Monitoring fatigue cracks in gears

Vibration analysis is the most common means of gear monitoring and diagnostics. Gear vibration is affected by faults but the signal is usually picked up at the case, where it is also affected by the structural response. An appropriate filtering function is therefore proposed to recover the torsional gear vibration from the case vibration signal. The restored gear vibration can then be used with greater confidence than case vibration both for particular diagnostics purposes like crack detection and for more general objectives. This technique and its possible advantages in fatigue crack detection are illustrated in the paper.     

Daily Dialysis: Toward a New Standard in Well‐Being

Daily hemodialysis (DHD) is a promising option; however, logistic obstacles and clinical perplexities limit its dissemination. Understanding the mechanisms of, and the time until, the onset of improved well‐being may help to quantify clinical advantages and to define the minimum length of a “trial” of daily dialysis. By following 30 patients treated in 4 centers, this study aimed to determine how long a period of time is needed until a patient experiences subjective improvement. From November 1998 to November 2000, 30 patients tried at least 2 weeks of short daily dialysis in four Northern Italian centers of Piemonte and Valle d'Aosta. The DHD (2 – 3 hours; blood flow 270 – 350 mL/min; individual HCO₃, Na, K) was performed at home or in a center. Motivations to try DHD, fears and concerns regarding DHD, and changes in perceived well‐being were assessed by semi‐structured interview. The main clinical indications for a trial of DHD were poor tolerance of conventional treatment, cardiovascular disease, and hypertension or hypotension; only 6 patients had no comorbidity at start. The patients' main reasons for choosing DHD were related to job problems and the search for a better treatment. Most of the patients continued DHD because of improved well‐being; logistic reasons accounted for the drop‐outs (5 patients). The main fears were related to logistic aspects, vascular access problems, and excessive involvement of the partner on home dialysis. Improved well‐being was reported by 28 of 30 patients; 2 patients reported no difference. Subjective improvement was perceived within 2 weeks in 22 of 30 patients, and within 1 month in 28 of 30 patients. An offer of a 2 – 4 week trial of DHD may help patients and caregivers to determine whether subjective and objective benefits outweigh logistic problems and whether a permanent transfer to DHD is worthwhile.     

Requirements-driven deployment

Deployment is a main development phase which configures a software to be ready for use in a certain environment. The ultimate goal of deployment is to enable users to achieve their requirements while using the deployed software. However, requirements are not uniform and differ between deployment environments. In one environment, certain requirements could be useless or redundant, thereby making some software functionalities superfluous. In another environment, instead, some requirements could be impossible to achieve and, thus, additional functionalities would be required. We advocate that ensuring fitness between requirements and the system environment is a basic and critical step to achieve a comprehensive deployment process. We propose a tool-supported modelling and analysis approach to tailor a requirements model to each environment in which the system is to be deployed. We study the case of a contextual goal model, which is a requirements model that captures the relationship between the variability of requirements (goal variability space) and the varying states of a deployment environment (context variability space). Our analysis relies on sampling a deployment environment to discover its context variability space and use it to identify loci in the contextual goal model where a modification has to take place. Finally, we apply our approach in practice and report on the obtained results.     

Adaptive socio-technical systems: a requirements-based approach

A socio-technical system (STS) consists of an interplay of humans, organizations, and technical systems. STSs are heterogeneous, dynamic, unpredictable, and weakly controllable. Their operational environment changes unexpectedly, actors join and leave the system at will, actors fail to meet their objectives and under-perform, and dependencies on other actors are violated. To deal with such situations, we propose an architecture for STSs that makes an STS self-reconfigurable, i.e., capable of switching autonomously from one configuration to a better one. Our architecture performs a Monitor-Diagnose-Reconcile-Compensate cycle: it monitors actor behaviors and context changes, diagnoses failures and under-performance by checking whether monitored behavior is compliant with actors goals, finds a possible way to address the problem, and enacts compensation actions to reconcile actual and desired behavior. Compensation actions take into account the autonomy of participants in an STS, which cannot be controlled. Our architecture is requirements driven: we use extended Tropos goal models to diagnose failures as well as to identify alternative strategies to meet requirements. After presenting our conceptual architecture and the algorithms, it is founded upon; we describe a prototype implementation applied to a case study concerning smart-homes. We also provide experimental results that suggest that our architecture scales well as the size of the STS grows.     

Second Cancer Onset in Myeloproliferative Neoplasms: What,When, Why?

The risk of developing a solid cancer is a major issue arising in the disease course of a myeloproliferative neoplasm (MPN). Although the connection between the two diseases has been widely described, the backstage of this complex scenario has still to be explored. Several cellular and molecular mechanisms have been suggested to link the two tumors. Sometimes the MPN is considered to trigger a second cancer but at other times both diseases seem to depend on the same source. Increasing knowledge in recent years has revealed emerging pathways, supporting older, more consolidated theories, but there are still many unresolved issues. Our work aims to present the biological face of the complex clinical scenario in MPN patients developing a second cancer, focusing on the main cellular and molecular pathways linking the two diseases.