Search

The accuracy of attitude and heading measurement, as well as the system real-time performance are basic indicators used to evaluate an attitude and heading reference system (AHRS). In order to improve the attitude and heading measurement accuracy under dynamic complex environment, the AHRS system should also have numerical stability and calculation robustness. The AHRS system based on MEMS multi-sensor fusion can realize fusion processing of data measured by multiple sensors, so as to calculate and obtain the optimal carrier attitude and heading information, conduct real-time output, and improve the accuracy and reliability of attitude and heading measurement. For the AHRS system consisting of MEMS gyroscope, accelerometer and triaxial magnetometer, attitude and heading detection principle and algorithm based on MEMS multi-sensor fusion were proposed in this study: The information of the system itself was firstly used to discriminate motion state of the carrier within the filtering cycle, and then Kalman filtering was conducted using different measured information according to motion state to correct the attitude error angle caused by gyroscopic drift. On this basis, an attitude fusion algorithm based on extended Kalman filtering technology was designed for time update process of Kalman filtering, output information of accelerometer was taken as observed quantity under certain conditions to realize measurement updating process of Kalman filtering, and then attitude angle was calculated. In an optical fiber attitude and heading system project in practical engineering, a vehicle field test analysis was carried out simultaneously with the system using ordinary attitude algorithm, and the results showed that the extended Kalman filtering algorithm designed according to the simulation results could realize multi-sensor information fusion, improve measurement accuracy and realize accurate attitude positioning, so as to provide simpler and more flexible criteria for carrier motion status. The results have verified the accuracy and reliability of the algorithm, so it is feasible in practical engineering.

System dynamics (SD) have been used in water resources management for many years. However, water resources management using SD is usually in one direction, up to down or down to up, and does not consider internal and external system feedbacks, which may mislead managers and reduce the adaptability of water resources systems. Therefore, dynamic management of a water resources-socioeconomic-environmental (WSE) system based on feedbacks was established in this paper using SD, and a feedback function considering different intensities of feedbacks was proposed. The Beijing-Tianjin-Hebei region (BTHR), China, was chosen as the study area. Three subsystems were included in the WSE system: a socioeconomic subsystem, a water resources subsystem, and an environmental subsystem. We established and compared different dynamic management scenarios with various intensities of feedbacks. The results show that the shortage of water resources and pollution in the BTHR will continue to deteriorate from 2015 to 2030 if no management measures are taken, and the government should direct more attention to reducing the water demand of primary industry and population growth. In addition, we found that the three subsystems in the WSE system influence each other and evolve mutually. In particular, the influence of the water resources subsystem on the environmental subsystem is remarkable and cannot be ignored. This paper may act as a guide for adaptive and multi-objective management of WSE systems.

Recently, Kumari et al., pointed out that Chang et al.’s scheme “Untraceable dynamic-identity-based remote user authentication scheme with verifiable password update” has several drawbacks and does not provide any session key agreement. Hence, they proposed an improved remote user authentication scheme with key agreement based on Chang et al.’s protocol. They claimed that the improved method is secure. However, we found that their improvement still has both anonymity breach and smart card loss password guessing attack which cannot be violated in the ten basic requirements advocated for a secure identity authentication using smart card by Liao et al. Thus, we modify their protocol to encompass these security functionalities which are needed in a user authentication system using smart card.

