Design of Minimal-Weight Structures for Given Reliability and Cost

1962 ◽  
Vol 29 (3) ◽  
pp. 355-356 ◽  
Author(s):  
Robert Kalaba
Keyword(s):  
Minimal Weight ◽  
Weight Structures

Optimal Design of Structural Shape: Minimal Weight Shapes Designed Corresponding to Displacement Restraining Planes

1992 ◽  
Author(s):  
Motomichi Itou ◽  
Teiichi Ohkouchi
Keyword(s):  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Descent Method ◽  
Steepest Descent Method ◽  
External Boundary ◽  
Structural Shape ◽  
Cross Sectional ◽  
Minimal Weight ◽  
Nodal Displacements ◽  
Weight Structures

Abstract The designs of the elastic two-dimensional plate structure are optimized for the minimal weight structures of the characteristic shapes. Structures composed of finite elements are modified discretely by attaching and detaching of elements at external boundary of shapes. In the modifications, the steepest descent method is actualized using the sensitivity function that is evaluated from the strain energy of the structure by Finite Element Method. The sensitivity value of each element is calculated by the element stiffness matrix and the nodal displacements. The two structures “A” and “B” are modified by the above mention technique. The structure “A” with vertical and horizontal displacement restraining planes is converged into a hanging bar with a uniform cross-sectional area of the minimal weight shape. The structure “B” with only vertical displacement restraining plane is converged into a V-shaped structure supported by two forked ends.

scholarly journals Feasibility Study on the Development of a Deployable Tactical EMP Tent for a Sustainable Military Facility

2020 ◽  
Vol 13 (1) ◽  
pp. 16
Author(s):  
Kukjoo Kim ◽  
Kyung-Ryeung Min ◽  
Young-Jun Park
Keyword(s):  
Korean Peninsula ◽  
Military Operations ◽  
Shielding Effectiveness ◽  
Electromagnetic Pulses ◽  
Fixed Weight ◽  
Operational Readiness ◽  
The Military ◽  
Transaction Price ◽  
Delphi Analysis ◽  
Weight Structures

The Korean peninsula is under increasing threat of electromagnetic pulses (EMPs) from neighboring countries; EMP protection facilities are an essential means of ensuring the operational readiness of the military. However, existing EMP protection facilities are manufactured as fixed-weight structures, which limit the mobility of military operations and lead to the misconception of EMP protection as something only required for higher command. The current military and official EMP protection standards require only a uniform shielding effectiveness of 80 dB. Therefore, this study aims to differentiate the existing uniform level of shielding effectiveness of 80 dB into 80 dB, 60 dB, 40 dB, etc. Further, it seeks to derive the factors to be considered when applying various methods, such as shielding rooms, shielding racks, site redundancy, spare equipment, and portable lightweight protective tents, for recovery of failure, instead of the existing protection facilities that rely on shielded rooms by the Delphi analysis. Then, the applicability of lightweight EMP protection is determined after selecting lightweight materials to build a facility. The electromagnetic shielding performance of 21 types of materials was measured in the 30 MHz–1.5 GHz frequency band using ASTM-D-4935-10. The results showed the possibility of developing a lightweight EMP shielding facility, which would save approximately 316,386 tons of concrete, reducing the CO2 emissions by approximately 9,972,489 tons. Assuming that the Korean carbon transaction price is USD 50/ton CO2, the savings are equivalent to USD 49,862,435.

Wrestlers?? minimal weight

1991 ◽  
Vol 23 (2) ◽  
pp. 247???253 ◽  
Author(s):  
ROBERT A. OPPLIGER ◽  
DAVID H. NIELSEN ◽  
CAROL G. VANCE
Keyword(s):  
Minimal Weight

Selection of the Optimal Structural Design of a Spar Composite Wing

2021 ◽  
pp. 90-99
Author(s):  
O.V. Tatarnikov ◽  
W.A. Phyo ◽  
Lin Aung Naing
Keyword(s):  
Optimal Design ◽  
Element Analysis ◽  
Minimal Weight ◽  
Wing Structures ◽  
Optimization Parameters ◽  
Nonlinear Static ◽  
Wing Structure ◽  
Pareto Method ◽  
Selection Of ◽  
Composite Wing

This paper describes a method for optimizing the design of a spar-type composite aircraft wing structure based on multi-criterion approach. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal design of a wing frame was determined by the Pareto method basing on three criteria: minimal weight, minimal wing deflection, maximal safety factor and minimal weight. Positions of wing frame parts, i.e. spars and ribs, were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed. All the calculations necessary to select the optimal structural and design of the spar composite wing were performed using nonlinear static finite element analysis in the FEMAP with NX Nastran software package.

scholarly journals Complexity of Error-Correcting Code Based on Nearest Neighbor Search Algorithm

