Lazy AC-Pattern Matching for Rewriting

We define a lazy pattern-matching mechanism modulo associativity and commutativity. The solutions of a pattern-matching problem are stored in a lazy list composed of a first substitution at the head and a non-evaluated object that encodes the remaining computations. We integrate the lazy AC-matching in a strategy language: rewriting rule and strategy application produce a lazy list of terms.Comment: In Proceedings WRS 2011, arXiv:1204.531

TYC 2675-663-1: A newly discovered W UMa system in an active state

The recently discovered eclipsing binary system TYC 2675-663-1 is a X-ray source, and shows properties in the optical that are similar to the W UMa systems, but are somewhat unusual compared to what is seen in other contact binary systems. The goal of this work is to characterize its properties and investigate its nature by means of detailed photometric and spectroscopic observations. We have performed extensive V-band photometric measurements with the INTEGRAL satellite along with ground-based multi-band photometric observations, as well as high-resolution spectroscopic monitoring from which we have measured the radial velocities of the components. These data have been analysed to determine the stellar properties, including the absolute masses and radii. Additional low-resolution spectroscopy was obtained to investigate spectral features. From the measured eclipse timings we determine an orbital period for the binary of P=0.4223576+-0.0000009 days. The light-curve and spectroscopic analyses reveal the observations to be well represented by a model of an overcontact system composed of main-sequence F5 and G7 stars (temperature difference of nearly 1000 K), with the possible presence of a third star. Low-resolution optical spectroscopy reveals a complex H alpha emission, and other features that are not yet understood. The unusually large mass ratio of q=0.81+-0.05 places it in the rare "H" (high mass ratio) subclass of the W UMa systems, which are presumably on their way to coalescence.Comment: 12 pages in double column format. Accepted for publication in Astronomy and Astrophysic

State space c-reductions for concurrent systems in rewriting logic

We present c-reductions, a state space reduction technique. The rough idea is to exploit some equivalence relation on states (possibly capturing system regularities) that preserves behavioral properties, and explore the induced quotient system. This is done by means of a canonizer function, which maps each state into a (non necessarily unique) canonical representative of its equivalence class. The approach exploits the expressiveness of rewriting logic and its realization in Maude to enjoy several advantages over similar approaches: exibility and simplicity in the definition of the reductions (supporting not only traditional symmetry reductions, but also name reuse and name abstraction); reasoning support for checking and proving correctness of the reductions; and automatization of the reduction infrastructure via Maude's meta-programming features. The approach has been validated over a set of representative case studies, exhibiting comparable results with respect to other tools

