Average Sampling Rate Research Articles

Development of Anemometer Based on Inertial Sensor.

The current article elucidates a study centered on the development of an anemometer leveraging an inertial sensor for wind speed measurement in the northeast region of Brazil, focusing on renewable energy generation. The study encompassed a series of experiments aimed at calibrating the anemometer, analyzing the noise generated by the inertial sensor, and scrutinizing the data acquired during wind speed measurement. The calibration process unfolded in three stages: initial noise analysis, subsequent inertial data analysis, and the derivation of calibration curves. The first two stages involved experiments conducted at an average sampling rate of 10 Hz. Simultaneously, the third stage incorporated data collected over a 1 h duration while maintaining the same sampling rate. The outcomes underscore the suitability of the anemometer based on an inertial sensor for wind energy systems and diverse applications. While the wind readings from the prototype exhibit considerable fluctuations, a three-length moving average filter is applied to the prototype's output to mitigate these fluctuations. The calibration surface was established using observational data, and the resultant surface is detailed. Data analysis assumes paramount significance in wind speed measurement, and the K-NN algorithm demonstrated superior efficacy in estimating the correspondence between measured and control data.

Blind power spectrum reconstruction for multi-sinusoid signals with generative multicoset sampling

As the target frequency increases, the Nyquist rate is hard to reach due to hardware limitations. Alternatives to high-rate sampling have attracted considerable research interest. Compressed covariance sensing based on multicoset sampling (MCS) is a prevalent sub-Nyquist sampling strategy for blind power spectrum reconstruction. However, it requires the sampling pattern of MCS to be a minimal sparse ruler. In this paper, a generative multicoset sampling (GMCS) is proposed to minimize the number of cosets. In the sampling stage, a minimal MCS, delay coprime scheme is proposed to ensure the recoverability of the power spectrum. In the recovery stage, a new function, i.e., multifold correlation is constructed for blind power spectrum reconstruction. We prove that the power spectrum of a multi-sinusoid signal (MSS) can be estimated by its multifold correlation and the sample density of multifold correlation can be increased by correlation operations. Owing to multifold correlation, GMCS can generate virtual cosets satisfying the sparse ruler criterion through only two physical cosets and then efficiently recover the power spectrum by least-squares estimation. Moreover, we demonstrate the feasibility of GMCS for linear frequency modulation (LFM) signals. Finally, the effectiveness of GMCS are verified by numerical simulations and blade tip timing experiments (a non-contact vibration measurement). By reducing the average sampling rate and hardware complexity, GMCS opens new avenues for blind sampling and power spectrum reconstruction.

Scheme design and flow performance analysis of double-bits combination wire-line coring technology for seafloor drill

In order to meet the requirement of high-quality samples for evaluating marine mineral resources reserves, a double-bits combination wire line coring scheme for seafloor drill is proposed. The Bernoulli math model reflecting the drilling fluid pressure variation inside the drilling tool is established. The influence of the drilling tool’s water circuit parameters on the drilling fluid pressure variation is clarified. The drilling fluid’s flow performance during the drilling process is analyzed. The drilling performance of this scheme is tested through engineering application. The application results indicate that: When the inner tube bit’s water channel cross-section A1 reaches 30mm2, A2 reaches 20mm2 and the A3 reaches 20mm2, the drilling fluid pressure ΔP in the drilling tool tends to stabilize. The influence of PVC tube outside diameter d8 on drilling fluid pressure ΔP is small within the allowable design range of 62–65mm. The simulation results show a high-speed area in the first section of the water channel in the inner tube bit. Selecting pump displacement in 50–90 L/min has more engineering application value. The engineering application in complex seabed strata shows that the average core sampling rate is more than 85% within the pump displacement of 50-90 L/min and rotation speed of 350–450 r/min.

Understanding the bias of mobile location data across spatial scales and over time: A comprehensive analysis of SafeGraph data in the United States.

