Potential Failure Points Research Articles

PETRI NETS MODELING FOR SDN TOPOLOGIES

The article examines some new algorithms and focuses mainly on suggesting new working topologies for software-defined controllers in order to ensure SDN security and to prevent the occurrence of a potential central point of failure (SPOF) by overcoming the centralization problem. This is a positive feature of the SDN structure, but could also be a threat, caused by the use of several controllers in different working topologies. This article focuses on exactly one of the suggested topologies, which features and models based on the Petri Nets system. The usual topology of a single controller is compared to verify the advantages and privileges of the proposed serial topology over the existing one. The paper tries to obtain a formula from the modeling of the serial topology and its advantages over the usual topology and that formula will be used to measure the level of security or the defense capacity of the network defined by the software against cyber attacks; in particular, denial of service attacks / distributed denial of service attacks / DDoS.

Use of failure modes and effects analysis to mitigate potential risks prior to implementation of an intravenous compounding technology.

DisclaimerIn an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.PurposeThe purpose of this study was to identify potential failure points in a new chemotherapy preparation technology and to implement changes that prevent or minimize the consequences of those failures before they occur using the failure modes and effects analysis (FMEA) approach.MethodsAn FMEA was conducted by a team of medication safety pharmacists, oncology pharmacists and technicians, leadership from informatics, investigational drug, and medication safety services, and representatives from the technology vendor. Failure modes were scored using both Risk Priority Number (RPN) and Risk Hazard Index (RHI) scores.ResultsThe chemotherapy preparation workflow was defined in a 41-step process with 16 failure modes. The RPN and RHI scores were identical for each failure mode because all failure modes were considered detectable. Five failure modes, all attributable to user error, were deemed to pose the highest risk. Mitigation strategies and system changes were identified for 2 failure modes, with subsequent system modifications resulting in reduced risk.ConclusionThe FMEA was a useful tool for risk mitigation and workflow optimization prior to implementation of an intravenous compounding technology. The process of conducting this study served as a collaborative and proactive approach to reducing the potential for medication errors upon adoption of new technology into the chemotherapy preparation process.

Temperature and time effects of post-weld heat treatments on tensile properties and microstructure of Zircaloy-4

Opportunities exist to expand the application of Zircaloy-4 (Zry-4) into lower-temperature (<100°C) applications. Welded areas within these structures are potential failure points and post-weld heat treatments (PWHTs) are not yet standardized for application in this temperature range. Zry-4 tungsten inert gas (TIG) welds were given PWHTs from 450-900°C with hold times from 0.5-48 hours to investigate changes to tensile properties and microstructure. Treatment of 800°C for 1 hour was found to produce the most ductile material, measured by total elongation of the tensile bar (16.5%). Both PWHT time and temperature were observed to increase total elongation, except in extreme (>800°C or >18hours) cases, but the effect of temperature was stronger. The second order cumulative annealing parameter shows a trend with tensile properties. Average grain sizes in the fusion zone and heat affected zone did not change under any of the PWHTs until the development of an undesirable blocky-alpha phase, which was only observed to form in the heat affected zones for hold times greater than 18hr at 800°C.

Cryo-Electron Microscopy and Mass Analysis of Oligolysine-Coated DNA Nanostructures.

