149 research outputs found
Novel centroid selection approaches for KMeans-clustering based recommender systems
No full textRecommender systems have the ability to filter unseen information for predicting whether a particular user would prefer a given item when making a choice. Over the years, this process has been dependent on robust applications of data mining and machine learning techniques, which are known to have scalability issues when being applied for recommender systems. In this paper, we propose a k-means clustering-based recommendation algorithm, which addresses the scalability issues associated with traditional recommender systems. An issue with traditional k-means clustering algorithms is that they choose the initial k centroid randomly, which leads to inaccurate recommendations and increased cost for offline training of clusters. The work in this paper highlights how centroid selection in k-means based recommender systems can improve performance as well as being cost saving. The proposed centroid selection method has the ability to exploit underlying data correlation structures, which has been proven to exhibit superior accuracy and performance in comparison to the traditional centroid selection strategies, which choose centroids randomly. The proposed approach has been validated with an extensive set of experiments based on five different datasets (from movies, books, and music domain). These experiments prove that the proposed approach provides a better quality cluster and converges quicker than existing approaches, which in turn improves accuracy of the recommendation provided
Correction to: Understanding the process of meanings, materials, and competencies in adoption of mobile banking
No full textCorrection to: Electronic Markets (2022) 32: pp.2445-2469: https://doi.org/10.1007/s12525-022-00610-7. The original article was published on 28 November 2022. In the original article the affiliation of authors Wilson Ozuem, Kerry Howell and Silvia Ranfagni are missing. Given here are the complete affiliations.
Muhammad Naeem: School of Business & Management, Arden University, Arden House, Coventry, CV3 4FJ, UK.
Wilson Ozuem: Institute of Business, Leadership and Industry, University of Cumbria, Lancaster, LA1 1QD, UK.
Kerry Howell: Northumbria University, Newcastle, NE1 8ST, UK.
Silvia Ranfagni: Department of Economics and Business, University of Florence, Via delle Pandette, 9, Florence, 50127, Italy.
Corresponding author: Correspondence to Muhammad Naeem
Calicnemia fortis Dow, Zia, Naeem & Rafi, 2014, sp. nov.
No full textCalicnemia fortis sp. nov. (Figs. 1 – 7) Type material. Holotype: ♂ (ODO/ZYG/ 217), Pakistan, Azad Jammu and Kashmir, Muzaffarabad, Noseri, 11 v 2005, leg. S. A. Zia, deposited in the National Insect Museum, Islamabad, Pakistan. Paratype: ♂ (ODO/ZYG/ 218), data as holotype. Etymology. The species is named fortis, an adjective, meaning robust, referring to the strong build and relatively large size of the species. Description of holotype male. Head: labium dark brown. Labrum black, clypeus black except for 2 small pale, widely separated spots on postclypeus. Mandible bases black. Genae dark brown adjacent to mandible bases, elsewhere dark with irregular pale markings. An indistinct pale area at junction of frons and clypeus, frons otherwise matte black, vertex and occiput same, antennae with scape and pedicel black with brown sections at top, flagellum missing. Ocelli yellowish. Thorax (Fig. 1): Prothorax matte black with grey pruinesence covering most of propleuron, anterior lobe of pronotum and lateral anterior part of middle lobe. Synthorax matte black except for a narrow irregular yellowish stripe on metepisternum, broadest near legs where extending slightly onto mesepimeron, running above and over spiracle, tapering toward but not reaching antealar carina. A broad, irregular yellow stripe occupies much of metepimeron. Legs with coxae pale with obscure dark areas anteriorly and laterally, otherwise mostly dark brown and black with sparse grey pruinosity on trochanters and femora. Wings (Figs. 2 – 3) with 5 postquadrangular cells in Fw, 4 in Hw. 18 Px in Fw, 16 (left) and 15 (right) Px in Hw. Pt pale, covering ca 2 underlying cells, approximately rhombic, but with costal side a little shorter than anal side. Abdomen: S 1 black dorsally, laterally mostly yellow. S 2 mostly black with obscure rusty red markings in apical two thirds. S 3 – 6 red, darkening with each successive segment, black behind posterior carina dorsally and in upper part laterally. S 7 dark red dorsally except