Mobile location data has emerged as a valuable data source for studying human mobility patterns in various contexts, including virus spreading, urban planning, and hazard evacuation. However, these data are often anonymized overviews derived from a panel of traced mobile devices, and the representativeness of these panels is not well documented. Without a clear understanding of the data representativeness, the interpretations of research based on mobile location data may be questionable. This article presents a comprehensive examination of the potential biases associated with mobile location data using SafeGraph Patterns data in the United States as a case study. The research rigorously scrutinizes and documents the bias from multiple dimensions, including spatial, temporal, urbanization, demographic, and socioeconomic, over a five-year period from 2018 to 2022 across diverse geographic levels, including state, county, census tract, and census block group. Our analysis of the SafeGraph Patterns dataset revealed an average sampling rate of 7.5% with notable temporal dynamics, geographic disparities, and urban-rural differences. The number of sampled devices was strongly correlated with the census population at the county level over the five years for both urban (r > 0.97) and rural counties (r > 0.91), but less so at the census tract and block group levels. We observed minor sampling biases among groups such as gender, age, and moderate-income, with biases typically ranging from -0.05 to +0.05. However, minority groups such as Hispanic populations, low-income households, and individuals with low levels of education generally exhibited higher levels of underrepresentation bias that varied over space, time, urbanization, and across geographic levels. These findings provide important insights for future studies that utilize SafeGraph data or other mobile location datasets, highlighting the need to thoroughly evaluate the spatiotemporal dynamics of the bias across spatial scales when employing such data sources.

An unconstrained relaxation digital‐to‐analog converter using optimal bit sequence

AbstractBased on the relaxation digital‐to‐analog converter (ReDAC) architecture and the capacitor charge/discharge function under discrete time conditions, this paper proposes a new mathematical model for the output voltage of the ReDAC to implement the unconstrained relaxation DAC (Uc‐ReDAC). The system clock calibration is not required. An adaptive probabilistic binary particle swarm optimization (AP‐BPSO) algorithm is proposed for solving the binary coding configuration problem under the Uc‐ReDAC model. Simulation results show that the 8‐bit (10‐bit) Uc‐ReDAC has an average sampling rate of 7.9 MS/s (6.76 MS/s).

High-Fidelity Compressive Heart Rate Tracking

Recently, photoplethysmography sensors in smart watches have been frequently used to monitor heart rate. Because a photoplethysmography sensor flashes light on the skin and measures the reflected light, the rate of flashing and sampling is directly related to its energy consumption. It is necessary to reduce the rate to extend the battery life of a smart watch. In this study, to satisfy sub-Nyquist sampling, real-time, and high accuracy requirements, we propose a novel heart rate tracking method that consists of online compressive covariance sensing, signal subspace tracking, and spectral peak tracking. The proposed method (average sampling rate: 1.4 Hz) showed better frequency tracking performance than the conventional spectral peak tracking algorithm (sampling rate: 10 Hz) in time-varying heart rate simulations, and a statistically significant difference between them was not observed in the real photoplethysmogram data. The trimmed average absolute error was 1.04 beats/min. As a result, the proposed real-time heart rate tracking method with sub-Nyquist sampling showed high accuracy.

An innovative passive sampler to reveal the high contribution of biomass burning to black carbon over Indo-China Peninsula: Radiocarbon constraints

Black carbon (BC) is an important component of the brown clouds, contributing to climate and health effects of air pollution. In this work, we developed a new method for measuring BC concentrations and its radiocarbon isotope (14C) using quartz wool disk passive air samplers (Pas-QW). A field calibration study was conducted at two sampling sites (Guangzhou and Yantai), using an improved thermal/optical method to measure BC. Uptake profiles of Pas-QW were linear over the 77 days that the samplers were deployed, and the average sampling rate of BC measured was 1.1 ± 0.2 m3/day. The method was found to be reproducible with coefficients of variation as low as 17% for BC measured in ambient passive samples. Furthermore, passive sampling was carried out at six sites in the Indo-China Peninsula (ICP) from January to April and June to September of 2016. The high BC concentrations and the high fraction of modern carbon (fM) values emphasizes that ICP is still dominated by biomass burning emissions (residential cooking and agricultural burning), both in dry and wet seasons. This study provides a proof concept and methodology for the application of Pas-QW to cost-effectively expand measurements of BC at the global scale.

RJAfinder: An automated tool for quantification of responding to joint attention behaviors in autism spectrum disorder using eye tracking data.

