cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
QoE Assessment Model for Addis Ababa LTE Video Streaming Service Using Machine Learning Techniques
Creators: name: Addisu, Shiferaw
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020

description: In today's connected world, the availability of fast Internet access and penetration of smart-phones has created an opportunity for the emerging of new telecom services. Similarly, in Ethiopia, the improvement of technology brought a change from the traditional services to more advanced communication like video streaming service. To ensure whether the customers have satisfied for a given service or not, capturing user Quality of Experience (QoE) is important. Traditionally, Internet Service Providers (ISP)s monitor the network performance by collecting network key performance indicators without involving users' perception. However, user-perceived QoE estimation is multidimensional, which is affected by different influencing factors. So, estimating user-centric QoE based on Network-level QoS (NQoS) remains challenging tasks for ISPs. Yet, QoE assessment model for video streaming services that map Quality of Service (QoS) to QoE concerning users' perception has not been performed in Ethiopia. This thesis proposes video streaming QoE assessment models using machine learning techniques to estimate user-perceived experience in the Long-Term Evolution (LTE) network. The model predicts perceived QoE in a Mean Opinion Score (MOS), by evaluating NQoS, Application-level QoS (AQoS) and contextually formulated survey questionnaire. The models take NQoS metrics such as upload bit rate and download bit rate in Megabits Per Second (Mb/s), latency and jitter in milliseconds (ms), and packet loss in percentage. Content-type and resolution also considered from the application level. Contrary to existing models for QoE prediction, the proposed model gives a good estimation of the perceived quality with a minimum Mean Squared Error (MSE) of 7.74%; and Pearson and Spearman correlations of 97.94% and 97.43%, corresponding to the measured QoE. The result obtained from the model shows that the average MOS value is 2.79, which is below the recommended one. Accordingly, the proposed model allows ISP to monitor the perceived QoE level accurately.
Relativistic description of dense matter equation of state and compatibility with neutron star observables: a Bayesian approach
Creators: name: Malik, Tuhin
name: Ferreira, Márcio
name: Agrawal, B. K.
name: Providência, Constança
Publisher: name: arXiv
Year: 2022
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The general behavior of the nuclear equation of state (EOS), relevant for the description of neutron stars (NS), is studied within a Bayesian approach applied to a set of models based on a density dependent relativistic mean field description of nuclear matter. The EOS is subjected to a minimal number of constraints based on nuclear saturation properties and the low density pure neutron matter EOS obtained from a precise next-to-next-to-next-to-leading order (N$^{3}$LO) calculation in chiral effective field theory ($χ$EFT). The posterior distributions of the model parameters obtained under these minimal constraints are employed to construct the distributions of various nuclear matter properties and NS properties such as radii, tidal deformabilites, central energy densities and speeds of sound etc. We found that 90% confidence interval (CI) for allowed NS mass - radius relationship and tidal deformabilites are compatible with GW170817 and recent NICER observations, without invoking the exotic degrees of freedom. A central speed-of-sound of the order of $\sqrt{2/3}$ $c$ is obtained. The maximum neutron star mass allowed by the model is 2.5 $M_\odot$.
description: 20 pages, 11 figures (Accepted in ApJ)
Limits on sequential sharing of nonlocal advantage of quantum coherence
Creators: name: Hu, Ming-Liang
name: Wang, Jia-Ru
name: Fan, Heng
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Sequential sharing of nonlocal correlation is inherently related to its application. We address the question as to how many observers can share the nonlocal advantage of quantum coherence (NAQC) in a $(d\times d)$-dimensional state, where $d$ is a prime or a power of a prime. We first analyze the trade-off between disturbance and information gain of the general $d$-dimensional unsharp measurements. Then in a scenario where multiple Alices perform unsharp measurements on one party of the state sequentially and independently and a single Bob measures coherence of the conditional states on the other party, we show that at most one Alice can demonstrate NAQC with Bob. This limit holds even when considering the weak measurements with optimal pointer states. These results may shed light on the interplay between nonlocal correlations and quantum measurements on high-dimensional systems and the hierarchy of different quantum correlations.
description: 8 pages, 4 figures
Efficient Simulation of Quantum Many-body Thermodynamics by Tailoring Zero-temperature Tensor Network
Creators: name: Wang, Ding-Zu
name: Zhang, Guo-Feng
name: Lewenstein, Maciej
name: Ran, Shi-Ju
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Numerical annealing and renormalization group have conceived various successful approaches to study the thermodynamics of strongly-correlated systems where perturbation or expansion theories fail to work. As the process of lowering the temperatures is usually involved in different manners, these approaches in general become much less efficient or accurate at the low temperatures. In this work, we propose to access the finite-temperature properties from the tensor network (TN) representing the zero-temperature partition function. We propose to "scissor" a finite part from such an infinite-size TN, and "stitch" it to possess the periodic boundary condition along the imaginary-time direction. We dub this approach as TN tailoring. Exceptional accuracy is achieved with a fine-tune process, surpassing the previous methods including the linearized tensor renormalization group [Phys. Rev. Lett. 106, 127202 (2011)], continuous matrix product operator [Phys. Rev. Lett. 125, 170604 (2020)], and etc. High efficiency is demonstrated, where the time cost is nearly independent of the target temperature including the extremely-low temperatures. The proposed idea can be extended to higher-dimensional systems of bosons and fermions.
description: 5 pages, 4 figures
Alternative Food Networks e 15-Minute City. Ripensare la distribuzione del cibo per favorire una trasformazione urbana sostenibile
Creators: name: Bruno, Riccardo Giovanni
Publisher: name: Semestrale di studi e ricerche di geografia
Year: 2024

