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Functional encryption (FE) is a novel cryptographic paradigm. In comparison to conventional encryption schemes, FE allows producing secret keys $$sk_f$$ corresponding to a function f that decrypt encryptions of $$x_0$$ to $$f(x_0)$$ . Recently, Lin proposed FE for arbitrary degree polynomials from the SXDH assumption to an exact multilinear map (CRYPTO’17). However, there is no concrete instantiation of the scheme in the absence of an exact multilinear map. Although Lin’s FE can be instantiated by noisy multilinear maps such as the GGH13, CLT13, and GGH15 schemes, the security of FE instantiated by noisy multilinear maps is unclear. In this paper, we point out the weakness of the Lin’s FE when it is instantiated by well-known candidates of noisy multilinear maps. In other words, we present a polynomial time attack of the FE on each noisy multilinear map. In the proposed method, our attack captures Lin’s FE for arbitrary degree polynomials instantiated by GGH13 and CLT13 and is also applicable to FE for polynomials of degree $$O(\log _2 \lambda )$$ when instantiated by GGH15 under the current parameters where $$\lambda $$ is the security parameter.

Using the first set of individual compensation and public data for senior executives in South Korea, we document direct evidence on the level, construction, and mechanisms of CEO remuneration in So...

We demonstrate a high-speed light fidelity (LiFi) communication system deploying ultra-high brightness laser-based white light illumination sources in a surface mount device (SMD) packaging platform. The LiFi transmitter SMD source provides 450 lumens of white light output with a brightness of 1000 cd/mm2 in a dual wavelength configuration comprising blue and infrared (IR) emitting laser diodes within the SMD. First, we present high-speed data transmission beyond 25 Gbit/s over a 3 meter channel distance with the combined data rates from the blue and IR lasers in the single SMD. Next, we present a 2.8 Gbit/s data rate with the dual wavelength laser SMD light source using a side-emissive fiber as the transmitter. This work proves the viability of LiFi systems deploying laser-based white light sources operating at very high data rates with the visible light and communication signal delivered in conventional free-space transmission architectures along with novel configurations using side-emitting fibers.

The released NOx during fuel combustion is one of the major air pollutants, directly related to acid rain and photochemical smog. At present, there is not an economical and effective method of inhibiting NOx emission from sintering flue gas. Therefore, controlling the conditions of fuel combustion is extremely required for the reduction in NOx. The current research investigated the effects of different combustion parameters on the formation of NOx for three type of coals. The formation of NOx decreased with increasing temperature and heating rate while it increased when oxygen content in an atmosphere increased. Anthracite coal replacement with coke up to 100 pct promoted a decrease in the formed NOx amount and XNO by 21 and 53 pct, respectively. The addition of CaO and FeO enhanced the conversion of nitrogen to NOx, especially at temperatures below 1273 K (1000 °C). Taking both the oxidation reaction to form NOx and reduction reaction of NOx to form N2 into account, the activation energy (EA) values of anthracite and coke were evaluated to be 2.2 and 3.6 kJ/mol, respectively. The combustion of semi-anthracite coal emitted the largest amount of NOx, but the anthracite coal containing less fuel-N than other coals showed the highest value of XNO, which indicates that nitrogen content in coal is not the major factor affecting the formation of NOx. The change in nitrogen functionality after combustion process might be the reason for the unpredicted results in the XNO. The pyrrolic-N in anthracite coal might be considered to be the major functional form that directly affects the conversion of nitrogen to NO.

