Periodicals of Engineering and Natural Sciences (PEN - International University of Sarajevo)
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An Integrated Optimization approach to locate the D-STATCOM in Power Distribution system to reduce the power loss and Total Cost
Get PDFThe optimization problem with a single objective can obtain a single solution, called an optimal solution. It maximizes or minimizes the performance of a particular objective function to a given constraint. But, in the case of the multi-objective optimization, different objectives can be simultaneously optimized. Thus, this paper recommends a multi-objective optimization methodology for simultaneously perform the two objective functions such as resizing and optimal placement of Distributed Static Compensator (DSTATCOM) for reducing the power loss, total cost and enhancing the voltage profile. For these purposes, an integrated approach of two optimization algorithm called Multi-objective Ant Colony Optimization (MACO) and Bacterial Foraging Optimization Algorithm (BFOA) are used. The prime intention of this work is to bring down the power loss, total cost and enhance the voltage profile by placing the DSTATCOM device in an optimal location. Here, IEEE-30 and IEEE-69 bus systems are considered to appraise the recital of the recommended approach. Moreover, the effectiveness of the MACO-BFOA approach is evaluated and compared with other multi-objective algorithms. From this analysis, it is observed that when compared to these techniques, the proposed system provides the minimized power loss and total cost
Optimization of Process Parameters of Cryogenic Treatment on AL/AL2O3 MMCs by Taguchi Method for Tensile Strength.
Get PDFEngineering materials are given different types of treatment to impart desired properties to the materials to make them suitable for the intended application. The conventional method is heat treatment. It is being followed by many centuries but the treatment of materials below the room temperature is altogether a new concept to enhance the material properties. When the materials are subjected to deep freezing up to -1960C the change in the morphology results in the stability of microstructure & dimensions. Many researchers have proved the usefulness of cryogenic treatment on ferrous materials. But a very little amount of work has been found in the area of nonferrous materials. Taguchi approach was applied to optimize the process parameters of cryogenic treatment on Al6061-Al2O3 MMCs. The results were experimentally validated. It is found that, the Taguchi approach can be used as an effective tool in optimizing the process variables to minimise the laborious effort in conduction of experiments. 
Single solar cell ideality factor determination using a fixed point method
Get PDFThe modeling and extraction of solar cell parameters are the crucial steps for simulating and optimizing the photovoltaic systems to meet specific properties. These parameters are directly related to the current-voltage characteristic of the solar cell under illumination, the latter is generally represented, by an equivalent electrical circuit whose parameters (the shunt resistance , the saturation current, the series resistance and the ideality factor of the diode) have been the subject of several researches. This paper describes an iterative algorithm based on fixed point method to calculate the ideality factor of a photovoltaic cell. The procedure uses the electrical and mathematical equations governing the solar cell behavior. The obtained results were compared to the previous works to show its effeteness
Determination of Pozzolanic Activity for Using Natural Zeolite Analcime in Sustainability Additive Cement Products
Get PDFIt is known that the cement industry is responsible for 5-8% of world CO2 emissions and also for intensive energy consumption. For this reason, cement productions need to sustainability studies. Mineral admixtures added to cement as partial replacement material enable to sustainable blended cement productions due to used less amount of cement. Mineral admixtures with pozzolanic property are also preferred in terms of increasing cement performances. This situation corresponds to improved performance of cement and concrete products as well as saving energy, reducing world CO2 emissions. In recent years, the cement industry has been using natural zeolites extensively as pozzolanic materials. Analcime is known as second valuable zeolite mineral after from clinoptilolite in natural zeolite groups The aim of this study is to determinate the pozzolanic properties of analcime and to investigate whether it has potential availability in sustainable blended cement production. The clinoptilolite was used with comparison purpose in this study. Blaine values, densities, chemical composions, pozzolanic activities, mineralogical structures of analcime and clinoptilolite which are subject of study were determined. Accordance with TS 25, which contains pozzolan conformity criterias, 7-days average compressive strength values of lime-pozzolan mixture samples were determined. The datas obtained shown that, the 7-days average compressive strengths of lime-zeolite (pozzolan) blended samples are 9.02 MPa for clinoptilolite and 6.3 MPa for analcime. The total content of Si02 + Al2O3 + Fe2O3 was 77.3% for clinoptilolite and 73.16% for analcime. Accordingly, analcime which is a natural zeolite satisfies to puzolan conformity criterias in TS 25 has the potential to be an alternative to clinoptilolite which is more widely used in cement productions
Iterative multipacket detection with FDE based MAC protocol in vehicular ad hoc networks
Get PDFWireless access in vehicular environments (WAVE), is especially designed to support vehicular ad hoc networks (VANETs) requirements, where rapidly changing channel conditions introduces unsynchronized transmissions. In such networks, instead of dealing with interferences in medium access control (MAC) layer or physical layer alone, both layers should be considered to cooperate and complement each other. In this paper, multipacket detection (MPD) technique with frequency domain equalization (FDE) is proposed for VANETs, with cyclically shifted different interleavers for different nodes, to remove interference and reducing the information exchange between nodes. These promising multi-hop wireless networks are used in situations, where temporary network connectivity is needed. Therefore, to improve the communication between vehicles (V2V) and from vehicles to roadside infrastructure (V2I), MPD-FDE with interference cancellation (IC) schemes can be used iteratively to successfully decode and receive even colliding packets. For designing such a protocol, different key aspects are discussed with an emphasis on iterative MPD-FDE. Numerical results with different network nodes, show the MPD-FDE performances for coded and uncoded transmissions with different IC schemes, where successive IC (SIC) is much better than parallel IC (PIC) schemes. It is also shown that the proposed protocol provide reliable detection and excellent throughput improvements, with much less resource consumption compared to multiple random interleavers
