The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Many scientific applications rely on the evaluation of elementary transcendental functions (e.g.~sin, cos, exp, log). Software math libraries are a popular approach for realizing such functions, and frequently use series expansion or lookup-table-based techniques. However, software approaches necessarily suffer from the traditional overheads of fetching/decoding instructions, limited cache sizes,...
Dedicated Short Range Communications (DSRC), a promising vehicle-to-vehicle communication technology, has been under active research and large scale DSRC deployment is expected to start shortly. However, before all vehicles are deployed with DSRC, there will be a relatively long partial DSRC deployment period where DSRC-equipped vehicles and non-DSRC-equipped vehicles both exist on roads. More importantly,...
Many scientific applications rely on evaluation of elementary functions. Nowadays, high-level programming languages provide their own elementary function libraries in software by using lookup table and/or polynomial approximation. However, one downside is slow since lookup tables could keep cache thrashing and polynomial approximations require a number of iterations to converge. Thus, elementary functions...
Driving with distraction or losing alertness increases the risk of the traffic accident. The emerging Internet of Things (IoT) systems for smart driving hold the promise of significantly reducing road accidents. In particular, detecting the unsafe hand motions and warning the driver using smart sensors can improve the driver's self-alertness and the driving skill. However, due to the impact of the...
Vehicular Ad Hoc Networks (VANETs) enable vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications that bring many benefits and conveniences to improve the road safety and drive comfort in future transportation systems. Sybil attack is considered one of the most risky threats in VANETs since a Sybil attacker can generate multiple fake identities with false messages to severely impair...
In order to save human lives and reduce injury and property loss, Situation Awareness (SA) information is essential and important for rescue workers to perform the effective and timely disaster relief. The information is generally derived from the shared images via widely used smartphones. However, conventional smartphone-based image sharing schemes fail to efficiently meet the needs of SA applications...
The performance of GPUs on mobile devices is generally the bottleneck of multimedia mobile applications (e.g., 3D games and virtual reality). Previous attempts to tackle the issue mainly migrate GPU computation to servers residing in remote cloud centers. However, the costly network delay is especially undesirable for highly-interactive multimedia applications since a fast response time is critical...
Taxi services and product delivery services are instrumental for our modern society. Thanks to the emergence of sharing economy, ride-sharing services such as Uber, Didi, Lyft and Google's Waze Rider are becoming more ubiquitous and grow into an integral part of our everyday lives. However, the efficiency of these services are severely limited by the sub-optimal and imbalanced matching between the...
Electric vehicles (EVs) play a significant role in the current transportation systems. The main factor that affects the acceptance of existing EV models is the range anxiety problem caused by limited charging stations and long recharge times. Recently, the solar-powered EV has drawn many attentions due to being free of charging limitations. However, the solarpowered EVs may still struggle with the...
Distribution of intangible information goods is experiencing tremendous growth in recent years, which has facilitated a blossoming of information goods economics. As big data develops, there are more and more information goods markets for data trading. In the current of data pricing policies in data trading, there are many metrics to measure the value of data goods, such as the data generation date,...
For mobile apps, user-perceived delays are critical for user satisfaction. According to our measurement, long delays are commonly caused by network and storage I/O operations while short delays are mainly caused by UI rendering. Short delays are not uncommon, which account for 55.3% in our measurement cases. Previous app performance studies have largely focused on I/O operations but the understanding...
Device-free Passive (DfP) indoor localization releases the users from the burden of wearing sensors or carrying smartphones. Instead of locating devices, DfP technology directly locates human bodies. This promising technology upgrades and even redefines many services, such as intruder alarm, fire rescue, fall detection, baby monitoring, etc. Using Wi-Fi based fingerprints, DfP approaches can achieve...
The fast growth of civil drones raises significant security challenges. A legitimate drone may be hijacked by GPS spoofing for illegal activities, such as terrorist attacks. The target of this paper is to develop techniques to let drones detect whether they have been hijacked using onboard motion sensors (accelerometers and gyroscopes). Ideally, the linear acceleration and angular velocity measured...
State-of-the-art indoor localization techniques can reach high localization accuracy, but rely on widely deployed infrastructure which may be absent in less developed regions. To achieve infrastructure-free indoor localization, researchers have proposed to use the inertial sensors on the mobile devices to update the users potential locations by walking steps. Such methods are known to accumulate errors...
With the increasing demand of the big data processing and the personalized services in the Internet, the current service platforms such as cloud are becoming hard to meet the requirement of multiple-level quality of services (QoS) within a short execution time. In this paper, an on-site elastic autonomous service network named SEA is proposed to cope with the above problems by utilizing the available...
Large-scale charging stations become indispensable infrastructure to support the rapid proliferation of electric vehicles. Their operation modes have drawn great attention from both academia and industry. One promising mode called park-and-charge has been recently introduced. This new mode allows customers to park their electric vehicles at a parking lot, where the vehicles are charged during the...
The increasing market share of electric vehicles (EVs) makes charging facilities indispensable infrastructure for integrating EVs into the future intelligent transportation systems and smart grid. One promising facility called fast charging reservation(FCR) system was recently proposed. It allows people to reserve fast chargers ahead of time. In this system, fast chargers are the most scarce resource...
Since the first log analyzer was invented by Dr. Stephen Turner in 1995, web-analytics has been widely used on the Internet to achieve goals as making smart business decisions, improve business website performance, processes and their bottom lines, etc. Although web-analytics has been widely used in the economic field, yet it has not been utilized in the education domain. So this is the first introduction...
Wireless sensor networks (WSNs) have recently gained a great deal of attention as a topic of research, with a wide range of applications being explored. Bulk data dissemination is a basic building block for sensor network applications. The problem of designing efficient bulk data dissemination protocols has been addressed in a number of recent studies. The problem of mathematically analyzing the performance...
Properly optimizing the setting of configuration parameters can greatly improve performance, especially in the presence of changing workloads. This paper explores approaches to online optimization of the Apache web server, focusing on the MaxClients parameter (which controls the maximum number of workers). Using both empirical and analytic techniques, we show that MaxClients has a concave upward effect...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.