Recording Technology Research Articles

P‐7.3: Unidirectional Observable Window Signage Using Structural Colors Which Enable to Make Images Invisible from Back Side

It stands to reason that someone observes mirrored imaging according to the direction of viewing if you draw something on the transparent material. The authors dislike this mirrored imaging problem, although it is not a fatal defect. In 2021, our research group proposed window signage using dye‐doped thin film layer to avoid this problem of mirrored imaging. But our 2021 model had a defect that the transparency of a glass window with half mirror layer was less than the general glass material without half mirror because of image generating mechanism. To solve this “reflect surroundings” problem, we needed to find new technology for generating color using a transparent material. This paper shows a unidirectional observable window signage using holographic imaging or holographic optical elements for unidirectional color generating by light controls, how to make structural colors using holographic recording technology and material development.

Heartbeat detector from ECG and PPG signals based on wavelet transform and upper envelopes

The analysis of cardiac activity is one of the most common elements for evaluating the state of a subject, either to control possible health risks, sports performance, stress levels, etc. This activity can be recorded using different techniques, with electrocardiogram and photoplethysmogram being the most common. Both techniques make significantly different waveforms, however the first derivative of the photoplethysmographic data produces a signal structurally similar to the electrocardiogram, so any technique focusing on detecting QRS complexes, and thus heartbeats in electrocardiogram, is potentially applicable to photoplethysmogram. In this paper, we develop a technique based on the wavelet transform and envelopes to detect heartbeats in both electrocardiogram and photoplethysmogram. The wavelet transform is used to enhance QRS complexes with respect to other signal elements, while the envelopes are used as an adaptive threshold to determine their temporal location. We compared our approach with three other techniques using electrocardiogram signals from the Physionet database and photoplethysmographic signals from the DEAP database. Our proposal showed better performances when compared to others. When the electrocardiographic signal was considered, the method had an accuracy greater than 99.94%, a true positive rate of 99.96%, and positive prediction value of 99.76%. When photoplethysmographic signals were investigated, an accuracy greater than 99.27%, a true positive rate of 99.98% and positive prediction value of 99.50% were obtained. These results indicate that our proposal can be adapted better to the recording technology.

A Unified, SNR-Aware SC-LDPC Code Design With Applications to Magnetic Recording

Spatially coupled (SC)-low-density parity-check (LDPC) codes are known to have outstanding error-correction performance and low decoding latency, which make them an excellent choice for high-density magnetic recording (MR) technologies. Whereas previous works on LDPC and SC-LDPC codes mostly take either an asymptotic or a finite-length design approach, we propose a unified framework for jointly optimizing the codes’ thresholds and cycle counts to address both regimes. We focus on circulant-based (CB) SC-LDPC code family as a representative, high-performance exemplar of structured SC-LDPC codes. The framework is based on efficient traversal and pruning of the code search space, building on the fact that the performance of a CB SC-LDPC code depends on some characteristics of the code’s partitioning matrix, which by itself is much smaller than the code’s full parity-check matrix. We then propose an algorithm that traverses all non-equivalent partitioning matrices and outputs a list of codes, each offering an attractive point on the trade-off between asymptotic and finite-length performance. Our simulations show that our framework results in SC-LDPC codes that outperform the state-of-the-art constructions, over both additive white Gaussian noise (AWGN) and partial response (PR) channel models, and that it offers the flexibility to choose low-signal-to-noise ratio (SNR), high-SNR, or in- between SNR region considering system requirements, e.g., that of the MR device.

The development and evaluation of a predictive productivity model in the ambulatory oncology infusion setting.

Accurately describing pharmacy productivity in the ambulatory oncology infusion setting is important to ensure appropriate labor utilization. The purpose of this study was to develop a productivity model utilizing weighted medication complexity and prospective schedule data to determine if predicted productivity corresponds to actual productivity across 6 ambulatory oncology infusion sites. This study was a 2-part analysis. Part 1 was to modify the historic productivity model from dispense code weighting to individual medication complexity weighting. Medication-specific relative value units were determined by analyzing 12 months of historic timestamp data from the electronic health record and gravimetric technology software. The productivity model containing updated relative value units was compared to the historic model to determine if the difference in total calculated full-time equivalents (FTEs) was within 2.0 FTEs. Part 2 applied prospective infusion schedule data to the updated model to determine if predicted productivity corresponded to actual productivity (within 2.0 FTEs) for pharmacy infusion services. The mean difference in total calculated FTEs for infusion during the study period was 2.46 (standard deviation= 1.87) and was within the range of 2.0 FTEs (P= 0.54), indicating that the updated model was not statistically different from the historic model. The mean difference in total calculated FTEs between the predictive and actual productivity model for infusion was 18.28 (standard deviation= 1.00) and was out of the range of 2.0 FTEs (P < 0.001), indicating that predicted productivity was statistically different from the actual productivity. Medication complexity weighting can be used to provide a comprehensive assessment of workload and productivity across pharmacy infusion services. The methodology used to assess predictive productivity should be explored further.

