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1.
Yue Wei  Jiayue Zheng 《Ergonomics》2018,61(7):933-946
Visually induced motion sickness (VIMS) is a common discomfort response associated with vection-provoking stimuli. It has been suggested that susceptibility to VIMS depends on the ability to regulate visual performance during vection. To test this, 29 participants, with VIMS susceptibility assessed by Motion Sickness Susceptibility Questionnaire, were recruited to undergo three series of sustained attention to response tests (SARTs) while watching dot pattern stimuli known to provoke roll-vection. In general, SARTs performance was impaired in the central visual field (CVF), but improved in peripheral visual field (PVF), suggesting the reallocation of attention during vection. Moreover, VIMS susceptibility was negatively correlated with the effect sizes, suggesting that participants who were less susceptible to VIMS showed better performance in attention re-allocation. Finally, when trained to re-allocation attention from the CVF to the PVF, participants experienced more stable vection. Findings provide a better understanding of VIMS and shed light on possible preventive measures.

Practitioner Summary: Allocating less visual attention to central visual field during visual motion stimulation is associated with stronger vection and higher resistance to motion sickness. Virtual reality application designers may utilise the location of visual tasks to strengthen and stabilise vection, while reducing the potential of visually induced motion sickness.  相似文献   


2.
In this study we investigated the relationship between body movement during virtual reality (VR) analgesia and the experience of pain. Thermal (cold) stimulation was used to inflict pain. Two measures of pain were used—pain tolerance and pain intensity. Participants were wearing head mounted displays (Oculus Rift DK2) and were playing a game created by authors of the study.

Forty-six students of Wroclaw University participated in a within-subject design experiment. Each subject participated in a non-VR control condition and in two experimental conditions. Participants navigated the VR game using a computer mouse, but the mouse sensitivity (and therefore amount of physical movement necessary to navigate) was different in each experimental condition. We also measured feeling of presence in VR, game behavior, and attitudes toward the game.

The amount of body movement while steering the game was related to a decrease in pain intensity, but not in pain tolerance. This was an opposite result to our previously published experiment where we found an effect on pain tolerance but not on sensitivity. There was no significant correlation between presence and any of the pain measures.  相似文献   


3.
This study aimed to evaluate objective and subjective visual fatigue experienced before and after performing a visual task while using a head-mounted display for virtual reality (VR-HMD) and two-dimensional (2D) display. Binocular fusion maintenance (BFM) was measured using a binocular open-view Shack–Hartmann wavefront aberrometer equipped with liquid crystal shutters. Twelve healthy subjects performed the BFM test and completed a questionnaire regarding subjective symptoms before and after performing a visual task that induces low visually induced motion sickness (VIMS). BFM (p = .87) and total subjective eye symptom scores (p = .38) were not significantly different between both groups, although these values were significantly lower after the visual task than before the task within both groups (p < .05). These findings suggest that visual fatigue after using a VR-HMD is not significantly different from that after using a 2D display in the presence of low-VIMS VR content.

Practitioner summary: Objective and subjective evaluation of visual fatigue were not significantly different with the use of a head-mounted display for virtual reality (VR-HMD) and two-dimensional display. These results should be valuable not only to engineers developing VR content but also to researchers involved in the evaluation of visual fatigue using VR-HMD.

Abbreviations: VR: virtual reality; VR-HMD: head-mounted display for virtual reality; BFM: binocular fusion maintenance; BWFA: binocular open-view Shack–Hartmann wavefront aberrometer  相似文献   


4.
The present investigation evaluated the effects of virtual reality (VR) training on the performance, perceived workload and stress response to a live training exercise in a sample of Soldiers. We also examined the relationship between the perceptions of that same VR as measured by engagement, immersion, presence, flow, perceived utility and ease of use with the performance, workload and stress reported on the live training task. To a degree, these latter relationships were moderated by task performance, as measured by binary (Go/No-Go) ratings. Participants who reported positive VR experiences also tended to experience lower stress and lower workload when performing the live version of the task. Thus, VR training regimens may be efficacious for mitigating the stress and workload associated with criterion tasks, thereby reducing the ultimate likelihood of real-world performance failure.

