Simple Predicates Research Articles

On the complexity of XPath containment in the presence of disjunction, DTDs, and variables

XPath is a simple language for navigating an XML-tree and returning a set of answer nodes. The focus in this paper is on the complexity of the containment problem for various fragments of XPath. We restrict attention to the most common XPath expressions which navigate along the child and/or descendant axis. In addition to basic expressions using only node tests and simple predicates, we also consider disjunction and variables (ranging over nodes). Further, we investigate the containment problem relative to a given DTD. With respect to variables we study two semantics, (1) the original semantics of XPath, where the values of variables are given by an outer context, and (2) an existential semantics introduced by Deutsch and Tannen, in which the values of variables are existentially quantified. In this framework, we establish an exact classification of the complexity of the containment problem for many XPath fragments.

Précis of Beyond Rigidity

Beyond Rigidity is divided into two parts. Part 1 is devoted to the semantics and pragmatics of names, and the sentences, including attitude ascriptions, that contain them. In part 2, the model developed in part 1 is extended to natural kind terms, and simple predicates in which they occur. The model is then used to explain the necessity of certain aposteriori statements containing such predicates. Part 1 begins with a review of Kripke's arguments against traditional descriptive semantic analyses of proper names. Special attention is paid to the modal argument, which is strengthened to rule out analyses that treat names as synonymous with rigidified descriptions, or descriptions that are required to take wide scope when embedded under modal operators or predicates. I then try to fill an important gap in Kripke's original story by providing a positive account of the meaning and semantic content of names. The central question is What do proper names contribute to the semantic contents of (i.e. the propositions semantically expressed by) sentences that contain them? The answer developed divides names into two classes, linguistically simple like Pedro Martinez, Microsoft, and Seattle and partially descriptive like Mrs. Thatcher, Queen Elizabeth, Princeton University, Yankee Stadium, and Mt. Washington. Linguistically simple names are purely Millian; their meanings (semantic contents) are their referents, and the semantic contents of sentences containing them are singular, Russellian propositions. By contrast, the semantic contents of partially descriptive names are complexes consisting of their referents, plus properties predicated of the referents. For

Security Vulnerabilities: From Analysis to Detection and Masking Techniques

This paper presents a study that uses extensive analysis of real security vulnerabilities to drive the development of: 1) runtime techniques for detection/masking of security attacks and 2) formal source code analysis methods to enable identification and removal of potential security vulnerabilities. A finite-state machine (FSM) approach is employed to decompose programs into multiple elementary activities, making it possible to extract simple predicates to be ensured for security. The FSM analysis pinpoints common characteristics among a broad range of security vulnerabilities: predictable memory layout, unprotected control data, and pointer taintedness. We propose memory layout randomization and control data randomization to mask the vulnerabilities at runtime. We also propose a static analysis approach to detect potential security vulnerabilities using the notion of pointer taintedness.

Entropy Based Evaluation of Communication Predictability in Parallel Applications

The performance of parallel computing applications is highly dependent on the efficiency of the underlying communication operations. While often characterized as dynamic, these communication operations frequently exhibit spatial and temporal locality as well as regularity in structure. These characteristics can be exploited to improve communication performance if the correct prediction model is selected to a suitable communication topology. In this paper we describe an entropy based methodology for quantifying and evaluating the success of different prediction models on actual workloads drawn from representative parallel benchmarks. We evaluate two different prediction criteria and combinations thereof: (1) Messages are partitioned by source node. (2) Use of a first order context model. We also describe the threshold for predication designed to largely avoid incorrect predication overheads. Our results show for simple predication models, even on highly dynamic benchmark applications, predictability can be improved by several orders of magnitude. In fact, using simple prediction techniques, over 75% of the communication volume is accurately predictable.

Les réseaux de Petri pour le contrôle des systèmes à événements discrets

In this thesis, we propose two control synthesis methods for discrete event systems (DES) modeled by Petri nets (PN) and having some uncontrollable transitions. The first approach allows to design a PN model of the controlled system by adding a set of control places to an original PN. The controlled model has to achieve a desired behavior corresponding to the so-called forbidden state transition problem (FSTP). The controller designed by this approach is maximally permissive. Further desired behaviors that can't be realized by PN based controller are well characterized. The second control synthesis approach we propose in this thesis addresses the particular case of forbidden state problem of marked graphs. The control decision can be taken on-line by evaluating simple predicates at each current marking.

