Journal articles on the topic 'Failed nodes'
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Kim, Kwangsoo, Jae-Yeon Jin, and Seong-il Jin. "Classification between Failed Nodes and Left Nodes in Mobile Asset Tracking Systems †." Sensors 16, no. 2 (February 18, 2016): 240. http://dx.doi.org/10.3390/s16020240.
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Li, Shudong, Yanshan Chen, Xiaobo Wu, Xiaochun Cheng, and Zhihong Tian. "Power Grid-Oriented Cascading Failure Vulnerability Identifying Method Based on Wireless Sensors." Journal of Sensors 2021 (June 26, 2021): 1–12. http://dx.doi.org/10.1155/2021/8820413.
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In our paper, we study the vulnerability in cascading failures of the real-world network (power grid) under intentional attacks. Here, we use three indexes ( B , K , k -shell) to measure the importance of nodes; that is, we define three attacks, respectively. Under these attacks, we measure the process of cascade effect in network by the number of avalanche nodes, the time steps, and the speed of the cascade propagation. Also, we define the node’s bearing capacity as a tolerant parameter to study the robustness of the network under three attacks. Taking the power grid as an example, we have obtained a good regularity of the collapse of the network when the node’s affordability is low. In terms of time and speed, under the betweenness-based attacks, the network collapses faster, but for the number of avalanche nodes, under the degree-based attack, the number of the failed nodes is highest. When the nodes’ bearing capacity becomes large, the regularity of the network’s performances is not obvious. The findings can be applied to identify the vulnerable nodes in real networks such as wireless sensor networks and improve their robustness against different attacks.
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Panda, Sanjaya Kumar, and Saswati Naik. "An Efficient Data Replication Algorithm for Distributed Systems." International Journal of Cloud Applications and Computing 8, no. 3 (July 2018): 60–77. http://dx.doi.org/10.4018/ijcac.2018070105.
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This article describes how data replication plays an important role in distributed systems. It primarily focuses on the redundancy of data at two or more nodes, to achieve both fault tolerance and improved performance. Therefore, many researchers have proposed various data replication algorithms to manage the redundancy of data. However, they have not considered the faults that are associated with the nodes, such as permanent, transient and intermittent. Moreover, they have not incorporated any recovery approach to rejoin the failed nodes. Therefore, the authors propose a data replication algorithm, called dynamic vote-based data replication (DVDR). The main contribution of DVDR is to consider all types of faults and rejoin the failed nodes. DVDR is based on dynamic vote assignment among the connected nodes, and referred as passive and non-hierarchical one. The authors perform rigorous analysis of DVDR and compare with an existing dynamic vote assignment algorithm. The result shows the efficacy of the proposed algorithm.
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Yu, Seog Kun, and Eon Kyeong Joo. "LDPC Decoding by Failed Check Nodes for Serial Concatenated Code." ETRI Journal 37, no. 1 (February 1, 2015): 54–60. http://dx.doi.org/10.4218/etrij.15.0114.0107.
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Zou, Yi, and Krishnendu Chakrabarty. "Redundancy Analysis and a Distributed Self-Organization Protocol for Fault-Tolerant Wireless Sensor Networks." International Journal of Distributed Sensor Networks 3, no. 3 (July 2007): 243–72. http://dx.doi.org/10.1080/15501320600781078.
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Sensor nodes in a distributed sensor network can fail due to a variety of reasons, e.g., harsh environmental conditions, sabotage, battery failure, and component wear-out. Since many wireless sensor networks are intended to operate in an unattended manner after deployment, failing nodes cannot be replaced or repaired during field operation. Therefore, by designing the network to be fault-tolerant, we can ensure that a wireless sensor network can perform its surveillance and tracking tasks even when some nodes in the network fail. In this paper, we describe a fault-tolerant self-organization scheme that designates a set of backup nodes to replace failed nodes and maintain a backbone for coverage and communication. The proposed scheme does not require a centralized server for monitoring node failures and for designating backup nodes to replace failed nodes. It operates in a fully distributed manner and it requires only localized communication. This scheme has been implemented on top of an energy-efficient self-organization technique for sensor networks. The proposed fault-tolerance-node selection procedure can tolerate a large number of node failures using only localized communication, without losing either sensing coverage or communication connectivity.
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WU, J. J., H. J. SUN, and Z. Y. GAO. "CAPACITY ASSIGNMENT MODEL TO DEFENSE CASCADING FAILURES." International Journal of Modern Physics C 20, no. 07 (July 2009): 991–99. http://dx.doi.org/10.1142/s0129183109014126.
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How to alleviate the damages of cascading failures triggered by the overload of edges/nodes is common in complex networks. To describe the whole cascading failures process from edges overloading to nodes malfunctioning and the dynamic spanning clustering with the evolvement of traffic flow, we propose a capacity assignment model by introducing an equilibrium assignment rule of flow in artificially created scale-free traffic networks. Additionally, the capacity update rule of node is given in this paper. We show that a single failed edge may undergo the cascading failures of nodes, and a small failure has the potential to trigger a global cascade. It is suggested that enhancing the capacity of node is particularly important for the design of any complex network to defense the cascading failures. Meanwhile, it has very important theoretical significance and practical application worthiness in the development of effective methods to alleviate the damage of one or some failed edges/nodes.
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Jaenigen, Bernd, Gian Kayser, Berthold Steinke, and Oliver Thomusch. "Five-Year Long-Term Followup of a Primary Lymph node Gastrinoma: Is a Pancreaticoduodenectomy Justified?" Case Reports in Medicine 2009 (2009): 1–4. http://dx.doi.org/10.1155/2009/762791.
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Background. Gastrinoma-positive lymph nodes and failed localization of the primary tumor during surgical exploration are described. Specialists suppose that these lymph nodes are metastases rather than a primary gastrinoma.Methods. Case report with a five-year long-term followup. A 60-year-old patient with an confirmed gastrinoma was treated in our department. All preoperative evaluations including somatostatin-receptor-scintigraphy and F-Dopa PET failed to localize the gastrinoma. Explorative laparotomy revealed a gastrinoma in two peripancreatic lymph nodes. Despite extensive intraoperative exploration, no primary gastrinoma could be detected in typical localization.Results. Over a period of 5 years, the patient's gastrin level stayed in the normal range and the patient seems to be completely cured.Conclusion. A prophylactic partial pancreatoduodenectomy is not indicated to avoid recurrence, since complete biochemical cure by local resection of the lymph node gastrinoma is possible.
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Nautiyal, Nisha, S. B. Singh, and Soni Bisht. "Analysis of reliability and its characteristics of a k-out-of-n network incorporating copula." International Journal of Quality & Reliability Management 37, no. 4 (March 2, 2020): 517–37. http://dx.doi.org/10.1108/ijqrm-08-2018-0224.
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PurposeThe present paper focuses on the evaluation of reliability and its characteristics (Mean time to failure and Sensitivity) of a k-out-of-n network.Design/methodology/approachThe minimal cuts of the network have been evaluated for different nodes in this paper, using an algorithm. With the help of these cuts, reliability and its characteristics are obtained using Gumbel–Hougaard family of the copula.FindingsThe present paper proposes to compute the reliability and its measures of the k-out-of-n network using the minimal cuts and copula methodology. The completely failed nodes of the network have been repaired using Gumbel–Hougaard family of the copula.Originality/valueIn this paper, the reliability of a k-out-of-n network has been evaluated by first calculating k-out-of-n minimal cuts, and the failed nodes have also been repaired using Gumbel–Hougaard family of the copula, unlike as done in the past.