description: Questo studio si concentra sul modello 15-Minute City (FMC) come approccio di sviluppo urbano utile a garantire maggiore vivibilità nelle città indipendentemente dal quartiere di appartenenza. Per comprendere quali percorsi possono essere intrapresi per promuovere una partecipazione degli abitanti dei diversi quartieri nei processi decisionali relativi all’implementazione della FMC, questo studio discute il ruolo degli AFNs come ambiti utili a favorire sensibilizzazione e aggregazione nei quartieri. Dopo una rassegna della letteratura circa la correlazione tra AFNs e FMC, si svolge una ricerca empirica volta ad indagare la percezione di alcuni cittadini. Attraverso una serie di interviste semi-strutturate, si discute il ruolo degli AFNs nello stimolare l'implementazione della FMC; l’indagine è realizzata in due quartieri della città di Torino, Barriera di Milano e Crocetta.
description: Semestrale di studi e ricerche di geografia, N. 1 (2024)
title: Irrational, unprofessional, radical?: Towards a differentiated perspective on age in international law and politics scholarship
Creators: name: Kunz, Raffaela
name: Holzscheiter, Anna
Publisher: name: Fachinformationsdienst für internationale und interdisziplinäre Rechtsforschung
Year: 2020
Subjects: subject: 341

description: Völkerrechtsblog
QoE Model for Addis Ababa LTE Web Browsing Service Using Neural Network Approach
Creators: name: Dereje, Solomon
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: In order to address the customer's satisfaction, mobile operators try to find out what the customer needs and what quality makes the customer satisfied. The customer satisfaction can be measured or estimated by Quality of Experience (QoE) measurement. Its estimation and measurement is important to identify the network problems, to understand causes and contributing factors. Web browsing is one of the widely used application on Long Term Evolution (LTE) networks. Therefore, it is essential for service providers to ensure a better QoE on web browsing service. Web QoE can measure the user satisfaction by subjective or objective measurement. Subjective test suffers from some drawbacks, such as it has high cost in terms of time, money, and manual effort and also cannot be used for real-time QoE evaluation. In Ethiopia only subjective measurement is used, to know the level of customer satisfaction. Due to that, the company is exposed for high expenses and also can not perform the real time measurement of QoE. To overcome the problem on subjective test, this thesis developed a web browsing QoE model, using Neural Network algorithm that is implemented in matlab software. The model takes the following QoS metrics as input parameters: page response delay, page content browsing delay and page download throughput. The model map these metrics to QoE interms of Mean Opinion Score (MOS). The model performed an estimation of QoE with a Mean Square Error (MSE) of 0.002 and correlation of 97.2%, relatively to the target QoE. As the result indicates, the estimated and measured QoE values are highly correlated. And the error between them is very low. So, this model can be used for estimating the web browsing QoE for the mobile operators, to get objective measurement advantages. Also, it can be used for operators to identify the network factors that most influence the web browsing QoE.
Dr.Jit: A Just-In-Time Compiler for Differentiable Rendering
Creators: name: Jakob, Wenzel
name: Speierer, Sébastien
name: Roussel, Nicolas
name: Vicini, Delio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Dr.Jit is a new just-in-time compiler for physically based rendering and its derivative. Dr.Jit expedites research on these topics in two ways: first, it traces high-level simulation code (e.g., written in Python) and aggressively simplifies and specializes the resulting program representation, producing data-parallel kernels with state-of-the-art performance on CPUs and GPUs. Second, it simplifies the development of differentiable rendering algorithms. Efficient methods in this area turn the derivative of a simulation into a simulation of the derivative. Dr.Jit provides fine-grained control over the process of automatic differentiation to help with this transformation. Specialization is particularly helpful in the context of differentiation, since large parts of the simulation ultimately do not influence the computed gradients. Dr.Jit tracks data dependencies globally to find and remove redundant computation.
description: To appear at SIGGRAPH 2022
Memorie contese di guerra e proposte di valorizzazione from below. Il caso del territorio del Frusinate attraversato dalla Linea Gustav
Creators: name: Giantomasso, Camilla
Publisher: name: Semestrale di studi e ricerche di geografia
Year: 2024

