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Publisher: Springer-Verlag (Total: 2350 journals)

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Showing 1 - 200 of 2350 Journals sorted alphabetically
3D Printing in Medicine     Open Access  
3D Research     Hybrid Journal   (Followers: 20, SJR: 0.214, h-index: 10)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.073, h-index: 25)
AAPS J.     Hybrid Journal   (Followers: 21, SJR: 1.192, h-index: 74)
AAPS PharmSciTech     Hybrid Journal   (Followers: 7, SJR: 0.718, h-index: 54)
Abdominal Imaging     Hybrid Journal   (Followers: 14, SJR: 0.723, h-index: 60)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.447, h-index: 12)
Academic Psychiatry     Full-text available via subscription   (Followers: 23, SJR: 0.492, h-index: 32)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.135, h-index: 6)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26, SJR: 0.378, h-index: 30)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.355, h-index: 20)
Acoustics Australia     Hybrid Journal  
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.387, h-index: 6)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 34)
Acta Biotheoretica     Hybrid Journal   (Followers: 4, SJR: 0.419, h-index: 25)
Acta Diabetologica     Hybrid Journal   (Followers: 17, SJR: 1.318, h-index: 46)
Acta Endoscopica     Hybrid Journal   (Followers: 1, SJR: 0.113, h-index: 8)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.465, h-index: 23)
Acta Geochimica     Hybrid Journal   (Followers: 6)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2, SJR: 0.294, h-index: 13)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.818, h-index: 22)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 32)
Acta Mathematica     Hybrid Journal   (Followers: 12, SJR: 8.021, h-index: 47)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.53, h-index: 29)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.406, h-index: 30)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.451, h-index: 5)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.22, h-index: 20)
Acta Mechanica     Hybrid Journal   (Followers: 21, SJR: 0.898, h-index: 52)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.426, h-index: 29)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7, SJR: 0.525, h-index: 18)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.524, h-index: 14)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.833, h-index: 73)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 1, SJR: 0.348, h-index: 27)
Acta Neuropathologica     Hybrid Journal   (Followers: 5, SJR: 6.61, h-index: 117)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 17)
Acta Parasitologica     Hybrid Journal   (Followers: 10, SJR: 0.581, h-index: 28)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.551, h-index: 39)
Acta Politica     Hybrid Journal   (Followers: 13, SJR: 0.658, h-index: 20)
Activitas Nervosa Superior     Hybrid Journal  
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 6, SJR: 0.103, h-index: 4)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 22, SJR: 0.871, h-index: 15)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 15, SJR: 0.795, h-index: 40)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.774, h-index: 52)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.319, h-index: 15)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 36, SJR: 0.959, h-index: 44)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19, SJR: 1.255, h-index: 44)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51, SJR: 1.113, h-index: 14)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.141, h-index: 3)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 27, SJR: 1.397, h-index: 42)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.2, h-index: 4)
Advances in Polymer Science     Hybrid Journal   (Followers: 43, SJR: 0.637, h-index: 89)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 0.79, h-index: 44)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.882, h-index: 23)
Aerobiologia     Hybrid Journal   (Followers: 3, SJR: 0.511, h-index: 36)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 9, SJR: 0.821, h-index: 49)
African Archaeological Review     Hybrid Journal   (Followers: 16, SJR: 0.612, h-index: 24)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.248, h-index: 6)
AGE     Hybrid Journal   (Followers: 7, SJR: 1.358, h-index: 33)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.337, h-index: 10)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.529, h-index: 55)
Agricultural Research     Hybrid Journal   (Followers: 4)
Agriculture and Human Values     Hybrid Journal   (Followers: 14, SJR: 1.197, h-index: 49)
Agroforestry Systems     Hybrid Journal   (Followers: 19, SJR: 0.64, h-index: 56)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 11, SJR: 1.732, h-index: 59)
AI & Society     Hybrid Journal   (Followers: 8, SJR: 0.171, h-index: 19)
AIDS and Behavior     Hybrid Journal   (Followers: 13, SJR: 2.006, h-index: 71)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.706, h-index: 19)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 5, SJR: 0.566, h-index: 18)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.388, h-index: 22)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 0.868, h-index: 20)
Algorithmica     Hybrid Journal   (Followers: 8, SJR: 0.898, h-index: 56)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.183, h-index: 20)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 0.729, h-index: 20)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3, SJR: 1.392, h-index: 32)
AMBIO     Hybrid Journal   (Followers: 11, SJR: 1.094, h-index: 87)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 16, SJR: 0.864, h-index: 39)
American J. of Community Psychology     Hybrid Journal   (Followers: 27, SJR: 1.237, h-index: 83)
American J. of Criminal Justice     Hybrid Journal   (Followers: 8, SJR: 0.634, h-index: 13)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 15, SJR: 0.283, h-index: 3)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.175, h-index: 13)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.558, h-index: 35)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 20, SJR: 0.293, h-index: 13)
American Sociologist     Hybrid Journal   (Followers: 12, SJR: 0.18, h-index: 13)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.362, h-index: 83)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.21, h-index: 37)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 5)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 1.096, h-index: 123)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.301, h-index: 26)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.212, h-index: 69)
