Meryem Ahmet

• Plovdiv University

Introduction. The use of environmentally-friendly engineering systems including solar energy technologies makes it possible to reduce energy costs and therefore to lower production costs and anthropogenic stress on the environment.Aim of the Study. The authors used innovative techniques to assess the thermal resource potential of solar radiation, t...

Air-Core Permanent Magnet Synchronous Motors (PMSM) machines are becoming known for their higher efficiency, lighter weight designs, and superior performance compared to widely-utilized induction motors. They hold great potential for diverse industrial applications. However, effectively harnessing this potential requires overcoming drive hardware a...

The primary function of the large electrolytic DC-link capacitor in the single-phase input motor drives is to enhance DC voltage stability by minimizing voltage fluctuations. Because they are both bulky and unreliable components, reducing the size of DC-link capacitors or substituting them with significantly low capacitance value film capacitors of...

Despite the widespread use of encryption techniques to provide confidentiality over Internet communications, mobile device users are still susceptible to privacy and security risks. In this paper, a novel Deep Neural Network (DNN) based on a user activity detection framework is proposed to identify fine-grained user activities performed on mobile a...

Context: A multidisciplinary approach has been suggested to be the optimal form of treatment of fibromyalgia (FM). A research focus on nutritional therapy has developed in recent years, and this approach has been more frequently integrated into the recovery plan of patients with FM. Objectives: The interaction between the nutritional status and...

For any finite Galois extension K of Q and any conjugacy class C in Gal(K/Q), we show that there exist infinitely many Carmichael numbers composed solely of primes for which the associated class of Frobenius automorphisms is C. This result implies that for every natural number n there are infinitely many Carmichael numbers of the form a 2 + nb 2 wi...

A robust image watermarking scheme in curvelet domain is proposed. The curvelet transform directly takes edges as the basic representation element; it provides optimally sparse representations of objects along edges. The image is partitioned into blocks and curvelet transform is applied to those blocks with strong edges. The watermark consists of a...

In this paper, a robust block-based watermarking scheme operating in curvelet domain is proposed. Curvelet transform directly take the edge as the basic representation element; it provides optimally sparse representations of objects along a general curve with bounded curvature. The image is partitioned into small blocks; an edge map is computed to...

In this paper, a robust watermarking scheme operating in curvelet domain is proposed. Curvelet transform directly take the edge as the basic representation element; it provides optimally sparse representations of objects along a general curve with bounded curvature. The image is partitioned into small blocks, Unequally-Spaced Fast Fourier Transform...

Objective video quality measurement is a challenging problem in a variety of video processing application ranging from lossy compression to printing. An ideal video quality measure should be able to mimic the human observer. We present a new video quality measure, M-SVD, to evaluate distorted video sequences based on singular value decomposition. A...

This chapter highlights standardized key management in multimedia distribution architectures. In digital distribution networks, copyrighted multimedia content is protected by encryption. There are various digital distribution-namely, cable, satellite, and terrestrial distribution, internet distribution, and distribution in digital home networks. Th...

Robustness is the one of the essential properties of watermarking schemes. It is the ability to detect the watermark after attacks. A DWT-based semi-blind image watermarking scheme leaves out the low pass band, and embeds a pseudo random number (PRN) sequence (i.e., the watermark) in the other three bands into the coefficients that are higher than...

In image authentication research, a common approach is to divide a given image into a number of smaller blocks, and embed a fragile watermark into each block. The modifications can therefore be detected in the blocks that have been tampered with. The literature includes many authentication techniques for detecting modifications only. In this paper,...

The recent advances in the technology, especially in the computer industry and communications, allowed a potentially enormous market for distributing digital multimedia content through the Internet. However, the proliferation of digital documents, multimedia processing tools, and the worldwide availability of Internet access have created an ideal m...

In this paper, we embed the watermark in a tree structure in the Discrete Wavelet Transform domain. For watermark embedding, the two level DWT decomposition of an N×N gray scale image I is computed. The same PRN sequence is embedded into the DWT coefficients higher than a given threshold T 1 in the LL2 and HH2 bands. The watermark is also embedded...

The important criteria used in subjective evaluation of distorted images include the amount of distortion, the type of distortion, and the distribution of error. An ideal image quality measure should, therefore, be able to mimic the human observer. We present a new grayscale image quality measure that can be used as a graphical or a scalar measure...

