Wyniki wyszukiwania - Biblioteka Nauki

1

A new and fast approximation algorithm for vertex cover using a maximum independent set (VCUMI)

100%

Khan I. , Riaz N.

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tom Vol. 25, No. 4

5--18

EN

The importance of non-deterministic polynomial (NP) problems in real world scenarios has compelled researchers to consider simple ways of finding approximate solutions to these problems in polynomial time. Minimum vertex cover is an NP complete problem, where the objective is to cover all the edges in a graph with the minimal number of vertices possible. The maximal independent set and maximal clique problems also belong to the same class. An important property that we have analyzed while considering various approaches to find approximate solutions to the minimum vertex cover problem (MVC) is that solving MVC directly can result in a bigger error ratio. We propose a new approximation algorithm for the minimum vertex cover problem called vertex cover using a maximum independent set (VCUMI). This algorithm works by removing the nodes of a maximum independent set until the graph is an approximate solution of MVC. Based on empirical results, it can be stated that VCUMI outperforms all competing algorithms presented in the literature. Based on all the benchmarks used, VCUMI achieved the worst case error ratio of 1.033, while VSA, MDG and NOVAC-1 gave the worst error ratios of 1.583, 1.107 and 1.04, respectively.

2

Radiotracer investigations of municipal sewage treatment stations

61%

Farooq M. , Khan I. , Ghiyas-ud-Din , Gul S. , Palige J. , Dobrowolski A.

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tom Vol. 48, nr 1

57-61

EN

Tracer techniques, which are well-established methods in process dynamics studies in industry, were applied to investigate the dynamics of sewage treatment process. The concept of residence time distribution (RTD) was used to investigate the efficiency of the primary clarifier, aeration tank and secondary clarifier of a sewage treatment plant. Preliminary treatment and modeling of the tracer data was performed using the software DTS Pro Ver. 4.20. A big short - circuiting (by-passing) with a large volume of stagnant zones were found in the primary and secondary clarifiers, while no stagnant zone was detected in the aeration tank.

3

Linear-nonlinear optical, dielectric and surface microscopic investigation of KH2PO4 crystal to uncover the decisive impact of dopant glycine

61%

Khan I. , Kalainathan S. , Baig M. I. , Shkir M. , Alfaify S. , Ghramh H. A. , Anis M.

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tom Vol. 36, No. 4

662--667

EN

Present investigation has been started to perform the comparative study of pure and glycine doped KH2PO4 (KDP) single crystals grown by most commercial slow solvent evaporation technique. The grown crystals were subjected to single crystal X-ray diffraction analysis to determine their structural parameters. The linear optical studies of pure and glycine doped KDP crystal have been undertaken within 200 nm to 1100 nm wavelength range by means of UV-Vis studies. The enhancement in second harmonic generation (SHG) efficiency of glycine doped KDP crystal has been determined using a standard Kurtz-Perry powder test. The dielectric measurements have been carried out to explore the impact of glycine dopant on dielectric constant and dielectric loss of KDP crystal. The surface growth habitat and etch pit density of glycine doped KDP crystal have been evaluated using the results of microscopic etching studies. In light of obtained results the suitability of glycine doped KDP crystal for device applications has been discussed.

4

Brucellosis in Mirpur, Azad Kashmir Pakistan: a livestock threat for neighboring zones

51%

Mubeen H. , Khan I. , Saleem M. H. , Akhtar R. , Ali S. , Saqib M. , Khan A. U. , Umar S.

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nr 07

EN

The objective of the present study was to determine the prevalence of brucellosis in household animals of Mirpur, Azad Kashmir due to its geographic importance. A total of 360 blood samples of cattle, buffaloes, sheep and goats were initially screened through Rose Bengal Plate test (RBPT) and then positive samples were subjected to Enzyme Linked Immunosorbent Assay (ELISA) for confirmation and quantification of antibody titers. Molecular confirmation of serologically positive samples was performed by real time polymerase chain reaction (PCR). RBPT and ELISA showed a total of 8.6% and 6.87% positive samples respectively. The species wise seropositivity by RBPT was greater in cattle followed by buffaloes, goats and sheep. Similarly ELISA showed more seropositivity in cattle than buffaloes, while sheep and goats were negative for brucellosis by ELISA. RT-PCR revealed 100% samples positive for Brucella abortus by species specific PCR. This study revealed the presence of Brucella abortus in Mirpur for the first time. Since brucellosis is listed in transboundary diseases, its presence in this geographically important region could be a potential threat for neighboring countries.

5

Urban sprawl and its impact on soil and plant species in Peshawar, Pakistan

51%

Ali K. , Shuaib M. , Malik T. , Shah S. S. , Ali S. , Shah N. A. , Hussain F. , Khan I. , Akhtar N. , Li Z.

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nr 4

EN

The current paper aims to highlight: 1) Major problems due to urbanization, including land cutting, erosion, overgrazing, biodiversity loss, and climate change. 2) The impact of grazing on plant community structure and ecosystem functioning. 3) Management and conservation of natural ecosystems in Sheikh Muhammdi Peshawar. For the current work, three different sites (Zones 1, 11, 111) were selected in the local area. The populations of the local area have increased very rapidly in the last 40 to 50 years. Anthropogenic activities associated with population and industrialization in the district, with vegetation clear for developing of towns and roads, has resulted in the substitution of vegetations with the dark color surface, the temperature of the environments much higher than before, leading to the phenomenon of the urban heat island effect. This urbanization and construction work at Amman plots Sheikh Muhammadi Peshawar is causing the extinction of vegetation and there would be no more wild vegetation in the near future in that particular area.

6

Effect of charcoal:dextran stripped fetal bovine serum on in vitro development of bovine embryos

51%

Mesalam A. , Kong R. , Khan I. , Chowdhury M. M. R. , Choi B.-H. , Kim S. W. , Cho K.-W. , Jin J.-I. , Kong I.-K.

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nr 4