9 resultados para tweet seats
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
Universities planning the provision of space for their teaching requirements need to do so in a fashion that reduces capital and maintenance costs whilst still providing a high-quality level of service. Space plans should aim to provide sufficient capacity without incurring excessive costs due to over-capacity. A simple measure used to estimate over-provision is utilisation. Essentially, the utilisation is the fraction of seats that are used in practice, or the ratio of demand to supply. However, studies usually find that utilisation is low, often only 20–40%, and this is suggestive of significant over-capacity.
Our previous work has provided methods to improve such space planning. They identify a critical level of utilisation as the highest level that can be achieved whilst still reliably satisfying the demand for places to allocate teaching events. In this paper, we extend this body of work to incorporate the notions of event-types and space-types. Teaching events have multiple ‘event-types’, such as lecture, tutorial, workshop, etc., and there are generally corresponding space-types. Matching the type of an event to a room of a corresponding space-type is generally desirable. However, realistically, allocation happens in a mixed space-type environment where teaching events of a given type are allocated to rooms of another space-type; e.g., tutorials will borrow lecture theatres or workshop rooms.
We propose a model and methodology to quantify the effects of space-type mixing and establish methods to search for better space-type profiles; where the term “space-type profile” refers to the relative numbers of each type of space. We give evidence that these methods have the potential to improve utilisation levels. Hence, the contribution of this paper is twofold. Firstly, we present informative studies of the effects of space-type mixing on utilisation, and critical utilisations. Secondly, we present straightforward though novel methods to determine better space-type profiles, and give an example in which the resulting profiles are indeed significantly improved.
Resumo:
Mounting accuracy of satellite payload and
ADCS (attitude determination and control subsystem) seats
is one of the requirements to achieve the satellite mission
with satisfactory performance. Deviation of the position of
the mounting seat for Multi-Band-Earth-Imager (MBEI) is
caused by cracks in the plate of the basis unit and bracket
for attachment of MBEI. These cracks were detected during
inspection of the satellite strength mock-up after vibration
testing for air transportation phase. Most probable reason of
the cracking is fatigue damage as strength mock-up
structure was subjected to prolonged vibration loading
during various loading cases. Total vibration duration
during testing is about 56 hours. In order to study the
cracking reasons, finite element modeling of the structural
parts of the basis unit including MBEI bracket and
instrument MBEI is subjected to harmonic response to
simulate vibration loading for the case of air transportation.
Numerical results are compared with the experimental ones,
and mechanical design of the basis-plate unit is modified
Resumo:
The small-satellite thermal subsystem main function is to control temperature ranges on equipments, and payload for the orbit specified. Structure subsystem has to ensure the satellite structure integrity. Structure integrity should meet two constraints; first constraint is accepted fatigue damage due to cyclic temperature, and second one is tolerable mounting accuracy at payload and Attitude Determination and Control Subsystem (ADCS) equipments’ seats. First, thermal analysis is executed by applying finitedifference method (IDEAS) and temperature profile for satellite components case is evaluated. Then, thermal fatigue analysis is performed applying finite-element analysis (ANSYS) to calculate the resultant damage due to on-orbit cyclic stresses, and structure deformations at the payload and ADCS equipments seats.
Resumo:
Mounting accuracy of satellite payload and ADCS (attitude determination and control subsystem) seats is one of the requirements to achieve the satellite mission with acceptable performance. Components of mounting inaccuracy are technological inaccuracies, residual plastic deformations after loading (during transportation and orbital insertion), elastic deformations, and thermal deformations during orbital operation. This paper focuses on estimation of thermal deformations of satellite structure. Thermal analysis is executed by applying finite-difference method (IDEAS) and temperature profile for satellite components case is evaluated. Then, Perform thermal finite-element analysis applying the finite-difference model results as boundary conditions; and calculate the resultant thermal strain. Next, applying the resultant thermal strain, perform finite-element structure analysis to evaluate structure deformations at the payload and ADCS equipments seats.
