Search results for: literature review software

Authors: Chih-Yuan Weng

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It may be a common sense that indigenous people in Taiwan, like their counterparts in the rest of the world, are generally more disadvantaged than other citizens in terms of all sorts of socioeconomic indicators. However, it has also been well-documented in the literature that there is always significant variation in the level of indigenous poverty, both among individuals and among tribes, which can be obscured by a national survey that does not take into account the heterogeneity, such as tribal locations, among indigenous people. Thus, using a Truku tribe in a remote county of Taiwan (i.e., Hualien County) as an example, this study aims at investigating whether and how the socioeconomic livelihood of the indigenous residents would be damaged by the remoteness of their tribal community.

Keywords: indigenous people, tribal community, poverty, socioeconomic livelihood, remoteness

Procedia PDF Downloads 87

Authors: M. Al-Roumi, A. Al-Yaqout, A. Al-Baz

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Recently, sea cucumbers have shown to be significant to global trade and incomes due to their high commercial value for the pharmaceutical and cosmetics industry. This rising demand for sea cucumber products has created increasing harvest stress on the natural populations and led to the depletion of sea cucumbers stocks worldwide and accordingly there is a big concern on the marine environment's health worldwide. Few species have been reported and identified via morophlogical features only. Several sea cucumber species were collected from the North West side reefs at Qaruh Island, and the north side of Umm Al-Maradem Island in Kuwait waters, in the north-western Arabian Gulf, in order to identify the sea cucumber species available in the Kuwaiti waters. The identified species were Holothuria atra, Holothuria arenicola, Holothuria hilla and Holothuria impatiens. Species identification was made using morphological keys and review of their ossicles. This paper reports the species Stichopus hermanni from Kuwait.

Keywords: Stichopus hermanni, Kuwait waters, Arabian Gulf, ossicles

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Authors: Zohra Aziz Ali Manjiyani, Renju Thomas Jacob, Keerthan Kumar

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This project develops a hand movement monitoring system, which feeds the data into the computer and gives the 3D image rotation according to the direction of the tilt and hence monitoring the movement of the hand in context to its tilt. Advancement of MEMS Technology has enabled us to get very small and low-cost accelerometer ICs which is based on capacitive principle. Accelerometer based Tilt sensor ADXL335 is used in this paper, based on MEMS technology and the project emphasis on the development of the MEMS-based accelerometer to measure the tilt, interfacing the hardware with the LabVIEW and showing the 3D rotation to the user, which is in his understandable form and tilt data can be saved in the computer. It provides an experience of working on emerging technologies like MEMS and design software like LabVIEW.

Keywords: MEMS accelerometer, tilt sensor ADXL335, LabVIEW simulation, 3D animation

Procedia PDF Downloads 522

Authors: Mohammad Ibrahim

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The study was conducted at Albasar international foundation ophthalmic hospitals in Sudan to study the burden and patterns of ophthalmic disorder in the sector. Review of the hospitals records revealed that the total number of patient examined in the hospitals and outreached camps conducted by the hospitals is 10,513,874, the total number of surgeries is 694,015 and the total number of pupils at school program is 230,382. The organization working with the highest management system and standards and quality result based planning. The study yielded that the ophthalmic problem in Sudan are of great percentage and the temporal blindness disorder are high since major cases and surgeries were Cataract (57.8%). Retinal problem (2.9%), Glaucoma (2.4%), Orbit and Occulo-plastic disorders (2.2%) other disorders are refractive errors, squint and strabismus, Corneal, Pediatrics and minor ophthalmic disorders.

Keywords: hospitals and outreach ophthalmic services, largest coverage of ophthalmic services, nonprofitable ophthalmic services, strong management system and standards

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Authors: R. M. Rizk-Allah

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This paper presents co-evolutionary fruit fly optimization algorithm based on firefly algorithm (CFOA-FA) for solving unconstrained optimization problems. The proposed algorithm integrates the merits of fruit fly optimization algorithm (FOA), firefly algorithm (FA) and elite strategy to refine the performance of classical FOA. Moreover, co-evolutionary mechanism is performed by applying FA procedures to ensure the diversity of the swarm. Finally, the proposed algorithm CFOA- FA is tested on several benchmark problems from the usual literature and the numerical results have demonstrated the superiority of the proposed algorithm for finding the global optimal solution.

