Search results for: sampling strategy

Authors: Stephen E. Cross, Donald P. McConnell

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In the past decade, market pressures and decreasing U.S. federal budgets for science and technology have led to a fundamental change in expectations for corporate investments in innovation. The trend to significant, sustained corporate research collaboration with major academic centres has called for rethinking the balance between academic and corporate roles in these relationships. The Georgia Institute of Technology has developed a system-focused strategy for transformational research focused on grand challenges in areas of importance both to faculty and to industry collaborators. A model of an innovation ecosystem is used to guide both research and university-industry collaboration. The paper describes the strategy, the model, and the results to date including the benefits both to university research and industry collaboration. Key lessons learned are presented based on this experience.

Keywords: ecosystem, industry collaboration, innovation, research strategy

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Authors: Der Chyan Lin

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Since the early introduction by Ormondroyd and Den Hartog, vibration absorber (VA) has become one of the most commonly used vibration mitigation strategies. The strategy is most effective for a primary plant subjected to a single frequency excitation. For continuous systems, notable advances in vibration absorption in the multi-frequency system were made. However, the efficacy of the VA strategy for systems under multi-frequency excitation is not well understood. For example, for an N degrees-of-freedom (DOF) primary-absorber system, there are N 'peak' frequencies of large amplitude vibration per every new excitation frequency. In general, the usable range for vibration absorption can be greatly reduced as a result. Frequency modulated harmonic excitation is a commonly seen multi-frequency excitation example: f(t) = cos(ϖ(t)t) where ϖ(t)=ω(1+α sin⁡(δt)). It is known that f(t) has a series expansion given by the Bessel function of the first kind, which implies an infinity of forcing frequencies in the frequency modulated harmonic excitation. For an SDOF system of natural frequency ωₙ subjected to f(t), it can be shown that amplitude peaks emerge at ω₍ₚ,ₖ₎=(ωₙ ± 2kδ)/(α ∓ 1),k∈Z; i.e., there is an infinity of resonant frequencies ω₍ₚ,ₖ₎, k∈Z, making the use of VA strategy ineffective. In this work, we propose an absorber frequency placement strategy for SDOF vibration systems subjected to frequency-modulated excitation. An SDOF linear mass-spring system coupled to lateral absorber systems is used to demonstrate the ideas. Although the mechanical components are linear, the governing equations for the coupled system are nonlinear. We show using N identical absorbers, for N ≫ 1, that (a) there is a cluster of N+1 natural frequencies around every natural absorber frequency, and (b) the absorber frequencies can be moved away from the plant's resonance frequency (ω₀) as N increases. Moreover, we also show the bandwidth of the VA performance increases with N. The derivations of the clustering and bandwidth widening effect will be given, and the superiority of the proposed strategy will be demonstrated via numerical experiments.

Keywords: Bessel function, bandwidth, frequency modulated excitation, vibration absorber

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Authors: Umme Habiba Jasmine, Mzikazi Nduna

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Due to the dearth of exploratory research in Bangladesh on parenting practices and transmission thereof, there is a lack of information on culture-sensitive methodology in studying this topic. This paper aims to share some methodological reflections from the research field, which will address this knowledge gap. Eleven dyads of biological mothers and maternal grandmothers of school-going children constituted the sample, and a female fieldworker conducted one-to-one, semi-structured, in-depth interviews with them. The participants were recruited through purposive sampling through a representative of a cooperative society in Mirpur area in Bangladesh. Four dyads of the sample outside that eleven dyads were discarded because of the unavailability of the other participant of the dyads or unsuitability for an in-depth interview. The sample recruitment strategy of approaching mothers without their known reference body had to be discarded because of existing social insecurity in Dhaka city. To meet the cultural demand of the research field the researcher had to change in the research plan and comply with the cultural tradition of mutual entertainment with food while conducting interviews which helped in engaging in positive interaction. Also, the researcher had to compromise the strict confidentiality to a collectivistic sense of confidentiality of the in-depth interview sessions. This study suggests future researchers to investigate Bangladeshi traditional practices and accommodate the applicable ones in their research plan for qualitative studies, especially the Bengali tradition of hospitality and shared confidentiality for building rapport and for proper access to the targeted information and research participants. Sample recruitment should always accompany a well-accepted reference person in the targeted research field.

