ROUTING IN MOBILE AD-HOC NETWORKS: SCALABILITY AND EFFICIENCY

Mobile Ad-hoc Networks (MANETs) have received considerable research interest in recent years. Because of dynamic topology and limited resources, it is challenging to design routing protocols for MANETs. In this dissertation, we focus on the scalability and efficiency problems in designing routing protocols for MANETs. We design the Way Point Routing (WPR) model for medium to large networks. WPR selects a number of nodes on a route as waypoints and divides the route into segments at the waypoints. Waypoint nodes run a high-level inter-segment routing protocol, and nodes on each segment run a low-level intra-segment routing protocol. We use DSR and AODV as the inter-segment and the intra-segment routing protocols, respectively. We term this instantiation the DSR Over AODV (DOA) routing protocol. We develop Salvaging Route Reply (SRR) to salvage undeliverable route reply (RREP) messages. We propose two SRR schemes: SRR1 and SRR2. In SRR1, a salvor actively broadcasts a one-hop salvage request to find an alternative path to the source. In SRR2, nodes passively learn an alternative path from duplicate route request (RREQ) packets. A salvor uses the alternative path to forward a RREP when the original path is broken. We propose Multiple-Target Route Discovery (MTRD) to aggregate multiple route requests into one RREQ message and to discover multiple targets simultaneously. When a source initiates a route discovery, it first tries to attach its request to existing RREQ packets that it relays. MTRD improves routing performance by reducing the number of regular route discoveries. We develop a new scheme called Bilateral Route Discovery (BRD), in which both source and destination actively participate in a route discovery process. BRD consists of two halves: a source route discovery and a destination route discovery, each searching for the other. BRD has the potential to reduce control overhead by one half. We propose an efficient and generalized approach called Accumulated Path Metric (APM) to support High-Throughput Metrics (HTMs). APM finds the shortest path without collecting topology information and without running a shortest-path algorithm. Moreover, we develop the Broadcast Ordering (BO) technique to suppress unnecessary RREQ transmissions

Libraries and Total Quality: Making the Patron a Partner

Libraries began to see service competition for the first time in the 1990s, due to the Internet and Google. The necessity of being more customer-focused became apparent, and this resulted in the creation of LibQUAL+, a tool developed to quantitatively measure the quality of customer service (Saunders, 2007). While LibQUAL+ serves as a first step toward increasing quality and value for patrons, library commitment to responding to survey results is essential. Although LibQUAL+ has been used by a wide range of libraries, this paper focuses on the use of LibQUAL+ by academic libraries, using two university libraries (Vanderbilt University and the University of Pittsburgh) as sample cases for assessing library response to survey results. The theme of engaging the patron as a partner is further explored by examining a procurement project at the University of California at Los Angeles

Libraries and Total Quality: Making the Patron a Partner

Libraries began to see service competition for the first time in the 1990s, due to the Internet and Google. The necessity of being more customer-focused became apparent, and this resulted in the creation of LibQUAL+, a tool developed to quantitatively measure the quality of customer service (Saunders, 2007). While LibQUAL+ serves as a first step toward increasing quality and value for patrons, library commitment to responding to survey results is essential. Although LibQUAL+ has been used by a wide range of libraries, this paper focuses on the use of LibQUAL+ by academic libraries, using two university libraries (Vanderbilt University and the University of Pittsburgh) as sample cases for assessing library response to survey results. The theme of engaging the patron as a partner is further explored by examining a procurement project at the University of California at Los Angeles

Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs

Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake – it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and timeconsuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RREP. Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SRR, and the simulation results confirm the effectiveness of the SRR approach

EgoNet: Identification of human disease ego-network modules

Background: Mining novel biomarkers from gene expression profiles for accurate disease classification is challenging due to small sample size and high noise in gene expression measurements. Several studies have proposed integrated analyses of microarray data and protein-protein interaction (PPI) networks to find diagnostic subnetwork markers. However, the neighborhood relationship among network member genes has not been fully considered by those methods, leaving many potential gene markers unidentified. The main idea of this study is to take full advantage of the biological observation that genes associated with the same or similar diseases commonly reside in the same neighborhood of molecular networks.Results: We present EgoNet, a novel method based on egocentric network-analysis techniques, to exhaustively search and prioritize disease subnetworks and gene markers from a large-scale biological network. When applied to a triple-negative breast cancer (TNBC) microarray dataset, the top selected modules contain both known gene markers in TNBC and novel candidates, such as RAD51 and DOK1, which play a central role in their respective ego-networks by connecting many differentially expressed genes.Conclusions: Our results suggest that EgoNet, which is based on the ego network concept, allows the identification of novel biomarkers and provides a deeper understanding of their roles in complex diseases

GJB2 mutation spectrum in 2063 Chinese patients with nonsyndromic hearing impairment

