Shape Estimation Research Articles

Relationship Among Myofiber Shapes, Myofiber Cross-Sectional Area, and Circularity Parameter

<h3>Research Objectives</h3> To clarify the relationship among myofiber shapes, myofiber cross-sectional area, and circularity parameter. <h3>Design</h3> Randomized controlled trial study. <h3>Setting</h3> Department of Physical Therapy, Japan University of Health Sciences. <h3>Participants</h3> 500 myofibers in soleus muscles of 11-week-old male Wistar rats. <h3>Interventions</h3> Soleus muscles of five 11-week-old male Wistar rats were collected as samples. Muscle samples were rapid-frozen in isopentane—cooled in dry ice and acetone—and sliced into 10-μm slices in a cryostat, then stained with hematoxylin–eosin. The NIH-ImageJ software was used to analyze the number of corners that were counted according to the proposed criteria and myofiber cross-sectional area (MFCSA) of 500 myofibers. <h3>Main Outcome Measures</h3> Relationship among the approximate shape of myofiber cross-section (MFCS), myofiber cross-sectional area, and circularity parameter. <h3>Results</h3> As for the approximate shape of MFCS, the proportion of pentagons was 41%, which was the highest among polygons. A weak positive correlation was noted between the corner count and MFCSA, which indicated that polygons with more number of corners were associated with larger MFCSA. <h3>Conclusions</h3> It was suggested that the MFCS of soleus muscle had many approximate shape of pentagons. Moreover, a correlation was observed between MFCS and MFCSA, suggesting that it was also associated with the relevant functional features. <h3>Author(s) Disclosures</h3> The authors declare no conflicts of interest associated with this manuscript.

Indicators of Higher Education and the Public Good in Africa: A Dashboard Approach

Indicators and metrics have gained increasing prominence in international higher education in recent years, and global rankings have become a powerful force in shaping ideas of what the university is and should be. Yet these measures do a poor job of capturing the broad role of the institution, and particularly in recognising its actions in promoting the public good and addressing inequalities. African higher education institutions have struggled to perform well in the conventional rankings, whose indicators rely on extensive resources for high-level research. This article explores the possibilities of alternative metrics for understanding the public good contribution of universities in the context of four African countries: Ghana, Kenya, Nigeria and South Africa. After assessing the shortcomings of the existing indicators and metrics, and the challenges of the availability of data, it puts forward a dashboard approach as a possible new model. Dashboards have the advantage of avoiding the conflation of diverse qualities of importance and allow different profiles of an institution to be compared. The article proposes six main elements for the dashboard: solidarity with society, equitable access and deliberative space (which correspond to the intrinsic notion of public good and graduate destinations, knowledge production and community engagement (which correspond to instrumental notions). Finally, the challenges of implementing public good metrics in practice are discussed.

A Novel Training Quantitative Evaluation Method Based on Virtual Reality

Quantitative training virtualization can be applied in the fields of human–computer interaction, virtual reality and motion analysis, and has attracted much attention. Based on the virtual reality theory, this paper constructs a training quantitative evaluation method, evaluates the trainer’s ergonomics, and finally compares the evaluation method with the simulation results. According to the collected training data, this paper uses the methods of model reuse and feature parameter adjustment in the Jack software to quickly generate a 3D training model with the required percentages, and performs data reorganization and analysis on the captured training data, which solves the problem of training quantitative evaluation and the problem of uncertainty of results. During the simulation process, according to its reorganized data, a large number of comparative experiments and evaluations were performed on the performance of the model proposed in this paper on multiple indicators of multiple public data sets. The experimental results show that the cycle is reduced by 10 times, the mini-batch is 32, and the sequence length is 16. In this way, the spatial characteristics of the channel coupling relationship can be better analyzed, and the effect of spatial cognitive training can be effectively evaluated. The training pose and shape estimation model and the corresponding data set and multiple indicators have reached the performance of the existing state-of-the-art models. The integrated model of accurate training pose and shape sequence in the camera coordinate system can be reconstructed, which effectively enhances the effectiveness of the virtual scene parameter adjustment strategy.

