Hellenic Navy

Bathymetric data are crucial for benthic monitoring in coastal areas but are traditionally obtained through costly and geographically limited acoustic methods. This study uses satellite-derived bathymetry (SDB) in the Eastern Mediterranean, focusing on the Cretan Sea in Greece. It explores how variations in water surface optical properties affect SDB models over four years (2019–2022), using Sentinel-2 satellite data. The research covers two areas with contrasting features: the Chania Gulf and the open waters around Chrissi Island. Three methodologies were tested: the band-ratio method, the linear-logarithmic method, and an inherent optical properties linear model. Significant spatiotemporal variations in the SDB models were found, due to seasonal changes in water surface properties, such as temperature and suspended organic materials. Linear optical properties-based methods performed best, achieving a mean RMSE close to 1 m, slightly outperforming the ratio-based method. The logarithmic method was less effective, with RMSE values ranging from 1.3 to 1.5 m. A preliminary Kalman filter (KF) analysis increased RMSE to the decimeter level. This study demonstrates the impact of water surface optical properties on SDB models. It highlights the value of SDB for cost-effective, high-resolution coastal mapping in complex coastlines like those in Greece.

We develop a theoretical framework that extends the Bernanke and Blinder model to incorporate imperfect substitution between internal and external finance of firms to study the operation of both the bank lending and the balance sheet channels of monetary transmission in the US. Our model is used to quantify the financial accelerator effects due to the operation of these channels. Empirically, we use multivariate cointegration techniques to identify the equilibrium relationships included in our model, and we provide evidence that only the balance sheet channel is operational for the period before and after the global financial crisis.

The maritime sector is a vital component of the global economy. Its international nature supersedes state boundaries and any disruption in its operations could have consequent and collateral global effects, affecting the socio-economic wellbeing of regions, states and peoples. The increasing adoption of digitalisation in the sector, primarily increases efficiency, minimize cost and maximise benefit, while improving safety, simultaneously introduces a new cyber threat landscape. The attack surface has broadened further due to the COVID-19 pandemic, as recent, high-profile cyber attacks to shipping companies have indicated. Cybersecurity is not limited to technology but involves people and business processes. Hence, to mitigate the security risk introduced by cyber threat actors, the industry, like any other, should initially focus on identifying its most critical assets and then adopt risk mitigation measures, spreading from legislative initiatives to company-specific technology solutions. Industry-led initiatives should promote the adoption of cyber-related policies and mechanisms that focus on business continuity. It should be the role of international bodies, classification societies and national authorities to ensure compliance and full implementation of these measures. This paper adopts a System of Systems Analysis to carry out a vulnerability assessment of port and ship ecosystem, while providing insights on the role of the aforementioned entities. Our analysis decomposes the industry’s major assets; ports and ships, to specific subcomponents which are used as the basis of the vulnerability assessment. According to our findings, this approach highlights that the majority of these subcomponents; ports and ships, are increasingly vulnerable to cyber attacks.

Every year, marine scientists around the world read thousands of otolith or scale images to determine the age structure of commercial fish stocks. This knowledge is important for fisheries and conservation management. However, the age-reading procedure is time-consuming and costly to perform due to the specialized expertise and labor needed to identify annual growth zones in otoliths. Effective automated systems are needed to increase throughput and reduce cost. DeepOtolith (http://otoliths.ath.hcmr.gr/) is an open-source artificial intelligence (AI) platform that addresses this issue by providing a web system with a simple interface that automatically estimates fish age by combining otolith images with convolutional neural networks (CNNs), a class of deep neural networks that has been a dominant method in computer vision tasks. Users can upload otolith image data for selective fish species, and the platform returns age estimates. The estimates of multiple images can be exported to conduct conclusions or further age-related research. DeepOtolith currently contains classifiers/regressors for three fish species; however, more species will be included as related work on ageing will be tested and published soon. Herein, the architecture and functionality of the platform are presented. Current limitations and future directions are also discussed. Overall, DeepOtolith should be considered as the first step towards building a community of marine ecologists, machine learning experts, and stakeholders that will collaborate to support the conservation of fishery resources.

