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Human Perception (human + perception)
Selected AbstractsHuman Perception of Dental Porcelain Translucency Correlated to Spectrophotometric MeasurementsJOURNAL OF PROSTHODONTICS, Issue 3 2010Min-Chieh Liu DDS Abstract Purpose: This study evaluated the relationship between instrumental measurements and subjective visual assessment of differences in dental porcelain translucency. Materials and Methods: Unshaded feldspathic porcelain was used with controlled amounts of tin oxide to create two groups of 12-mm diameter disks with incremental changes in opacity. Contrast ratio (CR = Yb/Yw) was determined with a spectrophotometer, and used as a measure of porcelain translucency (Group A = 0.20 to 0.40; Group B = 0.6,0.8). Within each group, there were 14 specimens with 11 CRs. Three observer groups (first year dental students, residents, faculty with >10 years of shade matching experience) were recruited to assess the translucency between porcelain disks under two lighting conditions (reflected light, transmitted light). Each subject's ability to distinguish between specimens of differing translucency was determined. Descriptive statistics and three-way ANOVA followed by a post-hoc Tukey-Kramer test were used to evaluate the translucency perception threshold (TPT) of subjects (,= 0.05). Results: The overall mean TPT (,C) was 0.07, while 50% of the subjects could perceive a 0.06 CR difference between porcelain specimens. Three-way ANOVA revealed a significant difference in translucency perception among the observer groups (p < 0.0001), whereas the main effects for porcelain opacity (p= 0.3038) and lighting condition (p= 0.0645) were not significant, and no significant interactions were found. Post-hoc Tukey-Kramer test indicated that the mean TPT observed in the faculty group (,C = 0.04) was significantly lower than those observed in student (,C = 0.09) and resident groups (,C = 0.08), while there was no significant difference between students and residents. Conclusions: The overall mean TPT of all subjects was 0.07, and 50% of the study population perceived a 0.06 CR difference in translucency. Increased shade matching experience (,10 years) significantly improved the ability to perceive differences in translucency; however, neither the viewing condition nor porcelain opacity affected the perceived translucency threshold. [source] Human perception of verticality: Psychophysical experiments on the centrifuge and their neuronal implicationsJAPANESE PSYCHOLOGICAL RESEARCH, Issue 4 2000Fred W. Mast The role of the otoliths in the perception of verticality is analyzed in two different gravitational environments, 1 g and 1.5 g, and in different roll body positions between upright and upside down. The subjective visual vertical (SVV) is determined when a subject judges the orientation of an indicator as apparently vertical. An increase of g level hardly affects the SVV in the subject's frontal plane (y-z plane). However, for the first time, a three-dimensionally adjustable indicator was used for the SVV and this revealed a new phenomenon: An increase of g level induces a backward slant of the SVV into subject's median plane (x-z plane). The data are discussed with regard to Mittelstaedt's SVV theory; particular emphasis is given to the otolith-head coordinate transformation and the normalization of afferent otolith components. The results of this study provide evidence that the former is implemented at an earlier level and thus precedes the latter. [source] Choreographing emotional facial expressionsCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2010Robin J.S. Sloan Abstract While much is known about the appearance and human perception of emotional facial expressions, researchers and professionals experience difficulties when attempting to create believable animated characters. Methods for automating or capturing dynamic facial expressions have come on in leaps and bounds in recent years, resulting in increasingly realistic characters. However, accurate replication of naturalistic movement does not necessarily ensure authentic character performance. In this paper, the authors present a project which makes use of creative animation practices and artistic reflection as methods of research. The output of animation practice is tested experimentally by measuring observer perception and comparing the results with artistic observations and predictions. Ultimately, the authors aim to demonstrate that animation practice can generate new knowledge about dynamic character performance, and that arts-based methods can and should be considered valuable tools in a field often dominated by technical methods of research. Copyright © 2010 John Wiley & Sons, Ltd. [source] Perceptual 3D pose distance estimation by boosting relational geometric featuresCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2-3 2009Cheng Chen Abstract Traditional pose similarity functions based on joint coordinates or rotations often do not conform to human perception. We propose a new perceptual pose distance: Relational Geometric Distance that accumulates the differences over a set of features that reflects the geometric relations between different body parts. An extensive relational geometric feature pool that contains a large number