Search results for: hit-or-miss operator transform

Authors: M. Moyzykh, I. Klichuk, L. Sabirov, D. Kolomentseva, E. Magommedov

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Modern city electrical grids are forced to increase their density due to the increasing number of customers and requirements for reliability and resiliency. However, progress in this direction is often limited by the capabilities of existing network equipment. New energy sources or grid connections increase the level of short-circuit currents in the adjacent network, which can exceed the maximum rating of equipment–breaking capacity of circuit breakers, thermal and dynamic current withstand qualities of disconnectors, cables, and transformers. Superconducting fault current limiter (SFCL) is a modern solution designed to deal with the increasing fault current levels in power grids. The key feature of this device is its instant (less than 2 ms) limitation of the current level due to the nature of the superconductor. In 2019 Moscow utilities installed SuperOx SFCL in the city power grid to test the capabilities of this novel technology. The SFCL became the first SFCL in the Russian energy system and is currently the most powerful SFCL in the world. Modern SFCL uses second-generation high-temperature superconductor (2G HTS). Despite its name, HTS still requires low temperatures of liquid nitrogen for operation. As a result, Moscow SFCL is built with a cryogenic system to provide cooling to the superconductor. The cryogenic system consists of three cryostats that contain a superconductor part and are filled with liquid nitrogen (three phases), three cryocoolers, one water chiller, three cryopumps, and pressure builders. All these components are controlled by an automatic control system. SFCL has been continuously operating on the city grid for over three years. During that period of operation, numerous faults occurred, including cryocooler failure, chiller failure, pump failure, and others (like a cryogenic system power outage). All these faults were eliminated without an SFCL shut down due to the specially designed cryogenic system backups and quick responses of grid operator utilities and the SuperOx crew. The paper will describe in detail the results of SFCL operation and cryogenic system maintenance and what measures were taken to solve and prevent similar faults in the future.

Keywords: superconductivity, current limiter, SFCL, HTS, utilities, cryogenics

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Authors: Zhangquan Zhou, Guilin Qi

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Materialization is an important reasoning service for applications built on the Web Ontology Language (OWL). To make materialization efficient in practice, current research focuses on deciding tractability of an ontology language and designing parallel reasoning algorithms. However, some well-known large-scale ontologies, such as YAGO, have been shown to have good performance for parallel reasoning, but they are expressed in ontology languages that are not parallelly tractable, i.e., the reasoning is inherently sequential in the worst case. This motivates us to study the problem of parallel tractability of ontology materialization from a theoretical perspective. That is we aim to identify the ontologies for which materialization is parallelly tractable, i.e., in the NC complexity. Since the NC complexity is defined based on Boolean circuit that is widely used to investigate parallel computing problems, we first transform the problem of materialization to evaluation of Boolean circuits, and then study the problem of parallel tractability based on circuits. In this work, we focus on datalog rewritable ontology languages. We use Boolean circuits to identify two classes of datalog rewritable ontologies (called parallelly tractable classes) such that materialization over them is parallelly tractable. We further investigate the parallel tractability of materialization of a datalog rewritable OWL fragment DHL (Description Horn Logic). Based on the above results, we analyze real-world datasets and show that many ontologies expressed in DHL belong to the parallelly tractable classes.

Keywords: ontology materialization, parallel reasoning, datalog, Boolean circuit

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Authors: Abdul Ghafar, Malini Nair

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Non-governmental organizations have been seemed to struggle the battle of balancing many concerns with corporates which may impact on their financial solvency. Some of these concerns relates to uphold the relationship where weighing up the impacts of their involvement with corporates takes priority over the main purpose of creating valuable impacts for communities. To some extent, it can be argued that NGOs are influenced by corporates’ power to tackle contemporary issues rather than eradicating the root causes of such issues and transform the results into more sustainable manner. NGOs spend massive amount of energy, time and resources in order to move some corporates to embrace their social responsibilities. It has become a norm, where an active NGO that is becoming more successful on building partnerships with corporates is perceived to be more socially responsible. In contrast to this, as some researchers argue that the social responsibility for NGOs is not a voluntary act; they must exhibit the core values in all their practices require much attention to address. This article stresses the need of understanding ‘Social Responsibility’ of NGOs that stem from an argument that NGOs tend to act on narrow mandate rather than considering broader outcomes of their CSR initiatives. This paper argues that NGOs must focus on building capabilities of the recipients from CSR initiatives which should serve as a core value of partnerships mandate between NGOs, Corporates and Governments. We argue that SEN’s Capabilities Approach can further enhance the mainstream CSR agenda of NGOs which seems to incline more towards providing palliative solutions to social issues.

Keywords: non-profit organization, corporate social responsibility, partnerships, capabilities approach

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Authors: R. S. Yadav, J. Havlica, I. Kuřitka, Z. Kozakova, J. Masilko, L. Kalina, M. Hajdúchová, V. Enev, J. Wasserbauer

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Nickel spinel ferrite NiFe2O4 nanoparticles with different particle size at different annealing temperature were synthesized using the starch-assisted sol-gel auto-combustion method. The synthesized nanoparticles were characterized by conventional powder X-ray diffraction (XRD) spectroscopy, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, Field-Emission Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Vibrating Sample Magnetometer. The XRD patterns confirmed the formation of NiFe2O4 spinel ferrite nanoparticles. Field-Emission Scanning Electron Microscopy revealed that particles are of spherical morphology with particle size 5-20 nm at lower annealing temperature. An infrared spectroscopy study showed the presence of two principal absorption bands in the frequency range around 525 cm-1 (ν1) and around 340 cm-1 (ν2); which indicate the presence of tetrahedral and octahedral group complexes, respectively, within the spinel ferrite nanoparticles. Raman spectroscopy study also indicated the change in octahedral and tetrahedral site related Raman modes in nickel ferrite nanoparticles with change of particle size. This change in magnetic behavior with change of particle size of NiFe2O4 nanoparticles was observed.