According to the World Health Organization (WHO) cancer is the second leading cause of death worldwide and accounts for approximately 9.6 million deaths in 2018. Pain is particularly common and extremely worrying for these patients, especially in metastases. Such a situation imposes an approach that would improve the quality of life and would provide specialized medical care which is, according to WHO, the definition of Palliative Care. There have been many efforts to recognize and establish the human right of pain relief, in order to promote the enforcement of human dignity and the protection of Public Health. However, from the thorough study of the literature on this subject, it emerges that much more could be done in that direction. There is a lag firstly in health policy making to prevent and adopt palliative care in health care and health systems. Secondly, there is also a lag in continuing education of health professionals in the treatment and management of pain, and the information of patients and their relatives about their rights. Another obstacle is the problem in opioid accessibility, that are in the treatment of pain, and finally there are social, cultural and economic problems that are to be resolved. Relief from pain, especially in patients with end-stage cancer, is a major public health and community issue. Good cooperation of all (health scientists, scientists, patients, relatives, governments, international organizations) and the exchange of knowledge and information can overall bring very important changes that would go beyond any obstacles and would bring us one step closer to conquering the relief from pain at the end of life.

This paper presents a user-friendly design method for accurately sizing the distributed energy resources of a stand-alone microgrid to meet the critical load demands of a military, commercial, industrial, or residential facility when utility power is not available. The microgrid combines renewable resources such as photovoltaics (PV) with an energy-storage system to increase energy security for facilities with critical loads. The design method’s novelty complies with IEEE Standards 1562 and 1013, and addresses resilience, which is not taken into account in existing design methods. Several case studies simulated with a physics-based model validate the proposed design method and demonstrate how resilience can be included in the design process. Additionally, the design and the simulations were validated by 24 h laboratory experiments conducted on a microgrid assembled using commercial off-the-shelf components.

The economical and operational implications of poor alignment are indisputable for the propulsion shafting system of a commercial vessel. This holds true for naval vessels as well, although far less documented in the technical literature. This paper addresses some of the challenges associated with the proper alignment of a high-speed naval craft, which has been in service for many years. Laser bore-sighting was performed on a Guided Missile Fast Patrol Boat resting on a docking cradle. The measured bearing offsets were input to a FEA model of the shafting system to calculate bearing reactions and detect potential misalignment issues. Subsequent decisions regarding corrective measures take into account the results computed by the numerical model, experience from sister ships, the available documentation from the building yard and several other factors which are discussed in the paper. The solutions proposed are targeted towards a balanced trade-off between cost effectiveness and out-of-service time on one hand, and the risk of potential damage from misalignment on the other hand, which would seriously disrupt the ship’s operational availability. Practical aspects and lessons identified in the process are also presented, which demonstrate the distinct differences in alignment strategy of a high-speed naval craft compared to a typical commercial vessel.

Although water-based approaches have been shown to be beneficial for children with Autism Spectrum Disorder (ASD), no study thus far has directly investigated the effects of such intervention programs on language skills. The present study aims to evaluate the efficacy of the Aquatic Speech and Language Therapy (ASLT) program, which is a new, exclusively aquatic intervention program designed especially for children with ASD. The effects of ASLT were compared to the outcome of a similar classroom-based intervention, in two groups of children with ASD matched for age, gender, and expressive/receptive vocabulary. Our findings show that ASLT results in significantly greater improvement of vocabulary measures, thus providing direct evidence of water-based intervention’s beneficial effects on language skills in ASD.

