Authorization or access control limits the actions a user may perform on a computer system, based on predetermined access control policies, thus preventing access by illegitimate actors. Access control for the Internet of Things (IoT) should be tailored to take inherent IoT network scale and device resource constraints into consideration. However, common authorization systems in IoT employ conventional schemes, which suffer from overheads and centralization. Recent research trends suggest that blockchain has the potential to tackle the issues of access control in IoT. However, proposed solutions overlook the importance of building dynamic and flexible access control mechanisms. In this paper, we design a decentralized attribute-based access control mechanism with an auxiliary Trust and Reputation System (TRS) for IoT authorization. Our system progressively quantifies the trust and reputation scores of each node in the network and incorporates the scores into the access control mechanism to achieve dynamic and flexible access control. We design our system to run on a public blockchain, but we separate the storage of sensitive information, such as user’s attributes, to private sidechains for privacy preservation. We implement our solution in a public Rinkeby Ethereum test-network interconnected with a lab-scale testbed. Our evaluations consider various performance metrics to highlight the applicability of our solution for IoT contexts.

The popularity of female soccer is increasing as well as the number of females playing soccer. Similarly, over the last twenty or so years, research in soccer has increased significantly, but a large disparity exists in the volume of studies involving male and female players. As a consequence of this, female players remain less well understood compared to males. The purpose of the present narrative review was to describe morphological characteristics, physiological demands, physical abilities and injuries in female soccer players. Physiological demands are similar between men’s and women’s soccer, but competitive women’s matches were characterized by nearly 33% less distance covered, although at higher intensity levels (maximum speeds greater than 15 km/h) than typically found in the men’s game. Sub-elite female players also tended to run less at higher intensity levels at the end of both halves in comparison with elite female players. High intensity running is an important factor of success in soccer since many critical moments of the game occur under this condition. The ability to rapidly change direction also determined elite, sub-elite and amateur levels. The implementation of functional training, which focused on soccer-specific drills and plyometric exercises, to improve explosive power, may improve conditioning in female soccer players as well as decrease the risk of injuries which was 3-8 times higher in females compared to males. This review presents an in-depth overview of the most influential factors for determining success in female soccer.

The purpose of this study was to examine the effects of medicine ball training on the strength and power in young female handball athletes. Twenty-one young female handball players (age, 16.9 ± 1.2 years) were randomly assigned to experimental and control groups. Experimental group (n = 11) participated in a 12-week medicine ball training program incorporated into the regular training session, whereas controls (n = 10) participated only in the regular training. Performance in the medicine ball throws in standing and sitting positions, 1 repetition maximum (1RM) bench and shoulder press, and power test at 2 different loads (30 and 50% of 1RM) on bench and shoulder press were assessed at pre- and posttraining testing. The athletes participating in the medicine ball training program made significantly greater gains in all medicine ball throw tests compared with the controls (p < 0.01). Also, the experimental group made significantly greater gains in bench and shoulder press power than control group (p < 0.05). Both training groups (E) and (C) significantly (p < 0.05) increased 1RM bench and shoulder strength, with no differences observed between the groups. Additionally, medicine ball throw tests showed stronger correlation with power tests, than with 1RM tests. These data suggest that 12-week medicine ball training, when incorporated into a regular training session, can provide greater sport-specific training improvements in the upper body for young female handball players.

We consider the problem of data collection from a network of energy harvesting sensors, applied to tracking mobile assets in rural environments. Our application constraints favor a fair and energy-aware solution, with heavily duty-cycled sensor nodes communicating with powered base stations. We study a novel scheduling optimization problem for energy harvesting mobile sensor network, that maximizes the amount of collected data under the constraints of radio link quality and energy harvesting efficiency, while ensuring a fair data reception. We show that the problem is NP-complete and propose a heuristic algorithm to approximate the optimal scheduling solution in polynomial time. Moreover, our algorithm is flexible in handling progressive energy harvesting events, such as with solar panels, or opportunistic and bursty events, such as with Wireless Power Transfer. We use empirical link quality data, solar energy, and WPT efficiency to evaluate the proposed algorithm in extensive simulations and compare its performance to state-of-the-art. We show that our algorithm achieves high data reception rates, under different fairness and node lifetime constraints.