The tapered slot antenna, such as Vivaldi, has been widely used due to its ultra-wideband, high gain, simple feed structure, and easy fabrication. However, there is no rigorous analytical theory for this type of antenna. This paper analyzed the metal parts of a tapered slot antenna in a conical coordinate system with the medium analyzed in rectangular coordinates. This mixed mode gave an approximate analytical form for the tapered slot antenna with the field distribution and radiation characteri...

This paper presents an effective keyword search method for data-centric extensive markup language (XML) documents. The method divides an XML document into compact connected integral subtrees, called self-integral trees (SI-Trees), to capture the structural information in the XML document. The SI-Trees are generated based on a schema guide. Meaningful self-integral trees (MSI-Trees) are identified, which contain all or some of the input keywords for the keyword search in the XML documents. Indexi...

Today's firewalls and security gateways are required to not only block unauthorized accesses by authenticating packet headers, but also inspect flow payloads against malicious intrusions. Deep inspection emerges as a seamless integration of packet classification for access control and pattern matching for intrusion prevention. The two function blocks are linked together via well-designed session lookup schemes. This paper presents an architecture-aware session lookup scheme for deep inspection o...

Dramatically increasing amounts of digital data are placing huge requirements on storage systems. IP-networked storage systems, such as the network file system (NFS)-based network-attached storage (NAS) systems and the iSCSI-storage area network (SAN) systems, have become increasingly common in today's local area network (LAN) environments. The emergence of new storage techniques, such as object-based storage (OBS) and content aware storage (CAS), significantly improves the functionality of stor...

Content addressable storage (CAS) is a promising technology for improving storage efficiency as well as access throughput. Currently, many CAS products are implemented on the block level, which results in loss of file information. Thus, some sophisticated optimizations cannot be achieved, such as accurate file-prefetching. This paper presents a file-aware block-level storage system combined with the CAS function. In contrast with some existing file-level CAS, this system is transparent to upper-...

The reliability of silicon-oxide-nitride-oxide-silicon (SONOS) type memories was analyzed using the charge pumping method and I-V tests at different temperatures to study its endurance and retention characteristics. A simple model was used to explain the charge loss phenomenon, with a dual-erasure method developed to improve the endurance and retention characteristics. The results indicate that the coexistence of injected holes and electrons after long term cycling, referred to as the mismatch p...

A high capacity data hiding technique was developed for compressed digital audio. As perceptual audio coding has become the accepted technology for storage and transmission of audio signals, compressed audio information hiding enables robust, imperceptible transmission of data within audio signals, thus allowing valuable information to be attached to the content, such as the song title, lyrics, composer's name, and artist or property rights related data. This paper describes simultaneous low bit...

High quality strain-relaxed thin SiGe virtual substrates have been achieved by combining the misfit strain technique and the point defect technique. The point defects were first injected into the coherently strained SiGe layer through the “inserted Si layer” by argon ion implantation. After thermal annealing, an intermediate SiGe layer was grown with a strained Si cap layer. The inserted Si layer in the SiGe film serves as the source of the misfit strain and prevents the threading di...

As mask features scale to smaller dimensions, the so-called “3-D mask effects” which have mostly been neglected before, become important. This paper properly models the 3-D thick mask effects, and then analyses the object-based inverse lithography technique using a simulated annealing algorithm to determine the mask shapes that produce the desired on-wafer results. Evaluations against rigorous simulations show that the synthesized masks provide good image fidelity up to 0.94, and thi...

The construction of Büchi automata from linear temporal logic is a significant step in model checking. This paper presents a depth-first construction algorithm to obtain simple Büchi automata from linear-time temporal logic which significantly reduces the sizes of the state spaces. A form-filling algorithm was used to reduce the size of the generated automata and the algorithms were applied directly to state-based Büchi automata, without transformation into transition-based automa...

