Current Search: Protocols (x)
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Title
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EXTENDING DISTRIBUTED TEMPORAL PROTOCOL LOGIC TO A PROOF BASED FRAMEWORK FOR AUTHENTICATION PROTOCOLS.
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Creator
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Muhammad, Shahabuddin, Guha, Ratan, University of Central Florida
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Abstract / Description
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Running critical applications, such as e-commerce, in a distributed environment requires assurance of the identities of the participants communicating with each other. Providing such assurance in a distributed environment is a difficult task. The goal of a security protocol is to overcome the vulnerabilities of a distributed environment by providing a secure way to disseminate critical information into the network. However, designing a security protocol is itself an error-prone process. In...
Show moreRunning critical applications, such as e-commerce, in a distributed environment requires assurance of the identities of the participants communicating with each other. Providing such assurance in a distributed environment is a difficult task. The goal of a security protocol is to overcome the vulnerabilities of a distributed environment by providing a secure way to disseminate critical information into the network. However, designing a security protocol is itself an error-prone process. In addition to employing an authentication protocol, one also needs to make sure that the protocol successfully achieves its authentication goals. The Distributed Temporal Protocol Logic (DTPL) provides a language for formalizing both local and global properties of distributed communicating processes. The DTPL can be effectively applied to security protocol analysis as a model checker. Although, a model checker can determine flaws in a security protocol, it can not provide proof of the security properties of a protocol. In this research, we extend the DTPL language and construct a set of axioms by transforming the unified framework of SVO logic into DTPL. This results into a deductive style proof-based framework for the verification of authentication protocols. The proposed framework represents authentication protocols and concisely proves their security properties. We formalize various features essential for achieving authentication, such as message freshness, key association, and source association in our framework. Since analyzing security protocols greatly depends upon associating a received message to its source, we separately analyze the source association axioms, translate them into our framework, and extend the idea for public-key protocols. Developing a proof-based framework in temporal logic gives us another verification tool in addition to the existing model checker. A security property of a protocol can either be verified using our approach, or a design flaw can be identified using the model checker. In this way, we can analyze a security protocol from both perspectives while benefiting from the representation of distributed temporal protocol logic. A challenge-response strategy provides a higher level of abstraction for authentication protocols. Here, we also develop a set of formulae using the challenge-response strategy to analyze a protocol at an abstract level. This abstraction has been adapted from the authentication tests of the graph-theoretic approach of strand space method. First, we represent a protocol in logic and then use the challenge-response strategy to develop authentication tests. These tests help us find the possibility of attacks on authentication protocols by investigating the originator of its received messages. Identifying the unintended originator of a received message indicates the existence of possible flaws in a protocol. We have applied our strategy on several well-known protocols and have successfully identified the attacks.
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Date Issued
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2007
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Identifier
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CFE0001799, ucf:47281
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0001799
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Title
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THE EFFECTS OF SEPSIS MANAGEMENT PROTOCOLS ON TIME TO ANTIBIOTIC ADMINISTRATION IN THE EMERGENCY DEPARTMENT.
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Creator
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Lorch, Margaret K, Bourgault, Annette, University of Central Florida
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Abstract / Description
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Sepsis is one of the leading causes of death in U.S. hospitals, resulting from organ dysfunction caused by an inappropriate inflammatory reaction to an infection. Timely treatment with empiric antibiotics in the emergency department is crucial to facilitate positive patient outcomes. The Surviving Sepsis Campaign (SSC) recommends initiating empiric antibiotic therapy within one hour of presentation to the emergency department. Some emergency departments have implemented sepsis management...
Show moreSepsis is one of the leading causes of death in U.S. hospitals, resulting from organ dysfunction caused by an inappropriate inflammatory reaction to an infection. Timely treatment with empiric antibiotics in the emergency department is crucial to facilitate positive patient outcomes. The Surviving Sepsis Campaign (SSC) recommends initiating empiric antibiotic therapy within one hour of presentation to the emergency department. Some emergency departments have implemented sepsis management protocols to guide care and ensure timely treatment. The purpose of this study is to determine the effect of a formal sepsis protocol in the emergency department on the time to antibiotic administration. A literature review was conducted using CINAHL, Cochrane Database, Health Source: Nursing/Academic Edition, and MEDLINE. Results from one systematic review, eight quasi-experimental studies, and four quality improvement projects suggested that implementation of a sepsis management protocol in an emergency department may decrease the time to antibiotic administration. ([less than] 10 = spell out) Eleven of the 13 articles reported decreased time to antibiotic administration by as much as 8-193 minutes compared to pre-protocol. One study met the SSC goal of 1 hour and reported a median administration time of 17 minutes. Time to antibiotics was influenced by protocols based on published sepsis guidelines, inclusion of antibiotic guidelines, nurse-initiated treatment, and education for emergency clinicians regarding sepsis management. Emergency departments should implement sepsis protocols adapted to their local institution to decrease time to antibiotic administration and reduce mortality of sepsis patients. Further research on how sepsis protocols affect antibiotic administration time is needed.
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Date Issued
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2018
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Identifier
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CFH2000341, ucf:45734
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFH2000341
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Title
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MEDIUM ACCESS CONTROL PROTOCOLS AND ROUTING ALGORITHMS FOR WIRELESS SENSOR NETWORKS.
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Creator
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Bag, Anirban, Bassiouni, Mostafa, University of Central Florida
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Abstract / Description
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In recent years, the development of a large variety of mobile computing devices has led to wide scale deployment and use of wireless ad hoc and sensor networks. Wireless Sensor Networks consist of battery powered, tiny and cheap "motes", having sensing and wireless communication capabilities. Although wireless motes have limited battery power, communication and computation capabilities, the range of their application is vast. In the first part of the dissertation, we have addressed the...
