Semi-Supervised Radio Signal Identification

Radio emitter recognition in dense multi-user environments is an important tool for optimizing spectrum utilization, identifying and minimizing interference, and enforcing spectrum policy. Radio data is readily available and easy to obtain from an antenna, but labeled and curated data is often scarce making supervised learning strategies difficult and time consuming in practice. We demonstrate that semi-supervised learning techniques can be used to scale learning beyond supervised datasets, allowing for discerning and recalling new radio signals by using sparse signal representations based on both unsupervised and supervised methods for nonlinear feature learning and clustering methods

Cost-sensitive Learning for Utility Optimization in Online Advertising Auctions

One of the most challenging problems in computational advertising is the prediction of click-through and conversion rates for bidding in online advertising auctions. An unaddressed problem in previous approaches is the existence of highly non-uniform misprediction costs. While for model evaluation these costs have been taken into account through recently proposed business-aware offline metrics -- such as the Utility metric which measures the impact on advertiser profit -- this is not the case when training the models themselves. In this paper, to bridge the gap, we formally analyze the relationship between optimizing the Utility metric and the log loss, which is considered as one of the state-of-the-art approaches in conversion modeling. Our analysis motivates the idea of weighting the log loss with the business value of the predicted outcome. We present and analyze a new cost weighting scheme and show that significant gains in offline and online performance can be achieved.Comment: First version of the paper was presented at NIPS 2015 Workshop on E-Commerce: https://sites.google.com/site/nips15ecommerce/papers Third version of the paper will be presented at AdKDD 2017 Workshop: adkdd17.wixsite.com/adkddtargetad201

Technical Efficiency Measurement within the Ivorian Manufacturing Sector: a Data Envelopment Analysis Approach

The African industrial structure is characterised by a strong firm-size heterogeneity with a co-existence of small if not micro-enterprises of the informal sector and large formal organisations operating with a modern technology. In this paper, we investigate the technical efficiency of Ivorian manufacturing firms in four sectors of economic activity: textile and garment, metal products, wood and furniture, food processing. The DEA production frontier is the non-parametric methodology to which we refer to. Efficiency scores are calculated by following the four-stage procedure as presented by Fried, Schmidt and Yaisawarng (1999). In other words, the initial DEA scores are adjusted to take into account the impact of the external operating environment on the volume of the input use. Technical efficiency are then decomposed into three elements: the pure managerial effect, the impact of the production scale, but also a technological effect capturing the potential gain that could result from the adoption of the modern technology by small informal firms.formal-informal sectors, manufacturing sector, non parametric frontier, cote d'ivoire, Technical efficiency

Trends in crypto-currencies and blockchain technologies: A monetary theory and regulation perspective

The internet era has generated a requirement for low cost, anonymous and rapidly verifiable transactions to be used for online barter, and fast settling money have emerged as a consequence. For the most part, e-money has fulfilled this role, but the last few years have seen two new types of money emerge. Centralised virtual currencies, usually for the purpose of transacting in social and gaming economies, and crypto-currencies, which aim to eliminate the need for financial intermediaries by offering direct peer-to-peer online payments. We describe the historical context which led to the development of these currencies and some modern and recent trends in their uptake, in terms of both usage in the real economy and as investment products. As these currencies are purely digital constructs, with no government or local authority backing, we then discuss them in the context of monetary theory, in order to determine how they may be have value under each. Finally, we provide an overview of the state of regulatory readiness in terms of dealing with transactions in these currencies in various regions of the world

Shareholding Cascades: The Separation of Ownership and Control in Belgium

This paper analyses the control of Belgian listed companies. The analysis reveals that control of listed companies in Belgium is highly concentrated. Business groups, holding companies, and voting pacts, play an important role in bringing about this concentration. The main characteristics of the Belgian corporate ownership and equity market can be summarised as follows : (i) few - merely 140 - Belgian companies are listed on the Brussels stock exchange, (ii) there is a high degree of ownership concentration with an average largest direct shareholding of 45%, (iii)holding companies and families, and to a lesser extent industrial companies, are the main investor categories whose share stakes are concentrated into powerful control blocks through business group structures and voting pacts, (iv) control is levered by pyramidal and complex ownership structures and (v) there is a market for share stakes.Ownership;control;corporate governance

Fluid-structure interactions of anisotropic thin composite materials for application to sail aerodynamics of a yacht in waves

In recent years technological innovations has allowed large improvements to be made in sail design and construction. Sails and in particular kite-sails have application for sport, ships’ auxiliary propulsion and even power generation. Sails are divided into upwind and downwind sails (Fig.1), where upwind sails operate as lifting surfaces with small angles of attack whereas traditional downwind sails acted as drag device. New designs of downwind sails have reduced the area of separated flow and increased the lifting behaviour of the sails. In order to capture the lifting behaviour and regions of separation present in both types of sail careful application of computational fluid dynamic analysis tools are required. Solutions of the Reynolds averaged Navier- Stokes equations (RANSE) are often used as a part of the design process of high performance sailing yachts.The present paper discusses some initial investigations and future guidelines in order to get a more detailed description of the physics involved in sail FSI. Three main fields are therefore covered: the use of CFD in order to accurately capture flow features and a comparison with experimental results; structural modelling; and approach to couplin

TREEWIDTH and PATHWIDTH parameterized by vertex cover

After the number of vertices, Vertex Cover is the largest of the classical graph parameters and has more and more frequently been used as a separate parameter in parameterized problems, including problems that are not directly related to the Vertex Cover. Here we consider the TREEWIDTH and PATHWIDTH problems parameterized by k, the size of a minimum vertex cover of the input graph. We show that the PATHWIDTH and TREEWIDTH can be computed in O*(3^k) time. This complements recent polynomial kernel results for TREEWIDTH and PATHWIDTH parameterized by the Vertex Cover