In networks, the stable path problem (SPP) usually results in oscillations in interdomain systems and may cause systems to become unstable. With the rapid development of internet technology, the occurrence of SPPs in interdomain systems has quite recently become a significant focus of research. A framework for checking SPPs is presented in this paper with verification of an interdomain routing system using formal methods and the NuSMV software. Sufficient conditions and necessary conditions for ...

An abstraction method developed for the explicit linear temporal logic model checking was geared towards reducing the useless part of the state space during the abstraction period. This reduces the cost during the abstraction period relative to models requiring many useless states. A dining-philosophers example comparing this abstraction method with conventional methods indicates that a large proportion of the state space has been reduced by this abstraction method. Finally, the abstract method ...

Dynamic airspace management (DAM) is an important approach to extend limited air space resources by using them more efficiently and flexibly. This paper analyzes the use of the dynamic air-route adjustment (DARA) method as a core procedure in DAM systems. DARA method makes dynamic decisions on when and how to adjust the current air-route network with the minimum cost. This model differs from the air traffic flow management (ATFM) problem because it considers dynamic opening and closing of air-ro...

Nonvolatile memories (NVMs) with triple layers of silicon nanocrystals were fabricated with conventional CMOS technology. This paper explores the program/erase performance and reliability of NVMs with three layers of nanocrystals. The results indicate that the nanocrystals in the triple-layer nanocrystal NVM (NCNVM) are difficult to fully charge during the programming process. The programming speed of the triple-layer NCNVMs is quicker than that of single-layer NCNVMs, which means that the secon...

In multipath environments, the error rate performance of orthogonal frequency division multiplexing (OFDM) is severely degraded by the deep fading subcarriers. Powerful error-correcting codes must be used with OFDM. This paper presents a quasi-cyclic low-density parity-check (LDPC) coded OFDM system, in which the redundant bits of each codeword are mapped to a higher-order modulation constellation. The optimal degree distribution was calculated using density evolution. The corresponding quasi-cy...

Chinese text categorization differs from English text categorization due to its much larger term set (of words or character n-grams), which results in very slow training and working of modern high-performance classifiers. This study assumes that this high-dimensionality problem is related to the redundancy in the term set, which cannot be solved by traditional term selection methods. A greedy algorithm framework named “non-independent term selection” is presented, which redu...

This paper describes a distributed estimation scheme (DES) for a bandwidth constrained ad hoc sensor network. The DES is universal in the sense that operations on all sensors are identical and independent of noise distribution. The scheme requires each sensor to transmit just a 1-bit message per observation. Simulation results show that the scheme achieves much better mean-squares error (MSE) performance than the simplified isotropic universal DES and even outperforms the isotropic universal DES...

The rapid development of multimedia techniques has increased the demands on multimedia processors. This paper presents a new design method to quickly design high performance processors for new multimedia applications. In this approach, a configurable processor based on the very long instruction-set word architecture is used as the basic core for designers to easily configure new processor cores for multimedia algorithm. Specific instructions designed for multimedia applications efficiently impro...

This paper presents an image-based algorithm for simulating the visual adaptation of the human visual system to various illuminations, especially in dark nighttime conditions. The human visual system exhibits different characteristics depending on the illumination intensity, with photopic vision in bright conditions, scotopic vision in dark conditions, and mesopic vision between these two. A computational model is designed to simulate multiple features of mesopic vision and scotopic vision, incl...

A representation method using the non-symmetry and anti-packing model (NAM) for data compression of binary images is presented. The NAM representation algorithm is compared with the popular linear quadtree and run length encoding algorithms. Theoretical and experimental results show that the algorithm has a higher compression ratio for both lossy and lossless cases of binary images and better reconstructed quality for the lossy case.

As a generalization of orthogonal frequency-division multiplexing (OFDM) systems, multi-input multi-output (MIMO) OFDM systems are very sensitive to carrier frequency offset (CFO). This paper proposes a blind CFO estimation method based on power spectrum analysis, which has high bandwidth efficiency and is much less complex. This method can be used to estimate the residual CFO, which is less than half of the subcarrier spacing. The method uses a cosine cost function to get a closed-form CFO esti...