A MANET Based Emergency Communication and Information System for Catastrophic Natural Disasters

Hung-chin Jang; Yao-nan Lien

A MANET Based Emergency Communication and Information System for Catastrophic Natural Disasters

2009 29th IEEE International Conference on Distributed Computing Systems Workshops, 2009

A MANET Based Emergency Communication and Information System for Catastrophic Natural Disasters Yao-Nan Lien, Hung-Chin Jang, and Tzu-Chieh Tsai Department of Computer Science, National Chengchi University Taipei, Taiwan, R.O.C. {lien, jang, ttsai}@cs.nccu.edu.tw ABSTRACT When stricken by a catastrophic natural disaster, emergency rescue operation is very critical to many lives. Many people trapped in the disastrous areas under collapsed buildings or landslides may have a large chance to survive if they are rescued in "Golden 72 Hours". People evacuated from their home jammed in highways or dome shelters need to communicate to each other for various reasons. However, communication systems were usually down due to various reasons. The loss of communication systems made the rescue operation extremely difficult. Many people died before they got a chance to be rescued. This paper analyzes the causes that paralyzed the entire communication systems in Jiji Earthquake and proposes a MANET based emergency communication and information system that can support a large number of rescue volunteers under catastrophic natural disasters. Keywords: Disaster Rescue, Mobile Computing, MANET. I. INTRODUCTION The solution presented in this paper belongs to Relevance Ring 1 because this paper proposes a special purpose MANET. Almost every year, the world is stricken by numerous catastrophic natural disasters, such as earthquake, hurricane, typhoon, tsunami, etc. When stricken by a catastrophic natural disaster, such as Jiji/Taiwan Earthquake [4], SiChuan/China Earthquake [6], or Hurricane Katrina [5], emergency rescue operation is very critical to numerous lives. Many people trapped in the disastrous areas under collapsed buildings or landslides may have a large chance to survive if they are rescued in 72 hours, referred as "Golden 72 Hours". People evacuated from their home jammed in highways or dome shelters need to communicate to each other for various reasons such as allocation of rescue and relief resource as well as reunion of family members. However, communication systems, fixed or mobile, were usually down due to various reasons. Rescue teams in each stricken area consists of few trained professional squads, army, police, fire fighters, and hundreds of thousands of disorganized volunteers. The loss of communication systems made the rescue operation extremely difficult. In Jiji Earthquake, it took ChungHwa Telecom, the largest telecommunication operator in Taiwan, 15 days of 24/7 operation to restore its mobile communication systems. Many people died before they got a chance to be rescued. Although establishing a temporary communication network to support emergency communications and networking is one of the most urgent tasks in a disastrous rescue mission, feasible technology options are very limited. We propose to use WiFi-ready notebook PCs owned by rescue volunteers themselves to construct a MANET to support such a need. Because the popularity of WiFi-ready notebook PC is very high nowadays, this solution would be highly feasible in many countries. The platform is designed and implemented in two phases. In the first phase, a simple MANET is implemented to support emergency information system. In the future second phase, we will implement an "Autonomous P2P Ad-Hoc Group Communication Systems (P2Pnet)", which is a local wireless intranet based on P2P and MANET technologies. P2Pnet is used to support the communication need under temporary serverless infrastructure-less Internet- blocked environments such as nature disastrous area, battle-field and mobile learning environments. Rescue people, voluntary or mission-specific professional, can use their own notebook PCs to construct a multi-hop ad-hoc network to form a basic wireless intranet first, then use our P2Pnet technology to form a higher level mission-specific network to support urgent communication needs such as VoIP, Push-to-Talk, and Instant Messaging, and mobile social network, etc. 2009 29th IEEE International Conference on Distributed Computing Systems Workshops 1545-0678/09 $25.00 © 2009 IEEE DOI 10.1109/ICDCSW.2009.72 412

