Simulation studies of permeation through two-dimensional ideal polymer networks

We study the diffusion process through an ideal polymer network, using numerical methods. Polymers are modeled by random walks on the bonds of a two-dimensional square lattice. Molecules occupy the lattice cells and may jump to the nearest-neighbor cells, with probability determined by the occupation of the bond separating the two cells. Subjected to a concentration gradient across the system, a constant average current flows in the steady state. Its behavior appears to be a non-trivial function of polymer length, mass density and temperature, for which we offer qualitative explanations.Comment: 8 pages, 4 figure

Scaling for the Percolation Backbone

We study the backbone connecting two given sites of a two-dimensional lattice separated by an arbitrary distance $r$ in a system of size $L$. We find a scaling form for the average backbone mass: $\sim L^{d_B}G(r/L)$, where $G$ can be well approximated by a power law for $0\le x\le 1$: $G(x)\sim x^{\psi}$ with $\psi=0.37\pm 0.02$. This result implies that $\sim L^{d_B-\psi}r^{\psi}$ for the entire range $0<r<L$. We also propose a scaling form for the probability distribution $P(M_B)$ of backbone mass for a given $r$. For $r\approx L, P(M_B)$ is peaked around $L^{d_B}$, whereas for $r\ll L, P(M_B)$ decreases as a power law, $M_B^{-\tau_B}$, with $\tau_B\simeq 1.20\pm 0.03$. The exponents $\psi$ and $\tau_B$ satisfy the relation $\psi=d_B(\tau_B-1)$, and $\psi$ is the codimension of the backbone, $\psi=d-d_B$.Comment: 3 pages, 5 postscript figures, Latex/Revtex/multicols/eps

An investigation into customer perception and behaviour through social media research – an empirical study of the United Airline overbooking crisis

Airlines have been adopting yield management to optimise the perishable seat control problem and overbooking is a common strategy. This study outlines the connections between yield management, crises, and crisis communication. Using big data captured on a social media platform, this study aims to combine traditional yield management with emerging social big data analytics. As part of this, we use the twitter data on the 2017 United Airline (UA) to analyse the overbooking crisis. Our findings shed light on the importance of a more effective orchestration of yield management to avoid the escalation of crises during crisis communication phases

Breast Implants Associated Anaplastic Large Cell Lymphoma Due to Textured Breast Implant

ABSTRACT Textured breast implants came to the market with an important goal: improving aesthetic results and decreasing capsular contracture. Over thirty years, the textured shell of gel-filled and saline implants proved superior to smooth-shell breast implants. Textured implants have some advantages, specifically with shaped implants requiring texturing for position stability. The rate of capsular contracture using textured breast implants is significantly lower compared to smooth breast implants. However, data shows that the textured surface of breast implants has its complications. One of them is the late-onset fluid collection, positive for CD30+, leading to the breast implants associated anaplastic large cell lymphoma. A late seroma doesn’t lead to Anaplastic Large Cell Lymphoma (ALCL); it is a sign of ALCL. Inflammation around the implant in the genetically susceptible patient can lead to ALCL. Although most patients who develop ALCL can be surgically cured if diagnosed early, metastasis has occurred and has led to death in at least 34 reported cases. The significant complication due to the textured part is death. The controversy among plastic surgeons is apparent and different opinions surround the question- Should we continue using Textured Breast Implants? After conducting a two-day hearing on the use of textured breast implants, the Food and Drug Administration concluded that there was not enough evidence-based data to remove textured breast implants from the market. Experts in the plastic surgery field, immunology, and surgical device companies presented the data. They identified many causes that may lead to breast implants associated anaplastic large cell lymphoma and breast implants illness. However, given data locked certainty, that would make textured shell the causative agent for this disease development. All panelists agreed that the industry needs to research and collect evidence-based data in the next decade to answer questions about textured shells and the safety of their use

Security as Simulacra: Surveilling gendered bodies and constructing security out of computation

Student #: 60106041 Abstract Artificial Intelligence has become ubiquitous across the field of security and defence, especially in applications alongside surveillance. In this Dissertation I interrogate the question of how, through application and out of discourse AI impacts the securitization of Muslim women's veiling practices within the EU. I argue that the discourse constructed around the use of AI, through official documents written and commissioned by the various EU bodies, forms a cohesive body. Using discourse analysis, I trace the patterns throughout the documents and connect them to manifestations in rhetoric on the wearing of veils in public at the EU institutional level. Through this method, I conclude that the discourses of AI surveillance manifest in the way laws are applied to women who wear Islamic veils, and their identification as a security threat to Europe as a both a political and conceptual unit. Furthermore, finding that the discourses of security and science intermingle to form a rigid notion of risk which further corners women who are already marginalized by European security frameworks

Bezpečnost jako Simulakra: Sledování pohlavních těl a vytváření bezpečnosti z výpočtů

Student #: 60106041 Abstract Artificial Intelligence has become ubiquitous across the field of security and defence, especially in applications alongside surveillance. In this Dissertation I interrogate the question of how, through application and out of discourse AI impacts the securitization of Muslim women's veiling practices within the EU. I argue that the discourse constructed around the use of AI, through official documents written and commissioned by the various EU bodies, forms a cohesive body. Using discourse analysis, I trace the patterns throughout the documents and connect them to manifestations in rhetoric on the wearing of veils in public at the EU institutional level. Through this method, I conclude that the discourses of AI surveillance manifest in the way laws are applied to women who wear Islamic veils, and their identification as a security threat to Europe as a both a political and conceptual unit. Furthermore, finding that the discourses of security and science intermingle to form a rigid notion of risk which further corners women who are already marginalized by European security frameworks.Katedra bezpečnostních studiíDepartment of Security StudiesFakulta sociálních vědFaculty of Social Science

A mixed integer programming and heuristic algorithm for a warehouses location problem

A warehouses location problem is treated using a mixed integer programming and a heuristic algorithm. A simplification of freight rates schedules, based upon shipments consolidation and a linear regression of rates vs distances was made. Warehousing costs were divided according to fixed and variable and related to the throughput of the warehouses. Consideration was given in the analysis to the choice between owning and leasing each warehouse. In the case studied, the analysis demonstrated that a possible saving of approximately 22 per cent in annual distribution costs could be realized under the optimized warehouse location network.