Indoor 3D localization with low-cost LiFi components

Indoor positioning or localization is an enabling technology expected to have a profound impact on mobile applications. Various modalities of radio frequency, ultrasound, and light can be used for localization; in this paper we consider how visible light positioning can be realized for 3D positioning as a service comprised of optical sources as part of an overarching lighting infrastructure. Our approach, called Ray-Surface Positioning, uses one or more overhead luminaires, modulated as LiFi, and is used in conjunction with a steerable laser to realize position estimates in three dimensions. In this paper, we build and demonstrate Ray-Surface Positioning using low-cost commodity components in a test apparatus representing one quadrant of a 4m × 4m × 1m volume. Data are collected at regular intervals in the test volume representing 3D position estimates and is validated using a motion capture system. For the low-cost components used, results show position estimate errors of less than 30cm for 95% of the test volume. These results, generated with commodity components, show the potential for 3D positioning in the general case. When the plane of the receiver is known a priori, the position estimate error diminishes to the resolution of the steering mechanism.Accepted manuscrip

Subdivided Windows with Mixed Shading Devices: A Daylighting Solution for Effective Integration of Occupants into the Building Environmental Control

Daylighting is one of the most challenging aspects of an ecological building design. The dynamic nature of daylight along with a wide range of individual preferences makes it a complex design issue. The art of daylighting relies on fine-tuning a delicate balance between admitting sufficient daylight for occupant well being and task performance and preventing glare and over heating. These goals are rarely achieved in buildings where fenestration design is reduced to an opening with an interior blind due to occupants\u27 infrequent shade operation. To address this problem, a number of automatic shading devices have been developed to be integrated with the lighting control system for an optimized daylit environment. Although such systems reveal substantial energy savings in laboratory and energy modeling tools, evidence has accumulated that they do not perform well in real buildings and disregard occupants\u27 need for perceived control over their environment. This dissertation aimed at examining the potentials of a subdivided window in solving the current challenges of daylighting side-lit spaces. The field observation suggested that a subdivided window with horizontal shading devices increases occupants\u27 chance of raising the blinds and reduces their lighting energy consumption. The simulation studies established that subdivided windows combining automatic and manual shading devices have the potential to significantly reduce the lighting energy use and maintain a well-daylit environment throughout the year

Neural Precomputed Radiance Transfer

OPAL-MesoInternational audienceRecent advances in neural rendering indicate immense promise for architectures that learn light transport, allowing efficient rendering of global illumination effects once such methods are trained. The training phase of these methods can be seen as a form of pre-computation, which has a long standing history in Computer Graphics. In particular, Pre-computed Radiance Transfer (PRT) achieves real-time rendering by freezing some variables of the scene (geometry, materials) and encoding the distribution of others, allowing interactive rendering at runtime. We adopt the same configuration as PRT – global illumination of static scenes under dynamic environment lighting – and investigate different neural network architectures, inspired by the design principles and theoretical analysis of PRT. We introduce four different architectures, and show that those based on knowledge of light transport models and PRT-inspired principles improve the quality of global illumination predictions at equal training time and network size, without the need for high-end ray-tracing hardware

Literature review - Energy saving potential of user-centered integrated lighting solutions

Measures for the reduction of electric energy loads for lighting have predominantly focussed on increasing the efficiency of lighting systems. This efficiency has now reached levels unthinkable a few decades ago. However, a focus on mere efficiency is physically limiting, and does not necessarily ensure that the anticipated energy savings actually materialize. There are technical and non-technical reasons because of which effective integration of lighting solutions and their controls, and thus a reduction in energy use, does not happen. This literature review aims to assess the energy saving potential of integrated daylight and electric lighting design and controls, especially with respect to user preferences and behaviour. It does so by collecting available scientific knowledge and experience on daylighting, electric lighting, and related control systems, as well as on effective strategies for their integration. Based on this knowledge, the review suggests design processes, innovative design strategies and design solutions which – if implemented appropriately – could improve user comfort, health, well-being and productivity, while saving energy as well as the operation and maintenance of lighting systems. The review highlights also regulatory, technical, and design challenges hindering energy savings. Potential energy savings are reported from the retrieved studies. However, these savings derived from separate studies are dependent on their specific contexts, which lowers the ecological validity of the findings. Studies on strategies based on behavioural interventions, like information, feedback, and social norms, did not report energy saving performance. This is an interesting conclusion, since the papers indicate high potentials that deserve further exploration. Quantifying potential savings is fundamental to fostering large scale adoption of user-driven strategies, since this would allow at least a rough estimation of returns for the investors. However, such quantification requires that studies are designed with an inter-disciplinary approach. The literature also shows that strategies, where there is more communication between façade and lighting designers, are more successful in integrated design, which calls for more communication between stakeholders in future building processes