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1
Frid, Matilda. "Corpus Leakage." Thesis, Konstfack, Ädellab/Metallformgivning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-4680.
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We understand the world around us through categorization and classification. But things are morecomplex than that, life is mixed up, flowing and unable to stick to labels. The main purpose ofcorpus is to contain, organize and control food and beverages. Corpus objects are also socialmarkers that have a tradition of being elitist; in both choice of material and in that they imply acertain way of usage. Corpus objects are heavily loaded with tradition and rituals. However, eatingis a common experience, it is an everyday ritual and often something we do with others. How andwhat we eat is an expression of our everyday culture. The corpus object is a body on its own terms,and I believe that this opens up for an emotional relation to these objects. Corpus has the possibilityof creating meetings, situations where we can feel and talk about something human, through anobject. Objects within the craft/art field may go beyond mere objects, and open up for newmeetings, they may do something else to us than what we are used to, and hopefully they cancommunicate with us in a new way about our culture and our everyday life. I want to create thingsthat go beyond being objects, I want to highlight the body of the object, I want the object andsubject relation to leek and I want to celebrate the fuzziness and the uncertainty of things with my work.
2
Khandka, Rupak Kumar. "Leakage behind casing." Thesis, Norwegian University of Science and Technology, Department of Petroleum Engineering and Applied Geophysics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1633.
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Achieving zonal isolation by cementing annulus space between casing and well bore is an important job in many oil wells. Gas leakage in the annulus has been recognised as a major completion problem in the oil well. A successful cement job results in complete zonal isolation on a permanent basis. To achieve these goals, various factors such as well security, casing centralization, effective mud removal, and gas migration must be considered in the design. The design of the cement must be such that it prevents micro-annuli formation, stress cracking, corrosive fluid invasion, fluid migration, and annular gas pressure. However, permanent solutions to gas leakage has not emerged and gas leaks during and after the cement is set.
In this thesis work attempt has been made to deal the fluid leakage behind casing in two levels, firstly, revealed gas migration mechanism and, secondly, analytical modeling of cement sheath failure by internal and rising temperature. Several theories have been proposed regarding gas migration. In chaper 2 some probable physio-mechanical phenomena responsible for fluid migration in the cemented casing have been described. During cement setting and hardening gas migration is attributed to ineffective hydrostatic head, fluid loss during cementing, and the differential pressure occurrence due to the gelation. Micro annulus is attributed to the cement inability to form a good bond with the casing. Cyclic pressure and temperature variations during production also lead to the debonding or tensile failure or stress crushing of the cement causing gas migration. Gas leakage may occur years after production has ceased and well has been plugged and abandoned (P&A). Explanatory mechanism includes channeling, poor mud removal, shrinkage, and high cement permeability.
In chapter 3 efforts have been made to describe the case studies regarding zonal isolation. Case 1 describes the specialized cement design and placement procedures to mitigate casing vent flows (type: improve plan to avoid problem). Case 2 depicts a new cementing approach to improve and provide long term zonal isolation. Case 3 is related to the development of a methodology to evaluate the gas migration in cement slurries (type: predicting problem before it arises).
The stress in the cement is strongly connected with temperature and pressure, as well as lithology and in-situ stress. In chapter 4 an attempt has been made to quantify the cement failure as a function of down hole conditions and geometry and to define optimum mechanical properties to sustain the induced stresses. Analytical modeling has been done on the basis of plane strain in thin wall condition. Expressions for total stresses (hoop stress in casing, hoop stress in cement, and far field stress) are used to analyzed the cement integrity based on the case study well parameters of the Kristin Oil Field of Norway, Well R-3H (chapter 5). As this oil field is HTHP type, conventional cement is found not withstanding the stresses. In most of the situation tensile failure is the mode of failure, in some cases stress crushing and debonding. Improving the elasticity of cement or it’s flexural and tensile strength appeared to be an elegant solution to prevent cement failure (debonding, radial craking, and stress crushing). In addition, improvement can be made using high grade casing pipe (high Young’s modulus, low Poisson’s ratio). In reality a thick wall high grade (Q-125, SM-125) casing program has been selected in the Kristin Oil Field. The results of this study show the relevant dependency of stress principles with differential well temperature, pressure and field stress, Young’s modulus, thickness, and diameter of casing and cement sheath are also important.
3
Gulati, Kanupriya. "Computing leakage current distributions and determination of minimum leakage vectors for combinational designs." Texas A&M University, 2003. http://hdl.handle.net/1969.1/3991.
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Analyzing circuit leakage and minimizing leakage during the standby mode of oper-
ation of a circuit are important problems faced during contemporary circuit design.
Analysis of the leakage profiles of an implementation would enable a designer to
select between several implementations in a leakage optimal way. Once such an im-
plementation is selected, minimizing leakage during standby operation (by finding
the minimum leakage state over all input vector states) allows further power reduc-
tions. However, both these problems are NP-hard. Since leakage power is currently
approaching about half the total circuit power, these two problems are of prime rel-
evance.
This thesis addresses these NP-hard problems. An Algebraic Decision Diagram
(ADD) based approach to determine and implicitly represent the leakage value for all
input vectors of a combinational circuit is presented. In its exact form, this technique
can compute the leakage value of each input vector, by storing these leakage values
implicitly in an ADD structure. To broaden the applicability of this technique, an
approximate version of the algorithm is presented as well. The approximation is done
by limiting the total number of discriminant nodes in any ADD. It is experimentally
demonstrated that these approximate techniques produce results with quantifiable
errors. In particular, it is shown that limiting the number of discriminants to a value between 12 and 16 is practical, allowing for good accuracy and lowered memory
utilization.
In addition, a heuristic approach to determine the input vector which minimizes
leakage for a combinational design is presented. Approximate signal probabilities of
internal nodes are used as a guide in finding the minimum leakage vector. Probabilistic
heuristics are used to select the next gate to be processed, as well as to select the
best state of the selected gate. A fast satisfiability solver is employed to ensure the
consistency of the assignments that are made in this process. Experimental results
indicate that this method has very low run-times, with excellent accuracy, compared
to existing approaches.
4
Johansson, Emil, and Kim Myhrman. "GSM/WCDMA Leakage Detection System." Thesis, Linköpings universitet, Elektroniksystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-66963.
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Ericsson in Linkoping houses one of the largest test laboratories within thewhole Ericsson Company. Mainly, the laboratories contain equipment forGSM, WCDMA and LTE. To test these systems, a quite large number ofRadio Base Stations are needed. The RBS's are housed in a proportionatelysmall area. Instead of sending signals through the air, cables are used totransfer the RF signals. In this way the equipment communicating witheach other are well speci ed. However this may not be the case if leakageoccur.This thesis work is about developing a system for monitoring the radioenvironment and detect leakages in the test site. There is a need to de newhat a leakage really is and measurements needs to be performed in order toaccomplish this. This report describes how the work has proceeded towardsthe nal implemented solution.
5
Pettersson, Anders. "Development of water leakage detectors." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-95257.
