Thesis (M.S. in Systems Technology)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Alex Bordetsky, Brian Steckler. Includes bibliographical references (p. 69-70). Also available online.

Thesis (M.S. in Systems Technology)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Alex Bordetsky, Brian Steckler, Includes bibliographical references (p. 69-70). Also available online.

In today's society we need an emergency communication system to facilitate communication for when disaster strikes. Where the previous attempts only focused on the network communication and were missing a messaging capability between users. This thesis focused on using blockchain technologies and distributed technologies to validate if a messaging application could be built for a LoRaMesh network by using these technologies. This thesis uses the Design science method to create a design and a proof-of-concept messaging application based on the LoRaMesh protocols network constraints. The first step was to gather knowledge about Blockchain technologies and distributed technologies since these were found to be able to complement weaknesses of IoT protocols and their devices. This knowledge was then used to create a design which could then be used to create the proof-of-concept application and a controlled experiment used to validate the solution.  The controlled experiment was executed in two different iterations for a total of 430 test runs. From this controlled experiment quantitative data could be collected and then measured using the statistical analysis method linear regression analysis. The linear regression analysis was used to produce statistical data to validate the design and proof-of-concept application by controlling it against a standard p-value. The results and conclusions of this thesis contributed to new knowledge by showing how Blockchain technologies and distributed technologies can be used to complement each other. To gain a decentralized message application which can be used in an Emergency communication network based on the LoRaMesh protocols network constraints.

In September 2008, the National Weather Service (NWS) predicted that Hurricane Ike would make landfall on Galveston Island as a strong category three storm. This led the NWS to release a statement of 'certain death' if people did not adhere to the emergency evacuation messages. Millions of people fled the Texas coast. Using Hazleton and Long's (1993) taxonomy of public relations strategies, experimental methods were conducted with various evacuation messages to test emergency communication. Grunig's (1997) situational theory of publics was used to determine strategy influence. Problem recognition, constraint recognition, and level of involvement were tested. In addition, tests were conducted to measure source expertise, trust, and attitude depending on the message source. Results indicated that a national message source produced higher constraint recognition than a local message source. The national message source produced higher expertise, trust, and attitude then a local message source. The threat and punishment strategy produced the highest level of information-seeking behavior. Information-seeking behavior was the lowest when a persuasive strategy was used. Constraint recognition produced the weakest effect on information-seeking behavior. In conclusion, emergency management communicators must use the correct message strategy to have an effect on information-seeking behavior.

Most times people are unprepared to face natural disasters resulting in chaos, increased number of deaths, etc.Emergency responders need an efficiently working communication network to get in touch with the emergency services like hospitals, police, fire and rescue as well as people who are stranded. Such a network is also the need of the hour for survivors to contact their near and dear ones. One of the major barriers of communication during an emergency is the destruction of network elements. In case the communication devices survive the calamity, odds of the network getting congested are certainly high because almost everyone will be trying to use the same network resources. An important factor when dealing with emergency situations is the calls for an immediate response and an efficient Emergency Communication Systems (ECS). Currently there is a capability gap between existing ECS solutions and what we dream of achieving. Most current solutions do not meet cost or mobility constraints. An inexpensive, portable and mobile system will fulfill this capability gap. The main purpose of this research is to optimize the altitude and received signal strength of an aerial base station to provide maximum radio coverage on the ground as well as propose the best fit radio propagation channel model to carry out the experiment for the current scenario.

