Showing papers by "University of Electro-Communications published in 2022"
TL;DR: In this article , a physical zero-knowledge proof (ZKP) protocol for Suguru was proposed, which allows a prover to prove that he knows a solution of a Suguru grid to a verifier without leaking any information on the solution.
Abstract: Suguru is a paper and pencil puzzle invented by Naoki Inaba. The goal of the game is to fill a grid with numbers between 1 and 5 while respecting three simple constraints. We first prove the NP-completeness of Suguru puzzle. For this we design gadgets to encode the PLANAR-CIRCUIT-SAT in a Suguru grid. We then design a physical Zero-Knowledge Proof (ZKP) protocol for Suguru. This ZKP protocol allows a prover to prove that he knows a solution of a Suguru grid to a verifier without leaking any information on the solution. To construct such a physical ZKP protocol, we only rely on a few physical cards and adapted encoding. For a Suguru grid with n cells, we only use 5n+5 cards. Moreover, we prove the three classical security properties of a ZKP: completeness, extractability, and zero-knowledge.
14 citations
TL;DR: In this paper , a combination of luminescence processes in dual-emission properties by selecting preparation protocols is designed but also temperature-driven switching of luminariescence processes based on a bis- o -carborane-substituted anthracene triad in crystals.
Abstract: A combination of luminescence processes in dual-emission properties by selecting preparation protocols is designed but also temperature-driven switching of luminescence processes in dual-emission properties based on a bis- o -carborane-substituted anthracene triad in crystals.
12 citations
TL;DR: In this article , the authors synthesized elemental skeletons composed of robust π-conjugated systems including two boron-fused azo groups, which showed an intense emission in the red or near-infrared (NIR) region both in solution and solid states.
Abstract: Development of novel near-infrared (NIR) emitters is essential for satisfying the growing demands of advancing optical telecommunication and medical technology. We synthesized elemental skeletons composed of robust π-conjugated systems including two boron-fused azo groups, which showed an intense emission in the red or near-infrared (NIR) region both in solution and solid states. Two types of bisboron complexes with different aromatic linkers showed emission properties with larger bathochromic shifts and emission efficiencies in solution than the corresponding monoboron complex. Transient absorption spectroscopy disclosed that the inferior optical properties of the monoboron complex can be attributed to fast nonradiative deactivation accompanied by a large structural relaxation after photoexcitation. The expanded π-conjugated system through multiple boron-fused azo groups can contribute to rigid molecular skeletons followed by improved emission properties. Moreover, the anti-form of the bisboron complex with fluorine groups in the opposite directions to the π-plane exhibited crystallization-induced emission enhancement in the NIR region. The molecular design by using multiple boron-fused azo groups is expected to be a critical strategy for creating novel NIR emitters.
11 citations
TL;DR: A card-based protocol of zero-knowledge proof (ZKP) for Sudoku was proposed in this paper , which can be performed using only two standard decks of playing cards, regardless of whether the two decks are identical or different.
Abstract: Sudoku is a famous logic puzzle where the player has to fill a number between 1 and 9 into each empty cell of a $$9 \times 9$$ grid such that every number appears exactly once in each row, each column, and each $$3 \times 3$$ block. In 2020, Sasaki et al., developed a physical card-based protocol of zero-knowledge proof (ZKP) for Sudoku, which enables a prover to convince a verifier that he/she knows a solution of the puzzle without revealing it. Their protocol uses 90 cards, but requires nine identical copies of some cards, which cannot be found in a standard deck of playing cards (consisting of 52 different cards and two jokers). Hence, nine identical standard decks are required to perform that protocol, making the protocol not very practical. In this paper, we propose a new ZKP protocol for Sudoku that can be performed using only two standard decks of playing cards, regardless of whether the two decks are identical or different. In general, we also develop the first ZKP protocol for a generalized $$n \times n$$ Sudoku that can be performed using a deck of all different cards.
10 citations
TL;DR: In this article , a rational design for triplet sensitizers was proposed to enable high-efficiency red afterglow RT emission at wavelengths exceeding 600 nm, where the long conjugated amino-substituent hardly enhanced the fluorescence resonance energy transfer from the sensitizer to the acceptor.
