Priority Scheme Research Articles

Coordinated Control Method for Trams on Urban Arterial

To improve the operation efficiency of the trams on the arterial, a green-wave coordinated control scheduling method for trams at intersections is proposed. The influence of the tram on the green wave programming model is analyzed, and the calculation formula of the intersection distance in the programming model is amended. Tram priority signal control system is introduced, including the absolute priority and the relative priority. Combined with these two priority schemes, according to the type of intersection and the time when the tram arrives at the intersection, the tram priority control strategy is designed. Then the position of the tram detector is studied. According to the regularity of tram’s operation, the appropriate interval between the departure times of trams is proposed to prevent multiple trams arriving within the same traffic signal period. Finally, the microscopic traffic simulation software VISSIM is used to establish the coordination control model of the tram line in Huaian city, in order to validate the proposed method.

Reimbursement policy in a healthcare system with priorities: fee for priority versus bundled priority

Abstract This paper studies a healthcare system under two priority charging schemes. The first is a fee-for-priority (FFP) scheme under which the patients can choose to buy the priorities or not at their admission or readmission to the healthcare provider (HCP). The second is a bundled priority (BP) scheme under which the HCP receives a lump sum priority payment from patients for the entire episode of priority visits (regardless of the number of readmissions). Under both schemes, a certain proportion of revenue of the HCP (the reimbursement) is used to improve the service quality for patients. A two-stage Stackelberg game is established that captures the non-cooperative interactions between the HCP and patients, where the HCP is the leader who sets a price of priority and patients are the followers who decide whether to buy the priorities or not. We first characterize the Pareto-dominant equilibrium strategy of patients under the FFP and BP schemes, and we find that the total cost (including delay disutility and priority fee) of patients can be reduced if the patient pool is large. Although patients' minimum cost, including waiting cost and priority payment, is obtained under both the FFP and BP schemes, the prices are more flexible under the former than the latter. Finally, we demonstrate that implementing the FFP scheme can induce higher social welfare than the BP scheme.

Establishment of taxi priority scheme model based on priority queuing system

With the continuous development of China’s economy, the construction of civil aviation engineering has become a major topic in China. Once again, there is a great lack of research on how to give passengers priority to return to the airport. Based on the analysis data of three representative airport passengers taking taxis, this paper establishes the priority scheme model based on the priority queuing system. Finally, by establishing the “priority function” model and quantifing the priority index, a feasible “priority” arrangement scheme is obtained. It is found that the professionalism, taxi drivers who have carried long-distance passengers are more likely to gain more profits by staying in the urban area, and the taxi drivers who have carried passengers for a short distance back to the airport to continue carrying passengers may reduce the time cost consumption Through the guidance and feasibility evaluation of how to give priority to taxi drivers based on the mathematical model, it can help the airport management department to formulate the optimization scheme scientifically and effectively, improve the working enthusiasm of taxi drivers and the travel efficiency of passengers, which has certain guiding significance for the scientific and efficient management of the airport.

Channel Allocation with MIMO in Cognitive Radio Network

The bulk volume and diverse data generated by Smart grid applications require use of Cognitive Radio (CR) technology for efficient handling. The CR technology proved out to be the most efficient technology which improves spectral utilization of any wireless network. The work in this paper is on the assignment of spectrum to the secondary users when primary user are not using. The work uses hybrid of CR and MIMO technology with clustering of gate ways, the channel allocation is done by taking real time environment in consideration. In this paper, three assignment schemes are proposed fair (F-MIMO) scheme, priority (P-MIMO) scheme and small clusters (CC-MIMO). The F-MIMO is used in low traffic condition, when all the HGWs sends the periodic data. The P-MIMO instead of reserving channels for priority user’s places non priority users in buffer in conditions when no vacant channel is available for priority users, this scheme is used in moderate traffic conditions. For the high traffic load, CC-MIMO provides priority and also borrows channels from nearby gate ways. The simulations are performed in three clusters. The simulations are done under moderate traffic using P-MIMO to compare utility of gateway with sensing bandwidth using different sensing costs. The proposed three schemes are compared in fairness and user rewards in both scenarios when borrowing is allowed and not allowed. The CC-MIMO performed optimal as compared to F-MIMO and P-MIMO which are comparable to other schemes in literature. The number of channel allocations and maximum sum reward are simulated with respect to the number of users in presence of priority users.

