Measuring and analysing vibration motors in insoles via accelerometers

Purpose: Falling is a major public health concern among elderly people, and they often cause serious injuries1,2. They most frequently occur during walking and are associated with the chronic deterioration in the neuromuscular and sensory systems, as well as with ankle muscle weakness and lower endurance of these muscles to fatigue1,3. Vibrating insoles, providing a subsensory mechanical noise signal to the plantar side of the feet, may improve balance in healthy young and older people and in patients with stroke or diabetic neuropathy4. The object of this study is to find the most suitable vibrator to put into the insole which can effectively improve the balance control of the elderlies. Method: We choose three different vibration actuators (micro vibration motor, brushless motor and eccentric motor) with two different weights on the insole. First, we put three same motors and two accelerometers on the insole, as shown in Figure1, then attach another layer on both side of the insole. Second, connect the motors to the power supply and the accelerometer to NI PXI-1033 spectrum analyzer which is used to collect the accelerometers' data. At last, using Fast Fourier Transform (FFT) to analyze and compare the results to see which motor is the most stable and suitable to put into the insole. Results & Discussion: The results showed that the most stable one is the brushless motor. The reason why the frequency is stable is that the relationship between voltage and frequency is linear, and the error is small through continuous measurements. On the other hand, when a person weight 55 kg stands on the insole, the frequency isn't affected by the weight. These two results appear very similar to each other, as shown in Figure 2. According to the result, we use the brushless motor to be our vibrator in the insole, and hope this will help the elderlies improve their balance control ability more efficiency

Boosting the precision of virtual call integrity protection with partial pointer analysis for C++

© 2017 Association for Computing Machinery. We present, Vip, an approach to boosting the precision of Virtual call Integrity Protection for large-scale real-world C++ programs (e.g., Chrome) by using pointer analysis for the first time. Vip introduces two new techniques: (1) a sound and scalable partial pointer analysis for discovering statically the sets of legitimate targets at virtual callsites from separately compiled C++ modules and (2) a lightweight instrumentation technique for performing (virtual call) integrity checks at runtime. Vip raises the bar against vtable hijacking attacks by providing stronger security guarantees than the CHA-based approach with comparable performance overhead. Vip is implemented in LLVM-3.8.0 and evaluated using SPEC programs and Chrome. Statically, Vip protects virtual calls more effectively than CHA by significantly reducing the sets of legitimate targets permitted at 20.3% of the virtual callsites per program, on average. Dynamically, Vip incurs an average (maximum) instrumentation overhead of 0.7% (3.3%), making it practically deployable as part of a compiler tool chain

Deep Learning for Single Image Super-Resolution: A Brief Review

Single image super-resolution (SISR) is a notoriously challenging ill-posed problem, which aims to obtain a high-resolution (HR) output from one of its low-resolution (LR) versions. To solve the SISR problem, recently powerful deep learning algorithms have been employed and achieved the state-of-the-art performance. In this survey, we review representative deep learning-based SISR methods, and group them into two categories according to their major contributions to two essential aspects of SISR: the exploration of efficient neural network architectures for SISR, and the development of effective optimization objectives for deep SISR learning. For each category, a baseline is firstly established and several critical limitations of the baseline are summarized. Then representative works on overcoming these limitations are presented based on their original contents as well as our critical understandings and analyses, and relevant comparisons are conducted from a variety of perspectives. Finally we conclude this review with some vital current challenges and future trends in SISR leveraging deep learning algorithms.Comment: Accepted by IEEE Transactions on Multimedia (TMM

Patrones de distribución de individuos longevos de plantas relictas en los alrededores de la montana Fanjingshan en China: implicaciones para su conservación in situ

The mountain areas in south-central China are widely recognized as refugia of relict plants during the late Neogene and Quaternary periods. In this paper, we try to explore the distribution patterns of natural habitats and to exactly locate the refugia of relict species around Fanjingshan Mountain using dendrological data of long-lived individuals (≥ 100 years old). Six typical relict plants were found around the mountain, i.e. Cyclocarya paliurus, Ginkgo biloba, Liriodendron chinense, Pinus massoniana, Podocarpus macrophyllus, and Taxus chinensis. The long-lived individuals were divided into three classes according to their ages: Class-I (≥ 500 years), Class-II (300–499 years), and Class-III (100–299 years). Our results showed that the south-west region to the mountain was the main distribution area of Class-I trees of G. biloba and T. chinensis, most of which occurring in the same small village (Yangliu Village of Yinjiang County). The north-east region harboured all the six relict species. Floristic analyses also indicated these two regions were very similar in tree growth as measured by DBH (diameter at breast height of 1.3 m). Thus, these two areas would have provided long-term suitable habitats for relict species. The south-west region, especially the small village Yangliu, should be given highest priority for in situ conservation of relict species and other rare and endangered plants. Attention should also be paid to the north-east region for its very high species diversity of relict species.Las áreas montañosas de la región centro-sur de China están ampliamente reconocidas por su papel como refugio de plantas relictas durante la última etapa del Neógeno y el Cuaternario. En el presente trabajo se intentan explorar los patrones de distribución de los hábitats naturales y la localización exacta de los refugios para especies vegetales relictas en los alrededores de la montaña Fanjinshan, mediante el empleo de datos dendrológicos de individuos longevos (≥ 100 años). En el área de estudio se encontraron seis especies vegetales típicamente relictas: Cyclocarya paliurus, Ginkgo biloba, Liriodendron chinense, Pinus massoniana, Podocarpus macrophyllus y Taxus chinensis. Los individuos longevos se dividieron en tres categorías de acuerdo con su edad estimada: individuos de Clase I (≥ 500 años), de Clase II (300–499 años) y de Clase III (100–299 años). Nuestros resultados muestran que la región situada al suroeste de la montaña se corresponde con la principal área de distribución de los árboles de Clase I de G. biloba y T. chinensis, localizándose la mayor parte de éstos en los alrededores de una pequeña aldea (Yangliu, en el condado de Yinjiang). La región situada al noreste de Fanjinshan alberga, por su parte, las seis especies relictas, y los análisis florísticos muestran una elevada similaridad entre ambas regiones por lo que respecta al crecimiento arbóreo medido como DBH [diámetro a la altura del pecho (1,3 m)]. Por consiguiente, estas dos regiones habrían proporcionado hábitats adecuados para la supervivencia de especies relictas. La región suroeste, y en especial la aldea de Yangliu, deben recibir la máxima prioridad para la conservación in situ de especies relictas (y otras especies raras y amenazadas). La región noreste también debe priorizarse dada su elevada diversidad de especies relictas