Abstract: An efficient and bright red afterglow emission with a lifetime of more than 100 ms is essential for the detection of emission signals independent of autofluorescence from targets in deep locations under in vivo conditions. However, the afterglow room-temperature (RT) emission yield at wavelengths over 600 nm is less than 5.5%. Here, we report a rational design for triplet sensitizers to enable high-efficiency red afterglow RT emission. Two triphenylene derivatives with amino-conjugated substituents were synthesized in the form of triplet sensitizers to induce red afterglow RT emission from a fluorescent acceptor. The material that contained the sensitizer with the longer conjugated substituent and the acceptor produced red afterglow RT emission with a yield of 8.5% for wavelengths exceeding 600 nm. The long conjugated amino-substituent hardly enhanced the fluorescence resonance energy transfer from the sensitizer to the acceptor, causing the red afterglow RT emission yield to decrease. However, the long conjugated substituent greatly enhanced the phosphorescence resonance energy transfer (PRET) from the sensitizer to the acceptor. A large increase in the transition dipole moment between the high-order singlet excited states and the ground state was caused by the long conjugated amino-substituent and was a key factor in enabling the sensitizer to produce selective large-scale enhancement of the PRET for enhanced red afterglow RT emission.
9 citations
TL;DR: In this paper , the authors investigated whether the human brain can own an independent supernumerary limb and found that ownership does seem possible, as they observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership.
Abstract: Can our brain perceive a sense of ownership towards an independent supernumerary limb; one that can be moved independently of any other limb and provides its own independent movement feedback? Following the rubber-hand illusion experiment, a plethora of studies have shown that the human representation of "self" is very plastic. But previous studies have almost exclusively investigated ownership towards "substitute" artificial limbs, which are controlled by the movements of a real limb and/or limbs from which non-visual sensory feedback is provided on an existing limb. Here, to investigate whether the human brain can own an independent artificial limb, we first developed a novel independent robotic "sixth finger." We allowed participants to train using the finger and examined whether it induced changes in the body representation using behavioral as well as cognitive measures. Our results suggest that unlike a substitute artificial limb (like in the rubber hand experiment), it is more difficult for humans to perceive a sense of ownership towards an independent limb. However, ownership does seem possible, as we observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership. Our results provide the first evidence to show that an independent supernumerary limb can be embodied by humans.
9 citations
TL;DR: In this paper, an integrated approach based on the analytical and reverse order methods is proposed to obtain the closed-form solution of the robotic arm at the position level, where the coordinate system establishment method and mapping relationship of the Denavit-Hartenberg (D-H) parameters at positive and reverse-order robotic arms are deduced.
9 citations
TL;DR: In this paper , the authors observed the 70 μ m dark infrared dark cloud (IRDC) G14.492-00.139 with the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the ALMA Survey of 70 µ m Dark High-mass Clumps in Early Stages.
Abstract: Abstract We have observed the 70 μ m dark infrared dark cloud (IRDC) G14.492-00.139 in the N 2 D + J = 3–2, DCO + J = 3–2, DCN J = 3–2, and C 18 O J = 2–1 lines, using the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the ALMA Survey of 70 μ m Dark High-mass Clumps in Early Stages. We find that the spatial distribution is different among the observed emission from the deuterated molecular lines. The N 2 D + emission traces relatively quiescent regions, while both the DCO + and DCN emission emanate mainly from regions with signs of active star formation. In addition, the DCO + /N 2 D + ratio is found to be lower in several dense cores than in starless cores embedded in low-mass star-forming regions. By comparing the observational results with chemical-model calculations, we discuss the origin of the low DCO + /N 2 D + ratio in this IRDC clump. The low DCO + /N 2 D + ratio can be explained if the temperature of the dense cores is in the range between the sublimation temperatures of N 2 (∼20 K) and CO (∼25 K). The results suggest that the dense cores in G14.492-00.139 are warmer and denser than the dense cores in low-mass star-forming regions.
8 citations
TL;DR: In this article , an integrated neuromechanical model of movement based on physical measurements by taking Drosophila larvae as a model of soft-bodied animals is proposed, and the model predicts that peristaltic locomotion could be exhibited in a low-friction condition.
