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2018-08 07

[Academics][Excellent R&D] Developing Revolutionary Energy Harvesters

As it is a global agenda to adopt a lifestyle that is more environmentally friendly, developing technology that allows eco-friendly processes and production outcomes has also shifted into focus. Professor Sung Tae-hyun's (Electrical Engineering) research on energy harvesting technology is a prime example that shines a ray of hope onto our path of sustainable development. According to research from Cambridge University, only 12 percent of electric power generated from a power plant is used, while the other 88 percent goes to waste. Consequently, "energy harvesing," the idea of saving and using the wasted energy, has become a crucial research topic for more effective and efficient use of energy generated. It would eiminate concerns about creating a completely different type of power plant or unintentionally harming the environment. "Energy harvesting technology will allow us to convert various types of wasted energy into usable energy,” said Sung. Sung Tae-hyun (Electrical Engineering) explains the different types of energy and how massive an amount of it is wasted. There are different types of convertible energies such as piezoelectric energy (electric energy created from vibration), heat energy (electric energy created from heat), and photovoltaic energy (electric energy created from lighting). Sung focused on piezoelectric and photovoltaic energy when researching energy harvesting technology. The purpose of his research was to successfully create an "energy harvestor" with a sensor that detects the different types of energy, then converts them accordingly to electric energy that is entirely usable and more environmentally friendly. “Sensor technology is actually the core of the Fourth Industrial Revolution since everything is connected through internet of things (IoT). It can detect anything anywhere without limitations, and that’s what would make the energy conversion process more efficient, especially in places where all types of energy are generated.” Energy harvestors demonstrated in a smart factory (Photo courtesy of Sung) Sung is in charge of Hanyang University's (HYU's) SEED laboratory that researches energy harvesting technology. In 2011, it even broke a record for retaining the world’s best piezoelectric energy harvesting data. According to Sung, he approached the energy waste problem by first communicating with the workers in the field, detecting and redefining the problem at hand, moving on to the ideation process, creating prototypes, and then testing it out to see if it was realistically applicable and effective. Sung is now in the process of testing out the developed energy harvestors in four big industries such as LED production, smart factories (industry where the whole production process is combined with digital automation solutions), and industries where both offices and production scenes are located in the same building and power plants. “Currently, we are working on the development and commercialization of applicable IoT sensors applied to energy harvestors, but we hope to create harvestors with massive energy conversion capacity in the future. Not letting any energy go to waste is the main goal,” said Sung. Sung explains the application process of energy havestors in various industries. Behind Sung’s passionate research, there was a strong drive that was truly inspirational. “Our lab is called the SEED lab, like the seed in an apple. You may know how many seeds are generally in an apple, but you never know how many of them will actually become an apple. It is the work of a miracle, and that is the kind of miracle that our lab members wish to achieve together. I ask myself, what kind of fruit am I expecting in 10 or 20 years when I’m planting this seed? In other words, what is my goal in life that takes the form of the fruit? There are so many people that eat the seed before it grows just to fulfill their self-interest. I’d say that those people are myopic, as they may be full and satisfied for the moment, but they will not be in the future. It sure takes a long time to grow and harvest the seed, but once it grows and starts to bear fruit, a never-ending cycle begins. One seed will bear hundreds of fruits ever year. So the next question is, how will you use these fruits? For me, that’s the question of what I want to achieve in my life, and my life goal is to give back the fruits I’ve harvested to the society, and spread the happiness.” Sung talks about his beliefs and philosophy, ending with some inspirational advice for Hanyang students. “I hope that I can share this belief with the Hanyang community. I hope that we can work together to grow the seeds of Hanyang into a strong tree that will bear many fruits, and spread the miracle to the world. That being said, I would like to tell the students not to be afraid of failure, to have a life-goal that can change the world, not to be devastated from failure, to always be positive but not conceited nor arrogant, and to love challenges. Our body is systematically goal-oriented, and once we have a goal, it becomes our drive to keep going even when we are tired. On top of that, if you think that our purpose in life is for the happiness of our community, then you will become a true global leader.” Park Joo-hyun julia1114@hanyang.ac.kr Photos by Choi Min-ju

