3,135 research outputs found
Detectability Of Fuzzy Discrete Event Systems
Dynamic systems that can be modeled in terms of discrete states and a synchronous events are known as discrete event systems (DES). A DES is defined in terms of states, events, transition dynamics, and initial state. Knowing the system’s state is crucial in many applications for certain actions (events) to be taken. A DES system is considered a fuzzy discrete event system (FDES) if its states and events are vague in nature; for such systems, the system can be in more than one state at the same time with different degrees of possibility (membership). In this research we introduce a fuzzy discrete event system with constraints (FDESwC) and investigate its detectabilities. This research aims to address the gap in previous studies and extend existing definitions of detectability of DES to include the detectability in systems with substantial vagueness such as FDES. These definitions are first reformulated to introduce N-detectability for DES, which are further extended to define four main types of detectabilities for FDES: strong N-detectability, (weak) N-detectability, strong periodic N-detectability, and (weak) periodic N-detectability. We first partition the FDES into trajectories of a length dictated by the depth of the event’s string (length of the event sequence); each trajectory consists of a number of nodes, which are further investigated for detectability by examining them against the newly introduced certainty criterion. Matrix computation algorithms and fuzzy logic operations are adopted to calculate the state estimates based on the current state and the occurring events. Vehicle dynamics control example is used to demonstrate the practical aspect of developed theorems in real-world applications
FLEET: Butterfly Estimation from a Bipartite Graph Stream
We consider space-efficient single-pass estimation of the number of
butterflies, a fundamental bipartite graph motif, from a massive bipartite
graph stream where each edge represents a connection between entities in two
different partitions. We present a space lower bound for any streaming
algorithm that can estimate the number of butterflies accurately, as well as
FLEET, a suite of algorithms for accurately estimating the number of
butterflies in the graph stream. Estimates returned by the algorithms come with
provable guarantees on the approximation error, and experiments show good
tradeoffs between the space used and the accuracy of approximation. We also
present space-efficient algorithms for estimating the number of butterflies
within a sliding window of the most recent elements in the stream. While there
is a significant body of work on counting subgraphs such as triangles in a
unipartite graph stream, our work seems to be one of the few to tackle the case
of bipartite graph streams.Comment: This is the author's version of the work. It is posted here by
permission of ACM for your personal use. Not for redistribution. The
definitive version was published in Seyed-Vahid Sanei-Mehri, Yu Zhang, Ahmet
Erdem Sariyuce and Srikanta Tirthapura. "FLEET: Butterfly Estimation from a
Bipartite Graph Stream". The 28th ACM International Conference on Information
and Knowledge Managemen
INTERVAL INCLUSION COMPUTATION FOR THE SOLUTIONS OF THE BURGERS EQUATION
National Natural Science Foundation of China [10571146]In this paper we study the interval computation for the solutions of the Burgers equation. For the initial-boundary value problems of the Burgers equation by using the technique of the Green function, a new kind of interval method is proposed. Both algorithm and computational examples are given. Convergence is proved. From the results we see that this interval method can get a better solution with our corroboration
Multi-objective optimization based network control principles for identifying personalized drug targets with cancer
It is a big challenge to develop efficient models for identifying
personalized drug targets (PDTs) from high-dimensional personalized genomic
profile of individual patients. Recent structural network control principles
have introduced a new approach to discover PDTs by selecting an optimal set of
driver genes in personalized gene interaction network (PGIN). However, most of
current methods only focus on controlling the system through a minimum
driver-node set and ignore the existence of multiple candidate driver-node sets
for therapeutic drug target identification in PGIN. Therefore, this paper
proposed multi-objective optimization-based structural network control
principles (MONCP) by considering minimum driver nodes and maximum prior-known
drug-target information. To solve MONCP, a discrete multi-objective
optimization problem is formulated with many constrained variables, and a novel
evolutionary optimization model called LSCV-MCEA was developed by adapting a
multi-tasking framework and a rankings-based fitness function method. With
genomics data of patients with breast or lung cancer from The Cancer Genome
Atlas database, the effectiveness of LSCV-MCEA was validated. The experimental
results indicated that compared with other advanced methods, LSCV-MCEA can more
effectively identify PDTs with the highest Area Under the Curve score for
predicting clinically annotated combinatorial drugs. Meanwhile, LSCV-MCEA can
more effectively solve MONCP than other evolutionary optimization methods in
terms of algorithm convergence and diversity. Particularly, LSCV-MCEA can
efficiently detect disease signals for individual patients with BRCA cancer.
The study results show that multi-objective optimization can solve structural
network control principles effectively and offer a new perspective for
understanding tumor heterogeneity in cancer precision medicine.Comment: 15 pages, 8 figures; This work has been submitted to IEEE
Transactions on Evolutionary Computatio
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