The conditions under which multiplication verification (3 × 6 = 12, true or false?) involves product retrieval and comparison or familiarity-based recognition judgements has not been clearly established. In two experiments examining verification of single-digit multiplication problems, we used Retrieval-Induced Forgetting (RIF), a signature of retrieval use, as an index of product retrieval in multiplication verification. In Experiment 1, 72 adults practiced multiplication either in a production format or in a verification format and then were tested on corresponding addition and control problems. The results showed RIF (i.e., slower answer production for addition problems whose multiplication counterparts had been practiced) in both the production-practice and the verification-practice groups, but RIF was stronger following true than false verification. Experiment 2 tested verification with related-false and unrelated-false products. Related-false equations produced longer RTs than unrelated false equations. Practice of true, related-false and unrelated-false multiplication equations all produced RIF of the addition counterparts but, overall, related-false multiplication equations produced relatively weak RIF. The results indicated that product retrieval mediates multiplication verification even when false answers are weak associative lures and suggest that a retrieve-and-compare process is the default strategy when false answers are at least plausible. We conclude that the presented answer in verification equations act as retrieval-priming stimuli with true equations priming correct answer retrieval and related-false answers interfering with correct answer retrieval.

using sliding mode control and genetic algorithms, in this paper, a new optimal active control strategy is presented for truss bridge structure installed with giant magnetostrictive material actuators (GMMAs). The precise location information of GMMAs is determined using genetic algorithm, an active sliding control law is proposed based on the Lyapunov function method, and the real control force is provided by the GMMA via input current. A 32m span steel truss bridge structure subjected to El Centro earthquake record is provided to testify the effectiveness of the proposed control strategy. Simulation results show that (a) the GMMA is an effective vibration absorber and (b) the optimal active control strategy presented in the paper is feasible and effective for the reduction of vibration response quantities of the truss bridge structure subjected to ground motion.

Radio frequency identification tag authentication protocols are generally classified as non-full-fledged and full-fledged, according to the resource usage of the tags. The non-full-fledged protocols typically suffer de-synchronization, impersonation and tracking attacks, and usually lack scalability. The full-fledged protocols, supporting cryptographic functions, are designed to overcome these weaknesses. This paper examines several elliptic-curve-cryptography (ECC)-based full-fledged protocols. We found that some still have security and privacy issues, and others generate excessive communication costs between the tag and the back-end server. Motivated by these observations, we construct two novel protocols, PI and PII. PI is designed for secure environments and is suitable for applications, including E-Passport and toll payment in vehicular ad-hoc networks. PII is for hostile environments and can be applied in pseudonymous payment and anti-counterfeiting services. After analysis, we conclude that PII can resist many attacks, outperform previous ECC-based proposals in communication efficiency, and provide mutual authentication function and scalability.

The electricity transmission-distribution is an important link of power system. Pricing transmission-distribution is the key part in the new round electricity market reform in China. The paper investigates the components of cost during transmission and distribution considering the different levels of voltage under government regulation, which forms original pricing model according to the reasonable profit pricing mode. Based on the above model, we apply System Dynamics to simulate the trend of the transmission-distribution price and capacity under the different scenarios classified by return on investment. The result of the simulation shows that the increasing ROI can raise the grid capacity investment, but it can’t motivate power grid companies to reduce costs and improve management efficiency.

Untraceable electronic cash is an attractive payment tool for electronic-commerce because its anonymity property can ensure the privacy of payers. However, this anonymity property is easily abused by criminals. In this paper, several recent untraceable e-cash systems are examined. Most of these provide identity revealing only when the e-cash is double spent. Only two of these systems can disclose the identity whenever there is a need, and only these two systems can prevent crime. We propose a novel e-cash system based on identity-based bilinear pairing to create an anonymity revocation function. We construct an identity-based blind signature scheme, in which a bank can blindly sign on a message containing a trustee-approved token that includes the user's identity. On demand, the trustee can disclose the identity for e-cash using only one symmetric operation. Our scheme is the first attempt to incorporate mutual authentication and key agreement into e-cash protocols. This allows the proposed system to attain improvement in communication efficiency when compared to previous works.