Keywords: nickel ferrite, nanoparticles, magnetic property, NiFe2O4

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Authors: Ljerka Kratofil Krehula, Martina Perlog, Jasmina Stjepanović, Vanja Gilja, Marijana Kraljić Roković, Zlata Hrnjak-Murgić

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The composite preparation of titanium dioxide and zinc oxide photocatalysts with the conductive polymers gives the opportunity to carry out the catalysis reactions not only under UV light but also under visible light. Such processes may efficiently use sunlight in degradation of different organic pollutants and present new design for wastewater treatment. The paper presents the preparation procedure, material characteristics and photocatalytic efficiency of polypyrrole/titanium dioxide and polypyrrole/zinc oxide composites (PPy/TiO2 and PPy/ZnO). The obtained composite samples were characterized by Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and thermogravimetric analysis (TGA). The photocatalytic efficiency of the samples was determined following the decomposition of Acid Blue 25 dye (AB 25) under UV and visible light by UV/Vis spectroscopy. The efficiency of degradation is determined by total organic carbon content (TOC) after photocatalysis processes. The results show enhanced photocatalytic efficiency of the samples under visible light, so the prepared composite samples are recognized as efficient catalysts in degradation process of AB 25 dye. It can be concluded that the preparation of TiO2 or ZnO composites with PPy can serve as a very efficient method for the improvement of TiO2 and ZnO photocatalytic performance under visible light.

Keywords: composite, photocatalysis, polypyrrole, titanium dioxide, zinc oxide

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Authors: Danar Agus Susanto, Hermawan Febriansyah, Meilinda Ayundyahrini

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The availability of spring water to meet people demand is often a problem, especially in tropical areas with very limited surface water sources, or very deep underground water. Although the technology and equipment of pumping system are available and easy to obtain, but in remote areas, the availability of pumping system is difficult, due to the unavailability of fuel or the lack of electricity. Solar Water Pumping System (SWPS) became one of the alternatives that can overcome these obstacles. In the tropical country, sunlight can be obtained throughout the year, even in remote areas. SWPS were already widely built in Indonesia, but many encounter problems during operations, such as decreased of efficiency; pump damaged, damaged of controllers or inverters, and inappropriate photovoltaic performance. In 2011, International Electrotechnical Commission (IEC) issued the IEC standard 62253:2011 titled Photovoltaic pumping systems - Design qualification and performance measurements. This standard establishes design qualifications and performance measurements related to the product of a solar water pumping system. National Standardization Agency of Indonesia (BSN) as the national standardization body in Indonesia, has not set the standard related to solar water pumping system. This research to study operational procedures of SWPS by adopting of IEC Standard 62253:2011 to be Indonesia Standard (SNI). This research used literature study and field observation for installed SWPS in Indonesia. Based on the results of research on SWPS already installed in Indonesia, IEC 62253: 2011 standard can improve efficiency and reduce operational failure of SWPS. SWPS installed in Indonesia still has GAP of 51% against parameters in IEC standard 62253: 2011. The biggest factor not being met is related to operating and maintenance handbooks for personnel that included operation and repair procedures. This may result in operator ignorance in installing, operating and maintaining the system. The Photovoltaic (PV) was also the most non-compliance factor of 71%, although there are 22 Indonesia Standard (SNI) for PV (modules, installation, testing, and construction). These research samples (installers, manufacturers/distributors, and experts) agreed on the parameter in the IEC standard 62253: 2011 able to improve the quality of SWPS in Indonesia. Recommendations of this study, that is required the adoption of IEC standard 62253:2011 into SNI to support the development of SWPS for remote areas in Indonesia.

Keywords: efficiency, inappropriate installation, remote areas, solar water pumping system, standard

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Authors: Aya Al Masri, Stefaan Carpentier, Fabrice Leroy, Thibault Julien, Safoin Aktaou, Malorie Martin, Fouad Maaloul

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Introduction: During an 'Interventional Radiology (IR)' procedure, the patient's skin-dose may become very high for a burn, necrosis and ulceration to appear. In order to prevent these deterministic effects, an accurate calculation of the patient skin-dose mapping is essential. For most machines, the 'Dose Area Product (DAP)' and fluoroscopy time are the only information available for the operator. These two parameters are a very poor indicator of the peak skin dose. We developed a mathematical model that reconstructs the magnitude (delivered dose), shape, and localization of each irradiation field on the patient skin. In case of critical dose exceeding, the system generates warning alerts. We present the results of its comparison with clinical studies. Materials and methods: Two series of comparison of the skin-dose mapping of our mathematical model with clinical studies were performed: 1. At a first time, clinical tests were performed on patient phantoms. Gafchromic films were placed on the table of the IR machine under of PMMA plates (thickness = 20 cm) that simulate the patient. After irradiation, the film darkening is proportional to the radiation dose received by the patient's back and reflects the shape of the X-ray field. After film scanning and analysis, the exact dose value can be obtained at each point of the mapping. Four experimentation were performed, constituting a total of 34 acquisition incidences including all possible exposure configurations. 2. At a second time, clinical trials were launched on real patients during real 'Chronic Total Occlusion (CTO)' procedures for a total of 80 cases. Gafchromic films were placed at the back of patients. We performed comparisons on the dose values, as well as the distribution, and the shape of irradiation fields between the skin dose mapping of our mathematical model and Gafchromic films. Results: The comparison between the dose values shows a difference less than 15%. Moreover, our model shows a very good geometric accuracy: all fields have the same shape, size and location (uncertainty < 5%). Conclusion: This study shows that our model is a reliable tool to warn physicians when a high radiation dose is reached. Thus, deterministic effects can be avoided.