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Chae, Yee Soo, Soo Jung Lee, In Hee Lee, Jin Hyang Jung, Ho Yong Park, Jeeyeon Lee, Won Hwa Kim, and Hye Jung Kim. "Ultrasound-guided dual-localization for axillary nodes before and after neoadjuvant chemotherapy with clip and activated charcoal in breast cancer patients: A feasibility study." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e12067-e12067. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e12067.
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e12067 Background: We report on our experience of ultrasound (US)-guided dual-localization for axillary nodes before and after neoadjuvant chemotherapy (NAC) with clip and activated charcoal to guide axillary surgery in breast cancer patients. Methods: Between November 2017 and May 2018, a dual-localization procedure was performed under US guidance for the most suspicious axillary nodes noted at initial staging (before NAC, with clip) and restaging (after NAC, with activated charcoal) in 28 cytologically proven node-positive breast cancer patients. Patients underwent axillary sampling or dissection, which involved removing not only the sentinel nodes (SNs), but also clipped nodes (CNs) and tattooed nodes (TNs). Success (or failure) rates of biopsies of SNs, CNs, and TNs and inter-nodal concordance rates were determined. Sensitivities for the individual and combined biopsies were calculated. Results: SN biopsy failed in four patients (14%), whereas the CN biopsy failed in one patient (4%). All TNs were identified in the surgical field. Concordance rates were 79% for CNs–TNs, 63% for CNs–SNs, and 58% for TNs–SNs. Sensitivity for SN, CN, and TN biopsy was 73%, 67%, and 67%, respectively. Sensitivity was 80% for any combination of biopsies (SN plus CN, SN plus TN, SN plus CN plus TN). Conclusions: US-guided dual-localization of axillary nodes before and after NAC with clip and activated charcoal was a feasible approach that might facilitate more reliable nodal staging with less-invasive strategies in node-positive breast cancer patients.
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Khan, Muhammad Amir, Halabi Hasbullah, Babar Nazir, and Imran Ali Khan. "An Energy Efficient Simultaneous-Node Repositioning Algorithm for Mobile Sensor Networks." Scientific World Journal 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/785305.
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Recently, wireless sensor network (WSN) applications have seen an increase in interest. In search and rescue, battlefield reconnaissance, and some other such applications, so that a survey of the area of interest can be made collectively, a set of mobile nodes is deployed. Keeping the network nodes connected is vital for WSNs to be effective. The provision of connectivity can be made at the time of startup and can be maintained by carefully coordinating the nodes when they move. However, if a node suddenly fails, the network could be partitioned to cause communication problems. Recently, several methods that use the relocation of nodes for connectivity restoration have been proposed. However, these methods have the tendency to not consider the potential coverage loss in some locations. This paper addresses the concerns of both connectivity and coverage in an integrated way so that this gap can be filled. A novel algorithm for simultaneous-node repositioning is introduced. In this approach, each neighbour of the failed node, one by one, moves in for a certain amount of time to take the place of the failed node, after which it returns to its original location in the network. The effectiveness of this algorithm has been verified by the simulation results.
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Chen, Wei, and Peng Liu. "Reliability Evaluation for Binary Directed Tree-Structured Systems Based on Terminal Failure Limit-Value." Applied Mechanics and Materials 63-64 (June 2011): 268–72. http://dx.doi.org/10.4028/www.scientific.net/amm.63-64.268.
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This paper evaluates reliability of binary directed tree-structured systems based on terminal failure limit-value. For the difficult problem with complex structures and directed transitive relation, the paper describes nodes in the tree system using set algebra, and uses set operations to compute a combinational mode of failed nodes, and then describes it with family of sets. On that basis, an effective algorithm is shown, and a numerical example is given to illustrate the algorithm obtained in the paper.
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Khalid, Mustafa, and Dheyaa Jasim. "MDFD and DFD Methods to detect Failed Sensor Nodes in Wireless Sensor Network." International Journal of Computer Applications 124, no. 13 (August 18, 2015): 14–18. http://dx.doi.org/10.5120/ijca2015905732.
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Yang, Qi, Xuan Zhang, Jingfeng Qian, and Qiang Ye. "An anomaly node detection method for distributed time synchronization algorithm in cognitive radio sensor networks." International Journal of Distributed Sensor Networks 14, no. 5 (May 2018): 155014771877446. http://dx.doi.org/10.1177/1550147718774467.
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In wireless sensor networks, time synchronization is an important issue for all nodes to have a unified time. The wireless sensor network nodes should cooperatively adjust their local time according to certain distributed synchronization algorithms to achieve global time synchronization. Conventionally, it is assumed that all nodes in the network are cooperative and well-functioned in the synchronization process. However, in cognitive radio wireless sensor networks, the global time synchronization process among secondary users is prone to fail because the communication process for exchanging synchronization reference may be frequently interrupted by the primary users. The anomaly nodes that failed to synchronize will significantly affect the global convergence performance of the synchronization algorithm. This article proposes an anomaly node detection method for distributed time synchronization algorithm in cognitive radio sensor networks. The proposed method adopts the statistical linear correlation analysis approach to detect anomaly nodes through the historical time synchronization information stored in local nodes. Simulation results show that the proposed method can effectively improve the robustness of the synchronization algorithm in distributed cognitive radio sensor networks.
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Gong, Kai, Jia-Jian Wu, Ying Liu, Qing Li, Run-Ran Liu, and Ming Tang. "The Effective Healing Strategy against Localized Attacks on Interdependent Spatially Embedded Networks." Complexity 2019 (May 15, 2019): 1–10. http://dx.doi.org/10.1155/2019/7912857.
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Many real-world infrastructure networks, such as power grids and communication networks, always depend on each other by their functional components that share geographic proximity. A lot of works were devoted to revealing the vulnerability of interdependent spatially embedded networks (ISENs) when facing node failures and showed that the ISENs are susceptible to geographically localized attacks caused by natural disasters or terrorist attacks. How to take emergency methods to prevent large scale of cascading failures on interdependent infrastructures is a longstanding problem. Here, we propose an effective strategy for the healing of local structures using the connection profile of a failed node, called the healing strategy by prioritizing minimum degrees (HPMD), in which a new link between two active low-degree neighbors of a failed node is established during the cascading process. Afterwards, comparisons are made between HPMD and three healing strategies based on three metrics: random choice, degree centrality, and local centrality, respectively. Simulations are performed on the ISENs composed of two diluted square lattices with the same size under localized attacks. Results show that HPMD can significantly improve the robustness of the system by enhancing the connectivity of low-degree nodes, which prevent the diffusion of failures from low-degree nodes to moderate-degree nodes. In particular, HPMD can outperform other three strategies in the size of the giant component of networks, critical attack radius, and the number of iterative cascade steps for a given quota of newly added links, which means HPMD is more effective, more timely, and less costly. The high performance of HPMD indicates low-degree nodes should be placed on the top priority for effective healing to resist the cascading of failures in the ISENs, which is totally different from the traditional methods that usually take high-degree nodes as critical nodes in a single network. Furthermore, HPMD considers the distance between a pair of nodes to control the variation in the network structures, which is more applicable to spatial networks than previous methods.
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Jeon, Young, Taehong Kim, and Taejoon Kim. "Fast and Robust Time Synchronization with Median Kalman Filtering for Mobile Ad-Hoc Networks." Sensors 21, no. 2 (January 15, 2021): 590. http://dx.doi.org/10.3390/s21020590.