Show moreIn recent years, the development of a large variety of mobile computing devices has led to wide scale deployment and use of wireless ad hoc and sensor networks. Wireless Sensor Networks consist of battery powered, tiny and cheap "motes", having sensing and wireless communication capabilities. Although wireless motes have limited battery power, communication and computation capabilities, the range of their application is vast. In the first part of the dissertation, we have addressed the specific application of Biomedical Sensor Networks. To solve the problem of data routing in these networks, we have proposed the Adaptive Least Temperature Routing (ALTR) algorithm that reduces the average temperature rise of the nodes in the in-vivo network while routing data efficiently. For delay sensitive biomedical applications, we proposed the Hotspot Preventing Routing (HPR) algorithm which avoids the formation of hotspots (regions having very high temperature) in the network. HPR forwards the packets using the shortest path, bypassing the regions of high temperature and thus significantly reduces the average packet delivery delay, making it suitable for real-time applications of in-vivo networks. We also proposed another routing algorithm suitable for being used in a network of id-less biomedical sensor nodes, namely Routing Algorithm for networks of homogeneous and Id-less biomedical sensor Nodes (RAIN). Finally we developed Biocomm, a cross-layer MAC and Routing protocol co-design for Biomedical Sensor Networks, which optimizes the overall performance of an in-vivo network through cross-layer interactions. We performed extensive simulations to show that the proposed Biocomm protocol performs much better than the other existing MAC and Routing protocols in terms of preventing the formation of hotspots, reducing energy consumption of nodes and preventing network congestion when used in an in-vivo network. In the second part of the dissertation, we have addressed the problems of habitat-monitoring sensor networks, broadcast algorithms for sensor networks and the congestion problem in sensor networks as well as one non-sensor network application, namely, on-chip communication networks. Specifically, we have proposed a variation of HPR algorithm, called Hotspot Preventing Adaptive Routing (HPAR) algorithm, for efficient data routing in Networks On-Chip catering to their specific hotspot prevention issues. A protocol similar to ALTR has been shown to perform well in a sensor network deployed for habitat monitoring. We developed a reliable, low overhead broadcast algorithm for sensor networks namely Topology Adaptive Gossip (TAG) algorithm. To reduce the congestion problem in Wireless Sensor Networks, we proposed a tunable cross-layer Congestion Reducing Medium Access Control (CRMAC) protocol that utilizes buffer status information from the Network layer to give prioritized medium access to congested nodes in the MAC layer and thus preventing congestion and packet drops. CRMAC can also be easily tuned to satisfy different application-specific performance requirements. With the help of extensive simulation results we have shown how CRMAC can be adapted to perform well in different applications of Sensor Network like Emergency Situation that requires a high network throughput and low packet delivery latency or Long-term Monitoring application requiring energy conservation.
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Date Issued
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2007
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Identifier
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CFE0001915, ucf:47480
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0001915
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Title
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ACCESS GAMES: A GAME THEORETIC FRAMEWORK FOR FAIR BANDWIDTH SHARING IN DISTRIBUTED SYSTEMS.
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Creator
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Rakshit, Sudipta, Guha, Ratan, University of Central Florida
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Abstract / Description
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In this dissertation, the central objective is to achieve fairness in bandwidth sharing amongst selfish users in a distributed system. Because of the inherent contention-based nature of the distributed medium access and the selfishness of the users, the distributed medium access is modeled as a non-cooperative game; designated as the Access Game. A p-CSMA type medium access scenario is proposed for all the users. Therefore, in the Access Game, each user has two actions to choose from: ...
Show moreIn this dissertation, the central objective is to achieve fairness in bandwidth sharing amongst selfish users in a distributed system. Because of the inherent contention-based nature of the distributed medium access and the selfishness of the users, the distributed medium access is modeled as a non-cooperative game; designated as the Access Game. A p-CSMA type medium access scenario is proposed for all the users. Therefore, in the Access Game, each user has two actions to choose from: "transmit" and "wait". The outcome of the Access Game and payoffs to each user depends on the actions taken by all the users. Further, the utility function of each user is constructed as a function of both Quality of Service (QoS) and Battery Power (BP). Various scenarios involving the relative importance of QoS and BP are considered. It is observed that, in general the Nash Equilibrium of the Access Game does not result into fairness. Therefore, Constrained Nash Equilibrium is proposed as a solution. The advantage of Constrained Nash Equilibrium is that it can be predicated on the fairness conditions and the solution will be guaranteed to result in fair sharing of bandwidth. However, Constrained Nash Equilibrium is that it is not self-enforcing. Therefore, two mechanisms are proposed to design the Access Game in such a way that in each case the Nash Equilibrium of the Access Game satisfies fairness and maximizes throughput. Hence, with any of these mechanisms the solution of the Access Game becomes self-enforcing.
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Date Issued
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2005
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Identifier
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CFE0000700, ucf:46603
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0000700
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Title
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Novice Science Teachers' Thinking About the Purpose of Teachers' Questions.
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Creator
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Crittenden, Gwyndolyn, Jeanpierre, Bobby, University of Central Florida
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Abstract / Description
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Effective teacher questioning during whole group instruction remains an important pedagogy in science education, especially the importance of helping novice teachers to guide student thinking using effective questions. This study examined how novice secondary science teachers' understand the relationship between student thinking and teacher questioning. The sample was seven novice secondary science teachers' enrolled in the University of Central Florida's job embedded Resident Teacher...