Flexible and smart electronics for single-cell resolved brain–machine interfaces

Brain–machine interfaces (BMIs) offer the potential for the development of communication tools between the brain and external devices. The current BMI technologies for recording and modulation of electric signals from the brain have made significant contributions to areas such as neuroscience, disease diagnosis, and rehabilitation. Next-generation BMIs require long-term stable recording and modulation of electrical signals from statistically significant neuron populations with millisecond single-cell spatiotemporal resolution. However, there are challenges to achieving this stability due to the mechanical and geometrical mismatches between electronics and the brain tissue. In addition, the requirement to achieve cell-type-specific neuromodulation and transmit and process the ever-increasing volume of data on-the-fly necessitates the implementation of smart electronics. In this review, we first summarize the requirements, challenges, and current limitations of BMIs. We then highlight three major approaches to the fabrication of flexible electronics as implantable electronics, aimed at enabling long-term stable and gliosis-free BMIs. The progress of multifunctional electronics for multimodal recording and modulation of cell-type-specific components in the brain is also discussed. Furthermore, we discuss the integration of wireless and closed-loop modulation, and on-chip processing as smart electronic components for BMIs. Finally, we examine the remaining challenges in this field and the future perspectives for how flexible and smart electronics can address these problems and continue to advance the field of BMIs.

Double-layer magnetic recording with multilayer perceptron decoder for single-reader/two-track reading in BPMR systems

To expand an areal density of hard disk drives, bit-patterned magnetic recording (BPMR) using a patterned medium instead of a granular medium as employed in perpendicular magnetic recording is attracting much attention as the next-generation recording technology. To further increase the storage capacity of BPMR, multi-layer magnetic recording can be combined with BPMR. Therefore, this paper considers double-layer magnetic recording with a single-reader/two-track reading technique for the staggered BPMR system, which is performed together with a rate-3/5 modulation code. This paper proposes to utilize a multilayer perceptron decoder to decode and estimate the log-likelihood ratio value of the recorded bit sequence that is obtained from the equalized channel. Simulation results show that at a bit-error rate of 10−4, the proposed system with a double-layer recording medium can achieve an improvement gain of about 1.2 decibel if compared to that with a regular single-layer recording medium, even in the presence of media noise.

Thinking Outside the Black Box: The Legal Status of Emerging Flight Recorder Technologies in Canada

Thinking Outside the Black Box: The Legal Status of Emerging Flight Recorder Technologies in Canada

Practicing Digital Gastroenterology through Phonoenterography Leveraging Artificial Intelligence: Future Perspectives Using Microwave Systems.

Production of bowel sounds, established in the 1900s, has limited application in existing patient-care regimes and diagnostic modalities. We review the physiology of bowel sound production, the developments in recording technologies and the clinical application in various scenarios, to understand the potential of a bowel sound recording and analysis device-the phonoenterogram in future gastroenterological practice. Bowel sound production depends on but is not entirely limited to the type of food consumed, amount of air ingested and the type of intestinal contractions. Recording technologies for extraction and analysis of these include the wavelet-based filtering, autoregressive moving average model, multivariate empirical mode decompression, radial basis function network, two-dimensional positional mapping, neural network model and acoustic biosensor technique. Prior studies evaluate the application of bowel sounds in conditions such as intestinal obstruction, acute appendicitis, large bowel disorders such as inflammatory bowel disease and bowel polyps, ascites, post-operative ileus, sepsis, irritable bowel syndrome, diabetes mellitus, neurodegenerative disorders such as Parkinson's disease and neonatal conditions such as hypertrophic pyloric stenosis. Recording and analysis of bowel sounds using artificial intelligence is crucial for creating an accessible, inexpensive and safe device with a broad range of clinical applications. Microwave-based digital phonoenterography has huge potential for impacting GI practice and patient care.

