Optimal design of sensor networks for vehicle detection, classification, and monitoring

The tracking and identification of vehicles for the purpose of surveillance is a widespread application. Observations from a network of sensors can be used to make decisions regarding the identity of vehicles, as well as their trajectories. Generally, the information provided by a sensor network is limited, so vehicles may be misclassified, go undetected, and/or their trajectories may not be determined uniquely. Often, assumptions are made regarding, for example, traffic composition and possible vehicle trajectories. Because the performance of a sensor network can be sensitive to these assumptions, the conclusions made by the network about the identity and trajectory of vehicles can be highly inaccurate. In this paper, these assumptions are treated as possible models of reality that are subsequently evaluated in a decision framework. Mathematical models for vehicle movement and sensor behavior are developed. Candidate designs for the sensor network are considered, where each design is defined by the number, location, and range of the sensors. Methods from decision theory are used to determine the optimal design for the sensor network.     

I'll Find it Where I Can: Exploring the Role of Resource and Financial Constraints in Search Behaviour among Innovators

The search for new knowledge is often driven by problems that firms face in their innovative activities. Although a considerable effort has been made to explore the search for innovation, little attention has been placed on the concept of problemistic search. Indeed, there are only few studies that examine how the challenges that firms face in their innovation processes shape the nature and direction of their search activities. Using the Finnish Innovation Survey, this study explores the impact of different types of problems on the use of internal and external knowledge sources. The results show that firms under resource constraints tend to use external sources of knowledge in their search activities rather than internal ones. However, those firms who are constrained by finance tend to search both internally and externally. The paper explores the implications of these results for theory and future empirical research.     

Reflecting on the philosophy of technology in China in the form of five questions

In China, philosophical research on technology should focus on dealing with practical problems such as exploring how to construct harmonious relationships between technology and science, technology and society, as well as technology and human development during a period of great economic and social transformation. The construction needs to be based on China's social and cultural contexts. Efforts also need to be made to help engineers, technologists, and the public understand and undertake corresponding social responsibilities in order to facilitate the sustainable development of society.     

Cyclic optimisation for localisation in freeform surface inspection

Over the last decade, several papers have been published on the contribution of the Theory of Constraints (TOC) and Throughput Accounting to product mix decisions. In these papers, the quality of the TOC-based approach to generate good or even optimal solutions is assessed with very different results, particularly when compared with other product mix decision tools. It is the objective of this article to expose the often, not explicitly revealed, premises that are mandatory for generating optimal product mix decisions using a TOC-based approach. By analysing several examples, which are modifications of one and the same basic example, premises on the solution space and the objective function are examined and conclusions made, which are shown in a checklist at the end of the paper. If more than one binding multi-product constraint occurs, optimal product mix decisions can only be derived in special cases. Also, the assumption of integer solutions may lead to non-optimal TOC-based solutions. Furthermore, a correct cost allocation is mandatory, even if sometimes not easily conductible. In particular, taking into account only (all) material costs may lead to wrong decisions. Finally, it is shown that discontinuities in the objective functions deriving, for example, from price discounts, may affect the product mix decision and require special modifications of the TOC-based approach.     

Texting while driving as impulsive choice: A behavioral economic analysis

The goal of the present study was to examine the utility of a behavioral economic analysis to investigate the role of delay discounting in texting while driving. A sample of 147 college students completed a survey to assess how frequently they send and read text messages while driving. Based on this information, students were assigned to one of two groups: 19 students who frequently text while driving and 19 matched-control students who infrequently text while driving but were similar in gender, age, years of education, and years driving. The groups were compared on the extent to which they discounted, or devalued, delayed hypothetical monetary rewards using a delay-discounting task. In this task, students made repeated choices between $1000 available after a delay (ranging from 1 week to 10 years) and an equal or lesser amount of money available immediately. The results show that the students who frequently text while driving discounted delayed rewards at a greater rate than the matched control students. The study supports the conclusions that texting while driving is fundamentally an impulsive choice made by drivers, and that a behavioral economic approach may be a useful research tool for investigating the decision-making processes underlying risky behaviors.     

