A guided rule reduction system for prioritization of failures in fuzzy FMEA

Traditional Failure Mode and Effect Analysis (FMEA) utilizes the Risk Priority Number (RPN) ranking system to evaluate the risk level of failures, to rank failures, and to prioritize actions. Although this method is simple, it suffers from several shortcomings. In this paper, use of fuzzy inference techniques for RPN determination in an attempt to overcome the weaknesses associated with the traditional RPN ranking system is investigated. However, the fuzzy RPN model, suffers from the combinatorial rule explosion problem. As a result, a generic rule reduction approach, i.e. the Guided Rule Reduction System (GRRS), is proposed to reduce the number of rules that need to be provided by users during the fuzzy RPN modeling process. The proposed approach is evaluated using real-world case studies pertaining to semiconductor manufacturing. The results are analyzed, and implications of the proposed approach are discussed.

Fuzzy FMEA with a guided rules reduction system for prioritization of failures

Purpose – To propose a generic method to simplify the fuzzy logic-based failure mode and effect analysis (FMEA) methodology by reducing the number of rules that needs to be provided by FMEA users for the fuzzy risk priority number (RPN) modeling process.

Design/methodology/approach – The fuzzy RPN approach typically requires a large number of rules, and it is a tedious task to obtain a full set of rules. The larger the number of rules provided by the users, the better the prediction accuracy of the fuzzy RPN model. As the number of rules required increases, ease of use of the model decreases since the users have to provide a lot of information/rules for the modeling process. A guided rules reduction system (GRRS) is thus proposed to regulate the number of rules required during the fuzzy RPN modeling process. The effectiveness of the proposed GRRS is investigated using three real-world case studies in a semiconductor manufacturing process.

Findings – In this paper, we argued that not all the rules are actually required in the fuzzy RPN model. Eliminating some of the rules does not necessarily lead to a significant change in the model output. However, some of the rules are vitally important and cannot be ignored. The proposed GRRS is able to provide guidelines to the users which rules are required and which can be eliminated. By employing the GRRS, the users do not need to provide all the rules, but only the important ones when constructing the fuzzy RPN model. The results obtained from the case studies demonstrate that the proposed GRRS is able to reduce the number of rules required and, at the same time, to maintain the ability of the Fuzzy RPN model to produce predictions that are in agreement with experts' knowledge in risk evaluation, ranking, and prioritization tasks.

Research limitations/implications – The proposed GRRS is limited to FMEA systems that utilize the fuzzy RPN model.

Practical implications – The proposed GRRS is able to simplify the fuzzy logic-based FMEA methodology and make it possible to be implemented in real environments.

Originality/value – The value of the current paper is on the proposal of a GRRS for rule reduction to enhance the practical use of the fuzzy RPN model in real environments.

Hybrid cloud resource provisioning policy in the presence of resource failures

Resource provisiomng is an important and challenging problem in the large-scale distributed systems such as Cloud computing environments. Resource management issues such as Quality of Service (QoS) further exacerbate the resource provisioning problem. Furthermore, with the increasing functionality and complexity of Cloud computing, resource failures are inevitable. Therefore, the question we address in this paper is how to provision resources to applications in the presence of resource failures in a hybrid Cloud computing environment. To this end, we propose three Cloud resource provisioning policies where we utilize workflow applications to drive the system workload. The proposed strategies take into account the workload model and the failure correlations to redirect requests to appropriate Cloud providers. Using real failure traces and workload models, we evaluated the performance and monetary cost of the proposed policies. The results of our experiments show that we can decrease the deadline violation rate of users' requests to as low as 20% with a limited cost on Amazon public Cloud.

Vibration based damage identification of a scale-model steel frame structure subjected to bolt connection failures

Large-span steel frame structures prove to be an ideal choice for their speed of construction, relatively low cost, strength, durability and structural design flexibility. For this type of structure, the beam-column connections are critical for its structural integrity and overall stability. This is because a steel frame generally fails first at its connectors, due to the change in stress redistribution with adjacent members and material related failures, caused by various factors such as fire, seismic activity or material deterioration. Since particular attention is required at a steel frame’s connection points, this study explores the applicability of a comprehensive structural health monitoring (SHM) method to identify early damage and prolong the lifespan of connection points of steel frames. An impact hammer test was performed on a scale-model steel frame structure, recording its dynamic response to the hammer strike via an accelerometer. The testing procedure included an intact scenario and two damage scenarios by unfastening four bolt connections in an accumulating order. Based entirely on time-domain experimental data for its calibration, an Auto Regressive Average Exogenous (ARMAX) model is used to create a simple and accurate model for vibration simulation. The calibrated ARMAX model is then used to identify various bolt-connection related damage scenarios via R² value. The findings in this study suggest that the proposed time-domain approach is capable of identifying structural damage in a parsimonious manner and can be used as a quick or initial solution.

