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Purpose: The purpose of this paper is to design an output-feedback algorithm based on low-power observer (LPO), robust chattering-free controller and nonlinear disturbance observer (DO) to achieve trajectory tracking of quadrotor in the Cartesian plane. Design/methodology/approach: To achieve trajectory tracking control, firstly the decoupled rotational and translational model of quadrotor are modified by introducing backstepped state-space variables. In the second step, robust integral sliding mode control is designed based on the proportional-integral-derivative (PID) technique. In the third step, a DO is constructed. In next step, the measurable outputs, i.e. rotational and translational state variables, are used to design the LPO. Finally, in the control algorithm all state variables and its rates are replaced with its estimates obtained using the state-observer. Findings: The finding includes output-feedback control (OFC) algorithm designed by using a LPO. A modified backstepping model for rotational and rotational systems is developed prior to the design of integral sliding mode control based on PID technique. Unlike traditional high-gain observers (HGO), this paper used the LPO for state estimation of quadrotor systems to solve the problem of peaking phenomenon in HGO. Furthermore, a nonlinear DO is designed such that it attenuates disturbance with unknown magnitude and frequency. Moreover, a chattering reduction criterion has been introduced to solve the inherited chattering issue of controllers based on sliding mode technique. Practical implications: This paper presents input and output data-driven model-free control algorithm. That is, only input and output of the quadrotor model are required to achieve the trajectory tracking control. Therefore, for practical implementation, the number of on-board sensor is reduced. Originality/value: Although extensive research has been done for designing OFC algorithms for quadrotor, LPO has never been implemented for the rotational and translational state estimations of quadrotor. Furthermore, the mathematical model of rotational and translational systems is modified by using backstepped variables followed by the controller designed using PID and integral sliding mode control technique. Moreover, a DO is developed for attenuation of disturbance with unknown bound, magnitude and frequency. [ABSTRACT FROM AUTHOR]

From the last decades different types of network schemes are pitched to enhance the user performance. Software Defined Networks (SDN) is also considered as important factor for different network schemes and its proper administration or management. Due to major deployment in today's networking era SDN are further sub divided in to commercial and opensource controllers. Commercial and open-source controllers are utilized in different type of businesses. According to our knowledge considerable amount of literature is available on these controllers but did not provide or analyse performance of these controllers on different network parameters. This paper evaluates and compares the performance of two well-known SDN open-source controllers POX and RYU with two performance assessments. The first assessment is the implementation of optimal path by using Dijkstra's algorithm from source to destination. Second assessment is the creation of a custom topology in our desired tool (MiniNet emulator). Then, the performance in terms of QoS parameters such as Jitter, throughput, packet loss, and packet delivery ratio are computed by two end hosts in each network. After the assessments, the performance of POX are optimal as compare to the RYU and best suited to be deployed in any scenario. [ABSTRACT FROM AUTHOR]

Background: Road traffic injuries (RTIs) are leading cause of unintentional injuries and death across the globe. Road traffic crashes (RTCs) are neglected public health issue specially in low and middle income countries. Aims: The study aims to investigate risk factors of RTCs and assess quality of pre and post hospital care. Methods: A cross sectional study was conducted in Lahore, Pakistan from July 2022 – December 2022. Randomly selected 300 patients were interviewed using structured questionnaire at four purposively selected major tertiary care hospitals of Lahore. Binary logistic regression was used to find association between risk factors and injury severity (P < 0.05). Results: Data analysis showed that age groups 16–30 years (27%), older than 55 years (27%) comprised substantial proportion. A total of 65% RTCs attributed to human errors/factors. Most road crash victims (88% and 87%, respectively) were not wearing helmets and didn’t hold a valid driver's license. According to injury severity score, 75% of victims had severe injury. Odds of severe injury were more among aged more than 55 years and human error attributed RTCs. There was significant gap between perception and expectation of patients receiving healthcare services (P < 0.05). Conclusion: This is first study in Pakistan that examine quality of pre and post hospital care of RCVs. Significant quality gaps were found in pre and post hospital care of RCVs as per Servqual model that need to be addressed. Serious efforts are required to reduce growing burden of RTCs in Pakistan. [ABSTRACT FROM AUTHOR]

Objective: To determine prevalence of depression among university students in Pakistan according to patient health questionnaire. Study Design: Cross-sectional survey. Place and Duration of Study: University of Karachi, from May 2017 till Aug 2017. Methodology: Depression was assessed by using Patient Health Questionnaire. Questionnaire was distributed to 130 students of different departments. Results: Response rate of our study was 72.30%. Males were slightly more (51.10%) than females in our survey. Majority of our survey participants belonged to on-campus (59.60%) courses. Students belonging to Punjabi community were having the highest participation (35.10%) in the survey. Urdu speaking and Pathan students were next in line with higher participation (33% and 21.30% respectively). The number of the students from Anatomy department was in higher proportion (59.60%). A big majority of students belonged to moderate to severe depression categories (54.30%, 13.80% and 10.60% with moderate, moderately severe and severe depression respectively). Females were suffering more from moderate to severe depression (78.20%) than the males. Students younger than 22 years of age were suffering more from depression according to our study (92.50%). Sindhi students were all suffering from severe depression while those of Urdu speaking were in moderate to moderately severe category. Conclusion: Hence it is concluded from our survey that four out of five students are suffering from depression and it was also affected by different demographic variables as well. [ABSTRACT FROM AUTHOR]

Background: Corneal transplantation or keratoplasty has developed rapidly in the past 10 years. Penetrating keratoplasty, a procedure consisting of full-thickness replacement of the cornea, has been the dominant procedure for more than half a century, and successfully caters to most causes of corneal blindness. Objective: To study the perception and knowledge about corneal transplant amongst young generation. Methodology: A cross sectional study was conducted n medical students. Sample of 200 people was collected through non probability convenient based sampling method and a closed ended questionnaire was filled to people. Results: The results showed that majority (75%) of students knew that eyes can be donated after death but only 20% knew that the ideal time of donation was within 6 hours of death. Most of the participants (70%) were willing of donating eyes. Perceived reasons for not pledging eyes by the students as unacceptable idea of separating the eyes from the body (30.9%), lack of awareness (29.8%), objection by family members (28.5%), and religious beliefs (12.7%). Conclusion: It was concluded that most of the students know about eye donation but they do not like to donate the eye because of their own belief, family influence or lack of awareness and needs creation of awareness about eye donation in the community. [ABSTRACT FROM AUTHOR]