Different risk thresholds in pedestrian road crossing behaviour: A comparison of French and Japanese approaches

When crossing the road, pedestrians have to make a trade-off between saving time and avoiding any risk of injuries. Here, we studied how culture influences an individual's perception of risks when crossing a street, using survival analysis. This study is the first to use this analysis to assess cognitive mechanisms and optimality of decisions underlying road crossing behaviour. We observed pedestrian behaviour in two city centres: Inuyama (Japan) and Strasbourg (France). In each city, observations were made at a safe site consisting of a crosswalk and a street light and at an unsafe site (i.e. no crosswalk or street light). At the unsafe site, we measured the time needed by a pedestrian to take a decision (T_dec). During T_dec, a pedestrian estimates whether he can (T_safe) or cannot (T_risk) cross the road. Using survival analysis, we studied the distributions of these three time variables and showed that French pedestrians took more risks than Japanese pedestrians, and that males took more risks than females, but only in Japan. More studies would considerably broaden our understanding on how culture may affect decision-making processes under risky circumstances.     

An Examination of the Trade Study Process at NASA

Abstract:

Engineering managers increasingly rely on trade study processes to design optimum system architectures. Opinions on what constitutes a quality trade study differ, and this can hinder the engineering manager in determining what trade study processes to follow. This article contributes to the manager's body of knowledge by identifying trade study best practices through reviews of published research and interviews with engineers who conducted successful trade studies supporting the design of complex space systems.

A checklist of trade study best practices was developed. Three completed NASA trade studies were then evaluated against the checklist in conjunction with interviews of engineers involved in the studies. Through one-on-one interviews with engineers, assessments were made on the value, appropriateness, and effectiveness of each trade study. Key issues, taken from the checklist, were addressed and the lessons learned were identified. The goal of the study was to establish the groundwork for a more detailed analysis of trade study processes. The engineering manager can use these preliminary findings to ensure that their trade study processes are timely, set up properly, and contain needed checks and balances.     

基于不对称信息的闭环供应链激励机制

运用委托代理理论,分别对制造商能获得回收市场真实信息和无法获得真实信息两种情况,设计了提供给第三方的线性合同的,并基于报童模型给出了制造商的最优生产决策.最后用仿真试验研究了市场情况以及回收量与需求的波动对制造商利润的影响.     

Optimizing infrastructure network maintenance when benefits are interdependent

Network Topology Dependencies (NTD) are a class of externalities in the maintenance cost structure of infrastructure networks with applications to many network industries, including natural gas and water distribution pipelines. It is shown that the above externalities may be included to infrastructure maintenance decisions, if optimal maintenance is formulated as a Rhys-Balinski selection problem. A unique contribution is that this risk management problem is analyzed from the point of view of integrating quantitative analysis to organizational and inter-organizational decision processes. Hence, the importance of various procedural requirements is established in addition to computational efficiency and numerical accuracy. In particular, the benefits of sensitivity analysis facilitation and of avoiding manipulability are stressed. The proposed solution process achieves all four requirements. Special attention is paid to the role of submodularity and antitone differences in sensitivity analysis.This complete issue was revised and published online in November 2004. The previous version contained a false date. Correspondence to: Ioannis S. Papadakis     

Toward a more ethical clinical trial

Summary Current methods of conducting clinical trials require the patient to agree to have his treatment assigned randomly, where his individual characteristics are taken into account only to balance the treatment groups. A Bayesian alternative involves eliciting the prior opinions of the group of clinicians who designed the study. Each patient is then guaranteed that the treatment he will receive is the best for him either in the opinion of at least one individual clinician or as a consensus of several, given the patient’s characteristics and all the information available from the trial when the assignment is made.     

Mind the gap: training road users to use speed and distance when making gap-acceptance decisions

Accurate gap-acceptance decisions require individuals to take into account both the distance to and the speed of an oncoming vehicle. The aim of the present studies was to develop an intervention that could successfully teach road users to focus on speed as well as distance. Across three studies, participants judged whether it was safe to cross the road or not when an oncoming vehicle was approaching from different distances and at different speeds. Study 1 trialed two techniques (“standard feedback” versus “three-look”) aimed at improving gap judgments. Standard feedback involved telling participants what the actual speed of a car was after they had made an estimate, whereas the three-look technique required participants to make timed and controlled head movements when scanning the road environment. Only standard feedback increased the participants’ mean gap-acceptance accuracy (assessed using both verbal and behavioral response measures). Study 2 also trialed two techniques, the standard feedback intervention used in Study 1, and a “two-response” intervention in which participants judged whether the oncoming vehicle was traveling at an atypical or normal speed. Study 2 found the two-response intervention to be more promising than the standard feedback procedure. Finally, Study 3 used video footage of oncoming vehicles to train younger (18–27 years) and older (60–80 years) adults and found the two-response intervention to be successful at improving gap-acceptance accuracies for both age groups. However, the intervention also resulted in more conservative gap judgments from participants in the older population independent of improvements in accuracy.     

