Algoritma Kompresi Fraktal Sequential Dan Paralel Untuk Kompresi Citra

Kompresi citra adalah proses mengurangi ukuran dari citra dengan mengurangi kualitas dari citra tersebut. Metode Fraktal yang digunakan bekerja dengan mencari kemiripan pada piksel-piksel citra dan mengelompokkannya dalam beberapa cluster. Semakin tinggi tingkat kemiripan pada citra, rasio kompresi akan semakin baik. Pada citra berwarna (RGB) metode tersebut diulang sebanyak tiga kali, masing-masing untuk satu elemen warna. Hasil akhir dari proses kompresi adalah tiga virtual codebook, masing-masing untuk satu elemen warna, yang menyimpan nilai dari brightness, contrast, dan tipe transformasi affine yang digunakan untuk tiap cluster. Proses dekompresi dari metode ini adalah dengan membentuk citra kosong dengan resolusi yang sama dengan citra asli dan mengisikan nilai RGB pada tiap piksel yang bersangkutan dengan menghitung nilai yang tersimpan pada virtual codebook. Dengan menggunakan nilai Coefficient of Variation (CV) sebagai penyesuaian nilai standar deviasi dan 57 citra BMP24-bit, hasil pengujian menunjukkan rasio kompresi rata-rata sebesar 41.79%. Dengan metode paralel yang digunakan, proses kompresi citra berwarna menunjukkan rata-rata nilai speed-up sebesar 1.69 dan nilai efisiensi prosesor sebesar 56.34%. Image compression is a process of reducing the size of the image by reducing the quality of the image. Fractal method is used to work by searching for similarities in the image pixels, and group them in clusters. The higher the degree of resemblance to the image, the better the compression ratio. In the color image (RGB) the method is repeated three times, each for one color element.The end result of the compression process is a three virtual codebook, each for one color element, which stores the value of the brightness, contrast, and the type of affine transformation are used for each cluster. Decompression process of this method is to form a blank image with the same resolution with the original image and fill in the RGB values at each pixel corresponding to the count value stored in the virtual codebook.By using the Coefficient of Variation (CV) as an adjustment value and standard deviation of 57 pieces of 24-bit BMP images, test results showed an average compression ratio of 41.79%. With the parallel method is used, the compression process of color image shows the average speed-up values of 1.69 and the processor efficiency of 56.34%

Optimally coherent sets in geophysical flows: A new approach to delimiting the stratospheric polar vortex

The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this letter, we obtain objective estimates of the structure of the polar vortex by introducing a new technique based on transfer operators that aims to find regions with minimal external transport. Applying this new technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This novel computational approach has wide potential application in detecting and analysing mixing structures in a variety of atmospheric, oceanographic, and general fluid dynamical settings

Analysis of vertebral chemistry to assess stock structure in a deep-sea shark, Etmopterus spinax

First published online: October 27, 2016Deep-sea sharks play a valuable ecological role helping maintain food web balance, yet they are vulnerable to commercial fishing because of slow growth rates and low reproductive capacity. Overfishing of sharks can heavily impact marine ecosystems and the fisheries these support. Knowledge of stock structure is integral to sustainable management of fisheries. The present study analysed vertebral chemistry using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to assay concentrations of 7Li, 23Na, 24Mg, 55Mn, 59Co, 60Ni, 63Cu, 66Zn, 85Rb, 88Sr, 138Ba and 208Pb to assess stock structure in a deep-sea shark, Etmopterus spinax, in Norwegian and French waters. Few studies have applied this technique to elasmobranch vertebrae and the present study represents its first application to a deep-sea shark. Three stocks were identified at the regional scale off western Norway, southern Norway, and France. At finer spatial scales there was evidence of strong population mixing. Overall, the general pattern of stock structure outlined herein provides some indication of the spatial scales at which stocks should be viewed as distinct fisheries management units. The identification of an effective multi-element signature for distinguishing E. spinax stocks utilizing Sr, Ba, Mg, Zn and Pb and the methodological groundwork laid in the present study could also expedite future research into stock structure for E. spinax and deep-sea elasmobranchs more generally.Matthew N. McMillan, Christopher Izzo, Claudia Junge, Ole Thomas Albert, Armelle Jung and Bronwyn M. Gillander