Was monochloramine responsible for widespread lettuce crop failures at a major recycled water irrigation scheme?

In 2008, vegetable growers observed stunted lettuce plants showing signs of chlorosis and wilting. It was suspected that monochloramine in the recycled water used for irrigation, in combination with extreme environmental conditions (high irrigation water salinity and extreme heat), was responsible for these crop failures. A series of glasshouse studies was conducted to evaluate the impact of monochloramine concentration alone on iceberg lettuce seedlings, as well as in combination with high salinity and hot ambient temperatures. Monochloramine concentrations up to 9 and 15 mg L−1 Cl2 for continuous and initial irrigation only, respectively, did not affect the weight of iceberg lettuce heads (p > 0.05), while the combination of monochloramine (4–5 mg L−1 Cl2) and salinity (3,500 μS cm−1) did not significantly affect harvest measurements (p > 0.05). We therefore conclude that it is unlikely that monochloramine was responsible for the observed crop failures.

Failures in communication through documents and documentation across the perioperative pathway.

AIMS AND OBJECTIVES: To explore how communication failures occur in documents and documentations across the perioperative pathway in nurses' interactions with other nurses, surgeons and anaesthetists. BACKGROUND: Documents and documentation are used to communicate vital patient and procedural information among nurses, and in nurses' interactions with surgeons and anaesthetists, across the perioperative pathway. Previous research indicates that communication failure regularly occurs in the perioperative setting. DESIGN: A qualitative study was undertaken. METHODS: The study was conducted over three hospitals in Melbourne, Australia. One hundred and twenty-five healthcare professionals from the disciplines of surgery, anaesthesia and nursing participated in the study. Data collection commenced in January 2010 and concluded in October 2010. Data were generated through 350 hours of observation, two focus groups and 20 semi-structured interviews. A detailed thematic analysis was undertaken. RESULTS: Communication failure occurred owing to a reliance on documents and documentation to transfer information at patient transition points, poor quality documents and documentation, and problematic access to information. Institutional ruling practices of professional practice, efficiency and productivity, and fiscal constraint dominated the coordination of nurses', surgeons' and anaesthetists' communication through documents and documentation. These governing practices configured communication to be incongruous with reliably meeting safety and quality objectives. CONCLUSIONS: Communication failure occurred because important information was sometimes buried in documents, insufficient, inaccurate, out-of-date or not verbally reinforced. Furthermore, busy nurses were not always able to access information they required in a timely manner. Patient safety was affected, which led to delays in treatment and at times inadequate care. RELEVANCE TO CLINICAL PRACTICE: Organisational support needs to be provided to nurses, surgeons and anaesthetists so they have sufficient time to complete, locate, and read documents and documentation. Infrastructure supporting communication technologies should be implemented to enable the rapid retrieval, entry, and dispersion of information.

Failures in communication through documents and documentation across the perioperative pathway

Aims and objectives: To explore how communication failures occur in documents and documentations across the perioperative pathway in nurses' interactions with other nurses, surgeons and anaesthetists. Background: Documents and documentation are used to communicate vital patient and procedural information among nurses, and in nurses' interactions with surgeons and anaesthetists, across the perioperative pathway. Previous research indicates that communication failure regularly occurs in the perioperative setting. Design: A qualitative study was undertaken. Methods: The study was conducted over three hospitals in Melbourne, Australia. One hundred and twenty-five healthcare professionals from the disciplines of surgery, anaesthesia and nursing participated in the study. Data collection commenced in January 2010 and concluded in October 2010. Data were generated through 350 hours of observation, two focus groups and 20 semi-structured interviews. A detailed thematic analysis was undertaken. Results: Communication failure occurred owing to a reliance on documents and documentation to transfer information at patient transition points, poor quality documents and documentation, and problematic access to information. Institutional ruling practices of professional practice, efficiency and productivity, and fiscal constraint dominated the coordination of nurses', surgeons' and anaesthetists' communication through documents and documentation. These governing practices configured communication to be incongruous with reliably meeting safety and quality objectives. Conclusions: Communication failure occurred because important information was sometimes buried in documents, insufficient, inaccurate, out-of-date or not verbally reinforced. Furthermore, busy nurses were not always able to access information they required in a timely manner. Patient safety was affected, which led to delays in treatment and at times inadequate care. Relevance to clinical practice: Organisational support needs to be provided to nurses, surgeons and anaesthetists so they have sufficient time to complete, locate, and read documents and documentation. Infrastructure supporting communication technologies should be implemented to enable the rapid retrieval, entry, and dispersion of information.