Cationic coatings can enhance the stability of synthetic DNA objects in low ionic strength environments such as physiological fluids. Here, we used single-particle cryo-electron microscopy (cryo-EM), pseudoatomic model fitting, and single-molecule mass photometry to study oligolysine and polyethylene glycol (PEG)-oligolysine-coated multilayer DNA origami objects. The coatings preserve coarse structural features well on a resolution of multiple nanometers but can also induce deformations such as twisting and bending. Higher-density coatings also led to internal structural deformations in the DNA origami test objects, in which a designed honeycomb-type helical lattice was deformed into a more square-lattice-like pattern. Under physiological ionic strength, where the uncoated objects disassembled, the coated objects remained intact but they shrunk in the helical direction and expanded in the direction perpendicular to the helical axis. Helical details like major/minor grooves and crossover locations were not discernible in cryo-EM maps that we determined of DNA origami coated with oligolysine and PEG-oligolysine, whereas these features were visible in cryo-EM maps determined from the uncoated reference objects. Blunt-ended double-helical interfaces remained accessible underneath the coating and may be used for the formation of multimeric DNA origami assemblies that rely on stacking interactions between blunt-ended helices. The ionic strength requirements for forming multimers from coated DNA origami differed from those needed for uncoated objects. Using single-molecule mass photometry, we found that the mass of coated DNA origami objects prior to and after incubation in low ionic strength physiological conditions remained unchanged. This finding indicated that the coating effectively prevented strand dissociation but also that the coating itself remained stable in place. Our results validate oligolysine coatings as a powerful stabilization method for DNA origami but also reveal several potential points of failure that experimenters should watch to avoid working with false premises.

BigFintechs and Their Impacts on Macroeconomic Policies

This paper follows directly from the paper “BigFintechs and their Impact on Sustainable Development”, which examines the positive and negative impacts of BigFintech (BFT) activities across the full spectrum of the Sustainable Development Goals (SDGs), particularly with regard to Least Developed Countries (LDCs). This paper serves as an extension of the analysis, specifically on the findings with regard to SDG 16 (peace, justice and strong institutions) to focus on the macroeconomic impact of BFT actors and activities on LDCs. To accomplish the extended analysis, we first address the limitations in bridging BFT activity, SDG indicators and LDC macroeconomic policy impacts. We draw upon the outline of the complex and opaque supply chains, expanding service offerings across multiple business verticals, and the complex ecosystem models that amplify BFT impacts for LDCs. We discuss the key barriers in advancing the analysis including the limitations of the frameworks, tools, indicators and data, to measure the macroeconomic impacts, particularly within the LDC context. Our findings demonstrate that the current narrative ‘digital economy’ sees digital growth, maturity, and market penetration in LDCs largely as positive developments. However, it fails to address the potential for adverse impacts on LDCs specifically owing to BFTs’ complex models and business activities. We then outline the regulatory challenges related to BFT across multiple factors including the cross-border nature of BFT ecosystems and activities, the narrow scope of those digital services, the limitations of foreign exchange rules and taxation classification. In this paper, we set out the positive impacts of BFTs on reducing inequalities, access to capital, increased employment and entrepreneurship and GDP growth, as well as more complex negative implications including potential tax avoidance, crowding out of local businesses and SMEs, evolving ecosystems of interdependence with single points of failure, the potential for draining liquidity from local financial systems and for currency substitution. We discuss the regulatory capacity to address these macroeconomic impacts as well as the new potential points of failure being introduced. The paper then addresses the limitations of current governance parameters and structures that are struggling to keep up with the power, size and complex business model evolution of BFTs generally. The paper points to a widening gap in terms of primary or targeted regulatory focus for LDCs, which are not generally within the scope or mandate of regulators and legislators in more developed markets where most BFTs are headquartered. A summary of the potential macroeconomic impacts and regulatory challenges is followed by a series of conclusions indicating that rather than expanding their current value proposition of financial inclusion, employment and economic growth, BFTs can actually bypass or exploit segments of communities in LDCs with negative environmental, social and economic impacts. We further extrapolate the potential negative impact of BFTs on financial or currency stability that could bypass engagement with national taxation and regulation, through shadow banking particularly given the fragmented regulatory space. Finally, we offer key recommendations to consider with regard to alternative incentives and tools for BFTs to address and report on activities and impacts in LDCs, as well as innovative regulatory approaches for more effective measurement, analysis and remediation of risks and impacts of BFTs on LDCs.