2018-07 30

[Academics][Researcher of the Month] Observation of Unique Properties of Anti-PT-Symmetric Systems

Professor Song Seok-ho (Department of Physics) has recently announced his research on the observation of an Anti-Parity-Time (APT)-Symmetric exceptional point and energy-difference conserving dynamics in electric circuit resonators. When dividing an electric circuit in half, the two parts show a symmetric stream in both time and space. This is referred to as Parity-Time (PT) Symmetry, which enables electricity to flow in the same stream in both directions inside an electric circuit. By "breaking" the unidirectional converter, the symmetric stream of the forward and backward propagation differs, and the PT-Symmetric form is broken. This picture shows the breaking of the Parity-Time (PT) - symmetric form and how the flow of light changes. By breaking the symmetric middle part, the forms of foward and backward propagation differ, which allows for the creation of diodes. (Photo courtesy of Song) Breaking the PT-Symmetric form allows for the creation of diodes which are semiconductor devices that allow electricity to flow only in one direction and prevent any form of backward propagation. Being a key element of the flow of electricity within an electric circuit, the creation of photodiodes has been a long-term goal in the field of nanophotonics. Based upon the idea of substituting electricity with light, which would allow electric devices to be used with higher speed and energy efficiency, nanophotonics have long been troubled with a loss of energy due to the absence of diodes which allow the efficient flow of energy. Thus, Song’s current research of creating diodes through the "breaking" of PT Symmetries has significance, as it may provide a foothold for the creation of photodiodes. Song has verified his research by successfully breaking symmetries within electric circuits formed with resistance-electric condensers. The experimental process was made as simple as possible based upon the professor’s belief that easy verification leads to easy commercialization. “It is the process of thinking out ideas that should be given effort, whereas the experimental process should be done with ease,” explained Song. This can be seen in the fact that only simple devices with educational purposes were used in the verification of this research. Professor Song Seok-ho shared his research philosophy of the making process which should receive the bulk of time and effort. On the other hand, he mentioned that the experimental process should be conducted as simply as possible, as simple verification leads to simple commercialization. When asked of his future plans, Song explained how he has managed to break through one mere field of nanophotonics. He also maintained that “there are so many fields to overcome. By applying concepts to each field, breaking through the current limitations of physics is my next goal.” Succeeding with the observation of anti-PT-symmetries, it does not seem like it will be long before Song provides another foothold towards a novel breakthrough in the field of nanophotonics. Choi Seo-yong tjdyd1@hanyang.ac.kr Photos by Choi Min-ju

2018-07 05

[Academics][Excellent R&D] Laying the Stepping Stones for Future Software Technology