of potential features is defined, and the features effective for pose similarity estimation are selected using a set of labeled data by Adaboost. The extensive feature pool guarantees that a wide diversity of features is considered, and the boosting ensures that the selected features are optimized when used jointly. Finally, the selected features form a pose distance function that can be used for novel poses. Experiments show that our method outperforms others in emulating human perception in pose similarity. Our method can also adapt to specific motion types and capture the features that are important for pose similarity of a certain motion type. Copyright © 2009 John Wiley & Sons, Ltd. [source] Perspective-aware cartoon clips synthesisCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008Yueting Zhuang Abstract In this paper we propose an approach, which allows the users to synthesize cartoon clips according to the perspective of the background image. In order to construct the cartoons smoothly, the character's edge distance and motion direction distance are demonstrated to be the factors affecting the human perception in similarity evaluation, and utilized in cartoon clips synthesis. When applying the generated cartoons to the background image, in which the perspective exists, the size of the character is coordinated according to the scaling factor calculated from the vanishing line. The experiment results demonstrate that our approach can synthesize the cartoon clips more smoothly compared with other single frame reusing strategies. The generated cartoons, which are applied to the background image, can be accepted by the human perception well. Copyright © 2008 John Wiley & Sons, Ltd. [source] Rapid Geometric Modeling for Unstructured Construction WorkspacesCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2003Yong-Kwon Cho Most automated and semi-automated construction tasks require real-time information about the local workspace in the form of 3D geometric models. This article describes and demonstrates a new rapid, local area, geometric data extraction and 3D visualization method for unstructured construction workspaces that combines human perception, simple sensors, and descriptive CAD models. The rapid approach will be useful in construction to optimize automated equipment tasks and to significantly improve safety and a remote operator's spatial perception of the workspace. [source] An iris recognition approach through structural pattern analysis methodsEXPERT SYSTEMS, Issue 1 2010Hugo Proença Abstract: Continuous efforts have been made to improve the robustness of iris coding methods since Daugman's pioneering work on iris recognition was published. Iris recognition is at present used in several scenarios (airport check-in, refugee control etc.) with very satisfactory results. However, in order to achieve acceptable error rates several imaging constraints are enforced, which reduce the fluidity of the iris recognition systems. The majority of the published iris recognition methods follow a statistical pattern recognition paradigm and encode the iris texture information through phase, zero-crossing or texture-analysis based methods. In this paper we propose a method that follows the structural (syntactic) pattern recognition paradigm. In addition to the intrinsic advantages of this type of approach (intuitive description and human perception of the system functioning), our experiments show that the proposed method behaves comparably to the statistical approach that constitutes the basis of nearly all deployed systems. [source] Quantitative model of cellulite: three-dimensional skin surface topography, biophysical characterization, and relationship to human perceptionINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2005L. K. Smalls Gynoid lipodystrophy (cellulite) is the irregular, dimpled skin surface of the thighs, abdomen, and buttocks in 85% of post-adolescent women. The distinctive surface morphology is believed to result when subcutaneous adipose tissue protrudes into the lower reticular dermis, thereby creating irregularities at the surface. The biomechanical properties of epidermal and dermal tissue may also influence severity. Cellulite-affected thigh sites were measured in 51 females with varying degrees of cellulite, in 11 non-cellulite controls, and in 10 male controls. A non-contact high-resolution three-dimensional (3D) laser surface scanner was used to quantify the skin surface morphology and determine specific roughness values. The scans were evaluated by experts and na,ve judges (n = 62). Body composition was evaluated via dual-energy X-ray absorptiometry; dermal thickness and the dermal,subcutaneous junction were evaluated via high-resolution 3D ultrasound and surface photography under compression. Biomechanical properties were also measured. The roughness parameters Svm (mean depth of the lowest valleys) and Sdr (ratio between the roughness surface area and the area of the xy plane) were highly correlated to the expert image grades and, therefore, designated as the quantitative measures of cellulite severity. The strength of the correlations among na,ve grades, expert grades, and roughness values confirmed that the data quantitatively evaluate the human perception of cellulite. Cellulite severity