Keywords: clinical experimentation, interventional radiology, mathematical model, patient's skin-dose mapping.

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Authors: Ingrid Argote, John Archila, Marcelo Becker

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In agriculture, intelligent systems applications have generated great advances in automating some of the processes in the production chain. In order to improve the efficiency of those systems is proposed a vision system to estimate the amount of fruits in sweet orange trees. This work presents a system proposal using capture of thermal images and fuzzy logic. A bibliographical review has been done to analyze the state-of-the-art of the different systems used in fruit recognition, and also the different applications of thermography in agricultural systems. The algorithm developed for this project uses the metrics of the fuzzines parameter to the contrast improvement and segmentation of the image, for the counting algorith m was used the Hough transform. In order to validate the proposed algorithm was created a bank of images of sweet orange Citrus (L.) Osbeck acquired in the Maringá Farm. The tests with the algorithm Indicated that the variation of the tree branch temperature and the fruit is not very high, Which makes the process of image segmentation using this differentiates, This Increases the amount of false positives in the fruit counting algorithm. Recognition of fruits isolated with the proposed algorithm present an overall accuracy of 90.5 % and grouped fruits. The accuracy was 81.3 %. The experiments show the need for a more suitable hardware to have a better recognition of small temperature changes in the image.

Keywords: Agricultural systems, Citrus, Fuzzy logic, Thermal images.

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Authors: Martial Pouzet, Marc Dubois, Karine Charlet, Alexis Béakou

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The availability, the ecologic and economic characteristics of wood are advantages which explain the very wide scope of applications of this material, in several domains such as paper industry, furniture, carpentry and building. However, wood is a hygroscopic material highly sensitive to ambient humidity and temperature. The swelling and the shrinking caused by water absorption and desorption cycles lead to crack and deformation in the wood volume, making it incompatible for such applications. In this study, dynamic fluorination using F2 gas was applied to wood samples (douglas and silver fir species) to decrease their hydrophilic character. The covalent grafting of fluorine atoms onto wood surface through a conversion of C-OH group into C-F was validated by Fourier-Transform infrared spectroscopy and 19F solid state Nuclear Magnetic Resonance. It revealed that the wood, which is initially hydrophilic, acquired a hydrophobic character comparable to that of the Teflon, thanks to fluorination. A good durability of this treatment was also determined by aging tests under ambient atmosphere and under UV irradiation. Moreover, this treatment allowed obtaining hydrophobic character without major structural (morphology, density and colour) or mechanical changes. The maintaining of these properties after fluorination, which requires neither toxic solvent nor heating, appears as a remarkable advantage over other more traditional physical and chemical wood treatments.

Keywords: cellulose, spectroscopy, surface treatment, water absorption

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Authors: Patricia Jiménez, Rafael Corchuelo

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Nowadays the World Wide Web is the most popular source of information that relies on billions of on-line documents. Web mining is used to crawl through these documents, collect the information of interest and process it by applying data mining tools in order to use the gathered information in the best interest of a business, what enables companies to promote theirs. Unfortunately, it is not easy to extract the information a web site provides automatically when it lacks an API that allows to transform the user-friendly data provided in web documents into a structured format that is machine-readable. Rule-based information extractors are the tools intended to extract the information of interest automatically and offer it in a structured format that allow mining tools to process it. However, the performance of an information extractor strongly depends on the search heuristic employed since bad choices regarding how to learn a rule may easily result in loss of effectiveness and/or efficiency. Improving search heuristics regarding efficiency is of uttermost importance in the field of Web Information Extraction since typical datasets are very large. In this paper, we employ an information extractor based on a classical top-down algorithm that uses the so-called Information Gain heuristic introduced by Quinlan and Cameron-Jones. Unfortunately, the Information Gain relies on some well-known problems so we analyse an intuitive alternative, Termini, that is clearly more efficient; we also analyse other proposals in the literature and conclude that none of them outperforms the previous alternative.

Keywords: information extraction, search heuristics, semi-structured documents, web mining.

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Authors: Marcia Silva, Jayme Kolarik, Brennon Garthwait, William Lee, Hai-Feng Zhang

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Adsorption of lead by a natural porous material was studied to establish a baseline for the removal of heavy metals from drinking and waste water. Samples were examined under different conditions such as solution pH, solution concentration, solution temperature, and exposure time. New materials with potentially enhanced adsorption properties were developed by functionalizing the surface of the natural porous material to fabricate graphene based coated and sulfide based treated porous material. The functionalized materials were characterized with Fourier Transform Infrared Spectroscopy (FTIR), Raman, Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. Solution pH effect on removal efficiency has been investigated in acidic (pH = 4), neutral (pH = 6) and basic (pH = 10) pH levels. All adsorbent materials showed highest adsorption capacities at neutral pH levels. Batch experiment was employed to assess the efficacy for the removal of lead with the sorption kinetics and the adsorption isotherms being determined for the natural and treated porous materials. The addition of graphene-based and sulfide-based materials increased the lead removal capacity of the natural clean porous material. Theoretical calculations confirmed pseudo-second order model as kinetic mechanism for lead adsorption for all adsorbents.