Reliability and decomposition techniques to solve certain class of stochastic programming problems

Reliability based techniques has been an area of active research in structural design during the last decade, and different methods have been developed. The same has occurred with stochastic programming, which is a framework for modeling optimization problems involving uncertainty. The discipline of stochastic programming has grown and broadened to cover a wide range of applications, such as agriculture, capacity planning, energy, finance, fisheries management, production control, scheduling, transportation, water management, etc., and because of this, techniques for solving stochastic programming models are of great interest for the scientific community. This paper presents a new approach for solving a certain type of stochastic programming problems presenting the following characteristics: (i) the joint probability distributions of random variables are given, (ii) these do not depend on the decisions made, and (iii) random variables only affect the objective function. The method is based on mathematical programming decomposition procedures and first-order reliability methods, and constitutes an efficient method for optimizing quantiles in high-dimensional settings. The solution provided by the method allows us to make informed decisions accounting for uncertainty.     

Integrating objective and subjective hazard risk in decision-aiding system design

A generalized model is presented to incorporate objective (hard) and subjective (soft) hazard information in automated decision-aiding systems. The model may be used with more than one hazard, of more than one type, in a given problem. Uncertainties in state measurements, dynamics, hazard extent, and hazard severity are included, as is the consideration of the fact that different operators may have different concepts of what is an acceptable or unacceptable risk. By examining the tradeoffs created by these uncertainties, appropriate decision thresholds can be selected. Using an aviation case study, information gained from observation of aircraft behavior in the presence of weather was used to develop a model of weather as a soft hazard. This information can then be used in a decision aid to provide feedback on route acceptability.     

Ambiguity Aversion in Engineers

This article explores whether engineers exhibit the cognitive bias Ambiguity Aversion. Ambiguity Aversion, in which individuals prefer an unambiguous option to an objectively equal or superior ambiguous option, has been previously demonstrated to exist in the general population in decision research. The research presented here was performed by conducting Ambiguity Aversion experiments from prior research in a sample including roughly equivalent numbers of engineers and non-engineers. This research demonstrates that engineers do exhibit Ambiguity Aversion and that they do so to a significantly greater degree than the general population. This finding may have significant implications for both researchers and practitioners.     

Model selection for a class of stochastic processes or random fields with bounded range

Methods are developed for finding an optimal model for a non-Gaussian stationary stochastic process or homogeneous random field under limited information. The available information consists of: (i) one or more finite length samples of the process or field; and (ii) knowledge that the process or field takes values in a bounded interval of the real line whose ends may or may not be known. The methods are developed and applied to the special case of non-Gaussian processes or fields belonging to the class of beta translation processes. Beta translation processes provide a flexible model for representing physical phenomena taking values in a bounded range, and are therefore useful for many applications. Numerical examples are presented to illustrate the utility of beta translation processes and the proposed methods for model selection.     

Decision making and personality in traffic offenders: a study of Israeli drivers

Traffic offences present danger to the offender, and to others. This study examines differences in decision making and personality between traffic offenders and non-offenders. Fifty-one traffic offenders participating in penalty courses were compared to a control group of 36 drivers who were not penalized for traffic offences in the 5 years prior to the study. All participants performed the Iowa Gambling Task (IGT), a popular decision task employed for assessing cognitive impulsivity, and completed the "big five" personality questionnaire. The results showed that traffic offenders made fewer advantageous choices on the IGT; and an analysis with a formal cognitive model, the Expectancy Valance model, suggests that this results from offenders' high weighting of gains compared to losses. An examination of personality factors reveals that traffic offenders were more extraverted. The predictive power of IGT performance was comparable to that of the personality factor. These results demonstrate that the IGT can be useful for studying individual differences in risk taking in a real-world task, and combined with the EV model, identify the sources of these differences.     

