scholarly journals ARRAY RADIATION PATTERN RECOVERY UNDER RANDOM ERRORS USING CLUSTERED LINEAR ARRAY

2022 ◽  
Vol 26 (1) ◽  
pp. 43-54
Author(s):  
Ahmed J. Abdulqader ◽  
◽  
Raad H. Thaher ◽  
Jafar R. Mohammed ◽  
◽  
...  
Keyword(s):  
Cost Function ◽  
Linear Array ◽  
Design Stage ◽  
Simulation Studies ◽  
Random Errors ◽  
Random Weight ◽  
Array Aperture ◽  
The Cost ◽  
The Impact ◽  
Entire Array

In practice, random errors in the excitations (amplitude and phase) of array elements cause undesired variations in the array patterns. In this paper, the clustered array elements with tapered amplitude excitations technique are introduced to reduce the impact of random weight errors and recover the desired patterns. The most beneficial feature of the suggested method is that it can be used in the design stage to count for any amplitude errors instantly. The cost function of the optimizer used is restricted to avoid any unwanted rises in sidelobe levels caused by unexpected perturbation errors. Furthermore, errors on element amplitude excitations are assumed to occur either randomly or sectionally (i.e., an error affecting only a subset of the array elements) through the entire array aperture. The validity of the proposed approach is entirely supported by simulation studies.

The effect of environmental regulations: a restricted cost function for Korean manufacturing industries

2007 ◽  
Vol 12 (1) ◽  
pp. 91-104 ◽  
Author(s):  
MYUNGHUN LEE
Keyword(s):  
Cost Function ◽  
Raw Materials ◽  
Environmental Regulations ◽  
Environmental Conservation ◽  
Manufacturing Industries ◽  
Parameter Estimates ◽  
Productive Activities ◽  
The Cost ◽  
The Impact ◽  
Percent Decline

Environmental conservation requires society to consider the trade-off between allocating resources to productive activities and pollution control activities. Therefore, it is informative to measure the effect of environmental regulations on firms' productivity. This paper attempts to estimate the impact of environmental regulations on Korean manufacturing industries. Despite being key inputs in the manufacturing process, raw materials have often been excluded from the cost function due to the lack of price data. A restricted cost function is used to improve the reliability of parameter estimates. Empirical results indicate that environmental regulations caused a 12 percent decline in the average annual rate of productivity growth over the period 1982–93.

scholarly journals The Impacts of Representing the Correlation of Errors in Radar Data Assimilation. Part I: Experiments with Simulated Background and Observation Estimates

2014 ◽  
Vol 142 (11) ◽  
pp. 3998-4016 ◽  
Author(s):  
Dominik Jacques ◽  
Isztar Zawadzki
Keyword(s):  
Data Assimilation ◽  
Cost Function ◽  
Radar Data ◽  
Spatial Correlations ◽  
Radar Observations ◽  
Lack Of Information ◽  
Data Thinning ◽  
The Cost ◽  
The Impact ◽  
Radar Data Assimilation

Abstract In radar data assimilation, statistically optimal analyses are sought by minimizing a cost function in which the variance and covariance of background and observation errors are correctly represented. Radar observations are particular in that they are often available at spatial resolution comparable to that of background estimates. Because of computational constraints and lack of information, it is impossible to perfectly represent the correlation of errors. In this study, the authors characterize the impact of such misrepresentations in an idealized framework where the spatial correlations of background and observation errors are each described by a homogeneous and isotropic exponential decay. Analyses obtained with perfect representation of correlations are compared to others obtained by neglecting correlations altogether. These two sets of analyses are examined from a theoretical and an experimental perspective. The authors show that if the spatial correlations of background and observation errors are similar, then neglecting the correlation of errors has a small impact on the quality of analyses. They suggest that the sampling noise, related to the precision with which analysis errors may be estimated, could be used as a criterion for determining when the correlations of errors may be omitted. Neglecting correlations altogether also yields better analyses than representing correlations for only one term in the cost function or through the use of data thinning. These results suggest that the computational costs of data assimilation could be reduced by neglecting the correlations of errors in areas where dense radar observations are available.