Design optimization and analysis of HTHL suborbital spaceplanes propelled by hybrid rocket motors

In this paper, a design optimization and parameter analysis of a horizontal takeoff horizontal landing (HTHL) suborbital spaceplane propelled by a hybrid rocket motor (HRM) is proposed. Referenced by a prototype, an integrated design model, including the mass and shape estimation, HRM design, aerodynamic calculation, and trajectory simulation, is established. A series of long burning experimental tests in the reference article is adopted to modify the influence of nozzle erosion on HRM. After modification, the results of HRM design are well fitted with the test ones, which verified the precision of the modified model and revealed the importance of erosion effect on HRM performance. Then, the integrated design process is built and optimized by the multi-island genetic algorithm. The results indicated that the designed HRM-propelled suborbital spaceplane could achieve the target flight height under all the constraints. The parameter analysis (PA) based on optimum result is adopted to analyze the influences of design variables on the performance parameters of the HTHL suborbital spaceplane, and it also gives theoretical reference to the design optimization of the similar aerospace vehicles.

Enabling self-shape estimation of composite structures using distributed microfabricated strain gauge networks

In this study, smart multifunctional composites (SMC) were developed to enable state estimation of structures in terms of the deformations at distributed locations due to applied loads and temperature gradients. The SMC was composed of a carbon fiber-reinforced polymer (CFRP) composite plate and an embedded microfabricated sensor network of densely distributed strain gauges. The microfabricated sensor network, with serpentine signal wires connecting the sensing elements, was manufactured on a 100 mm diameter silicon wafer using integrated circuit batch processing techniques. The robustness of the SMC was investigated and verified through shape estimation under mechanical loads and temperature gradients applied to the SMC. The mechanical load was applied to the SMC with fixed boundaries on four edges. The temperature gradient was applied to the SMC with simple supports on the four corners of the SMC plate by applying a uniform temperature on one side while controlling the temperature of the other side close to the room temperature. The results show that the SMC provides the shape of the deformed structure under loads with high resolution. Moreover, a numerical analysis of the SMC implemented in ABAQUS demonstrates a close correlation between the estimated deformed shape and the simulated structure allowing the potential establishment of a digital twin. The SMC can be customized based on different requirements and applications by selecting the type, number, and locations of the sensors. The shape and state of the structure obtained from the SMC during operation can be used for online control, autonomy, decision-making, and maintenance.

A comparative evaluation of snowflake particle shape estimation techniques used by the Precipitation Imaging Package (PIP), Multi-Angle Snowflake Camera (MASC), and Two-Dimensional Video Disdrometer (2DVD)

Abstract. Measurements of snowflake particle shape are important for studying snow microphysics. While a number of instruments exist that are capable of measuring particle shape, this study focuses on the measurement techniques of three digital video disdrometers: the Precipitation Imaging Package (PIP), the Multi-Angle Snowflake Camera (MASC), and the Two-Dimensional Video Disdrometer (2DVD). To gain a better understanding of the relative strengths and weaknesses of these instruments and to provide a foundation upon which comparisons can be made between studies using data from different instruments, we perform a comparative analysis of the shape measurement algorithms employed by each of the three instruments by applying the algorithms to snowflake images captured by PIP during the ICE-POP 2018 field campaign. Our analysis primarily focuses on the measurement of the aspect ratio of either the particle itself, in the case of PIP and MASC, or of the particle bounding box, in the case of PIP and 2DVD. Both PIP and MASC use shape-fitting algorithms to measure aspect ratio. While our analysis of the MASC aspect ratio suggests that the measurements are reliable, our findings indicate that both the ellipse and rectangle aspect ratios produced by PIP underperformed considerably due to the shortcomings of the PIP shape-fitting techniques. We also demonstrate that reliable measurements of aspect ratio can be retrieved from PIP by reprocessing the raw PIP images using either the MASC ellipse-fitting algorithm or a tensor-based ellipse-fitting algorithm. Because of differences in instrument design, 2DVD produces measurements of particle horizontal and vertical extent rather than length and width. Furthermore, the 2DVD measurements of particle horizontal extent can be contaminated by horizontal particle motion. Our findings indicate that, although the correction technique used to remove the horizontal motion contamination performs remarkably well with snowflakes despite being designed for use with raindrops, the 2DVD measurements of particle horizontal extent are less reliable than those measured by PIP.

