Approved for public release; distribution in unlimited. / In the management of the U.S. Naval inventory, data quality is of critical importance. Errors in major inventory databases contribute to increased operational costs, reduced revenue, and loss of confidence in the reliability of the supply system. Maintaining error-free databases is not a realistic objective. Data-quality efforts must be prioritized to ensure that limited resources are allocated to achieve the maximum benefit. This thesis proposes a methodology to assist the Naval Inventory Control Point in the prioritization of its data-quality efforts. By linking data errors to Naval inventory performance metrics, statistical testing is used to identify errors that have the greatest adverse impact on inventory operations. By focusing remediation efforts on errors identified in this manner, the Navy can best use its limited resources devoted to improvement of data quality. Two inventory performance metrics are considered: Supply Material Availability (SMA), an established metric in Naval inventory management; and Backorder Persistence Metric (BPM), which is developed in the thesis. Backorder persistence measures the duration of time that the ratio of backorders to quarterly demand exceeds a threshold value. Both metrics can be used together to target remediation on reducing shortage costs and improving inventory system performance. / Lieutenant Commander, Supply Corps, United States Navy

Group Purchasing Organizations (GPOs) play a significant role in the healthcare industry. The presence of GPOs helps the healthcare centers to offload their responsibilities so that they can focus on more critical areas which require attention like providing quality care. This thesis involves the comparison of three models of procurement operations in terms of cost efficiency. This cost comparison model features a healthcare organization associated with a national GPO, a healthcare organization which procures by self sourcing (not associated with a GPO), and a hybrid procurement model involving a national GPO and a regional GPO. The comparison model highlighted the cost effectiveness of these three different ways of procurement, which threw significant light on the purchasing operations of healthcare organizations. In the second part of this research study, we formulated a method to measure the degree of access to innovative products across the above mentioned procurement models either involving on-contract (from a GPO) purchasing, or off-contract purchasing (from individual manufacturers not affiliated to GPO) or both. We also identified the metrics for innovation and measure the innovativeness of products. Based on the literature study, it was found that purchasing groups may also be an entry barrier to new suppliers (Zweig 1998), with big national GPOs dominating the market and dictating the pricing of commodities. The first hypothesis H1 of this research study was stated as "National GPOs (Group Purchasing Organizations) enable the healthcare establishments to lower the cost of medical services and operations." The second hypothesis H2 of this research study was acknowledged as "National GPOs a barrier to entry of Innovative product manufacturers in the healthcare industry." This thesis will identify the advantages and disadvantages of each type of procurement operation and address the economic issues which affect the relationship between a healthcare center and a GPO. The proposed research would indirectly help to identify whether cost savings are being shared by the links in the downstream supply chain and the savings are being percolated to the patients for the added welfare of the society. It will also identify the importance of innovative products in the society and will raise the bar of specialty treatments without compromising on the level of service being offered to the patients. This thesis will also highlight positive aspects of niche manufacturers of innovative products with smaller volumes which are currently marginalized in the market by the big national players. To the best of the author's knowledge, the research objective of measuring innovation of products has not been addressed yet in academic literature and will have the benefit of comparing three different purchasing models used in healthcare industry.

The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.

The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.

Open site measurement on the electromagnetic interference is the most direct and universally accepted standard approach for measuring radiated emissions from an equipment or the radiation susceptibility of a component or equipment. A site is qualified for testing EMI or not is decided by the antenna measurements. In this work, we use data from setups with di erent factors to find relations of measurement and the situation of antenna. A one change point model has been used to fit observed measurements and compare the di erences with two kinds of antenna (broadband antenna and dipole antenna). However, with only one change point model it may not give a suitable fit for all data sets in this work. Therefore, we have tried other models and applied them to the data. Furthermore, we try to set up another standard more strict than ¡Ó4dB based on statistical inference results in deciding whether a site is a better one with more precision in measuring EMI values. Finally, a program by Matlab with a complete analysis based on the procedure performed here is provided, so that it may be used as a standard tool for evaluating whether a site is with good measurement quality in practice.

In this paper we propose a generalized rank test based on discrete interval-censored failure time data to determine whether two lifetime populations come from the same distribution. It reduces to the Logrank test or Wilcoxon test when one has exact or right-censored data. Simulation shows that the proposed test performs pretty satisfactory. An example is presented to demonstrate how the proposed test can be applied in AIDS study.

The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.

The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.

No description available.