Keywords: heavy metals, ion exchange, adsorption, water remediation

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Authors: Titus Amodu Umoru

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The global economy today is full of sophistication. All over the world, business and marketing practices are undergoing an unprecedented transformation. In realization of this fact, the federal government of Nigeria has put in place a robust transformation agenda in order to put Nigeria in a better position to be a competitive player and in the process transform all sectors of its economy. New technologies, especially the internet, are the driving force behind this transformation. However, technology has inadvertently affected the way businesses are done thus necessitating the acquisition of new skills. In developing countries like Nigeria, citizens are still battling with effective application of those technologies. Obviously, students of business education need to acquire relevant business knowledge to be able to transit into the world of work on graduation from school and compete favourably in the labour market. Therefore, effective utilization of social media by both teachers and students can help extensively in empowering students with the needed skills. Social media which is described as a group of internet-based applications that build on the ideological foundations of Web 2.0, and which allow the creation and exchange of user-generated content, if incorporated into the classroom experience may be the needed answer to unemployment and poverty in Nigeria as beneficiaries can easily connect with existing and potential enterprises and customers, engage with them and reinforce mutual business benefits. Challenges and benefits of social media use in education in Nigeria universities were revealed in this study.

Keywords: business education, challenges, opportunities, utilization, social media

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Authors: Sandesh Achar

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Personalized advertising holds greater potential for higher conversion rates compared to generic advertisements. However, its widespread application in the retail industry faces challenges due to complex implementation processes. These complexities impede the swift adoption of personalized advertisement on a large scale. Personalized advertisement, being a data-driven approach, necessitates consumer-related data, adding to its complexity. This paper introduces an innovative data-driven decision-making framework, D3Advert, which personalizes advertisements by analyzing personalities using a BiLSTM network. The framework utilizes the Myers–Briggs Type Indicator (MBTI) dataset for development. The employed BiLSTM network, specifically designed and optimized for D3Advert, classifies user personalities into one of the sixteen MBTI categories based on their social media posts. The classification accuracy is 86.42%, with precision, recall, and F1-Score values of 85.11%, 84.14%, and 83.89%, respectively. The D3Advert framework personalizes advertisements based on these personality classifications. Experimental implementation and performance analysis of D3Advert demonstrate a 40% improvement in impressions. D3Advert’s innovative and straightforward approach has the potential to transform personalized advertising and foster widespread personalized advertisement adoption in marketing.

Keywords: personalized advertisement, deep Learning, MBTI dataset, BiLSTM network, NLP.

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Authors: David Krejci, Tony Schönherr, Quirin Koch, Valentin Hugonnaud, Lou Grimaud, Alexander Reissner, Bernhard Seifert

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In 2018 the NANO thruster became the first Field Emission Electric Propulsion (FEEP) system ever to be verified in space in an In-Orbit Demonstration mission conducted together with Fotec. Since then, 160 additional ENPULSION NANO propulsion systems have been deployed in orbit on 73 different spacecraft across multiple customers and missions. These missions included a variety of different satellite bus sizes ranging from 3U Cubesats to >100kg buses, and different orbits in Low Earth Orbit and Geostationary Earth orbit, providing an abundance of on orbit data for statistical analysis. This large-scale industrialization and flight heritage allows for a holistic way of gathering data from testing, integration and operational phases, deriving lessons learnt over a variety of different mission types, operator approaches, use cases and environments. Based on these lessons learnt a new generation of propulsion systems is developed, addressing key findings from the large NANO heritage and adding new capabilities, including increased resilience, thrust vector steering and increased power and thrust level. Some of these successor products have already been validated in orbit, including the MICRO R3 and the NANO AR3. While the MICRO R3 features increased power and thrust level, the NANO AR3 is a successor of the heritage NANO thruster with added thrust vectoring capability. 5 NANO AR3 have been launched to date on two different spacecraft. This work presents flight telemetry data of ENPULSION NANO systems and onorbit statistical data of the ENPULSION NANO as well as lessons learnt during onorbit operations, customer assembly, integration and testing support and ground test campaigns conducted at different facilities. We discuss how transfer of lessons learnt and operational improvement across independent missions across customers has been accomplished. Building on these learnings and exhaustive heritage, we present the design of the new generation of propulsion systems that increase the power and thrust level of FEEP systems to address larger spacecraft buses.

Keywords: FEEP, field emission electric propulsion, electric propulsion, flight heritage

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Authors: Amanda C. Evans

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Enabling technologies such as continuous processing (CP) approaches can provide the tools needed to control and manipulate reactivities and transform chemical reactions into micro-controlled in-flow processes. Traditional synthetic approaches can be radically transformed by the application of CP, facilitating the pairing of chemical methodologies with technologies from other disciplines. CP supports sustainable processes that controllably generate reaction specificity utilizing supramolecular interactions. Continuous photochemical processing is an emerging field of investigation. The use of light to drive chemical reactivity is not novel, but the controlled use of specific and tunable wavelengths of light to selectively generate molecular structure under continuous processing conditions is an innovative approach towards chemical synthesis. This investigation focuses on the use of circularly polarized (cp) light as a sustainable catalyst for the CP generation of asymmetric molecules. Chiral photolysis has already been achieved under batch, solid-phase conditions: using synchrotron-sourced cp light, asymmetric photolytic selectivities of up to 4.2% enantiomeric excess (e.e.) have been reported. In order to determine the optimal wavelengths to use for irradiation with cp light for any given molecular building block, CD and anisotropy spectra for each building block of interest have been generated in two different solvents (water, hexafluoroisopropanol) across a range of wavelengths (130-400 nm). These spectra are being used to support a series of CP experiments using cp light to generate enantioselectivity.

