Efficient mining of frequent episodes from complex sequences

Discovering patterns with great significance is an important problem in data mining discipline. An episode is defined to be a partially ordered set of events for consecutive and fixed-time intervals in a sequence. Most of previous studies on episodes consider only frequent episodes in a sequence of events (called simple sequence). In real world, we may find a set of events at each time slot in terms of various intervals (hours, days, weeks, etc.). We refer to such sequences as complex sequences. Mining frequent episodes in complex sequences has more extensive applications than that in simple sequences. In this paper, we discuss the problem on mining frequent episodes in a complex sequence. We extend previous algorithm MINEPI to MINEPI+$\mathrm{MINEPI}+$ for episode mining from complex sequences. Furthermore, a memory-anchored algorithm called EMMA is introduced for the mining task. Experimental evaluation on both real-world and synthetic data sets shows that EMMA is more efficient than MINEPI+$\mathrm{MINEPI}+$.     

Cryptanalysis and improvement of nonrepudiable threshold multi-proxy multi-signature scheme with shared verification

Recently, Tzeng et al. proposed a nonrepudiable threshold multi-proxy multi-signature scheme with shared verification. In their scheme, a subset of original signers can delegate the signing power to a group of the designated proxy signers in such a way that: (i) A valid proxy signature can only be generated by a subset of these proxy signers for a group of the designated verifiers. (ii) The validity of the generated proxy signature can only be verified by a subset of the designated verifiers. This article, however, will demonstrate a security leak inherent in Tzeng et al.’s scheme that any verifier can check the validity of the proxy signature by himself with no help of other verifiers. That is, Tzeng et al.’s scheme cannot achieve their claimed security requirement. Finally, we will propose an improvement to eliminate the pointed out security leak.     

WMA: A Marking-Based Synchronized Multimedia Tutoring System for English Composition Studies

This paper presents a system, Web-based Multimedia Annotation (WMA) system, for english as foreign language learning in writing skills. The whole correcting process, including the instructor's voice and navigation events (i.e., tele-pointer (cursor), highlight, pen strokes, markings and annotations), can be captured through our system for later access. We address the issues of exploring involved media correlation to benefit adaptable presentation in a synchronization manner from temporal, spatial and content domains. The proposed computed synchronization techniques include speech-event binding process in the temporal domain, tele-pointer movement interpolation and adaptable handwriting presentation in the spatial domain, and visualized annotation erasing in the content domain. The experimental results show that in the speech-event binding process 74% of speech access entries for accessible visualized annotations are found. The acceptable rate of human perception of tele-pointer movement is higher than 85% if time interval is selected carefully. The accuracy of visualized annotation erasing for content removal is about 71%. Our user study shows that students can devote their efforts to writing practice because they can better understand their own mistakes corrected by the instructors using this multimedia presentation.     

SMCA: a general model for mining asynchronous periodic patterns in temporal databases

Mining periodic patterns in time series databases is an important data mining problem with many applications. Previous studies have considered synchronous periodic patterns where misaligned occurrences are not allowed. However, asynchronous periodic pattern mining has received less attention and only been discussed for a sequence of symbols where each time point contains one event. In this paper, we propose a more general model of asynchronous periodic patterns from a sequence of symbol sets where a time slot can contain multiple events. Three parameters min/spl I.bar/rep, max/spl I.bar/dis, and global/spl I.bar/rep are employed to specify the minimum number of repetitions required for a valid segment of nondisrupted pattern occurrences, the maximum allowed disturbance between two successive valid segments, and the total repetitions required for a valid sequence. A 4-phase algorithm is devised to discover periodic patterns from a time series database presented in vertical format. The experiments demonstrate good performance and scalability with large frequent patterns.     

A study on characteristics of interfacial transition zone in concrete

The aim of this study was to observe the behavior of the interfacial transition zone (ITZ) of high-performance concrete that was under curing in saturated lime water. From the Scanning Electron Microscope (SEM), it was found that the pores and hydration products at the ITZ, within 100 μm between the paste and aggregate, permuted each other during the early hydration stage, and then appeared as a large lump or strip. They gradually became irregular and small lumps for the further curing age. At the curing age of 56 days, the pores almost concentrated within an area of 0-15 μm from the aggregate edge. The hydration products were much denser with the increase in its distance from the aggregate edge.     