Optimal spatial priority scheme of urban LID-BMPs under different investment periods

The optimal spatial layout of low impact development best management practices (LID-BMPs) can be used to inform LID-BMP construction to prioritize resources to achieve the highest comprehensive benefits. An objective decomposition algorithm is designed to decompose the control objectives of total rainwater runoff, peak discharge, pollution reduction and rainwater utilization for each pixel of a raster image. A type selection algorithm is then designed to optimize the types of LID-BMPs deployed in each pixel. The most suitable positions for the construction of LID-BMPs are identified using a topographic index model to determine spatial priority level of LID-BMP construction sequence. A multi-objective model, including the maximum average reduction ratios of runoff and pollution and minimum total cost, is constructed. An adaptive differential evolution algorithm (ADEA) is designed to solve the multi-objective optimization problem. The optimal grid-based priority scheme is obtained for high-resolution spatial planning. It is shown that the most suitable positions for implementing LID-BMPs are located in regions with negative soil moisture deficits. Optimal total cost and reduction ratios of runoff and pollution to construct LID-BMPs in Yinchuan, China are $49,463,516, and 0.46 and 0.38 in the first priority scheme; $50,920,496, and 0.74 and 0.62 in the second priority scheme; and $99,207,806, and 0.92 and 0.86 in the third priority scheme. The optimal spatial priority schemes of LID-BMPs obtained from the ADEA can maintain the maximum runoff and pollution controls under different investment periods.

Dual priority: a real‐time and integrated, device‐and‐network‐centric wireless network selection

Over the last 5–7 years, with the proliferation of mobile computing devices, there has been a tremendous increase in data usage by mobile subscribers. This has quite often resulted in network congestion, forcing the operators to either increase the available bandwidth or reduce the data-rate per subscriber. To overcome this problem, network operators have been deploying different radio access networks, including Wi-Fi and small cells across their coverage areas. In order to remain always best connected, several techniques have been proposed over the period for efficient network selection. All these techniques can be broadly categorised into either device-centric or network-centric solutions. However, both device-centric and network-centric solutions have their disadvantages. In this study, a ‘dual priority’ scheme is proposed and developed that takes into account the preferences of both the subscribers and the network operator. Notably, the proposed ‘dual priority’ scheme offers a combined decision for the efficient handover of subscribers from cellular to Wi-Fi. In this work, every device has its own mechanism of ranking its preferred networks, after which the network takes the decision for offload based on the preferences and its resource availability. It has been observed that the proposed dual priority scheme results in up-to three times reduction in the time taken for offloading decision as compared to state-of-the-art network-centric solutions.

Simulation of condensation unit in ASPEN PLUS

The article discusses the scheme of deep utilization of the heat of flue gases. It has been established that in boiler units operating on natural gas, the only way to significantly improve the use of fuel is to deeply cool the combustion products to a temperature at which it is possible to condense the maximum possible portion of the fumes contained in the gases. To analyze the main energy indicators of the condensing unit and optimize its operating modes, a priority scheme was simulated in Aspen Plus. In this scheme, there are tees, heat exchangers and a reactor (boiler furnace). The configuration of tees (mixers) is carried out by setting the costs or fractions of two flows entering or leaving the element. The boiler furnace is modeled as a Gibbs reactor, which calculates the chemical and thermodynamic equilibrium by minimizing the difference in the Gibbs energy of the products and the starting materials. Using the Aspen Plus computer program, the condensation unit circuit was simulated at the PTVM-100 boiler unit with the specification of the optimal operating parameters of material flows and heat exchange equipment. The calculations show that when using a condensing boiler, a triple energy effect is achieved: the physical heat of the flue gases is used; the latent heat of vaporization released during condensation is used; the condensate released from the flue gases is used.

