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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Tattle - "Here's How I See It" : Crowd-Sourced Monitoring and Estimation of Cellular Performance Through Local Area Measurement Exchange

Liang, Huiguang 01 May 2015 (has links)
The operating environment of cellular networks can be in a constant state of change due to variations and evolutions of technology, subscriber load, and physical infrastructure. One cellular operator, which we interviewed, described two key difficulties. Firstly, they are unable to monitor the performance of their network in a scalable and fine-grained manner. Secondly, they find difficulty in monitoring the service quality experienced by each user equipment (UE). Consequently, they are unable to effectively diagnose performance impairments on a per-UE basis. They currently expend considerable manual efforts to monitor their network through controlled, small-scale drive-testing. If this is not performed satisfactorily, they risk losing subscribers, and also possible penalties from regulators. In this dissertation, we propose Tattle1, a distributed, low-cost participatory sensing framework for the collection and processing of UE measurements. Tattle is designed to solve three problems, namely coverage monitoring (CM), service quality monitoring (QM) and, per-device service quality estimation and classification (QEC). In Tattle, co-located UEs exchange uncertain location information and measurements using local-area broadcasts. This preserves the context of co-location of these measurements. It allows us to develop U-CURE, as well as its delay-adjusted variant, to discard erroneously-localized samples, and reduce localization errors respectively. It allows operators to generate timely, high-resolution and accurate monitoring maps. Operators can then make informed, expedient network management decisions, such as adjusting base-station parameters, to making long-term infrastructure investment. We propose a comprehensive statistical framework that also allows an individual UE to estimate and classify its own network performance. In our approach, each UE monitors its recent measurements, together with those reported by co-located UEs. Then, through our framework, UEs can automatically determine if any observed impairment is endemic amongst other co-located devices. Subscribers that experience isolated impairments can then take limited remedy steps, such as rebooting their devices. We demonstrate Tattle's effectiveness by presenting key results, using up to millions of real-world measurements. These were collected systematically using current generations of commercial-off-the-shelf (COTS) mobile devices. For CM, we show that in urban built-up areas, GPS locations reported by UEs may have significant uncertainties and can sometimes be several kilometers away from their true locations. We describe how U-CURE can take into account reported location uncertainty and the knowledge of measurement co-location to remove erroneously-localized readings. This allows us to retain measurements with very high location accuracy, and in turn derive accurate, fine-grained coverage information. Operators can then react and respond to specific areas with coverage issues in a timely manner. Using our approach, we showcase high-resolution results of actual coverage conditions in selected areas of Singapore. For QM, we show that localization performance in COTS devices may exhibit non-negligible correlation with network round-trip delay. This can result in localization errors of up to 605.32m per 1,000ms of delay. Naïve approaches that blindly accepts measurements with their reported locations will therefore result in grossly mis-localized data points. This affects the fidelity of any geo-spatial monitoring information derived from these data sets. We demonstrate that using the popular localization approach of combining Global-Positioning System together with Network-Assisted Localization, may result in a median root-mean-square (rms) error increase of over 60%. This is in comparison to simply using the Global-Positioning System on its own. We propose a network-delay-adjusted variant of U-CURE, to cooperatively improve the localization performance of COTS devices. We show improvements of up to 70% in terms of median rms location errors, even while subjected to uncertain real-world network delay conditions, with just 3 participating UEs. This allows us to refine the purported locations of delay measurements, and as a result, derive accurate, fine-grained and actionable cellular quality information. Using this approach, we present accurate cellular network delay maps that are of much higher spatial-resolution, as compared to those naively derived using raw data. For QEC, we report on the characteristics of the delay performance of co-located devices subscribed to 2 particular cellular network operators in Singapore. We describe the results of applying our proposed approach to addressing the QEC problem, on real-world measurements of over 443,500 data points. We illustrate examples where “normal” and “abnormal” performances occur in real networks, and report instances where a device can experience complete outage, while none of its neighbors are affected. We give quantitative results on how well our algorithm can detect an “abnormal” time series, with increasing effectiveness as the number of co-located UEs increases. With just 3 UEs, we are able to achieve a median detection accuracy of just under 70%. With 7 UEs, we can achieve a median detection rate of just under 90%. 1 The meaning of Tattle, as a verb, is to gossip idly. By letting devices communicate their observations with one another, we explore the kinds of insights that can elicited based on this peer-to-peer exchange.
72