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One of the highest costs in many apartments for insurance companies is due to water leakage. To prevent leakage from causing damage a detector can be placed in the sensitive areas to warn if a leakage should occur. This kind of installations does however lead to high installation costs, especially in already finished buildings, since they require a lot of wiring for communication. By using a wireless detector these costs could be lowered. In order for this to be achieved a sensor which is suitable to detect such water leakage has been connected to a wireless ZigBee transmitter which in turn is able to connect to a wireless network. The advantage with using ZigBee is that it provides much better range for less power compared to other solutions. The hardware includes a circuit that modulates the input from the sensor to have a more distinct behavior. The software part handles the communication with the ZigBee network and processing of the modified input from the sensor. To achieve a reasonable sensitivity of the sensor a circular buffer has been created to trigger on an average value instead of instantaneous. After reaching a satisfying design all parts were manufactured and tested to ensure that they work according to the design. In the course of the work some ways of improvements were found and implemented, resulting in a well working prototype.
6
Khan, Mohammed Ajaz. "Leakage flow in labyrinth seals." Thesis, University of Bradford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482781.
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Rushton, Guy James. "High-pressure turbine shroud leakage." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616194.
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Demargne, Albert André Jean. "Aerodynamics of stator-shroud leakage." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620983.
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Shamout, Mohammad Nawwar. "Leakage detection in pipe networks." Thesis, University of Manchester, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525479.
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Jayakumar, Nikhil. "Minimizing and exploiting leakage in VLSI." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1249.
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Ozkan, Tulay. "Leakage Control By Optimal Valve Operation." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609419/index.pdf.
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The main function of a water distribution system is to supply water in sufficient quantity at appropriate pressure with an acceptable quality and as economically as possible. Water leakage in distribution networks may account from 5% to 50% and even larger of the total water delivered. The amount of leakage in a network is directly related to system service pressure. Therefore, reductions in high service pressures will result in considerable reductions in leakage. A methodology for leakage reduction has been presented in context of a developed computer program, LEAKSOL with two sub-programs. The first code, CODE I, provides solution by using optimization techniques with defined pressure-leakage and pressure-demand relations in order to find optimal flow control valve settings minimizing water leakage. The second one, CODE II, makes hydraulic analysis of the network in order to solve the system and to compute the amount of leakage and the amount of water consumed, by using different combinations of isolation valves generated according to the number of valves given and employing the relationships among pressure, leakage and consumption. Computer program application was performed for different scenarios in a sample network previously used in literature and also in N8-3 pressure zone of Ankara Municipal Water Supply System. Leakage reduction up to 10 % has been achieved in N8-3 pressure zone for eight valves located at the entrances of sub-zones, depending on the defined pressure-leakage relationship.
12
Stavenes, Thomas. "Subsea Hydraulic Leakage Detection and Diagnosis." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11620.
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The motivation for this thesis is reduction of hydraulic emissions, minimizing of process emergency shutdowns, exploitation of intervention capacity, and reduction of costs. Today, monitoring of hydraulic leakages is scarce and the main way to detect leakage is the constant need for filling of hydraulic fluid to the Hydraulic Power Unit (HPU). Leakage detection and diagnosis has potential, which would be adressed in this thesis. A strategy towards leakage detection and diagnosis is given. The strategy defines three approaches, define an approach, explore the approach and propose a solution. Relevant instrumentation, both existing and additional instrumentation is discussed. Relevant methods towards leakage detection and diagnosis are presented. An overview of a bewidering amount of methods is given, and basics towards application. An example from pipelines of state-of-the–art leakage detection and diagnosis is also given. A solution proposal for a simple and available leakage method with fair detectability and limited diagnostics is proposed. There tends to be a connection between performance of application and complexity. For today’s solution it would be preferable to scarify some overall performance for simplicity, considering the alternative.
13
Birek, L. "Leakage forecasting with fuzzy evolving techniques." Thesis, Coventry University, 2016. http://curve.coventry.ac.uk/open/items/33903146-10c8-45d7-9867-79ed974edb10/1.
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The amount of water lost in various leakage events in water networks in the UK not only generates economic loses for the water management companies, but more importantly, threatens supplies to households and businesses in times of severe drought.
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Wang, Frank Yi-Fei. "Preventing data leakage in web services." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120410.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 77-86).
Web services like Google, Facebook, and Dropbox are a regular part of users' lives. However, using these applications can cause sensitive data leakage both on the server and client. On the server-side, applications collect and analyze sensitive user data to monetize it. Consequently, this sensitive data can leak through data breaches or can be accessed by malicious service providers. On the client, when a user accesses a web service through the browser, sensitive user information may leak outside of the browser, e.g., to DNS interfaces or the swap space. An attacker who accesses the user device after a session has terminated can view this information. This dissertation presents two practical, secure systems, Veil and Splinter, that prevent some of this data leakage. Veil minimizes client-side information leakage from the browser by allowing web application developers to enforce stronger private browsing semantics without browser support. Splinter allows the server to properly respond to a user query without the server learning any sensitive information present in the query.
by Frank Yi-Fei Wang.
Ph. D.
15
Davies, John Bleddyn. "CO2 sequestration : the risk of leakage." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/60057/.
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The Utsira Sand is a major North Sea Saline aquifer. It is currently being utilised as a CO2 sequestration reservoir for the Sleipner project, and its large estimated storage capacity and proximity to suitable infrastructure ensures that it is an attractive prospect for further storage projects. As a forerunning CCS project it is the subject for scrutiny from environmental, industrial and governmental regulatory bodies, with the key concern being the confinement of the CO2 within the reservoir. Regulations are in place to ensure that operators monitor closely the migration of the CO2 plume within storage reservoirs and that they can demonstrate that the plume is behaving as modelled. Any unexpected behaviour of the plume requires escalation of the monitoring program and leakage would involve financial penalties in addition to remediation costs. Diligent site selection and a complete and robust understanding of the reservoir, adjacent units, and the overburden is therefore critical pre-injection. Geological features which have become apparent following CO2 injection into the Utsira Sand would suggest that the injection site was not completely understood before injection commenced. This study has contributed to a better understanding of the storage reservoir, specifically in regards to the deformed base of the Utsira Sand, which has been shown to be the result of sand remobilisation from depth in the form of sand intrusions. These intrusions, hosted within low permeability shales, represent permeable migration pathways from the deeper subsurface to the base of the Utsira Sand. Furthermore, their post-emplacement compaction has facilitated subsidence of the overlying strata. This movement, shown to affect strata up to the top of the Utsira Sand, has formed a ring of faults which projects obliquely upwards from the base of the Utsira Sand to the top of the storage reservoir. Amplitude anomalies within the overburden suggest that these zones of increased permeability have been exploited as paleo-gas migration pathways. Other amplitude anomalies within the succession overlying the Utsira Sand are also recognised. These include: high amplitude anomalies interpreted as gas accumulations within the Lower Seal, vertically focused ‘wipe out zones’ and zones of disrupted reflections interpreted as gas chimneys. The gas chimneys in particular, shown to extend to the seafloor, pose a significant leakage risk to sequestered CO2. On the basis of these observations, a plumbing system, from the Mid-Miocene to the seafloor, is presented. Potential CO2 leakage scenarios are proposed and discussed in respect to the storage ‘site’ and storage ‘complex’. It is suggested that potential future operators within this area should be aware of the features observed and appreciate the associated risk to stored CO2. It is also concluded that the viability of carbon sequestration technology as a climate change mitigation option requires that it represents an attractive proposition for those that operate the technology. Therefore it is considered that the regulation of carbon sequestration requires a finely measured balance between careful regulation and appropriate penalties for poor practice and flexibility in the interpretation of a ‘storage complex’ and ‘leakage.
