Nash equilibrium based semantic cache in mobile sensor grid database systems

Mobile applications are being increasingly deployed on a massive scale in various mobile sensor grid database systems. With limited resources from the mobile devices, how to process the huge number of queries from mobile users with distributed sensor grid databases becomes a critical problem for such mobile systems. While the fundamental semantic cache technique has been investigated for query optimization in sensor grid database systems, the problem is still difficult due to the fact that more realistic multi-dimensional constraints have not been considered in existing methods. To solve the problem, a new semantic cache scheme is presented in this paper for location-dependent data queries in distributed sensor grid database systems. It considers multi-dimensional constraints or factors in a unified cost model architecture, determines the parameters of the cost model in the scheme by using the concept of Nash equilibrium from game theory, and makes semantic cache decisions from the established cost model. The scenarios of three factors of semantic, time and locations are investigated as special cases, which improve existing methods. Experiments are conducted to demonstrate the semantic cache scheme presented in this paper for distributed sensor grid database systems.

Nonuniform random geometric graphs with location-dependent radii

We propose a distribution-free approach to the study of random geometric graphs. The distribution of vertices follows a Poisson point process with intensity function n f(center dot), where n is an element of N, and f is a probability density function on R-d. A vertex located at x connects via directed edges to other vertices that are within a cut-off distance r(n)(x). We prove strong law results for (i) the critical cut-off function so that almost surely, the graph does not contain any node with out-degree zero for sufficiently large n and (ii) the maximum and minimum vertex degrees. We also provide a characterization of the cut-off function for which the number of nodes with out-degree zero converges in distribution to a Poisson random variable. We illustrate this result for a class of densities with compact support that have at most polynomial rates of decay to zero. Finally, we state a sufficient condition for an enhanced version of the above graph to be almost surely connected eventually.

Active Dendrites Regulate Spectral Selectivity in Location-Dependent Spike Initiation Dynamics of Hippocampal Model Neurons

How does the presence of plastic active dendrites in a pyramidal neuron alter its spike initiation dynamics? To answer this question, we measured the spike-triggered average (STA) from experimentally constrained, conductance-based hippocampal neuronal models of various morphological complexities. We transformed the STA computed from these models to the spectral and the spectrotemporal domains and found that the spike initiation dynamics exhibited temporally localized selectivity to a characteristic frequency. In the presence of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, the STA characteristic frequency strongly correlated with the subthreshold resonance frequency in the theta frequency range. Increases in HCN channel density or in input variance increased the STA characteristic frequency and its selectivity strength. In the absence of HCN channels, the STA exhibited weak delta frequency selectivity and the characteristic frequency was related to the repolarization dynamics of the action potentials and the recovery kinetics of sodium channels from inactivation. Comparison of STA obtained with inputs at various dendritic locations revealed that nonspiking and spiking dendrites increased and reduced the spectrotemporal integration window of the STA with increasing distance from the soma as direct consequences of passive filtering and dendritic spike initiation, respectively. Finally, the presence of HCN channels set the STA characteristic frequency in the theta range across the somatodendritic arbor and specific STA measurements were strongly related to equivalent transfer-impedance-related measurements. Our results identify explicit roles for plastic active dendrites in neural coding and strongly recommend a dynamically reconfigurable multi-STA model to characterize location-dependent input feature selectivity in pyramidal neurons.

Stock assessment of Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin) using fishery dependent data from the Tanzanian waters of Lake Victoria