Abstract: Animal locomotion requires dynamic interactions between neural circuits, the body (typically muscles), and surrounding environments. While the neural circuitry of movement has been intensively studied, how these outputs are integrated with body mechanics (neuromechanics) is less clear, in part due to the lack of understanding of the biomechanical properties of animal bodies. Here, we propose an integrated neuromechanical model of movement based on physical measurements by taking Drosophila larvae as a model of soft-bodied animals.We first characterized the kinematics of forward crawling in Drosophila larvae at a segmental and whole-body level. We then characterized the biomechanical parameters of fly larvae, namely the contraction forces generated by neural activity, and passive elastic and viscosity of the larval body using a stress-relaxation test. We established a mathematical neuromechanical model based on the physical measurements described above, obtaining seven kinematic values characterizing crawling locomotion. By optimizing the parameters in the neural circuit, our neuromechanical model succeeded in quantitatively reproducing the kinematics of larval locomotion that were obtained experimentally. This model could reproduce the observation of optogenetic studies reported previously. The model predicted that peristaltic locomotion could be exhibited in a low-friction condition. Analysis of floating larvae provided results consistent with this prediction. Furthermore, the model predicted a significant contribution of intersegmental connections in the central nervous system, which contrasts with a previous study. This hypothesis allowed us to make a testable prediction for the variability in intersegmental connection in sister species of the genus Drosophila.We generated a neurochemical model based on physical measurement to provide a new foundation to study locomotion in soft-bodied animals and soft robot engineering.
6 citations
TL;DR: In this paper , the authors developed an artificial intelligence that monitors the aurora appearance in Tromsø, Norway, instead of relying on the human eye, and implemented a web application that notifies the scientists of the appearance of auroras in real-time.
Abstract: The activity of citizen scientists who capture images of aurora borealis using digital cameras has recently been contributing to research regarding space physics by professional scientists. Auroral images captured using digital cameras not only fascinate us, but may also provide information about the energy of precipitating auroral electrons from space; this ability makes the use of digital cameras more meaningful. To support the application of digital cameras, we have developed artificial intelligence that monitors the auroral appearance in Tromsø, Norway, instead of relying on the human eye, and implemented a web application, "Tromsø AI", which notifies the scientists of the appearance of auroras in real-time. This "AI" has a double meaning: artificial intelligence and eyes (instead of human eyes). Utilizing the Tromsø AI, we also classified large-scale optical data to derive annual, monthly, and UT variations of the auroral occurrence rate for the first time. The derived occurrence characteristics are fairly consistent with the results obtained using the naked eye, and the evaluation using the validation data also showed a high F1 score of over 93%, indicating that the classifier has a performance comparable to that of the human eye classifying observed images.
5 citations
TL;DR: In 2018, Bultel et al. as mentioned in this paper proposed a physical zero-knowledge proof (ZKP) protocol for Makaro that can be implemented using a standard deck (a deck consisting of all different cards).
Abstract: Makaro is a logic puzzle with an objective to fill numbers into a rectangular grid to satisfy certain conditions. In 2018, Bultel et al. developed a physical zero-knowledge proof (ZKP) protocol for Makaro using a deck of cards, which allows a prover to physically convince a verifier that he/she knows a solution of the puzzle without revealing it. However, their protocol requires several identical copies of some cards, making it impractical as a deck of playing cards found in everyday life typically consists of all different cards. In this paper, we propose a new ZKP protocol for Makaro that can be implemented using a standard deck (a deck consisting of all different cards). Our protocol also uses asymptotically less cards than the protocol of Bultel et al. Most importantly, we develop a general method to encode a number with a sequence of all different cards. This allows us to securely compute several numerical functions using a standard deck, such as verifying that two given numbers are different and verifying that a number is the largest one among the given numbers.
TL;DR: In this article , the authors conducted a post hoc analysis of a Japanese phase 2/3 study of safinamide (50 or 100 mg/day) in patients with Parkinson's disease and wearing-off to evaluate response according to background factors.
TL;DR: In this paper , the authors argue that large reserve holdings have led central banks to approach their investment more systematically and to make rebalancing in the face of exchange rate changes the norm.
TL;DR: In this paper , the kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity, and a number of derivatives have arisen and have caused confusion.
Abstract: The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA , the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered ‘alignment outliers’ in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients’ own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients’ own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal.
TL;DR: In this article , a density functional theory approach was employed to predict the crystal structures of new honeycomb layered tellurates embodied by the composition, $A\rm_2 Ni_2TeO_6$ (A$ = alkali, hydrogen or coinage-metal cations).