Keywords: confidentiality, culture-sensitive, ethics, parenting practices, sampling

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Authors: Ying Han, Weirong Chen, Qi Li

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An energy management method based on equivalent hydrogen consumption minimum strategy is proposed in this paper aiming at the direct-current (DC) microgrid consisting of photovoltaic cells, fuel cells, energy storage devices, converters and DC loads. The rational allocation of fuel cells and battery devices is achieved by adopting equivalent minimum hydrogen consumption strategy with the full use of power generated by photovoltaic cells. Considering the balance of the battery’s state of charge (SOC), the optimal power of the battery under different SOC conditions is obtained and the reference output power of the fuel cell is calculated. And then a droop control method based on time-varying droop coefficient is proposed to realize the automatic charge and discharge control of the battery, balance the system power and maintain the bus voltage. The proposed control strategy is verified by RT-LAB hardware-in-the-loop simulation platform. The simulation results show that the designed control algorithm can realize the rational allocation of DC micro-grid energy and improve the stability of system.

Keywords: DC microgrid, equivalent minimum hydrogen consumption strategy, energy management, time-varying droop coefficient, droop control

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Authors: Aminul Haque, Quazi Zahangir Hossain, Dilshad Sharmin Chowdhury

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The human migration is getting growing concern around the world, and recurrent disasters and climate change impact have great influence on migration. Bangladesh is one of the disaster prone countries that/and has greater susceptibility to stress migration by recurrent disasters and climate change. The study was conducted to investigate the factors that have a strong influence on current migration and changing pattern of life and livelihood means of the southwest coastal part of Bangladesh. Moreover, the study also revealed a strong relationship between disasters and migration and appropriate policy concern. To explore this relation, both qualitative and quantitative methods were applied to a questionnaire survey at household level and simple random sampling technique used in the sampling process along with different secondary data sources for understanding policy concern and practices. The study explores the most influential driver of migration and its relationship with social, economic and environmental drivers. The study denotes that, the environmental driver has a greater effect on the intention of permanent migration (t=1.481, p-value=0.000) at the 1 percent significance level. The significant number of respondents denotes that abrupt pattern of cyclone, flood, salinity intrusion and rainfall are the most significant environmental driver to make a decision on permanent migration. The study also found that the temporary migration pattern has 2-fold increased compared to last ten (10) years. It also appears from the study that environmental factors have a great implication on the changing pattern of the occupation of the study area and it has reported that about 76% of the respondent now in the changing modality of livelihood compare to their traditional practices. The study bares that the migration has foremost impact on children and women by increasing hardship and creating critical social security. The exposure-route of permanent migration is not smooth indeed, these migrations creating urban and conflict in Chittagong hill tracks of Bangladesh. The study denotes that there is not any safeguard of the stress migrant on existing policy and not have any measures for safe migration and resettlement rather considering the emergency response and shelter. The majority of (98%) people believes that migration is not to be the adoption strategies, but contrary to this young group of respondent believes that safe migration could be the adaptation strategy which could bring a positive result compare to the other resilience strategies. On the other hand, the significant number of respondents uttered that appropriate policy measure could be an adaptation strategy for being the formation of a resilient community and reduce the migration by meaningful livelihood options with appropriate protection measure.

Keywords: environmental driver, livelihood, migration, resilience

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Authors: Jo-Ann Müller

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The integration-responsiveness (IR) framework presents four distinct internationalization strategies which differ depending on the extent of pressure the company faces for local responsiveness and global integration. This study applies the framework to standards by examining differences in the relative importance of three types of standards depending on the role the subsidiary plays within the corporate group. Hypotheses are tested empirically in a two-stage procedure. First, the subsidiaries are grouped performing cluster analysis. In the second step, the relationship between cluster affiliation and subsidiary strategy is tested using multinomial Probit estimation. While the level of local responsiveness of a firm relates to the relative importance of national and international formal standards, the degree of vertical integration is associated with the application of internal company.

Keywords: FDI, firm-level data, standards, subsidiary strategy

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Authors: Sidali Khedidji, Noureddine Yassaa, Riad Ladji