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Robust image watermarking is the process of embedding an invisible watermark in an image with the purpose of keeping the watermark intact after intentional attacks and normal audio/visual processes. A recent DWT image watermarking paper embeds a PRN sequence as a watermark in three bands, excluding the low pass subband, using coefficients that are...

A recent image quality measure, M-SVD, can express the quality of distorted images either numerically or graphically. Based on the Singular Value Decomposition (SVD), it consistently measures the distortion across different distortion types and within a given distortion type at different distortion levels. The SVD decomposes every real matrix into...

Robust image watermarking is the process of embedding an invisible watermark in an image with the purpose of keeping the watermark intact after intentional attacks and normal audio/visual processes. A recent DWT image watermarking paper embeds a PRN sequence as a watermark in three bands, excluding the low pass subband, using coefficients that are...

Image quality assessment plays a major role in many image processing applications. Although much effort has been made in recent years towards the development of quantitative measures, the relevant literature does not include many papers that have produced accomplished results. Ideally, a useful measure should be easy to compute, independent of view...

Both Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD) have been used as mathematical tools for embedding data into an image. In the DCT-domain, the DCT coefficients are modified by the elements of a pseudo-random sequence of real values. In the SVD domain, a common approach is to modify the singular values by the singular valu...

Robustness is the one of the essential properties of watermarking schemes. It is the ability to detect the watermark after attacks. A DWT-based semi-blind image watermarking scheme leaves out the low pass band, and embeds a pseudo random number (PRN) sequence (i.e., the watermark) in the other three bands into the coefficients that are higher than...

Protection of digital multimedia content has become an increasingly important issue for content owners and service providers. As watermarking is identified as a major technology to achieve copyright protection, the relevant literature includes several distinct approaches for embedding data into a multimedia element. Because of its growing popularit...

Digital watermarking is considered to be a major technology for the protection of multimedia data. Some of the important applications are broadcast monitoring, copyright protection, and access control. In this paper, we present a semi-blind watermarking scheme for embedding a logo in color images using the DFT domain. After computing the DFT of the...

RNA interference (RNAi) acts on long double-stranded RNAs (dsRNAs) in a variety of eukaryotes to generate small interfering RNAs that target homologous messenger RNA, resulting in their destruction. This process is widely used to 'knock-down' the expression of genes of interest to explore phenotypes. In plants, fission yeast, ciliates, flies and ma...

Although semi-blind and blind watermarking schemes based on Discrete Cosine Transform (DCT) or Discrete Wavelet Transform (DWT) are robust to a number of attacks, they fail in the presence of geometric attacks such as rotation, scaling, and translation. The Discrete Fourier Transform (DFT) of a real image is conjugate symmetric, resulting in a symm...

The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution ("piracy"), plagiarism, and misappropriation. Popular Internet software based on a peer-to-peer architecture has bee...

In subjective evaluation of distorted images, human observers usually consider the type of distortion, the amount of distortion, and the distribution of error. We recently proposed an image quality measure, M-SVD, for gray-scale images that can be used as a graphical tool to predict the distortion based on these three factors, and also as a numeric...

Because of the transition from analog to digital technologies, content owners are seeking technologies for the protection of copyrighted multimedia content. Encryption and watermarking are two major tools that can be used to prevent unauthorized consumption and duplication. In this paper, we generalize an idea in a recent paper that embeds a binary...

Protection of digital multimedia content has become an increasingly important issue for content owners and service providers. As watermarking is identified as a major technology to achieve copyright protection, the relevant literature includes several distinct approaches for embedding data into a multimedia element (primarily images, audio, and vid...

Encryption and watermarking are complementary lines of defense in protecting multimedia content. Recent watermarking techniques have therefore been developed independent from encryption techniques. In this paper, we present a hybrid image protection scheme to establish a relation between the data encryption key and the watermark. Prepositioned secr...

The problem of distributing multimedia securely over the Internet is often viewed as an instance of secure multicast communication, in which multicast messages are protected by a group key shared among the group of clients. One important class of key management schemes makes use of a hierarchical key distribution tree. Constructing a hierarchical t...

DWT and DCT domain watermarking schemes are not robust to geometric attacks such as rotation, scaling, and translation. Recent research has therefore focused on DFT-based watermarking because of its properties. In this paper, we generalize a circular watermarking scheme by embedding one watermark in lower frequencies, and another in higher frequenc...