Keywords: firefly algorithm, fruit fly optimization algorithm, unconstrained optimization problems

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Authors: Vinod Kumar, Arun Kumar, Surjit Angra

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This paper addresses the junction stress analysis of orthogonally intersecting thin walled cylindrical shell and thin walled cylindrical nozzle subjected to external loading on nozzle. Junction stresses have been calculated theoretically by welding research council (WRC) bulletins 107 and 297 for different nozzle loads. WRC bulletins 107 and 297 have been used by design engineers for calculating nozzle-vessel junction stresses since their publication. They give simple empirical relations and easy in application. Also 3D FEA in which material is elastic has been done in ANSYS software with 8 node solid element model and results of FEA have been compared with WRC results. Stress intensities obtained by WRC 297 are generally slightly higher than obtained by WRC 107. Membrane stresses obtained by FEA are much higher than WRC and membrane plus bending stresses obtained by FEA are lower than WRC.

Keywords: FEA, junction stress, solid element, WRC 107, WRC 297

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Authors: F. Boudet, V. Galano, D. Gmira, L. Munoz, A. Reina

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Commodities pricing needs a specific approach as they are often linked to each other and so are expectedly doing their prices. They are called co-integrated when at least one stationary linear combination exists between them. Though widespread in economic literature, and even if many equilibrium relations and co-movements exist in the economy, this principle of co-movement is not developed in derivatives field. The present study focuses on the following problem: How can the price of a forward agreement on a commodity be simulated, when it is co-integrated with other ones? Theoretical analysis is developed from Gibson-Schwartz model and an analytical solution is given for short maturities contracts and under risk-neutral conditions. The application has been made to crude oil and heating oil energy commodities and result confirms the applicability of proposed method.

Keywords: co-integration, commodities, forward pricing, Gibson-Schwartz

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Authors: Shiva Subhedar, Abhishek Jain, Shivin Mittal

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Icons are not merely decorative elements in enterprise applications but very often used because of their many advantages such as compactness, visual appeal, etc. Despite these potential advantages, icons often cause usability problems when they are designed without consideration for their many potential downsides. The aim of the current study was to examine the effect of articulatory distance – the distance between the physical appearance of an interface element and what it actually means. In other words, will the subject find the association of the function and its appearance on the interface natural or is the icon difficult for them to associate with its function. We have calculated response time and quality of identification by varying icon concreteness, the context of usage and subject experience in the enterprise context. The subjects were asked to associate icons (prepared for study purpose) with given function options in context and out of context mode. Response time and their selection were recorded for analysis.

Keywords: HCI, icons, icon concreteness, icon recognition

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Authors: K. Matušínská, Z. Bednarčík, M. Klepek

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This paper examines international marketing in business practice of Czech exporting small and medium-sized enterprises (SMEs) with regard to the strategic perspectives. Research was focused on Czech exporting SMEs from Moravian-Silesia region and their behaviour on international markets. For purpose of collecting data, a questionnaire was given to 262 SMEs involved in international business. Statistics utilized in this research included frequency, mean, percentage, and chi-square test. Data were analysed by Statistical Package for the Social Sciences software. The research analysis disclosed that there is certain space for improvement in strategic marketing especially in marketing research, perception of cultural and social differences, product adaptation and usage of marketing communication tools.

Keywords: international marketing, marketing mix, marketing research, small and medium-sized enterprises, strategic marketing

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Authors: Ahmad Saadiq, Neeraj Sahu

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The partial or full replacement of natural coarse aggregate by recycled concrete aggregate (RCA) is of great benefit to the environment, as the demand of natural coarse aggregate reduces. In the modern construction and practice, the use of RCA is limited to backfilling and road construction. The establishment of RCA for its wide application can only be done after having an understanding of the use of RCA in conventional concrete. To have an insight to this, various tests to determine the compressive strength, elastic strength, workability, durability and drying shrinkage tests can be done and the test results may be different from that obtained from natural coarse aggregates, by using natural coarse aggregate in concrete. This paper gives a comprehensive review of the said tests done on RCA concrete. The results obtained from the tests indicate that RCA concrete gives comparable compressive strength, stiffness, and workability relative to the corresponding results obtained from the natural coarse aggregates. However, the durability and drying shrinkage had more variance but well within recommended limits.