description: Il contributo intende fare luce su una vicenda a lungo trascurata dalla storiografia italiana e internazionale, ovvero quella delle “marocchinate”, termine usato per indicare gli stupri di massa avvenuti durante la Seconda guerra mondiale nel Basso Lazio ad opera del contingente coloniale francese impegnato nella campagna di sfondamento della linea Gustav, una delle linee di fortificazione costruita dalle truppe tedesche per frenare l’avanzata degli Alleati. Per troppo tempo questa tragedia è stata racchiusa nei sotterranei della storia, in parte anche per l’estrema difficoltà di una sua rielaborazione all’interno di una società patriarcale e coloniale. In tale quadro, gli obiettivi sono duplici: da un lato riaccendere i riflettori su tali episodi e contribuire al dibattito critico sui processi di memorializzazione e di patrimonializzazione from below, dall’altro capire se e come la memoria possa fungere da parametro per l’azione territoriale.
description: Semestrale di studi e ricerche di geografia, N. 1 (2024)
Optimized Backhaul Planning for the Case of Small Cell Deployment in Addis Ababa Region of ethio telecom
Creators: name: Mulugeta, Mihret
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020

description: Operators are deploying small cells to complement their macro cells to increase the coverage and capacity of their mobile networks. Backhauling the small cells traffic to the core network is a challenge to operators as they are usually placed in difficult to access locations. To overcome this challenge, wireless solutions have been proposed as a costeffective alternative to wired solutions. There are, however, many wireless technologies to realize this: point-to-point/point-to-multipoint, line-of-sight/non-line-of-sight (NLOS) and millimeter wave/microwave bands. This research studies practical wireless configurations of this technologies, and proposes a planning method an operator can determine which technology to use on each link of the small cell backhaul network so that the total cost of ownership (TCO) is minimized. To this end, a mixed integer linear programming (MILP) is formulated with a range of constraints for wireless technologies and backhaul requirements. To demonstrate the effectiveness of the method, the MILP was used to plan a small cell backhaul network for different scenarios, in a relatively built up area of Addis Ababa. The scenarios were created based on different small cell demands, and on whether NLOS links are allowed in the network. The path loss values were predicted by ray tracing to determine the feasibility of a link configuration of each technology between nodes of the backhaul network. The results showed the reduction of TCO by inclusion of more technologies as can be seen with the need for more new aggregation nodes when NLOS was not considered. By accepting an optimality gap of 5 %, the computation time was also reduced to less than two hours which is acceptable for the purpose of planning. Using this method, an operator can plan a cost-effective backhaul from available practical wireless technologies.
Ateuchus guatemalensis  1887
Creators: name: Kohlmann, Bert
name: Vaz-de-Mello, Fernando Z.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Ateuchus
Ateuchus guatemalensis

