ON THE DESCRIPTIONAL COMPLEXITY OF THE WINDOW SIZE FOR DELETING RESTARTING AUTOMATA

2013 ◽  
Vol 24 (06) ◽  
pp. 831-846 ◽  
Author(s):  
MARTIN KUTRIB ◽  
FRIEDRICH OTTO
Keyword(s):  
Upper Bound ◽  
Recursive Function ◽  
Window Size ◽  
Input Word ◽  
Trade Off ◽  
Descriptional Complexity ◽  
The Impact ◽  
Current Word ◽  
Restarting Automaton

The restarting automaton was inspired by the technique of ‘analysis by reduction’ from linguistics. A restarting automaton processes a given input word through a sequence of cycles. In each cycle the current word on the tape is scanned from left to right and a single local simplification (a rewrite) is executed. One of the essential parameters of a restarting automaton is the size of its read/write window. Here we study the impact of the window size on the descriptional complexity of several types of deterministic and nondeterministic restarting automata. For all k ≥ 4, we show that the savings in the economy of descriptions of restarting automata that can only delete symbols but not rewrite them (that is, the so-called R- and RR-automata) cannot be bounded by any recursive function, when changing from window size k to window size k + 1. This holds for deterministic as well as for nondeterministic automata, and for k ≥ 5, it even holds for the stateless variants of these automata. However, the trade-off between window sizes two and one is recursive for deterministic devices. In addition, a polynomial upper bound is given for the trade-off between RRWW-automata with window sizes k + 1 and k for all k ≥ 2.

ON THE DESCRIPTIONAL COMPLEXITY OF METALINEAR CD GRAMMAR SYSTEMS

2005 ◽  
Vol 16 (05) ◽  
pp. 1011-1025
Author(s):  
BETTINA SUNCKEL
Keyword(s):  
Recursive Function ◽  
Trade Off ◽  
Descriptional Complexity ◽  
Grammar System ◽  
Trade Offs ◽  
Grammar Systems ◽  
Context Free ◽  
Context Free Grammars

Metalinear CD grammar systems are context-free CD grammar systems where each component consists of metalinear productions. The maximal number of nonterminals in all starting productions is referred to as the width of a CD grammar system. It is shown that between the class of CD grammar systems of width m + 1 and of width m there are savings concerning the size of the grammar system not bounded by any recursive function. This is called a non-recursive trade-off. Furthermore, it is proven that there are non-recursive trade-offs between the class of metalinear CD grammar systems of width m and the class of (2m - 1)-linear context-free grammars. In addition, some decidability results are presented.

Self-Verifying Pushdown and Queue Automata

2021 ◽  
Vol 180 (1-2) ◽  
pp. 1-28
Author(s):  
Henning Fernau ◽  
Martin Kutrib ◽  
Matthias Wendlandt
Keyword(s):  
Recursive Function ◽  
Input Word ◽  
Closure Properties ◽  
Descriptional Complexity ◽  
Trade Offs ◽  
Deterministic Automata ◽  
Context Free ◽  
Pushdown Automata ◽  
Computation Path

We study the computational and descriptional complexity of self-verifying pushdown automata (SVPDA) and self-verifying realtime queue automata (SVRQA). A self-verifying automaton is a nondeterministic device whose nondeterminism is symmetric in the following sense. Each computation path can give one of the answers yes, no, or do not know. For every input word, at least one computation path must give either the answer yes or no, and the answers given must not be contradictory. We show that SVPDA and SVRQA are automata characterizations of so-called complementation kernels, that is, context-free or realtime nondeterministic queue automaton languages whose complement is also context free or accepted by a realtime nondeterministic queue automaton. So, the families of languages accepted by SVPDA and SVRQA are strictly between the families of deterministic and nondeterministic languages. Closure properties and various decidability problems are considered. For example, it is shown that it is not semidecidable whether a given SVPDA or SVRQA can be made self-verifying. Moreover, we study descriptional complexity aspects of these machines. It turns out that the size trade-offs between nondeterministic and self-verifying as well as between self-verifying and deterministic automata are non-recursive. That is, one can choose an arbitrarily large recursive function f, but the gain in economy of description eventually exceeds f when changing from the former system to the latter.