was correlated to BMI, thigh circumference, percent thigh fat, architecture of the dermal,subcutaneous border (ultrasound surface area, red-band SD from compressed images), compliance, and stiffness (negative correlation). Cellulite severity was predicted by the percent fat and the area of the dermal,subcutaneous border. The biomechanical properties did not significantly contribute to the prediction. Comparison of the parameters for females and males further suggests that percent thigh fat and surface area roughness deviation are the distinguishing features of cellulite. [source] A projection-based image quality measureINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2-3 2008Jianxin Pang Abstract Objective image quality measure, evaluating the image quality consistently with human perception automatically, could be employed in image and video retrieval. And the measure with high efficiency and low computational complexity plays an important role in numerous image and video processing applications. On the assumption that any image's distortion could be modeled as the difference between the projection-based values (PV) of reference image and the counterpart of distorted image, we propose a new objective quality assessment method based on signal projection for full reference model. The proposed metric is developed by simple parameters to achieve high efficiency and low computational complexity. Experimental results show that the proposed method is well consistent with the subjective quality score. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 94,100, 2008 [source] Evaluation of driver satisfaction of travel information on variable message signs using fuzzy aggregationJOURNAL OF ADVANCED TRANSPORTATION, Issue 1 2008Dongmin Lee Driver satisfaction regarding travel information provided by variable message signs (VMS), which are part of the Nam-Mountain Tunnel ATIS, was evaluated using fuzzy aggregation. Application of fuzzy aggregation to analyze driver satisfaction allows one to represent the variability and complexity of human perception with great fidelity. A fuzzy weighted average using two sets of fuzzy membership functions was applied to evaluate individual satisfactions of delay and travel time information provided. Then, those individual satisfactions were aggregated to estimate the driver group's overall satisfaction. The evaluated overall satisfaction was 0.65 for delay information and 0.63 for travel time information. Through these results, it was found that users of the travel information provided by the VMS in the Nam-Mountain Tunnel ATIS were somewhat satisfied with the service quality. Those overall satisfactions were compared with a conventional weighted average and traffic operational effects to demonstrate the usefulness of the developed fuzzy method. [source] INFLUENCE OF SODIUM TRIPOLYPHOSPHATE (STP) TREATMENT AND COOKING TIME ON COOK LOSSES AND TEXTURAL PROPERTIES OF RED MEATSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2007S. BELGIN ERDOGDU ABSTRACT Sodium tripolyphosphates (STPs) are important functional additives used in meat products. STPs reduce cook losses and improve textural properties, especially by increasing the water-holding capacity of proteins. However, increases in cooking time or temperature enhance meat proteins' denaturation, resulting in a reduced water-holding capacity. The amount of STPs diffused into meats would play an important role for these changes. Therefore, the objectives of this research were to determine the effects of processing conditions (cooking time, STP concentration and dipping time) on cook losses and textural properties of red meats, and to relate these changes with diffused amount of STPs. For this purpose, meats (2 × 2 × 2 cm in size) were dipped in different concentrations of STP solutions (2, 4 and 6%) for 10, 20 and 30 min, and were cooked in boiling water for 5, 10 and 15 min. Cook losses were calculated from weight changes, and textural properties were determined by applying texture profile analysis to data obtained using Texture Analyzer TA-XT2i (Stable Micro Systems, Godalming, Surrey, U.K.). STPs were found to decrease cook losses and hardness values. While an increase in STP concentration increased cohesiveness, increase in cooking time resulted in higher hardness, gumminess, chewiness and cook losses. An increase in dipping times also decreased the cook losses and hardness. The results showed that STP concentration, STP dipping and cooking times had significant effects on the changes of textural properties and cook losses of meats. These results may be used for further meat processing optimization studies if they get correlated with sensory data obtained at the same conditions. PRACTICAL APPLICATIONS Cooking to assure safety of food products leads to changes in sensory attributes. The major changes occurring in meats are shrinkage, toughening of tissues, releasing of meat juice and color due to the effect of thermal treatment on proteins. Based on these, resulting cook losses for economical considerations and changes in textural properties affecting consumer satisfaction are widely recognized. Because the meat processing industry uses sodium tripolyphosphates (STPs) to improve textural properties and to reduce cook losses, the objective of this research