Keywords: anisotropy, asymmetry, flow chemistry, active pharmaceutical ingredients

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Authors: Lorna Martha Dreyer

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Consistent with the changing paradigm on the rights of people with disabilities and in pursuit of social justice, there is internationally an increase in students with disabilities enrolling at Higher Education Institutions (HEIs). This trend challenges HEI’s to transform and attain Education for All (EFA) as a global imperative. However, while physical and sensory disabilities are observable, students with specific learning disabilities (SLD) do not present with any visible indications and are often referred to as “hidden” or “invisible” disabilities. This qualitative case study aimed to illuminate the experiences of students with SLDs at a South African university. The research was, therefore, guided by Vygotsky’s social-cultural theory (SCT). This research was conducted within a basic qualitative research methodology embedded in an interpretive paradigm. Data was collected through an online background survey and semi-structured interviews. Thematic qualitative content analysis was used to analyse the collected data systematically. From a social justice perspective, the major findings suggest that there are several factors that impede equal education for students with SLDs at university. Most participants in this small-scale study experienced a lack of acknowledgment and support from lecturers. They reported valuing the support of family and friends more than that of lecturers. It is concluded that lecturers need to be reflective of their pedagogical practices if authentic inclusion is to be realised.

Keywords: higher education, inclusive education, pedagogy, social-cultural theory, specific learning disabilities

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Authors: Nyiko M. Chauke, James Ramontja, Richard M. Moutloali

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The zeolite ZSM-22 material demonstrated effective hydrophilic character as a nanoadditive filler in the preparation of nanocomposite membranes. In this study, nanorods ZSM-22 zeolite materials were hydrothermally synthesised from a homogenous gel mixture prepared using different silica precursors: colloidal silica, fumed silica, tetraethylorthosilicate (TEOS), and aluminium precursor: aluminium sulphate octadecahydrate (Al₂(SO₄)₃.18H₂O to Si/Al of 60. This was focused on developing a defect-free zeolite framework for effective use in applications such as membrane separation process, adsorption, and catalysis. The obtained ZSM-22 zeolite materials with 60 Si/Al ratio exhibits high crystallinity, hydrophilicity, and needle-like morphologies, suggesting successful synthesis as shown by X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier-Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) physicochemical analysis. It was revealed that the use of different nature of silica precursors significantly influenced the properties of the final product and contributed to the development of defect-free zeolite material. As such, the crystalline nanorods of Theta-1 (TON) ZSM-22 obtained from TEOS silica showed high phase purity, defect-free, and narrow particle size distribution. Morphological analysis exhibited that the use of TEOS as silica precursor was effective than its counterparts and produced high crystalline need-like agglomerated particles.

Keywords: silica precursor, hydrothermal synthesis, zeolite material, ZSM-22

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Authors: Y. J. Zhou, G. Lu

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In this paper, an analytical study is made for the dynamic behavior of human brain tissue under transient loading. In this analytical model the Mooney-Rivlin constitutive law is coupled with visco-elastic constitutive equations to take into account both the nonlinear and time-dependent mechanical behavior of brain tissue. Five ordinary differential equations representing the relationships of five main parameters (radial stress, circumferential stress, radial strain, circumferential strain, and particle velocity) are obtained by using the characteristic method to transform five partial differential equations (two continuity equations, one motion equation, and two constitutive equations). Analytical expressions of the attenuation properties for spherical wave in brain tissue are analytically derived. Numerical results are obtained based on the five ordinary differential equations. The mechanical responses (particle velocity and stress) of brain are compared at different radii including 5, 6, 10, 15 and 25 mm under four different input conditions. The results illustrate that loading curves types of the particle velocity significantly influences the stress in brain tissue. The understanding of the influence by the input loading cures can be used to reduce the potentially injury to brain under head impact by designing protective structures to control the loading curves types.

Keywords: analytical method, mechanical responses, spherical wave propagation, traumatic brain injury

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Authors: Nithin Krisshna Gunasekaran, Prathima Prabhu Tumkur, Nicole Nazario Bayon, Krishnan Prabhakaran, Joseph C. Hall, Govindarajan T. Ramesh

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Cerium oxide and turmeric have antioxidant properties, which have gained interest among researchers to study their applications in the field of biomedicine, such asanti-inflammatory, anticancer, and antimicrobial applications. In this study, the turmeric extract was prepared and mixed with cerium nitrate hexahydrate, stirred continuously to obtain a homogeneous solution and then heated on a hot plate to get the supernatant evaporated, then calcinated at 600°C to obtain the cerium oxide nanoparticles. Characterization of synthesized cerium oxide nanoparticles through Scanning Electron Microscopy determined the particle size to be in the range of 70 nm to 250 nm. Energy Dispersive X-Ray Spectroscopy determined the elemental composition of cerium and oxygen. Individual particles were identified through the characterization of cerium oxide nanoparticles using Field Emission Scanning Electron Microscopy, in which the particles were determined to be spherical and in the size of around 70 nm. The presence of cerium oxide was assured by analyzing the spectrum obtained through the characterization of cerium oxide nanoparticles by Fourier Transform Infrared Spectroscopy. The crystal structure of cerium oxide nanoparticles was determined to be face-centered cubic by analyzing the peaks obtained through theX-Ray Diffraction method. The crystal size of cerium oxide nanoparticles was determined to be around 13 nm by using the Debye Scherer equation. This study confirmed the synthesis of cerium oxide nanoparticles using turmeric extract.

