scholarly journals An ad hoc decision support method over additive vs. conventional manufacturing

2020 ◽  
Vol 318 ◽  
pp. 01028
Author(s):  
Stamatios Polydoras ◽  
Clio Vossou ◽  
Dimitrios Koulocheris
Keyword(s):  
Ad Hoc ◽  
Time Pressure ◽  
Mechanical Design ◽  
Final Decision ◽  
Critical Design ◽  
Design Flexibility ◽  
Short Run ◽  
Successful Design ◽  
Recent Trends ◽  
Design Factors

The mechanical design process considers numerous factors. Requirements related to performance and quality, limitations by legislation, standards, methods utilized or technological boundaries, urgency, cost, data preparation and preservation, design flexibility and organizational aspects. Successful design consists of proper decisions on form, geometry, materials, manufacturing methods, quality, reliability and more. Nowadays, a critical decision during design and realization of technological objects is whether they should be made conventionally or with Additive Manufacturing (AM)/3D Printing methods. Such a decision occurs under time-pressure or via a broader strategy for technological switch, is complex, multi-parametric and bears uncertainty and risk. A simple, effective and substantiated method to assist decisions for switching from conventional to AM could prove very useful. This paper refers to recent trends and activity in international AM-related standards, then presents and discusses preliminary work of the authors for an ad hoc decision method to be used upon specific “go/ no-go” decisions for AM. The method is largely based on the Pareto principle, to limit critical design factors contributing to this decision. All steps of the method towards a final decision are described. The method is demonstrated with a hypothetical, yet realistic example of a short run coolant vessel manufacture.

Nonlinear Dynamics and Chaos: Application to Financial Markets in Pakistan

1994 ◽  
Vol 33 (4II) ◽  
pp. 1417-1429 ◽  
Author(s):  
Nasir M. Khiui
Keyword(s):  
Financial Markets ◽  
Chaotic Dynamics ◽  
Ad Hoc ◽  
Linear Models ◽  
Brain Research ◽  
Economic Data ◽  
Differential Equation Models ◽  
Short Run ◽  
The Business Cycle ◽  
Random Shocks

Recently there has been an increased interest in the theory of chaos by macroeconomists and fmancial economists. Originating in the natural sciences, applications of the theory have spread through various fields including brain research, optics, metereology, and economics. The attractiveness of chaotic dynamics is its ability to generate large movements which appear to be random, with greater frequency than linear models. Two of the most striking features of any macro-economic data are its random-like appearance and its seemingly cyclical character. Cycles in economic data have often been noticed, from short-run business cycles, to 50 years Kodratiev waves. There have been many attempts to explain them, e.g. Lucas (1975), who argues that random shocks combined with various lags can give rise to phenomena which have the appearance of cycles, and Samuelson (1939) who uses the familiar multiplier accelerator model. The advantage of using non-linear difference (or differential) equation models to explain the business cycle is that it does not have to rely on ad hoc unexplained exogenous random shocks.

scholarly journals Cooperation Promotion from the Perspective of Behavioral Economics: An Incentive Mechanism Based on Loss Aversion in Vehicular Ad-Hoc Networks

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 225 ◽  
Author(s):  
Jiaqi Liu ◽  
Shiyue Huang ◽  
Hucheng Xu ◽  
Deng Li ◽  
Nan Zhong ◽  
...  
Keyword(s):  
Ad Hoc Networks ◽  
Loss Aversion ◽  
High Speed ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Incentive Mechanism ◽  
Final Decision ◽  
The Incentive Mechanism ◽  
Hoc Networks

As a special mobile ad-hoc network, Vehicular Ad-hoc Networks (VANETs) have the characteristics of high-speed movement, frequent topology changes, multi-hop routing, a lack of energy, storage space limitations, and the possible selfishness of the nodes. These characteristics bring challenges to the design of the incentive mechanism in VANETs. In the current research on the incentive mechanism of VANETs, the mainstream is the reward-based incentive mechanism. Most of these mechanisms are designed based on the expected utility theory of traditional economics and assume that the positive and negative effects produced by an equal amount of gain and loss are equal in absolute value. However, the theory of loss aversion points out that the above effects are not equal. Moreover, this will lead to a deviation between the final decision-making behavior of nodes and the actual optimal situation. Therefore, this paper proposed a Loss-Aversion-based Incentive Mechanism (LAIM) to promote the comprehensive perception and sharing of information in the VANETs. This paper designs the incentive threshold and the threshold factor to motivate vehicle nodes to cooperate. Furthermore, based on the number of messages that the nodes face, the utility function of nodes is redesigned to correct the assumption that a gain and a loss of an equal amount could offset each other in traditional economics. The simulation results show that compared with the traditional incentive mechanism, the LAIM can increase the average utility of nodes by more than 34.35%, which promotes the cooperation of nodes.