From chemistry to physics, scientific fields take great strides every day. This is even more the case for computer science, with the world having embarked on the 4th industrial revolution - a revolution created through an extensive integration of information technology. Technologies such as artificial intelligence, big data, and the Internet of Things (IoT) have already been brought to reality to a certain extent. In light of these advances, the improvements in software technology by Professor Won You-jip (Department of Computer Science and Engineering) have received grand recognitions for tearing down the barriers to continuous development. The interview with Won You-jip (Department of Computer Science and Engineering) was held in his office on July 4th, 2018. A rough explanation of Won's research would be as follows: if we modify a standard computer, expanding its memory capacity by 100 times, and increasing the number of Central Processing Units (CPU) to 100, the seemingly improved computer would not be 100 times faster than before. In fact, it would be even slower than the standard version. The essential problem lies in the software; the algorithm for the new computer would have to be redesigned to manage the expanded resources in the most efficient manner. “It would be like driving a supercar on an unpaved road,” explained Won, providing a metaphor to emphasize the pointlessness of developing hardware without the sufficient software to manage it. However, the reality is that the speed of software development has remained rather stagnant compared to the restless development of hardware technology. On this point, Won’s research has received a passionate welcome by the international community for paving new roads for the future of software technology. Althernative designs for CPU management and Input/Output management as proposed by Won's research (Photo courtesy of Won Youjip) In a nutshell, Won provided key technologies for operating systems to support scalability, that is, the ability to add more CPUs, and for them to quickly make full use of the software. To elaborate, he categorized the roles of operating systems into CPU management, huge memory management, and file input/output management, and developed essential technologies for each domain after an analysis of the latest trends and prospective future of their hardware. Won essentially solidified the possibility of scalability, maximized the used of large-scale memory space, and improved the I/O management to prevent operation delays. Won’s research was greatly facilitated with the help of the Electronics and Telecommunications Research Institute (ETRI), who granted access to their super computer for research and experiments. With their assistance and his dedication, Won has been recognized as the forerunner in his field, having won two Best Paper Awards from conferences held by USENIX, also known as The Advanced Computing Systems Association. Won was awarded two among the three Best Paper Awards ever given to recipients in Korea. No other countries in Asia have ever won the award. USENIX conferences are the most respected and historical in the field, with the programming language JAVA having been introduced in one of their past conferences. Won considered being awardedthe award for best paper at USENIX to be an extreme honor. Once Won introduces the final version of his work, it is expected to allow software to be designed for manycore (computers with many cores) hardware to be built in 50 to 60 years-time. It will support super computers, allowing AI calculations and machine deep learning. Furthermore, it will be applied to servers to maximize the use of their resources, contributing significantly to their efficiency. Won’s findings not only enable future technology, but make it economic and efficient. Won is also a dedicated instructor. When asked of his greatest aspiration, Won answered that his wish is for his students to become the best developers of Silicon Valley. He interacts with his students on a frequent basis, well above the domains of lab work. A piece of advice that he had for his students was to become the best. “Rise above your failures, keep your head up, and become the best in your field,” commented Won. He believes that regardless of the skill or profession, if there is something you want to do, you should "Start digging and get to the bottom of it.” Lee Chang-hyun pizz1125@hanyang.ac.kr Photos by Kang Cho-hyun

2018-06 25 Headline News

[Academics][Researcher of the Month] Finding a Cure Through Direct Intranasal Delivery

Flaviviruses like the West Nile virus (WNV), Japanese encephalitis (JEV), and Zika are neurotropic, causing neurological complications or death to those with low immune systems. There is now a cure in development called the siRNA approach which has demonstrated promising results in treating viral infections in animal models. However, several complications exist when it comes to treating humans. Lee Sang-kyung (Department of Bioengineering), along with his fellow researchers, has come up with a solution in his paper "Small Interfering RNA-Mediated Control of Virus Replication in the CNS is Therapeutic and Enables Natural Immunity to West Nile Virus." Lee Sang-kyung (Department of Bioengineering) explains the direct intranasal delivery process on June 22nd. The small interfering RNA (siRNA) is a therapeutic strategy targeting illnesses such as cancer, inflammation, and genetic disorders. This strategy was proven to be successful in treating various viral infections including encephalitis-induced morbidity and mortality, in animal subjects. However, there have been several complications regarding its application to human brains. One of the challenges was due to human anatomy being quite different from that of animal test subjects like mice. After the long research process, it was clear that direct delivery of siRNA to the brain was the best method of treatment. However, not only was finding the right treatment of viral encephalitis (inflammation of the brain) challenging, but the direct delivery of siRNA effectively across the blood-brain barrier (BBB) was a huge block as well. The blood-brain barrier is a filtering mechanism of the capillaries that carries blood to the brain and spinal cord tissue, blocking the passage of certain substances. This basically means that intruding substances are blocked so nothing goes in, and nothing goes out. This makes it harder for the research to continue. The intranasal delivery device that allows mice to be seated in a natural "Mecca" position. (Photo courtesy of Lee) To overcome this problem, Lee and his fellow researchers came up with the intranasal delivery method that allows a substance's direct delivery to the brain while circumventing the challenges associated with the blood-brain barrier. This method was based on the unique connection in human anatomy between the brain and the outer world through the olfactory nerve. Lee was able to invent an intranasal delivery device for WNV-infected mice at late stages of the neuroinvasive disease in hopes of demonstrating that the treatment would bring results in recovery. The mice seated on the platform were naturally placed into the "Mecca" position, which is the best angle for proper direct drug delivery. The siRNA delivered through this route revealed a remarkable therapeutic effect in reducing brain viral load, neuropathology, and mortality even when the treatment was initiated at late stages of WNV infection. Furthermore, the treatment allowed the natural protective immune responses to be triggered outside of the brain that would result in prevention after recovery. This discovery will allow active studies to be conducted in brain research and therapy in the future. Lee explaining the difference in human and animal nasal cavities in his lab, June 22nd. However, there are still more challenges to overcome. Animal subjects used in the experiments such as mice, have the anatomical difference of having a nasal cavity that is six times larger than that of a human being's. This means that the amount of the substance that can be absorbed through a human nasal epithelium (a type of animal tissue) is reduced. The "Mecca" position is a crucial discovery in the steps to overcoming such challenge, but further research is needed. Lee hopes that through the use of the intranasal drug delivery device, they will be able to discover the optimized method of delivery which will be suitable to human anatomy, thus preventing thousands from suffering and death. Lee's research and discovery can be read in detail in the Cell Host & Microbe scientific journal as well as on Signet Biotech's website (signetbiotech.com). Park Joo-hyun julia1114@hanyang.ac.kr Photos by Lee Jin-myung

