On the Busy Period in One Finite Queue of M/G/1 Type with Inactive Orbit

The paper deals with a single server finite queuing system where the customers, who failed to get service, are temporarily blocked in the orbit of inactive customers. This model and its variants have many applications, especially for optimization of the corresponding models with retrials. We analyze the system in non-stationary regime and, using the discrete transformations method study, the busy period length and the number of successful calls made during it. ACM Computing Classification System (1998): G.3, J.7.

Better queue management in a busy public hospital of a developing country without appointment system::an application using data envelopment analysis

Queuing is a key efficiency criterion in any service industry, including Healthcare. Almost all queue management studies are dedicated to improving an existing Appointment System. In developing countries such as Pakistan, there are no Appointment Systems for outpatients, resulting in excessive wait times. Additionally, excessive overloading, limited resources and cumbersome procedures lead to over-whelming queues. Despite numerous Healthcare applications, Data Envelopment Analysis (DEA) has not been applied for queue assessment. The current study aims to extend DEA modelling and demonstrate its usefulness by evaluating the queue system of a busy public hospital in a developing country, Pakistan, where all outpatients are walk-in; along with construction of a dynamic framework dedicated towards the implementation of the model. The inadequate allocation of doctors/personnel was observed as the most critical issue for long queues. Hence, the Queuing-DEA model has been developed such that it determines the ‘required’ number of doctors/personnel. The results indicated that given extensive wait times or length of queue, or both, led to high target values for doctors/personnel. Hence, this crucial information allows the administrators to ensure optimal staff utilization and controlling the queue pre-emptively, minimizing wait times. The dynamic framework constructed, specifically targets practical implementation of the Queuing-DEA model in resource-poor public hospitals of developing countries such as Pakistan; to continuously monitor rapidly changing queue situation and display latest required personnel. Consequently, the wait times of subsequent patients can be minimized, along with dynamic staff scheduling in the absence of appointments. This dynamic framework has been designed in Excel, requiring minimal training and work for users and automatic update features, with complex technical aspects running in the background. The proposed model and the dynamic framework has the potential to be applied in similar public hospitals, even in other developing countries, where appointment systems for outpatients are non-existent.

Optimization of adaptive traffic signal control with transit signal priority at isolated intersections using parallel genetic algorithms

Optimization of adaptive traffic signal timing is one of the most complex problems in traffic control systems. This dissertation presents a new method that applies the parallel genetic algorithm (PGA) to optimize adaptive traffic signal control in the presence of transit signal priority (TSP). The method can optimize the phase plan, cycle length, and green splits at isolated intersections with consideration for the performance of both the transit and the general vehicles. Unlike the simple genetic algorithm (GA), PGA can provide better and faster solutions needed for real-time optimization of adaptive traffic signal control. ^ An important component in the proposed method involves the development of a microscopic delay estimation model that was designed specifically to optimize adaptive traffic signal with TSP. Macroscopic delay models such as the Highway Capacity Manual (HCM) delay model are unable to accurately consider the effect of phase combination and phase sequence in delay calculations. In addition, because the number of phases and the phase sequence of adaptive traffic signal may vary from cycle to cycle, the phase splits cannot be optimized when the phase sequence is also a decision variable. A "flex-phase" concept was introduced in the proposed microscopic delay estimation model to overcome these limitations. ^ The performance of PGA was first evaluated against the simple GA. The results show that PGA achieved both faster convergence and lower delay for both under- or over-saturated traffic conditions. A VISSIM simulation testbed was then developed to evaluate the performance of the proposed PGA-based adaptive traffic signal control with TSP. The simulation results show that the PGA-based optimizer for adaptive TSP outperformed the fully actuated NEMA control in all test cases. The results also show that the PGA-based optimizer was able to produce TSP timing plans that benefit the transit vehicles while minimizing the impact of TSP on the general vehicles. The VISSIM testbed developed in this research provides a powerful tool to design and evaluate different TSP strategies under both actuated and adaptive signal control. ^

Realization of Differentiated Quality of Service for Wideband Code Division Multiple Access Core Network

