"October 2001." Bibliography: leaves 99-103. Establishes several sets of conditioning relating to the variant optimal deign of linear consecutive-k-out-of-n systems and includes a review of existing research in the theory of variant optimal design of linear consecutive-k-out-of-n systems.

The ability to attract and retain customers through providing excellent service quality is a necessity for any business in every field. However, before a firm can expect to consistently provide high quality service, it must first know how to measure and identify areas of needed improvement. While service quality research has been conducted in most of the major sectors of the economy, the residential real estate brokerage industry is only beginning to incorporate existing knowledge of service quality management. This is especially disconcerting given that real estate is such a large part of local and national economies around the world. The purpose of this thesis is to identify the best instrument that can be used to measure service quality in the residential real estate brokerage industry. The findings reveal that the reliability, responsiveness and empathy dimensions significantly lead to increases in the overall evaluation of service the firm provides. The empathy dimension also significantly causes homebuyers to recommend the firm to others. Additionally, empathy significantly causes the client to use the firm again. Finally, as hypothesized, overall satisfaction leads to both repeat uses of the firm and recommending the firm to a friend. / Doctor of Philosophy (PhD)

Security and reliability in processor based systems are concerns requiring adroit solutions. Security is often compromised by code injection attacks, jeopardizing even ???trusted software???. Reliability is of concern, where unintended code is executed in modern processors with ever smaller feature sizes and low voltage swings causing bit flips. Countermeasures by software-only approaches increase code size and therefore significantly reduce performance. Hardware assisted approaches use additional hardware monitors and thus incur considerably high hardware cost and have scalability problems. Considering reliability and security issues during the design of an embedded system has its advantages as this overcomes the limitations of existing solutions. The research work presented in this thesis combines two elements: one, defining a hardware software design framework for reliability and security monitoring at the granularity of micro-instructions, and two, applying this framework for real world problems. At a given time, a processor executes only a few instructions and large part of the processor is idle. Utilizing these idling hardware components by sharing them with the monitoring hardware, to perform security and reliability monitoring reduces the impact of the monitors on hardware cost. Using micro-instruction routines within the machine instructions, allows us to share most of the monitoring hardware. Therefore, our technique requires little hardware overhead in comparison to having additional hardware blocks outside the processor. This reduction in overhead is due to maximal sharing of hardware resources of the processor. Our framework is superior to software-only techniques as the monitoring routines are formed with micro-instructions and therefore reduces code size and execution time overheads, since they occur in parallel with machine instructions. This dissertation makes four significant contributions to the field of security and reliability on embedded processor research and they are: (i) proposed a security and reliability framework for embedded processors that could be included into its design phase; (ii) shown that inline (machine instruction level) monitoring will detect common security attacks (four inline monitors against common attacks cost 9.21% area and 0.67% performance, as opposed to previous work where an external monitor with two monitoring modules costs 15% area overhead); (iii) illustrated that basic block check-summing for code integrity is much simpler and efficient than currently proposed integrity violation detectors which address code injection attacks (this costs 5.03% area increase and 3.67% performance penalty with a single level control flow checking, as opposed to previous work where the area overhead is 5.59%, which needed three control flow levels of integrity checking); and (iv) shown that hardware assisted control flow checking implemented during the design of a processor is much cheaper and effective than software only approaches (this approach costs 0.24-1.47% performance and 3.59% area overheads, as opposed to previous work that costs 53.5-99.5% performance).

