertook six tasks related to daily activities.
The WalkON Suit 4 recorded the fastest walking speed for a complete paraplegic ever reported. For a continuous walk, it achieved a maximum speed of 40 meters per minute. This is comparable to the average walking pace of a non-disabled person, which is around two to four kilometers per hour.
The research team raised the functionality of the robot by adding technology that can observe the user’s level of anxiety and external factors like the state of the walking surface, so it can control itself intelligently. The assistive functions a robot should provide vary greatly with the environment, and the WalkON Suit 4 made it possible to analyze the pace of the user within 30 steps and provide a personally optimized walking pattern, enabling a high walking speed.
The six tasks that Kim and Lee had to complete were:1) sitting and standing back up, 2) navigating around obstacles while avoiding collisions, 3) stepping over obstacles on the ground, 4) going up and down stairs, 5) walking across a tilted path, and 6) climbing a steep slope, opening and closing a door, and descending a steep slope.
Points were given based on the accuracy of each completed task, and the final scores were calculated by adding all of the points that were gained in each attempt, which lasted 10 minutes. Each pilot was given three opportunities and used his/her highest score. Should pilots have the same final score, the pilot who completed the race in the shortest amount of time would win.
Kim said in his victory speech that he was so thrilled to see all his and fellow researchers’ years of hard work paying off. “This will be a good opportunity to show how outstanding Korean wearable robot technologies are,” he added.
Lee, who participated in the competition for the first time, said, “By showing that I can overcome my physical disabilities with robot technology, I’d like to send out a message of hope to everyone who is tired because of COVID-19”.
Professor Kong’s team collaborated in technology development and pilot training with their colleagues from Angel Robotics Co., Ltd., Severance Rehabilitation Hospital, Yeungnam University, Stalks, and the Institute of Rehabilitation Technology.
Footage from the competition is available at the Cybathlon’s official website.
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2020.11.20 View 7636 -
In Memory of Professor Dong-Soo Kim
Pioneering geotechnical engineer Dong-Soo Kim dies at 59
The Department of Civil and Environmental Engineering lost a pioneering scholar in geotechnical engineering, Professor Dong-Soo Kim. Professor Kim died on November 3, after a one-and-a-half-year battle with a brain tumor. He was 59.
Known for his piercing insight and infectious enthusiasm for the deepest questions in geotechnical science and engineering, Professor Kim built an extraordinary academic career while working at KAIST for 26 years. Professor Kim paved the way for establishing the geo-centrifuge experiment facilities at KAIST as part of the KOCED (Korea Construction Engineering Development Collaboratory Management Institute) Projects funded by the Ministry of Land, Infrastructure and Transport. He also served as director of the KOCED Geo-Centrifuge Center.
“He made significant contributions to the growth of the department since his joining and he was at the forefront of the globalization of the department. He passed away so early leaving behind so many projects,” lamented Professor Emeritus Chung-Bang Yun.
“Professor Kim insisted on lecturing despite his serious illness. He wanted to play his part so gracefully for his students until his last days,” said Professor Hyo-Gyong Kwak, the head of the department who was also a close colleague of 25 years. “His captivating warm smile and unwavering mentorship and guidance will be missed by students and faculty alike. We lost an exemplary leader, mentor, colleague, and friend.” One of his colleagues, Professor Gye-Chun Cho said, “We have lost a great professor and colleague in civil engineering worldwide. His impact and legacy will be remembered forever.”
Joining the KAIST faculty in 1994, he began his academic career at the Polytechnique University, New York for three years after earning his PhD at the University of Texas at Austin in 1991. He finished his BS and MS at Seoul National University in 1983 and 1985 respectively.
While at KAIST, he led the Soil Dynamics Lab in 1994 and researched on site characterization via field and lab tests. He also conducted geotechnical centrifuge tests on earthquake and offshore geotechnical problems. His research team studied the seismic design of geotechnical structures and explored the non-destructive testing and evaluation of civil structures.