Stochastic model-based contact force estimation for concentric tube robots

This work utilizes a Wiener process to describe a fluctuating load on a Concentric tube robot (CTR) or its smooth motion through fixed obstacles leading to a kineto-static piecewise constant strain (KPCS) model. We then propose an observer based on the KPCS model, represented as a stochastic switched system, to estimate the externally applied forces by knowing the position of discrete points on the backbone. We have demonstrated that the observer describes the behavior of CTRs in unknown constraint environments and slow movement. The experiments carried out using electromagnetic sensors on the CTR prototype validate the feasibility of the proposed approach for shape and tip-force estimation. The average time required for force estimation is about 3.8, 6.2, and 20 ms per sample, respectively, when the estimated external forces are applied on a three-tube CTR’s tip point and three and fifteen equally spaced points along its length. The implementation results reveal the estimated force reduces the error of the robot tip position by half (about 1.5% of the robot length on average) compared to the known external force.

On mixed finite element approximations of shape gradients in shape optimization with the Navier–Stokes equation

AbstractFor shape optimization of fluid flows governed by the Navier–Stokes equation, we investigate effectiveness of shape gradient algorithms by analyzing convergence and accuracy of mixed finite element approximations to both the distributed and boundary types of shape gradients. We present convergence analysis with a priori error estimates for the two approximate shape gradients. The theoretical analysis shows that the distributed formulation has superconvergence property. Numerical results with comparisons are presented to verify theory and show that the shape gradient algorithm based on the distributed formulation is highly effective and robust for shape optimization.

Rheology dictated spreading regimes of a non-isothermal sessile drop

In the present work, within the framework of thin film theory, we delineate the interaction between the interfacial dynamics of thermal Marangoni flow and non-Newtonian rheology by considering a spreading droplet over a non-isothermal substrate. The numerical simulations, performed at different equilibrium contact angles $(\theta _e)$ , dimensionless thermocapillary strengths $(\beta )$ and shear-dependent viscosities $(n)$ , reveal that the fluid rheology nonlinearly influences the mechanisms of disjoining pressure and Marangoni stress. Accordingly, three distinct spreading regimes for non-Newtonian drops arise. Results indicate that the Marangoni film regime, having an approximate linear drop shape, sustains at lower $\theta _e$ , higher $\beta$ and $n$ ranges. Also, shear-thickening drops display an early onset of thermocapillary time scale and a steeper advancing front, while their shear-thinning counterparts retain a significant curvature for a much longer time. Contrastingly, the droplet regime is identified by fixed shape and uniform speed $(U)$ at higher $\theta _e$ and lower $(\beta$ , $n)$ combinations. Here, an intricate interplay between $\beta$ and $n$ realizes a sharp increase in $U$ for shear thinning compared with its invariance for shear-thickening droplets. The transition regime appears as an intermediate regime between the other two and involves multiple ruptured droplets. In all the regimes, we observe slower (faster) spreading of shear-thinning (thickening) droplets than the Newtonian droplets. In addition, the variations in $n$ cause intense characteristic modulations to spreading attributes like droplet morphology and transient spreading behaviour, and also act as a switching mechanism between different spreading regimes. These unique results may be utilized for superior control of non-isothermal biofluid droplets in microfluidics.

Building the nation on 16mm: Film formats and the institutionalization of cinematic portability in 1930s China

This article examines the role played by the 16 mm format in shaping ideas of portable projection in 1930s China. Drawing on research into the Chinese educational film movement, I argue for a format-oriented approach to cinema history that tracks heretofore neglected aspects of how the state—as well as non-state actors—exercised power on and through cinema. As a portable format, 16 mm extracted cinema from urbanized film culture while offering its users access to a broader ‘national’ audience. Educators built a mobile 16 mm network connecting schools and mass education sites and formulated a discourse that sought to codify the place of ‘small scale cinema’ in the Chinese nation and in global media hierarchies. Small scale cinema was deeply contradictory. While promising to make cinema broadly accessible to the Chinese masses, 16 mm also restricted that access. While seemingly liberating cinema from the sway of global film culture and China’s treaty-port cosmopolitanism, 16 mm subjected mass education to other patterns of asymmetrical development. By examining how educational cinema was formed at the intersection of global film technologies and local institutional discourses, I formulate an approach to cine-governmentality that shows how the state’s control of cinema worked from the bottom up, as actors on multiple scales negotiated chaotic circulations of films, equipment, and ideas.

Soft joint shape measurement device based on FBG with a simple demodulating system.

