Measurement of slipperiness: fundamental concepts and definitions.

The main objective of this paper is to give an overview of basic concepts and definitions of terms related to the 'measurement of slipperiness' from the onset of a foot slide to a gradual loss of balance and a fall. Other unforeseen events prior to falls (e.g. tripping) are sparingly dealt with. The measurement of slipperiness may simply comprise an estimation of slipping hazard exposures that initiate the chain of events ultimately causing an injury. However, there is also a need to consider the human capacity to anticipate slipperiness and adapt to unsafe environments for avoiding a loss of balance and an injury. Biomechanical and human-centred measurements may be utilized for such an approach, including an evaluation of relevant safety criteria for slip/fall avoidance and procedures for validation of slip test devices. Mechanical slip testing approaches have been readily utilized to measure slipperiness in terms of friction or slip resistance but with conflicting outcomes. An improved understanding of the measurement of slipperiness paradigm seems to involve an integration of the methodologies used in several disciplines, among others, injury epidemiology, psychophysics, biomechanics, motor control, materials science and tribology.     

The role of friction in the measurement of slipperiness,Part 1: Friction mechanisms and definition of test conditions

Friction has been widely used as a measure of slipperiness. However, controversies around friction measurements remain. The purposes of this paper are to summarize understanding about friction measurement related to slipperiness assessment of shoe and floor interface and to define test conditions based on biomechanical observations. In addition, friction mechanisms at shoe and floor interface on dry, liquid and solid contaminated, and on icy surfaces are discussed. It is concluded that static friction measurement, by the traditional use of a drag-type device, is only suitable for dry and clean surfaces, and dynamic and transition friction methods are needed to properly estimate the potential risk on contaminated surfaces. Furthermore, at least some of the conditions at the shoe/floor interface during actual slip accidents should be replicated as test conditions for friction measurements, such as sliding speed, contact pressure and normal force build-up rate.     

Community resilience and flooding in UK guidance: A critical review of concepts,definitions, and their implications

Community resilience is one of the main strategies that UK governments employ to deal with the impact of floods. In this paper, we analyse how community resilience is used in 28 UK guidance documents that refer to floods and discuss the benefits and drawbacks of different conceptualizations. We show that some documents represent community resilience as the absence of illness, as the opposite of vulnerability, as a static and unchanging element, or in a circular way as both a cause and an outcome. By contrast, some documents avoid generalizations and focus more specifically on the concept's behavioural, relational, cognitive, and psychological aspects. We discuss the implications of different conceptualizations of community resilience for its operationalization by policymakers and practitioners.     

基于目标驱动与活动的软件过程度量模型的改进

根据已有的目标驱动与活动相结合的度量模型GIAM-D,进行了进一步完善扩展形成EGIAM-D模型.建立EGIAM-D的统一度量标识库,通过对度量各集定义的精简和合并达到整个度量过程的半自动化,并给出相应的算法.     

Been There,Seen That: Visualization of Movement and 3D Eye Tracking Data from Real-World Environments

The distribution of visual attention can be evaluated using eye tracking, providing valuable insights into usability issues and interaction patterns. However, when used in real, augmented, and collaborative environments, new challenges arise that go beyond desktop scenarios and purely virtual environments. Toward addressing these challenges, we present a visualization technique that provides complementary views on the movement and eye tracking data recorded from multiple people in real-world environments. Our method is based on a space-time cube visualization and a linked 3D replay of recorded data. We showcase our approach with an experiment that examines how people investigate an artwork collection. The visualization provides insights into how people moved and inspected individual pictures in their spatial context over time. In contrast to existing methods, this analysis is possible for multiple participants without extensive annotation of areas of interest. Our technique was evaluated with a think-aloud experiment to investigate analysis strategies and an interview with domain experts to examine the applicability in other research fields.     

Challenges of real-world reinforcement learning: definitions,benchmarks and analysis

Machine Learning - Reinforcement learning (RL) has proven its worth in a series of artificial domains, and is beginning to show some successes in real-world scenarios. However, much of the research...     

Learning basic concepts of telecommunications: An experiment in multimedia and learning

This paper reports on learning as it is related to use of a multimedia-based tutorial. The tutorial is designed to teach basic concepts of telecommunications to University students. The experiment described analyzes test scores of two sets of students, the first group using the aforementioned tutorial and the second learning in a traditional setting. Although learning, in both cases, occurs, there is no significant difference between the amount learned by students in the control group and those in the experimental group.     

