Microgrid (MG) represents one of major drives of adopting Internet of Things for smart cities, as it effectively integrates various distributed energy resources. Indeed, MGs can be connected with each other and presented as a system of multimicrogrid (MMG). This paper proposes the optimal operation of MMGs by a cooperative energy and reserve scheduling model, in which energy and reserve can be cooperatively utilized among MMGs. In addition, values of Shapely are introduced to allocate economic benefits of the cooperative operation. Finally, a case study based on a system of MMGs is conducted, and simulation results verify the effectiveness of the proposed cooperative scheduling model.
A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as the subnet gateway, a two-user subnet and a single-fiber access link, which is realized by the Faraday-Michelson interferometer set-ups. The techniques of the quantum router, optical switch and trusted relay are assembled here to guarantee the feasibility and expandability of the quantum cryptography network. Five nodes of the network are located in the government departments and the secure keys generated by the quantum key distribution network are utilized to encrypt the instant video, sound, text messages and confidential files transmitting between these bureaus. The whole implementation including the hierarchical quantum cryptographic communication network links and the corresponding application software shows a big step toward the practical user-oriented network with a high security level. quantum cryptography, quantum key distribution, quantum cryptography networkIn the latest two decades, quantum cryptographic service has gradually been refined due to the rapid improvement of the quantum key distribution (QKD) technique in practice [1−5] . Derived from the fundamental laws of physics, it offers a highly secure communication between legal users, no matter how the eavesdropper tampers with the system in the open channel [6,7] . However, traditional point-to-point QKD protocols have their intrinsic limitations on the secure distance and expansibility of users. Quantum secret sharing with GHZ states or W states gives a scheme of the communication for more than two users [8−11] , nevertheless it is more meaningful in quantum communication instead of practical quantum cryptography. For the fast inflation of user number and unforeseen emergent demands of communication service, so far it seems that a robust quantum cryptography network compatible with the classical optical network is a potential solution.Since the first quantum cryptography idea for passive optical network (PON) was proposed by Townsend et al. [12,13] with beam splitters, many new topologies for quantum network have been designed and subsequently quantum network construction has been demonstrated in real-built telecom optical network. The first network experiment fielded by BBN with 3 nodes in Boston is based on the active optical switches [14] . Following that, we built a 4-port "star type" quantum network in Beijing benefited from a "quantum router" structure which can realize the passive routing with WDM apparatus [15] . SECOQC also constructs the network with 7 QKD links to connect 5 nodes in Vienna [16] . Recently, Chen et al. [17] applied the decoy state method to connect 3 nodes together by treating the node in the middle as a trusted relay.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.