Approximation of elastic-plastic local strains in surface-hardened notched components

Elastic-plastic strains at points relevant for structural failures are usually approximated using formulas based on the stresses determined by elasticity theory. For this purpose, the Neuber approximation is a common method to estimate the local elastic-plastic strains in the notch root, although this is currently only approved for homogeneous components. For surfacehardened notched components, these approximation formulas need to be modified to cover two potential failure points: The notch root as well as the interface between the stronger surface layer and the weaker core material. In the following, a multi-step algorithm is shown that allows the estimation of elastic-plastic local strains at these two points, based on a single elasticitytheoretical solution. A comparison of the approximated values with those from finite element analyses (FEA) reveals that this results in only minor inaccuracies, while the usability is remarkable.

Integrating FMEA and the Kano Model to Improve the Service Quality of Logistics Centers

This study uses the logistics center of a large organic retail store in Taiwan to analyze service blueprint and workflow, identifying the potential points of failure and thus serving as a basis for quality improvement. The failure mode and effect analysis (FMEA) model is an effective problem prevention methodology that can easily interface with many engineering and reliability methods. The utilized method integrates the failure mode and effect analysis (FMEA) and the Kano model to explore the possible occurrence of failures in the internal workflow and services of the studied logistics center. A two-stage survey was conducted. In the first stage, an investigation was conducted by 20 logistics experts on the FMEA’s key service failures. In the second stage, a questionnaire was filled out by 220 store staff to summarize the logistics service quality factors found in the Kano model. The results show that the degree of attention and satisfaction in the priority improvement items when there were service failures vary among the opinions of different internal employees and customers. The participants jointly believed that the items that need improvement are “Damaged incoming goods” and “A shortfall in the quantities of delivered goods”.

Monitoring Network Changes during the 2018 Kīlauea Volcano Eruption

Abstract In the summer of 2018, Kīlauea Volcano underwent one of its most significant eruptions in the past few hundred years. The volcano’s summit and East Rift Zone magma system partially drained, resulting in a series of occasionally explosive partial caldera collapses, and widespread lava flows in the lower East Rift Zone. The Hawaiian Volcano Observatory (HVO) operates a robust permanent monitoring network of about 250 stations, recording a variety of real-time data streams: seismic (short-period, broadband, strong-motion), infrasound, Global Navigation Satellite Systems (GNSS), tilt, camera, laser rangefinder, and gas geochemistry. During the eruption, HVO staff quickly established 35 new temporary monitoring stations, to better constrain evolving volcanic hazards. The partial collapses of the caldera threatened to disrupt important telemetry links in the HVO monitoring network, and a major effort was undertaken in the midst of the eruption crisis to reroute radio telemetry and maintain continuity of data flow. In the process, a new data center was established in Hilo, to mitigate a long-standing potential single point of failure at the HVO facility. Over the course of the eruption from May through August, lava, ashfall, wildfire, and cliff collapse destroyed or disabled 36 stations. Thousands of earthquakes damaged the main HVO facility at Uēkahuna Bluff, causing staff to evacuate the building and relocate observatory operations in the midst of the eruption response, adding more complexity to the response effort. Throughout these events, the HVO team maintained the monitoring network, provided timely information to the public and emergency managers, and collected valuable scientific data to better understand Kīlauea Volcano.

A Fuzzy Design Decision Model for New Healthcare Service Conceptualization

This paper purpose a structural design decision model by using service blueprint, failure mode effect analysis (FMEA), Fuzzy method, and the theory of inventive problem solving (TRIZ). In “service process analysis” stage, the service blueprint approach is used to analyze the potential service failure points in the service process. Then, FMEA is employed to diagnose the possible causes and effects of the service failure model in “service failure diagnosis” stage. The service failure models are prioritized according to the calculated integrated Risk Priority Number (RPN) and fuzzy number. In “innovative principle generation” stage, the innovative principles are generated by utilizing the TRIZ matrix. Finally, in “innovative solution conceptualization” stage, the TRIZ inventive principles are used to inspire the new solution for new service design. An empirical survey of home-care service agencies in Beijing is conducted to demonstrate the applicability of the proposed 2S2I model to improve home-care services, medical-equipment designs, and service delivery. The advantages, implications, and contributions of 2S2I model are also concluded.