Benefits and Challenges with Global Sourcing : A study of Swedish companies

Johnsson, Christian, Morling, Felix January 2011 (has links)
Global sourcing is an important strategy for Swedish businesses since it is a mean to gain competitive advantage which is important on the global market Swedish businesses act on. Consequently it is interesting to investigate the importance of the perceived benefits and challenges with global sourcing since these factors affect the global sourcing decision. Thus, the purpose of this thesis is to investigate how Swedish large businesses perceive the benefits and challenges with global sourcing. To be able to fulfil the purpose primary data was used which was collected through an Internet based questionnaire where the respondents were asked to rank and rate the importance of the benefits and challenges with global sourcing. The data collected was in a quantifiable form and thus quantitative tools were used to analyse the collected data. The result of the study regarding the benefits was that price clearly was perceived as the most important benefit, while counter-trade obligations were seen as the least important benefit. Regarding the challenges, longer lead times and cultural issues were seen as the most challenging aspects, while customs regulations, tariffs and quotas and discrimination from the supplier were perceived as the least important challenges. However since too few responses of the questionnaire were obtained, these results is not generalizable on other Swedish businesses than those that are represented in the sample.
73

COARSE ORANGE POTTERY EXCHANGE IN SOUTHERN VERACRUZ: A COMPOSITIONAL PERSPECTIVE ON CENTRALIZED CRAFT PRODUCTION AND EXCHANGE IN THE CLASSIC PERIOD

Stoner, Wesley Durrell 01 January 2002 (has links)
This research seeks to elucidate the role of relatively large-scale ceramic productionindustries located at the Classic period center of Matacapan in the Sierra de los Tuxtlas, SouthernVeracruz, Mexico. Arnold et al. (1993) have suggested that the specialized production atComoapan, the largest production locality at Matacapan, was oriented toward supplying theregion with ceramics. This production locality overwhelmingly specialized in manufacturingone standardized ware, Coarse Orange, into necked and neckless jars, which are found in manyparts of the region.The compositional techniques of instrumental neutron activation analysis (INAA) andpetrography were employed to investigate the distribution of this ware. Control groups weresampled from known production loci at Matacapan. The data does reveal strong evidence thatCoarse Orange was traded from Matacapan to other sites in the Tuxtlas. Comoapan was themost likely producer for this trade. Equally as important, this research yielded several differentcompositional groups, which indicates sites that either did not interact with Matacapan to procurethis ware, or who produced their own varieties of Coarse Orange. While Matacapan seems tohave had economic influence over parts of the Tuxtlas, the distribution of non-Matacapancompositional groups is useful to delineate areas of the Tuxtlas who display minimal economicinteraction with this regional center.
74

Jakten på leveraged buyouts : en studie om deal sourcing på den svenska private equity marknaden

Teuchler, Alexandra, Barklöf, Anders January 2015 (has links)
Private equity bolag som skapar värde genom leveraged buyout har under de senaste åren fått ökad konkurrens inom den process vilken syftar till att finna attraktiva investeringar som kan generera avkastning enligt uppsatta avkastningskrav. Processen som karaktäriseras av informationsasymmetri och kallas för deal sourcing har därmed blivit ett svårare moment för dagens private equity bolag. Denna empiriska fallstudie undersöker hur svenska private equity bolag inom kategorin leveraged buyout i praktiken arbetar med deal sourcing och vilka drivkrafter som processen utformas efter i syfte att finna potentiella investeringar. Detta undersöks i ljuset av den akademiska forskning som tidigare gjorts på området. Studien utgår ifrån tio intervjuer med företagsrepresentanter vilka har insyn i och är delaktiga i processen med att finna bolag. Resultatet av studien visar att det studerade private equity bolaget följer samma deal sourcing process som beskrivs inom den akademiska litteraturen. Däremot kan det konstateras att terminologin skiljer sig mellan teorin och praktiken. Slutligen fann studien att värdegrund utgjorde en viktig drivkraft inom praktiken.
75