Improving Ant Collaborative Filtering on Sparsity via Dimension Reduction

Recommender systems should be able to handle highly sparse training data that continues to change over time. Among the many solutions, Ant Colony Optimization, as a kind of optimization algorithm modeled on the actions of an ant colony, enjoys the favorable characteristic of being optimal, which has not been easily achieved by other kinds of algorithms. A recent work adopting genetic optimization proposes a collaborative filtering scheme: Ant Collaborative Filtering (ACF), which models the pheromone of ants for a recommender system in two ways: (1) use the pheromone exchange to model the ratings given by users with respect to items; (2) use the evaporation of existing pheromone to model the evolution of users’ preference change over time. This mechanism helps to identify the users and the items most related, even in the case of sparsity, and can capture the drift of user preferences over time. However, it reveals that many users share the same preference over items, which means it is not necessary to initialize each user with a unique type of pheromone, as was done with the ACF. Regarding the sparsity problem, this work takes one step further to improve the Ant Collaborative Filtering’s performance by adding a clustering step in the initialization phase to reduce the dimension of the rate matrix, which leads to the results that K<<#users, where K is the number of clusters, which stands for the maximum number of types of pheromone carried by all users. We call this revised version the Improved Ant Collaborative Filtering (IACF). Experiments are conducted on larger datasets, compared with the previous work, based on three typical recommender systems: (1) movie recommendations, (2) music recommendations, and (3) book recommendations. For movie recommendation, a larger dataset, MoviesLens 10M, was used, instead of MoviesLens 1M. For book recommendation and music recommendation, we used a new dataset that has a much larger size of samples from Douban and NetEase. The results illustrate that our IACF algorithm can better deal with practical recommendation scenarios that handle sparse dataset

Resisting skew-accumulation for time-stepped applications in the cloud via exploiting parallelism

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Time-stepped applications are pervasive in scientific computing domain but perform poorly in the cloud because these applications execute in discrete time-step or tick and use logical synchronization barriers at tick boundaries to ensure correctness. As a result, the accumulated computational skew and communication skew that were unsolved in each tick can slow downtime-stepped applications significantly. However, the existing solutions have focused only on the skew in each tick and thus cannot resist the accumulation of skew. To fill in this gap, an efficient approach to resisting the accumulation of skew is proposed in this paper via fully exploiting parallelism among ticks. This new approach allows the user to decompose much computational part (also called asynchronous part) of the processing for an object, into several asynchronous sub-processes which are dependent on one data object. Each sub-process from different ticks can then proceed in advance using the idle time whenever the needed data object is available, redressing the negative effects caused by accumulated unsolved computational and communication skew. To efficiently support such an approach, a data-centric programming model and also a runtime system, namely AsyTick, coupled with an ad hoc scheduler are developed. Experimental results show that the proposed approach can improve the performance of time-stepped applications over a state-of-the-art computational skew-resistant approach up to 2.53 times.This paper is supported by China National Natural Science Foundation under grant No. 61272408, 61322210, National High-tech Research and Development Program of China (863 Program) under grant No.2012AA010905, CCCPC Youngth Talent Plan, Doctoral Fund of Ministry of Education of China under grant No. 20130142110048

The influence of structural defects on intra-granular critical currents of bulk MgB2

Bulk MgB2 samples were prepared under different synthesis conditions and analyzed by scanning and transmission electron microscopy. The critical current densities were determined from the magnetization versus magnetic field curves of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow cooling process, the oxygen dissolved in bulk MgB2 at high synthesis temperatures can segregate and form nanometer-sized coherent precipitates of Mg(B,O)2 in the MgB2 matrix. Magnetization measurements indicate that these precipitates act as effective flux pinning centers and therefore significantly improve the intra-grain critical current density and its field dependence.Comment: 4 pages, 4 figures, to be published in IEE Transactions in Applied Superconductivit

Finite-Time Bounded Tracking Control for Linear Discrete-Time Systems

© 2018 Fucheng Liao et al. A finite-time bounded tracking control problem for a class of linear discrete-time systems subject to disturbances is investigated. Firstly, by applying a difference method to constructing the error system, the problem is transformed into a finite-time boundedness problem of the output vector of the error system. In fact, this is a finite-time boundedness problem with respect to the partial variables. Secondly, based on the partial stability theory and the research methods of finite-time boundedness problem, a state feedback controller formulated in form of linear matrix inequality is proposed. Based on this, a finite-time bounded tracking controller of the original system is obtained. Finally, a numerical example is presented to illustrate the effectiveness of the controller