Temporal Behavior of the Individual Soft Microparticles: Understanding the Detection by Particle Impact Electrochemistry

Emerging progress of the Particle Impact Electrochemistry (PIE) technique has opened a novel field of detection and characterization of many analyte particles. 1 PIE comprises detection of changes in current when collisions of individual micro or nanoparticles are linked with an electrochemical event at the surface of an ultramicroelectrode (UME). 2 Being a rapid, low cost, and analyzing of one analyte at a time, PIE is widely used to characterize the shape, size distribution, and catalytic activity of nanoparticles. 2-5 To explore the scope of PIE for the detection of soft microparticles (absence of crystalline structure), ferrocene (Fc) trapped toluene-in-water emulsion droplets was used as a model with ultramicroelectrode. Droplets were analyzed by tracking the oxidation of Fc inside the droplet in the presence of an ionic liquid acting as emulsifier and conductivity enhancer. The droplet diameter was determined electrochemically using Faraday’s law. PIE was able to characterize the polydisperse size distribution of the droplets successfully. A 3D lattice random walk simulation indicated the stochastic nature of the droplet motion. Unlike nanoparticles, the droplets have slow kinetics and the collision dynamics associated with adsorption on the electrode surface. The adsorbing droplet generated similar spike-like electrical signals in real-time experiments that follow the bulk electrolysis model. These findings will facilitate the characterization of polydisperse microparticles including bacteria, which also adsorb and have similar size and density as the droplets in this work. Finally, because electrolysis time spans from hundreds of milliseconds to a second, single events of such duration are detectable with present-day instrumentation in contrast to non-adsorbing nanoparticles that have nanosecond collisions.https://scholarscompass.vcu.edu/gradposters/1057/thumbnail.jp

Building Programmable Wireless Networks: An Architectural Survey

In recent times, there have been a lot of efforts for improving the ossified Internet architecture in a bid to sustain unstinted growth and innovation. A major reason for the perceived architectural ossification is the lack of ability to program the network as a system. This situation has resulted partly from historical decisions in the original Internet design which emphasized decentralized network operations through co-located data and control planes on each network device. The situation for wireless networks is no different resulting in a lot of complexity and a plethora of largely incompatible wireless technologies. The emergence of "programmable wireless networks", that allow greater flexibility, ease of management and configurability, is a step in the right direction to overcome the aforementioned shortcomings of the wireless networks. In this paper, we provide a broad overview of the architectures proposed in literature for building programmable wireless networks focusing primarily on three popular techniques, i.e., software defined networks, cognitive radio networks, and virtualized networks. This survey is a self-contained tutorial on these techniques and its applications. We also discuss the opportunities and challenges in building next-generation programmable wireless networks and identify open research issues and future research directions.Comment: 19 page

Estimation of willingness to pay for improvement in dirnking water quality: a study of wasa, lahore

This study examines the existing water quality of Lahore and measures domestic household's willingness to pay for improvement in water quality services. To this end, a Tobit model is estimated by conducting a contingent valuation survey about household perceptions in six towns of Lahore. The results show that the factors affecting household's willingness to pay are coping costs that a household pay for ensuring quality of water.The study also finds the education level of head of family is an important factor in determining the willingness to pay for improved water services. It is recommended that by ensuring the supply and quality to the household additional revenue of 4.22 million rupees could be earned by the authority.Willingness to Pay, Tobit, Drinking Water Quality

Do migrant remittances matter? Nature, determinants and impacts of remittances to Pakistan

Diese Arbeit ist eine Sammlung von Studien, welche sowohl die makro-, als auch die mikroökonomischen Aspekte und Charakteristika von Rücküberweisungen pakistanischer Migranten in ihr Heimatland analysieren, sowie deren ökonomische Auswirkungen auf das Konsumverhalten und die Vermögensbildung der Empfängerhaushalte. Es zeigt sich, dass internationale Überweisungen im Vergleich zu anderen finanziellen Mittelflüssen eine stabile und stabilisierende Quelle für Devisen darstellen. Des Weiteren weisen sie mit Blick auf die heimische Wirtschaft ein antizyklisches Verhalten auf, während ihr Verhalten mit Blick auf die Wirtschaft des Gastlandes als azyklisch beschrieben werden kann.  Die Überweisungsströme werden maßgeblich von ihren Transaktionskosten beeinflusst, so dass Migranten in Zeiten hoher Transaktionskosten Rücküberweisungen ins Heimatland entweder einstellen oder informelle Kanäle zum Überweisen nutzen. Im Rahmen dieser Studie stellt sich außerdem heraus, dass Rücküberweisungen als hauptsächlich kurzfristige Einnahmequelle betrachtet werden. Aufgrund dessen werden die Zuflüsse oftmals in die Förderung von Humankapital investiert, wobei dieser Effekt stark abhängig vom Einkommensniveau des Empfängeraushalts ist.  Ferner führen internationale Überweisungen zu einem erheblichen Anstieg des Haushaltsvermögens, wohingegen Inlandsübweisungen keine signifikanten Vermögensänderungen mit sich bringen. Überdies ermöglichen internationale Rücküberweisungen den Empfängerhaushalten das Aufstocken vorsorglicher Ersparnisse.