2018-06 18

[Academics][Excellent R&D] Organic-Inorganic Hybrid Multi Layers

Barrier films that have the ability to block moisture and aerial gas have long been a concern of the packaging industry, especially in the display business. The penetration of such substances leads to a degradation of display materials to protect, which is the main reason why barrier films are utilized. Song Tae-seob (Department of Energy Engineering) has provided a solution to this troublesome dilemma, by proposing the use of using organic-inorganic hybrid multi layers. The use of inorganic materials when making a barrier film is highly effective in blocking the penetration of other substances, but the heat treatment and the use of the equipment comes with a high price tag. On the other hand, organic materials have an easier production process, yet are relatively more vulnerable to penetration by moisture and air. Thus, Song has converged these two materials, which would result in a barrier film higher in both ability and cost efficiency. Song Tae-seob (Department of Energy Engineering) explained how converging organic and inorganic materials can result in the production of a barrier with higher abilities and improved cost efficiency. According to Song, there have been techniques to combine the two materials, but they have not yet been applied to the production of barrier films. Thus, the remaining task for Song was to focus upon making a convergence of the two materials and managing to evenly spread and disperse the inorganic material within the organic solution. "Inorganic materials have a tendency to crumple down within an organic solution. Therefore, finding a way to alleviate this mass and allow them to spread evenly within the solution is a key factor to our research," explained Song. Being a professor in the Department of Energy Engineering and primarily studying batteries, Song has had hardships in this relatively unfamiliar field of research. As it is applying an already existing technique, Song and his laboratory members have focused on developing their technologies while avoiding existing patents. Having the need to develop a product from a new perspective with a novel concept, while diverting from current technologies, Song had another barrier to overcome. However, once such hardships are overcome and the current research is fully conducted, the outcomes will be significant. By localizing the novel barrier film technique, the domestic industry will prosper economically. “The domestic display business will benefit from being supplied with products that are more efficient in both cost and capacity. Furthermore, the barriers can also be extended to various businesses such as solar cells, which have also been troubled with moisture and air penetration," commented Song. Song and his students showing their strong will to develop an organic-inorganic hybrid material barrier. From the left, Lee Kang-chun (Energy Engineering, PhD Degree), Song, Jo Seong-han, Kim Gae-un, and Park Sang-woo (Energy Engineering, Master's program). Choi Seo-yong tjdyd1@daum.net Photos by Choi Min-ju

