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Blue-enriched White Light to Wake You Up in the Morning
(from left: Professor Hyun Jung Chung, Professor Hyeon-Jeong Suk, Taesu Kim and Professor Kyungah Choi)
Here is a good news for those of who have difficulty with morning alertness. A KAIST research team proposed that a blue-enriched LED light can effectively help people overcome morning drowsiness. This study will provide the basis for major changes in future lighting strategies and thereby help create better indoor environments.
Considerable research has been devoted to unmasking circadian rhythms. The 2017 Nobel Prize in Physiology or Medicine went to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for unveiling the molecular mechanisms that control circadian rhythms. In particular, the relationship between light and its physiological effects has been investigated since the discovery of a novel, third type of photoreceptor in the human retina in the early 2000s. Rods and cones regulate visual effects, while the third type, photosensitive retinal ganglion cells, regulate a large variety of biological and behavioral processes including melatonin and cortisol secretion, alertness, and functional magnetic resonance imaging (fMRI).
Initial studies on light sources have shown that blue monochromatic, fully saturated lights are effective for stimulating physiological responses, but the relative effectiveness of commercially available white light sources is less well understood. Moreover, the research was more focused on the negative effects of blue light; for instance, when people are exposed to blue light at night, they have trouble achieving deep sleep because the light restrains melatonin secretion.
However, Professor Hyeon-Jeong Suk and Professor Kyungah Choi from the Department of Industrial Design and their team argue that the effects of blue-enriched morning light on physiological responses are time dependent, and that it has positive effects on melatonin levels and the subjective perception of alertness, mood, and visual comfort compared with warm white light.
The team conducted an experiment with 15 university students. They investigated whether an hour of morning light exposure with different chromaticity would affect their physiological and subjective responses differently. The decline of melatonin levels was significantly greater after the exposure to blue-enriched white light in comparison with warm white light.
Professor Suk said, “Light takes a huge part of our lives since we spend most of our time indoors. Light is one of the most powerful tools to affect changes in how we perceive and experience the environment around us.”
Professor Choi added, “When we investigate all of the psychological and physiological effects of light, we see there is much more to light than just efficient quantities. I believe that human-centric lighting strategies could be applied to a variety of environments, including residential areas, learning environments, and working spaces to improve our everyday lives.”
This research was collaborated with Professor Hyun Jung Chung from the Graduate School of Nanoscience and Technology and was published in Scientific Reports (10.1038/s41598-018-36791-5) on January 23, 2019.
Figure 1. Changes in melatonin secretion during day and night time
2019.03.06 View 10540 -
KAIST Develops Analog Memristive Synapses for Neuromorphic Chips
(Professor Sung-Yool Choi from the School of Electrical Engineering)
A KAIST research team developed a technology that makes a transition of the operation mode of flexible memristors to synaptic analog switching by reducing the size of the formed filament. Through this technology, memristors can extend their role to memristive synapses for neuromorphic chips, which will lead to developing soft neuromorphic intelligent systems.
Brain-inspired neuromorphic chips have been gaining a great deal of attention for reducing the power consumption and integrating data processing, compared to conventional semiconductor chips. Similarly, memristors are known to be the most suitable candidate for making a crossbar array which is the most efficient architecture for realizing hardware-based artificial neural network (ANN) inside a neuromorphic chip.
A hardware-based ANN consists of a neuron circuit and synapse elements, the connecting pieces. In the neuromorphic system, the synaptic weight, which represents the connection strength between neurons, should be stored and updated as the type of analog data at each synapse.
However, most memristors have digital characteristics suitable for nonvolatile memory. These characteristics put a limitation on the analog operation of the memristors, which makes it difficult to apply them to synaptic devices.
Professor Sung-Yool Choi from the School of Electrical Engineering and his team fabricated a flexible polymer memristor on a plastic substrate, and found that changing the size of the conductive metal filaments formed inside the device on the scale of metal atoms can make a transition of the memristor behavior from digital to analog.
Using this phenomenon, the team developed flexible memristor-based electronic synapses, which can continuously and linearly update synaptic weight, and operate under mechanical deformations such as bending.
The team confirmed that the ANN based on these memristor synapses can effectively classify person’s facial images even when they were damaged. This research demonstrated the possibility of a neuromorphic chip that can efficiently recognize faces, numbers, and objects.
