Optimized query routing trees for wireless sensor networks

In order to process continuous queries over Wireless Sensor Networks (WSNs), sensors are typically organized in a Query Routing Tree (denoted as T) that provides each sensor with a path over which query results can be transmitted to the querying node. We found that current methods deployed in predominant data acquisition systems construct T in a sub-optimal manner which leads to significant waste of energy. In particular, since T is constructed in an ad hoc manner there is no guarantee that a given query workload will be distributed equally among all sensors. That leads to data collisions which represent a major source of energy waste. Additionally, current methods only provide a topological-based method, rather than a query-based method, to define the interval during which a sensing device should enable its transceiver in order to collect the query results from its children. We found that this imposes an order of magnitude increase in energy consumption.     

A new performance metric for M-APSK receivers

Synchronization is a critical function that determines the overall performance and complexity of the receiver of any communications system. The implementation and evaluation of effective synchronization algorithms still comprises a challenging task that requires accurate testing methods, which are based on measurements collected at various processing stages. M-ary Amplitude-Phase Shift Keying (M-APSK) constellations are used in modern communications systems, such as digital video broadcasting and interactive broadband satellite services, due to their bandwidth efficiency characteristics. This paper presents a new metric that can be associated with the signal quality at various synchronization mechanisms used in M-APSK receivers. Apart from the metric's mathematical derivation, the paper presents various experimental results based on single (QPSK, 8PSK), two (16APSK) and three (32APSK) ring M-APSK schemes employed in DVB-S2 systems.     

Biomolecular and Genetic Prognostic Factors That Can Facilitate Fertility-Sparing Treatment (FST) Decision Making in Early Stage Endometrial Cancer (ES-EC): A Systematic Review

Endometrial cancer occurs in up to 29% of women before 40 years of age. Seventy percent of these patients are nulliparous at the time. Decision making regarding fertility preservation in early stage endometrial cancer (ES-EC) is, therefore, a big challenge since the decision between the risk of cancer progression and a chance to parenthood needs to be made. Sixty-two percent of women with complete remission of ES-EC after fertility-sparing treatment (FST) report to have a pregnancy wish which, if not for FST, they would not be able to fulfil. The aim of this review was to identify and summarise the currently established biomolecular and genetic prognostic factors that can facilitate decision making for FST in ES-EC. A comprehensive search strategy was carried out across four databases; Cochrane, Embase, MEDLINE, and PubMed; they were searched between March 1946 and 22nd December 2022. Thirty-four studies were included in this study which was conducted in line with the PRISMA criteria checklist. The final 34 articles encompassed 9165 patients. The studies were assessed using the Critical Appraisal Skills Program (CASP). PTEN and POLE alterations we found to be good prognostic factors of ES-EC, favouring FST. MSI, CTNNB1, and K-RAS alterations were found to be fair prognostic factors of ES-EC, favouring FST but carrying a risk of recurrence. PIK3CA, HER2, ARID1A, P53, L1CAM, and FGFR2 were found to be poor prognostic factors of ES-EC and therefore do not favour FST. Clinical trials with bigger cohorts are needed to further validate the fair genetic prognostic factors. Using the aforementioned good and poor genetic prognostic factors, we can make more confident decisions on FST in ES-EC.     

Assessment of Performance of Seismic Isolation System of Bolu Viaduct

The Bolu viaduct is a 2.3-km-long seismically isolated structure that was nearly complete when it was struck by the 1999 Duzce earthquake in Turkey. It suffered complete failure of the seismic isolation system and narrowly avoided total collapse due to excessive superstructure movement. This paper presents an evaluation of the design of the viaduct’s seismic isolation system and an assessment of its performance in the Duzce earthquake. Evaluation of the seismic isolation system’s design has revealed that it did not meet the requirements of the AASHTO Guide Specifications for Seismic Isolation Design. Analysis of the viaduct with motions scaled in accordance with the AASHTO Guide Specifications resulted in a displacement demand of 820 mm, which is far more than the 210 mm displacement capacity of the existing isolation system. Analysis of the viaduct for a simulated near-fault motion with characteristics consistent with the site conditions resulted in an isolation system displacement demand of 1,400 mm. This indicates that, even if the isolation system had been designed in compliance with the AASHTO, it would have still suffered damage in the earthquake.     

Identification of coating defects in cathodically protected underground pipelines

Coating defects may occur, for many different reasons, at some points on the surface of a cathodically protected structure. These defects behave anodically and may cause strong localized corrosion. It is possible to identify the position of coating defects by using measured values of the electrochemical potential at some points in the electrolyte or on its surface. To achieve this, an inverse BEM‐based genetic algorithm is developed to identify the position of defects in cathodically protected underground pipelines. The formulation is validated through its application to practical problems involving strongly non‐linear polarization curves, infinite electrolytes, unknown number of defects and measurement noise. Copyright © 2003 John Wiley & Sons, Ltd.     

Robust Artificial Neural Networks for Pricing of European Options

The option pricing ability of Robust Artificial Neural Networks optimized with the Huber function is compared against those optimized with Least Squares. Comparison is in respect to pricing European call options on the S&P 500 using daily data for the period April 1998 to August 2001. The analysis is augmented with the use of several historical and implied volatility measures. Implied volatilities are the overall average, and the average per maturity. Beyond the standard neural networks, hybrid networks that directly incorporate information from the parametric model are included in the analysis. It is shown that the artificial neural network models with the use of the Huber function outperform the ones optimized with least squares. JEL Classification: G13, G14     

Applying spatial hydraulic principles to quantify stream habitat

Flow complexity plays an important role in stream ecology. Yet, a paucity of research exists with regard to quantifying flow complexity and relating it to the habitats that aquatic organisms utilize. Here we provide a generalized example of how two‐dimensional (2‐D) numerical hydraulic models and spatial hydraulic metrics can be used to simulate and quantify biologically important flow patterns within streams. A detailed topographic survey, incorporating meso‐scale topographic features (e.g. exposed boulders and bedrock outcrops) is performed for a small urbanized stream. The 2‐D hydraulic model RMA2 is then used to model the flow conditions within the stream reach. Model results demonstrate that the meso‐scale topographic features create highly complex flow patterns of potential biological importance. Recently developed spatial hydraulic metrics, based on hydraulic engineering principles (vorticity, circulation and kinetic energy gradients), are then used to quantify the various types of flow complexity found within the stream reach. In particular, spatial hydraulic metrics are used to quantify the stream reach's overall flow complexity and the flow complexity surrounding three chub mounds. A method for uniquely characterizing circulation zones is then developed and applied to five circulation zones within the study reach. The principles used in performing this study's topographic survey, spatial explicit hydraulic modelling and spatial hydraulic analyses, form a general framework for quantifying flow complexity in any stream. The ways in which using hydraulic models and spatial hydraulic metrics can help establish better habitat suitability criteria and design best management practices for use in stream and catchment area restoration projects is discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

Statistical Uncertainty and the Estimation of Log Law Parameters

It is experimentally demonstrated that fitting the log law to the mean velocity profile in turbulent open-channel flow to determine the friction velocity, roughness length, and zero-plane displacement, can lead to relatively high standard errors in these parameters. It is also demonstrated that this approach, where the log law alone is used to estimate these parameters, may yield values of these parameters that are significantly different from those obtained when the friction velocity is determined independently of the log law. Although the statistical estimation of the three log law parameters from mean velocity data alone is frequently necessary, this procedure can lead to inaccurate and imprecise estimates of these quantities.