Keywords: antioxidant, characterization, cerium oxide, synthesis, turmeric

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Authors: Sabir Hussain, Mujtaba Hassan, Kashif Rasool, Asif Shahzad

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Fine particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) was collected in Islamabad from November 2022 to January 2023, at urban sites. The average mass concentrations of PM2.5 varied, ranging from 90.5 to 133 μg m−3 in urban areas. Environmental scanning electron microscopy (ESEM) analysis revealed that Islamabad's PM2.5 comprised soot aggregates, ashes, minerals, bio-particles, and unidentified particles. Results from inductively coupled plasma atomic emission spectroscopy (ICP-OES) indicated a gradual increase in total elemental concentrations in Islamabad PM2.5 in winter, with relatively high levels in December. Significantly different elemental compositions were observed in urban PM2.5. Enrichment factor (EF) analysis suggested that elements such as K, Na, Ca, Mg, Al, Fe, Ba, and Sr were of natural origin, while As, Cu, Zn, Pb, Cd, Mn, Ni, and Se originated from anthropogenic sources. Plasmid DNA assays demonstrated varying levels of potential toxicity in Islamabad PM2.5 collected from urban sites, as well as across different seasons. Notably, the urban winter PM2.5 sample exhibited much stronger toxicity compared to other samples. The presence of heavy metals in Islamabad PM2.5, including Cu, Zn, Pb, Cd, Cr, Mn, and Ni, may have synergistic effects on human health.

Keywords: islamabad particulate matter pm2.5, scanning electron microscopy with energy-dispersive x-ray spectroscopy(sem-eds), fourier transform infrared spectroscopy(ftir), inductively coupled plasma optical emission spectroscopy(icp-oes)

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Authors: Mujeeb Mohd, Aqil Mohd, A. K. Najmi, Akhtar MMohd, Vasim Mohd

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Dioscorea deltoidea belongs to the Dioscoreaceae family, is usually found in the north-western Himalayas and some other parts of the world up to an altitude of 1000–3000 m. D. deltoidea commonly known as yam and is an extensively used medicinal plant in the indigenous system of medicine. It has been reported to contain dioscine a steroidal glycoside in higher concentration. In the present investigation, silver nanoparticles (AgNPs) have been synthesized by a simple, efficient, environmentally benevolent and economic microwave-assisted method. Callus culture of D. deltoidea was developed and maintained on Murashige and skooge basal medium supplemented with different combination and concentration of plant growth regulators. Aqueous extract of callus culture was used as the reducing and stabilizing agent. The synthesized nanoparticles have been characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD analysis. The presence of a characteristic surface plasmon resonance (SPR) absorption band at 430 nm in UV–Vis reveals the reduction of silver metal ions into silver nanoparticles. Whereas FTIR analysis was performed to probe the possible functional group involved in the synthesis of AgNPs. Further extract and AgNPs were evaluated for antimicrobial activity against different pathogenic microorganisms.

Keywords: antimicrobial, Dioscorea deltoidea, microwave, silver, nanoparticles

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Authors: Sam Bahreini, Payam Hayati

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Metal-organic coordination [Cu(L)₄(SCN)₂] was synthesized applying ultrasonic irradiation, and its photocatalytic performance for the degradation of Remdesivir (RS) under sunlight irradiation was systematically explored for the first time in this study. The physicochemical properties of the synthesized photocatalyst were investigated using Fourier-transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), powder x-ray diffraction (PXRD), energy-dispersive x-ray (EDX), thermal gravimetric analysis (TGA), diffuse reflectance spectroscopy (DRS) techniques. Systematic examinations were carried out by changing irradiation time, temperature, solution pH value, contact time, RS concentration, and catalyst dosage. The photodegradation kinetic profiles were modeled in pseudo-first order, pseudo-second-order, and intraparticle diffusion models reflected that photodegradation onto [Cu(L)₄(SCN)₂] catalyst follows pseudo-first order kinetic model. The fabricated [Cu(L)₄(SCN)₂] nanostructure bandgap was determined as 2.60 eV utilizing the Kubelka-Munk formula from the diffuse reflectance spectroscopy method. Decreasing chemical oxygen demand (COD) (from 70.5 mgL-1 to 36.4 mgL-1) under optimal conditions well confirmed mineralizing of the RS drug. The values of ΔH° and ΔS° was negative, implying the process of adsorption is spontaneous and more favorable in lower temperatures.

Keywords: Photocatalytic degradation, COVID-19, density functional theory (DFT), molecular electrostatic potential (MEP)

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Authors: M. Jerold, V. Sivasubramanian

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This study reports the removal of Malachite Green (MG) from simulated wastewater by using marine macro algae Ulva lactuca. Batch biosorption experiments were carried out to determine the biosorption capacity. The biosorption capacity was found to be maximum at pH 10. The effect of various other operation parameters such as biosorbent dosage, initial dye concentration, contact time and agitation was also investigated. The equilibrium attained at 120 min with 0.1 g/L of biosorbent. The isotherm experimental data fitted well with Langmuir Model with R² value of 0.994. The maximum Langmuir biosorption capacity was found to be 76.92 mg/g. Further, Langmuir separation factor RL value was found to be 0.004. Therefore, the adsorption is favorable. The biosorption kinetics of MG was found to follow pseudo second-order kinetic model. The mechanistic study revealed that the biosorption of malachite onto Ulva lactuca was controlled by film diffusion. The solute transfer in a solid-liquid adsorption process is characterized by the film diffusion and/or particle diffusion. Thermodynamic study shows ΔG° is negative indicates the feasibility and spontaneous nature for the biosorption of malachite green. The biosorbent was characterized using Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and elemental analysis (CHNS: Carbon, Hydrogen, Nitrogen, Sulphur). This study showed that Ulva lactuca can be used as promising biosorbent for the removal of MG from wastewater.