2018-05 28

[Academics][Researcher of the Month] Efficient and Aesthetic Hybrid Solar Cells

Professor Ko Min-jae recently made the cover article of Advanced Energy Materials with “Room-Temperature Vapor Deposition of Cobalt Nitride Nanofilms for Mesoscopic and Perovskite Solar Cells.” The research Ko has been conducting since 2008 deals with the hybrid solar cell, which is more flexible, lighter and more versatile than conventional silicon solar panels. The article focuses on Ko and his research team's development of a power conversion efficient nanofilm made of cobalt nitride (CoN). As it can be dye-sensitized and bent freely, Ko proposes that this material can be applied on flexible and wearable devices in the future, at an affordable cost. “If we use CoN nanofilms, electricity can be generated from everyday devices and objects, not only from thermoelectric or nuclear power plants. By utilizing natural renewable energy, the human race can develop sustainably, and that is very important,” Ko mentioned in the interview. The new finding can also generate power from weak lights such as the sun on a cloudy day or even from indoor fluorescent lights. The reason behind the reduced cost is the simple production process. Conventional silicon solar panels require special devices to assemble, which are big and expensive. Finding the right combination of substances that induce stable synergy is the hardest part and the reason Ko’s lab is one of the leaders in the solar power field. Ko mentioned, “Idea is the key, and it is wonderful that I can see if the idea works or not in two days.” It is predicted that the CoN nanofilm will be commercialized in five years. "Fighting!" Ko and his students are posing and assuring their will to work hard. From the left, Yoo Yong-suk (Chemical Engineering, Master's program), Ko Min-jae and Kim Dong-hwan (Chemical Engineering, 4th year). Kim So-yun dash070@hanyang.ac.kr Photos by Kang Cho-hyun

2018-05 21

[Academics]The Effects of Representation Tool (Visible-Annotation) Types to Support Knowledge Building in Computer-Supported Collaborative Learning

South Korea has the reputation of having a competitive educational environment for students. Korean students are constantly either in school or in private educational institutions, spending about 15 hours a week just studying. However, the Korean educational model is always described as a very stressful, authoritarian, brutally competitive, and unidirectional educational method. The unidirectional, teacher-centered model has always been criticized as it hinders students from formulating their own thoughts. That is why Kim Dong-sik, professor of the Department of Educational Technology, and his two students Shin Yoon-hee and Jung Jae-won, collaborated in writing the paper, “The Effects of Representation Tool (Visible-Annotation) Types to Support Knowledge Building in Computer-Supported Collaborative Learning.” Process of collaborative knowledge construction (Photo courtesy of Kim) The adoption of technology as a learning mechanism has led to the wide use of online platforms such as knowledge forums and concept maps. Such online education platforms help to maximize the efficiency of learning and the cultivation of high-quality information through active discussions. Kim, Shin, and Jung emphasize that communication activities that include sharing professional knowledge and different perspectives can enhance the level of learning performance. However, being in a computer-supported collaborative learning (CSCL) environment in the absence of appropriate discussion tools can lead to ineffective learning processes and unsuccessful learning performance, due to a lack of accuracy during the knowledge-sharing stage and failure of fostering higher-quality knowledge construction for online discussion. Kim explains the importance of collaborative learning in his office on May 16th. To overcome the limitations, Kim, Shin, and Jung came up with a new tool of visible annotations, adopting the linking annotation method. This method basically links a participant’s contributions with the entire related text provided by the other participants or the instructor. It plays a significant role in forming a shared frame of reference from which to draw higher-level solutions through meaningful conversations. Kim, Shin, and Jung’s visible annotations can be seen as a developed version of the shared frame of reference which attempts to overcoming limitations of linked annotations, as it had no influence on promoting interactions aimed at clarification and interpretation. “Collaboration is crucial. There is collaboration everywhere in our society. We collaborate wherever we are, except at school. Education is unidirectional, and we want to change that,” said Kim. Structure of visible annotations (TLL type) (Photo courtesy of Kim) To investigate which representative tool type would enhance the accuracy of shared knowledge and foster a high level of constructed knowledge in the CSCL environment, Kim, Shin, and Jung came up with three types of visible annotations to test out on college students. They are TL type (content-understanding learning phase and content-understanding), TLL type (concept-understanding for key concepts, content-understanding, then problem-solving learning phase for completing the lesson) and C type (controlled content-understanding learning phase). The concept-understanding type of learning phase focuses on defining the meaning and explaining the pros and cons of key terms; the content-understanding learning phase focuses on asking, explaining, and commenting on the sentence-based learning content; and the problem-solving learning phase focuses on negotiating various opinions and deriving solutions for completing the lesson task. Shin is a very talented student, soon to receive her doctorate in educational technology. After weeks of experimenting, Kim, Shin, and Jung were able to conclude that the TLL type of visible annotation was the most effective in enhancing the accuracy of shared knowledge. “The conventional representation tool has limitations, as it cannot help shared knowledge reach a higher-quality cognitive domain as processes leading to problem awareness, opinion sharing, and collaborative troubleshooting have not been fully considered,” said Shin. Kim added, “TLL specifically divides the stage for the users to first understand the concept key words, then move on to the next step of understanding specific content, and then lastly create active discussions to help individuals consolidate their opinions based on accurate shared knowledge. That’s the true meaning of collaborative education." Park Joo-hyun julia1114@hanyang.ac.kr Photos by Kang Cho-hyun