Professor Choi said, “We found the principles underlying the transition from digital to analog operation of the memristors. I believe that this research paves the way for applying various memristors to either digital memory or electronic synapses, and will accelerate the development of a high-performing neuromorphic chip.”
In a joint research project with Professor Sung Gap Im (KAIST) and Professor V. P. Dravid (Northwestern University), this study was led by Dr. Byung Chul Jang (Samsung Electronics), Dr. Sungkyu Kim (Northwestern University) and Dr. Sang Yoon Yang (KAIST), and was published online in Nano Letters (10.1021/acs.nanolett.8b04023) on January 4, 2019.
Figure 1. a) Schematic illustration of a flexible pV3D3 memristor-based electronic synapse array. b) Cross-sectional TEM image of the flexible pV3D3 memristor
2019.02.28 View 7856 -
KAIST 2019 Commencement at a Glance
(KAIST 2019 Commencement Ceremony)
This year, KAIST awarded a total of 2,705 degrees: 654 PhD degrees, 1,255 master’s degrees, and 796 bachelor’s degrees. Including this year’s numbers, KAIST has conferred a total of 63,830 degrees since its foundation in 1971.
Parents, family, and friends came to campus to congratulate the graduates with big smiles and hugs. Faculty and staff members also attended the ceremony to celebrate their graduation. This year, distinguished guests including National Assembly Member Kyung-Jin Kim and Vice Minister for Science, Technology and Innovation Dae-sik came to celebrate the day with the KAIST community.
During the commencement, KAIST also announced the recipients of its undergraduate academic awards. The Minister of Science and ICT Award was won by Do-Yoon Kim from the Department of Aerospace Engineering, the KAIST Board of Trustee Chairperson Award went to Se-rin Lee from the Department of Materials Science and Engineering, the KAIST Presidential Award was won by Hee-Ju Kim from the Department of Physics, the KAIST Alumni Association President Award went to Hyeon-Seong Park from the School of Electrical Engineering, and finally the KAIST Development Foundation Chairperson Award was won by Gyeong-Hoon Lee from the Department of Mathematical Sciences.
This year’s valedictorian Eun-Seok Jeong from the School of Computing said, “I believe that we are able to stand here today because we challenged ourselves to confront our shortcomings and our uncertainty. If we continue to develop, we will become a better person than we were yesterday.”
(KAIST President Sung-Chul Shin and Woo-Seok Jeong, '19 PhD in Aerospace Engineering)
As a KAIST alumnus and fellow scientist, President Sung-Chul Shin offered his congratulations and emphasized that graduates should continue to pursue the C³ spirit. “In this age of great transformation, embrace challenges and exercise creativity as you have learnt through your education and research at KAIST. And keep in mind the importance of caring for others. Please remember that challenge and creativity will have more meaning if rendered with a caring spirit,” he said.
2019.02.15 View 8596 -
The First Award for Concept Cars, Future Mobility of the Year
KAIST will host an award to recognize the most visionary and inspiring concept cars of the year.
The ‘Future Mobility of the Year (FMOTY)’ Awards recognize concept cars that have made outstanding contributions to future mobility. The first awards ceremony will take place in Korea in March 2019.
The awards will be given to concept cars that exhibit innovative services and practical transportation technology in three categories: private mobility, public and commercial mobility, and personal mobility.
To ensure a fair judging process, the contest invited influential and eminent journalists in the automotive field. They will evaluate the social values and innovative contributions of the concept cars that will pave the way for next-generation transportation.
Concept cars have been neglected in existing automobile awards, such as the ‘Car of the Year’ because they have been considered experimental prototypes only built for showcasing a new vision for the quite far future.
The FMOTY Awards will brings concept cars back into the spotlight and showcase the best ideas and social values of mind-blowing concept cars.
Among 45 concept cars, fifteen candidates were selected as finalists after the initial screening that took place over the last three months: including models from Audi, BMW, Mercedes-Benz, Peugeot, Porsche, Renault, Toyota, Volkswagen, and Volvo. The winners will be announced and awarded in Seoul on March 28th.