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Dlamini, Moses Thandokuhle. "Combating Data Leakage in the Cloud." Thesis, University of Pretoria, 2020. http://hdl.handle.net/2263/73245.
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The increasing number of reports on data leakage incidents increasingly erodes the already low consumer confidence in cloud services. Hence, some organisations are still hesitant to fully trust the cloud with their confidential data. Therefore, this study raises a critical and challenging research question: How can we restore the damaged consumer confidence and improve the uptake and security of cloud services? This study makes a plausible attempt at unpacking and answering the research question in order to holistically address the data leakage problem from three fronts, i.e. conflict-aware virtual machine (VM) placement, strong authentication and digital forensic readiness. Consequently, this study investigates, designs and develops an innovative conceptual architecture that integrates conflict-aware VM placement, cutting-edge authentication and digital forensic readiness to strengthen cloud security and address the data leakage problem in the hope of eventually restoring consumer confidence in cloud services.
The study proposes and presents a conflict-aware VM placement model. This model uses varying degrees of conflict tolerance levels, the construct of sphere of conflict and sphere of non-conflict. These are used to provide the physical separation of VMs belonging to conflicting tenants that share the same cloud infrastructure. The model assists the cloud service provider to make informed VM placement decisions that factor in their tenants’ security profile and balance it against the relevant cost constraints and risk appetite.
The study also proposes and presents a strong risk-based multi-factor authentication mechanism that scales up and down, based on threat levels or risks posed on the system. This ensures that users are authenticated using the right combination of access credentials according to the risk they pose. This also ensures end-to-end security of authentication data, both at rest and in transit, using an innovative cryptography system and steganography.
Furthermore, the study proposes and presents a three-tier digital forensic process model that proactively collects and preserves digital evidence in anticipation of a legal lawsuit or policy breach investigation. This model aims to reduce the time it takes to conduct an investigation in the cloud. Moreover, the three-tier digital forensic readiness process model collects all user activity in a forensically sound manner and notifies investigators of potential security incidents before they occur.
The current study also evaluates the effectiveness and efficiency of the proposed solution in addressing the data leakage problem. The results of the conflict-aware VM placement model are derived from simulated and real cloud environments. In both cases, the results show that the conflict-aware VM placement model is well suited to provide the necessary physical isolation of VM instances that belong to conflicting tenants in order to prevent data leakage threats. However, this comes with a performance cost in the sense that higher conflict tolerance levels on bigger VMs take more time to be placed, compared to smaller VM instances with low conflict tolerance levels. From the risk-based multifactor authentication point of view, the results reflect that the proposed solution is effective and to a certain extent also efficient in preventing unauthorised users, armed with legitimate credentials, from gaining access to systems that they are not authorised to access. The results also demonstrate the uniqueness of the approach in that even minor deviations from the norm are correctly classified as anomalies. Lastly, the results reflect that the proposed 3-tier digital forensic readiness process model is effective in the collection and storage of potential digital evidence. This is done in a forensically sound manner and stands to significantly improve the turnaround time of a digital forensic investigation process. Although the classification of incidents may not be perfect, this can be improved with time and is considered part of the future work suggested by the researcher.Thesis (PhD)--University of Pretoria, 2020.
Computer Science
PhD
Unrestricted
17
Kathuria, Tarun. "Gate-level Leakage Assessment and Mitigation." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/101862.
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Side-channel leakage, caused by imperfect implementation of cryptographic algorithms in
hardware, has become a serious security threat for connected devices that generate and
process sensitive data. This side-channel leakage can divulge secret information in the form of
power consumption or electromagnetic emissions. The side-channel leakage of a crytographic
device is commonly assessed after tape-out on a physical prototype.
This thesis presents a methodology called Gate-level Leakage Assessment (GLA), which
evaluates the power-based side-channel leakage of an integrated circuit at design time. By
combining side-channel leakage assessment with power simulations on the gate-level netlist,
GLA is able to pinpoint the leakiest cells in the netlist in addition to assessing the overall
side-channel vulnerability to side-channel leakage. As the power traces obtained from power
simulations are noiseless, GLA is able to precisely locate the sources of side-channel leakage
with fewer measurements than on a physical prototype. The thesis applies the methodology
on the design of a encryption co-processor to analyze sources of side-channel leakage.
Once the gate-level leakage sources are identified, this thesis presents a logic level replacement
strategy for the leakage sources that can thwart side-channel leakage. The countermeasures
presented selectively replaces gate-level cells with a secure logic style effectively removing
the side-channel leakage with minimal impact in area. The assessment methodology along
with the countermeasures demonstrated is a turnkey solution for IP module designers and
is also applicable to larger system level designs.Master of Science
18
Ahrabi, Nina. "Low Leakage Asymmetric Stacked Sram Cell." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500021/.
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Memory is an important part of any digital processing system. On-chip SRAM can be found in various levels of the memory hierarchy in a processor and occupies a considerable area of the chip. Leakage is one of the challenges which shrinking of technology has introduced and the leakage of SRAM constitutes a substantial part of the total leakage power of the chip due to its large area and the fact that many of the cells are idle without any access. In this thesis, we introduce asymmetric SRAM cells using stacked transistors which reduce the leakage up to 26% while increasing the delay of the cell by only 1.2% while reducing the read noise margin of the cell by only 15.7%. We also investigate an asymmetric cell configuration in which increases the delay by 33% while reduces the leakage up to 30% and reducing the read noise margin by only 1.2% compared to a regular SRAM cell.
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Suryawardani, I. Gusti Ayu Oka. "Tourism leakage of accommodation in Bali." Thesis, Paris 1, 2015. http://www.theses.fr/2015PA010071/document.
