A new selective retransmission method for HARQ (Hybrid Automatic Repeat reQuest) systems is proposed. This method can avoid the blindness of symbols retransmission by the transformation of lostmap matrix and simulation results show that the proposed method can reduce the number of retransmissions effectively.

In this paper, we propose a coding algorithm for High Dynamic Range Images (HDRI). Our encoder applies a tone mapping model based on scaled µ-Law encoding, followed by a conventional Low Dynamic Range Image (LDRI) encoder. The tone mapping model is designed to minimize the difference between the tone-mapped HDRI and its LDR version. By virtue of the nature of the µ-Law model, not only the quality of the HDRI but also the one of the LDRI is improved, compared with a state of the art in conventional HDRI coding methods. Furthermore the error limit caused by our encoding is theoretically analyzed.

We review our recent work on ultra-long-haul wavelength division multiplexed (WDM) transmission with high spectral efficiency (SE) employing tight pre-filtering and multi-symbol detection. We start the discussion with a theoretical evaluation of the SE limit of pre-filtered modulation in optical fiber communication systems. We show that pre-filtering induced symbol correlation generates a modulation with memory and thus, a higher SE limit than that of the original memory-less modulation. We also investigate the merits of utilizing the pre-filtering induced symbol correlation with multi-symbol detection to achieve high SE transmission. We demonstrate transoceanic WDM transmission of a pre-filtered polarization division multiplexed return-to-zero quaternary phased shift keying (PDM-RZ-QPSK) modulation format with multi-symbol detection, achieving 419% SE which is higher than the SE limit of the original memory-less PDM-RZ-QPSK format.

Recently, we have proposed using a Linear Array Pipeline Processor (LAPP) to improve energy efficiency for various workloads such as image processing and to maintain programmability by working on VLIW codes. In this paper, we proposed an instruction mapping scheme for LAPP to fully exploit the array execution of functional units (FUs) and bypass networks by a mapper to fit the VLIW codes onto the FUs. The mapping can be finished within multi-cycles during a data prefetch before the array execution of FUs. According to an HDL based implementation, the hardware required for mapping scheme is 84% of the cost introduced by a baseline method. In addition, the proposed mapper can further help to shrink the size of array stage, as our results show that their combination becomes 88% of the baseline model in area.

In this paper we propose a new tone mapping method for HDR video. Two types of gamma tone mapping are blended to preserve local contrast in the entire range of luminance. Our method achieves high quality tone mapping especially for the HDR video that has a nonlinear response to scene radiance. Additionally, we apply it to an object-aware tone mapping method for camera surveillance. This method achieves high visibility of target objects in the tone mapped HDR video. We examine the validity of our methods through simulation and comparison with conventional work.

Transmission coordination mechanism (TCM) aids opportunistic routing (OR) to reduce the total number of packet transmissions and improve end-to-end throughput. Existing paradigms based on batch map partitions packets of communication session into segments, and transmit packet segments in batch mode sequentially. However, the rate of successful transmission coordination oscillates due to the oscillation of the number of packets batch transmitted. In this paper, we propose batch sliding window-based TCM to improve the performance of OR. By transmitting packets in continuous batch mode, batch sliding window-based TCM can hold the rate of successful transmission coordination steady. Simulation results show the average end-to-end throughput gain of the proposed TCM is 15.4% over existing batch map-based TCM.

Broadcasting information to users about new resource assignments generates a substantial mapping overhead. The mapping overhead influences the system throughput and, in particular, seriously affects the performance of voice-over-Internet protocol (VoIP) services. Persistent scheduling was introduced to reduce the mapping overhead. However, up to now no studies have mathematically analyzed the performance of the persistent scheduling. This paper develops analytical and simulation models and evaluates the performance of the persistent scheduling for VoIP services in mobile WiMAX systems.

In proxy re-encryption schemes, a semi-trusted entity called a proxy can convert a ciphertext encrypted for Alice into a new ciphertext for Bob without seeing the underlying plaintext. Several proxy re-encryption schemes have been proposed, however, only two schemes which enables the conversion of IBE ciphertexts to PKE ciphertexts has been proposed. One of schemes has some drawbacks such that the size of the re-encrypted ciphertext increases and Bob must be aware of existence of the proxy, which means Bob cannot decrypt a re-encrypted ciphertext with same PKE decryption algorithm. The other one achieves security under Selective-ID model. We propose a new, efficient scheme that enables the conversion of IBE ciphertexts to PKE ciphertexts, and prove full-ID CPA security in the standard model. In our scheme, the size of the re-encrypted ciphertext is optimal and Bob should not aware of existence of the proxy. As far as we know, this is the first IBE-PKE type scheme that holds the above properties.

