A combined multitasking performance measure involving sequential and parallel task executions

Cognition, Technology & Work - Research on human multitasking suggests several measures to evaluate performance. However, the suggested measures evaluate performance either when tasks are...     

Security threats scenarios in trust and reputation models for distributed systems

Trust and reputation management over distributed systems has been proposed in the last few years as a novel and accurate way of dealing with some security deficiencies which are inherent to those environments. Thus, many models and theories have been developed in order to effective and accurately manage trust and reputation in those communities. Nevertheless, very few of them take into consideration all the possible security threats that can compromise the system. In this paper, we present some of the most important and critical security threats that could be applied in a trust and reputation scheme. We will describe and analyze each of those threats and propose some recommendations to face them when developing a new trust and reputation mechanism. We will also study how some trust and reputation models solve them. This work expects to be a reference guide when designing secure trust and reputation models.     

Task priority reduces an adverse effect of task load on automation trust in a dynamic multitasking environment

Cognition, Technology & Work - The present study examined how task priority influences operators’ scanning patterns and trust ratings toward imperfect automation. Previous research...     

Modular analysis and modelling of risk scenarios with dependencies

The risk analysis of critical infrastructures such as the electric power supply or telecommunications is complicated by the fact that such infrastructures are mutually dependent. We propose a modular approach to the modelling and analysis of risk scenarios with dependencies. Our approach may be used to deduce the risk level of an overall system from previous risk analyses of its constituent systems. A custom made assumption-guarantee style is put forward as a means to describe risk scenarios with external dependencies. We also define a set of deduction rules facilitating various kinds of reasoning, including the analysis of mutual dependencies between risk scenarios expressed in the assumption-guarantee style.     

Automation failures on tasks easily performed by operators undermine trust in automated aids

OBJECTIVE: We tested the hypothesis that automation errors on tasks easily performed by humans undermine trust in automation. BACKGROUND: Research has revealed that the reliability of imperfect automation is frequently misperceived. We examined the manner in which the easiness and type of imperfect automation errors affect trust and dependence. METHOD: Participants performed a target detection task utilizing an automated aid. In Study 1, the aid missed targets either on easy trials (easy miss group) or on difficult trials (difficult miss group). In Study 2, we manipulated both easiness and type of error (miss vs. false alarm). The aid erred on either difficult trials alone (difficult errors group) or on difficult and easy trials (easy miss group; easy false alarm group). RESULTS: In both experiments, easy errors led to participants mistrusting and disagreeing more with the aid on difficult trials, as compared with those using aids that generated only difficult errors. This resulted in a downward shift in decision criterion for the former, leading to poorer overall performance. Misses and false alarms led to similar effects. CONCLUSION: Automation errors on tasks that appear "easy" to the operator severely degrade trust and reliance. APPLICATION: Potential applications include the implementation of system design solutions that circumvent the negative effects of easy automation errors.     

The effect of risk on trust attitude and trust behavior in interaction with information and decision automation

Situational risk has been postulated to be one of the most important contextual factors affecting operator’s trust in automation. However, experimentally, it has received only little attention and was directly manipulated even less. To close this gap, this study used a virtual reality multi-task environment where the main task entailed making a diagnosis by assessing different parameters. Risk was manipulated via the altitude, the task was set in including the possibility of virtually falling in case of a mistake. Participants were aided either by information or decision automation. Results revealed that trust attitude toward the automation was not affected by risk. While trust attitude was initially lower for the decision automation, it was equally high in both groups at the end of the experiment after experiencing reliable support. Trust behavior was significantly higher and increased during the experiment for the decision automation supported group in the form of less automation verification behavior. However, this detrimental effect was distinctly attenuated under high risk. This implies that negative consequences of decision automation in the real world might have been overestimated by studies not incorporating risk.