Keywords: aggregate, compressive strength, durability, modulus of elasticity, recycled concrete, shrinkage, workability

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Authors: Awais Asif

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This article investigates fixed point theorems of Chatterjea type F-contraction in the setting of F-metric space. We relax the conditions of F-contraction and define modified F-contraction for two mappings. The study provides fixed point results for both single-valued and multivalued mappings. The results are further extended to common fixed point theorems for two mappings. Moreover, to discuss the applicability of our results, an application is provided, which shows the role of our results in finding the solution to functional equations in dynamic programming. Our results generalize and extend the existing results in the literature.

Keywords: Chatterjea type F-contraction, F-cauchy sequence, F-convergent, multi valued mappings

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Authors: Masoumeh Pirhadi

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Air pollution is becoming a major health problem affecting millions. In support of this observation, the world health organization estimates that many people feel unhealthy due to pollution. This is a coupled fact that one of the main global sources of air pollution in cities is greenhouse gas emissions due heavy traffic. Green walls are developed as a sustainable strategy to reduce pollution by increasing vegetation in developed areas without occupying space in the city. This concept an offer advantageous environmental benefits and they can also be proposed for aesthetic purposes, and today they are used to preserve the urban environment. Green walls can also create environments that can promote a healthy lifestyle. Findings of multiple studies also indicate that Green infrastructure in cities is a strategy for improving air quality and increasing the sustainability of cities. Since these green solutions (green walls) act as porous materials that affect the diffusion of air pollution they can also act as a removing air vents that clean the air. Therefore, implementation of this strategy can be considered as a prominent factor in achieving a cleaner environment.

Keywords: green vegetation, air pollution, green wall, urban area

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Authors: J. L. Andrade-Pineda, J.M. León-Blanco, M. Calle, P. L. González-R

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The enrollment in current Master's degree programs usually pursues gaining the expertise required in real-life workplaces. The experience we present here concerns the learning process of "Project Management Methodology (PMM)", around a cooperative/collaborative mechanism aimed at affording students measurable learning goals and providing the teacher with the ability of focusing on the weaknesses detected. We have designed a mixed summative/formative evaluation, which assures curriculum engage while enriches the comprehension of PMM key concepts. In this experience we converted the students into active actors in the evaluation process itself and we endowed ourselves as teachers with a flexible process in which along with qualifications (score), other attitudinal feedback arises. Despite the high level of self-affirmation on their discussion within the interactive assessment sessions, they ultimately have exhibited a great ability to review and correct the wrong reasoning when that was the case.

Keywords: cooperative-collaborative learning, educational management, formative-summative assessment, leadership training

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Authors: Peter Lindstrom, Caroline Gyberg, Scott Goodwin

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The Swedish police organisation was fundamentally reorganized in 2015 when 21 regional police forces were combined into one national police authority divided in 7 larger police regions, 35 police areas, and some 100 local police districts. A central theme for the reform was that local crime prevention policing should be more unified in the country. In this paper, we review crime prevention strategies in Sweden from a criminological and policing perspective focusing, among other things, on differences between urban and rural areas. In the crime prevention field, words such as 'knowledge- and evidence-based', 'collaboration', and 'strategies' are common. Our objective is to investigate the relationship between theoretical and practical knowledge in local crime prevention work. Our research indicate that an elaborated and strategic connection between theoretical and practical perspectives is important for successful local crime prevention work. Universities may provide a platform such knowledge exchange.