Semi-automatic extraction of line features from aerial photographs

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:14.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Bu çalışmada; dijital hava fotoğraflarından çizgisel ve alansal detayların sınırlarının ve merkez hatlarının yarı otomatik olarak belirlenmesini sağlayan bir yöntem ve bu yöntemin uygulamaya konmasına yönelik bir yazılım geliştirilmiştir. Geliştirilen yöntem, görüntü bölümleme ve düzey kümesi algoritmalarının birlikte kullanılmasına dayanmaktadır Yöntemin uygulanabilirliğinin araştırılması amacıyla 1:35000 ölçekli siyah beyaz hava fotoğrafı üzerinde yarı otomatik detay çizme işlemleri gerçekleştirilmiştir. Bununla birlikte; İTÜ Ayazağa Kampüsünü içeren renkli ortofoto görüntüler kullanılarak yöntemin doğruluk araştırması yapılmış ve binalarda ± 0.463m, yollarda ise ± 0.663 karesel ortalama hatalar tespit edilmiştir. Yapılan doğruluk araştırması sonucunda, geliştirilen yöntemin, kullanılan dijital hava fotoğrafının  ±1 pikselinin boyutuna eşit olan bir hata kriterine sahip olduğu sonucuna ulaşılmıştır. Bununla birlikte; bu yöntemin fotogrametrik harita üretiminde ve CBS için fotogrametrik veri sağlanmasında yeni bir yöntem olarak kullanılabileceği değerlendirilmiştir. Özellikle: Göller, sulu dereler ve binalar gibi homojen yapıdaki detayların sınırlarına ait vektör verilerin toplanmasında çok başarılı ve etkili bir şekilde kullanılabileceği görülmüştür. İstenildiği takdirde, tolerans değerinin uygun olarak belirlenmesiyle, söz konusu detaylar üzerinde gözle ayırt edilemeyen sınıflandırmalar ve bölümlemeler gerçekleştirilebileceği tespit edilmiştir. Kaliteli yolların sınırları ve/veya merkez hatları (kullanılan fotoğrafın ölçeğine ve mekânsal ayırma gücüne bağlı olarak) etkili ve hızlı bir şekilde çizilebileceği, ayrıca kırıklık toleransı değerleri değiştirilerek istenilen kırıklıkta vektör veriler elde edilebileceği sonucuna varılmıştır. Raster veriden vektör veriye dönüşümde hem sınırların hem de merkez hatların kullanılabilmesinin etkinliğe çok katkı sağlayacağı düşünülmektedir.   Anahtar Kelimeler: Görüntü bölümleme, düzey kümesi, yarı otomatik, dijital hava fotoğrafı.<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:14.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US;} p.zetmetni, li.zetmetni, div.zetmetni {mso-style-name:"Özet metni"; margin-top:6.0pt; margin-right:0cm; margin-bottom:0cm; margin-left:0cm; margin-bottom:.0001pt; text-align:justify; mso-pagination:widow-orphan; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US; font-style:italic; mso-bidi-font-style:normal;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Aerial photographs have been evaluated manually by the operators for a long time for the extraction of the vector data. Computer technology and digital image processing technologies have been developed and this development provides to perform these extraction processes automatically or semi-automatically. Automatic feature extraction studies are firstly motivated to carry out the extraction of roads from digital images because roads have characteristic attributes like width, surface type and geometrical shape which can be modelled more easily than the others. The resolution of the images has a very important role in the automatic and semi-automatic extraction of the roads. Most known methods are based on the road tracing and the snakes algorithms. Another method of automatic and semi-automatic feature extraction and classification of images is the image segmentation. In recent years, image segmentation and the front propagation of the segments have been carried out successfully by the Level Set and Fast Marching methods. In this study, a semi-automatic line extraction method, based on the segmentation of the images using color-differences of the pixels and the propagation of fronts by the Level Set algorithms, is developed. An object-oriented application software is also developed to test the capabilities of the developed method. Some semi-automatic feature extraction applications are made by the help of the developed software using a 1:35000 scale black/white aerial photograph for determining the capabilities of this method.  Another application with 1:5000 scaled two ortho images which have 0.5m resolution of Ayazağa Campus of İstanbul Technical University. These ortho images are generated from 1:16000 scaled color aerial photographs. In this test area, an accuracy test is also carried out to find the accuracy of the developed method. In this accuracy test, vector data of roads and buildings are collected semi-automatically with the developed software and also manually with an experienced operator. The data collected by the operator are assumed the correct ones and they are compared with the others collected by the software. The accuracy test is carried out in two groups. In the first group, on 422 road check points, measurements are made and the square mean root found as ±0.663m. In the second group, buildings are used and 281 check points are measured and the square mean root of this group is equal to ±0.463m.As the results of the applications and tests, it can be said that the accuracy of this developed method is ±1 pixel size of the used imagery. It can be used correctly for producing maps and collecting vector data for GIS. Especially for lakes, rivers and buildings can be collected very efficiently. Different classifications and segmentations, which an operator’s can not see, can be made also with the adjusting of the tolerance value. Roads which have good quality can be vectorized from their center lines and/or boundaries according to the scale of the image used. Some weak sides of this developed method and software are also found out. Especially on big scale aerial photographs, the obstacles on the features, as trees, cars and shadows, effects the extraction of the features negatively. Effects of this factor are reduced whether the scale of the image gets smaller. If the tolerance value is not be adjusted to the correct values, wrong features can be extracted. When a big size image is used, the software gives back some errors because the size of the arrays is directly proportional to the number of the pixels. The quality, contrast and noise of the image effect the feature extraction process. The surface attributes of the features also effect the success degree of the feature extraction. If the noise and the contrast of the images are eliminated by the image process algorithms like edge detection algorithms and filters as anisothropic diffusion and the blanks that are generated by the obstacles on the feature can be interpolated by the different kinds of interpolation methods, more good results can be achieved by the developed method and the software. Also, for the image segmentation different types of segmentation like snakes, instead of color difference and for big size images pyramid levels can be used to increase the success degree of this method.   Keywords: Image segmentation, level set, semi-automatic, digital aerial photograph

Unscheduled DNA synthesis in xeroderma pigmentosum cells after microinjection of yeast photoreactivating enzyme.

Photoreactivating enzyme (PRE) from yeast causes a light-dependent reduction of UV-induced unscheduled DNA synthesis (UDS) when injected into the cytoplasm of repair-proficieint human fibroblasts (Zwetsloot et al., 1985). This result indicates that the exogenous PRE monomerizers UV-induced dimers in these cells competing with the endogenous excision repair. In this paper we present the results of the injection of yeast PRE on (residual) UDS in fibroblasts from different excision-deficient XP-strains representing complementation groups A, C, D, E, F, H and I (all displaying more than 10% of the UDS of wild-type

Optimization of double pulse pumping for Ni-like Sm x-ray lasers

We report a systematic study of double pulse pumping of the Ni-like Sm x-ray laser at 73 Angstrom, currently the shortest wavelength saturated x-ray laser. It is found that the Sm x-ray laser output can change by orders of magnitude when the intensity ratio of the pumping pulses and their relative delay are varied. Optimum pumping conditions are found and interpreted in terms of a simple model. (C) 1999 American Institute of Physics. [S0021-8979(99)07102-9]

A catalog of chromospherically active binary stars (third edition)

Chromospherically Active Binaries (CAB) catalogue have been revised and updated. With 203 new identifications, the number of CAB stars is increased to 409. Catalogue is available in electronic format where each system has various number of lines (sub-orders) with a unique order number. Columns contain data of limited number of selected cross references, comments to explain peculiarities and position of the binarity in case it belongs to a multiple system, classical identifications (RS CVn, BY Dra), brightness and colours, photometric and spectroscopic data, description of emission features (Ca II H&K, $H_{\alpha}$, UV, IR), X-Ray luminosity, radio flux, physical quantities and orbital information, where each basic entry are referenced so users can go original sources.Comment: 5 pages, including 2 figures and 3 tables, accepted for publication in MNRA

Cloning, tissue expression, and mapping of a human photolyase homolog with similarity to plant blue-light receptors

Enzymatic photoreactivation is a DNA repair mechanism that removes UV- induced pyrimidine dimer lesions by action of a single enzyme, photolyase, and visible light. Its presence has been demonstrated in a wide variety of organisms, ranging from simple prokaryotes to higher eukaryotes. We have isolated a human gene encoding a 66-kDa protein that shows clear overall homology to known bacterial photolyase genes. The human gene product is more similar to plant blue-light receptors within class I ph