Site-specific weed management can increase crop production efficiency by minimizing herbicide input costs without compromising crop yields. A reduction in herbicide inputs resulting from site-specific weed management may also decrease the probability level of nonpoint pollution compared with conventional herbicide applications. A 4.5-ha field was selected to compare site-specific and conventional weed management techniques in 1997 and 1998 at Knoxville, TN. Variable rate applications (VRAs) of atrazine preemergence (PRE) followed by dicamba postemergence (POST) were investigated for the reduction of herbicide inputs and their resulting impact on weed control and corn yield. VRAs of atrazine were on the basis of weed density data collected in 1996. VRAs of dicamba were according to common cocklebur density evaluations within the field. Compared with conventional applications, atrazine usage was decreased by 43 and 32% in the site-specific application treatments in 1997 and 1998, respectively. VRAs of dicamba reduced herbicide inputs by greater than 45% for 1997 and 1998. Corn yields were similar for the conventional and site-specific treatments in both years. On the basis of these data, site-specific herbicide applications have the greatest potential and least risk for managing weeds when POST or PRE + POST variable rate herbicide applications are used.

Background: Out-of-home mobility refers to the realization of trips outside the home, by foot or by other means of transportation. Although out-of-home mobility is important for the well-being of older people with cognitive impairment, its importance for their caregivers is not clear. This study aims to clarify the relationship between caregiving burden and out-of-home mobility of care-recipients using Global Positioning Systems (GPS) technology.

Methods: Seventy-six dyads (care-recipients and caregivers) were recruited from a psychogeriatric center, where they underwent cognitive assessment, followed by psychosocial interviews at home. Care-recipients received GPS tracking kits to carry for a period of four weeks, whenever they left home. Mobility data and diagnostic and psychosocial data were examined in relation to caregiver burden.

Results: The strongest predictors of burden were care-recipients’ lower cognitive status and more time spent walking out-of-home. An interaction was found between cognitive status and time spent walking in relation to caregiver burden. The relationship between walking and burden was stronger among caregivers of care-recipients with dementia than caregivers of care-recipients with no cognitive impairment or mild cognitive impairment. Care-recipients’ behavioral and emotional states were also positively related to caregiver burden.

Conclusions: The findings stress the importance of maintaining older persons’ out-of-home mobility during cognitive decline.

The localization problem in mobile robotics can be defined as the search of the robot's coordinates in a known environment. If there is no information about the initial location, we are talking about global localization. In this work, we have developed an algorithm that solves this problem in a three-dimensional (3D) environment using evolutionary computation concepts. The method has been called RELF-3D and has many features that make it very robust and reliable: thresholding and discarding mechanisms, different cost functions, effective convergence criteria, and so on. The resulting global localization module has been tested in numerous experiments and the most important improvement obtained is the accuracy of the method, allowing its application in manipulation tasks.

A system including Global Positioning Systems (GPS) and digital cartography is a good solution to carry out vehicle's guidance. However, it has inconveniences like high sensibility to multipath and interference when the GPS signal is blocked by external agents. Another system is mandatory to avoid this error. This paper presents a cooperative system based on GPS and Inertial Navigation Systems (INS) for automated vehicle position. The control system includes a decision unit to choose which value is the correct. In case GPS is working at top precision, it takes the control. On the other part, GPS signal can be lost and inertial control system guides the car in this occasion. A third possibility is contemplated: we receive the signal from GPS but the accuracy is over one meter. Now, position value is obtained by means of both systems. Experimental results analyze two situations: guidance in an urban area where GPS signal can be occluded by buildings or trees during short time intervals and the possibility of loss of the signal in long time to simulate the circulation in tunnels. Good results have been observed in tests and it demonstrates how a cooperative system improves the automated vehicle guidance.