This paper presents two halftoning methods to improve efficiency in generating structurally similar halftone images using Structure Similarity Index Measurement (SSIM). Proposed Method I reduces the pixel evaluation area by applying pixel-swapping algorithm within inter-correlated blocks followed by phase block-shifting. The effect of various initial pixel arrangements is also investigated. Proposed Method II further improves efficiency by applying bit-climbing algorithm within inter-correlated blocks of the image. Simulation results show that proposed Method I improves efficiency as well as image quality by using an appropriate initial pixel arrangement. Proposed Method II reaches a better image quality with fewer evaluations than pixel-swapping algorithm used in Method I and the conventional structure aware halftone methods.

This paper presents a new digital signature scheme for computer-aided facsimile systems which directly embeds a signature onto document. We use multiple reference lines which have been scanned just before and modify each distance between changing pels both on the reference line specified by key and on the coding line with a single bit of the signature data. The sender embeds his signature secretly and transfers it, and the recipient makes a check of any forgery on the signature and the document. This scheme is compatible with the CCITT G3 and G4 facsimile standards. The total amount of data transmitted and the image quality are about the same to that of the original document, and thus an attacker may notice that no signature is embedded on the document.

This paper proposes a novel chaotic multiple-bits modulation scheme that uses the parameters in the map as data carrier for chaotic digital communication. Chaotic signals modulated with the parameters corresponding to the information to be transmitted are sent to the receiver. The information sent to the receiver can be decoded by a correlation detector. This scheme can increase the number of transmittable information bit per unit carrier signals by increasing the number of mapping parameters to be used for modulation. We verify the performance of this scheme using bit error rate (BER) through computer simulation. Also, we compare the performance of the proposed method with a conventional single-bit modulation scheme.

This paper proposes a DCT-based steganographic method named StegErmelc in the JPEG domain. Three strategies are proposed, namely (i) edge-like block selection, (ii) recursive matrix encoding, and (iii) largest coefficient serving, to form a novel steganographic method for achieving scalable carrier capacity, low detectability by universal blind steganalyzer, and high image quality, simultaneously. For a given message length, StegErmelc flexibly scales its carrier capacity to accommodate the message while trading off with stego detectability. At full capacity, StegErmelc has comparable carrier capacity relative to the existing methods. When embedding the same amount of information, StegErmelc remarkably reduces the stego detection rate to about 0.3-0.5 lower than that of the existing methods considered, and consequently StegErmelc can withstand blind steganalyzer when embedding up to 0.10 bpc. Under the same condition, StegErmelc produces stego image with quality higher than that of the existing methods considered. Graphical comparison with three additional evaluation metrics is also presented to show the relative performance of StegErmelc with respect to the existing methods considered.

This paper presents a new data hiding scheme under fractal image generation via Fourier filtering method for Computer Graphics (CG) applications. The data hiding operations are achieved in the frequency domain and a method similar to QAM used in digital communication is introduced for efficient embedding in order to explore both phase and amplitude components simultaneously. Consequently, this scheme enables us not only to generate a natural terrain surface without loss of fractalness analogous to the conventional scheme, but also to embed larger amounts of data into an image depending on the fractal dimension. This scheme ensures the correct decoding of the embedded data under lossy data compression such as JPEG by controlling the quantization exponent used in the embedding process.

In this paper we propose an inter-block evaluation method to further reduce evaluation numbers in GA-based image halftoning technique. We design the algorithm to avoid noise in the fitness function by evolving all image blocks concurrently, exploiting the inter-block correlation, and sharing information between neighbor image blocks. The effectiveness of the method when the population and image block size are reduced, and the configuration of selection and genetic operators are investigated in detail. Simulation results show that the proposed method can remarkably reduce the entire evaluation numbers to generate high quality bi-level halftone images by suppressing noise around block boundaries.

