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A search for hep neutrinos with the Sudbury Neutrino ObservatoryHoward, Christopher William 11 1900 (has links)
This thesis focuses on the search for neutrinos from the solar hep reaction using the combined three phases of the Sudbury Neutrino Observatory (SNO) data. The data were taken over the years 19992006, totalling 1,083 days of live neutrino time.
The previous published SNO hep neutrino search was completed in 2001 and only included the first phase of data taking. That hep search used an event counting approach in one energy bin with no energy spectral information included. This thesis will use a spectral analysis approach.
The hep neutrino search will be a Bayesian analysis using Markov Chain Monte Carlo (MCMC), and a Metropolis-Hastings algorithm to sample the likelihood space. The method allows us to determine the best fit values for the parameters. This signal extraction will measure the 8B flux, the atmospheric neutrino background rate in the SNO detector, and the hep flux.
This thesis describes the tests used to verify the MCMC algorithm and signal extraction. It defines the systematic uncertainties and how they were accounted for in the fit. It also shows the correlations between all of the parameters and the effect of each systematic uncertainty on the result.
The three phase hep signal extraction was completed using only 1/3 of the
full data set. With these lowered statistics, this analysis was able to place an
upper limit on the hep flux of 4.2 10^4 cm2 s1 with a 90% confidence limit.
It was able to measure a hep flux of (2.40(+1.19)(-1.60))10^4 cm2 s1. These numbers can be compared with the previous SNO upper limit of 2.310^4 cm2 s1 with a 90% confidence limit, and the standard solar model prediction of (7.970 1.236) 10^3 cm2 s1.
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Bethe Ansatz and Open Spin-1/2 XXZ Quantum Spin ChainMurgan, Rajan 12 April 2008 (has links)
The open spin-1/2 XXZ quantum spin chain with general integrable boundary terms is a fundamental integrable model. Finding a Bethe Ansatz solution for this model has been a subject of intensive research for many years. Such solutions for other simpler spin chain models have been shown to be essential for calculating various physical quantities, e.g., spectrum, scattering amplitudes, finite size corrections, anomalous dimensions of certain field operators in gauge field theories, etc. The first part of this dissertation focuses on Bethe Ansatz solutions for open spin chains with nondiagonal boundary terms. We present such solutions for some special cases where the Hamiltonians contain two free boundary parameters. The functional relation approach is utilized to solve the models at roots of unity, i.e., for bulk anisotropy values eta = i pi/(p+1) where p is a positive integer. This approach is then used to solve open spin chain with the most general integrable boundary terms with six boundary parameters, also at roots of unity, with no constraint among the boundary parameters. The second part of the dissertation is entirely on applications of the newly obtained Bethe Ansatz solutions. We first analyze the ground state and compute the boundary energy (order 1 correction) for all the cases mentioned above. We extend the analysis to study certain excited states for the two-parameter case. We investigate low-lying excited states with one hole and compute the corresponding Casimir energy (order 1/N correction) and conformal dimensions for these states. These results are later generalized to many-hole states. Finally, we compute the boundary S-matrix for one-hole excitations and show that the scattering amplitudes found correspond to the well known results of Ghoshal and Zamolodchikov for the boundary sine-Gordon model provided certain identifications between the lattice parameters (from the spin chain Hamiltonian) and infrared (IR) parameters (from the boundary sine-Gordon S-matrix) are made.
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Characterization of glutamine synthetase from the marine diatom Skeletonema costatum /Robertson, Deborah L. January 1997 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Molecular Genetics and Cell Biology, June 1997. / Includes bibliographical references. Also available on the Internet.
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Flödesekonomins dimensioner : supply chain managementBroberg, Elias, Wallin, Mattias January 2008 (has links)
It is of increasing importance to in the most effective possible way, manage and control all the transactions of raw materials, products and information that are exchanged between an organization and all its operators. These flows and the need for strategy and managing the processes of planning, implementing and control of the supply chain, has given name to the concept supply chain management. Supply chain management involves all movement and storage of raw material, and all the processes that is needed to manufacture a product from origin to consumption. Globalization, technology and increasing time and quality-based competition are all driving forces behind the concept and reasons for an increasing interest in supply chain management. The purpose of this essay is to by using a qualitative case study examine which decisive success factors that can be identified for effective supply chain management. We have compiled different theories on the subject to use for analyzing a case study Li & Fung, who is a successful supply chain management company. We intend to give a detailed description of this complex concept and identify decisive success factors for effective supply chain management. The study shows two prominent aspects for effective supply chain management; (1) Leadership and (2) control of the supply chain.
