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Patrice Umenne

Bio: Patrice Umenne is an academic researcher from University of South Africa. The author has contributed to research in topics: Femtosecond & Josephson effect. The author has an hindex of 3, co-authored 23 publications receiving 44 citations. Previous affiliations of Patrice Umenne include Sewanee: The University of the South.

Papers
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Proceedings ArticleDOI
22 Aug 2018
TL;DR: The significance of these results is that it presents Mininet-WiFi as an emulator, which can be integrated into a real programmable networking environment offering a portable, cost effective and easily deployable testing network, which could be run on a single computer.
Abstract: In this paper, Mininet-WiFi was used to simulate a Software Defined Network to demonstrate Mininet-WiFi's ability to be used as the Software Defined Network emulator which can also be integrated to the existing network using a Network Virtualized Function A typical organization's computer network was simulated which consisted of a website hosted on the LAMP (Linux, Apache, MySQL, PHP) virtual machine, and an F5 application delivery controller (ADC) which provided load balancing of requests sent to the web applications A website page request was sent from the virtual stations inside Mininet-WiFi The request was received by the application delivery controller, which then used round robin to send the request to one of the web servers on the LAMP virtual machine The web server then returned the requested website to the requesting virtual stations using the simulated virtual network The significance of these results is that it presents Mininet-WiFi as an emulator, which can be integrated into a real programmable networking environment offering a portable, cost effective and easily deployable testing network, which can be run on a single computer These results are also beneficial to modern network deployments as the live network devices can also communicate with the testing environment for the data center, cloud and mobile provides

12 citations

Proceedings ArticleDOI
07 Dec 2018
TL;DR: In this paper, a Software Defined Network was created in Mininet using python script and an external interface was added in the form of an OpenDaylight controller to enable communication with the network outside of Mininet.
Abstract: In this paper, a Software Defined Network was created in Mininet using python script. An external interface was added in the form of an OpenDaylight controller to enable communication with the network outside of Mininet. The OpenDaylight controller was hosted on the Amazon Web Services elastic computing node. This controller is used as a control plane device for the switch within Mininet. The OpenDaylight controller was able to create the flows to facilitate communication between the hosts in Mininet and the webserver in the real-life network. In order to test the network, a real life network in the form of a webserver hosted on the Emulated Virtual Environment – Next Generation (EVE-NG) software was connected to Mininet.

12 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate the fabrication of micron and sub-micron sized constrictions on high YBa2Cu3O7−x (YBCO) thin films using the femtosecond laser.
Abstract: We demonstrate the fabrication of micron and sub-micron sized constrictions on high $${T}_{c}$$ superconducting YBa2Cu3O7−x (YBCO) thin films using the femtosecond laser. The lithography process was optimized by programming the movement of the translation stage during etching with G-code (a control systems programming language), controlling the power incident on the sample to a certain degree and by bringing the laser ablation spots close to one another without clipping the constriction. S-shaped constrictions of micron and sub-micron size (smallest being ~858 nm) have been fabricated to be used as the constriction type Josephson junctions. The constrictions made have a variable width, with the width measured at the narrowest point.

11 citations

Proceedings ArticleDOI
09 Sep 2020
TL;DR: Intelligent Electronic Devices (IED) that use ethernet for communicating with substation devices on the grid where modelled in OPNET and showed that with an increase in number of nodes there was a increase in packet delay as well as the network load.
Abstract: In this paper Intelligent Electronic Devices (IED) that use ethernet for communicating with substation devices on the grid where modelled in OPNET. There is a need to test the communication protocol performance over the network. A model for the substation communication network was implemented in OPNET. This was done for ESKOM, which is the electrical power generation and distribution authority in South Africa. The substation communication model consists of 10 ethernet nodes which simulate protection Intelligent Electronic Devices (IEDs), 13 ethernet switches, a server which simulates the substation Remote Terminal Unit (RTU) and the DNP3 Protocol over TCP/IP simulated on the model. DNP3 is a protocol that can be used in a power utility computer network to provide communication service for the grid components. It was selected as the communication protocol because it is widely used in the energy sector in South Africa. The network load and packet delay parameters were sampled when 10%, 50%, 90% and 100% of devices are online. Analysis of the results showed that with an increase in number of nodes there was an increase in packet delay as well as the network load. The load on the network should be taken into consideration when designing a substation communication network that requires a quick response such as a smart gird.

