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Recent advances in Internet of Things (IoT) technologies have enabled the use of wearables for remote patient monitoring. Wearable sensors capture the patient’s vital signs, and provide alerts or diagnosis based on the collected data. Unfortunately, wearables typically have limited energy and computational capacity, making their use challenging for healthcare applications where monitoring must continue uninterrupted for a long time, without the need to charge or change the battery. Fog computing can alleviate this problem by offloading computationally intensive tasks from the sensor layer to higher layers, thereby not only meeting the sensors’ limited computational capacity but also enabling the use of local closed-loop energy optimization algorithms to increase the battery life. Furthermore, the patient’s contextual information - including health and activity status - can be exploited to guide energy optimization algorithms more effectively. By incorporating the patient’s contextual information, a desired quality of experience can be achieved by creating a dynamic balance between energy-efficiency and measurement accuracy. We present a runtime distributed control-based solution to find the most energy-efficient system state for a given context while keeping the accuracy of the decision-making process over a certain threshold. Our optimization algorithm resides in the fog layer to avoid imposing computational overheads to the sensor layer. Our solution can be extended to reduce the probability of errors in the data collection process to ensure the accuracy of the results. The implementation of our fog-assisted control solution on a remote monitoring system shows a significant improvement in energy efficiency with a bounded loss in accuracy.

The problem of state tracking with active observation control is considered for a system modeled by a discrete-time, finite-state Markov chain observed through conditionally Gaussian measurement vectors. The measurement model statistics are shaped by the underlying state and an exogenous control input, which influence the observations' quality. Exploiting an innovations approach, an approximate minimum mean-squared error (MMSE) filter is derived to estimate the Markov chain system state. To optimize the control strategy, the associated mean-squared error is used as an optimization criterion in a partially observable Markov decision process formulation. A stochastic dynamic programming algorithm is proposed to solve for the optimal solution. To enhance the quality of system state estimates, approximate MMSE smoothing estimators are also derived. Finally, the performance of the proposed framework is illustrated on the problem of physical activity detection in wireless body sensing networks. The power of the proposed framework lies within its ability to accommodate a broad spectrum of active classification applications, including sensor management for object classification and tracking, estimation of sparse signals, and radar scheduling.

This paper introduces a novel technique for access by a cognitive Secondary User (SU) using best-effort transmission to a spectrum with an incumbent Primary User (PU), which uses Type-I Hybrid ARQ. The technique leverages the primary ARQ protocol to perform Interference Cancellation (IC) at the SU receiver (SUrx). Two IC mechanisms that work in concert are introduced: Forward IC, where SUrx, after decoding the PU message, cancels its interference in the (possible) following PU retransmissions of the same message, to improve the SU throughput; Backward IC, where SUrx performs IC on previous SU transmissions, whose decoding failed due to severe PU interference. Secondary access policies are designed that determine the secondary access probability in each state of the network so as to maximize the average long-term SU throughput by opportunistically leveraging IC, while causing bounded average long-term PU throughput degradation and SU power expenditure. It is proved that the optimal policy prescribes that the SU prioritizes its access in the states where SUrx knows the PU message, thus enabling IC. An algorithm is provided to optimally allocate additional secondary access opportunities in the states where the PU message is unknown. Numerical results are shown to assess the throughput gain provided by the proposed techniques. © 1983-2012 IEEE.

A longitudinal study analyzed (a) which lower- and higher-level semantic components uniquely predicted listening text comprehension and (b) the nature of the relation (i.e., direct and indirect) between the predictors and listening text comprehension in preschoolers. One-hundred and fifty-two children participated in the present study (68 females; mean age = 4;10 years/months and 5;5 years/months at Time 1 and Time 2, respectively). Participants were administered measures to evaluate listening text comprehension (Time 1 and Time 2) and (a) expressive and receptive word knowledge (lower-level semantic components), and (b) inferential skills and the ability to use context (higher-level semantic components) (Time 1). Verbal short-term and working memory were also included as control variables. Data were analyzed using path analysis models. Results showed that both types of semantic components (a) accounted for unique variance in listening text comprehension at Time 2, with lower-level semantic components explaining a larger proportion of variance than higher-level semantic components; (b) were related to later listening text comprehension through direct and indirect relations. Memory resources did not significantly contribute to listening text comprehension. The results are discussed in light of their theoretical relevance and educational/practical implications.

Two studies explored the relation between listening comprehension of text and listening comprehension of sentences in preschoolers aged 4 to 5 years, 11 months. The first study analyzed this relationship taking into account the role of lower level components, namely, word knowledge and verbal working memory, as possible mediators. These components specifically accounted for listening text comprehension, whereas sentence comprehension did not. Given that sentences forming a text are not processed in isolation but in context, the second study explored the role of the ability to use linguistic context, a higher level component, in listening comprehension of text and sentences. Listening sentence comprehension was facilitated by the use of context, which accounted for individual differences in listening text comprehension. Overall, results showed that listening text comprehension is related to lower level as well as higher level components, whereas listening sentence comprehension does not play a specific role.

