Miracle-dz/UniFAR-FTUs huggingface dataset:
Heteroscedastic BART via Multiplicative Regression Trees

Abstract Bayesian additive regression trees (BART) has become increasingly popular as a flexible and scalable nonparametric regression approach for modern applied statistics problems. For the practitioner dealing with large and complex nonlinear response surfaces, its advantages include a matrix-free formulation and the lack of a requirement to prespecify a confining regression basis. Although flexible in fitting the mean, BART has been limited by its reliance on a constant variance error model. Alleviating this limitation, we propose HBART, a nonparametric heteroscedastic elaboration of BART. In BART, the mean function is modeled with a sum of trees, each of which determines an additive contribution to the mean. In HBART, the variance function is further modeled with a product of trees, each of which determines a multiplicative contribution to the variance. Like the mean model, this flexible, multidimensional variance model is entirely nonparametric with no need for the prespecification of a confining basis. Moreover, with this enhancement, HBART can provide insights into the potential relationships of the predictors with both the mean and the variance. Practical implementations of HBART with revealing new diagnostic plots are demonstrated with simulated and real data on used car prices and song year of release. Supplementary materials for this article are available online.
Apply ADD method to the Development Process Life-Cycle Phases within DoDAF

This paper presents an approach to work with the process life-cycle of the U.S. Department of Defense Architecture Framework (DoDAF), and extend existing architecture description process and artifacts within DoDAF that match the scope of the ADD life-cycle phases to enhanced system life-cycle development process that includes process-iteration based development and determination in an integral manner.
Tailoring structure of inclusion with strain-induced closure to reduce Poisson's ratio of composite materials

A novel 3D continuum shell structure is introduced as inclusion for composite materials with special mechanical properties in this paper. Its geometry is based on a hollow re-entrant tetrahedron. In a composite, such an inclusion can demonstrate a closure effect induced by external compression. Its specific deformation mechanism results in a special character of deformation and affects effective (global) mechanical properties of the composite. A finite-element method is used to explore quantitatively and qualitatively the deformation mechanism of the suggested inclusion and its effect on the overall mechanical performance of the composite. In this study, geometrical features of the inclusion are used as parameters. The obtained results demonstrate that this kind of inclusion could reduce the composite's Poisson's ratio; moreover, its magnitude is adjustable by changing geometrical parameters of the inclusion. Besides, an overall hardening effect is achieved for the composite, with the magnitude of global stiffness also significantly affected by geometrical features of the inclusion. Thus, the developed inclusion actually provides a potential to develop new composites with a tunable Poisson's ratio and enhanced mechanical properties.
Estimating the principal components of correlation matrices from all their empirical eigenvectors

We consider the problem of estimating the principal components of a population covariance matrix from a limited number of measurement data. Using a combination of random matrix and information-theoretic tools, we show that all the eigenmodes of the sample correlation matrices are informative, and not only the top ones. We show how this information can be exploited when prior information about the principal component, such as whether it is localized or not, is available by mapping the estimation problem onto the search for the ground state of a spin-glass–like effective Hamiltonian encoding the prior. Results are illustrated numerically on the spiked covariance model.
Editorial: Models, technologies and approaches toward widening the open access to learning and education

This special issue is devoted to novel models and technologies as well as current methodical approaches and best practices in the field of Open Learning and Open Education as enablers of personal growth, social inclusion, open innovation, and sustainable economic development in the challenging conditions of globalization and world-wide competition in productivity and services. The Open Access to Learning and Education embraces not only various technologies, such as mobile and intelligent technologies, content and data management, user-centered design, but also diverse directions of use, such as e-learning and training, organizational development, Massive Open Online Courses, special needs education, all building an excellent basis for various educational and business arrangements that widen the learning and education opportunities for all people around the globe. Against this background, this special issue demonstrates the immense speed and relentlessness of the Open Access concept growth presenting a wide range of examples toward supporting competency and skills development to ensure highly capable human capital, and solve individual, business, urban, demographic, health as well as social inclusion issues in today’s highly demanding digital economy environment. https://doi.org/10.34105/j.kmel. 2016.08. 001
Estimation of Customer Dissatisfaction Based on Service Quality Gaps by Correlation and Regression Analysis in a Travel Agency