Development of an Open-source and Lightweight Sensor Recording Software System for Conducting Biomedical Research: Technical Report.

Digital sensing devices have become an increasingly important component of modern biomedical research, as they help provide objective insights into individuals' everyday behavior in terms of changes in motor and nonmotor symptoms. However, there are significant barriers to the adoption of sensor-enhanced biomedical solutions in terms of both technical expertise and associated costs. The currently available solutions neither allow easy integration of custom sensing devices nor offer a practicable methodology in cases of limited resources. This has become particularly relevant, given the need for real-time sensor data that could help lower health care costs by reducing the frequency of clinical assessments performed by specialists and improve access to health assessments (eg, for people living in remote areas or older adults living at home). The objective of this paper is to detail the end-to-end development of a novel sensor recording software system that supports the integration of heterogeneous sensor technologies, runs as an on-demand service on consumer-grade hardware to build sensor systems, and can be easily used to reliably record longitudinal sensor measurements in research settings. The proposed software system is based on a server-client architecture, consisting of multiple self-contained microservices that communicated with each other (eg, the web server transfers data to a database instance) and were implemented as Docker containers. The design of the software is based on state-of-the-art open-source technologies (eg, Node.js or MongoDB), which fulfill nonfunctional requirements and reduce associated costs. A series of programs to facilitate the use of the software were documented. To demonstrate performance, the software was tested in 3 studies (2 gait studies and 1 behavioral study assessing activities of daily living) that ran between 2 and 225 days, with a total of 114 participants. We used descriptive statistics to evaluate longitudinal measurements for reliability, error rates, throughput rates, latency, and usability (with the System Usability Scale [SUS] and the Post-Study System Usability Questionnaire [PSSUQ]). Three qualitative features (event annotation program, sample delay analysis program, and monitoring dashboard) were elaborated and realized as integrated programs. Our quantitative findings demonstrate that the system operates reliably on consumer-grade hardware, even across multiple months (>420 days), providing high throughput (2000 requests per second) with a low latency and error rate (<0.002%). In addition, the results of the usability tests indicate that the system is effective, efficient, and satisfactory to use (mean usability ratings for the SUS and PSSUQ were 89.5 and 1.62, respectively). Overall, this sensor recording software could be leveraged to test sensor devices, as well as to develop and validate algorithms that are able to extract digital measures (eg, gait parameters or actigraphy). The proposed software could help significantly reduce barriers related to sensor-enhanced biomedical research and allow researchers to focus on the research questions at hand rather than on developing recording technologies.

SAGES video acquisition framework-analysis of available OR recording technologies by the SAGES AI task force.

Surgical video recording provides the opportunity to acquire intraoperative data that can subsequently be used for a variety of quality improvement, research, and educational applications. Various recording devices are available for standard operating room camera systems. Some allow for collateral data acquisition including activities of the OR staff, kinematic measurements (motion of surgical instruments), and recording of the endoscopic video streams. Additional analysis through computer vision (CV), which allows software to understand and perform predictive tasks on images, can allow for automatic phase segmentation, instrument tracking, and derivative performance-geared metrics. With this survey, we summarize available surgical video acquisition technologies and associated performance analysis platforms. In an effort promoted by the SAGES Artificial Intelligence Task Force, we surveyed the available video recording technology companies. Of thirteen companies approached, nine were interviewed, each over an hour-long video conference. A standard set of 17 questions was administered. Questions spanned from data acquisition capacity, quality, and synchronization of video with other data, availability of analytic tools, privacy, and access. Most platforms (89%) store video in full-HD (1080p) resolution at a frame rate of 30 fps. Most (67%) of available platforms store data in a Cloud-based databank as opposed to institutional hard drives. CV powered analysis is featured in some platforms: phase segmentation in 44% platforms, out of body blurring or tool tracking in 33%, and suture time in 11%. Kinematic data are provided by 22% and perfusion imaging in one device. Video acquisition platforms on the market allow for in depth performance analysis through manual and automated review. Most of these devices will be integrated in upcoming robotic surgical platforms. Platform analytic supplementation, including CV, may allow for more refined performance analysis to surgeons and trainees. Most current AI features are related to phase segmentation, instrument tracking, and video blurring.