Pairing-based cryptosystems are generally constructed using many functions such as pairing computation, arithmetic in finite fields, and arithmetic on elliptic curves. MapToPoint, which is a hashing algorithm onto an elliptic curve point, is one of the functions for constructing pairing-based cryptosystems. There are two MapToPoint algorithms on supersingular elliptic curves in characteristic three, which is used by ηT pairing. The first is computed by using a square root computation in F3m, and the computational cost of this algorithm is O(log m) multiplications in F3m. The second is computed by using an (m-1)(m-1) matrix over F3. It can be computed by O(1) multiplications in F3m. However, this algorithm needs the off-line memory to store about m F3m-elements. In this paper, we propose an efficient MapToPoint algorithm on the supersingular elliptic curves in characteristic three by using 1/3-trace over F3m. We propose 1/3-trace over F3m, which can compute solution x of x3 -x = c by using no multiplication in F3m. The proposed algorithm is computed by O(1) multiplications in F3m, and it requires less than m F3-elements to be stored in the off-line memory to efficiently compute trace over F3m. Moreover, in our software implementation of F3509, the proposed MapToPoint algorithm is approximately 35% faster than the conventional MapToPoint algorithm using the square root computation on an AMD Opteron processor (2.2 GHz).

Image registration is an important topic in medical image analysis. It is usually used in 2D mosaics to construct the whole image of a biological specimen or in 3D reconstruction to build up the structure of an examined specimen from a series of microscopic images. Nevertheless, owing to a variety of factors, including microscopic optics, mechanisms, sensors, and manipulation, there may be great differences between the acquired image slices even if they are adjacent. The common differences include the chromatic aberration as well as the geometry discrepancy that is caused by cuts, tears, folds, and deformation. They usually make the registration problem a difficult challenge to achieve. In this paper, we propose an efficient registration method, which consists of a feature-based registration approach based on analytic robust point matching (ARPM) and a refinement procedure of the feature-based Levenberg-Marquardt algorithm (FLM), to automatically reconstruct 3D vessels of the rat brains from a series of microscopic images. The registration algorithm could speedily evaluate the spatial correspondence and geometric transformation between two point sets with different sizes. In addition, to achieve subpixel accuracy, an FLM method is used to refine the registered results. Due to the nonlinear characteristic of FLM method, it converges much faster than most other methods. We evaluate the performance of proposed method by comparing it with well-known thin-plate spline robust point matching (TPS-RPM) algorithm. The results indicate that the ARPM algorithm together with the FLM method is not only a robust but efficient method in image registration.

Time is considered as an important factor in modeling and operation of dynamic systems. However, few studies have considered time factor in modeling and inference of fuzzy cognitive maps (FCMs), besides, no studies have dealt with time delay in learning of FCMs. Therefore, we propose a learning rule for temporal FCMs involving post- and pre-delay time by extending Oja's learning rule. We show the effectiveness of the proposed rule through simulations which solve a time-delayed chemical plant control problem.

The logistic map is a chaotic mapping. Although several studies have examined logistic maps over real domains with infinite/finite precisions, there has been little analysis of the logistic map over integers. Focusing on differences between the logistic map over the real domain with infinite precision and the logistic map over integers with finite precision, we herein show the characteristic properties of the logistic map over integers and discuss the sequences generated by the map.

Fuzzy cognitive maps (FCMs) are used to support decision-making, and the decision processes are performed by inference of FCMs. The inference greatly depends on activation functions such as sigmoid function, hyperbolic tangent function, step function, and threshold linear function. However, the sigmoid functions widely used for decision-making processes have been designed by experts. Therefore, we propose a method for designing sigmoid functions through Lyapunov stability analysis. We show the usefulness of the proposed method through the experimental results in inference of FCMs using the designed sigmoid functions.

This paper presents a visual knowledge structure reasoning method using Intelligent Topic Map which extends the conventional Topic Map in structure and enhances its reasoning functions. Visual knowledge structure reasoning method integrates two types of knowledge reasoning: the knowledge logical relation reasoning and the knowledge structure reasoning. The knowledge logical relation reasoning implements knowledge consistency checking and the implicit associations reasoning between knowledge points. We propose a Knowledge Unit Circle Search strategy for the knowledge structure reasoning. It implements the semantic implication extension, the semantic relevant extension and the semantic class belonging confirmation. Moreover, the knowledge structure reasoning results are visualized using ITM Toolkit. A prototype system of visual knowledge structure reasoning has been implemented and applied to the massive knowledge organization, management and service for education.

A novel Position-Invariant Robust Feature, designated as PIRF, is presented to address the problem of highly dynamic scene recognition. The PIRF is obtained by identifying existing local features (i.e. SIFT) that have a wide baseline visibility within a place (one place contains more than one sequential images). These wide-baseline visible features are then represented as a single PIRF, which is computed as an average of all descriptors associated with the PIRF. Particularly, PIRFs are robust against highly dynamical changes in scene: a single PIRF can be matched correctly against many features from many dynamical images. This paper also describes an approach to using these features for scene recognition. Recognition proceeds by matching an individual PIRF to a set of features from test images, with subsequent majority voting to identify a place with the highest matched PIRF. The PIRF system is trained and tested on 2000+ outdoor omnidirectional images and on COLD datasets. Despite its simplicity, PIRF offers a markedly better rate of recognition for dynamic outdoor scenes (ca. 90%) than the use of other features. Additionally, a robot navigation system based on PIRF (PIRF-Nav) can outperform other incremental topological mapping methods in terms of time (70% less) and memory. The number of PIRFs can be reduced further to reduce the time while retaining high accuracy, which makes it suitable for long-term recognition and localization.

