81 research outputs found
Expanding electronics beyond silicon with wide-bandgap, 2D, and ferroelectric materials
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Hanwool Lee, accepted the attached license on 2025-04-17 at 01:00.The student, Hanwool Lee, submitted this Dissertation for approval on 2025-04-17 at 01:08.This Dissertation was approved for publication on 2025-04-18 at 16:08.DSpace SAF Submission Ingestion Package generated from Vireo submission #21812 on 2025-10-19 at 19:53:17This dissertation explores the advancement of microelectronics through novel materials, including two-dimensional (2D) materials, ferroelectric materials, and wide-bandgap semiconductors. These emerging materials enable new functionalities, improve energy efficiency, and enhance stability for various applications. Chapter 1 provides background information for this dissertation, including a brief review of 2D materials, particularly transition metal dichalcogenides (TMDCs). Ferroelectric materials and their device applications are discussed. Additionally, wide-bandgap semiconductors and their advantages are introduced, with a particular focus on gallium nitride (GaN). Chapter 2 explores non-volatile reconfigurable transistors with four-mode operation. Utilizing the strong polarization of epitaxially grown scandium aluminum nitride (ScAlN), a single device can function as an n-type, p-type, always-on, or always-off transistor. The feasibility of these transistors for logic gate applications is demonstrated. Additionally, non-volatile latch operation is presented using van der Waals materials, including ferroelectric copper indium thiophosphate (CIPS) and molybdenum ditelluride (MoTe2). Ferroelectric field-effect transistor (FeFET) with metal-ferroelectric-metal-insulator-semiconductor (MFMIS) structure enables stable memory operation. Using these FeFETs, non-volatile sequential logic operation is demonstrated through a simple latch circuit. Chapter 3 demonstrates the wafer-scale synthesis of MoTe2 using di-tert-butyl telluride ((C4H9)2Te) as the tellurium precursor, along with molybdenum hexacarbonyl (Mo(CO)6) and sputtered molybdenum (Mo) as molybdenum precursors. The successful wafer-scale growth of both 1T' and 2H phases of MoTe2 is presented, with various characterization results confirming the uniformity, phase selectivity, and high crystallinity of the synthesized material. Chapter 4 investigates GaN-based high-electron-mobility transistors (HEMTs) for high-temperature applications. Dielectric stack optimization, gate recess structures, and p-GaN/AlGaN/GaN heterostructures are explored to achieve stable operation up to 500 °C. Optimizing the dielectric stack enhances the breakdown field and device lifetime, while the gate recess and p-GaN/AlGaN/GaN heterostructure enable enhancement-mode operation with improved threshold voltage stability at high temperatures. Chapter 5 concludes this dissertation by summarizing key findings and outlining directions for future research. By integrating emerging materials with innovative design strategies, these studies advance next-generation electronic devices and facilitate their practical implementation in semiconductor technology
Sequential quantum maximum-confidence discrimination
No full textSequential quantum information processing may lie in the peaceful coexistence of no-go theorems on quantum operations, such as the no-cloning theorem, the monogamy of correlations, and the no-signalling principle. In this work, we investigate a sequential scenario of quantum state discrimination with maximum confidence, called maximum-confidence discrimination, which generalizes other strategies such as minimum-error and unambiguous discrimination. We show that sequential discrimination with equally high confidence can be realized if and only if positive-operator-valued measure elements for a maximum-confidence measurement can be unambiguously discriminated, i.e., linearly independent; otherwise, a party will have strictly less confidence in measurement outcomes than the previous one. We investigate the tradeoff between state disturbance and information gain in sequential state discrimination and show that the less guessing probability there is from conclusive outcomes for each party, the more parties can participate in the sequential scenario.
Supplemental Material, sj-pdf-1-her-10.1177_19375867231166080 - Environmental and Mobility Strategies During Early COVID-19: Insights From an Empirical Study Focusing on Park Visitations in El Paso, TX
No full textSupplemental Material, sj-pdf-1-her-10.1177_19375867231166080 for Environmental and Mobility Strategies During Early COVID-19: Insights From an Empirical Study Focusing on Park Visitations in El Paso, TX by Sinan Zhong, Chanam Lee, Jiahe Bian, Samuel D. Towne, Hanwool Lee, Yang Song, Wei Li and Marcia G. Ory in HERD: Health Environments Research & Design Journal</p
Increased Excitatory Synaptic Transmission of Dentate Granule Neurons in Mice Lacking PSD-95-Interacting Adhesion Molecule Neph2/Kirrel3 during the Early Postnatal Period
No full textCopy number variants and point mutations of NEPH2 (also called KIRREL3) gene encoding an immunoglobulin (Ig) superfamily adhesion molecule have been linked to autism spectrum disorders, intellectual disability and neurocognitive delay associated with Jacobsen syndrome, but the physiological roles of Neph2 in the mammalian brain remain largely unknown. Neph2 is highly expressed in the dentate granule (DG) neurons of the hippocampus and is localized in both dendrites and axons. It was recently shown that Neph2 is required for the formation of mossy fiber filopodia, the axon terminal structure of DG neurons forming synapses with GABAergic neurons of CA3. In contrast, however, it is unknown whether Neph2 also has any roles in the postsynaptic compartments of DG neurons. We here report that, through its C-terminal PDZ domain-binding motif, Neph2 directly interacts with postsynaptic density (PSD)-95, an abundant excitatory postsynaptic scaffolding protein. Moreover, Neph2 protein is detected in the brain PSD fraction and interacts with PSD-95 in synaptosomal lysates. Functionally, loss of Neph2 in mice leads to age-specific defects in the synaptic connectivity of DG neurons. Specifically, Neph2−/− mice show significantly increased spontaneous excitatory synaptic events in DG neurons at postnatal week 2 when the endogenous Neph2 protein expression peaks, but show normal excitatory synaptic transmission at postnatal week 3. The evoked excitatory synaptic transmission and synaptic plasticity of medial perforant pathway (MPP)-DG synapses are also normal in Neph2−/− mice at postnatal week 3, further confirming the age-specific synaptic defects. Together, our results provide some evidence for the postsynaptic function of Neph2 in DG neurons during the early postnatal period, which might be implicated in neurodevelopmental and cognitive disorders caused by NEPH2 mutations.
