Uncertainty Circle Research Articles

Diagnosing patient flow issues in the emergency department: an Australasian hospital case study

PurposeThis study investigates how a hospital can increase the flow of patients through its emergency department by using benchmarking and process improvement techniques borrowed from the manufacturing sector.Design/methodology/approachAn in-depth case study of an Australasian public hospital utilises rigorous, multi-method data collection procedures with systems thinking to benchmark an emergency department (ED) value stream and identify the performance inhibitors.FindingsHigh levels of value stream uncertainty result from inefficient processes and weak controls. Reduced patient flow arises from senior management’s commitment to simplistic government targets, clinical staff that lack basic operations management skills, and fragmented information systems. High junior/senior staff ratios aggravate the lack of inter-functional integration and poor use of time and material resources, increasing the risk of a critical patient incident.Research limitations/implicationsThis research is limited to a single case; hence, further research should assess value stream maturity and associated performance enablers and inhibitors in other emergency departments experiencing patient flow delays.Practical implicationsThis study illustrates how hospital managers can use systems thinking and a context-free performance benchmarking measure to identify needed interventions and transferable best practices for achieving seamless patient flow.Originality/valueThis study is the first to operationalise the theoretical concept of the seamless healthcare system to acute care as defined by Parnaby and Towill (2008). It is also the first to use the uncertainty circle model in an Australasian public healthcare setting to objectively benchmark an emergency department's value stream maturity.

Multifactor uncertainty analysis of prefabricated building supply chain: qualitative comparative analysis

PurposeThis paper constructs the uncertainty analysis model of prefabricated building supply chain risk. The model is designed to study the formation path of prefabricated building supply chain risk and is expected to be used by industry stakeholders for supply chain risk management.Design/methodology/approachBased on the uncertainty circle model, construct a configuration analysis framework for supply chain risks in prefabricated buildings. The fuzzy set qualitative comparative analysis (fsQCA) is used to study the configuration influence of five uncertain factors, including environment, plan-control, demand-supply, manufacturing and assembly-transportation, on the risk of the prefabricated building supply chain.FindingsThere are three paths to promote the high-risk generation of the prefabricated building supply chain: assembly-transportation-oriented, plan-control-oriented and manufacturing-oriented. There is a specific equivalent substitution relationship among the five causal conditions. Under specific conditions, different combinations of conditions have the same effect on promoting supply chain high-risk generation through equivalent substitution.Originality/valueThe multiple concurrent causal relationships of risk conditions in the assembly construction supply chain are studied under the grouping perspective, which helps to expand the research perspective of assembly construction supply chain risk and provides theoretical guidance for supply chain risk management of construction enterprises.

Sources of Uncertainties in Offsite Logistics of Modular Construction for High-Rise Building Projects

A critical concern in the supply chain of modular construction is offsite logistics that involve complicated module manufacturing, storage, and transportation processes. However, numerous uncertainties exist in a supply chain that could detrimentally affect the performance of offsite logistics and thereby the success of modular construction projects. A systematic exploration of sources of uncertainties (SoUs) in offsite logistics is needed, as they have not yet been sufficiently investigated. This study aimed to identify and categorize SoUs affecting the offsite logistics of high-rise modular building projects in high-density cities. A multicase study method was adopted involving three modular high-rise projects. Data were collected through documentation, site visits, and interviews, drawing on the uncertainty circle model. A total of 30 key SoUs were identified in five areas: the offsite logistics process, the demand side, the supply side, planning and control systems, and the environment. A framework for SoUs was derived, which showed the multifaceted, interconnected, and context-specific features of SoUs and illustrated their probabilities and impacts. Most SoUs arise from offsite logistics processes and planning and control systems. The demand-side SoUs were found to have higher probabilities and impacts. The supply-side SoUs were less probable but could have significant impacts on offsite logistics. Suggestions are made that would allow practitioners to break uncertainty circles and policymakers to promote the development of a robust modular construction supply chain.