Two ID-based authenticated schemes with key agreement for mobile environments

With the rapid development of electronic commerce transactions on mobile devices, achieving secure communications between communication parties is an important issue. The typical solutions are authenticated key agreement protocols, designed to efficiently implement secure channels for two or more parties communicating via a public network by providing them with a shared secret key, called a session key. In this paper, we propose two key agreement schemes based on elliptic curve cryptosystems suited for mobile environments. The first one is an identity-based remote mutual authentication with key agreement scheme, and it is used to establish a session key between the client and the server. In the second one, we extend the proposed two-party authentication key exchange scheme to develop an efficient three-party authenticated key agreement scheme for establishing a session key between two users with the help of a trusted server. Both our proposed schemes achieve efficiency, practicability, simplicity, and strong notions of security.     

Convertible multi-authenticated encryption scheme

A convertible authenticated encryption (CAE) scheme allows the signer to generate a valid authenticated ciphertext on his chosen message such that only the designated recipient can retrieve the message. Further, the recipient has the ability to convert the authenticated ciphertext into ordinary signature in case of a dispute or repudiation. The previous proposed CAE schemes can only allow one signer to produce the authenticated ciphertext. It might be inadequate for multiparty environments. In this paper, we elaborate on the merits of CAE and multi-signature schemes to propose a convertible multi-authenticated encryption scheme which has the following advantages: (i) The size of the generated authenticated ciphertext is independent of the number of total participating signers. (ii) Except for the designated recipient, no one can obtain the signed message and verify its corresponding signature. (iii) The signature is cooperatively produced by a group of signers instead of a single signer. (iv) In case of a later dispute on repudiation, the recipient has the ability to convert the authenticated ciphertext into an ordinary one for convincing anyone of the signers’ dishonesty.     

A Novel RFID Tag Identification Protocol: Adaptive n-Resolution and k-Collision Arbitration

Since radio frequency identification (RFID) technology has become increasingly common in numerous applications, including large-scale supply chain management, improving the efficiency of RFID tag identification is an important task. In practical settings, the identification of RFID tags often occurs in a dynamic environment, in which tags move through a specific interrogation range. However, the literature contains few studies on the design of efficient identification protocols in dynamic environments. This study proposes a novel tag identification protocol that is particularly efficient in dynamic environments. the proposed protocol involves two anti-collision techniques: adaptive n-Resolution (AnR) and k-Collision Arbitration (kCA). These two techniques significantly improve the tag identification delay and communication overhead. This improvement is primarily due to the use of a newly designed challenge-response bit sequence mechanism and the information obtained from the previous tag identification procedure. As a result, AnR requires only a constant number of interrogation times regardless of the number of target tags, while kCA further improves the efficiency of tag identification with \(k\) -splitting collision arbitration. Rigorous analysis and simulation experiments show that this tag identification protocol significantly outperforms related methods (by at least 48.85 % identification delay and 23.87 % communication overhead can).     

A geographic map-based middleware framework to obfuscate smart vehicles’ locations

Multimedia Tools and Applications - In the 5G applications, smart vehicles typically use built-in positioning functions to query geographic map information or to access location-based multimedia or...     

Active circuits under wire bonding I/O pads in 0.13 μmeight-level Cu metal, FSG low-k inter-metal dielectric CMOS technology

Active circuits in terms of ring oscillator are moved to the place under the wire bonding pads in 0.13 μm full eight-level copper metal complementary metal-oxide-semiconductor process with fluorinated silicate glass low-k inter-metal dielectric. The bond pad with the 12 kÅ thick aluminum metal film as a bonding mechanical stress buffer layer is deposited on the topmost copper metal layer. No noticeable degradations in gate delay or cycle time of ring oscillator are detected in a variety of test structures subjected to bonding mechanical stress and thermal cycling stress. This indicates that the underlying process technology may be reliable and manufacturable in placing active circuits under the bonding pads and thereby the die area utility is recovered fully. More evidence is created from transmission line pulsing experiments as well as capacitive-coupling experiments