This article proposes REACT, a regular expression matching accelerator, which can be embedded in a modern Solid-State Drive (SSD) and a novel data access scheduling algorithm for high matching throughput. Specifically, REACT, including our data access scheduling algorithm, increases the utilization of SSD and the degree of internal memory parallelism for pattern matching processes. While the low-level flash exhibits long latency, modern SSDs in practice achieve high I/O performance by utilizing the massive internal parallelism at the system-level. However, exploiting the parallelism is limited for pattern matching since the sub-blocks, which constitute an input data and can be placed in multiple flash pages, should be tested in a sequence to process the input correctly. This limitation can induce low utilization of the accelerator. To address this challenge, the proposed REACT simultaneously processes multiple input streams with a parallel processing architecture to maximize matching throughput by hiding the long and irregular latency. The scheduling algorithm finds a data stream which requires a sub-block in closest time and prioritizes the access request to reduce the data stall of REACT. REACT achieves maximum 22.6 percent of matching throughput improvement on a 16-channel high-performance SSD compared to the accelerator without the proposed scheduling algorithm.

We demonstrate a superluminescent diode fabricated on a nonpolar ${m}$ -plane GaN substrate by employing a linearly tapered waveguide design. A high electrical −3dB modulation bandwidth ( $f_{\mathbf {3dB}}$ ) of 2.5 GHz at a current density of 30 kA/cm2 is achieved. The high modulation bandwidth is attributed to the shorter carrier recombination lifetime, the linear gain curve in the nonpolar ${m}$ -plane quantum wells, and the ability to operate at high current densities while effectively suppressing lasing. We derive a general expression for the −3dB bandwidth as a function of current density for SLDs using a similar approach to that for laser diodes. The −3dB bandwidth of a nonpolar superluminescent diode increases exponentially with current density. The experimental results are consistent with the derived expression for $f_{\mathbf {3dB}}$ vs . current density.

Various methods of wireless torque transfer have been introduced to the fields of applications and highly utilized. In this paper, a method of wirelessly transmitting torque to a magnetic material by generating a rotating magnetic field using multi-coils is proposed. The rotating magnetic field generated by the current flowing in the proposed coil arrangement can be proved by using Biot-Savart law. Therefore, when a magnetic material is placed between the proposed coils, torque is generated due to the rotating magnetic field. Furthermore, since the torque by the magnetic field is closely related to the current applied to the coils, so that the torque can be changed through current. The proposed method was verified through theoretical analysis and simulation.

Wireless Power Transfer (WPT) system are used in many areas due to their advantages such as safety, aesthetics, and convenience. The WPT system are being applied not only smartphones that are common around us, but also to various electronics and medical devices. In particular, in the case of Electric Vehicle (EV), researches are steadily underway to apply the WPT system to solve the problem of battery dependence. Inductive power transfer (IPT) is the most popular WPT method to transfer power using the magnetic field. However, Foreign Object (FO) in WPT system can be heated by strong magnetic field and can lead to fires. Also, it can reduce power transfer efficiency. The risk of fire in a WPT system such as EVs, which require large power, is a major obstacle. Therefore, FO detection method is necessary for the safety and good performance. In this paper, we propose a Foreign Object Detection method using sensor coils. The proposed method is simple and shows the good performance compared with conventional method.

In wireless power transfer system, a leakage electromagnetic field (EMF) that can affect a human body or peripheral devices is one of the most important problems along with system efficiency. Since ferrite and aluminum which are basically used to reduce the EMF have a high weight and cost, various studies to cancel the EMF using reverse magnetic field by additional coil are being conducted. In this paper, a reactive shield coil that can be applied to a wireless charger with multiple transmitter coils is proposed. The EMF is reduced by applying the proposed coil up to 85%.

The quest to improve the performance of organic light-emitting diodes (OLEDs) has led to the exploration of new materials with properties like interfacial dipole, excitons generation, and bandgap alignment. Here, we exploit these strategies by investigating the interaction of the antibiotic ampicillin with a widely used optoelectronic material, to fabricate state-of-the-art OLEDs. The charge distribution on the ampicillin molecule facilitates the generation of an interfacial dipole with a large magnitude. The optimum fusion of the two materials provides an enhanced bandgap alignment, charge balance and J/H-aggregated excitons. Values of current efficiency (120 cdA−1), external quantum efficiency (~35%) and power efficiency (70 lmW−1) are demonstrated. The cross-evaluation of performance with penicillin devices indicates the significance of ampicillin’s specific molecular structure in improving performance. The detailed investigations demonstrate that ampicillin has superior optoelectronic properties with high potential to contribute extensively in OLEDs and photovoltaics. The need to move away from silicon-based semiconductors for the electronic industry has yielded significant developments in the use of organic materials for devices. The authors present a method to enhance organic light-emitting diodes (OLEDs) performance by adding a common antibiotic, ampicillin into a common organic semiconductor and achieving a maximum external quantum efficiency of 35%.

