Transactional Support for Mobile Databases

2005 ◽  
pp. 701-706
Author(s):  
Hong Va Leong
Keyword(s):  
Strong Support ◽  
Database Systems ◽  
Computing Environment ◽  
Mobile Environment ◽  
Database Access ◽  
Mobile Databases ◽  
Client Server ◽  
The Past ◽  
Database Research ◽  
Mobile Clients

With the widespread deployment of wireless communication infrastructure in the past decade, accessing information online while a client is on the move becomes a concrete possibility. Such a computing environment is often referred to as a mobile environment (Imielinski & Badrinath, 1994). A typical group of applications that deserve strong support under the mobile environment would be database access. Database systems that support operations initiated from mobile clients are referred to as mobile databases (Leong & Si, 1997). We have witnessed a tremendous growth in mobile database research in the past ten years. Yet only the most primitive results have been incorporated in real applications. This is due to the additional dimensions of complexity that the mobile environment has introduced, beyond standard client/server computing environment.

Robust Query Processing in Database Systems*

2018 ◽  
Author(s):  
Jayant Haritsa
Keyword(s):  
Query Language ◽  
Database Systems ◽  
Research Community ◽  
Management Systems ◽  
Intensive Study ◽  
Query Formulation ◽  
The Past ◽  
Database Research ◽  
Execution Strategy ◽  
The Ideal

Database management systems constitute the backbone of today’s information-rich society, providing a congenial environment for handling enterprise data during its entire life cycle of generation, storage, maintenance and processing. The defacto standard user interface to query the information present in the database is SQL (Structured Query Language). An organic USP of SQL is its declarative persona, which enables users to focus solely on query formulation, leaving it to the database system to identify an efficient execution strategy. Paradoxically, however, the declarative constitution of SQL is also its Achilles heel. This is because the execution strategies chosen by the system often turn out, in hindsight, to be highly sub-optimal as compared to the ideal choice. Unfortunately, due to the intrinsic technical complexities and challenges, solutions to this long-standing problem have remained chronically elusive despite intensive study by the database research community over the past five decades.

Toward Unity among Environmentalists

1995 ◽  
Author(s):  
Bryan G. Norton
Keyword(s):  
Resource Use ◽  
Wide Spectrum ◽  
Strong Support ◽  
Environmental Issues ◽  
Value Systems ◽  
Special Interests ◽  
Unified Approach ◽  
Policy Makers ◽  
The Past ◽  
Control Growth

Today, six out of ten Americans describe themselves as "active" environmentalists or as "sympathetic" to the movement's concerns. The movement, in turn, reflects this millions-strong support in its diversity, encompassing a wide spectrum of causes, groups, and sometimes conflicting special interests. For far-sighted activists and policy makers, the question is how this diversity affects the ability to achieve key goals in the battle against pollution, erosion, and out-of-control growth. This insightful book offers an overview of the movement -- its past as well as its present -- and issues the most persuasive call yet for a unified approach to solving environmental problems. Focusing on examples from resource use, pollution control, protection of species and habitats, and land use, the author shows how the dynamics of diversity have actually hindered environmentalists in the past, but also how a convergence of these interests around forward-looking policies can be effected, despite variance in value systems espoused. The book is thus not only an assessment of today's movement, but a blueprint for action that can help pull together many different concerns under a common banner. Anyone interested in environmental issues and active approaches to their solution will find the author's observations both astute and creative.

scholarly journals Minimization in Cooperative Response to Failing Database Queries

1997 ◽  
Vol 06 (02) ◽  
pp. 95-149 ◽  
Author(s):  
Parke Godfrey
Keyword(s):  
Optimal Algorithm ◽  
Simple Algorithm ◽  
Search Space ◽  
Database Systems ◽  
Identification Problems ◽  
Database Queries ◽  
The Past ◽  
Cause Of Failure ◽  
Algorithmic Approaches ◽  
Answer Set

When a query fails, it is more cooperative to identify the cause of failure, rather than just to report the empty answer set. When there is not a cause per se for the query's failure, it is then worthwhile to report the part of the query which failed. To identify a Minimal Failing Subquery (MFS) of the query is the best way to do this. (This MFS is not unique; there may be many of them.) Likewise, to identify a Maximal Succeeding Subquery (XSS) can help a user to recast a new query that leads to a non-empty answer set. Database systems do not provide the functionality of these types of cooperative responses. This may be, in part, because algorithmic approaches to finding the MFSs and the XSSs to a failing query are not obvious. The search space of subqueries is large. Despite work on MFSs in the past, the algorithmic complexity of these identification problems had remained uncharted. This paper shows the complexity profile of MFS and XSS identification. It is shown that there exists a simple algorithm for finding an MFS or an XSS by asking N subsequent queries, in which N is the length of the query. To find more MFSs (or XSSs) can be hard. It is shown that to find N MFSs (or XSSs) is NP-hard. To find k MFSs (or XSSs), for a fixed k, remains polynomial. An optimal algorithm for enumerating MFSs and XSSs, ISHMAEL, is developed and presented. The algorithm has ideal performance in enumeration, finding the first answers quickly, and only decaying toward intractability in a predictable manner as further answers are found. The complexity results and the algorithmic approaches given in this paper should allow for the construction of cooperative facilities which identify MFSs and XSSs for database systems. These results are relevant to a number of problems outside of databases too, and may find further application.