Lean logistic in a global environment how distance impacts lean inbound systems

Rapberger, Wolfgang January 2007 (has links)
Zugl.: Linz, Univ., Diss., 2007 / Hergestellt on demand
76

A Multi-factor Analysis of the Emergence of a Specialist-based Economy among the Phoenix Basin Hohokam

January 2013 (has links)
abstract: This project examines the social and economic factors that contributed to the development of a specialist-based economy among the Phoenix Basin Hohokam. In the Hohokam case, widespread dependence on the products of a few concentrated pottery producers developed in the absence of political centralization or hierarchical social arrangements. The factors that promoted intensified pottery production, therefore, are the keys to addressing how economic systems can expand in small-scale and middle-range societies. This dissertation constructs a multi-factor model that explores changes to the organization of decorated pottery production during a substantial portion of the pre-Classic period (AD 700 - AD 1020). The analysis is designed to examine simultaneously several variables that may have encouraged demand for ceramic vessels made by specialists. This study evaluates the role of four factors in the development of supply and demand for specialist produced red-on-buff pottery in Hohokam settlements. The factors include 1) agricultural intensification in the form of irrigation agriculture, 2) increases in population density, 3) ritual or social obligations that require the production of particular craft items, and 4) reduced transport costs. Supply and demand for specialist-produced pottery is estimated through a sourcing analysis of non-local pottery at 13 Phoenix Basin settlements. Through a series of statistical analyses, the study measures changes in the influence of each factor on demand for specialist-produced pottery through four temporal phases of the Hohokam pre-Classic period. The analysis results indicate that specialized red-on-buff production was initially spurred by demand for light-colored, shiny, decorated pottery, but then by comparative advantages to specialized production in particular areas of the Phoenix Basin. Specialists concentrated on the Snaketown canal system were able to generate light-colored, mica-dense wares that Phoenix Basin consumers desired while lowering transport costs in the distribution of red-on-buff pottery. The circulation of decorated wares was accompanied by the production of plainware pottery in other areas of the Phoenix Basin. Economic growth in the region was based on complementary and coordinated economic activities between the Salt and the Gila River valleys. / Dissertation/Thesis / Ph.D. Anthropology 2013
77

Reasons behind changing of sourcing strategies in software organizations : in India

Madala, Anvitha January 2017 (has links)
Context Global Software Development plays a crucial role in the growthof software organizations. It gives a way to global sourcing, which involvescongregation of knowledge forces from all over the world to work for thecompletion of software projects with benefits. Most of the organizations usesourcing strategies to connect with other organizations in order to form aprocess for the work. The document incorporates the types of organizationsinvolved in this practice. The sourcing specifications vary from those of thesoftware organizations when compared to the others. The sourcing strategieshave some criteria for their selection but the existing literature doesnot reflect the change of sourcing strategy. This forms a research gap whichfocuses on the reasons behind the change of sourcing strategies, particularlyin software organizations. When considering this, it varies from one locationto other. Taking this into account, India is chosen as it is one of thedeveloping countries globally.Objectives The main objective of this research is to investigate the reasonsbehind the change of sourcing strategies in the present software organizationswhich are located in India. This information should act as a primarysource of information which acts as a reference for selecting the sourcingstrategy based on reasons behind changing sourcing strategies.Methods In this research, mixed method approach is used. Through thisapproach both the criteria that are qualitative and quantitative data is obtained.At first for the literature review, the systematic mapping is usedto scrutinize the available information within the topic area. Secondly, thesurvey is done to gain the input at present from software organizations inIndia and finally, the interviews (India) are conducted to validate the resultsobtained from both the above mentioned methods. Further, for thesampling of the data from research, the convenience sampling is used. Theanalysis of qualitative data is done using the thematic analysis method andfor quantitative data, the descriptive statistics is used.Results The general reasons for the change of sourcing strategies implementedby software organizations are obtained from literature and also thestate of practice in India is retrieved through surveys. Also the final primarysource of information,a checklist of reasons behind the change of sourcingstrategies in India are documented.Conclusions The main objectives of the research are answered. The generalreasons are obtained by studying the state of art. State of practice also liststhe upcoming reasons caused due to recent changes in software organizationsin India. The primary source of information which are reasons behindthe change of sourcing strategies are mentioned with each particular sourcingstrategy segregating them in both technical and non-technical reasons inIndia. So that, it will act as a checklist for practitioners, apart from havingthe criteria of selection, this checklist based on reasons behind changing thesourcing strategies in India will help them to select the sourcing strategyand understand the reasons which will lead to run the process smoothly.
78

