Optimal Resource Allocation and Relay Selection in Bandwidth Exchange Based Cooperative Forwarding

In this paper, we investigate joint optimal relay selection and resource allocation under bandwidth exchange (BE) enabled incentivized cooperative forwarding in wireless networks. We consider an autonomous network where N nodes transmit data in the uplink to an access point (AP) / base station (BS). We consider the scenario where each node gets an initial amount (equal, optimal based on direct path or arbitrary) of bandwidth, and uses this bandwidth as a flexible incentive for two hop relaying. We focus on alpha-fair network utility maximization (NUM) and outage reduction in this environment. Our contribution is two-fold. First, we propose an incentivized forwarding based resource allocation algorithm which maximizes the global utility while preserving the initial utility of each cooperative node. Second, defining the link weight of each relay pair as the utility gain due to cooperation (over noncooperation), we show that the optimal relay selection in alpha-fair NUM reduces to the maximum weighted matching (MWM) problem in a non-bipartite graph. Numerical results show that the proposed algorithms provide 20- 25% gain in spectral efficiency and 90-98% reduction in outage probability.Comment: 8 pages, 7 figure

Data Collection on Sensitive Topics with Adolescents Using Interactive Voice Response Technology

We describe the development and implementation of a survey administered using interactivevoice response (IVR) technology to collect information on sensitive topics in a USnational sample of adolescents age 12-17. Respondents were participants in the Panel Study of Income Dynamics 2014 Child Development Supplement (N=1,098). We review questionnaire design, fieldwork protocols, data quality and completeness, and respondent burden. We find that in the context of research on sensitive topics with adolescents, IVR is a cost-efficient and flexible method of data collection that yields high survey response rates and low item nonresponse rates with distributions on key variables that are comparable to other national studies

Implementation of Distributed Time Exchange Based Cooperative Forwarding

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

Assessing the Opportunities and Challenges in the Transition to Computer-Based Survey Data Collection: The Role of Key Software System Features

This report examines the opportunities and challenges associated with the adoption of computer-assisted interviewing (CAI) technology for data collection in household surveys in the Indian context, following a recent large-scale test of CAI in the southern Indian state of Tamil Nadu. The issues identified are highly relevant to the Government of Tamil Nadu’s (GOTN) ongoing work to convert state survey data collection operations to CAI. These issues are also more generally informative to the shift from paper-based questionnaire instruments to CAI technology for state governments throughout India. The Survey Research Center (SRC) at the University of Michigan has worked closely with a Tamil Nadu state government agency—the Department of Economics and Statistics—that is at the center of this shift to CAI. Based on this experience, and our background running major CAI surveys in the U.S., Nepal, China, and elsewhere, this report provides some broader context about CAI, key features to consider in the selection of CAI software platforms, issues in the management of CAI operations, and related topics. This report was prepared by SRC independently of GOTN, but in service of the GOTN’s work to expand CAI data collection.World Bankhttp://deepblue.lib.umich.edu/bitstream/2027.42/171096/1/WB Report Transition to CAPI FINAL 2021-02-27.pdfDescription of WB Report Transition to CAPI FINAL 2021-02-27.pdf : Technical ReportSEL

Cox-McFadden Partial and Marginal Likelihoods for the Proportional Hazard Model with Random Effects

In survival analysis, Cox\u27s name is associated with the partial likelihood technique that allows consistent estimation of proportional hazard scale parameters without specifying a duration dependence baseline. In discrete choice analysis, McFadden\u27s name is associated with the generalized extreme-value (GEV) class of logistic choice models that relax the independence of irrelevant alternatives assumption. This paper shows that the mixed class of proportional hazard specifications allowing consistent estimation of scale and mixing parameters using partial likelihood is isomorphic to the GEV class. Independent censoring is allowed and I discuss approximations to the partial likelihood in the presence of ties. Finally, the partial likelihood score vector can be used to construct log-rank tests that do not require the independence of observations involved