An analytic study for the effect of antenna height on line-of-sight VHF/UHF communications coverage distance applied to Baghdad city
Get PDFA radio system conveys information from transmitter to the receiver. The information can be sent by any antenna that transforms the RF signal electromagnetically through free space medium for electromagnetic wave propagation. Long-distance data communication has been higher in effect through wireless networks. Generally, VHF and UHF radio frequencies are termed as line-of-sight (LOS). In point of fact, the considered horizon for visual LOS is not identical as the horizon for radio wave propagation because of geographic obstacles and the earth curvature limits LOS transmission. This research provides an overview, study, analysis, and implementing simulations with single-antenna and two-antenna systems using MATLAB programming language based on antenna height effect on determining the distance range that can be expected in a radio link. Also, the effects of weather and earth terrain changes effects on coverage distance are also taken in consideration. Baghdad city is considered as the place where the research ideas are applied
From AI‑personalized learning to green purchasing: A TPB-S‑D logic pathway via self-regulated learning, perceived knowledge gain, and attitudes in Jordan and Palestine
Get PDFThis study examines the possibilities of AI-enabled learning to be prolonged from the classroom to enable greener lifestyle decisions on an everyday basis, and conceptualizes that process as a platform governance and telecommunications policy problem. AI-powered personalization is thought of here as a data-hungry platform in markets for connectivity and in data, privacy, and algorithmic accountability regimes. Based on the theory of planned behavior and the service-dominant logic of value co-creation, we propose that personalization increases perceived knowledge and self-directed learning, which yield favorable attitudes toward sustainable consumption and thus green purchasing. Based on empirical data from Palestine and Jordan, we illustrate how infrastructure, affordability, and trust act as mediators of using, crediting, and converting personalization to social value. The contribution is twofold: it links learning gains to market-relevant dispositions in the platform governance setting, and it presents a design blueprint for regulators, ministries, and providers that pairs greater access with open data practices and incentives tied to authenticated learning outcomes. In general, the study positions AI-personalized learning as an editable digital platform whose social dividend is enhanced when telecommunications policy and data regulation are aligned with education and sustainability goals
Efficient read monotonic data aggregation across shards on the cloud
Get PDFClient-centric consistency models define the view of the data storage expected by a client in relation to the operations done by a client within a session. Monotonic reads is a client-centric consistency model which ensures that if a process has seen a particular value for the object, any subsequent accesses will never return any previous values. Monotonic reads are used in several applications like news feeds and social networks to ensure that the user always has a forward moving view of the data.
The idea of Monotonic reads over multiple copies of the data and for lightly loaded systems is intuitive and easy to implement. For example, ensuring that a client session always fetches data from the same server automatically ensures that the user will never view old data.
However, such a simplistic setup will not work for large deployments on the cloud, where the data is sharded across multiple high availability setups and there are several million clients accessing data at the same time. In such a setup it becomes necessary to ensure that the data fetched from multiple shards are logically consistent with each other. The use of trivial implementations, like sticky sessions, causes severe performance degradation during peak loads.
This paper explores the challenges surrounding consistent monotonic reads over a sharded setup on the cloud and proposes an efficient architecture for the same. Performance of the proposed architecture is measured by implementing it on a cloud setup and measuring the response times for different shard counts. We show that the proposed solution scales with almost no change in performance as the number of shards increases
Color codes: compаrаtive conclusions
Get PDFThis pаper presents new reseаrch results on the Color code method for а reаl time leаrning process аssessment. The method uses three color codes: red for "problem", yellow for "work in progress" аnd green for "job done". The buttons of colors аre incorporаted in the EdX LMS аnd аre аlwаys shown on the screen. The experiment took pаrt in the Аutumn of 2018 with 1st yeаr Rigа Technicаl University mаster stu-dents. Results show thаt 75% of the students used the color buttons. This is а big difference compаred to the 2017 bаchelor students from which only 34% of the students hаd used the color buttons. Differences in pushed button colors: 44% of green or “Done” pushes from the 2018 mаster students, but 67% from the 2017 Bаchelors, аnd 49% yellow or “Process” pushes from the 2018 mаsters versus only 25% from 2017 bаchelors; Red button “Problem” in 2018 wаs used 7%, which is the sаme аs from the 2017. It could point to а trend thаt 7% of аny course mаteriаl is either poorly executed (technicаlly or content-wise) or а minor pаrt of the students hаve difficulties in understаnding the mаteriаl, most believаbly it is а cаse of the mix of them both. А tendency thаt bаchelor students hаd more concentrаted on finishing the leаrning mаteriаls, but the mаster students – more on the leаrning process itself cаn be observed
Eye-tracking introduction considerations in vestibular telerehabilitation in Latvia
Get PDFThe terms of telemedicine, telerehabilitation, and e-care have come into our everyday lives as the necessity to make medical assistance and care more effective. These terms are not buzzwords. Indeed, new technology, innovative solutions, offered by programming tools, modern sensor equipment, wearable devices and bio-signal data sets, provide an ability to ensure necessary remote support to a person with special needs anytime and anywhere. This assistance may include person’s online health monitoring, telerehabilitation and health improvement measures, mobile training, rapid alert button initiation, advisory support, and a set of many other measures supporting patient’s care.
This paper displays achievements in creation of vestibular telerehabilitation tools and systems, particularly in Latvia, and discuss further necessary developments, including eye-tracking instruments, which would improve existing telerehabilitation systems