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Exploratory Investigation of Sales Forecasting Process and Sales Forecasting System : Case Study of Three CompaniesLaxmidhar, Mohammad, Sarang, Dnyanesh January 2007 (has links)
The future has always caught the attention of the human being. The thirst of exploring the future and to know the unknown has driven the human being toward innovativeness. Companies are expanding their operations worldwide since the past few decades. Profit growth coupled with an effective strategy has become the primary need of global companies. Research in this area has given rise to optimization of the supply chain for higher profitability. Considering the overall strategy the company needs to plan production well in advance. The operational planning comes in picture at this moment. In order to reduce excessive inventory at each stage of the production; one should know the demand of the next stage and preferably the end customer demand. The process of sales forecasting is undertaken to predict demand at different stages. It is a complex managerial function and hence needed to be undertaken by a scientific way. The sales forecasting the function includes process of forecasting, administration, hardware, software, users and developers of forecast. Historically sales forecasting has been considered as a side activity by most of the companies. Sales forecasting has not been considered as an important function of marketing and finance. Very few companies have seen sales forecasting by a scientific management point of view. Less research has been reported in sales forecasting in comparison to other managerial functions. Planning based on sales forecasting; may be part of a selected strategy for growth and profitability. These facts have attracted us to study sales forecasting as a managerial function. The purpose of this study is to describe and analyze the sales forecasting process, sales forecasting system, sales forecasting methods and techniques. Further proposing possibilities of improvements in existing forecasting process is also purpose of this study. We have selected three manufacturing companies for this study based on purposive sampling. Considering research interest in phenomenon study; we have selected a qualitative research strategy for this study. We have selected a case study method for our research as it is the most appropriate tool to study the relation between theory and phenomenon. For this research, we have collected the data by semistructured interviews based on a pre formed questionnaire. The questionnaire has been prepared with respect to our research purpose and open ended questions were used to gather extensive data. The data gathered during interviews, have been analyzed by the use of ‘Flow model’ suggested by Miles and Huberman (1994). Results from this study shows that there is a need to see ‘sales forecasting’ as a management function rather than a computer activity. To achieve the best information integration throughout the supply chain, increased information visibility is needed. To achieve accuracy in both forecasting and planning; collaborative forecasting may be used. Forecasting software needs to have a suite of methods towards product specific forecasting. The need of customized softwares has also been indicated by this study. The need to measure performance of forecasting by means of accuracy, cost and customer relationship has been concluded.
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Applications of the Wormlike Chain Model in Polymer Physics: Self-consistent Field TheoryJiang, Ying January 2013 (has links)
The self-consistent field theory (SCFT) has reveived a great success in prediction of the physical properties of a variety of polymeric systems in the recent two decades. However, the traditional SCFT is based on the Gaussian chain model, completely neglecting the chain rigidity effects, which is ascribed to one of the intrinsic properties of polymer chains. This thesis concentrates on the development of SCFT in the framework of the wormlike chain model and studies the influence of the chain rigidity on the chain configuration which directly determines properties of polymer materials in the mesoscale. Firstly, considering Onsager-type, orientational-dependent repulsive interactions, we study a model for the isotropic-nematic interface in liquid-crystals. Through adjusting the ratio of total contour length L to the persistence length lambda, we consider systems consisting of molecules with various degrees of flexibility: from rods to flexible chains. Physical properties such as the surface tension, interfacial width and density- and order-parameter profiles were numerically calculated as functions of the flexibility L/lambda and tilt angle, which is defined as the angle between the interfacial normal and the nematic director. Secondly, We examine the influence of persistency on the phase diagram of AB diblock copolymers and the properties of the phase transition as a function of volume fraction, Flory-Huggins parameter and chain rigidity, covering a broad regime spanning from Gaussian chains to rigid rodlike chains. On one hand, we demonstrate that results from a Gaussian-weight based theory can be recovered in the long-chain limit, and on the other hand, we display that significant revisions to the phase diagram, due to the persistency effects, exist for shorter chains. To achieve this, an efficient numerical scheme is designed for implementing the calculations of the wormlike-chain SCFT in a full six-dimensional space.
