Development of PM2.5 management strategy in the industrial city of Ulsan : A comprehensive approach to understanding the risk and sources of PM2.5

Sang-Jin Lee Ulsan National Institute of Science and Technology 2024 국내박사

Factors Influencing the Public Acceptance of the Floating Offshore Wind Farm Development in Ulsan

Seonghee Yang Ulsan National Institute of Science and Technology 2022 국내석사

This thesis investigates the determinants of the public acceptance of the floating offshore wind farm development in Ulsan, highlighting the role of the community profit-sharing schemes. The Ulsan project is currently the largest floating offshore wind farm plan in the world and aims to install a total capacity of 9GW by 2030. As many cases at home and abroad demonstrated, public acceptance is a key success factor of large-scale renewable projects. Although there are many factors influencing public acceptance, profit-sharing schemes for local communities have recently drawn a significant attention from local residents and policy-makers alike. This thesis examines the individual effects of profit-sharing schemes and further their joint effects with other factors such as prior knowledge, trust, distributive and procedural justice, perceived risks and perceived costs, and perceived benefits. We collected data from a survey of 500 individuals who live in Ulsan and analyzed the data using OLS. The theoretical and policy implications of our empirical findings are discussed.

Bioinspired composite cilia for active and passive droplet control

Sang-Hyeon Lee Ulsan National Institute of Science and Technology 2022 국내박사

Water droplets and wetting phenomena on various surfaces are ubiquitous in nature and pose significant challenges in various fields. Water droplets in contact with surfaces for a long period lead to the formation of biofilms and cause hygiene problems. They also cause surface icing and metal corrosion, which affect social infrastructure. In addition, water droplets on transparent surfaces degrade optical performance, such as light transmission. Various techniques have been used to address these problems, such as mechanical removal, chemical fluid release (de-icing, anti-corrosion, biocidal, etc.), and Joule heating. However, these techniques are ineffective, expensive, and environmentally harmful. Bioinspired droplet control technology has emerged as a fundamental solution to various problems caused by water droplets and the wetting phenomena. Inspired by living organisms, surfaces with nano/micro-scale cilia structures have been proposed as excellent candidates for droplet control. Multiscale cilia structure-based surfaces can solve the existing problems by maximizing the surface wettability to control the wetting / de-wetting behavior of droplets. A superhydrophobic surface, consisting of cilia array and hydrophobic material, removes the droplets from the surfaces and minimizes the contact between them, preventing freezing and corrosion. In contrast, a superhydrophilic surface, made of cilia array and hydrophilic material, spreads the droplets and forms a thin and continuous aqueous film on the surface, preventing settling of impurities and fogging caused by droplet condensation. However, single-strategy droplet control technologies based on such a simple structure still have several limitations. For example, if a typical superhydrophobic surface based on a cilia array is horizontally arranged, the droplets cannot be removed without additional external force. Moreover, superhydrophilic surfaces with cilia arrays are susceptible to fouling by airborne contaminants, such as dust, due to high surface energy of the hydrophilic materials. Recently, research has been conducted on active and passive droplet control technologies using functional materials to solve the problems caused by wetting phenomena and to address the limitations of the existing