Joint system quantum descriptions arising from local quantumness

Bipartite correlations generated by non-signalling physical systems that admit a finite-dimensional local quantum description cannot exceed the quantum limits, i.e., they can always be interpreted as distant measurements of a bipartite quantum state. Here we consider the effect of dropping the assumption of finite dimensionality. Remarkably, we find that the same result holds provided that we relax the tensor structure of space-like separated measurements to mere commutativity. We argue why an extension of this result to tensor representations seems unlikely

Multiplicativity of completely bounded p-norms implies a new additivity result

We prove additivity of the minimal conditional entropy associated with a quantum channel Phi, represented by a completely positive (CP), trace-preserving map, when the infimum of S(gamma_{12}) - S(gamma_1) is restricted to states of the form gamma_{12} = (I \ot Phi)(| psi >< psi |). We show that this follows from multiplicativity of the completely bounded norm of Phi considered as a map from L_1 -> L_p for L_p spaces defined by the Schatten p-norm on matrices; we also give an independent proof based on entropy inequalities. Several related multiplicativity results are discussed and proved. In particular, we show that both the usual L_1 -> L_p norm of a CP map and the corresponding completely bounded norm are achieved for positive semi-definite matrices. Physical interpretations are considered, and a new proof of strong subadditivity is presented.Comment: Final version for Commun. Math. Physics. Section 5.2 of previous version deleted in view of the results in quant-ph/0601071 Other changes mino

The Hilbertian Tensor Norm and Entangled Two-Prover Games

We study tensor norms over Banach spaces and their relations to quantum information theory, in particular their connection with two-prover games. We consider a version of the Hilbertian tensor norm $\gamma_2$ and its dual $\gamma_2^*$ that allow us to consider games with arbitrary output alphabet sizes. We establish direct-product theorems and prove a generalized Grothendieck inequality for these tensor norms. Furthermore, we investigate the connection between the Hilbertian tensor norm and the set of quantum probability distributions, and show two applications to quantum information theory: firstly, we give an alternative proof of the perfect parallel repetition theorem for entangled XOR games; and secondly, we prove a new upper bound on the ratio between the entangled and the classical value of two-prover games.Comment: 33 pages, some of the results have been obtained independently in arXiv:1007.3043v2, v2: an error in Theorem 4 has been corrected; Section 6 rewritten, v3: completely rewritten in order to improve readability; title changed; references added; published versio

Effective quenching and excited-state relaxation of a Cu(I) photosensitizer addressed by time-resolved spectroscopy and TDDFT calculations

© 2018 Elsevier B.V. Homogenous photocatalytic systems based on copper photosensitizers are promising candidates for noble metal free approaches in solar hydrogen generation. To improve their performance, a detailed understanding of the individual steps is needed. Here, we study the interaction of a heteroleptic copper (I) photosensitizer with an iron catalyst by time-resolved spectroscopy and ab initio calculations. The catalyst leads to rather efficient quenching of the 3MLCT state of the copper complex, with a bimolecular rate being about three times smaller than the collision rate. Using control experiments with methyl viologen, an appearing absorption band is assigned to the oxidized copper complex demonstrating that an electron transfer from the sensitizer to the iron catalyst occurs and the system reacts along an oxidative pathway. However, only about 30% of the quenching events result in an electron transfer while the other 70% experience deactivation indicating that the photocatalytic performance might suffer from geminate recombination

Analytical model of brittle destruction based on hypothesis of scale similarity

The size distribution of dust particles in nuclear fusion devices is close to the power function. A function of this kind can be the result of brittle destruction. From the similarity assumption it follows that the size distribution obeys the power law with the exponent between -4 and -1. The model of destruction has much in common with the fractal theory. The power exponent can be expressed in terms of the fractal dimension. Reasonable assumptions on the shape of fragments concretize the power exponent, and vice versa possible destruction laws can be inferred on the basis of measured size distributions.Comment: 10 pages, 3 figure