description: Ateuchus guatemalensis (Bates), 1887
This species has been recorded from Chiapas, Guatemala and Honduras. It is here recorded for the first time from Nicaragua.
Nicaragua: Jinotega: Cerro Kilambe, Camp 5, Las Torres, UTM–16P–1500283–0639500, 1200 m, 23/ 30-IV-2001, col. J. Sunyer y B. Hernández (5 specimens at CEMT); Masaya: Las Flores, VII–1998, col. J. Téllez (1 specimen at CEMT).
 Ateuchus hornai (Balthasar, 1939), new combination (valid species)
(Fig. 5)
 This species was previously considered a synonym of A. illaesum based on the original description, since the holotype was not available for study at the time (Kohlmann, 1984). The examination of the female holotype found in the Natural History Museum in Prague, Czech Republic (Bezdek and Hajek, 2011), allowed us to consider it a valid species, distinguishable by the characters in the key presented herein. We suspect the type locality (Necaxa, Puebla, México) to be wrong, and we hope that a male will be collected in order to prepare a more thorough description of this interesting species.
description: Published as part of Kohlmann, Bert & Vaz-de-Mello, Fernando Z., 2018, A new key for the species of Ateuchus Weber (Coleoptera: Scarabaeidae: Scarabaeinae) occurring in Mexico, with a description of the first North American inquiline species from a rodent burrow (Rodentia: Geomydae) and new distribution records, pp. 131-134 in Revista Brasileira de Entomologia 62 (2) on page 134, DOI: 10.1016/j.rbe.2018.01.002, http://zenodo.org/record/13198486
Scalar perturbation of gravitating double-kink solutions
Creators: name: Feng, Jun
name: Zhong, Yuan
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this letter, a two-dimensional (2D) gravity-scalar model is studied. This model supports interesting double-kink solutions, and the corresponding metric solutions can be derived analytically. Depending on a tunable parameter $c$, the metric can be symmetric or asymmetric. The Schrödinger-like equation for normal modes of the physical linear perturbation is derived. As $c$ varies, the effective potential can have one or two singular barriers. If $c$ is larger than a critical value, the zero mode will be normalizable, despite of the appearance of a strong repulsive singularity. The double-kink solution is always stable against linear perturbations.
description: 6 pages, 4 figures, final version published by EPL
ecurrent Neural Network-based Base Transceiver Station Power System Failure Prediction
Creators: name: Tewodros, Kibatu
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: Global network infrastructures are increasing with the development of new technologies and growth in Internet traffic. As network infrastructures increases, maintaining and monitoring them will become very challenging since thousands of alarms are generated every day. Clearing those alarms by corrective maintenance activities require considerable effort and resources (car, labor, and budget). In mobile networks, a Base Transceiver Station (BTS) is one key infrastructure element performing the task of connecting customer equipment with the cellular network. BTS services may be interrupted due to transmission, optical fiber cut, power system failure, natural disaster or many more. In the case of Ethio Telecom (ET), the sole telecom service provider in Ethiopia, power system failure takes the biggest share for interruption of BTS services. Minimizing power system failure will reduce downtime of the BTS thereby, guarantee customer satisfaction and maximize revenue. Recently, machine learning algorithms are used to predict failure in various areas like power distribution, hydropower generation plants, solar power generation plants, high voltage transmission grid and many more. This thesis investigates predicting BTSs power system failure using a recurrent neural network (RNN) types namely, long short term memory (LSTM) and gated recurrent unit (GRU) with linear and sigmoid activation function applied for the output. In parallel, the prediction performance of LSTM and GRU has been compared. Data collected from five BTS sites for twenty weeks of observations are used to train and test the model. The data are prepared with two different data arrangements, which are a single site and multiple sites. The relevance of using different data size is, to check the impact of increasing data size with different arrangements on the prediction results. Mean squared error (MSE) and number of epoch are used to evaluate the performance of the models with different configurations. Based on the results found, GRU using sigmoid activation function with feature reduction achieves better performance than LSTM. In addition, both LSTM and GRU can be used for predicting BTS power system failure.
Is gravitational collapse possible in $f(R)$ gravity?
Creators: name: Casado-Turrión, Adrián
name: de la Cruz-Dombriz, Álvaro
name: Dobado, Antonio
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Gravitational collapse is still poorly understood in the context of $f(R)$ theories of gravity, since the Oppenheimer-Snyder model is incompatible with their junction conditions. In this work, we will present a systematic approach to the problem. Starting with a thorough analysis of how the Oppenheimer-Snyder construction should be generalised to fit within metric $f(R)$ gravity, we shall subsequently proceed to explore the existence of novel exterior solutions compatible with physically viable interiors. Our formalism has allowed us to show that some paradigmatic vacuum metrics cannot represent spacetime outside a collapsing dust star in metric $f(R)$ gravity. Moreover, using the junction conditions, we have found a novel vacuole solution of a large class of $f(R)$ models, whose exterior spacetime is documented here for the first time in the literature as well. Finally, we also report the previously unnoticed fact that the Oppenheimer-Snyder model of gravitational collapse is incompatible with the Palatini formulation of $f(R)$ gravity.
description: 18 pages, 0 figures; minor typos corrected, version published in Phys. Rev. D 105 084060
Performance Analysis of Spectrum Scenarios for Outdoor LTE Small Cell Planning: The Case of Addis Ababa, Ethiopia
Creators: name: Bezuayehu, Zerihun
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: Due to the increasing penetration of smart devices and data intensive applications, mobile network operators are experiencing exponential data growth. In effect, network capacity limitation that leads to performance degradation is observed. To address this limitation, deployment of different types of small cells under umbrella macro network that results Heterogeneous Networks (HetNets) has been considered as one key capacity enhancement approach. In the introduction of HetNets, operator decision on spectrum allocation scheme significantly determines network performance. The Ethiopian sole telecom operator, ethio telecom, has recently started the path to operate and manage HetNets by deploying small cells within its existing macro network. Nevertheless, there is no thorough performance study on potential spectrum scenarios considering Ethiopia's network environment so that an informed spectrum usage strategy is formulated. Spectrum scenarios can be cochannel, where small cells apply same frequency band used by macro cells, dedicated, where they apply different frequency bands or a hybrid of cochannel and dedicated. In this thesis, performance analysis is carried out for the spectrum scenarios formulated using 1800MHz and 2600MHz bands from network planning perspective while considering realistic network environment for selected area of Addis Ababa, Ethiopia. Multiobjective optimization based on Genetic Algorithm is applied for network planning. Network simulation is implemented using MatLab while propagation computation is performed using WinProp. Performance results show that, allocating dedicated 20MHz band for small cell in 2600MHz band provides better aggregate capacity than allocating dedicated same amount of band in 1800MHz. For instance, dedicated 20MHz in 2600MHz band achieves 0.036Gbps per square km more capacity than in 1800MHz band for around three small cells per sector optimal deployment. On the other hand, dedicated 20MHz in 1800MHz achieves 2.3% less user outage rate than dedicated same amount of band in 2600MHz with around three small cells per sector optimal deployment. With regards to small cell distribution, planning results show that outdoor small cell deployment is needed more in locations other than main street.
Synthesis, Characterization and Ab Initio Calculations of Aminophosphine Derived From 4-Benzylpiperidine, its Chalcogenide Derivatives and Molybdenum(0) Complex
Creators: name: Sarıöz, Özlem
name: Çağrı Çırak
name: Muradoğlu, Vefa
name: Öznergiz, Sena
Publisher: name: Taylor & Francis
Year: 2014
Subjects: Uncategorised