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Ett reservdelsflödeEn OrganisationskedjaFlera Synsätt : -En fallstudie om tvärfunktionellt samarbete på Atlas Copco DrillsFolkesson, Cecilia, Hiltunen, Henrik January 2010 (has links)
I denna undersökning studeras ett reservdelsflöde inom eftermarknad ur ett organisatorisktperspektiv. Reservdelen glidskenan på Atlas Copcos borriggar fungerar som fallstudieobjekt. Glidskenan är en tunn stålprofil, som mäter mellan två och åtta meter och skyddar matarbalkarna på ovan- och underjordsborriggar mot slitage. Vår uppdragsgivare Atlas Copcos Shared Distributionscenter (i fortsättningen DC) upplever problem i flödet av glidskenor. Glidskenan är skrymmande och svår att hantera, förpacka och transportera och flödet flyter inte effektivt. De upplevda problemen har varit kända i över 12 år och förbättringsansatser har runnit ut i sanden. Genom kartläggning av hur flödet flyter idag och hur organisationen runt flödet agerar har tre teman presenterats och analyserats. Dessa tre teman förklarar de bakomliggande organisatoriska aspekterna som påverkar glidskenans flöde och varför de upplevda problemen inte blir åtgärdade. Studien lyfter fram vikten av samarbete mellan de olika organisatoriska funktionerna och individerna i organisationen. Om samarbetet dem emellan fungerar kan synergieffekter erhållas, men ett bristande samarbete kan också hämma organisationens potential. Det första temat behandlar att kunskap finns inom organisationen, men att den inte sprids mellan medarbetarna. Med utgångspunkt i studiens andra tema konstaterar vi att medarbetarnas olika syn på glidskenan utgör en barriär för kunskapsspridning. Olika syn hämmar även medarbetarnas engagemang och intresse för att hitta förbättringar inom glidskenans flöde. I studiens tredje tema, avstånd, ser vi att organisationens fysiska men framförallt mentala avstånd hindrar organisationsmedlemmarna att känna en vi-samhet. Utan denna vi-samhet finns inga incitament till samarbete för att effektivisera glidskenans flöde. / In this research a spare part flow within aftermarket has been studied through an organizational perspective. The slide-bar is a spare part in Atlas Copco Rock Drills assortment and forms a case study for our research. The slide bar is a thin steel profile which measures between two and eight centimetres. They are placed on the feeders of surface- and underground drilling rigs as a protection from wear and tear. Atlas Copco Shared Distribution Center (DC) has given us a case as a background for our research. The slide bars are bulky to handle, wrap and transport and for DC the flow appears to be ineffective and expensive. DC are experiencing problems within the material flow of slide bars and is puzzled why no improvement has been done, although the problems has been known to DC for over twelve years. Projects to improve the flow has been initiated but gone down the drains.
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Integrated Tactical-Operational Supply Chain Planning with Stochastic Dynamic ConsiderationsFakharzadeh-Naeini, Hossein 24 November 2011 (has links)
Integrated robust planning systems that cover all levels of SC hierarchy have become increasingly important. Strategic, tactical, and operational SC plans should not be generated in isolation to avoid infeasible and conflicting decisions. On the other hand, enterprise planning systems contain over millions of records that are processed in each planning iteration. In such enterprises, the ability to generate robust plans is vital to their success because such plans can save the enterprise resources that may otherwise have to be reserved for likely SC plan changes. A robust SC plan is valid in all circumstances and does not need many corrections in the case of interruption, error, or disturbance. Such a reliable plan is proactive as well as reactive. Proactivity can be achieved by forecasting the future events and taking them into account in planning. Reactivity is a matter of agility, the capability of keeping track of system behaviour and capturing alarming signals from its environment, and the ability to respond quickly to the occurrence of an unforeseen event. Modeling such a system behaviour and providing solutions after such an event is extremely important for a SC.
This study focuses on integrated supply chain planning with stochastic dynamic considerations. An integrated tactical-operational model is developed and then segregated into two sub-models which are solved iteratively. A SC is a stochastic dynamic system whose state changes over time often in an unpredictable manner. As a result, the customer demand is treated as an uncertain parameter and is handled by exploiting scenario-based stochastic programming. The increase in the number of scenarios makes it difficult to obtain quick and good solutions. As such, a Branch and Fix algorithm is developed to segregate the stochastic model into isolated islands so as to make the computationally intractable problem solvable. However not all the practitioners, planners, and managers are risk neutral. Some of them may be concerned about the risky extreme scenarios. In view of this, the robust optimization approach is also adopted in this thesis. Both the solution robustness and model robustness are taken into account in the tactical model. Futhermore, the dynamic behaviour of a SC system is handled with the concept of Model Predictive Control (MPC).
