Aprendizaje automático en metaheurísticas

La logística colaborativa supone una estrategia útil que permite a las empresas ahorrar costes y proporcionar mejor servicio a sus clientes, especialmente a través de centros de cross-docking donde, en lugar de almacenar mercancía, se consolida y prepara, con un tiempo de permanencia inferior a las 24 horas. Con los centros de cross-docking surgen varios problemas, entre ellos la localización de los centros, la asignación de camiones a las puertas del cross-dock, la gestión del flujo interno o del recorrido de los vehículos. En este trabajo de fin de grado, se aborda el problema de optimización de asignación de camiones a puertas de un centro de crossdocking, el cual es computacionalmente difícil y resulta de interés en un escenario real. El objetivo es asignar los camiones de los proveedores a puertas de entrada y los de clientes a puertas de salida, minimizando el recorrido interno en el cross-dock. En este trabajo se proponen 6 algoritmos metaheurísticos para resolver el problema, donde se aplica aprendizaje automático a 2 de ellos, y se prueban en un conjunto de 50 instancias de la literatura científica. Además, se generan instancias adicionales para ampliar las que encontramos en la literatura, y se visualizan gráficamente las soluciones obtenidas del problema.Collaborative logistics strategies are useful because they allow companies to save costs and provide better service to their customers, especially through cross-docking centres where, instead of storing goods, they are consolidated and prepared, where shipments typically spend less than 24 hours in the cross-dock. Several problems arise with cross-docking centres, including the location of the centres, the assignment of trucks to the cross-dock doors, the internal flow management or the vehicles routing management. In this work, the Cross-Docking Assignment Problem (CDAP) is addressed, which is a challenging optimization problem in supply chain management with important practical applications in the trucking industry. The objective is to assign supplier trucks to inbound doors and customer trucks to outbound doors, while minimizing the internal path in the cross-dock. In this work, 6 metaheuristic algorithms are proposed to solve the problem, where machine learning is applied to 2 of them, and evaluated on a set of 50 instances obtained from the scientific literature. Furthermore, additional instances are generated to extend those found in the literature, and the obtained solutions are graphically visualized

Dehn quandles of groups and orientable surfaces

Motivated by the construction of free quandles and Dehn quandles of orientable surfaces, we introduce Dehn quandles of groups with respect to their subsets. As a characterisation, we prove that Dehn quandles are precisely those quandles which embed naturally into their enveloping groups. We prove that the enveloping group of the Dehn quandle of a given group with respect to its generating set is a central extension of that group, and that enveloping groups of Dehn quandles of Artin groups and link groups with respect to their standard generating sets are the groups themselves. We discuss orderability of Dehn quandles and prove that free involutory quandles are left orderable whereas certain generalised Alexander quandles are bi-orderable. Specialising to surfaces, we give generating sets for Dehn quandles of mapping class groups of orientable surfaces with punctures and compute their automorphism groups. As applications, we recover a result of Niebrzydowski and Przytycki proving that the knot quandle of the trefoil knot is isomorphic to the Dehn quandle of the torus and also extend a result of Yetter on epimorphisms of Dehn quandles of orientable surfaces onto certain involutory homological quandles. Finally, we show that involutory quotients of Dehn quandles of closed orientable surfaces of genus less than four are finite.Comment: 32 pages, 7 figure

Factoring periodic maps into Dehn twists

Let $\text{Mod}(S_g)$ be the mapping class group of the closed orientable surface $S_g$ of genus $g \geq 1$. In this paper, we develop various methods for factoring periodic mapping classes into Dehn twists, up to conjugacy. As applications, we develop methods for factoring certain roots of Dehn twists as words in Dehn twists. We will also show the existence of conjugates of periodic maps of order $4g$ and $4g+2$, for $g\geq 2$, whose product is pseudo-Anosov

Knowledge, attitudes and practices towards COVID-19 among Pakistani residents: Information access and low literacy vulnerabilities

