Matrix Completion for Block-wise Missing Information Case in Subsurface Imaging

Author(s):  
Deniz Kumlu
Author(s):  
Neng-Yu Zhang ◽  
Bruce F. McEwen ◽  
Joachim Frank

Reconstructions of asymmetric objects computed by electron tomography are distorted due to the absence of information, usually in an angular range from 60 to 90°, which produces a “missing wedge” in Fourier space. These distortions often interfere with the interpretation of results and thus limit biological ultrastructural information which can be obtained. We have attempted to use the Method of Projections Onto Convex Sets (POCS) for restoring the missing information. In POCS, use is made of the fact that known constraints such as positivity, spatial boundedness or an upper energy bound define convex sets in function space. Enforcement of such constraints takes place by iterating a sequence of function-space projections, starting from the original reconstruction, onto the convex sets, until a function in the intersection of all sets is found. First applications of this technique in the field of electron microscopy have been promising.To test POCS on experimental data, we have artificially reduced the range of an existing projection set of a selectively stained Golgi apparatus from ±60° to ±50°, and computed the reconstruction from the reduced set (51 projections). The specimen was prepared from a bull frog spinal ganglion as described by Lindsey and Ellisman and imaged in the high-voltage electron microscope.


2014 ◽  
Author(s):  
Miao Fan ◽  
Deli Zhao ◽  
Qiang Zhou ◽  
Zhiyuan Liu ◽  
Thomas Fang Zheng ◽  
...  

2016 ◽  
Vol 69 (1) ◽  
pp. 41-51
Author(s):  
Shigeo Okuma ◽  
Tadashi Nakatsuka
Keyword(s):  

2017 ◽  
Vol 32 (4) ◽  
pp. 61-80 ◽  
Author(s):  
Ellen E. Best ◽  
Jennifer Kahle Schafer

ABSTRACT Practitioners routinely note that new staff lack documentation skills, communication skills, and strong Excel skills. Further, new staff report critical-thinking, written and oral communication, teamwork, and project management skills deserve greater emphasis in Master of Accountancy programs. The AICPA's (2014) Model Tax Curriculum suggests that active learning approaches be used to enable students to build communication, critical-thinking, and interpersonal skills. This case uses a realistic corporate tax return preparation experience to address these criticisms by focusing on four main areas: time management, communication, research, and technical skills. The case is divided into two phases. In Phase 1, students review client information, generate requests from the client for missing information, keep a log of hours spent on the project, research ambiguous issues, meet with the project “senior” to obtain guidance, and prepare electronic work papers. In Phase 2, students incorporate feedback from the senior's review of their work papers to make corrections, prepare a corporate tax return, and create a client letter. Student feedback about the project is positive.


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