424 research outputs found
Structural and functional studies on membrane fusion proteins-SNAREs
Membrane fusion is a ubiquitous and essential intracellular function. Membrane fusion is mediated by a protein superfamily known as N-ethymaleimide-sensitive fusion protein attachment protein receptors (SNAREs). From plant to mammal, there is a remarkable sequence similarity among the SNARE-family related to the conserved function of this family. The function of SNAREs has been proposed to be the key to membrane fusion as minimal fusion machinery. Depending on their distinct membrane distribution, SNAREs were classified into v (vesicle)-SNAREs and t (target)-SNAREs. It is widely believed that SNARE complex assembly by v- and t-SNAREs on opposite membranes offers the ultimate driving force for membrane fusion.;The purpose of this work is to investigate the structure dependent SNARE functions. Here we use biophysical methods of EPR (Electron paramagnetic resonance) to study the structure of SNARE proteins. Florescence lipid mixing assay is the biochemical method which is used to monitor SNAREs facilitated liposomes fusion in vitro. EPR study of SNARE assembly and v-SNARE membrane proximal region topology unravel that constitutive or regulated membrane fusion is determined by a protein structure difference. Yeast v-SNARE transmembrane domain (TMD) structure was modeled by the EPR method. The TMD of yeast v-SNARE half truncated mutant is designed from this structure. This mutant and the low SNAREs surface density lead to the discovery of membrane fusion intermediate state-hemifusion. Finally, lipid mixing assays help to identify the neuronal SNARE motif is the position to adopt the regulator of fast neuron transmitter release -SynaptotagminI for its function
An n/2 Byzantine node tolerate Blockchain Sharding approach
Traditional Blockchain Sharding approaches can only tolerate up to n/3 of
nodes being adversary because they rely on the hypergeometric distribution to
make a failure (an adversary does not have n/3 of nodes globally but can
manipulate the consensus of a Shard) hard to happen. The system must maintain a
large Shard size (the number of nodes inside a Shard) to sustain the low
failure probability so that only a small number of Shards may exist. In this
paper, we present a new approach of Blockchain Sharding that can withstand up
to n/2 of nodes being bad. We categorise the nodes into different classes, and
every Shard has a fixed number of nodes from different classes. We prove that
this design is much more secure than the traditional models (only have one
class) and the Shard size can be reduced significantly. In this way, many more
Shards can exist, and the transaction throughput can be largely increased. The
improved Blockchain Sharding approach is promising to serve as the foundation
for decentralised autonomous organisations and decentralised database
MWPoW: Multiple Winners Proof of Work Protocol, a decentralisation strengthened fast-confirm blockchain protocol
Blockchain mining should not be a game among power oligarchs. In this paper, we present the Multiple Winners Proof of Work Protocol (MWPoW), a mining-pool-like decentralised blockchain consensus protocol. MWPoW enables disadvantaged nodes which post only a small amount of calculation resource in the mining game to create blocks together and compete with power oligarchs without centralised representatives. A precise Support Rate of blocks can be determined through the mining process; the mechanism of the mainchain determination is therefore changed and has become faster and more straightforward. A method that periodically adjusts the block size and the block interval is introduced into MWPoW, which increases the system flexibility in the changes of network conditions and data flow. Experiments suggest, without lifting calculation and bandwidth requirements, MWPoW is more attractive to disadvantaged nodes due to its mostly increased reward expectation for disadvantaged nodes. The transaction pending time is shortened chiefly, and either the block interval or the block size can be adapted amid the changes of overall network conditions
Segment blockchain: a size reduced storage mechanism for blockchain
The exponential growth of the blockchain size has become a major contributing factor that hinders the decentralisation of blockchain and its potential implementations in data-heavy applications.
In this paper, we propose segment blockchain, an approach that segmentises blockchain and enables nodes to
only store a copy of one blockchain segment. We use PoW as a membership threshold to limit the number of
nodes taken by an Adversary—the Adversary can only gain at most n/2 of nodes in a network of n nodes when
it has 50% of the calculation power in the system (the Nakamoto blockchain security threshold). A segment
blockchain system fails when an Adversary stores all copies of a segment, because the Adversary can then
leave the system, causing a permanent loss of the segment. We theoretically prove that segment blockchain
can sustain a failure probability when the Adversary has no more than AD number of nodes and
every segment is stored by m number of nodes. The storage requirement is mostly shrunken compared to the
traditional design and therefore making the blockchain more suitable for data-heavy applications
Connecting Software Metrics across Versions to Predict Defects
Accurate software defect prediction could help software practitioners
allocate test resources to defect-prone modules effectively and efficiently. In
the last decades, much effort has been devoted to build accurate defect
prediction models, including developing quality defect predictors and modeling
techniques. However, current widely used defect predictors such as code metrics
and process metrics could not well describe how software modules change over
the project evolution, which we believe is important for defect prediction. In
order to deal with this problem, in this paper, we propose to use the
Historical Version Sequence of Metrics (HVSM) in continuous software versions
as defect predictors. Furthermore, we leverage Recurrent Neural Network (RNN),
a popular modeling technique, to take HVSM as the input to build software
prediction models. The experimental results show that, in most cases, the
proposed HVSM-based RNN model has a significantly better effort-aware ranking
effectiveness than the commonly used baseline models
Contract-connection:An efficient communication protocol for Distributed Ledger Technology
Distributed Ledger Technology (DLT) is promising to become the foundation of
many decentralised systems. However, the unbalanced and unregulated network
layout contributes to the inefficiency of DLT especially in the Internet of
Things (IoT) environments, where nodes connect to only a limited number of
peers. The data communication speed globally is unbalanced and does not live up
to the constraints of efficient real-time distributed systems. In this paper,
we introduce a new communication protocol, which enables nodes to calculate the
tradeoff between connecting/disconnecting a peer in a completely decentralised
manner. The network layout globally is continuously re-balancing and optimising
along with nodes adjusting their peers. This communication protocol weakened
the inequality of the communication network. The experiment suggests this
communication protocol is stable and efficient
On the Lp Gaussian Minkowski problem
Existence of symmetric (resp. asymmetric) solutions to the Gaussian
Minkowski problem for (resp. ) will be provided. Moreover,
existence and uniqueness of smooth solutions to the problem for will also
be proved without the restriction that the Gaussian volumes of convex bodies
are not less than one-second.Comment: arXiv admin note: text overlap with arXiv:2207.0693
Anchoring the value of cryptocurrency
A decade long thrive of cryptocurrency has shown its potential as a source of alternative-finance and the security and the robustness of the underpinning blockchain technology. However, most cryptocurrencies fail to show inimitability and their meanings in the real world. As a result, they usually start off as favourites but quickly become the outcasts of the digital asset market. The blockchain society attempts to anchor the value of cryptocurrency with real values by employing smart contracts and link it with computation resources and the digital-productivity that have value and demands in the real world. But their attempts have some undesirable effects due to a limited number of practical applications. This limitation is caused by the dilemma between high performance and decentralisation (universal joinability). The emerging of blockchain sharding models, however, has offered a possible solution to address this dilemma. In this paper, we explore a financial model for blockchain sharding that will build an active link between the value of cryptocurrency and computation resources as well as the market and labour behaviours. Our model can adjust the price of resources and the compensation for maintaining a system based on those behaviours. We anchor the value of cryptocurrency by the amount of computation resources participated in and give the cryptocurrency a meaning as the exchange between computation resources globally. Finally, we present a working example which, through financial regularities, regulates the behaviour of anonymous participants, also incents/discourages participation dynamically
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