A fundamental problem that confronts peer-to-peer applications is to efficiently locate the node that stores a particular data item. This paper presents Chord, a distributed lookup protocol that addresses this problem. Chord provides support for just one operation: given a key, it maps the key onto a node. Data location can be easily implemented on top of Chord by associating a key with each data item, and storing the key/data item pair at the node to which the key maps. Chord adapts efficiently as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from theoretical analysis, simulations, and experiments show that Chord is scalable, with communication cost and the state maintained by each node scaling logarithmically with the number of Chord nodes.

Chord: A scalable peer-to-peer lookup service for internet applications

This paper presents the design and evaluation of Pastry, a scalable, distributed object location and routing substrate for wide-area peer-to-peer ap- plications. Pastry performs application-level routing and object location in a po- tentially very large overlay network of nodes connected via the Internet. It can be used to support a variety of peer-to-peer applications, including global data storage, data sharing, group communication and naming. Each node in the Pastry network has a unique identifier (nodeId). When presented with a message and a key, a Pastry node efficiently routes the message to the node with a nodeId that is numerically closest to the key, among all currently live Pastry nodes. Each Pastry node keeps track of its immediate neighbors in the nodeId space, and notifies applications of new node arrivals, node failures and recoveries. Pastry takes into account network locality; it seeks to minimize the distance messages travel, according to a to scalar proximity metric like the number of IP routing hops. Pastry is completely decentralized, scalable, and self-organizing; it automatically adapts to the arrival, departure and failure of nodes. Experimental results obtained with a prototype implementation on an emulated network of up to 100,000 nodes confirm Pastry's scalability and efficiency, its ability to self-organize and adapt to node failures, and its good network locality properties.

/pdf/pastry-scalable-decentralized-object-location-and-routing-1u2equbbbp.pdf

Pastry: Scalable, Decentralized Object Location, and Routing for Large-Scale Peer-to-Peer Systems

Hash tables - which map "keys" onto "values" - are an essential building block in modern software systems. We believe a similar functionality would be equally valuable to large distributed systems. In this paper, we introduce the concept of a Content-Addressable Network (CAN) as a distributed infrastructure that provides hash table-like functionality on Internet-like scales. The CAN is scalable, fault-tolerant and completely self-organizing, and we demonstrate its scalability, robustness and low-latency properties through simulation.

https://www.cs.sjtu.edu.cn/~gchen/course/acn/Reading/CAN.pdf

A scalable content-addressable network

A review of the geologic history of the Himalayan-Tibetan orogen suggests that at least 1400 km of north-south shortening has been absorbed by the orogen since the onset of the Indo-Asian collision at about 70 Ma. Significant crustal shortening, which leads to eventual construction of the Cenozoic Tibetan plateau, began more or less synchronously in the Eocene (50–40 Ma) in the Tethyan Himalaya in the south, and in the Kunlun Shan and the Qilian Shan some 1000–1400 km in the north. The Paleozoic and Mesozoic tectonic histories in the Himalayan-Tibetan orogen exerted a strong control over the Cenozoic strain history and strain distribution. The presence of widespread Triassic flysch complex in the Songpan-Ganzi-Hoh Xil and the Qiangtang terranes can be spatially correlated with Cenozoic volcanism and thrusting in central Tibet. The marked difference in seismic properties of the crust and the upper mantle between southern and central Tibet is a manifestation of both Mesozoic and Cenozoic tectonics. The form...

Geologic Evolution of the Himalayan-Tibetan Orogen

Reliability at massive scale is one of the biggest challenges we face at Amazon.com, one of the largest e-commerce operations in the world; even the slightest outage has significant financial consequences and impacts customer trust. The Amazon.com platform, which provides services for many web sites worldwide, is implemented on top of an infrastructure of tens of thousands of servers and network components located in many datacenters around the world. At this scale, small and large components fail continuously and the way persistent state is managed in the face of these failures drives the reliability and scalability of the software systems.This paper presents the design and implementation of Dynamo, a highly available key-value storage system that some of Amazon's core services use to provide an "always-on" experience. To achieve this level of availability, Dynamo sacrifices consistency under certain failure scenarios. It makes extensive use of object versioning and application-assisted conflict resolution in a manner that provides a novel interface for developers to use.

