HyungWon Kim

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We study the time evolution of the entanglement entropy of a one-dimensional nonintegrable spin chain, starting from random nonentangled initial pure states. We use exact diagonalization of a nonintegrable quantum Ising chain with transverse and longitudinal fields to obtain the exact quantum dynamics. We show that the entanglement entropy increases(More)
  • HyungWon Kim
  • 2014 IEEE World Forum on Internet of Things (WF…
  • 2014
We propose a new method of multichannel allocation and routing for wireless mesh networks where each node generates event-driven video sensor data. Battery powered video camera sensors are often connected wirelessly to cover a large area. Such wireless video sensor networks are considered as major applications of Internet of Things (IoT). We analyze the(More)
We numerically construct slowly relaxing local operators in a nonintegrable spin-1/2 chain. Restricting the support of the operator to M consecutive spins along the chain, we exhaustively search for the operator that minimizes the Frobenius norm of the commutator with the Hamiltonian. We first show that the Frobenius norm bounds the time scale of relaxation(More)
With the introduction of IEEE 802.11ah wireless LAN standard, Internet of Things (IoT) is expected to develop more rapidly. IEEE 802.11ah introduces a relay node to extend wireless range with high energy efficiency for a large number of station nodes. This paper presents an efficient method of allocating multiple channels to multiple relay nodes of IEEE(More)
Battery durability is often the major constraint in low power wireless sensor networks. Hence in most low power scheduling methods, nodes switch between the active mode and sleep mode periodically. This paper proposes an energy efficient data transmission scheduling for each node in a multi-channel multi-hop, data aggregation network. The proposed method(More)