Keywords: crime prevention, police reform, urban and rural areas, criminological and policing perspectives

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Authors: Ashish Kumar, Kaptan Singh, Amit Saxena

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Today, it is believed that crimes have the greatest impact on a person's ability to progress financially and personally. Identifying places where individuals shouldn't go is crucial for preventing crimes and is one of the key considerations. As society and technologies have advanced significantly, so have crimes and the harm they wreak. When there is a concentration of people in one place and changes happen quickly, it is even harder to prevent. Because of this, many crime prevention strategies have been embraced as a component of the development of smart cities in numerous cities. However, crimes can occur anywhere; all that is required is to identify the pattern of their occurrences, which will help to lower the crime rate. In this paper, an analysis related to crime has been done; information related to crimes is collected from all over India that can be accessed from anywhere. The purpose of this paper is to investigate the relationship between several factors and India's crime rate. The review has covered information related to every state of India and their associated regions of the period going in between 2001- 2014. However various classes of violations have a marginally unique scope over the years.

Keywords: K-nearest neighbor, random forest, decision tree, pre-processing

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Authors: Veysel Seker

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Graphic designing and virtual reality have been affected by digital development and technological development for the last decades. This study aims to compare and evaluate digitalization and virtual reality evaluation in traditional and classical methods of the graphic designing sector in Turkey. The qualitative and quantitative studies and research were discussed and identified according to the evaluated results of the literature surveys. Moreover, the study showed that the competency gap between graphic design schools and the field should be determined and well-studied. The competencies of traditional graphic designers will have a big challenge for the purpose of the transition into the developed and evaluated digital graphic design world.

Keywords: digitalization, evaluation, graphic designing, virtual reality

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Authors: Rhaptyalyani Herno Della, Nyimas Septi Rika Putri, Rika Nabila

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The growth of population and economic activities in urban areas needs support economic development, needs to be balanced with adequate environmental infrastructure development. Settlement can avoid from rundown condition and uninhabitable if the development of urban area accordance with healthy development. Identifying database of slum in this study reference to the Review of the Spatial Plan Development of Palembang City, Laws of Public Works Department about Technical Guidelines on the Quality Improvement Housing and Slum and Urban Spatial Global Report on Human Settlements 2003. A case study for identifying in Palembang riverbanks area are located in two districts; Ilir Timur I and Ilir Timur II. This study do the identification of slum areas based on several variables about physical and non physical aspect, then the result of identification are used to define a policy that can be used to improve the area.

Keywords: slum, riverbanks area, urban area, infrastructure

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Authors: B. Zare-Farsani, M. Valieghbal, M. Tarkashvand, A. H. Farahbod

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To provide the conditions for nuclear fusion by high energy and powerful laser beams, it is required to have a high degree of symmetry and surface uniformity of the spherical capsules to reduce the Rayleigh-Taylor hydrodynamic instabilities. In this paper, we have used the digital microscopic holography based on Mach-Zehnder interferometer to study the quality of targets for inertial fusion. The interferometric pattern of the target has been registered by a CCD camera and analyzed by Holovision software. The uniformity of the surface and shell thickness are investigated and measured in reconstructed image. We measured shell thickness in different zone where obtained non uniformity 22.82 percent.  

Keywords: inertial confinement fusion, mach-zehnder interferometer, digital holographic microscopy, image reconstruction, holovision

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Authors: Nabil Mohammed Nasser Salem

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International advertisements targeting the Arab world are usually modified to be compatible with the conservative culture in many Arab countries. The portrayal of female models in international advertisements in Arab magazines avoids direct sexual representation. Arab culture is guided by religious teachings and social restrictions that prohibit the display of many parts of the female body. Exposure of shoulders, arms, armpits, cleavage, legs, thighs, etc., of the female body is usually avoided in international advertisements published in Arab magazines. Exposure to parts of the female body other than the face and hands may be considered offensive in many parts of Arab countries. Although extensive research has been conducted on Arabic advertisements, to our best knowledge, there are no publications in the literature that address the recent changes in the visual sign system in international advertisements in Arab magazines using semiotics as a research method. The present study aims to analyze the changes in the visual sign system of international advertisements published in Arab magazines that promote female fragrances. It tries to analyze the differences in the sexual representations of the same female models in some selected advertisements during different periods. The magazines are randomly selected from the period between 2000 and 2019. The selection of magazines is based on their availability and popularity. The study focuses on the Dior Jadore ads because they reflect important changes in the appearance of the same female model between 2000 to 2019. The result of the study shows important changes in the sexual representation of the same female body. The Dior Jadore advertisement in 2000 shows only the head of the female model. The model is modestly portrayed and shows clear cultural and religious restrictions on the sexual representation of the female body. The result shows that the same female model is portrayed differently in the Dior Jadore advertisement from the period 2005 to 2019. These versions of advertisements show more parts of the female body that are covered in the older versions and show stronger sexual representations. The study is an important contribution as it fills an important gap in the literature by extending semiotic research to the study of recent visual changes in the sign system of international advertisements published in Arab magazines during an important period in the history of international advertisement targeting the Arab world, as they reflect changes in the sexual representation of female models.