/pdf/dynamo-amazon-s-highly-available-key-value-store-2ozfk43ou4.pdf

Dynamo: amazon's highly available key-value store

Mobile authentication is a fundamental factor in the protection of user’s private resources. In recent years, motion sensor-based biometric authentication has been widely used for privacy-preserving. However, it faces with the problems including low data collection efficiency, insufficient authentication scenario coverage rate, weak de-noising ability, and poor robustness of models, rendering existing methods difficult to meet the security, privacy, and usability requirements jointly in the real-world scenario. To overcome these difficulties, we propose a system called EspialCog, which is able to 1) collect the sensor data embedded in mobile devices self-adaptively, unobtrusively and efficiently through the evolutionary stable participation game mechanism (ESPGM) with a high scenario coverage rate; 2) minimize noise from collected data by analyzing three types of abnormalities; and 3) authenticate the ownership of mobile devices in real-time by adopting optimized LSTM model with an enhanced stochastic gradient descent (SGD) algorithm. The simulation experiment on 6000 users shows that the efficiency and coverage rates increase dramatically by deploying our ESPGM. Moreover, we conduct experiments on a large-scale real-world noisy dataset with 1513 users and two other small pure real-world datasets. The experimental results show the high accuracy and favorable robustness of EspialCog in the noisy environment.

ESPIALCOG: General, Efficient and Robust Mobile User Implicit Authentication in Noisy Environment

In recent years, network function virtualization (NFV) has drawn considerable attention due to its potential for service agility and low total cost of ownership. As the core of an NFV implementation, security issues in the management and control platform must be comprehensively addressed—from architectural concept to deployment. In this article, we first analyze the state of the security architecture based on ETSI-NFV, and then propose useful security practices for an NFV-based management and control ecosystem. To encourage future research, we also identify the ongoing research challenges and open security issues relevant to the NFV.

State of the Art and Research Challenges in the Security Technologies of Network Function Virtualization

Embodiments of the present invention disclose a method and an apparatus for transmitting data in a multiple-antenna system, which are applied in a transmit diversity mode. The method includes: in a data transmission period, determining, according to transmission quality of the system, the number of antennas to be turned off and turning-off time; and in the turning-off time, turning off the determined number of antennas, turning on remaining antennas other than the antennas that are turned off, and transmitting, through the remaining antennas, the data to be transmitted; and during the remaining time of the data transmission period excluding the turning-off time, turning on all antennas and transmitting, through all the antennas, the data to be transmitted. According to the embodiments of the present invention, power consumption may be decreased while at the same time dynamic transmission performance of the system is considered, decreasing implementation complexity.

Method and apparatus for transmitting data in multiple-antenna system

The past decade has become an important strategy in precision medicine for the targeted therapy of many diseases, expecially various types of cancer. As a promising targeted element, nucleic acid aptamers are single-stranded functional oligonucleotides which have specific abilities to bind with various target molecules ranging from small molecules to entire organisms. They are often named ‘chemical antibody’ and have aroused extensive interest in diverse clinical studies on account of their advantages, such as considerable biostability, versatile chemical modification, low immunogenicity and quick tissue penetration. Thus, aptamer-embedded drug delivery systems offer an unprecedented opportunity in bioanalysis and biomedicine. In this short review, we endeavor to discuss the recent advances in aptamer-based targeted drug delivery platforms for cancer therapy. Some perspectives on the advantages, challenges and opportunities are also presented.

https://www.frontiersin.org/articles/10.3389/fbioe.2022.972933/pdf

Recent advances in aptamer-based targeted drug delivery systems for cancer therapy

We propose to use second order Reed-Muller (RM) sequence for user identification in 5G grant-free access. The benefits of RM sequences mainly lie in two folds, (i) support of much larger user space, hence lower collision probability and (ii) lower detection complexity. These two features are essential to meet the massive connectivity ($10^7$ links/km$^2$), ultra-reliable and low-latency requirements in 5G, e.g., one-shot transmission ($\leq 1$ms) with $\leq 10^{-4}$ packet error rate. However, the non-orthogonality introduced during sequence space expansion leads to worse detection performance. In this paper, we propose a noise-resilient detection algorithm along with a layered sequence construction to meet the harsh requirements. Link-level simulations in both narrow-band and OFDM-based scenarios show that RM sequences are suitable for 5G.

Yan Chen

Papers

ESPIALCOG: General, Efficient and Robust Mobile User Implicit Authentication in Noisy Environment

State of the Art and Research Challenges in the Security Technologies of Network Function Virtualization

Method and apparatus for transmitting data in multiple-antenna system

Recent advances in aptamer-based targeted drug delivery systems for cancer therapy

Reed-Muller Sequences for 5G Grant-free Massive Access