Mission-critical Equipment Research Articles

Analysis of and Decision-Making on the Operational Reliability of Cyber-Physical Systems

Matters concerned with analyzing the operational reliability and recovery process of cyber-physical systems (CPS) are addressed. The proposed approach is based on dividing the CPS life cycle into time intervals with linking them to pre-emergency, emergency, restored and predicted states. The CPS serviceability is restored with respect to extremely critical and mission-critical equipment. In carrying out the analysis, graphs representing the states of cybernetic and physical components are introduced. Differential equations linking the probability of returning into a serviceable state with failure rates and restorations of various types are derived. The solution of the appropriate ordinary differential equations yields a clear graphical interpretation in the time domain and shows the changes in the probability with which the system components transfer from one state to another at different CPS life cycle time slices. By using the developed flow chart of making decisions on restoring or replacing the corresponding component, a reasonable choice can be made among possible options of actions aimed at restoring the serviceability of a multicomponent system. An algorithm for implementing the method has been developed and tested on a numerical example.

Performance-based maintenance contract for mission-critical equipment considering spare parts inventory cost-sharing and suppliers' risk attitudes

Performance-based maintenance contract for mission-critical equipment considering spare parts inventory cost-sharing and suppliers' risk attitudes

INSTALLED BASE SAFETY UPGRADE AT POWER GENERATION STATION

The study case power-generation plant comprises four steam generation units, commissioned in the 1990's, it is one of the largest in Italy and one of major in Europe, contributing to base load demand to the country south region. Age and limited availability of replacement parts for original medium voltage air magnetic circuit breaker, now in obsolete life cycle phase, is an operation concern on such mission critical equipment, as well as racking operation procedure on original 50kA rated installation not internal arc classified. The owning Utility strategy drives energy transition towards an increasingly sustainable model and the plant electrical installed base modernization, focusing on efficiency, health and safety as the three key elements. Innovative retrofit solutions have been designed and fully type tested to enable original installed base modernization with latest circuit breaker technology, providing withdrawable motorized execution for safety and easy maintenance. The benefits in terms of safety upgrade and installation are described. Furthermore, operation benefits such as standardization of spare parts, replacement of mechanical to electrical signalling and easiness of racking procedure is discussed.

Contract design for equipment after-sales service with business interruption insurance

After-sales service is strategically important for mission-critical equipment due to the high operational risks involved (e.g., machine breakdowns). To address this challenge, the operators of such equipment often purchase business interruption (BI) insurance to mitigate operational risks. In this paper, we develop a principal-agent model to study an after-sales service contracting problem with an insurance option. Two prevailing contract forms are considered: a resource-based contract (RBC) and a performance-based contract (PBC). We first show that, in the presence of insurance, a PBC outperforms an RBC in terms of system performance due to the skewed incentives inherent in an RBC. More important, our results show that insurance plays contrasting roles in incentivizing a service supplier under the two contracting mechanisms. Under an RBC, insurance improves the service supplier’s effort provision and hence benefits the operator because insurance provides a risk-sharing mechanism that better aligns the incentives of the service supplier and the operator. Under a PBC, although the supplier’s equilibrium effort remains at the first-best level regardless of the insurance coverage level, the use of insurance changes the operator’s optimal contract and the risk allocation between the operator and the supplier. Our findings provide important insights into the interplay of insurance and contract incentives in an after-sales service context.

Adversarial Testing to Increase the Overall Security of Embedded Systems: A Review of the Process

In the evolving world of the Internet of Things, the security of any piece of electronic equipment can easily come into question. Traditional electronics are being replaced with upgraded smart alternatives that are deployed worldwide as embedded systems in connected cars, autonomous aircraft, wireless medical devices, and control systems. The desire to maintain a constant connection to these systems and share data, monitor operation, and diagnose and resolve performance issues has driven designers and developers to adopt new technologies to support the task. Each of these pieces of technology, whether just the next wirelessenabled gadget or mission critical equipment, offers an attack surface that may be taken advantage of and successfully exploited.