Animal Cognition     Hybrid Journal   (Followers: 18, SJR: 1.122, h-index: 55)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.156, h-index: 4)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.377, h-index: 32)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.504, h-index: 14)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.167, h-index: 26)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.182, h-index: 94)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.849, h-index: 15)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.857, h-index: 40)
Annals of Finance     Hybrid Journal   (Followers: 29, SJR: 0.686, h-index: 14)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.929, h-index: 57)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.136, h-index: 23)
Annals of Hematology     Hybrid Journal   (Followers: 16, SJR: 1.117, h-index: 62)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.593, h-index: 42)
Annals of Microbiology     Hybrid Journal   (Followers: 10, SJR: 0.402, h-index: 26)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 4, SJR: 0.68, h-index: 45)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.186, h-index: 78)
Annals of Ophthalmology     Hybrid Journal   (Followers: 12)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.405, h-index: 42)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.553, h-index: 8)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 14, SJR: 1.902, h-index: 127)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.315, h-index: 25)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.931, h-index: 31)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.992, h-index: 87)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.14, h-index: 57)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.554, h-index: 87)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.354, h-index: 27)
Applications of Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.274, h-index: 20)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42, SJR: 0.575, h-index: 80)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16, SJR: 0.267, h-index: 26)
Applied Cancer Research     Open Access  
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.361, h-index: 21)
Applied Composite Materials     Hybrid Journal   (Followers: 49, SJR: 0.705, h-index: 35)
Applied Entomology and Zoology     Partially Free   (Followers: 3, SJR: 0.554, h-index: 34)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.323, h-index: 9)
Applied Geophysics     Hybrid Journal   (Followers: 8, SJR: 0.541, h-index: 13)
Applied Intelligence     Hybrid Journal   (Followers: 11, SJR: 0.777, h-index: 43)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.358, h-index: 34)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 6, SJR: 0.955, h-index: 33)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.275, h-index: 8)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.37, h-index: 26)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 63, SJR: 1.262, h-index: 161)
Applied Physics A     Hybrid Journal   (Followers: 9, SJR: 0.535, h-index: 121)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 24, SJR: 0.983, h-index: 104)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.677, h-index: 47)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 11, SJR: 0.288, h-index: 15)
Applied Solar Energy     Hybrid Journal   (Followers: 18, SJR: 0.251, h-index: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.351, h-index: 9)
Aquaculture Intl.     Hybrid Journal   (Followers: 22, SJR: 0.613, h-index: 40)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 33, SJR: 0.646, h-index: 44)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.764, h-index: 39)
Aquatic Sciences     Hybrid Journal   (Followers: 13, SJR: 1.172, h-index: 53)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.345, h-index: 20)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.417, h-index: 16)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 20, SJR: 1.056, h-index: 15)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.397, h-index: 13)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.597, h-index: 29)
Archival Science     Hybrid Journal   (Followers: 58, SJR: 0.804, h-index: 22)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 8, SJR: 0.28, h-index: 15)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 2, SJR: 0.946, h-index: 23)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 4.091, h-index: 66)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.865, h-index: 40)
Archives and Museum Informatics     Hybrid Journal   (Followers: 143)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5, SJR: 2.841, h-index: 40)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 0.9, h-index: 65)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.846, h-index: 84)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.695, h-index: 47)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.702, h-index: 85)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 56)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 1.092, h-index: 13)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 10, SJR: 1.198, h-index: 74)
Archives of Toxicology     Hybrid Journal   (Followers: 17, SJR: 1.595, h-index: 76)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 1.086, h-index: 90)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 14, SJR: 1.264, h-index: 50)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 1.2, h-index: 42)
ArgoSpine News & J.     Hybrid Journal   (SJR: 0.102, h-index: 3)
Argumentation     Hybrid Journal   (Followers: 5, SJR: 0.295, h-index: 18)
Arid Ecosystems     Hybrid Journal   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.948, h-index: 22)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.797, h-index: 17)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.145, h-index: 8)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 11, SJR: 0.288, h-index: 25)
Artificial Intelligence Review     Hybrid Journal   (Followers: 14, SJR: 0.948, h-index: 48)
Artificial Life and Robotics     Hybrid Journal   (Followers: 9, SJR: 0.231, h-index: 14)
Asia Europe J.     Hybrid Journal   (Followers: 5, SJR: 0.247, h-index: 9)
Asia Pacific Education Review     Hybrid Journal   (Followers: 11, SJR: 0.371, h-index: 17)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.676, h-index: 50)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 12, SJR: 0.353, h-index: 13)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.19, h-index: 15)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 19, SJR: 1.006, h-index: 14)
Asian Business & Management     Hybrid Journal   (Followers: 9, SJR: 0.41, h-index: 10)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 9)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.263, h-index: 8)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.681, h-index: 15)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.195, h-index: 5)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  

