202 research outputs found
Implementation of novel methods of global and nonsmooth optimization : GANSO programming library
We discuss the implementation of a number of modern methods of global and nonsmooth continuous optimization, based on the ideas of Rubinov, in a programming library GANSO. GANSO implements the derivative-free bundle method, the extended cutting angle method, dynamical system-based optimization and their various combinations and heuristics. We outline the main ideas behind each method, and report on the interfacing with Matlab and Maple packages. <br /
Predicting and controlling the dynamics of infectious diseases
This paper introduces a new optimal control model to describe and control the
dynamics of infectious diseases. In the present model, the average time of
isolation (i.e. hospitalization) of infectious population is the main
time-dependent parameter that defines the spread of infection. All the
preventive measures aim to decrease the average time of isolation under given
constraints
Dynamics of Ebola epidemics in West Africa 2014
This paper investigates the dynamics of Ebola virus transmission in West
Africa during 2014. The reproduction numbers for the total period of epidemic
and for different consequent time intervals are estimated based on a newly
suggested linear model. It contains one major variable - the average time of
infectiousness (time from onset to hospitalization) that is considered as a
parameter for controlling the future dynamics of epidemics.
Numerical implementations are carried out on data collected from three
countries Guinea, Sierra Leone and Liberia as well as the total data collected
worldwide. Predictions are provided by considering different scenarios
involving the average times of infectiousness for the next few months and the
end of the current epidemic is estimated according to each scenario
The Origin of Doping in Quasi-Free Standing Graphene on Silicon Carbide
We explain the robust p-type doping observed for quasi-free standing graphene
on hexagonal silicon carbide by the spontaneous polarization of the substrate.
This mechanism is based on a bulk property of SiC, unavoidable for any
hexagonal polytype of the material and independent of any details of the
interface formation. We show that sign and magnitude of the polarization are in
perfect agreement with the doping level observed in the graphene layer. With
this mechanism, models based on hypothetical acceptor-type defects as they are
discussed so far are obsolete. The n-type doping of epitaxial graphene is
explained conventionally by donor-like states associated with the buffer layer
and its interface to the substrate which overcompensate the polarization
doping.Comment: 10 pages, 1 figur
Accepting a scholarly identity: Gifted students, academic crowd membership, and identification with school
This study examined identification with school among middle school students and its relationship with academic crowd membership, a public expression of oneβs academic orientation. Of the 127 Grade 6 to 8 students in the sample, 55 reported participation in a gifted program; 44% of these gifted students did not claim affiliation with the academic crowd. There was a positive correlation between identification with school and the importance placed on membership for students in the academic crowd, both gifted and nongifted. The California Bully Victimization Scale was used to determine that no group was more likely to have been victimized. Cluster analysis of crowd memberships indicated that gifted students not in the academic crowd had few other crowd memberships, suggesting that middle school may be an important time to encourage a willingness to be viewed by peers as academically oriented through promoting identification with school
Computed tomography data colouring based on photogrammetric images