Deficits in responding to joint attention (RJA) are early symptoms of autism spectrum disorder (ASD). Currently, no automated tools exist for identifying and quantifying RJA behaviors. A few eye tracking studies have investigated RJA in ASD children but have produced conflicting results. In addition, little is known about the trajectory of RJA development through developmental age. Here, a new video was designed including 12 clips of an actor pointing to or looking at an object. Eye tracking technology was used to monitor RJA in three groups: 143 ASD children assessed with the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) (4-7 years old), 113 age- and gender-matched typically developing children (TDC), and 43 typically developing adults (TDA) (19-32 years old). RJAfinder was developed in R and MATLAB to quantify RJA events from the eye tracking data. RJA events were compared among the three groups. Spearman correlation coefficients between total number of RJA events in ASD and the Social Responsiveness Scale (SRS) scores were calculated. A logistic regression model was built using the average valid sampling rate and the total number of RJA events as two predictive variables to classify ASD and TDC groups. ASD children displayed statistically significantly less RJA events than the TDC and TDA groups with medium-to-large-sized effects. ASD and TDC children both displayed more RJA events in response to pointing stimuli than to looking stimuli. Our logistic regression model predicted ASD tendency with 0.76 accuracy in the testing set. RJA ability improved more slowly between the ages of 4-7 years old in the ASD group than in the TDC group. In ASD children, RJA ability showed negative correlation with SRS total T-score as well as the scores of five subdomains. Our study provides an automated tool for quantifying RJA and insights for the study of RJA in ASD children, which may help improve ASD screening, subtyping, and behavior interventions.

Broadband Signal Digitization Based on Low-Speed Non-Uniform Photonic Sampling

A new non-uniform photonic sampling (NPS) strategy and its special signal reconstruction algorithm are proposed to achieve digital acquisition of broadband periodic signals at a low sampling rate. Compared with the existing schemes, the NPS strategy can largely reduce the sampling number to acquire identical signal information as that obtained by using its equivalent high-speed uniform photonic sampling, which is beneficial for reducing the sampling time and the data volume of the NPS-based analog-to-digital converter (ADC). In addition, the calculation time of the proposed algorithm is millions of times lower than that of the digital alias-free signal processing (DASP) algorithm used before, which benefits from the fast Fourier transform calculation of a one-dimensional data array instead of a two-dimensional data array calculation in the DASP algorithm. A simulation is performed to validate the feasibility of the proposed scheme. In the simulation, a single-channel NPS-based ADC with an average sampling rate of 1 GSa/s is demonstrated by using the proposed NPS strategy and signal reconstruction algorithm. The results indicate the reconstructed signal information for a single-tone microwave signal at 9.9 GHz and a linear frequency modulation signal in the frequency range of 1 GHz to 9 GHz are identical to those obtained by using its equivalent high-speed uniform photonic sampling-based ADC with a sampling rate of 20 GSa/s.

Validating ATLAS: A regional‐scale high‐throughput tracking system

Abstract Fine‐scale tracking of animal movement is important to understand the proximate mechanisms of animal behaviour. The reverse‐GPS system—ATLAS—uses inexpensive (~€25), lightweight (<1 g) and low‐power (~0.4 mJ/transmission) tags. Six systems are now operational worldwide and have successfully tracked over 50 species in various landscape types. The growing use of ATLAS to track animal movement motivates further refinement of best‐practice application and an assessment of its accuracy. Here, we test the accuracy and precision of the largest ATLAS system, located in the Dutch Wadden Sea, using concurrent GPS measurements as a reference. This large‐scale ATLAS system consists of 26 receivers and covers 1,326 km2 of intertidal region, with almost no physical obstacles for radio signals, providing a useful baseline for other systems. We compared ATLAS and GPS location estimates for a route (mobile test) and 16 fixed locations (stationary test) on the Griend mudflat. Precision was estimated using standard deviation during the stationary tests. We also give examples of tracked red knots Calidris canutus islandica to illustrate the use of the system in tracking small shorebirds (~120 g). ATLAS‐derived location estimates differed from GPS by a median of 4.2 m (stationary test) and 5.7 m (mobile test). Signals that were collected by more receiver stations were more accurate, although even three‐receiver localisations were comparable with GPS localisations (~10 m difference). Receivers that detected 90% of the 1 Hz transmissions from our test tag were within 5 km of their furthest detection but height of both receiver and tag seemed to influence detection distance. The test tag (1 Hz) had a fix rate of >90% at 15 of 16 stationary sites. Tags on birds (1/6 Hz) on the Griend mudflat had a mean fix rate of 51%, yielding an average sampling rate of 0.085 Hz. Fix rates were higher in more central parts of the receiver array. ATLAS provides accurate, regional‐scale tracking with which hundreds of relatively small‐bodied species can be tracked simultaneously for long periods of time. Future ATLAS users should consider the height of receivers, their spatial arrangement, density and the movement modes of their study species (e.g. ground‐dwelling or flying).