High harmonic generation of ultrafast laser pulses can be used to perform angle-resolved photoemission spectroscopy (ARPES) to map the electronic band structure of materials with femtosecond time resolution. However, currently it is difficult to reach high momenta with narrow energy resolution. Here, we combine a gas phase extreme ultraviolet (XUV) femtosecond light source, an XUV monochromator, and a time-of-flight electron analyzer to develop XUV-based time-resolved ARPES. Our technique can produce tunable photon energy between 24–33 eV with an unprecedented energy resolution of 30 meV and time resolution of 200 fs. This technique enables time-, energy- and momentum-resolved investigation of the nonequilibrium dynamics of electrons in materials with a full access to their first Brillouin zone. We evaluate the performance of this setup through exemplary measurements on various quantum materials, including WTe2, WSe2, TiSe2, and Bi2Sr2CaCu2O8+δ., Currently, it is difficult to reach high momenta with narrow energy resolution via laser-based angle-resolved photoemission spectroscopy (ARPES). Here, Sie et al. develop a time-resolved XUV based ARPES setup which can access the first Brillouin zone of all materials with narrow energy resolution.

Joints properties of high temperature thermoelectric (TE) modules, which are composed of n-type Mg2Si and p-type higher manganese silicide (HMS), were investigated using the laser brazing process. In this process, the direct-bonded copper (DBC) and the TE materials were bonded using the Ag Cu based brazing filler metal. Heating and cooling rates were controlled by changing laser power and irradiation time gradually for preventing from thermal shock damage. The properties of joints were investigated by die shear test and microstructural analysis. As a result, improved joints of TE modules were fabricated through the laser brazing. Suitable heat input condition was deducted to optimize inter-diffusion between the filler metal and TE materials for obtaining reliable bond strength. In order to evaluate the high temperature stability, heat treatments were performed with TE modules using the furnace. As the heat treatment time increased, voids was formed at the joint but the diffusion distance of Cu and Ag did not increase.

For the fabrication of high-performance top-gated MoS2 transistors, a uniform atomic layer deposition (ALD) of an ultrathin high-k gate dielectric film without abnormal leakage paths on a MoS2 channel is required. In this study, we fabricated a ~5.2 nm-thick monolithic HfO2 gate dielectric film by utilizing an e-beam-evaporated Hf seed layer (target thickness of 3 nm) prior to the ALD of a HfO2 film (~2 nm). The Hf seed layer was fully converted to HfO2 without metallic residues during the following ALD process, without damages to the Raman and photoluminescence characteristics of the underlying MoS2. The conformal and pinhole-free ALD of the subsequent HfO2 film was verified using conductive atomic force microscopy. In addition, operation of a top-gated MoS2 transistor was demonstrated by integrating the Hf-seeded HfO2 gate dielectric film.

Defects in HfO2 dielectric film caused by indium and arsenide diffusion from InAs were investigated. To investigate the dissociation of InAs during post-deposition annealing (PDA) at 600 °C, we analyzed the ratio of the elements on the surface of the oxide layer and the chemical states by using time-of-flight secondary-ion mass spectroscopy and X-ray photoelectron spectroscopy, respectively. In–As bonding was dissociated and In and As atoms were diffused through the HfO2 layer from InAs. Fortunately, the diffusion and trap density could be controlled by using a 1-nm-thick Al2O3 passivation layer. In addition, we used the nitridation process to control the trap density. We evaluated the thermal and electrical stability of three samples—HfO2/InAs, HfO2/Al2O3/InAs, and nitrided HfO2/Al2O3/InAs—by analyzing the change in trap density before and after PDA at 600 °C and the stress-induced leakage current. In conclusion, the passivation layer effectively improved the thermal and electrical stability, whereas the nitridation process using NH3 gas did not. Moreover, although nitridation could reduce the interfacial defect states, due to structure distortion, it induced the degradation of the device.

