Routing in Delay Tolerant Networks Using Storage Domains

Affiliation: Padma Mundur is with the Institute for Advanced Computer Studies (UMIACS), University of Maryland, College Park, MD 20742 (e-mail: [email protected]). Sookyoung Lee is with the Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, MD 21250 (e-mail: [email protected]). Matthew Seligman is with the Laboratory for Telecommunication Sciences (LTS), 8080 Greenmead Road College Park, MD 20742 (e-mail: [email protected]).In this paper, we present a routing algorithm for a class of dynamic networks called the Delay Tolerant Networks (DTNs). The proposed algorithm takes into account the quintessential DTN characteristic namely, intermittent link connectivity. We modify the breadth first search (BFS) algorithm to take into account link state changes and find the quickest route between source and destination nodes. We adopt a message drop policy at intermediate nodes to incorporate storage constraint. We also introduce the idea of time-varying storage domains where all nodes connected for a length of time act as a single storage unit by sharing the aggregated storage capacity of the nodes. We evaluate the routing algorithm with and without storage domain in an extensive simulation. We analyze the performance using metrics such as delivery ratio, incomplete transfers with no routes and dropped messages. The DTN topology dynamics are analyzed by varying: number of nodes generating traffic, link probability, link availability through combinations of downtime/uptime values, storage per node, message size, and traffic. The delay performance of the proposed algorithms is conceptually the same as flooding-based algorithms but without the penalty of multiple copies. More significantly, we show that the Quickest Storage Domain (Quickest SD) algorithm distributes the storage demand across many nodes in the network topology, enabling balanced load and higher network utilization. In fact, we show that for the same level of performance, we can actually cut the storage requirement in half using the Quickest SD algorithm

Cyr61 Expression is associated with prognosis in patients with colorectal cancer

BACKGROUND: Cysteine-rich 61 (Cyr61), a member of the CCN protein family, possesses diverse functionality in cellular processes such as adhesion, migration, proliferation, and survival. Cyr61 can also function as an oncogene or a tumour suppressor, depending on the origin of the cancer. Only a few studies have reported Cyr61 expression in colorectal cancer. In this study, we assessed the Cyr61 expression in 251 colorectal cancers with clinical follow up. METHODS: We examined Cyr61 expression in 6 colorectal cancer cell lines (HT29, Colo205, Lovo, HCT116, SW480, SW620) and 20 sets of paired normal and colorectal cancer tissues by western blot. To validate the association of Cyr61 expression with clinicopathological parameters, we assessed Cyr61 expression using tissue microarray analysis of primary colorectal cancer by immunohistochemical analysis. RESULTS: We verified that all of the cancer cell lines expressed Cyr61; 2 cell lines (HT29 and Colo205) demonstrated Cyr61 expression to a slight extent, while 4 cell lines (Lovo, HCT116, SW480, SW620) demonstrated greater Cyr61 expression than HT29 and Colo205 cell lines. Among the 20 cases of paired normal and tumour tissues, greater Cyr61 expression was observed in 16 (80%) tumour tissues than in normal tissues. Furthermore, 157 out of 251 cases (62.5%) of colorectal cancer examined in this study displayed strong Cyr61 expression. Cyr61 expression was found to be associated with pN (p = 0.018). Moreover, Cyr61 expression was associated with statistically significant cancer-specific mortality (p = 0.029). The duration of survival was significantly lesser in patients with Cyr61 high expression than in patients with Cyr61 low expression (p = 0.001). These results suggest that Cyr61 expression plays several important roles in carcinogenesis and may also be a good prognostic marker for colorectal cancer. CONCLUSIONS: Our data confirmed that Cyr61 was expressed in colorectal cancers and the expression was correlated with worse prognosis of colorectal cancers

Overview of the Characteristics of Micro- and Nano-Structured Surface Plasmon Resonance Sensors

The performance of bio-chemical sensing devices has been greatly improved by the development of surface plasmon resonance (SPR) based sensors. Advancements in micro- and nano-fabrication technologies have led to a variety of structures in SPR sensing systems being proposed. In this review, SPR sensors (from typical Kretschmann prism configurations to fiber sensor schemes) with micro- or nano-structures for local light field enhancement, extraordinary optical transmission, interference of surface plasmon waves, plasmonic cavities, etc. are discussed. We summarize and compare their performances and present guidelines for the design of SPR sensors

Real‐world clinical effectiveness and safety of CT‐P10 in patients with diffuse large B‐cell lymphoma: An observational study in Europe

The rituximab biosimilar CT‐P10 is approved for the treatment of non‐Hodgkin lymphoma. Previous studies have demonstrated clinical similarity between CT‐P10 and reference rituximab. However, real‐world data relating to treatment in patients with DLBCL with rituximab biosimilars are limited. This study collected real‐world data relating to the effectiveness and safety of CT‐P10 treatment from the medical records of 389 patients with DLBCL (24 centers, five European countries). For the primary outcome (clinical effectiveness), overall survival (OS), progression‐free survival (PFS), and best response (BR) were assessed. The percentage (95% confidence interval [95% CI]) of patients alive at 12‐, 18‐, and 30 months postindex (initiation of CT‐P10) was 86% (82.4%–89.4%), 81% (76.9%–84.9%), and 76% (71.2%–80.1%), respectively. The PFS rate (percent, [95% CI]) at 12‐, 18‐, and 30 months postindex was 78% (74.2%–82.5%), 72% (67.9%–76.9%), and 67% (61.9%–71.7%), respectively. Median OS/PFS was not reached. For 82% (n = 312) of patients, the BR to CT‐P10 was a complete response. Adverse events were consistent with known effects of chemotherapy. This international, multicenter study provides real‐world data on the safety and effectiveness profile of CT‐P10 for DLBCL treatment and supports the adoption of CT‐P10 for the treatment of DLBCL