2018-05 14

[Academics][Excellent R&D] Heading for the World of New Physics

The field of physics is largely divided into three categories: particle, optics, and condensed matter physics. Especially in the field of particle physics, the Standard Model is a theory that explains almost every phenomenon in the universe. However, how would you feel if something that you’ve been trusting for the last 50 years turned out to be wrong? Professor Cheon Byung-gu (Department of Physics), is trying to solve this question through his new research project titled "Study of Heavy Flavor Physics using e+ e- Collision." News H met Cheon Byung-gu (Department of Physics) to hear more about New Physics. The Standard Model is a theory describing three of the four fundamental forces in the universe, which are the electromagnetic, weak, and strong interactions, not including the gravitational force, along with classifying all known elementary particles This has been believed to be consistent due to successfully providing all experimental predictions, but leaves certain phenomena, such as dark matter and dark energy, unexplained. Therefore, this signifies there is a certain particle that has not yet been discovered and yet must be in existence. Cheon, therefore, is developing and planning to proceed with research through a Belle Ⅱ experiment, to search for this very particle. Cheon proceeds with his experiment through colliding an electron and a positron together to uncover a new particle through rare decay events. They are so extremely small that making these two particles collide is extremely difficult; therefore, it can only be done using special vehicles, the SuperKEKB collider and the Belle Ⅱ detector, which is a kind of microscope capable of seeing objects smaller than a nucleus. Once these new particles are discovered, they could provide the foundation for a novel theory named New Physics, beyond the Standard Model. An image of an electron and a positron colliding, making an occurance of new particles seen as blue lines. (Photo courtesy of Cheon) The Super KEKB shoots countless electrons from one side and positrons from the other side, providing an instantaneous luminosity 40 times higher than that of the previous KEKB collider. Then the Belle Ⅱ detector identifies the particles, using seven kinds of sub-detector systems, including a calorimeter trigger system, that selects events that are valuable enough to investigate further. The researchers could have better sorted sets of events to analyze through this detector at real time operation, which Hanyang University group is leading its own independent line. Cheon’s final goal is to find a New Physics phenomenon beyond the current Standard Model through the Belle Ⅱ. These physical studies might not look like something that could directly be connected to everyday life. However, much of our abundant technology in our life has its foundation in physics. “Medical technological skills such as X-ray, CT, and PET detectors all started with knowledge of physics. In the field of physics, new discoveries and new acknowledgements contribute to the mental wealth of humankind,” said Cheon. "Don't be afraid to show your abilities as a world leader!" Cheon is currently working not only as a researcher, but also continues his lectures and manages academic affairs as the dean of the Department of Physics. He has online meetings with researchers in Japan every week to continue his research, trying to let his students improve to be talented people who can contribute to society. “I wish to provide my students with an environment where they can work with foreign researchers. I hope all Hanyangians in the 21st century will also be willing to look not only at Korea, but to the whole world.” On Jung-yun jessica0818@hanyang.ac.kr Photos by Kang Cho-hyun