Due to page limit, this paper will mainly focus on the system analysis and the design of the first phase platform. II. CHALLENGES AND SYSTEM ANALYSIS 2.1 Impact of Communication System Crash The impact of communication system crash to the Jiji Earthquake will be presented in this section. Many people trapped in the disastrous areas under collapsed buildings or landslides may have large chance to survive if they are rescued in 72 hours, called Golden 72 Hour. The loss of communication systems and information system created a big impact to the efficiency of rescue operation. Followings are a few painful lessons we learned from Jiji Earthquake first- handed. (One of the authors was right in a spot stricken by Jiji Earthquake to learn all the lessons first-handed.) • In a catastrophic disaster, regular rescue teams including trained professional rescue squads, police, army, and fire fighters were far from sufficient for the emergency rescue mission. A large number of volunteers must be mobilized to participate in the rescue operation. However, without a good communication system, it is very difficult to organize and coordinate rescue volunteers. • Transportation system was paralyzed not only by broken bridges and roads, but also by a large number of disorganized voluntary rescue vehicles. • A large volume of rescue and relief resources were misplaced because the assessment of disasters distribution is virtually blind and inaccurate in the early hours even days after a big quake. As a consequence, the higher accessibility a stricken spot, the easier to receive external resources. Unfortunately, reallocation of resources may not be possible because of paralyzed transportation systems. In SiChuan Earthquake, some soldiers were even dropped to the disaster areas by parachutes. It is impossible to reallocate them if they were misplaced. Misplacement of rescue and relief resources may lead to catastrophic consequence. Each stricken spot may have many vulnerable survivals, such as injured people, babies and hospital patients, whose lives are highly dependent on relief resources. Misplacement of demanded medical equipments and supplies as well as life-support resources could cost numerous lives. • Trained and skill-specific professional rescue squads were misplaced to wrong spots. For instances, a professional rescue squad specially trained and equipped for detecting survivals trapped under collapsed buildings was sent to a spot where was known having no trapped survival. • Some injured people died after being rescued from under tons of building debris because of ambulant not available or being sent to over- saturated hospitals. • Streets were blocked by the collapsed buildings so that the rescue people were divided into two isolated groups. While one group was doing sound-sensitive operation (e.g. using a high sensitive sound detector to detect any human sound under debris), the group on the other side was using heavy machinery to dig the debris. The list is much longer than what we mentioned above. In summary, the impact of communication system crash to a disaster could be catastrophic. 2.2 Causes that Crashed Communication Systems To many people's surprise, cellular mobile communication systems that were thought highly dependable in emergency were completely wiped out in many cases. Followings are parts of causes we found in Jiji Earthquake: • Base stations were crashed. • Trunks connecting base stations to MSCs were broken almost everywhere, especially broken roads and bridges. (Trunks were laid along roads and bridges). • Backup power generators were out because of fuel exhausted. • Critical hardware equipments were down because cooling tower fell down or cooling pipes were broken. • Cell phone ran out of battery and had no way to recharge because of power line failure or simply chargers not available. • Communication systems were overwhelmed by extremely huge traffic. Threatened by so many sources of failure, it requires a miracle for a cellular mobile communication system to 413

2009 29th IEEE International Conference on Distributed Computing Systems Workshops A MANET Based Emergency Communication and Information System for Catastrophic Natural Disasters Yao-Nan Lien, Hung-Chin Jang, and Tzu-Chieh Tsai Department of Computer Science, National Chengchi University Taipei, Taiwan, R.O.C. {lien, jang, ttsai}@cs.nccu.edu.tw members. However, communication systems, fixed or mobile, were usually down due to various reasons. Rescue teams in each stricken area consists of few trained professional squads, army, police, fire fighters, and hundreds of thousands of disorganized volunteers. The loss of communication systems made the rescue operation extremely difficult. In Jiji Earthquake, it took ChungHwa Telecom, the largest telecommunication operator in Taiwan, 15 days of 24/7 operation to restore its mobile communication systems. Many people died before they got a chance to be rescued. ABSTRACT When stricken by a catastrophic natural disaster, emergency rescue operation is very critical to many lives. Many people trapped in the disastrous areas under collapsed buildings or landslides may have a large chance to survive if they are rescued in "Golden 72 Hours". People evacuated from their home jammed