The development of 3G (the 3rd generation telecommunication) value-added services brings higher requirements of Quality of Service (QoS). Wideband Code Division Multiple Access (WCDMA) is one of three 3G standards, and enhancement of QoS for WCDMA Core Network (CN) becomes more and more important for users and carriers. The dissertation focuses on enhancement of QoS for WCDMA CN. The purpose is to realize the DiffServ (Differentiated Services) model of QoS for WCDMA CN. Based on the parallelism characteristic of Network Processors (NPs), the NP programming model is classified as Pool of Threads (POTs) and Hyper Task Chaining (HTC). In this study, an integrated programming model that combines both of the two models was designed. This model has highly efficient and flexible features, and also solves the problems of sharing conflicts and packet ordering. We used this model as the programming model to realize DiffServ QoS for WCDMA CN. ^ The realization mechanism of the DiffServ model mainly consists of buffer management, packet scheduling and packet classification algorithms based on NPs. First, we proposed an adaptive buffer management algorithm called Packet Adaptive Fair Dropping (PAFD), which takes into consideration of both fairness and throughput, and has smooth service curves. Then, an improved packet scheduling algorithm called Priority-based Weighted Fair Queuing (PWFQ) was introduced to ensure the fairness of packet scheduling and reduce queue time of data packets. At the same time, the delay and jitter are also maintained in a small range. Thirdly, a multi-dimensional packet classification algorithm called Classification Based on Network Processors (CBNPs) was designed. It effectively reduces the memory access and storage space, and provides less time and space complexity. ^ Lastly, an integrated hardware and software system of the DiffServ model of QoS for WCDMA CN was proposed. It was implemented on the NP IXP2400. According to the corresponding experiment results, the proposed system significantly enhanced QoS for WCDMA CN. It extensively improves consistent response time, display distortion and sound image synchronization, and thus increases network efficiency and saves network resource.^

Understanding the relationship between the Talented Twenty program and college aspirations for high ranking students at a high priority school

Percentage plans such as the Talented Twenty program purport to assist and motivate high ranking students to attend college and grant access to higher education. This type of plan is particularly important to students enrolled in high priority schools who might not view themselves as potential college students. This study examined the relationship between Florida’s Talented Twenty program that begins intervention with juniors and the college aspirations for high ranking students at a high priority school. Numerous studies have established that increased levels of education lead to higher salaries, career mobility, and an increased quality of life (e.g., Bowen, 1997; Leslie & Brinkman 1988; Pascarella & Terenzini, 1991, Swail, 2000). Given the importance of students’ decisions regarding whether or not they will attend college, understanding how and when they make decisions about attending college is important for them, their parents, advisors, and educational administrators. This research examined students’ perceptions and insights via interviews. The overarching research question was: How do high ranking high school students attending a high priority school in a south Florida district perceive their college opportunities? Sixteen high ranking students, grades nine – 12 from a high priority school in Miami-Dade County participated in the study. Participants were identified by a school counselor and individual semi structured interviews were conducted at the school. Utilizing a student development theoretical framework developed by Hossler and Gallagher (1987) that centered on students’ predisposition, search strategies and choices, data were organized and emergent themes analyzed. The analysis of the data revealed that in alignment with the framework (a) parents were the strongest influence in the development of these students’ college aspirations, (b) these students formalized their higher education plans between eighth and 10th grade, (c) these students actively engaged in academic searches and learning opportunities that increased their chances to be admitted into college, and (d) there was no relationship between knowledge regarding the Talented Twenty program and their educational decisions. This study’s findings suggest that interventions and programs intended to influence the educational aspirations of students are more likely to succeed if they take place by the eighth or ninth grade.

Descriptions of Scottish Priority Marine Features (PMFs).

