Mathematical Approaches in Functional Safety Assessment for E/E/PE Safety-Related Software

Safety integrity level (SIL)-based functional safety assessment is widely required in designing safety functions and checking their validity of electrical/electronic/programmable electronic (E/E/PE) safety-related systems after being issued IEC 61508 in 2010. For the hardware of E/E/PE safety-related systems, quantitative functional safety assessment based on target failure measures is needed for deciding or allocating the level of SIL. On the other hand, IEC 61508 does not provide any quantitative safety assessment method for allocating SIL for the software of E/E/PE safety-related systems because the software failure is treated as a systematic failure in IEC 61508. We discuss the needfulness of quantitative safety assessment for software of E/E/PE safety-related systems and propose mathematical fundamentals for conducting quantitative SIL-based safety assessment for the software of E/E/PE safety-related systems by applying the notion of software reliability modeling and assessment technologies. We show numerical examples for explaining how to use our approaches.

Analyzing business-failure-process risk: evidence from Finland

Purpose The purpose of this study is to analyze the business-failure-process risk from two perspectives. First, a simplified model of the loss-generation process in a failing firm is developed to show that the linear system embedded in accounting makes financial ratios to depend linearly on each other. Second, a simplified model of the development of the risk during the failure process is developed to introduce a new concept of failure-process-risk line (FPRL) to assess the systematic failure risk of a firm. Empirical evidence from Finnish firms is used to test two hypotheses. Design/methodology/approach This study makes use of simple mathematical modeling to depict the loss-generation process and the development of failure risk during the failure process. Hypotheses are extracted from the mathematical results for empirical testing. Time-series data originally from 13,082 non-failing and 515 failing Finnish are used to test the hypotheses. Analysis of variance F statistics and Mann–Whitney U test are used in testing of the hypotheses. Findings The findings show that the linear time-series correlations are generally higher in failing than in non-failing firms because of the loss-generation process. The FPRL depicted efficiently the systematic failure-process risk through the beta coefficient. Beta coefficient efficiently discriminated between failing and non-failing firms. The difference between the last-period risk estimate and FPRL was largely determined by the approximated growth rate of the periodic failure risk. Research limitations/implications The loss-generation process is based on a simple cash-based approach ignoring the growth of the firm. In future research, the model could be generalized to a growing firm in an accrual-based framework. The failure-process risk is assumed to grow at a constant rate. In further studies, more general models could be applied. Empirical analyses are based on simple statistical methods and tests. More advanced methods could be used to analyze the data. Practical implications This study shows that failure process makes the time-series correlation between financial ratios to increase making their signals of failure consistent and allowing the use of static classification models to assess failure risk. The beta coefficient is a useful tool to reflect systematic failure-process risk. In addition, it can be used in practice to warn a firm about ongoing failure process. Originality/value To the best of the author’s knowledge, this is the first study analyzing systematically business-failure-process risk. It is first in introducing a mathematical loss-generation process and the FPRL based on the beta coefficient assessing the systematic failure risk.

Apocalypse Now or Overreaction to Coronavirus: The Global Cruise Tourism Industry Crisis

The current COVID-19 cruise tourism crisis has evolved to epic proportions and placed some of the cruise lines on the verge of bankruptcy. This research aimed to gain a deeper understanding of the crisis. Using an inductive qualitative approach, interviews were conducted with eight frequent cruisers who were at home and eight cruise ship employees who were employed by various cruise companies and who were working on cruise ships during the COVID-19 cruise tourism crisis. The findings revealed a systematic failure within the cruise industry management to understand the COVID-19 pandemic. Results of this study highlight the importance of health-related perceived risks on the nature and impact of the COVID-19 cruise tourism crisis. This study supports the overall theory of cruise tourism and crisis management by extending the chaos theory and its principals on the COVID-19 cruise tourism crisis. The managerial implications for cruise lines are outlined.

The Yemen Armed Conflict in the Perspective of International Humanitarian Law

Since the Arab Spring, Yemen became the center of worst humanitarian crisis in modern history. This paper investigates the fundamental causes of the current conflict in Yemen and also explicates the legal dimension of International humanitarian law. Political marginalization, social disenfranchisement, economic collapse, the failure of the Yemeni government to address and resolve the socioeconomic frustration of ordinary citizens and corrupt leaders are few reasons which led to the brutal civil war in Yemen. This systematic failure of government and intervention of regional players for their dominance and ascendency created political uprising, violence, and institutional collapse. Thousands of civilians have died, millions of people had been displaced and millions are on the brink of starvation. Several solutions were proposed by introducing the federal system, decentralization of state's power, improving basic infrastructure, negotiations with Houthis but none of these reforms implemented properly. This paper also scrutinized the intervention of regional actors in this ferocious conflict and how regional and international actors violated International Humanitarian law.

The macroeconomic projections of the German government: A comparison to an independent forecasting institution

This paper investigates the macroeconomic projections of the German government since the 1970s and compares it to those of the Joint Economic Forecast, which is an independent forecasting institution in Germany. Our results indicate that both nominal GDP projections are upward biased for longer forecast horizons, which seems to be driven by a false assessment of the decline in Germany’s trend growth and a systematic failure to correctly anticipate recessions. Furthermore, we show that the German government deviates from the projections of the Joint Economic Forecast, which in fact worsened the forecast accuracy. Finally, we find evidence that these deviations are driven by political motives.

Strengthening Hollow Core Concrete Bridges with Deficient Transverse Hinge Joints with a Steel and Concrete Composite Anchorage System

Hollow core concrete bridges have been widely constructed in China during the last two decades. The most simple span bridges, with standard lengths of 13 m, 16 m and 20 m, are hollow core concrete bridges. For this type of bridge, the hollow core slabs are precast and simply lifted into place. After the prefabricated hollow core slabs are put in place, the embedded rebars extending from the prefabricated slabs are bound together and the concrete is poured into the space between the slabs, forming a lateral hinge joints between the slabs. A lot of hollow core concrete bridges built early in the 1990s have small hinge joints and very few rebars embedded to form strong lateral connections between the slabs. With an increase of overweight vehicles and the continuous aging of the structures, structural deficiencies such as intensive cracks running through the mid-span and severe deflection progress rapidly resulting in loss of structural capacity and even collapse. The failure of hollow core concrete bridges usually initiates from the failure of the hinge joints, which are the weakest links of the system. When the hinge joints start to lose their ability to hold the adjacent slabs securely, more and more vehicle loads are shifted onto the slabs with deficient hinge joints, which worsens the condition of the slabs and eventually results in systematic failure. To save the hollow core concrete bridges from failure, the authors propose an effective strengthening method to stop the progress of the deficiencies and improve the capacity of the structure.