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In phosphor-sensitized-fluorescent organic light-emitting diodes (PSF-OLEDs), triplet excitons generated in the emitting layer (EML) are harvested by the sensitizer and the excitonic energy is efficiently transferred to the fluorescent dopant molecules. Since a phosphorescent sensitizer is typically doped at around 10 wt.%, the sensitizer not only affects cascade energy transfer but also electrical transporting in the PSF-OLEDs. However, the electrical role of phosphorescent metal complex molecules in the EML is unclear. In this study, we report the impact of the phosphorescent sensitizer on the electrical properties of PSF-OLEDs. Through a comprehensive analysis using impedance spectroscopy in conjunction with current density (J)-voltage (V)-luminance (L) properties of the PSF-OLED, it was revealed that 10 wt.% phosphorescent sensitizer forms an electron transporting pathway inside the EML. Thus, the sensitizer molecules transform a unipolar single host into a bipolar mixed host. In other words, the phosphorescent sensitizer is an n-type host in the PSF-OLEDs. As a result, the charge balance and the operating voltage were simultaneously and significantly improved in the PSF-OLEDs.

Recent advancements in deep reinforcement learning for real control tasks have received interest from many researchers and field engineers in a variety of industrial areas. However, in most cases, optimal policies obtained by deep reinforcement learning are difficult to implement on cost-effective and lightweight platforms such as mobile devices. This can be attributed to their computational complexity and excessive memory usage. For this reason, this article proposes an off-policy deep reinforcement learning algorithm called the sparse variational deterministic policy gradient (SVDPG). SVDPG provides highly efficient policy network compression under the standard reinforcement learning framework. The proposed SVDPG integrates Bayesian pruning, which is known as a state-of-the-art neural network compression technique, with the policy update in an actor–critic architecture for reinforcement learning. It is demonstrated that SVDPG achieves a high compression rate of policy networks for continuous control benchmark tasks while preserving a competitive performance. The superiority of SVDPG in low-computing power devices is proven by comparing the level of compression in terms of the memory requirements and computation time on a commercial microcontroller unit. Finally, it is confirmed that the proposed SVDPG is also reliable in real-world scenarios since it can be applied to the swing-up control of an inverted pendulum system.

In this study, we designed and synthesized two blue fluorescence materials using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[b]fluoreno[3,4-d]thiophene substituted anthracene derivatives. To characterize their electroluminescent properties, we fabricated the OLED devices using these two emitting materials. Particularly, a device using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ b]fluoreno[3,4-d]thiophene showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 2.42 cd/A, 1.48 lm/W, 3.08% at 20 mA/cm2, respectively with CIE (x, y) coordinates of (0.15, 0.09) at 8.0 V.

Highly efficient blue fluorescent 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[6,7]indeno[1,2- f]quinoline derivatives, based on benzo-indeno-quinoline and phenylanthracene were designed and synthesized. To test their electroluminescent properties, organic light-emitting diodes (OLEDs) were fabricated with the configuration of indium-tin-oxide (ITO) (150 nm)/4,4′,4″-Tris[2- naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N,N′-di(1-naphthyl)-N,N′-diphenyl-1,1′- biphenyl)4,4′-diamine (NPB) (20 nm)/blue emitting materials (20 nm)/bathophenanthroline (Bphen) (30 nm)/Liq (2 nm)/Al (100 nm). The devices using these blue materials as emitters showed efficient blue emission. Particularly, a device employing 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ 6,7]indeno[1,2-f]quinoline as an emitting layer yielded the best performance with a luminous efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) and the Commission International de L’Eclairge (CIE) coordinates of 4.60 cd/A, 3.07 lm/W, 4.32% at 20 mA/cm2, and (0.16, 0.12) at 8.0 V, respectively.

Active noise control system has received its attention in various technical field such as headphone, motor vehicle, etc. Meanwhile, filtered-x least mean square (FxLMS) algorithm is conventional linear algorithm used in active noise control system. It assumes that acoustic path from the noise source and control source to target area are linear. However, in actual system, the secondary path including a D/A converter, an amplifier, and an actuator may exhibits nonlinear distortion like saturation effects. To cope with this nonlinear effects, functional link artificial neural network (FLANN) has been proposed. FLANN uses nonlinear function expansion filter with FxLMS based control algorithm to control the nonlinear effect. In this paper, noise reduction performance and convergence speed are improved by modifying the conventional FLANN algorithm by decoupling the linear and nonlinear part of noise signal.

