Parameter Domain Loudness Estimation in Parametric Audio Object Coding

Author(s):  
Jouni Paulus
1997 ◽  
Vol 119 (2) ◽  
pp. 275-283 ◽  
Author(s):  
Takashi Maekawa ◽  
Wonjoon Cho ◽  
Nicholas M. Patrikalakis

Self-intersection of offsets of regular Be´zier surface patches due to local differential geometry and global distance function properties is investigated. The problem of computing starting points for tracing self-intersection curves of offsets is formulated in terms of a system of nonlinear polynomial equations and solved robustly by the interval projected polyhedron algorithm. Trivial solutions are excluded by evaluating the normal bounding pyramids of the surface subpatches mapped from the parameter boxes computed by the polynomial solver with a coarse tolerance. A technique to detect and trace self-intersection curve loops in the parameter domain is also discussed. The method has been successfully tested in tracing complex self-intersection curves of offsets of Be´zier surface patches. Examples illustrate the principal features and robustness characteristics of the method.


2021 ◽  
Author(s):  
J.Y. Feng ◽  
Z.C. Wei ◽  
M.J. Wang ◽  
X.Q. Wang ◽  
M.L. Guo

Abstract U-pass milling is a roughing method that combines the characteristics of flank milling with conventional trochoidal milling. The tool cuts in and out steadily, and the tool–workpiece wrap angle is maintained within a small range. This method can smooth the cutting force and reduce the peak cutting force while avoiding cutting heat accumulation, which can significantly improve the processing efficiency and reduce tool wear. In this study, a tool path model is established for U-pass milling, and the characteristic parameters of the path are defined. Through a comparative test of three-axis groove milling, it is demonstrated that the peak value and average value of the cutting force are reduced by 25% and 60%, respectively. An impeller runner is considered as the processing object, and the milling boundary parameters are pretreated. A tiling micro-arc mapping algorithm is proposed, which maps the three-dimensional boundary to the two-dimensional parameter domain plane with the arc length as the coordinate axis, and the dimensionally reduced tool contact point distribution form is obtained. The geometric domain tool position point and the interference-free tool axis vector are obtained by calculating the bidirectional proportional domain of the runner and the inverse mapping of any vector in the parameter domain. Finally, the calculation results are nested into the automatically programmed tool (APT) encoding form, and the feasibility of the five-axis U-pass milling tool path planning method is verified through a numerical example.


2012 ◽  
Vol 50 (11) ◽  
pp. 1613-1630 ◽  
Author(s):  
Dénes Takács ◽  
Gábor Stépán
Keyword(s):  

GeoJournal ◽  
1990 ◽  
Vol 20 (2) ◽  
Author(s):  
Heiner Benking ◽  
Heiko Schmidt v. Braun

Author(s):  
Sung Soo Hwang ◽  
Sujung Kim ◽  
Seong-Dae Kim ◽  
Sang-Young Park
Keyword(s):  

Author(s):  
Chenhao Hu ◽  
Ruimin Hu ◽  
Xiaochen Wang ◽  
Tingzhao Wu ◽  
Dengshi Li
Keyword(s):  

2017 ◽  
Author(s):  
Daniel Kaiser ◽  
Marius V. Peelen

AbstractTo optimize processing, the human visual system utilizes regularities present in naturalistic visual input. One of these regularities is the relative position of objects in a scene (e.g., a sofa in front of a television), with behavioral research showing that regularly positioned objects are easier to perceive and to remember. Here we use fMRI to test how positional regularities are encoded in the visual system. Participants viewed pairs of objects that formed minimalistic two-object scenes (e.g., a “living room” consisting of a sofa and television) presented in their regularly experienced spatial arrangement or in an irregular arrangement (with interchanged positions). Additionally, single objects were presented centrally and in isolation. Multi-voxel activity patterns evoked by the object pairs were modeled as the average of the response patterns evoked by the two single objects forming the pair. In two experiments, this approximation in object-selective cortex was significantly less accurate for the regularly than the irregularly positioned pairs, indicating integration of individual object representations. More detailed analysis revealed a transition from independent to integrative coding along the posterior-anterior axis of the visual cortex, with the independent component (but not the integrative component) being almost perfectly predicted by object selectivity across the visual hierarchy. These results reveal a transitional stage between individual object and multi-object coding in visual cortex, providing a possible neural correlate of efficient processing of regularly positioned objects in natural scenes.


Author(s):  
Emmanouil Froudarakis ◽  
Uri Cohen ◽  
Maria Diamantaki ◽  
Edgar Y. Walker ◽  
Jacob Reimer ◽  
...  

AbstractDespite variations in appearance we robustly recognize objects. Neuronal populations responding to objects presented under varying conditions form object manifolds and hierarchically organized visual areas are thought to untangle pixel intensities into linearly decodable object representations. However, the associated changes in the geometry of object manifolds along the cortex remain unknown. Using home cage training we showed that mice are capable of invariant object recognition. We simultaneously recorded the responses of thousands of neurons to measure the information about object identity available across the visual cortex and found that lateral visual areas LM, LI and AL carry more linearly decodable object identity information compared to other visual areas. We applied the theory of linear separability of manifolds, and found that the increase in classification capacity is associated with a decrease in the dimension and radius of the object manifold, identifying features of the population code that enable invariant object coding.


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