Traditional Layered Approach Research Articles

Volumetric 3D Printing of Endoskeletal Soft Robots.

Computed Axial Lithography (CAL) is an emerging technology for manufacturing complex parts, all at once, by circumventing the traditional layered approach using tomography. Overprinting, a unique additive manufacturing capability of CAL, allows for a 3D geometry to be formed around a prepositioned insert where the occlusion of light is compensated for by the other angular projections. This method opens the door for novel applications within additive manufacturing for multi-material systems such as endoskeletal robots. Herein, this work presents one such application with a simple Gelatin Methacrylate (GelMA)hydrogel osmotic actuator with an embedded endoskeletal system. GelMA is an ideal material for this application as it is swellable and has reversible thermal gelation, enabling suspension of the endoskeleton during printing. By tuning the material formulation, the actuator design, and post-processing, swelling-induced bending actuation of 60 degrees is achieved. To aid in the printing process, a simple computational method for determining the absolute dose absorbed by the resin allowing for print time prediction is also proposed.

Secure cross-layer routing protocol with authentication key management scheme for manets

MANET (Mobile ad-hoc networks) is typically a no-infrastructure multi-hop network where every node interacts with other network nodes either indirectly or directly via intermediate nodes. A lot of research is being undertaken to save the energy of mobile nodes at different levels. Power-relevant issues can have an effect on every layer of the stack, making the traditional layered approach ineffective. In this work, cross layered routing protocol based on PSO (Particle swarm optimization) with adapted contention window technique is proposed. To form consistent and energy efficient routing paths, PSO algorithm uses Traffic index, Average energy load, data success rate & trust value parameters that are computed from network layer. After establishing routing paths, network's contentions are measured MAC layers for communications and contention with measured contentions and average energy loads. The trust of nodes is computed using the following constraints: group trust-provided by neighbour nodes & quality trust-computed by node QoS. Dual authentications with EnDA (enhanced dual authentication) using key management strategies for enhanced data security and integrity. ECC (Elliptical curve cryptography) and Diffie-Hellman key exchanges with bilinear maps improve security of communications. The suggested protocol when measured in terms of energy usage and secure key agreements during network's transmissions, showed satisfactory performances.

Cross Layer Design Approach to Enhance the Quality of Service in Mobile Ad Hoc Networks

The infrastructure-less and dynamic nature of mobile ad hoc networks demands a new set of networking strategies to improve the performance of quality of service (QoS). Providing QoS is a major issue in Manets. The traditional layered approach does not fit well for ad hoc networks due to high mobility and dynamic topology. This paper implements the cross layer design approach on DYMO routing protocol in Manets by using Qualnet simulator in both traditional layered approach and proposed cross layer approach. The proposed methodology uses four QoS metrics: throughput, end-to-end delay, packet delivery ratio and jitter. The experimental result reveals that QoS performance is enhanced in CLD approach for DYMO. The throughput in traditional layered approach for DYMO is 1961 b/s, whereas in the CLD approach it is 2986 b/s. Finally this paper concludes that cross layer approach significantly improves the QoS performance when compared with layered approach.

A Multimedia Cross-Layer Protocol for Underwater Acoustic Sensor Networks

Underwater multimedia acoustic sensor networks will enable new underwater applications such as multimedia coastal and tactical surveillance, undersea explorations, picture and video acquisition and classification, and disaster prevention. Because of the different application requirements, there is a need to provide differentiated-service support to delay-sensitive and delay-tolerant data traffic as well as to loss-sensitive and loss-tolerant traffic. While research on underwater communication protocol design so far has followed the traditional layered approach originally developed for wired networks, improved performance can be obtained with a cross-layer design. Hence, the objective of this work is twofold: (1) study the interactions of key underwater communication functionalities such as modulation, forward error correction, medium access control, and routing; and (2) develop a distributed cross-layer communication solution that allows multiple devices to efficiently and fairly share the bandwidth-limited high-delay underwater acoustic medium.