at apical extremity, same colour lower laterally, with a poorly defined black stripe between, except in basal ca one-fifth. S 8 black with obscure dark red markings lower laterally and in basal half dorsally. S 9 black except for apical red lower lateral mark. S 10 black. Genital ligula (Fig. 4) typical for group 2 Calicnemia, terminal segment with two broad apical lobes, almost square at ends. Anal appendages of typical form for the genus, as shown in Figs. 5–7 with interior ventral tooth located basally on cercus, bifurcated terminally. Measurements (mm): Abdomen without anal appendages 37, paraprocts ca 1.5; Hw 28.5. Female. Unknown. Variation in paratype male. The paratype male (Fig. 8) does not differ from the holotype in any significant way except that two full length pruinose antehumeral stripes are present, and there is more extensive pruinosity on the prothorax and laterally on the synthorax. Additionally abdominal S 1 – 2 are largely pruinose grey. Measurements (mm): Abdomen without anal appendages 35; Hw 28.5; 18 Px in Fw, 14 (right) or 16 (left) Px in Hw. Diagnosis. A robust group 2 Calicnemia with synthorax black with yellow lateral marks and abdomen with S 2 – 7 wholly or partly red. Separated from all other species of group 2 of Calicnemia except C. hasik Wilson & Reels, 2003, C. mortoni (Laidlaw, 1917), C. nipalica Kimmins, 1958, C. pulverulans (Selys, 1886) and C. rectangulata Laidlaw, 1932 by the black mesepisternum lacking antehumeral markings or with only pruinose blue antehumeral markings. Distinguished from C. pulverulans by the entirely black abdomen and the more rounded ends of the lobes of the terminal segment of the ligula of that species. Distinguished from C. hasik by more extensive red colouration on the abdomen, broader lobes of the terminal segment of the ligula and shorter tooth on the cercus in lateral view. C. rectangulata differs in the extent of the red markings in the abdomen and in having a much larger tooth on the cercus, very prominent in lateral view. C. nipalica has the terminal segment of the ligula deeply divided. C. mortoni has a longer but less broad tooth on the cercus and the terminal segment of the ligula deeply divided. Remarks. In his PhD thesis (Zia 2010) the second author gave this species a name, Indocnemis ahmedi, and presented a (composite) description, but also issued a disclaimer, citing article 8.2 of the International code of Zoological Nomenclature (ICZN 2012), to the effect that “description of new species i.e. Indocnemis ahmedi provided in this dissertation is not issued for public and permanent scientific record or for purposes of zoological nomenclature”. The name ahmedi is therefore not available; in any case it would not have been available because no holotype was designated (article 16.4.1). Calicnemis fortis was found flying within tall grassy vegetation around an open spring which runs into a fast flowing stream. Calicnemia eximia was common at the same site. Unfortunately following the devastating earthquake in October 2005 the spring at the type locality dried up, and the species has not been relocated in that area despite repeated searches by the second author in the following three years. However, Zia (2010) lists two additional males from a location in North West Frontier Province of Pakistan. These specimens have not been seen by the first author and in the view of the second author might represent a different species, because they differ quite substantially in colouration and some other characters as well; therefore they are left out of consideration here. The species should be searched for not just in neighbouring regions of Pakistan, but also in the neighbouring Indian state of Jammu and Kashmir. In life the markings on the abdomen were pinkish red, becoming darker on S 6–7; in the holotype they have faded considerably with preservation. The colour of the paratype male (Fig. 8) is better preserved than that of the holotype, as is the extensive pruinosity on the thorax and abdominal S 1–2. In the holotype there is no indication of any antehumeral markings, but pruinose antehumeral stripes are present in the paratype. Possibly, as is the case in males of some other Calicnemia species, e.g. C. soccifera Yu & Chen, 2013, yellow antehumeral markings are present in immature individuals but later these markings become completely pruinose (Yu & Chen 2013). In the case of C. fortis, possibly the underlying marking fades completely, leading to the condition now seen in the holotype. Calicnemia fortis comes closest to C. pulverulans, from which