教育艾真体的免疫机制及其应用

对艾真体技术的发展比较研究,提出了教育艾真体的免疫机制,克服旧艾真体的不足,增强其鲁棒性、安全性和智能性。建立人工免疫机制及其算法后,创建教育艾真体系统的模型,分析其原理、结构和特点,并讨论分布和并行环境中教育多艾真体系统的计算以及鲁棒归约方法。之后还对免疫算法做出仿真。最后讨论了基于免疫机制的教育艾真体的应用原型及其前景,再得出一些结论。     

A mosaic of Chu spaces and Channel Theory I: Category-theoretic concepts and tools

Chu Spaces and Channel Theory are well-established areas of investigation in the general context of category theory when applied to semantically-based information flow. In this Part I of a two-part work, we review a range of related concepts and examples showing how these methods can be applied to logic and computer science, including Formal Concept Analysis, distributed systems and ontology development. We also discuss spatial coarse-graining in relationship to information, and in this direction we establish some basic simplicial and categorical techniques which will supplement the other methods of this Part I when they are applied to characterise visual object identification and the inference of mereological (i.e. part-whole) complexity in Part II.     

Safety leadership and systems thinking: application and evaluation of a Risk Management Framework in the mining industry

Abstract

Safety leadership is an important factor in supporting safety in high-risk industries. This article contends that applying systems-thinking methods to examine safety leadership can support improved learning from incidents. A case study analysis was undertaken of a large-scale mining landslide incident in which no injuries or fatalities were incurred. A multi-method approach was adopted, in which the Critical Decision Method, Rasmussen’s Risk Management Framework and Accimap method were applied to examine the safety leadership decisions and actions which enabled the safe outcome. The approach enabled Rasmussen’s predictions regarding safety and performance to be examined in the safety leadership context, with findings demonstrating the distribution of safety leadership across leader and system levels, and the presence of vertical integration as key to supporting the successful safety outcome. In doing so, the findings also demonstrate the usefulness of applying systems-thinking methods to examine and learn from incidents in terms of what ‘went right’. The implications, including future research directions, are discussed.

Practitioner Summary: This paper presents a case study analysis, in which systems-thinking methods are applied to the examination of safety leadership decisions and actions during a large-scale mining landslide incident. The findings establish safety leadership as a systems phenomenon, and furthermore, demonstrate the usefulness of applying systems-thinking methods to learn from incidents in terms of what ‘went right’. Implications, including future research directions, are discussed.     

Mixed finite element methods — Reduced and selective integration techniques: A unification of concepts

The equivalence of certain classes of mixed finite element methods with displacement methods which employ reduced and selective integration techniques is established. This enables one to obtain the accuracy of the mixed formulation without incurring the additional computational expense engendered by the auxiliary field of the mixed method. Applications and numerical examples are presented for problems with constraints which can be difficult to enforce in finite element approximations and have often dictated the use of mixed principles. These include thin beams and plates, and linear and nonlinear incompressible and nearly incompressible continuum problems in solid and fluid mechanics.     

Passive and active navigation of virtual environments vs. traditional printed evacuation maps: A comparative evaluation in the aviation domain

Printed maps are the most common tool to prepare people for emergency evacuation in contexts such as public buildings or transportation. Unfortunately, they are poorly understood and often ignored by people. Virtual environments (VEs) could be a more effective method to support people in acquiring spatial knowledge about the real-world environment to evacuate. This paper pursues three main goals. First, we propose a VE-based tool to support spatial knowledge acquisition for evacuation purposes, using aviation as a real-world domain in which such knowledge is crucial for passengers’ safety. Second, we study in detail one of the VE design choices (active or passive navigation), comparing a version of our tool in which users navigate by actively controlling their position with another version in which users are passively led along pre-defined routes. Third, we contrast the two versions of the tool with the traditional, printed diagrammatic map provided to passengers by airlines. Results of our study show that the VE-based approach produces objectively better spatial knowledge when users are asked to pinpoint their assigned position in the environment, and that active navigation produces a performance improvement in a subsequent virtual evacuation. Moreover, the VE-based approach is perceived as more enjoyable, easier to comprehend and more effective than printed maps when active navigation is available.     

Whole-body vibration: Measurement of horizontal and vertical transmissibility of an agricultural tractor seat

The seats may significantly reduce the exposures levels transmitted to the driver, but the European Directive 2002/44/EC (2002) requires only tests on the damping seat capacity along the vertical direction, whereas nothing is required for the longitudinal and transversal directions.Field tests were carried out using a 93 kW tractor to verify the vibrational comfort values given by seat with pneumatic suspension. The tests were executed with the tractor running on different surfaces, at two different forward speed and tire pressures and with different tractor masses. Three repetition were carried out for each configuration. Accelerations were always measured on both the seat and the cabin platform and the calculations were done using the ISO 2631 standard suggestions. The vibration total values and the acceleration transmissibility along the 3 perpendicular axes were calculated and analysed.Despite different boundary conditions (surface, tire pressure, forward speed and tractor mass distribution), along the Z axis the transmissibility was constantly around 0.7, to confirm that the seat worked well to damp the vertical exposures. Different were the situations for the X and the Y axes. Excluding the asphalt, on the other crossed surfaces high transmissibility values were observed (never less than 1), especially along the X axis.Relevance to industry. This paper describes the vibration transmissibility of an agricultural tractor seat. Tests were carried out with the tractor running on different surfaces and with different configurations. The seat transmissibility along the three orthogonal directions was acquired.Results suggest that the tractor manufacturer should consider, during the machine design, also the rolling and pitching movements, because the seat accelerations along the X and Y axes are influenced by them. The seat manufacturer could reduce the rolling and pitching effects using specific suspension systems along the horizontal and lateral directions.     

