scholarly journals On Invariant Subspaces in the Lai–Massey Scheme and a Primitivity Reduction

2021 ◽  
Vol 18 (4) ◽  
Author(s):  
Riccardo Aragona ◽  
Roberto Civino
Keyword(s):  
General Result ◽  
Open Problem ◽  
Block Cipher ◽  
Computational Cost ◽  
Invariant Subspaces ◽  
Building Blocks ◽  
Symmetric Cryptography ◽  
The Past ◽  
Feistel Networks ◽  
Subspace Search

AbstractIn symmetric cryptography, the round functions used as building blocks for iterated block ciphers are obtained as the composition of different layers acting as a sequence of bijective transformations providing global increasing complexity. The study of the conditions on such layers which make the group generated by the round functions of a block cipher a primitive group has been addressed in the past years, both in the case of Substitution Permutation Networks and Feistel Networks, giving to block cipher designers the recipe to avoid the imprimitivity attack, which exploits the invariance of some subspaces during the encryption. In the case of Lai–Massey schemes, where both Substitution Permutation Network and Feistel Network features are combined, the resistance against imprimitivity attacks has been a long-standing open problem. In this paper we consider a generalization of such a scheme and we prove its resistance against the imprimitivity attack. Our solution is obtained as a consequence of a more general result in which the problem of proving the primitivity of a generalized Lai–Massey scheme is reduced to the simpler one of proving the primitivity of the group generated by the round functions of a strictly related Substitution Permutation Network. We prove how this implies a reduction in the computational cost of invariant-subspace search.

Formation of Carbon-Oxygen Bond Mediated by Hypervalent Iodine Reagents Under Metal-free Conditions

2020 ◽  
Vol 17 ◽  
Author(s):  
Ayesha Jalil ◽  
Yaxin O Yang ◽  
Zhendong Chen ◽  
Rongxuan Jia ◽  
Tianhao Bi ◽  
...  
Keyword(s):  
Natural Products ◽  
Bond Formation ◽  
Building Blocks ◽  
Review Article ◽  
Hypervalent Iodine ◽  
Metal Free ◽  
Bioactive Natural Products ◽  
The Past ◽  
Oxygen Bond ◽  
Privileged Scaffolds

: Hypervalent iodine reagents are a class of non-metallic oxidants have been widely used in the construction of several sorts of bond formations. This surging interest in hypervalent iodine reagents is essentially due to their very useful oxidizing properties, combined with their benign environmental character and commercial availability from the past few decades ago. Furthermore, these hypervalent iodine reagents have been used in the construction of many significant building blocks and privileged scaffolds of bioactive natural products. The purpose of writing this review article is to explore all the transformations in which carbon-oxygen bond formation occurred by using hypervalent iodine reagents under metal-free conditions

scholarly journals PyroMEMS as Future Technological Building Blocks for Advanced Microenergetic Systems

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 118
Author(s):  
Jean-Laurent Pouchairet ◽  
Carole Rossi
Keyword(s):  
Building Block ◽  
Building Blocks ◽  
Small Scale ◽  
Technological Evolution ◽  
Research Groups ◽  
Function Block ◽  
The Past ◽  
New Methods ◽  
Safety And Reliability ◽  
Electronically Controllable

For the past two decades, many research groups have investigated new methods for reducing the size and cost of safe and arm-fire systems, while also improving their safety and reliability, through batch processing. Simultaneously, micro- and nanotechnology advancements regarding nanothermite materials have enabled the production of a key technological building block: pyrotechnical microsystems (pyroMEMS). This building block simply consists of microscale electric initiators with a thin thermite layer as the ignition charge. This microscale to millimeter-scale addressable pyroMEMS enables the integration of intelligence into centimeter-scale pyrotechnical systems. To illustrate this technological evolution, we hereby present the development of a smart infrared (IR) electronically controllable flare consisting of three distinct components: (1) a controllable pyrotechnical ejection block comprising three independently addressable small-scale propellers, all integrated into a one-piece molded and interconnected device, (2) a terminal function block comprising a structured IR pyrotechnical loaf coupled with a microinitiation stage integrating low-energy addressable pyroMEMS, and (3) a connected, autonomous, STANAG 4187 compliant, electronic sensor arming and firing block.