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Le tourisme est le fer de lance de l'économie balinaise. Mais, les fruits de cette économie du tourisme ne bénéficient pas à toutes les classes de la société balinaise. Cela est dû, entre autres, au manque à gagner lorsque cette industrie importe par exemple des produits ou des services pour répondre aux besoins des touristes (alimentation pour la restauration par exemple). Le calcul du manque à gagner pour l'économie balinaise n’a jamais été fait auparavant. Pour cela, cette recherche est nécessaire. Les objectifs de la recherche étaient : de calculer le manque à gagner pour l'économie balinaise dans le secteur du logement pour les touristes en micro-économie (niveau industriel) ; d'estimer le manque à gagner pour le tourisme balinais dans le secteur de l'hébergement touristique en macroéconomie (au niveau provincial) ; d'évaluer l'impact de la subvention gouvernementale et la réduction des importations dans l' industrie du tourisme, les opportunités d'emploi et la distribution des revenus ; d'évaluer la perception et le choix des touristes internationaux face aux offres de produits importés et locaux, et aussi d'évaluer l'opinion des touristes sur le constat : est-ce que les dépenses des touristes pendant leur voyage à Bali bénéficient à la société balinaise ? ; et d'évaluer les opinions des gestionnaires des hôtels sur l'utilisation des produits importés et des produit locaux pour la consommation des touristes ; de créer une stratégie afin de minimiser le manque à gagner dans le secteur du tourisme pour l'économie balinaise. La recherche est basée sur les approches quantitatives et qualitatives. Les données primaires ont été recueillies par la méthode du sondage sur quatre destinations touristiques, à savoir : Kuta, Nusa Dua, Sanur et Ubud, auprès d'un échantillon de 79 hôtels selon la méthode de probabilité proportionnelle à la taille qui est divisée en trois échantillons en grappes : hôtels classés 1, 2 et 3 étoiles ; hôtels classés 4 & 5 étoiles et hôtels privés (non-chain) ou appartenant à une chaine hôtelière (chain) ; hôtels non-classés. Nombre de répondants 600 touristes internationaux qui étaient en vacances à ce moment-là. Le calcul du manque à gagner dans l'analyse micro a été mené selon la méthode d'Unluonen et. al. (2011), tandis que l'analyse macro a été faite selon la méthode de Thorbecke (1988) en utilisant l'approche de la matrice de comptabilité sociale (MCS) de la province de Bali de l'année 2010. La perception et le choix des touristes internationaux vis-à-vis des produits importés et locaux ont été analysé selon le logiciel JMP tandis que les stratégies de la minimisation du manque à gagner dans l'économie touristique balinaise ont été créées selon la méthode de l'ISM (interpretive Structural Modelling). [...] Les touristes internationaux choisissent de façon significative les produits locaux et ils sont prêts à dépenser leur argent au bénéfice des populations locales. Les gestionnaires des hôtels sont prêts à utiliser les produits locaux tant que l’offre est suffisante pour remplacer les produits importés. Les stratégies pour minimiser le manque à gagner pour le tourisme à Bali : optimiser les potentiels des produits locaux ; développer l'agriculture et l' élevage, réduire les produits importés pour la consommation des touristes, augmenter l'exportation des produits locaux, augmenter la qualité des produits locaux ainsi que la qualité des ressources humaines locales, renforcer la société locale, inciter le gouvernement à mettre en œuvre une politique de minimisation du manque à gagner dans l'économie touristique, limiter les investissements étrangers dans le secteur du logement touristique, stabiliser les fluctuations des taux de change, augmenter le rôle du Ministère des affaires étrangères, du ministère de l'industrie, du Ministère du commerce ainsi que le rôle du Ministère du tourisme et de l'économie créative afin de réduire ledit manque à gagnerTourism has become the leading economic sector in Bali Province of Indonesia. However, the economic impacts of tourism have not been convinced to be full y beneficial for Balinese community. One of the reasons is tourism leakage that occurs when the industry imports both products and services to support tourism industry in Bali. So far, the amount of tourism leakage in Bali has not been calculated yet. Therefore, there is a need to ascertain the current amount of leakage in Bali tourism. The objectives of the study are: (i) to calculate the amount of tourism leakage from accommodation sector in Bali at micro (industrial) level; (ii) to calculate the amount of tourism leakage from accommodation sector in Bali at macro (regional) level; (iii) to evaluate the impacts of government subsidies and import reduction by accommodation sector on tourism leakage, job opportunity and income distribution; (iv) to evaluate the perception and preference of foreign tourists on imported and local products as well as the willingness of foreign tourists to spend their money to benefit of Balinese people; (v) to evaluate the points of view of hotel managers related to imported and local products as well as their willingness in reducing the use of imported product and (vi) to develop strategies in minimizing tourism leakage in accommodation in Bali. Research was designed through quantitative and qualitative approaches. Data was collected by using survey method at four main tourist destinations in Bali, namely: Kuta, Nusa Dua, Sanur and Ubud. There were 79 hotels selected based upon probability proportional to size sampling method which consists of three clusters namely 1,2,3 Star-rated, 4&5 Star-rated either chain and non-chain and Non Star-rated hotels. The number of respondents was 600 foreign tourists were selected as respondents. Calculation of tourism leakage on micro analysis was undertaken by using a method developed by Unluonen, et. al. (2011), meanwhile, on macro analysis was carried out by using a method proposed by Thorbecke ( 1988) which was based on the Social Accounting Matrix (SAM) of Bali 2010. Perception and preference of foreign tourists on imported and local products were analyzed by using JMP program, meanwhile, Interpretative Structural Modelling (ISM) was undertaken to develop strategies. The results show that based on the micro analysis, the highest tourism leakage of accommodation sector in Bali is at 4&5 Star-rated chain hotels (51.0 %), followed by 4&5 Star-rated non-chain hotels (22.7 %), 1,2&3 Star-rated hotels (12.0 %), Non-star rated hotels (8.8 %), and with the average leakage of 18.8 %. Based on macro analysis, tourism leakage of accommodation sector in Bali are as follow: (i) Leakage of Non Star-rated hotels is 2.0 %; (ii) Leakage of 1,2&3 Star-rated hotels is 15.7 %; (iii) Leakage of 4&5 Star-rated non-chain hotels is 7.1 %, (iv) Leakage of 4&5 Star-rated chain hotels is 55.3%; and (v) Average leakage of all types of accommodation is 19.5%. Foreign tourists significantly look for local products and are willing to spend their money for Balinese people. Hotel managers are willing to use local product as long as local products are available to substitute the imported products. Strategies for minimization tourism leakage are optimizing the potential of local products, develop agriculture and livestock; reduce the use of imported products for tourists, improve quality of local products and human resources, empower community, urge government to develop and implement supporting policies in minimizing tourism leakage, establish policy on restriction of foreign investment on accommodation in Bali, improve the role of Ministry of Foreign Affairs, Ministry of Industry, Ministry of Trade and Ministry of Tourism and Creative Economy. 7 Ps of marketing mix on service: product, price, place, promotion, people, process and physical evidence need to be implemented in order to support sustainable tourism in Bali
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Peddiraju, Naga Venkata Satya Pravin Kumar. "Modeling of cryogen leakage through composite laminates." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/1329.
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Cryogenic composites find critical application in the manufacture of fuel tanks for reusable launch vehicles due to significant reduction in overall structural weight of the tank. These fuel tanks contain pressurized cryogen such as hydrogen at cryogenic temperatures. Exposure to varying temperatures and mechanical loads resulting from flight cycle, containment of pressurized cryogen causes thermo-mechanical loading of the composite. The thermo-mechanical loading cycles combined with anisotropy of the composite and mismatch in the thermal and mechanical properties of fibers and matrix lead to transverse matrix cracks (TMC) in each ply. TMC in adjacent plies intersect in localized regions at ply interfaces called crack junctions, which open up due to delamination on application of thermo-mechanical load. TMC and crack junctions usually form a network of leakage paths that assists leakage of cryogen through the composite. In this study, the volumetric flow rate of cryogen leaking through a damaged cross-ply composite with five plies is determined by estimating the effective conductance of the leakage paths. For a given damage state and applied load, crack junction and TMC openings are obtained by finite element analysis. A computational fluid dynamics model is first used to estimate the effective conductance of a leakage path to hydrogen leakage and then a simplified analytical model is used to compute the effective conductance from individual conductances of each crack junction and TMC through a series-parallel combination. A single phase flow model is considered for the numerical analysis of hydrogen flow through TMC and crack junctions. The simulations are carried out using a commercial computational fluid dynamics software, FLUENT. Parametric studies are carried out to investigate the dependence of leak rate of hydrogen on the irregularities of the TMC geometry and TMC, crack junction openings. The simplified model predictions of the effective conductance for the five ply composite show good comparison with numerical simulations.