Relatório de estágio em farmácia comunitária

Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr

The Prosaics of Weak Modernism

This dissertation puts philosophies of existence in dialogue with general and historical grammar to describe the moments in which a style comes into being. Cultivating a poetics of prose hinged between nineteenth-century realism and an emergent aesthetics yet to be called modernism, the dissertation identifies in the Bildungsroman of D. H. Lawrence and James Joyce the “weak” -- non-narrative and non-explicative -- means of circumscribing structures of reflection into linguistic forms. The formal undercurrent found in proto-modernist novels, in which grammatical functions exploit the modes of the “subject” or “agency” operating in the narrative, persists throughout the long twentieth century. I turn to Doris Lessing and a generation of mid-century critics whose writings are hinged between the modernist avant-garde and a formal exhaustion yet to be called postmodernism. The existential grammar of modern narratives presented in the dissertation show that the dynamics of historic accumulation inverts the dynamics of language to the point of its utmost evacuation

Optimized Relay Node Placement for Federating Wireless Sensor Sub-Networks

Wireless sensor networks (WSNs) have recently received increasing attention due to a growing list of applications. Most notable among the applications are those in harsh environments, such as coast and border protection, search-and-rescue and battlefield reconnaissance. A WSN in these applications may get partitioned into multiple disjoint segments (sub-networks) due to major damage in some part of the network, e.g. inflicted by explosions in battlefield. Since WSNs are often employed to assist in risky missions and to deal with the event that caused the damage itself, it is desired to connect these disjoint partitions in order to restore the full operation of the network. In addition, linking sub-networks may be mandatory in some application setups in which there are multiple autonomous, independently-operating, WSNs that need to collaborate to perform a joint task. For example, a number of existing stand-alone WSNs may be required to operate jointly in order to deal with a major disaster. Connecting multiple WSNs or segments of a damaged WSN is referred to as federation in this dissertation. In this dissertation, we tackle the challenges in federating a partitioned WSN or autonomous wireless sensor sub-networks. In particular, we form a federated system of multiple network segments by deploying the least number of additional relay nodes in the proper locations. We focus on two major factors related to relay placement. The first is the connectivity requirement which is characterized by the distances between every pair of two segments. Those distances may be longer than twice the communication range of a single relay node, which requires consideration of the inter-relay connectivity. In addition, linking the segments may be subject to varying inter-segment quality of service (QoS) requirements. Since finding the optimal count and position of relay nodes is known to be NP-hard, we pursue heuristics. We present three novel approaches in this dissertation. The first approach populates relays towards the center of the area to form a connected inter-segment topology. In the second approach, we design a distributed self-healing algorithm which repositions existing mobile nodes to connect the segments. The third approach incrementally places the relays, addressing the connectivity and QoS requirements one path at a time. It opts to minimize the number of required relays to establish connectivity by maximizing the resource utilization of the deployed nodes. The correctness, convergence and time complexity of those proposed approaches are analyzed and their effectiveness is evaluated through extensive simulation experiments. The resulting topology is also analyzed in comparison to alternate solutions found in the literature

A Multi-Hop Clustering Mechanism for Scalable IoT Networks

It is expected that up to 26 billion Internet of Things (IoT) equipped with sensors and wireless communication capabilities will be connected to the Internet by 2020 for various purposes. With a large scale IoT network, having each node connected to the Internet with an individual connection may face serious scalability issues. The scalability problem of the IoT network may be alleviated by grouping the nodes of the IoT network into clusters and having a representative node in each cluster connect to the Internet on behalf of the other nodes in the cluster instead of having a per-node Internet connection and communication. In this paper, we propose a multi-hop clustering mechanism for IoT networks to minimize the number of required Internet connections. Specifically, the objective of proposed mechanism is to select the minimum number of coordinators, which take the role of a representative node for the cluster, i.e., having the Internet connection on behalf of the rest of the nodes in the cluster and to map a partition of the IoT nodes onto the selected set of coordinators to minimize the total distance between the nodes and their respective coordinator under a certain constraint in terms of maximum hop count between the IoT nodes and their respective coordinator. Since this problem can be mapped into a set cover problem which is known as NP-hard, we pursue a heuristic approach to solve the problem and analyze the complexity of the proposed solution. Through a set of experiments with varying parameters, the proposed scheme shows 63–87.3% reduction of the Internet connections depending on the number of the IoT nodes while that of the optimal solution is 65.6–89.9% in a small scale network. Moreover, it is shown that the performance characteristics of the proposed mechanism coincide with expected performance characteristics of the optimal solution in a large-scale network