Modeling cumulative evidence for freedom from disease with applications to BSE surveillance trials

This investigation deals with the question of when a particular population can be considered to be disease-free. The motivation is the case of BSE where specific birth cohorts may present distinct disease-free subpopulations. The specific objective is to develop a statistical approach suitable for documenting freedom of disease, in particular, freedom from BSE in birth cohorts. The approach is based upon a geometric waiting time distribution for the occurrence of positive surveillance results and formalizes the relationship between design prevalence, cumulative sample size and statistical power. The simple geometric waiting time model is further modified to account for the diagnostic sensitivity and specificity associated with the detection of disease. This is exemplified for BSE using two different models for the diagnostic sensitivity. The model is furthermore modified in such a way that a set of different values for the design prevalence in the surveillance streams can be accommodated (prevalence heterogeneity) and a general expression for the power function is developed. For illustration, numerical results for BSE suggest that currently (data status September 2004) a birth cohort of Danish cattle born after March 1999 is free from BSE with probability (power) of 0.8746 or 0.8509, depending on the choice of a model for the diagnostic sensitivity.

Evaluation of the cumulative evidence for freedom from BSE in birth cohorts

Substantial resources are used for surveillance of bovine spongiform encephalopathy (BSE) despite an extremely low detection rate, especially in healthy slaughtered cattle. We have developed a method based on the geometric waiting time distribution to establish and update the statistical evidence for BSE-freedom for defined birth cohorts using continued surveillance data. The results suggest that currently (data included till September 2004) a birth cohort of Danish cattle born after March 1999 is free from BSE with probability (power) of 0.8746 or 0.8509, depending on the choice of a model for the diagnostic sensitivity. These results apply to an assumed design prevalence of 1 in 10,000 and account for prevalence heterogeneity. The age-dependent, diagnostic sensitivity for the detection of BSE has been identified as major determinant of the power. The incorporation of heterogeneity was deemed adequate on scientific grounds and led to improved power values. We propose our model as a decision tool for possible future modification of the BSE surveillance and discuss public health and international trade implications.

Subcontract and supply enquiries in the tender process of contractors

In the tender process, contractors often rely on subcontract and supply enquiries to calculate their bid prices. However, this integral part of the bidding process is not empirically articulated in the literature. Over 30 published materials on the tendering process of contractors that talk about enquiries were reviewed and found to be based mainly on experiential knowledge rather than systematic evidence. The empirical research here helps to describe the process of enquiries precisely, improve it in practice, and have some basis to support it in theory. Using a live participant observation case study approach, the whole tender process was shadowed in the offices of two of the top 20 UK civil engineering construction firms. This helped to investigate 15 research questions on how contractors enquire and obtain prices from subcontractors and suppliers. Forty-three subcontract enquiries and 18 supply enquiries were made across two different projects with average value of 7m. An average of 15 subcontract packages and seven supply packages was involved. Thus, two or three subcontractors or suppliers were invited to bid in each package. All enquiries were formulated by the estimator, with occasional involvement of three other personnel. Most subcontract prices were received in an average of 14 working days; and supply prices took five days. The findings show 10 main activities involved in processing enquiries and their durations, as well as wasteful practices associated with enquiries. Contractors should limit their enquiry invitations to a maximum of three per package, and optimize the waiting time for quotations in order to improve cost efficiency.

Computing journey start times with recurrent traffic conditions

n this study, the authors discuss the effective usage of technology to solve the problem of deciding on journey start times for recurrent traffic conditions. The developed algorithm guides the vehicles to travel on more reliable routes that are not easily prone to congestion or travel delays, ensures that the start time is as late as possible to avoid the traveller waiting too long at their destination and attempts to minimise the travel time. Experiments show that in order to be more certain of reaching their destination on time, a traveller has to leave early and correspondingly arrive early, resulting in a large waiting time. The application developed here asks the user to set this certainty factor as per the task in hand, and computes the best start time and route.

Transmathematical basis of infinitely scalable pipeline machines

We describe infinitely scalable pipeline machines with perfect parallelism, in the sense that every instruction of an inline program is executed, on successive data, on every clock tick. Programs with shared data effectively execute in less than a clock tick. We show that pipeline machines are faster than single or multi-core, von Neumann machines for sufficiently many program runs of a sufficiently time consuming program. Our pipeline machines exploit the totality of transreal arithmetic and the known waiting time of statically compiled programs to deliver the interesting property that they need no hardware or software exception handling.