Soft joint shape measurement is challenging because, in most cases, it relies solely on internal sensors. Existing shape estimation methods commonly take measurements at discrete points and utilize curve-fitting schemes, which are inefficient for complex joint shapes that require continuous measurements. Therefore joint shape measurement sensors rely on the fiber Bragg grating (FBG) due to its sensitivity, immunity to electromagnetic interference, and flexibility. Nevertheless, FBG demodulation is still an open research case. Hence, we propose a shape measurement device appropriate for FBG-based continuous measurements that employs a sensor with only three FBGs thrusting inside the soft joint to measure its 3D shape. Moreover, we develop a simple demodulating system exploiting the FBG's filter overlapping properties and design a calibrating process for FBG signals. Soft joint shape measurement experiments highlight our method's effectiveness, providing a relative error within 0.7%. Further tests involving continuum robot measurement reveal that the achieved precision is of the same level as a motion-capturing system.

Play with a purpose: Intensive parenting, educational desires and shifting notions of childhood and learning in twenty-first century Singapore

This article examines how Singaporean parents negotiate complex expectations in relation to current reforms aimed at raising creative and problem-solving children. Based on ethnographic fieldwork, the article explores how ideas of brain-claiming, resilience, and natural exposure shape parenting practices around young children’s learning. The findings suggest that parents’ sentiments of uncertainty and guilt in relation to their children’s future are entwined with and fueled by a deep-rooted narrative of national survival, reproduced in the form of 21st century skills.

Accelerating convergence in Bayesian operational modal analysis with Fisher information matrix

Bayesian operational modal analysis (BAYOMA) has been increasingly applied to ambient vibration tests, providing a fundamental means for estimating modal properties as well as quantifying their identification uncertainty consistent with probability rules and modelling assumptions. Computing the most probable value of modal parameters in BAYOMA involves a high-dimensional numerical optimisation of the negative log-likelihood function (NLLF). Brute-force optimisation using generic algorithms treating the NLLF as a black box is computationally prohibitive and often non-converging. Efficient iterative algorithms have been developed over the past decade, but challenges still exist, e.g., for very close modes that may require significantly more iterations or (in some cases) may not be converging. Leveraging on recent advance in the mathematics and understanding of the Fisher Information Matrix (FIM) of modal parameters, an efficient method based on Newton-type iterations is proposed in this work to improve computational efficiency and convergence robustness. The MPV estimate in each iteration is updated based on two characteristic types of principal directions of the FIM. Move of the first type involves mode shapes only and is orthogonal to the subspace spanned by the current mode shape estimates. The second type involves updates of all modal parameters, where the mode shapes move within the subspace. Compact analytical expressions are derived for the gradient of NLLF to ensure accurate and efficient use in determining each iteration move. The performance of the proposed method is investigated with a comprehensive study based on synthetic, laboratory and field data. Results reveal that the proposed algorithm generally outperforms existing ones in terms of computational time by an order of magnitude, and it has better convergence robustness especially for challenging cases with very close modes and high modal force coherence.

Full‐field out‐of‐plane vibration displacement acquisition based on speckle‐projection digital image correlation and its application in damage localization

AbstractStereo‐digital image correlation (Stereo‐DIC) has been widely explored for modal analysis in plate‐type structures due to its noncontact and full‐field advantages. However, when the traditional stereo‐DIC is adopted to capture the out‐of‐plane displacements, several challenging issues exist such as the development of surface speckles, asynchronous camera recording, and efficiency and accuracy degradation due to high computation costs. Moreover, with the captured out‐of‐plane displacements, effective and efficient evaluation of the high spatial resolution mode shapes and their application to damage localization are also critical problems. To tackle these issues, a speckle‐projection DIC technique using a single high‐speed camera is proposed to obtain the out‐of‐plane vibration displacements. Moreover, an enhanced peak‐picking modal analysis method is adopted to enhance the estimation accuracy and efficiency of mode shapes. In addition, the low‐rank property of mode shapes in an intact state and the spatial sparse property of damage locations are harnessed for the detection of damage positions without requiring reference data on the healthy state. Finally, the modal analysis and damage localization results based on the proposed speckle‐projection DIC are compared with those of the traditional two‐camera stereo‐DIC technique to verify its feasibility and effectiveness. It is found that the differences in the identified resonant frequencies between these two methods are smaller than 1% for higher modes. Moreover, the proposed speckle‐projection DIC has the same accuracy as the traditional two‐camera stereo‐DIC in terms of measurement accuracy, mode shape estimation, and damage localization.

