Introduction to the Study of Animals

Because the objective of a study will largely determine the methods used, it is essential to define the objectives at the outset. Very broadly, studies may be defined as either extensive and intensive. Extensive studies are carried out over larger areas or longer time periods than intensive studies, and are frequently used to provide information on distribution and abundance for conservation or management programmes. Intensive studies involve the repeated observation of the population of an animal. The different types of population estimates—absolute, relative, and intensity—are described. The estimation of error and confidence intervals, including jackknife and bootstrap techniques, is described.

Youth Unemployment and Underdevelopment in Honduras

This paper analyzes the determinants and consequences of youth unemployment in Honduras. The study is based on the estimation of error correction models that express youth unemployment in terms of real sector variables. The results indicate that exports, remittances and self employment reduce youth unemployment, while the expansion of the service sector increases it; other results show that youth unemployment is susceptible to economic activity in the other Central American countries, specifically to economic growth in Guatemala, El Salvador and Nicaragua. Youth unemployment exerts negative impacts on Honduras’ productivity and on economic growth. The study also highlights the role of education on preventing youth unemployment and the importance of designing a Youth Agenda that would comprise several initiatives that are of special value to Honduran youth. It is hoped that these results would motivate policy makers and society in general to increase investments in the human capital areas so that youth avoid falling into the traps resulting from unemployment.

ESTIMATION OF ERROR IN MEASURING THE DEPTH OF SURFACE CRACKS BY THE ELECTROPOTENTIAL METHOD ON AN ALTERNATING CURRENT

The study carried out research on the error in measuring the depth of surface cracks by the electropotential method on an alternating current with a variation in the magnetic permeability and specific electrical conductivity of the metal. The measuring error appear from the difference between the electromagnetic properties of the metal of the sample used to obtain the calibration dependences and the properties of the metal of the tested object. The research conducted by the method of the finite element. The analysis of the dependences of the electropotential signal in the frequency range for the defect-free area and the area with a surface crack is carried out. The study of the error in measuring the depth h, that depends on the frequency of the transmitted current and the value of h. The comparison of the errors arising from various methods of choosing the calibration characteristics is performed, including the comparison of the equality of electropotential signals in the defect-free areas of the tested area and the test sample selected for calibration.

Analysis of the Effect of Machining Sequence on Machining Error Considering Workpiece Rigidity Change

The objective of this research is to investigate relations between individual physical phenomena and machining error from the measured machined error. Small lot production using numerical control machine tools is widely applied to high quality and high value-added products. In such production, agile and flexible machining is required. Thus, there have been many researches which investigate the effect of specific phenomena such as cutting force, thermal expansion, tool wears, chattering vibration and so on, which is to realize high precision machining. However, there have been some unsolved problems. The first problem is focused phenomena are mostly cutting force and/or machine tool deflection. Accordingly, other effects such as the results by workpiece rigidity change have not been investigated enough. The second problem is that the generation process of machining error is complicated and there is no proper method to compensate. Because of those complicate process, it is difficult to determine the dominant error factor of a new machining case in advance. Therefore, on-machine error measurement and estimation of error factors are essential technologies in order to achieve accuracy assurance. Recently, machining for rib-structured and thin-walled workpiece becomes important because of their higher structure efficiency and light weight characteristic. In this paper, the effect of workpiece rigidity to the machining error is investigated. Depend on the machining sequence, workpiece rigidities change differently during the machining process. Two different machining cases with different machining sequences are conducted and difference between the cases are investigated.

WEB APPLICATION FOR MEASURING OF THE COMPONENTS CONTENT WITH PHASE TRANSITION IN HETEROGENEOUS MATERIALS

The possibility of using raster images to improve the accuracy of processing differential thermal analysis (DTA) data is considered. Estimation of error in measuring of components content with a phase transition in heterogeneous materials by the DTA data presented in the form of raster images was made. Using languages HTML, CSS, JavaScript as well as Canvas technology, a web-application for processing DTA data presented as raster images was created. The application allows measuring the relative content of components with a phase transition in heterogeneous materials with an error of 3% by scan data of peaks in DTA curves. The application created in this work can use any Internet browser as a software environment.

Underlying Fundamentals of Kalman Filtering for River Network Modeling

The grand challenge of producing hydrometeorological estimates every time and everywhere has motivated the fusion of sparse observations with dense numerical models, with a particular interest on discharge in river modeling. Ensemble methods are largely preferred as they enable the estimation of error properties, but at the expense of computational load and generally with underestimations. These imperfect stochastic estimates motivate the use of correction methods, that is, error localization and inflation, although the physical justifications for their optimality are limited. The purpose of this study is to use one of the simplest forms of data assimilation when applied to river modeling and reveal the underlying mechanisms impacting its performance. Our framework based on assimilating daily averaged in situ discharge measurements to correct daily averaged runoff was tested over a 4-yr case study of two rivers in Texas. Results show that under optimal conditions of inflation and localization, discharge simulations are consistently improved such that the mean values of Nash–Sutcliffe efficiency are enhanced from −11.32 to 0.55 at observed gauges and from −12.24 to −1.10 at validation gauges. Yet, parameters controlling the inflation and the localization have a large impact on the performance. Further investigations of these sensitivities showed that optimal inflation occurs when compensating exactly for discrepancies in the magnitude of errors while optimal localization matches the distance traveled during one assimilation window. These results may be applicable to more advanced data assimilation methods as well as for larger applications motivated by upcoming river-observing satellite missions, such as NASA’s Surface Water and Ocean Topography mission.