Keywords: biosorption, Ulva lactuca, wastewater, malachite green, isotherm, kinetics

Procedia PDF Downloads 137

Authors: Raghvendra Singh Yadav, Ivo Kuřitka, Jarmila Vilcakova, Jaromir Havlica, Lukas Kalina, Pavel Urbánek, Michal Machovsky, Milan Masař, Martin Holek

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In this work, CoFe₂₋ₓGdₓO₄ (x=0.00, 0.05, 0.10, 0.15, 0.20) spinel ferrite nanoparticles are synthesized by sonochemical method. The structural properties and cation distribution are investigated using X-ray Diffraction (XRD), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray photoelectron spectroscopy. The morphology and elemental analysis are screened using field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy, respectively. The particle size measured by FE-SEM and XRD analysis confirm the formation of nanoparticles in the range of 7-10 nm. The electrical properties show that the Gd³⁺ doped cobalt ferrite (CoFe₂₋ₓGdₓO₄; x= 0.20) exhibit enhanced dielectric constant (277 at 100 Hz) and ac conductivity (20.17 x 10⁻⁹ S/cm at 100 Hz). The complex impedance measurement study reveals that as Gd³⁺ doping concentration increases, the impedance Z’ and Z’ ’ decreases. The influence of Gd³⁺ doping in cobalt ferrite nanoparticles on the magnetic property is examined by using vibrating sample magnetometer. Magnetic property measurement reveal that the coercivity decreases with Gd³⁺ substitution from 234.32 Oe (x=0.00) to 12.60 Oe (x=0.05) and further increases from 12.60 Oe (x=0.05) to 68.62 Oe (x=0.20). The saturation magnetization decreases with Gd³⁺ substitution from 40.19 emu/g (x=0.00) to 21.58 emu/g (x=0.20). This decrease follows the three-sublattice model suggested by Yafet-Kittel (Y-K). The Y-K angle increases with the increase of Gd³⁺ doping in cobalt ferrite nanoparticles.

Keywords: sonochemical method, nanoparticles, magnetic property, dielectric property, electrical property

Procedia PDF Downloads 337

Authors: Adel A. Ghobbar, Varun Raman

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The Corrective maintenance of components and systems is a problem plaguing almost every industry in the world today. Train operators’ and the maintenance repair and overhaul subsidiary of the Dutch railway company is also facing this problem. A considerable portion of the maintenance activities carried out by the company are unscheduled. This, in turn, severely stresses and stretches the workforce and resources available. One possible solution is to have a robust preventive maintenance plan. The other possible solution is to plan maintenance based on real-time data obtained from sensor-based ‘Health and Usage Monitoring Systems.’ The former has been investigated in this paper. The preventive maintenance model developed for train operator will subsequently be extended, to tackle the unscheduled maintenance problem also affecting the aerospace industry. The extension of the model to the aerospace sector will be dealt with in the second part of the research, and it would, in turn, validate the soundness of the model developed. Thus, there are distinct areas that will be addressed in this paper, including the mathematical modelling of preventive maintenance and optimization based on cost and system availability. The results of this research will help an organization to choose the right maintenance strategy, allowing it to save considerable sums of money as opposed to overspending under the guise of maintaining high asset availability. The concept of delay time modelling was used to address the practical problem of unscheduled maintenance in this paper. The delay time modelling can be used to help with support planning for a given asset. The model was run using MATLAB, and the results are shown that the ideal inspection intervals computed using the extended from a minimal cost perspective were 29 days, and from a minimum downtime, perspective was 14 days. Risk matrix integration was constructed to represent the risk in terms of the probability of a fault leading to breakdown maintenance and its consequences in terms of maintenance cost. Thus, the choice of an optimal inspection interval of 29 days, resulted in a cost of approximately 50 Euros and the corresponding value of b(T) was 0.011. These values ensure that the risk associated with component X being maintained at an inspection interval of 29 days is more than acceptable. Thus, a switch in maintenance frequency from 90 days to 29 days would be optimal from the point of view of cost, downtime and risk.

Keywords: delay time modelling, unscheduled maintenance, reliability, maintainability, availability

Procedia PDF Downloads 119

Authors: Maha Al-Ali, Selvakannan Periasamy, Rajarathinam Parthasarathy

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Drying temperature is an important factor impacting the physicochemical properties of the dried materials, particularly the pharmaceutical powders. Drying of pharmaceuticals by using microwave radiation is very limited, and the available information about the interaction between the electromagnetic radiations and the pharmaceutical material is still scarce. Therefore, microwave drying process is employed in this work to dry the wet (moisturised) granules of the formulated naproxen-sodium drug. This study aims to investigate the influences of the microwave radiation temperatures on the moisture removal, the crystalline structure, the size and morphology of the dried naproxen-sodium particles, and identify any potential changes in the chemical groups of the drug. In this work, newly formulated naproxen-sodium is prepared and moisturized by wet granulation process and hence dried by using microwave radiation at different temperatures. Moisture analyzer, Fourier-transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscope are used to characterise the non-moisturised powder (reference powder), the moisturised granules, and the dried particles. The results show that microwave drying of naproxen-sodium at high drying temperature is more efficient than that at low temperatures in terms of the moisture removal. Although there is no significant change in the chemical structure of the dried particles, the particle size, crystallinity and morphology are relatively changed with changing of heating temperature.

Keywords: heating temperature, microwave drying, naproxen-sodium, particle size

Procedia PDF Downloads 143

Authors: S. Sharma, U. Batra, S. Kapoor, A. Dua

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In this study, the effects and interactions of reaction time and capping agent assistance during sol-gel synthesis of magnesium substituted hydroxyapatite nanopowder (MgHA) on hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) ratio, Ca/P ratio and mean crystallite size was examined experimentally as well as through statistical analysis. MgHA nanopowders were synthesized by sol-gel technique at room temperature using aqueous solution of calcium nitrate tetrahydrate, magnesium nitrate hexahydrate and potassium dihydrogen phosphate as starting materials. The reaction time for sol-gel synthesis was varied between 15 to 60 minutes. Two process routes were followed with and without addition of triethanolamine (TEA) in the solutions. The elemental compositions of as-synthesized powders were determined using X-ray fluorescence (XRF) spectroscopy. The functional groups present in the as-synthesized MgHA nanopowders were established through Fourier Transform Infrared Spectroscopy (FTIR). The amounts of phases present, Ca/P ratio and mean crystallite sizes of MgHA nanopowders were determined using X-ray diffraction (XRD). The HA content in biphasic mixture of HA and β-TCP and Ca/P ratio in as-synthesized MgHA nanopowders increased effectively with reaction time of sols (p < 0.0001, two way Anova), however, these were independent of TEA addition (p > 0.15, two way Anova). The MgHA nanopowders synthesized with TEA assistance exhibited 14 nm lower crystallite size (p < 0.018, 2 sample t-test) compared to the powder synthesized without TEA assistance.

