A review on queueing network models with finite capacity queues for software architectures performance prediction

A review is carried out on how queueing network models with blocking have been applied so far into the performance evaluation and prediction of Software Architectures (SA). Queueing network models with finite capacity queues and blocking have recently been introduced and applied as more realistic models of systems with finite capacity resources and population constraints. Queueing network models have been often adopted as models for the evaluation of software performance. Starting from our own experience, we observe the need of a more accurate definition of the performance models of SA to capture some features of the communication systems. We consider queueing networks with finite capacity and blocking after service (BAS) to represent some synchronization constraints that cannot be easily modeled with queueing network models with infinite capacity queues. We investigate the use of queueing networks with blocking as performance models of SA with concurrent components and synchronous communication. Queueing theoretic analysis is used to solve the queueing network model and study the synchronous communication and performance of concurrent software components. Our experience is supported by other approaches that also propose the use of queueing networks with blocking. Directions for future research work in the field are included.     

Out-of-Field Hippocampus from Partial-Body Irradiated Mice Displays Changes in Multi-Omics Profile and Defects in Neurogenesis

The brain undergoes ionizing radiation exposure in many clinical situations, particularly during radiotherapy for brain tumors. The critical role of the hippocampus in the pathogenesis of radiation-induced neurocognitive dysfunction is well recognized. The goal of this study is to test the potential contribution of non-targeted effects in the detrimental response of the hippocampus to irradiation and to elucidate the mechanisms involved. C57Bl/6 mice were whole body (WBI) or partial body (PBI) irradiated with 0.1 or 2.0 Gy of X-rays or sham irradiated. PBI consisted of the exposure of the lower third of the mouse body, whilst the upper two thirds were shielded. Hippocampi were collected 15 days or 6 months post-irradiation and a multi-omics approach was adopted to assess the molecular changes in non-coding RNAs, proteins and metabolic levels, as well as histological changes in the rate of hippocampal neurogenesis. Notably, at 2.0 Gy the pattern of early molecular and histopathological changes induced in the hippocampus at 15 days following PBI were similar in quality and quantity to the effects induced by WBI, thus providing a proof of principle of the existence of out-of-target radiation response in the hippocampus of conventional mice. We detected major alterations in DAG/IP3 and TGF-β signaling pathways as well as in the expression of proteins involved in the regulation of long-term neuronal synaptic plasticity and synapse organization, coupled with defects in neural stem cells self-renewal in the hippocampal dentate gyrus. However, compared to the persistence of the WBI effects, most of the PBI effects were only transient and tended to decrease at 6 months post-irradiation, indicating important mechanistic difference. On the contrary, at low dose we identified a progressive accumulation of molecular defects that tended to manifest at later post-irradiation times. These data, indicating that both targeted and non-targeted radiation effects might contribute to the pathogenesis of hippocampal radiation-damage, have general implications for human health.     

Access of the substrate to the active site of yeast oxidosqualene cyclase: an inhibition and site-directed mutagenesis approach

A structural model of Saccharomyces cerevisiae oxidosqualene cyclase (SceOSC) suggests that some residues of the conserved sequence Pro-Ala-Glu-Val-Phe-Gly (residues 524-529) belong to a channel constriction that gives access to the active-site cavity. Starting from the SceOSC C457D mutant, which lacks the cysteine residue next to the catalytic Asp456 residue Cys457 has been replaced but Asp456 is still there, we prepared two further mutants where the wild-type residues Ala525 and Glu526 were individually replaced by cysteine. These mutants, especially E526C, were very sensitive to the thiol-reacting agent dodecyl-maleimide. Moreover, both the specific activity and the thermal stability of E526C were severely reduced. A similar decrease of the enzyme functionality was obtained by replacing Glu526 with alanine, while substitution with the conservative residues aspartate or glutamine did not alter catalytic activity. Molecular modeling of the yeast wild-type OSC and mutants on the template structure of human OSC confirms that the channel constriction is an important aspect of the protein structure and suggests a critical structural role for Glu526.     

Routing and resource optimization in service overlay networks

Service Overlay Networks (SONs) create a virtual topology on top of the Internet and provide end-to-end quality of service guarantees without requiring support by the underlying network.The optimization of the resources utilized by an SON is a fundamental issue for an overlay operator owing to the costs involved and the need to satisfy user requirements. Careful decisions are necessary to provide enough capacity to overlay links, to route traffic, to assign users to access nodes and to deploy overlay nodes.In this paper, we propose two mathematical programming models for the user assignment problem, the traffic routing optimization and the dimensioning of the capacity reserved on overlay links in SONs. The first model minimizes the SON installation cost while providing full access to all users. The second model maximizes the SON profit by selecting which users to serve, based on the expected gain, and taking into consideration budget constraints of the SON operator. Moreover, we extend these models to include the optimization of the number and position of overlay nodes.We provide the optimal solutions of the proposed SON design formulations on a set of realistic-size instances and discuss the effect of different parameters on the characteristics of the planned networks. Numerical results show that the proposed approach is able to solve the problem to the optimum even for large-scale networks.     