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Journal Cover Algorithmica
  [SJR: 0.898]   [H-I: 56]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1432-0541 - ISSN (Online) 0178-4617
   Published by Springer-Verlag Homepage  [2350 journals]
  • Guest Editorial: Special Issue on Compact Data Structures
    • Authors: Travis Gagie; Gonzalo Navarro
      Pages: 1983 - 1985
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0381-6
      Issue No: Vol. 80, No. 7 (2018)
       
  • LZ77 Computation Based on the Run-Length Encoded BWT
    • Authors: Alberto Policriti; Nicola Prezza
      Pages: 1986 - 2011
      Abstract: Computing the LZ77 factorization is a fundamental task in text compression and indexing, being the size z of this compressed representation closely related to the self-repetitiveness of the text. A long-standing problem is to compute LZ77 using small working space. Considering that \(\mathcal {O}(z)\) words of space can be significantly (up to exponentially) smaller than the size n of the input text, even succinct and entropy-compressed solutions are often unduly memory demanding. In this work we focus on an important measure of text repetitiveness: the number \(r\) of equal-letter runs in the Burrows–Wheeler transform of the reversed input text. As z, the measure \(r\) is closely related to the number of repetitions in the text and can be exponentially smaller than n. We describe two algorithms computing LZ77 in \(\mathcal {O}(r\log n)\) bits of working space and \(\mathcal {O}(n\log r)\) time. Roughly speaking, our algorithms store a constant number of memory words per BWT run to keep track of first-last run-positions and a suitable indexing mechanism to sample the runs of the BWT (instead of its positions). Important consequences of our results include (i) the possibility to convert from RLBWT- to LZ77-based compressed formats without first decompressing the text, and (ii) the existence of asymptotically-optimal construction algorithms for repetition-aware self-indexes based on these compression techniques. We finally describe an implementation of our solutions and present extensive experiments on highly repetitive datasets. Our algorithms use a working space as small as 1% of the dataset size and are two to three orders of magnitude more space-efficient (albeit slower) than existing solutions based, respectively, on entropy compression and suffix arrays.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0327-z
      Issue No: Vol. 80, No. 7 (2018)
       
