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Mapping evolution of dynamic web ontologies
Khattak, A.M.,Pervez, Z.,Khan, W.A.,Khan, A.M.,Latif, K.,Lee, S.Y. Elsevier science 2015 Information sciences Vol.303 No.-
Information on the web and web services that are revised by stakeholders is growing incredibly. The presentation of this information has shifted from a representational model of web information with loosely clustered terminology to semi-formal terminology and even to formal ontology. Mediation (i.e., mapping) is required for systems and services to share information. Mappings are established between ontologies in order to resolve terminological and conceptual incompatibilities. Due to new discoveries in the field of information sharing, the body of knowledge has become more structured and refined. The domain ontologies that represent bodies of knowledge need to be able to accommodate new information. This allows for the ontology to evolve from one consistent state to another. Changes in resources cause existing mappings between ontologies to be unreliable and stale. This highlights the need for mapping evolution (regeneration) as it would eliminate the discrepancies from the existing mappings. In order to re-establish the mappings between dynamic ontologies, the existing systems require a complete mapping process to be restructured, and this process is time consuming. This paper proposes a mapping reconciliation approach between the updated ontologies that has been found to take less time to process compared to the time of existing systems when only the changed resources are considered and also eliminates the staleness of the existing mappings. The proposed approach employs the change history of ontology in order to store the ontology change information, which helps to drastically reduce the reconciliation time of the mappings between dynamic ontologies. A comprehensive evaluation of the performance of the proposed system on standard data sets has been conducted. The experimental results of the proposed system in comparison with six existing mapping systems are provided in this paper using 13 different data sets, which support our claims.
Khattak, W.A.,Khan, T.,Ha, J.H.,Ul-Islam, M.,Kang, M.K.,Park, J.K. IPC Science and Technology Press ; Elsevier Scienc 2013 Enzyme and microbial technology Vol.53 No.5
Malt hydrolyzing enzymes and yeast glycolytic and fermentation enzymes in the waste from beer fermentation broth (WBFB) were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A new 'one-pot consecutive batch strategy' was developed for efficient bio-ethanol production by simultaneous saccharification and fermentation (SSF) using WBFB without additional enzymes, microbial cells, or carbohydrates. Bio-ethanol production was conducted in batches using WBFB supernatant in the first phase at 25-67<SUP>o</SUP>C and 50rpm, followed by the addition of 3% WBFB solid residue to the existing culture broth in the second phase at 67<SUP>o</SUP>C. The ethanol production increased from 50 to 102.5g/L when bare supernatant was used in the first phase, and then to 219g ethanol/L in the second phase. The amount of ethanol obtained using this strategy was almost equal to that obtained using the original WBFB containing 25% solid residue at 33<SUP>o</SUP>C, and more than double that obtained when bare supernatant was used. Microscopic and gel electrophoresis studies revealed yeast cell wall degradation and secretion of cellular material into the surrounding medium. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) supported the existence of enzymes in WBFB involved in bioethanol production at elevated temperatures. The results of this study will provide insight for the development of new strategies for biofuel production.
이중대역 오프셋 카세그레인 반사판 안테나용 메타재질구조 모사 주파수 선택표면 부반사판 설계
김현수,강승택,M.K.Khattak,전진수,박정훈 한국위성정보통신학회 2015 한국위성정보통신학회논문지 Vol.10 No.2
본 논문에서는, 오프셋 카세그레인 반사판 안테나가 물리적 크기의 증가없이 Ku와 Ka 이중대역 신호를 다룰 수 있는 구조로 설계된 다. 계산시간 및 구현비용을 고려하여, 주반사판 대신에 부반사판에 Ka대역 신호는 반사시키고 Ku대역은 통과시키는 주파수 선택성 을 부여한다. 쌍곡선 부반사판 표면의 주파수 선택표면은 8각형 금속 링을 위 아래로 둔 다층매질의 단위 쎌의 주기적 형태로 구성된 다. 정밀한 전자기 모의시험을 통해 제안한 구조가 19 GHz와 45 GHz에서 동작함을 확인한다. In this paper, a design of an offset Cassegrain antenna is proposed for Ku and Ka dual-band without increasing the antenna size. For Efficiency of computation and implementation, the frequency selectivity surface (FSS) of reflecting the Ka-band signal and passing the Ku-band is provided for the sub-reflector instead of the main reflector. The proposed FSS hyperboloid sub-reflector is the periodic structure of a unit cell comprising octagon metal rings embedded in the multiple layers. The proposed design is verified for 19 GHz and 45 GHz bands by the use of precise electromagneitc-field simulations.