The joint Gateway Placement and Spatial Reuse Problem in Wireless Mesh Networks

A Wireless Mesh Network (WMN) is composed of multiple Access Points (APs) that are connected together using the radio channel and by a limited number of gateway APs connected to the Internet. In this paper, we address the problem of gateway placement that consists of minimizing the number of gateways while satisfying system performance requirements. Along with the placement problem, the formulation includes joint routing and scheduling to account for the problem of interference and to enable spacial reuse. The problem, which we coined GPSRP (Gateway Placement and Spatial Reuse Problem), allows a much more efficient use of the available resources and reduces overall gateway costs. This article presents for the first time a mathematical formulation of the problem and discusses its advantages and limitations with respect to other approaches.     

ROMANSEVAL: Results for Italian by SENSE

The paper describes SENSE, a word sense disambiguation system thatmakes use of different types of cues to infer the most likelysense of a word given its context. Architecture and functioning ofthe system are briefly illustrated. Results are given for theROMANSEVAL Italian test corpus of verbs.     

Reversible Fragmentation and Self‐Assembling of Nematic Liquid Crystal Droplets on Functionalized Pyroelectric Substrates

Investigation on the behavior of nematic liquid crystals on functionalized polar dielectric crystal substrates is accomplished. Very interesting effects can be observed in maneuvering liquid crystal droplets on the substrate surface, driven by electric fields generated by pyroelectric effect. Reversible drops fragmentation and self‐assembling in different configurations can be achieved. The dynamics of the observed phenomena is studied and the repeatability of the process is full assessed.     

A framework for home energy management and its experimental validation

With the Smart Grid revolution and the increasing interest in renewable energy sources, the management of the electricity consumption and production of individual households and small residential communities is becoming an essential element of new power systems. The electric energy chain can greatly benefit from a flexible interaction with end-users based on the optimization of load profiles and the exploitation of local generation and energy storage. This paper proposes a framework for the development of a complete energy management system for individual residential units and small communities of domestic users, taking into account both the power system and the final users’ perspectives. All the main elements of the framework are considered, and contributions are provided on the users’ habits profiling, electricity generation forecast, energy load, and storage optimization. Specifically, we propose a linear regression model to predict the photovoltaic panels production, a stochastic method to forecast the home appliances usage, and two optimization models to optimize the electricity management of residential users with the goal of minimizing their bills. The study shows that it is possible to reduce the energy bill of residential users through the electricity optimization driven by dynamic energy prices. Moreover, remarkable improvements of the electric grid efficiency can be achieved with the cooperation among users, confirming that services for the coordination of the demand of groups of users allow huge benefits on the power system performance.     

Radio planning of energy-aware cellular networks

This paper introduces a joint planning and management optimization approach for cellular networks to limit energy consumption while guaranteeing QoS and minimizing operators Capex and Opex. The modeling framework shows that an effective energy-efficient operation depends on the planning decisions. Conversely, it also shows that planning with energy management operation in view yields more versatile topologies than more traditional models based only on Capex. Results for LTE networks are provided and show that savings up to 65% in energy expenses are possible with slight increases in capital investments.     

A signature protein-based method to distinguish Mediterranean water buffalo and foreign breed milk

A novel genetic variant at the α_s1-casein locus of water buffalo (WB), 8-residue shorter than its wild-type has been found and sequenced. The internal deletion of the peptide E³⁵KVNELsT⁴² was confirmed by the isolation of the junction peptide. The 8-residue deletion mutant has a molecular weight that is 919 Da less than that of the wild-type. The novel isoform with a unique f35-42 deletion could be the result of the skipping of exon 6, generating an exon 6-deleted variant of α_s1-casein. The wild-type and its shortened α_s1-casein forms were found to co-exist in many individual milk samples. In contrast, the 8-residue, internally deleted α_s1-casein variant did not occur in water buffaloes of the Mediterranean breed reared in Italy. Wild-type α_s1-casein has 6 to 8 phosphate groups (P) while the internally deleted form 6 and 7P per molecule.