Practitioner Summary: VR provides opportunities for training in artificial worlds comprised of highly realistic features. Our virtual room clearing scenario facilitated the integration of Training and Readiness objectives and satisfied training doctrine obligations in a compelling engaging experience for both novice and experienced trainees.  相似文献   


5.
The last few years have seen the development of Discrete Event-Dynamic Net Systems1,2 as instruments for modeling complex systems. They are able to achieve the following objectives:

—formality of the modeling methodology

—ability to model static and dynamic aspects

—ability to pass between levels of differently rich structures by morphisms

—uniform representation of the communication process as

—an information process

—a decision process and

—a control process

—homogeneity of the representation and modeling methods

—ability to derive qualitative and quantitative statements.

The foundation is provided by a Discrete Event-Dynamic Net System which includes the axiomatic declaration of general Petri nets. In order to calculate the structural and dynamic aspects, so-called Petri net machines are developed. It is shown that this approach can even be used to treat the following aspects:

—use of time during the process

—increase of costs during the generation and transportation of information

—augmentation, evaluation and transformation of information objects.

Recursive formulas are derived and some examples calculated.  相似文献   


6.
Many attempts1, 7, 8, 35 have been made to overcome the limit imposed by the Turing Machine34 to realise general mathematical functions and models of (physical) phenomena.

They center around the notion of computability.

In this paper we propose a new definition of computability which lays the foundations for a theory of cybernetic and intelligent machines in which the classical limits imposed by discrete algorithmic procedures are offset by the use of continuous operators on unlimited data. This data is supplied to the machine in a totally parallel mode, as a field or wave.

This theory of machines draws its concepts from category theory, Lie algebras, and general systems theory. It permits the incorporation of intelligent control into the design of the machine as a virtual element. The incorporated control can be realized in many (machine) configurations of which we give three:

a) a quantum mechanical realization appropriate to a possible understanding of the quantum computer and other models of the physical microworld,

b) a stochastic realization based on Kolmogorov-Gabor theory leading to a possible understanding of generalised models of the physical or thermodynamic macroworld, and lastly

c) a classical mechanical realization appropriate lo the study of a new class of robots.

Particular applications at a fundamental level are cited in geometry, mathematics, biology, acoustics, aeronautics, quantum mechanics, general relativity and. Markov chains. The proposed theory therefore opens a new way towards understanding the processes that underlie intelligence.  相似文献   


7.
The Problem

Internet of Things (IoT) is providing new services and insights by sensing contextual data but there are growing concerns of privacy risks from users that need immediate attention.

The Reason

The IoT devices and smart services can capture Personally Identifiable Information (PII) without user knowledge or consent. The IoT technology has not reached the desired level of maturity to standardize security and privacy requirements.

The Solution

IoT Privacy by Design is a user-centric approach for enabling privacy with security and safety as a ‘win-win’ positive outcome of IoT offerings, irrespective of business domain. The Proactive and Preventive Privacy (3P) Framework proposed in this paper should be adopted by the IoT stakeholders for building trust and confidence in end users about IoT devices and smart services.  相似文献   


8.
This paper is a study of an adaptive quality control system from a viewpoint of quality goal. The main purpose is to introduce a conceptual framework for setting up quality goals which are in accordance with the external environment and internal capacity of quality control systems. We apply a mathematical general systems approach.

The results of our paper are summarized as follows:

1)As important decision-making in adaptive QCS, the decision-making for estimalion of fitness and examination of attainability are proposed and formalized mathematically.

2)A refinement process is formalized in which models are revised according to the changes of market.