A call taker is the first point of contact in the emergency service system and thus the interface between the caller and ambulance dispatch. Misunderstandings in an emergency call have implications for the survival of patients. Using an applied conversation analytic approach this study examined participants’ use of conversational repair as an interactional strategy. Data included 101 calls from a South African emergency medical services call centre. The data set was comprised of two distinct subsets, namely: the 107 and public corpora. The 107 corpus (53 calls) contained calls from a general emergency call centre. The 107 caller thus served as a mediating party on behalf of the public caller. The public corpus (48 calls) comprised calls received directly from members of the public. The data subsets afforded a unique opportunity to analyse ways in which participants to an emergency call manage asymmetries of knowledge. Differential patterns of the type and purpose of repair were tracked across both data sets and similarities and differences were explored. Both data sets showed that participants’ choice of interactional strategies was customized based on an ongoing assessment of knowledge asymmetries. However, whilst knowledge asymmetries posed some constraints an overriding interactional constraint, inherent within the institutional nature of the emergency call, was a rigid adherence to routinized protocols. The call taker’s dilemma was thus identified as the management of these constraints through the frequent use of conversational repair. Although a level of responsiveness is required to glean quality information from callers, high volumes of emergency calls would not be possible without routinized protocols. However, increased orientation to routinized protocols led to a decreased orientation to responsiveness. This research therefore showed that knowledge symmetry is not necessarily more advantageous but that successful call trajectory is reliant on the call taker’s ability to maximize the collaborative nature of the interaction and effectively negotiate through the judicious use of repair and other relevant interactional strategies. This has important implications for call taker training.

在大型天然災害發生之後的黃金救援時期，災民存活率和救災效益之提昇極度仰賴於一個順暢的通訊系統。由歷年來大型災變的經驗中我們可知，行動通訊系統其實是不可靠且極為脆弱的，基地台之電力供應中斷或連接後端固定網路線路（Backhaul）之損毀都將使得通訊系統癱瘓而影響救災工作效率。 本研究提出一種新的應急通訊系統，利用原有行動通訊系統中未損毀但失去連網能力的基地台，藉由臨時供應的電力恢復其運轉，並以無線通訊設備與鄰近基地台互連建構一個臨時應急性的網路，稱為應急蜂巢式行動通訊網路（Contingency Cellular Network，CCN），供災區內手機用戶進行通訊。由於災區內部通訊的對象通常是一個特定的群組角色，而非一個特定人員，而災民與救災人員也不知彼此所在位置及聯絡的方式，因此無法以平常的撥號方式發起呼叫。本研究以CCN網路架構為基礎，設計並實作群組通訊模式，讓災區內人員以簡碼方式向任一群組發起呼叫並建立通話。 為驗證CCN群組通訊設計之可行性及效能，我們以IEEE802.11 Wi-Fi無線網路環境建置模擬系統，並以Android平台手機搭配VoIP軟體模擬手機與系統連線以進行通話。最後設計了一連串的實驗評估本模擬系統之效能。從實驗結果可知，本系統可於短時間內即時回應使用者註冊需求及完成通話連線處理；當通話數在30通以下時，Mouth-to-Ear Delay (MED) 值可維持在400ms以下，語音品質控制在一般VoIP使用者可容許的範圍之內。本實驗可作為未來改進系統功能和建置架構之參考依據。 / When stricken by a catastrophic natural disaster, the efficiency of disaster response operation is very critical to life saving. The efficiency of disaster response operation is greatly depending on communication systems. However, they were usually not dependable, including cellular networks, and often crashed due to power outage and backhaul link breakage. The failure of communication systems caused a big coordination problem to many disaster response operations. This thesis proposes a Contingency Cellular Network (CCN) by connecting isolated base stations to survival base stations using long-range wireless links to restore part of cellular network functionality. People can use their own cell phones for emergency communication in the disaster areas. CCN will be able to support many disaster response workers in the early hours of catastrophic natural disasters, thus to save many lives. Since the receiver of a phone call in a disaster area is usually a resource (agent), not a particular person, we designed a special Agency communication mode for CCN allowing CCN users to initiate a phone call to a nearby resource by dialing a designated agency number, instead of a real phone number. To verify our design, we implemented an emulated CCN system using an IEEE 802.11 Wireless LAN to mimic the CCN network and Android small phones with VoIP software to mimic user terminals. Finally, we conducted a series of experiments to evaluate the performance of the emulated system. The experimental results show that the emulated system can respond promptly to the user registration and call set-up requests. Mouth-to-Ear Delay (MED) can be effectively controlled below 400 ms when there is no more than 30 calls originated. This system may be used as reference for the future development of contingency communication networks.