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Measuring the Delivery Precision at Holmen PaperBartoll, Christian, Wibaeus, Johan January 2012 (has links)
This thesis aims to evaluate measurement techniques for delivery precision at Holmen Paper (HP). Delivery precision is an important KPI for a business, because it gives an indication of how well the company’s supply chain is performing. At HP, the Operation and Logistics division, wants to use the result to assess that if they are doing a good job planning HP’s production and transportation. The purpose of the thesis: “The purpose of the thesis is to determine how the KPI delivery precision ought to be measured for various order types in Holmen Paper’s supply chain.” A great deal of literature was initially reviewed on the subject of delivery precision, and different sources suggested alternative ways in which it may be determined. To understand the logistics and information flow, two flow-charts where constructed. This was done in order to obtain a holistic overview of HP’s order-delivery process, and furthermore, to see where the required data could be retrieved from the system. After evaluating the supply chain, it was concluded that the SCOR models’ pre-defined Key Performance Indicator Perfect Order Fulfillment (POF) and Perfect Order Index (POI), were the best way to measure the delivery precision. Both theories are well known in the logistics sector and both are built upon lower level metrics. The metrics measure if an order is delivered satisfactorily to a customer, according the parameters of time, quantity, quality and documentation. The thesis, however, rejected the parameter of documentation in dialogue with HP (and because the parameter has little to do with the operators work at Operation and Logistics). Data was collected from HP’s database in an attempt to measure the delivery precision according to both the theories. However, it was concluded that the calculated value was unreliable. This was mainly due to fact that the data required did not exist, and the data that did exist was not reliable. The data was seen as unreliable because there was no information of when the data was collected along the supply chain. Therefore, the thesis presents a model that will help HP implement the KPI delivery precision in the future. At the completion of the study, it was concluded that HP, initially, needs to implement a system to save data regarding the reason and source of order modifications. Additionally, it is suggested that HP should try to measure the delivery precision as close to the customer as possible. Currently, the data required to do this does not exist. To obtain this data, HP needs to implement some sort of receipt when the customer receives the goods.
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Managing Inventory, Transportation and Location in a Supply ChainAbouee Mehrizi, Hossein 05 January 2012 (has links)
We consider three problems on inventory, transportation and location in a supply chain. In Chapter 2, we study Multilevel Rationing (MR) and Strict Priority (SP) stock allocation policies for a centralized single product multi-class M/G/1 make-to-stock queueing systems. To obtain the total cost of the system under these policies, we introduce a new method called “customer composition”. Using this method, we focus on the proportion of customers of each class out of the total number of customers in the queue since the number of customers in M/G/1 queues is invariant for any non-idling and non-anticipating policy. We consider a series of two-priority M/G/1 queues with an exceptional service time in each busy period to characterize the customer composition. We derive closed form expressions for the costs of SP and MR policies using these results.
In Chapter 3, we consider a two-echelon inventory system with a congested centralized production facility and several Distribution Centers (DCs). We assume that the production and transportation times are stochastic that are generally distributed, and customers arrive to each DC according to an independent Poisson process. Inventory at DCs is managed using the one-for-one replenishment policy. We use the customer composition approach to characterize the total inventory carrying and backlog costs of the system under the FCFS, SP and MR allocation policies at the warehouse. For the special case of exponentially distributed production and transportation times, we use the unit-flow method and derive closed form expressions for the optimal cost and base-stock level of the DCs. We numerically demonstrate that prioritization using either the SP or the MR policy could be very beneficial in comparison with the FCFS policy.
In Chapter 4, we study a two-echelon supply chain with a set of suppliers, a set of retailers and a set of capacitated cross-docks which are to be established. The demand of the retailers could be satisfied from the suppliers through the cross-docks. The objective is to determine the number and location of cross-docks, the assignment of retailers to suppliers so that the total cost of pipeline and retailers’ inventory, transportation, and facility location is minimized. We formulate the problem as a non-linear mixed integer programming and derive several structural results for special cases of the problem. To solve the general problem, we show that it can be written as a cutting stock problem and develop a column generation algorithm to solve it. We investigate the efficiency of the proposed algorithm numerically.
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