Adaptive linear list reorganization under a generalized query system

1995 ◽  
Vol 32 (03) ◽  
pp. 793-804 ◽  
Author(s):  
R. S. Valiveti ◽  
B. J. Oommen ◽  
J. R. Zgierski
Keyword(s):  
Simple Model ◽  
Query Processing ◽  
Generation Mechanism ◽  
Linear List ◽  
Query Generation ◽  
Query System ◽  
The Individual

We consider the problem of reorganizing a linear list, when the individual queries consist of accesses to a subset of the elements stored, as opposed to the individual elements themselves. In this paper, which to our knowledge represents the first reported result in this model of query processing, we first propose a simple model for a query generator which emits set queries. Subsequently, we present extensions to the classical move-to-front (MTF) and transposition (TR) rules under this generalized query generation mechanism and analyze their performance.

Adaptive linear list reorganization under a generalized query system

1995 ◽  
Vol 32 (3) ◽  
pp. 793-804 ◽  
Author(s):  
R. S. Valiveti ◽  
B. J. Oommen ◽  
J. R. Zgierski
Keyword(s):  
Simple Model ◽  
Query Processing ◽  
Generation Mechanism ◽  
Linear List ◽  
Query Generation ◽  
Query System ◽  
The Individual

We consider the problem of reorganizing a linear list, when the individual queries consist of accesses to a subset of the elements stored, as opposed to the individual elements themselves. In this paper, which to our knowledge represents the first reported result in this model of query processing, we first propose a simple model for a query generator which emits set queries. Subsequently, we present extensions to the classical move-to-front (MTF) and transposition (TR) rules under this generalized query generation mechanism and analyze their performance.

QUERY EVALUATION IN PARTITIONED DISJUNCTIVE DEDUCTIVE DATABASES

1994 ◽  
Vol 03 (04) ◽  
pp. 385-413 ◽  
Author(s):  
ADNAN YAHYA ◽  
JACK MINKER
Keyword(s):  
Query Processing ◽  
Evaluation Process ◽  
Deductive Databases ◽  
Deductive Database ◽  
Query Evaluation ◽  
Disjunctive Deductive Databases ◽  
Special Cases ◽  
The Individual

Query evaluation in disjunctive deductive databases is in general computationally hard. The class of databases for which the process is tractable is severely limited. The complexity of the process depends on the structure of the database as well as on the type of query being evaluated. In this paper we study the issue of simplified query processing in disjunctive deductive databases. We address the possibility of evaluating general queries by independently processing their atomic components and describe the class of databases for which this approach is possible. We also discuss the issue of dividing a disjunctive deductive database into a set of disjoint components then answering queries and computing database completions by combining the results obtained against the individual components. Some practical special cases are considered. The methods developed in this paper can be utilized to introduce parallelism into the query evaluation process.

Loosely-Specified Query Processing in Large-Scale Information Systems

1997 ◽  
Vol 06 (03n04) ◽  
pp. 241-268 ◽  
Author(s):  
Anisoara Nica ◽  
Elke A. Rundensteiner
Keyword(s):  
Query Processing ◽  
Information Integration ◽  
Digital Libraries ◽  
Large Scale ◽  
Information Sources ◽  
Planning Process ◽  
Search Space ◽  
Integration Model ◽  
The Individual ◽  
Query Planning

Challenging issues for processing queries specified over large-scale information spaces (for example, Digital Libraries or the World Wide Web) include the diversity of the information sources in terms of their structures, query interfaces and search capabilities, as well as the dynamics of sources continuously being added, removed or upgraded. In this paper, we give an innovative solution for query planning in such environments. The foundation of our solution is the Dynamic Information Integration Model (DIIM) which supports the specification of not only content but also capabilities of resources without requiring the establishment of a uniform integration schema. Besides the development of the DIIM model, contributions of this paper include: (1) the introduction of the notion of fully specified queries that are semantically equivalent to a loosely-specified query; (2) a translation algorithm of a loosely-specified query into a set of semantically equivalent feasible query plans that are consistent with the binding patterns of query templates of the individual sources (capability descriptions in DIIM) and with interrelationships between information sources (expressed as join constraints in DIIM); and (3) a search restriction algorithm for optimizing query processing by pruning the search space into the relevant subspace of a query. The plans obtained by the proposed query planning process which is composed of the search restriction and translation algorithms can be shown to correspond to query plans semantically equivalent to the initial loosely-specified input query.