Catch data were collected from three beaches in the Mwanza area of lake Victoria, Tanzania for Oreochromis niloticus (L.), Rastrineobola argentea (Pellegrin) and Lates niloticus (L.). Sampling took place in October 1997 and February, June and September 1998. The CPUE for O. niloticus was 3.9 to 6kg boat super(-1) and for R. argentea from 98 to 282 kg boat super(-1). There was no obvious trend in catch rates for L. niloticus. The modal length for O. niloticus recorded at Chole beach was 34cm TL. In February, fish were larger (41-45 cm) than in the other surveys. Rastrineobola argentea caught in October 1997 had modal length at 65 mm TL with some smaller fish. In February and June prominent length modes occurred at 45 and 58 mm respectively, which may represent the same cohort as the small fish caught in October 1997. In September 1998, there were two length modes at 46 and 60 mm. The 60 mm fish may represent the same cohort seen in previous surveys, suggesting growth from approximately 30 mm to 60 mm in an eleven-month period. Lates niloticus landed at Kayenze beach over the four surveys had a modal length of 46 cm TL. Fish species encountered on the three beaches during the surveys were O. niloticus, R. argentea, Bagrus docmak Forsskall, Clarias gariepinus (Burchell), Protopterus aethiopicus Heckel, Labeo victorians Boulenger, Synodontis afrofischeri Hilgendorf, Synodontis victoriae Boulanger, Schilbe intermedius (L.), Brycinus jacksonii (Boulanger), Mormyrus kannume Forsskall and Haplochromine cichlids

Stock assessment of Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin) using fisheries-dependent data from Tanzania waters of Lake Victoria

Three commercially important fish species, Lates niloticus (L.), Rastrineobola argentea (Pellegrin) and Oreochromis niloticus (L.) that are fished by artisanal fishermen of Lake Victoria, Tanzania part, were studied in Kagera, Mwanza and Mara beaches from October 1997 to July 1999. Catches, effort, exploitation and stock structure were investigated. Beaches for sampling were selected based on importance for landing the above named fish species. The number of boats found on beach that day, the number that lay idle and their means of propulsion were recorded. As many boats as possible were sampled for gear type and gear size. The catches were sorted into species and measured. Variation in the species and size composition of landings was observed between regions, between months and between gears used. The implications of the findings to management are discussed.

基于对象关系的位置相关数据库模型及其移动持续查询处理策略

近年来，人们对位置相关的信息服务进行了较为大量的研究，这些工作主要以移动对象数据库及空间数据库框架为基础，探讨如何有效地支持位置相关的查询等问题．然而，另一类重要的数据类型——位置相关的数据(10cation dependent data，LDD)，却没有得到人们足够的重视．目前，LDD的研究主要集中在概念应用层，缺乏完善的数据库模型(包括数据类型及查询操作等)及有效的查询处理方法．为了解决上述问题，提出一种基于对象关系数据库模型的位置相关数据模型(object—relational database based LDD model，ORLDD)。在ORLDD中，定义了完整的位置相关数据类型及查询操作，给出了相关的移动持续查询处理方法，并阐述了在对象关系数据库系统PostgreSQL上的实现方法．实验结果表明，该方法具有良好的查询处理性能及灵活性．

Fleet dynamics in multispecies trawlers: a study based on fisheries-dependent data

Tese de doutoramento, Ciências do Mar, da Terra e do Ambiente (Avaliação e Gestão de Recursos), Faculdade das Ciências do Mar e do Ambiente, Universidade do Algarve, 2013

Errors due to the tropospheric and ionospheric effects on the geographic location of data collection platforms

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A mixed model QTL analysis for sugarcane multiple-harvest-location trial data

Sugarcane-breeding programs take at least 12 years to develop new commercial cultivars. Molecular markers offer a possibility to study the genetic architecture of quantitative traits in sugarcane, and they may be used in marker-assisted selection to speed up artificial selection. Although the performance of sugarcane progenies in breeding programs are commonly evaluated across a range of locations and harvest years, many of the QTL detection methods ignore two- and three-way interactions between QTL, harvest, and location. In this work, a strategy for QTL detection in multi-harvest-location trial data, based on interval mapping and mixed models, is proposed and applied to map QTL effects on a segregating progeny from a biparental cross of pre-commercial Brazilian cultivars, evaluated at two locations and three consecutive harvest years for cane yield (tonnes per hectare), sugar yield (tonnes per hectare), fiber percent, and sucrose content. In the mixed model, we have included appropriate (co)variance structures for modeling heterogeneity and correlation of genetic effects and non-genetic residual effects. Forty-six QTLs were found: 13 QTLs for cane yield, 14 for sugar yield, 11 for fiber percent, and 8 for sucrose content. In addition, QTL by harvest, QTL by location, and QTL by harvest by location interaction effects were significant for all evaluated traits (30 QTLs showed some interaction, and 16 none). Our results contribute to a better understanding of the genetic architecture of complex traits related to biomass production and sucrose content in sugarcane.