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In this study, n-alkanes which are hazardous for the environment and human health were investigated in Sour El Ghozlane suburban atmosphere at a sampling point from April 2013 to Mai 2013. Ambient concentration measurements of n-Alkanes were carried out at a regional study of the cement industry in Sour El Ghozlane. During sampling, the airborne particulate matter was enriched onto PTFE filters by using a two medium volume samplers with or without a size-selective inlet for PM10 and TSP were used and each sampling period lasted approximately 24 h. The organic compounds were characterized using gas chromatography coupled with mass spectrometric detection (GC-MS). Total concentrations for n-Alkanes recorded in Sour El Ghozlane suburban ranged from 42 to 69 ng m-3. Gravimeter method was applied to the black smoke concentration data for Springer seasons. The 24 h average concentrations of n-alkanes contain the PM10 and TSP of Sour El Ghozlane suburban atmosphere were found in the range 0.50–7.06 ng/m3 and 0.29–6.97 ng/m3, respectively, in the sampling period. Meteorological factors, such as (relative humidity and temperature) were typically found to be affecting PMs, especially PM10. Air temperature did not seem to be significantly affecting TSP and PM10 mass concentrations. The guide value fixed by the European Community, 40 μg/m3 was not to exceed 35 days, was exceeded in some samples. However, it should be noted that the value limit fixed by the Algerian regulations 80 μg/m3 has been exceeded in 1 sampler during the period study.

Keywords: n-alkanes, PM10, TSP, particulate matter, cement industry

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Authors: Mejri Achref

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This paper proposes an energy management strategy for an electrical hybrid vehicle which is composed of a Proton Exchange Membrane (PEM) fuel cell and a supercapacitor storage device. In this paper, the mathematical model for the proposed power train, comprising the PEM Fuel Cell, supercapacitor, boost converter, inverter, and vehicular structure, was modeled in MATLAB/Simulink. The proposed algorithm is evaluated for the Highway Fuel Economy Test (HWFET) driving cycle. The obtained results demonstrate the effectiveness of the proposed energy management strategy in reduction of hydrogen consumption.

Keywords: proton exchange membrane fuel cell, hybrid vehicle, hydrogen consumption, energy management strategy

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Authors: Elhadj Bounadja, Mohand Oulhadj Mahmoudi, Abdelkader Djahbar, Zinelaabidine Boudjema

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In this paper we present a novel fuzzy second-order sliding mode control (FSOSMC) for wind energy conversion system based on a doubly-fed induction generator (DFIG). The proposed control strategy combines a fuzzy logic and a second-order sliding mode for the DFIG control. This strategy presents attractive features such as chattering-free, compared to the conventional first and second order sliding mode techniques. The use of this method provides very satisfactory performance for the DFIG control. The overall strategy has been validated on a 1.5-MW wind turbine driven a DFIG using the Matlab/Simulink.

Keywords: doubly fed induction generator, fuzzy second-order sliding mode controller, wind energy

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Authors: Kanokrat Makkwao, Tassanee Prueksasit

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This study aimed to investigate PM₁₀ emitted from different limestone mines in Saraburi province, Thailand. The blasting and crushing were the main processes selected for PM₁₀ sampling. PM₁₀ was collected in two mines including, a limestone mine for cement manufacturing (mine A) and a limestone mine for construction (mine B). The IMPACT samplers were used to collect PM₁₀. At blasting, the points aligning with the upwind and downwind direction were assigned for the sampling. The ranges of PM₁₀ concentrations at mine A and B were 0.267-5.592 and 0.130-0.325 mg/m³, respectively, and the concentration at blasting from mine A was significantly higher than mine B (p < 0.05). During crushing at mine A, the PM₁₀ concentration with the range of 1.153-3.716 and 0.085-1.724 mg/m³ at crusher and piles in respectively were observed whereas the PM₁₀ concentration measured at four sampling points in mine B, including secondary crusher, tertiary crusher, screening point, and piles, were ranged 1.032-16.529, 10.957-74.057, 0.655-4.956, and 0.169-1.699 mg/m³, respectively. The emission of PM₁₀ concentration at the crushing units was different in the ranges depending on types of machine, its operation, dust collection and control system, and environmental conditions.

Keywords: PM₁₀ concentration, limestone mines, blasting, crushing

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Authors: Daodu Joshua Rotimi

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This study investigated the Efficacy of Self-Assessment Metacognitive Strategy on Academic performance in Energy Concepts among Upper Basic Science Students in Ankpa, Kogi State, Nigeria. The research design adopted for the study was a Quasi-experimental control group design which employed a pretest, posttest of the experimental and control groups. The population of the study consisted of one hundred and twenty-four (124) JSSII Students; sixty-five (65) for the experimental group and (59) for the control group. The instrument used for the study was the Energy Concept Performance Test (ECPT), with a reliability coefficient of 0.80. Two research questions were answered using descriptive statistics of mean and standard deviation, while two hypotheses were tested using a t-test at P≤0.05 level of significance. The findings of the study revealed that the use of the Self-Assessment Metacognitive Strategy has a positive effect on students’ performance in energy concepts among upper Basic Science Students leading to high academic performance; also, there is no significant difference in the mean Academic Performance scores between Male and Female students taught Energy Concept using Self-Assessment Metacognitive Strategy. Based on the research findings, recommendations were made, which include that Secondary school teachers should be encouraged the use Self-Assessment Metacognitive strategy so as to make the learning process attractive, interactive and enriching to the learners.