In a multi-server environment, a user only needs to register at the registration center once instead of repeatedly registering in each server. After registration, the user can access the resources of any of the servers in the system. Many protocols have been proposed for the same. Recently, Geng–Zhang, Zhu et al., and Yoon–Yoo each proposed a multi-server authentication scheme. They claimed that their schemes are secure and can withstand various attacks. However, after analyses, we found that their schemes are deficient. In this paper, we first demonstrate the deficiencies of these three protocols in turn and then show our improvement on Geng–Zhang's protocol. Our improvement makes use of both the user's and the server's secrecy to achieve mutual authentication. This results in a two-pass multi-server authentication scheme. We have analyzed its security with respect to several factors such as mutual authentication, perfect forward and backward secrecy, and prevention of smart-card-lost attack. Moreover, almost all of the parameters required for a user to log on to a server can be pre-computed. This is very important for a low-energy mobile computing device. That is, our improvement is not only one of the most efficient and secure schemes in this area but also suitable for mobile device. Copyright © 2011 John Wiley & Sons, Ltd.

Near-term digital radio (NTDR) network is a kind of MANET in which mobile nodes are assigned into different clusters. Therefore, it can let the nodes to communicate with each other efficiently in a large area. Despite several NTDR protocols have been proposed, there still lacks an efficient secure one. Accordingly, in this paper, we propose a new method based on ID-based bilinear pairings to overcome the unsolved security problems nowadays. After our analysis, we conclude that our scheme is the first protocol for NTDR network that is not only secure but also very efficient.

In 2004, Ari Juels proposed a Yoking-Proofs protocol for RFID systems. Their aim is to permit a pair of tags to generate a proof which is verifiable off-line by a trusted entity even when the readers are potentially untrusted. However, we found that their protocol does not possess the anonymity property but also suffers from both known-plaintext attack and replay attack. Wong et al. [Kirk H.M. Wong, Patrick C.L. Hui, Allan C.K. Chan, Cryptography and authentication on RFID passive tags for apparel products, Computer in Industry 57 (2005) 342-349] proposed an authentication scheme for RFID passive tags, attempting to be a standard for apparel products. Yet, to our review, their protocol suffers from guessing parameter attack and replay attack. Moreover, both of the schemes have the common weakness: the backend server must use brute search for each tag's authentication. In this paper, we first describe the weaknesses in the two above-mentioned protocols. Then, we propose a novel efficient scheme which not only achieve the mutual authentication between the server and the tag but also can satisfy all the security requirements needed in an RFID system.

A virtual enterprise (VE) is an organization intended to cope with the rapidly changing manufacturing environment. Organization building is important in virtual domains because it has largely been affecting the success of VEs. However, the process of forming a VE is based on self-determination by the participants. This paper adopts a bargaining model under a scenario of incomplete information to formalize the formation process, considers the characteristics of the VE formation process, presents the pricing strategies for the corresponding bargaining, and verifies the correctness and validity of the pricing strategies using computer simulation. This paper breaks through the relative research that compares the formation process with partner selection from the core enterprise’s perspective and also provides the basis for the intelligent information platform of VE, whose key part is pricing software.

In order to solve the problem of accurately detecting the weak acoustic signal for remote underwater target, a novel hybrid intelligent target-detection method for underwater acoustic signals based on empirical mode decomposition (EMD), feature distance evaluation technique (FDET) and fuzzy support vector data description (FSVDD) is proposed. The method consists of three stages. Firstly, some signal processing methods, like filtration, Hilbert envelope-demodulation and EMD are carried out to extract the time- and frequency-domain statistical features from original underwater acoustic signals, and these features make up an integrated feature set. Secondly, with the FDET, the salient feature set is obtained from the integrated feature set. Finally, the salient features are input into the detector based on FSVDD to detect the underwater targets intelligently. This method is applied to target detection of underwater vehicle. Testing results show that the proposed method has better detection performance than the traditional detector based on SVDD, with a high detection success rate.

We provide a brief rebuttal of Chang (2012), who suggested that there were flaws in our article, Chen et al. (2011), that deserved further investigation and comment. We believe that these criticisms are unfounded, and offer some additional details related to the intractable discrete elliptic curve discrete logarithm problem to further support the case we wish to make.