Metal nanostructure arrays have been progressed as an alternative to the conventional oxides-based transparent conductive electrodes. Herein, we demonstrate the improved reliability of silver nanowire (AgNW) electrodes by photoresist encapsulation. The incorporation of photoresist followed by photolithography is beneficial to selectively pattern the AgNWs on poly[ether sulfone]. By varying the development or removal time of the ultraviolet (UV)-exposed photoresist, the properties of the AgNWs in the electrode are significantly varied. The optical parameters such as transmittance, haziness, and the yellow index of the electrodes have been extensively studied to reveal the advantage of the selective photoresist patterning. The AgNW electrodes patterned under 120 s of development time explored superior optical and electrical properties with high durability. The electrical properties of the AgNW electrodes at high temperatures (250 °C) demonstrate the photoresist-induced stability as compared to bare samples. Further, the morphological examination after the high temperature treatment reveals the reduced Rayleigh instability effects in 120 s developed AgNWs that facilitate the reliability under harsh conditions.

OBJECTIVE: To investigate the effects of the robot–assisted gait training on cortical activation and functional outcomes in stroke patients. METHODS: The patients were randomly assigned: training with Morning Walk® (Morning Walk group; n = 30); conventional physiotherapy (control group; n = 30). Rehabilitation was performed five times a week for 3 weeks. The primary outcome was the cortical activation in the Morning Walk group. The secondary outcomes included gait speed, 10-Meter Walk Test (10MWT), FAC, Motricity Index–Lower (MI–Lower), Modified Barthel Index (MBI), Rivermead Mobility Index (RMI), and Berg Balance Scale (BBS). RESULTS: Thirty-six subjects were analyzed, 18 in the Morning Walk group and 18 in the control group. The cortical activation was lower in affected hemisphere than unaffected hemisphere at the beginning of robot rehabilitation. After training, the affected hemisphere achieved a higher increase in cortical activation than the unaffected hemisphere. Consequently, the cortical activation in affected hemisphere was significantly higher than that in unaffected hemisphere (P = 0.036). FAC, MBI, BBS, and RMI scores significantly improved in both groups. The Morning Walk group had significantly greater improvements than the control group in 10MWT (P = 0.017), gait speed (P = 0.043), BBS (P = 0.010), and MI–Lower (P = 0.047) scores. CONCLUSION: Robot-assisted gait training not only improved functional outcomes but also increased cortical activation in stroke patients.

In roll-to-roll digital maskless lithography (R2R DML) equipment, it is difficult to achieve high quality, owing to surface deformation that affects the pattern position. To address this issue, we simulated the patterning results of R2R DML to analyze the relationship between positional errors and pattern quality. Errors perpendicular to the pattern direction exhibited a 1.3–2 times greater effect on the linewidth and line edge roughness compared to those parallel to this direction. We confirmed that positioning errors could lead to defects in which the photoresists were not fully exposed. Finally, through simulations, we found that the effect of positional errors could be reduced by controlling the array spot separation length.

A fluidic assembly of III-nitride micro-light-emitting diodes (μLEDs) is demonstrated by applying external forces. This work introduces a solution-based mass transfer approach for inorganic semiconductor devices with the advantages in being material- and dimensional-agnostic. This method offers precise control in device alignment and orientation. The alignment of μLEDs in solution is controlled by acoustic focusing and the induced pressure forces, and the device orientation is modulated using magnetic field. The detailed mechanisms of the use of acoustic focusing and magnetic field are discussed. This fluidic assembly technique allows high throughput rate and roll-to-roll manufacturing, which is critical to the mass transfer of μLEDs for display and functional fabric applications.