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Time synchronization is an important issue in ad-hoc networks for reliable information exchange. The algorithms for time synchronization in ad-hoc networks are largely categorized into two types. One is based on a selection of a reference node, and the other is based on a consensus among neighbor nodes. These two types of methods are targeting static environments. However, synchronization errors among nodes increase sharply when nodes move or when incorrect synchronization information is exchanged due to the failure of some nodes. In this paper, we propose a synchronization technique for mobile ad-hoc networks, which considers both the mobility of nodes and the abnormal behaviors of malicious or failed nodes. Specifically, synchronization information extracted from a median of the time information of the neighbor nodes is quickly disseminated. This information effectively excludes the outliers, which adversely affect the synchronization of the networks. In addition, Kalman filtering is applied to reduce the synchronization error occurring in the transmission and reception of time information. The simulation results confirm that the proposed scheme has a fast synchronization convergence speed and low synchronization error compared to conventional algorithms.
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Hori, Atsushi, Kazumi Yoshinaga, Thomas Herault, Aurélien Bouteiller, George Bosilca, and Yutaka Ishikawa. "Overhead of using spare nodes." International Journal of High Performance Computing Applications 34, no. 2 (February 4, 2020): 208–26. http://dx.doi.org/10.1177/1094342020901885.
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With the increasing fault rate on high-end supercomputers, the topic of fault tolerance has been gathering attention. To cope with this situation, various fault-tolerance techniques are under investigation; these include user-level, algorithm-based fault-tolerance techniques and parallel execution environments that enable jobs to continue following node failure. Even with these techniques, some programs with static load balancing, such as stencil computation, may underperform after a failure recovery. Even when spare nodes are present, they are not always substituted for failed nodes in an effective way. This article considers the questions of how spare nodes should be allocated, how to substitute them for faulty nodes, and how much the communication performance is affected by such a substitution. The third question stems from the modification of the rank mapping by node substitutions, which can incur additional message collisions. In a stencil computation, rank mapping is done in a straightforward way on a Cartesian network without incurring any message collisions. However, once a substitution has occurred, the optimal node-rank mapping may be destroyed. Therefore, these questions must be answered in a way that minimizes the degradation of communication performance. In this article, several spare node allocation and failed node substitution methods will be proposed, analyzed, and compared in terms of communication performance following the substitution. The proposed substitution methods are named sliding methods. The sliding methods are analyzed by using our developed simulation program and evaluated by using the K computer, Blue Gene/Q (BG/Q), and TSUBAME 2.5. It will be shown that when failures occur, the stencil communication performance on the K and BG/Q can be slowed around 10 times depending on the number of node failures. The barrier performance on the K can be cut in half. On BG/Q, barrier performance can be slowed by a factor of 10. Further, it will also be shown that almost no such communication performance degradation can be seen on TSUBAME 2.5. This is because TSUBAME 2.5 has an Infiniband network connected with a FatTree topology, while the K computer and BG/Q have dedicated Cartesian networks. Thus, the communication performance degradation depends on network characteristics.
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Wiener, R. Constance, and Alcinda K. Trickett Shockey. "Smoking and Heberden Nodes: Analysis of Data from the Osteoarthritis Initiative." Advances in Epidemiology 2016 (April 26, 2016): 1–7. http://dx.doi.org/10.1155/2016/2083683.
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Purpose. Dental hygienists, dentists, and other workforce providers who depend upon their hands for employment are acutely aware of the need to protect their hands to ensure a successful career. Recent research has suggested that smoking may be protective of hand osteoarthritis. The purpose of this study is to determine the association between smoking and Heberden’s nodes. Methods. Data from the Osteoarthritis Initiative were used in a cross-sectional, secondary data analysis of self-reported current smoking/never smoking and the presence/absence of Heberden’s nodes, the hard enlargements of the joints nearest the fingertips (distal interphalangeal joints). Analyses included descriptive statistics, Chi-square associations with Heberden’s nodes, and logistic regressions. Results. In adjusted analysis, smoking had an adjusted odds ratio for Heberden’s nodes of 0.832 [95% confidence interval: 0.60, 1.14] which failed to reach significance (P=.2488). In the selected model, females were more likely than males to have Heberden’s nodes; non-Hispanic Blacks were less likely than non-Hispanic Whites to have Heberden’s nodes; and older age groups were more likely than the youngest age group to have Heberden’s nodes. Conclusion. Smoking did not provide protection against Heberden’s nodes in this study of US participants in the Osteoarthritis Initiative.
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Awan, Adnan Anwar, Muhammad Amir Khan, Aqdas Naveed Malik, Syed Ayaz Ali Shah, Aamir Shahzad, Babar Nazir, Iftikhar Ahmed Khan, Waqas Jadoon, Naveed Shahzad, and Rab Nawaz Jadoon. "Quality of Service-Based Node Relocation Technique for Mobile Sensor Networks." Wireless Communications and Mobile Computing 2019 (August 22, 2019): 1–13. http://dx.doi.org/10.1155/2019/5043187.
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Wireless sensor networks (WSNs) deployed in harsh and unfavorable environments become inoperable because of the failure of multiple sensor nodes. This results into the division of WSNs into small disjoint networks and causes stoppage of the transmission to the sink node. Furthermore, the internodal collaboration among sensor nodes also gets disturbed. Internodal connectivity is essential for the usefulness of WSNs. The arrangement of this connectivity could be setup at the time of network startup. If multiple sensor nodes fail, the tasks assigned to those nodes cannot be performed; hence, the objective of such WSNs will be compromised. Recently, different techniques for repositioning of sensor nodes to recover the connectivity have been proposed. Although capable to restore connectivity, these techniques do not focus on the coverage loss. The objective of this research is to provide a solution for both coverage and connectivity via an integrated approach. A novel technique to reposition neighbouring nodes for multinode failure is introduced. In this technique, neighbouring nodes of the failed nodes relocate themselves one by one and come back to their original location after some allocated time. Hence, it restores both prefailure connectivity and coverage. The simulations show our proposed technique outperforms other baseline techniques.
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Mahmood, Khalid, Muhammad Amir Khan, Mahmood ul Hassan, Ansar Munir Shah, Shahzad Ali, and Muhammad Kashif Saeed. "Intelligent On-Demand Connectivity Restoration for Wireless Sensor Networks." Wireless Communications and Mobile Computing 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/9702650.
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Wireless sensor networks are envisioned to play a very important role in the Internet of Things in near future and therefore the challenges associated with wireless sensor networks have attracted researchers from all around the globe. A common issue which is well studied is how to restore network connectivity in case of failure of single or multiple nodes. Energy being a scarce resource in sensor networks drives all the proposed solutions to connectivity restoration to be energy efficient. In this paper we introduce an intelligent on-demand connectivity restoration technique for wireless sensor networks to address the connectivity restoration problem, where nodes utilize their transmission range to ensure the connectivity and the replacement of failed nodes with their redundant nodes. The proposed technique helps us to keep track of system topology and can respond to node failures effectively. Thus our system can better handle the issue of node failure by introducing less overhead on sensor node, more efficient energy utilization, better coverage, and connectivity without moving the sensor nodes.
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Vimala M. and Rajeev Ranjan. "Energy Efficient Clustering using Modified Multi-Hop Clustering." International Journal of Wireless Networks and Broadband Technologies 8, no. 2 (July 2019): 18–30. http://dx.doi.org/10.4018/ijwnbt.2019070103.
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In recent years, WSN has been widely used for building the decision support system (DSS) for solving the real-world problem. Moreover, out of several fields, one of the interesting fields that requires DSS is the monitoring of agriculture environment. Nowadays, monitoring an agricultural environment has become one of the essential fields. IoT has been one of the eminent technologies in recent years and WSN model has played the parallel role into it. These sensors have a limited power supply and this affects the efficiency of the algorithm. In the past, several methods have been proposed for efficient clustering, however, these methods fail to provide satisfactory accuracy. Hence, this article proposes an energy efficient methodology named modified multi-hop clustering (MMHC). This methodology takes three steps. The first step is assembling the nodes where the nodes are assembled, the second step couples the nodes, and the third step detects the redundant nodes and discard them. The main advantage of MMHC is that it can select multiple redundant nodes at one time and discard, and this makes the algorithm more fast and efficient. Moreover, in order to evaluate the algorithm several parameters have been considered, such as energy consumption, number of failed nodes, number of active nodes, and communication overhead.