LEO: An autonomic query optimizer for DB2

SQL has emerged as an industry standard for querying relational database management systems, largely because a user need only specify what data is wanted, not the details of how to access that data. A query optimizer uses a mathematical model of query execution to determine automatically the best way to access and process any given SQL query. This model is heavily dependent upon the optimizer's estimates for the number of rows that will result at each step of the query execution plan (QEP), especially for complex queries involving many predicates and/or operations. These estimates rely upon statistics on the database and modeling assumptions that may or may not be true for a given database. In this paper we discuss an autonomic query optimizer that automatically self-validates its model without requiring any user interaction to repair incorrect statistics or cardinality estimates. By monitoring queries as they execute, the autonomic optimizer compares the optimizer's estimates with actuals at each step in a QEP, and computes adjustments to its estimates that may be used during future optimizations of similar queries. Moreover, estimation errors can also trigger re-optimization of a query in mid-execution. The autonomic refinement of the optimizer's model can result in a reduction of query execution time by orders of magnitude at negligible additional run-time cost. We discuss various research issues and practical considerations that we needed to address during our implementation of a first prototype of LEO, a LEarning Optimizer for DB2® (Database 2™)that learns table access cardinalities and for future queries corrects the estimation error for simple predicates by adjusting the database statistics of DB2.

An elementary algorithm for reporting intersections of red/blue curve segments

Let E r and E b be two sets of x-monotone and non-intersecting curve segments, E= E r∪ E b and | E|= n. We give a new sweep-line algorithm that reports the k intersecting pairs of segments of E. Our algorithm uses only three simple predicates that allow to decide if two segments intersect, if a point is left or right to another point, and if a point is above, below or on a segment. These three predicates seem to be the simplest predicates that lead to subquadratic algorithms. Our algorithm is almost optimal in this restricted model of computation. Its time complexity is O( nlog n+ kloglog n) and it requires O( n) space.

Plural Predication and the Strongest Meaning Hypothesis

The Strongest Meaning Hypothesis of Dalrymple et al. (1994, 1998), which was originally proposed as a principle for the interpretation of reciprocals, is extended in this paper into a general principle of plural predication. This principle applies to complex predicates that are composed of lexical predicates that hold of atomic entities, and determines the pluralities in the extension of the predicate. The meaning of such a complex predicate is claimed to be the truth‐conditionally strongest meaning that does not contradict lexical properties of the simple predicates it contains. Weak interpretations of reciprocals (as in the books are stacked on top of each other), plural predicate conjunction (e.g. the books are old and new) and ‘atomic’ distributivity in general are derived by a unified mechanism, which ‘weakens’ the basic universal meanings of strong reciprocals, boolean conjunction and quantification over atomic entities.

Vers une structuration de dictionnaires servant à la Tao

We have investigated the contrastive French-German aspects of about 50 simple nominal and compound adjectival predicates, and designed their entries for an electronic dictionary for computer-assisted translation. Their co-occurrence with support verbs expressing different aspectual semantic functions is coded; in the case of the nouns, their co-occurrence with determiners is also coded, as is the syntactic and semantic specification of their arguments in terms of semantic classes called “object classes”. As an illustration of the envisaged translation methodology based on lexicon-grammar, the syntactic tagging of different formal types of simple and compound predicates, and the semantic tagging of their arguments, are demonstrated with reference to a German newspaper text and its French translation. intex will be used not only for identifying and translating compound words or multi-word expressions, but also — as an additional, but necessary tool — for finding object classes together with their appropriate predicates and support verbs, because object classes are clearly syntactically defined.

An Integrated Account of Theistic Predication

Simple predications consist of three elements: a singular term, a predicate term, and a copula (characteristically but not necessarily a form of the verb be). According to an intensional interpretation, the meaning of a singular term, be it a proper name or a definite description, is identifiable with the concept it conveys. The meaning of a predicate term is associated with the property it expresses. When a predicate term is conjoined with a singular term, perhaps by some variety of the verb be, a sentence is formed that can assert a proposition capable of truth or falsity. Aristotle presented the first systematic account of simple predications in his De Interpretatione (16a-18a). He analyzed examples such as is and Man is just. The former exemplifies simple predication: the property of being white is affirmed to inhere in the individual human being Socrates. The latter does not strictly count as a simple predication because it is analyzable as Every man is just--a sentence whose subject term is modified by a plural quantifier. Aristotle interpreted terms in the fashion defined above, but almost interchangeably gave extensional readings to the effect that singular terms designate individual objects and predicate terms denote classes of objects. A simple predication interpreted in this way says that the individual designated by the subject term is a member of the class denoted by the predicate term: Socrates is a member of the class of white things. Stoic logicians clarified the distinction between intensional and extensional interpretations in their celebrated trichotomy of sign, sense, and thing signified (Sextus Empiricus, Adversus Mathematicos 8.11-12). Formal logic in the West has proceeded primarily with the use of the latter, more materialist point of view. Here intensional meanings will provide the logical starting point for reflection, appropriately so since the language of special concern deals with the purportedly immaterial being of God. Thus far discussion has featured standard elements of logical theory. I introduce some novel terminology by saying that simple predications may be either mediated or unmediated. When they are unmediated, the meanings of constituent terms are unambiguous, the truth conditions of propositions are determinate, and the distinction between signs and things signified is consistently maintained. Unmediated predications belong to the domain of logical semantics and satisfy a computational requirement of being reduced to a formal symbolism that can be manipulated by a machine as well as by a human mind. In a strict sense, the criteria for unmediated predications are met only in a restricted set of languages extensionally interpreted, yet they remain a regulatory ideal for logicians working with richer formal languages.' They do not serve similarly for dialectical logicians like Hegel (soon to be discussed), nor are they the primary desiderata for people speaking about God. Key examples will clarify the distinction. Mediated predications traverse at least one criterion of unmediated predications and really belong to the domain of phenomenological semantics. Mediation in this context connotes a mental process that reflectively relates logical matters (e.g., terms, truth conditions, and so forth) to intuitions about priority, temporality, and intentionality. Mediated predications are mediated by human reflection in a way that renders them no longer appropriate for purely mechanical computation. By intentionality, I mean the directedness of consciousness toward some mental object which may or may not actually exist. Language is a major means for directing human consciousness toward mental objects and the intentionality of linguistic meaning is relevant to the main thesis of this essay for two reasons. First, as Edmund Husserl showed in his example of the God Jupiter in the Logical Investigations (5.2.11), it provides a way of ascribing meaning to talk about things that do not materially exist. …

