UWB-Based Localization in Wireless Sensor Networks

Localization has many important applications in wireless sensor networks, such as object searching and tracking, remote navigation, location based routing etc. The distance measurements have been based on a variety of technologies, such as acoustic, infrared, and UWB (ultra-wide band) media for localization pur-poses. In this paper, we propose UWB-based communication protocols for distance estimation and location calculation, namely a new UWB coding method, called U-BOTH (UWB based on Orthogonal Variable Spreading Factor and Time Hopping), an ALOHA-type channel access method and a message exchange protocol to collect location information. U-BOTH is based on IEEE 802.15.4a that was designed for WPANs (wireless personal area networks) using the UWB technology. We place our system in coal mine environ-ments, and derive the corresponding UWB path loss model in order to apply the maximum likelihood esti-mation (MLE) method to compute the distances to the reference sensors using the RSSI information, and to estimate the coordinate of the moving sensor using least squares (LS) method. The performance of the sys-tem is validated using theoretic analysis and simulations. Results show that U-BOTH transmission technique can effectively reduce the bit error rate under the path loss model, and the corresponding ranging and local-ization algorithms can accurately compute moving object locations in coal mine environments.

Security-aware Signal Packing Algorithm for CAN-based Automotive Cyber-physical Systems

Network and software integration pose severe challenges in cyber-security for controller area network (CAN)-based automotive cyber-physical system (ACPS), therefore we employ message authentication code (MAC) to defend CAN against masquerade attack, but the consequent bandwidth overhead makes it a necessity to find the tradeoff among security, real-time and bandwidth utilization for signal packing problem (SPP) of CAN. A mixed-security signal model is firstly proposed to formally describe the properties and requirements on security and real-time for signals, and then a mixed-integer linear programming (MILP) formulation of SPP security-aware signal packing (SASP) is implemented to solve the tradeoff problem, where the bandwidth utilization is improved and the requirements in both security and real-time are met. Experiments based on both society of automotive engineers (SAE) standard signal set and simulated signal set showed the effectiveness of SASP by comparing with the state-of-the-art algorithm. © 2014 Chinese Association of Automation.

An Immunity-Based IOT Environment Security Situation Awareness Model

To effectively perceive network security situation under IOT environment, an Immunity-based IOT Environment Security Situation Awareness (IIESSA) model is proposed. In IIESSA, some formal definitions for self, non-self, antigen and detector are given. According to the relationship between the antibody-concentration of memory detectors and the intensity of network attack activities, the security situation evaluation method under IOT environment based on artificial immune system is presented. And then according to the situation time series obtained by the mentioned evaluation method, the security situation prediction method based on grey prediction theory is presented for forecasting the intensity and security situation of network attack activities that the IOT environment will be suffered in next step. The experimental results show that IIESSA provides a novel and effective model for perceiving security situation of IOT environment.

Unsupervised Anomaly Detection for Network Flow Using Immune Network Based K-means Clustering

To detect effectively unknown anomalous attack behaviors of network traffic,an Unsupervised Anomaly Detection approach for network flow using Immune Network based K-means clustering(UADINK)is proposed.In UADINK,artificial immune network based K-means clustering algorithm(aiNet_KMC)is introduced to cluster network flow,i.e.extracting abstract internal images from network flows and obtaining an optimizing parameter K of K-means by aiNet model,and network flows are clustered by K-means algorithm.The cluster labeling algorithm(clusLA)and the network flow anomaly detection algorithm(NFAD)are introduced to detect anomalous attack behaviors of network flows,where the clusLA algorithm is used for labeling whether each cluster belongs to malicious,and the labeled clusters are regarded as detectors to identify anomaly network flows by NFAD.To evaluate the effectiveness of UADINK,the ISCX 2012 IDS dataset is considered as the simulating experimental dataset.Compared with the NDM based K-means anomaly detection approach,the results show that UADINK is a radical anomaly detection approach in order to detect anomalies of network flows.

FPGA based unified architecture for public key and private key cryptosystems

Recently, security in embedded system arises attentions because of modern electronic devices need cau- tiously either exchange or communicate with the sensitive data. Although security is classical research topic in world- wide communication, the researchers still face the problems of how to deal with these resource constraint devices and en- hance the features of assurance and certification. Therefore, some computations of cryptographic algorithms are built on hardware platforms, such as field program gate arrays （FPGAs）. The commonly used cryptographic algorithms for digital signature algorithm （DSA） are rivest-shamir-adleman （RSA） and elliptic curve cryptosystems （ECC） which based on the presumed difficulty of factoring large integers and the algebraic structure of elliptic curves over finite fields. Usu- ally, RSA is computed over GF（p）, and ECC is computed over GF（p） or GF（2P）. Moreover, embedded applications need advance encryption standard （AES） algorithms to pro- cess encryption and decryption procedures. In order to reuse the hardware resources and meet the trade-off between area and performance, we proposed a new triple functional arith- metic unit for computing high radix RSA and ECC operations over GF（p） and GF（2P）, which also can be extended to support AES operations. A new high radix signed digital （SD） adder has been proposed to eliminate the carry propagations over GF（p）. The proposed unified design took up 28.7% less hardware resources than implementing RSA, ECC, and AES individually, and the experimental results show that our proposed architecture can achieve 141.8 MHz using approxi- mately 5.5k CLBs on Virtex-5 FPGA.