5 citations

Proceedings ArticleDOI
09 Dec 2019
TL;DR: This paper presents the design of a photovoltaic based power supply using a non-inverting buck-boost converter to charge batteries to present a constant output of 48 V charging voltage for the batteries even though the input voltage may vary depending on the amount of solar irradiation falling on the solar panel.
Abstract: This paper presents the design of a photovoltaic based power supply using a non-inverting buck-boost converter to charge batteries. The batteries can be used to power a load as back-up power when there is no sunlight. This approach presents a constant output of 48 V charging voltage for the batteries even though the input voltage may vary depending on the amount of solar irradiation falling on the solar panel. Solar charge controllers are important components in such an off-grid system because they can be used to protect the battery bank from overcharging and regulate the charging current. The buck-boost converter is used as a solar charge controller to maximize the charging voltage when the solar irradiation provides less than the required output voltage. The DC-DC converter (buck-boost converter) was modelled using the SIMetrix software to demonstrate the expected output waveforms before building the complete PV power supply.

4 citations


Cited by
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DOI
01 Dec 2021
TL;DR: The femtosecond laser precision engineering is a significant advanced processing way for high-quality micro-/nanostructure fabrication, especially to achieve novel functional photoelectric structures and devices as discussed by the authors.
Abstract: As a noncontact strategy with flexible tools and high efficiency, laser precision engineering is a significant advanced processing way for high-quality micro-/nanostructure fabrication, especially to achieve novel functional photoelectric structures and devices. For the microscale creation, several femtosecond laser fabrication methods, including multiphoton absorption, laser-induced plasma-assisted ablation, and incubation effect have been developed. Meanwhile, the femtosecond laser can be combined with microlens arrays and interference lithography techniques to achieve the structures in submicron scales. Down to nanoscale feature sizes, advanced processing strategies, such as near-field scanning optical microscope, atomic force microscope, and microsphere, are applied in femtosecond laser processing and the minimum nanostructure creation has been pushed down to ~25 nm due to near-field effect. The most fascinating femtosecond laser precision engineering is the possibility of large-area, high-throughput, and far-field nanofabrication. In combination with special strategies, including dual femtosecond laser beam irradiation, ~15 nm nanostructuring can be achieved directly on silicon surfaces in far field and in ambient air. The challenges and perspectives in the femtosecond laser precision engineering are also discussed.

69 citations

Journal ArticleDOI
05 May 2021
TL;DR: A Home Security Alarm was made using WEMOS D1 and HC-SR501 Sensor with Telegram Notification to help the community in dealing with the theft that enters the house.
Abstract: —Home Security Alarms in today's modern society only use CCTV that can only see the person without any notification that goes into the cellphone in dealing with the theft that occurred. To help the community in dealing with the theft that enters the house, a Home Security Alarm was made using WEMOS D1 and HC-SR501 Sensor with Telegram Notification. The whole tool is divided into several parts which consist of HC-SR501 Sensor, WEMOS D1 and Buzzer. This tool works when the WEMOS D1 microcontroller processes the pear sensor as a motion detector and buzzer as a sound alarm if motion is detected, then the notification automatically enters into the Telegram Application, With this tool can monitor directly if anyone enters the house while being left .

21 citations

Journal ArticleDOI
TL;DR: The future implications of Blockchain are considered, as the concept of disintermediated trustless ledgers stimulates the imagination of computer scientists and innovators, and how Blockchain may be integrated into the university level computer science and information technology curriculum is discussed.
Abstract: Blockchain ledgers and the Cloud are a perfect match. On the one hand, there is an inherent requirement for multiple separate authentication nodes to validate every Blockchain transaction with each node requiring substantial encryption calculation capability. On the other hand, massive economies of scale can bring down the cost per transaction, and provide service continuity. Additionally, the Cloud provides a perfect incubator for proof-of-concept projects. This paper considers the future implications of Blockchain, as the concept of disintermediated trustless ledgers stimulates the imagination of computer scientists and innovators. The Cloud’s role in implementing this new paradigm is also highlighted, as a new decentralized P2P-Cloud model. Finally, this paper discusses how Blockchain may be integrated into the university level computer science and information technology curriculum.

20 citations

01 Jan 2003
TL;DR: In this article, two-photon polymerization of inorganic-organic hybrid materials initiated by femtosecond Ti:sapphire laser pulses is performed. And first applications of this technique for the fabrication of three-dimensional microstructures and photonic crystals in inorganicorganic hybrid polymers with a structure size down to 200 nm and a periodicity of 450 nm are discussed.
Abstract: Investigations of two-photon polymerization of inorganic-organic hybrid materials initiated by femtosecond Ti:sapphire laser pulses are performed. First applications of this technique for the fabrication of three-dimensional microstructures and photonic crystals in inorganic-organic hybrid polymers with a structure size down to 200 nm and a periodicity of 450 nm are discussed.

17 citations