Background: Mutations in GJB2 are the most common molecular defects responsible for autosomal recessive nonsyndromic hearing impairment (NSHI). The mutation spectra of this gene vary among different ethnic groups. Methods: In order to understand the spectrum and frequency of GJB2 mutations in the Chinese population, the coding region of the GJB2 gene from 2063 unrelated patients with NSHI was PCR amplified and sequenced. Results: A total of 23 pathogenic mutations were identified. Among them, five (p.W3X, c.99delT, c.155_c.158delTCTG, c.512_c.513insAACG, and p.Y152X) are novel. Three hundred and seven patients carry two confirmed pathogenic mutations, including 178 homozygotes and 129 compound heterozygotes. One hundred twenty five patients carry only one mutant allele. Thus, GJB2 mutations account for 17.9% of the mutant alleles in 2063 NSHI patients. Overall, 92.6% (684/739) of the pathogenic mutations are frame-shift truncation or nonsense mutations. The four prevalent mutations; c.235delC, c.299_c.300delAT, c.176_c.191del16, and c.35delG, account for 88.0% of all mutantalleles identified. The frequency of GJB2 mutations (alleles) varies from 4% to 30.4% among different regions of China. It also varies among different sub-ethnic groups. Conclusion: In some regions of China, testing of the three most common mutations can identify at least one GJB2 mutant allele in all patients. In other regions such as Tibet, the three most common mutations account for only 16% the GJB2 mutant alleles. Thus, in this region, sequencing of GJB2 would be recommended. In addition, the etiology of more than 80% of the mutant alleles for NSHI in China remains to be identified. Analysis of other NSHI related genes will be necessary

Salvaging Route Reply for On-Demand Routing Protocols in Mobile Ad-Hoc Networks

On-demand routing protocols are preferred in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination sends a route reply (RREP) message to the source after receiving the RREQ. The RREP travels hop by hop on the discovered route in reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to the dynamic network topology or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet- discard the packet and send a route error message to the destination (initiator of the RREP). This is highly unacceptable because a RREP message has a lot at stake- it is obtained by a large number of RREQ transmissions, which is an expensive and time-consuming process. Furthermore, the source may have to start another round of route discovery to establish the route because of the loss of the RREP. This will exacerbate the situation. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. SRR attempts to salvage an undeliverable RREP in two possible ways: looking up the route cache for an alternate path and conducting a one-hop SRR route discovery. We present an implementation of SRR in AODV routing protocol. The results of an extensive simulation study confirm the performance improvement in all critical metrics, namely, packet delivery ratio, control overhead and end-to-end delay

Getting a Good Read

Libraries began to see service competition for the first time in the 1990s, due to the Internet and Google. The necessity of being more customer-focused became apparent, and this resulted in the creation of LibQUAL+, a tool developed to quantitatively measure the quality of customer service (Saunders, 2007). While LibQUAL+ serves as a first step toward increasing quality and value for patrons, library commitment to responding to survey results is essential.Although LibQUAL+ has been used by a wide range of libraries, this paper focuses on the use of LibQUAL+ by academic libraries, using two university libraries (Vanderbilt University and the University of Pittsburgh) as sample cases for assessing library response to survey results. The theme of engaging the patron as a partner is further explored by examining a procurement project at the University of California at Los Angeles.Todd Bruns ORCID: http://orcid.org/0000-0002-1197-252

Natural narratives: the Spinozan conception of truth in the Tractatus de Intellectus Emendatione

O objetivo deste trabalho é o exame da concepção espinosista da verdade, com ênfase no Tractatus de intellectus emendatione (TIE). Para tanto, empreendemos a análise da teoria das idéias, presente nesse texto, em um cotejo com as demais obras do autor. Apesar disso, privilegiamos o TIE dentre as demais, com o propósito de mostrar que essa obra não é uma fase superada. Com efeito, tem-se considerado o TIE como um fracasso de Espinosa pelo fato de o filósofo não ter conseguido nele elaborar a definição do intelecto. Entretanto, o que pretendemos mostrar é que, mesmo se nao inteiramente explicitada, a definição do intelecto pode ser ali encontrada e que, portanto, a tradicional interpretacao dos editores e comentadores - apesar de longamente endossada - está equivocada. De fato, tornou-se uma convenção dizer que o TIE não possui uma densa articulação com o sistema espinosista. Mostraremos, ao contrario, que ela não apenas existe, mas pode ser perfeitamente comprovada.The objective of this work is to investigate the Spinozan concept of truth, with emphasis on the Tractatus de intellectus emendatione (TIE). In order to do so, we have analysed his theory of ideas, presented in this text, in close comparison with that presented in the rest of Spinoza\'s work. Despite this, we have given pride of place to the TIE over the rest, with the firm purpose of showing that this work is not merely a passing phase. In effect, the TIE has been considered, over the years, a Spinoza failure for its (apparent) lack of elaboration of the definition of the intellect. However, what we intend to do is to show that, even if not in an explicit way, the definition of the intellect is there and, therefore, that the editors\' and commentators\' traditional interpretation - despite its being amply endorsed - is wrong. In fact, it has become conventional to say that the TIE does not articulate easily with the core of Spinoza\'s system. It is our purpose, nonetheless, to show that not only does this articulation exist, but also that it can be thoroughly and consistently supported