The focus of this paper is to consider the compressed sensing problem. It is stated that the compressed sensing theory, under certain conditions, helps relax the Nyquist sampling theory and takes smaller samples. One of the important tasks in this theory is to carefully design measurement matrix (sampling operator). Most existing methods in the literature attempt to optimize a randomly initiali...

Constructing scientifically sound samples of hard-to-reach populations, also known as hidden populations, is a challenge for many research projects. Traditional sample survey methods, such as random sampling from telephone or mailing lists, can yield low numbers of eligible respondents while non-probability sampling introduces unknown biases. The authors describe a venue-based application of ti...

1.0 Introduction Systematic sampling (either with equal or unequal selection probabilities) is a common sampling scheme in complex sample designs. It is used because of its simplicity of implementation and its potential increase in efficiency, given a good frame ordering, which acts as an additional stratification. One problem with systematic sampling is that such samples can be viewed as a clu...

New sampling designs for the Autumn Portuguese bottom trawl survey (ptBTS) were investigated to explore alternative spatial configurations and possible increments on sample size. The currently used stratified random design and five proposals of systematic based designs were assessed by a simulation study, adopting a geostatistical approach based on likelihood methods of inference. The construct...

urvey research is an important form of scientific inquiry 1 that merits rigorous design and analysis. 2 The aim of a survey is to gather reliable and unbiased data from a representative sample of respondents. 3 Increasingly, investigators administer questionnaires to clinicians about their knowledge, attitudes and practice 2,4,5 to generate or refine research questions and to evaluate the impac...

Natural populations of plants and animals spatially cluster because (1) suitable habitat is patchy, and (2) within suitable habitat, individuals aggregate further into clusters of higher density. We compare the precision of random and systematic field sampling survey designs under these two processes of species clustering. Second, we evaluate the performance of 13 estimators for the variance of...

In sampling theory, a wide variety of techniques is used to obtain efficient estimators for the population mean. The commonly used method to obtain the estimator for population mean is simple random sampling without replacement (SRSWOR) when there is no auxiliary variable available. There are methods that use the auxiliary information of the study characteristics. If there exists an auxiliary v...

We augment the mechanism used in Nash implementation with a political process that collects the opinions of a subset of individuals with a fixed probability distribution. The outcome is a function of only the collected opinions. We show that the necessary – and sometimes sufficient – condition for implementation by a specific political process can be either weaker or stronger than Maskin monoto...

An expression for the spectral density of the impulse process s(t) = ~ :~ a~(t t,) is derived under the assumption that {an} is a s tat ionary process, and that {t~} is a stat ionary point process independent of {a~}. The spectral density appears as an infinite series in terms of the correlation of {a~} and the interval statistics of Its}. The same result was obtained b y Leneman by a different...