14,887 research outputs found

    BIO-ECONOMIC DEVELOPMENT OF FLOODPLAINS: FARMING VERSUS FISHING IN BANGLADESH

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    This paper explores the linkages of environment and economic development in the floodplain of large rivers. There is considerable evidence that even the most vital floodplains in the world are not being managed efficiently and both economic and ecological factors need to be considered for effective management. Floodplain management policies in Bangladesh emphasize structural changes to enhance agricultural production. However, these structural changes reduce fisheries production, where the fishery is an important natural resource sector and a source of subsistence for the rural poor. We develop a model where net returns to agriculture and fisheries are jointly maximized taking into account the effect of flooding depth and timing on production. Results for a region in Bangladesh show that optimal production in a natural floodplain yields higher net returns compared to a floodplain modified by flood control structures. This finding has important implications for management policies -- neglecting the bio-economic relationship between fisheries and land use may significantly affect the long-run economic role of a river floodplain, particularly in a poor country.Community/Rural/Urban Development,

    Behavioural markers: bridging the gap between art of analysis and science of analytics in criminal intelligence

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    Studying how intelligence analysts use interaction in visualization systems is an important part of evaluating how well these interactions support analysis needs, like generating insights or performing tasks. Intelligence analysis is inherently a fluid activity involving transitions between mental and interaction states through analytic processes. A gap exists to complement these transitions at micro-analytic level during data exploration or task performance. We propose Behavioural markers (BMs) which are representatives of the action choices that analysts make during their analytical processes as the bridge between human cognition and computation through semantic interaction. A low level semantic action sequence computation technique has been proposed to extract these BMs from captured process log. Our proposed computational technique can supplement the problems of existing qualitative approaches to extract such BMs

    Rate Optimal design of a Wireless Backhaul Network using TV White Space

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    The penetration of wireless broadband services in remote areas has primarily been limited due to the lack of economic incentives that service providers encounter in sparsely populated areas. Besides, wireless backhaul links like satellite and microwave are either expensive or require strict line of sight communication making them unattractive. TV white space channels with their desirable radio propagation characteristics can provide an excellent alternative for engineering backhaul networks in areas that lack abundant infrastructure. Specifically, TV white space channels can provide "free wireless backhaul pipes" to transport aggregated traffic from broadband sources to fiber access points. In this paper, we investigate the feasibility of multi-hop wireless backhaul in the available white space channels by using noncontiguous Orthogonal Frequency Division Multiple Access (NC-OFDMA) transmissions between fixed backhaul towers. Specifically, we consider joint power control, scheduling and routing strategies to maximize the minimum rate across broadband towers in the network. Depending on the population density and traffic demands of the location under consideration, we discuss the suitable choice of cell size for the backhaul network. Using the example of available TV white space channels in Wichita, Kansas (a small city located in central USA), we provide illustrative numerical examples for designing such wireless backhaul network

    Average spectral properties of galactic X-ray binaries with 3 years of MAXI data

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    The energy spectra of X-ray binaries (XRBs) have been investigated during the last few decades with many observatories in different energy bands and with different energy resolutions. However, these studies are carried out in selected states of XRBs like during outbursts, transitions, quiescent states, and are always done in limited time windows of pointed observations. It is now possible to investigate the long term averaged spectra of a large number of X-ray binaries with the all sky monitor MAXI, which also has a broad energy band. Here we present the average spectral behaviour of a few representative XRBs. The long term averaged spectrum of Cyg X-1 is described by a sum of two power-laws having Γ1\Gamma_{1} ~ 2.8 and Γ2\Gamma_{2} ~ 1.2, along with a multi color disk blackbody having an inner disk temperature of 0.5 keV, GX 301-2 is described by a power-law with a high energy cut-off at EcE_{c} ~ 15 keV and a blackbody component at 0.2 keV and that of Aql X-1 is described by a multi color disk blackbody at 2 keV and a power-law of Γ\Gamma ~ 2.2. We have also constructed the combined X-ray spectrum of the X-ray binaries in the Milky Way, which can be compared to the XRBs spectra of other galaxies observed with Chandra and XMM-Newton. These measurements are also relevant to investigate the X-ray interaction with the ISM and its contribution to the ionising X-ray background in the early universe.Comment: To be published in ASI Conference Series on "Recent Trends in the Study of Compact Objects: Theory and Observation

    Implementation of Distributed Time Exchange Based Cooperative Forwarding

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    In this paper, we design and implement time exchange (TE) based cooperative forwarding where nodes use transmission time slots as incentives for relaying. We focus on distributed joint time slot exchange and relay selection in the sum goodput maximization of the overall network. We formulate the design objective as a mixed integer nonlinear programming (MINLP) problem and provide a polynomial time distributed solution of the MINLP. We implement the designed algorithm in the software defined radio enabled USRP nodes of the ORBIT indoor wireless testbed. The ORBIT grid is used as a global control plane for exchange of control information between the USRP nodes. Experimental results suggest that TE can significantly increase the sum goodput of the network. We also demonstrate the performance of a goodput optimization algorithm that is proportionally fair.Comment: Accepted in 2012 Military Communications Conferenc
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