Effects of hypoxia and hypercapnia on whole body release and clearance of choline

1995 ◽  
Vol 268 (6) ◽  
pp. R1520-R1525 ◽  
Author(s):  
D. J. Jenden ◽  
O. U. Scremin
Keyword(s):  
Simple Model ◽  
Intravenous Infusion ◽  
Respiratory Acidosis ◽  
Whole Body ◽  
Body Balance ◽  
Arterial Blood ◽  
Individual Contributions ◽  
Per Se ◽  
The Individual

We have recently demonstrated an increase in arterial blood choline (Ch) concentration in normocapnic hypoxia and apnea. This could be due to enhanced release of free Ch from tissues, to decreased Ch clearance, or both. The present investigations was undertaken to determine the individual contributions of these processes to the whole body balance of Ch, using an intravenous infusion of tracer quantities of [2H4]Ch to assess the bidirectional flux between the central pool and peripheral pools. Rats were subjected to normocapnic hypoxia or hypercapnia; release and clearance of Ch were calculated using a simple model. Hypoxia caused an increase in Ch production and a decrease in Ch clearance. At severe levels of hypoxia, Ch clearance was essentially zero. Hypoxia was attended by progressive acidosis that was related to the magnitude of the hypoxic challenge. To determine the possible effects of acidosis per se on the variables measured, respiratory acidosis with normoxia was provoked by controlled administration of CO2. Under these conditions, parallel decreases in Ch production and Ch clearance were observed.

scholarly journals Small-Scale Spatial Gradients in Climatological Precipitation on the Olympic Peninsula

2007 ◽  
Vol 8 (5) ◽  
pp. 1068-1081 ◽  
Author(s):  
Alison M. Anders ◽  
Gerard H. Roe ◽  
Dale R. Durran ◽  
Justin R. Minder
Keyword(s):  
Simple Model ◽  
Mesoscale Model ◽  
Windward Side ◽  
Small Scale ◽  
Precipitation Pattern ◽  
State University ◽  
Spatial Gradients ◽  
The Individual ◽  
High Topography ◽  
The Impact

Abstract Persistent, 10-km-scale gradients in climatological precipitation tied to topography are documented with a finescale rain and snow gauge network in the Matheny Ridge area of the Olympic Mountains of Washington State. Precipitation totals are 50% higher on top of an ∼800-m-high ridge relative to valleys on either side, 10 km distant. Operational fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) runs on a 4-km grid produce similar precipitation patterns with enhanced precipitation over high topography for 6 water years. The performance of the MM5 is compared to the gauge data for 3 wet seasons and for 10 large precipitation events. The cumulative MM5 precipitation forecasts for all seasons and for the sum of all 10 large events compare well with the precipitation measured by the gauges, although some of the individual events are significantly over- or underforecast. This suggests that the MM5 is reproducing the precipitation climatology in the vicinity of the gauges, but that errors for individual events may arise due to inaccurate specification of the incident flow. A computationally simple model of orographic precipitation is shown to reproduce the major features of the event precipitation pattern on the windward side of the range. This simple model can be coupled to landscape evolution models to examine the impact of long-term spatial variability in precipitation on the evolution of topography over thousands to millions of years.

scholarly journals Self-Organization When Pedestrians Move in Opposite Directions. Multi-Lane Circular Track Model

2020 ◽  
Vol 10 (2) ◽  
pp. 563 ◽  
Author(s):  
Guillermo H. Goldsztein
Keyword(s):  
Simple Model ◽  
Opposite Direction ◽  
Self Organization ◽  
Circular Track ◽  
The Individual

When pedestrians walk along a corridor in both directions, a frequently observed phenomenon is the segregation of the whole group into lanes of individuals moving in the same direction. While this formation of lanes facilitates the flow and benefits the whole group, it is believed that results from the actions of the individuals acting on their behalf, without considering others. This phenomenon is an example of self-organization and has attracted the attention of a number of researchers in diverse fields. We introduce and analyze a simple model. We assume that individuals move around a multi-lane circular track. All of them move at the same speed. Half of them in one direction and the rest in the opposite direction. Each time two individuals collide, one of them moves to a neighboring lane. The individual changing lanes is selected randomly. We prove that the system self-organizes. Eventually, each lane is occupied with individuals moving in only one direction. Our analysis supports the belief that global self-organization is possible even if each member of the group acts without considering the rest.

scholarly journals A model for the emergence of pillars, walls and royal chambers in termite nests

1998 ◽  
Vol 353 (1375) ◽  
pp. 1561-1576 ◽  
Author(s):  
E. Bonabeau ◽  
G. Theraulaz ◽  
J. Deneubourg ◽  
N. R. Franks ◽  
O. Rafelsberger ◽  
...  
Keyword(s):  
Simple Model ◽  
Original Model ◽  
Building Conditions ◽  
Morphogenetic Process ◽  
Individual Level ◽  
Air Stream ◽  
Specific Direction ◽  
Net Flux ◽  
The Individual ◽  
Pheromone Trail

