20,822 research outputs found
Analyzing the Key Drivers of Contractors’ Temporary Competitive Advantage in the Competition of International High-speed Rail Projects
This is a pre-print of an article published in KSCE Journal of Civil Engineering. The final authenticated version is available online at: https://doi.org/10.1007/s12205-019-0602-4
After temporary competitive advantage (TCA) being proposed, this concept has received a lot of attention from academia and industry. For international HSR contractors, how to form their TCA and win out over the competition for new projects is crucial, while only a few studies focus on this issue. This research aims to develop a TCA system that reflects the characteristics of high-speed rail (HSR) contractors in the corporation and project levels. At first, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) was conducted to explore and examine the key drivers and their relationships with contractors’ TCA
High-capacity quantum secure direct communication based on quantum hyperdense coding with hyperentanglement
We present a quantum hyperdense coding protocol with hyperentanglement in
polarization and spatial-mode degrees of freedom of photons first and then give
the details for a quantum secure direct communication (QSDC) protocol based on
this quantum hyperdense coding protocol. This QSDC protocol has the advantage
of having a higher capacity than the quantum communication protocols with a
qubit system. Compared with the QSDC protocol based on superdense coding with
-dimensional systems, this QSDC protocol is more feasible as the preparation
of a high-dimension quantum system is more difficult than that of a two-level
quantum system at present.Comment: 5 pages, 2 figur
The Least-core and Nucleolus of Path Cooperative Games
Cooperative games provide an appropriate framework for fair and stable profit
distribution in multiagent systems. In this paper, we study the algorithmic
issues on path cooperative games that arise from the situations where some
commodity flows through a network. In these games, a coalition of edges or
vertices is successful if it enables a path from the source to the sink in the
network, and lose otherwise. Based on dual theory of linear programming and the
relationship with flow games, we provide the characterizations on the CS-core,
least-core and nucleolus of path cooperative games. Furthermore, we show that
the least-core and nucleolus are polynomially solvable for path cooperative
games defined on both directed and undirected network
Improving the security of secure direct communication based on secret transmitting order of particles
We analyzed the security of the secure direct communication protocol based on
secret transmitting order of particles recently proposed by Zhu, Xia, Fan, and
Zhang [Phys. Rev. A 73, 022338 (2006)], and found that this scheme is insecure
if an eavesdropper, say Eve, wants to steal the secret message with Trojan
horse attack strategies. The vital loophole in this scheme is that the two
authorized users check the security of their quantum channel only once. Eve can
insert another spy photon, an invisible photon or a delay one in each photon
which the sender Alice sends to the receiver Bob, and capture the spy photon
when it returns from Bob to Alice. After the authorized users check the
security, Eve can obtain the secret message according to the information about
the transmitting order published by Bob. Finally, we present a possible
improvement of this protocol.Comment: 4 pages, no figur
Totally balanced combinatorial optimization games
Combinatorial optimization games deal with cooperative games for which the value of every subset of players is obtained by solving a combinatorial optimization problem on the resources collectively owned by this subset. A solution of the game is in the core if no subset of players is able to gain advantage by breaking away from this collective decision of all players. The game is totally balanced if and only if the core is non-empty for every induced subgame of it. We study the total balancedness of several combinatorial optimization games in this paper. For a class of the partition game [5], we have a complete characterization for the total balancedness. For the packing and covering games [3], we completely clarify the relationship between the related primal/dual linear programs for the corresponding games to be totally balanced. Our work opens up the question of fully characterizing the combinatorial structures of totally balanced packing and covering games, for which we present some interesting examples: the totally balanced matching, vertex cover, and minimum coloring games.link_to_subscribed_fulltex
Aberrant posterior cingulate connectivity classify first-episode schizophrenia from controls: A machine learning study
Background Posterior cingulate cortex (PCC) is a key aspect of the default mode network (DMN). Aberrant PCC functional connectivity (FC) is implicated in schizophrenia, but the potential for PCC related changes as biological classifier of schizophrenia has not yet been evaluated. Methods We conducted a data-driven approach using resting-state functional MRI data to explore differences in PCC-based region- and voxel-wise FC patterns, to distinguish between patients with first-episode schizophrenia (FES) and demographically matched healthy controls (HC). Discriminative PCC FCs were selected via false discovery rate estimation. A gradient boosting classifier was trained and validated based on 100 FES vs. 93 HC. Subsequently, classification models were tested in an independent dataset of 87 FES patients and 80 HC using resting-state data acquired on a different MRI scanner. Results Patients with FES had reduced connectivity between PCC and frontal areas, left parahippocampal regions, left anterior cingulate cortex, and right inferior parietal lobule, but hyperconnectivity with left lateral temporal regions. Predictive voxel-wise clusters were similar to region-wise selected brain areas functionally connected with PCC in relation to discriminating FES from HC subject categories. Region-wise analysis of FCs yielded a relatively high predictive level for schizophrenia, with an average accuracy of 72.28% in the independent samples, while selected voxel-wise connectivity yielded an accuracy of 68.72%. Conclusion FES exhibited a pattern of both increased and decreased PCC-based connectivity, but was related to predominant hypoconnectivity between PCC and brain areas associated with DMN, that may be a useful differential feature revealing underpinnings of neuropathophysiology for schizophrenia
Pentaquark Magnetic Moments In Different Models
We calculate the magnetic moments of the pentaquark states from different
models and compare our results with predictions of other groups.Comment: 17 pages, no figur
Quantum secure direct communication network with superdense coding and decoy photons
A quantum secure direct communication network scheme is proposed with quantum
superdense coding and decoy photons. The servers on a passive optical network
prepare and measure the quantum signal, i.e., a sequence of the -dimensional
Bell states. After confirming the security of the photons received from the
receiver, the sender codes his secret message on them directly. For preventing
a dishonest server from eavesdropping, some decoy photons prepared by measuring
one photon in the Bell states are used to replace some original photons. One of
the users on the network can communicate any other one. This scheme has the
advantage of high capacity, and it is more convenient than others as only a
sequence of photons is transmitted in quantum line.Comment: 6 pages, 2 figur
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