Probabilistic Analysis of Facility Location on Random Shortest Path Metrics

The facility location problem is an NP-hard optimization problem. Therefore, approximation algorithms are often used to solve large instances. Such algorithms often perform much better than worst-case analysis suggests. Therefore, probabilistic analysis is a widely used tool to analyze such algorithms. Most research on probabilistic analysis of NP-hard optimization problems involving metric spaces, such as the facility location problem, has been focused on Euclidean instances, and also instances with independent (random) edge lengths, which are non-metric, have been researched. We would like to extend this knowledge to other, more general, metrics. We investigate the facility location problem using random shortest path metrics. We analyze some probabilistic properties for a simple greedy heuristic which gives a solution to the facility location problem: opening the $\kappa$ cheapest facilities (with $\kappa$ only depending on the facility opening costs). If the facility opening costs are such that $\kappa$ is not too large, then we show that this heuristic is asymptotically optimal. On the other hand, for large values of $\kappa$, the analysis becomes more difficult, and we provide a closed-form expression as upper bound for the expected approximation ratio. In the special case where all facility opening costs are equal this closed-form expression reduces to $O(\sqrt[4]{\ln(n)})$ or $O(1)$ or even $1+o(1)$ if the opening costs are sufficiently small.Comment: A preliminary version accepted to CiE 201

Addressing challenges in uncertainty quantification: the case of geohazard assessments

We analyse some of the challenges in quantifying uncertainty when using geohazard models. Despite the availability of recently developed, sophisticated ways to parameterise models, a major remaining challenge is constraining the many model parameters involved. Additionally, there are challenges related to the credibility of predictions required in the assessments, the uncertainty of input quantities, and the conditional nature of the quantification, making it dependent on the choices and assumptions analysts make. Addressing these challenges calls for more insightful approaches yet to be developed. However, as discussed in this paper, clarifications and reinterpretations of some fundamental concepts and practical simplifications may be required first. The research thus aims to strengthen the foundation and practice of geohazard risk assessments.</p

Risk science offers an integrated approach to resilience

Why do we hear calls to separate and independently manage aspects of risk and resilience that are inherently related? These arguments are inconsistent with more holistic and integrated responses to wicked challenges—such as climate change—that are necessary if we are to find balances and synergies. The justification of such views is based on misconceptions of risk science that are no longer accurate. Rather than being irrelevant, the risk concept and related literature provide a wealth of resilience analysis resources that are potentially being overlooked. In this Perspective, we discuss how the modern view of risk can provide an integrated framework for the key aspects of resilience

On the Epistemology of the Precautionary Principle: Reply to Steglich-Petersen

In a recent paper in this journal, we proposed two novel puzzles associated with the precautionary principle. Both are puzzles that materialise, we argue, once we investigate the principle through an epistemological lens, and each constitutes a philosophical hurdle for any proponent of a plausible version of the precautionary principle. Steglich-Petersen claims, also in this journal, that he has resolved our puzzles. In this short note, we explain why we remain skeptica

Emerging IT risks: insights from German banking

How do German banks manage the emerging risks stemming from IT innovations such as cyber risk? With a focus on process, roles and responsibilities, field data from ten banks participating in the 2014 ECB stress test were collected by interviewing IT managers, risk managers and external experts. Current procedures for handling emerging risks in German banks were identified from the interviews and analysed, guided by the extant literature. A clear gap was found between enterprise risk management (ERM) as a general approach to risks threatening firms’ objectives and ERM’s neglect of emerging risks, such as those associated with IT innovations. The findings suggest that ERM should be extended towards the collection and sharing of knowledge to allow for an initial understanding and description of emerging risks, as opposed to the traditional ERM approach involving estimates of impact and probability. For example, as cyber risks emerge from an IT innovation, the focus may need to switch towards reducing uncertainty through knowledge acquisition. Since individual managers seldom possess all relevant knowledge of an IT innovation, various stakeholders may need to be involved to exploit their expertise

Modelling the effect of charge noise on the exchange interaction between spins

We describe how the effect of charge noise on a pair of spins coupled via the exchange interaction can be calculated by modelling charge fluctuations as a random telegraph noise process using probability density functions. We develop analytic expressions for the time dependent superoperator of a pair of spins as a function of fluctuation amplitude and rate. We show that the theory can be extended to include multiple fluctuators, in particular, spectral distributions of fluctuators. These superoperators can be included in time dependent analyses of the state of spin systems designed for spintronics or quantum information processing to determine the decohering effects of exchange fluctuations.Comment: 7 pages, 2 figure

Risk response strategies for collaborative university-industry R&D funded programs

Universities are centers of knowledge in our societies and their role when it comes to innovation has become more important over the years. Companies have several reasons to engage in research collaborations with universities, namely to gain access to innovative technologies. University-Industry R&D collaborations are expected to play an important role in regional economies, and to fulfill the industry’s demand for innovative products, technologies and processes. However, the knowledge on what are the potential risks resulting from these collaborations and the risk response strategies to reduce the negative risk impacts and to enhance positive risk impacts is still limited. Thus, this paper aims to fill the gap in literature when it comes to risk identification and risk responses’ planning, by identifying, based on a case study analysis, 19 potential risks and 53 potential risk response strategies.INCT-EN - Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção(SFRH/BPD/111033/2015

Review and Evaluation of the J100â 10 Risk and Resilience Management Standard for Water and Wastewater Systems

Risk analysis standards are often employed to protect critical infrastructures, which are vital to a nation’s security, economy, and safety of its citizens. We present an analysis framework for evaluating such standards and apply it to the J100â 10 risk analysis standard for water and wastewater systems. In doing so, we identify gaps between practices recommended in the standard and the state of the art. While individual processes found within infrastructure risk analysis standards have been evaluated in the past, we present a foundational review and focus specifically on water systems. By highlighting both the conceptual shortcomings and practical limitations, we aim to prioritize the shortcomings needed to be addressed. Key findings from this study include (1) risk definitions fail to address notions of uncertainty, (2) the sole use of â worst reasonable caseâ assumptions can lead to mischaracterizations of risk, (3) analysis of risk and resilience at the threatâ asset resolution ignores dependencies within the system, and (4) stakeholder values need to be assessed when balancing the tradeoffs between risk reduction and resilience enhancement.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154262/1/risa13421_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154262/2/risa13421.pd