3)Basic steps for setting quality goals are obtained which are based on the above formalization.  相似文献   


9.
蔡豪  袁正道 《计算机应用》2020,40(6):1707-1713
针对如何从云数据中心的异常物理主机中选择出候选迁移虚拟机列表是虚拟机迁移中的问题,提出了基于贪心模式的虚拟机选择算法(GAO-VMS)。GAO-VMS每次都选择那些目标函数最优的虚拟机作为标准来迁移,形成候选迁移虚拟机列表,它有三类贪心模式:最大能量降低消耗策略(MPR)、最小迁移时间及能量消耗均衡策略(TPT)、最小每秒百万条指令数虚拟机请求策略(VVM)。使用CloudSim模拟器作为GAO-VMS的仿真环境。仿真结果表明:与常见的虚拟机迁移策略相比较,GAO-VMS使得云数据中心的能量消耗减少了30%~35%,虚拟机迁移次数减少了40%~45%,服务等级协议(SLA)违规率以及SLA违规和能量消耗联合指标只有5%的增加。GAO-VMS策略可用于企业构造绿色云计算中心。  相似文献   

10.
Few statistical models of rear seat passenger posture have been published, and none has taken into account the effects of occupant age. This study developed new statistical models for predicting passenger postures in the rear seats of automobiles. Postures of 89 adults with a wide range of age and body size were measured in a laboratory mock-up in seven seat configurations. Posture-prediction models for female and male passengers were separately developed by stepwise regression using age, body dimensions, seat configurations and two-way interactions as potential predictors. Passenger posture was significantly associated with age and the effects of other two-way interaction variables depended on age. A set of posture-prediction models are presented for women and men, and the prediction results are compared with previously published models. This study is the first study of passenger posture to include a large cohort of older passengers and the first to report a significant effect of age for adults. The presented models can be used to position computational and physical human models for vehicle design and assessment.

Practitioner Summary:

The significant effects of age, body dimensions and seat configuration on rear seat passenger posture were identified. The models can be used to accurately position computational human models or crash test dummies for older passengers in known rear seat configurations.  相似文献   


11.
This study examined the effect of passengers’ active head-tilt and eyes-open/eyes-closed conditions on the severity of motion sickness in the lateral acceleration environment of cars. In the centrifugal head-tilt condition, participants intentionally tilted their heads towards the centrifugal force, whereas in the centripetal head-tilt condition, the participants tilted their heads against the centrifugal acceleration. The eyes-open and eyes-closed cases were investigated for each head-tilt condition. In the experimental runs, the sickness rating in the centripetal head-tilt condition was significantly lower than that in the centrifugal head-tilt condition. Moreover, the sickness rating in the eyes-open condition was significantly lower than that in the eyes-closed condition. The results suggest that an active head-tilt motion against the centrifugal acceleration reduces the severity of motion sickness both in the eyes-open and eyes-closed conditions. They also demonstrate that the eyes-open condition significantly reduces the motion sickness even when the head-tilt strategy is used.

Practitioner Summary: Little is known about the effect of head-tilt strategies on motion sickness. This study investigated the effects of head-tilt direction and eyes-open/eyes-closed conditions on motion sickness during slalom automobile driving. Passengers’ active head tilt towards the centripetal direction and the eyes-open condition greatly reduce the severity of motion sickness.  相似文献   


12.
Background: Smartphones have reached levels of popularity and penetration where they are now suitable for use in population health interventions. A key feature of smartphones is push notification or in app messaging service, which can be used to alert users to messages or instructions pertaining to an installed app. Little evidence exists as to the persuasive power of these messages.

Method: We conducted a 24-week live user evaluation of push notifications used in a behavior-based mobile app for a meal replacement program to understand the role of push notifications in persuading users to engage with self-monitoring tasks.

Results: User perception of the prompts were verified through questionnaires, which in conjunction with the interaction logs show that users were tolerant of multiple daily prompts. The decline in compliance to the tasks set, however, shows that while the participants did not object to receiving prompts, they were less likely to respond to them as the study progressed.