The primary objective of the research reported in this thesis was the improvement of safety in helicopters by identifying and, where necessary, developing vibration analysis techniques for the detection and diagnosis of safety critical faults in helicopter transmission systems. A review and, where necessary, expansion of past research is made into (a) the mechanisms involved in the production of vibrations in mechanical systems, (b) the failure modes experienced in geared transmission systems, (c) which failure modes are critical to the safety of helicopters, (d) how the safety critical failure modes affect the vibration signature, and e) the vibration analysis techniques currently used to detect safety critical failures. The effectiveness of the currently available vibration analysis techniques is investigated using in-flight vibration data from Royal Australian Navy helicopters and seeded fault data from a purpose built spur gear test rig. Detailed analysis of techniques for synchronous signal averaging of gear vibration data is undertaken, which includes the development of new methods of modelling and quantifying the effects of synchronous averaging on non-synchronous vibration. A study of digital resampling techniques is also made, including the development of two new methods which provide greater accuracy and/or efficiency (in computation) over previous methods. A new approach to fault diagnosis is proposed based on time-frequency signal analysis techniques. It is shown that these methods can provide significant improvement in diagnostic capabilities over existing vibration analysis techniques. Some limitations of general time-frequency analysis techniques are identified and a new technique is developed which overcomes these limitations. It is shown that the new technique provides a significant improvement in the concentration of energy about the instantaneous frequency of the individual components in the vibration signal, which allows the tracking of small short term amplitude and frequency modulations with a high degree of accuracy. The new technique has the capability of 'zooming' in on features which may span only a small frequency range, providing an enhanced visual representation of the underlying structure of the signal.

Melbourne, the capital of Victoria Australia leads the world in having the highest quality drinking water. The Victorian State Government has set targets for reducing per capita water consumption by 15%, 25% and 30% by 2010, 2015 and 2020 respectively and has announced stringent water restrictions to curtail water demand. In this resource constraint environment it is opportune to look for alternative sources of water to supplement Melbourne's traditional water supply. In Melbourne, legislation has been changed to make it possible to use rainwater harvested from domestic tanks for non potable purposes. The annual rainfall in Melbourne's metropolitan area varies from 450mm in the West to 850mm in the East to over 1000mm in the North East mountain ranges. The objectives of the current study are to develop a methodology to estimate the optimal size of the rainwater tank at a particular location considering the local rainfall, roof area, demand for water and the reliability of supply (supply security) required; to quantify the rainwater volume that could be harvested at site using domestic rainwater tanks to minimise pressure on the potable water supply secured from traditional catchment sources until the desalination plant is commissioned in 2013; to analyse the efficacy of rainwater tanks to reduce the stormwater runoff and improve the quality of the stormwater that will otherwise flow into urban drains and to estimate the cost effectiveness ratio and payback period of inst alling rainwater tanks. A simple water balance model was developed to calculate the tank size based on daily rainfall, roof area and the expected demand. The concept of 'reliability' was introduced to measure supply security. Rainfall data from 20 rainfall stations scattered around Melbourne were used to determine the variation in the rainwater tank size dependent on the above stated parameters. It was observed that to achieve the same supply reliability (90%) and to meet a specific demand (toilet and garden use), the tank size required in the western side of Melbourne is as high as 7 times as that required in the north-east side. As a result, the