Evaluation of using NoSQL databases in an event sourcing system

Rothsberg, Johan January 2015 (has links)
An event store is a database for storing events in an event sourcing system. Instead of storing the current state, a very common way to persist data, an event sourcing system captures all changes to an application state as a sequence of events. Usually the event store is a relational database. Relational databases have several drawbacks and therefore NoSQL databases have been developed. The purpose of this thesis is to explore the possibility of using a NoSQL database in an event sourcing system. We will see how data is stored in an event store and then evaluate di↵erent solutions to find a suitable database. The graph database Neo4j was selected to be further investigated and a Neo4j event store has been implemented. At last the implemented solution is evaluated against the existing event store that uses a relational database. The conclusion of this thesis is that event store data could easily be modeled in Neo4j but some queries became complex to implement. The performance tests showed us that the implemented event store had poorer performance than the existing one using a relational database.
79

The impact of South African supermarkets on agricultural and industrial development in the Southern African Development Community

Emongor, Rosemary Akhungu 19 January 2009 (has links)
Supermarkets have become important in food retail in both developed and developing countries. Supermarkets in developed countries are expanding to developing countries such as Latin America and Asia resulting in transformation of the agro-food systems. As elsewhere in the world, supermarkets are also expanding rapidly in Africa. The growth and expansion of supermarkets is mainly spearheaded by South African supermarkets and has been facilitated by trade liberalization, increased economic growth, positive political changes, regional integration arrangements, increased urbanisation, increased per capita income and middle class population groups and liberalization of foreign direct investment. The increased foreign direct investment (FDI) by South African supermarkets into SADC and the rest of Africa may be impacting on firms, households and the economy in the host nations in various ways. As much as the FDI by South African firms bring the much-needed capital for development, the impact of South Africa supermarkets in SADC and the rest of Africa is least understood. The impact of the expansion of South African supermarkets in the retail sector in other African countries has not been elucidated. Therefore, the objective of this study was to determine the impact of supermarkets on agricultural and industrial (mainly the food processing and manufacturing sector) development in SADC by examining their sourcing and procurement practices. From the identified gaps in literature the study attempts to answer the following questions: what is the extent of growth and expansion of South African supermarkets in case study countries; what are the nature of sourcing and procurement practices and the factors influencing the choice of procurement systems; what are the impacts of these sourcing and procurement practices on farmers and food processors in case-study countries and do farmers gain by participating in the supermarkets FFV supply chain in case-study countries. A case study of three countries (Botswana, Namibia and Zambia) and two supply chains were studied. The study used qualitative and quantitative methods in collecting data in order to elucidate the impacts of these supermarkets on agricultural and industrial (food processing) development in the case study countries. A survey of South African and local chain supermarkets, local shops, food processors, small-scale farmers supplying fresh fruit and vegetables (FFV) to chain supermarkets and the traditional FFV markets was undertaken in the case-study countries in 2004, 2005 and 2007 using questionnaires and checklists. The survey data were augmented with key informant and focus group discussions and secondary data. The analytical methods used included descriptive analysis, non-parametric statistics and a two-step treatment regression analysis model. The conceptual framework for analysing the sourcing/procurement practices of supermarkets and a model to show how impacts in host countries could occur as a result of sourcing decisions were developed and used in the study. The results of the survey of products sold in supermarkets and local shops showed that 80% of all processed food products are sourced from South Africa. About 100% of temperate fruit and 70-100% tropical fruit are sourced from South Africa in the casestudy countries. About 80% of fresh vegetables are sourced from farmers in Zambia and about 80 % are sourced from South Africa for Botswana and Namibia. The results also revealed that supermarkets used a mixture of procurement systems for FFV and processed food products. These systems included use of specialised sourcing and procurement companies; direct delivery of FFV to individual supermarket stores; specialised FFV wholesalers; distribution centres; outsourcing. Using the structured questionnaire supermarket managers were asked the criteria used in sourcing