The main aim of this paper is to analyze the correlation of service quality gaps and to estimate customer dissatisfaction based on those gaps in the Iran Travel Agency (ITA) as one of the international travel agencies of the country. For this purpose, a questionnaire has been designed based on the SERVQUAL approach (perceptions and expectations), which includes five major categories of service quality dimensions and are subdivided into 15 dimensions and an additional question for measuring the overall dissatisfaction. 30 regular customers of the agency have been asked to fill the questionnaires. The correlation of service quality gaps and then the relationship between overall customer dissatisfaction and major service quality gaps are determined by correlation and regression analysis. The findings imply that the maximum value of gap is related to 'appealing accommodation facilities', which is a part of the dimension of tangibles. The minimum values of the gaps are also related to 'on time delivery' and 'reputation of service. The correlation analysis has not addressed any significant correlation among the gaps. Ultimately, regression analysis has approved and estimated linear correlation between the gaps of empathy and tangibles and the overall customer dissatisfaction.
Developing Credibility Guidelines for e-Government Website Design: An Empirical Study

Information Communication Technologies (ICTs) have changed how private sector business is conducted online. ICTs have also been adopted in the public sector, principally in terms of egovernment. Users’ interaction with e-government can be influenced by a number of issues, notably egovernment website credibility. Therefore, credibility is an important factor in e-government development, but one that has received little attention. This study has evaluated credibility of current egovernment websites. The findings indicate a number of credibility problems, and suggest that current e-government websites need to improve their credibility. As such, this study has developed a set of credibility guidelines, which guide designers to develop credibility in e-government websites. The final goal is to develop more credible e-government that can generate greater users’ participation.
A Review of Solar Energy Collectors: Models and Applications

A current study and discussion in detail about many solar energy collectors of various types, components, classifications and configurations, through the analysis of their performance, is our aim through this review paper. The effects of the geometrical parameters of the solar air collectors as well as the functioning parameters on heat transfer and fluid flow processes were also discussed in detail. The numerical, analytical, and experimental analyses on different models of flat plate solar air collectors with various thermal transfer enhancement strategies were shown in various stages, i.e., modelling, control, measurement, and visualization of airfield, determination of heat transfer, control of friction loss and pressure drop, and evaluation of the thermal performance by the measurement of the augmentation in the temperature of the working fluid at a given solar irradiance and under given flow rate. We concluded this review by identifying the various applications possible for the solar air collectors such as heating and cooling of houses, drying agricultural food materials, and water desalination process.
The Financial Development of the Greek Apparel Industry during the Crisis

The difficult economic situation the country faces and the prolonged economic recession led to further contraction in consumer demand. In this economical reality the average reduction in turnover of clothing industry in many cases exceeds 30%. The competition within the industry will intensify over the next years and as a result the market will retain either large companies with high cash ability of funds and wide sales network, or small and flexible, which target to a specific consumer's market (niche markets). Within this context, many companies of clothing industry proceeded in the closure of their stores in the last year.
Instanton-monopole correspondence from M-branes on $\mathbb S^1$ and little string theory

We study BPS excitations in M5-M2-brane configurations with a compact transverse direction, which are also relevant for type IIa and IIb little string theories. These configurations are dual to a class of toric elliptically fibered Calabi-Yau manifolds $X_N$ with manifest $SL(2, \mathbb{Z}) \times SL(2,\mathbb{Z})$ modular symmetry. They admit two dual gauge theory descriptions. For both, the non-perturbative partition function can be written as an expansion of the topological string partition function of $X_N$ with respect to either of the two modular parameters. We analyze the resulting BPS counting functions in detail and find that they can be fully constructed as linear combinations of the BPS counting functions of M5-M2-brane configurations with non-compact transverse directions. For certain M2-brane configurations, we also find that the free energies in the two dual theories agree with each other, which points to a new correspondence between instanton and monopole configurations. These results are also a manifestation of T-duality between type IIa and IIb little string theories.
Community interactions dampen acidification effects in a coastal plankton system

Changing seawater chemistry towards reduced pH as a result of increasing atmospheric carbon dioxide (CO2) is affecting oceanic organisms, particularly calcifying species. Responses of non-calcifying consumers are highly variable and mainly mediated through indirect ocean acidification effects induced by changing the biochemical content of their prey, as shown within single species and simple 2-trophic level systems. However, it can be expected that indirect CO2 impacts observed at the single species level are compensated at the ecosystem level by species richness and complex trophic interactions. A dampening of CO2-effects can be further expected for coastal communities adapted to strong natural fluctuations in pCO2, typical for productive coastal habitats. Here we show that a plankton community of the Kiel Fjord was tolerant to CO2 partial pressure (pCO2) levels projected for the end of this century (<1400 µatm), and only subtle differences were observed at the extremely high value of 4000 µatm. We found similar phyto- and microzooplankton biomass and copepod abundance and egg production across all CO2 treatment levels. Stoichiometric phytoplankton food quality was minimally different at the highest pCO2 treatment, but was far from being potentially limiting for copepods. These results are in contrast to studies that include only a single species, which observe strong indirect CO2 effects for herbivores and suggest limitations of biological responses at the level of organism to community. Although this coastal plankton community was highly tolerant to high fluctuations in pCO2, increase in hypoxia and CO2 uptake by the ocean can aggravate acidification and may lead to pH changes outside the range presently experienced by coastal organisms.
Spatial variation in otolith chemistry of Epinephelus merra in Baa Atoll, Maldives

