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We introduce a novel graph called a host-switch graph, which consists of host vertices and switch vertices. Using host-switch graphs, we formulate a graph problem called an order/radix problem (ORP) for designing low end-to-end latency interconnection networks. Our focus is on reducing the host-to-host average shortest path length (h-ASPL), since the shortest path length between hosts in a host-switch...
As a kind of novel porous structure with high strength relative to low mass, lattice structure infilling can attain a lightweight structure while maintaining the high specific mechanical properties in the 3D solid structures. Focusing on the deficiency of the non-optimized macro-material distribution in the traditional lattice infilling, a design and modeling method of variable-density 3D lattice...
Network lifetime is of great importance in WBANs that significantly influences the network performance and user experience. Among all the solutions to extend the network lifetime, relay mechanism plays a crucial role. However, previous works only concentrate on energy efficiency of sensor nodes regardless of energy storage diversity among sensor nodes, which may severely limit the performance of enhancing...
For a linear system that has a pole in the open right-half plane and is subject to actuator saturation, global asymptotically stabilization cannot be achieved. As a result, a multi-agent system containing such an actuator saturating agent can only reach regional consensus, that is, consensus can be achieved only when the initial state of each agent resides in a region of the state space. The region...
In this paper, we consider the privacy preserving problem of consensus protocol. First, we introduce a privacy preserving scheme, where each node produces and transmits a sequence of random values with their mean equaling to the node's initial state. We show that the network can reach average consensus with privacy preserving scheme, and provide a sufficient condition under which the initial state...
A comparative analysis of the plug-in fuel cell vehicles (PFCV) is studied regarding different topologies, drive cycles and control strategies. To improve the performance of the PFCV, an optimization strategy is proposed at first by regulating the power distribution between the battery and the PEMFC system. Then, a direct multiple shooting (DMS) algorithm is used to solve this nonlinear programming...
Energy consumption has become a key issue for running large-scale data center networks (DCN) nowadays. Previous studies mainly focus on energy saving through reducing the number of active servers or network switches with traffic consolidation. However, since this mechanism benefits from the routing flexibility, both the gained energy savings and flow performance are limited by the conventional static...
Competitive swarm optimizer (CSO) has shown promising results for solving large scale global optimization problems proposed recently. However, CSO shows insufficient exploitation of the population. In this paper, a competitive swarm optimizer integrated with Cauchy and Gaussian mutation (CGCSO) is proposed for large scale optimization. The new algorithm does not only update the losers' positions with...
Data aggregation is a critical operation in many big-data applications; for example, data residing in several source racks (mappers) are to be aggregated into one or more specified racks called aggregators (reducers) in the data center network during the shuffle phase of a map-reduce task. In this paper, we explore algorithms for data aggregation to two aggregators in a data center network under the...
In this paper, we concentrate on multi-target fusion and tracking problems in wireless sensor network (WSN) based on distributed clustering consensus filter. In particular, for the sake of the network lifetime and the tracking accuracy in multi-target cases, a distributed target-based clustering algorithm is proposed, which consists of the cluster member selection, the cluster head competition and...
This paper introduces a high-power-density low-profile dc-dc converter for cellphone battery charging applications. The converter delivers 40 W across a 4:1 input voltage range with a nominal input voltage of 12 V and a nominal output voltage of 4 V. The PCB area of the converter is limited to 80 mm2 and the component height is limited to 1 mm. Three alternative topologies — a zero-voltage switching...
We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization.
For a discrete-time linear system that has an open-loop pole outside the unit circle and is subject to actuator saturation, global asymptotic stabilization cannot be achieved. As a consequence, a discrete-time multi-agent system containing such an actuator saturating agent can only reach regional consensus, that is, the consensus can be achieved only if the initial state of each agent resides in a...
Differential evolution (DE) is an efficient and robust evolutionary algorithm, which has been widely and successfully applied to solve global optimization problems. Although many methods have been developed based on the population topology to improve the performance of DE, the effects of population topology interacted with the functions being optimized are not considered in most of the algorithm designs...
We consider the design of individual and periodic arrangements of metal or semiconductor nanoparticles for localized electromagnetic field enhancement utilizing a topology optimization based numerical framework as the design tool. We aim at maximizing a function of the electromagnetic field amplitude in a region of space through the introduction of nanoparticles in and/or near the region.
In this paper, system framework for UAV formation collision avoidance is proposed. Key modules of the framework are identified including collaborative sensing, threat assessment, formation reorganization, path planning and maneuver control. Their corresponding mathematical models are also established for performance optimization. The formation collision avoidance is finally formulated as a combined...
The flexure hinge is a key component for designing compliant mechanisms that have been widely used in precision engineering which high positioning accuracy is demanded. This paper presents a systematic method for designing flexure hinges by using the topology optimization method. An optimization model is developed by equally considering the following three objectives: (I) maximizing the compliance...
The development of optimal XY θz flexure mechanisms, which can deliver high precision motion about the z-axis, and along the x- and y-axes is highly desirable for a wide range of micro/nano-positioning tasks pertaining to biomedical research, microscopy technologies and various industrial applications. Although maximizing the stiffness ratios is a very critical design requirement, the achievable translational...
We introduce a logical theory of differentiation for a real-valued function on a finite dimensional real Euclidean space. A real-valued continuous function is represented by a localic approximable mapping between two semi-strong proximity lattices, representing the two stably locally compact Euclidean spaces for the domain and the range of the function. Similarly, the Clarke subgradient, equivalently...
The modern Distribution Systems (DS) require for accurate and fast Power Flow (PF) algorithms as a basis for other DS applications. Almost all decisions are taken based on accurate PF results and, possibly, they have to be taken in real time. In this paper, a new PF algorithm based on a linear programming approach is proposed. The graph theory is used for modeling the distribution network with some...
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