Pesticides are widely used in agriculture where they do not only reach their targets but also distribute to other environmental compartments and negatively affect non-target organisms. To ...prospectively assess their environmental risk, several tools and models using pesticide persistence (DT50) and leaching potential (groundwater ubiquity score (GUS), EXPOSIT) have been developed. Here, we simultaneously quantified 18 pesticides in soil and drainage water during a conventionally grown potato culture at field scale with high temporal resolution and compared our findings with predictions of the above models. Overall dissipations of all freshly applied compounds in soil were in line with published DT50 field values and their occurrences in drainage water were generally consistent with GUS and EXPOSIT models, respectively. In contrast, soil concentrations of the legacy pesticide atrazine and one of its transformation products (atrazine-2-hydroxy) were constant during the entire sampling campaign. Moreover, during peak discharge atrazine concentrations in drainage water were diluted whereas those of freshly applied pesticides were maximal. This difference demonstrates that the applied risk assessment tools were capable of predicting environmental concentrations and dissipation of pesticides at the short and medium time scale of a few half-lives after application, but fell short of capturing long-term trace residues.
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•High frequency monitoring of pesticides in drainage water and soil•Pesticide dissipation in soil followed in general first order kinetics•Pesticide emission dynamics in drainage water varied substantially.•Legacy compounds behaved fundamentally differently to freshly applied ones.•Prospective and retrospective exposure assessments largely matched
Currently, little is known about the association between assessment intensity, burden, data quantity, and data quality in experience sampling method (ESM) studies. Researchers therefore have ...insufficient information to make informed decisions about the design of their ESM study. Our aim was to investigate the effects of different sampling frequencies and questionnaire lengths on burden, compliance, and careless responding. Students (n = 163) received either a 30- or 60-item questionnaire three, six, or nine times per day for 14 days. Preregistered multilevel regression analyses and analyses of variance were used to analyze the effect of design condition on momentary outcomes, changes in those outcomes over time, and retrospective outcomes. Our findings offer support for increased burden and compromised data quantity and quality with longer questionnaires, but not with increased sampling frequency. We therefore advise against the use of long ESM questionnaires, while high-sampling frequencies do not seem to be associated with negative consequences.
•Good and responsible management of bathing water quality requires a site-specific approach.•The frequency of bathing water sampling can influence the relevance of bathing water quality ...assessment.•Spatio-temporal variability in the density of fecal indicator bacteria influences the assessment of bathing water quality.•The monitoring of bathing water quality provided for in the current EU Bathing Water Directive should be redefined.
The time and location of sampling as well as the number of samples per season can influence a reliable assessment of bathing water quality. In this study, we investigated the spatio-temporal variation of fecal indicator bacteria (FIB) density and the effects of FIB variability and sampling frequency on the assessment of a single sample and the annual and final assessment of coastal bathing water quality. Increasing the number of samples from 10 to 20 per bathing season had a significant impact on bathing water quality assessment at sites where water quality fluctuations had previously been observed, resulting in a change in water quality to a lower category in 36 % of annual and 54 % of final assessments, suggesting that the minimum number of samples per season should be increased at such sites. Increasing the number of samples at sites assessed as excellent over a longer period had no impact on water quality assessment.
Spatial and temporal variations in FIB density were significant at a considerable number of sites both in the single sample assessment and in the annual and final assessment. Bathing water quality was spatially unrepresentative at a quarter of the sites analyzed and temporally unrepresentative at a fifth, as there was at least one additional point with a lower bathing water quality than the official sampling point or the bathing water quality was lower in the afternoon than in the morning.
When revising the current recreational water quality regulations, the impact of sampling frequency of and of spatio-temporal variation of FIB density on the relevance of bathing water quality assessment at sites subjected to pollution needs to be seriously considered.
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•A real-time plug load identification approach was proposed using low-frequency data.•The robustness of the approach was evaluated under different experimental settings.•The best online model ...reported accuracies up to 93% with response time of 5 min.•Energy dashboards and control systems were highlighted as future application areas.•The plug load dataset collected in this study was made publicly available online.
Plug loads account for up to one-third of the overall energy use in commercial buildings. There is thus a growing research interest in utilising load monitoring systems to track plug load usage by installing smart plugs to capture high-resolution consumption data. The availability of such data has also enabled the development of automatic plug load identification models that enhance the capabilities of existing load monitoring systems. Through our literature review, we highlighted several limitations that impede real-world implementation, such as the limited number of publicly available datasets for commercial buildings, models trained on data with high sampling frequencies while using an extended time window, and data leakage issues during model training. In this study, we proposed a near-real-time plug load identification approach that uses low-frequency power data (1/60 Hz) to identify plug loads in office spaces. The dataset used in this study is processed by first identifying the active periods of the plug loads before applying a novel dynamic time window strategy during feature extraction. These extracted features are subsequently passed through several classification algorithms and evaluated using different accuracy metrics. The proposed approach is also assessed through multiple experiments, including (1) identifying the best online and offline models, (2) comparing between different time window strategies, and (3) evaluating model performances under different sampling frequencies. As a result, the best online model achieved accuracies up to 93% using the Bagging algorithm with a minimum dynamic time window of 5 minutes. Finally, we highlighted two application areas of automatic plug load identification in energy dashboards and personalised control systems as part of future works.