Keywords: capping agent, hydroxyapatite, regression analysis, sol-gel, 2- sample t-test, two-way analysis of variance (ANOVA)

Procedia PDF Downloads 355

Authors: Vinda B. Manurung, Laila Warkhaida, David Hutabarat, Sentanu Wisnuwardhana, Christovik Simatupang, Dhani Sanjaya, Ashadi, Redha B. Putra, Kiki Yustendi

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The geothermal drilling environment presents many obstacles that have limited the use of directional drilling and logging-while-drilling (LWD) technologies, such as borehole washout, mud losses, severe vibration, and high temperature. The case study presented in this paper demonstrates a practice to enhance data logging in geothermal drilling by deploying advanced telemetry and LWD technologies. This operation is aiming continuous improvement in geothermal drilling operations. The case study covers a 12.25-in. hole section of well XX-05 in Pad XX of the Sorik Marapi Geothermal Field. LWD string consists of electromagnetic (EM) telemetry, pressure while drilling (PWD), vibration (DDSr), and acoustic calliper (ACAL). Through this tool configuration, the operator acquired drilling mechanics and caliper logs in real-time and recorded mode, enabling effective monitoring of wellbore stability. Throughout the real-time acquisition, EM-PPM telemetry had provided a three times faster data rate to the surface unit. With the integration of Caliper data and Drilling mechanics data (vibration and ECD -equivalent circulating density), the borehole conditions were more visible to the directional driller, allowing for better control of drilling parameters to minimize vibration and achieve optimum hole cleaning in washed-out or tight formation sequences. After reaching well TD, the recorded data from the caliper sensor indicated an average of 8.6% washout for the entire 12.25-in. interval. Washout intervals were compared with loss occurrence, showing potential for the caliper to be used as an indirect indicator of fractured intervals and validating fault trend prognosis. This LWD case study has given added value in geothermal borehole characterization for both drilling operation and subsurface. Identified challenges while running LWD in this geothermal environment need to be addressed for future improvements, such as the effect of tool eccentricity and the impact of vibration. A perusal of both real-time and recorded drilling mechanics and caliper data has opened various possibilities for maximizing sensor usage in future wells.

Keywords: geothermal drilling, geothermal formation, geothermal technologies, logging-while-drilling, vibration, caliper, case study

Procedia PDF Downloads 109

Authors: Gina Zavaleta-Espejo, Segundo R. Jáuregui-Rosas, Fanny V. Samanamud-Moreno, José Saldaña Jiménez, Anibal Felix-Quintero, Víctor Montero-Del Aguila, Elsi Mejía-Uriarte

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Vicugnapacos "alpaca" fabrics are considered special for their finesse, and the garments in the textile market are very luxurious. It has many special characteristics such as antiallergic, soft, hygroscopic, among others. In this sense, the research aimed to evaluate the antimicrobial activity of alpaca fabrics functionalized with silver nanoparticles on the bacteria Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. For the functionalization of the fabrics, AgNO3 and different concentrations of trisodium citrate (TSC) 2, 6, and 10 mg. Tissue characterization was performed using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The determination of the antimicrobial activity of the alpaca tissues was made by the Kirby-Bauer method with alpaca tissue discs functionalized with silver nanoparticles, an experimental design was made in completely randomized blocks with three treatments and a negative control with three repetitions. The results showed that inhibition halos were formed for both bacteria, therefore, the functionalized tissues have a high antimicrobial activity, whose mechanism of action is attributed to the free radicals (ROS) generated by the nanoparticles that cause oxidative damage to the bacteria. proteins and lipids of the bacterial cell wall.

Keywords: antimicrobial, animal fibers, fabrics, functionalization, trisodium citrate

Procedia PDF Downloads 124

Authors: K. Umbleja, M. Ichino

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Symbolic data mining has been developed to analyze data in very large datasets. It is also useful in cases when entry specific details should remain hidden. Symbolic data mining is quickly gaining popularity as datasets in need of analyzing are becoming ever larger. One type of such symbolic data is a histogram, which enables to save huge amounts of information into a single variable with high-level of granularity. Other types of symbolic data can also be described in histograms, therefore making histogram a very important and general symbolic data type - a method developed for histograms - can also be applied to other types of symbolic data. Due to its complex structure, analyzing histograms is complicated. This paper proposes a method, which allows to compare two histogram-valued variables and therefore find a dissimilarity between two histograms. Proposed method uses the Ichino-Yaguchi dissimilarity measure for mixed feature-type data analysis as a base and develops a dissimilarity measure specifically for histogram data, which allows to compare histograms with different number of bins and bin widths (so called general histogram). Proposed dissimilarity measure is then used as a measure for clustering. Furthermore, linkage method based on weighted averages is proposed with the concept of cluster compactness to measure the quality of clustering. The method is then validated with application on real datasets. As a result, the proposed dissimilarity measure is found producing adequate and comparable results with general histograms without the loss of detail or need to transform the data.

Keywords: dissimilarity measure, hierarchical clustering, histograms, symbolic data analysis

Procedia PDF Downloads 149