An analytical approach to quantitative effect estimation of operation advisory system based on human cognitive process using the Bayesian belief network

The design of instrumentation and control (I&C) systems for nuclear power plants (NPPs) is rapidly moving towards fully digital I&C systems and is trending towards the introduction of modern computer techniques into the design of advanced main control rooms (MCRs) of NPPs. In the design of advanced MCRs, human–machine interfaces have improved and various types of decision support systems have been developed. It is important to design highly reliable decision support systems in order to adapt them in actual NPPs. In addition, to evaluate decision support systems in order to validate their efficiency is as important as to design highly reliable decision support systems. In this paper, an operation advisory system based on the human cognitive process is evaluated in order to estimate its effect. The Bayesian belief network model is used in the evaluation of the target system, and a model is constructed based on human reliability analysis event trees. In the evaluation results, a target system based on the operator's cognitive process showed better performance compared to independent decision support systems.     

A hybrid approach for concurrent layout design of cells and their flow paths in a tree configuration

The layout design of multiple-cell automated manufacturing systems includes cell layout design and flow path layout design. Traditional layout methods often treat these two as separate problems and the sequence for solving them is usually cell layout first and flow path layout later. However, approaches of these kinds have one major drawback, that is, they may produce cell layouts that are awkward or difficult for designers to conduct flow path layouts, or cell layouts that do not turn out to be as good as expected after flow path layouts have been performed. Other drawbacks of traditional layout methods include irregular shapes of cells, inaccurate calculations of flow distances, etc. This paper addresses the layout problem of cells and their connecting flow paths in a tree configuration. The proposed layout procedure is designed to avoid the aforementioned drawbacks of traditional layout methods by emphasizing concurrent layout design of cells and flow paths. It combines a search algorithm and mathematical programming models. The search algorithm has a backtracking procedure that allows one to explore alternative layouts, while the mathematical programming models help one obtain accurate layouts of cells and flow paths. The proposed layout procedure also interacts with designers and allows designers to include their qualitative consideration into the layout design. As a result, one can obtain more accurate and good-quality layouts with the proposed layout procedure.     

A template approach to manage mould-testing stage in a plastic injection mould project

Two major tasks are involved in the mould-testing process stage for any mould project: (a) to troubleshoot and make decisions during the internal/external mould-testing; and (b) to perform dimensional inspection of satisfactory moulded parts. In any plastic injection mould industries, the mould-testing process stage is often the most hectic. The main reasons behind the buzz of activities are that enormous amounts of data need to be sorted and managed and decisions have to be made dynamically. The mould-making industries also rely heavily on field experts during the decision-making of the mould-testing process stage. It is both time-consuming and unproductive to manage the large amount of data, and sending field experts overseas to oversee the mould-testing and to make decisions is an expensive fraction on the company's expenses. The template approach can be executed to overcome the problems faced. The reason being that the expertise on the decision-making during the mould-testing is not unique. These expertises can easily be consolidated into a knowledge database and novice personnel could simply obtain the information from there and make similar decisions as the field experts. This template approach also offers an avenue to manage the data systematically through a proper channel of recording the necessary information without duplication. A case study was also presented to demonstrate the use of templates in managing the mould-testing stage of a mould project.     

Age-related differences in street-crossing decisions: the effects of vehicle speed and time constraints on gap selection in an estimation task

Two experiments were conducted to study how age affects street-crossing decisions in an estimation task, with particular emphasis on how oncoming vehicle speed and a time constraint influence the time gap deemed acceptable for crossing. Experiment 1 showed that when there was a time constraint, all age groups selected a shorter time gap for the higher speed. This was associated with a large number of missed opportunities for the low speed and many unsafe decisions for the high speed. In the second experiment, which had no time constraint, young pedestrians operated in a constant-time mode regardless of speed, whereas older pedestrians accepted shorter and shorter time gaps as speed increased. The results seem to indicate that the effect of speed is due to a mixed operating mode of participants, whose decisions may be based on either time or vehicle distance, depending on the task requirements and on the participant's own ability to meet those requirements.