没有国界的国家馆

在去参加第53届威尼斯艺术双年展开幕式之前的几天,我受邀出席了在意大利北部城市Bergamo的当代美术馆GAMeC举行的国际年轻策展人论坛,今年论坛的主题是"国际策展人的终结?"围绕着像威尼斯双年展、卡塞尔文献展等全球达几十个之多的国际性展览的策展策略和模式进行反思和讨论。讨论之中也不免提到了威尼斯双年展这个一直以一个策展人为主导选择艺术家的大     

Automatic extraction of 1D barcodes from video scans for drone-assisted inventory management in warehousing applications

The widespread use of barcodes has significantly contributed to accurate, efficient and economic inventory management in warehouses and distribution centres. However, its efficiency has always been limited by the primary method of reading barcodes with a handheld laser scanner. Compared with this reading by line-of-sight at close proximity, vision-based barcode reading algorithms can further improve efficiency, particularly if accompanied by automated data collection platforms such as drones. This paper introduces algorithms that are able to automatically extract barcodes from video data, and verifies their feasibility and promise for inventory management in warehousing applications. Three key techniques corresponding to different recognition levels are proposed: For a known barcode region, a Harris corner detector and Hough transform-based algorithm is applied to quickly estimate the angle by which the frame area needs to rotate to orient the bars vertically for information extraction. Then, the idea of exploiting connectivity and geometry property of barcode areas is proposed to directly recognise multiple barcode regions in a single video frame to eliminate reading difficulties resulting from interactive influence of multiple juxtaposed barcodes, and to save computation time by only processing frame areas of interest for valid barcodes. In addition, a histogram difference-based fast extraction strategy is designed to further improve efficiency by reducing duplicate information processing. Finally, the performance of each technique is evaluated by analysing video data from a large logistics warehouse, demonstrating satisfactory performance in inventory management applications.     

Refinery mix in the U.S., Canada,and the E.E.C.

This paper examines the response of gasoline's share of a barrel of crude oil to changes in relative petroleum product prices. An inter-country comparison of the U.S., Canada, and the E.E.C. allows investigation of different parts of the production possibility frontier. In the U.S. and Canada, with relatively large amounts of cracking capacity, there is price responsiveness of the product mix to changes in relative product prices. In the U.S., both residual and distillates are substitutes in production for gasoline, but for Canada, only distillate is a substitute. Part of this difference is attributed to the U.S. oil quota. For the E.E.C. with relatively small amounts of cracking capacity there was no discernible effect of product prices on product mix.     

Monopsonistically/monopolistically competitive regional development: Public correction of market outcomes

A model of regional market development is constructed which captures the inefficiencies typical in most of the related literature, and a variety of corrective policy options are explored. For taxes and subsidies, there is no dominant policy with each limited by the zero-profit constraint on entry, informational problems, or adverse distributional considerations. Discriminatory pricing decreases efficiency, but uniform pricing achieves optimal allocations. Public production has certain informational advantages.     

CHILD MENTAL HEALTH AND EDUCATIONAL ATTAINMENT: MULTIPLE OBSERVERS AND THE MEASUREMENT ERROR PROBLEM

We examine the effect of survey measurement error on the empirical relationship between child mental health and personal and family characteristics, and between child mental health and educational progress. Our contribution is to use unique UK survey data that contain (potentially biased) assessments of each child's mental state from three observers (parent, teacher and child), together with expert (quasi‐)diagnoses, using an assumption of optimal diagnostic behaviour to adjust for reporting bias. We use three alternative restrictions to identify the effect of mental disorders on educational progress. Maternal education and mental health, family income and major adverse life events are all significant in explaining child mental health, and child mental health is found to have a large influence on educational progress. Our preferred estimate is that a one‐standard‐deviation reduction in ‘true’ latent child mental health leads to a 2‐ to 5‐month loss in educational progress. We also find a strong tendency for observers to understate the problems of older children and adolescents compared to expert diagnosis. © 2015 The Authors. Journal of Applied Econometrics published by John Wiley & Sons, Ltd.