A simple model of the emergence of pillars in termite nests by Deneubourg is modified to include several additional features that break the homogeneity of the original model: (i) a convection air stream that drives molecules of pheromone along a given direction; (ii) a net flux of individuals in a specific direction; (iii) a well–defined self–maintained pheromone trail; and (iv) a pheromonal template representing the effect of the presence of a queen that continuously emits pheromone. It is shown that, under certain conditions, pillars are transformed into walls or galleries or chambers, and that this transformation may not be driven by any change in the termites' behaviour. Because the same type of response at the individual level can generate different patterns under different conditions, and because previous construction modifies current building conditions, we hypothesize that nest complexity can result from the unfolding of a morphogenetic process that progressively generates a diversity of history–dependent structures.

Concept and validation of a simple model of the intrathyroidal iodine kinetics

2004 ◽  
Vol 43 (01) ◽  
pp. 21-25 ◽  
Author(s):  
F.-J. Bormuth ◽  
S. Braun ◽  
M. Zimny ◽  
H.-J. Schroth ◽  
Th. Rink
Keyword(s):  
Simple Model ◽  
Radioiodine Therapy ◽  
Iodine Content ◽  
Iodine Intake ◽  
Iodine Uptake ◽  
Average Deviation ◽  
Regression Curves ◽  
Significant Difference ◽  
Iodine Excretion ◽  
The Individual

Summary Aim of this study is the introduction and validation of a simple model of the intrathyroidal iodine kinetics, designed for optimizing radioiodine therapy planning and dose measurement in a routine clinical setting. Methods: The new model defines the intrathyroidal iodine kinetics as balance of the thyroidal iodine intake and -excretion, characterized by the two exponential equations At = A0 * (1-exp(-λ1t)) and At = A0 * (exp(-λ2t) -1), respectively. A0 describes the theoretically maximum iodine uptake when the thyroidal iodine excretion is ignored, λ1 and λ2 represent the constants characterizing the iodine intake and excretion, respectively. The thyroidal iodine content at the time t equals the sum of both functions, which is At = A0 * (exp(-λ2t)-exp(-λ1t)). In 25 patients with autonomous goiter / nodules (n = 18), Graves’ disease (n = 5), or endemic euthyroid goiter (n = 2), the iodine uptake in the thyroid during the radioiodine therapy as fraction of the applied activity was determined daily, with the remaining body covered by a lead shield. On average, 7.2 measurements were performed per patient (minimum 4, maximum 13). With these uptake values, individual regression curves were fitted using the above equation, and the difference between the actual measurements and the corresponding values of the regression curves was determined. Results: The average deviation of the 179 uptake values from the calculated points of the respective regression curves was only 1.4%. There was no significant difference between the three disease groups. The distribution of the relative deviations during the individual courses was constant, systematic errors were not detected. Conclusion: Our results suggest that the intrathyroidal iodine kinetics can be precisely described with the model At = A0 * (exp(-λ2t)-exp(-λ1t)). With only three measurements, the trend of the curve can be calculated, which allows to determine the total radioiodine storage in the thyroid.

scholarly journals The Mode-Separated Pulse Profiles of Pulsar Radio Emission

2000 ◽  
Vol 177 ◽  
pp. 261-264
Author(s):  
Mark M. McKinnon ◽  
Daniel R. Stinebring
Keyword(s):  
Simple Model ◽  
Radio Emission ◽  
Orthogonal Polarization ◽  
Pulse Profile ◽  
Pulsar Radio ◽  
Linearly Polarized ◽  
The Individual ◽  
Pulsar Radio Emission

AbstractTwo modes of orthogonal polarization are generally observed in the radio emission from pulsars. Essentially all attempts to calculate the average profiles of the individual modes have assumed that the modes occur separately. We have presented evidence, however, that the modes occur simultaneously. Therefore, we believe that “mode-separated” pulse profiles which have been published to date reveal little about the polarization properties of the individual modes.Calculating mode-separated pulse profiles for superposed orthogonal modes is complicated by the unknown polarization properties of the individual modes. However, the simplest model of pulsar radio emission which can explain the wide variety in the emission’s polarization is one in which the individual modes are completely polarized. We use our simple model to compute the average profiles of the orthogonal modes in PSR B0525+21. The total intensity of the two mode profiles resembles the overall pulse profile, and each profile is highly linearly polarized.

Sign in / Sign up

Export Citation Format

Share Document