The Empathy-Altruism Hypothesis

2017 ◽  
Author(s):  
C. Daniel Batson
Keyword(s):  
Strong Support ◽  
Affirmative Answer ◽  
Empathic Concern ◽  
Motivational State ◽  
Altruistic Motivation ◽  
Parental Nurturance ◽  
The Past ◽  
Practical Implications

Do we humans ever, in any degree, care for others for their sakes and not simply for our own? The empathy-altruism hypothesis offers an affirmative answer to this question. It claims that empathic concern (defined as “other-oriented emotion elicited by and congruent with the perceived welfare of another in need”) produces altruistic motivation (“a motivational state with the ultimate goal of increasing the other’s welfare”). Research over the past 40 years testing this hypothesis against egoistic alternatives has provided quite strong support. Empathy-induced altruistic motivation does seem to be within the human repertoire. This empathy-induced altruism may have its biological roots in generalized parental nurturance. Practical implications of the empathy-altruism hypothesis include both benefits and liabilities—for the targets of empathy, for others, and for the person feeling empathic concern. Implications of the empathy-altruism research for the content and conduct of compassion science are suggested.

Comparison of the morphology of the adult males of the rhizoecine, phenacoccine and pseudococcine mealybugs (Hemiptera: Sternorrhyncha: Coccoidea), with the recognition of the family Rhizoecidae Williams

Zootaxa ◽  
2012 ◽  
Vol 3291 (1) ◽  
pp. 1 ◽  
Author(s):  
CHRIS HODGSON
Keyword(s):  
Adult Male ◽  
Strong Support ◽  
Scale Insects ◽  
Adult Males ◽  
Phenacoccus Solenopsis ◽  
Maconellicoccus Hirsutus ◽  
The Past ◽  
Male Characters ◽  
The Family ◽  
Male Morphology

In the past, the morphology of adult males of Coccoidea has provided strong support for diagnosing the higher taxonstatus of scale insects (Coccoidea). In particular, studies on adult male morphology have produced some of the stron-gest evidence for considering the Putoidae and Eriococcidae (as then defined) as separate families from the Pseudo-coccidae. This paper uses adult male morphology to assess the relationships of the Pseudococcidae and the hypogaeicand myrmecophilous mealybugs. The latter most often are classified as a subfamily (Rhizoecinae) of the Pseudococ-cidae. In order to diagnose the latter taxa, the adult males of fifteen named species of hypogaeic rhizoecine mealybugs(Kissrhizoecus hungaricus Kozár & Konczné Benedicty, Rhizoecus cacticans (Hambleton), Rh. coffeae Laing, Rh.dianthi Green, Rh. falcifer Künckel d’Herculais, Rh. kazachstanus Matesova, Ripersiella cryphia (Williams), Ri.hibisci (Kawai & Takagi), Ri. kondonis (Kuwana), Ri. malschae (Williams), Ri. puhiensis (Hambleton), Capitisetellamigrans (Green) and Pseudorhizoecus proximus Green) plus two unidentified Ripersiella species are described. Inaddition, the adult males of a Xenococcus sp., three Eumyrmococcus spp. and two Neochavesia spp. are illustratedfrom previously published papers and the adult male of another Neochavesia sp. is described and illustrated. In orderto compare the diagnoses of the above taxa with that of adult males of Pseudococcidae (minus the Rhizoecinae), theadult males of two apterous pseudococcid mealybugs are described or redescribed: Asaphococcus agninus Cox andthe myrmecophilous Promyrmococcus dilli Williams, both belonging to the Pseudococcinae. In addition, threemacropterous Pseudococcidae, namely Phenacoccus solenopsis Tinsley (Phenacoccinae), Planococcus glaucus(Maskell) and Maconellicoccus hirsutus (Green) (Pseudococcinae) are also described and/or illustrated. Prior to thisstudy, the hypogaeic and myrmecophilous mealybugs generally were included in the subfamily Rhizoecinae of thePseudococcidae, with the hypogaeic mealybugs in tribe Rhizoecini and the myrmecophilous mealybugs in Xenococ-cini. Based on the present study and on phylogenetic data, it is concluded that the rhizoecine mealybugs form a sepa-rate family from the Pseudococcidae — Rhizoecidae Williams. This family is considered here to include twosubfamilies, Rhizoecinae Williams and Xenococcinae Tang. Based on adult male characters, there is little support forthe present generic divisions of the Rhizoecinae. Keys are given for separating the adult males of Rhizoecidae from those of Pseudococcidae, and for separating the known adult males within each subfamily.