description: Functionalized monoaminophosphine PPh2NC5H9CH2C6H5 has been synthesized by treating Ph2PCl with 4-benzylpiperidine. The ligand reacts with aqueous hydrogen peroxide, elemental sulfur or selenium to give the corresponding chalcogenides in good yield. The molybdenum complex of the aminophosphine has been obtained. All of the new compounds were obtained in good yields and were characterized by IR, NMR, elemental analysis. Theoretical calculations were carried out by using the Hartree-Fock and density functional methods with the 6-31G(d) basis set. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional tables and figures.]
Optimized Line Amplifier Placement for Energy Saving: a Case Study of ethio telecom Optical Backbone Network
Creators: name: Aselef, Teka
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020

description: In recent years, traffic volume is increasing tremendously. In line with this increment, telecom operators expand their network infrastructure. This increases power consumption of the network. Especially in a backbone network, where power consumption is dependent on traffic volume, the increase in power consumption is becoming critical. Researchers are made efforts dedicated to reduce unnecessary energy waste in backbone networks using physical topology optimization for highly connected networks, but this optimization is not feasible for low connected networks like ethio telecom. In addition, line amplifiers are placed at regular interval of 80km without considering physical and economic restrictions. In practice, amplifier placement is commonly implemented by operators to guarantee a signal quality considering placement location with availability supply power, shelter, and physical security with the expense of high power consumption. Current ethio telecom line amplifiers are placed at span length ranging from 25 to 120km considering these physical and economic restrictions; due to this, ethio telecom is subjected to high power consumption in line amplifiers. In this thesis, optimized line amplifier placement, which takes power consumption and physical and economic restrictions in to account is investigated. Mixed Integer Linear Programming (MILP) formulation which takes span length and input power level constraint is proposed. The proposed power-saving approach is evaluated considering ethio-telecom North circle optical backbone network topology. MATLAB is used to assign optimum placement location. The result is compared with theoretical standard (80km spacing) and the practical (ethio telecom current deployment scenario) using number of amplification sites and power saving performance. The comparison results show that amplifier site placement using the new approach can minimize the number of amplification sites by 9 from the theoretical approach and by 5 from the existing configuration and a 2% power saving can be achieved in the case study network portion.
Solution of the Continuous Time Bilinear Quadratic Regulator Problem by Krotov's Method
Creators: name: Halperin, Ido
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: This work contributes to the field of optimal control of bilinear systems. It concerns a continuous time, finite dimensional, bilinear state equation with a quadratic performance index to be minimized. The state equation is non-autonomous and comprises a deterministic, a-priori known excitation. The control trajectory is constrained to an admissible set without a specific structure. The performance index is a functional, quadratic in the state variables and control signals. Krotov's method is used for solving this problem by means of an improving sequence. To this end, the required sequence of an improving functions is formulated. Finally, the solution is encapsulated in an algorithm form and a numerical example of structural control problem is provided.
description: \copyright 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works
Theoretical Analysis of SIRVVD Model to Provide Insight on the Target Rate of COVID-19/SARS-CoV-2 Vaccination in Japan
Creators: name: Omae, Yuto
name: Sasaki, Makoto
name: Toyotani, Jun
name: Hara, Kazuyuki
name: Takahashi, Hirotaka
Publisher: name: arXiv
Year: 2022
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Dynamical Systems (math.DS)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Biological sciences
subject: FOS: Mathematics

description: The effectiveness of the first and second dose vaccinations are different for COVID-19; therefore, a susceptible-infected-recovered-vaccination1-vaccination2-death (SIRVVD) model that can represent the states of the first and second vaccination doses has been proposed. By the previous study, we can carry out simulating the spread of infectious disease considering the effects of the first and second doses of the vaccination based on the SIRVVD model. However, theoretical analysis of the SIRVVD Model is insufficient. Therefore, we obtained an analytical expression of the infectious number, by treating the numbers of susceptible persons and vaccinated persons as parameters. We used the solution to determine the target rate of the vaccination for decreasing the infection numbers of the COVID-19 Delta variant (B.1.617) in Japan. Further, we investigated the target vaccination rates for cases with strong or weak variants by comparison with the COVID-19 Delta variant (B.1.617). This study contributes to the mathematical development of the SIRVVD model and provides insight into the target rate of the vaccination to decrease the number of infections.
description: 9 pages, 6 figures
Presentazione dei risultati del 2° Rapporto sulla Scuola e l’Università dell’Eurispes (Roma, 8 febbraio 2024)
Creators: name: Pallottino, Carlotta Anna
Publisher: name: Semestrale di studi e ricerche di geografia
Year: 2024