3D RECONSTRUCTION OF BREAST CANCER FROM MAMMOGRAMS USING VOLUME RENDERING TECHNIQUES

2015 ◽  
Vol 75 (2) ◽  
Author(s):  
Ho Wei Yong ◽  
Abdullah Bade ◽  
Rajesh Kumar Muniandy
Keyword(s):  
Breast Cancer ◽  
3D Reconstruction ◽  
Computational Cost ◽  
Reconstruction Method ◽  
Cancer Model ◽  
Volume Reconstruction ◽  
The Past ◽  
Breast Cancer Model ◽  
Reconstruction Software ◽  
To Come

Over the past thirty years, a number of researchers have investigated on 3D organ reconstruction from medical images and there are a few 3D reconstruction software available on the market. However, not many researcheshave focused on3D reconstruction of breast cancer’s tumours. Due to the method complexity, most 3D breast cancer’s tumours reconstruction were done based on MRI slices dataeven though mammogram is the current clinical practice for breast cancer screening. Therefore, this research will investigate the process of creating a method that will be able to reconstruct 3D breast cancer’s tumours from mammograms effectively.  Several steps were proposed for this research which includes data acquisition, volume reconstruction, andvolume rendering. The expected output from this research is the 3D breast cancer’s tumours model that is generated from correctly registered mammograms. The main purpose of this research is to come up with a 3D reconstruction method that can produce good breast cancer model from mammograms while using minimal computational cost.

Studying Palestinian-Israeli Relations at the Vanderbilt Television News Archive (VTNA)

2000 ◽  
Vol 34 (1) ◽  
pp. 38-40
Author(s):  
Deborah L. Wheeler
Keyword(s):  
Mass Media ◽  
Collective Identity ◽  
Television News ◽  
Building Blocks ◽  
Media Culture ◽  
The Past ◽  
Shared Identity ◽  
P 16 ◽  
The Creation ◽  
Words And Images

For the Past Five Decades, media texts, broadcast over television air waves, have created a shared identity among viewing audiences. John B. Thompson notes that if culture is understood as “the ways in which meaningful expressions of various kinds are produced, constructed and received by individuals”, then mass media can be understood as central to the creation and maintenance of culture (pp. 122-23). The words and images that construct a media culture are the very building blocks of collective identity. As Michael Schudson observes, “news is part of the background through which and with which people think” (p. 16).

scholarly journals A Fast and Effective Method to Identify Relevant Sets of Variables in Complex Systems

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1022
Author(s):  
Gianluca D’Addese ◽  
Martina Casari ◽  
Roberto Serra ◽  
Marco Villani
Keyword(s):  
Complex Systems ◽  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Computational Cost ◽  
Graph Analysis ◽  
The Past ◽  
Medium Level ◽  
Micro Level ◽  
Gene Regulatory ◽  
High Level

In many complex systems one observes the formation of medium-level structures, whose detection could allow a high-level description of the dynamical organization of the system itself, and thus to its better understanding. We have developed in the past a powerful method to achieve this goal, which however requires a heavy computational cost in several real-world cases. In this work we introduce a modified version of our approach, which reduces the computational burden. The design of the new algorithm allowed the realization of an original suite of methods able to work simultaneously at the micro level (that of the binary relationships of the single variables) and at meso level (the identification of dynamically relevant groups). We apply this suite to a particularly relevant case, in which we look for the dynamic organization of a gene regulatory network when it is subject to knock-outs. The approach combines information theory, graph analysis, and an iterated sieving algorithm in order to describe rather complex situations. Its application allowed to derive some general observations on the dynamical organization of gene regulatory networks, and to observe interesting characteristics in an experimental case.

Emulsion templated advanced functional materials from emerging nano building blocks

2021 ◽  
Author(s):  
Chenfei Yao ◽  
Ge Shi ◽  
Yijie Hu ◽  
Hao Zhuo ◽  
Zehong Chen ◽  
...  
Keyword(s):  
Transition Metal ◽  
Functional Materials ◽  
Building Blocks ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
The Past ◽  
Great Progress

The development of emulsion templated functional materials has achieved great progress in the past decades in academic and industrial fields. Recently, new building blocks such as graphene, transition metal carbides...