  • Lempel–Ziv-78 Compressed String Dictionaries
    • Authors: Julian Arz; Johannes Fischer
      Pages: 2012 - 2047
      Abstract: String dictionaries store a collection \(\left( s_i\right) _{0\le i < m}\) of m variable-length keys (strings) over an alphabet \(\varSigma \) and support the operations lookup (given a string \(s\in \varSigma ^*\) , decide if \(s_i=s\) for some i, and return this i) and access (given an integer \(0\le i < m\) , return the string \(s_i\) ). We show how to modify the Lempel–Ziv-78 data compression algorithm to store the strings space-efficiently and support the operations lookup and access in optimal time. Our approach is validated experimentally on dictionaries of up to 1.5 GB of uncompressed text. We achieve compression ratios often outperforming the existing alternatives, especially on dictionaries containing many repeated substrings. Our query times remain competitive.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0348-7
      Issue No: Vol. 80, No. 7 (2018)
       
  • Lempel–Ziv Factorization Powered by Space Efficient Suffix Trees
    • Authors: Johannes Fischer; Tomohiro I; Dominik Köppl; Kunihiko Sadakane
      Pages: 2048 - 2081
      Abstract: We show that both the Lempel–Ziv-77 and the Lempel–Ziv-78 factorization of a text of length n on an integer alphabet of size \(\sigma \) can be computed in \(\mathop {}\mathopen {}\mathcal {O}\mathopen {}\left( n\right) \) time with either \(\mathop {}\mathopen {}\mathcal {O}\mathopen {}\left( n \lg \sigma \right) \) bits of working space, or \((1+\epsilon ) n \lg n + \mathop {}\mathopen {}\mathcal {O}\mathopen {}\left( n\right) \) bits (for a constant \(\epsilon >0\) ) of working space (including the space for the output, but not the text).
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0333-1
      Issue No: Vol. 80, No. 7 (2018)
       
  • Constant-Time Tree Traversal and Subtree Equality Check for
           Grammar-Compressed Trees
    • Authors: Markus Lohrey; Sebastian Maneth; Carl Philipp Reh
      Pages: 2082 - 2105
      Abstract: A linear space data structure for grammar-compressed trees is presented which allows to carry out tree traversal operations and subtree equality checks in constant time. A traversal step consists of moving to the parent or to the ith child of a node.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0331-3
      Issue No: Vol. 80, No. 7 (2018)
       
  • Compact Representation of Graphs of Small Clique-Width
    • Authors: Shahin Kamali
      Pages: 2106 - 2131
      Abstract: The notion of clique-width for graphs offers many research topics and has received considerable attention in the past decade. A graph has clique-width k if it can be represented as an algebraic expression on k labels associated with its vertices. Many computationally hard problems can be solved in polynomial time for graphs of bounded clique-width. Interestingly also, many graph families have bounded clique-width. In this paper, we consider the problem of preprocessing a graph of size n and clique-width k to build space-efficient data structures that support basic graph navigation queries. First, by way of a counting argument, which is of interest in its own right, we prove the space requirement of any representation is \(\varOmega (kn)\) . Then we present a navigation oracle which answers adjacency query in constant time and neighborhood queries in constant time per neighbor. This oracle uses O(kn) space (i.e., O(kn) bits). We also present a degree query which reports the degree of each given vertex in \(O(k\log ^*(n))\) time using \(O(kn \log ^*(n))\) bits.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0365-6
      Issue No: Vol. 80, No. 7 (2018)
       
  • Editorial: Special Issue on Algorithms and Computation
    • Authors: Seok-Hee Hong
      Pages: 2132 - 2133
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-018-0438-1
      Issue No: Vol. 80, No. 7 (2018)
       