Application of composite materials in sports optics

CFRP (Carbon Fiber Reinforced Polymers) are often used when designing parts that need to be stiff, light and thermally stable. These benefits are a big motivation to use CFRP in many applications, one of them could be sports optics. However, optical devices require precise dimensions with tight tolerances for the opti-cal assembly to work correctly. In order to determine if CFRP could be a suitable material of choice for sports optics a simplified body of binoculars was designed. The main purpose of this prototype was to prove the possibility of using CFRP in binoculars. The tubular body was manufactured by prepreg lay-up into a 3D printed mold, followed by curing in an autoclave. After the prototype was manufactured 3D measurements of the tube using 3D scanner GOM ATOS were made. As expected, shrinkage of the mold and the epoxy resin in the matrix of CFRP caused minor deformations. However, if the shape of the cured part remains unchanged during conditions similar to the general use of binoculars, then the initial deformations happening during manufacturing could be accoun-ted for when designing the part. Other than the carbon part itself, the bond between metal and composite components is another potential point of failure in terms of desired precision. Because of that measurements and tests of concentricity of ad-hesive joints are being currently performed. The results of these tests and others that will follow will indicate if composite materials could be used as a structural material for sports optics.

Additive Manufacturing (AM) of Metallic Alloys

The introduction of metal additive manufacturing (AM) processes in industrial sectors, such as the aerospace, automotive, defense, jewelry, medical and tool-making fields, has led to a significant reduction in waste material and in the lead times of the components, innovative designs with higher strength, lower weight and fewer potential failure points from joining features [...]

Hazard analysis for identifying common cause failures of digital safety systems using a redundancy-guided systems-theoretic approach

Replacing the existing aging analog instrumentation and control (I&C) systems with modern safety control and protection, digital technology offers one of the foremost means of performance improvements and cost reductions for the existing nuclear power plants (NPPs). However, the qualification of digital I&C systems remains a challenge, especially considering the issue of software common-cause failures (CCFs), which are difficult to address. With the application and upgrades of advanced digital I&C systems, software CCFs have become a potential threat to plant safety because most redundant designs use similar digital platforms or software in the operating and application systems. With complex designs of multilayer redundancy to meet the single-failure criterion, digital I&C safety systems (e.g., engineered safety-features actuation system [ESFAS]) are of a particular concern in the U.S. Nuclear Regulatory Commission (NRC) licensing procedures. This paper applies a modularized approach to conduct redundancy-guided systems-theoretic hazard analysis for an advanced digital ESFAS with multilevel redundancy designs. Systematic methods and risk-informed tools are incorporated to address both hardware and software CCFs, which provide guidance to eliminate the causal factors of potential single points of failure in the design of digital safety systems in advanced plant designs.

Assessing and Reducing Risk to Healthcare Workers in Outbreaks.

The 2014-2016 West African Ebola epidemic was devastating in many respects, not least of which was the impact on healthcare systems and their health workforce. Healthcare workers-including physicians, clinical officers, nurses, midwives, and community health workers-serve on the front lines of efforts to detect, control, and stop the spread of disease. Risk mitigation strategies, including infection prevention and control (IPC) practices, are meant to keep healthcare workers safe from occupational exposure to disease and to protect patients from healthcare-associated infections. Despite ongoing IPC efforts, steady rates of both healthcare-associated and healthcare worker infections signal that these mitigation measures have been inadequate at all levels and present a potential critical point of failure in efforts to limit and control the spread of outbreaks. The fact that healthcare workers continue to be infected or are a source of infection during public health emergencies reveals a weakness in global preparedness efforts. Identification of key points of failure-both within the health system and during emergencies-is the first step to mitigating risk of exposure. A 2-pronged solution is proposed to address long-term gaps in the health system that impact infection control and emergency response: prioritization of IPC for epidemic preparedness at a global level and development and use of rapid risk assessments to prioritize risk mitigation strategies for IPC. Without global support, evidence, and systems in place to support the lives of healthcare workers, the lives of their patients and the health system in general are also at risk.