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Qi, Te. "Inverse modeling to predict effective leakage area." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45942.
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The purpose of this research is to develop a new approach to estimate the effective leakage area using the inverse modeling process as an alternative to the blower door test. An actual office building, which is the head quarter of Energy Efficiency Hub, was used as an example case in this study.
The main principle of the inverse modeling process is comparing the real monitor boiler gas consumption with the result calculated from the EnergyPlus model with a dynamic infiltration rate input to find the best estimation of the parameter of effective leakage area (ELA). This thesis considers only the feasibility of replacing the blower door test with the calibration approach, so rather than attempting an automated calibration process based on inverse modeling we deal with generating a first estimate and consider the role of model uncertainties that would make the proposed method less feasible.
There are five steps of the whole process. First, we need to customize our own actual weather data (AMY) needed by the energy model (EnergyPlus model), which can help increase our quality of the result. Second, create the building energy model in EnergyPlus. Third, create a multi-zone model using CONTAM with different ELA estimation of each facade to calculate the dynamic infiltration rate of each ELA estimate. Fourth, input the dynamic infiltration rate got from the CONTAM model to EnergyPlus model and output the boiler energy consumption. Fifth, compare the boiler gas consumption from the model and the real monitor data and find the best match between the two and the corresponding ELA, which gives the best estimate from the whole inverse modeling process.
From the simulation result comparison, the best estimation of the total building ELA from the inverse modeling process is the 23437cm2 at 4pa, while the result from the blower door test is 10483cm2 at 4pa. Because of the insufficient information of the building and also the uncertainty of the input parameters, the study has not led to a definite statement whether the proposed calibration of the ELA with consumption data can replace a blower door test to get an equally valid or even better ELA estimate, but it looks feasible. As this this case study is done in a deterministic context, the full feasibility test should be conducted under uncertainty. A first step towards this will talk be discussed in chapter 4.
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Haynes, Jonathan Mark. "Axial piston pump leakage modelling and measurement." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/55178/.
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This thesis is concerned with the dominant leakage characteristics of an axial piston pump. Results have been obtained from a combination of analysis, Computational Fluid Dynamics (CFD) and experimental work, and have added to existing knowledge in this field. The measurement of slipper leakage within an axial piston pump is impossible due to additional leakage from the pistons and between the cylinder barrel and port plate. It may only be determined by analysis and this aspect has been studied via a new CFD simulation. Further progress has been made experimentally on slipper leakage. A new test apparatus was designed and developed by the author and comparisons have been made with parallel analytical work. Previous research in this area has concentrated on single-landed slippers and leakage rates from such slippers have been examined, however only under static conditions. The work in this thesis is the first to consolidate experimental studies on multiple-land slippers, and the first to measure slipper leakage under dynamic conditions. These results have been compared with both CFD simulations and a new theoretical study undertaken in parallel with this work. The new test apparatus allowed measurement of both leakage and groove pressure under a range of operating conditions. It was established that the presence of a groove reduces the restoring moment produced, and hence enables the slipper to operate with an appropriate angle of tilt, thus permitting hydrodynamic lift to more readily exist. However, this occurs at a cost of increased leakage. In addition to the experimental work on slippers, the time-varying pressures within selected cylinders of an axial piston pump were measured. In parallel, a fully dynamic CFD model of a pump was produced. This model included all leakage paths from the pump. It was discovered that the port plate leakage dominated the overall leakage, with slipper leakage still being significant, but with piston leakage insignificant. This model was also used to predict the flow and pressure ripple from the pump and the predictions were compared with experimental measurements.
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Markov, Stanislav Nikolaev. "Gate leakage variability in nano-CMOS transistors." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/771/.
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Gate leakage variability in nano-scale CMOS devices is investigated through advanced modelling and simulations of planar, bulk-type MOSFETs. The motivation for the work stems from the two of the most challenging issues in front of the semiconductor industry - excessive leakage power, and device variability - both being brought about with the aggressive downscaling of device dimensions to the nanometer scale. The aim is to deliver a comprehensive tool for the assessment of gate leakage variability in realistic nano-scale CMOS transistors. We adopt a 3D drift-diffusion device simulation approach with density-gradient quantum corrections, as the most established framework for the study of device variability. The simulator is first extended to model the direct tunnelling of electrons through the gate dielectric, by means of an improved WKB approximation. A study of a 25 nm square gate n-type MOSFET demonstrates that combined effect of discrete random dopants and oxide thickness variation lead to starndard deviation of up to 50% (10%) of the mean gate leakage current in OFF(ON)-state of the transistor. There is also a 5 to 6 times increase of the magnitude of the gate current, compared to that simulated of a uniform device. A significant part of the research is dedicated to the analysis of the non-abrupt bandgap and permittivity transition at the Si/SiO2 interface. One dimensional simulation of a MOS inversion layer with a 1nm SiO2 insulator and realistic band-gap transition reveals a strong impact on subband quantisation (over 50mV reduction in the delta-valley splitting and over 20% redistribution of carriers from the delta-2 to the delta-4 valleys), and enhancement of capacitance (over 10%) and leakage (about 10 times), relative to simulations with an abrupt band-edge transition at the interface.
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Kendall, Haydn G. "Investigation of leakage flux in transformer tanks." Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329641.
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Lewis, Leo Vivian. "Deformation and leakage of aeroengine casing flanges." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320346.
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Laughlin, William Edward. "Angiogenesis and vascular leakage in diabetic retinopathy." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10043874/.
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Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and a leading cause of blindness. Increased vascular permeability in the retina following blood-retinal barrier (BRB) breakdown is a clinically significant event and a major cause of vision loss. VEGF blockade, despite being the only treatment to improve visual acuity, has a limited effectiveness for a majority of patients. A significant proportion of patients develop resistance to treatment, which implies that other factors are also involved in the pathology of this disease. There is currently a major unmet clinical need for therapeutics which target the early stages of DR prior to the onset of overt vascular symptoms. The aim of this thesis was to investigate early diabetes-induced changes to the retina and their effects on the vasculature, in order to identify novel potential therapeutic targets. This was achieved by investigating the effects of high glucose and glycated albumin on the vasculature using the mouse metatarsal assay, an ex vivo model of angiogenesis and the effects of diabetes on the retina with the streptozotocin-induced diabetic mouse. Both high glucose and glycated albumin altered angiogenesis in the metatarsal assay. Investigation of the diabetic mouse retina revealed evidence of increased inflammation and oxidative stress at the cellular and molecular level, accompanied with evidence of vascular leakage. qPCR analysis revealed an increase in Angptl6 and Lrg1 expression of which had not been investigated in the diabetic mouse retina before. Studies with transgenic mouse models implied that Lrg1 is involved in the early stages of pathophysiology of DR and may be a suitable therapeutic target prior to the onset of overt vascular symptoms.
