Trajectory identification based on spatio-temporal proximity patterns between mobile phones

Growing popularity of location-dependent mobile applications is continuously stimulating a demand for localization technology. However, in spite of significant research effort in the past decade, precise positioning in indoor environments is still an open problem. In this paper, we propose a novel type of indoor localization system that provides mobile phone users in a pedestrian crowd with their own position information of sub-meter accuracy by effectively utilizing a powerful pedestrian tracking capability of laser range scanners (i.e., laser-based distance measurement sensors). Although the laser-based tracking system can precisely detect presence of pedestrians at each location in its sensing region, the location information is not associated with any mobile phone users and thus it basically cannot provide the users’ own locations. To remove this limitation, we focus on spatio-temporal proximity patterns between mobile phones, which can be detected by peer-to-peer short-range wireless communication (e.g., Bluetooth). By examining consistency between the communication logs and proximity between anonymous trajectories detected by laser-based tracking, our system identifies a trajectory that corresponds to each mobile phone user to offer their own position information. Through extensive simulations and field experiments, we show that our system can achieve trajectory identification accuracy of up to 91 %.     

Monolithic integration of Pb(Zr,Ti)O3 thin film based resonators using a complete dry microfabrication process

Monolithic fabrication of lead zirconate titanate [Pb(Zr,Ti)O₃ or PZT] based thin film resonant devices such as microcantilevers, Lamb wave and bulk acoustic wave resonators are demonstrated. High-performance PZT thin films with a thickness of 2.6 μm are prepared on a silicon on insulator wafer by a sputtering deposition process. A highly selective reactive ion etching process is employed for micro-patterning of PZT, platinum electrodes, and SiO₂ insulation layer. Self-actuation of the PZT microcantilevers is demonstrated and the frequency response is characterized using a laser Doppler vibrometer. The frequency response of the Lamb wave resonator is evaluated by measuring its transmission characteristic using a network analyzer. For a Lamb wave resonator with a length of 240 μm and an interdigital period of 80 μm, the 1st order and 2nd resonance frequencies are 15.3 and 41.8 MHz, respectively.     

Development of a color‐tunable polychromatic organic‐light‐emitting‐diode device for roll‐to‐roll manufacturing

A flexible vertically stacked flexible polychromatic color‐tunable OLED has been developed by means of low resistive intermediate electrode technology. The polychromatic OLED has a capability to show 16 million colors with 105% National Television Committee Standard (NTSC) color reproduction. The device can produce arbitrary shape with arbitrary colors, suitable for artistic expressions, just as many as those used in information displays. Independently controlled red, green, and blue light‐emitting layers are stacked vertically. With conventional indium tin oxide technology, because of the temperature restriction, it was quite difficult to achieve low resistance on plastic substrate. The reported numbers were all more than 80 Ω/□. According to the surface mobility control using Fick's law analysis, low sheet resistance 7.34 Ω/□ on plastic film was developed. At first, flexible 7.17 cm² transparent OLED was fabricated for the performance confirmation of transparent electrode. And then polychromatic color‐tunable OLED with the same size were successfully fabricated on plastic. With optical length optimization for each color stack of polychromatic OLED, more than 100% color reproduction in National Television Committee Standard was achieved by stack design. The polychromatic device can be used for colored illumination, as well as for organic‐light‐emitting display pixels for three times emission than conventional pixel design. The device is fabricated on plastic substrate so that the polychromatic organic‐light‐emitting‐diode device is manufacturable with roll‐to‐roll production line.     

Fast crack detection method for large-size concrete surface images using percolation-based image processing

The detection of cracks on concrete surfaces is the most important step during the inspection of concrete structures. Conventional crack detection methods are performed by experienced human inspectors who sketch crack patterns manually; however, such detection methods are expensive and subjective. Therefore, automated crack detection techniques that utilize image processing have been proposed. Although most the image-based approaches focus on the accuracy of crack detection, the computation time is also important for practical applications because the size of digital images has increased up to 10 megapixels. We introduce an efficient and high-speed crack detection method that employs percolation-based image processing. We propose termination- and skip-added procedures to reduce the computation time. The percolation process is terminated by calculating the circularity during the processing. Moreover, percolation processing can be skipped in subsequent pixels according to the circularity of neighboring pixels. The experimental result shows that the proposed approach efficiently reduces the computation cost.     

A Fast Simulation Method Using Overlapping Grids for Interactions between Smoke and Rigid Objects

Recently, many techniques using computational fluid dynamics have been proposed for the simulation of natural phenomena such as smoke and fire. Traditionally, a single grid is used for computing the motion of fluids. When an object interacts with a fluid, the resolution of the grid must be sufficiently high because the shape of the object is represented by a shape sampled at the grid points. This increases the number of grid points that are required, and hence the computational cost is increased. To address this problem, we propose a method using multiple grids that overlap with each other. In addition to a large single grid (a global grid) that covers the whole of the simulation space, separate grids (local grids) are generated that surround each object. The resolution of a local grid is higher than that of the global grid. The local grids move according to the motion of the objects. Therefore, the process of resampling the shape of the object is unnecessary when the object moves. To accelerate the computation, appropriate resolutions are adaptively‐determined for the local grids according to their distance from the viewpoint. Furthermore, since we use regular (orthogonal) lattices for the grids, the method is suitable for GPU implementation. This realizes the real‐time simulation of interactions between objects and smoke.     