The Good, the Bad, and the Ethical Implications of Bridging Blockchain and Multi-Agent Systems

The agent based approach is a well established methodology to model distributed intelligent systems. Multi-Agent Systems (MAS) are increasingly employed in applications dealing with safety and information critical tasks (e.g., in eHealth, financial, and energy domains). Therefore, transparency and the trustworthiness of the agents and their behaviors must be enforced. For example, employing reputation based mechanisms can promote the development of trust. Nevertheless, besides recent early stage studies, the existing methods and systems are still unable to guarantee the desired accountability and transparency adequately. In line with the recent trends, we advocate that combining blockchain technology (BCT) and MAS can achieve the distribution of the trust, removing the need for trusted third parties (TTP), potential single points of failure. This paper elaborates on the notions of trust, BCT, MAS, and their integration. Furthermore, to attain a trusted environment, this manuscript details the design and implementation of a system reconciling MAS (based on the Java Agent DEvelopment Framework (JADE)) and BTC (based on Hyperledger Fabric). In particular, the agents’ interactions, computation, tracking the reputation, and possible policies for disagreement-management are implemented via smart contracts and stored on an immutable distributed ledger. The results obtained by the presented system and similar solutions are also discussed. Finally, ethical implications (i.e., opportunities and challenges) are elaborated before concluding the paper.

Optimising paediatric afferent component early warning systems: a hermeneutic systematic literature review and model development

ObjectiveTo identify the core components of successful early warning systems for detecting and initiating action in response to clinical deterioration in paediatric inpatients.MethodsA hermeneutic systematic literature review informed by translational...

Vulnerability of South Korea's Undersea Cable Communications Infrastructure:A Geopolitical Perspective

It is impossible to overstate the importance of undersea cable communications infrastructure (UCCI) to the national and economic security of South Korea. As an isolated, peninsular state surrounded by rivals and aggressors, South Korea depends heavily on these cables, which carry everything from financial transactions to critical military communications. Yet security analysts have devoted little attention to the dangers that come with this dependence. The following paper presents a unique analysis of South Korea s security by focusing on five potential points of failure, thereby highlighting a critical area of national vulnerability. Conclusions suggest policymakers and national security specialists should take additional measures to protect the South Korean state and society from potential damage to this vital infrastructure.

Quality of maternal obstetric and neonatal care in low-income countries: development of a composite index

BackgroundIn low-income countries, studies demonstrate greater access and utilization of maternal and neonatal health services, yet mortality rates remain high with poor quality increasingly scrutinized as a potential point of failure in achieving expected goals. Comprehensive measures reflecting the multi-dimensional nature of quality of care could prove useful to quality improvement. However, existing tools often lack a systematic approach reflecting all aspects of quality considered relevant to maternal and newborn care. We aim to address this gap by illustrating the development of a composite index using a step-wise approach to evaluate the quality of maternal obstetric and neonatal healthcare in low-income countries.MethodsThe following steps were employed in creating a composite index: 1) developing a theoretical framework; 2) metric selection; 3) imputation of missing data; 4) initial data analysis 5) normalization 6) weighting and aggregating; 7) uncertainty and sensitivity analysis of resulting composite score; 8) and deconstruction of the index into its components. Based on this approach, we developed a base composite index and tested alternatives by altering the decisions taken at different stages of the construction process to account for missing values, normalization, and aggregation. The resulting single composite scores representing overall maternal obstetric and neonatal healthcare quality were used to create facility rankings and further disaggregated into sub-composites of quality of care.ResultsThe resulting composite scores varied considerably in absolute values and ranges based on method choice. However, the respective coefficients produced by the Spearman rank correlations comparing facility rankings by method choice showed a high degree of correlation. Differences in method of aggregation had the greatest amount of variation in facility rankings compared to the base case. Z-score standardization most closely aligned with the base case, but limited comparability at disaggregated levels.ConclusionsThis paper illustrates development of a composite index reflecting the multi-dimensional nature of maternal obstetric and neonatal healthcare. We employ a step-wise process applicable to a wide range of obstetric quality of care assessment programs in low-income countries which is adaptable to setting and context. In exploring alternative approaches, certain decisions influencing the interpretation of a given index are highlighted.

