AN OPTIMAL TRACKING CONTROL APPROACH TO THE SUSTAINED ACCELERATION CONSTRUCTION IN A FLIGHT SIMULATOR MOTION SYSTEM

The purpose of this research is to solve some problems with the optimal control approach to the design of moving flight simulators. A tracking model of the optimal washout filter is applied in the human vestibular sensation system. It can efficiently limit the translational motion of the platform and also generate sustained acceleration. The simulation results demonstrate that we can minimize the difference between the physiological outputs of the vestibular organs of the actual system and the simulator platform system. In this work, the otolith senses not only the high frequency component of the acceleration, but also the sustained acceleration constructed by the gravity component with the corresponding rate‐ limited tilt angle in the simulator. For the tracking model, the actual acceleration input signal is divided into two parts: one is the high frequency component of the acceleration, and the other is the sustained acceleration. Using the tracking methodology, we achieve a high fidelity motion cueing, which shows that the sensing error of the otolith and semicircular canal can be suppressed to below one threshold unit, and that the displacement can also be controlled within the working space of the simulator. Since an actual (generally below 0.8g) simulator can not produce over 1g of sustained acceleration for a high maneuver aircraft, an f‐scale is used to adjust the degree of the simulation limitation.     

2D sound source position estimation using microphone arrays and its application to a VR-based bird song analysis system

ABSTRACT

This paper addresses the problem of 2D sound source localization using multiple microphone arrays in an outdoor environment. Two main issues exist in such localization. Since the localization performance depends on a variety of parameters, the lack of knowledge about how to design the system is one of those issues. A thorough analysis in respect to the accuracy of the localization results with different simulation conditions has been performed. Obtained characteristics lead to a discussion on limitations and applicability of the system. The distinction between multiple simultaneous sound sources is another problem. This is directly related to the appearance of outliers in the localization process. To solve this issue, an outlier removal method is proposed, which takes the properties of the observed sounds into consideration. In this paper a VR-based visualization method of the obtained results is also introduced. As the application scenario, we selected bird song analysis, which provides a challenging environment in terms of constantly changing signal-to-noise ratio and relative sensor-to-target position. A prototype system has been established using the proposed method. Several simulation results have been presented followed by a discussion on the issues. This leads to establishing system design guidelines that ensure a predictable performance.     

基于过零点双耳时间差的运动声源定位

人耳听觉定位的一个主要因素是ITD。在传统的计算声场景分析方法中,对ITD的估计采用对双耳神经发放率做互相关求得。但该方法具有计算量大和抗噪声能力弱两大缺陷,给实现运动声源实时定位带来了巨大瓶颈。对较新的过零时间差（ZCTD）方法进行了改进,采用Teager能量算子（TEO）提取语音包络截取可靠语音段估计ITD,避免了ZCTD方法中用信噪比的估值提取可靠ITD的繁琐步骤,能够更快速、准确地估计ITD,具有较强的抗噪声能力。将该方法运用到运动声源定位上,提出了基于过零点双耳时间差的运动声源定位模型,通过仿真实验验证了其实现运动声源实时定位的可行性。     

语音增强用于抗噪声的汉语说话人识别

大多数实际应用环境中总是存在各种各样的噪声，由于训练环境与识别环境不匹配，现有的绝大多数说话人识别系统在噪声环境中的性能都不可避免的急剧下降。为了让说话人识别系统在强噪声环境中，有较好的识别效果．研究一个将语音增强器和说话人识别系统级连起来的系统，该系统中将语音增强作为前端处理来提高输入的信噪比。实验证明，该系统具有很好的抗噪声性能。     

The use of force feedback and auditory cues for performance of an assembly task in an immersive virtual environment

Using an immersive virtual environment, this study investigated whether the inclusion of force feedback or auditory cues improved manipulation performance and subjective reports of usability for an assembly task. Twenty-four volunteers (12 males and 12 females) were required to assemble and then disassemble five interconnecting virtual parts with either auditory, force, or no feedback cues provided. Performance for the assembly task was measured using completion time and number of collisions between parts, while the users preferences across conditions were evaluated using subjective reports of usability. The results indicated that the addition of force feedback slowed completion time and led to more collisions between parts for males. In contrast, females exhibited no change in the mean completion time for the assembly task but did show an increase in collision counts. Despite these negative performance findings when adding force feedback, users did report perceived increases in realism, helpfulness and utility towards the assembly task when force feedback was provided. Unlike force feedback, the results showed that auditory feedback, indicating that parts had collided during the assembly task, had no negative performance effects on the objective measures while still increasing perceived realism and overall user satisfaction. When auditory cues and force feedback were presented together, performance times, number of collisions, and usability were not improved compared to conditions containing just auditory cues or force feedback alone. Based on these results, and given the task and display devices used in the present study, the less costly option of excluding auditory and force feedback cues would produce the best performance when measured by the number of collisions and completion time. However, if increased ratings of usability for an assembly task are desired while maintaining objective performance levels and reduced cost, then the inclusion of auditory feedback cues is best.     

