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The system encountering dormant failure subject to sequential inspections is modeled and the emphasis is made on determining the availability and long-run average cost rate for the model. The derived results are then utilized to obtain the optimal inspection period minimizing the cost.

Explicitly, a system with a functional and a failed state is taken into account. Inspections are performed to reveal the dormant failures and are assumed to be carried out at time T, T + aT, T + aT+a² T, … where 0 < a = 1 in each cycle. Perfect repairs taking random times are performed if the system is found in a failed state during any inspection.

Some theorems on the point availability, limiting availability and long-run average cost rate are obtained in the study. An illustration is shown to explain the results obtained in the proposed work. The effect of inspection time on the availability and cost rate is also analyzed graphically.

The availability and cost rate for a system with dormant failure under a sequential inspection policy are figured out unlike previous research.

The objective of this paper is to demonstrate basic economic principles underlying the use of inspection systems and to derive a basis for comparing inspection costs with the alternative costs of quality improvement.

For this purpose, the impact of final, rectifying and sequential inspection on unit production costs is assessed using a production process model with uniform defect propensity in the single process steps. Based on this model, an objective function with the objective of minimizing unit production costs including inspection costs is formulated and a genetic algorithm method used to optimize it.

Two distinct patterns of optimal inspection allocation could be detected for changing defect rate, processed volume, fixed inspection costs and variable input costs. These allocation patterns highlight the basic economic relations of an inspection approach and verify the assumption that sequential inspection schemes are cost‐optimal. However, the benefits of quality improvement are found to be superior to any inspection scheme for a majority of cases.

The findings are derived from a theoretical examination. Further limitations stem from the cost‐centred approach which only covers the internal component of an economic assessment of quality. However, the economic perspective advanced in this paper can in future be subjected to empirical testing and be elaborated by subsequent research.

Although built on simplifying assumptions, the process model can provide important insights into basic economic relations and demonstrate that inspection is an inferior way of dealing with quality problems. It can thereby help to promote a better economic understanding of quality.

This paper provides an economic assessment of an important aspect of quality management, which has so far not been advanced.

In certain environments, the system may not fail completely, but undergoes degradation, and the system productivity might decrease. Meanwhile, at the same time, the system may be vulnerable to shocks. A single-unit system prone to degradation and shocks is proposed in this study, and emphasis is placed upon determining its availability and cost rate.

The considered single-unit system is expected to have three states, namely, normal, degraded and failed. As the system enters the degraded state, it is said to be partially failed. The degraded state incurs higher degradation than the normal state and is more prone to shocks. Inspections are used to determine the state and failure type of the system. Inspections are predetermined to be carried out sequentially at time I, I+aI, I+aI+a2I,… where 0 < a ≤ 1, until the detection of degradation/failure. Perfect repairs are conducted instantly on spotting the partial/complete failure. Two cases have been considered of repair taking constant times and random times.

Explicit results on the reliability, availability (both point and limiting availability) and long-run average cost rate (LRACR) of a sequentially inspected single-unit system prone to degradation and shocks under constant and random repair times are given. Numerical example of an oil pipeline system is taken to clarify the acquired results.

A sequentially inspected single-unit system prone to degradation and shock is studied unlike done previously.

In statistical process control, a number of items are selected from all items produced every h time units (which we will refer to as an inspection period); these items are used to make inferences about the state of an unreliable machine or process. This paper considers an unreliable process which can shift from an acceptable in‐control state to an unacceptable out‐of‐control state. Based on a Shewhart‐type c‐chart, this paper extends the framework developed in Klastorin et al. to define the expected number of samples needed to confirm that the process shift has occurred when we use a sequential sample of the last n items produced in an inspection period. Comparing this result to the case where a random sample is used, we show that the probability of detecting the shift using a sequential sample is greater than or equal to the probability of detecting the shift using a random sample. Thus, sequential samples will result in a control chart that requires fewer expected samples to detect a shift and has lower expected total costs.

This paper aims to use a video‐taped fragment of conduct and interaction in a museum to illustrate the analysis of visitors' interactionally produced response to works of art.

The method draws on ethnomethodology and conversation analysis to investigate the social and sequential organisation of people's action and interaction. The fragment discussed as part of this paper sheds light on the social and interactional production of people's response to and experience of exhibits.

The detailed analysis of one video‐fragment illustrates how the analysis progresses from an inspection of the sequential organisation of talk to an examination of the sequential organisation of verbal, visual and bodily conduct. The analysis also makes a small substantive contribution to current debates on people's experience of artwork in museums. In particular, the findings suggest that the experience of works of art is not a subjective and cognitive response to the objects, but arises in and through socially organised, embodied practices at the exhibit‐face.