Some Parameterized Dynamic Priority Policies for Two-Class M/G/1 Queues

Completeness of a dynamic priority scheduling scheme is of fundamental importance for the optimal control of queues in areas as diverse as computer communications, communication networks, supply/value chains, and manufacturing systems. Our first main contribution is to identify the mean waiting time completeness as a unifying aspect for four different dynamic priority scheduling schemes by proving their completeness and equivalence in two-class M/G/1 queues. These dynamic priority schemes are earliest due date based, head of line priority jump, relative priority, and probabilistic priority. We discuss major challenges in extending our results to three or more classes. In our second main contribution , we characterize the optimal scheduling policies for the case studies in different domains by exploiting the completeness of the above dynamic priority schemes. The major theme of the second main contribution is resource allocation/optimal control in revenue management problems for contemporary systems such as cloud computing, high performance computing, ans so forth, where congestion is inherent. Using completeness and the theoretically tractable nature of relative priority policy, we study the impact of approximation in a fairly generic data network utility framework. Next, we simplify a complex joint pricing and scheduling problem for a wider class of scheduling policies.

An enhanced geographical routing protocol based on multi-criteria decision making method in mobile ad-hoc networks

Since the traditional geographical routing protocol and its variants use only single metric in routing process, they cannot handle with several problems such as congestion, network holes and link loss. To solve these problems, multi-metric geographical routing protocol have been proposed, however, most of them cannot adaptively change their forwarding policy according to network conditions because they fail to define the relationship or priorities between multiple metrics. To address this limitations, in this paper, we apply multi-criteria decision making (MCDM) method to the geographical routing protocol to accommodate multiple metrics in a logical way. In addition, we propose a new dynamic priority scheme to select the most suitable next hop by differentiating the priorities based on the network environment. Simulation results prove that our approach can achieve better performance than existing geographical routing protocols in the aspects of packet delivery ratio, end-to-end delay and routing overhead.

Modeling and analysis of cognitive radio networks with different channel access capabilities of secondary users

Cognitive radio technology deals with the problem of spectrum scarcity. Such technology allows the secondary users (SUs) to access the primary users’s (PUs) channels without causing harmful interference to the PU’s transmission. In this paper, a novel multi-class SU cognitive radio model is introduced where each SU class has the ability to sense and operate on a subset of the network channels. Such multi-class SUs’ network could exist due to hardware limitations or network regulations. The model is analysed based on the mixed preemption/nonpreemption resume priority M/M/1 queueing model. First, the analysis is carried out assuming no priority between the SU classes. Next, a priority scheme is introduced to balance the performance between the different classes. The numerical results show the delay performance trade-off between the different classes and the overall delay enhancement to the network after prioritizing the classes. Moreover, comparative studies to related work in literature and simulation results for the effect of sensing errors on SU and PU networks are introduced. Based on these results, it is recommended to apply the priority-based model for low and medium PU’s loads when the system time is considered as a performance metric. As far as we know, the case of different channel access capabilities between the SUs has not been analysed in literature before.

Changing Trends in Penetrating Keratoplasty Indications between 2011 and 2018 – Histopathology of 2123 Corneal Buttons in a Single Center in Germany