The Hidden Vector Encryption scheme is one of the searchable public key encryption schemes that allow for searching encrypted data. The Hidden Vector Encryption scheme supports conjunctive equality, comparison, and subset queries, as well as arbitrary conjunctive combinations of these queries. In a Hidden Vector Encryption scheme, a receiver generates a token for a vector of searchable components and sends the token to a query server which has the capability to evaluate it on encrypted data. All of the existing Hidden Vector Encryption schemes, which are all pairing-based, require token elements and pairing computations proportional to the number of searchable components in the token. In this paper, we suggest an improved paring-based Hidden Vector Encryption scheme where the token elements and pairing computations are independent of the number of searchable components. Namely, for an arbitrary conjunctive search query, the token is of size O(1) and the query server only needs O(1) pairing computations. The latter improvement in particular might be very attractive to a query server in a larger search system with many users. To achieve our goal, we introduce a novel technique to generate a token, which may be of independent interest.

This paper proposes an efficient adaptive depth-map coding scheme for generating virtual-view images in 3D-video. Virtual-view images can be generated by view-interpolation based on the decoded depth-map of the image. The proposed depth-map coding scheme is designed to have a new gray-coding-based bit-plane coding method for efficiently coding the depth-map images on the object-boundary areas, as well as the conventional DCT-based coding scheme (H.264/AVC) for efficiently coding the inside area images of the objects or the background depth-map images. Simulation results show that the proposed coding scheme, in comparison with the H.264/AVC coding scheme, improves the BD-rate savings 6.77%-10.28% and the BD-PSNR gains 0.42 dB-0.68 dB. It also improves the subjective picture quality of synthesized virtual-view images using decoded depth-maps.

Information on false paths in a circuit is useful for design and testing. The use of this information may contribute not only to reducing circuit area, the time required for logic synthesis, test generation and test application of the circuit, but also to alleviating over-testing. Since identification of the false paths at gate level is hard, several methods using high-level design information have been proposed. These methods are effective only if the correspondence between paths at register transfer level (RTL) and at gate level can be established. Until now, giving restriction on logic synthesis is the only way to establish the correspondence. However, it is not practical for industrial designs. In this paper, we propose a method for mapping RTL false paths to their corresponding gate level paths without such a specific logic synthesis; it guarantees that the corresponding gate level paths are false. Experimental results show that our path mapping method can establish the correspondences of RTL false paths and many gate level false paths.

We exploit a structural knowledge representation scheme called System Entity Structure (SES) methodology to represent and manage wafer failure patterns which can make a significant influence to FABs in the semiconductor industry. It is important for the engineers to simulate various system verification processes by using predefined system entities (e.g., decomposition, taxonomy, and coupling relationships of a system) contained in the SES. For better computational performance, given a certain failure pattern, a Pruned SES (PES) can be extracted by selecting the only relevant system entities from the SES. Therefore, the SES-based simulation system allows the engineers to efficiently evaluate and monitor semiconductor data by i) analyzing failures to find out the corresponding causes and ii) managing historical data related to such failures.

Error-propagation is an important issue and should be carefully coped with in the decision-feedback equalizers (DFE). Ignoring the impact of error-propagation often leads to impractical laboratory results. In this paper, we investigate two novel layered space-frequency equalizers (LSFE) for single-carrier multiple-input multiple-output (MIMO) systems, where the recently proposed frequency-domain equalizer with time domain noise-predictor (FDE-NP) is adopted at each stage of the LSFE. We first derive the partially-connected LSFE with noise predictor (PC-LSFE-NP) which has exactly the same mean square error (MSE) as the conventional LSFE under the assumption of perfect feedback. However, if error-propagation is considered, the proposed PC-LSFE-NP can achieve better performance than the conventional LSFE due to the more reliable feedback output by the decoders. To reduce the interference from the not yet detected layers in the feedback section, we then introduce the fully-connected LSFE with noise predictor (FC-LSFE-NP), in which all layers are implicitly equalized within each stage and their decisions fed back internally. The powerful feedback filter of FC-LSFE-NP brings significant performance superiority over the conventional LSFE and PC-LSFE-NP with either perfect or imperfect feedback. Moreover, we propose a simple soft-demapper for the equalizers to avoid information loss during decoding, and thus, further improve the performance. Finally, we compare the performance of (PC/FC)-LSFE-NP with the existing schemes by computer simulations.