Show moreEffective teacher questioning during whole group instruction remains an important pedagogy in science education, especially the importance of helping novice teachers to guide student thinking using effective questions. This study examined how novice secondary science teachers' understand the relationship between student thinking and teacher questioning. The sample was seven novice secondary science teachers' enrolled in the University of Central Florida's job embedded Resident Teacher Professional Preparation Program (RTP3). All participants received instruction and guided practice with the use of questions to elicit, probe, and challenge student ideas in the secondary science pedagogy class. Participants completed a questionnaire describing their teaching experience and science content knowledge. The primary data were think aloud interviews describing their thinking while observing two science instruction videos. Protocols, critical incident interviews, and field notes were transcribed and coded for analysis. Descriptive codes identified properly classified question types and the purpose or value of questions, student thinking, and student reaction to teacher questions. Pattern codes identified student engagement, feedback, wait time, and communication patterns. The think aloud used in this study provided insight into what the participants were thinking about the purposes of questions to elicit, probe, and challenge student ideas and gave insight into the decision process. Evidence from the protocol analysis provided insight about what the participants were thinking about the decisions made when attending to teacher questions and student thinking. All seven participants identified question types using language suggesting they understood the differences, but at a na(&)#239;ve level. Although participants used the correct language to show understanding of the question types, they had a fairly na(&)#239;ve understanding of the pedagogical purpose of the questions. This was especially true of the questions to elicit student ideas, but perhaps less true of the probing and challenging questions. The participants had more of a ritualistic understanding of the questions to elicit student ideas; they noticed them but perhaps did not have a deep understanding of this question type. Analyses of this study also revealed novice teachers learning is framed by the priorities of the public school system. All participants attended to teacher instruction, especially wait time and student engagement, while a few participants focused on feedback, praise, and higher- and lower-order questions. This study suggested school culture and the way teachers are now assessed may scaffold and support these teachers to have a more nuanced and sophisticated understanding of questioning and student thinking than has previously been reported for novice/beginning teachers. While some aspects of school culture and assessment may be problematic- i.e. wait time, feedback, praise, higher-order questions, etc.-on the whole it seems to be leading them in the right direction.
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Date Issued
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2014
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Identifier
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CFE0005153, ucf:50690
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0005153
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Title
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Virtual Router Approach for Wireless Ad Hoc Networks.
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Creator
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Ho, Ai, Hua, Kien, Guha, Ratan, Moshell, Jack, Zou, Changchun, Wang, Ching, University of Central Florida
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Abstract / Description
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Wireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an...
Show moreWireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an MANET is a self-organizing multi-hop wireless network in which all nodes within a given geographical area participate in the routing and data forwarding process. Such networks are scalable and self-healing. They support mobile applications where an infrastructure is either not available (e.g., rescue operations and underground networks) or not desirable (e.g., harsh industrial environments).In many ad hoc networks such as vehicular networks, links among nodes change constantly and rapidly due to high node speed. Maintaining communication links of an established communication path that extends between source and destination nodes is a significant challenge in mobile ad hoc networks due to movement of the mobile nodes. In particular, such communication links are often broken under a high mobility environment. Communication links can also be broken by obstacles such as buildings in a street environment that block radio signal. In a street environment, obstacles and fast moving nodes result in a very short window of communication between nodes on different streets. Although a new communication route can be established when a break in the communication path occurs, repeatedly reestablishing new routes incurs delay and substantial overhead. To address this limitation, we introduce the Virtual Router abstraction in this dissertation. A virtual router is a dynamically-created logical router that is associated with a particular geographical area. Its routing functionality is provided by the physical nodes (i.e., mobile devices) currently within the geographical region served by the virtual router. These physical nodes take turns in forwarding data packets for the virtual router. In this environment, data packets are transmitted from a source node to a destination node over a series of virtual routers. Since virtual routers do not move, this scheme is much less susceptible to node mobility. There can be two virtual router approaches: Static Virtual Router (SVR) and Dynamic Virtual Router (DVR). In SVR, the virtual routers are predetermined and shared by all communication sessions over time. This scheme requires each mobile node to have a map of the virtual routers, and use a global positioning system (GPS) to determine if the node is within the geographical region of a given router. DVR is different from SVR with the following distinctions: (1) virtual routers are dynamically created for each communication sessions as needed, and deprecated after their use; (2) mobile nodes do not need to have a GPS; and (3) mobile nodes do not need to know whereabouts of the virtual routers.In this dissertation, we apply Virtual Router approach to address mobility challenges in routing data. We first propose a data routing protocol that uses SVR to overcome the extreme fast topology change in a street environment. We then propose a routing protocol that does not require node locations by adapting a DVR approach. We also explore how the Virtual Router Approach can reduce the overhead associated with initial route or location requests used by many existing routing protocols to find a destination. An initial request for a destination is expensive because all the nodes need to be reached to locate the destination. We propose two broadcast protocols; one in an open terrain environment and the other in a street environment. Both broadcast protocols apply SVR. We provide simulation results to demonstrate the effectiveness of the proposed protocols in handling high mobility. They show Virtual Router approach can achieve several times better performance than traditional routing and broadcast approach based on physical routers (i.e., relay nodes).
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Date Issued
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2011
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Identifier
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CFE0004119, ucf:49090
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0004119
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Title
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A HYBRID ROUTING PROTOCOL FOR COMMUNICATIONS AMONG NODES WITHHIGH RELATIVE SPEED IN WIRELESS MESH NETWORKS.
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Creator
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PEPPAS, NIKOLAOS, Turgut, Damla, University of Central Florida
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Abstract / Description
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Wireless mesh networks (WMN) is a new promising wireless technology which uses already available hardware and software components. This thesis proposes a routing algorithm for military applications. More specifically, a specialized scenario consisting of a network of flying Unmanned Aerial Vehicles (UAVs) executing reconnaissance missions is investigated. The proposed routing algorithm is hybrid in nature and uses both reactive and proactive routing characteristics to transmit information....
Show moreWireless mesh networks (WMN) is a new promising wireless technology which uses already available hardware and software components. This thesis proposes a routing algorithm for military applications. More specifically, a specialized scenario consisting of a network of flying Unmanned Aerial Vehicles (UAVs) executing reconnaissance missions is investigated. The proposed routing algorithm is hybrid in nature and uses both reactive and proactive routing characteristics to transmit information. Through simulations run on a specially built stand alone simulator, based on Java, packet overhead, delivery ratio and latency metrics were monitored with respect to varying number of nodes, node density and mobility. The results showed that the high overhead leads to high delivery ratio while latency tends to increase as the network grows larger. All the metrics revealed sensitivity in high mobility conditions.