A moving point approach to model shallow ice sheets: a study case with radially-symmetrical ice sheets

Predicting the evolution of ice sheets requires numerical models able to accurately track the migration of ice sheet continental margins or grounding lines. We introduce a physically based moving point approach for the flow of ice sheets based on the conservation of local masses. This allows the ice sheet margins to be tracked explicitly and the waiting time behaviours to be modelled efficiently. A finite difference moving point scheme is derived and applied in a simplified context (continental radially-symmetrical shallow ice approximation). The scheme, which is inexpensive, is validated by comparing the results with moving-margin exact solutions and steady states. In both cases the scheme is able to track the position of the ice sheet margin with high precision.

A moving-point approach to model shallow ice sheets: a study case with radially symmetrical ice sheets

Predicting the evolution of ice sheets requires numerical models able to accurately track the migration of ice sheet continental margins or grounding lines. We introduce a physically based moving-point approach for the flow of ice sheets based on the conservation of local masses. This allows the ice sheet margins to be tracked explicitly. Our approach is also well suited to capture waiting-time behaviour efficiently. A finite-difference moving-point scheme is derived and applied in a simplified context (continental radially symmetrical shallow ice approximation). The scheme, which is inexpensive, is verified by comparing the results with steady states obtained from an analytic solution and with exact moving-margin transient solutions. In both cases the scheme is able to track the position of the ice sheet margin with high accuracy.

Vasectomy within the public health services in Campinas, Sao Paulo, Brazil

Objective: To describe some of the characteristics of men who underwent a vasectomy in the public health network of Campinas, Sao Paulo, Brazil. Methods: A descriptive study including 202 men randomly selected from a list of all the men vasectomized between 1998 and 2004 in the public health network. Results: Most of the men were 30 years of age or older when vasectomized, had completed elementary school and had two or more children of both sexes. Most of the men came from the lowest income segment of the population: 47.6% in 1998-1999 and 61.3% in 2003-2004. Although the men knew various contraceptive methods, 51.2% reported that their partners were using combined oral contraceptives at the time of surgery. Most men initially sought information on vasectomy at health-care clinics where care was provided by a multidisciplinary team; most received counselling, however, 47.9% of the men waited more than 4 months for the vasectomy. Conclusions: The profile of the vasectomized men in this study appears to indicate that the low-income population from Campinas, Sao Paulo, Brazil has access to vasectomy; however, the waiting time for vasectomy reveals that difficulties exist in obtaining this contraceptive method in the public health service.

QoS Evaluation of BandwidthSchedulers in IPTV Networks OfferedSRD Fluid Video Traffic

Internet protocol TV (IPTV) is predicted to be the key technology winner in the future. Efforts to accelerate the deployment of IPTV centralized model which is combined of VHO, encoders, controller, access network and Home network. Regardless of whether the network is delivering live TV, VOD, or Time-shift TV, all content and network traffic resulting from subscriber requests must traverse the entire network from the super-headend all the way to each subscriber's Set-Top Box (STB).IPTV services require very stringent QoS guarantees When IPTV traffic shares the network resources with other traffic like data and voice, how to ensure their QoS and efficiently utilize the network resources is a key and challenging issue. For QoS measured in the network-centric terms of delay jitter, packet losses and bounds on delay. The main focus of this thesis is on the optimized bandwidth allocation and smooth datatransmission. The proposed traffic model for smooth delivering video service IPTV network with its QoS performance evaluation. According to Maglaris et al [5] First, analyze the coding bit rate of a single video source. Various statistical quantities are derived from bit rate data collected with a conditional replenishment inter frame coding scheme. Two correlated Markov process models (one in discrete time and one incontinuous time) are shown to fit the experimental data and are used to model the input rates of several independent sources into a statistical multiplexer. Preventive control mechanism which is to be include CAC, traffic policing used for traffic control.QoS has been evaluated of common bandwidth scheduler( FIFO) by use fluid models with Markovian queuing method and analysis the result by using simulator andanalytically, Which is measured the performance of the packet loss, overflow and mean waiting time among the network users.