Background: Coronavirus disease (COVID-19) has accentuated the need for speedy access to information. Digital divide and socio-demographic disparity create an information hiatus and therefore unhealthy practices with regard to dealing with COVID-19, particularly in low- and middle-income countries.Aims: We assessed knowledge, attitudes, practices and their determinants regarding COVID-19 in Pakistan during March-April 2020.Methods: 905 adults ≥18 years (males and females) participated: 403 from a web-based survey; 365 from an urban survey; and 137 from a rural survey. Frequency of adequate knowledge, attitudes and practices for the three populations was determined based on available global guidelines. Multivariable logistic regression analysis determined factors of adequacy of knowledge, attitudes, practices, and association of knowledge with attitudes and practices.Results: Mean age of the participants was 33.5 (+ SD 11.1) years, 51% were females. More females and young adults (18-30 years) participated in the web-based survey. The urban survey and web-based survey participants had significantly higher adequate knowledge (2-7 times) and practices (4-5 times) towards COVID-19. Adequate knowledge had a significant influence on healthy attitudes and practices for COVID-19, after adjustment for covariates. Overall, two-thirds of the population had high levels of fear about COVID-19, which was highest among the rural survey population.Conclusion: Substantial gaps exist in adequate knowledge, attitudes and practices, particularly among rural populations, and underscores the variation in access to information according to level of education and access to the internet. Thus, a comprehensive, contextually congruent awareness raising strategy is urgently needed to confront COVID-19 among these populations

A Review on Malicious URL Detection using Machine Learning Systems

Malicious web sites pretendsignificant danger to desktop security and privacy.These links become instrumental in giving partial or full system control to the attackers. This results in victim systems, which get easily infected and, attackers can utilize systems for various cyber-crimes such as stealing credentials, spamming, phishing, denial-of-service and many more such attack. Detection of such website is difficult because of thephishing campaigns and the efforts to avoid blacklists.To look for malicious URLs, the first step is usually to gather URLs that are liveon the Internet. There are various stages to detect this URLs such as collection of dataset, extracting feature using different feature extraction techniques and Classification of extracted feature. This paper focus on comparative analysis of malicious URL detection techniques

Securing Web Accounts Using Graphical Password Authentication through MD5 Algorithm

Today, most Internet applications still uses traditional text based passwords for the authentication. Two conflict cases of traditional password i.e. if user choose simple password it will easy to guess by attacker. The other hand, if a password is strong then it is often hard to remember for user. Instead of a text password user will be choose graphical password scheme that uses MD5. In MD5 images that converted into binary code. Here binary code will be the password for user. Thus, graphical password is secure than existing graphical password techniques because every time user needs to enter different set of code for authentication i.e. every time new password gets generated making Dictionary attacks, Brute Force attack, and other attacks infeasible. Because of these advantages, there is a growing interest in graphical password. In addition user can use ?document sharing? feature after authentication process and also graphical passwords can be applied to workstation, web log-in applications, ATM machines and mobile device

T Cell Responses to Neural Autoantigens Are Similar in Alzheimer’s Disease Patients and Age-Matched Healthy Controls

Alzheimer’s disease (AD), a chronic multifactorial and complex neurodegenerative disorder is a leading cause of dementia. Recently, neuroinflammation has been hypothesized as a contributing factor to AD pathogenesis. The role of adaptive immune responses against neuronal antigens, which can either confer protection or induce damage in AD, has not been fully characterized. Here, we measured T cell responses to several potential antigens of neural origin including amyloid precursor protein (APP), amyloid beta (Aβ), tau, α-synuclein, and transactive response DNA binding protein (TDP-43) in patients with AD and age-matched healthy controls (HC). Antigen-specific T cell reactivity was detected for all tested antigens, and response to tau-derived epitopes was particularly strong, but no significant differences between individuals with AD and age-matched HC were identified. We also did not observe any correlation between the antigen-specific T cell responses and clinical variables including age, gender, years since diagnosis and cognitive score. Additionally, further characterization did not reveal any differences in the relative frequency of major Peripheral Blood Mononuclear Cells (PBMC) subsets, or in the expression of genes between AD patients and HC. These observations have not identified a key role of neuronal antigen-specific T cell responses in AD

α-Synuclein-specific T cell reactivity is associated with preclinical and early Parkinson’s disease

A diagnosis of motor Parkinson’s disease (PD) is preceded by a prolonged premotor phase with accumulating neuronal damage. Here we examined the temporal relation between α-synuclein (α-syn) T cell reactivity and PD. A longitudinal case study revealed that elevated α-syn-specific T cell responses were detected prior to the diagnosis of motor PD, and declined after. The relationship between T cell reactivity and early PD in two independent cohorts showed that α-syn-specific T cell responses were highest shortly after diagnosis of motor PD and then decreased. Additional analysis revealed significant association of α-syn-specific T cell responses with age and lower levodopa equivalent dose. These results confirm the presence of α-syn-reactive T cells in PD and show that they are most abundant immediately after diagnosis of motor PD. These cells may be present years before the diagnosis of motor PD, suggesting avenues of investigation into PD pathogenesis and potential early diagnosis