An application of quantum finite automata to interactive proof systems

Quantum finite automata have been studied intensively since their introduction in late 1990s as a natural model of a quantum computer working with finite-dimensional quantum memory space. This paper seeks their direct application to interactive proof systems in which a mighty quantum prover communicates with a quantum-automaton verifier through a common communication cell. Our quantum interactive proof systems are juxtaposed to Dwork–Stockmeyer's classical interactive proof systems whose verifiers are two-way probabilistic finite automata. We demonstrate strengths and weaknesses of our systems by studying how various restrictions on the behaviors of quantum-automaton verifiers affect the power of quantum interactive proof systems.     

Simulation of Tearing Cloth with Frayed Edges

Woven cloth can commonly be seen in daily life and also in animation. Unless prevented in some way, woven cloth usually frays at the edges. However, in computer graphics, woven cloth is typically modeled as a continuum sheet, which is not suitable for representing frays. This paper proposes a model that allows yarn movement and slippage during cloth tearing. Drawing upon techniques from textile and mechanical engineering fields, we model cloth as woven yarn crossings where each yarn can be independently torn when the strain limit is reached. To make the model practical for graphics applications, we simulate only tearing part of cloth with a yarn‐level model using a simple constrained mass‐spring system for computational efficiency. We designed conditions for switching from a standard continuum sheet model to our yarn‐level model, so that frays can be initiated and propagated along the torn lines. Results show that our method can achieve plausible tearing cloth animation with frayed edges.     

Interactive Rendering of Interior Scenes with Dynamic Environment Illumination

A rendering system for interior scenes is proposed in this paper. The light reaches the interior scene, usually through small regions, such as windows or abat‐jours, which we call portals. To provide a solution, suitable for rendering interior scenes with portals, we extend the traditional precomputed radiance transfer approaches. In our approach, a bounding sphere, which we call a shell, of the interior, centered at each portal, is created and the light transferred from the shell towards the interior through the portal is precomputed. Each shell acts as an environment light source and its intensity distribution is determined by rendering images of the scene, viewed from the center of the shell. By updating the intensity distribution of the shell at each frame, we are able to handle dynamic objects outside the shells. The material of the portals can also be modified at run time (e.g. changing from transparent glass to frosted glass). Several applications are shown, including the illumination of a cathedral, lit by skylight at different times of a day, and a car, running in a town, at interactive frame rates, with a dynamic viewpoint.     

Higher education in Brazil: an exploratory study based on supply and demand conditions

This paper aims to assess the context of Brazilian higher education institutions, its undergraduate courses and students, comparing their supply and demand conditions. It adopts a three-phase methodological approach: first, an inductive and exploratory step through the longitudinal analysis of data provided by the Brazilian Census of Higher Education, between the years of 2008 and 2014 and the Demographic Census of 2010; second, an analysis between the most important variables identified in the exploratory study (step 1) and its influence on the undergraduate courses’ perceived quality through the General Index of Evaluated Courses, which is responsible for the evaluation of all higher education institutions (HEIs) in Brazil; third, a comparison to other countries is performed, based on the 2015–2016 OECD Education Indicators. Its contribution shall enable HEIs to identify future trends concerning its sustainability conditions, providing subsidies for strategic information. It concludes that offer conditions are diverse, and that, especially in Brazil, demand is increasingly limited for the population considered ideal for undergraduate courses. Also, the expansion of students’ enrollment during the period was desirable and was intertwined with the diversification of higher education establishments and the diversity of programs, due to the national higher education policy system. However, this increasing diversity of HEIs and courses, contrary to what some authors (Teichler in High Educ 56(3):349–379, 1) propose, does not represent an improvement in the number of undergraduate students in Higher Education as most of the students do not conclude their studies.     

Skin Electronics: Next-Generation Device Platform for Virtual and Augmented Reality

Virtual reality (VR) and augmented reality (AR) are overcoming the physical limits of real-life using advances in devices and software. In particular, the recent restrictions in transportation from the coronavirus disease 2019 (COVID-19) pandemic are making people more interested in these virtual experiences. However, to minimize the differences between artificial and natural perception, more human-interactive and human-like devices are necessary. The skin is the largest organ of the human body and interacts with the environment as the site of interfacing and sensing. Recent progress in skin electronics has enabled the use of the skin as the mounting object of functional devices and the signal pathway bridging humans and computers, with opening its potential in future VR and AR applications. In this review, the current skin electronics are summarized as one of the most promising device solutions for future VR/AR devices, especially focusing on the recent materials and structures. After defining and explaining VR/AR systems and the components, the advantages of skin electronics for VR/AR applications are emphasized. Next, the detailed functionalities of skin electronic devices, including the input, output, energy devices, and integrated systems, are reviewed for future VR/AR applications.