Fast Readout of Split-Ring Resonators Made Simple and Low-Cost for Application in HPLC

Split-ring resonators (SRR) are simple electrical circuits that show a significant shift in resonance frequency even with the smallest changes in split capacitance, and thus in permittivity, electric conductivity, and dielectric losses of the split capacitor’s dielectric. Usually, the resonance frequency is derived from the frequency response, but recording the frequency spectrum takes a certain amount of time. Here, we present a new capillary split-ring resonator CaSRR with fast readout for liquid chromatography (LC), which is capable of accurately detecting very fast changes in split capacity. The proposed method is based on the detection of the transmitted signal at a single frequency that is analyzed by demodulation. The demodulated signal changes its amplitude depending on the shift of the resonance frequency. Our simple low-cost electronics enables an average sampling rate of 42 Hz with 128 averages of the demodulated signal and has a frequency stability of 840 mHz. Thus, a minimum change in permittivity of Δεr,min = 11.26 × 10−3 can be detected. Finally, a chromatogram of one sugar (glucose) and one sugar alcohol (xylitol) is recorded using the SRR and is compared to a standard refractive index detector.

Broadband Vibration Signal Measurement Based on Multi-Coset Sampling in Phase-Sensitive OTDR System

The frequency response of phase-sensitive optical time-domain reflectometry ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi $ </tex-math></inline-formula> -OTDR) is strictly limited by the repetition rate of the injected sampling pulses in conventional sensing scheme. To fully reconstruct an arbitrary vibration signal, the pulse repetition rate is required to be lower bounded by twice the maximum frequency of the vibration signal according to the Nyquist sampling theorem and at the same time upper bounded by the sensing fiber length to avoid generations of mixed Rayleigh backscattered signals from more than one optical pulse within the sensing fiber, making high-frequency vibration sensing over long distance impossible. In this work, we propose a novel method based on the serial multi-coset sampling (MCS) strategy which can recover sparse broadband vibration signals with sub-Nyquist sampling rates, which is thus able to break through the tradeoff between the measurable vibration frequency bandwidth and the sensing range. Pulses with non-uniform intervals are adopted to realize MCS for the Rayleigh backscattered lights along the entire sensing fiber rather than the traditional uniform pulse train. A continuous to finite (CTF) block is used to determine the active spectrum ranges of the sparse signal. By using a serial MCS sequence with an average sampling rate of 4.8 kHz, both a 4 kHz single-frequency sinusoidal signal and a 0.2 kHz bandwidth chirped signal with a center frequency of 4.6 kHz were sampled and recovered successfully in the simulation. In experiments, a single frequency vibration signal of 15 kHz and a chirped vibration signal with frequency ranging from 15 to 16 kHz were successfully identified and reconstructed over a sensing distance of 4 km using an average sampling rate of 21.6kHz, respectively, which however is not possible in conventional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi $ </tex-math></inline-formula> -OTDR system. Furthermore, accurate identification of a broadband vibration signal with a maximum frequency of 6 kHz over a 10km-long sensing fiber shows that this method is also practically valid in long-distance sensing.

Spectrum Analysis for Multiband Signals With Nonuniform Sub-Nyquist Sampling in the Fractional Fourier Domain

This paper explores fractional spectrum analysis for periodically and nonuniformly sampled signals with finite disjoint bands in the fractional Fourier domain. Considering that spectrum aliasing occurs in sub-Nyquist sampling in the fractional Fourier domain, we study the conditions for reconstructing the fractional spectrum and devise relevant reconstruction methods. To obtain these goals, we investigate discrete-time fractional Fourier transform of the sampled signal that enables disjoint fractional frequency sub-intervals separated by aliasing boundaries. In order to implement perfect fractional spectrum reconstruction with reduced computations, we minimize the average sampling rate required by nonuniform sampling by means of properly choosing a sampling period. The theoretical lower bound on the optimized average sampling rate is much smaller than the lowest sampling rate required by uniform sampling under the same condition. Moreover, we derive the upper and lower bounds on the mean square error of fractional spectrum reconstruction with incorrect fractional spectrum modeling that assumes the signal as bandlimited to a large fractional frequency interval. Based on the derivations, we then obtain the optimal reconstruction parameters for spectrum reconstruction. Simulation results verify the effectiveness of our proposed methods.

