Analysis is made of the accuracy of magneticobservatory hourly means constructed from definitive minute data having missing values (gaps). Bootstrap sampling from different data-gap distributions is used to estimate average errors on hourly means as a function of the number of missing data. Absolute and relative error results are calculated for horizontal-intensity, declination, and vertical-co...

This paper investigates empirically the factors that influence real agricultural wage rates in Ghana, based on 1957 to 1991 data. The Johansen cointegration framework is used to examine long-run relationships among agricultural and urban wage rates, the domestic terms of trade between agriculture and nonagriculture, urban unemployment, capital stock in agriculture and the size of the rural popu...

wireless sensor networks attracting a great deal of research interest. accurate localization of sensor nodes is a strong requirement in a wide area of applications. in recent years, several techniques have been proposed for localization in wireless sensor networks. in this paper we present a localization scheme with using only one mobile anchor station and received signal strength indicator tec...

abstract major of hydrological systems are very complicated and it is not possible to understand them completely, therefore simplification is necessary to understand or control of a part of the system behavior such as water balance relationships. hydrological models are simple structure of complicated systems in water cycle in the nature. the first goal of a hydrological model is function predi...

In situ observation of the aerosol optical properties is important to the validations of satellite and modeling results; however, the operational measurements can be affected by some objective factors. An experiment study has been performed in order to analyze the error in retrievals of aerosol optical properties from sunphotometer measurements caused by a variety of in situ objective factors. ...

BACKGROUND Step counters have been used to observe activity and support physical activity, but there is limited evidence on their accuracy. OBJECTIVE The purpose was to investigate the step accuracy of the Fitbit Zip (Zip) in healthy adults during treadmill walking and in patients with cardiac disease while hospitalised at home. METHODS Twenty healthy adults aged 39±13.79 (mean ±SD) wore fo...