Cooperative Caching in a Mobile Environment

2007 ◽  
pp. 154-159
Author(s):  
S. Lim
Keyword(s):  
Cooperative Caching ◽  
Mobile Environment ◽  
Caching Strategy ◽  
Mobile Clients

In this article, we concentrate particularly on cooperative caching, which is basically a type of caching strategy that not only allows mobile clients to retrieve database items from the servers, but also from the cache in their peers.

scholarly journals Outracing Lung Signal Decay – Potential of Ultrashort Echo Time MRI

2018 ◽  
Vol 191 (05) ◽  
pp. 415-423 ◽  
Author(s):  
Mark Wielpütz ◽  
Simon Triphan ◽  
Yoshiharu Ohno ◽  
Bertram Jobst ◽  
Hans-Ulrich Kauczor
Keyword(s):  
Parallel Imaging ◽  
Proton Density ◽  
Ultrashort Echo Time ◽  
The Past ◽  
Signal Decay ◽  
Database Research ◽  
Pulmonary Parenchyma ◽  
Echo Time ◽  
Multiple Challenges ◽  
Magnetic Resonance Imaging Mri

Background Magnetic resonance imaging (MRI) of the pulmonary parenchyma is generally hampered by multiple challenges related to patient respiratory- and circulation-related motion, low proton density and extremely fast signal decay due to the structure of the lungs evolved for gas exchange. Methods Systematic literature database research as well as annual participation in conferences dedicated to pulmonary MRI for more than the past 20 years by at least one member of the author team. Results and Conclusion The problem of motion has been addressed in the past by developments such as triggering, gating and parallel imaging. The second problem has, in part, turned out to be an advantage in those diseases that lead to an increase in lung substance and thus an increase in signal relative to the background. To reduce signal decay, ultrashort echo time (UTE) methods were developed to minimize the time between excitation and readout. Having been postulated a while ago, improved hardware and software now open up the possibility of achieving echo times shorter than 200 µs, increasing lung signal significantly by forestalling signal decay and more effectively using the few protons available. Such UTE techniques may not only improve structural imaging of the lung but also enhance functional imaging, including ventilation and perfusion imaging as well as quantitative parameter mapping. Because of accelerating progress in this field of lung MRI, the review at hand seeks to introduce some technical properties as well as to summarize the growing data from applications in humans and disease, which promise that UTE MRI will play an important role in the morphological and functional assessment of the lung in the near future. Key Points:  Citation Format

Design and Implementation of the Universal Database Query Middleware Based on Web Services

2013 ◽  
Vol 411-414 ◽  
pp. 572-575
Author(s):  
Gang Ding ◽  
Hong Min Nie ◽  
Ying Zhe Liu
Keyword(s):  
Web Services ◽  
Integration Method ◽  
Database Systems ◽  
Database Integration ◽  
Query Interface ◽  
Database Query ◽  
Database Access ◽  
Design And Implementation ◽  
Data Source ◽  
The Difference

Nowadays, a variety of database systems coexist and the application softwares access and operation for database is often custom-written, which can lead to more complicated cross-database access. Through analysis of the operational process of the database middleware, adding the generic database query middleware eQueryMW which can shield the difference of the data source to the traditional three-tier architecture as the middleware level can realize the access of relational heterogeneity database, providing a unified database query interface and cross-database integration method for the users.

Giving meaning to the addition algorithm

1972 ◽  
Vol 19 (5) ◽  
pp. 345-348
Author(s):  
Irv King
Keyword(s):  
Elementary School ◽  
School Children ◽  
Elementary School Children ◽  
Strong Support ◽  
The Past ◽  
Alternative Approach

In the February 1971 issue of the Arithmetic Teacher, Henry Van Engen stated his belief that the formalism of the new mathematics programs is inappropriate for elementary school children. My experiences over the past few years lend strong support to Van Engen's statement, and in this article I examine one specific use of such formalism—the attempt to give meaning to the algorithms of arithmetic. After the attempt is analyzed, an alternative approach will be presented. Although my comments apply to all four basic operations, the discussion will be restricted to the addition algorithm.

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