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We consider the problem of partitioning clinical services in hospitals into groups with the goal of efficiently allocating existing inpatient beds. At the strategic level, there are two major possibilities: pooling versus focusing. Pooling the bed capacity allows one to achieve an overall high occupancy level for a fixed number of beds. On the other hand, focusing by dividing the capacity into groups...
We consider the problem of partitioning clinical services in hospitals into groups with the goal of efficiently allocating existing inpatient beds. At the strategic level, there are two major possibilities: pooling versus focusing. Pooling the bed capacity allows one to achieve an overall high occupancy level for a fixed number of beds. On the other hand, focusing by dividing the capacity into groups...
The femtocell is a promising technology that can be employed to enhance next generation wireless network coverage. It possesses the potential to reduce network deployment risk, improve network operation efficiency and capacity. By utilizing femtocells spectrum utilization can be improved. Due to its key features, including low cost, high speed, and plug and play capability, network operators should...
We analyze moment-based bounding approximations on the expected value of a utility function. We show that optimizing these bounds yields a solution, which is mean-variance (MV) or MV-skewness-kurtosis (MVSK) efficient depending on how many moments are included in the approximation. To illustrate the approach we apply it to an asset allocation model with a shortfall utility function. Numerical results...
With the application of modern communication, control and measurement technology based on microelectronics and computer, a large number of microelectronic devices have been applied in the power generation, transmission and production links of power plants. In order to ensure the safe operation of all kinds of electronic equipment, it is necessary to install surge protector (SPD). In this paper, MATLAB...
Large-scale systems use distributed data processing systems in their work. An important problem in the design of such systems is the optimal allocation of data files by the nodes of the computer network. The article deals with the problem of the optimal allocation of files and their copies over the nodes of an unreliable large-scale distributed system.
The natural disasters affecting railway are characterized by universality, frequency and variety in china. These events can suddenly cause a greater negative impact on the order of rail transport organizations in a short time. The abnormal circumstances of network node or network range will pose a threat to the safety and efficiency of rail transport. On the basis of analyzing the causes of the problem...
In this paper, we jointly consider communication, caching and computation in a multi-user cache-assisted mobile edge computing (MEC) system, consisting of one base station (BS) of caching and computing capabilities and multiple users with computation-intensive and latency-sensitive applications. We propose a joint caching and offloading mechanism which involves task uploading and executing for tasks...
This paper proposes a novel approach to integrate plugged-in electric vehicles (PEVs), electric vehicle supply equipments (EVSEs), and smart grid (SG) infrastructure using state of the art software-defined network (SDN) technology, which has a potential to provide unprecedented flexibility to smart grid communication network. We further present set-cardinality based search algorithms for assigning...
To satisfy various quality-of-service (QoS) requirements of different services in future fifth generation wireless networks, wireless virtualized network (WVN) architectures have been proposed to concurrently fulfill diversified service demands via network slicing technologies. Considering the dynamic characteristics of wireless channels and user traffic, the resource allocation problem in a WVN with...
In this paper, we investigate the modulation order selection and power allocation for energy efficient (EE) orthogonal frequency division multiplexing (OFDM) visible light communication (VLC) systems. Unlike the widely studied Gaussian inputs, we consider that each subcarrier has discrete modulation scheme inputs. Under the constraints of the maximum total transmission power and the minimum spectral...
In order to reduce the effect of pilot contamination and maximize the system sum rate while guaranteeing the fairness among users, an efficient and fair pilot allocation scheme is proposed for multi-cell massive MIMO systems in this work. The pilot allocation optimization problem is formulated to maximize the sum rate of the system while guaranteeing the fairness among users. A heuristic algorithm,...
Due to the limited frequency and energy resources, cooperative satellite communication (SATCOM) systems have been widely studied. To improve the spectrum efficiency further, we propose to combine non-orthogonal multiple access (NOMA) with cooperative SATCOM systems in this paper. Under the condition of fixed total transmit power, an optimization problem is formulated to maximize the sum-rate with...
In this paper, we study the energy-efficient user access control (UAC) based on resource allocation (RA) in heterogeneous cellular networks (HCNs) with the required downlink data rate under non-ideal power amplifiers (PAs) and circuit power. It is proved that the energy consumption minimization is achieved when the typical user accesses only one base station (BS), while the other BSs remain in idle...
This paper investigates the resource allocation problem in heterogeneous cognitive radio networks (HCRNs). In this paper, two types of users, i.e., multi-homing and single-network cognitive radio users (CRUs), are considered to coexist in HCRNs. Multi-homing CRUs can access multiple networks simultaneously, while single-network CRUs can be served by only one network at a time. With the aim of maximizing...
Distributed generation (DG) is utilized in electric power networks for the purpose of loss reduction, environment friendly features, and voltage improvement. This paper determines optimal allocation of DGs through Multi-Objective Index (MOI) for improving voltage stability and decreasing line losses of radial distribution system. Multiple objectives are merged using weighting factors and investigated...
Based on the problem of the multi-objective spectrum allocation on the joint optimization of maximal network utility and the fairness of users in the cognitive network, a novel adaptive fruit fly algorithm (FOA) for channel (i.e. spectrum) scheduling is proposed, which can make both of primary users (PUs) and cognitive nodes (CNs) access to the available wireless channels. In the present algorithm,...
Edge computing, which is a fundamental component of emerging 5G architectures, involves onloading or offloading multiple virtual network functions from mobile devices to an edge network substrate. In this paper, we present a model for the complete edge function onloading problem, which consists of three main phases: (1) Cyber foraging, which involves discovery of resources monitoring the state of...
In this paper, we study the physical layer security in the downlink Non-Orthogonal Multiple Access (NOMA) systems with the capability of simultaneous wireless information and power transfer (SWIPT). In our system, each user applies the optimum power splitting (PS), in order to coordinate the energy harvesting and information decoding at the receiver. The optimization problem is formulated as the optimal...
Non-Orthogonal Multiple Access (NOMA) is a promising multiple access technique for 5G wireless communication networks due to its higher spectral efficiency and user fairness. Power allocation is the key to improve the performance of NOMA systems. In this paper, we focus on a certain NOMA group of a hybrid NOMA system. We formulate a sum-throughput maximization problem for uplink under the constraints...
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