Kyung-soo Kim, Dean of the Cho Chun Shik Graduate School of Green Transportation which organizes the award said, “As the automobile industry undergoes an era of transformation, it is crucial to recognize the efforts of automobile companies who are making attempts to create novel forms of mobility. That is why we launched the FMOTY Awards, hoping to add a future-oriented spirit to the existing awards that consider finished vehicles only. By selecting the best concept car, the FMOTY Awards will expand public attention from the present to the future.”
Details can be found on the official website of FMOTY ( www.fmoty.org), where photos of the finalists are also available for download ( http://bitly.kr/JTUUp).
Figure 1. Finalists for the 'Future Mobility of the Year'
2019.02.13 View 6219 -
KAIST Earns AACSB Business School Accreditation
The KAIST College of Business re-earned business school accreditation from the Association to Advance Collegiate Schools of Business (AACSB) International. The school first earned the accreditation in 2003, and has continued to receive the accreditation four consecutive times. Currently only 5% of the 16,000 business schools around the world have earned AACSB accreditation. KAIST received a good evaluation for the competitive research of its faculty, its executive education programs based on strong industry-academia ties, and specialized MBA and master’s program, which includes programs such as social entrepreneurship and green business and policy.Alexander Triantis, dean of the Robert H. Smith School of Business at the University of Maryland and a judge for AACSB Accreditation said, “I was impressed to see students from KAIST have a high standard of knowledge. A number of its graduates continue to be appointed as professors of top universities abroad, which shows its strong global competence”. AACSB was founded in 1916 by deans of business colleges from prestigious universities such as Harvard University, Stanford University and Columbia University, to provide business and accounting accreditation to universities. Evaluation for AACSB accreditation takes place every five years. Schools are evaluated based on fifteen standards, including student admission and graduation requirements, student-faculty ratios, faculty’s intellectual contributions, research infrastructure, global cooperation, and industry-academia programs. They can be eligible for re-accreditation if they satisfy the conditions offered by AACSB International and are committed to continuous improvement every five years. KAIST also earned the accreditation from the European Foundation for Management Development Quality Improvement System (EQUIS) three consecutive times since 2010. In 2013, it earned membership into the Partnership in International Management (PIM). Membership is only possible for those who have AACSB and EQUIS accreditation and they can be listed as a candidate school through voting. The candidate schools can finally earn membership after one year of strict screening. As of January 2019, there are 65 prestigious graduate schools of business, including KAIST, listed as PIM members.
2019.02.01 View 4938 -
Hierarchical Porous Titanium Nitride Synthesized by Multiscale Phase Separation for LSBs
(from left: Professor Jinwoo Lee and PhD candidate Won-Gwang Lim)
A KAIST research team developed ultra-stable, high-rate lithium-sulfur batteries (LSBs) by using hierarchical porous titanium nitride as a sulfur host, and achieved superior cycle stability and high rate performance for LSBs.
The control of large amounts of energy is required for use in an electric vehicle or smart grid system. In this sense, the development of next-generation secondary batteries is in high demand. Theoretically, LSBs have an energy density seven times higher than commercial lithium ion batteries (LIBs). Also, their production cost can be reduced dramatically since sulfur can be obtained at a low price.
Despite these positive aspects, there have been several issues impeding the commercialization of LSBs, such as the low electric conductivity of sulfur, the dissolution of active materials during operation, and sluggish conversion reactions. These issues decrease the cycle stability and rate capability of batteries.
To tackle those issues, Professor Jinwoo Lee from the Department of Chemical and Biomolecular Engineering and his team synthesized a well-developed hierarchical macro/mesoporous titanium nitride as a host material for sulfur. The titanium nitride has a high chemical affinity for sulfur and high electrical conductivity. As a result, it prevents the dissolution of active materials and facilitates the charge transfer. Moreover, the synergistic effect of macropore and mesopore structures allows the stable accommodation of large amounts of sulfur and facilitates the electrolyte penetration.
Previously reported polar inorganic materials have a high affinity for sulfur, but it was challenging to control the porous architecture suitable to the sulfur host. This work breaks such limitations by developing a synthetic route to easily control the porous architecture of inorganic materials, which led to obtaining superior cycle stability and high rate capabilities.
Professor Lee said, “Some problems still remain in commercializing LSBs as next-generation batteries. Hence, there should be a continued research on this matter to solve the issues. Through this research, we secured a key technology for ultrastable, high-rate LSBs.”
