Competitive Algorithms for Online Multidimensional Knapsack Problems

In this paper, we study the online multidimensional knapsack problem (called OMdKP) in which there is a knapsack whose capacity is represented in m dimensions, each dimension could have a different capacity. Then, n items with different scalar profit values and m-dimensional weights arrive in an online manner and the goal is to admit or decline items upon their arrival such that the total profit obtained by admitted items is maximized and the capacity of knapsack across all dimensions is respected. This is a natural generalization of the classic single-dimension knapsack problem and finds several relevant applications such as in virtual machine allocation, job scheduling, and all-or-nothing flow maximization over a graph. We develop two algorithms for OMdKP that use linear and exponential reservation functions to make online admission decisions. Our competitive analysis shows that the linear and exponential algorithms achieve the competitive ratios of O(θα ) and O(łogł(θα)), respectively, where α is the ratio between the aggregate knapsack capacity and the minimum capacity over a single dimension and θ is the ratio between the maximum and minimum item unit values. We also characterize a lower bound for the competitive ratio of any online algorithm solving OMdKP and show that the competitive ratio of our algorithm with exponential reservation function matches the lower bound up to a constant factor.

Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

<div>In this paper, we study to employ geographic information to address the blockage problem of air-to-ground links between UAV and terrestrial nodes. In particular, a UAV relay is deployed to establish communication links from a ground base station to multiple ground users. To improve communication capacity, we fifirst model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information. Then, an optimization problem is formulated to maximize the minimum capacity among users by jointly optimizing the 3-D position and power allocation of the UAV relay, under the constraints of link capacity, maximum transmit power, and blockage. To solve this complex non-convex problem, a two-loop optimization framework is developed based on Lagrangian relaxation. The outer-loop aims to obtain proper Lagrangian multipliers to ensure the solution of the Lagrangian problem converge to the tightest upper bound on the original problem. The inner-loop solves the Lagrangian problem by applying the block coordinate descent (BCD) and successive convex approximation (SCA) techniques, where UAV 3-D positioning and power allocation are alternately optimized in each iteration. Simulation results confifirm that the proposed solution signifificantly outperforms two benchmark schemes and achieves a performance close to the upper bound on the UAV relay system.</div>

The binder influence on the performance of positive electrodes of lithium-sulfur batteries

The comparison of performance of positive electrodes of lithium-sulfur batteries made using the binders based on fluoroplastic (PVDF Solef 5310 and Kynar) and polyethylene oxide (PEO) was carried out. The electrodes made using PVDF Kynar or limited amounts of PEO were shown to have certain advantages. It was also found that electrodes with PEO had an increased specific capacity during the initial period of cycling, whereas electrodes with Kynar were characterized by the minimum capacity fading during cycling.

DETERMINATION OF THE INTERNAL POTENTIAL OF ENERGY EFFICIENCY IN COMPOUND FEED PRODUCTION

Grass flour is a unique protein-vitamin feed product, the role of which in animal feeding can hardly be overestimated. In 2010, the industry for the production of grass meal from alfalfa, for example, in Europe included 300 factories and 50 farms, which produced 4200 million tons of products. In Russia, the development of poultry and livestock farming has also increased the demand for this fodder and gradually restored its production. But in Ukraine, due to its high energy intensity, the production of herbal flour has almost ceased. It is shown that the fuel and energy balance of this technology that diesel fuel provides about 92.3% of all equipment needs for energy, and its cost is 90.8% of the total cost of all fuel and energy resources (FER). On the other hand, electricity accounts for only 7.7% of the total needs, and the costs of paying for it also serve 9.2% of the total costs of purchasing fuel and energy resources.The purpose of the work is to study the energy feasibility of using extrusion for dehydration of wet feed products during their complex processing in feed products. To achieve this goal, the following tasks were solved: the selection and calculation of the necessary technological equipment for the principle technological scheme of the production of feed products with the inclusion of wet forage grasses was carried out; an energy audit of the basic (traditional) and new technologies for the production of compound feed products with the inclusion of forage grasses was carried out. Since the new technology is recommended to be implemented at feed mills of small capacity due to the proximity of raw materials, it must be able to process forage grasses in an amount no less than the basic technology for the production of grass meal. The minimum capacity of the ABM-type drying unit for cooking is 0.65 t/h for grass meal (2.7 t/h for raw materials). Thus, an energy audit of the basic (traditional) and new technology for the production of mixed feed products with the inclusion of forage grasses was carried out and proved that as a result of the use of the extrusion process for the purpose of dehydration, the new technology becomes more energy efficient in comparison with the traditional technology of drying forage grasses and further production of products with the inclusion of grass flour, which means it is economically feasible, since there is a total saving of fuel and energy resources of 875 MJ/t or - in the amount of 514.18 UAH (44%).

Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

<div>In this paper, we study to employ geographic information to address the blockage problem of air-to-ground links between UAV and terrestrial nodes. In particular, a UAV relay is deployed to establish communication links from a ground base station to multiple ground users. To improve communication capacity, we fifirst model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information. Then, an optimization problem is formulated to maximize the minimum capacity among users by jointly optimizing the 3-D position and power allocation of the UAV relay, under the constraints of link capacity, maximum transmit power, and blockage. To solve this complex non-convex problem, a two-loop optimization framework is developed based on Lagrangian relaxation. The outer-loop aims to obtain proper Lagrangian multipliers to ensure the solution of the Lagrangian problem converge to the tightest upper bound on the original problem. The inner-loop solves the Lagrangian problem by applying the block coordinate descent (BCD) and successive convex approximation (SCA) techniques, where UAV 3-D positioning and power allocation are alternately optimized in each iteration. Simulation results confifirm that the proposed solution signifificantly outperforms two benchmark schemes and achieves a performance close to the upper bound on the UAV relay system.</div>

Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

<div>In this paper, we study to employ geographic information to address the blockage problem of air-to-ground links between UAV and terrestrial nodes. In particular, a UAV relay is deployed to establish communication links from a ground base station to multiple ground users. To improve communication capacity, we fifirst model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information. Then, an optimization problem is formulated to maximize the minimum capacity among users by jointly optimizing the 3-D position and power allocation of the UAV relay, under the constraints of link capacity, maximum transmit power, and blockage. To solve this complex non-convex problem, a two-loop optimization framework is developed based on Lagrangian relaxation. The outer-loop aims to obtain proper Lagrangian multipliers to ensure the solution of the Lagrangian problem converge to the tightest upper bound on the original problem. The inner-loop solves the Lagrangian problem by applying the block coordinate descent (BCD) and successive convex approximation (SCA) techniques, where UAV 3-D positioning and power allocation are alternately optimized in each iteration. Simulation results confifirm that the proposed solution signifificantly outperforms two benchmark schemes and achieves a performance close to the upper bound on the UAV relay system.</div>

Survey of Work Zone Practices and Validation of Highway Capacity Manual Work Zone Capacity Model

Capacity at work zones is one of the major factors affecting queueing at work zones. Different states within the United States use their own methodology in determining work zone capacities and when to implement lane closures at work zones. The objective of this study was two-fold: first, to provide a synthesis of work zone lane closure procedures practiced by the various Departments of Transportation (DOTs) nationwide; and secondly, to validate the Highway Capacity Manual 6th edition’s (HCM 6) work zone capacity model using field-collected data in the state of Louisiana. The first objective was met by administering a survey to DOTs nationwide. The survey revealed that half of the states that responded to the survey require minimum capacity for short-term work zone lane closures, with minimum capacity ranging from 1100 to 1900 passenger cars per hour per lane. In addition, most of the states reported implementing consistent policies across various district offices. The survey findings provide a good source of information on queue analysis and work zone lane closure policies adopted across different DOTs. The second objective was met by collecting traffic flow data from 10 work zone sites within the state of Louisiana and validating the capacity model in the HCM 6. Results showed the HCM 6 model slightly overestimating the average field-observed capacity by 6%. In the absence of local data, the HCM 6 model provides a great tool to estimate work zone capacities in Louisiana.