This thesis is a case analysis of the nature of delays in emergency room admissions and the effects on ambulance dispatching and availability as it occurred in Southern California.

當發生大規模的地震或強烈的颱風等重大天然災害時，通訊系統常常隨著電力與交通系統的損毀而癱瘓。由歷年大型災變中多數災區內之行動通訊系統全面中斷即可印證行動通訊系統其實是極為脆弱的，然而有效運作的通訊系統卻是災情傳遞、資源調度及救災是否順利的關鍵因素。本文所探討的應急通訊系統利用倖存的連通基地台和斷訊卻沒有損毀的基地台，以無線電連接起來建構一個臨時性的通訊系統，稱為應急蜂巢式行動通訊網路(Contingency Cellular Network，CCN)。由於各地災情狀況不完全相同，CCN的建構順序必須考慮災區的輕重緩急、時間的急迫等因素依序建構。因此當CCN拓樸規劃完成後，根據CCN拓樸、各地災情嚴重程度以及拓樸中基地台間的相對距離(運輸時間)進行基地台建構排程規劃，以達到最大的總救災效益。 本文考慮各基地台所能發揮的救災效益、所需建構時間、以及運輸工具從任一基地台到另一基地台所需運輸時間，提出兩個適合CCN拓樸樹狀結構的考慮資源運輸路徑之最佳化排程模型CCNDS-AC和CCNDS-UC。CCNDS-AC限制建構順序必須從連網台往下循序建構，但CCN-UC則否。因發生突發性大型天然災害時，可容許的計算時間相當短暫，因此提出了兩個快速的啟發式演算法DS-ACG與DS-UCB，可在短時間內求出一組相當逼近於最佳解的建構排程順序，與DS-UCB相互比較。本文以電腦模擬的方式進行小規模實驗與大規模實驗評估，並且用Genetic Algorithm來比較啟發式演算法的效能。結果顯示DS-UCB明顯優於DS-ACG及Genetic Algorithm。在小規模實驗中DS-UCB可求得與最佳解的總救災效益誤差平均約0.9%的近似最佳解建構順序。而在大規模實驗下， DS-UCB與十萬個解中的最佳解─pseudo optimal solution相較，總救災效益平均高出約16.7%，而總救災時間平均約少了19.4%。 / When stricken by a large-scale disaster, the efficiency of disaster response operation is very critical to life saving. However, cellular networks were usually crashed in earthquake, typhoons or other natural disasters due to power outage or backhaul breakage. Unfortunately, the efficiency of communication system is a critical factor to the success of disaster response operation. We designed a contingency cellular network (CCN) by connecting physically intact but service-disrupted base stations together with wireless links. Since the transportation capacity may be very limited, scheduling of CCN deployment order according to the demand of disaster operation and traveling time between base stations becomes an important issue. We propose two optimization models: CCN Deployment Scheduling Antecessor Constrained Problem (CCNDS-AC) and CCN Deployment Scheduling Unconstrained Problem (CCNDS-UC), aiming to maximize the efficiency of disaster response operation. Both problems are proven to be NP Hard. We also designed two rapid heuristic algorithms, DS-ASG and DS-UCB to solve the problems respectively when it is needed in urgent. Finally, we evaluated the proposed algorithms against optimal solutions (in small cases only) as well as genetic algorithm by simulation. The experimental results show that DS-UCB outperforms all other algorithms. In small scale cases, the profit obtained by DS-UCB is only 0.9% smaller than what the optimum solution can get. In large scale cases, as compared to the pseudo optimum solution, which is the best solution among 100,000 solutions, DS-UCB outperforms pseudo optimum solutions in profit by 16.7%, and in traveling time by 19.4%, both in average.