Role of computers in the design of energy-responsive buildings

1989 ◽  
Vol 16 (1) ◽  
pp. 55-61
Author(s):  
Radu Zmeureanu ◽  
Paul Fazio
Keyword(s):  
Structural Engineering ◽  
Building Design ◽  
Integrated Approach ◽  
Design Stage ◽  
Interactive Software ◽  
Cost Of Energy ◽  
Hollow Core Slab ◽  
The Cost ◽  
The Impact

Closer collaboration of the traditional disciplines of architecture, structural engineering, and mechanical engineering is required at the design stage to better deal with the complexity of modern buildings, and to maintain the cost of energy low while providing a suitable indoor environment during the life of the building.The availability of personal computers and the development of interactive software provide more opportunities for an integrated approach to building design. This approach is useful in determining the impact of one subsystem on the performance of another subsystem and on the overall performance of the building. An example of such an integrated approach is presented in this paper, which determines the impact of a structural system (hollow core slab) and its mass on the energy consumption of the building. Key words: building design, computers, energy.

scholarly journals On a Reduction for a Class of Resource Allocation Problems

2021 ◽  
Author(s):  
Martijn H. H. Schoot Uiterkamp ◽  
Marco E. T. Gerards ◽  
Johann L. Hurink
Keyword(s):  
Resource Allocation ◽  
Cost Function ◽  
Objective Function ◽  
Allocation Problem ◽  
Resource Allocation Problem ◽  
Special Cases ◽  
Input Parameters ◽  
The Cost ◽  
The Impact ◽  
Shared Structure

In the resource allocation problem (RAP), the goal is to divide a given amount of a resource over a set of activities while minimizing the cost of this allocation and possibly satisfying constraints on allocations to subsets of the activities. Most solution approaches for the RAP and its extensions allow each activity to have its own cost function. However, in many applications, often the structure of the objective function is the same for each activity, and the difference between the cost functions lies in different parameter choices, such as, for example, the multiplicative factors. In this article, we introduce a new class of objective functions that captures a significant number of the objectives occurring in studied applications. These objectives are characterized by a shared structure of the cost function depending on two input parameters. We show that, given the two input parameters, there exists a solution to the RAP that is optimal for any choice of the shared structure. As a consequence, this problem reduces to the quadratic RAP, making available the vast amount of solution approaches and algorithms for the latter problem. We show the impact of our reduction result on several applications, and in particular, we improve the best-known worst-case complexity bound of two problems in vessel routing and processor scheduling from [Formula: see text] to [Formula: see text]. Summary of Contribution: The resource allocation problem (RAP) with submodular constraints and its special cases are classic problems in operations research. Because these problems are studied in many different scientific disciplines, many conceptual insights, structural properties, and solution approaches have been reinvented and rediscovered many times. The goal of this article is to reduce the amount of future reinventions and rediscoveries by bringing together these different perspectives on RAPs in a way that is accessible to researchers with different backgrounds. The article serves as an exposition on RAPs and on their wide applicability in many areas, including telecommunications, energy, and logistics. In particular, we provide tools and examples that can be used to formulate and solve problems in these areas as RAPs. To accomplish this, we make three concrete contributions. First, we provide a survey on algorithms and complexity results for RAPs and discuss several recent advances in these areas. Second, we show that many objectives for RAPs can be reduced to a (simpler) quadratic objective function, which makes available the extensive collection of fast and efficient algorithms for quadratic RAPs to solve these problems. Third, we discuss the impact that RAPs and the aforementioned reduction result can make in several application areas.

scholarly journals Ensemble data assimilation of total column ozone using a coupled meteorology–chemistry model and its impact on the structure of Typhoon Nabi (2005)

2015 ◽  
Vol 15 (17) ◽  
pp. 10019-10031 ◽  
Author(s):  
S. Lim ◽  
S. K. Park ◽  
M. Zupanski
Keyword(s):  
Data Assimilation ◽  
Cost Function ◽  
Positive Impact ◽  
Eastern China ◽  
Chemical Information ◽  
Elevated Concentration ◽  
Total Column Ozone ◽  
Rms Error ◽  
The Cost ◽  
The Impact