A Note on Observer-Based Frequency Control for a Class of Systems Described by Uncertain Models

This paper focuses on the robust control problem for a class of linear uncertain systems by using frequency techniques. The controller/observer dynamics are analyzed using Lyapunov techniques, in terms of the state and state estimation error, for an uncertainty constrained over a specified range. A Popov-type criterion, a “circle criterion,” defined as the Popov frequency condition and the uncertainty circle, is formulated. It is proved that the closed-loop system is robustly stable if the Popov condition holds at all frequencies. The proposed method is validated against a robust controller for a balancing robot (BR).

A comparative study of manufacturing and service sector supply chain integration via the uncertainty circle model

Purpose – The purpose of this paper is to investigate the differences and similarities between the manufacturing and services sectors in order to develop a methodology that can provide the opportunity for the transfer of best practice between the two sectors. This paper aims to describe an audit methodology capable of yielding objective comparisons of supply chain integration performance that can assist practitioners and academics to transfer learned solutions. Design/methodology/approach – A robust, site-based, multi-method supply chain diagnostic for detecting manufacturing supply chain system uncertainty was amended for the service sector in order to yield objective comparisons of the (normalised) supply chain integration performances of 119 organisations. Findings – The research confirms the value of using a lens enabled by the uncertainty circle model (UCM) for generating meaningful comparative supply chain performances. The research found that services do not always exhibit unique attributes which effectively bar manufacturing-based supply chain best practice from being adopted within the service sector. Originality/value – Combining the UCM and Quick Scan Audit Methodology approach has the potential to assist the spread of proven good practice across both sectors. The framework provides realistic and repeatable performance vectors, capable of aligning estimates of value stream health status even when comparing supply chains with differing objectives, configurations, and performance goals.

Priority Choice Experimental Two-Qubit Tomography: Measuring One by One All Elements of Density Matrices.

In standard optical tomographic methods, the off-diagonal elements of a density matrix ρ are measured indirectly. Thus, the reconstruction of ρ, even if it is based on linear inversion, typically magnifies small errors in the experimental data. Recently, an optimal tomography solution measuring all the elements of ρ one-by-one without error magnification has been theoretically proposed. We implemented this method for two-qubit polarization states. For comparison, we also experimentally implemented other well-known tomographic protocols, either based solely on local measurements (of, e.g., the Pauli operators and James-Kwiat-Munro-White projectors) or with mutually unbiased bases requiring both local and global measurements. We reconstructed seventeen separable, partially and maximally entangled two-qubit polarization states. Our experiments show that our method has the highest stability against errors in comparison to other quantum tomographies. In particular, we demonstrate that each optimally-reconstructed state is embedded in an uncertainty circle of the smallest radius, both in terms of trace distance and disturbance. We explain how to experimentally estimate uncertainty radii for all the implemented tomographies and show that, for each reconstructed state, the relevant uncertainty circles intersect indicating the approximate location of the corresponding physical density matrix.

Causes, effects and mitigation of unreliable healthcare supplies

This study investigates the means by which hospitals can improve the reliability of their medical supply value streams. Field research involving pharmacy supplies in eight Australasian public sector hospitals utilised a rigorous, multi-method data collection procedure based around the uncertainty circle model. Value stream maturity, performance inhibitors and pathways to effective improvement are explored. The high levels of value stream uncertainty detected are commonly the result of process immaturity and poor inter-functional integration. Chief among the common root causes is failure by the executive to acknowledge the strategic value of medical supplies management, which ultimately leads to higher materials cost and increased risk of a medical mishap. The study demonstrates how managers can use systems thinking and a context-free performance benchmark to identify effective interventions and potentially transferable best practices.