was to determine the effects of STPs and cooking time on cook losses and textural properties of red meats. The results showed that STPs and cooking time affected the changes in cook losses and textural properties significantly. In addition to these results, an optimization study for decreasing cook losses while improving textural properties should be conducted where these changes are attributed to be significant for human perception using a sensory panel. [source] Perceptual error and the culture of open disclosure in Australian radiologyJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2006AG Pitman Summary The work of diagnostic radiology consists of the complete detection of all abnormalities in an imaging examination and their accurate diagnosis. Errors in diagnostic radiology comprise perceptual errors, which are a failure of detection, and interpretation errors, which are errors of diagnosis. Perceptual errors are subject to rules of human perception and can be expected in a proportion of observations by any human observer including a trained professional under ideal conditions. Current legal standards of medical negligence make no allowance for perceptual errors, comparing human performance to an ideal standard. Diagnostic radiology in Australia has a culture of open disclosure, where full unbiased evidence from an examination is provided to the patient together with the report. This practice benefits the public by allowing genuine differences of opinion and also by allowing a second chance of correct diagnosis in cases of perceptual error. The culture of open disclosure, which is unique to diagnostic radiology, places radiologists at distinct medicolegal disadvantage compared with other specialties. (i) Perceptual error should be acknowledged as an integral inevitable part of diagnostic radiology; (ii) culture of open disclosure should be encouraged by the profession; and (iii) a pragmatic definition of medical negligence should reflect the imperfect performance of human observers. [source] Temporal detection in human vision: dependence on eccentricityOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2002R. F. Hess Studies of human perception of time-varying luminance often aim to estimate either temporal impulse response shapes or temporal modulation transfer functions (MTFs) of putative temporal processing mechanisms. Previously, temporal masking data have been used to estimate the properties and numbers of these temporal mechanisms in central vision for 1 cycle per degree (cpd) targets [Fredericksen and Hess (1998)]. The same methods have been used to explore how these properties change with stimulus energy [Fredericksen and Hess (1997)] and spatial frequency [Fredericksen and Hess (1999)]. We present here analyses of the properties of temporal mechanisms that detect temporal variations of luminance in peripheral vision. The results indicate that a two-filter model provides the best model for our masking data, but that no multiple filter model provides an acceptable fit across the range of parameters varied in this study. Single-filter modelling shows differences between processing mechanisms at 1 cpd in central vision and those that operate eccentrically. We find evidence that this change is because of differences in relative sensitivities of the mechanisms, and to differences in fundamental mechanism impulse responses. [source] A Theory of Secondary QualitiesPHILOSOPHY AND PHENOMENOLOGICAL RESEARCH, Issue 3 2006Robert PASNAU The secondary qualities are those qualities of objects that bear a certain relation to our sensory powers: roughly, they are those qualities that we can readily detect only through a certain distinctive phenomenal experience. Contrary to what is sometimes supposed, there is nothing about the world itself (independent of our minds) that determines the distinction between primary and secondary qualities. Instead, a theory of the secondary qualities must be grounded in facts about how we conceive of these qualities, and ultimately in facts about human perception. [source] An integrated pneumatic tactile feedback actuator array for robotic surgeryTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 1 2009Miguel L. Franco Abstract Background A pneumatically controlled balloon actuator array has been developed to provide tactile feedback to the fingers during robotic surgery. Methods The actuator and pneumatics were integrated onto a robotic surgical system. Potential interference of the inactive system was evaluated using a timed robotic peg transfer task. System performance was evaluated by measuring human perception of the thumb and index finger. Results No significant difference was found between performance with and without the inactive mounted actuator blocks. Subjects were able to determine inflation location with > 95% accuracy and five discrete inflation levels with both the index finger and thumb with accuracies of 94% and 92%. Temporal tests revealed that an 80 ms temporal separation was sufficient to detect balloon stimuli with high accuracy. Conclusions The mounted balloon actuators successfully transmitted tactile information to the index finger and thumb, while not hindering performance of robotic surgical movements. Copyright © 2008 John Wiley & Sons, Ltd. [source] ENT challenges at the small scaleTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 2 2007C. J. Coulson Abstract Background In this paper we consider two relatively frequently performed operations in the field of ear, nose and throat (ENT) surgery and consider how they could be improved by using robotic applications. We consider currently available robots and propose theoretical robotic solutions. Methods The application of robotic systems for both cochlear implantation and endoscopic sinus surgery was considered. Currently available robotic systems were reviewed and those with potential use in ENT surgery were identified. For aspects of operations where there is no available technology, hypotheses are presented on how robots could help. Results Three robotic systems were identified with potential usage in ENT: the PathfinderÔ neurosurgical robot, the Acrobot® knee replacement system and the autonomous smart drill for drilling a cochleostomy. Conclusions The challenge for the future of ENT is being able to perform tasks beyond the level of human perception and abilities. The examples presented here demonstrate that microtechnologies could be used to reduce complications, decrease operating time and improve clinical results. Copyright © 2007 John Wiley & Sons, Ltd. [source] A multigranular linguistic content-based recommendation modelINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 5 2007Luis Martínez Recommendation systems are a clear example of an e-service that helps the users to find the most suitable products they are looking for, according to their preferences, among a vast quantity of information. These preferences are usually related to human perceptions because the customers express their needs, taste, and so forth to find a suitable product. The perceptions are better modeled by means of linguistic information due to the uncertainty involved in this type of information. In this article, we propose a content-based recommendation model that will offer a more flexible context to improve the final recommendations where the preferences provided by the sources will be modeled by means of linguistic variables assessed in different linguistic term sets. The proposal consists of offering a multigranular linguistic context for expressing the preferences instead of forcing users to use a unique scale. Then the content-based recommendation model will look for the most suitable product(s), comparing them with the customer(s) information according to its resemblance. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 419,434, 2007. [source] African elephants Loxodonta africana and human-elephant interactions: implications for conservationINTERNATIONAL ZOO YEARBOOK, Issue 1 2006P. C. LEE African elephants face an uncertain future. Politics, war, sustained media campaigns, corrupt, weak or absent institutions supporting conservation, land-use planning or general governance, and greed are all bringing elephants into direct conflict with humans. Although elephant populations have declined considerably relative to their historical size and range, human populations have expanded to occupy and intensively use remaining elephant areas. Strategies to minimize perceptions of conflict and the implementation of land-use planning with biodiversity protection as its goal could help to sustain at least some populations of elephants. Here, we review threats to elephants, with an emphasis on those resulting from human perceptions of conflict, and suggest some mechanisms for grappling with these threats. [source] Tropical Storm Gamma and the Mosquitia of eastern Honduras: a little-known story from the 2005 hurricane seasonAREA, Issue 4 2009David M Cochran Jr The 2005 Atlantic hurricane season was unprecedented in terms of storm activity in the United States, Mexico, Central America and Caribbean. Given the impacts of hurricanes Katrina and Rita, the Honduran Mosquitia sparked little attention despite being hit by two hurricanes and a tropical storm in 2005. This article recounts the history of these storms in the Afro-Caribbean community of Batalla, drawing from public weather advisories and testimony of local residents obtained through participatory research. We contextualise this local history with results from the first paleotempestological study undertaken in the Mosquitia to shed light on long-term risk of catastrophic storms in the region and to demonstrate the value of integrating these two research approaches. Our findings contribute to recent ethnographic research on hazards by describing how a coastal people understand and respond to tropical cyclones and how landscape change influences the vulnerability of a coastal area. Although residents have not witnessed a storm as intense as those documented in the paleotempestological record, their knowledge and perceptions show how tropical cyclones can be disasters while leaving behind no sedimentary records. The paleotempestological evidence, however, reminds us that catastrophic hurricanes have struck the Mosquitia in the past and will do so again in the future. Understanding the interactions between contemporary human perceptions and responses and long-term hurricane risk provides insight for emergency managers and local stakeholders to better prepare for such a catastrophic event. [source] | ||||||||||||||||||||||