Keywords: Arab magazine, female body, international advertisements, semiotics, sexual representation

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Authors: Mokhtar Nikgoo

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Road definition and road construction: in engineering literature, a road is defined as a means of communication between two different places by air, land, and sea. In this way, all sea, land, and air routes are considered as roads. Road construction is an operation to create a road on the ground between 2 points with a specified width, which includes works such as subgrade, paving, placing tables, and traffic signs on the road. In this article, the stages of road construction are explained from the beginning to the end. Road construction is generally done in the construction of rural, urban, and inter-city roads, and according to the special conditions of this area, the precision of engineers in its design and calculations is very important. For example, if the design of a road does not pay enough attention to the way the road curves, there will undoubtedly be countless accidents. Also, adjusting the road surface and its durability and uniformity are among the things that engineers solve according to the upcoming obstacles.

Keywords: road construction, surveying, freeway, pavement, excavator

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Authors: Baeza S. Roberto

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The knitted fabric suffers a deformation in its dimensions due to stretching and tension factors, transverse and longitudinal respectively, during the process in rectilinear knitting machines so it performs a dry relaxation shrinkage procedure and thermal action of prefixed to obtain stable conditions in the knitting. This paper presents a dry relaxation shrinkage prediction of Bordeaux fiber using a feed forward neural network and linear regression models. Six operational alternatives of shrinkage were predicted. A comparison of the results was performed finding neural network models with higher levels of explanation of the variability and prediction. The presence of different reposes are included. The models were obtained through a neural toolbox of Matlab and Minitab software with real data in a knitting company of Southern Guanajuato. The results allow predicting dry relaxation shrinkage of each alternative operation.

Keywords: neural network, dry relaxation, knitting, linear regression

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Authors: Siti Nadiah Nuwawi, Roshidah Hassan

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Dialect is one of the language variants emerge due to certain factors. One of the distinctive dialects spoken by people in Malaysia is the one spoken by those who reside in the inland area of the East Peninsular Malaysia; Hulu Terengganu, which is known as Ulu Terengganu Malay dialect. This dialect is unique since it possesses ancient elements in its phonology elements, which makes it is hard to be understood by people who come from other states. There is dearth of acoustic studies of the dialect in which this paper aims to attain by describing the quality of the monophthongs found in the dialect instrumentally based on their first and second formant values. The hertz values are observed and recorded from the waveforms and spectrograms depicted in PRAAT version 6.0.43 software. The findings show that Ulu Terengganu Malay speakers produced ten monophthongs namely /ɛ/, /e/, /a/, /ɐ/, /ɞ/, /ɔ/, /i/, /o/, /ɵ/ and /ɘ/ which applauds a few monophthongs suggested by past researchers which were based on auditory impression namely /ɛ/, /e/, /a/, ɔ/, and /i/. It also discovers the other five monophthongs of the dialect which are unknown before namely /ɐ/, /ɞ/, /o/, /ɵ/ and /ɘ/.

Keywords: acoustic analysis, dialect, formant values, monophthongs, Ulu Terengganu Malay

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Authors: Tianyu Gao

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Digital architectures use computer-aided design, programming, simulation, and imaging to create virtual forms and physical structures. Today's customers want to know more about their buildings. They want an automatic thermostat to learn their behavior and contact them, such as the doors and windows they want to open with a mobile app. Therefore, the architectural display form is more closely related to the customer's experience. Based on the purpose of building informationization, this paper studies the steel structure design based on BIM. Taking the Zigan office building in Hangzhou as an example, it is divided into four parts, namely, the digital design modulus of the steel structure, the node analysis of the steel structure, the digital production and construction of the steel structure. Through the application of BIM software, the architectural design can be synergized, and the building components can be informationized. Not only can the architectural design be feedback in the early stage, but also the stability of the construction can be guaranteed. In this way, the monitoring of the entire life cycle of the building and the meeting of customer needs can be realized.