This thesis contributes toward the design of a reliable and energy-efficient transport system for Wireless Sensor Networks. Wireless Sensor Networks have emerged as a vital new area in networking research. In many Wireless Sensor Network systems, a common task of sensor nodes is to sense the environment and send the sensed data to a sink node. Thus, the effectiveness of a Wireless Sensor Network depends on how reliably the sensor nodes can deliver their sensed data to the sink. However, the sensor nodes are susceptible to loss for various reasons when there are dynamics in wireless transmission medium, environmental interference, battery depletion, or accidentally damage, etc. Therefore, assuring reliable data delivery between the sensor nodes and the sink in Wireless Sensor Networks is a challenging task. The primary contributions of this thesis include four parts. First, we design, implement, and evaluate a cross-layer communication protocol for reliable data transfer for data streaming applications in Wireless Sensor Networks. We employ reliable algorithms in each layer of the communication stack. At the MAC layer, a CSMA MAC protocol with an explicit hop-by-hop Acknowledgment loss recovery is employed. To ensure the end-to-end reliability, the maximum number of retransmissions are estimated and used at each sensor node. At the transport layer, an end-to-end Negative Acknowledgment with an aggregated positive Acknowledgment mechanism is used. By inspecting the sequence numbers on the packets, the sink can detect which packets were lost. In addition, to increase the robustness of the system, a watchdog process is implemented at both base station and sensor nodes, which enable them to power cycle when an unexpected fault occurs. We present extensive evaluations, including theoretical analysis, simulations, and experiments in the field based on Fleck-3 platform and the TinyOS operating system. The designed network system has been working in the field for over a year. The results show that our system is a promising solution to a sustainable irrigation system. Second, we present the design of a policy-based Sensor Reliability Management framework for Wireless Sensor Networks called SRM. SRM is based on hierarchical management architecture and on the policy-based network management paradigm. SRM allows the network administrators to interact with the Wireless Sensor Network via the management policies. SRM also provides a self-control capability to the network. This thesis restricts SRM to reliability management, but the same framework is also applicable for other management services by providing the management policies. Our experimental results show that SRM can offer sufficient reliability to the application users while reducing energy consumption by more than 50% compared to other approaches. Third, we propose an Energy-efficient and Reliable Transport Protocol called ERTP, which is designed for data streaming applications in Wireless Sensor Networks. ERTP is an adaptive transport protocol based on statistical reliability that ensures the number of data packets delivered to the sink exceeds the defined threshold while reducing the energy consumption. Using a statistical reliability metric when designing a reliable transport protocol guarantees the delivery of adequate information to the users, and reduces energy consumption when compared to the absolute reliability. ERTP uses hop-by-hop Implicit Acknowledgment with a dynamically updated retransmission timeout for packet loss recovery. In multihop wireless networks, the transmitter can overhear a forwarding transmission and interpret it as an Implicit Acknowledgment. By combining the statistical reliability and the hop-by-hop Implicit Acknowledgment loss recovery, ERTP can offer sufficient reliability to the application users with minimal energy expense. Our extensive simulations and experimental evaluations show that ERTP can reduce energy consumption by more than 45% when compared to the state-of- the-art protocol. Consequently, sensor nodes are more energy-efficient and the lifespan of the unattended Wireless Sensor Network is increased. In Wireless Sensor Networks, sensor node failures can create network partitions or coverage loss which can not be solved by providing reliability at higher layers of the protocol stack. In the final part of this thesis, we investigate the problem of maintaining the network connectivity and coverage when the sensor nodes are failed. We consider a hybrid Wireless Sensor Network where a subset of the nodes has the ability to move at a high energy expense. When a node has low remaining energy (dying node) but it is a critical node which constitutes the network such as a cluster head, it will seek a replacement. If a redundant node is located in the transmission range of the dying node and can fulfill the network connectivity and coverage requirement, it can be used for substitution. Otherwise, a protocol should be in place to relocate the redundant sensor node for replacement. We propose a distributed protocol for Mobile Sensor Relocation problem called Moser. Moser works in three phases. In the first phase, the dying node determines if network partition occurs, finds an available mobile node, and asks for replacement by using flooding algorithm. The dying node also decides the movement schedule of the available mobile node based on certain criteria. The second phase of the Moser protocol involves the actual movement of the mobile nodes to approach the location of the dying node. Finally, when the mobile node has reached the transmission of the dying node, it communicates to the dying nodes and moves to a desired location, where the network connectivity and coverage to the neighbors of the dying nodes are preserved.

<p><strong>Syfte:  </strong>Syftet med studien är att belysa och analysera hur revisorn arbetar för att eliminera risken för att göra väsentliga fel i årsredovisningen. Studien ska även beskriva och skapa förståelse för Revisorsnämndens och små revisionsbyråers arbete och ställningstagande till kvalitetssäkring.</p><p><strong>Metod: </strong>Utifrån ett<strong> </strong>hermeneutiskt synsätt och med en kvalitativ metod utfördes personliga intervjuer med tre små revisionsbyråer och Revisorsnämnden. Vid val av informanter tillämpades ett strategiskt urval. I studien har en abduktiv ansats använts. </p><p><strong>Slutsatser: </strong>Åtaganden för att god kvalitet ska uppnås i revisionen är revisionsprocessen, rotation på revisionsuppdrag vart sjunde år, tillämpning av analysmodell och etiska normer, FAR SRS:s kvalitetskontroller, internt kontrollsystem och kvalitetssäkring från RN.</p> / Revisionskvalitet, kvalitetssäkring, etik, moral, trovärdighet, självständighet, oberoende, objektivitet, opartiskhet