description: L’8 Febbraio 2024, presso la Biblioteca Nazionale Centrale a Roma, il presidente dell'Eurispes Gian Maria Fara e il Mario Caligiuri, Osservatorio sulle Politiche Educative dell'Eurispes, hanno presentato il 2° Rapporto Nazionale sulla Scuola e l’Università a cura dell’Eurispes, edito da Giunti Scuola nel 2023 a 20 anni dalla precedente edizione.
description: Semestrale di studi e ricerche di geografia, N. 1 (2024)
Synthesis, Crystal Structure, and Characterization of A New Adduct Bis-(2-Amino-3-Benzyloxypyridinium) Selenate Monohydrate [C12H13N2O]2SeO4.H2O
Creators: name: Soukrata, Sami
name: Belhouchet, Mohamed
name: Joen Josep Suñol
name: Mhiri, Tahar
Publisher: name: Taylor & Francis
Year: 2014
Subjects: Uncategorized

description: A new adduct bis-(2-amino-3-benzyloxypyridinium) selenate monohydrate, [C12H13N2O]2SeO4.H2O, has been synthesized by slow evaporation at room temperature using 2-amino-3-benzyloxypyridine as the structure-directing agent. The structure, determined by single-crystal X-ray diffraction at 298 K, can be described as organic-inorganic tunnels with different forms built by infinite inorganic chains parallel to the c axis and connected to the organic cations. In this atomic arrangement, hydrogen bonds and van der Waals interactions between the different species play an important role in the tri-dimensional network cohesion. Solid-state 13C and 77Se MAS NMR spectroscopy results are in agreement with the X-ray structure. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.]
Semiclassical approach to $S$ matrix energy correlations and time delay in chaotic systems
Creators: name: Novaes, Marcel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The $M$-dimensional scattering matrix $S(E)$ which connects incoming to outgoing waves in a chaotic systyem is always unitary, but shows complicated dependence on the energy. This is partly encoded in correlators constructed from traces of powers of $S(E+ε)S^\dagger(E-ε)$, averaged over $E$, and by the statistical properties of the time delay operator, $Q(E)=-i\hbar S^\dagger dS/dE$. Using a semiclassical approach for systems with broken time reversal symmetry, we derive two kind of expressions for the energy correlators: one as a power series in $1/M$ whose coefficients are rational functions of $ε$, and another as a power series in $ε$ whose coefficients are rational functions of $M$. From the latter we extract an explicit formula for $\rm{Tr}(Q^n)$ which is valid for all $n$ and is in agreement with random matrix theory predictions.
description: 6 pages
Dynamical double black holes and their host cluster properties
Creators: name: Chattopadhyay, Debatri
name: Hurley, Jarrod
name: Stevenson, Simon
name: Raidani, Arihant
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate the relationship between the global properties of star clusters and their double black hole (DBH) populations. We use the code {\tt NBODY6} to evolve a suite of star cluster models with an initial mass of $\mathcal{O}(10^4)$M$_\odot$ and varying initial parameters. We conclude that cluster metallicity plays the most significant role in determining the lifespan of a cluster, while the initial half-mass radius is dominant in setting the rate of BH exchange interactions in the central cluster regions. We find that the mass of interacting BHs, rather than how frequently their interactions with other BHs occur, is more crucial in the thermal expansion and eventual evaporation of the cluster. We formulate a novel approach to easily quantify the degree of BH-BH dynamical activity in each model. We report 12 in-cluster and three out-of-cluster (after ejection from the cluster) DBH mergers, of different types (inspiral, eccentric, hierarchical) across the ten $N$-body models presented. Our DBH merger efficiency is 3--4$\times10^{-5}$ mergers per M$_\odot$. We note the cluster initial density plays the most crucial role in determining the number of DBH mergers, with the potential presence of a transitional density point (between 1.2-3.8$\times10^3$M$_\odot$/pc$^3$) below which the number of in-cluster mergers increases with cluster density and above which the increased stellar density acts to prevent in-cluster BH mergers. The importance of the history of dynamical interactions within the cluster in setting up the pathways to ejected DBH mergers is also discussed. Our findings show a broad match with observed LIGO-Virgo DBH mergers.
description: Submitted to MNRAS, 30 pages
Synthesis of New Aza Thia Crowns Bearing 2,2′-Diaminodiphenyl Disulfide
Creators: name: Esmael Rostami
name: Masume Zangooei
name: Marziyh Ghaedi
Publisher: name: Taylor & Francis
Year: 2014
Subjects: Uncategorized