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Sihler, Joachim 1971. "A low-leakage 3-way silicon microvalve." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27105.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaves 127-136).
This thesis presents an electrostatically actuated silicon microvalve designed for use in a miniature gas chromatography system for sample preparation and injection. In contrast to prior art, this design combines an integrated low voltage electrostatic microactuator as well as tight sealing capability. The device uses only silicon and silicon dioxide, which allows it to be used in a gas chromatography system for a wide range of chemically compatible gases. Using a 3-way design, the valve can switch an input gas flow to either of two output ports, which helps reducing wafer space consumption if used in a valve array, by combining two 2-way on/off valves into one device. After a thorough discussion of prior art in microvalve technology, the design and modeling of the microvalve is presented. A detailed discussion of the microfabrication issues is given, along with a final process plan. One-sided prototype valves were fabricated and their performance was characterized. Leakage rates on the order of 10⁻⁶ atm-cc/sec have been measured. The prototype valves are capable of switching inlet pressures of typically 8 psi with open flow rates of 8 sccm Nitrogen at an operation voltage of 23 V.
by Joachim Sihler.
Ph.D.
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Durschlag, Hannah (Hanna Rebekah). "Air leakage of Insulated Concrete Form houses." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72627.
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Thesis (S.M. in Building Technology)--Massachusetts Institute of Technology, Dept. of Architecture, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 59-63).
Air leakage has been shown to increase building energy use due to additional heating and cooling loads. Although many construction types have been examined for leakage, an exploration of a large number of Insulated Concrete Form (ICF) houses has not yet been completed. This thesis first collects 43 blower door tests of recently built ICF houses in North America. These are then examined and compared with a large collection of blower door tests of wood-stud construction. There is a 1.2% difference between ICF and wood-stud air leakage, with a very similar range. This range is mainly attributed to leakage from the attic space and cracks around windows based on a thorough investigation of two specific ICF houses in Nashville, TN. Using an EnergyPlus building model, the difference in air leakage between a typical ICF and wood-stud house in Chicago and Phoenix is not found to cause a significant gap in energy use. However, the range in air leakage does affect the amount of energy a single-family house consumes.
by Hannah Durschlag.
S.M.in Building Technology
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Smith, Adam (Adam Davidson) 1977. "Maintaining secrecy when information leakage is unavoidable." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28744.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 109-115).
(cont.) We apply the framework to get new results, creating (a) encryption schemes with very short keys, and (b) hash functions that leak no information about their input, yet-paradoxically-allow testing if a candidate vector is close to the input. One of the technical contributions of this research is to provide new, cryptographic uses of mathematical tools from complexity theory known as randomness extractors.
Sharing and maintaining long, random keys is one of the central problems in cryptography. This thesis provides about ensuring the security of a cryptographic key when partial information about it has been, or must be, leaked to an adversary. We consider two basic approaches: 1. Extracting a new, shorter, secret key from one that has been partially compromised. Specifically, we study the use of noisy data, such as biometrics and personal information, as cryptographic keys. Such data can vary drastically from one measurement to the next. We would like to store enough information to handle these variations, without having to rely on any secure storage-in particular, without storing the key itself in the clear. We solve the problem by casting it in terms of key extraction. We give a precise definition of what "security" should mean in this setting, and design practical, general solutions with rigorous analyses. Prior to this work, no solutions were known with satisfactory provable security guarantees. 2. Ensuring that whatever is revealed is not actually useful. This is most relevant when the key itself is sensitive-for example when it is based on a person's iris scan or Social Security Number. This second approach requires the user to have some control over exactly what information is revealed, but this is often the case: for example, if the user must reveal enough information to allow another user to correct errors in a corrupted key. How can the user ensure that whatever information the adversary learns is not useful to her? We answer by developing a theoretical framework for separating leaked information from useful information. Our definition strengthens the notion of entropic security, considered before in a few different contexts.
by Adam Davison Smith.
Ph.D.
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Reid, Kevin John. "Effect of leakage flows on turbine performance." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613838.
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Wampler, Christopher. "Information leakage in encrypted IP video traffic." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54287.
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We show that information leakage occurs in video over IP traffic, including for encrypted payloads. It is possible to detect events occurring in the field of view of a camera streaming live video through analysis of network traffic metadata including arrival time between packets, packets sizes, and video stream bandwidth. Event detection through metadata analysis is possible even when common encryption techniques are applied to the video stream such as SSL or AES. We have observed information leakage across multiple codes and cameras. Through timestamps added to the x264 codec, we establish a basis for detectability of events via packet timing. Laboratory experiments confirm that this event detection is possible in practice and repeatable. By collecting network traffic captures from over 100 Skype video calls we are able to see the impact of this information leakage under a variety of conditions.
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Mistry, Jatin N. "Leakage power minimisation techniques for embedded processors." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/348805/.
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Leakage power is a growing concern in modern technology nodes. In some current and emerging applications, speed performance is uncritical but many of these applications rely on untethered power making energy a primary constraint. Leakage power minimisation is therefore key to maximising energy efficiency for these applications. This thesis proposes two new leakage power minimisation techniques to improve the energy efficiency of embedded processors. The first technique, called sub-clock power gating,can be used to reduce leakage power during the active mode. The technique capitalises on the observation that there can be large combinational idle time within the clock period in low performance applications and therefore power gates it. Sub-clock power gating is the first study into the application of power gating within the clock period, and simulation results on post layout netlists using a 90nm technology library show 3.5x, 2x and 1.3x improvement in energy efficiency for three test cases: 16-bit multiplier, ARM Cortex-M0 and Event Processor at a given performance point. To reduce the energy cost associated with moving between the sleep and active mode of operation, a second technique called symmetric virtual rail clamping is proposed. Rather than shutting down completely during sleep mode, the proposed technique uses a pair of NMOS and PMOS transistors at the head and foot of the power gated logic to lower the supply voltage by 2Vth. This reduces the energy needed to recharge the supply rails and eliminates signal glitching energy cost during wake-up. Experimental results from a 65nm test chip shows application of symmetric virtual rail clamping in sub-clock power gating improves energy efficiency, extending its applicable clock frequency range by 400x. The physical layout of power gating requires dedicated techniques and this thesis proposes dRail, a new physical layout technique for power gating. Unlike the traditional voltage area approach, dRail allows both power gated and non-power gated cells to be placed together in the physical layout to reduce area and routing overheads. Results from a post layout netlist of an ARM Cortex-M0 with sub-clock power gating shows standard cell area and signal routing are improved by 3% and 19% respectively. Sub-clock power gating, symmetric virtual rail clamping and dRail are incorporated into power gating design flows and are compatible with commercial EDA tools and gate libraries.
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Muralidharan, Nair Mithun. "Statistical Leakage Estimation Using Artificial Neural Networks." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1413471610.
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Nsanzubuhoro, Rene. "Pressure-based leakage characterisation of bulk pipelines." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30938.