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Date Issued
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2007
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Identifier
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CFE0001607, ucf:47165
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0001607
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Title
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DEVELOPING STRAND SPACE BASED MODELS AND PROVING THE CORRECTNESS OF THE IEEE 802.11I AUTHENTICATION PROTOCOL WITH RESTRICTED SECURITY OBJECTIVES.
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Creator
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Furqan, Zeeshan, Guha, Ratan, University of Central Florida
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Abstract / Description
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The security objectives enforce the security policy, which defines what is to be protected in a network environment. The violation of these security objectives induces security threats. We introduce an explicit notion of security objectives for a security protocol. This notion should precede the formal verification process. In the absence of such a notion, the security protocol may be proven correct despite the fact that it is not equipped to defend against all potential threats. In order to...
Show moreThe security objectives enforce the security policy, which defines what is to be protected in a network environment. The violation of these security objectives induces security threats. We introduce an explicit notion of security objectives for a security protocol. This notion should precede the formal verification process. In the absence of such a notion, the security protocol may be proven correct despite the fact that it is not equipped to defend against all potential threats. In order to establish the correctness of security objectives, we present a formal model that provides basis for the formal verification of security protocols. We also develop the modal logic, proof based, and multi-agent approaches using the Strand Space framework. In our modal logic approach, we present the logical constructs to model a protocol's behavior in such a way that the participants can verify different security parameters by looking at their own run of the protocol. In our proof based model, we present a generic set of proofs to establish the correctness of a security protocol. We model the 802.11i protocol into our proof based system and then perform the formal verification of the authentication property. The intruder in our model is imbued with powerful capabilities and repercussions to possible attacks are evaluated. Our analysis proves that the authentication of 802.11i is not compromised in the presented model. We further demonstrate how changes in our model will yield a successful man-in-the-middle attack. Our multi-agent approach includes an explicit notion of multi-agent, which was missing in the Strand Space framework. The limitation of Strand Space framework is the assumption that all the information available to a principal is either supplied initially or is contained in messages received by that principal. However, other important information may also be available to a principal in a security setting, such as a principal may combine information from different roles played by him in a protocol to launch a powerful attack. Our presented approach models the behavior of a distributed system as a multi-agent system. The presented model captures the combined information, the formal model of knowledge, and the belief of agents over time. After building this formal model, we present a formal proof of authentication of the 4-way handshake of the 802.11i protocol.
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Date Issued
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2007
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Identifier
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CFE0001801, ucf:47380
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0001801
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Title
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LEADERS AND LAGGARDS: CLIMATE CHANGE MITIGATION POLICY IN THE EUROPEAN UNION AND THE UNITED STATES.
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Creator
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Breuer, Astrid, Bledsoe, Robert, University of Central Florida
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Abstract / Description
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In 1997, both the United States (U.S.) and the European Union (EU) signed the Kyoto Protocol, the first legally binding international treaty with targets for greenhouse gas emissions reductions. However, in 2001, the United States withdrew from the Protocol. This thesis seeks to understand some of the reasons why the European Union embraced the Kyoto Protocol while the United States did not. Using an overall framework of comparative politics, research is undertaken through three lenses. First...
Show moreIn 1997, both the United States (U.S.) and the European Union (EU) signed the Kyoto Protocol, the first legally binding international treaty with targets for greenhouse gas emissions reductions. However, in 2001, the United States withdrew from the Protocol. This thesis seeks to understand some of the reasons why the European Union embraced the Kyoto Protocol while the United States did not. Using an overall framework of comparative politics, research is undertaken through three lenses. First, an overview of public opinion toward global warming and climate change in the U.S. and the EU analyzes potential differences or similarities from surveys carried out in each area. Second, I examine the prevailing political ideology in each polity, with emphasis on the period when climate change arose as a major global challenge. Finally, two case studies examine the theory of environmental federalism and how it might affect climate change policy action. I obtained the following results. Public opinion research has revealed that, on average, the American public is nearly as concerned with climate change as the European public. However, the overarching political ideology in the U.S. was one of conservatism, while that in Europe was one of social democracy, with left and center-left governments, contributing to a greater or lesser degree, and through indirect mechanisms, to the political stances adopted. Finally, the case of Germany shows that member state actions, such as the implementation of ambitious reductions targets, can still play a crucial role in leadership even in the presence of action at the central government level (EU). The California case study shows that state-level efforts can rise to fill a vacuum created by the absence of central government action. In the end, behavior of each polity regarding international climate agreements, particularly the Kyoto Protocol, cannot be explained in simple terms. The complexity of the issues revolving climate change require further interdisciplinary research and collaboration among multiple actors including scientists, policymakers, nongovernmental organizations, and other stakeholders.
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Date Issued
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2011
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Identifier
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CFH0003840, ucf:44757
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFH0003840
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Title
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LEVELS OF LINE GRAPH QUESTION INTERPRETATION WITH INTERMEDIATE ELEMENTARY STUDENTS OF VARYING SCIENTIFIC AND MATHEMATICAL KNOWLEDGE AND ABILITY: A THINK ALOUD STUDY.
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Creator
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Keller, Stacy, Biraimah, Karen, University of Central Florida
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Abstract / Description
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This study examined how intermediate elementary students' mathematics and science background knowledge affected their interpretation of line graphs and how their interpretations were affected by graph question levels. A purposive sample of 14 6th-grade students engaged in think aloud interviews (Ericsson & Simon, 1993) while completing an excerpted Test of Graphing in Science (TOGS) (McKenzie & Padilla, 1986). Hand gestures were video recorded. Student performance on the TOGS was assessed...