Applicability and Limitations of Ru’s Formulation for Vibration Modelling of Double-Walled Carbon Nanotubes

In this paper, a comparison is conducted between two different formulations of the van der Waals interaction coefficient between layers, as applied to the vibrations of double-walled carbon nanotubes (DWCNTs); specifically, the evaluation of the natural frequencies is achieved through Ru’s and He’s formulations. The actual discrete DWCNT is modelled by means of a couple of concentric equivalent continuous thin cylindrical shells, where Donnell shell theory is adopted to obtain strain-displacement relationships. In order to take into account the chirality effect of DWCNT, an anisotropic elastic shell model is considered. Simply supported boundary conditions are imposed and the Rayleigh–Ritz method is used to obtain approximate natural frequencies and mode shapes. A parametric analysis considering different values of diameters and numbers of waves along longitudinal and circumferential directions is performed by adopting Ru’s and He’s formulations. From the comparisons, it is evident that Ru’s formulation provides unsatisfactory results for relatively low values of diameters and relatively high numbers of circumferential waves with respect to the more accurate He’s formulation. This behaviour is observed for every number of longitudinal half-waves. Therefore, Ru’s formulation cannot be used for the vibration modelling of DWCNTs in a large range of diameters and wavenumbers.

Review: Mahjong: A Chinese Game and the Making of Modern American Culture, by Annelise Heinz

According to Annelise Heinz, mahjong became a “quintessentially American game” in the twentieth century (p. 3). This is a bold claim and I would wager that many Chinese and Chinese Americans may disagree or, if not, be quite surprised. Nevertheless, Heinz’s study of mahjong in the United States is bold, ambitious, and stunningly detailed. The book is itself the archive of mahjong: a collection of information from newspapers, photographs, diaries, sociological writings, paintings, and many interviews with players, teachers, and marketers. Drawing together a picture of mahjong consumerism and production in China and the United States, most fascinating is Heinz’s study of the mahjong players: Chinese, Chinese American, and Japanese American communities, white Western expats in Shanghai, and Jewish mothers in the United States.Heinz asks a big question: How did mahjong as a game reflect what it meant to be and become “modern”? Heinz’s study contributes to and complicates studies of cultural appropriation and leisure histories. Heinz never uses the phrase cultural appropriation in her book; doing so would be reductive. Instead, Heinz methodically describes the entwined transpacific history of the game, its many different players (Chinese, white women, Jewish American mothers, Airforce wives, Japanese Americans, and Chinese Americans), and its production, marketing, and consumerism in China and the United States, the game’s cultural evolutions, its cross-over appeal, and importantly, the significance that the game had on the formations of race, gender, ethnicity, and national belonging. As Heinz argues, “The history of how mahjong ‘became American’ is also a story of particular communities ‘becoming American’ in the twentieth century” (p. 6).Mahjong helped to redefine and negotiate identities and communities of race, gender, and culture, and in doing so helped shape ideas around what it meant to be modern Americans during different eras. During the 1920s, elite white women donned Chinese costumes, served Asian treats, and played mahjong. Chinese Americans advertised their play of mahjong and used this opportunity to uplift their image in U.S. culture. For second generation Chinese Americans, playing mahjong gave them access to a culture and an identity that was specifically Chinese but also American. Japanese Americans also played mahjong while interned in the Japanese American concentration camps during World War II. There is even a brief mention of elite Black women during the Jazz Age who played mahjong—for these women, the pastime demonstrated their upward mobility as they were able to engage in a game also played by elite white women. During the postwar period, as Jewish Americans became socially and culturally mobile, mahjong play, particularly organized by Jewish American mothers and wives in the suburbs, negotiated gender and class identity as well as their Jewishness and Americanness within a history of U.S. anti-Semitism.You may or may not have a personal interest in mahjong the game; nonetheless, mahjong is both the star and the setting of a compelling study of American modernity during the twentieth century.

Boundary element model for the analysis of the dynamic response of the Soria arch dam and experimental validation from ambient vibration tests

This paper presents a 3D boundary element time–harmonic model for the analysis of the dynamic behavior, under low-level vibrations, of the Soria arch dam (Gran Canaria, Spain). The model takes into account dynamic Soil–Structure Interaction (DSSI), Fluid–Structure Interaction (FSI) and the actual geometry of dam wall and reservoir. The rock and the dam wall are considered as viscoelastic regions, and the water in the reservoir is modeled as an inviscid fluid. The influence of DSSI, FSI, height of the water in the reservoir, accuracy of the geometric modeling of the canyon, and type of transmitting boundary conditions at the truncated end of the reservoir, are evaluated. DSSI and FSI have a significant influence on the dynamic response of the dam, and the accurate representation of the geometry of the canyon is relevant for the correct estimation of the modal shapes. Ambient vibrations tests were also performed, from which the first and third modes could be clearly identified. The comparison between the experimental and numerical natural frequencies and mode shapes suggests that the proposed complete numerical model is able to capture the dynamic response and can be used for the structural health monitoring of the wall of this dam.