Disproportionate ownership structure and IPO long-run performance of non-SOEs in China

This paper examines the relationship between ownership structures and IPO long-run performance of non-SOEs in China. Although non-SOEs underperform the market in general after IPO but the poor performance is mainly caused by the IPOs with ownership control wedge. Non-SOEs with one share one vote structure outperform those with control-ownership wedge by 30% for three years post-IPO performance in adjusted buy-and-hold returns. Non-SOEs with control-ownership wedge have higher frequency of undertaking value-destroying related party transactions. These findings suggest that non-SOEs need to improve corporate governance such as disproportionate ownership structure to better safeguard the interest of long-run shareholders.

Does political capital create value in the IPO market? Evidence from China

This study examines the value of political capital in the Chinese IPO market. We find a positive relationship between a politically connected executive and the probability of IPO approval of entrepreneurial firms. We further identify that shareholders value those connections and give a market premium to connected firms after the firms go public. We provide evidence that other types of political capital gained through external sources, such as politically connected sponsors and PE investors, also bring benefits to the firms in their IPO approval, and these connections substitute for the effect of the executive's political connections on IPO approval. We argue that in emerging markets where government intervention is still prevalent, political capital does create value and entrepreneurial firms usually build political capital to facilitate their access to the IPO market, although other types of political capital do not bring further benefits into the post-IPO market.

Board structure and survival of new economy IPO firms

Research Question/Issue: This study examines the relevance of currently accepted best practice recommendations regarding board structure on the survival likelihood of new economy initial public offering companies. We argue that industry context determines governance outcomes. Research Findings/Insights: We study 125 Australian new economy firms listed between 1994 and 2002. Each firm is tracked until the end of 2007 for monitoring their survival. We find that board independence is associated with an increase in the likelihood of corporate survival. We also find that the benefits of board independence increase at a decreasing rate. Theoretical/Academic Implications: The standard best practice recommendation of board independence stems from the monitoring role of directors and is based on agency theory. The results from our study suggest that the recommendation regarding board independence does not work well for new economy firms. While the agency theory based model implies a monotonic relation between board independence and performance, our research suggests that the relationship is nonlinear. This variation occurs because of increased monitoring costs faced by outsiders due to higher information asymmetry and complexity of new economy firms. Our empirical results suggest that inside directors play a complementary role to outsiders in mitigating firm failure. Practitioner/Policy Implications: Our research offers insights to policy makers who are interested in setting best practice standards regarding board structure. Our research suggests that firm/industry characteristics play a crucial role in determining the optimal board structure. In firms/industries where outsiders face significantly higher information processing costs, insiders can play a valuable complementary role to outsiders in enhancing the effectiveness of the board. Thus future hard or soft regulations related to board structure should consider industry context.

A new two-stage fuzzy inference system-based approach to prioritize failures in failure mode and effect analysis

This paper presents a new Fuzzy Inference System (FIS)-based Risk Priority Number (RPN) model for the prioritization of failures in Failure Mode and Effect Analysis (FMEA). In FMEA, the monotonicity property of the RPN scores is important. To maintain the monotonicity property of an FIS-based RPN model, a complete and monotonically-ordered fuzzy rule base is necessary. However, it is impractical to gather all (potentially a large number of) fuzzy rules from FMEA users. In this paper, we introduce a new two-stage approach to reduce the number of fuzzy rules that needs to be gathered, and to satisfy the monotonicity property. In stage-1, a Genetic Algorithm (GA) is used to search for a small set of fuzzy rules to be gathered from FMEA users. In stage-2, the remaining fuzzy rules are deduced approximately by a monotonicity-preserving similarity reasoning scheme. The monotonicity property is exploited as additional qualitative information for constructing the FIS-based RPN model. To assess the effectiveness of the proposed approach, a real case study with information collected from a semiconductor manufacturing plant is conducted. The outcomes indicate that the proposed approach is effective in developing an FIS-based RPN model with only a small set of fuzzy rules, which is able to satisfy the monotonicity property for prioritization of failures in FMEA.