Current advancements of magnetic nanoparticles in adsorption and degradation of organic pollutants
Ul-Islam, M.,Ullah, M. W.,Khan, S.,Manan, S.,Khattak, W. A.,Ahmad, W.,Shah, N.,Park, J. K. Springer Science + Business Media 2017 Environmental Science and Pollution Research Vol.24 No.14
<P>Nanotechnology is a fast-emerging field and has received applications in almost every field of life. Exploration of new synthetic technologies for size and shape control of nanomaterials is getting immense consideration owing to their exceptional properties and applications. Magnetic nanoparticles (MNPs) are among the most important group of nanoparticles thanks to their diverse applications in medical, electronic, environmental, and industrial sectors. There have been numerous synthetic routes of MNPs including thermal decomposition, co-precipitation, microemulsion, microwave assisted, chemical vapor deposition, combustion synthesis, and laser pyrolysis synthesis. The synthesized MNPs have been successfully applied in medical fields for therapy, bioimaging, drug delivery, and so on. Among environmental aspects, there has been great intimidation of organic pollutants in air and water. Utilization of various wastes as adsorbents has removed 80 to 99.9% of pollutants from contaminated water. MNPs as adsorbents compared to coarse-grained counterparts have seven times higher capacity in removing water pollutants and degrading organic contaminants. This study is focused to introduce and compile various routes of MNP synthesis together with their significant role in water purifications and degradation of organic compounds. The review has compiled recent investigation, and we hope it will find the interest of researchers dealing with nanoparticles and environmental research.</P>
Antimicrobial and Biocompatible Properties of Nanomaterials
Ul-Islam, M.,Shehzad, A.,Khan, S.,Khattak, W.A.,Ullah, M.W.,Park, J.K. American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.1
The rapid development of drug-resistant characteristics in pathogenic viral, bacterial, and fungal species and the consequent spread of infectious diseases are currently receiving serious attention. Indeed, there is a pressing demand to explore novel materials and develop new strategies that can address these issues of serious concern. Nanomaterials are currently proving to be the most capable therapeutic agents to cope with such hazards. The exceptional physiochemical properties and impressive antimicrobial capabilities of nanoparticles have provoked their utilization in biomedical fields. Nanomaterials of both organic and inorganic nature have shown the capabilities of disrupting microbial cells through different mechanisms. Along with the direct influence on the microbial cell membrane, DNA and proteins, these nanomaterials produce reactive oxygen species (ROS) that damage cell components and viruses. Currently, a serious hazard associated with these antimicrobial nanomaterials is their toxicity to human and animal cells. Extensive studies have reported the dose, time, and cell-dependent toxicology of various nanomaterials, and some have shown excellent biocompatible properties. Nevertheless, there is still debate regarding the use of nanomaterials for medical applications. Therefore, in this review, the antimicrobial activities of various nanomaterials with details of their acting mechanisms were compiled. The relative toxic and biocompatible behavior of nanomaterials emphasized in this study provides information pertaining to their practical applicability in medical fields.
Katubi Khadijah Mohammedsaleh,Warsi Al-Zoha,Aziz Fatima,Khattak Zafar A.K.,Warsi Muhammad Farooq,Al-Buriahi M.S.,Alrowaili Z. A.,Yousaf Sheraz 한국물리학회 2023 Current Applied Physics Vol.51 No.-
This study focuses on the production of hydrogen through electrocatalysis using a newly synthesized and characterized nano-hybrid composite based electrocatalyst. The electrocatalyst is composed of mixed metal oxides and reduced graphene oxide. The electrocatalysts were evaluated for their structural and morphological characteristics through the implementation of diverse characterization methodologies. The utilization of electrochemical methodologies, including linear sweep voltammetry, Tafel slope, and electrochemical active surface area measurements, provided valuable information regarding the catalytic efficiency and effectiveness of the electrocatalysts for the hydrogen evolution reaction. The findings indicate that the electrocatalyst WO3–CuO/ rGO demonstrated exceptional catalytic efficiency, as evidenced by a current density of 200 mA/cm2 at an overpotential of -400 mV, a Tafel slope of 44 mVdec-1, and low charge transfer resistance. Additionally, the chronoamperometric analysis exhibited the electrocatalyst’s durability, highlighting its potential for practical implementations.