Query optimization and execution plan generation in object-oriented data management systems

The generation of execution plans for object-oriented database queries is a new and challenging area of study. Unlike relational algebra, a common set of object algebra operators has not been defined. Similarly, a standardized object manager interface analogous to the storage manager interface of relational subsystems does not exist. We define the interface to an object manager whose operations are the executable elements of query execution plans. Parameters to the object manager interface are streams of tuples of object identifiers. The object manager can apply methods and simple predicates to the objects identified in a tuple. Two algorithms for generating such execution plans for queries expressed in an object algebra are presented. The first algorithm runs quickly but may produce inefficient plans. The second algorithm enumerates all possible execution plans and presents them in an efficient, compact representation. >

Nominal comparatives and Generalized Quantifiers

This work adopts the perspective of plural logic and measurement theory in order first to focus on the microstructure of comparative determiners; and second, to derive the properties of comparative determiners as these are studied in Generalized Quantifier Theory, locus of the most sophisticated semantic analysis of natural language determiners. The work here appears to be the first to examine comparatives within plural logic, a step which appears necessary, but which also harbors specific analytical problems examined here. Since nominal comparatives involve plural and mass reference, we begin with a domain of discourse upon which a lattice structure (Link's) is imposed, and which maps (via abstract dimensions such asweight in kilograms) to concrete measures (in N,R+). The mapping must be homomorphic and Archimedean. Comparisons begin as simple predicates on dimensions or measures; from these we derive classes of predicates on the domain, i.e., generalized determiners (quantifiers), and show, e.g., how monotonicity properties follow in the derivation. This results in a proposal for a logical language which includes derived determiners, and which is an attractive target for semantics interpretation; it also turns out that some interesting comparative determiners are first order, at least when restricted to nonparametric and noncollective predications.

A conceptual clustering algorithm for database schema design

Conceptual clustering techniques based on current theories of categorization provide a way to design database schemas that more accurately represent classes. An approach is presented in which classes are treated as complex clusters of concepts rather than as simple predicates. An important service provided by the database is determining whether a particular instance is a member of a class. A conceptual clustering algorithm based on theories of categorization aids in building classes by grouping related instances and developing class descriptions. The resulting database schema addresses a number of properties of categories, including default values and prototypes, analogical reasoning, exception handling, and family resemblance. Class cohesion results from trying to resolve conflicts between building generalized class descriptions and accommodating members of the class that deviate from these descriptions. This is achieved by combining techniques from machine learning, specifically explanation-based learning and case-based reasoning. A subsumption function is used to compare two class descriptions. A realization function is used to determine whether an instance meets an existing class description. A new function, INTERSECT, is introduced to compare the similarity of two instances. INTERSECT is used in defining an exception condition. Exception handling results in schema modification. This approach is applied to the database problems of schema integration, schema generation, query processing, and view creation. >

The term retrieval abstract machine

Scans through large collections of complex objects often cannot be avoided. Even if sohphisticated indexing mechanisms are provided, it may be necessary to evaluate simple predicates against data stored on disk for filtering. For traditional record oriented data models i/o and buffer management are the main bottlenecks for this operation, the interpretation of data structures is straightforward and usually not an important cost factor. For heterogeneously shaped complex objects it may become a dominant cost factor. In this paper we demonstrate a technique to make data structure traversal inside of complex objects much cheaper than naive interpretation. We compile navigation necessary to evaluate condition predicates and physical schema information into a program to be executed by a specialized abstract machine. Our approach is demonstrated for the Feature Term Data Model (FTDM), but the technique is applicable to many other complex data models. Main parts of this paper are dedicated to the method we used to design the Term Retrieval Abstract Machine (TRAM) architecture by partial evaluation of a tuned interpreter.