description: New aza thia crowns were prepared from the reaction of 2,2′-diaminodiphenyl disulfide and diacids or diacid chlorides. Diacids are malonic acid, adipic acid, sebacic acid, and 2,2′-thiodiacetic acid and diacid dichlorides are malonyl chloride, adipoyl chloride, sebacoyl chloride, and 2,2′-thiodiacetyl chloride. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]
Statistical Modeling of Internet Traffic FlowLength and Flow Size
Creators: name: Shemelis, Tadesse
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: The growth of internet traffic forces telecom service providers to invest in new infrastructure and/or expanding the network to achieve the desired Quality of Service (QoS) and cope up the network congestion. But several techniques available for granting QoS and network congestion. The first step is to understand the network performance. Network performance needs accurate traffic modeling that has the potential to improve desired QoS, allocating the network resources (i.e. bandwidth). This thesis presents a statistical model of the internet traffic applications by their random nature of flow-length and flow-size. Wireshark network monitoring and analysis tool is used to collect internet traffic data from the ethio telecom core switch and generating experimental internet traffic data in controlled environment. The experimental data are used to train and test the machine learning model that helps to identify the internet applications. Firstly, identifying internet traffic applications using machine learning classification techniques. Secondly, statistical methods are used to fit the Cumulative Distribution Function (CDF) and select the parameters that best fitted in both flow-length and flow-size for identified applications. Finally, deliver statistical model to each applications and corresponding parameters. Recently internet traffic modeling is applicable in capacity planning for traffic engineering, anomaly detection and performance analysis are some of them. Based on the result found the Log-normal distribution is best fitted to flow-length and flow size for three applications and Weibull distribution is for SSH application in both flow length and flow size.
Synthesis, Characterization, Thermal, and Antibacterial Studies of Organotin(Iv) Complexes of Indole-3-Butyric Acid and Indole-3-Propionic Acid
Creators: name: Chilwal, Asha
name: Malhotra, Priti
name: A. K. Narula
Publisher: name: Taylor & Francis
Year: 2014
Subjects: Uncategorized

description: Six organotin(IV) complexes of type Me2SnL2, Bu2SnL2, and Ph3SnL [where L = indole-3-butyric acid (1, 2 and 3) or indole-3-propionic acid (4, 5 and 6)] have been synthesized by the reactions of the corresponding diorganotin(IV) oxide and triphenyltin(IV) hydroxide with respective indole-3-butyric acid (IBH) or indole-3-propionic acid (IPH) in the desired molar ratios of 1:2/1:1. All of the compounds have been characterized by elemental analysis, IR, 1H NMR, 13C NMR, and 119Sn NMR spectroscopy. Thermal studies of all synthesized complexes have been carried out using thermogravimetry (TG) technique under a nitrogen atmosphere. The thermal decompositions for compounds Me2SnL2 and Bu2SnL2 occurred in two steps, whereas in compounds Ph3SnL, it exhibited as three steps decomposition and resulted into the formation of pure SnO2. The complexes were also screened against three gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus) and three gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) bacteria using minimum inhibition concentration (MIC) method, and all of these complexes showed significant antibacterial activity. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]
title: Dealing with marine debris the ASEAN way: A critical analysis of the ASEAN Framework of Action on Marine Debris and its impact
Creators: name: Goyal, Shubhi
name: Mahaseth, Harsh
Publisher: name: Fachinformationsdienst für internationale und interdisziplinäre Rechtsforschung
Year: 2020
Subjects: subject: 341

description: Völkerrechtsblog
Lo studio oceanografico: l’impegno nelle Università italiane
Creators: name: Romagnoli, Luca
Publisher: name: Semestrale di studi e ricerche di geografia
Year: 2024

description: Come noto, le Nazioni Unite hanno dichiarato il Decennio delle Scienze del mare per lo sviluppo sostenibile 2021-2030 , nell’assunzione che il “Pianeta blu” (considerato il ruolo esiziale dell’oceano, oltre che la sua vastità rispetto alle terre emerse), sia l’unica possibilità di assicurare un futuro sostenibile all’umanità. Scopo del “decennio” è non solo sensibilizzare l’opinione pubblica, ma anche favorire lo sviluppo di studi e soluzioni scientifiche.
description: Semestrale di studi e ricerche di geografia, N. 1 (2024)
Low-Temperature Thermal Conductivity of CeRh$_{2}$As$_{2}$
Creators: name: Onishi, Seita
name: Stockert, Ulrike
name: Khim, Seunghyun
name: Banda, Jacintha
name: Brando, Manuel
name: Hassinger, Elena
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: CeRh$_2$As$_2$ is a rare unconventional superconductor ($T_c=0.26$ K) characterized by two adjacent superconducting phases for a magnetic field $H \parallel c$-axis of the tetragonal crystal structure. Antiferromagnetic order, quadrupole-density-wave order ($T_0 = 0.4$ K) and the proximity of this material to a quantum-critical point have also been reported: The coexistence of these phenomena with superconductivity is currently under discussion. Here, we present thermal conductivity and electrical resistivity measurements on a single crystal of CeRh$_2$As$_2$ between 60 mK and 200 K and in magnetic fields ($H \parallel c$) up to 8 T. Our measurements at low $T$ verify the Wiedemann-Franz law within the error bars. The $T$ dependence of the thermal conductivity $κ(T)$ shows a pronounced drop below $T_c$ which is also field dependent and thus interpreted as the signature of superconductivity. However, the large residual resistivity and the lack of sharp anomalies in $κ(T)$ at the expected transition temperatures clearly indicate that samples of much higher purity are required to gain more information about the superconducting gap structure.
description: 11 pages, 3 figures
Machine Learning Based QoE Estimation Model for Video Streaming over UMTS Network
Creators: name: Digis, Weldu
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020