technology. First, active droplet control techniques based on stimuli-responsive materials can modulate the droplet manipulation and drop bouncing dynamics using various external stimuli. Among the stimuli-responsive materials, a magneto-responsive composite material was chosen as the primary functional material for active droplet control because it has a fast response speed and doesn’t require additional external power source for precise deformation control. The surface morphology of the magneto-responsive composite elastomer can be actively controlled using a magnet, which enables droplet manipulation and easy removal of droplets from the surface. Second, passive droplet control techniques based on anti-fouling materials can prevent a wide range of contamination such as airborne and waterborne pollution by the hydration barrier and weak adhesion. Second, owing to hydration barrier and weak adhesion, passive droplet control techniques based on anti-fouling materials can prevent a wide range of contamination such as airborne and waterborne pollution. An amphiphilic copolymer with both hydrophilic and hydrophobic segments is also being considered as a suitable material for passive droplet spreading. It was found that an amphiphilic copolymer has droplet spreading ability and exhibits “fouling-resistant” property in the hydrophilic segment and the “fouling-release” property in the hydrophobic segment. Therefore, based on their unique properties, amphiphilic material-based surfaces exhibit excellent anti-fogging and anti-biofouling properties. In addition, these surfaces can prevent external contaminants from firmly adhering to the surface and reduce surface contamination. However, single-strategy active and passive droplet control technologies based only on functional materials also have some limitations. Owing to the lack of de-wetting or wetting properties, planar surfaces composed of only functional materials without multiscale cilia structures do not exhibit a sufficiently high capability to remove or spread droplets on the surface. For example, droplets may adhere to a magneto-responsive composite planar surface because of insufficient hydrophobicity. In addition, it is not easy to spread droplets over a wide area on an amphiphilic planar surface because of its insufficient wetting performance. Many previous studies on droplet control focused on single-strategy techniques, such as typical superwetting surfaces based on multiscale structures or planar surfaces based on functional materials. However, such single-strategy approaches to droplet control have many limitations. Therefore, new strategies in multi-approaches, that integrate both strategies in approaches of multiscale architectures and functional composite materials, are needed to overcome the problems of existing technologies. We proposed a bioinspired magneto-responsive cilia array for active droplet control based on a superhydrophobic and hierarchical cilia array composed of a magneto-responsive composite elastomer. In this study, the dynamic cilia array showed robust droplet shedding performance by actively controllable multimodal drop bouncing dynamics and precise droplet manipulation. Furthermore, it exhibited remarkable anti-icing properties compared to conventional technologies. We also presented a bioinspired amphiphilic copolymer nanocilia array for passive droplet spreading. The hybrid of hydrophilic hydrogel, hydrophobic lubricant, and nanostructures showed significantly enhanced spreading ability due to the synergetic integration of the amphiphilic copolymer and nanoscale cilia array. The amphiphilic nanocilia hybrid exhibited a pronounced anti-fogging performance due to its water-spreading properties and retardation of droplet nucleation. It also exhibited notable anti-biofouling performance by integrating fouling-resistant, fouling-release, and foulant-killing mechanisms.

