128 research outputs found
Multibeam Network Design and Measurement for Triangular Array of Three Radiating Elements
Nowadays, more a more base stations are equipped with active conformal antennas. These antenna designs combine phase shift systems with multibeam networks providing multi-beam ability and interference rejection, which optimize multiple channel systems. GEODA is a conformal adaptive antenna system designed for satellite communications. Operating at 1.7 GHz with circular polarization, it is possible to track and communicate with several satellites at once thanks to its adaptive beam. The antenna is based on a set of similar triangular arrays that are divided in subarrays of three elements called `cells'. Transmission/Receiver (T/R) modules manage beam steering by shifting the phases. A more accurate steering of the antenna GEODA could be achieved by using a multibeam network. Several multibeam network designs based on Butler network will be presente
3x3 Multibeam Network for a Triangular Array of Three Radiating Elements
A multibeam antenna study based on Butler network will be undertaken in this document. These antenna designs combines phase shift systems with multibeam networks to optimize multiple channel systems. The system will work at 1.7 GHz with circular polarization. Specifically, result simulations and measurements of 3 element triangular subarray will be shown. A 45 element triangular array will be formed by the subarrays. Using triangular subarrays, side lobes and crossing points are reduced
6x3 Microstrip Beam Forming Network for Multibeam Triangular Array
A six inputs and three outputs structure which can be used to obtain six simultaneous beams with a triangular array of 3 elements is presented. The beam forming network is obtained combining balanced and unbalanced hybrid couplers and allows to obtain six main beams with sixty degrees of separation in azimuth direction. Simulations and measurements showing the performance of the array and other detailed results are presente
Understanding the Success of Government Portals: The Role of Political Leadership, Standards, and a Powerful Centralized IT Agency
Information technologies have become an essential component of government administrative reforms and governance strategies around the world. Although Internet portals are now some of the most mature technologies, they continue to be the most important channel for governments to provide information and services to citizens and other stakeholders. However, studies about government portals still lack the level of detail necessary to better understand the specific variables that affect their success and, more prominently, how these variables intertwine. Based on institutional theory, particularly the technology enactment framework, and one in-depth case study in Mexico, this paper shows how leadership from the governor, the establishment of government-wide rules and standards, and the existence of a powerful centralized IT agency collectively affect the process of enacting a state government website and its potential results. The paper also identifies other variables and discusses some of their interactions and mechanisms of influence
Providing Public Value through Data Sharing: Understanding Critical Factors of Food Traceability for Local Farms and Institutional Buyers
Many of the datasets that could contribute to solutions for current public problems are proprietary and reside outside of government agencies. Accelerating data sharing and collaboration between those who hold valuable data and those able to deliver solutions is key to generating public value from private data. There is still a limited body of literature, however, that addresses data sharing and collaboration between private and public organizations. Using a case study of food traceability from local farms to institutions, this paper contributes to this emerging field by identifying challenges and incentives in data sharing among different types of organizations. In particular, our goal is to study how small farms and institutional buyers can be incentivized to share their data in a way that contributes to food safety, public health, and other societal goals. Our findings demonstrate that initiatives which can show the benefits of having a whole-chain food traceability system, have clear policies and regulations, and opportunities for participation in training activities are key incentives
Public Libraries’ Perceptions of Future Collaborations for the Development of Smart Cities and Communities: Understanding Influential Factors
Recently, the concept of smart city has been adopted by many communities as a strategy to find alternative solutions to increasingly complex social, economic, and environmental issues. Different local actors, including public libraries, are already playing an important role in developing smart cities and communities either by themselves or in collaboration with other organizations. However, most public libraries are not currently collaborating for smart community development. Therefore, this paper analyzes the factors that influence public libraries’ perceptions about future collaborations in developing smart cities and communities as well as their potential benefits. The results show that consequential incentives, the nature of the task, preexisting relationships, an agreement on initial aims, and a collaborative and supportive leader all have a significant positive impact on the extent, effectiveness, and benefits of public libraries’ future collaborations to develop smart cities and communities
Study of an electronic steering antenna with a staggered phase shifter configuration
This paper presents a study of three possible solutions that can be taken into account to control the phase shift between elements in an antenna array. Because commercial digital phase shifters have become a strategic element by U.S. Government, these elements have increased their price. For this reason, it is necessary to adopt some solutions that allow us to deal with the design and construction of antenna arrays
Public Libraries as Anchor Institutions in Smart Communities: Current Practices and Future Development
Local governments around the world are exploring different strategies to become smarter: more efficient, sustainable, and highly interconnected. However, many actors outside government need to be involved too. For instance, public libraries have the potential to play a very important role in the development of smart and connected communities, due to their strong legitimacy in the eyes of citizens and the types of services and programs they are already providing, which in many cases go well beyond what could be considered traditional library services. This paper analyzes innovative practices in public libraries and argue that they already show the potential of public libraries to become catalysts for smart and connected communities. Together, these innovations represent an opportunity for governments and communities to engage and a new way to think about public libraries as very important actors in smart community initiatives
Red Multihaz de Desfase Escalonado para el Control de un Array de Antenas.
This paper presents a general systems that can be taken into account to control between elements in an antenna array. Because the digital phase shifter devices have become a strategic element and also some steps have been taken for their export by U.S. Government, this element has increased its price to the low supply in the market. Therefore, it is necessary to adopt some solutions that allow us to deal with the design and construction of antenna arrays. system based on a group of a staggered phase shift with external switching is shown, which is extrapolated array
The normalized difference vegetation index (NDVI) as indicator of the soil degradation.
In this work we presenl lhe lemporal evolulion 01 lhe vegelalion and Iheir relalionship wilh lhe soil degradalion in an area loealed in Northeasl 01 lhe Madrid Communily (Spain)
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