<p>When developing products, reliability is an important factor that has to be considered. For safety critical systems it is important to know the probability that an item will perform a required function without failure under stated conditions for a stated period of time. The main goal of a reliability prediction analysis is to predict the rate at which the product of a system will fail. To perform this prediction there are a number of methodologies available.</p><p>This Master Thesis proposes a model-based approach for reliability prediction calculations based on the physics of failure and supported by analysis of test-data field returns and physical models provided by the FIDES methodology. FIDES based reliability models have been integrated into a model-based diagnosis environment for seamless integration with other safety assessment analysis.</p><p>The model-based diagnosis environment used in this thesis is model-based reasoner RODON developed by Uptime Solutions AB. Components that uses the FIDES methodology have been developed in RODON, where components can be combined to systems by drag and drop method. Usage profiles that are defined according to the FIDES methodology in RODON are not system specific, which makes them reusable in other systems. The developed library of components and usage profiles makes it easy to model complex systems and perform reliability predictions according to the FIDES methodology.</p>

<p>The general aim was to examine the Swedish version of the Philadelphia Geriatric Center Multilevel Assessment Instrument, PGCMAI, in a population of old people with locomotor disability in Sweden. Specific aims were to examine whether the Swedish version of the PGCMAI meets the criteria of reliability and validity when assessing the life situation of Swedish old people with locomotor disability and to explore the pattern of the Swedish version of the instrument in respect of age and gender.</p><p>Home visits were made to 199 people aged 60 years and older in two counties in Sweden. They were interviewed using the Swedish version of the PGCMAI and tested with the Standardized Practical Equipment test, SPE. The data collected were tested for reliability and validity. Cronbach’s alpha varied from 0.27 to 0.86 among the eight domains of the PGCMAI, which concurred with other studies in the field. Validity was analyzed by explorative factor analysis. The eight new factors showed construct validity with a logical relation to the eight original domain distributions. There were also significant relationships between both the original domains of the PGCMAI and the SPE and the new factors of the PGCMAI and the SPE. Both the original Mobility domain index and the new factor correlated well with the ‘Balance and mobility’ factor in the SPE. The Cognitive domain index and the corresponding new factor show a high correlation with the ‘Cognitive functions’ factor in the SPE. The Swedish version of the PGCMAI and SPE presented a functional pattern among old men and women whereby women had deteriorated most with age, which is in agreement with other studies.</p><p>In conclusion the reliability and validity testing of the Swedish version of the PGCMAI has given satisfactory results when used with old people with locomotor disability. The Swedish version of the PGCMAI can be considered a valuable tool for measuring function in old people with locomotor disability.</p> / <p>Befolkningen åldras mer och mer, både i Europa och Sverige, som en följd av längre livslängd och låga födelsetal. Det ställer krav på samhällets resurser i form av vård och omsorg för äldre. I en tid när resurserna inte ökar blir det allt viktigare att samhällets stöd fördelas efter behov.</p><p>I den här studien utvecklades och prövades den svenska versionen av the Philadelphia Geriatric Center Multilevel Assessment Instrument, PGCMAI, på personer 60 år och äldre med rörelsehinder. Instrumentet omfattar åtta huvudsakliga funktionsområden eller domäner, Activities of Daily Living, ADL, Personal Adjustment, PADI, Physical Health, PHDI, Social, SDI, Environmental, EDSI, Time Use, Mobility, MOBI and Cognitive, CDI. Varje område består av frågor som ställs till den enskilde vid en intervju. Originalversionen av instrumentet, på amerikanska, finns i tre varianter eller längder, ’short-length’, ’mid-length’ och ’full-length’. Den svenska versionen av PGCMAI är en översättning och bearbetning av ’mid-length’ varianten.