  • Optimal Composition Ordering Problems for Piecewise Linear Functions
    • Authors: Yasushi Kawase; Kazuhisa Makino; Kento Seimi
      Pages: 2134 - 2159
      Abstract: In this paper, we introduce maximum composition ordering problems. The input is n real functions \(f_1,\dots ,f_n:\mathbb {R}\rightarrow \mathbb {R}\) and a constant \(c\in \mathbb {R}\) . We consider two settings: total and partial compositions. The maximum total composition ordering problem is to compute a permutation \(\sigma :[n]\rightarrow [n]\) which maximizes \(f_{\sigma (n)}\circ f_{\sigma (n-1)}\circ \dots \circ f_{\sigma (1)}(c)\) , where \([n]=\{1,\dots ,n\}\) . The maximum partial composition ordering problem is to compute a permutation \(\sigma :[n]\rightarrow [n]\) and a nonnegative integer \(k~(0\le k\le n)\) which maximize \(f_{\sigma (k)}\circ f_{\sigma (k-1)}\circ \dots \circ f_{\sigma (1)}(c)\) . We propose \(\mathrm {O}(n\log n)\) time algorithms for the maximum total and partial composition ordering problems for monotone linear functions \(f_i\) , which generalize linear deterioration and shortening models for the time-dependent scheduling problem. We also show that the maximum total composition ordering problem can be solved in polynomial time if \(f_i\) is of the form \(\max \{a_ix+b_i,d_i,x\}\) for some constants \(a_i\,(\ge 0)\) , \(b_i\) and \(d_i\) . As a corollary, we show that the two-valued free-order secretary problem can be solved in polynomial time. We finally prove that there exists no constant-factor approximation algorithm for the problems, even if \(f_i\) ’s are monotone, piecewise linear functions with at most two pieces, unless P  \(=\)  NP.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0397-y
      Issue No: Vol. 80, No. 7 (2018)
       
  • Degree-Constrained Orientation of Maximum Satisfaction: Graph Classes and
           Parameterized Complexity
    • Authors: Hans L. Bodlaender; Hirotaka Ono; Yota Otachi
      Pages: 2160 - 2180
      Abstract: The problem Max W-Light (Max W-Heavy) for an undirected graph is to assign a direction to each edge so that the number of vertices of outdegree at most W (resp. at least W) is maximized. It is known that these problems are NP-hard even for fixed W. For example, Max 0-Light is equivalent to the problem of finding a maximum independent set. In this paper, we show that for any fixed constant W, Max W-Heavy can be solved in linear time for hereditary graph classes for which treewidth is bounded by a function of degeneracy. We show that such graph classes include chordal graphs, circular-arc graphs, d-trapezoid graphs, chordal bipartite graphs, and graphs of bounded clique-width. To have a polynomial-time algorithm for Max W-Light, we need an additional condition of a polynomial upper bound on the number of potential maximal cliques to apply the metatheorem by Fomin et al. (SIAM J Comput 44:54–87, 2015). The aforementioned graph classes, except bounded clique-width graphs, satisfy such a condition. For graphs of bounded clique-width, we present a dynamic programming approach not using the metatheorem to show that it is actually polynomial-time solvable for this graph class too. We also study the parameterized complexity of the problems and show some tractability and intractability results.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0399-9
      Issue No: Vol. 80, No. 7 (2018)
       
  • On (1, $$\epsilon $$ ϵ )-Restricted Max–Min Fair Allocation Problem
    • Authors: T.-H. Hubert Chan; Zhihao Gavin Tang; Xiaowei Wu
      Pages: 2181 - 2200
      Abstract: We study the max–min fair allocation problem in which a set of m indivisible items are to be distributed among n agents such that the minimum utility among all agents is maximized. In the restricted setting, the utility of each item j on agent i is either 0 or some non-negative weight \(w_j\) . For this setting, Asadpour et al. (ACM Trans Algorithms 8(3):24, 2012) showed that a certain configuration-LP can be used to estimate the optimal value to within a factor of \(4+\delta \) , for any \(\delta >0\) , which was recently extended by Annamalai et al. (in: Indyk (ed) Proceedings of the twenty-sixth annual ACMSIAM symposium on discrete algorithms, SODA 2015, San Diego, CA, USA, January 4–6, 2015) to give a polynomial-time 13-approximation algorithm for the problem. For hardness results, Bezáková and Dani (SIGecom Exch 5(3):11–18, 2005) showed that it is \(\mathsf {NP}\) -hard to approximate the problem within any ratio smaller than 2. In this paper we consider the \((1,\epsilon )\) -restricted max–min fair allocation problem in which each item j is either heavy \((w_j = 1)\) or light \((w_j = \epsilon )\) , for some parameter \(\epsilon \in (0,1)\) . We show that the \((1,\epsilon )\) -restricted case is also \(\mathsf {NP}\) -hard to approximate within any ratio smaller than 2. Using the configuration-LP, we are able to estimate the optimal value of the problem to within a factor of \(3+\delta \) , for any \(\delta >0\) . Extending this idea, we also obtain a quasi-polynomial time \((3+4\epsilon )\) -approximation algorithm and a polynomial time 9-approximation algorithm. Moreover, we show that as \(\epsilon \) tends to 0, the approximation ratio of our polynomial-time algorithm approaches \(3+2\sqrt{2}\approx 5.83\) .
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-018-0407-8
      Issue No: Vol. 80, No. 7 (2018)
       