In this paper, we focus on an image encryption scheme based on a truncated Baker transformation. The truncated Baker transformation globally preserves the original dynamics of Baker transformation but incorporates a random local rotation operator between two neighbor elements in the mapping domain in order to keep a finite precision. It generates binary sequences (the dynamics of elements) which have statistically good features on ergodicity, mixing and chaotic properties. The image encryption scheme extended from the truncated Baker transformation efficiently shuffles the input gray level image satisfying fundamental conditions on confusion and diffusion required for image encryption schemes. However, this scheme uses many binary sequences and thus needs to keep a large volume of secret keys. In order to solve this problem we introduce Peano space-filling curve in this scheme, which remarkably reduce the key size and mapping iterations without deteriorating good shuffling properties attained by this scheme.

We have successfully developed an optical receiver and a laser driver circuit which were implemented with 0.35 µm GaAs JFETs (junction Field Effect Transistors). The 0.35 µm GaAs. JFET had the typical transconductance of 480 mS/mm with small drain conductance. An interdigit MSM (Metal Semiconductor Metal) -type photodetector and the JFETs were monolithically integrated on a GaAs substrate for the optical receiver. The fabricated optical receiver demonstrated Gb/s operation with a very low power consumption of 8.2 mW. The laser driver circuit operated at up to 4.0 Gb/s.

In this work we give an extension of Kauffman's NK-Landscapes to multiobjective MNK-Landscapes in order to study the effects of epistasis on the performance of multiobjective evolutionary algorithms (MOEAs). This paper focuses on the development of multiobjective random one-bit climbers (moRBCs). We incrementally build several moRBCs and analyze basic working principles of state of the art MOEAs on landscapes of increased epistatic complexity and number of objectives. We specially study the effects of Pareto dominance, non-dominance, and the use of memory and a population to influence the search. We choose an elitist non-dominated sorting multiobjective genetic algorithm (NSGA-II) as a representative of the latest generation of MOEAs and include its results for comparison. We detail the behavior of the climbers and show that population based moRBCs outperform NSGA-II for all values of M and K.

This paper presents an accelerated image halftoning technique using an improved genetic algorithm with tiny populations. The algorithm is based on a new cooperative model for genetic operators in GA. Two kinds of operators are used in parallel to produce offspring: (i) SRM (Self-Reproduction with Mutation) to introduce diversity by means of Adaptive Dynamic-Block (ADB) mutation inducing the appearance of beneficial mutations. (ii) CM (Crossover and Mutation) to promote the increase of beneficial mutations in the population. SRM applies qualitative mutation only to the bits inside a mutation block and controls the required exploration-exploitation balance through its adaptive mechanism. An extinctive selection mechanism subjects SRM's and CM's offspring to compete for survival. The simulation results show that our scheme impressively reduces computer memory and processing time required to obtain high quality halftone images. For example, compared to the conventional image halftoning technique with GA, the proposed algorithm using only a 2% population size required about 15% evaluations to generate high quality images. The results make our scheme appealing for practical implementations of the image halftoning technique using GA.

This paper presents a new data hiding scheme via steganographic image transformation, which is different from conventional data hiding techniques. The transformation is achieved in the frequency domain and the concept of Fourier filtering method is used. An input image is transformed into a fractal image, which can be used in Computer Graphic (CG) applications. One of the main advantages of this scheme is the amount of data to be hidden (embedded) is equal to that of the host signal (generated fractal image) while it is in general limited in the conventional data hiding schemes. Also both the opened fractal image and the hidden original one can be properly used depending on the situation. Unauthorized users will not notice the "secret" original image behind the fractal image, but even if they know that there is a hidden image it will be difficult for them to estimate the original image from the transformed image. Only authorized users who know the proper keys can regenerate the original image. The proposed method is applicable not only as a security tool for multimedia contents on web pages but also as a steganographic secret communication method through fractal images.

In this work, we study on a data encryption scheme based on a shape-variable truncated Baker transformation. First we show statistical properties of the shape-variable truncated Baker transformation. Then we propose a data encryption scheme with this map and verify its performance whether it satisfies fundamental conditions on confusion and diffusion required for data encryption schemes.

This paper describes a new optical label switching technique; wavelength and pilot tone frequency are combined to form labels that are used to control transport network routing. This technique is very attractive for achieving simple nodes that offer extremely rapid forwarding. Experimental results on the discrimination of optical labels and all-optical label conversion are also presented.