Bricks in the Making of Race and Place: Excavating a Lieu de Souvenir in New Orleans

2020 ◽  
Vol 70 (1) ◽  
pp. 7-32
Author(s):  
Angel Adams Parham
Keyword(s):  
New Orleans ◽  
Social Relationships ◽  
Cultural Practices ◽  
Building Blocks ◽  
The Past ◽  
Time Periods ◽  
Key Aspects ◽  
The City ◽  
Race And Place

This essay facilitates a multi-dimensional immersion into the life and rhythms of New Orleans, an entrée to the past that equips us to better understand the present and, from there, critically and creatively to envision our possible futures together. We explore the Faubourg Tremé by traversing layers of its lieux de souvenir - places of remembering, a concept inspired by but distinct from Pierre Nora’s lieux de mémoire - across three time periods. Each lieu de souvenir we visit from 1720 to the present will highlight material and symbolic foundations in Tremé that help us to understand key aspects of New Orleans’s past and present. The object that will guide our travel and meditation through each layer is the lowly but highly serviceable brick. At a purely material level, bricks are the literal building blocks of the city. Roads were paved with them and homes and other buildings were constructed with bricks as well. And at a symbolic level, bricks carry multiple rich and complex significations: Who makes them? How does their manufacturing shape the lives of the laborers who create them? Who buys them, and who profits from their sale? Tracing the brick and its uses throughout each lieu de souvenir sheds light on key social relationships, inequalities, and cultural practices that form the foundation of New Orleans’s past and present.

IBCube

2018 ◽  
Vol 15 (1) ◽  
pp. 27-46
Author(s):  
Qiong Hu ◽  
Hanhua Chen ◽  
Hai Jin ◽  
Chen Tian ◽  
Aobing Sun ◽  
...  
Keyword(s):  
Low Cost ◽  
Packet Delay ◽  
Building Blocks ◽  
Network Interface ◽  
Allocation Scheme ◽  
The Past ◽  
Datacenter Networks ◽  
Construction Scheme ◽  
Economical Design ◽  
Simulation Results

Datacenter networks have attracted a lot of research interest in the past few years. BCube is proved to be a promising scheme due to its low cost. By using a recursive construction scheme, BCube can exponentially scale a datacenter. Industry experiences, however, articulate the importance of incremental expansion of datacenter. In this article, the authors show that BCube's expanding scheme suffers low utilization of switch ports. They propose IBCube, a novel economical design for incrementally building datacenter networks. The insight is that: by letting the number of switches in each BCube layer equal the number of the building blocks, the authors can enable the switch ports to be fully utilized to support the total number of network interface cards of the deployed servers in the datacenters. Accordingly, their IBCube designs a novel automatic port allocation scheme. Simulation results show that the IBCube design reduces the budget for the datacenter networks by 94% as well as improves the packet delay and throughput by 10.3% and 11.5%, respectively, compared to the previous partial BCube design.

Randomized Hough Transform

2011 ◽  
pp. 1343-1350 ◽  
Author(s):  
Lei Xu ◽  
Erkki Oja
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Hough Transform ◽  
Random Sampling ◽  
Computational Cost ◽  
Detection Accuracy ◽  
The Past ◽  
Randomized Hough Transform ◽  
Dynamic Storage ◽  
High Computational Cost

Proposed in 1962, the Hough transform (HT) has been widely applied and investigated for detecting curves, shapes, and motions in the fields of image processing and computer vision. However, the HT has several shortcomings, including high computational cost, low detection accuracy, vulnerability to noise, and possibility of missing objects. Many efforts target at solving some of the problems for decades, while the key idea remains more or less the same. Proposed in 1989 and further developed thereafter, the Randomized Hough Transform (RHT) manages to considerably overcome these shortcomings via innovations on the fundamental mechanisms, with random sampling in place of pixel scanning, converging mapping in place of diverging mapping, and dynamic storage in place of accumulation array. This article will provides an overview on advances and applications of RHT in the past one and half decades.

scholarly journals Recent Advances in Palladium-Catalyzed Isocyanide Insertions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4906
Author(s):  
Jurriën W. Collet ◽  
Thomas R. Roose ◽  
Bram Weijers ◽  
Bert U. W. Maes ◽  
Eelco Ruijter ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Building Blocks ◽  
Insertion Reactions ◽  
Chemical Reagents ◽  
The Past ◽  
Recent Advances ◽  
Recent Developments ◽  
Palladium Catalyzed ◽  
Made In ◽  
Rapid Incorporation

Isocyanides have long been known as versatile chemical reagents in organic synthesis. Their ambivalent nature also allows them to function as a CO-substitute in palladium-catalyzed cross couplings. Over the past decades, isocyanides have emerged as practical and versatile C1 building blocks, whose inherent N-substitution allows for the rapid incorporation of nitrogeneous fragments in a wide variety of products. Recent developments in palladium catalyzed isocyanide insertion reactions have significantly expanded the scope and applicability of these imidoylative cross-couplings. This review highlights the advances made in this field over the past eight years.

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