The important criteria used in subjective evaluation of distorted images include the amount of distortion, the type of distortion, and the distribution of error. An ideal image quality measure should therefore be able to mimic the human observer. We present a new image quality measure that can be used as a multidimensional or a scalar measure to pr...

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, tran...

Multicast is an internetwork service that provides efficient delivery of data from a source to multiple receivers. It reduces the bandwidth requirements of the network and the computational overhead of the host devices. This makes mul- ticast an ideal technology for communication among a large group of participants. Secure group communications invo...

Protection of intellectual property is a critical issue in digital multimedia distribution systems. Cryptographic tools are commonly used for secure delivery of content and access keys to consumers via terrestrial, satellite, cable and Internet transmissions. A third requirement is the distribution of the copyright or usage rights associated with t...

In today's digital world, multimedia content is delivered to homes via the Internet, satellite, terrestrial and cable networks. Scrambling is a common approach used by conditional access systems to prevent unauthorized access to audio/visual data. The descrambling keys are securely distributed to the receivers in the same transmission channel. Thei...

In modem electronic distribution networks, message authentication is an important objective of information security. This objective is met by providing the receiver of a message an assurance of the sender’s identity. As physical protection such as sealed envelopes is not possible for messages expressed as binary sequences, digital tools have been d...

Multicast is an internetwork service that provides efficient delivery of data from a source to multiple receivers. It reduces the bandwidth requirements of the network and the computational overhead of the host devices. This makes multicast an ideal technology for communication among a large group of participants. Secure group communications involv...

Scalable video compression is the encoding of a single video stream in multiple layers, each layer with its own bit rate. Because of the computational complexity of full video encryption, partial encryption has emerged as a general trend for both standard and scalable video codecs. Depending on the application, a particular layer of the video strea...

With the advent of digital technologies, many new market opportunities have emerged for content owners, content distributors, and consumer electronics/information technology industries. An essential requirement for developing a thriving marketplace is the protection of copyrighted content in digital form. There are four major stages in the delivery...

Security is an increasingly important attribute for multimedia applications that require prevention of unauthorized access to copyrighted data. Two approaches have been used to protect scalable video content in distribution: Partial encryption and progressive encryption. Partial encryption provides protection for only selected portions of the video...

Digital multimedia content is delivered to homes via the Internet, satellite, terrestrial and cable networks. Scrambling is a common approach used by conditional access systems to prevent unauthorized access to au- dio/visual data. The descrambling keys are securely dis- tributed to the receivers in the same transmission channel. Their protection i...

The security of multimedia data in digital distribution networks is commonly provided by encryption, i.e., the mathematical process that transforms a plaintext message into unintelligible ciphertext. Nevertheless, the classical and modern ciphers have all been developed for the simplest form of multimedia data, i.e., text, and are not appropriate f...

Scalable video compression is the encoding of a single video stream in multiple layers, each layer with its own bit rate. Because of the computational complexity of full video encryption, partial encryption has emerged as a general trend for both standard and scalable video codecs. Depending on the application, a particular layer of the video strea...

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, tran...

A woman was admitted to the hospital because of a mass involving the lower lobe of the left lung and bilateral hilar enlargement. As biopsies and frozen sections showed benign lesions, a radical resection was avoided during thoracic exploration. Histological examination demonstrated a silica-negative anthracotic spindle-cell pseudotumor. Nine month...

Lossy compression drastically reduces the operating costs of digital medical imaging systems by enabling more efficient use of transmission and archival facilities in hospitals and doctor's offices. To be able to develop standards for the application of this technology, reliable tools are needed for measuring the quality of reconstructed images. Am...

A number of quality measures are evaluated for gray scale image compression. They are all bivariate, exploiting the differences between corresponding pixels in the original and degraded images. It is shown that although some numerical measures correlate well with the observers' response for a given compression technique, they are not reliable for a...

Lossy compression drastically reduces the operating costs of digital medical imaging systems by allowing more efficient use of transmission and archival facilities in hospitals and doctors' offices. To be able to develop standards for the application of this technology, reliable tools are needed for measuring the quality of reconstructed images. Am...

Summary form only given. It is necessary to develop a quality measure that is capable of determining (1) the amount of degradation, (2) the type of degradation, and (3) the impact of compression on different frequency ranges, in a reconstructed image. We discuss the development of a new graphical measure based on three criteria. To be able to make...