scholarly journals Market buoyancy, information transparency and pricing strategy in the Scottish housing market

Urban Studies ◽  
2021 ◽  
pp. 004209802199178
Author(s):  
Nan Liu
Keyword(s):  
Pricing Strategy ◽  
Selling Price ◽  
Trade Off ◽  
Information Transparency ◽  
North East ◽  
Sealed Bid ◽  
Strategy Changes ◽  
The Impact ◽  
Role Of Information

In housing markets there is a trade-off between selling time and selling price, with pricing strategy being the balancing act between the two. Motivated by the Home Report scheme in Scotland, this paper investigates the role of information symmetry played in such a trade-off. Empirically, this study tests if sellers’ pricing strategy changes when more information becomes available and whether this, in turn, affects the trade-off between the selling price and selling time. Using housing transaction data of North-East Scotland between 1998Q2 and 2018Q2, the findings show that asking price has converged to the predicted price of the property since the introduction of the Home Report. While information transparency reduces the effect of ‘overpricing’ on selling time, there is little evidence to show that it reduces the impact of pricing strategy on the final selling price in the sealed-bid context.

Fast Water Transport Through Sub-5 nm Polyamide Nanofilms: The New Upper-Bound of the Permeance-Selectivity Trade-Off in Nanofiltration

2021 ◽  
Author(s):  
Pulak Sarkar ◽  
Solagna Modak ◽  
Santanu Ray ◽  
Vasista Adupa ◽  
K. Anki Reddy ◽  
...  
Keyword(s):  
Water Transport ◽  
Composite Membrane ◽  
Upper Bound ◽  
Polymer Membranes ◽  
Liquid Transport ◽  
Trade Off ◽  
Commercial Exploitation

Liquid transport through the composite membrane is inversely proportional to the thickness of its separation layer. While the scalable fabrication of ultrathin polymer membranes is sought for their commercial exploitation,...

Interrelationship Among Competition, Diversification and Liquidity Creation: Evidence from Indian Banks

2021 ◽  
Vol 15 (2) ◽  
pp. 183-204
Author(s):  
Pankaj Sinha ◽  
Naina Grover
Keyword(s):  
Inverse Relationship ◽  
Consumer Welfare ◽  
Adverse Impact ◽  
Public And Private ◽  
Jel Codes ◽  
Trade Off ◽  
Private Banks ◽  
Indian Banks ◽  
The Impact

This study analyses the impact of competition on liquidity creation by banks and investigates the dynamics between diversification, liquidity creation and competition for banks operating in India during the period from 2005 to 2018. Using the broad and narrow measures of liquidity creation, an inverse relationship is determined between liquidity creation and competition. The study also indicates a trade-off between pro-competitive policies to improve consumer welfare and the liquidity-destroying effects of competition, and it highlights how diversification affects liquidity creation. Highly diversified banks in India create less liquidity compared with less-diversified banks, both public and private. The liquidity-destroying effects of competition is intensified among highly diversified private banks, which suggest that diversification has not moderated the adverse impact of competition. JEL Codes: G01, G18, G21, G28

scholarly journals Assessing the evidence on case management

2002 ◽  
Vol 181 (1) ◽  
pp. 17-21 ◽  
Author(s):  
S. J. Ziguras ◽  
G. W. Stuart ◽  
A. C. Jackson
Keyword(s):  
Mental Health ◽  
Case Management ◽  
Statistical Power ◽  
Cochrane Collaboration ◽  
Randomised Trials ◽  
Inclusion Criteria ◽  
Management Effectiveness ◽  
Trade Off ◽  
The Cochrane Collaboration ◽  
The Impact

BackgroundEvidence on the impact of case management is contradictory.AimsTo discuss two different systematic reviews (one conducted by the authors and one conducted through the Cochrane collaboration) that came to contradictory conclusions about the impact of case management in mental health services.MethodWe summarised the findings of the two reviews with respect to case management effectiveness, examined key methodological differences between the two approaches and discuss the impact of these on the validity of the results.ResultsThe differences in conclusions between the two reviews result from the differences in inclusion criteria, namely non-randomised trials, data from unpublished scales and data from variables with skewed distributions. The theoretical and empirical effects of these are discussed.ConclusionsSystematic reviewers may face a trade-off between the application of strict criteria for the inclusion of studies and the amount of data available for analysis and hence statistical power. The available research suggests that case management is generally effective.

