4,614 research outputs found
Singleton-Optimal LRCs and Perfect LRCs via Cyclic and Constacyclic Codes
Locally repairable codes (LRCs) have emerged as an important coding scheme in
distributed storage systems (DSSs) with relatively low repair cost by accessing
fewer non-failure nodes. Theoretical bounds and optimal constructions of LRCs
have been widely investigated. Optimal LRCs via cyclic and constacyclic codes
provide significant benefit of elegant algebraic structure and efficient
encoding procedure. In this paper, we continue to consider the constructions of
optimal LRCs via cyclic and constacyclic codes with long code length.
Specifically, we first obtain two classes of -ary cyclic Singleton-optimal
-LRCs with length when and is
even, and length when and , respectively. To the best of our knowledge, this is the first
construction of -ary cyclic Singleton-optimal LRCs with length and
minimum distance . On the other hand, an LRC acheiving the
Hamming-type bound is called a perfect LRC. By using cyclic and constacyclic
codes, we construct two new families of -ary perfect LRCs with length
, minimum distance and locality
Solving multiple-criteria R&D project selection problems with a data-driven evidential reasoning rule
In this paper, a likelihood based evidence acquisition approach is proposed
to acquire evidence from experts'assessments as recorded in historical
datasets. Then a data-driven evidential reasoning rule based model is
introduced to R&D project selection process by combining multiple pieces of
evidence with different weights and reliabilities. As a result, the total
belief degrees and the overall performance can be generated for ranking and
selecting projects. Finally, a case study on the R&D project selection for the
National Science Foundation of China is conducted to show the effectiveness of
the proposed model. The data-driven evidential reasoning rule based model for
project evaluation and selection (1) utilizes experimental data to represent
experts' assessments by using belief distributions over the set of final
funding outcomes, and through this historic statistics it helps experts and
applicants to understand the funding probability to a given assessment grade,
(2) implies the mapping relationships between the evaluation grades and the
final funding outcomes by using historical data, and (3) provides a way to make
fair decisions by taking experts' reliabilities into account. In the
data-driven evidential reasoning rule based model, experts play different roles
in accordance with their reliabilities which are determined by their previous
review track records, and the selection process is made interpretable and
fairer. The newly proposed model reduces the time-consuming panel review work
for both managers and experts, and significantly improves the efficiency and
quality of project selection process. Although the model is demonstrated for
project selection in the NSFC, it can be generalized to other funding agencies
or industries.Comment: 20 pages, forthcoming in International Journal of Project Management
(2019
Bounds and Constructions of Singleton-Optimal Locally Repairable Codes with Small Localities
Constructions of optimal locally repairable codes (LRCs) achieving
Singleton-type bound have been exhaustively investigated in recent years. In
this paper, we consider new bounds and constructions of Singleton-optimal LRCs
with minmum distance , locality and minimum distance and
locality , respectively. Firstly, we establish equivalent connections
between the existence of these two families of LRCs and the existence of some
subsets of lines in the projective space with certain properties. Then, we
employ the line-point incidence matrix and Johnson bounds for constant weight
codes to derive new improved bounds on the code length, which are tighter than
known results. Finally, by using some techniques of finite field and finite
geometry, we give some new constructions of Singleton-optimal LRCs, which have
larger length than previous ones
The Key Successful Factors of Internet Business: The Study of Online Bookshop
Electronic commerce is viewed as a more and more important issue for the rapid growth of online commercial activities. The books, having the properties of numerous categories, low unit price, and the convenience of delivering, have become the major products on line. So the online bookshops are appropriate for study to find out the key successful factors of Internet business. We first conduct twice Delphi to confirm several factors that are important to success in Internet business and there are 32 factors to be chosen. We then calculate the relative weigh of each factor with the Analytic Hierarchy Process (AHP) and select 14 factors having the highest weight to be the key successful factors of Internet business. These 14 factors in order of weight include the ability of managing the business change, filling the Place with Entrepreneurs and growing with them, the ability of managing the customer relationship, targeting the right customers, the price can react to market quickly, building the knowledge management systems, excellent sever ice after payment, building distribution center to develop unbeatable logistics, the ability of managing the cost, offering Great Value, the ability of marketing by database, building the goodwill and brand image, getting the trust of virtual community and maintain it continually, and the ability of developing the technology
Coronary Computed Tomography Angiography—A Promising Imaging Modality in Diagnosing Coronary Artery Disease
BackgroundTraditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.MethodsCoronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 ±11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.ResultsAll CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.ConclusionThe 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments. [J Chin Med Assoc 2008;71(5):241–246
GIFD: A Generative Gradient Inversion Method with Feature Domain Optimization
Federated Learning (FL) has recently emerged as a promising distributed
machine learning framework to preserve clients' privacy, by allowing multiple
clients to upload the gradients calculated from their local data to a central
server. Recent studies find that the exchanged gradients also take the risk of
privacy leakage, e.g., an attacker can invert the shared gradients and recover
sensitive data against an FL system by leveraging pre-trained generative
adversarial networks (GAN) as prior knowledge. However, performing gradient
inversion attacks in the latent space of the GAN model limits their expression
ability and generalizability. To tackle these challenges, we propose
\textbf{G}radient \textbf{I}nversion over \textbf{F}eature \textbf{D}omains
(GIFD), which disassembles the GAN model and searches the feature domains of
the intermediate layers. Instead of optimizing only over the initial latent
code, we progressively change the optimized layer, from the initial latent
space to intermediate layers closer to the output images. In addition, we
design a regularizer to avoid unreal image generation by adding a small
ball constraint to the searching range. We also extend GIFD to the
out-of-distribution (OOD) setting, which weakens the assumption that the
training sets of GANs and FL tasks obey the same data distribution. Extensive
experiments demonstrate that our method can achieve pixel-level reconstruction
and is superior to the existing methods. Notably, GIFD also shows great
generalizability under different defense strategy settings and batch sizes.Comment: ICCV 202
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