Keywords: digital architectures, BIM, steel structure, architectural design

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Authors: Han-Taw Chen, Chung-Hou Lai, Tzu-Hsiang Lin, Ge-Jang He

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This study applies the inverse method and three-dimensional CFD commercial software in conjunction with the experimental temperature data to investigate the heat transfer and fluid flow characteristics of the plate-fin heat sink in a closed rectangular enclosure for various values of fin height. The inverse method with the finite difference method and the experimental temperature data is applied to determine the heat transfer coefficient. The k-ε turbulence model is used to obtain the heat transfer and fluid flow characteristics within the fins. To validate the accuracy of the results obtained, the comparison of the average heat transfer coefficient is made. The calculated temperature at selected measurement locations on the plate-fin is also compared with experimental data.

Keywords: inverse method, FLUENT, k-ε model, heat transfer characteristics, plate-fin heat sink

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Authors: Geoff Skinner, Ilung Pranata

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The advancement of ICT innovations provides us with a comfortable and convenient modern lifestyle. However, this modern easy lifestyle is proving to have some serious health consequences. Such technological advancements that have dramatically increased ones time in front of screens have been a contributing factor to increasing rates of obesity. In particular the youth obesity issue has gained more and more attention from researchers and health institutions around the world. Although technology innovations may lead to a sedate modern life, they also have a potential to solve the obesity issue in children. This paper provides a review of the issues in child obesity and the potential of active video games to mitigate these issues. Additionally, the paper also discusses the key requirements to develop an active video game that hopes to help combat child obesity through motivating youth to exergame. A framework is introduced to meet the requirements, from which a prototype was implemented. Discussion of the simulation and testing that were performed to verify the attainment of objectives is also detailed.

Keywords: e-video games, exergaming, health informatics, human computer interaction

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Authors: R. Rama Kishore, Sunesh

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Recent development in the usage of internet for different purposes creates a great threat for the copyright protection of the digital images. Digital watermarking can be used to address the problem. This paper presents detailed review of the different watermarking techniques, latest trends in the field of secured, robust and imperceptible watermarking. It also discusses the different optimization techniques used in the field of watermarking in order to improve the robustness and imperceptibility of the method. Different measures are discussed to evaluate the performance of the watermarking algorithm. At the end, this paper proposes a watermarking algorithm using (2, 2) share visual cryptography and Bezier curve based algorithm to improve the security of the watermark. The proposed method uses fractional transformation to improve the robustness of the copyright protection of the method. The algorithm is optimized using fuzzy entropy for better results.

Keywords: digital watermarking, fractional transform, visual cryptography, Bezier curve, fuzzy entropy

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Authors: Gerald S. Atchaso, Erwin L. Purcia, Angelo B. Velarde

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The study attempts to analyze and evaluate Gloc-9’s “Sirena” through Queer Critical Reading approach, which underscores that there exists sexual orientation fluidity within the LGBTQ+ spectrum. With this, the researchers found out that there is a need to oppugn stereotypes within and outside the spectrum, and there exist intrinsic and extrinsic struggles of people in the spectrum as deduced in the literary piece through identifying the characters’ sexual identities shaped and formed as exemplified in the literary piece, determining the prejudices that exist about the main character's sexuality, and distinctively demystifying the social forces or constructs that identify sexual identity.

