Search results for "Power analysis"
showing 4 items of 4 documents
A novel secure aggregation scheme for wireless sensor networks using stateful public key cryptography
2015
International audience; Wireless sensor networks (WSNs) are nowadays considered as an important part of the Internet of Things (IoT). In these networks, data aggregation plays an essential role in energy preservation. However, WSNs are usually deployed in hostile and unattended environments (e.g. military applications) in which the confidentiality and integrity security services are widely desired. Recently, homomorphic encryptions have been applied to conceal sensitive information during aggregation such that algebraic operations are done directly on ciphertexts without decryption. The main benefit is that they offer the end-to-end data confidentiality and they do not require expensive com…
Effects of Interrater Reliability of Psychopathologic Assessment on Power and Sample Size Calculations in Clinical Trials
2002
Although rater training is increasingly used to improve the quality of the investigated outcome parameters, the reliability of assessments is not perfect. Thus, empirical reliability estimates should be used instead of theoretically assumed perfect reliability. Implications of the reliability of psychiatric assessments for sample size and power calculations in clinical trials are presented. The theoretical basis of sample size and power calculations using empirical reliability scores is delineated. Examples from contemporary research on schizophrenia and depression are used to illustrate several implications for study design and interpretation of results. The tremendous impact of the lack o…
Individual measurements and nested designs in aquaculture experiments: a simulation study
1998
Simple and nested models for analysis of variance (ANOVA) in aquaculture experiments were compared with the help of computer simulations. Simple models for analysing variables that are based on tank means, such as final weight and growth rate, were found to be sensitive to differences in the number of individual observations in each tank. In comparison to nested models that take into account individual measurements, the simple models were found to overestimate the F ratio and increase the risk of committing type I error, i.e., accepting a false alternative hypothesis. Further, nested models permit greater flexibility in experimental design, and allow more economical solutions within a given…
Efficiency, costs and market power analysis of the Spanish Port System
2021
El presente trabajo tiene diferentes objetivos. El primero es calcular la eficiencia técnica de las autoridades portuarias en la prestación de servicios sobre tráfico de mercancías y pasajeros en el periodo 2002- 2018. Para llevar a cabo este objetivo, se utiliza una función distancia orientada al output y se estima la eficiencia técnica a partir de una función frontera del tipo estocástico (SFA). Del mismo modo, se emplea la metodología no paramétrica (DEA) bajo dos supuestos alternativos, o bien bajo rendimientos constantes a escala (modelo de Charnes, Cooper y Rhodes, 1978), o bien bajo rendimientos variables a escala (modelo de Banker, Charnes y Cooper, 1984). Este análisis nos permite …