Systems engineering effective supply chain innovations

When seeking to adopt innovative supply chain (SC) best practices from apparently better-performing organisations during re-engineering, it is important to acknowledge that context also impacts performance. Hence, the purpose of this study is to evaluate the SC uncertainty circle model for its potential to yield direct performance comparisons even when the benchmarked organisations are located in different business sectors and economic settings. Using a rigorous well-established audit methodology, longitudinal field research with an engineer-to-order SC company demonstrates how highly effective, potentially transferable best practices can be reliably identified when systems thinking is allied to a context-free uncertainty metric, and how reducing product delivery process uncertainty can itself increase innovation capability.

Improving supply chain performance through auditing: a change management perspective

PurposeQuick scan audit methodology (QSAM) has been adapted to include some change management practices. This paper seeks to relate how the company's dissemination feedback presentation sessions and implementation team‐work added value to the established QSAM by: offering a new method of demonstrating a “listening ear” to employees, providing enhanced verification of the QS results, increasing “buy in” and offering the possibility of a deeper knowledge transfer and increased audit accuracy.Design/methodology/approachThis action research project is oriented around diagnosis and improvement of Company A's production‐planning process using an adapted QSAM procedure, and a qualitative investigation into the effect of increasing employee participation in QSAM with a view to increasing its potential as a change management tool. The primary research was largely conducted through semi‐structured interviews designed according to role. An important change management dimension of the primary research was to clearly explain the purpose of the audit at the beginning of each interview. A total of 16 interviews were conducted. The data collected were analysed using standard techniques including: process mapping, Ishikawa cause and effect diagrams, why‐why‐why and Pareto analysis. The accuracy of the company's existing forecasting was measured using mean absolute percentage error (MAPE). The uncertainty circle diagram was used to provide a higher level of analysis, categorising the causes of uncertainty into: supply side, process side, demand side and control side. Once the findings had been presented to the business champion and senior managers, the main findings and suggested solutions were presented throughout the company in a series of six presentations to 40 people over a period of ten days.FindingsA human‐centred QS was successfully applied to Company A with limited resources. With the application of mathematical forecasting models, the forecasting error (MAPE) was reduced from an average of 22 to 18 per cent. Completion of production schedules was increased from 96 to 98 per cent, while packaging efficiency increased from 94 to 96 per cent. Most importantly, the company have established a “road‐map” to achieve a better and more flexible supply chain. The QSAM is a robust auditing tool, but it does not take account of potential resistance to change. Company A have adapted the QSAM to include some basic change management practices, effectively extending its feedback stages through wider dissemination, in order to build consensus and to improve the response to change.Research limitations/implicationsOn the basis of a single case study conducted in a UK food‐manufacturing company, “change management” appears to be compatible with supply chain audit, where this is conducted as a means of driving improvement. The effectiveness of the project is judged via “hard” rather than “soft” measures of supply chain performance. Further external verification would be necessary to generalise from this research, and future research directions are indicated in the paper.Practical implicationsSupply chain improvement projects involving supply chain audit can be enhanced through the integration of change management practices.Originality/valueThe originality of the research stems from the integration of change management practices into the established QSAM.

Reducing uncertainty in European supply chains

In this paper, we show that reducing supply chain uncertainty increases responsiveness and thereby benefits bottom line performance as assessed via total cycle time reduction. We term this effect as the uncertainty reduction principle. To enable uncertainty reduction we use the uncertainty circle to focus on the sources to be eliminated. We also show that these sources of uncertainty can react and magnify in a flywheel effect caused by poor supply chain management. A supply chain audit methodology is described for identifying and codifying uncertainty. The proposition advanced herein is that smooth material flow leads to and statistically correlates with uncertainty reduction. Examples are given of good real‐world supply chain practices thus identified and subsequently improved. Transferability of the uncertainty reduction principle is assured by establishing readily assimilated “best practice” guidelines via the study of “exemplar” operating characteristics.

Integrating the automotive supply chain: where are we now?