Digiplex: Future-Ready Data Centers

This case is based on DigiPlex, the largest data center provider in Scandinavia. The company plans to build another data center just outside of Stockholm, Sweden. The case asks students to evaluate a project plan and use the data to diagram the critical path. The case opens with DigiPlex chairman Byrne Murphy at the negotiation table with the key anchor customer needed in order to get his newest project off the ground. The project has already been delayed 41 weeks, and Murphy learned that its client might want to postpone the handover another several weeks. Murphy had long trusted critical path analysis during moments where key decisions needed to be made around both engineering problems and economic questions in projects. Murphy had to decide how much more risk and expense they would be taking if the target delivery date changed. In order to answer that question, Murphy referred back to the critical path to rethink it. Excerpt UVA-QA-0880 Oct. 3, 2017 DigiPlex: Future-Ready Data Centers With negotiations running almost a year behind, DigiPlex's Chairman Byrne Murphy was back at the table with the key prospect for the anchor customer needed to get his newest project off the ground. DigiPlex was the largest data center provider in Scandinavia and had plans to build another data center just outside of Stockholm, Sweden. The analysis Murphy relied on indicated that both parties had to agree to a move-in date of the first weekend of April 2015, which was coming up faster and faster. In the meeting, Murphy learned that DigiPlex's client, a large financial institution, would only move over the first weekend in April or would like to postpone the handover to January 1, 2016. At this point, Murphy asked his director of development to step outside the room with him. Murphy had long trusted critical path analysis during moments when key decisions needed to be made around both design problems and economic questions. “The barrier to entry in the data center world is credibility,” Murphy said. “It's no longer the fiber, nor power, nor financing, but rather: Do you have credibility and can I trust you with my mission-critical equipment and data in your center?” Meeting project deadlines was the most fundamental way of preserving credibility. Murphy asked his development director what was needed to do to keep the project on track. The client's move-in date was dependent on contract signing, which was already delayed. “Let's see those charts,” he said. “What is the impact if we suffer another delay?” Byrne Murphy and Critical Path Analysis . . .

Vision Based Altitude Control for a Trajectory Following Quadrotor Using Position Feedback

A quadrotor, or quadrotor helicopter, is an aircraft that becomes airborne due to the lift force provided by four rotors usually mounted in cross configuration, hence its name. They are of particular interest due to their small size, great maneuverability and hovering capability. However quadrotors have a limited payload capacity because they require four motors for operation, which consumes more power than conventional Unmanned Aerial Vehicles. This reduces the number of sensors and mission critical equipment they are able to carry. Due to this limitation researchers have turned to vision-based techniques for navigation of UAVs. Vision-based navigation provides a large number of useful features that extend quadrotors capabilities. They include the basic control functions of keeping the quadrotor roll and pitch angles stable (attitude control), controlling the vehicle trajectories when flying in free spaces (course stabilization), and keeping the altitude at proper height over ground. A color camera tracks the image features under the quadrotor and above ground. These blobs are located on a known geometric shape.

Management Insights

Management Insights

Contracting for Infrequent Restoration and Recovery of Mission-Critical Systems

Firms that rely on functioning mission-critical equipment for their businesses cannot afford significant operational downtime due to system disruptions. To minimize the impact of disruptions, a proper incentive mechanism has to be in place so that the suppliers provide prompt restoration and recovery services to the customer. A widely adopted incentive mechanism is performance-based contracting (PBC), in which suppliers receive compensation based on realized system uptime. A key obstacle is that disruptions occur infrequently, making it very expensive for a supplier to commit the necessary resources for recovery because they will be idle most of the time. In this paper, we show that designing a successful PBC creates nontrivial challenges that are unique to this environment. Namely, because of the infrequent and random nature of disruptions, a seemingly innocuous choice of performance measures used in contracts may create unexpected incentives, resulting in counterintuitive optimal behavior. We compare the efficiencies of two widely used contracts, one based on sample-average downtime and the other based on cumulative downtime, and identify the supplier's ability to influence the frequency of disruptions as an important factor in determining which contract performs better. We also show that implementing PBC may create high agency cost when equipment is very reliable. This counterintuitive situation arises because the realized downtimes from which the customer might intuit about the supplier's capacity investment are highly uncertain when there are not many samples of downtimes, i.e., when disruptions occur rarely.

Electrical Power Failure in the Operating Room

Electrical Power Failure in the Operating Room

An energy operator approach to joint application of amplitude and frequency-demodulations for bearing fault detection

Bearings are among the most frequently used components. Bearing failure could lead to complete stall of a mechanical system, unpredicted productivity loss for production facilities or catastrophic consequence for mission-critical equipment. As such, bearing fault detection and diagnosis is an imperative part of most of preventive maintenance procedures. This paper presents a parameter independent yet simple to implement fault detection technique. The Teager energy operator is tailored to extract both the amplitude and frequency modulations of the vibration signals measured from mechanical systems. The incorporation of the frequency modulation information into the proposed bearing fault detection method has eliminated the need for interference removal steps. As the amplitude demodulation (AD) is also inherent in the energy operator, the fault frequency can be detected from the spectrum of the energy-transformed signal. The effectiveness of the proposed method has been validated using both simulated and experimental data.

Information Technology Principles for Management, Reporting, and Research

Information technology holds the promise to enhance the ability of individuals and organizations to manage emergency departments, improve data sharing and reporting, and facilitate research. The Society for Academic Emergency Medicine (SAEM) Consensus Committee has identified nine principles to outline a path of optimal features and designs for current and future information technology systems. The principles roughly summarized include the following: utilize open database standards with clear data dictionaries, provide administrative access to necessary data, appoint and recognize individuals with emergency department informatics expertise, allow automated alert and proper identification for enrollment of cases into research, provide visual and statistical tools and training to analyze data, embed automated configurable alarm functionality for clinical and nonclinical systems, allow multiexport standard and format configurable reporting, strategically acquire mission-critical equipment that is networked and capable of automated feedback regarding functional status and location, and dedicate resources toward informatics research and development. The SAEM Consensus Committee concludes that the diligent application of these principles will enhance emergency department management, reporting, and research and ultimately improve the quality of delivered health care.

