Academic literature on the topic 'Relative directional positioning'

‘Rigid plates of lithosphere’ explains that because of the lithosphere’s strength, essentially rigid plates of lithosphere move with respect to one another across the surface of the Earth. Their rigidity allows their rates of relative motion and of their total displacements to be described by rotations about axes passing through the centre of the Earth, or poles of rotation. Global Positioning System (GPS) measurements corroborate the inferences drawn both from rates of seafloor spreading determined using magnetic anomalies and from directions of relative plate motion determined using orientations of transform faults and fault plane solutions of earthquakes along plate boundaries.

The rolling machine element is indispensable for realizing high-precision and high-speed relative motion. In addition, its positioning accuracy is approaching the nanometer order, and its importance is expected to increase in the future. However, since the rolling elements and the raceways are mechanically in contact, various nonlinear phenomena occur. This complicated phenomenon must be clear by theoretically and experimentally. This chapter describes the nonlinear friction behavior occurred with rolling contact condition and its effect on the dynamics of bearings. First, the characteristics of the non-linear friction caused by rolling machine elements and the nonlinear friction modeling method using the Masing rule are described. From the numerical analysis using the friction model, it is clarified that the motion accuracy decreases due to sudden velocity variation caused by nonlinear friction. Also, the author show that the resonance phenomenon and force dependency of the dynamic characteristics of rolling machine element due to the nonlinear friction. Finally, the author indicates nonlinear friction influences on the dynamic characteristics in the directions other than the feed direction.

A virtual “privilege walk” is an interactive survey that helps a respondent consider the role of unfair advantage in social relationships and where he or she stands in relation to social power based on family life, access to resources, social positioning and embodiment, and other factors. In 2014, at Kansas State University, an open-access virtual privilege walk was created to align with the launch of a graduate social justice certificate program. This chapter explores that privilege walk instrument through (1) a computational text analysis, (2) descriptive statistics around the responses to the instrument, and (3) an exploratory factor analysis (based on three years of anonymous data) to see how well the underlying factors align with the intended factors and to find directions for improving the instrument.

Geocasting is a subset of conventional multicasting problem. Geocasting means to deliver a message or data to a specific geographical area. Routing refers to the activities necessary to route a message in its travel from source to the destination node. The routing of a message is very important and relatively difficult problems in the context of Ad-hoc Networks because nodes are moving very fast, network load or traffic patterns, and topology of the network is dynamical changes with time. In this chapter, different geocast routing mechanisms used in both Mobile Ad-hoc Networks and Vehicular Ad-hoc Networks. The authors have shown a strong and in-depth analysis of the strengths and weaknesses of each protocol. For delivering geocast message, both the source and destination nodes use location information. The nodes determine their locations by using the Global Positioning System (GPS). They have presented a comprehensive comparative analysis of existing geocast routing protocols and proposed future direction in designing a new routing protocol addressing the problem.

The past decade has seen advances in wireless network technologies and an explosive growth in the diversity of portable computing devices such as laptop computers, handheld personal computers, personal digital assistants (PDAs), and smart phones with Internet access. Wireless networking technologies and portable devices enable users to access information in an “anytime, anywhere” fashion. For example, a mobile user (MU) on the highway may query local weather, traffic information, nearby gas stations, next rest areas, or restaurants within 10 miles. Such new demands introduce a new type of services, location-based services (LBS), where certain location constraints (e.g., the user’s current location) are used in the service provision. The idea of queries with location constraints is originally introduced by Imielinski and Badrinath (1992), in which mobile users are likely to query information relating to their current positions, leading to the need for LBS. Such services are also termed as location dependent information services (LDIS) in Lee, Lee, Xu, and Zheng (2002). LBS system is the context sensitive systems in a mobile computing environment that consider the user’s location as a significant and dynamic factor affecting the information and services delivered to the users. The major LBS applications include: • Destination guides with maps, driving directions, and real time prompt • Location-based traffic and weather alerts • Wireless advertising and electronic coupons to nearby mobile devices • Movie, theatre and restaurant location and booking • Store locating applications helping users to find the desired services • Telematics-based roadside assistance (e.g., OnStar from General Motors) • Personal content and messaging (Live Chat with friends) • Mobile Yellow Pages provide local information • Information Services (News, Stocks, Sports) • E911: (Wireless carriers provide wireless callers’ numbers and locations.) Generally, LBS services can be classified into three general categories: telematics LBS, Internet LBS, and wireless LBS (Telc). Telematics LBS is the integration of wireless communications, vehicle monitoring systems, and location devices. Telematics LBS applications include automated vehicle location, fleet tracking, online navigation, and emergency assistance. For example, a trucking company can track all their fleet, proactively warn about traffic ahead, and estimate the arrival time. Commercial LBS providers are beginning to offer important management applications that help direct vehicle fleets and ensure optimal usage of key assets. Telematics LBS is a multibillion dollar service industry and is currently the largest segment of the LBS market (Telc). Internet LBS provide Internet users the services relevant to their specified locations. Because they use a user-specified location instead of the user’s current location, no positioning technology is required. For example, one can find turn-by-turn driving direction from one location to another and search for tour information about the destination. These services are targeting applications with stationary users, relatively powerful computers, and reliable network connections. As a result, Internet LBS support sophisticated services, such as local business searching and comparison, trip planning, online virtual tours, and so forth. Wireless LBS deliver location relevant content to cell phones, PDAs, and other wireless devices. Equipped with automated positioning technologies, MUs can query local weather, nearby traffic information, and local businesses close to them. For example, a user can search neighboring post office or coffer shop from the PDA. The wireless LBS market is currently in a nascent stage, but it will potentially become the largest segment of the LBS market. The deployment of third generation (3G) mobile network, which support handsets that are both mobile and location sensitive, will lead to more wireless LBS subscribers and more useful LBS applications.