Radar Retrieval Evaluation and Investigation of Dendritic Growth Layer Polarimetric Signatures in a Winter Storm

Abstract This study evaluates ice particle size distribution and aspect ratio φ Multi-Radar Multi-Sensor (MRMS) dual-polarization radar retrievals through a direct comparison with two legs of observational aircraft data obtained during a winter storm case from the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) campaign. In situ cloud probes, satellite, and MRMS observations illustrate that the often-observed Kdp and ZDR enhancement regions in the dendritic growth layer can either indicate a local number concentration increase of dry ice particles or the presence of ice particles mixed with a significant number of supercooled liquid droplets. Relative to in situ measurements, MRMS retrievals on average underestimated mean volume diameters by 50% and overestimated number concentrations by over 100%. IWC retrievals using ZDR and Kdp within the dendritic growth layer were minimally biased relative to in situ calculations where retrievals yielded −2% median relative error for the entire aircraft leg. Incorporating φ retrievals decreased both the magnitude and spread of polarimetric retrievals below the dendritic growth layer. While φ radar retrievals suggest that observed dendritic growth layer particles were nonspherical (0.1 ≤ φ ≤ 0.2), in situ projected aspect ratios, idealized numerical simulations, and habit classifications from cloud probe images suggest that the population mean φ was generally much higher. Coordinated aircraft radar reflectivity with in situ observations suggests that the MRMS systematically underestimated reflectivity and could not resolve local peaks in mean volume diameter sizes. These results highlight the need to consider particle assumptions and radar limitations when performing retrievals. significance statement Developing snow is often detectable using weather radars. Meteorologists combine these radar measurements with mathematical equations to study how snow forms in order to determine how much snow will fall. This study evaluates current methods for estimating the total number and mass, sizes, and shapes of snowflakes from radar using images of individual snowflakes taken during two aircraft legs. Radar estimates of snowflake properties were most consistent with aircraft data inside regions with prominent radar signatures. However, radar estimates of snowflake shapes were not consistent with observed shapes estimated from the snowflake images. Although additional research is needed, these results bolster understanding of snow-growth physics and uncertainties between radar measurements and snow production that can improve future snowfall forecasting.

Design, Sensing, and Control of a Magnetic Compliant Continuum Manipulator

Continuum manipulators coupled with magnetic actuation have great potential as steerable instruments for diverse surgical applications. They can be maneuvered inside the human body to reach difficult-to-access surgical sites with contactless actuation. This paper presents a new design of a compliant continuum manipulator of diameter 3 mm and length 70 mm, capable of spatial bending under magnetic actuation. A quasi-static model is developed to estimate the 3D motion of the manipulator. Experiments report an overall mean error in whole shape estimation of the manipulator between the model and the ground truth of 1.7 mm and 4.8 mm, when suspended vertically and horizontally from its base, respectively. Furthermore, fiber Bragg grating (FBG) sensors are integrated with the manipulator to enable shape sensing. Closed-loop control is demonstrated to trace different trajectories with the tip of the manipulator. A square trajectory and a straight line trajectory are generated with an average error in tip position of 4.1 mm between the desired and estimated positions. The potential of the manipulator as a steerable instrument is validated by maneuvering it inside phantoms of a bifurcating arterial system and a heart with visual guidance from a miniature camera.

The ‘Madrasien’: on the trail of a terminology in Indian prehistory

ABSTRACTArchaeological nomenclature influences the classification of cultural phases, objects and related behavioural interpretations. The term ‘Madrasien’, synonymous with the Acheulian, was a key concept in early studies of Indian prehistory, encompassing notions of geographical/administrative boundaries, tool types, cultural identities and migrations. Madrasien was coined in 1931 by the Austrian prehistorian Oswald Menghin and established in South Asian prehistory by V.D. Krishnaswami. Here, the authors trace the evolution of the term, situating it within the wider discourses in Indian prehistory and examining its role in shaping ideas on South Asian Palaeolithic nomenclatures. The Madrasien was gradually replaced by the current medley of African, European and Southeast Asian terminologies.