歷年發生的大型天然災害中，行動通訊系統常常會因為道路、橋樑、電力的損毀而導致嚴重癱瘓，進而影響災後救援工作的進行，行動通訊系統其實是不可靠且極為脆弱的。為使災區能夠快速地恢復通訊，本研究提出一種應急通訊系統，利用無線通訊，將這些無連線能力的基地台連接起來，並利用存活可連至核心通訊網路的基地台，建構成為一個臨時性的通訊系統，稱為應急蜂巢式行動通訊網路(Contingency Cellular Network，CCN)，供使用者在災區內進行通訊。由於資料庫的可靠度在行動通訊網路中具有舉足輕重之地位，本論文旨在利用分散式架構提高CCN網路資料庫的可靠度，進而提高系統可靠度。我們先分析資料表的特性，並依據各資料表的特性以及資源之多寡，設計相應的分散式架構。 我們利用樹狀拓樸的簡單特性，提出三種分散式架構：(1)用於群組資料表的階層備援式架構、(2)用於HLR資料表的階層備援式架構，以及(3)用於HLR資料表的鄰近階層備援式架構。這三種架構都利用了樹狀拓樸的簡單特性，大幅簡化了資料庫的查詢及更新程序。我們以可用度及平均總成本，以評估各架構在不同的情形下之最合適架構，並觀察在各架構下，其系統可用度與平均總成本之間的關係，由結果可知，在群組資料表儲存架構中，若追求高系統可用度，可選擇高儲存密度之架構，反之，若追求較低的成本，可選擇低儲存密度之架構。而在HLR資料表儲存架構中，階層備援式的系統可用度與平均總成本比鄰近階層備援式來得高，表示階層備援式耗費較多成本，但可用度也較高，故在建置時可依實際情況來選擇合適的架構儲存。 最後，為驗證分散式資料庫架構之可行性，我們利用數部筆記型電腦及Android平台手機來建置階層備援式及鄰近階層備援式架構，並測量在此二種架構下於通話建立時所耗費的時間，從模擬結果可知，此二種架構皆可快速建置並可立即通訊，惟鄰近階層備援式所耗費的通話建立時間略長，但仍在可容許範圍之內。 / When stricken by a catastrophic natural disaster, the efficiency of disaster response operation is very critical to life saving. The efficiency of disaster response operation is greatly depending on communication systems. However, they were usually not dependable, including cellular networks, and often crashed due to power outage and backhaul link breakage. The failure of communication systems caused a big coordination problem to many disaster response operations. This thesis proposes a Contingency Cellular Network (CCN) by connecting isolated base stations to survival base stations using long-range wireless links to recover part of cellular network functionality. People can use their own cell phones for emergency communication in the disaster areas. CCN will be able to support a large number of disaster responders with limited resources in the early hours of disasters, thus to save many lives. Because the reliability of database plays a very important role in the CCN, this thesis proposes a distributed database architecture to improve the reliability of database so as the reliability of CCN. We take advantage of the simplicity of CCN tree topology to design three distributed database architectures: (1) Hierarchical Redundancy Architecture for “Group_Member ” table, (2) Hierarchical Redundancy Architecture for “HLR” table, and (3) Hierarchical Neighboring Redundancy Architecture for “HLR” table. The tree topology greatly simplified the query and update procedures. We use availability and average total cost to analytically evaluate all three architectures trying to identify the most appropriate architecture under different circumstances. Based on our evaluation results, CCN operators can choose the most appropriate architecture according to their realistic circumstances. Finally, in order to verify the feasibility of the proposed architectures, we implemented a simplified prototype using several laptops and Android mobile phones. The Hierarchical Redundancy Architecture and the Neighboring Redundancy Architecture were implemented. The results show that both architectures can be functional with reasonable performance except that Hierarchical Neighboring Redundancy Architecture may take longer time, but in a tolerable range, to setup a call.