Abstract-Three dimensional (3D) printing can be used to manufacture many different objects range from toys to hitech robot parts. This paper investigates 3D printer trajectory planning to improve the speed of the printing process. The printing speed mainly depends on the motion speed and path of the printing nozzle. We use triangular and trapezoidal velocity profiles to minimize the transition time between print segments. In this work, several algorithms that were originally proposed as solutions for conventional traveling salesman problem are modified to adapt to the new problem. The proposed modifications are designed to obtain time-efficient trajectories for the printing nozzle.

Abstract-Internet of Things (IoT) systems comprise massive volumes of smart devices. Through exchanges of information, smart objects are capable of reasoning and generate higher level of intelligence. The effectiveness of data collection processes is a key factor to the success of IoT systems as it can seriously affect the freshness of the captured data. Efficient data collection processes have been well-studied on sensory systems with static topologies and single data extraction point. Smart devices in IoT systems are often shared by different parties, therefore concurrent data collection processes are always expected. Such a unique characteristic of IoT systems has imposed new challenges to the designs of efficient data collection processes. In this paper, concurrent data collection trees specifically designed for IoT applications are proposed. It is shown that, comparing with an existing single-user data collection structure, systems with the proposed tree structures can significantly shorten their concurrent data collection processes.

Layered additive manufacturing, also known as 3D printing, has revolutionized transitional manufacturing processes. Fabrication of 3D models with complex structures is now feasible with 3D printing technologies. By performing careful tool-path optimization, the printing process can be speeded up, while the visual quality of printed objects can be improved simultaneously. The optimization process can be perceived as an undirected rural postman problem (URPP) with multiple constraints. In this paper, a tool-path optimizer is proposed, which further optimizes solutions generated from a slicer software to alleviate visual artifacts in 3D printing and shortens print time. The proposed optimizer is based on a modified ant colony optimization (ACO), which exploits unique properties in 3D printing. Experiment results verify that the proposed optimizer can deliver significant improvements in computational time, print time, and visual quality of printed objects over optimizers based on conventional URPP and ACO solvers.

Abstract-It is always challenging for deaf and speechimpaired people to communicate with non-sign language users. A real-time sign language recognition system using 3D motion sensors could lower the aforementioned communication barrier. However, most existing gesture recognition systems are adopting a single sensor framework, whose performance is susceptible to occlusions. In this paper, we proposed a real-time multisensor recognition system for American sign language (ASL). Data collected from Leap Motion sensors are fused using multiple sensors data fusion (MSDF) and the recognition is performed using hidden Markov models (HMM). Experimental results demonstrate that the proposed system can deliver higher recognition accuracy over single-sensor systems. Due to its low implementation cost and higher accuracy, the proposed system can be widely deployed and bring conveniences to sign language users.

Abstract-Virtualization is the enabling technology that makes resource provisioning in Cloud computing feasible. With virtualization, virtual machines (VMs) can be migrated across physical hosts to achieve better utilization of resource with a minimum impact on service quality. The VM allocation problem can be formulated as a stable matching problem. In this paper, we propose a VM allocation mechanism based on stable matching. A deferred acceptance procedure is adopted to handle conflicts among preferences of VMs and physical hosts. Unlike ordinary stable matching problems, both involving party groups in our matching process are having a mutual objective, that is to reduce the overall energy consumption of a Cloud data center while maintaining a high level of Quality of Service. The proposed mechanism is evaluated using CloudSim with real-world workload data. Simulation results show that Cloud data centers with the proposed mechanism can reduce energy consumption and avoid violations of ServiceLevel Agreement.