This research was led by PhD candidate Won-Gwang Lim and collaborated on by Jeong Woo Han from POSTECH. It was chosen as the cover article of Advanced Materials on January 15, 2019.
Figure 1. Schematic illustration for the synthetic route of co-continuous h-TiN
Figure 2. The hierarchical multiscale porous structure is still retained without any collapse after the conversion to h-TiN. The good retention of the porous structure is attributed to the thick pore wall of the h-TiO₂derived from the block copolymer self-assembly
Figure 3. The cover page of Advanced Materials
2019.01.28 View 6284 -
First Korean Member of OceanObs' Organizing Committee
Professor Sung Yong Kim from the Department of Mechanical Engineering became the first Korean to be elected as an organizing committee member of the international conference OceanObs’19’, specializing in the ocean observing field.
Professor Kim has been actively engaged in advisory panels, technical committees, and working groups for the North Pacific Marine Science Organization (PICES). Through numerous activities, he was recognized for his professionalism and academic achievements, which led him to be appointed as a member of the organizing committee.
The organizing committee is comprised of leading scholars and researchers from 20 countries, and Professor Kim will be the first Korean scientist to participate on the committee.
Since 1999, the conference has been held every decade. Global experts specializing in oceanic observation gather to discuss research directions for the next ten years by monitoring physical, biological, and chemical variables in regional, national, and global oceans and applying marine engineering.
This year, approximately 20 institutes including NASA’s Jet Propulsion Laboratory (JPL), the National Science Foundation, the National Oceanic and Atmospheric Administration, and the European Space Agency will support funds as well as high-tech equipment to the conference.
This year’s conference theme is the governance of global ocean observing systems such as underwater gliders, unmanned vehicles, remote sensing, and observatories. The conference will hold discussions on monitoring technology and information systems to ensure human safety as well as to develop and preserve food resources. Additionally, participants will explore ways to expand observational infrastructures and carry out multidisciplinary approaches.
There will also be collaborations with the Global Ocean Observing System (GOOS) and the Partnership for Observation of the Global Oceans (POGO) to organize ocean observing programs and discuss priorities.
Finally, they will set a long-term plan for solving major scientific issues, such as climate change, ocean acidification, energy, and marine pollution.
Professor Kim said, “Based on the outcomes drawn from the conference, I will carry out research on natural disasters and climate change monitoring by using unmanned observing systems. I will also encourage more multidisciplinary research in this field.”
2019.01.25 View 9064 -
New Members of KAST and Y-KAST 2019
(Professor Eui-Cheol Shin from the Graduate School of Medical Science and Engineering)
Professor Eui-Cheol Shin from the Graduate School of Medical Science and Engineering became a new fellow of the Korean Academy of Science and Technology (KAST) along with 25 other scientists in Korea. He is one of the top virus immunologists in Korea and has published a review article in Nature Reviews Immunology.
Meanwhile KAST selected and announced 26 young scientists under the age 43 who have shown great potential and the creativity to carry out next-generation research. The list of Y-KAST (Young Korean Academy of Science and Technology) includes six KAIST professors: Professor Ji Oon Lee from the Department of Mathematical Sciences, Professor Mi Hee Lim from the Department of Chemistry, Professor Shin-Hyun Kim from the Department of Chemical and Biomolecular Engineering, Professor Jung-Ryul Lee from the Department of Aerospace Engineering, Professor Hyunjoo Jenny Lee from the School of Electrical Engineering, and Professor Yeon Sik Jung from the Department of Materials Science and Engineering.
KAST conferred their fellowships and Y-KAST membership during the New Year Reception.
2019.01.22 View 7597 -
Fabrication of Shape-conformable Batteries with 3D-Printing
(from left: Dr. Bok Yeop Ahn, Dr. Chanhoon Kim, Professor Il-Doo Kim and Professor Jennifer A. Lewis)
Flexible, wireless electronic devices are rapidly emerging and have reached the level of commercialization; nevertheless, most of battery shapes are limited to either spherical and/or rectangular structures, which results in inefficient space use. Professor Il-Doo Kim’s team from the Department of Materials Science at KAIST has successfully developed technology to significantly enhance the variability of battery design through collaboration research with Professor Jennifer A. Lewis and her team from the School of Engineering and Applied Sciences at Harvard University.
