Evaluation of Network Mobility Schemes for Terrestrial and Satellite Networks

NEtwork MObility (NEMO) supports the mobility of multiple Internet-connected devices. However, NEMO Basic Support Protocol suffers from unoptimized route leading to large latency in communication and header overhead. To optimize route, a plethora of schemes have been proposed. These schemes differ in terms of several performance parameters, such as signaling, end-to-end delay andhandoff latency. However, no performance or cost evaluation exists in the literature to compare the schemes. In addition, mobility management is required to support the mobility of Internet-connected devices in satellite networks. Existing mobility management solutions for satellite networks are unable toprovide connectivity to the Internet when satellites are not directly connected to the ground.In this dissertation, a comprehensive evaluation of the schemes and a mobility management solution for satellite networks using NEMO are provided. The schemes are classified and compared to choose the optimal class. Using analytical and simulation-based models, the schemes in the chosen class are compared based on the performance parameters. The effect of the parameters on transmission Control Protocol, the dominant transport protocol in the Internet, is also evaluated. A cost evaluation is performed to determine the network resource consumption of the schemes. Finally, an architecture and extensions of the basic protocol are presented to apply NEMO in satellite networks. This dissertation fosters the application of NEMO to terrestrial and satellitenetworks by selecting and extending optimal route optimization schemes, and presenting new architecture and protocol

Essays in microfinance

This dissertation includes three essays in microfinance. Using primary data from Bangladesh, the first essay examines the role of bank-borrower relationships in the application and approval of microcredit. The empirical findings suggest that the likelihood of applying, and being approved, for microcredit increases as the length of membership with a microfinance institution (MFI) increases. Those who have taken loans from the same MFI before are more likely to apply for new loans; and those who have maintained a non-mandatory savings account are more likely to apply and be approved for microcredit. Having relationships with multiple lenders reduces the probability of being approved for a loan. Furthermore, it is the large (rather than small) MFIs that rely more on relationship metrics. The findings complement the intuition provided in the theoretical in that, in addition to joint liability, MFIs substantially rely on relationship driven information in extending loans. The second essay examines whether the likelihood of forming heterogeneous borrowing groups increases in microcredit when borrowers are able to transfer resources among themselves for purposes of risk sharing. Based on evidence from framed field experiments in Bangladesh, the study shows that risky borrowers are willing to offer side payments, as insurance premium, which can attract safe borrowers to form heterogeneous borrowing groups. However, existence of a strong social tie among the potential borrowing partners is necessary for the emergence of heterogeneous groups in microcredit. The third easy uses primary data from Bangladesh to examine whether bank-borrower relationships affect the process of transition from joint liability to individual liability loans in microcredit. Using instrumental variables in survival analysis, it shows that borrowers, who maintain a non-mandatory savings account with the MFI, and those who borrow from a single MFI, graduate from joint to individual liability loans with relatively short repayment records. The results are robust across a range of non-parametric and parametric specifications. The findings imply that MFIs have incentives to invest in relationship development in order to expedite the process of transition from joint to individual liability loans, which in turn, can reduce the incidence of voluntary drop outs by the matured borrowers

Relationship Lending in Microcredit: Evidence from Bangladesh

We use primary data compiled from the field in 34 randomly selected villages in Bangladesh to examine the role of bank-borrower relationships in the application and approval stages of microcredit. We find evidence that potential borrowers who have maintained membership for a long time, and who have non-mandatory saving accounts and a successful track record of previous loans are more likely to apply, and be approved, for individual as well as group loans. Having a relationship with multiple lenders increases the probability of applying for a loan but reduces the probability of being approved for it. We also provide evidence that it is the large (rather than small) microfinance institutions who rely more on relationship metrics.Microcredit, relationships, credit constraint, adverse selection, peer monitoring

Performance of Prefix Delegation-Based Route Optimization Schemes: Intra Mobile Network case

Among the route optimization schemes in NEtwork MObility (NEMO), the prefix delegation-based schemes perform better than other schemes. Since the prefix delegation-based schemes are designed for communication between a mobile network and a wired network, they lack evaluation for the case of intra mobile network communication involving MIPv6 incapable hosts in a mobile network. We evaluate prefix delegation-based schemes to reveal their inefficiencies for the case where both the communicating hosts are mobile and MIPv6 incapable, propose extensions, and compare them. Since both the communicating hosts are mobile, handoff latency in extended schemes are large resulting in significant performance loss when the speed of the mobile network is high. Results reveal that the effect of speed of the mobile network dominates the performance in such cases. We conclude that for slow moving mobile networks, extended schemes are preferable

Route Optimization in Network Mobility: Solutions, Classification, Comparison, and Future Research Directions

NEtwork MObility (NEMO) handles mobility of a set of mobile nodes in an aggregate way using one or more mobile routers. NEMO introduces several advantages, such as reduced signaling, increased manageability, reduced power consumption and conservation of bandwidth when compared to individual host mobility. NEMO Basic Support Protocol (BSP), the IETF standard for NEMO, suffers from a number of limitations, like inefficient route and increased handoff latency. Most of the recent research efforts on NEMO have concentrated on solving the problem of inefficient route resulting in several route optimization schemes to solve the problem. To choose a route optimization scheme, it is very important to have a quantitative comparison of the available route optimization schemes. The objective of this article is to survey, classify and compare the route optimization schemes proposed in the literature over the last five years. We classify the schemes based on the basic approach for route optimization, and compare the schemes based on protocol overhead, such as header overhead, amount of signalling, and memory requirements. We conclude that performance of the classes of schemes has to be evaluated under criteria such as available bandwidth, topology of the mobile network and mobility type

Reaching out to the unbanked: The role of political ideology in financial inclusion

This paper studies the effect of political ideology on household financial inclusion. Financial inclusion is the access to formal financial services and provides an entry key for people to participate in the economy. Using granular data of 65 countries, we find that financial inclusion is higher under right-wing regimes than under left-wing governments. We use regression discontinuity design and propensity-score matching to address endogeneity issues. We investigate multiple channels for the effect and conclude that right-wing market-oriented policies are more successful in enhancing financial inclusion than left-wing societal policies