Indoor Human Navigation Systems: A Survey <s> Localization <s> Traditionally, geography has paid relatively little attention to disabled or disadvantaged populations. As society has concerned itself more with problems of dealing with the blind, the physically handicapped, the retarded, the deaf, the socioeconomically destitute and homeless, and other special populations, the discipline of geography has dragged its feet in terms of examining how its expertise can be used to help understand and solve the many problems these special populations encounter in normal commerce with physical and built environments. In this paper I outline some general and some specific suggestions regarding the way geographers can invoke their skills and knowledge to deal with sets of problems faced by these special populations. The paper is designed to make suggestions both for instructional purposes (i.e., providing a sufficiently wide topical coverage for potential course-work in the area), and to identify specific future research challenges. The combined effect is to suggest that geographical study of the disabled could represent a new systematic area of geographic concentration that would combine micro and macro approaches, and facilitate the development of new geographic theory, methods, and applications. <s> BIB001 </s> Indoor Human Navigation Systems: A Survey <s> Localization <s> In this paper we present a new system that assists blind users in orienting themselves in indoor environments. We developed a sensor module that can be handled like a flashlight by a blind user and can be used for searching tasks within the three-dimensional environment. By pressing keys, inquiries concerning object characteristics, position, orientation and navigation can be sent to a connected portable computer, or to a federation of data servers providing models of the environment. Finally these inquiries are acoustically answered over a text-to-speech engine. <s> BIB002 </s> Indoor Human Navigation Systems: A Survey <s> Localization <s> Because of its promise to revolutionize global supply chain management (SCM) systems, Ultra High Frequency (UHF) Radio Frequency Identification (RFID) was recently the cause of much optimism. Wal-Mart mandated its top 100 suppliers to begin using RFID on January 1st, 2005; this day was viewed as a watershed day in the industry. However, that date has come and gone, and the expected rapid industry adoption of RFID has not taken place. This paper explores the existing challenges and obstacles to RFID's quick adoption, the potential resolutions and approaches to the challenges, and the migration strategies to expand the RFID industry. <s> BIB003
All navigation systems must include a basic form of localization, i.e., the determination of a user's position and/or orientation. Localization methods can be grouped into four different techniques: (1) dead-reckoning, (2) directsensing, (3) triangulation, and (4) pattern-recognition, which are discussed in the following subsections. Outdoor navigation systems typically achieve accurate localization at a low cost using GPS. Indoor navigation systems have to rely upon different techniques, as GPS cannot be used indoors. Currently no indoor navigation system has achieved large-scale deployment due to issues with cost, accuracy and usability. * Cost: indoor navigation systems are prohibitively expensive to install as they typically require extensive augmentation of the physical environment to be navigated in. For example, although the cost of an RFID tag is low, installing them at a large scale, such as a campus environment, is often costly. This cost also depends on physical constraints. For instance, if an indoor environment has carpets, installing tags is relatively cheap, but costs increase significantly when an environment has concrete or marble floors BIB003 . Other techniques require expensive sensing equipment to be carried or worn by the user, for example, cameras and supporting computing equipment may add to the cost of the system significantly  . * Usability: carrying a multitude of sensors and supporting computing equipment for localizing the user may thwart the usability as well as impede the mobility of the user, which is undesirable especially in the case of users with visual impairments who already carry assistive equipment such as a cane or a Braille reader with them. * Accuracy: while an accuracy of 3 feet is acceptable in most cases for GPS based localization, indoor navigation may require a higher precision. For example, to successfully navigate to a location, an accuracy of 3 feet may not allow for distinguishing between adjacent doors. On the other hand indoor environments are more physically constrained by walls and distinguishable landmarks such as doors and veering becomes less of a problem than for outdoor environments. For indoor navigation systems to become ubiquitous, their installation cost needs to decrease significantly. Systems that do not require expensive augmentation  BIB002 or that use low-cost, commercially off-the-shelf hardware are more likely to be implemented at a large scale. At the same time, such inexpensive systems need to provide at least as precise localization as their more expensive counterparts. This tradeoff may be difficult to circumvent, but hybrid indoor navigation system could be developed that trade off accuracy versus cost. Low accuracy localization can be used for areas where high precision is not required, such as hallways, where veering is constrained by the physical environment to minimize the installation cost. Large scale deployment of indoor navigation systems lead to greater independence of users with visual impairments and could significantly improve their quality of life BIB001 .