  • The Subset Assignment Problem for Data Placement in Caches
    • Authors: Shahram Ghandeharizadeh; Sandy Irani; Jenny Lam
      Pages: 2201 - 2220
      Abstract: We introduce the subset assignment problem in which items of varying sizes are placed in a set of bins with limited capacity. Items can be replicated and placed in any subset of the bins. Each (item, subset) pair has an associated cost. Not assigning an item to any of the bins is not free in general and can potentially be the most expensive option. The goal is to minimize the total cost of assigning items to subsets without exceeding the bin capacities. The subset assignment problem models the problem of managing a cache composed of banks of memory with varying cost/performance specifications. The ability to replicate a data item in more than one memory bank can benefit the overall performance of the system with a faster recovery time in the event of a memory failure. For this setting, the number n of data objects (items) is very large and the number d of memory banks (bins) is a small constant (on the order of 3 or 4). Therefore, the goal is to determine an optimal assignment in time that minimizes dependence on n. The integral version of this problem is NP-hard since it is a generalization of the knapsack problem. We focus on an efficient solution to the LP relaxation as the number of fractionally assigned items will be at most d. If the data objects are small with respect to the size of the memory banks, the effect of excluding the fractionally assigned data items from the cache will be small. We give an algorithm that solves the LP relaxation and runs in time \(O(\left( {\begin{array}{c}3^d\\ d+1\end{array}}\right) {\text {poly}}(d) n \log (n) \log (nC) \log (Z))\) , where Z is the maximum item size and C the maximum storage cost.
      PubDate: 2018-07-01
      DOI: 10.1007/s00453-017-0403-4
      Issue No: Vol. 80, No. 7 (2018)
       
  • Guest Editorial: Special Issue on Combinatorial Optimization and
           Applications
    • Authors: Zaixin Lu; Donghyun Kim
      Pages: 1769 - 1770
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-018-0430-9
      Issue No: Vol. 80, No. 6 (2018)
       
  • Scaffolding Problems Revisited: Complexity, Approximation and Fixed
           Parameter Tractable Algorithms, and Some Special Cases
    • Authors: Mathias Weller; Annie Chateau; Clément Dallard; Rodolphe Giroudeau
      Pages: 1771 - 1803
      Abstract: This paper is devoted to new results about the scaffolding problem, an integral problem of genome inference in bioinformatics. The problem consists in finding a collection of disjoint cycles and paths covering a particular graph called the “scaffold graph”. We examine the difficulty and the approximability of the scaffolding problem in special classes of graphs, either close to trees, or very dense. We propose negative and positive results, exploring the frontier between difficulty and tractability of computing and/or approximating a solution to the problem. Also, we explore a new direction through related problems consisting in finding a family of edges having a strong effect on solution weight.
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-018-0405-x
      Issue No: Vol. 80, No. 6 (2018)
       