2019 ◽  
pp. 7-20
Author(s):  
Levon Arsalanyan ◽  
Hayk Danoyan
Keyword(s):  
Time Complexity ◽  
Nearest Neighbor ◽  
Search Algorithm ◽  
Error Correcting Code ◽  
Error Correcting Codes ◽  
Code Word ◽  
Nearest Neighbor Search ◽  
Perfect Codes ◽  
Neighbor Search ◽  
Weight Structures

The Nearest Neighbor search algorithm considered in this paper is well known (Elias algorithm). It uses error-correcting codes and constructs appropriate hash-coding schemas. These schemas preprocess the data in the form of lists. Each list is contained in some sphere, centered at a code-word. The algorithm is considered for the cases of perfect codes, so the spheres and, consequently, the lists do not intersect. As such codes exist for the limited set of parameters, the algorithm is considered for some other generalizations of perfect codes, and then the same data point may be contained in different lists. A formula of time complexity of the algorithm is obtained for these cases, using coset weight structures of the mentioned codes

scholarly journals Constructions of vector-valued modular forms of rank four and level one

2020 ◽  
Vol 16 (05) ◽  
pp. 1111-1152
Author(s):  
Cameron Franc ◽  
Geoffrey Mason
Keyword(s):  
Irreducible Representation ◽  
Differential Equations ◽  
Modular Forms ◽  
Modular Group ◽  
Tensor Products ◽  
Two Dimensional ◽  
Minimal Weight ◽  
Graded Module ◽  
Holomorphic Modular Forms ◽  
Vector Valued

This paper studies modular forms of rank four and level one. There are two possibilities for the isomorphism type of the space of modular forms that can arise from an irreducible representation of the modular group of rank four, and we describe when each case occurs for general choices of exponents for the [Formula: see text]-matrix. In the remaining sections we describe how to write down the corresponding differential equations satisfied by minimal weight forms, and how to use these minimal weight forms to describe the entire graded module of holomorphic modular forms. Unfortunately, the differential equations that arise can only be solved recursively in general. We conclude the paper by studying the cases of tensor products of two-dimensional representations, symmetric cubes of two-dimensional representations, and inductions of two-dimensional representations of the subgroup of the modular group of index two. In these cases, the differential equations satisfied by minimal weight forms can be solved exactly.

scholarly journals On constructing weight structures and extending them to idempotent completions

2018 ◽  
Vol 20 (1) ◽  
pp. 37-57 ◽  
Author(s):  
Mikhail V. Bondarko ◽  
Vladimir A. Sosnilo
Keyword(s):  
Weight Structures

scholarly journals Minimal Weight in Union-Closed Families

10.37236/582 ◽  
2011 ◽  
Vol 18 (1) ◽  
Author(s):  
Victor Falgas-Ravry
Keyword(s):  
Lower Bound ◽  
Related Question ◽  
Average Degree ◽  
Additional Information ◽  
Minimal Weight ◽  
Multiplicative Factor ◽  
Finite Set

Let $\Omega$ be a finite set and let $\mathcal{S} \subseteq \mathcal{P}(\Omega)$ be a set system on $\Omega$. For $x\in \Omega$, we denote by $d_{\mathcal{S}}(x)$ the number of members of $\mathcal{S}$ containing $x$. A long-standing conjecture of Frankl states that if $\mathcal{S}$ is union-closed then there is some $x\in \Omega$ with $d_{\mathcal{S}}(x)\geq \frac{1}{2}|\mathcal{S}|$. We consider a related question. Define the weight of a family $\mathcal{S}$ to be $w(\mathcal{S}) := \sum_{A \in \mathcal{S}} |A|$. Suppose $\mathcal{S}$ is union-closed. How small can $w(\mathcal{S})$ be? Reimer showed $$w(\mathcal{S}) \geq \frac{1}{2} |\mathcal{S}| \log_2 |\mathcal{S}|,$$ and that this inequality is tight. In this paper we show how Reimer's bound may be improved if we have some additional information about the domain $\Omega$ of $\mathcal{S}$: if $\mathcal{S}$ separates the points of its domain, then $$w(\mathcal{S})\geq \binom{|\Omega|}{2}.$$ This is stronger than Reimer's Theorem when $\vert \Omega \vert > \sqrt{|\mathcal{S}|\log_2 |\mathcal{S}|}$. In addition we construct a family of examples showing the combined bound on $w(\mathcal{S})$ is tight except in the region $|\Omega|=\Theta (\sqrt{|\mathcal{S}|\log_2 |\mathcal{S}|})$, where it may be off by a multiplicative factor of $2$. Our proof also gives a lower bound on the average degree: if $\mathcal{S}$ is a point-separating union-closed family on $\Omega$, then $$ \frac{1}{|\Omega|} \sum_{x \in \Omega} d_{\mathcal{S}}(x) \geq \frac{1}{2} \sqrt{|\mathcal{S}| \log_2 |\mathcal{S}|}+ O(1),$$ and this is best possible except for a multiplicative factor of $2$.

Sign in / Sign up

Export Citation Format

Share Document