Differences in Public Perception of Geothermal Energy in Korea : National vs. Local

Hae-In Baek Ulsan National Institute of Science and Technology 2021 국내석사

This study investigates the public perception differences in geothermal power generation at the national and local levels through media content analysis and survey analysis. Media content analysis results indicated that the previously positive media framing for environment and technology drastically changed to a negative framing of risk after the Pohang earthquake, and there were no significant differences between national and local coverage. However, survey data showed that the local perception of geothermal energy was significantly more negative than that at the national level. The proximity to the earthquake epicenter was negatively correlated with the perception of geothermal energy. Regarding energy source preferences among local residents, geothermal power plants and nuclear power plants were placed in the same category. Pohang residents seemed to associate geothermal power plants with nuclear power plants in terms of risk discourse. They viewed several similarities, i.e., high risks, between the two technologies. As a result of the Pohang earthquakes being byproducts of geothermal power generation, geothermal energy is recognized as a threat or potential danger rather than a risk-free and environment-friendly renewable energy source. To reduce the renewable energy perception gap between the national public opinion and the locals’ view, sufficient and carefully planned communications with local residents are required. Before introducing renewable energy to a region, a strategically planned science/technology education outreach venture accompanied by an honest risk assessment for the locals is essential.

Development of decision support systems for technology and business opportunity analysis

Gyumin Lee Ulsan National Institute of Science and Technology 2023 국내박사

Monolithic Trantenna : Terahertz Detectors Based on Silicon Ring-Gate Plasmonic Field Effect Transistor

E-San Jang Ulsan National Institute of Science and Technology 2021 국내박사

In this dissertation, the Monolithic Trantenna (Transistor + Antenna) as high-performance terahertz(THz) detector; based on Silicon (Si) nano-ring type field-effect transistor (FET) is demonstrated for sub-THz imaging technology. And its operation based on highly localized plasmonic wave in the scalable ring-channel is analyzed by using technology computer-aided design (TCAD) and electromagnetic (EM) wave solver tools. The ring-FET is fabricated by Si-CMOS process and we obtained total 900-fold photoresponse ( u) enhancement in on-chip ground-signal-ground (GSG) probing measurement setup. For the high capacitance asymmetry a = Cgd=Cgs, the inner circle diameter (din) is scaled down to 130 nm under the parasitic resistance limit case. Furthermore, the u asymmetry originated by different ground(gnd) source configuration between (i) gnd-out or (ii) gnd-in of the ring-gate is analyzed for the higher responsivity Rv and lower channel thermal noise. Therefore, by taking (i) gnd-out source, we characterized 5-times additional enhancement followed by the 180-times from din and a scaling. Finally, based on the highly localized plasmonic ring-FET, high performance compact THz detector is demonstrated in free-space by using the compact monolithic Trantenna structure without the external amplifier gain. For a higher THz wave power absorption design, the conductive circular active area of ring-FET is designed as circular patch antenna with resonant frequency and the THz wave is absorbed directly in the ring-channel for the plasmonic rectification without the lossy feeding network. As a result, The record-high RV over 12 kV/W and low noise equivalent power of sub-10 pW/Hz0:5 without external gain are experimentally achieved through free-space 0.12 THz illumination. Moreover, free-space THz imaging experiments shows polarization-independent imaging results due to an isotropic circular antenna characteristic.

Measuring Public Life Through Digital Technologies: Investigating the Use of WiFi Sensing for Enhancing Public Space

Juhyeon Park Ulsan National Institute of Science and Technology 2022 국내박사

Effective and Efficient Patch Validation via Differential Fuzzing

Eui Bin Bae Ulsan National Institute of Science and Technology 2022 국내석사

Developments in APR(automatic program repair) technology have made it possible to automate the creation of patches. However, due to the loose precision(the current technology only recognizes a patch if it passed a test), it is still left up to the developer to determine whether the generated patch is correct. Accordingly, techniques for determining whether a generated patch is correct are being studied these days. Existing methods mainly score how likely a patch is correct. The calculated score is compared with a predetermined threshold to determine whether the patch is correct. However, it is difficult to improve both recall and precision no matter how the threshold is set. For example, in the case of ODS, it shows a problem that filters out many bad patches, but also filters out many correct patches. In this study, we try to solve this problem through an evidence-based method. We take different results before and after the patch as the minimum condition for determining that the patch is wrong. In this condition, if the input that derives different results represents the passing test, the different test results can be the evidence for showing that the patch is incorrect. We use Differential Fuzzing technology to find program inputs that have different results before and after patching. Also, in order to figure out whether the found input represents a passing test, we use the TEST-SIM+ heuristic, which is an improved version of the existing TEST-SIM heuristic. Finally, we develop a purging technology specialized for TEST-SIM+ technology.