We demonstrate a high-speed LiFi (Light Fidelity) communication system deploying ultra-high brightness laser-based white light illumination sources in a surface mount device (SMD) package platform. The multi functionality sources provide 1000 lm of white light output with a brightness of 1000 cd/mm2 and data transmission rates beyond 20 Gbit/s from dual blue laser integrated SMD, and 500 lm of white light output with a brightness of 1000 cd/mm2 and data transmission rates beyond 25 Gbit/s from dual color of blue and infrared (IR) laser integrated SMD.

The Internet of Bio-nano Things is a significant development for next generation communication technologies. Because conventional wireless communication technologies face challenges in realizing new applications (e.g., in-body area networks for health monitoring) and necessitate the substitution of information carriers, researchers have shifted their interest to molecular communications (MC). Although remarkable progress has been made in this field over the last decade, advances have been far from acceptable for the achievement of its application objectives. A crucial problem of MC is the low data rate and high error rate inherent in particle dynamics specifications, in contrast to wave-based conventional communications. Therefore, it is important to investigate the resources by which MC can obtain additional information paths and provide strategies to exploit these resources. This study aims to examine techniques involving resource aggregation and exploitation to provide prospective directions for future progress in MC. In particular, we focus on state-of-the-art studies on multiple-input multiple-output (MIMO) systems. We discuss the possible advantages of applying MIMO to various MC system models. Furthermore, we survey various studies that aimed to achieve MIMO gains for the respective models, from theoretical background to prototypes. Finally, we conclude this study by summarizing the challenges that need to be addressed., Comment: 7 pages, 4 figures, accepted in Communications Magazine

This study prognoses the remaining useful life of a turbofan engine using a deep learning model, which is essential for the health management of an engine. The proposed deep learning model affords a significantly improved accuracy by organizing networks with a one-dimensional convolutional neural network, long short-term memory, and bidirectional long short-term memory. In particular, this paper investigates two practical and crucial issues in applying the deep learning model for system prognosis. The first is the requirement of numerous sensors for different components, i.e., the curse of dimensionality. Second, the deep neural network cannot identify the problematic component of the turbofan engine due to its &ldquo, black box&rdquo, property. This study thus employs dimensionality reduction and Shapley additive explanation (SHAP) techniques. Dimensionality reduction in the model reduces the complexity and prevents overfitting, while maintaining high accuracy. SHAP analyzes and visualizes the black box to identify the sensors. The experimental results demonstrate the high accuracy and efficiency of the proposed model with dimensionality reduction and show that SHAP enhances the explainability in a conventional deep learning model for system prognosis.

Stretchable organic light-emitting diodes are ubiquitous in the rapidly developing wearable display technology. However, low efficiency and poor mechanical stability inhibit their commercial applications owing to the restrictions generated by strain. Here, we demonstrate the exceptional performance of a transparent (molybdenum-trioxide/gold/molybdenum-trioxide) electrode for buckled, twistable, and geometrically stretchable organic light-emitting diodes under 2-dimensional random area strain with invariant color coordinates. The devices are fabricated on a thin optical-adhesive/elastomer with a small mechanical bending strain and water-proofed by optical-adhesive encapsulation in a sandwiched structure. The heat dissipation mechanism of the thin optical-adhesive substrate, thin elastomer-based devices or silicon dioxide nanoparticles reduces triplet-triplet annihilation, providing consistent performance at high exciton density, compared with thick elastomer and a glass substrate. The performance is enhanced by the nanoparticles in the optical-adhesive for light out-coupling and improved heat dissipation. A high current efficiency of ~82.4 cd/A and an external quantum efficiency of ~22.3% are achieved with minimum efficiency roll-off., A transparent twistable and stretchable MoO3/Au/MoO3 electrode is demonstrated by Choi et al. for organic light-emitting diodes. The device fabricated on thin elastomer shows enhanced EQE with minimum efficiency roll-off owing to the improved charge injection and heat dissipation from the substrate.