During the last decades, the power grid is getting rapidly digitalised in order to contribute to theestablishment of Smart Grids and evaluate efficiently the extracted bidirectional data from the powersystem infrastructure. This thesis focuses on the MV grid, since its design and operation have changedmainly because of distributed generation installations and the increased demand of information fromstakeholders. Thus, asset management constitutes a significant tool that can increase the reliability ofthe MV network’s operation and its level of control. Studies have shown that a maintenance planbased on condition monitoring of power system apparatuses would be more effective compared to theimplemented time-based scheduled maintenance.This project focuses on MV remotely controlled disconnectors since studies have shown that theirnumber of failures is double compared to manually operated ones. Since maneuverability andsecondary function are the causes of a major failure with the highest occurrence rate, motor currentmonitoring is studied in this thesis. Some devices that have the capability to monitor disconnectors’motor current, are presented. Additionally, the obtained max motor current measurements areevaluated through a parametric and a non-parametric statistical test. The main challenge of this thesisis to show whether the behaviour of motor current can be an indicator regarding to the disconnector’scondition status.Hence, the impact of different factors on the behaviour of motor current is investigated. It is concludedthat disconnectors without a failure during the studied period are more likely to have max motorcurrent measurements higher than 8A and especially in the interval [10-12]A. The difference in motorcurrent of disconnectors with a work order and without failure is more significant in 2015/2016. Itseems that under the aforementioned values of max motor current, a disconnector is more probable tohave the capability to operate properly. It is also concluded that in case of malfunction “Mellanläge”,the value of max motor current is lower than 8A with higher probability and it maybe indicates aproblem of the studied disconnector.Through the comparison in pairs, it could be concluded that the effect of the external environmentalconditions is not so high on the behaviour of disconnectors’ max motor current measurements. Incontrast, it seems that the implementation of a work order, the number of operations and if adisconnector is installed more northerly in Zone 3 play a more significant role on the behaviour of thisdisconnector’s max motor current measurements. Consequently, based on the aforementioned results itis shown that some of the investigated factors could constitute an indicator whether a disconnector ismore or less probable to have the capability to operate properly.Finally, it is calculated the reduction in the interruption cost that could be achieved in case ofimplementation of motor current monitoring on Vattenfall’s remotely controlled distributeddisconnectors. / Under de senaste årtiondena har kraftnät blivit snabbt digitaliserad För att bidra till upprättandet hosSmart Grids och effektivt utvärdera de extraherade dubbelriktade data från kraftsystemetsinfrastruktur. Denna exjobbsrapport fokuserar på MV-nätet, eftersom dess design och drift harförändrats främst på grund av distribuerade produktionsanläggningar och ökad efterfrågan påinformation från intressenter. Därför utgör ”asset management’’ ett viktigt verktyg som kan öka elnätstillförlitligheten och styrning. Studier har visat att elnäts underhåll baserad på tillståndsövervakningpå kraftsystemkomponenter skulle kunna vara effektivare jämfört med tidsbaserade schemalagdaunderhåll.Detta exjobb fokuserar på MV-fjärrstyrda frånskiljare eftersom studier har visat att deras felfrekvensär dubbelt högre jämfört med manuella. Eftersom problem i manövrerbarhet och sekundär funktionkan orsaka allvarliga fel med hög frekvens, har studien fokuserats på motorströmövervakningen idetta exjobb. Vissa produkter som har förmåga att övervaka frånskiljares motorström, presenteras.Dessutom utvärderas de maximala motorströmsmätningarna genom både parametriskt och ickeparametrisktstatistiskt test. Huvudutmaningen i denna avhandling är att utreda om motors strömmarkan vara en indikator för frånskiljares tillstånd.Olika faktorer hos motorströmmar har också undersökts. Det dras slutsatsen att frånskiljare utanmisslyckande manövern under den studerade perioden är mer benägna att ha maximalamotorströmmar högre än 8A och speciellt i intervallet [10-12] A. Skillnaden i motors strömmar hosfrånskiljare med arbetsorder och utan fel är mer signifikant under åren 2015/2016. Det verkar som attenligt ovan nämnda värden på max motorström, är en frånskiljare mer sannolikt att fungera korrekt.Det kommer också fram till att i händelse av "Mellanläge" är värdet av max motorströmmar lägre än8A med högre sannolikhet, detta kan kanske indikera ett problem hos frånskiljaren.Genom jämförelsen kan man dra slutsatsen att effekten av de yttre miljöförhållandena inte är så högpå maximala motorströmmar hos frånskiljare. Däremot verkar det som om genomförandet av enarbetsorder, antalet operationer och om en frånskiljare är installerad i zon 3 spelar en viktig roll föruppförandet av denna frånskiljares maximala motors strömmen. På grundval av det ovan nämndaresultatet framgår det att några av de undersökta faktorerna kan utgöra en indikator på att om enfrånskiljare är mer eller mindre sannolikt att ha förmågan att fungera korrekt.Slutligen visar beräkningar att minskningen av avbrottskostnaden kan uppnås vid genomförande avmotorströmövervakning på Vattenfalls fjärrstyrda distribuerade frånskiljare.