120 The Experience of Housing Need Amongst Families Caring for Children with Medical Complexity: A Qualitative Study

2021 ◽  
Vol 26 (Supplement_1) ◽  
pp. e85-e88
Author(s):  
Clara Moore ◽  
Kara Grace Hounsell ◽  
Arielle Zahavi ◽  
Danielle Arje ◽  
Natalie Weiser ◽  
...  
Keyword(s):  
Qualitative Study ◽  
Future Research ◽  
Complex Care ◽  
Housing Situation ◽  
Children With Medical Complexity ◽  
Trade Off ◽  
Housing Preferences ◽  
Medical Needs ◽  
Medical Complexity ◽  
The Impact

Abstract Primary Subject area Complex Care Background Caregivers of children with medical complexity (CMC) face many financial, social and emotional stressors related to their child’s medical condition(s). Previous research has demonstrated that financial stress among this population can have an impact on their housing situation. Families of CMC may face other unique housing challenges such as disability accommodations in the home and housing space and layout. Objectives The primary aim of this study was to explore families’ perspectives and experiences of housing need, and its relationship to their child’s health status as it pertains to CMC. Design/Methods We conducted a qualitative study using semi-structured interviews to identify themes surrounding families of CMC’s experiences of housing need. Parents of CMC were recruited through purposive sampling from the Complex Care Program at a tertiary pediatric health sciences centre. Recruitment ceased when thematic saturation was reached, as determined by consensus of the research team. Interviews were recorded, transcribed verbatim, coded, and analyzed using thematic analysis. Results Twenty parents completed the interview, of whom 89% were mothers and 42% identified a non-English language as their first language. Two major themes and five subthemes (in parentheses) were identified: 1) the impact of health on housing (housing preferences, housing possibilities, housing outcome as a trade-off) and 2) the impact of housing on health (health of the caregiver, health of the child). Some parents reported that their child’s medical needs resulted in specific preferences regarding the location and layout of their home. Parents also indicated that their caregiving role often affected their income and home ownership status, which in turn, affected their housing possibilities. Thus, the housing situation (location and layout of the home) was often the result of a trade-off between the parent’s housing preferences and possibilities. Conclusion Housing is a recognized social determinant of health. We found that among CMC, health also appears to be a significant determinant of housing as families reported that the health of their child impacted their housing preferences and the options available to them (possibilities). To support the health of CMC and their families, policies targeting improved access to subsidized housing, improved sources of funding and regulations allowing families who rent to make accessibility changes are vital. Future research should investigate the impact of household income on housing need and identify interventions to support appropriate housing for CMC.

scholarly journals Exploiting correlated molecular-dynamics networks to counteract enzyme activity–stability trade-off

2018 ◽  
Vol 115 (52) ◽  
pp. E12192-E12200 ◽  
Author(s):  
Haoran Yu ◽  
Paul A. Dalby
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Active Site ◽  
Dynamic Networks ◽  
Aromatic Aldehydes ◽  
Active Site Residues ◽  
Trade Off ◽  
Highly Correlated ◽  
Dynamics Simulations ◽  
The Impact