in highways or dome shelters need to communicate to each other for various reasons. However, communication systems were usually down due to various reasons. The loss of communication systems made the rescue operation extremely difficult. Many people died before they got a chance to be rescued. This paper analyzes the causes that paralyzed the entire communication systems in Jiji Earthquake and proposes a MANET based emergency communication and information system that can support a large number of rescue volunteers under catastrophic natural disasters. Although establishing a temporary communication network to support emergency communications and networking is one of the most urgent tasks in a disastrous rescue mission, feasible technology options are very limited. We propose to use WiFi-ready notebook PCs owned by rescue volunteers themselves to construct a MANET to support such a need. Because the popularity of WiFi-ready notebook PC is very high nowadays, this solution would be highly feasible in many countries. Keywords: Disaster Rescue, Mobile Computing, MANET. The platform is designed and implemented in two phases. In the first phase, a simple MANET is implemented to support emergency information system. In the future second phase, we will implement an "Autonomous P2P Ad-Hoc Group Communication Systems (P2Pnet)", which is a local wireless intranet based on P2P and MANET technologies. P2Pnet is used to support the communication need under temporary serverless infrastructure-less Internetblocked environments such as nature disastrous area, battle-field and mobile learning environments. I. INTRODUCTION The solution presented in this paper belongs to Relevance Ring 1 because this paper proposes a special purpose MANET. Almost every year, the world is stricken by numerous catastrophic natural disasters, such as earthquake, hurricane, typhoon, tsunami, etc. When stricken by a catastrophic natural disaster, such as Jiji/Taiwan Earthquake [4], SiChuan/China Earthquake [6], or Hurricane Katrina [5], emergency rescue operation is very critical to numerous lives. Many people trapped in the disastrous areas under collapsed buildings or landslides may have a large chance to survive if they are rescued in 72 hours, referred as "Golden 72 Hours". People evacuated from their home jammed in highways or dome shelters need to communicate to each other for various reasons such as allocation of rescue and relief resource as well as reunion of family 1545-0678/09 $25.00 © 2009 IEEE DOI 10.1109/ICDCSW.2009.72 Rescue people, voluntary or mission-specific professional, can use their own notebook PCs to construct a multi-hop ad-hoc network to form a basic wireless intranet first, then use our P2Pnet technology to form a higher level mission-specific network to support urgent communication needs such as VoIP, Push-to-Talk, and Instant Messaging, and mobile social network, etc. 412 Due to page limit, this paper will mainly focus on the system analysis and the design of the first phase platform. • II. CHALLENGES AND SYSTEM ANALYSIS 2.1 Impact of Communication System Crash The impact of communication system crash to the Jiji Earthquake will be presented in this section. Many people trapped in the disastrous areas under collapsed buildings or landslides may have large chance to survive if they are rescued in 72 hours, called Golden 72 Hour. The loss of communication systems and information system created a big impact to the efficiency of rescue operation. Followings are a few painful lessons we learned from Jiji Earthquake firsthanded. (One of the authors was right in a spot stricken by Jiji Earthquake to learn all the lessons first-handed.) • • • • • medical equipments and supplies as well as life-support resources could cost numerous lives. Trained and skill-specific professional rescue squads were misplaced to wrong spots. For instances, a professional rescue squad specially trained and equipped for detecting survivals trapped under collapsed buildings was sent to a spot where was known having no trapped survival. Some injured people died after being rescued from under tons of building debris because of ambulant not available or being sent to oversaturated hospitals. Streets were blocked by the collapsed buildings so that the rescue people were divided into two isolated groups. While one group was doing sound-sensitive operation (e.g. using a high sensitive sound detector to detect any human sound under debris), the group on the other side was using heavy machinery to dig the debris. The list is much longer than what we mentioned above. In summary, the impact of communication system crash to a disaster could be catastrophic. In a catastrophic disaster, regular rescue teams including trained professional rescue squads, police, army, and fire fighters were far from sufficient for the emergency rescue mission. A