Most of the battery shapes today are optimized for coin cell and/or pouch cells. Since the battery as an energy storage device occupies most of the space in microelectronic devices with different designs, new technology to freely change the shape of the battery is required.
The KAIST-Harvard research collaboration team has successfully manufactured various kinds of battery shapes, such as ring-type, H, and U shape, using 3D printing technology. And through the research collaboration with Dr. Youngmin Choi at the Korea Research Institute of Chemical Technology (KRICT), 3D-printed batteries were applied to small-scale wearable electronic devices (wearable light sensor rings).
The research group has adopted environmentally friendly aqueous Zn-ion batteries to make customized battery packs. This system, which uses Zn2+ instead of Li+ as charge carriers, is much safer compared with the conventional lithium rechargeable batteries that use highly inflammable organic electrolytes. Moreover, the processing conditions of lithium-ion batteries are very complicated because organic solvents can ignite upon exposure to moisture and oxygen.
As the aqueous Zn-ion batteries adopted by the research team are stable upon contact with atmospheric moisture and oxygen, they can be fabricated in the ambient air condition, and have advantages in packaging since packaged plastic does not dissolve in water even when plastic packaging is applied using a 3D printer.
To fabricate a stable cathode that can be modulated in various forms and allows high charge-discharge, the research team fabricated a carbon fiber current collector using electrospinning process and uniformly coated electrochemically active polyaniline conductive polymer on the surface of carbon fiber for a current collector-active layer integrated cathode. The cathode, based on conductive polyaniline consisting of a 3D structure, exhibits very fast charging speeds (50% of the charge in two minutes) and can be fabricated without the detachment of active cathode materials, so various battery forms with high mechanical stability can be manufactured.
Prof. Kim said, “Zn-ion batteries employing aqueous electrolytes have the advantage of fabrication under ambient conditions, so it is easy to fabricate the customized battery packs using 3D printing.”
“3D-printed batteries can be easily applied for niche applications such as wearable, personalized, miniaturized micro-robots, and implantable medical devices or microelectronic storage devices with unique designs,” added Professor Lewis.
With Dr. Chanhoon Kim in the Department of Materials Science and Engineering at KAIST and Dr. Bok Yeop Ahn School of Engineering and Applied Sciences at Harvard University participating as equally contributing first authors, this work was published in the December issue of ACS Nano.
This work was financially supported by the Global Research Laboratory (NRF-2015K1A1A2029679) and Wearable Platform Materials Technology Center (2016R1A5A1009926).
Figure 1.Fabrication of shape-conformable batteries based on 3D-printing technology and the application of polyaniline carbon nanofiber cathodes and wearable electronic devices
Figure 2.Fabricated shape-conformable batteries based on a 3D-printing method
Meanwhile, Professor Il-Doo Kim was recently appointed as an Associate Editor of ACS Nano, a highly renowned journal in the field of nanoscience.
Professor Kim said, “It is my great honor to be an Associate Editor of the highly renowned journal ACS Nano, which has an impact factor reaching 13.709 with 134,596 citations as of 2017. Through the editorial activities in the fields of energy, I will dedicate myself to improving the prominence of KAIST and expanding the scope of Korea’s science and technology. I will also contribute to carrying out more international collaborations with world-leading research groups.”
(Associate Editor of ACS Nano Professor Il-Doo Kim)
2018.12.20 View 9368 -
Optimal Immuno-Therapeutic Strategies for Liver Cancer
KAIST medical scientists have presented a heterogeneity of immune cell exhaustion in the cancer environment, providing evidence and rationale for designing optimal strategies for immune checkpoint inhibitors in liver cancer patients.
They succeeded in distinguishing the hepatocellular carcinoma group from the exhausted tumor infiltrating immune cell composition of liver cancer patients. The study, conducted in collaboration with Asan Medical Center, confirmed the applicability for liver cancer patients, providing a new path for personalized precision medicine as well as a new model for translational research.
Our immune system is able to destroy cancerous cells in our body, however sometimes cancer cells can adapt and mutate, effectively hiding from our immune system. One of the mechanisms that has evolved to prevent eradication by the immune system is to functionally silence effector T cells, termed T-cell exhaustion, that is mainly mediated by immune checkpoint molecules such as PD-1, TIM-3, and LAG-3.