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Sangwan, Anju, and Rishipal Singh. "Secure Deployment with Optimal Connectivity in Wireless Sensor Networks." International Journal of Mobile Computing and Multimedia Communications 7, no. 2 (April 2016): 1–21. http://dx.doi.org/10.4018/ijmcmc.2016040101.
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In the hostile areas, deployment of the sensor nodes in wireless sensor networks is one of the basic issue to be addressed. The node deployment method has great impact on the performance metrics like connectivity, security and resilience. In this paper, a technique based on strong keying mechanism is proposed which will enhance the security of a non-homogeneous network using the random deployment of the nodes. For this, the q-composite key pre-distribution technique is presented with new flavor that will enhance the network size as well as the security level in comparison to the existing techniques. The technique ensures the k-connectivity among the nodes with a redundant method to provide backup for failed nodes. In the simulation section, the performance of the proposed scheme is evaluated using NS-2 based upon the real model MICAz. A discussion based on various obtained results is also given in the paper.
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Hedar, Abdel-Rahman, Shada N. Abdulaziz, Emad Mabrouk, and Gamal A. El-Sayed. "Wireless Sensor Networks Fault-Tolerance Based on Graph Domination with Parallel Scatter Search." Sensors 20, no. 12 (June 21, 2020): 3509. http://dx.doi.org/10.3390/s20123509.
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In wireless sensor/ad hoc networks, all wireless nodes frequently flood the network channel by transmitting control messages causing “broadcast storm problem”. Thus, inspired by the physical backbone in wired networks, a Virtual Backbone (VB) in wireless sensor/ad hoc networks can help achieve efficient broadcasting. A well-known and well-researched approach for constructing virtual backbone is solving the Connected Dominating Set (CDS) problem. Furthermore, minimizing the size of the CDS is a significant research issue. We propose a new parallel scatter search algorithm with elite and featured cores for constructing a wireless sensor/ad hoc network virtual backbones based on finding minimum connected dominating sets of wireless nodes. Also, we addressed the problem of VB node/nodes failure by either deploying a previously computed VBs provided by the main pSSEF algorithm that does not contain the failed node/nodes, or by using our proposed FT-pSSEF algorithm repairing the broken VBs. Finally, as nodes in a VB incur extra load of communication and computation, this leads to faster power consumption compared to other nodes in the network. Consequently, we propose the virtual backbone scheduling algorithm SC-pSSEF which aims to find multiple VBs using the VBs provided by the pSSEF algorithm and switch between them periodically to prolong the network life time.
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Wang, Huan, Chunming Qiao, Xuan Guo, Lei Fang, Ying Sha, and Zhiguo Gong. "Identifying and Evaluating Anomalous Structural Change-based Nodes in Generalized Dynamic Social Networks." ACM Transactions on the Web 15, no. 4 (June 11, 2021): 1–22. http://dx.doi.org/10.1145/3457906.
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Recently, dynamic social network research has attracted a great amount of attention, especially in the area of anomaly analysis that analyzes the anomalous change in the evolution of dynamic social networks. However, most of the current research focused on anomaly analysis of the macro representation of dynamic social networks and failed to analyze the nodes that have anomalous structural changes at a micro level. To identify and evaluate anomalous structural change-based nodes in generalized dynamic social networks that only have limited structural information, this research considers undirected and unweighted graphs and develops a multiple-neighbor superposition similarity method ( ), which mainly consists of a multiple-neighbor range algorithm ( ) and a superposition similarity fluctuation algorithm ( ). introduces observation nodes, characterizes the structural similarities of nodes within multiple-neighbor ranges, and proposes a new multiple-neighbor similarity index on the basis of extensional similarity indices. Subsequently, maximally reflects the structural change of each node, using a new superposition similarity fluctuation index from the perspective of diverse multiple-neighbor similarities. As a result, based on and , not only identifies anomalous structural change-based nodes by detecting the anomalous structural changes of nodes but also evaluates their anomalous degrees by quantifying these changes. Results obtained by comparing with state-of-the-art methods via extensive experiments show that can accurately identify anomalous structural change-based nodes and evaluate their anomalous degrees well.
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Jahromi, Alireza Hamidian, Sankaran Narayanan, Fiona MacNeill, Peter Osin, Ashutash Nerurkar, and Gerald Gui. "Testing the Feasibility of Intra-Operative Sentinel Lymph Node Touch Imprint Cytology." Annals of The Royal College of Surgeons of England 91, no. 4 (May 2009): 336–39. http://dx.doi.org/10.1308/rcsann.2009.91.4.336.
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INTRODUCTION Sentinel lymph node biopsy is emerging as the new standard for axillary staging in breast cancer. Intra-operative assessment of the sentinel lymph nodes allows immediate completion of axillary dissection during the same anaesthetic. This project was a quality assurance practice to establish feasibility, time-to-report, as well as accuracy of performing intra-operative assessment of sentinel lymph nodes using touch imprint cytology in our centre. PATIENTS AND METHODS This prospective audit included 146 sentinel lymph nodes from 74 consecutive patients with invasive breast cancer. All patients underwent axillary sentinel lymph node biopsy using combined blue dye and radiocolloid technique. Results of intra-operative touch imprint cytology using haematoxylin and eosin staining were compared with the definitive histopathology results. RESULTS Mean time to report touch imprint cytology was 25.7 ± 6.4 min (range, 15–40 min). Histopathology demonstrated metastasis in 25 sentinel nodes from 17 (23%) patients. Intra-operative touch imprint cytology detected 15 nodes in 11 patients, giving a sensitivity of 60% (nodes) and 66.7% (patients) and specificity of 99.2% (nodes) and 98.2% (patients) based on the number of nodes and patients involved, respectively. Touch imprint cytology failed to show metastatic involvement in 10 nodes from 6 patients; of these, five nodes had micrometastasis (< 2 mm) and the other five had macrometastasis. One touch imprint cytology positive node contained isolated tumour cells only. Using intra-operative touch imprint cytology made a change in treatment of 11(14.9%) patients, and spared second axillary procedure in 7 (9.4%) patients. CONCLUSIONS Intra-operative sentinel lymph node assessment using touch imprint cytology is feasible within a busy NHS practice. We now offer touch imprint cytology to patients following appropriate counselling.
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Zhang, Wei, Shu-Ying Bai, and Rui Jin. "The model of microblog message diffusion based on complex social network." International Journal of Modern Physics B 28, no. 20 (June 19, 2014): 1450136. http://dx.doi.org/10.1142/s0217979214501367.
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Microblog is a micromessage communication network in which users are the nodes and the followship between users are the edges. Sina Weibo is a typical case of these microblog service websites. As the enormous scale of nodes and complex links in the network, we choose a sample network crawled in Sina Weibo as the base of empirical analysis. The study starts with the analysis of its topological features, and brings in epidemiological SEIR model to explore the mode of message spreading throughout the microblog network. It is found that the network is obvious small-world and scale-free, which made it succeed in transferring messages and failed in resisting negative influence. In addition, the paper focuses on the rich nodes as they constitute a typical feature of Sina Weibo. It is also found that whether the message starts with a rich node will not account for its final coverage. Actually, the rich nodes always play the role of pivotal intermediaries who speed up the spreading and make the message known by much more people.