Our Checkered Past

ABSTRACTDespite advocacy of landscape approaches in cultural resource management (CRM) and critiques of the site concept, CRM data collection methods in the western United States continue to focus on individual archaeological sites as units of observation, analysis, and management. The transect-recording unit (TRU) method strikes a balance between conventional site-based recording methods and site-less survey approaches by dividing survey space into a grid of uniformly sized cells for recording all cultural manifestations observed across a survey area. TRU survey generates site boundaries required by CRM regulations while retaining a fine-grained spatial framework for landscape-level research and management. This article discusses the technical requirements of the TRU system and its potential for improving landscape-level research and management. Advances in digital recording technologies and analysis techniques render the method efficient and effective in identifying cultural resource distributions and characteristics otherwise obscured by conventional approaches. The research and management potential of the TRU system is illustrated through identification and interpretation of precontact foot trails in New Mexico's Tularosa Basin. These trails are essentially invisible during pedestrian survey but are readily identifiable as linear patterns using aggregated landscape-scale TRU survey data from multiple survey projects, providing novel insight into precontact routes of movement and exchange.

Soundscape Awareness Intervention Reduced Neuropsychiatric Symptoms in Nursing Home Residents With Dementia: A Cluster-Randomized Trial With MoSART.

Auditory environments as perceived by an individual, also called soundscapes, are often suboptimal for nursing home residents. Poor soundscapes have been associated with neuropsychiatric symptoms (NPS). We evaluated the effect of the Mobile Soundscape Appraisal and Recording Technology sound awareness intervention (MoSART+) on NPS in nursing home residents with dementia. A 15-month, stepped-wedge, cluster-randomized trial. Every 3months, a nursing home switched from care as usual to the use of the intervention. The 3-month MoSART+ intervention involved ambassador training, staff performing sound measurements with the MoSART application, meetings, and implementation of microinterventions. The goal was to raise awareness about soundscapes and their influence on residents. We included 110 residents with dementia in 5 Dutch nursing homes. Exclusion criteria were palliative sedation and deafness. The primary outcome was NPS severity measured with the Neuropsychiatric Inventory-Nursing Home version (NPI-NH) by the resident's primary nurse. Secondary outcomes were quality of life (QUALIDEM), psychotropic drug use (ATC), staff workload (workload questionnaire), and staff job satisfaction (Maastricht Questionnaire of Job Satisfaction). The mean age of the residents (n= 97) at enrollment was 86.5 ± 6.7years, and 76 were female (76.8%). The mean NPI-NH score was 17.5 ± 17.3. One nursing home did not implement the intervention because of staff shortages. Intention-to-treat analysis showed a clinically relevant reduction in NPS between the study groups (-8.0, 95% CI -11.7,-2.6). There was no clear effect on quality of life [odds ratio (OR) 2.8, 95% CI -0.7, 6.3], psychotropic drug use (1.2, 95% CI 0.9, 1.7), staff workload (-0.3, 95% CI -0.3, 0.8), or staff job satisfaction (-0.2, 95% CI -1.2, 0.7). MoSART+ empowered staff to adapt the local soundscape, and the intervention effectively reduced staff-reported levels of NPS in nursing home residents with dementia. Nursing homes should consider implementing interventions to improve the soundscape.

Large inverse spin Hall effect in BiSb topological insulator for 4 Tb/in2 magnetic recording technology

It is technically challenging to shrink the size of a tunneling magnetoresistance reader to below 20 nm for magnetic recording technology beyond 4 Tb/in2 due to its complex film stack. Recently, we proposed a reader architecture based on the inverse spin Hall effect to resolve those challenges, referred below as spin–orbit torque (SOT) reader, whose structure consists of a SOT layer and a ferromagnetic layer. However, the heavy metal-based SOT reader has small output voltage and low signal-to-noise ratio (SNR) due to the limited spin Hall angle θSH (&amp;lt; 1) of heavy metals. In this Letter, we demonstrate the integration of BiSb topological insulator with strong inverse spin Hall effect into the SOT reader that can significantly improve the output voltage and SNR. First, we theoretically calculate the noises in a 20 × 20 nm2 BiSb-based SOT reader to establish the relationships between SNR and θSH at various bias currents. We then demonstrate proof-of-concept BiSb-based SOT readers using CoFe/MgO/BiSb stack, which show large output voltages up to 15 mV at an input current of 9.4 kA/cm2 at room temperature. We project a giant θSH = 61 for BiSb. Our work demonstrates the potential of BiSb for SOT reader beyond 4 Tb/in2 magnetic recording technology.

