679 research outputs found
Design Methodology for Unmanned Aerial Vehicle (UAV) Team Coordination
Unmanned Aerial Vehicle (UAV) systems, despite having no onboard human pilots, currently
require extensive human involvement to accomplish successful mission operations. Further,
successful operations also require extensive colalboration between mission stakeholders,
including operators, mission commanders, and information consumers (e.g. ground troops relying
on intelligence reports in their area).
Existing UAV system interfaces provide little to no support for collaboration between remote
operators or for operators to collaborate with information consumers. As reliance on UAVs
continues to increase in military and civilian operations, this lack of support for collaboration will
likely become a substantial limitation of existing UAV systems.
In order to introduce effective collaboration support to UAV system interfaces, it is essential to
understand, and be able to derive system design requirements that address, the necessary group
interactions that occur in UAV task enviroments. However, few collaborative requirements
analysis methods exist, and to our knowledge, no method exists that captures design requirements
for collaborative decision making in complex, time-critical environments.
This report describes the development of a new design requirements analysis method for deriving
information and functional requirements that address the collaboration needs of UAV (and other
complex task) operators, and the needs of stakeholders interacting with these operators. More
specifically, theis method extends a recently developed requirements analysis method, called the
Hybrid Cognitive Task Analysis (CTA) method, which enables the generation of information and
functional requirements for futuristic UAV system interfaces. The original Hybrid CTA method
focused on deriving single user system interface requirements. This work extends this method by
introducing analytic steps to identify task and decision-making dependencies between different
UAV operations collaborators.
This collaborative extension to the Hybrid CTA utilizes the notion of boundary objects, an
analytic construct commonly used in the study of group work. Boundary objects are physical or
information artifacts that cross the task boundaries between members of distinct groups.
Identifying boundary objects in complex task operations help the analyst to identify task and
decision-making dependencies between local and remote collaborators. Understanding these
dependencies helps to identify information sharing requirements that the UAV system should
support.
This report describes the analytic steps of the collaborative extension, and provides background
information on the original Hybrid CTA method and the boundary object construct. The report
also describes a project in which the new design requirements method was used to revise a
proposed set of UAV operator displays.Prepared For Boeing Phantom Work
Performance of the sleep-mode mechanism of the new IEEE 802.16m proposal for correlated downlink traffic
There is a considerable interest nowadays in making wireless telecommunication more energy-efficient. The sleep-mode mechanism in WiMAX (IEEE 802.16e) is one of such energy saving measures. Recently, Samsung proposed some modifications on the sleep-mode mechanism, scheduled to appear in the forthcoming IEEE 802.16m standard, aimed at minimizing the signaling overhead. In this work, we present a performance analysis of this proposal and clarify the differences with the standard mechanism included in IEEE 802.16e. We also propose some special algorithms aimed at reducing the computational complexity of the analysis
Performance of the IEEE 802.16e sleep mode mechanism in the presence of bidirectional traffic
We refine existing performance studies of the WiMAX sleep mode operation to take into account uplink as well as downlink traffic. This as opposed to previous studies which neglected the influence of uplink traffic. We obtain numerically efficient procedures to compute both delay and energy efficiency characteristics. A test scenario with an Individual Subscriber Internet traffic model in both directions shows that even a small amount of uplink traffic has a profound effect on the system performance
Mobile computing & law enforcement: An Examination of its application in the field and its consequences
The following study has been conducted in the pursuit of a Masters Degree of Science in Information Technology. The functional purpose of this study was to examine three basic concepts (officer efficiency, safety, and arrest rates) within law enforcement and to attempt to determine if a specific type of information technology (wireless data computers) has had any positive impact on those concepts. To that end, the author has reviewed the history of technology in law enforcement and surveyed a group of patrol officers in the Wilmington Police Department. Difficulties associated with gathering research data from law enforcement agencies has also been noted and described. The results garnered from statistical analysis are covered in detail
Regenerable Antibacterial Cotton Fabric by Plasma Treatment with Dimethylhydantoin: Antibacterial Activity against S. aureus
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The development of an embedded wireless modem conforming to advanced mobile phone system and cellular digital packet data standards
Introduced by AT&T Bell Labs in 1970s, today Advanced Mobile Phone Systems (AMPS) - a first generation analog cellular system serve millions of customers in the United States and 55 other countries, and the number of subscribers is still rapidly increasing. Although digital cellular systems are emerging in recent years, research efforts are still being made to the enhancement of AMPS systems because of their popularity. An example is the new Cellular Digital Packet Data (CDPD) standard announced in 1994. CDPD is an overlay of the existing AMPS, and has the capability of transmitting data packets over such an analog cellular network. This thesis intends to first introduce this new technology, and then discusses the design and implementation of an embedded wireless modem which conforms to the CDPD public standard. The emphasis is on software design, implementation, simulation, and test of the modem. The real-time test and demonstration shows that the newly developed modem and related software meet the requirements and specifications in terms of functionality, modularity, robustness, and low power consumption
A Tutorial on Cross-layer Optimization Wireless Network System Using TOPSIS Method
Each other, leading to issues such as interference, limited bandwidth, and varying channel conditions. These challenges require specialized optimization techniques tailored to the wireless environment. In wireless communication networks is to maximize the overall system throughput while ensuring fairness among users and maintaining quality of service requirements. This objective can be achieved through resource allocation optimization, where the available network resources such as bandwidth, power, and time slots are allocated to users in an optimal manner. Optimization-based approaches in wireless resource allocation typically involve formulating the resource allocation problem as an optimization problem with certain constraints.. These techniques provide practical solutions with reduced computational complexity, although they may not guarantee optimality. In summary, optimization-based approaches have been instrumental in studying resource allocation problems in communication networks, including the wireless domain. While techniques from the Internet setting have influenced the understanding of congestion control and protocol design, specific challenges in wireless networks necessitate tailored optimization techniques that account for interference, limited bandwidth, and varying channel conditions. power allocation problem in wireless ad hoc networks Cross-layer optimization refers to the process of jointly optimizing the allocation of resources across different layers of wireless networks, the interactions between different layers become more complex due to the shared medium and time-varying channel conditions. Nash equilibrium, where no user can unilaterally improve its own performance by changing its strategy. Game theory can capture the distributed nature of wireless networks and provide insights into the behavior of users in resource allocation scenarios Additionally, heuristics and approximation algorithms are often employed in wireless resource allocation due to the complexity of the optimization problems involved. In traditional cellular systems, each user is allocated a fixed time slot for transmission, regardless of their channel conditions. However, in opportunistic scheduling. Alternative parameters for “Data rate Ž kbps, Geographic coverage , Service requirements , cost ” Evaluation parameter for “Circuit-switched cell, CDPD, WLAN, Paging, Satellite.” “the first ranking training is obtained with the lowest quality of compensation.
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