Keywords: metacognition, self-assessment, performance, efficacy

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Authors: Hadi O. Tohme

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This study is a review on the effectiveness of new physiotherapy techniques with external sensory stimulus compared to standard physiotherapy in the daily activities of patients with Parkinson's disease. Twenty studies from 1996 to 2015 were analyzed and discussed in this review, using the rehabilitation strategy with external sensory stimulus evaluating walking, freezing episodes, balance, transfers, and daily activities of parkinsonian patients. The study highlights the effectiveness of the variety of rehabilitation with cueing strategy used in the treatment of Parkinson's disease. Based on the literature review completed, there is a need for more specific trials with better treatment strategies to support the most appropriate choice of physiotherapy intervention using external sensory stimulus to the type and frequency of this stimulus. In addition, no trials examined the long-term benefits of the physiotherapy intervention with the external sensory stimulus. In order to determine if, or how long the improvements due to the external sensory stimulus physiotherapy intervention can last, long-term follow-up should be performed.

Keywords: cueing strategy, external sensory stimulus, parkinson disease, rehabilitation for parkinson, sensory attention focused exercises, sensory strategy reeducation

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Authors: Ali Hajiesmaeili, Mehdi Rahimi, Ehsan Jaberi, Amir Abbas Hosseini

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The purpose of this study is investigating the influences of logistics performance on organizational performance including both marketing & financial aspects, and showing the financial impacts of selecting the right marketing and logistics priorities in line with their supply chain type, and also giving the practitioners an advance identification of their priorities and participation types of supply chain, and the best combination of their strategies and resources in this regard. We made use of the original model’s questionnaire to gather all expert’s data and also SPSS and AMOS Ver.22 to analyze the gathered data. CFA method was also used to test whether a relationship between observed variables and their underlying latent constructs exists. Supply chain strategy implementation leads to logistics performance improvement, and marketing performance will be affected as well. Logistics service providers should focus on enhancement of supply chain performance, since logistics performance has been considered as a basis of evaluation of supply chain management strategy. Consequently, performance of the organization will be enhanced. This case is the first research made in Iran that analyzes the relationship between Logistics & Organizational performance in Home Appliances and Home Entertainment companies.

Keywords: logistics, organizational, performance, supply chain, strategy

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Authors: Inga Milevica

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This study addresses the discourse of scientific articles from 1991 to 2020 on audiovisual translation and translation strategies and tactics in collections of scientific articles (Latvia). Audiovisual translation studies, which are far beyond the paradigm of fiction studies, occupy, if not a marginal, then very far from the central position, nevertheless create their own specific image, for example, in speeches or in scientific articles. It is this created image that is perhaps one of the reasons for the small number of studies of audiovisual translation. The study shows that scientific articles about translation strategy may also contain signs of both zombie science and ‘weekend articles’ (the concept is introduced in the article for the first time); for example, if the names in the original and translation are compared using the strategy classification translation, which is not justified, but is easy to use and allows certain digital calculations to be made. In addition, they often implement the ‘law of conservation of complexity’, for example, replacing the word technique with a formally more ‘complex’ one–strategy. The purpose of the study was to use expert opinion (Yves Gambier) to determine the presence or absence of zombie science and/or weekend article features in selected scientific articles on audiovisual translation and/or translation strategy. The method of semantic, lexical-semantic and contextual analysis was also applied to the selected articles in order to determine the signs of zombie science and/or ‘weekend articles’ – the statement of purpose, the relevance of the study, methods and classifications of translation strategies used. As a result of the study, it turned out that the reviewed articles have certain indicators of zombie science and/or weekend articles, as eloquently evidenced by the comments of the expert, who pointed to the desire to choose the ‘easiest’ classification of translation strategy and especially to the lack of contribution to the scientific field. Accordingly, in scientific articles, characteristic features of the ‘law of conservation of complexity’ appear (replacing the concept of technique with strategy) and the characteristic use of the lexeme problem.