large number of volunteers must be mobilized to participate in the rescue operation. However, without a good communication system, it is very difficult to organize and coordinate rescue volunteers. Transportation system was paralyzed not only by broken bridges and roads, but also by a large number of disorganized voluntary rescue vehicles. A large volume of rescue and relief resources were misplaced because the assessment of disasters distribution is virtually blind and inaccurate in the early hours even days after a big quake. As a consequence, the higher accessibility a stricken spot, the easier to receive external resources. Unfortunately, reallocation of resources may not be possible because of paralyzed transportation systems. In SiChuan Earthquake, some soldiers were even dropped to the disaster areas by parachutes. It is impossible to reallocate them if they were misplaced. Misplacement of rescue and relief resources may lead to catastrophic consequence. Each stricken spot may have many vulnerable survivals, such as injured people, babies and hospital patients, whose lives are highly dependent on relief resources. Misplacement of demanded 2.2 Causes that Crashed Communication Systems To many people's surprise, cellular mobile communication systems that were thought highly dependable in emergency were completely wiped out in many cases. Followings are parts of causes we found in Jiji Earthquake: • • • • • • Base stations were crashed. Trunks connecting base stations to MSCs were broken almost everywhere, especially broken roads and bridges. (Trunks were laid along roads and bridges). Backup power generators were out because of fuel exhausted. Critical hardware equipments were down because cooling tower fell down or cooling pipes were broken. Cell phone ran out of battery and had no way to recharge because of power line failure or simply chargers not available. Communication systems were overwhelmed by extremely huge traffic. Threatened by so many sources of failure, it requires a miracle for a cellular mobile communication system to 413 recommendation is to trade functionality for simplicity, developing basic functions only and giving up most advanced features. survive in such a catastrophic disaster, even for a robust system with 99.999% reliability. Even if there is a miracle, volunteers do not know each other and do not have time to remember large amount of phone numbers. Thus, a survived cellular communication system provides not too much help either. Performance Requirements • 2.3 Environmental Constraints and System Requirements • • • • Following are the constraints and requirements for an emergency communication system that can support a voluntary rescue operation for a catastrophic disaster. Environmental Constraints for a Disastrous Spot • • • • • • 2.4 Available Options Communication Systems Outgoing link (Internet) is either not available or very limited. Server is probably not available. All Internet based services, such as Skype, are not available, because of no Internet access. There is a very stringent time constraint that volunteers are not able to use those devices that have a complicated user interface. In other words, user interface must be very simple. WiFi-ready notebook PCs are assumed very popular. Portable power generators are assumed available. • • • • • of Emergency There are few options for emergency communication systems. • Walkie-Talkie Perhaps Walkie-Talkie is the most convenient and reliable communication system for emergency. However, the popularity of Walkie-Talkie in many countries is far less than notebook PCs. Although regular rescue squads may already equipped with similar equipments, most volunteers may not have such equipments. Even if Walkie-Talkie handsets are widely available, we still need a data network that can support information services such as resource allocations. Functional Requirements • provide tolerable QoS for multimedia communications maintain minimum level of throughput give precedent to QoS over throughput provide class-based priority services provide high member coverage for group communications User interface must be simple, easy to learn, and fool-proof. Devices do not need complicated setup procedure. Devices must be fault-tolerant such that misusage will not crash a device. The system must support broadcast based multimedia communications, while unicast communication mode is optional. Only basic functions are required, advanced features are optional. The system must not demand high power, must be able to recharge using a portable power generator. • Emergency Systems Mobile Communication Various equipment vendors are offering emergency mobile communication systems [7,8]. Specially designed systems are expensive and offer only limited number of handsets. It is prohibitively expensive to deploy sufficient capacity