TL;DR: The authors constructed a database containing several sets of material images annotated with visual discrimination performance and conducted psychophysical experiments with them in both laboratory and crowdsourcing settings, showing that the results obtained through crowdsourcing were highly correlated with those obtained in the laboratory.
Abstract: Complex visual processing involved in perceiving the object materials can be better elucidated by taking a variety of research approaches. Sharing stimulus and response data is an effective strategy to make the results of different studies directly comparable and can assist researchers with different backgrounds to jump into the field. Here, we constructed a database containing several sets of material images annotated with visual discrimination performance. We created the material images using physically based computer graphics techniques and conducted psychophysical experiments with them in both laboratory and crowdsourcing settings. The observer's task was to discriminate materials on one of six dimensions (gloss contrast, gloss distinctness of image, translucent vs. opaque, metal vs. plastic, metal vs. glass, and glossy vs. painted). The illumination consistency and object geometry were also varied. We used a nonverbal procedure (an oddity task) applicable for diverse use cases, such as cross-cultural, cross-species, clinical, or developmental studies. Results showed that the material discrimination depended on the illuminations and geometries and that the ability to discriminate the spatial consistency of specular highlights in glossiness perception showed larger individual differences than in other tasks. In addition, analysis of visual features showed that the parameters of higher order color texture statistics can partially, but not completely, explain task performance. The results obtained through crowdsourcing were highly correlated with those obtained in the laboratory, suggesting that our database can be used even when the experimental conditions are not strictly controlled in the laboratory. Several projects using our dataset are underway.
TL;DR: In this article , the authors reported atmospheric electric field (AEF) anomalies observed around the time of earthquakes (EQs) in Japan, which were likely caused by internal gravity waves (IGWs) generated around the EQ epicenter a few hours before the earthquakes, passing over the field site while changing the AEF by changing the space charge density.
Abstract: In this study, we report atmospheric electric field (AEF) anomalies observed around the time of earthquakes (EQs) in Japan. Using a newly developed AEF observation network with three spatially separated stations in Japan (Chofu, Kakioka, and Iwaki), we conducted a study for two EQs that occurred within a few 100 km from the EQ epicenter under relatively good local weather conditions as shown by a local all-sky camera and weather information. Time series and wavelet analyses of the AEF indicate that fluctuation anomalies in the AEF with periods of 10–60 min and larger than 70 min were observed from a few hours before up to a few hours after the occurrence of the EQs. The lag in the onset time increased with increasing distance from the EQ epicenter to the field site. The above-mentioned characteristics of these AEF fluctuation anomalies were similar among the three stations, and therefore the observed AEF anomalies were considered to be an imminent precursor of EQs. The observed AEF anomalies were likely to be caused by internal gravity waves (IGWs) generated around the EQ epicenter a few hours before the EQ, passing over the field site while changing the AEF by changing the space charge density in the surface layer of the atmosphere.
TL;DR: In this article , a multi-segment model is developed by considering the spatial-temporal characteristics of traffic flow, and detailed field measurements have been conducted in an urban tunnel with car accident during the evening rush hours in a winter day.
TL;DR: In this article, an s × s matrix Ks is constructed from the Hilbert matrix Hs and it is shown that Ks has at least one pair of complex eigenvalues when s ≥ 2.
Abstract: Abstract In this short note, we define an s × s matrix Ks constructed from the Hilbert matrix Hs=(1i+j-1)i,j=1s{H_s} = \\left( {{1 \\over {i + j - 1}}} \\right)_{i,j = 1}^s and prove that it has at least one pair of complex eigenvalues when s ≥ 2. Ks is a matrix related to the AVF collocation method, which is an energy-preserving/dissipative numerical method for ordinary differential equations, and our result gives a matrix-theoretical proof that the method does not have large-grain parallelism when its order is larger than or equal to 4.
TL;DR: In this article , the dual spaces of weighted Sobolev spaces and weighted homogeneous Besov spaces were determined by using the weighted Hausdorff capacity, and two embedding inequalities were established.
Abstract: In this paper, we establish two embedding inequalities for the weighted Sobolev space and the weighted homogeneous endpoint Besov space by using the weighted Hausdorff capacity. To do this, we shall determine the dual spaces of weighted Choquet and weighted homogeneous Besov spaces.
TL;DR: In this paper , a closed-form expression that can be applied to a small dipole antenna or a half-wavelength antenna is shown by using an equation applicable to spatial correlation in a three-dimensional multipath environment.
