Correction to: Route reassessment by transporter ants improves speed and directional accuracy of cooperative transport in Formica japonica

The article Route reassessment by transporter ants improves speed and directional accuracy of cooperative transport in Formica japonica, written by Shumpei Hisamoto, Natsumi Hosaka, Yuka Matsunami, Hideo Iwasaki, was originally published Online First without Open Access.

Route reassessment by transporter ants improves speed and directional accuracy of cooperative transport in Formica japonica

Encircling cooperative transport in ants is categorized into coordinated and uncoordinated types. Coordinated cooperative transport is considered to be advantageous for ants because it transports food quickly without creating a deadlock. Contrarily, uncoordinated transport is slow and frequently becomes deadlocked. This study assessed the characteristics of uncoordinated cooperative transport, which has scarcely been studied before, through experiments performed on Formica japonica. Based on our experiment and analysis, we report that the transport speed remains unchanged with the number of transporters. We also found that pulling transporter ants often left the food item transiently as the transport speed decreased, and then went back to the item. Upon rejoining transport, the transport speed increased. This is presumably because the ants gain navigation information during the period that they leave the food. We propose that this ‘route reassessment’ behavior is important for transport coordination and navigation in F. japonica.

DIRECTIONAL ACCURACY OF SINGAPORE’S MACROECONOMIC FORECASTS

This study examines the directional accuracy of Singapore’s macroeconomic forecasts by professional forecasters, government agencies (i.e., central bank and Ministry of Trade and Industry, MTI), and international organizations. The results show that government agencies provide the most directionally accurate forecasts, suggesting that the macroeconomic and monetary policies are effective. Current-year forecasts are generally directionally accurate, with disparities among forecasters for next-year forecasts. Regarding GDP growth, the MTI and International Monetary Fund (IMF) provide directionally accurate forecasts up to four quarters ahead, whereas other forecasters provide them for at most three quarters ahead. For consumer price index inflation, except for the IMF, all others provide directionally accurate forecasts up to four quarters ahead.

Long-Term Electricity Load Forecasting Considering Volatility Using Multiplicative Error Model

Long-term electricity load forecasting plays a vital role for utilities and planners in terms of grid development and expansion planning. An overestimate of long-term electricity load will result in substantial wasted investment on the construction of excess power facilities, while an underestimate of the future load will result in insufficient generation and inadequate demand. As a first of its kind, this research proposes the use of a multiplicative error model (MEM) in forecasting electricity load for the long-term horizon. MEM originates from the structure of autoregressive conditional heteroscedasticity (ARCH) model where conditional variance is dynamically parameterized and it multiplicatively interacts with an innovation term of time-series. Historical load data, as accessed from a United States (U.S.) regional transmission operator, and recession data, accessed from the National Bureau of Economic Research, are used in this study. The superiority of considering volatility is proven by out-of-sample forecast results as well as directional accuracy during the great economic recession of 2008. Historical volatility is used to account for implied volatility. To incorporate future volatility, backtesting of MEM is performed. Two performance indicators used to assess the proposed model are: (i) loss functions in terms of mean absolute percentage error and mean squared error (for both in-sample model fit and out-of-sample forecasts) and (ii) directional accuracy.