for a catastrophic disaster as big as mentioned cases. In summary, the capacity of current speciallydesigned emergency communication systems may be able to support regular rescue squads, but are far from sufficient for large amount of volunteers. Without plenty of resources and time, it is not easy to develop a system that meets all the requirements listed above, especially the first three. User-friendly and robustness cost a fortune to achieve. Therefore, our Most cellular operators have emergency cellular systems that use satellite links as 414 backhauls and can be deployed to a demanded area in a few hours. However, there are two problems. First, cellular operators may not have sufficient number of such systems for catastrophic disaster. Secondly, as mentioned in Section 2.2, volunteers do not know each other and have no time to memorize (or keep in handset) many phone numbers and may not have handset chargers in hand. • • MANET based P2Pnet We propose to use WiFi-ready notebooks to construct a MANET based group communication system to support emergency communication and information network, called P2Pnet. In recent years, WiFi-ready notebook PC that can last for several hours is becoming a very popular and universally compatible device in many areas. When stricken by a natural disaster, survivals and volunteers can use their own notebook PCs to construct a P2Pnet. Using P2P communication technologies, a P2Pnet is able to support Walkie-Talkie-like communication, Push-to-Talk, VoIP, and network information systems for emergency usage. Compared with other options, no extra hardware cost is needed. • communications and is the easiest network to construct. This is designed for the usage in the early hour of disasters when all the organizational effort is not in place yet. Uncontrolled K-Hop Group Communication Network (UKNet) Each node can broadcast data to neighboring nodes in K-hop distance. No authorization will be enforced. This mode can support long range Walkie-Talkie-like communications. This is also designed for the usage in the early hour of disaster when all the organizational effort is not in place yet. However, it is a little more complicated than U1net so that it requires more effort to construct. Controlled K-Hop Group Communication Network (CKNet) This is a more advanced mode and can support unicast type services such as VoIP. It requires more organizational effort, such as assigning unique IP addresses, to construct such a network mode and may not be easy to construct in the early hours of a disaster. III. MANET Based P2Pnet 3.1 System Architecture P2Pnet is a serverless peer-to-peer communication network based on MANET to support temporary group communication and information network. As depicted in Fig. 1, some nodes may have satellite communication capability performing gateway functions so that all other nodes can access Internet through gateways if they are available. On top of MANET, there is a layer of peer-to-peer communication service to support higher level services such as Walkie-Talkie, Push-to-Talk, and VoIP communications. Three basic communication modes are supported as followings: Fig. 1 Architecture of P2Pnet 3.2 Feasibility Assessment The availability of compatible notebook PCs and power supplies are the two most critical feasibility factors. Availability of Notebook PCs • Uncontrolled Single-Hop Group Communication Network (U1Net) Each node can broadcast data to neighboring nodes in one-hop distance. No authorization will be enforced. This mode can support short range Walkie-Talkie-like In many countries, highly compatible notebook PCs equipped with 802.11 WLAN capability running TCP/IP network protocol is getting more and more popular. Starting from 2008, inexpensive mininotebook PC has been very successful and has no sign 415 to stop its momentum yet. Proliferattion of computer literacy to the low income world in thhe near future has been in our vision. We can imagine thhat constructing a P2Pnet for emergency communicatioon is completely feasible in many areas of the worrld. It would be foolish to ignore such a convenientt communication tool. catastrophic earthquake. The ER model is shown in Fig. 2 Availability of Power Supplies Electricity will be most likely knockked out even in a small disaster such as a snow storm. Power generator has long been a typical equippment in most contingency plans. In some areas ssuch as Taiwan, portable generators are very popular bbecause of a large population of flea-market-style eveninng markets. On the other hand, the battery life haas been extended from 2 hours to 8 hours. As mini-nootebook PC, that consumes less power than regular nootebook PCs, gets its momentum recently, we can annticipate that the chance of having many long-life nnotebook PCs in many areas is very high. Compared w with other heavy machinery, the fuel consumed by P P2Pnet is only a small fraction of total fuel consumptioon. Fig. 2 ER Diagram off RISED RISED provides seismic related information to assist disaster assessment. Useful information includes seismic fault locations, populaation distributions, building characteristics, and quak ke history. Together with collected real-time disasster statistics, the information system can supportt a more accurate disaster assessment for a better diistribution of rescue and relief resources. The details of o the system can be found in [2]. 