Is immunohistochemistry-based screening for Lynch syndrome in endometrial cancer effective? The consent's the thing

PurposeTo investigate the plausible failure rate of the immunohistochemistry (IHC)-based screening protocol to identify Lynch syndrome (LS) index cases among endometrial cancer (EC) patients. MethodsWe developed a simulation model of the IHC protocol in this context. The model was populated from systematic and focused reviews, augmented with local data and expert opinion. The virtual cohort represents the number of women expected to be diagnosed with EC in the U.S. in 2018. The outcomes include protocol failure rates and LS cases missed in a variety of hypothetical scenarios. ResultsThe best estimate of failure rate of the IHC protocol is 58%; minimum and maximum estimates are 33% and 80%, respectively. These failure rates are driven primarily by the high rates of failure to obtain consent from patients for sequencing (25% to 80%). The multiple imperfect tests and potential failure points in this protocol, collectively, make up 7% to 20% of the total failure rate. When consent for sequencing was fixed in the model at 25%, 50%, and 80%; the expected ranges for index case identification failure are 78%–82%, 57%–64%, and 29%–42%, respectively. ConclusionThe primary driver of failure to identify index cases remains consent for sequencing. Consent rates have shown little improvement since LS screening programs were instituted in the U.S., leaving us to conclude these high failure rates are resistant to substantial improvement. These missed opportunities will be magnified because cascade screening for carrier status among family members will not be pursued.

First Operation of a Resistive Shell Liquid Argon Time Projection Chamber: A New Approach to Electric-Field Shaping

We present a new technology for the shaping of the electric field in Time Projection Chambers (TPCs) using a carbon-loaded polyimide foil. This technology allows for the minimisation of passive material near the active volume of the TPC and, thus, is capable to reduce background events originating from radioactive decays or scattering on the material itself. Furthermore, the high and continuous electric resistivity of the foil limits the power dissipation per unit area and minimizes the risks of damages in the case of an electric field breakdown. Replacing the conventional field cage with a resistive plastic film structure called “shell” decreases the number of components within the TPC and, therefore, reduces the potential points of failure when operating the detector. A prototype liquid argon (LAr) TPC with such a resistive shell and with a cathode made of the same material was successfully tested for long-term operation with electric field values up to 1.6 k V cm − 1 . The experiment shows that it is feasible to successfully produce and shape the electric field in liquefied noble-gas detectors with this new technology.

Understanding system-focused barriers to the identification and reporting of medication errors and adverse drug events in emergency medical services

Emergency medical services (EMS) represent an important and increasingly used entry point into the healthcare system. These services are often provided in the backdrop of challenging environments, with few diagnostic resources available, and for patients of varying acuity. As a result, the potential for medication errors (MEs) and adverse drug events (ADEs) is significant. However, the identification and reporting of these occurrences is poorly understood. A healthcare failure mode and effects analysis was conducted at the Hamad Medical Corporation Ambulance Service, Qatar, to identify and mitigate potential system-focused barriers to the identification and reporting of ADEs and MEs in the EMS setting. Between May 2018 and July 2018, a process map and potential failure points were developed and identified. Probabilities, severity, and hazard scores were calculated for each failure point, and action items were developed to address these. In total, 110 potential failure points were identified among 22 sub-processes, divided between six major processes. In terms of severity, most were classified as either ‘moderate’ [n = 90 (80%)] or ‘major’ [n = 14 (13%)]. In terms of probability, failure points classified as ‘frequent’ [n = 39 (35%)] and ‘occasional’ [n = 38 (35%)] made up the majority. Through consensus, 76 failure points (69%) were deemed necessary for action. Five strategic-level, system-focused action items were identified to mitigate against the failure points meeting the criteria for action. The unique circumstances that occur within the EMS setting dictate that bespoke solutions be developed to allow for ease of implementation and ongoing success of use. Strategies that also take advantage of mobile technology are crucial for a service that has mobility as one of its core functions.