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Dong-Hoon Lee

Publications and source records attributed to Dong-Hoon Lee.

4 recordsLinked to original sources

Towards Personalized Brain-Computer Interface Application Based on Endogenous EEG Paradigms

In this paper, we propose a conceptual framework for personalized brain-computer interface (BCI) applications, which can offer an enhanced user experience by customizing services to individual preferences and needs, based on endogenous electroencephalography (EEG) paradigms including motor imagery (MI), speech imagery (SI), and visual imagery. The framework includes two essential components: user identification and intention classification, which enable personalized services by identifying individual users and recognizing their intended actions through EEG signals. We validate the feasibility of our framework using a private EEG dataset collected from eight subjects, employing the ShallowConvNet architecture to decode EEG features. The experimental results demonstrate that user identification achieved an average classification accuracy of 0.995, while intention classification achieved 0.47 accuracy across all paradigms, with MI demonstrating the best performance. These findings indicate that EEG signals can effectively support personalized BCI applications, offering robust identification and reliable intention decoding, especially for MI and SI.

cs.HC

Characterization of single photon sources for radiometry applications at room temperature

A single photon source with high repeatability and low uncertainties is the key element for few-photon metrology based on photon numbers. While low photon number fluctuations and high repeatability are important figures for qualification as a standard light source, these characteristics are limited in single photon emitters by some malicious phenomena like blinking or internal relaxations to varying degrees in different materials. This study seeks to characterize photon number fluctuations and repeatability for radiometry applications at room temperature. For generality in this study, we collected photon statistics data with various single photon emitters of $g^{(2)}(0) < 1$ at low excitation power and room temperature in three material platforms: silicon vacancy in diamond, defects in GaN, and vacancy in hBN. We found common factors related with the relaxation times of the internal states that indirectly affect photon number stability. We observed a high stability of photon number with defects in GaN due to faster relaxations compared with vacancies in hBN, which on the other hand produced high rates ($> 10^6$) of photons per second. Finally, we demonstrate repeatable radiant flux measurements of a bright hBN single photon emitter for a wide radiant flux range from a few tens of femtowatts to one picowatt.

physics.optics

Modular system for fluorescence-based single photon generation using retro-reflector

Apparatus for fluorescence-based single photon generation includes collection optics and various setups for characterization. Managing this system often reveals complexity in such a way that adjusting in a small region changes optimal alignments of others. We suggest here a modular system, where the optimal alignment is given to each compartment and tested independently. Based on this concept, we built a system for single photon generation with fluorescence center in hexagonal boron nitride nano-flake, advantageous for scaling up the number of single mode fiber output and a high degree of stability. The system allowed for a practical use of single photon stream extended over an hour with a uniform count rate of small fluctuation levels.

physics.optics

Experimental Realization of a Four-Photon Seven-Qubit Graph State for One-Way Quantum Computation

We propose and demonstrate the scaling up of photonic graph state through path qubit fusion. Two path qubits from separate two-photon four-qubit states are fused to generate a two-dimensional seven-qubit graph state composed of polarization and path qubits. Genuine seven-qubit entanglement is verified by evaluating the witness operator. Six qubits from the graph state are used to execute the general two-qubit Deutsch-Jozsa algorithm with a success probability greater than 90%.

quant-ph