What is Hidden, in the Hidden Economy of Pakistan? Size, Causes, Issues and Implications

There is a worldwide contemporary debate about the role of the hidden economy in achieving the goal of sustained and inclusive economic growth and development, especially in the context of its spillover effects on the formal economy. For this purpose, policy makers and academicians have made concerted efforts to estimate the size of the hidden economy and to analyze its causes, issues and implications on key macroeconomic variables. However, there is a consensus among the policy makers that a better macroeconomic policy formulation and its true implementation are subject to the proper management of the associated issues of the hidden economy with suitable policy measures. In Pakistan, it is generally assumed that the hidden economy contributes about 30% to 50% to the overall GDP. The purpose of this paper is to estimate more precisely the size of the hidden economy with the determination of its potential causes and implications. Five statistical and structural modeling approaches namely; simple monetary approach, modified monetary approach using dynamic ordinary least square (DOLS), multiple-indicators multiple-causes (MIMIC) approach, electricity consumption approach and labor market survey based approach are used to estimate the size of the hidden economy and to analyze the characteristic nature of its growth over the period. The study also investigates the potential determinants of the hidden economy and various interrelated socio-economic issues in perspective of achieving national goal of inclusive growth and development. Finally, policy implications are provided consistent with pervading facts of the hidden economy in Pakistan especially in the context of the 18th Amendment and the 7th NFC Award.Hidden Economy, Size, Causes, Socio-Economic Implications, Inclusive Growth and Development, 18th Amendment and 7th NFC Award of Pakistan

The Graduating Class

An unprecedented number of seniors are graduating with an Economics degree this year. The seniors are planning on getting into a number of different areas following their graduation. Here is a brief description of each senior

Offloading Content with Self-organizing Mobile Fogs

Mobile users in an urban environment access content on the internet from different locations. It is challenging for the current service providers to cope with the increasing content demand from a large number of collocated mobile users. In-network caching to offload content at nodes closer to users alleviate the issue, though efficient cache management is required to find out who should cache what, when and where in an urban environment, given nodes limited computing, communication and caching resources. To address this, we first define a novel relation between content popularity and availability in the network and investigate a node's eligibility to cache content based on its urban reachability. We then allow nodes to self-organize into mobile fogs to increase the distributed cache and maximize content availability in a cost-effective manner. However, to cater rational nodes, we propose a coalition game for the nodes to offer a maximum "virtual cache" assuming a monetary reward is paid to them by the service/content provider. Nodes are allowed to merge into different spatio-temporal coalitions in order to increase the distributed cache size at the network edge. Results obtained through simulations using realistic urban mobility trace validate the performance of our caching system showing a ratio of 60-85% of cache hits compared to the 30-40% obtained by the existing schemes and 10% in case of no coalition

A Content-based Centrality Metric for Collaborative Caching in Information-Centric Fogs

Information-Centric Fog Computing enables a multitude of nodes near the end-users to provide storage, communication, and computing, rather than in the cloud. In a fog network, nodes connect with each other directly to get content locally whenever possible. As the topology of the network directly influences the nodes' connectivity, there has been some work to compute the graph centrality of each node within that network topology. The centrality is then used to distinguish nodes in the fog network, or to prioritize some nodes over others to participate in the caching fog. We argue that, for an Information-Centric Fog Computing approach, graph centrality is not an appropriate metric. Indeed, a node with low connectivity that caches a lot of content may provide a very valuable role in the network. To capture this, we introduce acontent-based centrality (CBC) metric which takes into account how well a node is connected to the content the network is delivering, rather than to the other nodes in the network. To illustrate the validity of considering content-based centrality, we use this new metric for a collaborative caching algorithm. We compare the performance of the proposed collaborative caching with typical centrality based, non-centrality based, and non-collaborative caching mechanisms. Our simulation implements CBC on three instances of large scale realistic network topology comprising 2,896 nodes with three content replication levels. Results shows that CBC outperforms benchmark caching schemes and yields a roughly 3x improvement for the average cache hit rate