Professor Kim made profound contributions to understanding fundamental geotechnical engineering problems. More recently, his lab investigated physical modeling using the geo-centrifuge testing machine that could simulate field geotechnical problems on small-scale models. Professor Kim’s perseverance, deep curiosity, and enthusiasm for discovery served him well in his roles as a teacher, mentor, and colleague in the department and beyond. “I thought of him as an elder brother who fully understand everything with generous mind,” said Professor Haeng-Ki Lee, former head of the department.
“I will never forget the hiking trip to Halla Mountain in Jeju last summer. He continuously cheered on the junior professors. Without him, we could not have made it to the summit. His support and encouragement always led us to produce good results and achievement in the labs,” remembered Professor Youngchul Kim. Taking great delight in helping young scientists, he inspired colleagues and students to find their own eureka moments. To professors like Jong-In Han and Ayoung Kim, he was the role model they hope to be due to his rigorous scholarship and generous character. Upon his passing, Professor Jaewook Myung reviewed all the emails he and Professor Kim has sent starting from his undergraduate days at KAIST. “He was my guiding light. He always listened attentively to my struggles from my undergraduate days and advised me very warmly.”
Professor Kim was also known for his key role in the Korean Geotechnical Society. His unmatched leadership led him to serve as the Chair of the Organizing Committee for the 19th International Conference on Soil Mechanics and Geotechnical Engineering in Seoul in 2017. He was the General Secretary of the 5th International Symposium on Deformation Characteristics of Geomaterials. He also served as a chair of the ISSSMGE TC 104 committee.
Professor Kim successfully carried out numerous projects with his research team and supervised more than 60 graduate students. For current students under his supervision, it is still tough to acknowledge the loss of their professor.
Master candidate Yeonjun Kim feels lost moving forward. PhD candidate Junsik Bae said that it is like a bad dream and he feels Professor Kim will still be in his lab whenever he goes inside. One of the staff members who worked with him, Byeol-Nim Cha, remembered that Professor Kim always entered the office with a big smile. “He always asked me how I am doing,” Cha added.
Professor Kim’s trailblazing research was recognized with several awards and honors. Cited as a Top 100 Scientist by the International Biographical Center (IBC) in 2008, Professor Kim received the Young Presidential Research Award from the Korean Academy of Science and Technology in 2002, the Korean Presidential Award on Civil Engineer’s Day in 2011, and the Telford Premium Rewards in 2018. Throughout his career, he authored or co-authored 321 papers in international journals and conference proceedings, and 278 papers in domestic journals and conferences.
President of the Korean Geotechnical Society Choong-gi Chung also eulogized him, “Above his impressive professional contributions, Professor Kim will be remembered forever for his generosity, simplicity, playfulness, and his smile.”
Professor Kim is survived by his wife, son, and daughter.
2020.11.19 View 6584 -
Chairman Soo-Young Lee Named Among the Heroes of Philanthropy in Asia
Chairman Soo-Young Lee from the KAIST Development Foundation was named one of 15 philanthropists who made the biggest donations in the Asia-Pacific region by Forbes Asia on November 11.
The annual Heroes of Philanthropy list features the 15 the most generous individual philanthropists who are donating from their personal fortunes, not through companies. This year, the biggest philanthropies donated to make a difference in wide arrays of sectors such as Covid-19 relief to education and the arts.
Chairman Lee donated totaling 68 billion KRW to KAIST in July. Her donation marked the largest donation KAIST has ever received. She is one of two Korean philanthropists that Forbes selected. Honorary Chairman of GS Caltex Dong-Soo Huh also made the list.
Her donation will establish the Soo-Young Lee Science Education Foundation to support ‘the Singularity Professor program’ that KAIST is launching. She expressed confidence that her donation will fund KAIST researchers to make breakthroughs that will lead to a Nobel Prize.