Recent breakthroughs and encouraging clinical results with various immune checkpoint inhibitors (ICIs), such as anti-PD-1 monoclonal antibodies (mAbs) and anti-CTLA-4 mAbs, have demonstrated tremendous potential to cure cancers through the immune activation of exhausted T cells. Immune checkpoint inhibitors showed significant clinical benefits for several types of cancers, leading to their wide application in clinical practice.
Anti-PD1 blocking antibodies are one of the most representative agents in this class of drug. However, it has been challenging to precisely understand the biological and clinical significance of T-cell exhaustion in cancer. A KAIST research team led by Professor Su-Hyung Park reported the heterogeneity of T-cell exhaustion in hepatocellular carcinoma (HCC) and its potential clinical implications in Gastroenterology on December 4.
The team revealed that heterogeneous T-cell exhaustion status is determined by the differential PD-1 expression levels in CD8+ T cells in liver cancer patients. The authors found that tumor-infiltrating CD8+ T cells with high PD-1 expression from liver cancer patients are functionally impaired and co-express other immune checkpoint receptors such as TIM-3 and/or LAG3, compared to those with low PD-1 expression.
Moreover, based on these results, the authors suggested that liver cancer patients can be classified into two distinct subgroups. Patients having high PD-1 expression levels in the tumor microenvironment showed more aggressive tumor features and biomarkers predicting a favorable response to anti-PD1 therapy. The research team also demonstrated that only liver cancer patients having high PD-1 expression are susceptible to combined immune checkpoint blockade-based therapies.
Prof. Park said, “The new classification of liver cancer patients identified by this study can be utilized as a biomarker to predict the response of current cancer immunotherapy targeting the PD-1 pathway.” He also said they will continue to conduct research on T-cell exhaustion and activation in various types of cancer, which could lead to a better understanding of T-cell response against cancer, thereby providing evidence for future cancer immunotherapy to achieve the ultimate goal to prolong the survival of cancer patients.
2018.12.18 View 4516 -
KAIST Seals the Deal for Kenya KAIST Project
KAIST will participate in Kenya’s strategic economic development plan under the provision of a turnkey-based science and technology education consultancy for the establishment of the Kenya Advanced Institute of Science and Technology (Kenya KAIST).KAIST signed the contract on November 30 with the Konza Technopolis Development Authority to establish Kenya KAIST. Korea Eximbank will offer a 95 million USD loan to the Kenyan government for this project. The project will include the educational and architectural design and construction of Kenya KAIST. The campus will be constructed in the Konza Techno City nearby Nairobi by 2021, with the first batch of 200 graduate students starting classes in 2022. KAIST, in consortium with Samwoo and Sunjin architecture and engineering companies, will take the lead of the three-year project, with the kick-off ceremony planned at the end of next January in Nairobi. The Kenyan government plans to transform Kenya into a middle-income country under Vision 2030 through promoting science, technology, and innovation for national economic growth. Nicknamed Africa’s Silicon Savannah, Konza Techno City is a strategic science and technology hub to realize this vision. To this end, the medium-term plan set a goal to provide specialized research and training in various leading-edge engineering and advanced science fields.In the two-phase evaluation of the consultancy bidding, KAIST won preferred bidder status in the technical proposal evaluation, outbidding three other Korean consortia. Invited to the financial proposal bidding, the KAIST consortium successfully completed month-long contract negotiations with Kenya last week.KAIST will develop academic curricula for six initial departments (Mechanical Engineering, Electrical/Electronic Engineering, ICT Engineering, Chemical Engineering, Civil Engineering, and Agricultural Biotechnology), which will lay the ground work for engineering research and education in Kenya to meet emerging socioeconomic demands. In addition, KAIST will provide the education of basic sciences of math, physics, chemistry, and biology for students.It is also notable that the Kenyan government asked to develop an industry-academy cooperation program in Konza Techno City. It reflects the growing industrial needs of Kenya KAIST, which will be located in the center of the Konza Technopolis. It is anticipated that the technopolis will create 16,675 jobs in the medium term and over 200,000 after completion, positioning Kenya as an ICT hub within the region.KAIST also shares a similar history of establishment with Kenya KAIST, as it will be built with a foreign loan. KAIST, created by the Korean government in 1971 to drive the economic engine through advancement of science and technology with a six-million USD loan from USAID, has now become a donor institution that hands down science and technology education systems including the construction of campuses to