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Water losses in distribution systems are a huge problem internationally and also in South Africa where more than a third of the water entering the water supply networks is lost through pipe leaks. With water demand increasing due to population growth and urbanisation, water resources are under greater stress and water supply failures are becoming more common. A great deal of work has been done over the past two decades on managing water losses in distribution systems. The Water Loss Task Force of the International Water Association (IWA) played a leading role in this effort, with the “IWA water balance” now widely used as a basis in municipal water loss programs. One of the areas that have received relatively little attention is leakage on bulk pipeline systems. Bulk pipelines connect water treatment plants to bulk reservoirs and distribute water from reservoirs to different towns or water supply zones. Bulk pipes may be operated using pumps or gravity, and generally do not supply consumers directly. It is difficult to determine what the water losses in a bulk pipeline are, as the high flow rates make it impractical or prohibitively expensive to measure flow rates at both ends of these pipelines. Cheaper solutions, such as clamp-on ultrasonic flow meters or reservoir drop tests, are prone to problems and do not have the required accuracy. Due to the lack of reliable and effective methods, water losses on bulk pipes are often assumed to be 2 or 3 %. However, these losses may, in fact, be much greater, and due to the large flow of water transported by bulk pipelines, even small fractions of losses represent large volumes of water. The aim of this project was to develop a method for identifying the size and type of leak present in real bulk water pipelines with minimal disturbance to the operation of the infrastructure. This was achieved by developing a mobile device called the pipe condition assessment equipment (PCAE), which uses pressure testing in combination with the latest models on the behaviour of leaks areas with pressure to assess the condition of the bulk pipeline. To verify the efficacy of the PCAE, the device was first tested on three uPVC pipes with known leakage characteristics in the laboratory (a 12mm round hole, 100mm by 1mm circumferential crack and a 100mm by 1mm longitudinal crack). As expected, the round hole had very small head-area slopes which are negligible, whilst the circumferential crack showed a negative head area slope and the longitudinal crack portrayed a large positive head-area slope. These results were consistent with previous laboratory experiments that investigated the behaviour of round holes and longitudinal and circumferential cracks. Bulk water suppliers and municipalities were then approached to take part in the study. Several bulk pipelines were tested using the PCAE. The results of the field test are discussed in terms of the pre-testing procedures to prepare for the tests, their repeatability and the effectiveness of the device to detect, quantify and characterise leakage on the pipeline. For pipelines with undetectable leakage, a non-intrusive technique that uses a dynamic pressure drop signature from an isolated pipe, to detect and quantify undetectable leakage, was developed. The leakage characteristics of the isolated pipe were estimated from the pressure vs time data. In summary, if the pressure remained constant the pipe was without a leak. If the pressure dropped, a novel mathematical model was fitted to the pressure vs time curve, using the known pipe properties, to determine the characteristics of the leak or leaks present in the pipe. Overall, the PCAE was capable of assessing the extent of leakage on a range of pipe materials, diameters and lengths. It was found that out of the eleven bulk pipelines tested in this study, three could not be tested due to dysfunctional isolation valves and failed connection points. The other eight pipelines that were successfully tested were found to be leaking. The effective initial leak areas for the tested pipelines ranged from 4.88mm2 to 137.66mm2 , whilst the effective head-area slope ranged from 0.0032 mm2 /m to 3.14 mm2 /m and the N1 leakage exponents were found to range from 0.56 up to 1.09. Finally, since there are no well-founded performance indicators for bulk systems, this study also described the findings from analyses of several potential performance indicators using the data from the bulk pipelines tested using the PCAE. The challenges in comparing water losses of different bulk pipelines are highlighted. Based on this, it was found that because every bulk pipeline has its unique characteristic regarding structural parameters such as diameter, pipe material, type of couplings, and operating pressure, the preferred performance indicator for assessing water losses in bulk systems mainly depends on the purpose of the analysis.
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Martin, Daniel P. "Leakage resilient symmetric cryptography : theory and practice." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702904.
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Alneyadi, Sultan Saif. "Data Leakage Prevention Using Statistical Semantics Analysis." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/366590.
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Protecting confidential data from being leaked into the public domain is a growing concern among organisations and individuals. Traditionally, data confidentiality has been preserved utilising common security procedures contained within ‘Information Security Policies’, which have limited scope to be individually tailored, along with conventional security mechanisms such as firewalls, virtual private networks and intrusion detection systems. Unfortunately, these standard mechanisms lack the necessary pro-activeness and dynamism required in today’s world of ever-changing technology and innovative threats to digital security. Another consideration is the constantly variable nature of how data are manifested through multitudes of leaking channels to be satisfactorily effective in preventing the serious and potentially disastrous consequences of such leaks. Therefore, there has been an industry-wide drive towards mitigating these drawbacks using more effective instruments. Recently, Data Leakage Prevention Systems (DLPSs) have been introduced as dedicated mechanisms to detect and prevent the leakage of confidential data that are in use, in transit and at rest. DLPSs use various techniques to analyse the context and content of confidential data to detect and prevent leakages. Contextual analysis usually studies the attributes surrounding confidential data such as senders, recipients, timing, data size and data format. In contrast, content analysis focuses on identifying confidential content using techniques such as regular expression, data fingerprinting and statistical analysis. Equipped with contextual analysis, content analysis or a combination of both, a wide range of DLPSs have been proposed in academia and industry, each with its own rewards and drawbacks.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Infromation and Communication Technology
Science, Environment, Engineering and Technology
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LUO, Huajiang. "Information leakage and sharing in decentralized systems." Digital Commons @ Lingnan University, 2018. https://commons.ln.edu.hk/otd/35.
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This thesis presents two essays that explore firms’ incentive to share information in a multi-period decentralized supply chain and between competing firms. In the first essay, we consider a two-period supply chain in which one manufacturer supplies to a retailer. The retailer possesses some private demand information about the uncertain demand and decides whether to share the information with manufacturer. If an information sharing agreement is achieved, the retailer will share the observed demand information truthfully to the manufacturer. Then the selling season with two periods starts. In each period, the manufacturer decides on a wholesale price, which the retailer considers when deciding on the retail price. The manufacturer can observe the retailer's period-1 decision and the realized period-1 demand, and use this information when making the period-2 wholesale price decision. Thus, without information sharing, the two firms play a two-period signaling game. We find that voluntary information sharing is not possible because it benefits the manufacturer but hurts the retailer. However, different from one-period model, in which no information sharing can be achieved even with side payment, the manufacturer can make a side payment to the retailer to induce information sharing when the demand range is small. Both firms benefit from more accurate information regardless whether the retailer shares information. We also extend the two-period model to three-period model and infinite-period model, we find that the above results are robust. The second essay studies the incentives for information sharing between two competing firms with different production timing strategies. Each firm is planning to produce a new (upgraded) product. One firm adopts routine timing, whereby her production time is fixed according to her tradition of similar or previous models of the product. The other firm uses strategic timing, whereby his production time can be strategically chosen: be it before, simultaneously with, and after the routine firm. The two firms simultaneously choose whether or not to disclose their private demand information, make their quantity decisions based on any demand information available, and then compete in the market. We find that when the demand uncertainty is not high, both firms sharing information is the unique equilibrium outcome. Exactly one firm (the routine firm) sharing information can arise in equilibrium when the demand uncertainty is intermediate. These results are in stark contrast to extant literature which has shown that, for Cournot competitors with substitutable goods, no firm is willing to share demand information. Production timing is thus identified as a key driving force for horizontal information sharing, which might have been overlooked before. Surprisingly, when the competition becomes more intense, firms are more willing to share information. It is the information asymmetry that fundamentally change the strategic firm’s timing. We highlight the impact of signaling demand information for an early-production firm on the timing strategies, under different information sharing arrangements.