This paper proposes a deep-stacked neural network to prognose the remaining useful life of the turbofan engines and analyze results using explainable artificial intelligence. The proposed model prognoses the remaining useful life of the turbofan engines accurately by properly stacking a one-dimensional convolutional neural network (1D-CNN), long short-term memory (LSTM), and bidirectional LSTM algorithms. This model also uses dropout technique and residual network to enhance the prediction accuracy. The Explainable artificial intelligence analyzes the prognostic results of RUL. Using SHAP (SHapely Addictive exPlanation), this model can analyze features that have significantly influenced RUL prediction. The SHAP force plot and decision plot can help decision-makers of the turbofan engine properly manage the maintenance by showing the influence of sensors.

In this paper, we perform the simulation of arbitrary pattern to be recorded using the point array technique. At first, it is assumed that lithography is performed by forming an array spot based on a DMD device that is turned at a specific angle. The simulation was constructed in two steps: creating images for DMD and predicting pattern results. In the simulation process, we reflect the parameter of the each spot in point array. The parameters are consist of spot position, spot size, and spot intensity profile.

This Conference Presentation, "Characterization of position and two-dimensional profiles of high-density beam spot array for digital lithography system," was recorded for SPIE Optics + Photonics Digital Forum 2020.

We reported significant improvements in device speed by reducing the quantum barrier (QB) thicknesses in the InGaN/GaN multiple quantum well (MQW) photodetectors (PDs). A 3-dB bandwidth of 700 MHz was achieved with a reverse bias of -6 V. Carrier escape lifetimes due to carrier trapping in the quantum wells (QWs) were obtained from both simulation and experimental fitting, identifying carrier trapping as the major speed limiting factor in the InGaN/GaN MQW PDs.

Consideration of livestock farming practices is necessary for the reliable prediction of veterinary antibiotics concentrations in livestock manure and soil and characterization of their ecological risks. This study aims to predict concentrations of chlortetracycline (CTC) generated from slurry pit and evaluate its ecological risk in soil based on the European Medicine Agency guidelines by considering slurry pit farm practices such as cleaning water volume and those uncertainties. Additionally, sensitivity analysis was conducted on the exposure estimation of CTC in soil employing the Monte Carlo simulation. The predicted environmental concentrations of CTC in the slurry pit and soil were in a range of 0.54–5.64 mg/kgmanure and 3.42–67.59 μg/kgsoil, respectively, for a 90 % confidence level. The predicted ranges included the measured values reported in previous studies. The probability of risk quotient (RQ) exceeding one was estimated at 9.3 % based on the Monte Carlo simulation. The four most influential factors on the exposure to CTC in soil were identified as nitrogen in fertilizer/compost, cleaning water volume, ratio of sick pigs requiring antibiotics, and pit emptying cycles. The results indicate that the ecological risk of CTC in the soil is possible and can be controlled by slurry pit farm practices.

Sol-gel-processed Mg-doped SnO2 thin-film transistors (TFTs) were successfully fabricated. The effect of Mg concentration on the structural, chemical, and optical properties of thin films and the corresponding TFT devices was investigated. The results indicated that an optimal Mg concentration yielded an improved negative bias stability and increased optical band gap, resulting in transparent devices. Furthermore, the optimal device performance was obtained with 0.5 wt% Mg. The fabricated 0.5 wt% Mg-doped SnO2 TFT was characterized by a field effect mobility, a subthreshold swing, and Ion/Ioff ratio of 4.23 cm2/Vs, 1.37 V/decade, and ~1 &times, 107, respectively. The added Mg suppressed oxygen-vacancy formation, thereby improving the bias stability. This work may pave the way for the development of alkaline-earth-metal-doped SnO2-based thin-film devices.

