Semantic Communications with Variable-Length Coding for Extended Reality

Wireless extended reality (XR) has attracted wide attentions as a promising technology to improve users' mobility and quality of experience. However, the ultra-high data rate requirement of wireless XR has hindered its development for many years. To overcome this challenge, we develop a semantic communication framework, where semantically-unimportant information is highly-compressed or discarded in semantic coders, significantly improving the transmission efficiency. Besides, considering the fact that some source content may have less amount of semantic information or have higher tolerance to channel noise, we propose a universal variable-length semantic-channel coding method. In particular, we first use a rate allocation network to estimate the best code length for semantic information and then adjust the coding process accordingly. By adopting some proxy functions, the whole framework is trained in an end-to-end manner. Numerical results show that our semantic system significantly outperforms traditional transmission methods and the proposed variable-length coding scheme is superior to the fixed-length coding methods.Comment: 1. Update the performance of VL-SCC in Fig8. under new rate allocation architecture 2. Give a fair comparison between VL-SCC and SCC in Fig9. 3. fix the typo of LDPC rate (1/3 changed to 2/3) 4. Reduce L=32 to 16, and update the bp

The benefits of emotional stimuli in a virtual reality cognitive and motor rehabilitation task: assessing the impact of positive, negative and neutral stimuli with stroke patients

VR-based methods for stroke rehabilitation have mainly focused on motor rehabilitation, but there is increasing interest towards the integration of cognitive training for providing more ecologically valid solutions. However, more studies are needed, especially in the definition of which type of content should be used in the design of these tools. One possibility is the use of emotional stimuli, which are known to enhance attentional processes. According to the Socio-emotional Selectivity Theory, as people age, this emotional salience arises for positive and neutral, but not for negative stimuli. Conversely, negative stimuli can be better remembered. In this study, we investigated the impact of using emotional stimuli with positive, negative and neutral valence in a VR cognitive and motor attention task. Ten stroke patients participated in a within subjects experiment with four conditions based on the type of stimuli: abstract (control condition), positive, negative and neutral. The main task consisted of finding a target stimulus, shown for only two seconds, among fourteen neutral distractors. Eye movements were recorded with an eye-tracking system to investigate differences between conditions and in search patterns. Subsequently, a recall task took place and the patients had to identify all the target images among a valence-matched number of distractors. Our results corroborate the attention salience effect of positive and neutral stimuli in the VR task performance. Although we found no statistically significant differences between conditions in the recall task, there was a trend for recalling more negative images. This negative advantage comes at the expense of significantly more wrongly identified images/false memories for negative stimuli. Finally, we performed an analysis in which we relate performance scores with well-established cognitive assessment instruments, which supportsG the use of this approach both for assessment and rehabilitation purposes.info:eu-repo/semantics/publishedVersio

User-centred design of smartphone augmented reality in urban tourism context.

Exposure to new and unfamiliar environments is a necessary part of nearly everyone’s life. Effective communication of location-based information through various locationbased service interfaces (LBSIs) became a key concern for cartographers, geographers, human-computer interaction (HCI) and professional designers alike. Much attention is directed towards Augmented Reality (AR) interfaces. Smartphone AR browsers deliver information about physical objects through spatially registered virtual annotations and can function as an interface to (geo)spatial and attribute data. Such applications have considerable potential for tourism. Recently, the number of studies discussing the optimal placement and layout of AR content increased. Results, however, do not scale well to the domain of urban tourism, because: 1) in any urban destination, many objects can be augmented with information; 2) each object can be a source of a substantial amount of information; 3) the incoming video feed is visually heterogeneous and complex; 4) the target user group is in an unfamiliar environment; 5) tourists have different information needs from urban residents. Adopting a User-Centred Design (UCD) approach, the main aim of this research project was to make a theoretical contribution to design knowledge relevant to effective support for (geo)spatial knowledge acquisition in unfamiliar urban environments. The research activities were divided in four (iterative) stages: (1) theoretical, (2) requirements analysis, (3) design and (4) evaluation. After critical analysis of existing literature on design of AR, the theoretical stage involved development of a theoretical user-centred design framework, capturing current knowledge in several relevant disciplines. In the second stage, user requirements gathering was carried out through a field quasi experiment where tourists were asked to use AR browsers in an unfamiliar for them environment. Qualitative and quantitative data were used to identify key relationships, extend the user-centred design framework and generate hypotheses about effective and efficient design. In the third stage, several design alternatives were developed and used to test the hypotheses through a laboratory-based quantitative study with 90 users. The results indicate that information acquisition through AR browsers is more effective and efficient if at least one element within the AR annotation matches the perceived visual characteristics or inferred non-visual attributes of target physical objects. Finally, in order to ensure that all major constructs and relationships are identified, qualitative evaluation of AR annotations was carried out by HCI and GIS domain-expert users in an unfamiliar urban tourism context. The results show that effective information acquisition in urban tourism context will depend on the visual design and delivered content through AR annotations for both visible and non-visible points of interest. All results were later positioned within existing theory in order to develop a final conceptual user-centred design framework that shifts the perspective towards a more thorough understanding of the overall design space for mobile AR interfaces. The dissertation has theoretical, methodological and practical implications. The main theoretical contribution of this thesis is to Information Systems Design Theory. The developed framework provides knowledge regarding the design of mobile AR. It can be used for hypotheses generation and further empirical evaluations of AR interfaces that facilitate knowledge acquisition in different types of environments and for different user groups. From a methodological point of view, the described userbased studies showcase how a UCD approach could be applied to design and evaluation of novel smartphone interfaces within the travel and tourism domain. Within industry the proposed framework could be used as a frame of reference by designers and developers who are not familiar with knowledge acquisition in urban environments and/or mobile AR interfaces

