김재현 교수

) in a broad range of wavelengths (365 to 1310 nm). On the basis of these technologies, a wavelength discriminable phototransistor circuit array (>600 phototransistors) was implemented on a skin-like soft platform, which is expected to be a versatile and scalable approach for wide spectral image sensors and human-oriented biological devices.

Recently, photonic technologies have attracted lots of interests in the demand of high‐performance sensor devices. In particular, multifunctional photodetectors based on low‐dimensional nanomaterials have enabled to address complex environmental conditions and data processing for wide range of emerging applications, such as soft robotics, biomedical devices, and neuromorphic computing hardware, translating into mechanically flexible platforms that can offer reliable information. Semiconducting q

The urban aerial mobility (UAM) system, such as drone taxi or air taxi, is one of future on-demand transportation networks. Among them, electric vertical takeoff and landing (eVTOL) is one of UAM systems that is for identifying the locations of passengers, flying to the positions where the passengers are located, loading the passengers, and delivering the passengers to their destinations. In this paper, we propose a distributed deep reinforcement learning where the agents are formulated as eVTOL

Abstract Color‐selective multifunctional and multiplexed photodetectors have attracted considerable interest with the increasing demand for color filter‐free optoelectronics which can simultaneously process multispectral signal via minimized system complexity. The low efficiency of color‐filter technology and conventional laterally pixelated photodetector array structures often limit opportunities for widespread realization of high‐density photodetectors. Here, low‐temperature solution‐processed

Abstract The emergence of high-form-factor electronics has led to a demand for high-density integration of inorganic thin-film devices and circuits with full stretchability. However, the intrinsic stiffness and brittleness of inorganic materials have impeded their utilization in free-form electronics. Here, we demonstrate highly integrated strain-insensitive stretchable metal-oxide transistors and circuitry (442 transistors/cm 2 ) via a photolithography-based bottom-up approach, where transistor

New emerging low-dimensional such as 0D, 1D, and 2D nanomaterials have attracted tremendous research interests in various fields of state-of-the-art electronics, optoelectronics, and photonic applications due to their unique structural features and associated electronic, mechanical, and optical properties as well as high-throughput fabrication for large-area and low-cost production and integration. Particularly, photodetectors which transform light to electrical signals are one of the key compon

In the wireless sensor networks (WSNs), Synchronous approaches share the schedule information that specifies the cycle of active and sleep period by the control packets. On the other hand, asynchronous approaches do not exchange the synchronization information to send or receive data. Instead, they employ preamble sampling to do that. In this paper, we compare and analyze synchronous and asynchronous MAC protocols for WSNs with our two proposed schemes (AD-MAC and AS-MAC). Our proposed schemes p

A heterogeneous network (HetNet) is a network topology composed by deploying multiple HetNets under the coverage of macro cells (MCs). It can improve network throughput, extend cell coverage, and offload network traffic; for example, the network traffic of a 5G mobile communications network. A HetNet involves a mix of radio technologies and various cell types working together seamlessly. In a HetNet, coordination between MCs and small cells (SCs) has a positive impact on the performance of the n

The aim of this study was to apply iron oxide nanoparticle-chitosan (ION-chitosan) composites to phosphate removal from natural water collected from the Seoho Stream in Suwon, Republic of Korea. Laboratory batch experiments showed that phosphate removal by the ION-chitosan composites was not sensitive to pH changes between pH values of 5.0 and 9.0. During six cycles of adsorption-desorption, the composites could be successfully regenerated with 5 mM NaOH solution and reused for phosphate removal

Green tide, which is a serious water pollution problem, is caused by the complex relationships of various factors, such as flow rate, several water quality indicators, and weather. Because the existing methods are not suitable for identifying these relationships and making accurate predictions, a new system and algorithm is required to predict the green tide phenomenon and also minimize the related damage before the green tide occurs. For this purpose, we consider a new network model using smart

Quantum dot (QD)-based optoelectronics have received great interest for versatile applications because of their excellent photosensitivity, facile solution processability, and the wide range of band gap tunability. In addition, QD-based hybrid devices, which are combined with various high-mobility semiconductors, have been actively researched to enhance the optoelectronic characteristics and maximize the zero-dimensional structural advantages, such as tunable band gap and high light absorption.

In this paper, a deep learning-based successive interference cancellation (SIC) scheme for use in nonorthogonal multiple access (NOMA) communication systems is investigated. NOMA has become a notable technique in the field of mobile wireless communication because of its capacity to overcome orthogonality, unlike a conventional orthogonal frequency division multiple access (OFDMA) communication system. In NOMA communication systems, SIC is one of the decoding schemes applied at receivers for down