Yazar "Awais, Muhammad" seçeneğine göre listele

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    Joint Placement and Device Association of UAV Base Stations in IoT Networks
    (Mdpi, 2019) Ahmed, Ashfaq; Awais, Muhammad; Akram, Tallha; Kulaç, Selman; Alhussein, Musaed; Aurangzeb, Khursheed
    Drone base stations (DBSs) have received significant research interest in recent years. They provide a flexible and cost-effective solution to improve the coverage, connectivity, quality of service (QoS), and energy efficiency of large-area Internet of Things (IoT) networks. However, as DBSs are costly and power-limited devices, they require an efficient scheme for their deployment in practical networks. This work proposes a realistic mathematical model for the joint optimization problem of DBS placement and IoT users' assignment in a massive IoT network scenario. The optimization goal is to maximize the connectivity of IoT users by utilizing the minimum number of DBS, while satisfying practical network constraints. Such an optimization problem is NP-hard, and the optimal solution has a complexity exponential to the number of DBSs and IoT users in the network. Furthermore, this work also proposes a linearization scheme and a low-complexity heuristic to solve the problem in polynomial time. The simulations are performed for a number of network scenarios, and demonstrate that the proposed heuristic is numerically accurate and performs close to the optimal solution.
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    Radiation efficiency and nitrogen fertilizer impacts on sunflower crop in contrasting environments of Punjab, Pakistan
    (Springer Heidelberg, 2018) Nasim, Wajid; Ahmad, Ashfaq; Amin, Asad; Tariq, Muhammad; Awais, Muhammad; Saqib, Muhammad; Ali, Shahzad
    Sunflower (Helianthus annuus L.) is the leading non-conventional oilseed crop in Pakistan. Nitrogen fertilizer can affect plant growth and productivity by changing canopy size which has an effect on the radiation use efficiency (RUE) of the crop. The response of sunflower hybrids in terms of phenology, fraction of intercepted radiation (F-i), and RUE to nitrogenous rates (0, 60, 120, 180, and 240 kg ha(-1)) was studied in three field experiments conducted in three various environments: Multan (arid), Faisalabad (semi-arid), and Gujranwala (sub-humid) during spring seasons 2008 and 2009. The treatments were laid out according to a randomized complete block design with split plot arrangements, keeping the sunflower hybrids in main plots and nitrogen rates in subplots, and replicated three times. The results showed Hysun-38 took a maximum number of days to anthesis (101) as compared to Pioneer-64A93 (100) and Hysun-33 (99). The mean values of F-i were 0.850, 0.903, and 0.978, and the estimated values of RUE for total aboveground dry matter were 2.14, 2.47, and 2.65 g MJ(-1) at experimental locations of Multan, Faisalabad, and Gujranwala, respectively. The values of RUE for grain yield (RUEGY) were 0.78, 0.98, and 1.26 g MJ(-1) at experimental locations of Multan, Faisalabad, and Gujranwala, respectively. The average RUEGY values over three locations were 2.61, 2.60, 2.43, and 2.36 g MJ(-2) in N-4 (180 kg ha(-1)), N-5 (240 kg ha(-1)), N-3 (120 kg ha(-1)), and N-2 (60 kg ha-1) treatments, respectively. Increasing rates of N increased RUEGY over the standard treatment N-3 (120 kg N ha(-1)); however, the averaged values over three locations were 1.22, 1.08, 0.99, and 0.92 g MJ(-2) in N-4, N-5, N-3, and N-2 treatments, respectively. Therefore, optimum water and N doses are important for attaining higher RUE, which may enhance sunflower growth and yield.