A Term Structure Model for Commodity Prices: Does Storability Matter?

Econometric models of commodity prices have been estimated for more than 80 years, but both structural and time series models require ad hoc assumptions to capture all the features of commodity price series. Commodities can be broadly divided into two categories: storable and non-storable. The purpose of this study is to investigate the effects of storability on commodity futures pricing, especially whether meats can be reasonably approximated by storable commodity term structure models. From the empirical analysis of seven commodity futures prices, the two-factor Schwartz model is found to perform well for less storable commodities.Demand and Price Analysis,

Storability on Modeling Commodity Futures Prices

Econometric models of commodity prices have been estimated for more than 80 years, but both structural and time series models require ad hoc assumptions to capture all the features of commodity price series. Commodities can be broadly divided into two categories: storable and non-storable. The purpose of this study is to investigate the effects of storability on commodity futures pricing, especially whether meats can be reasonably approximated by storable commodity term structure models. From the empirical analysis of seven commodity futures prices, the two-factor Schwartz model is found to perform well for less storable commodities.Marketing,

Adapting Visual Question Answering Models for Enhancing Multimodal Community Q&A Platforms

Question categorization and expert retrieval methods have been crucial for information organization and accessibility in community question & answering (CQA) platforms. Research in this area, however, has dealt with only the text modality. With the increasing multimodal nature of web content, we focus on extending these methods for CQA questions accompanied by images. Specifically, we leverage the success of representation learning for text and images in the visual question answering (VQA) domain, and adapt the underlying concept and architecture for automated category classification and expert retrieval on image-based questions posted on Yahoo! Chiebukuro, the Japanese counterpart of Yahoo! Answers. To the best of our knowledge, this is the first work to tackle the multimodality challenge in CQA, and to adapt VQA models for tasks on a more ecologically valid source of visual questions. Our analysis of the differences between visual QA and community QA data drives our proposal of novel augmentations of an attention method tailored for CQA, and use of auxiliary tasks for learning better grounding features. Our final model markedly outperforms the text-only and VQA model baselines for both tasks of classification and expert retrieval on real-world multimodal CQA data.Comment: Submitted for review at CIKM 201

Subclasses of Normal Helly Circular-Arc Graphs

A Helly circular-arc model M = (C,A) is a circle C together with a Helly family \A of arcs of C. If no arc is contained in any other, then M is a proper Helly circular-arc model, if every arc has the same length, then M is a unit Helly circular-arc model, and if there are no two arcs covering the circle, then M is a normal Helly circular-arc model. A Helly (resp. proper Helly, unit Helly, normal Helly) circular-arc graph is the intersection graph of the arcs of a Helly (resp. proper Helly, unit Helly, normal Helly) circular-arc model. In this article we study these subclasses of Helly circular-arc graphs. We show natural generalizations of several properties of (proper) interval graphs that hold for some of these Helly circular-arc subclasses. Next, we describe characterizations for the subclasses of Helly circular-arc graphs, including forbidden induced subgraphs characterizations. These characterizations lead to efficient algorithms for recognizing graphs within these classes. Finally, we show how do these classes of graphs relate with straight and round digraphs.Comment: 39 pages, 13 figures. A previous version of the paper (entitled Proper Helly Circular-Arc Graphs) appeared at WG'0

Plasmonic edge states: an electrostatic eigenmode description

We consider periodic arrangements of metal nanostructures and study the effect of periodicity on the localised surface plasmon resonance of the structures within an electrostatic eigenmode approximation. We show that within this limit, the collective surface plasmon resonances of the periodic structures can be expressed in terms of superpositions of the eigenmodes of uncoupled nanostructures that exhibit a standing--wave character delocalised across the entire periodic structure. The formalism derived successfully enables the design and accounts for the observation of plasmonic edge-states in periodic structures

Predicting and explaining behavioral intention and hand sanitizer use among US Army soldiers

Citation: Naiqing Lin, Kevin R. Roberts, (2017) Predicting and explaining behavioral intention and hand sanitizer use among US Army soldiers, In American Journal of Infection Control, 45(4),396-400. https://doi.org/10.1016/j.ajic.2016.11.008.According to the Centers for Disease Control and Prevention and the World Health Organization, simple hand washing is one of the most effective methods to prevent the spread of infectious diseases.1,2,3 The literature shows a strong and consistent association between personal hand hygiene and reduced gastrointestinal disease, respiratory illness, and absenteeism in the work force.1,4,5 Hands are the primary mode of transmission for many infectious diseases, particularly among military personnel.6 Hand hygiene is a proven measure of controlling infection in military settings