3.3 System Developments P2Pnet has been developed in two pphases. The first phase is to develop a simple MANET T. Only simplified information service is supported. In tthe second phase, a more advanced system will be consttructed. It will be able to support broadcast-based annd unicast-based multimedia communications such aas Walkie-Talkie and VoIP conference. 4.2 A Study of Mobile Learnin ng This research studies the effeectiveness and the behavior of a group of English leaarning students over a mobile learning platform (NCC CU-MLP) developed in National Chengchi University (N NCCU). The goal of NCCU-MLP is to improve studentts' English ability as well as to update teachers' teaching using the latest technology. It offers a multimeedia based English learning environment as well as Push-to-Talk (PTT) and whiteboard capability for grou up communications. The technology aspects of the exp periment results are summarized in this section. IV. EXPERIMENT TS On top of the first phase platform, a simple MANET, we designed a Rescue Information System for Earthquake Disaster (RISED) [2, 3] and a mobile learning platform over P2Pnet, NCCU U-MLP. We also conducted a research based on NCC CU-MLP to study the effectiveness and the behaviorr of a group of English learning students and to test our P2Pnet concept [1]. (It is unrealistic to test ouur design in a real catastrophic earthquake.) • 4.1 Rescue Information System ffor Earthquake Disaster • RISED is designed to supportt resource and information management for the resccue mission in a 416 y of wireless radio The transmission quality signals is highly depend dent on the weather conditions, especially on n rainy days. As a consequence, the stability y of mobile network connection is lower than fixed f networks.. The software system in a mobile computing environment is much more complicated than its counter part on fixed d networks. Thus, it needs more effort to make m the software • • 6. system robust. Our recommendation is to trade functionality for simplicity. Compared with voice communication tool, such as PTT, whiteboard is even less ideal for group communication. First, people are used to talk than to write. Secondly, voice communication is more convenient than hand-writing. Users prefer full-duplex conversation mode (such as VoIP) to half-duplex mode (such as PTT). However, it remains a great technical challenge to offer group voice communication in full-duplex conversational mode under limited bandwidth. 7. 8. V. CONCLUDING REMARKS The most important lessons we learned from numerous disasters are that mobile communication system is vulnerable and the loss of communication system may have a catastrophic consequence. This paper analyzes the causes that paralyzed the entire communication systems in Jiji Earthquake and proposes a P2Pnet that uses notebook PCs to construct a MANET based emergency communication and information system. Brief system requirements and system design are presented. A prototype of Disastrous Earthquake Rescue Information System is presented. Finally, a P2Pnet prototype was tested in an English mobile learning class. The technical aspects of experiment results are presented. REFERENCES 1. 2. 3. 4. 5. Pei-Chun Che, Han-Yi Lin, Hung-Chin Jang, YaoNan Lien and Tzu-Chieh Tsai, 2004, "A Study of English Mobile Learning Applications in National Chengchi University", Submitted to Journal of Distant Learning Technology. Hung-Chin Jang and Tzu-Chieh Tsai, "Mobile Information Management System For Disastrous Earthquake Emergency," FET Labs Journal, Vol. 3, 2001, pp. 64-68. Hung-Chin Jang, Yao-Nan Lien and Tsu-Chieh Tsai, "Rescue Information System for Earthquake Disasters Based on MANET Emergency Communication Platform", To appear in the International Workshop on Advanced Topics in Mobile Computing for Emergency Management: Communication and Computing Platforms, June, 2009. Jiji Earthquake, http://jiji.ncree.gov.tw/, retrieved Dec. 19, 2008. Hurricane Katrina, http://en.wikipedia.org/wiki/Hurricane_Katrina, retrieved Dec. 19, 2008. 417 SiChuan Earthquake, http://en.wikipedia.org/wiki/2008_Sichuan_earthq uake, retrieved Dec. 19, 2008. http://www.ideal-ist.net/Countries/DE/PS-DE-486, retrieved Dec. 19, 2008. http://www.gothamgazette.com/article/20040524/ 19/990, retrieved Dec. 19, 2008.

