https://scholar.dgist.ac.kr/handle/20.500.11750/155 Department of Robotics and Mechatronics Engineering, DGIST 2026-10-18T12:41:35Z https://scholar.dgist.ac.kr/handle/20.500.11750/60962 Title: Thermoresponsive Soft and Self-Anchoring Cuff Electrode for Chronic Peripheral Interfaces Author(s): Lee, Seungjun; Park, Byungwook; Eun, Jonghee; Kim, Sohee; Chou, Namsun Abstract: Cuff type neural interfaces are widely used for peripheral nerve stimulation and monitoring. The traditional cuff electrodes typically require sutures or rigid fixation; this can lead to nerve damage and unstable electrode contact, ultimately compromising long-term performance. To address these issues, we developed a thermoresponsive soft and self-anchoring (TSSA) cuff electrode that automatically wraps around nerves in response to body temperature. This functionality is made possible by a shape memory polymer (SMP) substrate designed to soften and deform near physiological temperatures, enabling the electrode to self-close and securely hold without the need for an external force. Additionally, the SMP provides gentle yet stable contact with the nerve, thereby enhancing biocompatibility. In vivo experiments using rat sciatic nerves demonstrated reliable recordings of mechanically evoked nerve responses for 16 weeks, with signal-to-noise ratios reaching approximately 10 and stable impedance profiles. Histological and immunohistochemical analyses showed no significant tissue damage or inflammatory responses caused by the implanted device. By removing the need for sutures and providing a soft, stable contact with the nerve, the cuff electrode represents a safe and durable platform for chronic neural interfacing. The proposed technology holds strong potential for use in prosthetic limbs and bioelectronic medicine. 2026-08-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60956 Title: Discrete exponentially stable prediction-based controller under time delay with application to unmanned helicopters Author(s): Lee, Seong-Min; Song, Jihun; Cho, Yonghyun; Son, Hungsun Abstract: This paper presents a discrete exponentially stable prediction-based controller (DEPC) for discrete time-delay aerial systems subject to significant time delays and external disturbances. Unlike conventional predictors that could not consider future disturbances, the DEPC integrates an exponential stability criterion into the disturbance prediction process, facilitating accurate recursive state prediction. This strategy ensures that the predicted state exponentially converges to the future state, enabling robust tracking and superior disturbance rejection for inherently unstable platforms. The effectiveness of the DEPC is validated through both numerical simulations and comprehensive flight tests on an unmanned helicopter. The DEPC maintains stability under time delays of up to 0.3s in both indoor and outdoor environments. The control performance shows a maximum reduction of 48% in root-mean-square tracking error compared to existing prediction-based controllers, particularly during sinusoidal input trajectory. The results confirm the feasibility and performance of the DEPC for direct implementation on highly agile aerial platforms, even in the presence of significant time delays. 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60953 Title: Facile synthesis of large-Stokes-shift giant CdHgSe/CdHgSeS near-infrared quantum dots via chlorine-mediated Ostwald ripening Author(s): Lee, Gyudong; Park, Sanghwang; Seo, Jongcheol; Lee, Wonseok; Arogundade, Opeyemi H.; Smith, Andrew M.; Choi, Jongmin; Choi, Hongsoo; Lim, Sung Jun Abstract: Giant core/shell quantum dots (GQDs) offer advantages for optoelectronics, including suppressed blinking and reduced Auger recombination, yet thick-shell growth often requires laborious successive ion layer adsorption and reaction (SILAR) cycles. Here we demonstrate a chlorine-mediated controlled Ostwald ripening strategy that transforms NIR-emitting CdHgSe/CdS core/shell seed QDs into giant CdHgSe/CdHgSeS core/gradient-shell QDs in a single post-synthetic step. Seed QDs are prepared by growing a thin (similar to 1.6-monolayer) CdS shell on CdHgSe alloy cores. Injection of CHCl3 at 240 degrees C triggers rapid ripening, in which most seeds dissolve while a minor population grows into GQDs. During ripening, the band-edge absorption feature is strongly attenuated and absorption below similar to 610 nm increases markedly, whereas NIR emission remains centered near similar to 900 nm, yielding a large effective Stokes shift that can mitigate reabsorption in luminescent solar concentrators. HAADF-STEM/EDS and XRD support a compositionally graded shell, while mass spectrometry and numerical simulations are consistent with chlorine-modified surface chemistry and altered monomer solubility/surface tension that accelerate ripening. As a proof of concept, embedding the GQDs in PMMA affords a transparent luminescent solar concentrator prototype with retained NIR emission and favorable spectral overlap with silicon photovoltaics. 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60952 Title: Candle soot-enhanced pyroelectric generator for thermal energy harvesting and self-powered sensing Author(s): Bhosale, Premkumar; Hajra, Sugato; Mistewicz, Krystian; Belal, Mohamed; Kaja, Kushal Ruthvik; Panigrahi, Basanta Kumar; Vittayakorn, Naratip; Kim, Hoe Joon Abstract: In recent years, there has been considerable interest in surface engineering using carbon-based coatings to improve pyroelectric performance. This work demonstrates a straightforward, economical method for a pyroelectric energy generator (PEG) using candle soot as a light-absorbing coating on a widely available PZT-based piezoelectric buzzer. Infrared (IR) lamp-induced thermal excitation was used to comprehensively assess the performance of the soot-coated and pristine PZT piezoelectric buzzer disk. Due to improved photothermal conversion, the coated PEG device exhibits a significant increase in electrical output. When exposed to the IR lamp, the short-circuit current reached approximately 204 nA, while the open-circuit voltage was approximately 4.8 V. Furthermore, under controlled thermal cycling, the device exhibited adjustable output and efficient energy storage. Further, the PEG was shown to be sensitive to temperature changes caused by human activity or the daily use of appliances, as well as to energy harvesting, suggesting its potential for self-powered sensing applications, such as breath monitoring, or converting energy from everyday appliances. Overall, this study presents a simple method to increase pyroelectric device performance efficiency in sensing and sustainable energy applications. 2026-09-30T15:00:00Z