Dual-band signal reconstruction based on periodic nonuniform sampling at optimal sampling rate

A continuous-time multi-band signal with arbitrary spectral support can be reconstructed from its periodic nonuniform samples with the average sampling rate being arbitrarily close to the Nyquist-Landau rate. However, according to the existing literature, the theoretical uniform sampling rate in each channel of a periodic nonuniform sampling system would be infinitely small. Also, the required number of channels would be impractically large, leading to numerous filters. Consequently, the corresponding systems would be too complicated for practical implementation. It is important to consider the tradeoff between sampling rate and complexity for such systems. In this paper, we address the exact recovery of the continuous-time dual-band signal from its periodic nonuniform samples at optimal sampling rate with a simple sampling and reconstruction system. Optimal sampling rate means that the sampling rate is reduced as close to the Nyquist-Landau rate as possible. Firstly, we develop constraints on the aliasing-free sampling frequency via first-order sampling. Then, sufficient conditions are given to reconstruct a uniform sequence from its periodic nonuniform samples at optimal sampling rate. The complexity of the proposed method is calculated, which is far less than that of the conventional scheme. Our method shows potential applications in orthogonal frequency-division multiplexing (OFDM) systems.

Determining Heavy Metals and other Elements Concentrations in the Soil at Baquba-Iraq

The present study aims to determine and calculate the concentration of some heavy elements (Pb, Hg, Cu, Ni, Fe, Cr, Co and Cd) in addition to the elements (Mg, Na, Ca, CL, K, C, S and SI), which are Possible sources of soil pollution in downtown (Baquba, Canaan, Muhammad Sakran, and Al-Mamal area), Diyala Governorate in Iraq. To achieve this goal, 5 samples of Diyala soil were collected. Soil samples included areas (industrial, residential, agricultural) with an average sample rate for each region with a depth (0-10 cm). After collecting the samples, they were sorted and compressed to prepare them for measurement by dispersive spectroscopy of X-ray energy (EDX) After obtaining the results, they are compared with the global determinants (WHO), and through these results we find that most of the heavy elements of the areas studied are recorded a significant rise for the element (pb), while the rise of (Cd) was recorded in the regions of Baquba and the Al-mameail region area also recorded an increase ( Cr) in the Canaan region, as well as the rise of some elements in the study area because they are residential and industrial areas and the use of fuels will be significant, while others found the lowest concentrations in agricultural areas with good vegetation knowing (Fe) was the lowest concentration in the study area.

The Concentration of the Toxic Elements (Cd, Hg, As) in Diyala Governorate Soil Utilizing GIS Techniques

The heavy elements (Cadmium, Mercury, and Arsenic) are considered to be highly toxicity for human and living creatures. This research focused on the concentrations of these elements in the soil of Diyala Governorate. The 25 samples of soil were collected from different areas included (industrial, residential, and agricultural) with an average sample rate for each region with a depth (10 cm). The samples were compressed to prepare them for measurement by dispersive spectroscopy of X-ray energy (EDX). The results are compared with the global determinants World Health Organization (WHO), where the results indicates the highest concentration of cadmium in the Injanah region and the lowest concentration in the Alma’amil region. The highest concentration of mercury in the regions of Mohammed Sakran and Diyala Bridge and the lowest concentration in the region of Mundhiriyah. The Arsenic elements concentrated become high in the Rashidiya region and less concentrated in the Hamrin hills region. It is known that these elements are more toxic than other elements when they are found in a higher rate than the permissible level in the soil.

Regional characteristics of atmospheric δ34S-SO42- over three parts of Asia monitored by quartz wool-based passive samplers.