Resumo:
Mechanical swivel seat adaptations are a key aftermarket disability modification to any small-to medium-sized passenger vehicle. However, the crashworthiness of these devices is currently unregulated and the existing 20g dynamic sled testing approach is prohibitively expensive for prototype assessment purposes. In this paper, an alternative quasi-static test method for swivel seat assessment is presented, and two different approaches (free-body diagram and multibody modelling) validated through published experimental data are developed to determine the appropriate loading conditions to apply in the quasi-static testing.Results show the two theoretical approaches can give similar results for estimating the quasi-static loading conditions, and this depends on the seatbelt configuration. Application of the approach to quasi-static testing of both conventional seats and those with integrated seat belts showed the approach to be successful and easy to apply. It is proposed that this method be used by swivel seat designers to assess new prototypes prior to final validation via the traditional 20g sled test.
Resumo:
When a user of a microblogging site authors a microblog
post or browses through a microblog post, it provides cues as to what
topic she is interested in at that point in time. Example-based search
that retrieves similar tweets given one exemplary tweet, such as the one
just authored, can help provide the user with relevant content. We investigate
various components of microblog posts, such as the associated
timestamp, author’s social network, and the content of the post, and
develop approaches that harness such factors in finding relevant tweets
given a query tweet. An empirical analysis of such techniques on real
world twitter-data is then presented to quantify the utility of the various
factors in assessing tweet relevance. We observe that content-wise similar
tweets that also contain extra information not already present in the
query, are perceived as useful. We then develop a composite technique
that combines the various approaches by scoring tweets using a dynamic
query-specific linear combination of separate techniques. An empirical
evaluation establishes the effectiveness of the composite technique, and
that it outperforms each of its constituents.
Resumo:
Analysing public sentiment about future events, such as demonstration or parades, may provide valuable information while estimating the level of disruption and disorder during these events. Social media, such as Twitter or Facebook, provides views and opinions of users related to any public topics. Consequently, sentiment analysis of social media content may be of interest to different public sector organisations, especially in the security and law enforcement sector. In this paper we present a lexicon-based approach to sentiment analysis of Twitter content. The algorithm performs normalisation of the sentiment in an effort to provide intensity of the sentiment rather than positive/negative label. Following this, we evaluate an evidence-based combining function that supports the classification process in cases when positive and negative words co-occur in a tweet. Finally, we illustrate a case study examining the relation between sentiment of twitter posts related to English Defence League and the level of disorder during the EDL related events.
Resumo:
With Tweet volumes reaching 500 million a day, sampling is inevitable for any application using Twitter data. Realizing this, data providers such as Twitter, Gnip and Boardreader license sampled data streams priced in accordance with the sample size. Big Data applications working with sampled data would be interested in working with a large enough sample that is representative of the universal dataset. Previous work focusing on the representativeness issue has considered ensuring the global occurrence rates of key terms, be reliably estimated from the sample. Present technology allows sample size estimation in accordance with probabilistic bounds on occurrence rates for the case of uniform random sampling. In this paper, we consider the problem of further improving sample size estimates by leveraging stratification in Twitter data. We analyze our estimates through an extensive study using simulations and real-world data, establishing the superiority of our method over uniform random sampling. Our work provides the technical know-how for data providers to expand their portfolio to include stratified sampled datasets, whereas applications are benefited by being able to monitor more topics/events at the same data and computing cost.
Resumo:
The process of constituency boundary revision in Ireland, designed to satisfy what is perceived as a rigid requirement that a uniform deputy-population ratio be maintained across constituencies, has traditionally consumed a great deal of the time of politicians and officials. For almost two decades after a High Court ruling in 1961, the process was a political one, was highly contentious, and was marked by serious allegations of ministerial gerrymandering. The introduction in 1979 of constituency commissions made up of officials neutralised, for the most part, charges that the system had become too politicised, but it continued the process of micro-management of constituency boundaries. This article suggests that the continuing problems caused by this system – notably, the permanently changing nature of constituency boundaries and resulting difficulties of geographical identification – could be resolved by reversion to the procedure that is normal in proportional representation systems: periodic post-census allocation of seats to constituencies whose boundaries are based on those of recognised local government units and which are stable over time. This reform, replacing the principle of redistricting by the principle of reapportionment, would result in more recognisable constituencies, more predictable boundary trajectories over time, and a more efficient, fairer, and speedier process of revision.