On Integration of Additive Manufacturing During the Design and Development of a Rehabilitation Robot: A Case Study

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Kaci E. Madden ◽  
Ashish D. Deshpande
Keyword(s):  
Additive Manufacturing ◽  
Neurological Disorders ◽  
Development Process ◽  
Mechanical Design ◽  
Rehabilitation Robotics ◽  
Critical Design ◽  
Rehabilitation Robots ◽  
Time Optimization ◽  
Hand Exoskeleton

The field of rehabilitation robotics has emerged to address the growing desire to improve therapy modalities after neurological disorders, such as a stroke. For rehabilitation robots to be successful as clinical devices, a number of mechanical design challenges must be addressed, including ergonomic interactions, weight and size minimization, and cost–time optimization. We present additive manufacturing (AM) as a compelling solution to these challenges by demonstrating how the integration of AM into the development process of a hand exoskeleton leads to critical design improvements and substantially reduces prototyping cost and time.

Estimating Errors in Concept Selection

1995 ◽  
Author(s):  
K. N. Otto ◽  
Kristin L. Wood
Keyword(s):  
Error Propagation ◽  
Final Decision ◽  
Selection Methods ◽  
Concept Selection ◽  
Confidence Measure ◽  
Critical Design ◽  
Fundamental Causes ◽  
Design Alternatives ◽  
Degree Of Confidence ◽  
Numerical Concept

Abstract Numerical concept selection methods are used throughout industry to determine which among several design alternatives should be further developed. The results, however, are rarely believed at face value. Uncertainties (or errors) in subjective choices, modeling assumptions, and measurement are fundamental causes of this disbelief. This paper describes a methodology developed to predict overall error ranges, in addition to estimating a confidence measure in the numerical evaluation results. Each numerical assignment is given an associated error tolerance, and then treated as a probability error to create a simple means to propagate the uncertainties. A degree of confidence is also derived, similar to a statistical t-test, to indicate an induced confidence level in the final decision. Two preliminary concept selections are shown, to illustrate the methodology. Results from these concept selections indicate that (1) uncertainties can be suitably captured and quantified; (2) critical design questions are addressed during the process of numerical concept selection with error propagation; and (3) designers can make more informed and confident decisions through error estimation.

scholarly journals On the ballast–sleeper interaction in the longitudinal and lateral directions

2016 ◽  
Vol 232 (2) ◽  
pp. 620-631 ◽  
Author(s):  
Antonio De Iorio ◽  
Marzio Grasso ◽  
Francesco Penta ◽  
Giovanni Pio Pucillo ◽  
Stefano Rossi ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Mechanical Design ◽  
Field Tests ◽  
Longitudinal Direction ◽  
Detailed Knowledge ◽  
Research Activity ◽  
Lateral Direction ◽  
Technical Literature ◽  
Testing Conditions ◽  
Ballast Resistance

In service, railway tracks must withstand the transverse and longitudinal forces that are caused by running vehicles and thermal loads. The mechanical design that adopts any of the track models available in the technical literature requires that the strength of the track is fully characterised. In this paper, the results of an experimental research activity on the sleeper–ballast resistance along the lateral and the longitudinal directions are reported and discussed. In particular, the work is aimed at identifying the strength contributions offered by the base, the ballast between the sleepers, and the ballast shoulder to the global resistance of the track in the horizontal plane. These quantities were experimentally determined by means of an ad hoc system designed by the authors. Field tests were carried out on a series of track sections that were built to simulate scenarios in which the ballast was removed from the crib and/or the shoulder. The results of this study indicate that the strength percent contributions from the crib, the sleeper base, and the shoulder are, respectively, equal to about 50%, 25%, and 25% in the lateral direction, and 60%, 30%, and 10% in the longitudinal direction. Moreover, the comparison of the acquired data with literature results reveals that a detailed knowledge about the testing conditions and the activated ballast failure mechanisms is needed in order to correctly use the test data for the design purpose.

scholarly journals Human Performance Consequences of Automated Decision Aids: The Impact of Time Pressure

2020 ◽  
pp. 001872082096501
Author(s):  
Tobias Rieger ◽  
Dietrich Manzey
Keyword(s):  
Human Performance ◽  
Time Pressure ◽  
Negative Impact ◽  
Positive Impact ◽  
Decision Aids ◽  
Final Decision ◽  
X Rays ◽  
Performance Consequences ◽  
Human Operators ◽  
The Impact