Atomic Engineering Bifunctional Niobium (V)-based Heterostructure Nanosheet for High Efficiency Lean-Electrolyte Lithium-Sulfur Full Batteries

High-efficiency lithium-sulfur (Li-S) batteries depend on advanced electrode structure that can attain high sulfur utilization at lean-electrolyte and limited lithium. Herein, a twinborn holey Nb4N5-Nb2O5 heterostructure is designed as a dual-functional host for both redox-kinetics-accelerated sulfur cathode and dendrite-inhibited Li anode simultaneously for long-cycling and lean-electrolyte Li-S full batteries. Benefiting from the accelerative polysulfides anchoring-diffusion converting efficiency and electronic-conducting properties of Nb4N5-Nb2O5, polysulfide-shutting is significantly alleviated. Meanwhile, the lithiophilic nature of holey Nb4N5-Nb2O5 is applied as ion-redistributor for homogeneous Li-ion deposition. Taking advantage of these merits, the Li-S full batteries present the excellent electrochemical properties, including a minimum capacity decay of 0.025% per cycle, and a high areal-capacity of 5.0 mAh cm− 2 at sulfur loading of 6.9 mg cm− 2, corresponding to negative to positive capacity ratio (2.4:1) and electrolyte to sulfur ratio (5.1 µl mg− 1). Therefore, this work opens a new avenue for boosting high-performances Li-S batteries towards practical applications.

Gender Disparity in Educational Achievement in India

The primary objective of this chapter is to focus on progress of literacy achievement in India and factors influencing literacy rate are identified with regression models. A gender disparity index is prepared to analyse trends in differentials among male-female literacy achievement. India is now facing the challenge of achieving universalization of primary education to achieve status of a ‘literate country'. It is known fact that literacy and primary education are interdependent. A literate country will be a progressive-oriented country. It is observed that educational backwardness is due to various reasons like unsatisfactory progress of policy implementation, high level of illiteracy and dropout rates. Literacy rate is the best possible barometer to judge the level of educational awakening in a state, leading to a minimum capacity for self-learning. The empirical evidence substantiates the factors influencing educational achievement.

EVALUATION OF THE EFFICIENCY OF THE LOGISTICS COMPANY'S TRANSPORT PARK

The article is devoted to the conceptual issues of evaluation of the efficiency of the logistics company's transport park. The information base of the study is data of the real logistics network of one of the leading logistics companies in Dnipro, which has 42 branches. Based on the capabilities of the Google OR-Tools optimization package, a system of optimal transport routes for different fleet options has been built. According to the results of calculations, the transition from vehicles with higher capacity to lower capacity increases the number of passages and the length of the optimal route. Replacing the fleet of the largest load capacity (20 tons) with the smallest (1 ton) leads to considerable increasing of the optimal route’ length. Less capable vehicles are characterized by lower fuel consumption. But the results of calculating the total cost of implementing optimal routes proves that the transition from more capable to less capable vehicles is not effective. Indirect estimation of the efficiency of the combined fleet was built by gradually replacing of the minimum capacity vehicles in the fleet with the maximum capacity vehicles. For each such variant of the fleet, the optimal route was built, its length was recorded and fuel consumption was estimated. Estimation of fuel consumption was carried out by multiplying the length of mileage of large and small-capacity vehicles by the corresponding fuel consumption rates. Prospects for further research are to verify the results using alternative optimization tools. The results of the analysis indicate the effectiveness of building a transport fleet of logistics company based on heavy-duty vehicles. This approach reduces the number of pendulum routes and minimizes fuel consumption through the use of ring routes.