     

Evaluating transaction trust and risk levels in peer-to-peer e-commerce environments

Trust evaluation is critical to peer-to-peer (P2P) e-commerce environments. Traditionally the evaluation process is based on other peers' recommendations neglecting transaction amounts. This may lead to the bias in transaction trust evaluation and risk the new transaction. The weakness may be exploited by dishonest sellers to obtain good transaction reputation by selling cheap goods and then cheat buyers by selling expensive goods. In this paper we present a novel model for transaction trust evaluation, which differentiates transaction amounts when computing trust values. The trust evaluation is dependent on transaction history, the amounts of old transactions, and the amount of the new transaction. Therefore, the trust value can be taken as the risk indication of the forthcoming transaction and is valuable for the decision-making of buyers.     

一种基于风险和推荐的用户信任计算方法

结合客观的风险评估和主观的推荐信任共同计算用户可信度,并利用推荐可信度和域可信度来识别和惩罚提供虚假反馈的服务方,提出了基于风险和推荐的用户信任计算方法。仿真实验表明,该模型具有较好的动态适应性,能够准确反映用户行为,为信任决策提供安全、可靠的依据。     

Analysis of dynamic control strategies of an FMS under different scenarios

This paper presents a simulation study aimed at evaluating the performances of a flexible manufacturing system (FMS) in terms of makespan, average flow time, average delay time at local buffers and average machine utilization, subject to different control strategies which include routing flexibilities and dispatching rules. The routing strategies under evaluation are ‘no alternative routings’; ‘alternative routings dynamic’; and ‘alternative routings planned’. Above routing strategies are combined with seven dispatching rules, and studied in different production volume which varies from 50 to 500 parts. In addition, impacts of both infinite and finite local buffer capacities are analyzed. Since an FMS usually deals with a variety of products, effects of changing the part mix ratio are also discussed. Finally, machine failure is also introduced in this research to study the effects of machine reliability on the system. Simulation results indicate that the ‘alternative routings planned’ strategy outperforms other routing strategies if the local buffer size is infinity. However, there is no particular dispatching rule that performs well in all buffer size settings but infinity buffer size is not the best choice with respect to the four performance measures. In addition, the four performance measures, except machine utilization, under different control strategies seem quite insensitive to the variation in part mix ratios.     

Hierarchical and multi-featured fusion for effective gait recognition under variable scenarios

Human identification by gait analysis has attracted a great deal of interest in the computer vision and forensics communities as an unobtrusive technique that is capable of recognizing humans at range. In recent years, significant progress has been made, and a number of approaches capable of this task have been proposed and developed. Among them, approaches based on single source features are the most popular. However, the recognition rate of these methods is often unsatisfactory due to the lack of information contained in single feature sources. Consequently, in this paper, a hierarchal and multi-featured fusion approach is proposed for effective gait recognition. In practice, using more features for fusion does not necessarily mean a better recognition rate and features should in fact be carefully selected such that they are complementary to each other. Here, complementary features are extracted in three groups: Dynamic Region Area; Extension and Space features; and 2D Stick Figure Model features. To balance the proportion of features used in fusion, a hierarchical feature-level fusion method is proposed. Comprehensive results of applying the proposed techniques to three well-known datasets have demonstrated that our fusion-based approach can improve the overall recognition rate when compared to a benchmark algorithm.     

The impact of trust,risk and optimism bias on E-file adoption

One of congress’ goals for 2007 was for 80% of all tax and informational returns to be filed electronically. However, to date that lofty goal has fallen well short. This research proposes a model of e-filing adoption. To test the model a survey is administered to 260 participants. The instrument assesses citizen perceptions of trust, risk and optimism bias. Structural equation modeling is used to evaluate the relationships between these three concepts and intention to use. The results indicate that trust of the Internet, trust of the e-filer, perceived risk and optimism bias all have an impact on intention to use e-filing. Implications for practice and research are discussed.     