“Without the advancement of science and technology, Korea cannot be one of the top countries in the world. I believe KAIST can make it with our all supports,” she frequently said when asked why she selected KAIST for her donation.
Chairman Lee previously made generous donations in 2012 and 2016 and said she plans to make another gift to KAIST in the very near future.
2020.11.13 View 5468 -
Drawing the Line to Answer Art’s Big Questions
- KAIST scientists show how statistical physics can reveal art trends across time and culture. -
Algorithms have shown that the compositional structure of Western landscape paintings changed “suspiciously” smoothly between 1500 and 2000 AD, potentially indicating a selection bias by art curators or in art historical literature, physicists from the Korea Advanced Institute of Science and Technology (KAIST) and colleagues report in the Proceedings of the National Academy of Sciences (PNAS).
KAIST statistical physicist Hawoong Jeong worked with statisticians, digital analysts and art historians in Korea, Estonia and the US to clarify whether computer algorithms could help resolve long-standing questions about design principles used in landscape paintings, such as the placement of the horizon and other primary features.
“A foundational question among art historians is whether artwork contains organizing principles that transcend culture and time and, if yes, how these principles evolved over time,” explains Jeong. “We developed an information-theoretic approach that can capture compositional proportion in landscape paintings and found that the preferred compositional proportion systematically evolved over time.”
Digital versions of almost 15,000 canonical landscape paintings from the Western renaissance in the 1500s to the more recent contemporary art period were run through a computer algorithm. The algorithm progressively divides artwork into horizontal and vertical lines depending on the amount of information in each subsequent partition. It allows scientists to evaluate how artists and various art styles compose landscape artwork, in terms of placement of a piece’s most important components, in addition to how high or low the landscape’s horizon is placed.
The scientists started by analysing the first two partitioning lines identified by the algorithm in the paintings and found they could be categorized into four groups: an initial horizontal line followed by a second horizontal line (H-H); an initial horizontal line followed by a second vertical line (H-V); a vertical followed by horizontal line (V-H); or a vertical followed by a vertical line (V-V) (see image 1 and 2). They then looked at the categorizations over time.
They found that before the mid-nineteenth century, H-V was the dominant composition type, followed by H-H, V-H, and V-V. The mid-nineteenth century then brought change, with the H-V composition style decreasing in popularity with a rise in the H-H composition style. The other two styles remained relatively stable.
The scientists also looked at how the horizon line, which separates sky from land, changed over time. In the 16th century, the dominant horizon line of the painting was above the middle of the canvas, but it gradually descended to the lower middle of the canvas by the 17th century, where it remained until the mid-nineteenth century. After that, the horizon line began gradually rising again.
Interestingly, the algorithm showed that these findings were similar across cultures and artistic periods, even through periods dominated by a diversity in art styles. This similarity may well be a function, then, of a bias in the dataset.
“In recent decades, art historians have prioritized the argument that there is great diversity in the evolution of artistic expression rather than offering a relatively smoother consensus story in Western art,” Jeong says. “This study serves as a reminder that the available large-scale datasets might be perpetuating severe biases.”
The scientists next aim to broaden their analyses to include more diverse artwork, as this particular dataset was ultimately Western and male biased. Future analyses should also consider diagonal compositions in paintings, they say.
This work was supported by the National Research Foundation (NRF) of Korea.
Publication:
Lee, B, et al. (2020) Dissecting landscape art history with information theory. Proceedings of the National Academy of Sciences (PNAS), Vol. 117, No. 43, 26580-26590. Available online at https://doi.org/10.1073/pnas.2011927117
Profile:
Hawoong Jeong, Ph.D.
Professor
hjeong@kaist.ac.kr
https://www.kaist.ac.kr
Department of Physics
Korea Advanced Institute of Science and Technology (KAIST)
Daejeon, Republic of Korea
(END)
2020.11.13 View 9526