9 research outputs found
Algorithms for small spanning trees
No full textIn this paper we consider the well known NP-hard problem k-MST. We aregiven a weighted complete graph and we want to find a minimum weightspanning tree which spans only k vertices (with fixed k) of the graph.We consider the special case in which the edge weights correspond toEuclidean distances. This case is relevant for the applications inreal-time situations like fault-tolerant networks or oil rigslocation.Here, we propose two application algorithms, which are less effective(from the theoretical approximation point of view) that those presentin literature, but are more efficient. The efficiency of the algorithmis extremely important for the applications.We tested the performance of the proposed algorithms by comparing thesolutions found and the computation times with other known algorithms
Local Restoration for Trees and Arborescences
No full textProtocols belonging to the Spanning Tree Protocol (STP) route traffic demands on tree topologies that are evaluated through shortest path procedures. In this paper we deal with the problem of assigning costs to the arcs of a network in order to guarantee that SPT protocols efficiently re-route traffic demands in failure situations: namely, without redirecting traffic demands that are not affected by the failure. We say that a communication network has the local tree-restoration property if there exists a set of costs for its arcs such that the above property holds. We show that an undirected network has the local tree-restoration property if and only if it is 2-connected. In particular, we provide a quite simple procedure for assigning costs to the arcs of a 2-connected network so that the property holds. For the directed case, we show that deciding whether a network has the local tree-restoration property is NP-hard, even in some “simple” cases.DISOP
Combinatorial structures for communication networks
No full textThis thesis deals with a class of theoretical problems arising in applications
in communication networks. The dissertation is mainly divided in two parts.
In the first part, we attempt to solve a set of survivability network design
problems. Network survivability refers to the guarantees that a communication
network provides in the event that one or more failures occur. An attack or
failure can significantly reduce the capability of the communication network to
efficiently deliver basic services to users. In several cases, when a failure occurs,
the network operators are interested in restoring traffic by re-routing it through
different links. Since re-routing traffic can be rather expensive and may cause
delays in transmissions, a key property is that of requiring that traffic which is
not affected by the failure is not redirected in failure situations.
We study the problem of determining whether a given network, where the traffic
is commonly routed on the edges of a shortest path tree (e.g. Ethernet networks
with the Spanning Tree Protocol), may satisfy the above mentioned property.
We provide computational complexity results for directed and undirected net-
works. In particular, for the directed case, we prove that such problem is in
general NP-hard and that it remains NP-hard also in some special cases. More-
over, we show how to assign weights to the links of the network in order to
configure a routing topology with the above mentioned property.
In the second part of the thesis, we deal with a problem regarding broadcast-
ing in telecommunication networks. We investigate a new version of the well
known Minimum Broadcast Time problem which has been deeply studied in
the past, since broadcasting is a basic primitive in the communication networks
area. Fundamental requirements for a broadcast process are that it completes in
the quickest way and that, at the end of the procedure, all the peers in the net-
work are informed. In this thesis we deal with an objective function that takes
into account the quality of the service associated with the broadcast, namely
the minimization of the average broadcast time of the peers.
We show that the considered version of the broadcast problem is an NP-hard
problem. Indeed, the problem becomes polynomially solvable, if the instance
graph is a tree. We also provide a distributed approximation algorithm for our
version of the broadcast problem, in which every network node does not know
the network topology
Standard purification methods are not sufficient to remove micellular lipophilic dye from polymer nanoparticle solution
No full textThis article was originally published in RSC Pharmaceutics. The version of record is available at: https://doi.org/10.1039/D5PM00013K.
© 2025 The Author(s). Published by the Royal Society of Chemistry.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (http://creativecommons.org/licenses/by-nc/3.0/).Tracking nanoparticles’ location is imperative for understanding cellular interactions, pharmacokinetics, and biodistribution. DiD is a lipophilic dye commonly used to label nanoparticles for trafficking studies. Herein, we show that DiD micelles form in polymer NP solutions during synthesis and can lead to false positive results in downstream assays. Potential methods to remove these micelles are also described.The authors thank Dr John Sperduto for his input and expertise as well as the Delaware Biotechnology Institute for their support. This work was supported by the National Institutes of Health under award numbers R35GM149292 and R35GM119659 and by the University of Delaware Summer Scholars Program. E. H. S. acknowledges support from the National Science Foundation Graduate Research Fellowship Program under award number 1940700
Emilio Ghione and the Mask of Za La Mort
No full textThis study aims to examine the cultural impact of Emilio Ghione's Za La Mort films (1914-1924) on Italian culture. These films constitute a significant Italian combination of several early cinema genres and sub-genres, such as the apache film, the traces of which have almost entirely disappeared. More broadly, the changing interpretations of Za La Mort figure allow us to understand wider shifts in Italian and European popular culture.
The first chapter of the study considers the wealth of influences from European popular culture that Emilio Ghione merged into the apache films, such as the apache sub-culture in Paris. The second chapter of the study then reconstructs the Za La Mort filmography, most of which has now been lost, from film viewings and archival documents. The third chapter considers Emilio Ghione's Za La Mort novels and theatrical productions in the years 1922-1930, and Ghione's attempts to make Za La Mort a more Fascist and nationalistic figure. The fourth chapter considers the enduring figure of Za La Mort in Italian popular culture, especially in Raffaele Matarazzo's Fumeria D'Oppio and a 1940's fumetti series. The fifth chapter considers the audience reception of the Za La Mort films from the limited remaining evidence and, positioning the series between the Cinema of Attractions of the 1900s and the Classical Cinema of the mid-1920's, analyses how the Za La Mort films were constructed to please a predominantly working class audience that valued spectacular thrills and great acting performances over narrative consistency and stable characterisation.
This research re-establishes the importance of one of Italian cinema's most important film-makers of the silent period, and his enduring importance as a popular cultural figure in Italy
Raising Māori Student Achievement - Journeys of Success
No full textEducational success for Māori students is influenced by confidence in one’s identity, positive role models and support; and positive attitudes to learning and success.
This project asked Māori tertiary graduates about their educational experiences. Half of the participants in this study had successfully completed secondary school and the other half did not complete secondary school education. This selection of participants was selected to highlight that although some students don’t complete secondary school it is still possible to successfully pursue and complete tertiary level qualifications. The feedback given from the participants highlighted the positive factors that influenced their successful completion. From these factors recommendations have been developed to support Māori student success. The objective of this study is to encourage the development of increased self-confidence for Māori rangatahi and to promote the continuation of lifelong learning.
When Māori students are supported both at school and in the home they are more likely to achieve educational success, particularly at secondary school level. Similarly, at tertiary level study; students who graduate with a completed degree qualification are likely to have had positive support and successful role models, they are likely to be secure within their own identity and wh!nau network. Māori students that successfully complete tertiary study are more likely to have positive attitudes to learning and to achieving; knowing how to access support and feeling confident in their efforts.
The key to this study is the link between successful completion of secondary school and the follow-on to successful tertiary study. When Māori students are supported appropriately in the development of their identity their confidence soon follows. This support would ideally come from wh!nau in the home and the school. When Māori students are confident in their learning journeys through high levels of confidence in identity they are more likely to persevere under pressure and despite setbacks.
Influencing factors to developing self-confidence for Māori students include awareness of Te Reo Māori and Tikanga Māori, responsibility at home, responsibility at school and the positive influence of role models. The study then concludes by providing recommendations for learners, educators and wh!nau to support the educational achievement of their tamariki