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Liu, Kai Fei, and Xiao Liu. "Emergency Policy for Perishable Products Supply Chain when Nodes Fail." Advanced Materials Research 317-319 (August 2011): 2097–102. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.2097.
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Emergency management is becoming more and more important with the vulnerability increasing in global supply chain. An effective policy which is emergency strategy stock based for perishable supply chain emergency scheduling with a failed produce node has been proposed. Mixed integer programming model was build under the inventory policy of perishable products which include both of raw materials and finished products. The simulation results show that our policy of the model is effective, and could solve these problems completely.
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Lin, Yi-Kuel. "Unreliability evaluation for a limited-flow network with failed nodes subject to the budget constraint." Computers & Mathematics with Applications 51, no. 1 (January 2006): 73–82. http://dx.doi.org/10.1016/j.camwa.2005.06.012.
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UPADHYAYA, SHAMBHU J., and I.-SHYAN HWANG. "DESIGN OF A MULTI-LEVEL FAULT-TOLERANT MESH (MFTM) FOR HIGH RELIABILITY APPLICATIONS." International Journal of Reliability, Quality and Safety Engineering 02, no. 04 (December 1995): 419–29. http://dx.doi.org/10.1142/s0218539395000290.
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This paper presents a novel technique for the enhancement of operational reliability of processor arrays by a multi-level fault-tolerant design approach. The key idea of the design is based on the well known hierarchical design paradigm. The proposed fault-tolerant architecture uses a flexible reconfiguration of redundant nodes, thereby offering a better spare utilization than existing two-level redundancy schemes. A variable number of spares is provided at each level of redundancy which enables a flexible reconfiguration as well as area efficient layouts and better spare utilization. The spare nodes at each level can replace any of the failed primary nodes, not only at the same level but also those at the lower levels. The architecture can be adopted to increase the system reliability in Multi Chip Modules (MCMs). The main contributions of our work are the higher degree of fault tolerance, higher overall reliability, flexibility, and a better spare utilization.
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Lakshmi Siva Rama Krishna, T., J. Priyanka, N. Nikhil Teja, Sd Mahiya Sultana, and B. Jabber. "An Efficient Data Replication Scheme for Hadoop Distributed File System." International Journal of Engineering & Technology 7, no. 2.32 (May 31, 2018): 167. http://dx.doi.org/10.14419/ijet.v7i2.32.15396.
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A Distributed file system (DFS) is a storage component of a distributed system (DS). DS consists of multiple autonomous nodes connected via a communication network to solve large problems and to achieve more computing power. One of the design requirement of any DS is to provide replicas. In this paper, we propose a new replication algorithm which is more reliable than the existing replication algorithm used in DFS. The advantages of our proposed replication algorithm by incrementing nodes sequentially (RAINS) is that it distributes the storage load equally among all the nodes sequentially and it guarantees a replica copy in case two racks in a DS are down. This feature is not available in the existing DFS. We have compared existing replication algorithm used by Hadoop distributed file system (HDFS) with our proposed RAINS algorithm. The experimental results indicate that our proposed RAINS algorithm performs better when more number of racks failed in the DS.
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Cozzolino, F., M. Torcia, A. M. Carossino, R. Giordani, C. Selli, G. Talini, E. Reali, A. Novelli, V. Pistoia, and M. Ferrarini. "Characterization of cells from invaded lymph nodes in patients with solid tumors. Lymphokine requirement for tumor-specific lymphoproliferative response." Journal of Experimental Medicine 166, no. 2 (August 1, 1987): 303–18. http://dx.doi.org/10.1084/jem.166.2.303.
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The specific immune response against the malignant cells was investigated in patients with urinary bladder or larynx cancer. Lymphocytes from lymph nodes that drain the tumor site were tested for their proliferative and cytotoxic capacities against autologous malignant cells isolated from the primary tumor. In no occasion was a proliferative or a cytotoxic response observed. However, when the lymph node cell suspensions were depleted of cells expressing both OKM1 and Leu-7 markers by rosetting with the appropriate mAbs, a proliferative response could be observed. The lymphocytes responded to autologous tumor cells only if IL-2 was added to the cultures. IL-2 alone induced some cell proliferation, which was not, however, comparable to that observed in response to both IL-2 and tumor cells. A panel of allogeneic tumor cells consistently failed to stimulate OKM1-, Leu-7- cells in vitro. Response to autologous tumor cells was not caused by HLA-encoded molecules, as occurs in the autologous mixed lymphocyte reaction, since OKM1-, Leu-7- cells failed to be stimulated by autologous non-T cells. A proliferative response was observed only with cells from lymph nodes that had been classified as invaded by malignant cells according to histopathologic criteria. Cells from noninvaded lymph nodes consistently failed to respond. Cells stimulated with autologous tumor cells could be expanded in short-term lines by continuous addition of IL-2 and malignant cells. One of these lines, which comprised mainly T8+ cells, was stimulated to proliferate only by autologous tumor cells, and its proliferative response was inhibitable by anti-class I and not by anti-class II mAbs. This line showed lytic capacities against autologous malignant targets, while it was inefficient against all of the other allogeneic cells tested. In another set of experiments, the mechanisms whereby exogenous IL-2 had to be added to the cultures to sustain a proliferative response against neoplastic cells were investigated. When cocultured with autologous malignant cells, OKM1-, Leu-7- lymphocytes expressed IL-2 receptors, as could be assessed by anti-Tac fluorescent staining. Under these culture conditions, these cells did not produce IL-2, and no proliferation was observed. Addition of purified IL-1 to the cultures induced IL-2 production and cell proliferation. It is concluded that metastatic lymph nodes contain a T cell population that can be detected in a proliferative assay when both suppressor cells are removed and the appropriate molecular signals are supplied.
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Subbian, Selvakumar, Liana Tsenova, Guibin Yang, Paul O'Brien, Sven Parsons, Blas Peixoto, Leslie Taylor, Dorothy Fallows, and Gilla Kaplan. "Chronic pulmonary cavitary tuberculosis in rabbits: a failed host immune response." Open Biology 1, no. 4 (December 2011): 110016. http://dx.doi.org/10.1098/rsob.110016.
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The molecular determinants of the immune response to Mycobacterium tuberculosis HN878 infection in a rabbit model of pulmonary cavitary tuberculosis were studied. Aerosol infection of rabbits resulted in a highly differentially expressed global transcriptome in the lungs at 2 weeks, which dropped at 4 weeks and then gradually increased. While IFNγ was progressively upregulated throughout the infection, several other genes in the IFNγ network were not. T-cell activation network genes were gradually upregulated and maximally induced at 12 weeks. Similarly, the IL4 and B-cell activation networks were progressively upregulated, many reaching high levels between 12 and 16 weeks. Delayed peak expression of genes associated with macrophage activation and Th1 type immunity was noted. Although spleen CD4 + and CD8 + T cells showed maximal tuberculosis antigen-specific activation by 8 weeks, macrophage activation in lungs, lymph nodes and spleen did not peak until 12 weeks. In the lungs, infecting bacilli grew exponentially up to 4 weeks, followed by a steady-state high bacillary load to 12 weeks that moderately increased during cavitation at 16 weeks. Thus, the outcome of HN878 infection of rabbits was determined early during infection by a suboptimal activation of innate immunity and delayed T-cell activation.
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Goyal, A., A. Douglas-Jones, R. G. Newcombe, and R. E. Mansel. "Objective assessment of sentinel node tumor burden and its impact on sentinel node localisation in breast cancer." Journal of Clinical Oncology 24, no. 18_suppl (June 20, 2006): 605. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.605.