Conclusions: Push notifications and user tasks are appropriate mechanisms to engage users with mobile technology in the short term.  相似文献   


13.
The aim of this review was to provide an overview of assistive exoskeletons that have specifically been developed for industrial purposes and to assess the potential effect of these exoskeletons on reduction of physical loading on the body. The search resulted in 40 papers describing 26 different industrial exoskeletons, of which 19 were active (actuated) and 7 were passive (non-actuated). For 13 exoskeletons, the effect on physical loading has been evaluated, mainly in terms of muscle activity. All passive exoskeletons retrieved were aimed to support the low back. Ten-forty per cent reductions in back muscle activity during dynamic lifting and static holding have been reported. Both lower body, trunk and upper body regions could benefit from active exoskeletons. Muscle activity reductions up to 80% have been reported as an effect of active exoskeletons. Exoskeletons have the potential to considerably reduce the underlying factors associated with work-related musculoskeletal injury.

Practitioner Summary:

Worldwide, a significant interest in industrial exoskeletons does exist, but a lack of specific safety standards and several technical issues hinder mainstay practical use of exoskeletons in industry. Specific issues include discomfort (for passive and active exoskeletons), weight of device, alignment with human anatomy and kinematics, and detection of human intention to enable smooth movement (for active exoskeletons).  相似文献   


14.
Conventional information science generally considers an information process, but traditionally uses the probability measure for random events, and Shannon’s entropy measure as an uncertainty function of the states. The cutting process on separated states decreases quantity information concealed in the states correlation, holding hidden process information.

Up to now, “information process” has not had a scientifically conclusive definition nor its implicit structure.

The presenting information process performs logical operations with discrete information units (Bits) to achieve a goal, integrating the discrete mutually connected sequence of symbols and the extracting process’ hidden information in the structure of an information Observer. The probing time-space observation develops the unit of space-time geometry-memorizing logic.

The defined information process starts generating observations of a random process via the logic of probing impulses, sequentially cutting the process entropy measure and creating the discrete information units whose integration enfolds the information geometrical structure of an Observer. Found composite stages of the information process and the synthesized optimal process trajectory minimize observation time in an artificially designed information Observer with intellectual searching logic. The analytical modeling, computer simulations, and experimental applications validate the results.  相似文献   


15.
Postural stability has been shown to be impacted by footwear and task performed. This study analysed the impact of two military footwear, standard boot (STB) and minimalist boot (MTB) on postural stability, before (PRE) and after (POST) a load carriage task. Sixteen participants were tested for postural stability using sensory organisation and motor control tests on Neurocom Equitest?. Postural sway, equilibrium scores and postural latencies were analysed using a two-factor repeated measures ANOVA: boot type (STB-MTB)?×?time (PRE-POST) load carriage task. Significantly greater postural sway variables, lower balance scores and slower postural latencies were seen in STB and POST load carriage conditions (p?<?.05). The results suggest that MTB exhibited greater balance compared to STB in balance conditions that rely on somatosensory feedback and that balance is lowered after a load carriage task. Decrements in postural stability could be attributed to boot design characteristics and muscular exertion due to the load carriage task.

Practitioner Summary: Maintaining optimal postural stability is crucial in military. Impact of military footwear types and load carriage task on postural stability are addressed. Findings provide footwear design and physical exertion implications on postural stability leading to potential interventions that reduce postural stability decrements; thereby, reducing potential falls and fall related injuries.  相似文献   


16.
Purpose: Identify location and intensity of discomfort experienced by healthy participants wearing cervical orthoses.

Method: Convenience sample of 34 healthy participants wore Stro II, Philadelphia, Headmaster, and AspenVista® cervical orthoses for four-hour periods. Participants reported discomfort level (scale 0–6) and location.