Show moreThis study examined how intermediate elementary students' mathematics and science background knowledge affected their interpretation of line graphs and how their interpretations were affected by graph question levels. A purposive sample of 14 6th-grade students engaged in think aloud interviews (Ericsson & Simon, 1993) while completing an excerpted Test of Graphing in Science (TOGS) (McKenzie & Padilla, 1986). Hand gestures were video recorded. Student performance on the TOGS was assessed using an assessment rubric created from previously cited factors affecting students' graphing ability. Factors were categorized using Bertin's (1983) three graph question levels. The assessment rubric was validated by Padilla and a veteran mathematics and science teacher. Observational notes were also collected. Data were analyzed using Roth and Bowen's semiotic process of reading graphs (2001). Key findings from this analysis included differences in the use of heuristics, self-generated questions, science knowledge, and self-motivation. Students with higher prior achievement used a greater number and variety of heuristics and more often chose appropriate heuristics. They also monitored their understanding of the question and the adequacy of their strategy and answer by asking themselves questions. Most used their science knowledge spontaneously to check their understanding of the question and the adequacy of their answers. Students with lower and moderate prior achievement favored one heuristic even when it was not useful for answering the question and rarely asked their own questions. In some cases, if students with lower prior achievement had thought about their answers in the context of their science knowledge, they would have been able to recognize their errors. One student with lower prior achievement motivated herself when she thought the questions were too difficult. In addition, students answered the TOGS in one of three ways: as if they were mathematics word problems, science data to be analyzed, or they were confused and had to guess. A second set of findings corroborated how science background knowledge affected graph interpretation: correct science knowledge supported students' reasoning, but it was not necessary to answer any question correctly; correct science knowledge could not compensate for incomplete mathematics knowledge; and incorrect science knowledge often distracted students when they tried to use it while answering a question. Finally, using Roth and Bowen's (2001) two-stage semiotic model of reading graphs, representative vignettes showed emerging patterns from the study. This study added to our understanding of the role of science content knowledge during line graph interpretation, highlighted the importance of heuristics and mathematics procedural knowledge, and documented the importance of perception attentions, motivation, and students' self-generated questions. Recommendations were made for future research in line graph interpretation in mathematics and science education and for improving instruction in this area.
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Date Issued
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2008
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Identifier
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CFE0002356, ucf:47810
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002356
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Title
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Pervasive Secure Content Delivery Networks Implementation.
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Creator
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Lugo-Cordero, Hector, Guha, Ratan, Stanley, Kenneth, Chatterjee, Mainak, Wu, Annie, Lu, Kejie, University of Central Florida
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Abstract / Description
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Over the years, communication networks have been shifting their focus from providing connectivity in a client/server model to providing a service or content. This shift has led to topic areas like Service-Oriented Architecture (SOA), Heterogeneous Wireless Mesh Networks, and Ubiquitous Computing. Furthermore, probably the broadest of these areas which embarks all is the Internet of Things (IoT). The IoT is defined as an Internet where all physical entities (e.g., vehicles, appliances, smart...
Show moreOver the years, communication networks have been shifting their focus from providing connectivity in a client/server model to providing a service or content. This shift has led to topic areas like Service-Oriented Architecture (SOA), Heterogeneous Wireless Mesh Networks, and Ubiquitous Computing. Furthermore, probably the broadest of these areas which embarks all is the Internet of Things (IoT). The IoT is defined as an Internet where all physical entities (e.g., vehicles, appliances, smart phones, smart homes, computers, etc.), which we interact daily are connected and exchanging data among themselves and users. The IoT has become a global goal for companies, researchers, and users alike due to its different implementation and functional benefits: performance efficiency, coverage, economic and health. Due to the variety of devices which connect to it, it is expected that the IoT is composed of multiple technologies interacting together, to deliver a service. This technologies interactions renders an important challenge that must be overcome: how to communicate these technologies effectively and securely? The answer to this question is vital for a successful deployment of IoT and achievement of all the potential benefits that the IoT promises.This thesis proposes a SOA approach at the Network Layer to be able to integrate all technologies involved, in a transparent manner. The proposed set of solutions is composed of primarily the secure implementation of a unifying routing algorithm and a layered messaging model to standardizecommunication of all devices. Security is targeted to address the three main security concerns (i.e., confidentiality, integrity, and availability), with pervasive schemes that can be employed for any kind of device on the client, backbone, and server side. The implementation of such schemes is achieved by standard current security mechanisms (e.g., encryption), in combination with novel context and intelligent checks that detect compromised devices. Moreover, a decentralized content processing design is presented. In such design, content processing is handled at the client side, allowing server machines to serve more content, while being more reliable and capable of processing complete security checks on data and client integrity.
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Date Issued
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2017
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Identifier
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CFE0006620, ucf:51268
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0006620
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Title
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PREVENTING NEUROMUSCULAR DECONDITIONING IN CRITICALLY ILL PATIENTS.
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Creator
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Lakhani, Shahzia, Amidei, Christina, University of Central Florida
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Abstract / Description
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Critically ill patients can be prescribed bed rest as a therapeutic intervention. Immobility from bed rest can cause neuromuscular deconditioning and weakness. Preventing immobility by implementing mobilization activities may prevent these complications from occurring. Currently, mobility protocols are lacking. The purpose of this literature review is to analyze the evidence related to mobilizing patients in the Intensive Care Unit (ICU). In the future, a standard mobility protocol should be...
Show moreCritically ill patients can be prescribed bed rest as a therapeutic intervention. Immobility from bed rest can cause neuromuscular deconditioning and weakness. Preventing immobility by implementing mobilization activities may prevent these complications from occurring. Currently, mobility protocols are lacking. The purpose of this literature review is to analyze the evidence related to mobilizing patients in the Intensive Care Unit (ICU). In the future, a standard mobility protocol should be instituted for critically ill patients indicating when and how to begin mobilization. The efficacy of mobility protocols relies on an interdisciplinary team for positive outcomes to prevent complications of inactivity and promote patient safety. Future implementation of mobilization can decrease patients' lengths of stay and extensive rehabilitation from inactivity. Nursing education, practice and research should focus on interventions to prevent complications of immobility by identifying mobilization techniques, safety approaches and the use of protocols.