PERFORMANCE EVOLUTION OF PEER TO PEER NETWORKS

This thesis work concerns about the Performance evolution of peer to peer networks, where we used different distribution technique’s of peer distribution like Weibull, Lognormal and Pareto distribution process. Then we used a network simulator to evaluate the performance of these three distribution techniques.During the last decade the Internet has expanded into a world-wide network connecting millions of hosts and users and providing services for everyone. Many emerging applications are bandwidth-intensive in their nature; the size of downloaded files including music and videos can be huge, from ten megabits to many gigabits. The efficient use of network resources is thus crucial for the survivability of the Internet. Traffic engineering (TE) covers a range of mechanisms for optimizing operational networks from the traffic perspective. The time scale in traffic engineering varies from the short-term network control to network planning over a longer time period.Here in this thesis work we considered the peer distribution technique in-order to minimise the peer arrival and service process with three different techniques, where we calculated the congestion parameters like blocking time for each peer before entering into the service process, waiting time for a peers while the other peer has been served in the service block and the delay time for each peer. Then calculated the average of each process and graphs have been plotted using Matlab to analyse the results

Simulation of Sawmill Yard Operations Using Software Agents

Bergkvist insjön AB is a sawmill yard which is capable of producing 350,000 cubic meter of timber every year this requires lot of internal resources. Sawmill operations can be classified as unloading, sorting, storage and production of timber. In the company we have trucks arriving at random they have to be unloaded and sent back at the earliest to avoid queuing up of trucks creating a problem for truck owners. The sawmill yard has to operate with two log stackers that does several tasks including transporting the logs from trucks to measurement station where the logs will be sorted into classes and dropped into pockets from pockets to the sorted timber yard where they are stored and finally from there to sawmill for final processing. The main issue that needs to be answered here is the lining up trucks that are waiting to be unload, creating a problem for both sawmill as well as the truck owners and given huge production volume, it is certain that handling of resources is top priority. A key challenge in handling of resources would be unloading of trucks and finding a way to optimize internal resources.To address this problem i have experimented on different ways of using internal resources, i have designed different cases, in case 1 we have both the log stackers working on sawmill and measurement station. The main objective of having this case is to make sawmill and measurement station to work all the time. Then in case 2, i have divided the work between both the log stackers, one log stacker will be working on sawmill and pocket_control and second log stacker will be working on measurement station and truck. Then in case 3 we have only one log stacker working on all the agents, this case was designed to reduce cost of production, as the experiment cannot be done in real-time due to operational cost, for this purpose simulation is used, preliminary investigation into simulation results suggested that case 2 is the best option has it reduced waiting time of trucks considerably when compared with other cases and it showed 50% increase in optimizing internal resources.

QoS evaluation of Bandwidth Schedulers in IPTV Networks Offered SRD Fluid Video Traffic

Internet protocol TV (IPTV) is predicted to be the key technology winner in the future. Efforts to accelerate the deployment of IPTV centralized model which is combined of VHO, encoders, controller, access network and Home network. Regardless of whether the network is delivering live TV, VOD, or Time-shift TV, all content and network traffic resulting from subscriber requests must traverse the entire network from the super-headend all the way to each subscriber's Set-Top Box (STB). IPTV services require very stringent QoS guarantees When IPTV traffic shares the network resources with other traffic like data and voice, how to ensure their QoS and efficiently utilize the network resources is a key and challenging issue. For QoS measured in the network-centric terms of delay jitter, packet losses and bounds on delay. The main focus of this thesis is on the optimized bandwidth allocation and smooth data transmission. The proposed traffic model for smooth delivering video service IPTV network with its QoS performance evaluation. According to Maglaris et al [5] first, analyze the coding bit rate of a single video source. Various statistical quantities are derived from bit rate data collected with a conditional replenishment inter frame coding scheme. Two correlated Markov process models (one in discrete time and one in continuous time) are shown to fit the experimental data and are used to model the input rates of several independent sources into a statistical multiplexer. Preventive control mechanism which is to be including CAC, traffic policing used for traffic control. QoS has been evaluated of common bandwidth scheduler( FIFO) by use fluid models with Markovian queuing method and analysis the result by using simulator and analytically, Which is measured the performance of the packet loss, overflow and mean waiting time among the network users.

