Presence Of Queues Research Articles

Performance Evaluation of M|M|1 Queueing Models in Cloud Computing Environments

Queues are ubiquitous, occurring at any given moment. Traffic congestion, healthcare facilities, dining establishments, and even the digital realm. With the continuous advancement of global society, there has been a significant surge in the utilization of the internet, leading to a substantial increase in the volume of incoming service requests occurring on a constant basis. The emergence of cloud computing can be attributed to its inherent advantages in terms of user comfort and cost-effectiveness. The utilization of cloud computing enables users to do computational tasks without the need for physical server ownership. However, it is important to note that the presence of queues is not eliminated as a result. Queueing theory was established as a means to address the issue of lengthy and sluggish lines. This research focuses on the analysis and optimization of queueing systems in order to develop efficient and expedient queues, while also considering cost-effectiveness. In the context of cloud computing, particular attention is given to the goal of energy conservation. This study aims to examine the performance of M|M| queues within the context of cloud computing. It will include both numerical and textual analyses, as well as proofs, while primarily focusing on comparing the similarities and differences of two M|M| queues.

Reasons for low adherence to anticoagulant therapy with warfarin

Objective. To assess patients' adherence to therapy with warfarin, to identify main reasons for its discontinuation or lack of timely the international normalized ratio (INR) monitoring. Material and methods. The database of anticoagulant rooms controlling the intake of warfarin was analyzed. Adherence to warfarin therapy was assessed by interviewing patients. The data were statistically processed using the computational program Statistica v10.0. Results. Only 20.6% of the patients who were prescribed warfarin to prevent thromboembolic events in the presence of non-valvular atrial fibrillation (AF) continue to take it. Of them, 69.2% regularly monitored INR. In the subgroup using warfarin after artificial heart valves had been installed; 32.4% of the patients continued its outpatient use; in 24.5% of them had an INR within the therapeutic range of ≥70%. There were main reasons for the termination of INR control: the fear of visiting polyclinics and anticoagulant rooms due to the epidemiological situation in 2021-2022; the presence of queues in the polyclinics; residence change and the inability to control INR within walking distance; movement difficulties experienced by patients with limited mobility; most patients stopped INR control because they were not properly informed about its necessity and the possible consequences of uncontrolled intake of warfarin. Conclusion. Among the patients with non-valvular AF and prosthetic heart valves who were prescribed warfarin, 74.9% stopped taking it after discharging from the hospital. The patients receiving warfarin in an outpatient setting controlled INR in ≤83.3% of cases.

Residence time in one-dimensional random walks in presence of moving defects

Residence time is relevant in several applicative problems, such as the pedestrian motion in presence of queues and the study of water flows in runoff ponds. In this last context, it is important to control the residence time since it is strictly connected to the pond efficiency in terms of deposition of pollutants. These applications motivated our detailed study of residence time in presence of moving obstacles and defects for a particle performing a one-dimensional random walk. More precisely, for a particle conditioned to exit through the right endpoint, we measure the typical time needed to cross the entire lattice in presence of defects. These are defined as lattice sites with jump probabilities modified adding a bias to the values used at regular sites. We find explicit formulae for the residence time and discuss several models of moving defects. The presence of a stochastic updating rule for the motion of the defect smooths the local residence time profiles found in the case of a static defect.

Research of ethics and deontological aspects in pharmacies

The aim of the study was to study the ethical and deontological aspects related to the professional activities of pharmacists. Materials and methods. To achieve the goal of the study, an analysis of scientific sources on ethical and deontological issues related to the professional activities of pharmacists (pharmacists) was carried. During the research, the methods of information search, systematization, comparison, and generalization, as well as sociological research methods were used. The object of the study was the results of questionnaires and interviews of visitors and employees of pharmacy chains of KP “Prymula”; pharmacy chains that are part of the company “Apteka-Mahnoliia”: Pharmacy ANC, Kopiika and pharmacies of the social project “Blahodiia”; pharmacy chains that are part of the company Med-service. Descriptive statistics methods were used to present the obtained data. To determine the significance of individual factors (Wij), obtained because of the questionnaire are listed to the corresponding specific weight of the component. Results. The systematization of the following factors: which determine the quality of service; related to the purchase of drugs (medicines); which determine the priority of qualities of pharmacies; determining the relationship between a pharmacist and a doctor. It was found that the most negative impact on pharmacy visitors, from the point of view of consumers, was the inattention of the pharmacist, his mistakes, irritability, rudeness, incompetence, as well as the high price of drugs, queues, and slow service. From the point of view of pharmacists, pharmacy visitors were most negatively affected by rudeness, incompetence of pharmacy employees, irritability, the price of drugs, the range of drugs, the presence of queues, and slow service. The results of the assessment of the parameters that determine the relationship between the pharmacist and the doctor showed that, in general, pharmacists maintain the authority of the doctor in the eyes of visitors and, along with the latter, carry out educational work among the population. However, a fifth of respondents assume the functions of a doctor, which is completely unacceptable. Using the technology of sociological survey, the analysis was carried out and, based on ranking, the leading rational and emotional factors that form loyalty for certain segments of the professional activity of pharmacies using ethical and deontological principles were identified. Conclusions. The systematization of the following factors: which determine the quality of service; related to the purchase of drugs that cause dissatisfaction; which determine the dissatisfaction of visitors to pharmacies; which determine the priority of qualities of pharmacies; determining the relationship between pharmacist and doctor. Using the technology of sociological survey, the analysis was carried out and, based on ranking, the leading rational and emotional factors that form loyalty for certain segments of the professional activity of pharmacies using ethical and deontological principles were identified. It is established that the views on consumer dissatisfaction with visiting pharmacies differ insignificantly from the views of pharmacists. Pharmacist visitors are most negatively affected by the inattention and rudeness of the pharmacist, the high price of drugs, the presence of queues and slow service. It is established that, in general, pharmacists maintain the authority of the doctor in the eyes of visitors and, along with the latter, conduct educational work among the population.