In this paper, we propose δ-similar elimination to improve the search performance of multiobjective evolutionary algorithms in combinatorial optimization problems. This method eliminates similar individuals in objective space to fairly distribute selection among the different regions of the instantaneous Pareto front. We investigate four eliminating methods analyzing their effects using NSGA-II. In addition, we compare the search performance of NSGA-II enhanced by our method and NSGA-II enhanced by controlled elitism.

An image halftoning technique that uses a simple GA has proven to be effective generating bi-level halftone images with quality higher than conventional techniques. Many devices are designed to handle more than two halftone levels and a GA based multi-level halftoning technique is desirable. In this paper we extend the bi-level halftoning technique to generate multi-level halftone images. Also we introduce an improved GA (GA-SRM) into the proposed multi-level halftoning technique. Experimental results show that the proposed technique can effectively generate high quality multi-level halftone images and that the inclusion of GA-SRM substantially contributes reducing memory usage and accelerating image generation.

This paper proposes a new service scheme which multiplexes several independent sub-documents onto the main document in a conventional facsimile broadcasting system. These multiplexed facsimile signals are moreover unified besides the voice channels in television system. The scheme does not increase the amount of facsimile signals, thus, it can save the frequency resources and communication channels. In this system, the main facsimile document is open for common subscribers, but the multiplexed sub-documents are delivered only for the special subscribers who are registered to the broadcasting station for each channel.

In this work we study the performance of a distributed GA that incorporates in its core parallel cooperative-competitive genetic operators. A series of controlled experiments are conducted using various large and difficult 0/1 multiple knapsack problems to test the robustness of the distributed GA. Simulation results verify that the proposed distributed GA compared with a canonical distributed GA significantly gains in search speed and convergence reliability with less communication cost for migration.

NK-Landscapes are stochastically generated fitness functions on bit strings, parameterized with N bits and K epistatic interactions between bits. The term epistasis describes nonlinearities in fitness functions due to changes in the values of interacting bits. Empirical studies have shown that the overall performance of random bit climbers on NK-Landscapes is superior to the performance of some simple and enhanced genetic algorithms (GAs). Analytical studies have also lead to suggest that NK-Landscapes may not be appropriate for testing the performance of GAs. In this work we study the effect of selection, drift, mutation, and recombination on NK-Landscapes for N = 96. We take a model of generational parallel varying mutation GA (GA-SRM) and switch on and off its major components to emphasize each of the four processes mentioned above. We observe that using an appropriate selection pressure and postponing drift make GAs quite robust on NK-Landscapes; different to previous studies, even simple GAs with these two features perform better than a random bit climber (RBC+) for a broad range of classes of problems (K 4). We also observe that the interaction of parallel varying mutation with crossover improves further the reliability of the GA, especially for 12 < K < 32. Contrary to intuition, we find that for small K a mutation only evolutionary algorithm (EA) is very effective and crossover may be omitted; but the relative importance of crossover interacting with varying mutation increases with K performing better than mutation alone (K > 12). This work indicates that NK-Landscapes are useful for testing each one of the major processes involved in a GA and for assessing the overall behavior of a GA on complex non-linear problems. This study also gives valuable guidance to practitioners applying GAs to real world problems of how to configure the GA to achieve better results as the non-linearity and complexity of the problem increases.

A halftoning technique that uses a simple GA has proven to be very effective to generate high quality halftone images. Recently, the two major drawbacks of this conventional halftoning technique with GAs, i.e. it uses a substantial amount of computer memory and processing time, have been overcome by using an improved GA (GA-SRM) that applies genetic operators in parallel putting them in a cooperative-competitive stand with each other. The halftoning problem is a true multiobjective optimization problem. However, so far, the GA based halftoning techniques have treated the problem as a single objective optimization problem. In this work, the improved GA-SRM is extended to a multiobjective optimization GA to simultaneously generate halftone images with various combinations of gray level precision and spatial resolution. Simulation results verify that the proposed scheme can effectively generate several high quality images simultaneously in a single run reducing even further the overall processing time.

This paper describes a new optical label switching technique; wavelength and pilot tone frequency are combined to form labels that are used to control transport network routing. This technique is very attractive for achieving simple nodes that offer extremely rapid forwarding. Experimental results on the discrimination of optical labels and all-optical label conversion are also presented.