The paper discusses an innovative way to analyze video‐data, and makes a contribution to the growing body of research in arts marketing and museum marketing on the exhibition floor.

Sampling plans for inspection by attributes contain rules for passing from normal to tightened inspection. Usually only the operating characteristic curve (O.C.) will apply but in tightened inspection, lots are unlikely to remain in tightened inspection and inspection will be terminated. This means that the normal and tightened O.C. curves are boundary curves and the true O.C. curve is a composite of both. This article presents a method for calculating the composite O.C. curve and proposes three criteria to compare switching rules.

The authors consider systems that generate damage to environment as they get older and degrade. The purpose of this paper is to develop an optimal condition-based maintenance strategy for such systems in situations where they have a finite operational time requirement. The authors determine simultaneously the optimal number of inspections and the threshold level of environmental damage which minimize the total expected cost over the considered finite time horizon.

The environmental degradation level is monitored through periodic inspections. The authors model the environmental degradation process due to the equipment’s degradation by the Wiener process. A mathematical model and a numerical procedure are developed. Numerical calculations are performed and the influence of the variation of key parameters on the optimal solution is investigated.

Numerical tests indicate that as the cost of the penalty related to the generation of an excess damage to environment increases, inspections should become more frequent and the threshold level should be lowered in order to favor preventive actions reducing the probability to pay the penalty.

Given the complexity of the cost function to be minimized, it is difficult to derive analytically the optimal solution. A numerical procedure is designed to obtain the optimal condition-based maintenance policy. Also, the developed model is based on the assumption that the degradation follows a process with stationary independent increments. This may not be appropriate for all types of degradation processes.

The proposed optimal maintenance policy may be relevant and very useful in the perspective of green operations. In fact, this paper offers to decision-makers a comprehensive approach to implement a green maintenance policy and to rapidly understand the net effect of the maintenance policy with respect to environmental regulation requirements.

The main contribution consists in the modeling and optimization of the condition-based maintenance policy over a finite time horizon. Indeed, existing condition-based maintenance models over an infinite time horizon are not applicable for systems with a finite operational time requirement.

Recent fire disasters in Hong Kong and other cities in China show that fire safety should receive more attention. In Hong Kong, a large number of pre‐1980 high‐rise buildings were designed according to old prescriptive building and fire codes. The fire protection measures of these buildings may not be the same as the standard in effect today, even if all fire safety items have been well maintained. Assessment of the fire safety level of these old buildings – on the basis of current prescriptive requirements – may return a conclusion that many buildings’ fire safety systems are “sub‐standard”, and the fire safety level is unacceptably low. However, whether such a conclusion is warranted, thereby triggering immediate improvement action, is debatable, because the rigid prescriptive requirements in the fire codes do not provide a holistic picture of the fire safety level in these buildings. This paper discusses the issues of site inspections for a systematic approach to perform the fire safety ranking for multi‐storey buildings.

A continuous‐time multi‐state Markovian deteriorating system subject to aging and fatal shocks under continuous inspection is investigated in this paper. An action is chosen from {do‐nothing, repair, replace} upon each state x transited from the resulting state after the last action and so it is state‐dependent. Henceforth, a state‐dependent maintenance policy R_i,j(T,N,α) in which two states i < j are used as thresholds to control the repair and replacement in the way that the repair (resp. replacement) is taken whenever the state x satisfies i ≤ x ≤ j – 1 (resp. j ≤ x ≤ L). The performance of this state‐dependent maintenance policy is measured in terms of the expected long run cost rate. An iterative algorithm is provided to optimize the proposed maintenance policy. A numerical example is given to illustrate the method.

A collaborative design environment is needed for multidisciplinary design optimization (MDO) process, based on all the modules those for different design/analysis disciplines, and a systematic coupling should be made to carry out aerodynamic shape optimization (ASO), which is an important part of MDO.

Computerized environment for aircraft synthesis and integrated optimization methods (CEASIOM)-ASO is developed based on loosely coupling all the existing modules of CEASIOM by MATLAB scripts. The optimization problem is broken down into small sub-problems, which is called “sequential design approach”, allowing the engineer in the loop.

CEASIOM-ASO shows excellent design abilities on the test case of designing a blended wing body flying in transonic speed, with around 45 per cent drag reduction and all the constraints fulfilled.

Authors built a complete and systematic technique for aerodynamic wing shape optimization based on the existing computational design framework CEASIOM, from geometry parametrization, meshing to optimization.

CEASIOM-ASO provides an optimization technique with loosely coupled modules in CEASIOM design framework, allowing engineer in the loop to follow the “sequential approach” of the design, which is less “myopic” than sticking to gradient-based optimization for the whole process. Meanwhile, it is easily to be parallelized.