it differs principally in the colour of the abdomen and details of the genital ligula. Calicnemia pulverulans has been recorded as far west as the Nanda Devi Bisophere Reserve in Uttar Pradesh, India (Kumar 1997), but this is more than 600 km from the type locality of C. fortis. Differences from C. pulverulans and other species most closely resembling the available material of C. fortis are given in the diagnosis. Considering the remaining species in group 2 of Calicnemia, C. fortis males are easily separated from those of C. chaseni (Laidlaw in Campion & Laidlaw, 1928), C. miles (Laidlaw, 1917), C. miniata (Selys, 1886), C. chaoi Wilson, 2004, and C. zhuae Zhang & Yang, 2008, which have bright red or orange antehumeral stripes as well as differences in the anal appendages and genital ligula; uniquely in the genus C. chaoi possesses amber wings (Wilson 2004). Of three Chinese species with males possessing yellow or pruinosed antehumeral stripes: C. gulinensis Yu & Bu, 2008, C. porcata Yu & Bu, 2008 and C. soccifera, C. soccifera has the terminal segment of the genital ligula with much narrower lobes and legs with a red or yellow femur contrasting with a black tibia. Calicnemia gulinensis has an orange abdomen and far more extensive pale markings on labrum and clypeus and C. porcata differs in the colouration of the head, details of the tooth on the cercus and in the ligula, which bears a distinctive ridge centrally on the terminal segment, and has the lobes almost square ended. This leaves two species that have not been placed in either of Lieftinck’s groups within Calicnemia; these are dealt with below. The species group to which C. uenoi Asahina, 1997, from Vietnam belongs is unclear because Asahina provided no illustration of the ligula. Asahina (1997: 22) stated that C. uenoi is “One of the typical Calicnemia species...”, but judging from the illustrations it seems atypical in the form of the tooth on the cercus, a narrow median spine rather than the robust tooth, normally with a bifid tip, and typically placed more basally, that is usual in Calicnemia. The type series of C. uenoi was deposited in the National Museum of Nature and Science, Tokyo, Japan, but at the present time it cannot be located (Akihiko Sasamoto and Takuya Kiyoshi, personal communication). However, in the collection of the Naturalis Biodiversity Center (RMNH), Leiden, there is a male labelled as C. uenoi from the area of the type locality, donated from the collection of Matti Hämäläinen and originally collected by Haruki Karube. It is difficult to reconcile the anal appendages of the RMNH specimen with Asahina’s illustrations, and this specimen seems close to C. hasik. When describing C. hasik, Wilson & Reels (2003: 266) commented on Asahina’s description of C. uenoi and, understandably, concluded that their species was distinct; the RMNH specimen suggests that further study of this matter is needed. It is to be hoped that the type series of C. uenoi will become available in the near future. In any case, C. uenoi as illustrated by Asahina is clearly distinguished from C. fortis by the form and position of the tooth on the cercus, and C. hasik and the RMNH specimen differ from C. fortis in the details of the ligula, anal appendages and colouration. Calicnemia sudhaae Mitra, 1994, known from Mizoram in northeast India and which is said (Mitra 2002) to resemble C. pulverulans, does not appear to have been assigned to either species group within Calicnemia. This species is illustrated in Mitra (2002: figs. 54-56) where the ligula appears to have ribbon-like flagellae, an impression confirmed by the text “flagella one pair, long ribbon like with pointed apex” (Mitra 2002: 56). Therefore C. sudhaae belongs to group 1 of Calicnemia and need not be considered further here. The large size and long wing length of this species partly accounts for the high count of postquadrangular cells in C. fortis, a character that Fraser (1933), following Laidlaw (1917), used to separate Calicnemia from Indocnemis Laidlaw, 1917. Recent authors have seldom or never given counts of the postquadrangular cells in their descriptions of Calicnemia species, but the illustration of the Hw of C. chaoi shows 4 postquadrangular cells (Wilson 2004: 429, fig. 21). Lieftinck (1977: 20, 22) stated that C. miniata males from northern India and Nepal examined have 3 – 4 postquadrangular cells and that even the holotype male of C miles has 3 – 3 - 1 / 2 postquadrangular cells. In fact the wing photograph of C. pulverulans in Laidlaw (1917: plate XV, fig. 3), the same publication