scholarly journals Partition Function Estimation: A Quantitative Study

2021 ◽  
Author(s):  
Durgesh Agrawal ◽  
Yash Pote ◽  
Kuldeep S. Meel
Keyword(s):  
Partition Function ◽  
Empirical Study ◽  
Graphical Models ◽  
Probabilistic Reasoning ◽  
Probabilistic Graphical Models ◽  
Function Estimation ◽  
Exciting Line ◽  
Order Of Magnitude ◽  
Magnitude Difference

Probabilistic graphical models have emerged as a powerful modeling tool for several real-world scenarios where one needs to reason under uncertainty. A graphical model's partition function is a central quantity of interest, and its computation is key to several probabilistic reasoning tasks. Given the #P-hardness of computing the partition function, several techniques have been proposed over the years with varying guarantees on the quality of estimates and their runtime behavior. This paper seeks to present a survey of 18 techniques and a rigorous empirical study of their behavior across an extensive set of benchmarks. Our empirical study draws up a surprising observation: exact techniques are as efficient as the approximate ones, and therefore, we conclude with an optimistic view of opportunities for the design of approximate techniques with enhanced scalability. Motivated by the observation of an order of magnitude difference between the Virtual Best Solver and the best performing tool, we envision an exciting line of research focused on the development of portfolio solvers.

TEM Studies and Contact Resistance of Au/Ni/Ti/Ta/n-GaN Ohmic Contacts

2003 ◽  
Vol 764 ◽  
Author(s):  
D.N. Zakharov ◽  
Z. Liliental-Weber ◽  
A. Motayed ◽  
S.N. Mohammad
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
High Resolution Electron Microscopy ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Resolution Electron ◽  
Order Of Magnitude ◽  
Contact Surfaces ◽  
Electron Energy Loss ◽  
Magnitude Difference

AbstractOhmic Ta/Ti/Ni/Au contacts to n-GaN have been studied using high resolution electron microscopy (HREM), energy dispersive X-ray spectrometry (EDX) and electron energy loss spectrometry (EELS). Two different samples were used: A - annealed at 7500C withcontact resistance 5×10-6 Ω cm2 and B-annealed at 7750C with contact resistance 6×10-5 Ω cm2. Both samples revealed extensive in- and out-diffusion between deposited layers with some consumption ofGaNlayerand formation of TixTa1-xN50 (0<x<25) at the GaN interface. Almost an order of magnitude difference in contact resistances can be attributed to structure and chemical bonding of Ti-O layers formed on the contact surfaces.

The Influence of the Established Links between University Courses on the Quality of Teaching

2018 ◽  
Vol 8 (2) ◽  
pp. 35-48
Author(s):  
Jiří Rybička ◽  
Petra Čačková
Keyword(s):  
Higher Education ◽  
Empirical Study ◽  
The Other ◽  
Coherent System ◽  
University Courses ◽  
Quality Of Teaching ◽  
Education Courses ◽  
Initial Knowledge

One of the tools to determine the recommended order of the courses to be taught is to set the prerequisites, that is, the conditions that have to be fulfilled before commencing the study of the course. The recommended sequence of courses is to follow logical links between their logical units, as the basic aim is to provide students with a coherent system according to the Comenius' principle of continuity. Declared continuity may, on the other hand, create organizational complications when passing through the study, as failure to complete one course may result in a whole sequence of forced deviations from the recommended curriculum and ultimately in the extension of the study period. This empirical study deals with the quantitative evaluation of the influence of the level of initial knowledge given by the previous study on the overall results in a certain follow-up course. In this evaluation, data were obtained that may slightly change the approach to determining prerequisites for higher education courses.

scholarly journals What do class comments tell us? An investigation of comment evolution and practices in Pharo Smalltalk

2021 ◽  
Vol 26 (6) ◽  
Author(s):  
Pooja Rani ◽  
Sebastiano Panichella ◽  
Manuel Leuenberger ◽  
Mohammad Ghafari ◽  
Oscar Nierstrasz
Keyword(s):  
Empirical Study ◽  
Programming Languages ◽  
Program Comprehension ◽  
Assessment Tools ◽  
Support Program ◽  
Writing Style ◽  
High Quality ◽  
Types Of Information ◽  
Similar Code

Abstract Context Previous studies have characterized code comments in various programming languages, showing how high quality of code comments is crucial to support program comprehension activities, and to improve the effectiveness of maintenance tasks. However, very few studies have focused on understanding developer practices to write comments. None of them has compared such developer practices to the standard comment guidelines to study the extent to which developers follow the guidelines. Objective Therefore, our goal is to investigate developer commenting practices and compare them to the comment guidelines. Method This paper reports the first empirical study investigating commenting practices in Pharo Smalltalk. First, we analyze class comment evolution over seven Pharo versions. Then, we quantitatively and qualitatively investigate the information types embedded in class comments. Finally, we study the adherence of developer commenting practices to the official class comment template over Pharo versions. Results Our results show that there is a rapid increase in class comments in the initial three Pharo versions, while in subsequent versions developers added comments to both new and old classes, thus maintaining a similar code to comment ratio. We furthermore found three times as many information types in class comments as those suggested by the template. However, the information types suggested by the template tend to be present more often than other types of information. Additionally, we find that a substantial proportion of comments follow the writing style of the template in writing these information types, but they are written and formatted in a non-uniform way. Conclusion The results suggest the need to standardize the commenting guidelines for formatting the text, and to provide headers for the different information types to ensure a consistent style and to identify the information easily. Given the importance of high-quality code comments, we draw numerous implications for developers and researchers to improve the support for comment quality assessment tools.

scholarly journals Effects of Field Processing of Sorghum Grain on Popping Traits

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 839
Author(s):  
Mitchell Kent ◽  
William Rooney
Keyword(s):  
Impact Force ◽  
Grain Sorghum ◽  
Expansion Ratio ◽  
Direct Impact ◽  
Order Of Magnitude ◽  
Rubber Belt ◽  
Sorghum Grain ◽  
Harvest Moisture ◽  
Quality Measurements

Interest in the use of popped sorghum in food products has resulted in a niche market for sorghum hybrids with high popping quality but little work has been done to assess the relative effects of field processing methods of grain on popping quality. This study evaluated the relative effects of harvest moisture and threshing methods on the popping quality of sorghum grain. A grain sorghum hybrid with good popping quality was produced during two different years in Texas wherein it was harvested at two moisture levels (low and high) and grain was removed from panicles using five different threshing methods (hand, rubber belt, metal brushes and two metal concave bar systems). Years, harvest moisture content and threshing method influenced all three popping quality measurements (popping efficacy, expansion ratio and flake size), but threshing method had an order of magnitude larger effect than either moisture level or year. While many of the interactions were significant, they did not influence the general trends observed. As such, the threshing methods with less direct impact force on the grain (hand and rubber belt) had higher popping quality than those samples threshed with greater impact force on the grain (metal-based systems). The popping quality differences between threshing system are likely due to a reduction in kernel integrity caused by the impacts to the kernel that occurred while threshing the grain. The results herein indicate that field processing of the grain, notably threshing method has significant impacts on the popping quality and should be taken into consideration when grain sorghum is harvested for popping purposes.

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