A unique algorithm for the assessment and improvement of job satisfaction by resilience engineering: Hazardous labs

There are many potential dangers in laboratories of universities. Hence it should be focused on the actions and decisions of the individuals who work in the labs. Resilience Engineering (RE), the ability to recover quickly after an upset, is known as an important feature of a complex system which handles hazardous technical operations. In response to the need for the betterment of health, safety, and environment (HSE) at work; it is felt necessary to study the RE aspects if an unexpected events occurs. The main purpose of this study is to determine the role and effect of RE in improving job satisfaction and occupational safety in laboratories of universities. This study also presents an intelligent algorithm for assessing and improving job satisfaction in laboratories filled with hazardous materials by means of HSE and RE. In doing so, questionnaires related to HSE and RE are filled in by laboratory operators. The average result of each HSE and RE category is considered as input and job satisfaction as output for the proposed algorithm. An integrated neuro-fuzzy algorithm to find optimal solution is developed and tested for the purpose of this study. Also, results are tested and verified by regression analysis. Finally, with the help of Normal probability technique, outlier laboratories will be identified. The results are improved by means of RE as an input. This is one of the first studies introducing an intelligent algorithm for the improvement of job satisfaction by means of RE and HSE in hazardous laboratories.     

Cognitive Theories and Engineering Approaches for Safety Assessment and Design of automated systems: A Case Study of a Power Plant

This paper concerns methods and techniques for analysis and assessment of human factors in automated plant. A well-known theory is reviewed and an engineering approach is devised for retrospective accident evaluations and prospective studies. The lessons learnt from a serious accident for the safety assessment of a real plant are discussed in detail. The relevance of the human contribution to the accident and the likely improvements identified by the application of the method confirm the importance and advantages of performing accurate human factors analyses for design and safety of technological systems.     

Control and data abstraction: the cornerstones of practical formal verification

In spite of the impressive progress in the development of the two main methods for formal verification of reactive systems – Symbolic Model Checking and Deductive Verification, they are still limited in their ability to handle large systems. It is generally recognized that the only way these methods can ever scale up is by the extensive use of abstraction and modularization, which break the task of verifying a large system into several smaller tasks of verifying simpler systems. In this paper, we review the two main tools of compositionality and abstraction in the framework of linear temporal logic. We illustrate the application of these two methods for the reduction of an infinite-state system into a finite-state system that can then be verified using model checking. The technical contributions contained in this paper are a full formulation of abstraction when applied to a system with both weak and strong fairness requirements and to a general temporal formula, and a presentation of a compositional framework for shared variables and its application for forming network invariants.     

乙基甲基咪唑磷酸二乙酯+水/乙醇/甲醇二元溶液混合热及比热容的测量与关联

离子液体是一类新型绿色溶剂,具有蒸汽压极低,不挥发,不易燃,宽液程和良好的热稳定性,对许多有机物和无机物有良好的溶解性。前期的研究发现,离子液体乙基甲基咪唑磷酸二乙酯[EMIM][DEP]与H_2O、C_2H_5OH和CH_3OH有良好的溶解性,所构成的二元溶液表现出对拉乌尔定律显著的负偏差,这些性质使得离子液体[EMIM][DEP]有可能成为吸收制冷/热泵循环的新型吸收剂。二元工质溶液[EMIM][DEP]+H_2O/C_2H_OH/CH_3OH的混合热以及比热容是分析吸收制冷/热泵性能重要的热力学基础数据之一。本文采用绝热量热法对[EMIM][DEP]分别与水,乙醇和甲醇所构成的3个二元溶液体系,在25℃以及不同浓度下的混合热进行了测量,并采用Redlich-Kister方程对数据进行了关联。实验结果表明,[EMIM][DEP]与水,乙醇和甲醇的混合过程均为放热过程,混合热大小次序是H_2O>CH_3OH>C_2H_5OH。对3个二元溶液体系在不同温度和浓度下的比热容进行了测量,并采用浓度的多项式函数对其进行关联。结果发现,离子液体溶液的比热容随温度的增加而线性增加,随离子液体的含量增加而降低。