Digital phase shifters are widely used to achieve space scanning in phased array antenna, and beam pointing accuracy depends on the bit number and resolution of the digital phase shifter. This paper proposes a novel p...
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Digital phase shifters are widely used to achieve space scanning in phased array antenna, and beam pointing accuracy depends on the bit number and resolution of the digital phase shifter. This paper proposes a novel phase feeding method to reduce the phase quantization error effects. A linear formula for the beam pointing deviation of a linear uniform array in condition of phase quantization error is derived, and the linear programming algorithm is introduced to achieve the minimum beam pointing deviation. Simulations are based on the pattern of the phased array, which gives each element a certain quantization phase error to find the beam pointing deviation. The novel method is then compared with previous methods. Examples show that a 32-element uniform linear array with 5-bit phase shifters using the proposed method can achieve a higher beam-steering accuracy than the same array with 11-bit phase shifters.
linear programs are formulated which model the assignment of sanitation crews to shifts and days of the week such that payroll cost and missed refuse collection are balanced. The basic model is of a single district an...
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linear programs are formulated which model the assignment of sanitation crews to shifts and days of the week such that payroll cost and missed refuse collection are balanced. The basic model is of a single district and extensions to planning for sev eral districts simultaneously are pointed out. A special case is presented for which the optimal crew assignments are given by a simple rule. Models incorporating nonlinear penalties and less than daily pickup in which linearity is preserved are discussed.
The coefficient decimation technique for reconfigurable FIR filters was recently proposed as a filter structure with low computational complexity. In this brief, we propose to design these filters using linear program...
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The coefficient decimation technique for reconfigurable FIR filters was recently proposed as a filter structure with low computational complexity. In this brief, we propose to design these filters using linear programming taking all configuration modes into account, instead of only considering the initial reconfiguration mode as in previous works. Minimax solutions with significantly lower approximation errors compared to the straightforward design method in earlier works are obtained. In addition, some new insights that are useful when designing coefficient decimation filters are provided.
A linear programming model was employed to determine the optimal number of flue-cured tobacco markets for the Virginia-Carolinas region, as well as the optimal locations of these markets. The decisions were based on c...
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A linear programming model was employed to determine the optimal number of flue-cured tobacco markets for the Virginia-Carolinas region, as well as the optimal locations of these markets. The decisions were based on current market locations and county production figures. Solutions were obtained using an algorithm developed by Erlenkotter (1978). The algorithm obtained integer solutions through ascent and adjustment procedures using the dual of the linear program. The results indicated that the 53 markets currently in existence in the Virginia-Carolinas region should be consolidated, and many of the current markets should be closed. Assuming a market-opening fixed costs of $150,000 and a transportation cost of $0.004/kg-km, the optimal decision, based on minimizing total marketing cost, was to close 21 markets. This resulted in an annual savings of approximately $1,665,000 (9.1%) in the total cost of selling flue-cured tobacco in this region.
linear programming (LP) formulations are often employed to solve stationary, infinite-horizon Markov decision process (MDP) models. We present an LP approach to solving non-stationary, finite-horizon MDP models that c...
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linear programming (LP) formulations are often employed to solve stationary, infinite-horizon Markov decision process (MDP) models. We present an LP approach to solving non-stationary, finite-horizon MDP models that can potentially overcome the computational challenges of standard MDP solution procedures. Specifically, we establish the existence of an LP formulation for risk-neutral MDP models whose states and transition probabilities are temporally heterogeneous. This formulation can be recast as an approximate linear programming formulation with significantly fewer decision variables. (C) 2017 Elsevier B.V. All rights reserved.
In this paper, based on the nonparallel hyperplane classifier, nu-nonparallel support vector machine (nu-NPSVM), we proposed its linear programming formulation, termed as nu-LPNPSVM. nu-NPSVM which has been proved sup...
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In this paper, based on the nonparallel hyperplane classifier, nu-nonparallel support vector machine (nu-NPSVM), we proposed its linear programming formulation, termed as nu-LPNPSVM. nu-NPSVM which has been proved superior to the twin support vector machines (TWSVMs), is parameterized by the quantity nu to let ones effectively control the number of support vectors. Compared with the quadratic programming problem of nu-NPSVM, the 1-norm regularization term is introduced to nu-LPNPSVM to make it to be linear programming problem which can be solved fastly and easily. We also introduce kernel functions directly into the formulation for the nonlinear case. The numerical experiments on lots of data sets verify that our nu-LPNPSVM is superior to TWSVMs and faster than standard NPSVMs. We also apply this new method to the vehicle recognition problem and justify its efficiency. (C) 2016 Elsevier B.V. All rights reserved.