underdeveloped countries.The successful case of KAIST has been benchmarked by many countries for years. For instance, KAIST set up the curriculum of the nuclear engineering program at the Khalifa University of Science and Technology in UAE in 2010. In China, Chongqing University of Technology is running its electrical engineering and computer science programs based on the educational systems and curricula offered by KAIST from 2015. In October, KAIST also signed an MOU with the Prince Mohammad Bin Salman College of Cyber Security, AI, and Advanced Technologies in Saudi Arabia to provide the undergraduate program for robotics.Among all these programs benchmarking KAIST, Kenya KAIST clearly stands out, for it is carrying out a turnkey-based project that encompasses every aspect of institution building ranging from educational curriculum development to campus construction and supervision.President Sung-Chul Shin is extremely excited about finalizing the deal, remarking, “It is of great significance that KAIST’s successful development model has carved out a unique path to becoming a global leading university that will benefit other countries. In only a half century, we have transitioned from a receiver to a donor institution, as the country itself has done.”“KAIST will spare no effort for Kenya KAIST to become a successful science and technology university that will play a crucial role in Kenya’s national development. I believe Kenya KAIST will be an exemplary case of an ODA (Official Development Assistance) project based on the development of science and technology to benefit underdeveloped countries,” he added.
2018.12.03 View 8499 -
From Concept to Reality: Changing Color of Light Using a Spatiotemporal Boundary
(from left: Professor Bumki Min, PhD candidate Jaehyeon Son and PhD Kanghee Lee)
A KAIST team developed an optical technique to change the color (frequency) of light using a spatiotemporal boundary. The research focuses on realizing a spatiotemporal boundary with a much higher degree of freedom than the results of previous studies by fabricating a thin metal structure on a semiconductor surface. Such a spatiotemporal boundary is expected to be applicable to an ultra-thin film type optical device capable of changing the color of light.
The optical frequency conversion device plays a key role in precision measurement and communication technology, and the device has been developed mainly based on optical nonlinearity.
If the intensity of light is very strong, the optical medium responds nonlinearly so the nonlinear optical phenomena, such as frequency doubling or frequency mixing, can be observed. Such optical nonlinear phenomena are realized usually by the interaction between a high-intensity laser and a nonlinear medium.
As an alternative method frequency conversion is observed by temporally modifying the optical properties of the medium through which light travels using an external stimulus. Since frequency conversion in this way can be observed even in weak light, such a technique could be particularly useful in communication technology.
However, rapid optical property modification of the medium by an external stimulus and subsequent light frequency conversion techniques have been researched only in the pertubative regime, and it has been difficult to realize these theoretical results in practical applications.
To realize such a conceptual idea, Professor Bumki Min from the Department of Mechanical Engineering and his team collaborated with Professor Wonju Jeon from the Department of Mechanical Engineering and Professor Fabian Rotermund from the Department of Physics. They developed an artificial optical material (metamaterial) by arranging a metal microstructure that mimics an atomic structure and succeeded in creating a spatiotemporal boundary by changing the optical property of the artificial material abruptly.
While previous studies only slightly modified the refractive index of the medium, this study provided a spatiotemporal boundary as a platform for freely designing and changing the spectral properties of the medium. Using this, the research team developed a device that can control the frequency of light to a large degree.
The research team said a spatiotemporal boundary, which was only conceptually considered in previous research and realized in the pertubative regime, was developed as a step that can be realized and applied.
Professor Min said, “The frequency conversion of light becomes designable and predictable, so our research could be applied in many optical applications. This research will present a new direction for time-variant media research projects in the field of optics.”
This research, led by PhD Kanghee Lee and PhD candidate Jaehyeon Son, was published online in Nature Photonics on October 8, 2018.
This work was supported by the National Research Foundation of Korea (NRF) through the government of Korea. The work was also supported by the Center for Advanced Meta-Materials (CAMM) funded by the Korea Government (MSIP) as the Global Frontier Project (NRF-2014M3A6B3063709).
Figure 1. The frequency conversion process of light using a spatiotemporal boundary.
Figure 2. The complex amplitude of light at the converted frequency with the variation of a spatiotemporal boundary.
2018.11.29 View 6940