There is a relationship between patients with chronic kidney disease and coronary artery disease. These two entities share both common etiologies and risk factors. Management of different patients with coronary artery disease in the aspect of renal insufficiency and certain medications such as contrast media is thus of high importance. Treatment nihilism is a major problem though and healthcare providers must make efforts to maintain a stable kidney function in all coronary artery disease patients. Answer questions and earn CME : https://wileyhealthlearning.com/Activity2/5430077/Activity.aspx

Background FOXG1 gene mutations have been associated with the congenital variant of Rett syndrome (RTT) since the initial description of two patients in 2008. The on-going accumulation of clinical data suggests that the FOXG1-variant of RTT forms a distinguishable phenotype, consisting mainly of postnatal microcephaly, seizures, hypotonia, developmental delay and corpus callosum agenesis. Case presentation We report a 6-month-old female infant, born at 38 weeks of gestation after in vitro fertilization, who presented with feeding difficulties, irritability and developmental delay from the first months of life. Microcephaly with bitemporal narrowing, dyspraxia, poor eye contact and strabismus were also noted. At 10 months, the proband exhibited focal seizures and required valproic acid treatment. Array-Comparative Genomic Hybridization revealed a 4.09 Mb deletion in 14q12 region, encompassing the FOXG1 and NOVA1 genes. The proband presented similar feature with patients with 14q12 deletions except for dysgenesis of corpus callosum. Disruption of the NOVA1 gene which promotes the motor neurons apoptosis has not yet been linked to any human phenotypes and it is uncertain if it affects our patient’s phenotype. Conclusions Since our patient is the first reported case with deletion of both genes (FOXG1-NOVA1), thorough clinical follow up would further delineate the Congenital Rett-Variant phenotypes.

This paper analyzes the impact and benefits resulting from using modern satellite telecommunications in the military. During the last two decades, satellite telecommunications have been considered as the most significant and prioritized tool of information superiority in any operational theatre. As it will be explained, their extensive use encompasses not only the traditional strategic military telecommunications but tactical networks as well. However, their effective and efficient use necessitates the proper evaluation of their capabilities and their limitations. Starting with a brief historical reference, we proceed by considering their advantages, together with modern modulation and networking technologies used to limit their drawbacks. Finally, it will be shown that the most effective approach to exploit their capabilities is to include in a common network architecture all available means of wideband telecommunications, terrestrial and wireless. The idea can be further applied to provide high performance connectivity for a networked sensors C4ISR infrastructure.

Purpose. Family dietary and nutritional behaviors predispose children to obesity. The purpose of this study was to examine the childhood obesity risk among overweight women and to assess feasibility of using a screening tool in a busy clinic setting. Design. A cross-sectional study using the Family Nutrition Physical Activity (FNPA) tool was self-administered by 98 overweight mothers identifying risk factors for childhood obesity. Measures. Mothers completed demographic and a 20-item screening survey with subscales on family meal patterns, family eating habits, food choices, beverage choices, restriction/reward, screen time behavior and monitoring, healthy environment, family activity involvement, child activity involvement, and family routine. After completing the survey, a summary of recommended practices from the American Academy of Pediatrics was provided. Results. Ninety-eight mothers participated (of 172 children between 2 and 18 years old). Lower FNPA scores (obesogenic) were associated were higher body mass index, family income, race/ethnicity, education, and mother's body mass index. Parents' and children's obesity was comparable to what is found in larger populations, whereas obesity in the age-group between 2 and 5 years was doubled. Conclusion. Findings support maternal obesity is significant predictor for the development of child obesity. FNPA identified risk and feasibility of use was demonstrated.

Plane-wave excitation fields are not always sufficient for the immunity characterization of wire-type structures operating in the contemporary manmade environment. Following a previous work dealing with straight-wire transmission lines in the presence of nonuniform fields, the present paper examines twisted-wire pairs. Numerical results for the induced load voltages reveal the importance of field nonuniformity for assessing the immunity behavior of twisted-wire transmission lines on a firmer basis.

