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Effective operation and performance improvement methods for OMTP BONDI-based mobile Web widget resources
Jiwoong Bang, Daewon Kim
Front. Inform. Technol. Electron. Eng., 2011, 12(10): 787-799.
https://doi.org/10.1631/jzus.C1000379
The Open Mobile Terminal Platform (OMTP) is a global forum made by telecommunications providers to promote user-oriented mobile services and data businesses. Devised by OMTP, BONDI is a browser-based application or a mobile Web run-time platform to help widgets make good use of the functions of mobile devices in a secure way. BONDI enables applications programmed with Web standard technologies such as HTML, JavaScript, CSS, and AJAX to reach the internal functions of mobile devices. Since BONDI, which is not just a simple network application, can reach the internal resources of devices in standard ways, it enables the application and widgets to be developed regardless of the operating system (OS) or platform. Web browser-based widgets are vulnerable to the network environment, and their execution speed can be slowed as the operations of the widgets or applications become heavy. Compared with the native widgets inside the device, however, those Web widgets will be continuously used thanks to the user-friendly simple interface and the faster speed in using Web resources. This study deals with a method to effectively operate and manage the resources of OMTP BONDI Web widget and provides improved results based on running performance evaluation experiments. The experiments were carried out to improve the entire operating time by enhancing the module-loading speed. In this regard, only indispensable modules were allowed to be loaded while the BONDI widget was underway. For this purpose, the widget resource list, which can make the operating speed of the BONDI widget faster, was redefined while a widget cache was employed. In addition, the widget box, a management tool for removed widgets, was devised to store temporarily idle widgets.
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k-Dimensional hashing scheme for hard disk integrity verification in computer forensics
Zoe Lin Jiang, Jun-bin Fang, Lucas Chi Kwong Hui, Siu Ming Yiu, Kam Pui Chow, Meng-meng Sheng
Front. Inform. Technol. Electron. Eng., 2011, 12(10): 809-818.
https://doi.org/10.1631/jzus.C1000425
Verifying the integrity of a hard disk is an important concern in computer forensics, as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation. A typical approach is to compute a single chained hash value of all sectors in a specific order. However, this technique loses the integrity of all other sectors even if only one of the sectors becomes a bad sector occasionally or is modified intentionally. In this paper we propose a k-dimensional hashing scheme, kD for short, to distribute sectors into a kD space, and to calculate multiple hash values for sectors in k dimensions as integrity evidence. Since the integrity of the sectors can be verified depending on any hash value calculated using the sectors, the probability to verify the integrity of unchanged sectors can be high even with bad/modified sectors in the hard disk. We show how to efficiently implement this kD hashing scheme such that the storage of hash values can be reduced while increasing the chance of an unaffected sector to be verified successfully. Experimental results of a 3D scheme show that both the time for computing the hash values and the storage for the hash values are reasonable.
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An algorithm that minimizes audio fingerprints using the difference of Gaussians
Myoungbeom Chung, Ilju Ko
Front. Inform. Technol. Electron. Eng., 2011, 12(10): 836-845.
https://doi.org/10.1631/jzus.C1000396
Recently, many audio search sites headed by Google have used audio fingerprinting technology to search for the same audio and protect the music copyright using one part of the audio data. However, if there are fingerprints per audio file, then the amount of query data for the audio search increases. In this paper, we propose a novel method that can reduce the number of fingerprints while providing a level of performance similar to that of existing methods. The proposed method uses the difference of Gaussians which is often used in feature extraction during image signal processing. In the experiment, we use the proposed method and dynamic time warping and undertake an experimental search for the same audio with a success rate of 90%. The proposed method, therefore, can be used for an effective audio search.
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A construction of inter-group complementary codes with flexible ZCZ length
Li-fang Feng, Xian-wei Zhou, Ping-zhi Fan
Front. Inform. Technol. Electron. Eng., 2011, 12(10): 846-854.
https://doi.org/10.1631/jzus.C1000360
A general construction of inter-group complementary (IGC) codes is proposed based on perfect complementary (PC) codes, interleaving operation, and the orthogonal matrix. The correlation properties of the newly constructed IGC codes can be described as follows: (1) the autocorrelation sidelobes of the codes are zeros in the zero correlation zone (ZCZ); (2) the cross-correlation functions (CCFs) between any two different codes of the same group are zeros in the ZCZ; (3) the CCFs between any two codes of different groups are zeros everywhere. The key point of this construction is that the ZCZ length of the generated IGC codes can be chosen flexibly. It is well known that there is a limitation between the ZCZ length and the number of mates; that is, the smaller is the length of ZCZ, the more are the IGC codes that can be generated. Therefore, if we can choose the ZCZ length of the IGC codes flexibly according to the requirement of the system, more users can be accommodated in the system.
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Serial decoding of rateless code over noisy channels
Ke-di Wu, Zhao-yang Zhang, Shao-lei Chen, Sheng-tian Yang, Pei-liang Qiu
Front. Inform. Technol. Electron. Eng., 2011, 12(10): 855-866.
https://doi.org/10.1631/jzus.C1000340
Rateless code usually generates a potentially infinite number of coded packets at the encoder and collects enough packets at the decoder to ensure reliable recovery of multiple information packets. The conventional rateless decoder usually works in a parallel manner which needs to initiate a new belief propagation (BP) decoding procedure upon each newly received collection of coded packets, thereby resulting in prohibitive decoding complexity in practice. In this paper, we present a novel serial decoding algorithm, i.e., the serial storage belief propagation (SS BP) algorithm, for rateless codes over noisy channels. Specifically, upon receiving a new group of coded packets, the decoder initiates a new attempt to decode all the packets received so far, using the results of the previous attempt as initial input. Moreover, in each iteration of the new attempt, the decoder serially propagates the messages group by group from the most recent one to the earliest one. In this way, the newly updated messages can be propagated faster, expediting the recovery of information packets. In addition, the proposed serial decoding algorithm has significantly lower complexity than the existing parallel decoding algorithms. Simulation results validate its effectiveness in AWGN, Rayleigh, and Rician fading channels.
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8 articles
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