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605 Background: Extensive tumor infiltration of the draining lymph nodes may prevent the migration of tracer to the sentinel node(SN), adversely affecting SN identification. Methods: A total of 202 breast cancer patients underwent SN biopsy using 99mTc albumin colloid and Patent Blue V injected peritumorally. This was followed by standard axillary clearance in all patients at the same operation. Tumor burden in the SN was assessed by measuring the size of metastasis, percentage replacement(PR) of the SN by tumor and by documenting extranodal invasion(EI). Digital images of the marked slides were acquired and measurements were made using Image Pro Plus software. Results: The overall SN identification rate was 94.6% (191/202), of which 5 were false negatives. Only 18% (2/11) of patients with failed SNB had evidence of nodal metastases on completion axillary clearance. A total of 83 positive SNs were removed from 64 patients. Radioisotope count in the SNs decreased with increasing PR of the SNs by tumor (p=0.005). 30% (24) of the nodes removed were not hot (counts<10 times the background count). The mean PR by tumor of these nodes was 55% (SD 36) as compared to 33% (SD 33) for hot nodes (p=0.009). 20% (16/81) of the positive SNs showed EI. 69% (11) of nodes with EI were not hot (radioisotope count ratio <10) and would not be localised if the radioisotope was used alone. SNs with EI had a lower radioisotope count compared to SNs without EI (p<0.0001). The mean PR by tumor of nodes with EI was 70% (SD 26) compared to 32% (SD 33) of nodes without EI. This shows that extranodal growth of the tumor would occur once the node is >50% replaced with tumor. There was no correlation between radioisotope uptake and size of metastasis in the SN. There was no correlation between blue dye uptake and tumor burden in the positive SN. Conclusion: In an individual SN, the PR by tumor and EI are markers of lymphatic obstruction and significantly associated with reduced radioisotope uptake. These results suggest that >50% replacement of the node by tumor will compromise the lymphatic flow and may lead to failed localisation of the node if the radioisotope is used alone. However, the SN tumor burden does not affect blue dye uptake. This result provides an argument for using a combination of blue dye and radioisotope for SN biopsy. No significant financial relationships to disclose.
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Pan, Wu Min. "Dynamic Update Mechanism in Wireless Sensor Networks." Applied Mechanics and Materials 526 (February 2014): 267–72. http://dx.doi.org/10.4028/www.scientific.net/amm.526.267.
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Many researches use diff environmental conditions or application requirements in WSN. In the default Deluge mechanism, it will recover a sensor node from an updating error by reloading the stored full image again or waiting for the host machine to retransmit the full image again. This strategy is easy to implement and intuitive, but replacing the current executing image by retransmitting a full image file again is resource-consuming. To avoid retransmitting the full image when performing recovery, at the time when diff-based updating procedures have been finished, sensor nodes using our recovery mechanisms will backup the received patch files (i.e. diff script) in flash memory. Our mechanisms would effectively utilize flash memory space to store several backup patch files. When recovery is needed, our mechanismswould incrementally recover a failed node by patching up the system with each of the backup patch files. In the design of our recovery mechanisms, the failed sensor node will first try its best to recover itself without the assistance of the host machine, in order to avoid affecting the operations of other normal nodes when performing recovery procedures. Thus, compared with the full image replacement strategy, our mechanisms can save many computing resources.
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Huang, Yajing, and Feng Chen. "Community Structure and Systemic Risk of Bank Correlation Networks Based on the U.S. Financial Crisis in 2008." Algorithms 14, no. 6 (May 22, 2021): 162. http://dx.doi.org/10.3390/a14060162.
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This paper studies the community structure of the bank correlation network in the financial system and analyzes the systemic risk of the community sub-networks. Based on the balance sheet data of U.S. commercial banks from 2008, we establish a bank correlation network for each state according to the banks’ investment portfolio ratio. First, we analyze the community structure of each bank’s correlation network and verify the effectiveness of the community division from the point of view of the importance of nodes. Then, combining the data of failed banks after the 2008 financial crisis, we find that for small communities, the financial systemic risk will appear to have obvious volatility, and it is quite likely to reach an extremely high level. With the increase in the number of nodes in the community, systemic risk will tend towards a stable and low level. Furthermore, if only communities with failed banks are considered, the regression analysis shows that systemic risk and the size of the community almost follow a power law distribution trend. These results reveal the importance of supervising the banking system at the level of community sub-networks, which has certain guiding significance for the stability of the financial system.
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GORAYA, MAJOR SINGH, and LAKHWINDER KAUR. "FAULT TOLERANCE TASK EXECUTION THROUGH COOPERATIVE COMPUTING IN GRID." Parallel Processing Letters 23, no. 01 (March 2013): 1350003. http://dx.doi.org/10.1142/s0129626413500035.
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To achieve fault tolerant task execution in grid, cooperative computing system (CCS) is proposed in this paper. Grid resources with similar statistical characteristics constitute the computing nodes in CCS. CCS executes the allocated task, considered as its primary task, by organizing the computing nodes as active and active-standby. At a moment of time, one of the node acts as active node to execute the task whereas rest of the nodes act as active-standby to provide execution backup to the task. Computing nodes in CCS may fail during task execution due to the failure/exit of their corresponding resources. To maintain the fault tolerant ability of CCS, a failed node is repaired dynamically by replacing its corresponding resource with alternative matching resource from grid. The number of computing nodes in CCS is decided by optimizing the service reliability with respect to the execution overhead of the primary task. Resource usage is optimized in CCS by overloading the primary task at each active-standby node with a low priority secondary task. Active-standby nodes execute their low priority secondary tasks concurrently to providing execution backup to the primary task. Service reliability, system throughput and task delay is observed in the simulation experiments to explore the fault tolerant ability of CCS. A task set of 500 grid tasks is repeatedly executed by varying task duration and rate of resource failure. Simulation results show that CCS outperforms the existing fault tolerant approaches being used in grid. In CCS, fault tolerant task execution is achieved without compromising on account of resource utilization as well.
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WANG, JIAN-WEI, LI-LI RONG, and LIANG ZHANG. "EFFECT OF ATTACK ON SCALE-FREE NETWORKS DUE TO CASCADING FAILURE." Modern Physics Letters B 23, no. 12 (May 20, 2009): 1577–87. http://dx.doi.org/10.1142/s0217984909019557.
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In this paper, based on the local preferential redistribution rule of the load after removing a node, we propose a cascading model and explore cascading failures on scale-free networks. Assuming that a failed node leads only to a redistribution of the load passing through it to its neighboring nodes, we study the response of scale-free networks subject to attacks on nodes. The network robustness against cascading failures is quantitatively measured by the critical threshold Tc, at which a phase transition occurs from normal state to collapse. For each case of attacks on nodes, four different attack strategies are used: removal by the descending order of the degree, attack by the ascending order of the degree, random removal of breakdown, and removal by the ascending order of the average degree of neighboring nodes of a broken node. Compared with the previous result, i.e. the robust-yet-fragile property of scale-free networks on random failures of nodes and intentional attacks, our cascading model has totally different and interesting results. On the one hand, as unexpected, choosing the node with the lowest degree is more efficient than the one with the highest degree when α < 1, which is a tunable parameter in our model. On the other hand, the robustness against cascading failures and the harm order of four attack strategies strongly depends on the parameter α. These results may be very helpful for real-life networks to protect the key nodes and avoid cascading-failure-induced disasters.
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Evans, Michael R., Harold F. Wilkins, and Wesley P. Hackett. "Meristem Ontogenetic Age as the Controlling Factor in Long-day Floral Initiation in Poinsettia." Journal of the American Society for Horticultural Science 117, no. 6 (November 1992): 961–65. http://dx.doi.org/10.21273/jashs.117.6.961.