Objectives: To assess the nutritional quality of food aid delivered by food banks in France and to identify practical modifications to improve it. Design: National-level data were collected for all food aid distribute...
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Objectives: To assess the nutritional quality of food aid delivered by food banks in France and to identify practical modifications to improve it. Design: National-level data were collected for all food aid distributed by French food banks in 2004, and its nutrient content per 2000 kcal was estimated and compared with French recommendations for adults. Starting with the actual donation and allowing new foods into the food aid donation, linear programming was used to identify the minimum changes required in the actual donation to achieve the French recommendations. Results: French food-bank-delivered food aid does not achieve the French recommendations for dietary fibre, ascorbic acid, vitamin D, folate, magnesium, docosahexaenoic acid, alpha-linolenic acid and the percentage of energy from saturated fatty acids. linear programming analysis showed that these recommendations are achievable if more fruits, vegetables, legumes and fish were collected and less cheese, refined cereals and foods rich in fat, sugar and/or salt. In addition, new foods not previously collected are needed, particularly nuts, wholemeal bread and rapeseed oil. These changes increased the total edible weight (42%) and economic value (55%) of the food aid donation, with one-third of its edible weight coming from fruits and vegetables, one-third from staples, one-quarter from dairy products and approximately a tenth from meat/fish/eggs. Conclusions: Important changes in the types and amounts of food collected will improve the nutritional quality of food-bank-delivered food aid in France. Such changes are recommended to improve the diets of deprived French populations.
BACKGROUNDTo minimize the mortality rates of individuals affected by disasters, providing high-quality food relief during the initial stages of an emergency is crucial. The goal of this study was to develop a formulat...
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BACKGROUNDTo minimize the mortality rates of individuals affected by disasters, providing high-quality food relief during the initial stages of an emergency is crucial. The goal of this study was to develop a formulation for a high-energy, nutrient-dense prototype using linear programming (LP) model as a novel method for developing formulations for food products. RESULTSThe model consisted of the objective function and the decision variables, which were the formulation costs and weights of the selected commodities, respectively. The LP constraints were the Institute of Medicine and the World Health Organization specifications of the content of nutrients in the product. Other constraints related to the product's sensory properties were also introduced to the model. Nonlinear constraints for energy ratios of nutrients were linearized to allow their use in the LP. Three focus group studies were conducted to evaluate the palatability and other aspects of the optimized formulation. New constraints were introduced to the LP model based on the focus group evaluations to improve the formulation. CONCLUSIONLP is an appropriate tool for designing formulations of food products to meet a set of nutritional requirements. This method is an excellent alternative to the traditional trial and error' method in designing formulations. (c) 2017 Society of Chemical Industry
We study the intersection of finitely generated factor-free subgroups of free products of groups by utilizing the method of linear programming. For example, we prove that if H-1 is a finitely generated factor-free non...
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We study the intersection of finitely generated factor-free subgroups of free products of groups by utilizing the method of linear programming. For example, we prove that if H-1 is a finitely generated factor-free noncyclic subgroup of the free product G(1) * G(2) of two finite groups G(1), G(2), then the WN-coefficient sigma(H-1) of H-1 is rational and can be computed in exponential time in the size of H-1. This coefficient sigma (H-1)is the minimal positive real number such that, for every finitely generated factor-free subgroup H-2 of G(1)* G(2), it is true that (r) over bar (H-1, H-2) <= sigma (H-1) (r) over bar (H-1)(r) over bar (H-2), where (r) over bar (H) = max(r(H) - 1,0) is the reduced rank of H, r (H) is the rank of H, and (r) over bar (H-1, H-2) is the reduced rank of the generalized intersection of H-1 and H-2. In the case of the free product G(1) * G(2) of two finite groups G(1), G(2), it is also proved that there exists a factor-free subgroup H-2* = H-2*= (H-1) such that (r) over bar (H-1, H-2*) = sigma (H-1)(r) over bar (H-1)(r) over bar (H-2 ),H-2* has at most doubly exponential size in the size of H-1, and H-2* can be constructed in exponential time in the size of H-1.
The cost of earthwork involved in road construction can vary widely based on the roadway grades chosen by the designer. There is almost an infinite number of feasible grades available to the designer to choose from, a...
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The cost of earthwork involved in road construction can vary widely based on the roadway grades chosen by the designer. There is almost an infinite number of feasible grades available to the designer to choose from, all of which satisfy the geometric specification of the road. For every feasible grade selected, a transportation problem must be solved, which is a very tedious task. The roadway grade selection is usually considered as a stage and the earthwork (transportation) is another stage. These two stages have always been treated separately in the literature, The model presented here combines the roadway grade selection stage and the earthwork transportation stage in a single linear programming problem, thus guaranteeing global optimality.
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