Abstract: A double integral operation is required to obtain gain in an array antenna in general, and only an omnidirectional antenna is represented in a closed form. In this letter, as a result of radio-wave propagation research, a closed-form expression that can be applied to a small dipole antenna or a half-wavelength dipole antenna is shown by using an equation applicable to spatial correlation in a three-dimensional multipath environment. In addition, the maximum gain characteristics of the half-wavelength dipole element linear array antenna are analyzed using the equation.
TL;DR: In this paper, it was shown that the time from the contact of primary drop with a liquid film is a crucial parameter in determining the size, ejection velocity, and ejection angle of secondary drops.
TL;DR: In this article , a hexagonal liquid crystal was built by assembling only one pair of short double-stranded DNA in buffer-salt solutions containing poly (ethylene glycol).
Abstract: Novel hexagonal liquid crystals were built by assembling only one pair of short double-stranded DNA in buffer-salt solutions containing poly (ethylene glycol). Complementary overhangs were required to construct the hexagonal DNA assemblies. Circular dichroism spectral measurements and polarization microscopy observations indicated a parallel alignment of double-stranded DNA in the hexagonal platelet.
TL;DR: The authors assesses motivations for the Fed liquidity lines, and the effects and spillovers of US dollar auctions by central banks using these lines, finding that access to Fed liquidity arrangements was driven by the recipient economies' close financial and trade ties with the US.
TL;DR: In this paper , the performance and sustainability of various active layer coating methods for organic solar cells (OSCs) were evaluated and the suitability of each coating method for industrial manufacturing of PCDTBT:PC71BM OSCs was discussed in terms of environmental impact, necessary investments and running costs.
TL;DR: In this article , a step-by-step fracture-mode classification method using fracture-surface images, from low to high magnification, based on the fractography knowledge of experts, is proposed.
Abstract: Fractography is a practical method of determining the cause of a mechanical-structure failure. Accurate decisions regarding fracture-mode classification require experience and knowledge, which may be difficult to share. Therefore, a database of fracture-surface images should be created, and the decision algorithm typically used by experts must be digitized. In recent years, although image classification using deep learning has been successful, it requires a large amount of data and is difficult to interpret. We propose a step-by-step fracture-mode classification method using fracture-surface images, from low to high magnification, based on the fractography knowledge of experts. Fracture-mode classification is performed using texture features for each patch image that is cut out from the fracture-surface image. The fracture mode for the fracture-surface image is voted based on the results of the patch-image classification. In the classification experiments of three fracture modes, the proposed method classifies the fracture mode in patch images with an accuracy of approximately 90%. Moreover, the classification results of the patch images are voted to correctly classify all fracture-surface images as their respective mode, even from a small dataset.
01 Jan 2022
01 Jan 2022
TL;DR: In this paper , the equivalence between the two types of informativity for the identification of partially observable systems is derived based on a newly introduced vector autoregressive with exogenous input (VARX) framework.
Abstract: This study shows that the informativity for the identification of partially observable systems is equivalent to that for designing dynamical measurement-feedback stabilizers. This finding is entirely different from the input-state case, where the direct data-driven design of state-feedback stabilizers requires less informativity than system identification. We derive the equivalence between the two types of informativity based on a newly introduced vector autoregressive with exogenous input (VARX) framework, which is suitable for time-domain analyses such as state-space models while directly representing input–output characteristics such as transfer functions. Moreover, we show a duality between the characterization of all VARX models explaining data and that of all VARX controllers stabilizing such VARX models.
01 Jan 2022
TL;DR: In this article , the authors introduce a new approach to considering the reliability and safety of real-world systems operating in diverse environments by introducing the concept of emergent failures caused by component interactions, along with a model that focuses on the gray zone (GZ) between normal and failure (or the GZ between safety and danger).
Abstract: Although reliability and safety engineering theories have previously been systematized as a related discipline, numerous accidents continue to occur in large-scale complex systems, primarily because those theories lack a system perspective. This chapter will introduce a new approach to considering the reliability and safety of real-world systems operating in diverse environments by introducing the concept of emergent failures caused by component interactions, along with a model that focuses on the gray zone (GZ) between normal and failure (or the GZ between safety and danger), which is not found in conventional theories based on two-valued logic.