</p><p>Studiens målgrupp har varit äldre med rörelsehinder. Den har genomförts i tre steg. I det första steget skickades ett frågeformulär till 3469 personer, 60 år och äldre i två geografiska områden i Jönköpings och Värmlands län, där de tillfrågades om de hade något rörelsehinder. Det andra steget innebar att de som rapporterat rörelsehinder, 566 personer, erhöll ett nytt frågeformulär där de bl.a. tillfrågades om svårigheter att förflytta sig och ADL. Det tredje steget innebar att de som besvarade det andra frågeformuläret och accepterade besök i det egna hemmet, 199 personer, intervjuades med PGCMAI och testades med det praktiska testet, Standardized Practical Equipment test, SPE.</p><p>Det första delarbetet syftade till att utreda om den svenska versionen av PGCMAI fyllde kriterierna för reliabilitet och validitet vid bedömning av livssituationen hos äldre med rörelsehinder i Sverige.</p><p>Reliabilitet testades med Cronbach’s alpha och visade högre värde för det ursprungliga PGCMAI än för den svenska versionen, med undantag av domänerna EDSI och Time Use. Jämförelse av Cronbach´s alpha mellan äldre med rörelsehinder i den egna studien (n=199) och studie från 1982 av Lawton et al (n=590) visade likheter med högst värde för ursprungsinstrumentets domäner ADL, PADI och CDI, och lägst värde för domän SDI. Den svenska versionen av PGCMAI testades på validitet med exploratorisk faktoranalys av de 40 variabler i PGCMAI som ingick i de ursprungliga domänerna. Faktoranalysen identifierade åtta faktorer som förklarade 47% av variansen. Dessa åtta faktorer visade betydande överensstämmelse med det ursprungliga instrumentets åtta domäner. Högst korrelation med de nya faktorerna visade domänerna EDSI, SDI och ADL. MOBI i originalversionen och motsvarande faktor i den nya versionen visade högst korrelation med ’Balance and mobility’ i SPE, på motsvarande sätt erhölls samband mellan CDI och ’Cognitive functions’ i SPE.</p><p>Det andra delarbetet hade syftet att undersöka mönstret i den svenska versionen av PGCMAI utifrån ålder och kön samt i jämförelse med andra studier inom området.</p><p>Materialet analyserades i två och fyra åldersgrupper och indelat i män (n=67) och kvinnor (n=132). Analysen visade att rörelsehinder ökar med ålder både för män och kvinnor. Jämförelse mellan åldersgrupperna 60-79 år, 80-99 år, visa att rörligheten försämrades med ålder enligt domänen MOBI. För kvinnor försämrades förmågan enligt domänerna ADL, Time Use, MOBI, SDI och i alla SPE faktorerna, med ålder. Slutsatsen är att PGCMAI kunde särskilja ett funktionellt mönster bland äldre män och kvinnor med rörelsehinder och en försämring med ålder. SPE visade ett motsvarande resultat.</p><p>Slutsatsen av studien är att testningen av validitet och reliabilitet på den svenska versionen av PGCMAI har givit tillfredställande resultat när det används på gruppen 60 år och äldre med rörelsehinder. PGCMAI kunde särskilja funktionella mönster hos äldre män och kvinnor och visade att kvinnor med rörelsehinder hade försämrats mest med ålder. SPE visade liknande resultat. Den svenska versionen av PGCMAI bedöms vara ett värdefullt instrument för att mäta funktionen hos äldre med rörelsehinder och kan bli ett viktigt hjälpmedel för att ge rätt insats och i rätt omfattning.</p>

<p>In the last decade, we have seen an explosive growth in the deployment of multimedia applications on the Internet. However, the transport service provided over the Internet is not always feasible for these applications, since the network was originally designed for other types of applications. One way to better accommodate the service requirements of some of these applications is to provide a partially reliable transport service. A partially reliable transport service does not insist on recovering all, but just some of the packet losses, thus providing a lower transport delay than a reliable transport service. The work in this thesis focuses on the design, implementation, and evaluation of a partially reliable transport protocol called PRTP. PRTP has been designed as an extension to TCP in order to show that such a service could be effectively integrated with current protocol standards. An important feature of PRTP is that all modifications for PRTP are restricted to the receiver side, which means that it could be very easily deployed. The thesis presents performance results from various experiments on a Linux implementation of PRTP. The results suggest that transfer times can be decreased significantly when using PRTP as opposed to TCP in networks in which packet loss occurs. Furthermore, the thesis includes a study that investigates how users perceive an application that is based on a partially reliable service. Specifically, how users select the trade-off between image quality and latency when they download Web pages is explored. The results indicate that many of the users in the study could accept less than perfect image quality</p><p>if the latency could be shortened.</p>