The general stress conditions, which dominate in the zone of hydride precipitation under steady state for hydrogen diffusion, are derived, by rigorously taking into account the coupling of the operating physical processes. The conditions are valid, irrespective of metal elastic anisotropy, plastic deformation or geometry. According to these conditions, stress trace is a function only of temperature, leading to loss of dominance of the well-known asymptotic crack-tip stress fields of hydrogen-free metals, including those of constraint-based fracture mechanics. The present analysis is applied to a hydrided cylindrical wall and a hydrided plate under steady state heat conduction. It is shown that a nearly linear variation of hydrostatic stress dominates within the area of hydride precipitation, even in the presence of a surface crack, being in excellent agreement with existing detailed finite element calculations.

Sensitivity-based model error localization and damage detection is hindered by the relative differences in modal sensitivity magnitude among updating parameters. The method of artificial boundary conditions is shown to directly address this limitation, resulting in the increase of the number of updating parameters at which errors can be accurately localized. Using a single set of FRF data collected from a modal test, the artificial boundary conditions (ABC) method identifies experimentally the natural frequencies of a structure under test for a variety of different boundary conditions, without having to physically apply the boundary conditions, hence the term “artificial”. The parameter-specific optimal ABC sets applied to the finite element model will produce increased sensitivities in the updating parameter, yielding accurate error localization and damage detection solutions. A method is developed for identifying the parameter-specific optimal ABC sets for updating or damage detection, and is based on the QR decomposition with column pivoting. Updating solution residuals, such as magnitude error and false error location, are shown to be minimized when the updating parameter set is limited to those corresponding to the QR pivot columns. The existence of an optimal ABC set for a given updating parameter is shown to be dependent on the number of modes used, and hence the method developed provides a systematic determination of the minimum number of modes required for localization in a given updating parameter. These various concepts are demonstrated on a simple model with simulated test data.

Hybrid hard decision-soft decision (HD/SD) decoding is a novel decoding technique for Reed Solomon (RS) codes. HD/SD decoding utilizes traditional hard decision RS decoding where the received block is either decoded correctly or a decoding failure exists. In the event of a decoding failure, channel reliability information is used to identify received code symbols with a low probability of being correctly received and to generate new code symbol estimates that are used in the traditional RS decoding algorithm. HD/SD RS decoding was developed for use with bandwidth efficient modulation schemes such as M-ary phase-shift keying and has been examined only in an additive white Gaussian noise (AWGN) environment. This paper presents the performance simulation and analysis of proposed alternative waveforms for Automatic Link Establishment and the Link-16/Joint Tactical Information Distribution System utilizing orthogonal signaling and Reed Solomon (RS) encoding. The proposed modulation scheme is double-symbol 8-FSK, where two modulation symbols are used to transmit a single RS code symbol, and hybrid HD/SD decoding. In addition to AWGN, the effects of pulse-noise interference (PNI) are considered. An interesting result is that hybrid HD/SD decoding has better performance and error correction capability than either traditional HD decoding or other RS SD techniques that have been examined in the literature, especially when PNI is present. The proposed alternative waveforms provide more robust communication links and increased throughput.

Plane-wave excitation fields are by far the most commonly used in field-to-wire coupling computations. Nevertheless, such excitations are not always adequate for the immunity assessment of wire-type structures operating in the contemporary man-made environment. To reinforce this conjecture, this study examines two-wire transmission lines excited by common non-uniform fields. Numerical results for the induced load voltages show notable deviations from those obtained under the assumption of plane-wave incidence.

In the present article we study, from theoretical point of view, the sick-building syndrome (SBS). We analyse more than 50 symptoms that are reported by those who suffer from the SBS. In addition, the most important factors that lead to the development of SBS are distinguished and we mention the substances that generally seem to cause SBS. Moreover, a model about the prediction and ascertainment of SBS has been proposed. Finally, overall rules for prevention and confrontation of this problem are suggested.