The sampling frequency offset (SFO) will induce phase rotation, inter-symbol interference and inter-carrier interference, which may seriously deteriorate the receiver’s performance in asynchronous ...optical discrete multi-tone (DMT) systems. In this work, a high-accuracy training symbols-based SFO estimation (SFOE) method is studied in both the additive white Gaussian noise channel and short-reach directly-modulated laser-based DMT transmission system. Two general SFO compensation (SFOC) methods, i.e., digital interpolation (DI) and phase compensation (PC), are comparatively investigated through both simulations and experiments. The results indicate that the accuracy of the SFOE method can be within ±0.2 ppm under the SFO range of ±500 ppm and different received optical powers. With the high-accuracy SFOE method, the 4th order DI has the best compensation performance compared to PC, 2nd and 3rd order DI methods. Moreover, the negligible EVM performance penalty compared with the case of SFO-free can also be achieved in an optical DMT transmission system. Besides, the PC-based SFOC method has similar EVM performance to the 4th order DI in the case of small SFO within ±300 ppm.
•A high-accuracy training symbols-based SFO estimation method is proposed for short-reach DMT transmission.•The accuracy of the proposed SFOE is within ±0.2 ppm under the SFO range of ±500 ppm and different received optical powers.•Two commonly used SFO compensation methods of phase compensation and digital interpolation are experimentally investigated.
Considering the very large number of studies that have applied ambulatory assessment (AA) in the last decade across diverse fields of research, knowledge about the effects that these design choices ...have on participants’ perceived burden, data quantity (i.e., compliance with the AA protocol), and data quality (e.g., within-person relationships between time-varying variables) is surprisingly restricted. The aim of the current research was to experimentally manipulate aspects of an AA study’s assessment intensity—sampling frequency (Study 1) and questionnaire length (Study 2)—and to investigate their impact on perceived burden, compliance, within-person variability, and within-person relationships between time-varying variables. In Study 1, students (
n
= 313) received either 3 or 9 questionnaires per day for the first 7 days of the study. In Study 2, students (
n
= 282) received either a 33- or 82-item questionnaire three times a day for 14 days. Within-person variability and within-person relationships were investigated with respect to momentary pleasant-unpleasant mood and state extraversion. The results of Study 1 showed that a higher sampling frequency increased perceived burden but did not affect the other aspects we investigated. In Study 2, longer questionnaire length did not affect perceived burden or compliance but yielded a smaller degree of within-person variability in momentary mood (but not in state extraversion) and a smaller within-person relationship between state extraversion and mood. Differences between Studies 1 and 2 with respect to the type of manipulation of assessment intensity are discussed.
Automatic modulation classification facilitates many important signal processing applications. Recently, deep learning models have been adopted in modulation recognition, which outperform traditional ...machine learning techniques based on hand-crafted features. However, automatic modulation classification is still challenging due to the following reasons. Existing deep learning methods are only applicable to the data of the same distribution. In practical scenarios, data distribution is varying with sampling frequency, thus domains with different sampling rates are formed. Besides, it is difficult to construct large-scale well-annotated datasets for all domains of interest. We define the domain with sufficient data as the source domain, while the domain with insufficient data as the target domain. Obviously, the classification model performs weakly in the target domain. To address these challenges, we propose an adversarial transfer learning architecture (ATLA), incorporating adversarial training and knowledge transfer in a unified way. Adversarial training performs an asymmetric mapping between domains and reduces the domain shift. Knowledge transfer is used to mine prior knowledge from the source domain. Experimental results demonstrate that the proposed ATLA substantially boosts the performance of the target model, which outperforms the existing parameter-transfer approach. With half of the training data reduced, the target model achieves competitive recognition accuracy to supervised learning. With one-tenth of training data, the promoted accuracy is up to 17.3% points.
The surface water quality monitoring network (WQMN) is crucial for effective water environment management. How to design an optimal monitoring network is an important scientific and engineering ...problem that presents a special challenge in the smart city era. This comprehensive review provides a timely and systematic overview and analysis on quantitative design approaches. Bibliometric analysis shows the chronological pattern, journal distribution, authorship, citation and country pattern. Administration types of water bodies and design methods are classified. The flexibility characteristics of four types of direct design methods and optimization objectives are systematically summarized, and conclusions are drawn from experiences with WQMN parameters, station locations, and sampling frequency and water quality indicators. This paper concludes by identifying four main future directions that should be pursued by the research community. This review sheds light on how to better design and construct WQMNs.
•Design surface water WQMN is growing and more opportunities in developing countries.•Categories, flexibility, optimization objectives of WQMN design methods identified.•Design experiences on station location, sampling frequency, water quality indicator.•Implications to WQ modelling and smart city, adapt to complex network architectures.•Novel design method, coupling new requirement and monitoring tech., better practice.
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