Copyright © 2017 Roh, Choi, Cho, Choi, Park, Cutforth, Chung, Park, Lee, Kim, Lee,
Mo, Rhee, Kim, Ko, Choi, Bae, Shen, Kim and Han. This is an open-access article
distributed under the terms of the Creative Commons Attribution License (CC BY).
The use, distribution and reproduction in other forums is permitted, provided the
original author(s) or licensor are credited and that the original publication in this
journal is cited, in accordance with accepted academic practice. No use, distribution
or reproduction is permitted which does not comply with these terms.
© 2017 Roh, Choi, Cho, Choi, Park, Cutforth, Chung, Park, Lee, Kim, Lee,
Mo, Rhee, Kim, Ko, Choi, Bae, Shen, Kim and Han. This is an open-access article
distributed under the terms of the Creative Commons Attribution License (CC BY).
The use, distribution and reproduction in other forums is permitted, provided the
original author(s) or licensor are credited and that the original publication in this
journal is cited, in accordance with accepted academic practice. No use, distribution
or reproduction is permitted which does not comply with these terms.
Frontiers1321sciescopu
Let's Talk@Clubhouse: Exploring Voice-Centered Social Media Platform and its Opportunities, Challenges, and Design Guidelines
No full text© 2022 ACM.Due to the pandemic, social media has become an essential route to satisfy socializing needs. Expanding from dominant services like Facebook and Instagram, a new wave caused a stir-Clubhouse as a voice-centered social media platform. Despite its worldwide popularity after its launch in 2020, general properties of Clubhouse have not been actively discussed. Accordingly, this study explores Clubhouse's opportunities and challenges as a voice-centered social media through its user experiences. We conducted interviews with regular Clubhouse users (N=26) to gain insight into their motivation, social networking, and conversations. Findings highlight that voice is effective for establishing social relationships via interactivity and intimacy, mutual respect, and convenience from ephemerality. Conversely, users reported patterns of the privacy paradox and the oligopoly of communication. Design guidelines for future voice-centric social media are proposed. Our initial study of Clubhouse will encourage more dialogues on voice-centered social media and its potential as a major platform.N
Metainformation in quantum guessing games
No full textQuantum guessing games offer a structured approach to analyzing quantum information processing, where information is encoded in quantum states and extracted through measurement. An additional aspect of this framework is the influence of partial knowledge about the input on the optimal measurement strategies. This kind of side information can significantly influence the guessing strategy and earlier work has shown that the timing of such side information, whether revealed before or after the measurement, can affect the success probabilities. In this work, we go beyond this established distinction by introducing the concept of metainformation. Metainformation is information about information, and in our context it is knowledge that additional side information of certain type will become later available, even if it is not yet provided. We show that this seemingly subtle difference between having no expectation of further information versus knowing it will arrive can have operational consequences for the guessing task. Our results demonstrate that metainformation can, in certain scenarios, enhance the achievable success probability up to the point that post-measurement side information becomes as useful as prior-measurement side information, while in others it offers no benefit. By formally distinguishing metainformation from actual side information, we uncover a finer structure in the interplay between timing, information, and strategy, offering new insights into the capabilities of quantum systems in information processing tasks.peerReviewe
양자정보처리를 위한 최대 신뢰도 측정
No full text학위논문(박사) - 한국과학기술원 : 전기및전자공학부, 2024.2,[iv, 74 p. :]The problem of quantum state discrimination has its origin in one of the key results in quantum information theory: a single-shot measurement cannot perfectly distinguish non-orthogonal states. It aims to construct strategies to correctly guess which state from an ensemble of states is prepared. For this purpose, one may consider distinct figures of merits, such as an average error in the guessing task. The present thesis considers a maximum-confidence measurement (MCM) that optimizes guessing a state {\it per} a detection event. We present a construction of an MCM for ensembles of quantum states and apply it to the certification of quantum measurements in a semi-device-independent (sDI) scenario, in which details of measurements are not assumed but the working principle must be consistent with an underlying physical theory. We first develop the theoretical framework of finding an MCM for an ensemble. We apply it to qubit states such as geometrically uniform states and noisy symmetric, informationally complete states, which are of particular interest in quantum communication protocols. We then consider an sDI scenario of an MCM in quantum and noncontextual ontological theories and show that an MCM of quantum states can be certified by finding a discrepancy between the abovementioned theories. The outcome statistics that quantum theory can only predict, whereas classical theories fail, may be used to achieve quantum advantages in related information tasks.한국과학기술원 :전기및전자공학부
On the VSI CUSUM Chart for Count Processes and its Implementation with R Package attrCUSUM
No full text- …