A Comparative Analysis of Gesture Recording Technologies and Recognition Methods

The dynamic development of computing techniques and communication tools and the improvement of network technology have increased the role of information as the main resource in society. The application of information communication technologies has stimulated the development of intellectual and scientific potential all over the world and has been successfully applied to all fields. Gestures are the only means of communication for hearing and speech impaired people. Automatic recognition of gestures in order to facilitate communication through gestures is an urgent issue from both scientific and practical point of view. This article highlights the static and dynamic gestures. The process of gesture recognition collects data by means of various sensor technologies. The article analyzes the image-based and non-image-based technologies and presents their advantages and disadvantages. It also comparatively analyzes the working principle of existing methods proposed for the gestures identification, explores their advantages and disadvantages and interprets the performance of the software which localizes the hand showing the gesture in the video frame. As a result, it develops a machine learning method based on neural networks for high accuracy identification of gestures. The developed method testing on database open for research shows high performance.

Histological E-data Registration in rodent Brain Spaces.

Recording technologies for rodents have seen huge advances in the last decade, allowing users to sample thousands of neurons simultaneously from multiple brain regions. This has prompted the need for digital tool kits to aid in curating anatomical data, however, existing tools either provide limited functionalities or require users to be proficient in coding to use them. To address this we created HERBS (Histological E-data Registration in rodent Brain Spaces), a comprehensive new tool for rodent users that offers a broad range of functionalities through a user-friendly graphical user interface. Prior to experiments, HERBS can be used to plan coordinates for implanting electrodes, targeting viral injections or tracers. After experiments, users can register recording electrode locations (e.g. Neuropixels and tetrodes), viral expression, or other anatomical features, and visualize the results in 2D or 3D. Additionally, HERBS can delineate labeling from multiple injections across tissue sections and obtain individual cell counts.Regional delineations in HERBS are based either on annotated 3D volumes from the Waxholm Space Atlas of the Sprague Dawley Rat Brain or the Allen Mouse Brain Atlas, though HERBS can work with compatible volume atlases from any species users wish to install. HERBS allows users to scroll through the digital brain atlases and provides custom-angle slice cuts through the volumes, and supports free-transformation of tissue sections to atlas slices. Furthermore, HERBS allows users to reconstruct a 3D brain mesh with tissue from individual animals. HERBS is a multi-platform open-source Python package that is available on PyPI and GitHub, and is compatible with Windows, macOS, and Linux operating systems.

ПУБЛІЧНІ ЗАКЛИКИ ДО ГЕНОЦИДУ: ОСОБЛИВОСТІ НОРМАТИВНОЇ КОНСТРУКЦІЇ В МІЖНАРОДНОМУ КРИМІНАЛЬНОМУ ПРАВІ ТА КРИМІНАЛЬНОМУ ЗАКОНОДАВСТВІ УКРАЇНИ

Background. The purpose of the article is to investigate the objective and subjective characteristics of public calls for genocide as a criminal offense (crime) provided for in Part 2 of Art. 442 of the Criminal Code of Ukraine, and in international criminal law. Methods. To achieve the set goal and defined tasks, the logical-normative method and the system analysis method formed the basis of the research. Results. The article highlights the problem of the ratio of normative compositions of public calls to genocide in the criminal legislation of Ukraine and in international criminal law. Сonclusion. The conclusion was drawn that the existence of national, ethnic, racial and religious groups, as a social value, is the object of criminal protection of public calls for genocide, and, accordingly, the direct object of this crime. It was concluded that public calls for genocide can be made in different forms and by means of any means of information transmission, the main feature of such a call is publicity, that is, expressed before or given to an indefinite number of persons, and not to a set of individualized persons. The conclusion was formulated that, unlike the criminal legislation of Ukraine, in accordance with Art. 3 of the Convention criminalizes not just public calls for genocide, but direct and public calls for genocide. Therefore, in international criminal law, calls for genocide are "not limited" to publicity, but they (calls) must be direct. It has also been investigated that the distribution of material calling for genocide consists in bringing its content to the knowledge of an unspecified number of persons and can exist in various forms (including paper, digital, globally available multi-platform encrypted freemium cloud messengers, on film or any other media built on the technology of recording, processing, transmission, storage and reproduction of textual, visual or audiovisual material) and spread in different ways depending, first of all, on the form of their "existence". Forms of actions regulated in Part 2 of Art. 442 of the Criminal Code of Ukraine, are broader than in international criminal law and do not exclude each other, and in a relevant life situation, the subject can commit two or three acts at once within the limits of one actual criminal offense (crime). The subject of public calls for genocide can be not only a public or well-known person (for example, so-called "opinion makers" or "media faces"), but in general, any person who meets (possess) the characteristics necessary and sufficient for its recognition as the subject of a crime in accordance with criminal legislation. In the national criminal legislation of Ukraine, the presence of the purpose of further committing genocide in the case of public appeals and distribution of materials is not a mandatory element of the composition of the criminal offense provided for in part 2 of Article 442 of the Criminal Code of Ukraine; in international criminal law and the practice of its application, a different approach has been developed: a special goal – the further commission of genocide – is a mandatory characteristic of direct and public calls for genocide.