Real world supply chains differ not only in their current standard of performance, but also in the most effective actions required to move each towards world class supply. A generic approach for the identification of the appropriate re‐engineering programmes based on the uncertainty circle principle is presented. A total of 20 European automotive supply chains have been analysed via a “quick scan” audit procedure. The output is a clear portrayal of the present “health status” of those supply chains. Some 10 per cent of these are performing at the present day level of “best practice”, with a further 20 per cent within sight of this goal. Specific re‐engineering requirements are identified for the remaining 70 per cent dependent on present maturity levels.

Speeding up the progress curve towards effective supply chain management

Introduces a supply chain “health check” procedure successfully applied in the European automotive sector and presents the results for the analysis of 20 trans‐European value streams covering a wide range of first and second tier suppliers. The health check procedure is activated via a quick scan methodology (QSM) requiring execution by a multi‐disciplinary team working on‐site. The degree of integration within the value chain is estimated by the QS team, using the uncertainty circle concept which apportions observed uncertainties in the product delivery process (PDP) according to source. In our experience the four major contributors are: the demand side; supply side; value added process side; and systems controls. The results clearly demonstrate a well‐trodden and hence proven route for value stream performance improvement. They also identify value chain exemplars and many areas of best practice, but most importantly they provide a list of actions focused on improving the performance of individual value streams. Properly applied, re‐engineering programmes based on these trigger points will speed up the progress curve towards effective supply chain management.

Coping with Uncertainty: Reducing “Bullwhip” Behaviour in Global Supply Chains

All supply chains suffer the effects of uncertainty. One of the most documented (and painful) symptoms is upstream order magnification known as the “Bullwhip Effect”. We believe that companies which cope best with uncertainty via an effective supply chain strategy are most likely to produce internationally competitive bottom-line performance. Although uncertainty takes many forms four key areas within a supply chain structure can represent these. These key segments are the supply side, manufacturing process, process controls and demand side. They may be combined to form the uncertainty circle. It is manifest that the uncertainty present within each of the quadrants must be reduced to maximise competitive advantage and hence market share. The paper therefore proposes a set of actions, which will reduce supply chain uncertainty caused by demand amplification (or the “bullwhip effect”) irrespective of source. The methodology is shown to apply to a wide range of realworld supply chains.

Detection of a Strong Stellar Flare from EUVE J1438−432

We present extreme-ultraviolet (EUV) observations of a strong flare from EUVE J1438-432, a source serendipitously detected with the Extreme Ultraviolet Explorer (EUVE) Right Angle Program. The flare was detected in the Lexan/boron (100 A) band and showed a 16-fold increase over quiescent emission with a rise time of ~10 ks and a decay time of ~40 ks. Optical spectroscopy of objects within the EUVE pointing uncertainty circle revealed a pair of late-type stars (WT 486 and WT 487) both showing Balmer series in emission; either star is a good candidate for production of the flare. The peak luminosity of the flare is 5.7 × 1029 ergs s-1 with a total energy of ~5 × 1033 ergs. The flare energetics are about 2 orders of magnitude lower than the large EUV flare detected from AU Mic in 1992, but similar to other EUV-detected flares from late-type stars.

The Interaction Vector Approach to the Design of Linear Multi-Input Multi-Output Control Systems

Interaction vector displays were first presented as a means of indicating frequency dependent interactions in linear multivariable systems by the superposition of interaction vectors onto an inverse Nyquist array. The vectors can also be defined for a Nyquist array and show how each element q ii (jw) of the open loop frequency response is modified to h i (jw) when all loops are closed excepting loop i. It has been shown how the interaction vectors, or approximations to them, are modified by compensation. Uncertainties in the frequency response of the system model are considered by surrounding each frequency evaluation of the uncompensated g ik (jw) by an uncertainty circle in which the true g ik (jw) must be. It is shown how each approximation interaction vector can then be represented by a nominal vector surrounded by an offset circular bound. The designer can thereby assess the effects of uncertainties at all stages of the interactive design of compensation. The approach is illustrated with examples from the literature