the selected products. The results of the parametric analysis of the responses showed that price, volume, quality and trust were the most important attributes considered respectively. In order to estimate the impact of supermarkets on farmers a household survey was carried out using a structured questionnaire. There were noticeable differences in resources between farmers who supply to the supermarkets and those who supply to the traditional markets. Factors that influence small-scale farmers’ participation in the supermarkets supply chain were identified from the results of the estimated probit model. The results of the two-step treatment regression model showed that participation in the supermarkets channel had a positive impact on small-scale farmers’ income. Mean comparison of income between the two groups of farmers showed that farmers who supplied fresh vegetables to chain supermarkets had a significantly higher income compared to those who supplied to traditional markets in Zambia. This finding confirms hypothesis 2 of the study. The study did not explore causality due to insufficient data on lagged assets. Impacts on the food-processing sector were deduced by carrying out a survey of food processing firms in case-study countries. The goal was to determine the type of firms that access supermarkets supply chain for selected products and determine other channels used for marketing of the products. About 75% of firms started their operations in the 1990s. This period also coincided with rapid supermarket expansion in case-study countries. A symbiotic relationship exists between supermarkets and large processing firms in the case-study countries. There was no evidence to show that supermarkets have caused firms to increase in size or that supermarkets prevented entry of agro-processors in the food processing industry. Small-scale processing firms do not access supermarket supply chains in case-study countries and sell their products through the traditional channels such as small shops and wholesales. Various constraints still prohibit smallscale firms from accessing supermarkets such as lack of capital and lack of finances. From the results of the models and focus group discussions the study concluded that small-scale farmers who meet supermarkets sourcing/procurement requirements were able to access the FFV supply chain of the South African chain supermarkets. Those who did not meet the supermarket requirements who are the majority small-scale farmers and food processors were excluded. Those small-scale farmers who were able to supply to supermarkets earned significantly higher income compared to those who supply to the traditional markets. The study also concluded that membership in a farmers organization does not increase the chances of a farmers accessing and supplying to supermarkets. There is need to re-evaluate the farmer organizations that are being formed to ensure that the organizations assist farmers in accessing supermarkets FFV supply chain and marketing of produce in general. The study also concluded that the traditional markets are still important in case-study countries. These markets need to be improved and developed as small-scale farmers and food processors easily assess them. The study recommended that a holistic analysis of supermarket impacts in the region using general equilibrium type of models is needed, ways to ensure small-scale farmers and processors participation in supermarket FFV supply chain should be determined and more research on the practices of supermarkets as oligopsonists in the region should be carried out. The study was able to document the extent of growth and expansion of supermarkets in case-study countries and as such contributed to literature by describing the sourcing and procurement practices and factors that influence supermarket sourcing and procurement decisions in case-study countries, the study contributed to literature by identifying the type of small-scale farmers who access chain supermarkets in case-study countries, the study contributed by identifying the factors that influence farmers decisions to supply FFV markets and the study showed that supermarkets involvement in the FFV and dairy supply chains in case-study countries had a positive impact in these sectors. / Thesis (PhD)--University of Pretoria, 2009. / Agricultural Economics, Extension and Rural Development / unrestricted
80

Podpora lokálních dodavatelů ze strany retailových řetězců v ČR / Local producers support on Czech retail market

Stara, Jiří January 2011 (has links)
The thesis was suggested and assigned by Tesco Stores CR. The idea behind is to find out whether supporting local producers can bring a competitive advantage to an involved retailer on the Czech retail market. It is focused primarily on fresh food categories which seem to be the most suitable for local sourcing prefernce. The thesis also considers the relationship between quality-origin-customer expectation. The practical part includes two researches-one studies marketing tools used by retailers present on Czech market in order to promote local producers. The other one provides Czech food producers' opinion on retailers controlling Czech retail market.

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