Experience-based Judgments Research Articles

Safety and comfort assessment of a train passing over an earthquake-damaged bridge based on a probability model

After an earthquake, a track-bridge system may suffer damage and residual deformation, posing a threat for trains passing over a bridge. However, since railway transportation is an important channel for disaster relief, the timely passage of trains is of great significance for the transportation of materials and personnel. In the past, subjective and experience-based judgments were made on whether a train can pass over an earthquake-damaged bridge, and no relevant numerical calculations were carried out. Therefore, a strategy for the evaluation of train performance when passing over existing bridges after earthquakes was proposed. The strategy considers the randomness of track irregularity, and evaluates the running safety performance (RSP) and running comfort performance (RCP) of trains passing over existing bridges from the perspective of probability. The probability law of a lateral residual bridge deformation influence on the RSP and RCP after an earthquake was revealed. Finally, the maximum train passing speed which ensures the RSP was recommended.

A study on the performance assessment of anti-terrorism physical protection systems in chemical plants

The threat originating from deliberate attacks against process and chemical sites where relevant quantities of hazardous substances are stored or processed is a credible one, as confirmed by the attacks carried out in France in the summer of 2015. Although such chemical sites implement multiple layers of protection to address safety-related accidents, they often get behind with providing adequate attention and resources to the protection of assets against external adversaries or, in other words, terrorist threats. The lack of a consolidated practice in the risk-informed implementation of security countermeasures goes hand in hand with the existence of very few rigorous approaches to the effectiveness assessment of security systems, and in particular of physical protection systems (PPSs). The present study addresses the issue of quantitatively assessing the effectiveness of physical security systems adopted to protect process and storage facilities, recognized as high-consequence loss physical assets. To this purpose, the security functions of PPSs were analyzed to guide the selection of performance parameters. Experts from the industry were involved to identify variables and influencing factors relevant to the successful accomplishment of security functions. Experience-based judgments on performance, to be expressed in terms of probabilistic estimates, were also obtained. An insight into the belief that experts hold on the probability of PPSs effectively preventing the success of an external attack and in the identification of critical elements was obtained. The application of the results to the quantitative assessment of the contribution of security controls in reducing vulnerability was also addressed.

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating (SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system, the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means (FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.

Sequentially simulated outcomes: Kind experience versus nontransparent description.

Recently, researchers have investigated differences in decision making based on description and experience. We address the issue of when experience-based judgments of probability are more accurate than are those based on description. If description is well understood ("transparent") and experience is misleading ("wicked"), it is preferable to experience. However, if description is not transparent, will valid ("kind") experience lead to more accurate judgments? We report 2 experiments. The first involved 7 well-known probabilistic inference tasks. Participants differed in statistical sophistication and answered with and without experience obtained through sequentially simulated outcomes. The second experiment involved interpreting the outcomes of a regression analysis when making inferences for investment decisions. In both experiments, even the statistically naïve achieved accurate probabilistic inferences after experiencing sequentially simulated outcomes, and many preferred this presentation format. We conclude by discussing theoretical and practical implications.

Discussion of “Probability and Risk of Slope Failure” by F. Silva, T. W. Lambe, and W. A. Marr

The discussers had the opportunity to use the subject paper in an important consulting problem involving bearing stability. We thought the paper provided very useful experience-based judgments, and applying it to our consulting problem allowed us to possibly expand the potential use of the paper. Peck 1969, p. 174–176 explained the initial problem with the potential instability of NASA’s tracked transporter TR. The TR carried the Apollo, and later the shuttle rockets, several kilometers from the vertical assembly building VAB to the A and B launch pads along the A and B crawlerways CW at the Cape Kennedy Space Center in Florida. The CWs have now experienced roughly 100 loaded TR transverses to periodically stress and improve the CW foundation conditions as well as experiencing approximately 45 years of aging since construction. However, NASA’s proposed new Constellation series of rockets include the Ares V, and it will increase the TR bearing load on the CWs by approximately 35%. Our problem: to estimate the probability of success, or reliability, of the TR carrying an Ares V rocket and traversing the weakest foundation area under the existing CW without any distress that could delay a launch. We found the subject paper useful to make the first phase of this estimate, as described below. We first made a comprehensive field investigation of the most critical part of the CWs as identified by Peck 1969. Then we used the information produced to model the problem and predict pore pressure generation and settlement during a first traverse with the new loading. Settlement seemed acceptable but bearing stability remained an issue. A 2D limit equilibrium, slope stability analysis for bearing stability gave a FS= 1.25. Then a draft copy of the subject paper became available and gave us a methodology for estimating reliability. To do this we assumed that the paper applied to all slopes, including our very flat slope of only 3°. We later assumed it also applied to a 2D finite-element analysis. We also estimated from the Table 1 found in the paper under Discussion guide that our overall level of engineering for the problem fell between categories I and II. Using these at FS= 1.25 with the experience curves in Fig. 1 found in the paper under Discussion, the theoretical curves in Fig. 2 found in the paper under Discussion, and the $10 7 consequences curves in Fig. 5 found in the paper under Discussion, we estimated that the annual probability of a bearing stability failure fell between 10 �2 to 10 �4 . Because previous experience Peck 1969 showed the first traverse as the most critical, we concluded that the probability of success equaled at least 99% for the first traverse of the TR carrying the Ares V over only the critical part of the CW identified by Peck. The above methodology provided a quantitative estimate of the probability of success at 99%, based on the authors’ experience. This seemed consistent with our own subjective thinking. It appears that engineers might also use the paper to evaluate the reliability of bearing stability on a surface with a near-zero slope angle. We look forward to the authors’ comments.

Correcting experience-based judgments: the perseverance of subjective experience in the face of the correction of judgment

Many of our cognitive and metacognitive judgments are based on sheer subjective experience. Subjective experience, however, may be contaminated by irrelevant factors, resulting in biased judgments. Under certain conditions people exert a metacognitive correction process to remedy such biased judgments. In this study we examine the proposition that even after a judgment has been corrected to avoid the biasing effects on subjective experience, subjective experience itself remains biased. We asked participants to judge the difficulty of anagrams for others. When they were aware of having been exposed to the solutions of some of the anagrams, they corrected their difficulty judgments for these anagrams. Despite this correction, their speeded choices in a subsequent task disclosed their biased subjective experience that these anagrams were easier to solve. Implications for the study of metacognition and for the educational domain are discussed.

Goal Programming for Marketing Decisions: A Case Study

T HE reality of business management requires that individual actions taken with respect to particular business functions be evaluated for their probable overall impact. Marketing actions are no exception. Before resources are committed to a marketing proposal, management needs to determine as efficiently as possible the probable results for each of the identified, admissible alternative courses of action. Contemplated marketing actions must be pretempered by careful analysis as to their likely effects on other functional activities and their potential contributions at every level in the organization's hierarchy of goals. Fortunately, the decision sciences have evolved to a point where such careful, efficient analysis is now practicable through the application of mathematical and, specifically, goal programming. Of course, such techniques do not obviate the need for a decision. The contribution of goal programming derives from its structure, which permits logical, sequential progression through analyses that heretofore were largely dependent on intuitive appeals and experience-based judgments. Unlike other quantitative techniques such as linear programming, goal programming provides a way for managers to determine the extent to which several conflicting goals may be realized simultaneously. The following problem and its solution via a goal programming model demonstrate one way that analyses of multifaceted problems or opportunities can be improved with reasonable investments of time and effort.