Nowadays various methods and sensors are available for 3D reconstruction tasks; however, it is still necessary to integrate advantages of different technologies for optimizing the quality 3D models. Computed tomography (CT) is an imaging technique which takes a large number of radiographic measurements from different angles, in order to generate slices of the object, however, without colour information. The aim of this study is to put forward a framework to extract colour information from photogrammetric images for corresponding Computed Tomography (CT) surface data with high precision. The 3D models of the same object from CT and photogrammetry methods are generated respectively, and a transformation matrix is determined to align the extracted CT surface to the photogrammetric point cloud through a coarse-to-fine registration process. The estimated pose information of images to the photogrammetric point clouds, which can be obtained from the standard image alignment procedure, also applies to the aligned CT surface data. For each camera pose, a depth image of CT data is calculated by projecting all the CT points to the image plane. The depth image is in principle should agree with the corresponding photogrammetric image. The points, which cannot be seen from the pose, but are also projected on the depth image, are excluded from the colouring process. This is realized by comparing the range values of neighbouring pixels and finding the corresponding 3D points with larger range values. The same procedure is implemented for all the image poses to obtain the coloured CT surface. Thus, by using photogrammetric images, we achieve a coloured CT dataset with high precision, which combines the advantages from both methods. Rather than simply stitching different data, we deep-dive into the photogrammetric 3D reconstruction process and optimize the CT data with colour information. This process can also provide an initial route and more options for other data fusion processes
Psychological heterogeneity among honors college students
Greater knowledge of the psychology of honors college students will help to inform program administrators, counselors, residence life assistants, and faculty about how they may provide support to those with the greatest need. Via an online survey, personality, perfectionism, and suicidal ideation data were collected from honors college students (N = 410, 73% female). Using latent profile analysis, students were classified by their responses to the Big Five Inventory personality measure into five profiles. Risk factors of high perfectionism and suicidal ideation scores were found in two of the profiles, suggesting students with these personality characteristics may need enhanced psychological support. The largest profile (35% of students) had extraversion scores above the norm, but all other profiles had introverted scores below the norm. Neuroticism scores were also higher than the norm in the introverted profiles, which represented a majority of the honors college students
Coverage in WLAN: Optimization Model and Algorithm
When designing wireless communication systems, it is very important to know the optimum numbers of access points (APs) in order to provide a reliable design. In this paper we describe a mathematical model developed for finding the optimal number and location of APs. A new Global Optimization Algorithm (AGOP) is used to solve the problem. Results obtained demonstrate that the model and software are able to solve optimal coverage problems for design areas with different types of obstacles and number of users
ΠΠΎΠ΄Π΅Π»Ρ ΠΈ ΠΌΠ΅ΡΠΎΠ΄ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΡΡΡΠΊΡΡΡΡ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ Π΄Π»Ρ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΡ
The article investigates the problem of information security of critical information infrastructures. The features of critical objects from the point of view of collecting, processing, storing and transmitting information are analysed. The set of functions performed by the information security system in critical infrastructures and the dependencies between these functions are studied. A model of the security system is proposed and the require ments for this model are defined. At the same time, the set of relations between objects and threats is represented in the form of an object-threat relationship graph, in which an edge connecting the j-th object with the i-th threat exists only when the i-th threat can directly affect the j-th object. To protect objects of critical information infrastructures from possible threats, a set of necessary methods and tools has been introduced into the model of the security system, which converts a two-sided graph into a three-sided one, such as βobject β method β threatβ. Further in the article, the problem of determining the optimal structure of the security system for critical information infrastructure objects is considered. It is assumed here that each threat can affect several objects, and that any object can be affected by more than one threat. The solution of this problem makes it possible to minimize the material costs to implement the methods and tools for protection and minimize damage from a security breach.