description: The advent of data-intensive services needs quality Internet services. This in turn, makes Quality of Experience (QoE) gain prominent recognition in the telecommunications industry. Ethio telecom uses network Quality of Service (QoS) monitoring data obtained from Network Management Systems (NMS) tools to comprehend its network performances. However, as QoS measurement refers to network performances, this method does not generally give QoE data as perceived by the user. Therefore, QoE estimation models are proposed as solutions in the literature, recently. This study focuses on developing QoE estimation models using QoS features of round-trip time (RTT), jitter, loss rate (LR) and throughput, and QoE scores collected using Application for prediCting QUality of experience at Interne Access (ACQUA)-based crowdsourcing in Universal Mobile Telecommunication Systems (UMTS) networks in a real-time basis. Data preparations techniques such as data cleaning and dataset imbalance corrections have been applied to the collected datasets. Machine Learning (ML) algorithms of Arti cial Neural Network (ANN), KNearest Neighbor (KNN) and Random Forest (RF) are selected based on their suitability for multilabel problems. After training these models developed, they are evaluated using commonly used performance metrics such as accuracy, Root Mean Square Error (RMSE) and Receiver Operating Characteristics (ROC). Experimentation results exhibit that RF with an accuracy of 98.39%, is the best model while KNN and ANN achieve 87.47% and 77.59% overall accuracy, respectively. As a conclusion, all three models achieve acceptable performances. As a conclusion, our QoE estimation models if implemented can help Telecommunications Service Providers (TSP) in estimating user QoE in real-time.
A Comprehensive Review of Computer Vision in Sports: Open Issues, Future Trends and Research Directions
Creators: name: Naik, Banoth Thulasya
name: Hashmi, Mohammad Farukh
name: Bokde, Neeraj Dhanraj
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Recent developments in video analysis of sports and computer vision techniques have achieved significant improvements to enable a variety of critical operations. To provide enhanced information, such as detailed complex analysis in sports like soccer, basketball, cricket, badminton, etc., studies have focused mainly on computer vision techniques employed to carry out different tasks. This paper presents a comprehensive review of sports video analysis for various applications high-level analysis such as detection and classification of players, tracking player or ball in sports and predicting the trajectories of player or ball, recognizing the teams strategies, classifying various events in sports. The paper further discusses published works in a variety of application-specific tasks related to sports and the present researchers views regarding them. Since there is a wide research scope in sports for deploying computer vision techniques in various sports, some of the publicly available datasets related to a particular sport have been provided. This work reviews a detailed discussion on some of the artificial intelligence(AI)applications in sports vision, GPU-based work stations, and embedded platforms. Finally, this review identifies the research directions, probable challenges, and future trends in the area of visual recognition in sports.
Users Throughput Enhancement of LTE Network using Carrier Aggregation for Addis Ababa
Creators: name: Abebe, Kassie
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: Mobile broadband services are undergoing a period of dramatic growth causing a tremendous increase in data tra c. One main reason for this rise of tra c is being driven by the growing number of mobile subscribers. This increment in data tra c is handled by new technologies. LTE-Advanced extends the capabilities originally de ned in LTE to increase data throughput by using a combination of new technologies, like Orthogonal Frequency Division Multiple Access (OFDMA), Carrier Aggregation (CA) and Multi Input Multi Output (MIMO) techniques. CA is one of the most signi cant LTE-Advanced features that combine multiple Component Carriers (CCs) across an available spectrum to create a wider bandwidth channel for increasing the network data throughput and overall capacity. This thesis analyzes throughput enhancement using CA technique, by conducting radio propagation using WinProp and system level simulation using Matlab, for di erent CA scenarios of a selected high tra c area in Addis Ababa city, Ethiopia. The addition of 10 MHz CC over 20 CC provides 49%, and 20 MHz provides 105% throughput gains at cell center for case of 1800 MHz (band 3). All the three frequency bands (1800 MHz, 2600 MHz (band 7) and 3700 MHz (band 43)) with two 20 MHz CC provide over 100% throughput gain at the cell center, compare to 1 CC at 1800 MHz. When using low frequency bands, such as the 1800 MHz band, the Signal to Interference and Noise Ratio (SINR) value is low thus providing a better throughput from the cell center to edge.