A systematic review of triage-related interventions to improve patient flow in emergency departments

Background Overcrowding in emergency departments is a worldwide problem. A systematic literature review was undertaken to scientifically explore which interventions improve patient flow in emergency departments. Methods A systematic literature search for flow processes in emergency departments was followed by assessment of relevance and methodological quality of each individual study fulfilling the inclusion criteria. Studies were excluded if they did not present data on waiting time, length of stay, patients leaving the emergency department without being seen or other flow parameters based on a nonselected material of patients. Only studies with a control group, either in a randomized controlled trial or in an observational study with historical controls, were included. For each intervention, the level of scientific evidence was rated according to the GRADE system, launched by a WHO-supported working group. Results The interventions were grouped into streaming, fast track, team triage, point-of-care testing (performing laboratory analysis in the emergency department), and nurse-requested x-ray. Thirty-three studies, including over 800,000 patients in total, were included. Scientific evidence on the effect of fast track on waiting time, length of stay, and left without being seen was moderately strong. The effect of team triage on left without being seen was relatively strong, but the evidence for all other interventions was limited or insufficient. Conclusions Introducing fast track for patients with less severe symptoms results in shorter waiting time, shorter length of stay, and fewer patients leaving without being seen. Team triage, with a physician in the team, will probably result in shorter waiting time and shorter length of stay and most likely in fewer patients leaving without being seen. There is only limited scientific evidence that streaming of patients into different tracks, performing laboratory analysis in the emergency department or having nurses to request certain x-rays results in shorter waiting time and length of stay.

Patienters upplevelser av att vårdas på en akutmottagning : -en litteraturöversikt

Bakgrund: Vårdpersonalen på en akutmottagning har stora krav på sig, ansvar för många patienter och måste fatta många egna beslut, ibland med mycket kort betänketid. Vårdpersonalen möter många olika patienter med olika problem och personligheter, och måste bemöta varje patient så att denne känner sig bekräftad och sedd. Syfte: Syftet med litteraturöversikten är att undersöka patienters upplevelse av att vårdas på en akutmottagning. Metod: Artiklar till arbetet har söks i olika databaser. Aktuella artiklar har lästs och relevanta fynd har markerats, för att analyseras och sammanställa ett resultat. Resultat: Analysen resulterade i tre underrubriker: Information, Bemötande och Vårdmiljö, med uppdelning av positiva och negativa upplevelser. Många patienter var nöjda med vården, men hade låga förväntningar från början. Patienterna har förstående för personalens tuffa arbetsmiljö, men önskade att få bättre information om väntetid och undersökningar. De tyckte att väntetiden var för lång, och kände sig ofta ensamma och övergivna. Slutsats: Mycket behöver förändras för att patienterna ska få en mer positiv upplevelse av akuten. Detta arbeta kan hjälpa till att belysa vilka punkter som vården måste arbeta extra mycket med för att patienterna ska känna sig trygga, exempelvis bättre information om väntetider och ett bemötande där sjusköterskan ser hela patienten.

Faktorer som påverkar patienters upplevelse av omvårdnad under sin vistelse på akutmottagning. : - En litteraturstudie

Bakgrund: På en akutmottagning kommer patienter i olika tillstånd och behov. Det är sjuksköterskan som ofta gör de första bedömningarna och därför är det av stor vikt att bemötandet från sjuksköterskan är positivt för att skapa trygghet. Ökat patientflöde och långa väntetider är några faktorer som är påvisade att kunna påverka upplevelsen för patienterna av sin vistelse på akutmottagningen. Syfte: Syftet med litteraturöversikten var att beskriva faktorer som påverkar patienters upplevelse av omvårdnad under sin vistelse på akutmottagning. Metod: Studien genomfördes som en litteraturöversikt. Databaserna CINAHL och PubMed användes för att söka efter artiklar. Resultat: Sex underkategorier valdes ut: bemötande, delaktighet, information, väntetid, kommunikation och kontinuitet, sjuksköterskans kunskap och kompetens. Resultatet visade att många patienter ansåg att sjuksköterskan var skicklig i sina arbetsuppgifter och var nöjda med bemötandet från sjuksköterskan, men att långa väntetider och bristande information påverkade upplevelsen av omvårdnad. Det fanns en tydlig önskan över att få mer information om sin väntetid, behandling och undersökningar. Brister i detta, skapade en otrygghet och en känsla av vara bortglömd hos patienterna. Slutsats: Sjuksköterskor på en akutmottagning behöver besitta en stor kommunikationsförmåga. Detta för att kunna ge patienterna en så bra upplevelse som möjligt. Slutsatser av resultatet har påvisat att det krävs förbättring inom flera områden för att ge patienter en bättre upplevelse av omvårdnaden under sin vistelse på akutmottagningen.