Applied Mechanics and Materials Vols. 284-287

Abstract: UML is a rich semantic language, but it is difficult to ensure consistency of the diagrams you have written. In this paper, we propose cross checking rules to improve consistency among UML diagrams, especially between UML static and dynamic diagrams. We derive integrated metamodels in order to reflect more clear interactions of UML elements in the checking rules and use OCL(Object Constraint Language) to represent the checking rules accurately. By comparing with the well-formed rules of UML specification, we study on consistency of UML diagrams. We also derive integrated metamodels of static and dynamic diagrams by analyzing the relationships of UML diagrams. Finally, we test the usability of derived rules through a case study.

Abstract: Since Naor and Shamir introduced visual cryptography in 1994, numerous image sharing techniques have been proposed to protect the security of binary, gray, and color images. However, only few of them focus on grayscale image sharing. Because the size of the share images are usually very large, an image sharing method that can create share images with the same size as that of the secret image (expansion free) is more attractive. This study aims to propose a grayscale image sharing method to achieve the purposes of free expansion and meaningful image sharing simultaneously. Experimental results show that two meaningful share images can be effectively created by the proposed share image creation process. Moreover, the original grayscale secret image can be correctly decoded by the proposed secret image retrieval process.

Abstract: With the popularity and prevalence of mobile devices, they have become indispensable daily necessities. The rapid development of software and hardware technology has made mobile devices increasingly powerful in function. Mobile devices have been inextricably linked with people’s lives. Moreover, as a result of the prevalence of social networking sites, the topic of people’s social relationship mining has attracted the attention of numerous researchers. This paper presented a mobile device-assisted determining social relationship system, which mainly uses the mobile device to collect geographic information about the surrounding people to determine whether they are within the angle of view of the mobile device's camera. The information is stored in the pictures as the basis for people relationship mining. The proposed approach has automatic and rapid processing capabilities for large amounts of photo data.

Abstract: Information security is getting more important due to the highly-developed computer technologies. The information security is heavily dependent on cryptosystems such as RSA and elliptic curve cryptosystem (ECC). ECC is suitable for the resource-constrained devices such as embedded system or hand-held devices because ECC can achieve the same security level but uses less cost as compared to RSA. Galois/Finite field multiplication is the most crucial operation in ECC. There are three popular bases in finite field in GF(2m), polynomial basis (PB), normal basis (NB), and dual basis (DB). A low-complexity bit-parallel DB multiplier which employs multiplexer approach is presented in this paper. While comparing with other related works, the proposed DB multiplier saves at least 20% space complexity.

Abstract: Most applications of traditional full-text search, e.g., webpage search, are offline which exploit text search engine to preview the texts and set up related index. However, applications of online realtime full-text search, e.g., network Intrusion detection and prevention systems (IDPS) are too hard to implementation by using commodity hardware. They are expensive and inflexible for more and more occurrences of new virus patterns and the text cannot be previewed and the search must be complete realtime online. Additionally, IDPS needs multi-pattern matching, and then malicious packets can be removed immediately from normal ones without degrading the network performance. Considering the problem of realtime multi-pattern matching, we implement two sequential algorithms, Wu-Manber and Aho-Corasick, respectively over GPU parallel computation platform. Both pattern matching algorithms are quite suitable for the cases with a large amount of patterns. In addition, they are also easier extendable over GPU parallel computation platform to satisfy realtime requirement. Our experimental results show that the throughput of GPU implementation is about five to seven times faster than CPU. Therefore, pattern matching over GPU offers an attractive solution of IDPS to speed up malicious packets detection among the normal traffic by considering the lower cost, easy expansion and better performance.

Abstract: MIFARE is convenient contactless smart card, however a lot of studies recently indicated that, its encryption Crypto-1 can be broken. Even though the key authentication mechanism of MIFARE has been seriously affected, millions of MIFARE are still in use worldwide. Under the circumstances that, MIFARE card security vulnerability cannot be ignored while upgrading the MIFARE cards within a short period of time is impossible, it is practical to consider other ways to minimize the risk and possible damages.

Abstract: Purpose of this research wants to use a device, called Dante board, the board enabled AD converter. It digitalizes audio and transmits the audio using TCP/IP technology through cat5 cable to replace the expensive analog cable used in the past. Still, there are some problems needed to be overcome. First of all, during the analog-to-digital process, distorted audio issues are often encountered due to inconsistency of the encoder during digital sampling. In order to compensate the distortion during the conversion, frequency needs to be filtered out to compensate or attenuate. Secondly, due to delay in Internet transmission, the audio outputs by each device may not be synchronized. Therefore, each device needs to have its own clock to overcome the delay and reach the synchronized effect through clock synchronization. Also, the IEEE1588 precision time protocol (PTP) is used in clock synchronization to synchronize the audio in each device.

Abstract: Electronic cash (E-cash) is widely used due to the electronic commerce being in vogue. The date attached E-cash can apply for some services such as interest calculation, expired date processing, etc. In this paper, we propose two E-cash schemes with date attachable: the basic scheme with a better efficiency and the advanced scheme with an extensible date. The most remarkable contribution is that the advanced scheme can express any readable date with the relative year concept and still has a marvelous efficiency improvement as well as the basic scheme has.

Abstract: The problem of part-of-speech (POS) tagging or disambiguation is a practical issue in natural language processing (NLP) community, especially in the development of a machine translation system. The performance of POS tagging system may interference the subsequent analytical tasks in the translation process, and thereafter affects the overall translation quality. This paper presents a novel POS tagging system, iTagger, which is developed based on Selecting Base Classifiers on Bagging (SBCB) learning algorithm. In this work, the POS tagging task is regarded as a classification problem. Features such as the surrounding context of ambiguous candidates, n-gram information, lexical items and linguistic clues are used and automatically extracted from the annotated corpus. The proposed system has been compared against two state-of-the-art tagging methods, Hidden Markov Model (HMM) and Maximum Entropy. The empirical results conducted on the corpora of (English) Brown corpus, (Portuguese) Tycho Brahe corpus and the Chinese Tree Bank corpus reveal the competitiveness of iTagger. Moreover, the iTagger has been developed and released to the public as library and tool for various development and application purposes.

Abstract: Due to the trend that mobile devices are getting more and more popular, smart phone security becomes an important issue nowadays. This paper proposes an Android-based botnet, called JokerBot, to show the possible security problems in mobile devices. This paper describes JokerBot framework. JokerBot designs its own communication mechanism to allow different bots to communicate with each other. An attacker can use JokerBot to trigger many kinds of potential attacks, such as monitoring the SMS messages and location disclosure. Moreover, after a bot is created in a compromised smartphone, it is difficult to locate the botmaster and detect whether the smartphone is infected or not. Finally, this paper proposes some defense mechanisms to protect a smartphone against JokerBot attacks.