Β ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π° ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ° ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΡΡ
ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡ. ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈ Π²Π°ΠΆΠ½ΡΡ
ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ² Ρ ΡΠΎΡΠΊΠΈ Π·ΡΠ΅Π½ΠΈΡ ΡΠ±ΠΎΡΠ°, ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ, Ρ
ΡΠ°Π½Π΅Π½ΠΈΡ ΠΈ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠΈ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ. ΠΠ·ΡΡΠ΅Π½Ρ ΡΠΎΠ²ΠΎΠΊΡΠΏΠ½ΠΎΡΡΡ ΡΡΠ½ΠΊΡΠΈΠΉ, Π²ΡΠΏΠΎΠ»Π½ΡΠ΅ΠΌΡΡ
ΡΠΈΡΡΠ΅ΠΌΠΎΠΉ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ Π² ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΠ°Ρ
, ΠΈ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΡΡΠΈΠΌΠΈ ΡΡΠ½ΠΊΡΠΈΡΠΌΠΈ. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ ΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΡ, ΠΏΡΠ΅Π΄ΡΡΠ²Π»ΡΠ΅ΠΌΡΠ΅ ΠΊ Π½Π΅ΠΉ. ΠΠ½ΠΎΠΆΠ΅ΡΡΠ²ΠΎ ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΉ ΠΌΠ΅ΠΆΠ΄Ρ ΠΎΠ±ΡΠ΅ΠΊΡΠ°ΠΌΠΈ ΠΈ ΡΠ³ΡΠΎΠ·Π°ΠΌΠΈ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΎ Π² Π²ΠΈΠ΄Π΅ Π³ΡΠ°ΡΠ° ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΉ Β«ΠΎΠ±ΡΠ΅ΠΊΡ β ΡΠ³ΡΠΎΠ·Π°Β», Π² ΠΊΠΎΡΠΎΡΠΎΠΌ ΡΠ΅Π±ΡΠΎ, ΡΠ²ΡΠ·ΡΠ²Π°ΡΡΠ΅Π΅ j-ΠΉ ΠΎΠ±ΡΠ΅ΠΊΡ Ρ i-ΠΉ ΡΠ³ΡΠΎΠ·ΠΎΠΉ, ΡΡΡΠ΅ΡΡΠ²ΡΠ΅Ρ ΡΠΎΠ»ΡΠΊΠΎ ΡΠΎΠ³Π΄Π°, ΠΊΠΎΠ³Π΄Π° i-Ρ ΡΠ³ΡΠΎΠ·Π° ΠΌΠΎΠΆΠ΅Ρ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΎΠ²Π°ΡΡ Π½Π°ΠΏΡΡΠΌΡΡ Π½Π° j-ΠΉ ΠΎΠ±ΡΠ΅ΠΊΡ. ΠΠ»Ρ Π·Π°ΡΠΈΡΡ ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ² ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΡΡ
ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡ ΠΎΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΡΡ
ΡΠ³ΡΠΎΠ· Π² ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ Π²Π²Π΅Π΄Π΅Π½ΠΎ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ²ΠΎ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΡΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΈ ΡΡΠ΅Π΄ΡΡΠ², ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΡΡΡΠ΅Π΅ Π΄Π²ΡΡ
Π΄ΠΎΠ»ΡΠ½ΡΠΉ Π³ΡΠ°Ρ Π² ΡΡΠ΅Ρ
Π΄ΠΎΠ»ΡΠ½ΡΠΉ, ΡΠΈΠΏΠ° Β«ΠΎΠ±ΡΠ΅ΠΊΡ β ΠΌΠ΅ΡΠΎΠ΄ β ΡΠ³ΡΠΎΠ·Π°Β». Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Π° Π·Π°Π΄Π°ΡΠ° ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΡΡΡΠΊΡΡΡΡ ΡΠΈΡΡΠ΅ΠΌΡ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ² ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΡ, ΡΠ΅ΡΠ΅Π½ΠΈΠ΅ ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ ΡΠ²Π΅ΡΡΠΈ ΠΊ ΠΌΠΈΠ½ΠΈΠΌΡΠΌΡ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΡΠ΅ Π·Π°ΡΡΠ°ΡΡ Π½Π° ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΡ ΡΡΠ΅Π΄ΡΡΠ² Π·Π°ΡΠΈΡΡ ΠΈ ΡΡΠ΅ΡΠ± ΠΎΡ Π½Π°ΡΡΡΠ΅Π½ΠΈΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΠΈ.
Detecting K-complexes for sleep stage identification using nonsmooth optimisation
The process of sleep stage identification is a labour-intensive task that involves the specialized interpretation of the polysomnographic signals captured from a patient’s overnight sleep session. Automating this task has proven to be challenging for data mining algorithms because of noise, complexity and the extreme size of data. In this paper we apply nonsmooth optimization to extract key features that lead to better accuracy. We develop a specific procedure for identifying K-complexes, a special type of brain wave crucial for distinguishing sleep stages. The procedure contains two steps. We first extract “easily classified” K-complexes, and then apply nonsmooth optimization methods to extract features from the remaining data and refine the results from the first step. Numerical experiments show that this procedure is efficient for detecting K-complexes. It is also found that most classification methods perform significantly better on the extracted features
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