2018-05 10

[Academics][Excellent R&D] Weaving Technology into the Fibers of Our Lives

The development of smart technology has brought forth a spectacular display of new products in recent years. Under the common label "smart," smartphones, smartwatches, smart homes and other technology used to gather, process, and analyze massive amounts of data have now seeped into some of the most critical parts of our daily lives. In fact, the only limit on the ways of utilizing this technology is our imaginations. In this sense, Professor Bae Ji-hyun (Department of Clothing and Textiles) has made a new attempt to tear down another wall between smart technology and an essential component of our lives: clothing. Introducing the clothes of the future In essence, Bae’s research is an adaptation of wearable devices. Specifically, she aims to introduce electronic devices to our everyday clothing. Among a diverse array of available options, this research targets the field of healthcare. The idea is that by planting electronic devices in our clothes, we can codify data such as bio-signals, physical movements, or even environmental changes to monitor our health status. Generally speaking, clothing and electronic devices intuitively dawn on us as two very disparate domains. This probably has to do with the nature of clothing, which necessitates regular washing, as well as the imaginable discomfort of having metallic devices attached to our clothes. So how does Bae plan to overcome this fixation? The secret is in the fabric. Bae Ji-hyun (Department of Clothing and Textiles) uses a prototype glove to give an explanation of her research. The functional fibers in the glove allow movements to be detected and transmitted in the form of electrical signals. In the big picture of introducing electronic devices to clothing, Bae’s specific area of research is the development of functional fibers that can act as sensors. Furthermore, she has to design the textile organization in a way that allows it to be woven into a wearable form. By endowing fiber, the most basic unit of clothing, with the ability to react to stimuli such as light, movement, and temperature, we could use clothing to transmit, store, and analyze a variety of changes. According to Bae, the most prominent method to enable this function is by mixing conductive macromolecule particles or nano-particles in the process of weaving the fiber strands. Another common method is to coat ordinary thread, such as nylon or silk, with functional substances. Although Bae’s research is only in its initial stage, the projected benefits of the study raise great anticipation. For one, it will bring an immense improvement to the quality of healthcare for the elderly. This is especially timely considering the growth of the elderly population in our society. Not only will smart clothes reduce the cost of healthcare for retired citizens, it will provide higher efficiency by constantly monitoring and diagnosing the state of the wearer. It can also be used to service the disadvantaged such as the monitoring of infants or people with disabilities. Bae also expressed the hope of adapting this new technology to assist the activities of people working under dangerous conditions, such as soldiers or fire fighters, to improve their safety. As previously mentioned, the ways in which the technology can be used is only limited by our imaginations. (a) The sensor part of the glove woven with conductive fiber (b) The change of resistance value following the movement of the finger (c) Demonstration of a sign language detection system using the conductive-fiber based glove (Photo courtesy of Bae) The background story It has only been a year since Bae was recruited as a professor at Hanyang University. Prior to the position as a professor, she worked at an electronics company. Having earned her degree in textile engineering, Bae became immersed in the relationship between textiles and electronic technology while working at the firm. “Once I saw the connection, there were so many possibilities that became obvious to me," answered Bae. Through her previous firm, she was able to participate in a government project to develop wearable devices, providing her with an insight into the prospect of the technology. According to Bae, the hardest part of her research so far has been the novelty of the field. As is true in the case of most technologies these days, her research requires extensive collaboration with other fields. For the immediate research of smart clothes, the fields of electronic engineering and textiles are crucial. Furthermore, as the target of her research is the field of healthcare, some medical insight is also required. Other than that, convergence with a wide scope of academic fields is necessary in order to consider the subsidiary details of the research, such as the environmental impact of the product or the economic costs of commercializing the technology. However, a lack of public interest in the field makes it difficult for Bae to secure opportunities for cooperation with other fields. Although most of Bae's existing joint research projects are done through external networks, she hopes that internal convergence studies at Hanyang will also take place soon. Efforts as an educator Despite the difficulties of her research, Bae confessed that the hardest part of her job is teaching students. As she had no prior experience of interacting with pupils, she devotes a significant amount of her hours to understanding the needs of her students. “I believe that my current priority is to figure out how to be a good professor to my students,” added Bae. Bae wants to encourage students to maintain an open attitude when communicating with others. “Even in joint research, you need to have respect for others’ expertise in their respective fields, as well as an open mind to approach a common problem from diverse directions.” Bae argued that the same holds true for human interaction, which is an important lesson to take to heart when entering society. In the end, she believes that the synergy created from interactions and convergence is what provides us with the momentum to grow. Lee Chang-hyun pizz1125@hanyang.ac.kr Photos by Lee Jin-myung