The directed evolution of enzymes for improved activity or substrate specificity commonly leads to a trade-off in stability. We have identified an activity–stability trade-off and a loss in unfolding cooperativity for a variant (3M) of Escherichia coli transketolase (TK) engineered to accept aromatic substrates. Molecular dynamics simulations of 3M revealed increased flexibility in several interconnected active-site regions that also form part of the dimer interface. Mutating the newly flexible active-site residues to regain stability risked losing the new activity. We hypothesized that stabilizing mutations could be targeted to residues outside of the active site, whose dynamics were correlated with the newly flexible active-site residues. We previously stabilized WT TK by targeting mutations to highly flexible regions. These regions were much less flexible in 3M and would not have been selected a priori as targets using the same strategy based on flexibility alone. However, their dynamics were highly correlated with the newly flexible active-site regions of 3M. Introducing the previous mutations into 3M reestablished the WT level of stability and unfolding cooperativity, giving a 10.8-fold improved half-life at 55 °C, and increased midpoint and aggregation onset temperatures by 3 °C and 4.3 °C, respectively. Even the activity toward aromatic aldehydes increased up to threefold. Molecular dynamics simulations confirmed that the mutations rigidified the active-site via the correlated network. This work provides insights into the impact of rigidifying mutations within highly correlated dynamic networks that could also be useful for developing improved computational protein engineering strategies.

Male Youth Activities and Metropolitan Context

1998 ◽  
Vol 30 (3) ◽  
pp. 385-399 ◽  
Author(s):  
S R Holloway
Keyword(s):  
Black Male ◽  
Metropolitan Areas ◽  
White Male ◽  
The United States ◽  
Theoretical Understanding ◽  
Trade Off ◽  
Black And White ◽  
Trade Offs ◽  
Activity Choices ◽  
The Impact

The research reported here examines the impact of metropolitan location on the activity choices of a sample of black and white male youths living in large metropolitan areas in the United States in 1980. The results of the analysis confirm that similar youths living in different metropolitan areas will make different activity choices. Furthermore, black male youths are found to be substantially more sensitive to metropolitan context than white male youths. The analysis also suggests that black and white disadvantaged youths respond differently to metropolitan context in terms of the trade-offs between activities. Disadvantaged black male youths are highly unlikely to be employed in all metropolitan areas and tend to trade-off staying in school with idleness, whereas disadvantaged white male youths tend to trade-off employment with idleness, depending on the metropolitan area they live in. This research confirms the importance of incorporating geographic context into our theoretical understanding of male youths' behavior. We must also, however, continue to address the implications of race as it shapes the context-dependent labor-market experiences of male youths.

Visible marking of wader nests to avoid damage by farmers does not increase nest predation

2017 ◽  
Vol 28 (2) ◽  
pp. 293-301 ◽  
Author(s):  
VÁCLAV ZÁMEČNÍK ◽  
VOJTĚCH KUBELKA ◽  
MIROSLAV ŠÁLEK
Keyword(s):  
Czech Republic ◽  
Nest Predation ◽  
Agricultural Land ◽  
Positive Experience ◽  
The Czech Republic ◽  
Trade Off ◽  
Nest Protection ◽  
Vanellus Vanellus ◽  
The Impact ◽  
Ground Nesting

SummaryOnly a few studies have assessed the predation risk on artificially marked nests, or have examined ways of marking nests to avoid destruction by machinery. Until now, however, neither type of study has directly addressed this apparent trade-off experimentally. The impact of marking the nests of Northern Lapwing Vanellus vanellus with thin 2 m-long conspicuous bamboo poles with the top end highlighted with reflective red or orange spray has been tested for three years in two breeding areas of waders in the Czech Republic. A total of 52 pairs of nests on agricultural land, with each pair consisting of one marked nest and one unmarked reference counterpart nest, were monitored for 2004 nest-days until hatching, agricultural operations or failure. The results proved that marking itself does not result in increased nest predation. The nests found in the early incubation stage were under higher threat of depredation, irrespective of the presence of marking. Our results show that it is possible to find a finely-tuned trade-off in nest marking of ground-nesting birds between risk of damage by agricultural machinery and risk of increased nest predation. Our positive experience with Northern Lapwing, and episodically with three other wader species in the Czech Republic, suggests that this direct nest protection could be used effectively for a wider variety of ground-nesting birds.

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