Keywords: scientific article, zombie science, translation strategies, audiovisual translation

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Authors: Yakin Ekin, Onur Akbulut

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This study aims not only to create a summarized background for the effective and efficient use of the potential of Izmir by providing the strategic planning works and institutional and sectoral strategy documents with different purposes realized by all relevant institutions and organizations in Izmir and Aegean Region to steer towards the same priorities and aims, but also focuses on a criticism and comparison viewpoint about tourism sector in Izmir.

Keywords: regional plan, Izmir, tourism, sectoral strategy

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Authors: Matheus Madureira Matos, Alexandre Rodrigues Farias

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Magnetic Resonance Imaging (MRI) is a vital imaging technique used in both clinical and pre-clinical areas to obtain detailed anatomical and functional information. However, MRI scans can be expensive, time-consuming, and often require the use of anesthetics to keep animals still during the imaging process. Anesthetics are commonly administered to animals undergoing MRI scans to ensure they remain still during the imaging process. However, prolonged or repeated exposure to anesthetics can have adverse effects on animals, including physiological alterations and potential toxicity. Minimizing the duration and frequency of anesthesia is, therefore, crucial for the well-being of research animals. In recent years, various sampling trajectories have been investigated to reduce the number of MRI measurements leading to shorter scanning time and minimizing the duration of animal exposure to the effects of anesthetics. Compressed sensing (CS) and sampling trajectories, such as cartesian, spiral, and radial, have emerged as powerful tools to reduce MRI data while preserving diagnostic quality. This work aims to apply CS and cartesian, spiral, and radial sampling trajectories for the reconstruction of MRI of the abdomen of mice sub-sampled at levels below that defined by the Nyquist theorem. The methodology of this work consists of using a fully sampled reference MRI of a female model C57B1/6 mouse acquired experimentally in a 4.7 Tesla MRI scanner for small animals using Spin Echo pulse sequences. The image is down-sampled by cartesian, radial, and spiral sampling paths and then reconstructed by CS. The quality of the reconstructed images is objectively assessed by three quality assessment techniques RMSE (Root mean square error), PSNR (Peak to Signal Noise Ratio), and SSIM (Structural similarity index measure). The utilization of optimized sampling trajectories and CS technique has demonstrated the potential for a significant reduction of up to 70% of image data acquisition. This result translates into shorter scan times, minimizing the duration and frequency of anesthesia administration and reducing the potential risks associated with it.

Keywords: compressed sensing, magnetic resonance, sampling trajectories, small animals

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Authors: Bouchra Abdelilah, Akram El Korchi, Atmane Baddou

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With the very competitive business era that we witness nowadays, companies needs more that anytime to use all the resources they have in order to maximize performance and satisfy the customers’ needs. The changes occurring in the market business are often due to the variations of demand, which requires a very specific supply chain strategy. Supply chains aims to balance cost, quality, and service level and lead time. Still, managers are confused when faced with the strategies working the best for the supply chain: lean, agile and leagile. This paper presents a decision making tool that aims to assist the manager in choosing the supply chain strategy that suits the most his business, depending on the type of product and the nature of demand. Analyzing the different characteristics of supply chain will enable us to guide the manager to the suitable strategy between lean, agile and leagile.

Keywords: supply chain, lean, agile, flexibility, performance

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Authors: Noor Hasmini Abdghani, Nik Kamariah Nikmat, Nor Hayati Ahmad

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Rapid growth of the internet technology led to changes in the consumer lifestyles. This involved customer buying behaviour-based internet that create new kind of buying strategy. Hence, it has summoned many of world firms including Malaysia to generate new quality strategy in preparation to face new customer buying lifestyles. Particularly, this study focused on identifying online customer segment of automobile passenger car customers. Secondly, the objective is to understand online customer’s receptiveness towards internet technologies. This study distributed 700 questionnaires whereby 582 were returned representing 83% response rate. The data were analysed using factor and regression analyses. The result from the factor analysis precipitates four online passenger car segmentations in Malaysia, which are: Segment (1)- Automobile Online shopping Preferences, Segment (2)- Automobile Online Brand Comparison, Segment (3)- Automobile Online Information Seeking and Segment (4)- Automobile Offline Shopping Preferences. In understanding the online customer’s receptiveness towards internet, the regression result shows that there is significant relationship between each of four segments of online passenger car customer with attitude towards automobile online shopping. This implies that, for online customers to have receptiveness toward internet technologies, he or she must have preferences toward online shopping or at least prefer to browse any related information online even if the actual purchase is made at the traditional store. With this proposed segmentation strategy, the firms especially the automobile firms will be able to understand their online customer behavior. At least, the proposed segmentation strategy will help the firms to strategize quality management approach for their online customers’ buying decision making.