Objective The study addresses the impact of time pressure on human interactions with automated decision support systems (DSSs) and related performance consequences. Background When humans interact with DSSs, this often results in worse performance than could be expected from the automation alone. Previous research has suggested that time pressure might make a difference by leading humans to rely more on a DSS. Method In two laboratory experiments, participants performed a luggage screening task either manually, supported by a highly reliable DSS, or by a low reliable DSS. Time provided for inspecting the X-rays was 4.5 s versus 9 s varied within-subjects as the time pressure manipulation. Participants in the automation conditions were either shown the automation’s advice prior (Experiment 1) or following (Experiment 2) their own inspection, before they made their final decision. Results In Experiment 1, time pressure compromised performance independent of whether the task was performed manually or with automation support. In Experiment 2, the negative impact of time pressure was only found in the manual but not in the two automation conditions. However, neither experiment revealed any positive impact of time pressure on overall performance, and the joint performance of human and automation was mostly worse than the performance of the automation alone. Conclusion Time pressure compromises the quality of decision-making. Providing a DSS can reduce this effect, but only if the automation’s advice follows the assessment of the human. Application The study provides suggestions for the effective implementation of DSSs in addition to supporting concerns that highly reliable DSSs are not used optimally by human operators.

EWU-Krisenmanagement: Warum die Politik auf dem richtigen Weg ist

2012 ◽  
Vol 63 (3) ◽  
Author(s):  
Werner Becker ◽  
Horst Löchel
Keyword(s):  
Crisis Management ◽  
Euro Area ◽  
Ad Hoc ◽  
Banking Union ◽  
Current Crisis ◽  
European Banking Union ◽  
Short Run ◽  
European Banking ◽  
Great Persistence ◽  
The Right

SummaryWith troubles in the European Monetary Union (EMU) showing great persistence, the emergency measures and ad-hoc crisis management of European authorities has been subject to harsh criticism. The current fierce debate among economists and the broad public has given rise to two camps advocating fundamentally different approaches how to exit the sustained crisis. While according to the Integrationists′ view, the only viable way to get rid of pressing debt problems and to restore confidence in the Euro area lies in a common guarantee for national debt obligations, so-called Minimalists advocate a strict return to the cornerstones of the Maastricht Treaty, in particular strict compliance with the debt and deficit limits laid out by the Treaty as well as a credible application of the ‚no-bail-out‘ rule. However, in their pure form, both strategies do not serve for a timely and effective crisis management as they either require a level of supranational integration that - given the still prevalent Westphalian order - cannot be attained in the short run nor is it on the agenda of European policy, or essentially deny the significant flaws within the EMU architecture that failed to prevent current fiscal woes.The current crisis management of European authorities has followed neither of the two extremes but has taken a viable middle-of-the-road approach that resulted in useful and necessary repairs to the institutional architecture of the Euro area, most notably the establishment of the commonly guaranteed stability mechanisms EFSF and ESM as well as the first steps taken towards a European banking union. Hence, in contrast to most observers, we argue that the European authorities, by operating a prudent stepby- step approach, are on the right track towards solving the current crisis. As a result, European Central Bank could move back to its original approach of monetary policy.

Critical design factors for successful e-commerce systems

2002 ◽  
Vol 21 (3) ◽  
pp. 185-199 ◽  
Author(s):  
Jinwoo Kim ◽  
Jungwon Lee
Keyword(s):  
Critical Design ◽  
Design Factors

scholarly journals Countries Embracing Maternal Employment Have Opened Schools Sooner after COVID-19 Lockdowns

2020 ◽  
Author(s):  
Ansgar Hudde ◽  
Natalie Nitsche
Keyword(s):  
Decision Making ◽  
Maternal Employment ◽  
Ad Hoc ◽  
Time Pressure ◽  
Gender Ideology ◽  
Policy Decision ◽  
School Closure ◽  
Policy Makers ◽  
Policy Measures

During and after the first wave of COVID-19 lockdowns, the timing and the intensity of school reopenings have varied across countries. We show that societal gender ideology likely has affected school closure and opening policies. Societies that are more supportive of maternal employment have reopened schools significantly sooner than societies less supportive of maternal employment, relative to other opening measures and net of infection rates. Our study contributes novel evidence on the role of attitudes on policy-decision making, and unveils the presence of a potential gender ideology bias in policy-makers’ ad-hoc decision-making under time pressure. The epidemic threat remains high and questions about the operation of schools continue to be a pressing matter. Considering this bias in decision-making can improve further policy-measures during the remainder of the pandemic, and beyond.

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