Background The seas around Scotland are rich and diverse – Scotland’s position at the edge of the continental shelf, the long coastline, large area of sea and the mixing of warm and coldwater currents combine to make its waters a special place for marine wildlife and habitats. Scotland has over 18,000 km of coastline and its inshore and offshore areas are among the largest of any EU country, representing 13% of all European seas. Scotland’s seas are of outstanding scenic, historical and cultural value and are part of the national identity at home and abroad. The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers and duties to ensure that our seas are managed sustainably for future generations, integrating the economic growth of marine industries with the need to protect these assets. Measures to conserve Scotland’s marine natural heritage are based on a three pillar approach, with action at the wider seas level (e.g. marine planning or sectoral controls); specific species conservation measures (e.g. improved protection for seals); and through site protection measures - the identification of new Marine Protected Areas (MPAs). To help target action under each of the three pillars, Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have generated a focused list of habitats and species of priority conservation importance - the Priority Marine Features (PMFs). The aim of the current study was to produce a descriptive catalogue of the Scottish PMFs (including component habitats and species where appropriate) to serve as a reference for future nature conservation action. Whilst derived from available existing accounts, the succinct 1-page descriptions are written from a Scottish perspective, refining, but clearly linking to more generic UK, EC or OSPAR (Oslo and Paris Commission) commentary. Available information on the geographic distribution of the features was collated as part of the project and a summary map is provided in each description. Main findings  This project has generated a descriptive catalogue of the 81 PMFs that have been identified in the seas around Scotland (out to the limit of the UK continental shelf). The list comprises 26 broad habitats (e.g. burrowed mud), seven low or limited mobility species (e.g. ocean quahog) and 48 mobile species, including fish (e.g. blue ling) and marine mammals (e.g. minke whale).  Information on the distribution of the PMFs was collated within a Geographic Information System (GIS). This is the first time that data about such a diverse range of Scottish marine nature conservation interests have been compiled within a single repository. These data have and will be used in conjunction with other contextual base-mapping to inform the development of nature conservation advice and commentary (e.g. in the production of the Scotland’s Marine Atlas - Baxter et al., 2011).  The feature distribution mapping used in the production of this report is being made available to view online via the National Marine Plan Interactive web portal (NMPi - http://www.gov.scot/Topics/marine/seamanagement/nmpihome). As new or refined data on Scottish PMFs become available, these will be fed into updates to the project geodatabase and NMPi.

Descriptions of Scottish Priority Marine Features (PMFs).

Background The seas around Scotland are rich and diverse – Scotland’s position at the edge of the continental shelf, the long coastline, large area of sea and the mixing of warm and coldwater currents combine to make its waters a special place for marine wildlife and habitats. Scotland has over 18,000 km of coastline and its inshore and offshore areas are among the largest of any EU country, representing 13% of all European seas. Scotland’s seas are of outstanding scenic, historical and cultural value and are part of the national identity at home and abroad. The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers and duties to ensure that our seas are managed sustainably for future generations, integrating the economic growth of marine industries with the need to protect these assets. Measures to conserve Scotland’s marine natural heritage are based on a three pillar approach, with action at the wider seas level (e.g. marine planning or sectoral controls); specific species conservation measures (e.g. improved protection for seals); and through site protection measures - the identification of new Marine Protected Areas (MPAs). To help target action under each of the three pillars, Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) have generated a focused list of habitats and species of priority conservation importance - the Priority Marine Features (PMFs). The aim of the current study was to produce a descriptive catalogue of the Scottish PMFs (including component habitats and species where appropriate) to serve as a reference for future nature conservation action. Whilst derived from available existing accounts, the succinct 1-page descriptions are written from a Scottish perspective, refining, but clearly linking to more generic UK, EC or OSPAR (Oslo and Paris Commission) commentary. Available information on the geographic distribution of the features was collated as part of the project and a summary map is provided in each description. Main findings  This project has generated a descriptive catalogue of the 81 PMFs that have been identified in the seas around Scotland (out to the limit of the UK continental shelf). The list comprises 26 broad habitats (e.g. burrowed mud), seven low or limited mobility species (e.g. ocean quahog) and 48 mobile species, including fish (e.g. blue ling) and marine mammals (e.g. minke whale).  Information on the distribution of the PMFs was collated within a Geographic Information System (GIS). This is the first time that data about such a diverse range of Scottish marine nature conservation interests have been compiled within a single repository. These data have and will be used in conjunction with other contextual base-mapping to inform the development of nature conservation advice and commentary (e.g. in the production of the Scotland’s Marine Atlas - Baxter et al., 2011).  The feature distribution mapping used in the production of this report is being made available to view online via the National Marine Plan Interactive web portal (NMPi - http://www.gov.scot/Topics/marine/seamanagement/nmpihome). As new or refined data on Scottish PMFs become available, these will be fed into updates to the project geodatabase and NMPi.