where Indocnemis was described and where the count of postquadrangular cells was first used to distinguish Calicnemia from Indocnemis, shows almost 4 postquadrangular cells in the left Fw. It is to be hoped that these examples will finally lay to rest the idea that the count of postquadrangular cells is a character of value for distinguishing Calicnemia from related genera. With the addition of C. fortis, Calicnemia consists of 22 named species, unless C. pyrrhosoma Lieftinck, 1984 is recognised; this name persists on some world Odonata checklists although it was established as a junior synonym of C. doonensis Sangal & Tyagi, 1984 by Hämäläinen (1989). Yu & Bu (2008) commented on the extent of variability of markings with age and possibly location in C. sinensis Lieftinck, 1984, and geographical variation in markings may occur in other species, so that caution is needed in separating species based entirely on colour patterns. However, structural differences in ligula and caudal appendages are also often subtle, rendering Calicnemia a difficult genus to work on. As noted by Yu & Chen (2013), some of the Chinese species “seem to be closely related, and more detailed studies are needed to clarify their true relationships”; we can only extend this statement to the whole genus.Published as part of Dow, Rory A., Zia, Ahmed, Naeem, Muhammad & Rafi, Muhammad Ather, 2014, Calicnemia fortis sp. nov. from Pakistan (Odonata: Zygoptera: Platycnemididae), pp. 338-342 in Zootaxa 3869 (3) on pages 338-342, DOI: 10.11646/zootaxa.3869.3.7, http://zenodo.org/record/22935
Influence of toxic leadership on turnover intention: The mediating role of psychological wellbeing and employee engagement
No full textThe purpose of this study is to examine the presence of toxic leadership in banking sector of Pakistan with its influence on various job related outcomes which are psychological wellbeing, employee engagement and turnover intention of employees. Through random sampling technique six conventional private and public banks were selected based on quantitative approach. In total, 393 participants completed a self-completion structured questionnaire based on voluntary participation. Structural Equation Modelling (SEM) technique was employed by using SmartPLS version 3.0. Results supported the presence of toxic leadership in banking sector of Pakistan due to which turnover intention increases. Toxic leaders also seemed to have significant negative influence on psychological wellbeing and employee engagement. Furthermore, the relationship among toxic leadership and employee's turnover intention is partially intervened by psychological wellbeing and employee engagement. Understanding leaders'/supervisors' behavior is essential for banks which assist them in retaining employees by creating an environment that boost their wellbeing and make them engaged in their work. The HR managers should focus on considering employees' feedback regarding their supervisors in the form of survey or one on one interviews which will help in identifying supervisors with toxic traits. This study contributes to the existing literature by studying an understudied emerging concept of toxic leadership and its various consequences in the banking sector of Pakistan. This study is the first to consider toxic leaders as an antecedent of turnover intention in banking sector in Pakistani context
Influence of Toxic Leadership on Turnover Intention: The Mediating Role of Psychological Wellbeing and Employee Engagement
No full textThe purpose of this study is to examine the presence of toxic leadership in banking sector of Pakistan with its influence on various job related outcomes which are psychological wellbeing, employee engagement and turnover intention of employees. Through random sampling technique six conventional private and public banks were selected based on quantitative approach. In total, 393 participants completed a self-completion structured questionnaire based on voluntary participation. Structural Equation Modelling (SEM) technique was employed by using SmartPLS version 3.0. Results supported the presence of toxic leadership in banking sector of Pakistan due to which turnover intention increases. Toxic leaders also seemed to have significant negative influence on psychological wellbeing and employee engagement. Furthermore, the relationship among toxic leadership and employee’s turnover intention is partially intervened by psychological wellbeing and employee engagement. Understanding leaders’/supervisors’ behavior is essential for banks which assist them in retaining employees by creating an environment that boost their wellbeing and make them engaged in their work. The HR managers should focus on considering employees’ feedback regarding their supervisors in the form of survey or one on one interviews which will help in identifying supervisors with toxic traits. This study contributes to the existing literature by studying an understudied emerging concept of toxic leadership and its various consequences in the banking sector of Pakistan. This study is the first to consider toxic leaders as an antecedent of turnover intention in banking sector in Pakistani context
