Determining node duty cycle using Q-learning and linear regression for WSN

Wireless sensor network(WSN)is effective for monitoring the target environment,which consists of a large number of sensor nodes of limited energy.An efficient medium access control(MAC)protocol is thus imperative to maximize the energy efficiency and performance of WSN.The most existing MAC protocols are based on the scheduling of sleep and active period of the nodes,and do not consider the relationship between the load condition and performance.In this paper a novel scheme is proposed to properly determine the duty cycle of the WSN nodes according to the load,which employs the Q-leaming technique and function approximation with linear regression.This allows low-latency energy-efficient scheduling for a wide range of traffic conditions,and effectively overcomes the limitation of Q-learning with the problem of continuous state-action space.NS3 simulation reveals that the proposed scheme significantly improves the throughput,latency,and energy efficiency compared to the existing fully active scheme and S-MAC.     

A performance evaluation of information security training in public sector

Recently, as the incidents of the security breach and the personal information leakage in public institutions and the major information/communication infrastructure have increased, the importance of the development and training of human resources specialized in cybersecurity, who can immediately respond to this are emphasized. Accordingly, the government has announced policies for the development of human resources, established and operated public sector cybersecurity training centers; however, there is no method for understanding the investment performance and effect of the present cybersecurity education/training in the public sector. For the establishment of a training system and the quality control of continuing education, a method for evaluating the performance of the training is needed, and this can prove the justification of the promotion of the training program and the sustainability of the training center. The goal of this study is to analyze the outcome of education and training in the field of information security and economic return on investment. For this purpose, through literature research on the outcome of the domestic and overseas education and training, this study drew a model that can apply.     

Security analysis of an unlinkable secret handshakes scheme

Recently, Huang and Cao proposed a novel and efficient unlinkable secret handshakes scheme with several security features including the affiliation-hiding property and the AKE-security. In this paper, we examine the security of the Huang-Cao scheme and show that the scheme fails to achieve two fundamental security requirements, the affiliation-hiding property and the AKE-security.     

Soft-switched,high frequency resonant AC-to-DC rectifier with high power factor

A high frequency and soft-switched AC-to-DC rectifier employing a series-type resonant circuit is proposed to overcome the disadvantages of the conventional peak-rectifying circuit. Using the proposed rectifier, a high power factor and low harmonic currents are obtained in the AC line. Furthermore, several advantages such as high power density and wide output voltage range can also be available. Through simulation and experimental results, the usefulness of the proposed rectifier is verified.     

Hard X-ray microscopy with Zernike phase contrast

Zernike phase contrast has been added to a full‐field X‐ray microscope with Fresnel zone plates that was in operation at 6.95 keV. The spatial resolution has also been improved by increasing the magnification of the microscope objective looking at the CsI(Tl) scintillation crystal. Cu no. 2000 meshes and a zone plate have been imaged to see the contrast as well as the spatial resolution. A Halo effect coming from the Zernike phase contrast was clearly visible on the images of meshes.     

Small signal modelling for the PWM series resonant converter

A discrete time domain modelling is presented for the pulse-width modulated series resonant converter (PWM-SRC) with a discontinuous current mode. This nonlinear system is linearized about its equilibrium state to obtain a linear discrete time model for the investigation of small signal performances such as the stability and transient response. The usefulness of this small signal model is verified by dynamic simulation.     

An efficient non-interactive deniable authentication scheme based on trapdoor commitment schemes

Deniable authentication scheme is one of useful tools for secure communications. The scheme allows a sender to prove the authenticity of a message to a specified receiver without permitting the receiver to prove that the message was authenticated by the sender. Non-interactive schemes are more attractive than interactive schemes in terms of communication overhead, and thus several non-interactive deniable authentication scheme have been proposed. In this paper, we propose an efficient non-interactive deniable authentication scheme based on trapdoor commitment scheme. We construct an efficient trapdoor commitment scheme which provides very efficient commitment evaluation operation. Then we design an efficient non-interactive deniable authentication scheme by using the trapdoor commitment scheme. We also prove the security of our scheme under firmly formalized security model.     

Proactive eviction of flow entry for SDN based on hidden Markov model

With the fast development of software defined network (SDN), numerous researches have been conducted for maximizing the performance of SDN. Currently, flow tables are utilized in OpenFlows witch for routing. Due to the space limitation of flow table and switch capacity, variousissues exist in dealing with the flows.The existing schemes typically employ reactive approach such that the selection of evicted entries occurs when timeout or table miss occurs. In this paper a proactive approach is proposed based on the prediction of the probability of matching of the entries. Here eviction occurs proactively when the utilization of flow table exceeds a threshold, and the flow entry of the lowestmatching probability is evicted. The matching probability is estimated using hiddenMarkov model (HMM).Computersimulation reveals that it significantly enhances the prediction accuracy and decreases the number of table misses compared to the standard Hard timeout scheme and Flow master scheme.