Rathbun Lake Special Project: BMPs for priority land in Targeted Sub-Watershed 2012 1221-010, Final Report 2013-2061,

The Rathbun Land and Water Alliance and partners have undertaken a highly effective approach to water quality protection through the Rathbun Lake Special Project. This approach is achieving a significant reduction in the sediment and phosphorus that impair water quality in Rathbun Lake and its tributaries as a result of the targeted application of best management practices (BMPs) for priority land in the watershed. This project application proposes to assist landowners to apply BMPs that will reduce sediment and phosphorus delivery from priority land in three targeted sub-watersheds as part of the Rathbun Lake Special Project. Features of this project are: (1) use of geographic information system (GIS) analysis to identify priority land that requires BMPs; (2) assistance for landowners to apply BMPs for 1,200 acres that will reduce the annual delivery of sediment by 1,800 tons and phosphorus by 6,000 pounds; (3) evaluation of the benefits from BMP application using GIS analysis and water quality monitoring; and (4) watershed outreach activities that encourage landowners to apply BMPs for priority land to protect water quality.

Rathbun Lake Special Project BMPs for Priority Land in Targeted Sub-Watersheds 2012: Final Report: 1221-010, 2013-2016, June 27, 2016

The Rathbun Land and Water Alliance and partners have undertaken a highly effective approach to water quality protection through the Rathbun Lake Special Project. This approach is achieving a significant reduction in the sediment and phosphorus that impair water quality in Rathbun Lake and its tributaries as a result of the targeted application of best management practices (BMPs) for priority land in the watershed. This project application proposes to assist landowners to apply BMPs that will reduce sediment and phosphorus delivery from priority land in three targeted sub-watersheds as part of the Rathbun Lake Special Project. Features of this project are:(1) use of geographic information system (GIS) analysis to identify priority land that requires BMPs;(2) assistance for landowners to apply BMPs for 1,200 acres that will reduce the annual delivery of sediment by 1,800 tons and phosphorus by 6,000 pounds;(3) evaluation of the benefits from BMP application using GIS analysis and water quality monitoring; and (4) watershed outreach activities that encourage landowners to apply BMPs for priority land to protect water quality.

Setting the agenda for dental education in Scotland: a priority setting exercise including multiple stakehiolders

Introduction The Scottish Oral Health Research Collaboration identified dental education research (DER) as a key strand of their strategy,(1) leading to the formation of the Dental Education Research Group. The starting point for this group was to understand various stakeholders’ perceptions of research priorities, yet no existing studies were found. The aim of the current study was to identify DER priorities for Scotland in the next 3-5 years. Methods The study utilised a similar methodology to that of Dennis et al,(2) in medical education. Data were collected sequentially using two online questionnaires with multiple dental stakeholders represented at undergraduate and postgraduate levels across urban and rural Scotland. 85 participants completed questionnaire 1 (qualitative) and 649 participants completed questionnaire 2 (quantitative). Qualitative and quantitative data analysis approaches were used. Results Of the 24 priorities identified, the top priorities were: role of assessments in identifying competence; undergraduate curriculum prepares for practice; and promoting teamwork within the dental team. Following factor analysis, the priorities loaded on four factors: teamwork and professionalism, measuring and enhancing performance, personal and professional development challenges, and curriculum integration and innovation. The top barriers were lack of time, funding, staff motivation, valuing of DER, and resources/ infrastructure. Discussion There were many similarities between the identified priorities for dental and medical education research2, but also some notable differences, which will be discussed. Overwhelmingly, the identified priorities in dentistry related to fitness for practice and robust assessment practices. Take home message Priority setting exercises with multiple stakeholders are an important first step in developing a national research strategy. References 1. Bagg J, Macpherson L, Mossey P, Rennie J, Saunders B, Taylor M (2010) Strategy for Oral Health Research in Scotland. Edinburgh: The Scottish Government. 2. Dennis A A, Cleland J A, Johnston P, Ker JS, Lough, M Rees CE (2014) Exploring stakeholders’ views of medical education research priorities: a national study. Medical Education, 48(11): 1078-1091.

