Analysis of a Collaborative Filter Based on Popularity Amongst Neighbors

In this paper, we analyze a collaborative filter that answers the simple question: What is popular amongst your friends? While this basic principle seems to be prevalent in many practical implementations, there does not appear to be much theoretical analysis of its performance. In this paper, we partly fill this gap. While recent works on this topic, such as the low-rank matrix completion literature, consider the probability of error in recovering the entire rating matrix, we consider probability of an error in an individual recommendation (bit error rate (BER)). For a mathematical model introduced in [1],[2], we identify three regimes of operation for our algorithm (named Popularity Amongst Friends (PAF)) in the limit as the matrix size grows to infinity. In a regime characterized by large number of samples and small degrees of freedom (defined precisely for the model in the paper), the asymptotic BER is zero; in a regime characterized by large number of samples and large degrees of freedom, the asymptotic BER is bounded away from 0 and 1/2 (and is identified exactly except for a special case); and in a regime characterized by a small number of samples, the algorithm fails. We also present numerical results for the MovieLens and Netflix datasets. We discuss the empirical performance in light of our theoretical results and compare with an approach based on low-rank matrix completion.Comment: 47 pages. Submitted to IEEE Transactions on Information Theory (revised in July 2011). A shorter version would be presented at ISIT 201

Allocation of Advertisement Extensions & Formats

This document describes a process of optimizing the selection of a budget-constrained advertiser\u27s formats when allocating the budget of a budget-constrained advertiser. Such optimization is performed by selectively choosing which formats to allocate to this advertiser based on the advertiser\u27s budget. In particular, this document describes allocating formats to budget-constrained advertisers in advertising auctions to create value for the advertisers and an advertiser manager

Global Dynamics of Online Group Conversations

Public online groups allow individuals to carry out conver- sations of common interests. Study of such group conversa- tions provides a unique opportunity to study patterns of hu- man conversations without violating individual privacy. The observational studies conducted in this paper are an attempt to identify the main correlates of continued growth of con- versations, thereby clearing the path to developing predictive models user participation. We study temporal evolution of online group discussions. Surprisingly, we find that individual discussion groups dis- play distinctively q-exponential shaped inter-message times to reply distributions, unlike the power law distributions seen in email conversations. We show, using simulations, that the heavy-tailed distribution of time to reply, which we also ob- serve when all data is combined, originate from mixtures of q-exponentials. We also find that popular threads come to be so from the very beginning as opposed to evolving to be more popular as they grow. This raises new possibilities for devel- oping generative models of thread growth

A note on linear function approximation using random projections

Linear function approximations based on random projections are proposed and justified for a class of fixed point and minimization problems

EFFECTS OF COVID-19 ON FISHERIES PRODUCTS EXPORTED FROM SOUTHWEST BANGLADESH: A CASE STUDY

The COVID-19 pandemic has posed unprecedented challenges for fisheries products export, which serves as a major export driver and employment for the people of Bangladesh. The countrywide lockdown has severely disrupted the supply chain; and port closures and international cargo restrictions have threatened export markets. To unpack the COVID impacts, the detailed fisheries products export-oriented primary data of 45 fish processing plants were collected from Fish Inspection and Quality Control (FIQC), Khulna between January 2020 and December 2021. Ten key informant interviews were conducted with Upazila Fisheries Officer, FIQC personnel and stakeholders of fish processing plants to know the official export data during the pandemic periods. This was followed by further focus group discussions on fish processing plant employees to assess the real impact of COVID-19 on the export of fisheries products in Southwest Bangladesh. In this paper, our study clearly shows that the COVID-19 has resulted in a squeeze export volume of fisheries products during the first wave of Covid-19 from March to May 2020. By 2020, it was observed that the amounts of exported products were somewhat stable, however the unit price (US$/MT) continued to decline. Moreover, the export market improved slightly in 2021 and the unit price of export products continued to rise. We also found some other adverse effects of COVID-19 such as delay in product shipment, increased cost of packing materials, purchase order cancelation from buyers, shortage and the increased price of raw materials, complete shutdown of few processing plants, increased transportation cost, shortage of containers, employee lay off from the company, etc. To meet these challenges, the government must take necessary measures to address this vulnerable sector and formulate appropriate policies to minimize the adverse effects of such uncertainties in the future. [J Bangladesh Agril Univ 2022; 20(2.000): 217-224

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Not AvailableSubsurface drainage (SSD) has been proved to be an effective technology to reclaim waterlogged saline soils. Three SSD projects were implemented in Haryana, India in 2009, 2012 and 2016 to study the long term effect of SSD (10, 7 and 3 years) operation on restoring productivity and carbon sequestration potential of degraded waterlogged saline soils under prevalent rice-wheat cropping system. These studies indicated that successful operation of SSD improved soil quality parameters such as bulk density, BD (from 1.58 to 1.52 Mg m−3), saturated hydraulic conductivity, SHC (from 3.19 to 5.07 cm day−1); electrical conductivity, ECe (from 9.72 to 2.18 dS m−1), soil organic carbon, OC (from 0.22 to 0.34 %), dehydrogenase activity, DHA (from 15.44 to 31.65 μg g−1 24 h−1), and alkaline phosphatase, ALPA (from 16.66 to 40.11 μg P-NP g−1 h−1) in upper soil surface (0–30 cm). The improved soil quality resulted in increased rice-wheat system yield (rice equivalent yield) by 328 %, 465 % and 665 % at Kahni, Siwana Mal and Jagsi sites, respectively. Studies also revealed that carbon sequestration potential of degraded land increased with the implementation of SSD projects. The principal component analysis (PCA) showed that % OC, ECe, ALPA, available N and K content were the most contributing factor for soil quality index (SQI). The overall result of the studies showed that SSD technology holds great potential to improve soil quality, increase crop productivity, farmers' income and ensure land degradation neutrality and food security in waterlogged saline areas of western Indo Gangetic Plain of India. Hence, it can be concluded that large scale adoption of SSD may fulfill the promise “No poverty, Zero hunger, and Life on land” sustainable development goals of United Nation in degraded waterlogged saline areas.Not Availabl

Combination of Shape-Memory Polymers and Metal Alloys

Stimuli-responsive metal alloys and polymers considerably varied their properties like mechanical, optical, electrical properties, and shape upon exposure to external conditions like temperature, light, electric field, etc. This chapter gives comprehensive detail about shape-memory polymers (SMPs) and shapes metal alloys (SMAs) along with the application and their mechanism in different stimulus conditions. It presents an extensive review of the recent progress of combined SMPs and SMAs composites with design feasibility and fabrication by various methods for different applications.Scopu