Causation, Supervenience, and Method. Reflections on Jonathan Bennett's Events and Their Names

This vastly learned, instructive, and entertaining book is full of good things. Some are cameo gems, such as the plea to treat identity not relationally but through simple predication, and the decision, following Locke and Donald Williams, to treat the term 'abstract' as the antonym of 'concrete', carrying no implications of extra-spatio-temporality or causal nullity. Others are more substantial achievements, such as the successful negative treatment of events as Quinean concrete totalities, and the extended discussion of the 'by' locution. Nevertheless, it seems to me that there is a deep disharmony between various key theses of the book, which can be fitted to one another with difficulty if at all. Facts are to be distinguished from events. The distinction is not total, for facts and events both belong to the same category, that of tropes. But facts are more fine-grained. The fact that Peter swam to Calais is a different fact from the fact that he journeyed there. But there are not two superimposed events, Peter's swim and Peter's journey. The journey is the swim. The swim is the journey. Events are tropes which can have an extensive nature undisclosed by the description through which we pick them out.. But with facts you see is what you get. The full identifying character of a fact is presented by the fact-stating sentence from which its nominal derives. Now this distinction within the, category of tropes is not in itself a source of any difficulty. But troubles arise when we explore what tropes are held to be, and what causal role is claimed for them. Bennett has two working definitions of a trope: a trope is an instance of a property. At p. 15, the paradigm is the whiteness of my house, and the property is exemplified by a substance (the house). At p. 88 it is always a spacetime zone which instantiates a property and thus constitutes a trope. So the

Albert the Great on the Semantics of the Categories of Substance, Quantity, and Quality

Summary The underlying theory for modistic grammar is Aristotelian metaphysics, especially the theory of the categories. This paper deals with the semantics of the categories as viewed by one of the most important medieval commentators, Albert the Great. Albert’s comments on the categories of substance, quantity, and quality are considered, and the relation of these to the other seven categories is also discussed. The categories are modes of predicating with respect to what the predicates signify. Substance words are predicated univocally while terms signifying accidents are predicated paronymously. Secondary substance signifies quale quid; hence common nouns are names of kinds. Primary substance signifies hoc aliquid, the concrete individual; for this reason proper nouns are grammatical subjects but not genuine predicates. Quantity and quality are simple and absolute modes or predication. They are intrinsic accidents because they are based on the matter-form composition of substance. An interesting aspect of the Aristotelian conception of quantity is the view that speech is a discrete quantity. Quality words signify quale rather than quale quid; hence the distinction between sortal and characterizing predicates is a basic idea of Aristotelian ontology. As for the other categories, relation is a simple but not an absolute mode of predication. The other six categories all express some mode of relatedness and thus are regarded as extrinsic principles of being.

Son of Grue: Simplicity vs. Entrenchment

The purpose of this paper is to reconsider the new riddle of induction, to argue against entrenchment1 as an explanation of projectibility,2 and to argue that terms like 'grue'3 can be shown to be illegitimate in scientific discourse because they are less simple than corresponding terms like 'green'. First, I believe entrenchment is inadequate as an explanation of projectibility, not only because it is too weak, but also because of certain counterexamples in which the projectibility of predicates varies independently of their entrenchment. Second, I believe that projectibility can be explained in terms of simplicity. Now this is nothing new. Several articles have explicitly tried to explain projectibility in terms of simplicity ([2], [4]).4 Moreover, simplicity seems to have been a principal methodological motivation even in most of those articles that do not appeal to it directly ([1], [9], [11], [13], [15], [16], [17]). The problem with all these approaches, however, is that they do not provide a theory of simplicity which is both sufficiently systematic and also successful over a broad range to function as a regulative methodological principle. I believe I have offered such a theory in [3] and will apply it to show that 'green' is simpler than 'grue'. Third, despite the counterexamples of the first part, entrenchment does generally vary with projectibility. It is the job of an account of projectibility to explain why entrenchment works where it does and why it does not work where it doesn't. This can be done, although it requires certain weak psychological assumptions about tendencies to adopt simple predicates. Along these lines, I want to refute a claim of Goodman ([5], [6]) that considerations of entrenchment explain our intuitions of simplicity. Prima facie, this is not an unreasonable view, particularly if there is no theory of simplicity to account for these intuitions. However, I will argue that the theory