A Gene-Centric Perspective of Scientific and Technological Innovations

Woochul Jung Ulsan National Institute of Science and Technology 2023 국내석사

유전자와 유전자 산물에 대한 연구는 현대 생명공학의 기초가 되며, 의학, 농업, 식량산업, 에너지 공급, 환경 정화 등 여러 분야로 응용이 가능한 것으로 알려져 있다. 이러한 과학적 발견들과 기술 혁신을 유전자 중심의 관점에서 거시적으로 조사하고자, 본 논문에서는 연구 논문과 특허에 대한 대규모 선별이 진행되었다. 각 유전자가 갖는 과학적 파급력을 보기 위해서 PubMed에서 접근 가능한 연구 논문 중 제목과 초록에 유전자 또는 유전자 산물이 언급된 자료들을 수집하였다. 기술 혁신 부분에 대응하는 자료로는 미국특허청(USPTO)에서 공개된 특허 출판물이 수집되었다. 문헌 자료 선별과 함께, 유럽 생물정보학 연구소에서 관리하는 UniProt 협의체 데이터베이스 중 선별·제공되는 일부 항목들의 유전자-단백질 명칭을 수집하였고, 이는 이후 유전자 간에 지나치게 중복된 명칭이나 두문자어로 인한 혼동을 방지하기 위해 원소가 공유되지 않는 집합들로 일관되게 군집되었다. 결과적으로 제목/초록에 이러한 유전자 항목을 언급한 논문과 특허들의 연도별 수치를 바탕으로 인간 유전체 프로젝트가 시작된 이후의 추세를 보고하였다. 각 유전자 인용 추세는 연구 논문에서와 비교할 때 발명 문헌에서 변동이 더 큰 것으로 보였고, 두 부문 모두 의료 분야에서 유전자 인용에 대한 기여가 두드러졌다. 지금까지 유전자를 인용한 문헌들은 증가 추세였으나 제목이나 초록에 새롭게 언급되는 유전자의 수는 최근들어 감소하였다. 반면, 이미 연구된 유전자들의 새로운 조합들이 활발히 탐구되는 것으로 보이며, 이러한 조합에 자주 포함된 유전자일수록 단순 인용 횟수의 상위권 유전자보다 생명공학의 발전을 잘 설명히는 것으로 보인다. Research on genes and gene products is a foundation of modern biotechnology, and recognized for its applicability in medicine, agriculture, food industry, energy supply, environmental remediation, and many others. To investigate a macroscopic and gene-centric perspective of scientific discoveries and technological innovations, we employed a large-scale curation of research papers and patents. As a raw data to represent the scientific impact of each gene, we collected the entire set of research articles available on PubMed, that have the names of genes or gene products in their title or abstract. The more dedicated literature source, the United States Patent and Trademark Office (USPTO) patent publication, was retrieved as a source data to represent the counterpart in technological innovations. In parallel with this literature curation, the gene symbols were collected from curated subset of UniProt consortium database maintained by European Bioinformatics Institute, and then clustered into the non-overlapping standardized sets to eliminate the overwhelming duplicates and possible contamination by common acronyms. Based on the annual counts of papers or patents whose titles/abstracts include a given gene, we show the overall trends of genetic research since the launch of the Human Genome Project. The gene citation fluctuated more in inventive activity compared to those in the research, while both sides were largely contributed by medicinal discipline. The volume of publications mentioning genes has been increased while the debut of new genes on titles and abstracts has been deflated. In contrast, new combinations of previously-studied genes kept actively explored, and their frequently adopted genes informed biotechnology innovations rather than sheerly top-studied genes.

How Did It Evolve? Developing a Policy Design Experiment for Sustainability Transitions of a National Museum of Modern and Contemporary Art

Hyori Lee Ulsan National Institute of Science and Technology 2023 국내석사

As museums and cultural institutions have responded to the environmental challenges posed by the climate crisis, they have become critical arenas in driving sustainable design practices. Designers can contribute to those communities for sustainability transitions on multiple scales of society and various timelines by using their creative and decisive agency. However, there needs to be more practical knowl- edge of the design approaches for operationalizing sustainability transitions of such institutions. This thesis presents a multi-layered account of the development process of a policy design experiment for sustainability transitions at the National Museum of Modern and Contemporary Art in South Korea. The author retrospectively traced the entire process, conducted interviews with the project team members, including the director and student designers, and performed a thematic analysis to identify how the pro- cess could evolve. The findings suggest that the process of a policy design experiment for sustainability transitions of a public art museum follows a non-linear and complex process intertwined with multiple design activities. This research’s insights can inspire design researchers, practitioners, museums, and cultural institutions seeking systemic and long-term innovation for sustainability.