ABSTRACT Purpose: To analyse the changing trends in penetrating keratoplasty indications between January 2011 and December 2018, at the Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany. Patients and Methods: This is a retrospective review of 2123 corneal buttons of 1776 patients (1993 eyes, 56.0% males, age at the time of surgery 57.6 ± 18.7 years), who underwent penetrating keratoplasty (PKP) between January 2011 and December 2018. The classification was performed based on histological analysis and using the priority scheme of Brady et al., supplemented by a group of “failed endothelial keratoplasty grafts”. Our groups were the following: pseudophakic or aphakic bullous keratopathy, regraft, failed endothelial keratoplasty graft, acute necrotizing and ulcerative keratitis, keratoconus, Fuchs’ dystrophy, corneal dystrophy other than Fuchs’, corneal scars and other diagnoses. Results: Between 2011 and 2018, keratoconus was the leading indication for PKP in 455 (21.5%) cases, followed by acute necrotizing and ulcerative keratitis in 384 (18.1%), regraft in 367 (17.3%), corneal scars in 350 (16.5%), pseudophakic or aphakic bullous keratopathy in 225 (10.6%), Fuchs’ dystrophy in 194 (9.1%), other diagnoses in 64 (3.0%), corneal dystrophy other than Fuchs’ in 52 (2.4%), and failed endothelial keratoplasty graft in 32 (1.5%) cases. Conclusions: With the introduction of posterior lamellar keratoplasty, keratoconus remains the leading PKP indication in our center with excimer laser-trephination on a routine basis. A trend towards increasing numbers can be observed regarding acute necrotizing and ulcerative keratitis patients and regrafts. However, the incidence of Fuchs’ dystrophy decreased dramatically within PKP patients, with the introduction of posterior lamellar keratoplasty.

Identifying barriers to implementation of local transport policy – Lessons learned from case studies on bus policy implementation in Great Britain

Previous work by the authors has addressed the issue of local bus policy implementation in Britain outside London by studies of local transport documents, survey and interviews of local transport officers working in local authorities. The findings from these studies highlight that some of the key elements to successful implementation could be understood in more depth by taking a case study approach. This paper analyses four case studies of the implementation of specific bus policy measures in four different cities in Great Britain: the Quality Contract Scheme (QCS) in Tyne and Wear, the Fastlink Scheme in Glasgow, a Bus Priority Scheme in Solihull and a Smart Ticketing Scheme in Dundee. The findings in this paper show that policy champions, collaboration and interaction help to build a relationship between the parties involved, ensure limited changes due to bureaucratic power and changes to the policy, and help to overcome opposition, conflict and ambiguities. It is important that those involved in the policy process are provided with relevant training, supervision and support to help overcome the staffing difficulties and to deal with barriers external to the implementing organisation such as economic, social and political conditions.

Developing a composite indicator to prioritize tree planting and protection locations

Trees provide numerous ecosystem services to benefit human health, and many cities have launched tree planting and management programs to increase tree populations and optimize tree locations through diverse tree priority schemes. Existing tree priority schemes are typically local-specific, expert-driven, and tree-planting-focused. In this study, a framework that captures interactions among the environment, tree and human demographic information is built. This framework provides a composite indicator, namely a tree priority planting or priority protection index (PPI), that can be integrated within a decision support system such as i-Tree Landscape to provide nationally consistent and locally relevant ways to strategically optimize tree planting and management locations across the entire United States. Three scenarios with the human health concerns are tested in a case study of New York City. The analyses are conducted at the census block group scale that is the finest-level scale available at i-Tree Landscape. The resulting PPI maps are analyzed using spatial statistics and compared against each other to investigate the impacts of alternative investments of limited public resources. The results show that: (1) tree priority patterns change greatly with alternative objectives; (2) adding more indicators to build PPIs lead to more diverse tree priority patterns as high (or low) values of different indicators are often not geographically coincident; (3) incorporating more indicators may not necessarily provide more useful information because the influences of individual indicators may be reduced and diluted by a higher level of aggregation; and (4) disaggregating PPIs may reveal corresponding contributions of individual indicators. Applying the proposed framework to build PPIs has important implications for tree priority effort, scientific exploration, education, and public engagement.