RETRACTED ARTICLE: In vitro and in vivo biocompatibility study of polyacrylate TiO2@Ag coated nanoparticles for the radiation dose enhancement
No full textWe, the Editors and Publisher of the journal Artificial Cells, Nanomedicine, and Biotechnology, have retracted the following article:Ateeque Ur Rehman, Muhammad Hassan, Sadia Bano, Khizir Farooq, Aun Raza & Muhammad Naeem Anjum (2021) In vitro and in vivo biocompatibility study of polyacrylate TiO2@Ag coated nanoparticles for the radiation dose enhancement. Artificial Cells, Nanomedicine, and Biotechnology, 49(1), 185–193, DOI: 10.1080/21691401.2021.1889574Since publication, concerns were raised about the methods and some images in this article. Specifically, some images in Figure 7 have been duplicated and rotated. When approached for an explanation, the authors were unable to provide a satisfactory explanation for this. The corresponding author has been informed of our decision to retract.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”
An experimental investigation into the stress-dependent mechanical behavior of cohesive soil with application to wellbore instability
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 397-406).This thesis investigates the mechanical behavior of cohesive soils with reference to the applications of wellbore instabilities through an extensive program of laboratory element and model borehole tests. The laboratory tests use Resedimented Boston Blue Clay (RBBC) as an analog test material. Undrained triaxial shear tests have been performed on specimens that were K0-consolidated to stress levels ranging from 0.15 to 10.0 MPa in both compression and extension shear modes. Compression tests were also performed on overconsolidated specimens. Model borehole tests make use of two new automated, high pressure Thick-Walled Cylinder (TWC) devices to study the effects of the following parameters on the borehole response: mode of loading, specimen geometry, preshear lateral stress ratio, drainage conditions, consolidation stress level, stress history, and cavity volumetric strain rate. This testing program has been performed using small and large TWC devices with outer diameter, Do=7.6cm and 15.2cm, respectively. Both devices allow for independent control of the vertical stress and the radial pressures acting on the inner and outer walls of the cylinder, as well as pore pressure. The triaxial compression and extension test results demonstrate remarkable reductions in the undrained strength ratio (su/[sigma]'vc) with consolidation stress level, notable reduction in the stiffness ratio (Eu/[sigma]'vc), increase in the strain to mobilize the peak resistance (ef), and a significant decrease in the large strain friction angle (f'). The model borehole data indicate that most of the reduction in cavity pressure occurs at volume strains less than 5% before the borehole becomes unstable.(cont.) Increases in outer diameter and strain rate lead to a reduction in the minimum borehole pressure. The initial cavity stiffness ratio decreases as consolidation stress level increases. Drained tests have larger cavity strain at a given cavity pressure and lower minimum pressure than the undrained tests. The borehole closure curves were analyzed using a framework originally developed for interpreting undrained shear properties in model pressuremeter tests (Silvestri, 1998). Backfigured undrained strength ratios from these analyses range from su/[sigma]'vc=0.19-0.21 corresponding to an average between the measured triaxial compression and extension strength ratios. The relationship between su/[sigma]'vc and overconsolidation ratio is consistent with element tests.by Naeem Omar Abdulhadi.Ph.D
LT-Set: A Surrogate Model-Based Decision Tool for Low-Temperature District Heating Refurbishment