Abstract. Ozone (O3) plays an important role in chemical reactions and is usually incorporated in chemical data assimilation (DA). In tropical cyclones (TCs), O3 usually shows a lower concentration inside the eyewall and an elevated concentration around the eye, impacting meteorological as well as chemical variables. To identify the impact of O3 observations on TC structure, including meteorological and chemical information, we developed a coupled meteorology–chemistry DA system by employing the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and an ensemble-based DA algorithm – the maximum likelihood ensemble filter (MLEF). For a TC case that occurred over East Asia, Typhoon Nabi (2005), our results indicate that the ensemble forecast is reasonable, accompanied with larger background state uncertainty over the TC, and also over eastern China. Similarly, the assimilation of O3 observations impacts meteorological and chemical variables near the TC and over eastern China. The strongest impact on air quality in the lower troposphere was over China, likely due to the pollution advection. In the vicinity of the TC, however, the strongest impact on chemical variables adjustment was at higher levels. The impact on meteorological variables was similar in both over China and near the TC. The analysis results are verified using several measures that include the cost function, root mean square (RMS) error with respect to observations, and degrees of freedom for signal (DFS). All measures indicate a positive impact of DA on the analysis – the cost function and RMS error have decreased by 16.9 and 8.87 %, respectively. In particular, the DFS indicates a strong positive impact of observations in the TC area, with a weaker maximum over northeastern China.

scholarly journals Investigation of the Effect of Slag Trap Design on Slag Delay Efficiency in the SolidWorks Flow Simulation Parametric Modeling Environment

2020 ◽  
pp. 108-117
Author(s):  
Serhii Kononchuk ◽  
◽  
Oleksandr Skrypnyk ◽  
Volodymyr Sviatskyi ◽  
Viktor Pukalov ◽  
...  
Keyword(s):  
Flow Rate ◽  
Field Experiments ◽  
Parametric Modeling ◽  
Design Stage ◽  
High Tech ◽  
Production Environment ◽  
Original Design ◽  
Trap Design ◽  
The Cost ◽  
The Impact

The most common technology for the manufacture of metal parts and work pieces is casting. High-tech branches of mechanical engineering require the production of high-quality castings of complex configuration from modern alloys with a given chemical composition and mechanical properties. The analysis of the causes of slag inclusions and ways to prevent them showed that in addition to technological means related to quality preparation of metal before pouring, a significant role is played by quiet continuous pouring of metal and properly designed foundry system, including slag trap. However, the use of the most common foundry systems (braking, throttle, with centrifugal slag traps, rain, siphon) to increase the efficiency of slag retention is associated with increased metal consumption, and as a consequence, leads to an increase in the cost of casting. Conducting experimental research by varying the design of the slag trap leads to an increase in the number of field experiments, given their complexity, limited by great difficulties. On the other hand, computer flow modeling allows to study the influence of slag trap design on the flow rate of the melt at the design stage and significantly reduce the cost of introduction of new castings. In order to reliably capture slag and reduce the speed of movement of the melt in the foundries, which provides a smooth filling of the form with an alloy, but without additional costs of metal, the original design of the ribbed slag catcher is proposed. The results of parametric modeling of the melt flow in the channel of the ribbed slag trap showed a decrease in the flow rate along the cross-sectional height of the slag trap compared to traditional by 0.028 m / s or 14.5%. This allowed to reduce the length of the slag trap to the first feeder. The expected metal savings are 0.26%. The form made using a 3D model of the slag trap showed satisfactory molding ability. But the obtained research results are of a recommendatory nature and require practical verification in the production environment. In addition, by varying parameters such as the height of the ribs, the distance between them, the angle of inclination, we can obtain similar results for different castings of different alloys. Given all this, there is a need for further study of the impact of the design of the slag trap on the efficiency of slag retention.

scholarly journals Impact of ozone observations on the structure of a tropical cyclone using coupled atmosphere–chemistry data assimilation

2015 ◽  
Vol 15 (8) ◽  
pp. 11573-11597
Author(s):  
S. Lim ◽  
S. K. Park ◽  
M. Zupanski
Keyword(s):  
Air Quality ◽  
Data Assimilation ◽  
Cost Function ◽  
Positive Impact ◽  
Eastern China ◽  
Chemical Information ◽  
Chemistry Data ◽  
Air Quality Forecast ◽  
The Cost ◽  
The Impact