2018-04 30

[Academics][Researcher of the Month] Applying Terahertz to Weld-Line Detection

The weld-line among moulding injected plastic products have long presented a challenge in the production of plastic. Destruction of a specific plastic product has been considered necessary in the process of examining any existing weld-lines within the material. However, based on his newly released paper "Terahertz time-domain spectroscopy of weld-line defects formed during an injection moulding process," Kim Hak-sung (Mechanical Engineering) has coined the concept of applying terahertz radiation in this examination process. Based upon the terahertz time domain spectroscopy (THz-TDS), Kim has introduced a novel method of detecting weld-lines among moulding injected plastic products in a nondestructive manner. The THz-TDS technique In order to understand the THz-TDS system, one must become familiar with the actual concept of terahertz. Terahertz refers to a frequency unit of electromagnetic waves, counting up to one trillion cycles per second. Its long microwaves and wavelengths provide it a high permeability which allows terahertz to surpass materials other than metal. This high permeability leads to the THz-TDS, a spectroscopic technique in which the properties of matter are examined through different phases of terahertz radiation. In short, when shot at a specific target, the phases of terahertz radiation differ while surpassing different materials. Professor Kim Hak-sung (Mechanical Engineering) explained the benefits of terahertz radiation and how it can be applied to more practical fields. Although THz-TDS was an already-existing technique, it was Kim who applied it to the more practical field of finding weld-lines among plastic products. Weld-lines are lines that occur around areas where two flow fronts meet, yet are unstably "welded" together in the moulding process. These weld-lines cause weak areas among the moulded part, which may lead to a breakage of the product when the part is under pressure. Until now, the inevitable destruction of the whole product has been regarded as the only method of scrutinizing the existence of weld-lines. However, Kim has introduced a new method, which allows the weld-lines to be detected without breakage. Applying THz-TDS to weld-line detection As mentioned above, different phases of terahertz radiation occur when surpassing different materials. This variation of phases allows one to determine the specific material that the terahertz radiation is currently transcending through. Thus, when shooting terahertz radiation at moulding injected plastic products, the distinctions that occur among phases would be the areas where weld-lines, different layers than other parts of the product, are detected. This would eliminate the necessity of the current destructive weld-line determination process, as simply shooting terahertz radiation at the plastic products enables the investigation method to be possible without any force input. The phases of terahertz radiation differ according to the existence of weld-lines, which allows the detection of such weld-lines within plastic products. (Photo courtesy of Kim) Kim implemented a scanning method when conducting experiments to prove his theory. While attaching a mirror to the terahertz radiation, he moved the specimens according to their reflections. In order to make the reflections happen, the mirror was given a metalized-coating, considering the fact that terahertz surpasses all materials but metal. He managed to make a reflective-equipment that made the reflections occur on a much faster period, which allowed him to gather more results in a shorter time. According to Kim, the equipment is in its initial stage, yet developments are still being made towards totally eliminating minor errors. Hardships and future plans Despite achieving striking results, Kim also had hardships while conducting his research. Kim is a professor in the department of mechanical engineering, whereas terahertz research is related to the field of electronic engineering. Conducting research in a totally different field irrelevant to his major resulted in Kim having to look into two completely distinctive areas. However, he continued his research with only his students, without engaging in any form of joint research with others from departments in more closely-related fields. Oh Gyung-hwan, one of Kim's student assistants and co-leaders of this research, and Kim (left and right) commented on the importance of one finding his or her own reasons for conducting research and remarked that they want to help students find such causes. Such thought may result from Kim’s belief that research must be conducted in a positive manner. Kim mentioned, “I want my students to find their own reasons of pursuing specific research, while being proud of their achievements at the same time." He also added that this research was also conducted worldwide, and hence, his students should be proud of the significant results their global research. As for his future plans, Kim declaimed, “Despite my hardships in this study, I would like to do more research in a variety of other fields, while maintaining a firm stance within my major of mechanical engineering.” Choi Seo-yong tjdyd1@hanyang.ac.kr Photos by Choi Min-ju