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Date Issued
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2011
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Identifier
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CFH0003847, ucf:44704
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFH0003847
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Title
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Effects of a Reading Strategy with Digital Social Studies Texts for Eighth Grade Students.
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Creator
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Doan, Melissa, Ehren, Barbara, Little, Mary, Kent-Walsh, Jennifer, Hahs-Vaughn, Debbie, University of Central Florida
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Abstract / Description
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Recent data indicate that only 34% of American eighth grade students are able to demonstrate grade-level proficiency with academic reading tasks (NCES, 2011). The staggering nature of statistics such as this is even more profound when considering that high level literacy skills combined with mastery of digital texts have become practical requirements for success in secondary education, post-secondary education, and virtually all vocational contexts. Despite this incongruent scenario, little...
Show moreRecent data indicate that only 34% of American eighth grade students are able to demonstrate grade-level proficiency with academic reading tasks (NCES, 2011). The staggering nature of statistics such as this is even more profound when considering that high level literacy skills combined with mastery of digital texts have become practical requirements for success in secondary education, post-secondary education, and virtually all vocational contexts. Despite this incongruent scenario, little research has been conducted to evaluate instructional methods and reading comprehension strategies with digital texts.To address this critical issue, the present study examined the effects of a metacognitive reading comprehension instructional protocol (STRUCTURE Your Reading [SYR]; Ehren, 2008) with eighth grade students using digital texts in a standard social studies classroom in an urban American school setting. The focus of the protocol was on teaching strategies and self-questioning prompts before, during, and after reading. The study employed a randomized controlled design and consisted of three conditions with a total of 4 participating teachers and 124 participating students. The study was conducted over 25 instructional days and two instructional units with 13.83 treatment hours within the standard, social studies classes. Hierarchical ANCOVA analyses revealed that when controlling for pre-test measurements, the comparison and experimental groups performed significantly better than the control group with instructional unit test scores (Unit 2), reading strategy use in all stages of reading (before, during, and after), and self-questioning prompts during reading. Comparison and experimental groups did not significantly differ in these gains, indicating that this instructional protocol is effective with both paper and digital text. These findings suggest that the SYR instructional protocol is effective with secondary students in content area classrooms when using digital text. Furthermore, they suggest that metacognition and reading comprehension strategy instruction are able to be successfully embedded within a content area class and result in academic and metacognitive gains. Clinical implications and future research directions and are discussed.
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Date Issued
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2012
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Identifier
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CFE0004244, ucf:49537
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0004244
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Title
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CONNECTIONLESS APPROACH A LOCALIZED SCHEME TO MOBILE AD HOC NETWORKS.
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Creator
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Ho, Yao, Hua, Kien, University of Central Florida
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Abstract / Description
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According to a Gartner Group (www.gartner.com) report in September 2008, the worldwide telecommunications market is on pace to reach $2 trillion in 2008. Gartner predicts that by 2012, the ratio of mobile to fixed connections will exceed 4-to-1. The North American mobile data market grew to 141.1 million connections in 2007, with a compound annual growth rate of 41.7 percent. It is believed that a large portion will be ad hoc and multi-hop connections, which will open many opportunities for...
Show moreAccording to a Gartner Group (www.gartner.com) report in September 2008, the worldwide telecommunications market is on pace to reach $2 trillion in 2008. Gartner predicts that by 2012, the ratio of mobile to fixed connections will exceed 4-to-1. The North American mobile data market grew to 141.1 million connections in 2007, with a compound annual growth rate of 41.7 percent. It is believed that a large portion will be ad hoc and multi-hop connections, which will open many opportunities for Mobile Ad hoc NETwork (MANET) applications and Wireless Mesh Network (WMN) applications. A MANET is a self-organizing multi-hop wireless network where all nodes participate in the routing and data forwarding process. Such a network can be easily deployed in situations where no base station is available, and a network must be build spontaneously. In applications such as battlefield communications, national crises, disaster recovery, and sensor deployment, a wired network is not available and ad hoc networks provide the only feasible means of communications and information access. Ad hoc networks have also become commonplace for gaming, conferencing, electronic classrooms, and particularly vehicle-to-vehicle communications. A Wireless mash network (WMN) is collection of mesh clients and mesh nodes (routers), with mesh nodes forming the backbone of the network and providing connection to the Internet and other network. Their rapid deployment and ease of maintenance are suitable for on-demand network such as disaster recovery, homeland security, convention centers, hard-to-wire buildings and unfriendly terrains. One important problem with MANET is the routing protocol that needs to work well not just with a small network, but also sustain efficiency and scalability as the network gets expanded and the application transmits data in greater volume. In such an environment, mobility, channel error, and congestion are the main causes for packet loss. Due to mobility of mobile hosts, addressing frequent and unpredictable topology changes is fundamental to MANET research. Two general approaches have been considered: connection-oriented approach and connectionless-oriented approach. In the former, the emphasis is on how to reconnect quickly with low overhead when a broken link occurs. Examples of this approach includes , , , , , , , , , and . In contrast, connectionless-oriented approach focuses on minimizing the occurrence of broken links. We proposed one such scheme called Connectionless Approach (CLA) and . In CLA, the network area is divided into non-overlapping grid cells, each serving as a virtual router. Any physical router (i.e., mobile host), currently inside a virtual router, can help forward the data packet to the next virtual router along the virtual link. This process is repeated until the packet reaches its final destination. Since a virtual link is based on virtual routers which do not move, it is much more robust than physical links used in the connection-oriented techniques. Simulation results in our previous works and , based on GloMoSim , indicate that CLA