CERCLIS (Comprehensive environmental response, compensation, and liability information system) site location extract data element dictionary.

PB90-215120

Spatial-temporal mining of archived automatic vehicle location (AVL) data for transit service planning applications

An Automatic Vehicle Location (AVL) system is a computer-based vehicle tracking system that is capable of determining a vehicle's location in real time. As a major technology of the Advanced Public Transportation System (APTS), AVL systems have been widely deployed by transit agencies for purposes such as real-time operation monitoring, computer-aided dispatching, and arrival time prediction. AVL systems make a large amount of transit performance data available that are valuable for transit performance management and planning purposes. However, the difficulties of extracting useful information from the huge spatial-temporal database have hindered off-line applications of the AVL data. ^ In this study, a data mining process, including data integration, cluster analysis, and multiple regression, is proposed. The AVL-generated data are first integrated into a Geographic Information System (GIS) platform. The model-based cluster method is employed to investigate the spatial and temporal patterns of transit travel speeds, which may be easily translated into travel time. The transit speed variations along the route segments are identified. Transit service periods such as morning peak, mid-day, afternoon peak, and evening periods are determined based on analyses of transit travel speed variations for different times of day. The seasonal patterns of transit performance are investigated by using the analysis of variance (ANOVA). Travel speed models based on the clustered time-of-day intervals are developed using important factors identified as having significant effects on speed for different time-of-day periods. ^ It has been found that transit performance varied from different seasons and different time-of-day periods. The geographic location of a transit route segment also plays a role in the variation of the transit performance. The results of this research indicate that advanced data mining techniques have good potential in providing automated techniques of assisting transit agencies in service planning, scheduling, and operations control. ^

位置相关数据的模型及关键技术研究

本文介绍了移动计算领域一个较为年轻的新课题——位置相关数据。位置相关数据是一种向移动用户提供即时、即点信息服务的技术。通过位置相关服务用户在移动过程中可以获得与其所在位置相适应的数据信息。 本文首先对位置相关服务的背景问题、关联技术、系统结构等方面作了概要性的介绍。然后从集合和映射的角度出发，探讨了位置相关数据的数学模型。为了使关系数据库能够支持位置相关查询，本文还分析了关系代数的位置相关性，并通过引入位置绑定算子初步建立了位置相关的关系代数。通过对位置绑定策略的讨论，本文提出了两阶段的位置绑定策略，为位置相关查询的优化提供了思路。 为了提高位置绑定的效率，本文进一步研究了位置绑定数据的索引和缓存方法。利用位置相关数据的数据区域的互斥性，本文在~R~树的基础上作了改进并提出了~Contour-R~树索引及其上的相关算法。新索引方法在保持~R~树灵活性的同时避免了~R~在点查询时的回溯，从而能够提高服务器端的查询效率。位置相关数据缓存是减少服务器查询次数的一种技术。本文提出的跨区域语义缓存方法突破了现有基于单一有效区域缓存方法的限制，使得用户可以根据设备的存储能力自行设置有效区域的尺寸。实验表明，在有效区域面积相同的情况下，跨区域缓存比单一有效区域缓存具有更高的命中率。同时，利用本文给出的旋转表示法，对跨区域缓存进行探测只需要通过简单运算即可完成。

A scaleless data model for direct and progressive spatial query processing

A progressive spatial query retrieves spatial data based on previous queries (e.g., to fetch data in a more restricted area with higher resolution). A direct query, on the other side, is defined as an isolated window query. A multi-resolution spatial database system should support both progressive queries and traditional direct queries. It is conceptually challenging to support both types of query at the same time, as direct queries favour location-based data clustering, whereas progressive queries require fragmented data clustered by resolutions. Two new scaleless data structures are proposed in this paper. Experimental results using both synthetic and real world datasets demonstrate that the query processing time based on the new multiresolution approaches is comparable and often better than multi-representation data structures for both types of queries.