Cloud computing provides virtualized information technology (IT) resources to ensure the workflow desired by user at any time and location; it allows users to borrow computing resources such as software, storage, and servers, as per their needs without the requirements of complicated network and server configurations. With the generalization of small embedded sensor devices and the commercialization of the Internet of Things (IoT), short- and long-range wireless network technologies are being developed rapidly, and the demand for deployment of cloud computing for IoT is increasing significantly. Cloud computing, together with IoT technology, can be used to collect and analyse large amounts of data generated from sensor devices, and easily manage heterogeneous IoT devices such as software updates, network flow control, and user management. In cloud computing, attacks on users and servers can be a serious threat to user privacy. Thus, various user authentication schemes have been proposed to prevent different types of attacks. In this paper, we discuss the security and functional weakness of the related user authentication schemes used in cloud computing and propose a new elliptic curve cryptography- (ECC-) based three-factor authentication scheme to overcome the security shortcomings of existing authentication schemes. To confirm the security of the proposed scheme, we conducted both formal and informal analyses. Finally, we compared the performance of the proposed scheme with those of related schemes to verify that the proposed scheme can be deployed in the real world.

In this study, two blue fluorescent using phenylanthracene-substituted furan derivatives were synthesized for organic light-emitting diodes (OLEDs) and subsequently characterized. To study the electroluminescent properties of the materials, OLED devices were fabricated using these two materials as an emissive layer (EML). The device using 7,7-diphenyl-9-(10-phenylanthracen-9-yl)-7H-fluoreno[4,3-b]benzofuran in the emitting layer showed the highest external quantum efficiency (EQE) value, 3.10%. It also showed the maximum luminance efficiency of 2.41 cd/A and maximum power efficiency of 1.90 lm/W with CIE coordinates of (0.15, 0.08).

Federated authentication, such as Google ID, enables users to conveniently access multiple websites using a single login credential. Despite this convenience, securing federated authentication services requires addressing a single point of failure, which can result from using a centralized authentication server. In addition, because the same login credentials are used, anonymity and protection against user impersonation attacks must be ensured. Recently, researchers introduced distributed authentication schemes based on blockchains and smart contracts (SCs) for systems that require high availability and reliability. Data on a blockchain are immutable, and deployed SCs cannot be changed or tampered with. Nonetheless, updates may be necessary to fix programming bugs or modify business logic. Recently, methods for updating SCs to address these issues have been investigated. Therefore, this study proposes a distributed and federated authentication scheme that uses SCs to overcome a single point of failure. Additionally, an updatable SC is designed to fix programming bugs, add to the function of an SC, or modify business logic. ProVerif, which is a widely known cryptographic protocol verification tool, confirms that the proposed scheme can provide protection against various security threats, such as single point of failure, user impersonation attacks, and user anonymity, which is vital in federated authentication services. In addition, the proposed scheme exhibits a performance improvement of 71% compared with other related schemes.

Extremely stable white emission out of a hybrid white quantum dot-organic light-emitting diode (WQD-OLED) was achieved by developing a novel concept of device architecture. The new inverted device structure employs a thermally-evaporated red phosphorescent emitting layer (EML) with an n-type modulation and a multi-stacked hole transporting layer (HTL) on the top of solution-processed ZnO nanoparticles for an electron transporting layer and blue and green QD-mixed EML. The multi-stacked HTL, tris(4-carbazoyl-9-ylphenyl)amine (TCTA)/1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), and the n-type modulation layer, 2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) successfully balanced low-mobility holes with high-mobility electrons, and uniformly distributed the charges across the blue/green QD and red EMLs. In particular, the role of the n-type modulation layer was comprehensively analyzed with impedance spectroscopy and verified to minimize the undesired Auger recombination by excess charges and broaden the recombination zone. Consequently, highly stable white emission (0.32 ± 0.02, 0.31 ± 0.02) in CIExy color coordinates over 4 V operating voltage range (or two decades of current density), 3.92% external quantum efficiency, and 3.83 h device lifetime at 500 cd m−2 up to 50% of the initial luminance (LT50) were simultaneously obtained.