Keywords: Automobile, Market Segmentation, Online Shopping Attitude, Quality Management Strategy

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Authors: Indrasen Raghupatruni, Michael Glora, Ralf Diekmann, Thomas Demmer

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As the trend in automotive technology is fast moving towards hybridization and electrification to curb emissions as well as to improve the fuel efficiency, air-conditioning systems in passenger cars have not caught up with this trend and still remain as the major energy consumers amongst others. Adsorption based air-conditioning systems, e.g. with silica-gel water pair, which are already in use for residential and commercial applications, are now being considered as a technology leap once proven feasible for the passenger cars. In this paper we discuss a methodology, challenges and feasibility of implementing an adsorption based air-conditioning system in a passenger car utilizing the exhaust waste heat. We also propose an optimized control strategy with interfaces to the engine control unit of the vehicle for operating this system with reasonable efficiency supported by our simulation and validation results in a prototype vehicle, additionally comparing to existing implementations, simulation based as well as experimental. Finally we discuss the influence of start-stop and hybrid systems on the operation strategy of the adsorption air-conditioning system.

Keywords: adsorption air-conditioning, feasibility study, optimized control strategy, prototype vehicle

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Authors: Péter Tanos, József Kovács, Angéla Anda, Gábor Várbíró, Sándor Molnár, István Gábor Hatvani

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The River Tisza is the second largest river in Central Europe. In this study, Morlet wavelet spectrum (periodicity) analysis was used with chemical, biological and physical water quality data for the Hungarian section of the River Tisza. In the research 15, water quality parameters measured at 14 sampling sites in the River Tisza and 4 sampling sites in the main artificial changes were assessed for the time period 1993 - 2005. Results show that annual periodicity was not always to be found in the water quality parameters, at least at certain sampling sites. Periodicity was found to vary over space and time, but in general, an increase was observed in the company of higher trophic states of the river heading downstream.

Keywords: annual periodicity water quality, spatiotemporal variability of periodic behavior, Morlet wavelet spectrum analysis, River Tisza

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Authors: Sidali Khedidji, Riad Ladji, Noureddine Yassaa

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In this study, particulate matter (PM10) which are hazardous for environment and human health were investigated in Sour El Ghozlane suburban atmosphere at a sampling point from March 2013 to April 2013. Ambient concentration measurements of polycyclic aromatic hydrocarbons were carried out at a regional study of the cement industry in Sour El Ghozlane. During sampling, the airborne particulate matter was enriched onto PTFE filters by using a two medium volume samplers with or without a size-selective inlet for PM10 and TSP were used and each sampling period lasted approximately 24 h. The organic compounds were characterized using gas chromatography coupled with mass spectrometric detection (GC-MSD). Total concentrations for PAHs recorded in sour el ghozlane suburban ranged from 101 to 204 ng m-3. Gravimeter method was applied to the black smoke concentration data for Springer seasons. The 24 h average concentrations of PM10 and TSP of Sour El Ghozlane suburban atmosphere were found in the range 4.76–165.76 μg/m3 and 28.63–800.14 μg/m3, respectively, in the sampling period. Meteorological factors, such as (relative humidity and temperature) were typically found to be affecting PMs, especially PM10. Air temperature did not seem to be significantly affecting TSP and PM10 mass concentrations.The guide value fixed by the European Community «40 μg/m3» not to exceed 35 days, were exceeded in some samples. However, it should be noted that the value limit fixed by the Algerian regulations «80 μg/m3» has been exceeded in 3 samplers during the period study.

Keywords: PAHs, PM10, TSP, particulate matter, cement industry

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Authors: Yuri Boiko, Ci Lin, Iluju Kiringa, Tet Yeap

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The performance of a BLDC motor controlled by the Kalman filter-based position-sensorless drive is studied in terms of its dependence on the system’s parameters' variations. The effects of system’s parameters changes on the dynamic behavior of state variables are verified. Simulated is a closed-loop control scheme with a Kalman filter in the feedback line. Distinguished are two separate data sampling modes in analyzing feedback output from the BLDC motor: (1) equal angular separation and (2) equal time intervals. In case (1), the data are collected via equal intervals Δθ of rotor’s angular position θᵢ, i.e., keeping Δθ=const. In case (2), the data collection time points tᵢ are separated by equal sampling time intervals Δt=const. Demonstrated are the effects of the parameters changes on the sensorless control flow, in particular, reduction of the torque ripples, switching spikes, torque load balancing. It is specifically shown that an efficient suppression of commutation induced torque ripples is achievable selection of the sampling rate in the Kalman filter settings above certain critical value. The computational cost of such suppression is shown to be higher for the motors with lower induction values of the windings.