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The poinsettia [Euphorbia pulcherrima (Willd. ex. Klotzsch)] is a short-day plant (SDP) for floral initiation that will also initiate floral structures (cyathia) under long days (LD) after the apical meristem produces a cultivar-dependent number of nodes (long-day node number). Leaf removal, root restriction, and air layering failed to affect the long-day node number (LDNN) of the apical meristem. Repeated rooting of shoots, which resulted in the removal of nodes, did not affect the total number of nodes initiated by the apical meristem before floral initiation, although the number of nodes intact on the plant at the time of floral initiation was reduced. Reciprocal grafting of axillary buds of `Eckespoint Lilo' and `Gutbier V-14 Glory' plants did not affect the LDNN of the grafted meristem since the LDNN was the same as for nongrafted buds of the same cultivar. Further, grafting axillary buds from different positions along the main axis that differed in LDNN did not affect the LDNN of the grafted meristems. On the basis of these results, it was concluded that LD floral initiation in poinsettia is a function of the ontogenetic age of the meristem and that the LDNN represents a critical ontogenetic age for floral initiation to occur under LD.
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Pappa, Kalliopi I., Alexandros Rodolakis, Ioanna Christodoulou, Maria Gazouli, Sofia Markaki, Aris Antsaklis, and Nicholas P. Anagnou. "Comparative Assessment of Lymph Node Micrometastasis in Cervical, Endometrial and Vulvar Cancer: Insights on the Real Time qRT-PCR Approach versus Immunohistochemistry, Employing Dual Molecular Markers." BioMed Research International 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/187684.
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To address the value of qRT-PCR and IHC in accurately detecting lymph node micrometastasis in gynecological cancer, we performed a systematic approach, using a set of dual molecular tumor-specific markers such as cytokeratin 19 (CK19) and carbonic anhydrase 9 (CA9), in a series of 46 patients (19 with cervical cancer, 18 with endometrial cancer, and 9 with vulvar cancer). A total of 1281 lymph nodes were analyzed and 28 were found positive by histopathology. Following this documentation, 82 lymph nodes, 11 positive and 71 negative, were randomly selected and further analyzed both by IHC and qRT-PCR for CK19 and CA9 expression. All 11 (100%) expressed CK19 by IHC, while only 6 (54.5%) expressed CA9. On the contrary, all the histologically negative for micrometastases lymph nodes were also negative by IHC analysis for both markers. The comparative diagnostic efficacy of the two markers using qRT-PCR, however, disclosed that the analysis of the same aliquots of the 82 lymph nodes led to 100% specificity for the CK19 biomarker, while, in contrast, CA9 failed to recapitulate a similar pattern. These data suggest that qRT-PCR exhibits a better diagnostic accuracy compared to IHC, while CK19 displays a consistent pattern of detection compared to CA9.
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Keykhosravi, Davood, and Ali Hosseinalipour. "New Fault-Tolerant Hierarchical Routing Protocol for WSNs." Advanced Materials Research 433-440 (January 2012): 3223–29. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.3223.
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Clustering in wireless sensor networks is one of the crucial methods for increasing of network lifetime. There are many algorithms for clustering. One of the cluster based algorithm in wireless sensor networks is LEACH algorithm. In this paper we proposed a new clustering method for increasing of network lifetime. In proposed method Clustering is done symmetrically and the best node with respect to remained energy and distance of other nodes in comparing with each that selected as a cluster head. Although in this protocol we didn’t use GPS but we could find geographical position nodes so easily. However, failures in higher level of hierarchy e.g. cluster-head cause more damage to the system because they also limit accessibility to the nodes that are under their supervision. In this paper we propose an efficient mechanism to recover sensors from a failed cluster. In this performance of the proposed algorithm via computer simulation was evaluated and compared with other clustering algorithms. The simulation results show the high performance of the proposed clustering algorithm.
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Long, Guo Qing, and Xiao Ping Zhu. "Cooperative Area Coverage Reconnaissance Method for Multi-UAV System." Advanced Materials Research 383-390 (November 2011): 4141–46. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.4141.
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Aiming to find a solution, the method of cooperative area coverage reconnaissance for Multi-UAV system is proposed by combining centralized preplanning with distributed partial online replanning. In the preplanning, grid disintegration is applied to divide the area to be reconnoitered into task sequence of nodes and fuzzy C-means clustering algorithm is applied to conduct space distribution of task nodes; the online partial replanning is that the left UAVs automatically complete the unfinished task of the failed UAV, using the membership matrix got by clustering algorithm as a unified standard, which ensures that so long as one UAV does not fail, the reconnaissance task can be normally carried on. The simulation results show that this method, simple yet with a high robustness, can effectively solve the problem of multi-UAV cooperative area coverage reconnaissance.
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Liang, Wen Juan, and Ying Du. "Cyclic Structure in Regenerating Codes." Applied Mechanics and Materials 539 (July 2014): 416–19. http://dx.doi.org/10.4028/www.scientific.net/amm.539.416.
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Regenerating codes are a class of erasure codes for distributed storage. The use of regenerating codes not only improves reliability of distributed storage systems, but also minimizes repairing bandwidth when storage nodes failed and need to be repaired. In this paper, we investigate the cyclic structure of hybrid regenerating codes which each node has two fragments with the first fragment stores original message and the second fragment stores parity message. A fast repairing algorithm is also proposed.
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Xu, Zu Ming, and Xiong Fu. "A Study on Fault Model and Fault-Tolerant Routing for Sensor Networks." Applied Mechanics and Materials 182-183 (June 2012): 1265–69. http://dx.doi.org/10.4028/www.scientific.net/amm.182-183.1265.
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Wireless sensor networks require energy-efficient and robust routingprotocols. Most routing protocols for sensor networks try to extendnetwork lifetime by minimizing the energy consumption, but have not taken the network reliability into account. In this paper, we analyze the fault models and propose an ENergy-aware FAult-tolerantRouting scheme, termed as ENFAR. Firstly a link-based uniform fault model is presented, and we adopt a cross-layer design to measurethe transmission delay so as to detect the failed nodes.
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Kabansky, Alexander, Glenn Westwood, Samantha Tan, Frederic Kovacs, David Lou, Joe Han, Gerardo Delgadino, and H. W. Chang. "Optimization of Cu/Low-k Dual Damascene Post-Etch Residue and TiN Hard Mask Removal." Solid State Phenomena 255 (September 2016): 237–41. http://dx.doi.org/10.4028/www.scientific.net/ssp.255.237.
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For advanced technology nodes TiN hard mask integration into Cu/low-k via/trench DD process requires the mask to be fully stripped after DD etching. The one-step H2O2 containing wet chemical clean aiming to removing TiN mask often failed to simultaneously clean etch residue. We developed more reliable two-step wet chemical process combining a solvent-based post-etch residue clean followed by a solvent/H2O2 mixture strip for TiN mask removal. Bath lifetime optimization was also demonstrated.
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Settle, Brett, David Otasek, John H. Morris, and Barry Demchak. "Copycat Layout: Network layout alignment via Cytoscape Automation." F1000Research 7 (June 21, 2018): 822. http://dx.doi.org/10.12688/f1000research.15144.1.
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The copycatLayout app is a network-based visual differential analysis tool that improves upon the existing layoutSaver app and is delivered pre-installed with Cytoscape, beginning with v3.6.0. LayoutSaver cloned a network layout by mapping node locations from one network to another based on node attribute values, but failed to clone view scale and location, and provided no means of identifying which nodes were successfully mapped between networks. Copycat addresses these issues and provides additional layout options. With the advent of Cytoscape Automation (packaged in Cytoscape v3.6.0), researchers can utilize the Copycat layout and its output in workflows written in their language of choice by using only a few simple REST calls. Copycat enables researchers to visually compare groups of homologous genes, generate network comparison images for publications, and quickly identify differences between similar networks at a glance without leaving their script. With a few extra REST calls, scripts can discover nodes present in one network but not in the other, which can feed into more complex analyses (e.g., modifying mismatched nodes based on new data, then re-running the layout to highlight additional network changes).
