It is clear from the recent disaster experiences, like the Hurricane Katrina of 2005, South-Asian Tsunami of 2004, 9/11 of USA and the incessant Mumbai rain, shows  a strong need for a rapidly deployable communications network that would serve a much needed connectivity and communications among rescue workers, survivors and authority in command to restore the situation through proper resource management.

What are disasters and how to manage them?

 

Disasters are defined as an event, concentrated in time and space, which threatens a society. (Turner, 1976) Or, an extreme event as any manifestation of the earth's system (lithosphere, hydrosphere, biosphere or atmosphere) which differs substantially from the mean. Three major planks of Disasters are : (1) rapid (2) extreme event (3) profound societal impact. Disaster Management may be defined as "...a set of actions and processes designed to lessen disastrous effects before, during and after a disaster".

  [    Alexander, David. Principles of Emergency Planning and Management. Oxford University Press. New York. 2002.]

 

According to the modern concept Disaster Management is conceived as a four-phase approach in which it is based upon four distinct components: mitigation, preparedness, response and recovery.

• Mitigation involves reducing or eliminating the likelihood or the consequences of a hazard, or both. Mitigation seeks to "treat" the hazard such that it impacts society to a lesser degree.

• Preparedness involves equipping people who may be impacted by a disaster or who may be able to help those impacted with the tools to increase their chance of survival and to minimize their financial and other losses.

• Response involves taking action to reduce or eliminate the impact of disasters that have occurred or are currently occurring, in order to prevent further suffering, financial loss, or a combination of both. "Relief", a term commonly used in international disaster management, is one component of response.

• Recovery involves returning victims' lives back to a normal state following the impact of disaster consequences. The recovery phase generally begins after the immediate response has ended, and can persist for months or years thereafter.

  [  Damon P. Coppola, Introduction to International Disaster Management,   ELSEVIER. 2007.]

 

    Mitigation and Preparedness both includes three important components: public education, warning systems, risk mapping which divided into different parts with respect to the major divisions.

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Existing Disaster Management Scenario

The existing Disaster Management (DM) approach in India is centralized in nature and hierarchy-dependent. After mobilizing the whole resources into the effort of disaster management, communication between the on field personnel and the authority  are never so useful with the present methods, is always added delay and disturbance & interruption, overload of flow of information at right time and right place. To overcome the difficulties of this present scenario, it is an urgent need for a user-centric,  partly-decentralized, partly hierarchy-independent emergency communication network whose approach provides the end user to be able to share resource and information effectively.

Problems of Communication Management in Rural Areas  during Disasters

 

In rural India, the commonly used communication systems, though sparsely available, are PSTN, WLL & GSM/CDMA and most of the areas are without any infrastructure of such, added with lack of power supply to run them.

 

So, in the former case, disaster occurrence may cause complete break down of the existing communication system and the restoration of such system at that the situation becomes difficult, and takes longer time. So, an emergency communication network is required which can be rapidly deployable and flexible to work with. the demand is same for the later case, i.e., the place where no existing communication network is available.

 

Remedy

 

• A Communication Network that can be rapidly deployable

• Communication Medium should be Wireless

• Operation in Non-electrified Area

• Communication Network should be able to collect information from decentralized heterogeneous information pool

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Operation Scenario of the Communication Network

 

As in the general scenario of the disaster affected area, and for rapid deployment and operation of the proposed communication network, the affected area is divided into Three different Zones.

 

 

 

• The Central region of the zone is defined as Core Area, where communication infrastructure has been totally destroyed. The relief workers can reach this zone with great difficulty. In the Core Area, the relief workers can reach with wireless handheld devices to form Ad hoc/Infrastructure based communication network groups.

• The next zone is defined as the “non - existent communication infrastructure, but human accessible zone.” The information about the core area gathered by the said groups can be transmitted to the next zone through wireless access points with high gain antennas.

• The third zone is partly affected area where conventional communication network is partly available. In order to establish communication in partly affected area we can use WiMax technology, which conveys the information from the previous zone to the outside world. After this zone the communication network is fully available.

The proposed SDDMIN architecture advocates the concepts of wireless ad hoc/infrastructure based networking technology.

Followings are its merits,

• flexible in operation

• should operate effectively in uncertain and dynamic environments to bring together information from a variety of heterogeneous sources

• The network should provide wide area communications (WAN) and local communication within a disaster site

• The WAN can also provide a backbone for linking several hot spots at multiple separate disaster areas.

• Connectivity at local level can be provided by using a WLAN.

Based on the above analysis, the architecture of the SDDMIN has been derived as mentioned below as shown in the Figure:
 

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•   Wireless Access Points (Indoor & Outdoor)  that supports IEEE 802.11 b/g

•   8 dBi  and 15 dBi Omni-directional Antenna

•   Laptops with WLAN Activated

•   PDA

• Activity started from site  survey  and equipment study

• Gradual implementation of applications in the handheld devices and the laptops 

• Along with communication range testing and performance measurement of the Network system wireless equipments starts in the   urban areas and later in rural areas

• Different applications relating to Network Survivability Management System developed and deployed

• Risk Zone Mapping and Vulnerability Assessment has been completed for the target area

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