We demonstrate high-speed LiFi data communication of over 20 Gbit/s using visible light from a laser-based white light emitting surface mount device (SMD) product platform that offers 10-100X the brightness of conventional LED sources. Equipped with high power blue laser diodes that offer over 3.5 GHz of 3 dB bandwidth, the laser-based white light SMD modules exhibited a signal-to-noise ratio (SNR) above 15 dB up to 1 GHz. The high SNR was combined with high order quadrature amplitude modulation (QAM) and orthogonal frequency division multiplexing (OFDM) to maximize the bandwidth efficiency. In this work, we present a laser based white light SMD module configured with a single 3W blue laser diode mounted on heat-sink, optically coupled to a collimating optic, achieving a LiFi data rate of up to 10 Gbit/s. Moreover, we demonstrate wavelength division multiplexing (WDM), from a white light SMD module configured with two blue laser diodes separated in peak wavelength to serve as separate communication channels. Using WDM, the dual laser SMD module enabled LiFi data rates of over 20 Gbit/s by simultaneously transmitting data over both channels.

Currently, there are two representative non-volatile dual in-line memory module (NVDIMM) interfaces: a proprietary Intel DDR-T and the JEDEC NVDIMM-P, which are not supported by existing platforms. Adoption of new platform is costly and measuring its efficiency of migrating to the new platform is much more complex. This study is an alternative way of them—finding a new memory device that can be supported by all existing systems. In this paper, we propose an NVDIMM architecture with several system-wide mechanisms to allow the synchronous DDR4 memory interfaces to support non-deterministic (asynchronous) timing. The proposed memory architecture is implemented as a real device prototype, and also evaluated using synthetic and real workloads on an x86-64 server system.

We report on wavelength-selective semipolar ( 20 21 ¯ ) InGaN/GaN micro-photodetector with broad modulation bandwidth of 293.52 MHz, outperforming polar-based devices. A 1.5-Gbit/s data rate was achieved without the need of spectral-efficient modulation format.

This paper proposes a microarchitectural mechanism to minimize the latency of thread migration for a tightly-coupled heterogeneous core, which has two execution backends (e.g., in-order and out-of-order execution pipelines). The proposed mechanism examines the dependencies between all in-flight instructions that reside in one of the backend pipelines, and allows both pipelines to simultaneously perform the instruction execution. At the microarchitectural level, instruction dispatching and instruction execution are seamlessly performed across thread migration, and therefore, this simultaneous backend execution can accelerate the program execution, which cannot be achieved with an existing migration mechanism. Accelerating thread migration will increase the overall performance with low power overhead, providing high energy efficiency. As compared to a baseline heterogeneous core with an existing migration mechanism, the simultaneous backend execution reduces 8.2 percent of the total execution cycle and consumes 2.9 percent lower total energy on average across SPEC CPU2006 benchmarks, which results in an improved energy efficiency of 10.9 percent in terms of the energy-delay product.

For local homing navigation, a mobile robot is supposed to return home using snapshots of the surrounding environment. It basically follows the snapshot model, comparing the home snapshot and the current view to determine the homing direction. In this paper, we suggest a high-order moment potential to describe the landmark feature distribution for local homing navigation. The moment potential function calculates the sum of products of the feature and the distance of landmark particles as a holistic view, allowing a high order of the distance. It effectively combines the range sensor values of landmarks in the current view and the visual features. By analogy with the moment in physics, the center of the moment is estimated as the reference point, which is the unique convergence point in the convex moment potential from any view, and using the property, the gradient of moment potential at the current position and home location can derive the homing vector. We provide a proof of convergence for any moment potential with order greater than or equal to one. Also, we demonstrate homing performances with various moment models in real environments to validate our models. The suggested moment models combining both landmark distance and visual feature have better performances than the visual information alone, and high-order moment potentials can be searched to obtain a better description of landmark distribution for a given environment.