performs significantly better than connection-oriented techniques (i.e., AODV, DSR, LAR, GRID, TMNR, and GPSR). The contribution of this work consists of investigating and developing new Connectionless-Oriented Approach for Mobile Ad Hoc Network. Two of the greatest impacts of this research are as follows. First, the new approach is targeted towards robustly support high mobility and large scale environment which has been adapted for vehicle-to-vehicle environment in . Second, the detailed simulations which compare eight representative routing protocols, namely AODV, DSR, LAR, GRID, TMNR, GPSR, CBF, and CLA, under high-mobility environments. As many important emergent applications of the technology involved high-mobility nodes, very little is known about the existing routing methods perform relative to each other in high-mobility environments. The simulation results provide insight into ad hoc routing protocols and offer guidelines for mobile ad hoc network applications. Next, we enhanced and extend the connectionless-oriented approach. The current connectionless-oriented approach, however, may suffer from packet drops since traffic congestion is not considered in the packet forwarding policy. We address this weakness by considering the connectionless-oriented approach with a collision avoidance routing technique. After that, we investigate techniques to enforce collaboration among mobile devices in supporting the virtual router functionality. Many works have been published to combat such problem - misbehaving nodes are detected and a routing algorithm is employed to avoid and penalize misbehaving nodes. These techniques, however, cannot be applied to the connectionless-oriented approach since any node in the general direction towards the destination node can potentially help forward the data packets. To address the security and cooperation issues for connectionless-oriented approach, we introduce a cooperation enforcement technique called 3CE (3-Counter Enforcement). In addition, wireless mesh networks have become increasingly popular in recent years. Wireless mash network (WMNs) are collection of mesh clients and mesh nodes (routers), with mesh nodes forming the backbone of the network and providing connection to the Internet and other network. We propose a paradigm that combines virtual routers and mesh nodes to create a hybrid network call VR-Mesh Network. This hybrid network can reduce number of mesh node needed without decrease the performance of the network.
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Date Issued
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2009
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Identifier
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CFE0002742, ucf:48146
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0002742
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Title
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A NEW FRAMEWORK FOR QOS PROVISIONING IN WIRELESS LANS USING THE P-PERSISTENT MAC PROTOCOL.
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Creator
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Anna, Kiran Babu, Bassiouni, Mostafa, University of Central Florida
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Abstract / Description
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The support of multimedia traffic over IEEE 802.11 wireless local area networks (WLANs) has recently received considerable attention. This dissertation has proposed a new framework that provides efficient channel access, service differentiation and statistical QoS guarantees in the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e. In the first part of the dissertation, the new framework to provide QoS support in IEEE 802.11e is presented. The framework uses three...
Show moreThe support of multimedia traffic over IEEE 802.11 wireless local area networks (WLANs) has recently received considerable attention. This dissertation has proposed a new framework that provides efficient channel access, service differentiation and statistical QoS guarantees in the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e. In the first part of the dissertation, the new framework to provide QoS support in IEEE 802.11e is presented. The framework uses three independent components, namely, a core MAC layer, a scheduler, and an admission control. The core MAC layer concentrates on the channel access mechanism to improve the overall system efficiency. The scheduler provides service differentiation according to the weights assigned to each Access Category (AC). The admission control provides statistical QoS guarantees. The core MAC layer developed in this dissertation employs a P-Persistent based MAC protocol. A weight-based fair scheduler to obtain throughput service differentiation at each node has been used. In wireless LANs (WLANs), the MAC protocol is the main element that determines the efficiency of sharing the limited communication bandwidth of the wireless channel. In the second part of the dissertation, analytical Markov chain models for the P-Persistent 802.11 MAC protocol under unsaturated load conditions with heterogeneous loads are developed. The Markov models provide closed-form formulas for calculating the packet service time, the packet end-to-end delay, and the channel capacity in the unsaturated load conditions. The accuracy of the models has been validated by extensive NS2 simulation tests and the models are shown to give accurate results. In the final part of the dissertation, the admission control mechanism is developed and evaluated. The analytical model for P-Persistent 802.11 is used to develop a measurement-assisted model-based admission control. The proposed admission control mechanism uses delay as an admission criterion. Both distributed and centralized admission control schemes are developed and the performance results show that both schemes perform very efficiently in providing the QoS guarantees. Since the distributed admission scheme control does not have a complete state information of the WLAN, its performance is generally inferior to the centralized admission control scheme. The detailed performance results using the NS2 simulator have demonstrated the effectiveness of the proposed framework. Compared to 802.11e EDCA, the scheduler consistently achieved the desired throughput differentiation and easy tuning. The core MAC layer achieved better delays in terms of channel access, average packet service time and end-to-end delay. It also achieved higher system throughput than EDCA for any given service differentiation ratio. The admission control provided the desired statistical QoS guarantees.
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Date Issued
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2010
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Identifier
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CFE0003243, ucf:48513
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0003243
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Title
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Closing the Gaps in Professional Development: A Tool for School-based Leadership Teams.
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Creator
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Sampayo, Sandra, Boote, David, Hayes, Grant, Vitale, Thomas, Flanigan, Jacquelyn, University of Central Florida
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Abstract / Description
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The field of professional learning in education has been studied and added to extensively in the last few decades. Because the importance of learning in authentic contexts through professional dialogue has become so important, high quality, school-based professional learning is vital to building capacity at the school level. Unfortunately, the literature on professional development (PD) does not provide much guidance on how to bridge theory and practice at the school level, creating a gap....