Conformity Through Fear: A Multimodal Critical Discourse Analysis of COVID-19 Information Adverts

The UK Government has produced an array of televised information adverts or ‘campaigns’ to increase public awareness of COVID-19 and promote compliance with its subsequent policy. Research has shown that compliance with public health policy is influenced by fearful visual-verbal campaign messaging strategies, and that emotive representations of ‘risk’ are generally perceived to be more effective than non-emotive discourse. However, how the Government has semiotically constructed and utilised fear within their COVID-19 campaigns to nudge public compliance remains unexplored. Preliminary analysis of seventeen COVID-19 adverts revealed four sequential phases to the Government’s pandemic response: responsibility, management, mitigation, and reflection. An in-depth Multimodal Critical Discourse Analysis of four selected adverts (one screenshot per advert, per phase), revealed that fear was constructed using less conventional meaning potentials in favour of more implicit multimodal semiotic interactions. By portraying a ‘good’ pandemic subject as one who makes ‘moral’ and ‘rational’ decisions to comply with COVID-19 policy, pre-existing societal inequalities which might hinder compliance, particularly for the socioeconomically disadvantaged groups of society, were reduced and problematised. This raises ethical concerns over notions of ‘expertise’ and the ‘rationalising’ of ‘irrational’ lifestyles. Future research should further explore multimodal nudges in public health campaigns to hold producers accountable

An aesthetics of touch: investigating the language of design relating to form

How well can designers communicate qualities of touch? This paper presents evidence that they have some capability to do so, much of which appears to have been learned, but at present make limited use of such language. Interviews with graduate designer-makers suggest that they are aware of and value the importance of touch and materiality in their work, but lack a vocabulary to fully relate to their detailed explanations of other aspects such as their intent or selection of materials. We believe that more attention should be paid to the verbal dialogue that happens in the design process, particularly as other researchers show that even making-based learning also has a strong verbal element to it. However, verbal language alone does not appear to be adequate for a comprehensive language of touch. Graduate designers-makers’ descriptive practices combined non-verbal manipulation within verbal accounts. We thus argue that haptic vocabularies do not simply describe material qualities, but rather are situated competences that physically demonstrate the presence of haptic qualities. Such competencies are more important than groups of verbal vocabularies in isolation. Design support for developing and extending haptic competences must take this wide range of considerations into account to comprehensively improve designers’ capabilities

Improving intention realisation using emotional cues and implementation intentions.

Background: Remembering to act to realise an intention in the future is an important ability that comprises several cognitive processes, known collectively as prospective memory. Prospective memory failures can be costly, and so the effectiveness of strategies to improve prospective memory is an important area of investigation. Aim: To investigate whether ‘if [cue] – then [response]’ plans, known as implementation intentions, are effective at improving prospective memory and whether their effectiveness can be enhanced by the use of emotionally-valenced cues. Method: A systematic review and set of meta-analyses were conducted to consolidate the current knowledge on the effectiveness of emotional cues at improving prospective memory. Two experimental studies were then conducted which utilised implementation intentions in combination with emotional cues to improve prospective memory in a computer-based task (Experiment 1) and a naturalistic hand-washing task (Experiment 2). Results: The results of the meta-analyses confirmed that despite contradictory results, emotional cues can improve prospective memory. However, the benefit is dependent on both the valence of the emotional cues and the timing of the manipulation of the valence of the cues. The results of the two experimental studies were inconclusive as to whether the strategies of emotional cues and implementation intentions are effective together. In the first experiment, emotional cues were effective at improving prospective memory whereas implementation intentions were not, and in the second experiment the opposite pattern was observed. Conclusion: Although the use of emotional cues and implementation intentions were not observed to be effective together in the present research, important moderating variables were identified that improve our knowledge of the parameters of effectiveness of both implementation intentions and emotional cues. Further research is suggested to continue this line of investigation

Third CLIPS Conference Proceedings, volume 2

Expert systems are computer programs which emulate human expertise in well defined problem domains. The C Language Integrated Production System (CLIPS) is an expert system building tool, developed at the Johnson Space Center, which provides a complete environment for the development and delivery of rule and/or object based expert systems. CLIPS was specifically designed to provide a low cost option for developing and deploying expert system applications across a wide range of hardware platforms. The development of CLIPS has helped to improve the ability to deliver expert system technology throughout the public and private sectors for a wide range of applications and diverse computing environments. The Third Conference on CLIPS provided a forum for CLIPS users to present and discuss papers relating to CLIPS applications, uses, and extensions