Results: Participants reported mean discomfort for all orthoses over the four-hour test between ‘a little discomfort’ and ‘very uncomfortable’ (mean discomfort score = 1.64, SD = 1.50). Seven participants prematurely stopped tests due to pain and six reported maximum discomfort scores. Significant linear increase in discomfort with duration of wear was found for all orthoses. Significantly less discomfort was reported with Stro II than Headmaster and Philadelphia. Age correlated with greater perceived discomfort. Orthoses differed in the location discomfort was experienced.

Conclusion: Existing cervical orthoses cause discomfort influenced by design and duration of wear with orthoses’ design the more significant factor. This work informed the design of a new orthosis and future orthoses developments.

Practitioner Summary: The purpose of this study was to gain greater knowledge about the discomfort caused by wearing of existing neck orthoses in order to inform the design and development of a new neck orthosis. This study gathers empirical data from a surrogate population and concludes that orthosis design is more influential than the duration of wear.  相似文献   


17.
The construction of automatic control and modelling environments has been attempted using shallow reasoning expert systems. The inadequacy of this approach for real-life systems has become apparent, and the need for deeper knowledge—which can only be obtained by extensive simulation—is now acknowledged.

The simulation process, which consists of model building and model selection, followed by the generation and execution of a software simulator, can be partially automated if an Object-Oriented methodology is adopted. In this article, a methodology is presented, which is presently under investigation in the DESiRE (Dynamic Expert Systems in Robotic Experimentation)project

In the modelling phase, a hierarchical, uniform way of describing and manipulating continuous and discrete models is needed, if the highly desirable reusability of submodels is to be achieved. This is only possible if a clear distinction is made between bare models (and information about their intrinsic coupling) and causal simulation experiment-related data.

In the simulation phase, before generating numerical simulation code, a symbolic reduction of the continuous parts of the model is performed, thus eliminating inaccuracy introduced by the untimely application of possibly unstable numerical algorithms.

Finally, from the reduced representation, executable simulator-objects are produced for use in a distributed environment.  相似文献   


18.
At ToSC 2019, Ankele et al. proposed a novel idea for constructing zero-correlation linear distinguishers in a related-tweakey model. This paper further clarifies this principle and gives a search model for zero-correlation distinguishers. As a result, for the first time, the authors construct 15-round and 17-round zero-correlation linear distinguishers for SKINNY-n-2n and SKINNY-n-3n, respectively, which are both two rounds longer than Anekele et al.’s. Based on these distinguishers, the paper presents related-tweakey zero-correlation linear attacks on 22-round SKINNY-n-2n and 26-round SKINNY-n-3n, respectively.  相似文献   

19.
Book reviews     
Computer Software: legal protection in the United Kingdom Henry Carr & Richard Arnold, 1992 London: Sweet & Maxwell, 2nd ed, xv + 312 pp., £45.00 (hardback)

Advanced Information Systems for Lawyers V. Mital & L. Johnson, 1992 London: Chapman & Hall. pp. 306, £35.00

Law of Contract Laurence Koffman & Elizabeth MacDonald, 1992 London: Fourmat Publishing, 430 pp., paperback £22.50

The Electronic Media and the Transformation of Law M. Ethan Katsh, 1991 Oxford: Oxford University Press. £13.95  相似文献   


20.
Book reviews     
Crime and the Computer, Martin Wasik, 1991, Oxford: Clarendon Press. £35.00.

Yearbook of Law, Computers and Technology, Volume 5. K.V. Russell (Ed.), 1991. London: Butterworths. £29.50.

Computers, Artificial Intelligence and the Law. Mervyn E. Bennun (Ed.), 1991. London: Ellis Horwood. xx +132 (including bibliography & index), £26.50

Modelling Legal Argument: reasoning with cases and hypotheticals. Kevin D. Ashley, 1990. Cambridge: MIT Press. 329 pp.  相似文献   


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