Traditionally, emergency response is in large part the role and responsibility of formal organizations. Advances in information technology enable amateurs or concerned publics to play a meaningful role in emergency response. Indeed, in recent catastrophic disasters or crises such as the 2010 Haiti earthquake and the 2011 Japan earthquake and nuclear crisis, participatory online groups of the general public from both across the globe and the affected areas made significant contributions to the effective response through crowdsourcing vital information and assisting with the allocation of needed resources. Thus, a more integrative lens is needed to understand the responses of various actors to catastrophic crises or disasters by taking into account not only formal organizations with legal responsibilities, but also volunteer-based, participatory groups who actively participate in emergency response. In this dissertation, I first developed an “event-driven” lens for integrating both formal and volunteer-based, participatory emergency responses on the basis of a comprehensive literature review (chapter 1). Then I conducted a deeper analysis of one aspect of the event-driven lens: relationships between participatory online groups and formal organizations in crisis or disaster situations. Specifically, I explored organizational and technical determinants and outcomes of forming such relationships (chapter 2). As a consequence, I found out three determinants (resource dependence, shared understanding, and information technology) and two outcomes (inter-organizational alignment and the effectiveness of coordinated emergency response) of the relationship between participatory online groups and formal organizations and suggested seven hypotheses. Furthermore, I empirically tested these hypotheses, focusing on the 2015 Nepal earthquake case (chapter 3). As a result, I found ii empirical evidence that supports that shared understanding and information technology improve the development of the relationship between participatory online groups and formal organizations. Moreover, research findings support that the development of the relationship enhances inter-organizational coordination. Lastly, I provide implications for future research (chapter 4). This dissertation is expected to contribute to bridging the disconnect between the emergency management literature and the crisis informatics literature. The theoretical insight from inter-organizational relations (IOR) theory provides another contribution.

https://www.ijert.org/ballooned-skymesh-for-network-providing-and-sensing-disaster-areas https://www.ijert.org/research/ballooned-skymesh-for-network-providing-and-sensing-disaster-areas-IJERTV4IS030892.pdf As emergency communication systems for the large scale disaster, a wireless network using balloons, SKYMESH, was proposed so far. In this paper, a renewable energy based wireless ballooned network is designed to insure communication means to grasp information in disaster areas. By combining multiple ballooned wireless network nodes, a large adhoc network is automatically organized in the sky on the disaster area and can cover shelters or interrupted communication area as urgent communication means. SKYMESH is an emergency communication system for large scale disaster. As emergency communication systems for the large scale disaster of wireless network using balloons, a network construction method for SKYMESH is proposed. The proposed network construction method is implemented, and its performance is evaluated Keywords: Ad hoc network, Wide Area Disaster Information Network, Emergency communication, Ballooned Network I.INTRODUCTION Recently natural disasters such as earthquake, seismic sea wave, typhoon, hurricane in addition to annual disaster have frequently happened at many places around the world. When disaster occurs, information networks infrastructure performs very important role as the resident's communication means. However, once a disaster occurred, failures of network equipments, cutoff of communication lines and traffic congestion cannot be avoided. More reliable and robust network environment is required even though the serious damaged by disaster occurred. As a solution of this problem, a wireless network using balloons, SKYMESH, was proposed as emergency communication systems [1]. So far, we have developed effective Wide area Disaster information Network (WDN) using Internet over the combination of both wired and wireless network[2][3]. In this information network, two important functions including resident safety information system and bidirectional video communication system between evacuation places and disaster information centre are provided [4][5][6]. However, in this WDN, system failure of network and computing facilities by disaster were not considered. In the past work, communication quality was investigated by experiment [7], [8], and remote monitoring system using SKYMESH was proposed [9], but it is hardly discussed how to construct SKYMESH networks. In the conventional mesh networks, the network construction and management methods were discussed in [10], [11]. However, it is not a good choice to use these methods for SKYMESH because SKYMESH has particular characteristics, which are not seen in the conventional mesh networks. In this paper, a ballooned wireless network is proposed to promptly insure communication means to grasp the information with disaster area, resident's safety and relief goods on the occurrence of disaster. By combining multiple ballooned wireless network nodes, a large adhoc network is automatically organized in the sky on the disaster area and can cover shelters or interrupted communication area as urgent communication means. The Structure consists of balloon nodes, terrestrial nodes and user terminals are termed as SKYMESH. SKYMESH is an emergency communication system for large scale disaster. Then not only specialists but also people who are out of touch with network technology can construct it. SKYMESH has a peculiar characteristic, which derives from network components such as balloon nodes and terrestrial nodes. In the followings, the system structure is described in section 2. Network Placement Scheme is explained in section 3. Network Construction Method is explained in section 4. The proposed network construction method is implemented, and its performance is evaluated by experiments in 5. Finally concluding remarks and future works are summarized in section 6.