Some methodological deficiencies in studies on traffic accident predictors

The paper discusses some methodological problems in (psychological) research on traffic accident predictors and reviews a convenience sample of the literature. Three methodological aspects are identified as being important: reliability of accident predictors, time period for accidents used as dependent variable, and culpability for accidents. Papers are scrutinized and most are found to be wanting in these aspects. Traffic researchers do not adhere to, or hardly even discuss, these basic methodological problems. It is concluded that the current research into (psychological) accident predictors is fraught with methodological deficiencies. Why most studies seem to be deficient in these aspects is not clear, as several researchers have pointed out these problems.     

A Neural Model for Context-dependent Sequence Learning

A novel neural network model is described that implements context-dependent learning of complex sequences. The model utilises leaky integrate-and-fire neurons to extract timing information from its input and modifies its weights using a learning rule with synaptic noise. Learning and recall phases are seamlessly integrated so that the network can gradually shift from learning to predicting its input. Experimental results using data from the real-world problem domain demonstrate that the use of context has three important benefits: (a) it prevents catastrophic interference during learning of multiple overlapping sequences, (b) it enables the completion of sequences from missing or noisy patterns, and (c) it provides a mechanism to selectively explore the space of learned sequences during free recall.     

Influence of multisensory feedback on haptic accessibility tasks

Environments of a certain nature, such as those related to maintenance tasks can benefited from haptic stimuli by performing accessibility simulation in a realistic manner. Accessibility is defined as the physical feasibility of accessing an element of a 3D model avoiding undesirable collisions. This paper studies the benefits that multisensory systems can provide in performing this kind of tasks. The research is specially focused on the improvements provided by auditory feedback to the user’s performance. We have carried out a user study where participants had to perform an accessibility task with the aid of different combinations of sensorial stimuli. A large haptic interface for aeronautic maintainability has been extended with real-time sound generation capabilities to study this issue. The results of these experiments show that auditory stimuli provide with useful cues to the users helping them to correct trajectories and hence improving their performance.     

Embodied thermal environments: an examination of older-people's sensory experiences in a variety of residential types

Thermal sensations of space, namely temperature, humidity and the movement of air, can be difficult to separate from other sensory information such as the sound of fans or ventilation equipment, or the smell of damp or cool fresh air. Despite this factor, efforts to reduce the consumption of energy through the installation of low-carbon technologies including sealed whole-building systems frequently isolate the thermal environment and fail to recognise and respond to the influence of other sensory information on personal preferences and behaviours. Older people represent an increasing proportion of the UK's population, can be faced with a range of physiological challenges associated with ageing, and sometimes have long-established personal preferences. Drawing from data collected across the Conditioning Demand Project, this paper explores the embodied nature of older people's experiences of low-carbon and more traditional thermal technologies in private residences, extra-care housing and residential care-homes, focussing specifically upon auditory and olfactory stimulus. Exploring the management of the sensory experience across these settings, we analyse each case to inform the development of new design and policy approaches to tackling housing for older people. In doing so, we further build connections between energy research and debates around sensory urbanism.     

Auditory detection and localization of approaching vehicles

Pedestrians must use a variety of cues when making safe decisions, many of which require processing of auditory information. We examined detection and localization of approaching vehicles using auditory cues. 50 adults ages 18–49 were presented with actual sounds of vehicles approaching at 5, 12, 25, and 35 mph. Three indices were of interest: the distance at which vehicles were detected, participants’ decision regarding the direction from which vehicles were approaching, and their determination of the vehicles’ arrival at their location. Participants more easily detected vehicles moving at higher speeds and vehicles approaching from the right. Determination of the direction of approach reached 90% accuracy or better when vehicles were traveling at, or greater than, 12 mph, and were more approaching from the right. Determination of vehicle arrival deteriorated significantly as speeds increased. Implications of the use of auditory cues in pedestrian settings, and future directions, are discussed.