Background: There are still insufficient studies of the relationship between the clinical wear and build angle of the interim crowns fabricated with the DLP 3D printing. The purpose of this study was to evaluate the wear volume in the interim crown fabricated according to the printing angle of DLP 3D printing.Methods: This study included five patients who needed the single crown in the mandible molar. Interim crowns were fabricated directly in the oral cavity with the conventional method. Using a DLP 3D printer, the crowns were fabricated by setting the angles to 0, 45, and 90 degrees. Four fabricated interim crowns, using the conventional method, were randomly delivered to the patients, and used respectively for one week. The intaglio surface of interim crowns before and after use were scanned with a 3D scanner. In addition, volume changes before and after use were measured, and 3D height changes of the occlusal surface were evaluated by calculating the RMS value. Statistical analysis verified the data normality, and each group’s wear volume was evaluated, using One-way ANOVA and Tukey HSD test (α = 0.05).Results: The value was significantly higher at 90 degrees compared to the conventional method and 0 degrees (P < 0.05). There were significantly higher volume change values at 90 degrees compared to the conventional method (P < 0.05). In addition, the interim crowns fabricated with the conventional method showed the lowest changes in the RMS and volume values (P < 0.05).Conclusions: The 90 degrees printing angle is not recommended when interim crowns are fabricated with the DLP 3D printing method.Trial registration: The study protocol was approved by the Kyungpook National University Dental Hospital Institutional Review Board (approval number: KNUDH-2021-11-02-01).

In this study, we synthesized and characterized two novel deep blue emitting materials based on indenoquinoline-substituted phenylanthracene derivatives. Multilayer organic light-emitting diodes were fabricated with the following sequence: indium-tin-oxide (ITO)/4,4′,4″-tris[2-naphthyl(phenyl)amino (2-TNATA)/4,4′-bis(N-N-naphthyl)-N-phenylamino) biphenyl (NPB)/Blue emitting material (1 or 2)/Bathophenanthroline (Bphen)/lithium quinolate (Liq)/Al. A device B using ‘7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-indeno[1,2-f] isoquinoline (2)’ as an emitter showed the efficient emission with the luminous efficiency, power efficiency, and external quantum efficiency of 2.30 cd/A, 1.02 lm/W, 2.94% at 20 mA/cm2, respectively. This device exhibited deep-blue emission with the Commission Internationale De LÉnclairage (CIE) coordinates of (0.16, 0.08) and λmax = 436 nm at 8.0 V.

The purpose of this study is to examine the relationship between leisure activities and an individual’s quality of life. Specifically, the study seeks to outline how engaging in leisure activities,...

This article proposes a new interference-compensating magnetometer calibration scheme aided by a gyroscope sensor, which could reduce the effect of induced magnetic interference due to nearby onboard current flow. By using the innovation process and a linear matrix inequality approach, mean and variance of the induced magnetic interference are estimated to ensure that their physical meaningful values are taken to be closest to the empirically measured ones. The values are reflected in the update step of the extended Kalman filter in order to accurately estimate the calibration parameters and the corresponding direction. Results of experiments performed using a real unmanned aerial vehicle (UAV) demonstrate that the proposed calibration scheme compensates well for the disturbing magnetic interference arising from the UAV's onboard current and hence reduces the estimation error of its yaw angle, or its heading direction, by approximately two-thirds of that obtained using the existing scheme.

In this study, we designed and synthesized two blue fluorescence materials using phenylanthracenesubstituted-indenoquinoline derivatives by Suzuki coupling reaction for organic light-emitting diodes (OLEDs). In order to study their electroluminescent properties, we fabricated the OLED devices using these two materials as emissive layer (EML) with the following sequence: indium-tin-oxide (ITO, 180 nm)/4,4′,4″-tris[2-naphthyl(phenyl)-amino]triphenylamine (2-TNATA, 30 nm)/N,N′-diphenyl-N,N′-(2-napthyl)-(1,1′-phenyl)-4,4′-diamine (NPB, 20 nm)/Blue emitting materials (20 nm)/4,7-Diphenyl-1,10-phenanthroline (Bphen, 30 nm)/lithium quinolate (Liq, 2 nm)/Al (100 nm). In particular, a device using 11,11-dimethyl-3-(10-phenylanthracen-9-yl)-11H-Indeno[1,2-b]quinoline in emitting layer showed luminous efficiency, power efficiency, and external quantum efficiency of 2.18 cd/A, 1.10 lm/W, 2.20% at 20 mA/cm2, respectively, with Commission Internationale d’Énclairage (CIE) coordinates of (0.15, 0.11) at 8.0 V.