  • Discovering Small Target Sets in Social Networks: A Fast and Effective
           Algorithm
    • Authors: Gennaro Cordasco; Luisa Gargano; Marco Mecchia; Adele A. Rescigno; Ugo Vaccaro
      Pages: 1804 - 1833
      Abstract: Given a network represented by a graph \(G=(V,E)\) , we consider a dynamical process of influence diffusion in G that evolves as follows: Initially only the nodes of a given \(S\subseteq V\) are influenced; subsequently, at each round, the set of influenced nodes is augmented by all the nodes in the network that have a sufficiently large number of already influenced neighbors. The question is to determine a small subset of nodes S (a target set) that can influence the whole network. This is a widely studied problem that abstracts many phenomena in the social, economic, biological, and physical sciences. It is known that the above optimization problem is hard to approximate within a factor of \(2^{\log ^{1-\epsilon } V }\) , for any \(\epsilon >0\) . In this paper, we present a fast and surprisingly simple algorithm that exhibits the following features: (1) when applied to trees, cycles, or complete graphs, it always produces an optimal solution (i.e, a minimum size target set); (2) when applied to arbitrary networks, it always produces a solution of cardinality which improves on previously known upper bounds; (3) when applied to real-life networks, it always produces solutions that substantially outperform the ones obtained by previously published algorithms (for which no proof of optimality or performance guarantee is known in any class of graphs).
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-017-0390-5
      Issue No: Vol. 80, No. 6 (2018)
       
  • Optimal Approximation Algorithms for Maximum Distance-Bounded Subgraph
           Problems
    • Authors: Yuichi Asahiro; Yuya Doi; Eiji Miyano; Kazuaki Samizo; Hirotaka Shimizu
      Pages: 1834 - 1856
      Abstract: In this paper we study the (in)approximability of two distance-based relaxed variants of the maximum clique problem (Max Clique), named Max d-Clique and Max d-Club: A d-clique in a graph \(G = (V, E)\) is a subset \(S\subseteq V\) of vertices such that for every pair of vertices \(u, v\in S\) , the distance between u and v is at most d in G. A d-club in a graph \(G = (V, E)\) is a subset \(S'\subseteq V\) of vertices that induces a subgraph of G of diameter at most d. Given a graph G with n vertices, the goal of Max d-Clique (Max d-Club, resp.) is to find a d-clique (d-club, resp.) of maximum cardinality in G. Since Max 1-Clique and Max 1-Club are identical to Max Clique, the inapproximabilty for Max Clique shown by Zuckerman in 2007 is transferred to them. Namely, Max 1-Clique and Max 1-Club cannot be efficiently approximated within a factor of \(n^{1-\varepsilon }\) for any \(\varepsilon > 0\) unless \(\mathcal{P} = \mathcal{NP}\) . Also, in 2002, Marin \(\breve{\mathrm{c}}\) ek and Mohar showed that it is \(\mathcal{NP}\) -hard to approximate Max d-Club to within a factor of \(n^{1/3-\varepsilon }\) for any \(\varepsilon >0\) and any fixed \(d\ge 2\) . In this paper, we strengthen the hardness result; we prove that, for any \(\varepsilon > 0\) and any fixed \(d\ge 2\) , it is \(\mathcal{NP}\) -hard to approximate Max d-Club to within a factor of \(n^{1/2-\varepsilon }\) . Then, we design a polynomial-time algorithm which achieves an optimal approximation ratio of
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-017-0344-y
      Issue No: Vol. 80, No. 6 (2018)
       
  • Deleting Edges to Restrict the Size of an Epidemic: A New Application for
           Treewidth
    • Authors: Jessica Enright; Kitty Meeks
      Pages: 1857 - 1889
      Abstract: Motivated by applications in network epidemiology, we consider the problem of determining whether it is possible to delete at most k edges from a given input graph (of small treewidth) so that the resulting graph avoids a set \(\mathcal {F}\) of forbidden subgraphs; of particular interest is the problem of determining whether it is possible to delete at most k edges so that the resulting graph has no connected component of more than h vertices, as this bounds the worst-case size of an epidemic. While even this special case of the problem is NP-complete in general (even when \(h=3\) ), we provide evidence that many of the real-world networks of interest are likely to have small treewidth, and we describe an algorithm which solves the general problem in time \(2^{O( \mathcal {F} w^r)}n\)  on an input graph having n vertices and whose treewidth is bounded by a fixed constant w, if each of the subgraphs we wish to avoid has at most r vertices. For the special case in which we wish only to ensure that no component has more than h vertices, we improve on this to give an algorithm running in time \(O((wh)^{2w}n)\) , which we have implemented and tested on real datasets based on cattle movements.
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-017-0311-7
      Issue No: Vol. 80, No. 6 (2018)
       