A new class of quality measures is emerging in the literature for image compression. The measures in this class are graphical, producing multidimensional output that provides more information than scalar measures like MSE. Eskicioglu charts, a recent addition, computes three features for various frequency ranges, and displays them in a bar chart. R...

Steady-state electrical measurements and optical-absorption experiments were performed on 50 nm thick samples of sublimed heavy-fraction rare-earth-element bisphthalocyanines films. From the Arrhenius plot of In Σ(T) (where Σ(T) is the conductivity at temperatureT it was found that two conduction regimes existed. The activation energy of 0.18 eV at...

Electro-initiated polymerization of bis(4-chloro-2, 6-dibromophenoxo)ethylenediamine copper(II) complex was accomplished under N2 at room temperature, either by constant-potential or by constant-current electrolysis. The structural analyses of the polymers were done by 1H-NMR and FTIR spectroscopy, and measurement of molecular weight was done by li...

Although a variety of techniques are available today for gray-scale image compression, a complete evaluation of these techniques cannot be made as there is no single reliable objective criterion for measuring the error in compressed images. The traditional subjective criteria are burdensome, and usually inaccurate or inconsistent. On the other hand...

In contrast to the organized and relatively predictable confines of the factory floor, many harsh environments create difficulties for conventional data acquisition and control systems. Very few systems can perform real-time analysis of the process under scrutiny, except perhaps for certain routine signal processing, such as filtering and spectral...

A rugged, very compact microcomputer, with a co-processor, has been developed for real-time, high-speed monitoring and simulation of field operations. The development of the computer was funded by the Gas Research Institute for supervision of hydraulic fracturing of gas and oil wells. The system handles data acquisition, data basing, running of pro...

Watermarking, the process of embedding data into a multimedia element, can be used primarily for copyright protection and other purposes. The schemes that have recently been proposed modify the pixel values or transform domain coefficients. The Singular Value Decomposition (SVD) is a practical numerical tool with applications in a number of signal...

Protection of digital multimedia content has become an increasingly important issue for content owners and service providers. As watermarking is identified as a major technology to achieve copyright protection, the relevant literature includes several distinct approaches for embedding data into a multimedia element. Because of its growing popularit...

In this paper, we present a new objective quality measure for color images. In any frequency domain transform, the coefficients in different frequency bands have different magnitudes. The 2-dimensional Discrete Wavelet Transform (DWT) separates a given image into four bands: LL, HL, LH, and HH. After applying the DWT to both the original and degrad...

Both Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD) have been used as mathematical tools for embedding data into an image. In this paper, we present a new robust hybrid watermarking scheme based on DCT and SVD. After applying the DCT to the cover image, we map the DCT coefficients in a zig-zag order into four quadrants, and...

In this paper, we use a tree structure to embed the watermark in DWT decomposition. In the watermark embedding algorithm, the RGB image is first converted to the YUV model. After computing the DWT of the luminance layer, the same PRN sequence is embedded into the DWT coefficients higher than a given threshold T1 in the LL2 and HH2 bands. The PRN se...

Robustness of an image watermarking scheme is the ability to detect the watermark after intentional attacks and normal audio/visual processes. A DWT image watermarking paper embeds a PRN sequence as a watermark in three bands, excluding the low pass subband, using coefficients that are higher than a given threshold T1. During watermark detection, a...

In this paper, we generalize an idea in recent paper that embeds a binary pattern in the form of a binary image in the wavelet domain for images. Our generalization includes all four bands (LL, LH, HL and HH) in the DWT for MPEG video sequences. We tested the proposed algorithm against twelve attacks. Embedding the watermark in lower frequencies is...

A DWT-based semi-blind image watermarking scheme leaves out the low pass band, and embeds the watermark in the other three bands into the coefficients that are higher than a given threshold T1. During watermark detection, all the high pass coefficients above another threshold T2 (T2 > T1) are used in correlation with the original watermark (1). In...

A semi-blind image watermarking scheme embeds a pseudo random sequence in all the high pass DWT coefficients above a given threshold T1. The attacked DWT coefficients are then correlated with the original watermark. For watermark detection, all the coefficients higher than another threshold T2 (>T1) are chosen for correlation with the original wate...

Because of large amount of frames, similarity between frames and temporal attacks (frame dropping, frame averaging, frame swapping etc.), video watermarking process is more difficult than image watermarking. Current image watermarking methods cannot solve these difficulties. One of the important issue in digital video watermarking is the methodolog...