Abstract. Since the air quality forecast is related to both chemistry and meteorology, the coupled atmosphere–chemistry data assimilation (DA) system is essential to air quality forecasting. Ozone (O3) plays an important role in chemical reactions and is usually assimilated in chemical DA. In tropical cyclones (TCs), O3 usually shows a lower concentration inside the eyewall and an elevated concentration around the eye, impacting atmospheric as well as chemical variables. To identify the impact of O3 observations on TC structure, including atmospheric and chemical information, we employed the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) with an ensemble-based DA algorithm – the maximum likelihood ensemble filter (MLEF). For a TC case that occurred over the East Asia, our results indicate that the ensemble forecast is reasonable, accompanied with larger background state uncertainty over the TC, and also over eastern China. Similarly, the assimilation of O3 observations impacts atmospheric and chemical variables near the TC and over eastern China. The strongest impact on air quality in the lower troposphere was over China, likely due to the pollution advection. In the vicinity of the TC, however, the strongest impact on chemical variables adjustment was at higher levels. The impact on atmospheric variables was similar in both over China and near the TC. The analysis results are validated using several measures that include the cost function, root-mean-squared error with respect to observations, and degrees of freedom for signal (DFS). All measures indicate a positive impact of DA on the analysis – the cost function and root mean square error have decreased by 16.9 and 8.87%, respectively. In particular, the DFS indicates a strong positive impact of observations in the TC area, with a weaker maximum over northeast China.

Landing Motion of a Legged Robot with Minimization of Impact Force and Joint Torque

2015 ◽  
Vol 27 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Xianglong Wan ◽  
◽  
Takateru Urakubo ◽  
Yukio Tada
Keyword(s):  
Cost Function ◽  
Numerical Optimization ◽  
Impact Force ◽  
Contact Point ◽  
Joint Torque ◽  
Legged Robot ◽  
Joint Torques ◽  
Singular Configuration ◽  
The Cost ◽  
The Impact

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270001/04.jpg"" width=""300"" />Optimal motion of a legged robot</div> This paper deals with an optimal landing motion of a four-link legged robot that minimizes the impact force at the contact point and the joint torques necessary during the motion. The cost function for optimization is given as the weighted sum of the impact force and the joint torques. The configuration of the robot that is close to a singular configuration is advantageous in minimizing the joint torques for a heavy torso, while the configuration where the leg is bent is advantageous in reducing the impact force. This is shown by numerical optimization results with different weights for the cost function and a theoretical analysis of a simplified model of the robot. </span>

scholarly journals The Impact of Temporary Means of Access on Buildings Envelope’s Maintenance Costs

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 601
Author(s):  
Cláudia Ferreira ◽  
Ilídio S. Dias ◽  
Ana Silva ◽  
Jorge de Brito ◽  
Inês Flores-Colen
Keyword(s):  
Sensitivity Analysis ◽  
Building Envelope ◽  
Design Stage ◽  
Maintenance Costs ◽  
Alternative Means ◽  
Tiling Systems ◽  
Maintenance Work ◽  
Surrounding Space ◽  
The Cost ◽  
The Impact

Accessibility to buildings’ envelope depends on efficient inspection and other maintenance actions of their components. When access to these components is not planned, special means of access are required to carry out the maintenance work. Means of access, besides having a fundamental role on the quality of maintenance works of building envelope components, also represents a considerable part of the maintenance costs. Thus, to optimize costs and resources in maintenance plans, assessment of the impact of the means of access on maintenance costs is crucial. For works in height, there are several alternative means of access. The choice of the most adequate solution is strongly linked to the characteristics (e.g., architecture, height) and constraints (e.g., users, surrounding space) of each building, the maintenance needs of the envelope, and the time and funds available for the intervention. Therefore, in this study, a sensitivity analysis to understand how the cost of means of access can influence the maintenance costs is carried out. Moreover, the optimisation of maintenance activities in façade claddings is also analysed. This study intends to assess whether it is advantageous to consider permanent means of access during the design phase or opt for temporary means of access. In a first stage, the impact of six temporary means of access (supported and suspended scaffolds; articulated booms; telescopic booms; scissor lifts; and rope access) on the maintenance plans developed for the six types of claddings (ceramic tiling systems—CTS, natural stone claddings—NSC, rendered façades—RF, painted surfaces—PS, external thermal insulation composite systems—ETICS, and architectural concrete façades—ACF) is examined. The impact is estimated through a stochastic maintenance model based on Petri nets. After that, a sensitivity analysis and a multi-criteria decision analysis are performed. Based on the results, general recommendations are presented concerning the maintenance strategies to adopt in the cladding solutions analysed. The results reveal that planning the means of access during the design stage can be economically beneficial for all buildings’ envelope components.

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