The current study was designed to investigate the role played by verbal memory in the advantage shown by individuals with Down syndrome in reading over listening text comprehension (Roch & Levorato, 2009). Two different aspects of verbal memory were analyzed: processing load and coding modality. Participants were 20 individuals with Down syndrome, aged between 11 and 26 years who were matched for reading comprehension with a group of 20 typically developing children aged between 6;3 and 7;3 years. The two groups were presented with a listening comprehension test and four verbal memory tasks in which the degree of processing load and the coding modality were manipulated. The results of the study confirmed the advantage of reading over listening comprehension for individuals with Down syndrome. Furthermore, it emerged that different aspects of verbal memory were related respectively to reading and to listening comprehension: visual memory with low processing load was related to the former and oral memory with high processing load to the latter. Finally, it was demonstrated that verbal memory contributed to explain the advantage of reading over listening comprehension in Down syndrome. The results are discussed in light of their theoretical relevance and practical implications. (Contains 4 tables.)

According to multicomponent models (Oakhill & Cain, 2007a), text comprehension is a complex process that requires the processing of explicit (i.e., information presented in the text) and implicit information (i.e., information inferable from the text or from previous knowledge), and involves various components. This study investigated (a) preschoolers' understanding of explicit and implicit information in oral texts and (b) the role of verbal and inferential skills in the processing of explicit and implicit information. Two hundred twenty-one 4- to 6-year-olds were evaluated as to their listening text comprehension and the following components: receptive vocabulary, verbal intelligence, and inferential skills. Working memory was a control variable. Results showed that (a) explicit information was easier to process than implicit information; and (b) all the components considered, except receptive vocabulary, accounted for comprehension of both types of information, and their role was stable in the age range considered. (Contains 1 footnote and 3 tables.)

The contribution of lower level linguistic abilities (study 1) and a higher level capacity, namely the use of context, (study 2), on text comprehension was studied. Participants were 16 individuals with Down syndrome aged between aged between 8 years 11 months and 16 years 10 months, and 16 children with typical development, aged between 5 years 11 months and 7 years 3 months, matched for the level of text comprehension. In study 1 the two groups were compared for receptive vocabulary and sentence comprehension: both of them were shown to play a role in text comprehension in Down syndrome. Since participants with Down syndrome had very low scores in sentence comprehension, study 2 tested the hypothesis that when sentences were presented within a brief context, individuals with Down syndrome would perform better. This hypothesis was confirmed and it was shown that contextual facilitation was closely related to text comprehension skills. (Contains 3 notes, 2 tables and 1 figure.)

Background: According to the "Simple View of Reading" (Hoover and Gough 1990), individual differences in reading comprehension are accounted for by decoding skills and listening comprehension, each of which makes a unique and specific contribution. Aims: The current research was aimed at testing the Simple View of Reading in individuals with Down's syndrome and comparing their profiles with typically developing first graders. Methods & Procedures: Listening comprehension and the ability to read both words and non-words was compared in two groups with the same level of reading comprehension: 23 individuals with Down's syndrome aged between 11 years 3 months and 18 years 2 months and 23 first-grade typically developing children aged between 6 years 2 months and 7 years 4 months. Outcomes & Results: The results indicate that at the same level of reading comprehension, individuals with Down's syndrome have less developed listening comprehension and more advanced word recognition than typically developing first graders. A comparison of the profiles of the two groups revealed that reading comprehension level was predicted by listening comprehension in both groups of participants and by word-reading skills only in typically developing children. Conclusions & Implications: The Simple View of Reading model is confirmed for individuals with Down's syndrome, although they do not show the reading profile of typically developing first graders; rather, they show an atypical profile similar to that of "poor comprehenders" (Cain and Oakhill 2006). The crucial role of listening comprehension in Down's syndrome is also discussed with reference to the educational implications. (Contains 4 tables, 2 figures and 1 note.)

The relation between text and idiom comprehension in children with poor text comprehension skills was investigated longitudinally. In the first phase of the study, six-year-old first graders with different levels of text comprehension were compared in an idiom and sentence comprehension task. Text comprehension was shown to be more closely related to idiom comprehension than sentence comprehension. The follow-up study, carried out eight months later on less-skilled text comprehenders, investigated whether an improvement in text comprehension was paralleled by an improvement in idiom comprehension. The development of sentence comprehension was also taken into account. Children who improved in text comprehension also improved in idiom comprehension; this improvement was, instead, weakly related to an improvement in sentence comprehension. The relationship between text and idiom comprehension is discussed in the light of the Global Elaboration Model (Levorato & Cacciari, 1995).

According to a developmental model of figurative language acquisition--the "global elaboration model" (Levorato & Cacciari, 1995)--the metalinguistic awareness necessary to use figurative language in a creative way is acquired late, and is subsequent to the ability to comprehend and produce figurative expressions. One hundred and eight children aged 9;6, one hundred and twenty-four children aged 11;3, one hundred and twelve adolescents aged 18;5 and one hundred adults participated in Experiment 1 which studied the development of metalinguistic awareness through an elicitation task. The subjects produced a high percentage of figurative expressions with a clear developmental trend that is concluded in adolescence. In addition, Experiment 2 showed that the production of comprehensible, appropriate and novel metaphors, as they were rated by adult judges, also increased with age. These results show that the ability to use figurative language in a creative and sensible way requires a long developmental time span and is strictly connected with the ability to reflect on language as a complex cognitive and interpersonal phenomenon. [This research was supported by a grant from the National Council for Research.]

Investigates whether children's representations of the linguistic description of a goal-directed event was similar to their representation of the same event observed visually. Finds that mode of presentation did not affect the recall of most important actions, but that verbal description led to recall characterized by greater cohesion than visual presentation of the same event. (SR)

Presents a study of the acquisition and development of information coordination ability. Examines students' composition of texts comparing two cultural groups after reading either one text describing both or a separate text on each. Concludes that older students used more complex information integration levels, whereas all subjects performed better when presented with the single text. (DK)