Visual homing navigation has been a challenging issue in indoor localization and navigation. Inspired by insect navigation, the snapshot model was introduced for homing navigation, where a pair of snapshots at the current location and at the nest are compared to guide the homing direction. We investigate Haar-like features in vision to extract visual cues, based on the snapshot model. The Haar-like features consist of masks randomly generated over the snapshot image at the home location, and later, their matching scores at the snapshot available at the current location are calculated for the correspondence measure. We draw landmark vectors using the correspondence measure of Haar-like features at their angular positions. Interestingly, a collection of Haar-like features provide visual characteristics to reflect a pair of snapshot images, which can determine the homing direction. In this paper, we propose two types of homing methods based on the image difference using Haar-like features, the Haar-like landmark vector model and the Haar-like image distance model. We demonstrate the effectiveness of the methods in several environments.

Indistinguishability Obfuscation ( $iO$ ) is a hopeful tool which obfuscates a program with the least-possible leakage, and produces various applications including functional encryption and deniable encryption. Recently, Halevi et. al. proposed a state-of-the-art obfuscator implementation, called HHSS obfuscation, in ACM-CCS’17. In this paper, we describe a polynomial time distinguishing attack on HHSS obfuscation. In other words, we show that there exist two functionally equivalent branching programs but obfuscated programs are actually distinguishable. This attack implies that HHSS obfuscation fails to achieve a general purpose of $iO$ security. The idea of the attack is quite simple; we multiply a left kernel vector of the branching program ${\mathcal P}$ to an evaluation of obfuscated matrix, which yields a small value when the program ${\mathcal P}$ is obfuscated. Our attack algorithm is also applicable even if evasive functions are obfuscated.

This paper reports the variation in the optical and geometrical properties of individual organic layers to be used for thermally damaged top-emission organic light-emitting diodes (TEOLEDs). The copper deposited on the back of TEOLEDs is employed as a thermal facilitator, and a certain thermal damage occurs to the organic layers and devices. The phosphorescent host material 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) is rapidly damaged to a significant extent owing to the low glass transition temperature (Tg), which also changes its optical and geometrical surface properties. Although the optical properties of the hole transport layer, N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) were changed slightly, the surface morphology was changed significantly. Despite having a higher Tg, the exciton blocking layer, tris(4-carbazoyl-9-ylphenyl)amine (TCTA), shows notable variations in optical properties and surface morphology due to heat exposure. Surprisingly, the electroluminescence spectra and micro-cavity are affected by increasing temperature without any considerable changes in device performance. Hence, this study reveals that besides Tg, the surface morphologies and thicknesses of the organic layers are also important factors in the annealing process and play a vital role in causing thermal damage to TEOLEDs.

The optical and electrical characteristics of InGaN blue and green micro-light-emitting diodes (μLEDs) with GaN tunnel junction (TJ) contacts grown by metalorganic chemical vapor deposition (MOCVD) were compared at different activation temperatures among three activation methods from the literature, namely, sidewall activation, selective area growth (SAG), and chemical treatment before sidewall activation. The devices with chemical treatment before activation resulted in uniform electroluminescence and higher light output power, compared to the devices with sidewall activation and SAG. Moreover, the green μLEDs showed greater optical degradation at elevated activation temperatures, whereas the blue μLEDs yielded trivial difference with activation temperatures from 670 to 790 °C. The 5 × 5 μm2 devices with chemical treatment before activation and SAG yielded almost identical voltage at 20 A/cm2, and the voltage penalty significantly decreased with activation temperature in the case of devices with sidewall activation. The devices with chemical treatment before activation resulted in higher external quantum efficiency (EQE) and wall-plug efficiency (WPE) in low current density range compared to the devices with SAG. The enhancements in EQE and WPE were observed in different μLED sizes, suggesting that chemical treatment before sidewall activation enables the use of TJ contacts grown by MOCVD and is advantageous for applications that require high brightness and efficiency.