Keywords: BLDC motor, Kalman filter, sensorless drive, state variables, torque ripples reduction, sampling rate

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Authors: Doaa Saad, Igor Verner, Rinat B. Rosenberg-Kima

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This case study demonstrates how the Task-Centered Instructional Strategy can be used to develop robotics competencies in middle-school science teachers without programming knowledge, thereby reducing their anxiety about robotics. Sixteen middle school science teachers participated in a teachers’ professional development program. The strategy combines the progression of real-world tasks with explicit instruction that serves as the backbone of instruction. The designed progression includes three tasks that integrate building and programming robots, pedagogy, and science knowledge, with an increasing level of complexity and decreasing level of support. We used EV3 LEGO kits and programming blocks, a new technology for most of the participating teachers. Pre-post questionnaires were used to examine teachers’ anxiety in performing robotics tasks before the program began and after the program ended. In addition, post-program questionnaires were used to obtain teachers’ feedback on the program’s overall quality. The case study results showed that teachers were less anxious about performing robotics tasks after the program and were highly satisfied with the professional development program. Overall, our research findings indicate a positive effect of the Task-Centered Instructional Strategy for preparing in-service science teachers to integrate robotics activities into their science classes.

Keywords: competencies, educational robotics, task-centered instructional strategy, teachers’ professional development

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Authors: Marie Pavelková, Hana Lukášová

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Pupils´ inquisitiveness at the beginning of their school attendance is reflected by characteristics of the questions they ask. Clearly most of the classroom communication sequences are initiated by the teacher. But the teaching process also includes questions initiated by pupils in the need to satisfy their need for knowledge. The purpose of our research is to present the results of our pre-research strategy of occurrence of pupil-initiated questions in math lessons at the lower elementary school level, and to reveal the extent to which they are influenced by the teacher´s teaching strategy. We used the research methods of direct and indirect observations of fifth year classes in primary school. We focused on questions asked by the pupils in their math lessons. Our research sample for the pre-research observation method was a collection of video recordings available online. We used them for analysing the nature of pupils´ questions identified there. On the basis of the analysis, we hereby present the results concerning the nature of pupils´ questions asked in math lessons on the lower elementary school level. The interpretation of the collected results will be the starting point for the selection of research strategies in the next research stages concerning pupils’ questions in the future.

Keywords: beginning of schooling, pre-research, questions of pupils, teaching strategy

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Authors: Ehab AbdulRazzaq Hussein

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Quantum cryptography (QC) is an emerging technology for secure key distribution with single-photon transmissions. In contrast to classical cryptographic schemes, the security of QC schemes is guaranteed by the fundamental laws of nature. Their security stems from the impossibility to distinguish non-orthogonal quantum states with certainty. A potential eavesdropper introduces errors in the transmissions, which can later be discovered by the legitimate participants of the communication. In this paper, the modeling approach is proposed for QC protocol BB84 using polarization coding. The single-photon system is assumed to be used in the designed models. Thus, Eve cannot use beam-splitting strategy to eavesdrop on the quantum channel transmission. The only eavesdropping strategy possible to Eve is the intercept/resend strategy. After quantum transmission of the QC protocol, the quantum bit error rate (QBER) is estimated and compared with a threshold value. If it is above this value the procedure must be stopped and performed later again.

Keywords: security, key distribution, cryptography, quantum protocols, Quantum Cryptography (QC), Quantum Key Distribution (QKD).

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Authors: Soheib Fergani

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This paper concerns with the formal asymptotic stability guarantees, analysis and evaluation of a nonlinear controlled unmanned aerial vehicles (uav) for trajectory tracking purpose. As the system has been recognised as an under-actuated non linear system, the control strategy has been oriented towards a hierarchical control. The dynamics of the system and the mission purpose make it mandatory to provide an absolute proof of the vehicle stability during the maneuvers. For this sake, this work establishes the complete theoretical proof for an implementable control oriented strategy that asymptotically stabilizes (GAS and LISS) the system and has never been provided in previous works. The considered model is reorganized into two partly decoupled sub-systems. The concidered control strategy is presented into two stages: the first sub-system is controlled by a nonlinear backstepping controller that generates the desired control inputs to stabilize the second sub-system. This methodology is then applied to a harware in the loop uav simulator (SiMoDrones) that reproduces the realistic behaviour of the uav in an indoor environment has been performed to show the efficiency of the proposed strategy.