  • Structural and Algorithmic Properties of 2-Community Structures
    • Authors: Cristina Bazgan; Janka Chlebikova; Thomas Pontoizeau
      Pages: 1890 - 1908
      Abstract: We investigate the structural and algorithmic properties of 2-community structures in graphs introduced recently by Olsen (Math Soc Sci 66(3):331–336, 2013). A 2-community structure is a partition of a vertex set into two parts such that for each vertex the numbers of neighbours in/outside its own part and the sizes of the parts are correlated. We show that some well studied graph classes as graphs of maximum degree 3, minimum degree at least \( V -3\) , trees and also others, have always a 2-community structure. Furthermore, a 2-community structure can be found in polynomial time in all these classes, even with additional request of connectivity in both parts. We introduce a concept of a weak 2-community and prove that in general graphs it is NP-complete to find a balanced weak 2-community structure with or without request for connectivity in both parts. On the other hand, we present a polynomial-time algorithm to solve the problem (without the condition for connectivity of parts) in graphs of degree at most 3.
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-017-0283-7
      Issue No: Vol. 80, No. 6 (2018)
       
  • Optimal Self-Assembly of Finite Shapes at Temperature 1 in 3D
    • Authors: David Furcy; Scott M. Summers
      Pages: 1909 - 1963
      Abstract: Tile self-assembly in which tiles may bind in a non-cooperative fashion is often referred to as “temperature 1 self-assembly” or simply “non-cooperative self-assembly”. In this type of self-assembly, a tile may non-cooperatively bind to an assembly via (at least) one of its sides, unlike in cooperative self-assembly, in which some tiles may be required to bind on two or more sides. Cooperative self-assembly leads to highly non-trivial theoretical behavior but two-dimensional non-cooperative self-assembly is conjectured to be only capable of producing highly-regular shapes and patterns, which, in general, cannot be interpreted as complex computation. Remarkably, Cook et al. (Temperature 1 self-assembly: deterministic assembly in 3D and probabilistic assembly in 2D. In: Proceedings of the 22nd Annual ACM–SIAM Symposium on Discrete Algorithms 2011) showed that three-dimensional non-cooperative self-assembly is essentially as powerful as cooperative self-assembly, with respect to Turing universality and self-assembly of \(N \times N\) squares. In this paper, we consider the non-cooperative self-assembly of just-barely 3D shapes. Working in a three-dimensional variant of Winfree’s abstract Tile Assembly Model, we show that, for an arbitrary finite, connected shape \(X \subset {\mathbb {Z}}^2\) , there is a tile set that uniquely self-assembles at temperature 1 into a 3D representation of a scaled-up version of X with optimal program-size complexity, where the “program-size complexity”, also known as “tile complexity”, of a shape is the minimum number of tile types required to uniquely self-assemble it. Moreover, our construction is “just barely” 3D in the sense that it only places tiles in the \(z = 0\) and \(z = 1\) planes. Our result is essentially a just-barely 3D temperature 1 simulation of a similar 2D temperature 2 result by Soloveichik and Winfree (SIAM J Comput 36(6):1544–1569, 2007).
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-016-0260-6
      Issue No: Vol. 80, No. 6 (2018)
       
  • Trees, Paths, Stars, Caterpillars and Spiders
    • Authors: Minghui Jiang
      Pages: 1964 - 1982
      Abstract: For any \(k \ge 2\) , deciding whether the linear arboricity, star arboricity, caterpillar arboricity, spider arboricity, track number, unit track number, and subchromatic index, respectively, of a bipartite graph are at most k are all NP-complete.
      PubDate: 2018-06-01
      DOI: 10.1007/s00453-016-0237-5
      Issue No: Vol. 80, No. 6 (2018)
       
  • Editorial: Special Issue on Computing and Combinatorics
    • Authors: Donglei Du; Dachuan Xu
      PubDate: 2018-02-26
      DOI: 10.1007/s00453-018-0422-9
       
 
 
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