Wildlife as a Priority in Park Development: A Study of Illinois Park Professionals

The purpose of this thesis is to consider the factors that impact decision making in city park settings, with specific emphasis given to wildlife. Additionally, professional bias was considered as a possible response determinant. Studies connecting perceptions of wildlife and Illinois park managers have been rare or nonexistent, but offer the potential for the improvement of management strategies and recreational opportunities. Data was collected using mixed methods. City recreation practitioners statewide were invited to complete a self-administered questionnaire considering wildlife as a decision-making factor in land acquisition or restoration decisions. A small follow-up sample of park managers was interviewed via telephone for further explanation of their response. Analysis of responses from questionnaires and interviews suggested that wildlife habitat is a factor in land use decision making, but is not considered one of the highest importance. Respondents identified that nuisance wildlife, access to wildlife, and public value of wildlife were also factors in decision making. Factors associated with a high-ranking of the importance of wildlife were agencies with a high number of natural area acres, a high number of overall park acreage, personnel devoted to natural area management, the presence of hiking trails, and cities with a large population. Professional bias of recreation managers was suggested via anecdotal interview data, but could not be empirically connected with wildlife-related decision-making processes, as no managers identified themselves as having completed formal wildlife-related training. As a result, management implications include separate training for both practitioners and public. This study broadens the understanding of wildlife management in city park settings, and reaffirms that further understanding of public and pracitioner values of wildlife will lead to improved land use decisions and recreationally valuable experiences.

Priorities for future intensive care research in the UK: results of a James Lind Alliance Priority Setting Partnership.

This James Lind Alliance (JLA) Priority Setting Partnership aimed to identify and prioritise unanswered questions about adult intensive care that are important to people who have been critically ill, their families, and the health professionals who care for them. Consensus techniques (modified Delphi and Nominal Group) were used to generate suggestions using online and postal surveys. Following verification and iterative editorial review, research topics were constructed from these suggestions. These topics were presented in a second online and postal survey for rating. A Nominal Group of 21 clinicians, patients and family representatives subsequently met to rank the most important research topics and produce a prioritised list. The project was coordinated by a representative Steering Group and independently overseen by the JLA. The initial survey and review of the literature generated over 1,300 suggestions. Preliminary editing and verification permitted us to encapsulate these suggestions within 151 research topics. Iterative review by members of the Steering Group produced 37 topic statements, subsequently rated by participants. Using the mode to determine importance, 19 topics were presented to the group from which a ‘top three’ intensive care research priorities were identified and a further nine topics were prioritised. By applying and adapting the JLA methodology to focus on an area of care rather than to a single disease, we have provided a means to ensure that patients, their families and professionals materially contribute to the prioritisation of intensive care research in the UK.

Queueuing system with failures and priorities

Queueing theory provides models, structural insights, problem solutions and algorithms to many application areas. Due to its practical applicability to production, manufacturing, home automation, communications technology, etc, more and more complex systems requires more elaborated models, tech- niques, algorithm, etc. need to be developed. Discrete-time models are very suitable in many situations and a feature that makes the analysis of discrete time systems technically more involved than its continuous time counterparts. In this paper we consider a discrete-time queueing system were failures in the server can occur as-well as priority messages. The possibility of failures of the server with general life time distribution is considered. We carry out an extensive study of the system by computing generating functions for the steady-state distribution of the number of messages in the queue and in the system. We also obtain generating functions for the stationary distribution of the busy period and sojourn times of a message in the server and in the system. Performance measures of the system are also provided.

Determining conservation priority areas for Palearctic passerine migrant birds in sub-Saharan Africa

Migratory bird species breeding in the Palearctic and overwintering in sub-Saharan Africa face multiple conservation challenges. As a result, many of these species have declined in recent decades, some dramatically. We therefore used the best available database for the distribution of 68 passerine migrants in sub-Saharan Africa to determine priority regions for their conservation. After modeling each species’ distribution using BIOMOD software, we entered the resulting species distributions at a 1° × 1° grid resolution into MARXAN software. We then used several different selection procedures that varied the boundary length modifier, species penalty factor, and the inclusion of grid cells with high human footprint and with protected areas. While results differed between selection procedures, four main regions were regularly selected: (1) one centered on southern Mali; (2) one including Eritrea, central Sudan, and northern Ethiopia; (3) one encompassing southwestern Kenya and much of Tanzania and Uganda; and (4) one including much of Zimbabwe and southwestern Zambia. We recommend that these four regions become priority regions for research and conservation efforts for the bird species considered in this study.