Evaluation of Asia and Decolonization in the US Press

No research in the colonial system issues during the Cold War would be complete without studying the press of the participating parties. In order to give a detailed analysis of the international relationships in terms of the global transformations from an American point of view, the article explores relevant newspaper articles published after the World War II. It shows changes concerning priority schemes as viewed in American social discourse during 1945. Roosevelt’s plan for the dismantling of the colonial empires was gradually replaced with less radical plans, which presupposed using the colonial experience for foreign policy of the USA. The materials of the American press of 1945 dedicated to the search for the most effective strategy of building relations with both colonial empires and dependent territories demonstrate, among other things, a steady interest of American mass media in negative and positive experience of colonial policy. Thus, in the American public discourse of late 1945 emerged several new approaches towards evaluation of the prospects of the colonial system. The first approach: retention of all colonial empires, especially in the key points of the after-war world (Middle East, Indochina, Northern Africa). The second approach: retention of the British colonial empire capable of controlling (with the aid from the USA) the Mediterranean area, the Middle East, and the South-Eastern Asia; which would address two tasks, namely provision of valuable raw materials for the American economy, and control over rebels and national liberation forces. The third approach: replacement of colonial empires with American military presence in order to solve the same problems.

Share or Solo? Individual and Social Choices in Ride-Hailing

Ride-hailing platforms offer riders pooling services to share rides with other riders. The introduction of shared rides mitigates the driver shortage and reduces rider wait times, especially in rush hours, but it may compromise riders' privacy, space, and security. We study a queueing model in which riders wait for drivers and choose whether to join the queue and if joining, whether to take a shared or solo ride without observing the real-time system congestion. In the case of a shared ride being chosen, the rider may need to wait for another fellow rider to carpool. We analyze and compare the choices by decentralized riders and the centralized social planner of joining rates and sharing probabilities, under First-In-First-Out (FIFO) and Priority-For-Sharing (PFS) service disciplines. We discover that, under the FIFO discipline, self-interested riders in equilibrium always under-share, compared to the socially optimal solution. This leads to under-join behavior by riders due to thinner effective system capacity compared to that of the socially optimal system. In contrast, under the PFS discipline, riders may over-share to gain priority over solo riders, regardless of the negative sharing externality. Nonetheless, in equilibrium, the social planner can induce decentralized riders to achieve the socially optimal joining rate by charging a toll and to achieve the socially optimal sharing probability by appropriate social (e.g., educational), monetary, or priority schemes. Lastly, we conduct a numerical study with the ride-hailing data of Chicago in August 2019. Comparing the empirical sharing behavior with the socially optimal solution from our calibrated model, we observe that the practical sharing fraction for trips originated from residential areas (resp., downtown) is smaller (resp., greater) than the imputed socially-optimal one during morning rush hours, and vice versa during evening rush hours.

Decision-Based Cooperative Spectrum Sensing Using Random Medium-Access Sequential Reporting

Sequential reporting has the potential of reducing the duration of the reporting phase of the cooperative spectrum sensing (CSS) schemes, thereby increasing the overall system throughput. In this article, we study decision-based CSS using random medium-access sequential reporting and a K-out-of-M decision rule at the fusion center. Closed-form expressions are derived for the detection and false alarm probabilities as well as the average reporting time of two early termination sequential reporting schemes, assuming a reporting channel shared with the primary user (PU). Furthermore, a heuristic energy-based reporting priority scheme that favors cognitive radio (CR) terminals based on their capacity to detect the PU is proposed. Computer simulations are used to assess the accuracy of the derived expressions and to evaluate the proposed heuristic reporting priority scheme.

Quality of Service Provisioning for Heterogeneous Services in Cognitive Radio-Enabled Internet of Things

