Technology innovation has irrefutably changed communication, relationships, business, and healthcare. Telegraphy was applied to healthcare early in the 1700s and together with the telephone, began to have a significant impact by the 1900s. Some publications have outlined technology’s march into healthcare and particularly its transformation into telemedicine while others have similarly described its evolving role in psychiatric or mental health care. The use of technology to provide support to those suffering from illness was realized early and its capacity to facilitate care for the underserved, those at a distance, or those for whom care was inaccessible is captured in narratives, a few journal articles, letters, and in cartoons. Its application to mental and/or behavioral health services was initially embraced due to non-physical care dimensions. At the same time, however, psychological and human factors have propelled, transformed, and currently shape healthcare delivery via technology while the narratives of how and why people use technology inform and may direct our future work.

The Application of Technology to Health: The Evolution of Telephone to Telemedicine and Telepsychiatry: A Historical Review and Look at Human Factors

All-to-all broadcast in a network is to distribute an exclusive message from each node to every other node. It is a vital requirement in high performance computing and communication applications including enterprises operating data centers. It is also a core issue in telecommunication network where each node in the network needs to gather information about all the other nodes for efficient management of network resources. WDM optical networks act as the backbone for telecommunication networks. Wavelengths are precious resources in WDM optical networks and its usage must be limited to reduce network cost and complexity. Optical linear array finds application in LAN, WAN and MAN and its topology needs to be modified to reduce wavelength requirements and hop count. In this paper, a linear array network is modified by additionally joining alternate nodes. For such a modified linear array, the minimum wavelength number needed to support all-to-all broadcast is derived by grouping non overlapping connections on a common wavelength. The results obtained for modified linear array shows that the wavelength number needed is approximately reduced by half when compared with that of a linear array.

Wavelength Allotment for All-to-All Broadcast in WDM Optical Modified Linear Array for Reliable Communication

Multicast communication is the concurrent transmission of data from one source node to many destination nodes. It is widely deployed in high performance computing and communication networks. In this article, wide-sense nonblocking multicast communication is studied in wavelength division multiplexing networks namely modified linear array, unidirectional and bidirectional modified ring networks. The sufficient and necessary condition on the minimum wavelength number required for the network to be wide-sense nonblocking is derived for each of the above network topologies under longest link first routing technique which employs approximately half the number of hops when compared with networks without modification. An explicit wavelength allotment technique for multicast assignment is also given for each of the above network topologies.

Wide-sense nonblocking multicast in optical WDM networks

Wavelength allocation for all-to-all broadcast in bidirectional optical WDM modified ring

In this paper the problem of routing and wavelength assignment (RWA) in optical wavelength division multiplexing (WDM) networks has been addressed and a new weight based edge disjoint path (EDP) algorithm for RWA has been proposed to optimize the wavelength resources in a wavelength routed WDM networks The simulation results reveal that the network topology characteristics and link utilization factor have a significant impact on light path selection for traffic routing to minimize the required number of wavelengths The weight based RWA solution reports significant improvement in wavelength utilization in particular for large network with increase in the call request for a source destination pair

Weight Based Edge Disjoint Path Routing and Wavelength Assignment (WEDP-RWA) Algorithm for WDM Networks

Design and characterization of a modified WDM ring network – An analytical approach

In this paper, we consider the Routing and Wavelength Assignment problem in WDM optical networks. We consider the dynamic traffic and assume that in each optical fiber the number of wavelengths has fixed. In this paper, our attempt is to minimize the call connection blocking ratio using Intelligent Water Drops (IWD) Algorithm for RWA problem in an optical network. The IWD algorithm employed has modified to take into consideration the congestion and length information during the routing decision process for the optimal routes of primary lightpath establishments. Inspired by natural water drops principles, we propose a modified IWD algorithm for RWA problem in the dynamic WDM networks with improved blocking performance. Simulation results show that IWD based RWA problem can significantly achieve a lower blocking ratio performance than the traditional routing strategies.

Routing and wavelength assignment in WDM network using IWD based algorithm

This paper presents a simple generic network model to evaluate the network performance of an optical network. A probabilistic traffic model for a WDM optical network employing a ring and a star topology has been developed to investigate the call connection probability and router performances respectively. The numerical results show a huge data transmission through the router with a least dependence on the routing time up to a significant data rate.

WDM Network Topologies-A Probabilistic Model

Packet contention is a key issue in optical packet switch (OPS) networks and finds a viable solution by including optical buffering techniques incorporating fiber delay lines (FDLs) in the switch architecture. The present paper proposes a novel switch architecture for packet contention resolution in synchronous OPS network employing the packet circulation in FDLs in a synchronized manner. A mathematical model for the proposed switch architecture is developed employing packet queuing control to estimate the blocking probability for the incoming traffic. The switch performance is analyzed with a suitable contention resolution algorithm through the computer simulation. The simulation results substantiate the proposed model for the switch architecture.

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Dinesh Kumar Tyagi

Papers

Design and characterization of a modified WDM ring network – An analytical approach

Routing and wavelength assignment in WDM network using IWD based algorithm

WDM Network Topologies-A Probabilistic Model

A Novel Packet Switch Node Architecture for Contention Resolution in Synchronous Optical Packet Switched Networks

Weight Based Edge Disjoint Path Routing and Wavelength Assignment (WEDP-RWA) Algorithm for WDM Networks