Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

/pdf/convex-analysisnoer-san-nojin-zhan-nituite-5dl2rbmoyr.pdf

Convex Analysisの二,三の進展について

Data integration is the problem of combining data residing at different sources, and providing the user with a unified view of these data. The problem of designing data integration systems is important in current real world applications, and is characterized by a number of issues that are interesting from a theoretical point of view. This document presents on overview of the material to be presented in a tutorial on data integration. The tutorial is focused on some of the theoretical issues that are relevant for data integration. Special attention will be devoted to the following aspects: modeling a data integration application, processing queries in data integration, dealing with inconsistent data sources, and reasoning on queries.

/pdf/data-integration-a-theoretical-perspective-58aesjvhuk.pdf

Data integration: a theoretical perspective

Optimization, approximation, and complexity classes

Schema mappings are high-level specifications that describe the relationship between two database schemas. They are considered to be the essential building blocks in data exchange and data integration, and have been the focus of extensive research investigations. Since in real-life applications schema mappings can be quite complex, it is important to develop methods and tools for illustrating, explaining, and deriving schema mappings. A promising approach to this effect is to use "good" data examples that illustrate the schema mapping at hand.In this talk, we present an overview of recent work on characterizing schema mappings via a finite set of data examples. We show that every LAV schema mapping (i.e., a schema mapping specified by a finite set of local-as-view tuple-generating dependencies) is uniquely characterized by a finite set of universal data examples with respect to the class of all LAV schema mappings. We also show that this type of result does not hold for arbitrary GAV schema mappings (i.e., schema mappings specified by a finite set of global-as-view tuple-generating dependencies). After this, we give a necessary and sufficient condition for a GAV schema mapping to be uniquely characterizable by a finite set of universal examples with respect to the class of all GAV schema mappings. Along the way, we establish tight connections between unique characterizability of schema mappings, Armstrong databases, and homomorphism dualities.

https://openproceedings.org/2013/conf/edbt/CateKT13.pdf

Schema mappings and data examples

Querying semi-structured data.- Information integration using logical views.- Methods and problems in data mining.- Conjunctive query containment revisited.- Semantics and containment of queries with internal and external conjunctions.- Efficient complete local tests for conjunctive query constraints with negation.- Selection of views to materialize in a data warehouse.- Total and partial well-founded Datalog coincide.- Fine hierarchies of generic computation.- Local properties of query languages.- Expressiveness and complexity of active databases.- A model theoretic approach to update rule programs.- Abstract interpretation of active rules and its use in termination analysis.- Structural issues in active rule systems.- Discovering all most specific sentences by randomized algorithms extended abstract.- A formal foundation for distributed workflow execution based on state charts.- Incorporating user preferences in multimedia queries.- Queries and computation on the Web.- The complexity of iterated belief revision.- Expressive power of unary counters.- Concurrency control theory for deferred materialized views.- Serializability of nested transactions in multidatabases.- Adding structure to unstructured data.- Correspondence and translation for heterogeneous data.- Type-consistency problems for queries in object-oriented databases.- Object-oriented database evolution.- Performance of nearest neighbor queries in R-trees.- Optimal allocation of two-dimensional data (Extended abstract).- Efficient indexing for constraint and temporal databases.- On topological elementary equivalence of spatial databases.- Model-theoretic minimal change operators for constraint databases.- Tractable iteration mechanisms for bag languages.

Database theory -- ICDT '97 : 6th International Conference, Delphi, Greece, January 8-10, 1997 : proceedings

We introduce a class of counting problems that arise naturally in equational matching and study their computational complexity. If E is an equational theory, then #E-Matching is the problem of counting the number of complete minimal E-matchers of two given terms. #E-Matching is a well-defined algorithmic problem for every finitary equational theory. Moreover, it captures more accurately the computational difficulties associated with finding complete sets of minimal E-matchers than the corresponding decision problem for E-matching does.

The Complexity of Counting Problems in Equational Matching

How to define a linear order on finite models

The infinitary logic ℒ ω ∞ω consists of all formulas of ℒ∞ω with a finite number of variables. During the past several years, the study of ℒ ω ∞ω has occupied a prominent place in finite model theory. We present an overview of results concerning the interaction of ℒ ω ∞ω with least fixed-point logic and first-order implicit definability on finite structures.

Phokion G. Kolaitis

Papers

Schema mappings and data examples

Database theory -- ICDT '97 : 6th International Conference, Delphi, Greece, January 8-10, 1997 : proceedings

The Complexity of Counting Problems in Equational Matching

How to define a linear order on finite models

Infinitary Logic in Finite Model Theory