Keywords: UAV application, trajectory tracking, backstepping, sliding mode control, input to state stability, stability evaluation

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Authors: M. Mourad, K. Mahmoud

Abstract:

Recently hybrid vehicles have become a major concern as one alternative vehicles. This type of hybrid vehicle contributes greatly to reducing pollution. Therefore, this work studies the influence of electrification phase of hybrid electric vehicle on emission of vehicle at different road conditions. To accomplish this investigation, a simulation model was used to evaluate the external characteristics of the hybrid electric vehicle according to variant conditions of road resistances. Therefore, this paper reports a methodology to decrease the vehicle emission especially greenhouse gas emission inside cities. The results show the effect of electrification on vehicle performance characteristics. The results show that CO₂ emission of vehicle decreases up to 50.6% according to an urban driving cycle due to applying the electrification strategy for hybrid electric vehicle.

Keywords: electrification strategy, hybrid electric vehicle, driving cycle, CO2 emission

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Authors: Omar Amoudi, Mariya Khalid

Abstract:

The limitation of the public funds for the infrastructure projects and with the deterioration of international oil prices and the negative consequences on the economies of oil producing and exporting countries, Oman has encouraged the partnership between the public and private sectors. As the private sector has a role in planning, financing, designing, operating and the maintenance of the public services. There is no doubt that, the adoption of Public Private Partnership (PPP) strategy faces many challenges which might affect the project seriously if it is not overcome in earlier time. These challenges depend on the level of understanding of the strategy, the roles and regulations and the availability of resources as well. This research aims at identifying the challenges facing the PPP infrastructure projects in Oman based on the similar previous studies supported by questionnaire survey and semi structured interviews. It also seeks to discuss the rationale for adoption in Oman and uncover the current status of PPP strategy. The identified challenges were ranked according to the importance index of each challenge. After analysis of data, it has observed that, the main challenges facing PPPs projects in Oman are high participation cost, high projects cost and regulation changes. The PPP strategy has to be adopted well and with a high level of experience in order to ensure a successful implementation of PPP projects in Oman.

Keywords: public private partnership (PPP), challenges, infrastructure, Oman

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Authors: Deborah O. Ajumobi, Michael Kyobe

Abstract:

Studies show that women entrepreneurs are constrained and faced with challenges that inhibit the growth and performance of their businesses. However, with their human competencies, mobile technology and the appropriate business strategy, women-led SMEs can steer their businesses to better performance. While the need for SMEs to align these three elements has been suggested, there is limited knowledge on how SMEs can achieve this and no studies to the authors’ knowledge have examined this in women-led SMEs. This study therefore seeks to fill this gap by investigating how Women-led SMEs can best align these three elements to enhance business performance. In light of this, extensive literature review and theoretical work on the phenomenon has been conducted. Given the existence of the interplay between these three elements, we argue that the perspective of alignment as gestalts is most appropriate in determining the best way women-Led SMEs may align these aspects.

Keywords: women-led SMEs, human Competencies, mobile technology, business strategy, alignment

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Authors: Feng-Tsung Cheng, Shu-Li Wang, Mei-Fang Wu, , Hui-Yu Chuang

Abstract:

Due to the rapid development of modern technology, the widespread usage of the Internet makes business environment changing quickly. In order to be a leader in the global competitive market and to pursuit survive, “changing” becomes an unspoken rules need to follow for the company survival. The purpose of this paper is to build change model by using SWOT, strategy map, and balance scorecard, KPI and change management theory. The research findings indicate that organizational change plan formulated by the case company should require the employee to resist change factors and performance management system issues into consideration and must be set organizational change related programs, such as performance appraisal reward system, consulting and counseling mechanisms programs to improve motivation and reduce staff negative emotions. Then according to the model revised strategy maps and performance indicators proposed in this paper, such as strategy maps add and modify corporate culture, improve internal processes management, increase the growth rate of net income and other strategies. The performance indicators are based on strategy maps new and modified by adding net income growth rate, to achieve target production rate, manpower training achievement rates and other indicators, through amendments to achieve the company’s goal, be a leading brand of precision machinery industry.

Keywords: organizational change, SWOT analysis, strategy maps, performance indicators

Procedia PDF Downloads 255