The particular geography of Maldives archipelago induces that the economy is essentially dependant on marine resources. Despite the fact that pelagic resources are the most exploited, reef fin fishery strongly increased due to tourism and export industry development in the last decades (Sattar et al., this issue). Although there are no clear signs of overexploitation and decline of fish population overall, Sattar et al. (this issue) have concerns for some groupers species in some locations. Chabanet et al. (this issue) also report no sighting of sharks in Baa for instance. Thus, Maldivian government and stakeholders remain vigilant, and several MPAs were established in various atolls. The goal of the Atoll Ecosystem Conservation Project (http://www.biodiversity.mv/aec/) aims to establish a network of conservation for Baa atoll for instance. Anthropogenic activities have strongly affected coral reef ecosystems worldwide and Marine Protected Areas (MPAs) are increasingly considered as an effective tool for fishery management (Roberts et al., 2001) and biodiversity conservation (Micheli et al., 2004). To design MPAs and soundly manage fish stocks, it is vital to obtain information on connectivity between populations, migration and movement, and describe population dynamics. A variety of methods have been used to assess movements between populations such as population genetic (Bradbury et al., 2008), hydrodynamic and lagrangian dispersal models (Cowen et al., 2000), external tags (Willis et al., 2001, Sattar et al., this issue), acoustic telemetry (Topping et al., 2005) or transgenerational marking of embryonic otolith (Thorrold et al., 2006). Recently, elemental composition of fish otoliths has been successfully used to examine connectivity between populations (Milton and Cheney, 2001; Chittaro et al., 2006). Elemental chemistry is used because trace elements from the environment are incorporated into the otolith during growth and the otolith is metabolically inert (Campana, 1999). According to Hamer et al;(2003), the success of using otolith chemistry to measure connectivity would be dependant on a detectable level of chemical variation at biologically relevant spatial scales. The present study investigated whether otoliths of Epinephelus merra collected from different coral reefs in Baa Atoll could be discriminated on the basis of multielemental chemistry. The study aimed at evaluating the potential of otolith microchemistry technique to study connectivity among reefs at Baa Atoll, and brings on the long run key data for MPAs selection.
Long-term evaluation of air sensor technology under ambient conditions in Denver, Colorado

Air pollution sensors are quickly proliferating for use in a wide variety of applications, with a low price point that supports use in high-density networks, citizen science, and individual consumer use. This emerging technology motivates the assessment under real-world conditions, including varying pollution levels and environmental conditions. A seven-month, systematic field evaluation of low-cost air pollution sensors was performed in Denver, Colorado, over 2015–2016; the location was chosen to evaluate the sensors in a high-altitude, cool, and dry climate. A suite of particulate matter (PM), ozone (O3), and nitrogen dioxide (NO2) sensors were deployed in triplicate and were collocated with federal equivalent method (FEM) monitors at an urban regulatory site. Sensors were evaluated for their data completeness, correlation with reference monitors, and ability to reproduce trends in pollution data, such as daily concentration values and wind-direction patterns. Most sensors showed high data completeness when data loggers were functioning properly. The sensors displayed a range of correlations with reference instruments, from poor to very high (e.g., hourly-average PM Pearson correlations with reference measurements varied from 0.01 to 0.86). Some sensors showed a change in response to laboratory audits/testing from before the sampling campaign to afterwards, such as Aeroqual, where the O3 response slope changed from about 1.2 to 0.6. Some PM sensors measured wind-direction and time-of-day trends similar to those measured by reference monitors, while others did not. This study showed different results for sensor performance than previous studies performed by the U.S. EPA and others, which could be due to different geographic location, meteorology, and aerosol properties. These results imply that continued field testing is necessary to understand emerging air sensing technology.
Customer engagement and response toward an extended-stay hotel: a case study of Grande Centre Point Hotel.

