Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Hidden Markov Models (HMMs) are one of the most important techniques to model and classify sequential data. Maximum Likelihood (ML) and (parametric and non-parametric) Bayesian estimation of the HMM parameters suffers from local maxima and in massive datasets they can be specially time consuming. In this paper, we extend the spectral learning of HMMs, a moment matching learning technique free from...
Inertial Measurement Units (IMU) are essentially a combination of acceleration and rotation rate sensors, generating acceleration and attitude information. For strategic applications, like outer space launchers, traditional macro-scale technologies are currently employed, owing to their very high accuracies and low drift. But they are very bulky and power consuming. Recent advancements in MEMS technology...
Signal reconstruction from the smallest possible Fourier measurements has been a key motivation in the compressed sensing research. We present an approach that exploits the interdependency and structural sparsity of partial derivatives for lowering the sampling rates necessary for accurate reconstruction. Our experiments show that for signals that are sparse in the gradient domain our proposed method...
Localization of audio sources is an important research problem, e.g., to facilitate noise reduction. In the recent years, the problem has been tackled using distributed microphone arrays (DMA). A common approach is to apply direction-of-arrival (DOA) estimation on each array (denoted as nodes), and then map the DOA estimates to a location. In practice, however, the individual nodes contain few microphones,...
Recent events highlight the need for technologies that provide timely identification and geo-location of objects lost within a geographic area that could span tens of thousands of square kilometers over both land and water. Mission critical systems for search and rescue require technologies that provide timely identification and geolocation of objects within these vast geographic areas. Even though...
A three-dimensional accelerometer was incorporated into a balance board to report real-time ankle attitudes during ankle sprain rehabilitative treatment. The design consisted of an embedded sensory module wirelessly linked to an Android mobile device with a graphic user interface to assess proprioceptive improvements. Preliminary results demonstrated an ability to report ankle attitude at a rate of...
As of January 2014, 58 percent of Americans over the age of 18 own a smart phone. Of these smart phones, Android devices provide some security by requiring that third party application developers declare to users which components and features their applications will access. However, the real time environmental sensors on devices that are supported by the Android API are exempt from this requirement...
The interaction of a cyber-physical system (CPS) may impose additional constraints upon cyber aspects of the system. For instance, sensing and actuation often require nonpreemption to ensure “accuracy” in data acquisition (e.g., radar sensors in automotive a cruise control system). Furthermore, CPS may require that a system adapts to changing environment which requires support for multiple operating...
The growth of power consumption in ICT infrastructures emphasizes the importance of monitoring their usage and finding available room for improvement. Users can choose among several existing tools to determine the energy profile of a running application in order to provide more sustainable software. We conducted a field study in the SURFsara data center and we experimented with the tools available,...
The ability of SMAs to respond reversibly to an external stimulus by modifying their dimensions can be used to generate motion or force in electromechanical devices and micro-machines. There are several works that demonstrate SMAs are serious alternatives as micrometric actuators, obtaining accuracies around 3 µm in position control if high-quality position sensors, such as LVDTs, are used to feedback...
Ultra WideBand(UWB) Impulse Radio (IR) has huge advantages in target identification for its broad band, good concealment and strong ability to penetrate obstacles. We apply the UWB-IR technology theory in target identification under the foliage environment. It is different from the traditional radar and wireless sensor network (WSN), for it combines forward communication and target identification...
This paper focuses on the trustworthiness of data gathered from different sources, including crowdsensing and crowdsourcing, in pervasive systems. The specific focus is on mPASS (mobile Pervasive Accessibility Social Sensing), a system devoted to support mobile users with accessibility needs in a smart city context. mPASS is in charge of collecting data about urban and architectural barriers and facilities,...
Predicting the location of a user in indoor settings in a practical and energy-efficient manner is (still) a very non-trivial task. The latest challenge in indoor localization is not to design specialized sensors but to design and implement practical data fusion methods using the already available technologies. Current state-of-the-art indoor localization techniques utilize Wi-Fi and a variety of...
We present an integrated approach for the calibration and registration of color and depth (RGBD) sensors into a joint coordinate system without explicitly identifying intrinsic or extrinsic camera parameters. Our method employs a tracked checkerboard to establish a number of correspondences between positions in color and depth camera space and in world space. These correspondences are used to construct...
Star Sensor, also known as star-tracker, is a high-accuracy 3-axis attitude sensor used onboard spacecrafts. It processes stars from a sky image captured using an area imaging detector (generally 1k × 1k pixels Charge Coupled Device) to generate attitude information. Its accuracy about the boresight is poorer than about the cross-axes. This is improved by using two sensor heads with staggered Fields-Of-View...
Sensors easily become faulty and unreliable subject to limited battery and insecurity. Data Fault is one of traditional faults in the wireless sensor networks. Data fault mainly uses distributed method through exchanging neighbors' measurements and voting for decision. But the detection accuracy performance is easily influenced by unbalanced fault distribution. Based on this, we propose the k-means...
Efficient evacuation of large buildings which seat more than twenty thousand people is a major challenge for building management authorities. Although many enterprise buildings have access control to count those entering various areas, such controls need to be switched off at times of emergency to avoid people getting trapped at a particular location. Hence, counting people during evacuation remains...
Wrist worn smart devices such as smart watches become increasingly popular. As those devices collect sensitive personal information, appropriate user authentication is necessary to prevent illegitimate accesses to those devices. However, the small form and function-based usage of those wearable devices pose a big challenge to authentication. In this paper, we study the efficacy of motion based authentication...
We explore the use of gesture recognition on a wrist-worn smartwatch as an enabler of an automated eating activity (and diet monitoring) system. We show, using small-scale user studies, how it is possible to use the accelerometer and gyroscope data from a smartwatch to accurately separate eating episodes from similar non-eating activities, and to additionally identify the mode of eating (i.e., using...
In this paper we present a framework for Quality of Information (QoI)-aware networking. QoI quantifies how useful a piece of information is for a given query or application. Herein, we present a general QoI model, as well as a specific example instantiation that carries throughout the rest of the paper. In this model, we focus on the tradeoffs between precision and accuracy. As a motivating example,...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.