Analysis of satisfaction with the accessibility and quality of primary health care for patients with pathology of lower limb arteries

Aim. To study the opinion of the population about satisfaction with the accessibility and quality of primary health care for diseases of the arteries of the lower extremities in institutions of the Sverdlovsk region, as well as to identify problems in the organization of its provision.
 Methods. From January to June 2019, an anonymous survey of 384 patients with diseases of the arteries of the lower extremities who applied for a consultative appointment with a cardiovascular surgeon at the clinic of the Sverdlovsk Regional Clinical Hospital No. 1 was carried out. A representative sample was determined by formulae, in which, out of the general population the number of registered cases of arterial disease of the lower limbs in the Sverdlovsk region, was acceptable. The survey involved 301 (78.4%) men and 83 (21.6%) women.
 Results. More than 90% of respondents were over 50 years old. More than 35% of respondents expected a referral for a consultation with a specialist later than 1 month away. The accessibility and timeliness of obtaining specialized medical care were influenced by the geographical remoteness from the regional center. The presence of queues in outpatient clinics at the place of residence, the difficulty in obtaining a coupon for an appointment with a doctor, the inaccessibility of free research, as well as the inconvenient work schedule of specialist doctors were the main reasons for not obtaining medical care. When examined in the clinic at the place of residence, more than half of the respondents used their own money. Just over a third of patients (35.2%) thought that the level of medical care has improved over the past decade, 19.5% thought that it had become worse, 16.4% that it had not changed, and 28.9% found it difficult to answer. About half of the respondents (48.8%) were satisfied with the result of the medical care provided, 11.2% were not satisfied, and 40% of the patients found it difficult to answer.
 Conclusion. The shortcomings identified in the organization of outpatient care in medical institutions of the Sverdlovsk region indicate the need to improve primary health care for patients with lower limb arterial disease. Such improvements will achieve the goals and objectives of the National Healthcare project through the development of telemedicine technologies and the development of organizational and functional patient routing models, standard operating procedures for examining more patients with cardiovascular pathology by primary care physicians, and their active introduction into public health practice.

Crowdsourcing Phase and Timing of Pre-Timed Traffic Signals in the Presence of Queues: Algorithms and Back-End System Architecture

This paper describes a crowdsourcing-based system for phase and timing estimation of pre-timed traffic signals. The input crowd is a real-time feed of sparse and low-frequency probe vehicle data, and the output is an estimated collection of Signal Phase and Timing (SPaT) information. The estimations could be ultimately fed into a connected vehicle's driver assistant application. Different from the authors' previous work, the approach described in this paper ensures the accuracy of the SPaT estimations even in the presence of queues. This was achieved by investigating the probe data influenced by the heavy traffic and the delay in queues. This paper is also a sequel to the authors' previous work as it provides an in-depth overview of the crowdsourcing algorithms and their back-end implementation. The accuracy of the crowdsourcing algorithm is also experimentally evaluated for a selection of pre-timed traffic lights in San Francisco, CA, USA, by utilizing a real-time data feed of San Francisco's public buses as an example data source.

On service guarantees of fair-queueing schedulers in real systems

In most systems, fair-queueing packet schedulers are the algorithms of choice for providing bandwidth and delay guarantees. These guarantees are computed assuming that the scheduler is directly attached to the transmit unit with no interposed buffering, and, for timestamp-based schedulers, that the exact number of bits transmitted is known when timestamps need to be updated.Unfortunately, both assumptions are unrealistic. In particular, real communication devices normally include FIFO queues (possibly very deep ones) between the scheduler and the transmit unit. And the presence of these queues does invalidate the proofs of the service guarantees of existing timestamp-based fair-queueing schedulers.In this paper we address these issues with the following two contributions. First, we show how to modify timestamp-based, worst-case optimal and quasi-optimal fair-queueing schedulers so as to comply with the presence of FIFO queues, and with uncertainty on the number of bits transmitted. Second, we provide analytical bounds of the actual guarantees provided, in these real-world conditions, both by modified timestamp-based fair-queueing schedulers and by basic round-robin schedulers. These results should help designers to make informed decisions and sound tradeoffs when building systems.

Optimal sharing of surgical costs in the presence of queues

We deal with a cost-allocation problem arising from sharing a medical service in the presence of queues. We use a standard queuing theory model in a context of several medical procedures, a certain demand for treatment and a maximum average waiting-time guaranteed by the government. We show that the sharing of an operating-theatre to treat patients of different medical disciplines leads to a cost reduction. We then compute an optimal fee per procedure for the use of the operating theatre, based on the Shapley value. Afterwards, considering the recovery time, we characterize the conditions under which the co-operation among treatments has a positive impact on the post-operative costs. Finally, a numerical example, constructed on the basis of real data, is provided to highlight the main features of our model.