The purpose of this study was to assess the level of engagement and response of extended-stay customers of the Grande Centre Point Hotel Ratchadamri, Bangkok, Thailand. The research instrument consisted of a three-part questionnaire covering customer demography, customer engagement, and customer response. Purposive sampling from customers staying in the hotel longer than 30 days and a self-administered questionnaire were used for data gathering from 138 respondents in March 2012. Data analysis included both descriptive and inferential statistics. The research results showed that most of respondents were male (89.1%), aged between 20 and 49 years (81.2%), with a monthly income of less than USD 10,000 (55.8%), and working for private companies (62.3%). Regarding customer engagement, respondents gave higher scores for functional engagement than emotional engagement. Most of the engagement factors were at the “high” level, except for “hotel location” which was at the “very high” level and for “staff service mind” which was at the “medium” level. For the Customer response category, respondents gave a “high” level for all factors. Based on hypothesis testing at the . 05 significance level, respondents with different gender, age, occupation, and income were significantly different in their engagement levels, while respondents with different age, occupation, and income were significantly different in their response levels.
Second Life for Virtual Communities in Education: Sharing Teaching Principles?

How do expert educators perceive their teaching practice and professional identity in the openness of immersive virtual environments? This paper summarises some findings of a study of teaching practitioners’ narratives from the UK about the use of virtual worlds or MUVEs (Multi-User Virtual Environments) in higher education and adult language learning classes in the UK. The main questions addressed are whether it is possible in environments such as SL to identify socio-constructivist principles of education practice (in general and more specifically with regards to second language teaching) and whether there are grounds for critical teaching and «reflective practice» (Edge, 2011, Guichon, 2009) in virtual worlds used for higher education that have either been specifically designed for teaching or not. Within the theoretical framework of socio-constructivism and critical multimedia literacy, the data will be commented focusing on how the communities of practice are presented and how the process of teaching and learning is perceived. The analysis is qualitative and aims at revealing the positioning of expert practitioners vis-a-vis educational strategies implemented and advantages or disadvantages of using immersive virtual environments to achieve learning goals.
THERMAL RESPONSE OF A NON AIR CONDITIONED BUILDING BY USING INSULATION OF VARIOUS THICKNESSES AT THE DIFFERENT POSITIONS OF THE WALLS AND ROOF AT COLD STATIONS OF INDIA

The performance of a non air-conditioned building has been analyzed for cold climatic regions of India by using various thicknesses of insulation at different positions of the walls and roof i.e. on the external surface and the inner surface of the walls and in the middle of the walls. Single zone isolated building, having dimensions of 4m x 4m x 3m, and with south facing window 2 m x 1.6 m size, has been analyzed in this study. The periodic solution of the heat conduction equation describing the heat transmission through the different building components, floor, walls and roof has been adopted. Ambient temperature and total solar radiation intercepted by the building envelope have been represented through Fourier series. Traditional construction with 220 mm Burnt Clay Brick (BCB) wall, plastered 15 mm on both side without insulation and with insulation at different positions like internal and external surface of walls and in between the walls have been analyzed. It has been observed that thermal comfort for the three stations considered in this study can not be ensured in the month of January if the building is traditional (non- insulated).
ARE DRIVERS OF PSYCHOLOGICAL WELL-BEING SIMILAR TO THE DRIVERS OF ILL-BEING?

Received: 20 April 2017 Final Accepted: 23 May 2017 Published: June 2017 Psychological well being is about lives going well. It is a combination of being good and functioning effectively. However, it does not mean feeling good all the time, the experience of painful emotions like disappointment, failure, grief is a normal part of life and being able to manage these negative emotions is essential for long-term well being. So the need for the study of this topic is to explain that many of the drivers of well being are not the same as the drivers of ill-being. The study is hypothesized that, personality, demographic factors, socioeconomic factors and international activities are responsible for both psychological well-being and ill-being respectively. To study the objectives, secondary tools were used. With study carried out, with the review of Literature, it suggests that personality factors, demographic factors and socio-economic factors are equally responsible for psychological well-being and ill-being respectively but international activities are only responsible for psychological well-being and not for ill-being.
Security and Privacy of Big Data in Mobile Devices

Presently, the volume of data generated via mobile devices is at an exponential rate due to the rapid advancement in internet-enabled mobile devices, which makes it complex to ensure the privacy and security of this data. Cloud-based server is currently considered one of the most reliable solutions to address these issues. Nevertheless, the increasing uncertainties of storing useful and sensitive big data in a public cloud have suppressed the exploration of this option. In our paper, we meticulously reviewed the drawbacks in the current adopted solutions for security and privacy of big data within mobile devices. As the utilization of mobile platforms is increasingly generating large data, the current traditional methods of cryptography will not be able to efficiently ensure the security and privacy of this big data. Therefore, this paper will propose the utilization of Federated Identity Management that is Openstack cloud-based as an effective solution that can ensure the privacy and security of big data within mobile device ecosystem.