A new method is presented for measuring atmospheric contents and δ34S-SO42- in airborne particulate matter using quartz wool disk passive air samplers (Pas-QW). The ability of Pas-QW samplers to provide time-integrated measurements of atmospheric SO42- was confirmed in a field calibration study. The average sampling rate of SO42- measured was 2.3±0.3m3/day, and this was not greatly affected by changes in meteorological parameters. The results of simultaneous sampling campaign showed that the average SO42- contents in Pakistan and the Indochina Peninsula (ICP) were relatively lower than that of China. The spatial distribution of SO42- concentrations was largely attributed to the development of the regional economies. The range of δ34S values observed in Pakistan (4.3±1.4‰) and the ICP (4.5±1.2‰) were relatively small, while a large range of δ34S values was observed in China (3.9±2.5‰). The regional distribution of sulfur isotope compositions was significantly affected by coal combustion. A source analysis based on a Bayesian mixing model showed that 80.4±13.1% and 19.6±13.1% of artificial sulfur dioxide (SO2) sources in China could be attributed to coal combustion and oil combustion, respectively. The two sources differed greatly between regions, and the contribution of oil combustion in cities was higher than previously reported data obtained from emission inventories. This study confirmed that the Pas-QW is a promising tool for simultaneously monitoring atmospheric δ34S-SO42- over large regions, and that the results of the isotope models can provide a reference for the compilation of SO2 emission inventories.

An Adaptive-Resolution Quasi-Level-Crossing Delta Modulator With VCO-Based Residue Quantizer

This brief introduces an adaptive-resolution (AR) quasi-level-crossing delta modulator ADC with a voltage-controlled oscillator (VCO)-based residue quantizer for Internet-of-Things (IoT) wireless sensor nodes. The residue voltage signal is digitized by a VCO-based residue quantizer, thus leading to a straightforward implementation of level-crossing (LC) and AR algorithms in digital domain. The inherent and mismatch-induced dithering provided by the VCO-based residue quantizer increases the proposed modulator’s dynamic range and average sampling rate for slowly-varying input signals, enabling accurate sampling and conversion. For fast-varying signals, the AR algorithm is adopted to reduce the average sampling rate by a factor of three compared to the straightforward LC algorithm at the edge of the modulator’s signal bandwidth. Fabricated in 28-nm CMOS, the proposed modulator achieves a peak SNDR of 53dB over a signal bandwidth of 1.78MHz.

Evaluation of (Ni, Cr, Cu) Concentration in the Soil of Diyala Utilizing GIS Techniques

The investigation of pollution’s elements were become the hot topics for the researchers. The current work aims to evaluate the concentration of some heavy elements Copper, Nickel, and Chrome (Cu, Ni, Cr) respectively. The study area of this research is Diyala province / Iraq. The base approach for this work is collecting 25 samples of soil to be studied. The samples were collected from (industrial, residential, agricultural) areas, with an average sample rate for each region with a depth (20 cm). After collecting the samples, they were sorted and compressed to prepare them for measurement by dispersive X-Ray Fluorescence. Analysis after obtaining the results, they are compared with the global determinants (WHO). Through these results, we find that a noticeable increase in the element (Ni) in Aleazim corking Khanaqin, Al-Rashidiya and Mohammed Sakran, while the highest concentration of (Cr) was recorded in jadidat alshat, Najana, Al -Rashidiya and Diyala Bridge. The (Cu) concentration was recorded high in the Aleazim Dam regoin, Aleazim, Muqdadiya, hayi Mezid, Al-Khalis, Rashidiya, Mohammed Sakran and Diyar Bridge. The residential and industrial areas were indicated an increasing in concentration of the investigated elements, while the areas with good vegetation have the lowest concentrations of these elements.

Optimized non-uniform sampling of blood pressure time series from the operating room.

We investigate an optimized non-uniform sampling strategy for blood pressure time series from the operating room (OR). Our aim is to obtain an approximate bound on the achievable reconstruction fidelity given an average sampling rate constraint. Our data set consists of 117 hours of recordings of continuous invasive blood pressure from 28 surgery patients. We evaluate the root mean squared error (RMSE) of the zero-order hold sampling reconstruction of the blood pressure time series. We quantitatively compare the errors achieved by uniform versus optimized non-uniform sample placements for several average sample rates, ranging from 2 to 24 measurements per hour. An optimized non-uniform measurement schedule can lead to approximately 50% reduction of reconstruction RMSE for systolic, mean, and diastolic blood pressure time series with respect to uniform sampling, while maintaining the same average sampling rate.