On August 25, 2017, Hurricane Harvey made landfall near Rockport, Texas as a Category 4 hurricane with maximum sustained winds of approximately 200 km/hour. Harvey caused severe damages in coastal Texas due to extreme winds and storm surge, but will go down in history for record-setting rainfall totals and flood-related damages. Across large portions of southeast Texas, rainfall totals during the six-day period between August 25 and 31, 2017 were amongst the highest ever recorded, causing flooding at an unprecedented scale. More than 100,000 residential properties are estimated to have been affected in southeast Texas. It is likely that Harvey will rank among the costliest storms in U.S. history.In the wake of Hurricane Harvey, Delft University of Technology has initiated a Harvey Research Team to undertake a coordinated multidisciplinary investigation of the events with a focus on the greater Houston area. This ‘fact-finding’ research is based on information available from public sources during and in the first weeks after the event. Results are therefore preliminary, but aim to provide insight into lessons that can be learned for both Texas and the Netherlands. As part of the investigations, a hackathon with more than 80 participants was organized to collect and analyze available public information.Houston was especially hard hit by flooding. During the event, all 22 watersheds in the greater Houston area experienced flooding. Many of Houston’s creeks and bayous exceeded their channel capacities, reaching water levels never before recorded. Across large portions of Harris County, rainfall totals exceeded the 1000-year return period. In addition, the water from the two reservoirs protecting downtown Houston (Addicks and Barker) were opened on August 28 to prevent catastrophic damages to the dams and further flooding in upstream communities. The releases exacerbated flooding in the areas downstream of the dams and an estimated 4,000 homes in neighborhoods downstream of the dams were impacted by flooding. The consequences of the event in the greater Houston area have been characterized in terms of economic damages, loss of life and impacts on critical infrastructure, airports and industry. In total, more than 100,000 homes were affected more than 70 fatalities were reported in the greater Houston area. The event highlighted the vulnerability of industrial facilities, as several cascading impacts (releases of toxic materials and explosions) were reported. Emergency response has been assessed. No large-scale mandatory evacuation was ordered before or during Harvey. However, it appeared that several local evacuations were ordered for areas with specific risks and circumstances. During the event, many people were trapped by rising waters necessitating a major rescue operation. In total, more than 10,000 rescues were made by professional and volunteer rescuers. Social media played an important role during the event and recovery, as an additional source of information, to inform emergency managers and as a means to organize community response e.g. for clean-up. Also, messages were conveyed through social media, e.g. a report of a levee breach that appeared to be incorrect afterwards.Major flooding is a problem that has multiple causes from both physical and social origin. Based on the investigations, recommendations for future research and lessons for flood management have been formulated. A better understanding of the issues studied in this report is expected to contribute to a knowledge basis for further in-depth investigations and future directions for flood risk reduction. Data collection and Report production funded by DIMI and DSysSpecial Case 'Houston Galveston Bay Region, Texas, USA'Project 'Harvey hackathon' and follow-up research.

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A MANET Based Emergency Communication and Information System for Catastrophic Natural Disasters