Convergence of Probability Measures. By P. Billingsley. Chichester, Sussex, Wiley, 1968. xii, 253 p. 9 1/4“. 117s.

Convergence of Probability Measures

Social Network Analysis

The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to predefined policies, and to reconfigure it to respond to faults, load, and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-defined networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns, introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper, we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound application programming interfaces (APIs), network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms—with a focus on aspects such as resiliency, scalability, performance, security, and dependability—as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment.

https://publications.uni.lu/bitstream/10993/20596/1/survey_on_SDN.pdf

Software-Defined Networking: A Comprehensive Survey

Infectious Diseases Society of America.

The structure and dynamics of multilayer networks

NetFlow and IPFIX raw flow captures are insightful yet, due to their large volume, challenging to timely analyze and query. In particular, if these captures span long time periods or are collected at remote locations, storing or transferring them for analysis becomes increasingly expensive. Enabling efficient execution of a large range of queries over flow captures while reducing storage and transfer volume requires working with mergeable succinct summaries that capture the most essential features of flows dynamically. However, the problem of building such structures is yet unmet. In this work, we introduce a self-adjusting data structure of generalized flows, called Flowtree, that (1) reduces the storage requirements by more than 95% while providing highly accurate answers for popular hierarchical flows, (2) minimizes transfer cost of flow summaries, and (3) supports several operators with distributed execution and summarization across time and multiple sites. The evaluation of our solution on different network traces confirms that Flowtree can accurately and promptly answer questions about flows using different feature sets.

/pdf/flowtree-enabling-distributed-flow-summarization-at-scale-2forem238i.pdf

Flowtree: Enabling Distributed Flow Summarization at Scale

Wide-Area CloudNet Migrations Under Latency and Resource Constraints

Simple Summary PD-L1 plays a crucial role in the immune responses against cancer. Only around 30% of cancer patients respond to an anti-PD-L1 immune checkpoint inhibitor therapy. Noninvasive molecular imaging techniques such as positron emission tomography (PET) would allow identification of patients likely to respond. Here we report on the synthesis of nine PET radioligands targeting PD-L1, based on small-molecule inhibitors. We introduced a chelator for radiolabeling and water-soluble groups to aim for clearance through the kidneys. The compounds showed binding affinities toward PD-L1 in the lower nanomolar range and stability in vitro. Mouse experiments showed moderate accumulation in tumor tissue but mainly clearance through the liver. Additionally, the compounds showed unexpected long circulation times due to strong binding to albumin in blood. Nevertheless, our compounds are a starting point for further development of PD-L1 small molecule PET radiotracer to support therapy decisions. Abstract Noninvasive molecular imaging of the PD-1/PD-L1 immune checkpoint is of high clinical relevance for patient stratification and therapy monitoring in cancer patients. Here we report nine small-molecule PD-L1 radiotracers with solubilizing sulfonic acids and a linker–chelator system, designed by molecular docking experiments and synthesized according to a new, convergent synthetic strategy. Binding affinities were determined both in cellular saturation and real-time binding assay (LigandTracer), revealing dissociation constants in the single digit nanomolar range. Incubation in human serum and liver microsomes proved in vitro stability of these compounds. Small animal PET/CT imaging, in mice bearing PD-L1 overexpressing and PD-L1 negative tumors, showed moderate to low uptake. All compounds were cleared primarily through the hepatobiliary excretion route and showed a long circulation time. The latter was attributed to strong blood albumin binding effects, discovered during our binding experiments. Taken together, these compounds are a promising starting point for further development of a new class of PD-L1 targeting radiotracers.

/pdf/design-and-biological-evaluation-of-small-molecule-pet-bvggps9b.pdf

Design and Biological Evaluation of Small-Molecule PET-Tracers for Imaging of Programmed Death Ligand 1

Silicon nanowire sensors have demonstrated outstanding utility in biosensing, especially for small biomolecules at extremely low concentrations. However, the sensor is less commonly applied in whole-cell monitoring, such as CAR T-cell counting during cancer treatment. The patient&rsquo;s T-cells are modified to express chimeric antigen receptors (CAR), targeting specific tumor cells in CAR T-cell treatment. Therefore, the CAR T-cell level in blood is an essential parameter when it comes to determining the immune system&rsquo;s reactivity to fight cancer cells. Although nanosensors are typically beneficial for early cancer diagnosis and detection, we want to expand their application and explore their usage in cancer treatment monitoring and development. Our previous works showed promising results of using nanosensors to find the most effective immunotherapy. In this work, we study the response of silicon nanowire field-effect transistors (SiNW FET) to the binding of CAR T-cells and discuss the benefits and limitations of the sensors in cell monitoring. The SiNW FETs fabricated in a top-down manner showed superior sensitivity to IgG antibodies sensing in our previous study. A peptide with a high affinity to the designed CAR T-cells immobilized on SiNW FETs to detect the cell binding. We observed distinguished signals following the number of cells binding to the sensing area. The results pave the way for using nanosensors in monitoring cancer treatment, yet they suggest some room for improvement. 

/pdf/cell-counting-in-silicon-nanosensor-for-car-t-cell-therapy-23ou7npx.pdf

Cell Counting in Silicon Nanosensor for CAR T-Cell Therapy Monitoring

Transport protocols use port numbers to allow connection multiplexing on Internet hosts. TCP as well as UDP, the two most widely used transport protocols, have limitations on what constitutes a valid and invalid port number. One example of an invalid port number for these protocols is port 0. In this work, we present preliminary results from analyzing port 0 traffic at a large European IXP. In one week of traffic we find 74GB port 0 traffic. The vast majority of this traffic has both source and destination ports set to 0, suggesting scanning or reconnaissance as its root cause. Our analysis also shows that more than half of all port 0 traffic is targeted to just 18 ASes, whereas more than half of all traffic is originated by about 100 ASes, suggesting a more diverse set of source ASes.

https://pure.mpg.de/pubman/item/item_3219703_3/component/file_3219704/arXiv%3A2004.03653.pdf

Anja Feldmann

Papers

Flowtree: Enabling Distributed Flow Summarization at Scale

Wide-Area CloudNet Migrations Under Latency and Resource Constraints

Design and Biological Evaluation of Small-Molecule PET-Tracers for Imaging of Programmed Death Ligand 1

Cell Counting in Silicon Nanosensor for CAR T-Cell Therapy Monitoring

Reserved: Dissecting Internet Traffic on Port 0