The Internet of Things (IoT) is a network of interconnected objects, in which every object in the world seeks to communicate and exchange information actively. This exponential growth of interconnected objects increases the demand for wireless spectrum. However, providing wireless channel access to every communicating object while ensuring its guaranteed quality of service (QoS) requirements is challenging and has not yet been explored, especially for IoT-enabled mission-critical applications and services. Meanwhile, Cognitive Radio-enabled Internet of Things (CR-IoT) is an emerging field that is considered the future of IoT. The combination of CR technology and IoT can better handle the increasing demands of various applications such as manufacturing, logistics, retail, environment, public safety, healthcare, food, and drugs. However, due to the limited and dynamic resource availability, CR-IoT cannot accommodate all types of users. In this paper, we first examine the availability of a licensed channel on the basis of its primary users' activities (e.g., traffic patterns). Second, we propose a priority-based secondary user (SU) call admission and channel allocation scheme, which is further based on a priority-based dynamic channel reservation scheme. The objective of our study is to reduce the blocking probability of higher-priority SU calls while maintaining a sufficient level of channel utilization. The arrival rates of SU calls of all priority classes are estimated using a Markov chain model, and further channels for each priority class are reserved based on this analysis. We compare the performance of the proposed scheme with the greedy non-priority and fair proportion schemes in terms of the SU call-blocking probability, SU call-dropping probability, channel utilization, and throughput. Numerical results show that the proposed priority scheme outperforms the greedy non-priority and fair proportion schemes.

An efficient packet image transmission based on texture content for border side security using sensor networks

In surveillance, several algorithms are used to extract meaningful information from an image captured. In the presence of intrusion, cameras will transmit captured images to the sink node via other intermediate nodes. Since, WSNs operate with limited resources; utilisation of resource is needed while processing and transporting images. As the node doesn't need whole image, prioritisation is one of the methods to utilise the available resource. It will prioritise images from its macro-blocks dynamically. Here the camera is attached in sensor nodes, which forms wireless multimedia sensor networks (WMSN). It applies an encoding scheme at the source node by naming the blocks as 'important' or 'not-important' based on the information they contain. Here image texture and spectral feature is used as priority measures to weight importance of macro-blocks by their GLCM properties. Experimental result discloses that priority scheme adapts itself to the quality requirements while reducing the bandwidth comparatively.

An efficient packet image transmission based on texture content for border side security using sensor networks

In surveillance, several algorithms are used to extract meaningful information from an image captured. In the presence of intrusion, cameras will transmit captured images to the sink node via other intermediate nodes. Since, WSNs operate with limited resources; utilisation of resource is needed while processing and transporting images. As the node doesn't need whole image, prioritisation is one of the methods to utilise the available resource. It will prioritise images from its macro-blocks dynamically. Here the camera is attached in sensor nodes, which forms wireless multimedia sensor networks (WMSN). It applies an encoding scheme at the source node by naming the blocks as 'important' or 'not-important' based on the information they contain. Here image texture and spectral feature is used as priority measures to weight importance of macro-blocks by their GLCM properties. Experimental result discloses that priority scheme adapts itself to the quality requirements while reducing the bandwidth comparatively.

MARKETS OF GEORGIAN AGRO-FOOD PRODUCTS AND EXPORT STIMULATING ECONOMIC POLICY

The article substantiates the importance of the development of food markets in the solution of food security problem. It is argued that the tendency of demand for food has an increasing trend and the development of food markets still remains one of the most important challenges of contemporary world. The study analyzes the markets of Georgian agro- food products and studies the modern challenges in these markets. Comparative analysis of Georgian and Spanish food markets is conducted. The article estimates the positive and negative trends of export of Georgian agro-food products as well as the possibilities of diversification of products in the food markets. According to “The Impact-Immediacy” matrix the hindering factors of Georgian agro products export are identified. Using the «Priority Scheme» the priorities of economic policy stimulating the export of agro-food products are revealed. In terms of geographical orientation of the export the possibilities of diversification of food markets are discussed, especially in European markets. The conclusion is made that, in general, European food market is characterized by the growing tendency. However, in these markets there is no similar tendency for Georgian agro-food products. According to the study of the share of Georgian products and export growth rates in different countries the positive correlation between these variables is determined. But this circumstance is not considered to be sufficient for the positive impact on the economic growth. The conclusion is made that using effective mechanisms of export stimulation allows the diversification of export of Georgian agro products on the traditional but growing food markets on the one hand and on the other hand the expansion of geographical area of export markets.