Control of robot arm with virtual environment via the internet

Many enterprises experience difficulty in training people to work with expensive equipment, which is needed for carrying out profitable work tasks (e.g., production line robots). Similar problems are found when work is of a complex and safety-critical nature (e.g., nuclear environments, explosive placement, surgery). A common problem faced by educational institutions concerns the limited availability of expensive robotics equipment, with which students in the didactic program can work, in order to acquire valuable hands on experience. This paper describes a method of education and training involving off-line usage of virtual reality environments for task planning. When tasks are developed to the satisfaction of the trainee, they are exported to remote physical hardware, via the Internet, for real-world execution. Development of the system and the training experiments is discussed, along with some of the issues raised for telerobotics and solutions to the problem of detecting collisions in the virtual world. The approach has been shown to be viable, and increases the education and training possibilities for key workers while maintaining a low cost of ownership. The downtime of mission critical equipment is minimized while the gaining of valuable experience is maximized.

Telerobotics experiments via Internet

Many enterprises experience difficulty in training people to work with expensive equipment, which is needed for carrying out profitable work tasks (e.g., production line robots). Similar problems are found when work is of a complex and safety-critical nature (e.g., nuclear environments, explosive placement, surgery). This paper describes a method of education and training involving offline usage of virtual environments for task planning. When tasks are developed to the satisfaction of the trainee, they are exported to remote physical hardware, via the Internet, for real-world execution. Development of the system and the training experiments is discussed, along with some of the issues raised for telerobotics and solutions to the problem of detecting collisions in the virtual world. The approach has been shown to be viable and increases the education and training possibilities for key workers while maintaining a low cost of ownership. The downtime of mission-critical equipment is minimized while the gaining of valuable experience is maximized.

A Blueprint for Solid State Automatic Bus Transfer Switches

Solid State Automatic Bus Transfer Switches (SSABT) also known as Static Transfer Switches (STS) or Electronic Bus Transfer Switches (EBT) are poised to replace conventional Electro-mechanical Automatic Bus Transfer Switches (ABT) in many applications in the near future. SSABTs offer faster transfer times, superior shock resistance, greater reliability and improved control when compared to conventional ABTs. The faster transfer times of SSABTs makes them ideally suited for mission critical equipment associated with the combat weapons system. As with all mission critical equipment, an application specific design should be selected to insure the effectiveness, reliability and serviceability in a shipboard environment.

Prognostics: What does it mean in condition-based maintenance?

The machinery condition monitoring community continues its search for the ‘‘Holy Grail’’ of prognostics. The problem is that there is no common agreement on two questions: ‘‘What does the term prognostics mean in this context’’? and ‘‘What must be done to achieve it’’? This paper differentiates ‘‘predictive maintenance’’ (in its generally accepted form) from ‘‘condition-based maintenance’’ (which requires prognostics). A justification for development and implementation of the more advanced and cost-effective condition-based maintenance is presented. A working definition of prognostics for the condition-based maintenance community is proposed. Further, a methodology for setting acceptable false alarm rates for both diagnostics and prognostics is presented to frame the problem for the research community in terms of the application environment, particularly for mission critical equipment. [See NOISE-CON Proceedings for full paper.]

An expert systems technology approach to maintenance proficiency

Traditional maintenance training curricula use paper technical manuals to teach “tricks of the trade” in corrective and preventive maintenance which requires multiple adjustments, lengthy calibrations and labor-intensive test/checkout procedures. Rotation often delays personnel assignment to a platform which requires these maintenance skills. The non-availability of skilled maintenance personnel poses a tremendous threat to readiness conditions for mission critical equipment. In order to best support the Navy's maintenance requirements and improve maintenance efficiency, the Naval Research Laboratory at Stennis Space Center, Mississippi developed an Expert Maintenance Advisor (EMA). This paper discusses an approach which implements Expert Systems technology methods to develop an expert maintenance reference. It also addresses the impact of performance support systems and interactive electronic technical manuals in maintenance training.

Redundancy techniques for reliable flight-control computers : J. J. Fleck, IEEE Trans. on Commun. and Electron., 82, 535 (1963)

Traditional maintenance training curricula use paper technical manuals to teach “tricks of the trade” in corrective and preventive maintenance which requires multiple adjustments, lengthy calibrations and labor-intensive test/checkout procedures. Rotation often delays personnel assignment to a platform which requires these maintenance skills. The non-availability of skilled maintenance personnel poses a tremendous threat to readiness conditions for mission critical equipment. In order to best support the Navy's maintenance requirements and improve maintenance efficiency, the Naval Research Laboratory at Stennis Space Center, Mississippi developed an Expert Maintenance Advisor (EMA).This paper discusses an approach which implements Expert Systems technology methods to develop an expert maintenance reference. It also addresses the impact of performance support systems and interactive electronic technical manuals in maintenance training.