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Settle, Brett, David Otasek, John H. Morris, and Barry Demchak. "Copycat Layout: Network layout alignment via Cytoscape Automation." F1000Research 7 (August 10, 2018): 822. http://dx.doi.org/10.12688/f1000research.15144.2.
Full textAbstract:
The copycatLayout app is a network-based visual differential analysis tool that improves upon the existing layoutSaver app and is delivered pre-installed with Cytoscape, beginning with v3.6.0. LayoutSaver cloned a network layout by mapping node locations from one network to another based on node attribute values, but failed to clone view scale and location, and provided no means of identifying which nodes were successfully mapped between networks. Copycat addresses these issues and provides additional layout options. With the advent of Cytoscape Automation (packaged in Cytoscape v3.6.0), researchers can utilize the Copycat layout and its output in workflows written in their language of choice by using only a few simple REST calls. Copycat enables researchers to visually compare groups of homologous genes, generate network comparison images for publications, and quickly identify differences between similar networks at a glance without leaving their script. With a few extra REST calls, scripts can discover nodes present in one network but not in the other, which can feed into more complex analyses (e.g., modifying mismatched nodes based on new data, then re-running the layout to highlight additional network changes).
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Dutt, Suparna, Joerg Ermann, Diane Tseng, Yin Ping Liu, Tracy I. George, C. Garrison Fathman, and Samuel Strober. "L-selectin and β7 integrin on donor CD4 T cells are required for the early migration to host mesenteric lymph nodes and acute colitis of graft-versus-host disease." Blood 106, no. 12 (December 1, 2005): 4009–15. http://dx.doi.org/10.1182/blood-2005-06-2339.
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The homing receptors L-selectin and α4β7 integrin facilitate entry of T cells into the gut-associated organized lymphoid tissues such as the mesenteric lymph nodes and Peyer patches. We studied the impact of inactivation of genes encoding these receptors on the ability of purified donor CD4+ T cells to induce acute lethal graft-versus-host disease (GVHD) associated with severe colitis in irradiated major histocompatibility complex (MHC)–mismatched mice. Whereas lack of expression of a single receptor had no significant impact on the severity of colitis and GVHD, the lack of expression of both receptors markedly ameliorated colitis and early deaths observed with wild-type (WT) T cells. The changes in colitis and GVHD were reflected in a marked reduction in the early accumulation of donor T cells in the mesenteric lymph nodes and subsequently in the colon. The purified WT donor CD4+ T cells did not accumulate early in the Peyer patches and failed to induce acute injury to the small intestine. In conclusion, the combination of CD62L and β7 integrin is required to induce acute colitis and facilitate entry of CD4+ donor T cells in the mesenteric nodes associated with lethal GVHD in allogeneic hosts.
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Helana, Temesgen Mengistu, and Alazar Merdekios Keba. "Enhancing the Performance of Dynamic Source Routing Protocol by Modifying the Algorithm in Mobile ad-hoc Network." International Journal of Innovative Science and Research Technology 5, no. 5 (June 27, 2020): 1960–64. http://dx.doi.org/10.38124/ijisrt20may880.
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In our day-to-day life, wireless technology plays a great role, because users move from place to place across the globe, it’s important to think about the type of network we can deploy quickly. Collection of two or more node forms A mobile ad-hoc network (MANET) without the aid of any centralized infrastructure. There are independent nodes that communicate without a wire in a mobile ad hoc network. Due to the behavior of nodes in MANET the time when node joining/leaving the network is unknown. This study focuses on improve performance of DSR protocol affected due to selfish nodes. So, identify path without any selfish node is the main issue for delivering a packet by selecting a reserved path. The algorithm counts the number of failed route request messages to aware the selfish node that causes failure on NS-2 simulator tools. The node is assigned to indicating the selfishness status of the node during route discovery. In this study the researcher conducts performance evaluation of existing DSR and modified one is assessed by using packet delivery ratio, and endto-end delay metrics and achieved very good result.
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Jiang, Zhong-Yuan, and Jian-Feng Ma. "An efficient local cascade defense method in complex networks." International Journal of Modern Physics C 28, no. 03 (March 2017): 1750031. http://dx.doi.org/10.1142/s0129183117500310.
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Cascading failures in networked systems often lead to catastrophic consequence. Defending cascading failure propagation by employing local load redistribution method is an efficient way. Given initial load of every node, the key of improving network robustness against cascading failures is to maximally defend cascade propagation with minimum total extra capacity of all nodes. With finite total extra capacity of all nodes, we first discuss three general extra capacity distributions including degree-based distribution (DD), average distribution (AD) and random distribution (RD). To sufficiently use the total spare capacity (SC) of all neighboring nodes of a failed node, then we propose a novel SC-based local load redistribution mechanism to improve the cascade defense ability of network. We investigate the network robustness against cascading failures induced by a single node failure under the three extra capacity distributions in both scale-free networks and random networks. Compared with the degree-based (DB) local load redistribution method, our SC method achieves higher robustness under all of the three extra capacity distributions. The extensive simulation results can well confirm the effectiveness of the SC local load redistribution method.
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Lai, Cheng Yu, and Xiao Guang Fu. "Research of Hybrid Congestion Control Mechanism." Advanced Materials Research 426 (January 2012): 275–78. http://dx.doi.org/10.4028/www.scientific.net/amr.426.275.
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In wireless sensor networks, congestion causes overall channel quality to degrade and loss rates to raise, leads to buffer drops and increased delays, and tends to be grossly unfair toward nodes whose data has to traverse a larger number of radio hops. Hybrid congestion control mechanisms relieve the congestion by creating the new path; when establishment of a new path is failed, fairness aggregate mechanisms limits forward rate, ensures that each source node sends data fairly. Based on energy-saving, algorithms for mild congestion have been improved.
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Simões, LaVoy, and Dean. "Effects of Regulatory T Cell Depletion on NK Cell Responses against Listeria monocytogenes in Feline Immunodeficiency Virus Infected Cats." Viruses 11, no. 11 (October 24, 2019): 984. http://dx.doi.org/10.3390/v11110984.
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Regulatory T cells (Treg) are key players in the maintenance of peripheral tolerance, preventing autoimmune diseases and restraining chronic inflammatory diseases. Evidence suggests Treg cells and NK cells have important roles in feline immunodeficiency virus (FIV) pathogenesis; however, in vivo studies investigating the interplay between these two cell populations are lacking. We previously described innate immune defects in FIV-infected cats characterized by cytokine deficits and impaired natural killer cell (NK) and NK T cell (NKT) functions. In this study, we investigated whether in vivo Treg depletion by treatment with an anti-feline CD25 monoclonal antibody would improve the innate immune response against subcutaneous challenge with Listeria monocytogenes (Lm). Treg depletion resulted in an increased overall number of cells in Lm-draining lymph nodes and increased proliferation of NK and NKT cells in FIV-infected cats. Treg depletion did not normalize expression of perforin or granzyme A by NK and NKT cells, nor did Treg depletion result in improved clearance of Lm. Thus, despite the quantitative improvements in the NK and NKT cell responses to Lm, there was no functional improvement in the early control of Lm. CD1a+ dendritic cell percentages in the lymph nodes of FIV-infected cats were lower than in specific-pathogen-free control cats and failed to upregulate CD80 even when Treg were depleted. Taken together, Treg depletion failed to improve the innate immune response of FIV-infected cats against Lm and this may be due to dendritic cell dysfunction.