No full textThe Netherlands aims to reduce greenhouse gas emissions by 49% before 2030, with the built environment contributing 15% of these emissions largely due to the heavy reliance on natural gas to meet space heating demands. To phase out natural gas, alternatives such as heat pumps and district heat networks are being considered. However, adapting existing buildings to lower supply temperature district heating requires effective refurbishment to maintain thermal comfort for occupants. The challenges hindering this process include i) addressing multiple housing typologies at the neighbourhood scale, ii) complexity of evaluating refurbishment measures by decision-makers, iii) uncertainty due to lack of consideration of life cycle costs and occupancy behaviour pre and post-refurbishment leading to performance gaps in energy savings and iv) current computationally demanding and inaccessible tools to assess refurbishment measures. Therefore, this thesis proposes a method to develop a surrogate model-based decision-making tool that can help homeowners efficiently assess optimal, combined refurbishment measures to help homeowners transition to low-temperature district heating. In order to develop this tool, the study examines literature studies that help define the input parameters for the underlying parametric simulation including. This also helped define the key performance indicators including energy savings, hours too cold and global cost. Furthermore, the underlying simulation model with 13 input parameters provides the synthetic training data with 2000 design samples using the uniform Latin hypercube sampling method for each of the three housing archetypes including i) terraced, ii) detached and iii) Portiek apartments. The best-performing model in this instance included artificial neural networks with an R-squared above 0.95. The surrogate model is then integrated into the optimization workflow that forms the framework for an interface decision-making tool that users can use to generate optimal low-temperature ready refurbishment packages. The common low-temperature ready refurbishment packages include maximum airtightness, type C2 CO2 control ventilation system, cavity wall insulation, triple glazing, and internal roof insulation. Furthermore, it can be concluded that its more financially feasible to maintain existing radiators when transitioning to low-temperature heating instead of replacing the radiators with higher capacity. This is because the initial investment in other refurbishment measures not only improves comfort but also delivers significant energy savings that help reduce global costs in the long term.Architecture, Urbanism and Building Sciences | Building Technolog
Assessment of morphological and biochemical characteristics of common purslane (Portulaca oleracea L.) accessions
No full textCommon purslane (Portulaca oleracea L.), is both a wild plant and a weed, and is also recognized for its edible and nutritional value. This study determined morphological and biochemical characteristics of 25 accessions of common purslane. Seeds of the accessions were collected from various locations in Turkiye. The experiment was done four times; two repeats of it were used for recording morphological data while the other two were used for biochemical analysis. Results showed that the accessions BT-Altinkulak, Assem, and Yerli were respectively recorded for the highest plant height, root fresh weight, and plant fresh weight. The highest moisture content (95.14 %) and leaf fresh weight (39.18 g) were exhibited in the Yerli accession. Root length for all the accessions ranged from 18.2 to 30 cm. For biochemical characterization, the highest total phenolic content was found in accession Yagmur (685.4 mg AEE 100-1) while the highest total flavonoid content was found in Assya (0.569 mg mL-1). Anthocyanin was found the highest in Agr Tohum (1.09 mu g mL-1). Cookies were prepared from a mix of common purslane accessions with three different leaf powder quantities i.e., 10 g, 20 g, and 30 g. In product development, cookies with 10 g common purslane powder were found to be the best for all sensory characteristics. Results showed that common purslane accessions are a rich source of various bioactive compounds and have highly diverse morphological and biochemical traits. This diversity among common purslane accessions will assist plant breeding programs in future for the domestication of this wild plant.TUBITAKThis study was a part of the Ph.D. thesis work of 1st author Muhammad Yasir Naeem, and he also acknowledge the TUBITAK for providing scholarship during the Ph.D. (for living expenses) under the program of Bibed 2215
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