异构环境下企业集成自动化系统的实现

分析了传统的企业集成自动化系统,重点讨论了现场级和车间级,指出了存在的主要问题,并分别针对现场级和车间级提出了新的解决方案.     

Multi-criteria analysis of wastewater treatment plant design and control scenarios under uncertainty

Wastewater treatment plant control and monitoring can help to achieve good effluent quality, in a complex, highly non-linear process. The Benchmark Simulation Model no. 2 (BSM2) is a useful tool to competitively evaluate plant-wide control on a long-term basis.A method to conduct scenario analysis of process designs by means of Monte Carlo (MC) simulations and multi-criteria evaluation is presented. It is applied to the open loop version of BSM2 and to two closed loop versions, one with a simple oxygen controller and the other one with an ammonium controller regulating the set-point of the oxygen controller (cascade controller). The results show a much greater benefit of the cascade controller compared to the simple controller, both in environmental and economic terms. From an optimal process design point of view, the results show that the volume of the primary clarifier and the anoxic fraction of the reactor volume have an important impact on process performance.The uncertainty analysis of the optimal designs, also performed with MC simulations, highlights the improved and more stable effluent under closed loop control.     

异构环境下企业集成自动化系统的实现

分析了传统的企业集成自动化系统，重点讨论了现场级和车间级，指出了存在的主要问题，并分别针对现场级和车间级提出了新的解决方案。     

Investigating online information disclosure: Effects of information relevance,trust and risk

Organizations rely on customer information to design new products and offer new services. However, people should not share their personal information online. We produced and tested a model of information disclosure. While prior work focused on the effects of trust and its relationship to risk in determining intent to disclose information, we assumed that information relevance was a critical antecedent to disclosure and that both relevance and trust could alleviate perceptions of risk associated with disclosure, thereby increasing peoples’ intentions to disclose information. We tested our model using 264 subjects in an experimental setting. The results showed the importance of relevance on intentions to disclose information – allowing us to draw implications for practice about voluntary information disclosure in online settings.     

Endurance: A new robustness measure for complex networks under multiple failure scenarios

Society is now, more than ever, highly dependent on the large-scale networks that underpin its functions. In relatively recent times, significant failures have occurred on large-scale networks that have a considerable impact upon sizable proportions of the world’s inhabitants. The failure of infrastructure has, in turn, begot a subsequent loss of services supported by that network. Consequently, it is now vitally important to evaluate the robustness of such networks in terms of the services supported by the network in question. Evaluating network robustness is integral to service provisioning and thus any network should include explicit indication of the impact upon service performance. Traditionally, network robustness metrics focused solely on topological characteristics, although some new approaches have considered, to a degree, the services supported by such networks. Several shortcomings of these new metrics have been identified. With the purpose of solving the drawbacks of these metrics, this paper presents a new measure called endurance, which quantifies the level of robustness supported by a specific topology under different types of multiple failure scenarios, giving higher importance to perturbations affecting low percentages of elements of a network. In this paper, endurance of six synthetic complex networks is computed for a range of defined multiple failure scenarios, taking into account the connection requests that cannot be satisfied. It is demonstrated that our proposal is able to quantify the robustness of a network under given multiple failure scenarios. Finally, results show that different types of networks react differently depending on the type of multiple failure.     

办公自动化环境下医院档案管理探讨

档案管理在医院管理工作中占有重要地位,医院的行政管理、人事管理、病例档案管理等都需进行科学规范化分类管理。互联网技术的飞速发展创新和改革档案管理方式,高效档案管理方式能提升医院的整体管理水平,促进医院全面改革创新发展的方向。本文将以医院档案管理工作实现办公自动化情况分析,提出办公自动化医院档案管理可行性建议。     

A Methodology of Automation Cost Assessment under Given Defective Products Probability

A methodology for determining the optimal automation scheme ensuring minimum component manufacture cost subject to defective products probability is developed. The algorithm proposed eliminates the need in the exhaustive search of possible solutions.