Show moreThe field of professional learning in education has been studied and added to extensively in the last few decades. Because the importance of learning in authentic contexts through professional dialogue has become so important, high quality, school-based professional learning is vital to building capacity at the school level. Unfortunately, the literature on professional development (PD) does not provide much guidance on how to bridge theory and practice at the school level, creating a gap. With the goal of PD ultimately being to improve teacher performance and student learning, the problem with this gap is that school-level professional development is arbitrarily planned, resulting in variable outcomes. I propose the reason for this is schools lack a comprehensive framework or tool that guides the design of a quality professional learning plan. This problem was identified in Orange County Public School and this dissertation in practice aims at developing a solution that accounts for the district's specific contextual needs. My proposed solution is the design of an integrative tool that school leaders can use to guide them through the professional development planning process. The School-based Professional Learning Design Tool incorporates the professional development standards in planning, learning, implementing, and evaluating outlined in the Florida Professional Development System Evaluation Protocol. It also guides leaders in taking an inventory of the culture and context of their school in order to plan PD that will be viable given those considerations. The components of the Tool guide teams through assessing school teacher performance and student achievement data to help identify focus groups; determining gaps in learning through root cause analysis; creating goals aligned to gaps in performance; and selecting strategies for professional learning, follow-up support, and evaluation. The development of the Tool was informed by the extant literature on professional development, organizational theory, state and national standards for professional development, and principles of design. The Tool is to be completed in four phases. Phases one and two, the focus of this paper, include the literature review, organizational assessment, design specifications, and the first iteration of the Tool. In the next phases, the goals are to solicit feedback from an expert panel review, create a complete version of the Tool, and pilot it in elementary schools. Although the development of the Tool through its final phases will refine it considerably, there are limitations that will transcend all iterations. While the Tool incorporates best practices in professional development, the lack of empirical evidence on the effectiveness of specific PD elements in the literature renders this Tool only a best guess in helping schools plan effective professional development. Another limitation is that the Tool is not prescriptive and cannot use school data to make decisions for what strategies to implement. Taking these limitations into consideration, the use of this Tool can significantly impact the quality and effectiveness of professional development in schools.
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Date Issued
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2015
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Identifier
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CFE0005883, ucf:50889
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0005883
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Title
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A framework for interoperability on the United States electric grid infrastructure.
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Creator
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Laval, Stuart, Rabelo, Luis, Zheng, Qipeng, Xanthopoulos, Petros, Ajayi, Richard, University of Central Florida
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Abstract / Description
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Historically, the United States (US) electric grid has been a stable one-way power delivery infrastructure that supplies centrally-generated electricity to its predictably consuming demand. However, the US electric grid is now undergoing a huge transformation from a simple and static system to a complex and dynamic network, which is starting to interconnect intermittent distributed energy resources (DERs), portable electric vehicles (EVs), and load-altering home automation devices, that...
Show moreHistorically, the United States (US) electric grid has been a stable one-way power delivery infrastructure that supplies centrally-generated electricity to its predictably consuming demand. However, the US electric grid is now undergoing a huge transformation from a simple and static system to a complex and dynamic network, which is starting to interconnect intermittent distributed energy resources (DERs), portable electric vehicles (EVs), and load-altering home automation devices, that create bidirectional power flow or stochastic load behavior. In order for this grid of the future to effectively embrace the high penetration of these disruptive and fast-responding digital technologies without compromising its safety, reliability, and affordability, plug-and-play interoperability within the field area network must be enabled between operational technology (OT), information technology (IT), and telecommunication assets in order to seamlessly and securely integrate into the electric utility's operations and planning systems in a modular, flexible, and scalable fashion. This research proposes a potential approach to simplifying the translation and contextualization of operational data on the electric grid without being routed to the utility datacenter for a control decision. This methodology integrates modern software technology from other industries, along with utility industry-standard semantic models, to overcome information siloes and enable interoperability. By leveraging industrial engineering tools, a framework is also developed to help devise a reference architecture and use-case application process that is applied and validated at a US electric utility.
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Date Issued
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2015
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Identifier
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CFE0005647, ucf:50193
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0005647
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Title
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DIGITIZATION PROTOCOLS AND APPLICATIONS FOR LASER SCANNING HUMAN BONE IN FORENSIC ANTHROPOLOGY.
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Creator
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Filiault, Matthew, Schultz, John, University of Central Florida
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Abstract / Description
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In medico-legal investigations involving unidentified skeletal remains, forensic anthropologists commonly assist law enforcement and medical examiners in their analysis and identification. The traditional documentation techniques employed by the forensic anthropologist during their analysis include notes, photographs, measurements and radiographic images. However, relevant visual information of the skeleton can be lacking in morphological details in 2D images. By creating a 3D representation...
Show moreIn medico-legal investigations involving unidentified skeletal remains, forensic anthropologists commonly assist law enforcement and medical examiners in their analysis and identification. The traditional documentation techniques employed by the forensic anthropologist during their analysis include notes, photographs, measurements and radiographic images. However, relevant visual information of the skeleton can be lacking in morphological details in 2D images. By creating a 3D representation of individual bones using a laser-scanner, it would be possible to overcome this limitation. Now that laser scanners have become increasingly affordable, this technology should be incorporated in the documentation methodologies of forensic anthropology laboratories. Unfortunately, this equipment is rarely used in forensic anthropology casework. The goal of this project is to investigate the possible visualization applications that can be created from digitized surface models of bone for use in medico-legal investigations. This research will be achieved in two phases. First, examples of human bone as well as replicas of bone will be scanned using a NextEngineâ„¢ laser scanner. In conjunction with this will be the exploration and documentation of protocols for scanning different bone types and processing the scan data for creating a 3D model. The second phase will investigate how the resulting 3D model can be used in lieu of the actual remains to achieve improved documentation methodologies through the use of several commercial computer graphics programs. The results demonstrate that an array of visual applications can be easily created from a 3D file of bone, including virtual curation, measurement, illustration and the virtual reconstruction of fragmented bone. Based on the findings of this project, the implementation of laser scanning technology is recommended for forensic anthropology labs to enhance documentation, analysis and presentation of human bone.
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Date Issued
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2012
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Identifier
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CFH0004287, ucf:44907
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFH0004287