‘It is the easiest thing to do’: university students’ perspectives on the role of lecture recording in promoting inclusive education in the UK

ABSTRACT The implementation of lecture recording (LR) technology is becoming common practice in higher education (HE). While it is often promoted as a technological solution to inclusion, there is a need for more in-depth research to examine such assumptions. This study was conducted in a research-intensive elite university in the UK, employing semi-structured interviews with 15 students and 10 teaching staff and focusing on students’ voices as an under-represented dimension of LR research. The student participants recognised the usefulness of LR for improving access to learning activities and its limitations in addressing important pedagogical aspects such as student-staff relationships. LR was perceived to be aligned with a reductionist and tokenistic approach to educational provision – a compromise where the desired changes to HE’s exclusionary structure could not happen. The study concludes by highlighting the necessity of respecting students as agents of change to stimulate the critically informed use of technology for inclusive education.

Multilayer perceptron-based detection for a coded two-dimensional magnetic recording

Recently, magnetic recording technology has been on the verge of reaching its recording density limit. Two-dimensional (2-D) magnetic recording (TDMR) is expected to be a candidate for next-generation magnetic recording because it provides powerful 2-D signal processing tools that are seamlessly compatible with the current technology. However, the degradation in signal quality due to 2-D interference when increasing the recording density far beyond the limit is inevitable even advanced signal processing tools cannot thoroughly handle such interference. In this work, we introduce two architectures of the multilayer perceptron (MLP)-based detection capable of producing soft information in the form of a log-likelihood ratio (LLR) for a coded TDMR system. This also enables turbo decoding capability to take place in the system, which further enhances the system performance. Such an architecture has two structures explicitly designed to execute before and during turbo decoding with a low-density parity-check code. In the first architecture, we employ triple MLP-based detection to process three readback sequences individually. For another architecture, it is designed to collectively process three readback sequences using just single MLP-based detection. The results show that both architectures of proposed detections outperform the systems using the conventional detection based on the Viterbi algorithm and single MLP-based detection achieves slightly better performance than triple MLP-based detection despite having much less complexity.

Usability, acceptability and feasibility of a novel technology with visual guidance with video and audio recording during newborn resuscitation: a pilot study

ObjectiveInadequate adherence to resuscitation for non-crying infants will have poor outcome and thus rationalise a need for real-time guidance and quality improvement technology. This study assessed the usability, feasibility and...

Filming as being, images as evidence

When is film taken as evidence of the past and of truths in the world and when does the content become less significant than the practice of making images itself? The meaning of moving images change as the material and cultural logics and technologies of image production and circulation evolve. In legal and journalistic public discourse, recorded images are meant to be empirical evidence that can hold people accountable for their actions. Video camcorders and then mobile phone cameras democratized recording equipment which in many cases revealed abuses of power. But mobile technologies for recording and circulating film—as well as shifting genres for interpreting them—have also reshaped how audiences understand the veracity of what they see and hear. In shifting attention from content to context, cellphone filming becomes about circulation itself. Rather than a means for gathering evidence (epistemic) it is a sign of presence (ontologic). This has implications for legal cases of sex-gender and racial violence when visual evidence, rather than leading to successful prosecutions, creates defensive outrage amongst the powerful.