Analyzing a controller of a power distribution unit using formal methods

This paper reports on the steps to formally verify the behavior of a controller of a power distribution unit (PDU) using the Analytical Software Design (ASD) method. The controller of the underlying PDU mainly controls the distribution of power and related network messages to a number of attached PCs and devices of X-ray systems. The behavioral correctness of the controller is critical in order to provide the clinical users the expected behavior of the system. As a result of the behavioral verification, two previously unrevealed errors were identified within the design of the PDU controller. According to the development team of the PDU the work has had a major benefit, locating errors that would have been hard to find otherwise by traditional testing

Investigating the effects of designing industrial control software using push and poll strategies

In this paper we apply a number of design guidelines for circumventing the state space explosion problem from [J.F. Groote, T.W.D.M. Kouters, and A.A.H. Osaiweran, Specification guidelines to avoid the state space explosion problem, 2011] to the design and formal verification of a real industrial case, namely a controller of a power distribution unit of X-ray machines developed at Philips Healthcare. Through this work we investigate whether these guidelines are effective in designing practical applications. We provide a number of alternative designs that mainly incorporate pushing and polling strategies, taking into account a number of these guidelines. Using the pushing strategy components notify one another when information becomes available while using polling components ask for information only when it is needed. We find that designs that use a pushing strategy and do not apply such guide-lines typically lead to the generation of substantially more states. All demonstrated designs formally refine a single predefined external specification that captures the desired external behavior of the system. Moreover, all designs are deadlock free and do not exhibit any illegal interactions. This confirms our hypothesis that the design guidelines are really effective in practical contexts

Investigating the effects of designing industrial control software using push and poll strategies

In this paper we apply a number of design guidelines for circumventing the state space explosion problem from [J.F. Groote, T.W.D.M. Kouters, and A.A.H. Osaiweran, Specification guidelines to avoid the state space explosion problem, 2011] to the design and formal verification of a real industrial case, namely a controller of a power distribution unit of X-ray machines developed at Philips Healthcare. Through this work we investigate whether these guidelines are effective in designing practical applications. We provide a number of alternative designs that mainly incorporate pushing and polling strategies, taking into account a number of these guidelines. Using the pushing strategy components notify one another when information becomes available while using polling components ask for information only when it is needed. We find that designs that use a pushing strategy and do not apply such guide-lines typically lead to the generation of substantially more states. All demonstrated designs formally refine a single predefined external specification that captures the desired external behavior of the system. Moreover, all designs are deadlock free and do not exhibit any illegal interactions. This confirms our hypothesis that the design guidelines are really effective in practical contexts

On infrastructure for facilitation of inner source in small development teams

The phenomenon of adopting open source software development practices in a corporate environment is known by many names, one being inner source. The objective of this study is to investigate how an organization consisting of small development teams can benet from adopting inner source and assess the level of applicability. The research has been conducted as a case study at a software development company. Data collection was carried out through interviews and a series of focus group meetings, and then analyzed by mapping it to an available framework. The analysis shows that the organization possesses potential, and also identied a number of challenges and benets of special importance to the case company. To address these challenges, the case study synthesized the organizational and infrastructural needs of the organization in a requirements specication describing a technical infrastructure, also known as a software forge, with an adapted organizational context and work process

ISO Spectroscopy of Young Stellar Objects

Observations of gas-phase and solid-state species toward young stellar objects (YSOs) with the spectrometers on board the Infrared Space Observatory are reviewed. The excitation and abundances of the atoms and molecules are sensitive to the changing physical conditions during star-formation. In the cold outer envelopes around YSOs, interstellar ices contain a significant fraction of the heavy element abundances, in particular oxygen. Different ice phases can be distinguished, and evidence is found for heating and segregation of the ices in more evolved objects. The inner warm envelopes around YSOs are probed through absorption and emission of gas-phase molecules, including CO, CO_2, CH_4 and H_2O. An overview of the wealth of observations on gas-phase H_2O in star-forming regions is presented. Gas/solid ratios are determined, which provide information on the importance of gas-grain chemistry and high temperature gas-phase reactions. The line ratios of molecules such as H_2, CO and H_2O are powerful probes to constrain the physical parameters of the gas. Together with atomic and ionic lines such as [0 I] 63 µm, [S I] 25 µm and (Si II] 35 µm, they can also be used to distinguish between photon- and shock-heated gas. Finally, spectroscopic data on circumstellar disks around young stars are mentioned. The results are discussed in the context of the physical and chemical evolution of YSOs

Software quality control and software requirements specification

Electrical Engineering, Mathematics and Computer Scienc

Analyzing the effects of formal methods on the development of industrial control software

Formal methods are being applied to the development of software of various applications at Philips Healthcare. In particular, the Analytical Software Design (ASD) method is being used as a formal technology for developing defect-free control software of highly sophisticated X-ray equipments. In this paper we analyze the effects of applying ASD to the development of various control software units developed for the X-ray machines. We compare the quality of these units with other units developed in traditional development methods. The results indicate that applying ASD as a formal technology for developing control software could result in fewer defects

Incorporating formal techniques into industrial practice : an experience report

We report about experiences at Philips Healthcare with component-based development supported by formal techniques. The formal Analytical Software Design (ASD) approach of the company Verum has been incorporated into the industrial workflow. The commercial tool ASD:Suite supports both compositional verification and code generation for control components. For other components test-driven development has been used. We discuss the results of these combined techniques in a project which developed the power control service of an interventional X-ray system

Psychological distress and health-related quality of life in patients after hospitalization during the COVID-19 pandemic

Introduction Illnesses requiring hospitalization are known to negatively impact psychological well-being and health-related quality of life (HRQoL) after discharge. The impact of hospitalization during the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) pandemic on psychological well-being and health-related quality of life is expected to be higher due to the exceptional circumstances within and outside the hospital during the pandemic surge. The objective of this study was to quantify psychological distress up to three months after discharge in patients hospitalized during the first coronavirus diseas

Psychological distress and health-related quality of life in patients after hospitalization during the COVID-19 pandemic

Introduction Illnesses requiring hospitalization are known to negatively impact psychological well-being and health-related quality of life (HRQoL) after discharge. The impact of hospitalization during the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) pandemic on psychological well-being and health-related quality of life is expected to be higher due to the exceptional circumstances within and outside the hospital during the pandemic surge. The objective of this study was to quantify psychological distress up to three months after discharge in patients hospitalized during the first coronavirus diseas