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Abstract

Nowadays heuristic methods are one of the most used tools for the optimization of problems. The proof of that is the fact that they are widely used in chemistry, economics and energy. Among the most popular of heuristic methods belongs differential evolution, belonging to the so-called ‘evolutionary algorithms’. They can handle difficult, large-scale problems with many parameters, like the optimization of the hydro-thermal coordination of hydro and thermal power plants. As with any other method, differential evolution also has certain parameters. These parameters, among others, are the size of the population, the maximum number of generations, crossover parameter and mutation factor. The effect of these parameters on the results of an optimization using differential evolution is the focus of this paper. The hydro-thermal coordination of one hydro and one thermal power plant was used as an example to explain this issue.

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Abstract

As streets cover almost twenty-five percentages of the urban open spaces, designing streets is a vital issue in creating thermal comfort for urban environmental design. The geometry of the street (height/width ratio) as well as orientation directly influences the airspeed, solar access in urban canyon and as a result thermal comfort at the pedestrian level. This study examined the street geometry case study's scenarios with different street geometries and investigates its effects on outdoor thermal comfort as well as the weather parameters. However, according to the matrix assessment conducted by the author, the vast street canyons (height/width=0.65 m/14.5 m with an orientation parallel to the prevailing wind direction achieved the best results. Nevertheless, the aim of this paper is to investigate the impact of street canyon geometry on outdoor thermal comfort and its parameters in the summertime using numerical modeling.

Open access

Abstract

This research aims to evaluate the effectiveness of implementing quantitative techniques to improve decision making in construction projects by using time- and cost-oriented failure mode and effect analysis and Monte Carlo simulation. This research is limited to the project schedule and risk management of one phase of a construction project to build a new automated warehouse in Hungary. The results show that there are 80% and 100% chances that the duration and cost of the construction project phase will increase due to the uncertainty and individual risks associated with the construction project activities respectively.

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Most of red wine's health benefits are attributed to polyphenols, which can express different biological effects. During ageing process, numerous chemical reactions occur, alternating phenolic composition of wine. Therefore, this paper focused on the influence of ageing on the evolution of wine phenolics (phenolic acids, flavonoids, stilbenes, and anthocyanins). Wines from 4 local grape varieties (Frankovka, Portugieser, Probus, and Rumenika) were analysed after 1 month and 4 years of ageing. Monomeric anthocyanin and total phenolic contents and antioxidative potential in aged wines were also determined. Among tested phenolics, main components in aged wines remained gallic acid (2.16–19.55 mg l−1) and catechin (8.39–37.21 mg l−1). The most prominent changes of analysed phenolic compounds during ageing were observed for p-coumaric acid (from +173.3% to +763.1%) and malvidin-3-glucoside (from +173.3% to +763.1%). Wine from Rumenika variety maintained the highest content of individual phenols after ageing. Additionally, aged wines had very low content of monomeric anthocyanins. Significant correlation (r= −0.93, P<0.05) between total phenolic content and IC50 values in aged wines was also noticed. Obtained results provide useful information about the quality preservation during aging and storage of these products.

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Abstract

In this paper a detailed description of a method is presented to estimate the minimum structural dimensions of the robot arms. A comparative study is conducted between the harmony search and artificial bee colony algorithms in this scientific application. The comparison process was done through the kinematic equations of the serial robot manipulator to find the optimum lengths of links of the robot. A novel design for a seven-degrees-of-freedom robot arm was presented to conduct the comparative study on the presented optimization algorithms. This novel robot mimics the functionality of the SANDVIK robot arm for tunnelling works, but the presented type synthesis was designed to overcome the restrictions on the original SANDVIK arm.

Open access

User experience is vital in usability evaluation to understand all aspects of user interactions with a product or system. The usability includes user satisfaction, efficiency, and effectiveness to achieve certain goals. On the other hand, to support the sustainability of the business, it is necessary to know the factors that significantly affect purchase intention through online travel booking application. The main aim of this paper is to investigate the usability of online travel booking system and consumer-level factors of purchase intention in online travel booking application. The research attempt to find whether product diagnosticity influences perceived quality and product trust and generally impacts purchase intention. In this study, we select an existing online travel booking application named Traveloka. The system usability scales (SUS) were used to evaluate the usability for web applications. A total of 1,225 respondents participate in online questionnaire using Google form. Most of the respondents recruited are based in Jakarta, Indonesia. The overall SUS score is only 56.13 from 100. The results show that intention for purchase is influenced by product trust and perceived quality. Moreover, the product diagnosticity (PD) supported perceived quality (PQ) and product trust (PT), and variable of product trust (PT) also supported perceived quality (PQ).

Open access

Abstract

This paper presents a proprietary open source code for analysis of granulometric properties of bed load material based on non-intrusive automated image analysis. Vertical bed-surface images are processed using the proposed tool and verified with results obtained by well tested optical granulometry tool Basegrain. The practical application of the proposed tool yields accuracy comparable that of the tested framework and traditional sampling methods. Additionally, results showed that the average D50 grain-size sampled from riverbed of studied river section of river Danube agrees up to 95% with the average D50 sampled from riverbanks.

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Fifteen strains of Bacillus spp. (three B. cereus strains, one B. subtilis, B. macerans, B. pumilus, and B. mycoides strains, and eight unknown isolates from the food-industry) were identified on species level with three designed pairs of primers for B. cereus, B. licheniformis, and B. subtilis. Primers designed for B. licheniformis (BlichF and BlichR) and B. subtilis (BsubF and BsubR) allowed specific species identification, whereas the designed pair of primers for B. cereus (BcerF2 and BcerR2) showed specificity for B. cereus sensu lato, because both B. cereus strains and B. mycoides gave positive reaction. Bacilli identification was also carried out with routine API method with unsatisfactory results. The (GTG)5-PCR method was used for strain characterization, enabling bacilli classification into separate clusters according to their taxonomic designations.

Open access
On the design of class-J microwave power amplifier

Due to the ISM band being unlicensed for communication applications, a lot of applications have been developed in this band and a good example is WiFi IEEE 802.11a, b, g, n of Bluetooth. This numeracy of applications motivated this paper. The paper is concerned with the design of a low distortion 20 dBm 2.4 GHz class-J power amplifier (PA) since PAs are indispensable in radio communications. The design is based on the AVAGO ATF-52189 transistor with a transition frequency of 6 GHz. The design is done as a hybrid circuit network realized using microstrip elements and surface mount device (SMD) capacitors. The schematic design and simulation are carried out using Keysight's Advanced Design System version 2016.01. The simulated PA exhibited a drain efficiency of 69% and a power output of 21 dBm.

Open access

Providing quality requirements in Software Engineering is vital to ensure the product developed is able to deploy and function to meet the operational objectives. Software Requirement Engineering is the most complex process because it involves the integration of human, logics and process. Extracting or capturing what customers need and want is called Requirement Elicitation (RE) and it is the most crucial process in requirement engineering. If handled poorly, the cost of the failures would be very expensive. Most of the software projects that failed were due to poor requirements which occurred at RE phase. Thus, enhancing and optimizing the RE methods have been subject to a long research debate to ensure quality requirements are captured. Recently, Lean Six Sigma (LSS) had emerged as part of a continuous improvement in Software Development Life Cycles (SDLC). LSS is known for a systematic and structure business improvement successfully deployed in many fields of industry that contributes a significant gain not only in quality of products and services but also in operational costs and delivery. The objective of the research is to develop an integrated conceptual framework of LSS principles with Software Requirement Engineering methodology to optimize RE process. The article will produce conceptual framework as the comprehensive guidelines to capture quality software requirements.

Open access