Keywords: literature, LGBTQ+, spectrum, sexual orientation, queer critical reading

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Authors: Ahmadali Tahmasebimoradi, Chetra Mang, Xavier Lorang

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Thanks to the additive manufacturing process, lattice structures are replacing the traditional structures in aeronautical and automobile industries. In order to evaluate the mechanical response of the lattice structures, one has to resort to numerical techniques. Ansys is a globally well-known and trusted commercial software that allows us to model the lattice structures and analyze their mechanical responses using either solid or beam elements. In this software, a script may be used to systematically generate the lattice structures for any size. On the one hand, solid elements allow us to correctly model the contact between the substrates (the supports of the lattice structure) and the lattice structure, the local plasticity, and the junctions of the microbeams. However, their computational cost increases rapidly with the size of the lattice structure. On the other hand, although beam elements reduce the computational cost drastically, it doesn’t correctly model the contact between the lattice structures and the substrates nor the junctions of the microbeams. Also, the notion of local plasticity is not valid anymore. Moreover, the deformed shape of the lattice structure doesn’t correspond to the deformed shape of the lattice structure using 3D solid elements. In this work, motivated by the pros and cons of the 3D and beam models, a numerically hybrid model is presented for the lattice structures to reduce the computational cost of the simulations while avoiding the aforementioned drawbacks of the beam elements. This approach consists of the utilization of solid elements for the junctions and beam elements for the microbeams connecting the corresponding junctions to each other. When the global response of the structure is linear, the results from the hybrid models are in good agreement with the ones from the 3D models for body-centered cubic with z-struts (BCCZ) and body-centered cubic without z-struts (BCC) lattice structures. However, the hybrid models have difficulty to converge when the effect of large deformation and local plasticity are considerable in the BCCZ structures. Furthermore, the effect of the junction’s size of the hybrid models on the results is investigated. For BCCZ lattice structures, the results are not affected by the junction’s size. This is also valid for BCC lattice structures as long as the ratio of the junction’s size to the diameter of the microbeams is greater than 2. The hybrid model can take into account the geometric defects. As a demonstration, the point clouds of two lattice structures are parametrized in a platform called LATANA (LATtice ANAlysis) developed by IRT-SystemX. In this process, for each microbeam of the lattice structures, an ellipse is fitted to capture the effect of shape variation and roughness. Each ellipse is represented by three parameters; semi-major axis, semi-minor axis, and angle of rotation. Having the parameters of the ellipses, the lattice structures are constructed in Spaceclaim (ANSYS) using the geometrical hybrid approach. The results show a negligible discrepancy between the hybrid and 3D models, while the computational cost of the hybrid model is lower than the computational cost of the 3D model.

Keywords: additive manufacturing, Ansys, geometric defects, hybrid finite element model, lattice structure

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Authors: Jude Inwumoh, Adam P. R. Taylor, Kosala Gunawardane

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Modular multilevel converters (MMC) exhibit a highly scalable and modular characteristic with good voltage/power expansion, fault tolerance capability, low output harmonic content, good redundancy, and a flexible front-end configuration. Fault detection, location, and isolation, as well as maintaining fault ride-through (FRT), are major challenges to MMC reliability and power supply sustainability. Different papers have been reviewed to seek the best MMC configuration with fault capability. DC faults are the most common fault, while the probability that AC fault occurs in a modular multilevel converter (MCC) is low; though, AC faults consequence are severe. This paper reviews several MMC topologies and modulation techniques in tackling faults. These fault control strategies are compared based on cost, complexity, controllability, and power loss. A meshed network of half-bridge (HB) MMC topology was optimal in rendering fault ride through than any other MMC topologies but only when combined with DC circuit breakers (CBS), AC CBS, and fault current limiters (FCL).

Keywords: MMC-HVDC, DC faults, fault current limiters, control scheme

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Authors: Yi F. Wu, Ai Q. Li, Hao Wang

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Taking a novel type of bridge bearings with the diameter being 100mm as an example, the theoretical analysis, the experimental research as well as the numerical simulation of the bearing were conducted. Since the normal compression-shear machines cannot be applied to the small-size bearing, an improved device to test the properties of the bearing was proposed and fabricated. Besides, the simulation of the bearing was conducted on the basis of the explicit finite element software ANSYS/LS-DYNA, and some parameters of the bearing are modified in the finite element model to effectively reduce the computation cost. Results show that all the research methods are capable of revealing the fundamental properties of the small-size bearings, and a combined use of these methods can better catch both the integral properties and the inner detailed mechanical behaviors of the bearing.

Keywords: ANSYS/LS-DYNA, compression shear, contact analysis, explicit algorithm, small-size

Procedia PDF Downloads 184