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Hansen, Douglas Dale. "Analytic modeling of leakage in confined aquifer systems /." Diss., ON-CAMPUS Access For University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations", 2002. http://www.lib.umn.edu/articles/proquest.phtml.
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Gopalan, Ranganath. "Leakage power driven behavioral synthesis of pipelined asics." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001064.
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Chen, Bo. "Role of blood-brain barrier leakage during stroke." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3403853.
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Yildirim, Ender. "Design And Implementation Of Low Leakage Mems Microvalves." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613771/index.pdf.
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This thesis presents analysis, design, implementation, and testing of electrostatically actuated MEMS microvalves. The microvalves are specifically designed for lab-on-a-chip applications to achieve leakage ratios below 0.1 at pressure levels in the order of 101 kPa.
For this purpose, two different microvalves are presented in the study. In the proposed designs, electrostatic actuation scheme is utilized to operate the microvalves in normally open and normally closed modes. Characterization of normally open microvalves show that, microvalves with radii ranging between
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Bartos, Elias, and Kristian Ahlberg. "Minimizing of Drain Leakage on a Scania Retarder." Thesis, KTH, Fordonsdynamik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48587.
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To enhance the drivability and increase safety a major part of Scania’svehicles is fitted with a retarder. The retarder is a complementary brake system that assists the vehicles mechanical brakes. When running a retarder some oil leakage can occur. The main source to the leakage is oil sump ventilation but there is also some contribution from the solenoid valve block that controls the retarder. Test results from the test rig shows that with rather simple methods the oil leakage in form of oil mist can be captured. The efficiency of for instance concept 1 with half the volume and a chicane interior was as high as 99 to 100 %. For the concept 2 with the expanded metal filter the efficiency was in the order of 96 to 100 %. From testing it has also become clear that there is a problem to feed the oil back into the oil sump. Initial tests shows that the retarder is rather sensitive regarding the placing of the feedback channel. It is considered that the best option is to only use the feedback channel that enters the internal drain of the retarder. Measurements show that the airflow in the tube from the accumulator could reach velocities up to 67 m/s. It is considered that the best solution is to have two separate chambers, one for the accumulator and one for the oil sump ventilation, the safety valve and the proportion valve. The reason for this is that the combination of oil in a chamber together with high airflow from the accumulator is disastrous and the retarder leaks far worse compared to original. The conclusion is therefore that it is important to separate air from the accumulator from places where oil can occur. Tests also revealed that the size of an external volume is not of any great importance when it comes to colleting oil. There was no significant difference in between of using a volume of 0.64 l or 0.19 l. However regarding overfilling it is favorable to have a larger volume since this increases the retarder’s capability to withstand oil leakage when it is overfilled.
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Johansson, Andreas. "Model-based leakage detection in a pressurized system." Licentiate thesis, Luleå tekniska universitet, Signaler och system, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17121.
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Fault detection and isolation is a potentially powerful tool for achieving security and effective maintenance in various types of processes. The motivation for performing leakage detection in the coal injection plant is mainly the inflammability of pulverized coal. A leakage of air into an injection vessel could have catastrophic consequences. Nonlinear physical gray-box models of the plant are developed. Values of the unknown parameters are estimated by identification. Observers are constructed for these models and the residual is shown to be an estimate of the leakage flow.The Generalized Likelihood Ratio is employed to compare the residual to predefined typical leakage functions. When evaluating the residual, it is desirable to represent the essential dynamics concisely while removing irrelevant behaviour and noise. In order to ease the computational burden while preserving the essential dynamic behaviour of a leakage, a truncated Laguerre series representation of the signals is used. The developed algorithms are implemented in the commercially available product SafePCI and installed at SSAB Tunnplåt, Luleå.Godkänd; 1999; 20070403 (ysko)
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Eliasson, Kerstin. "Urinary leakage and physical activity in young women /." Stockholm : Karolinska institutet, 2005. http://diss.kib.ki.se/2005/91-7140-530-5/.
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Durgadoo, Jonathan [Verfasser]. "Controls and impact of Agulhas leakage / Jonathan Durgadoo." Kiel : Universitätsbibliothek Kiel, 2013. http://d-nb.info/1042440271/34.
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Palafox, Pepe. "Gas turbine tip leakage flow and heat transfer." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427699.
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Borg, Andreas, and Christopher Karlsson. "A study of air leakage around window constructions." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119964.
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Det finns flera kritiska punkter i en byggnad där luft kan ta sig in, exempelvis genomföringar i klimatskalet för elrör och vattenrör, anslutningar i klimatskalet i form av dörrar och fönster samt skarvar i byggandens tätskikt. Tätningen kring just fönster är en av de detaljer som det tilldelas mest resurser till. Två grundläggande moment är avgörande för hur stort luftläckage det kan bli; hur tätskiktet avslutas kring fönsteröppningen och vilken tätningsprincip som används. Med detta som en grund har syftet med den här studien varit att ta fram vilka fler parametrar kring en fönsterkonstruktion som är avgörande för dess lufttäthet samt vilka olika typer av tätningsmetoder det finns. Rapporten har tagits fram genom en litteratur- och fältstudie tillsammans med möten med personer i branschen.
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Mahzari, Pedram. "Prevention of CO2 leakage from underground storage reservoirs." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3152.
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Ye, Xin. "Side Channel Leakage Analysis - Detection, Exploitation and Quantification." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/47.
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Nearly twenty years ago the discovery of side channel attacks has warned the world that security is more than just a mathematical problem. Serious considerations need to be placed on the implementation and its physical media. Nowadays the ever-growing ubiquitous computing calls for in-pace development of security solutions. Although the physical security has attracted increasing public attention, side channel security remains as a problem that is far from being completely solved. An important problem is how much expertise is required by a side channel adversary. The essential interest is to explore whether detailed knowledge about implementation and leakage model are indispensable for a successful side channel attack. If such knowledge is not a prerequisite, attacks can be mounted by even inexperienced adversaries. Hence the threat from physical observables may be underestimated. Another urgent problem is how to secure a cryptographic system in the exposure of unavoidable leakage. Although many countermeasures have been developed, their effectiveness pends empirical verification and the side channel security needs to be evaluated systematically. The research in this dissertation focuses on two topics, leakage-model independent side channel analysis and security evaluation, which are described from three perspectives: leakage detection, exploitation and quantification. To free side channel analysis from the complicated procedure of leakage modeling, an observation to observation comparison approach is proposed. Several attacks presented in this work follow this approach. They exhibit efficient leakage detection and exploitation under various leakage models and implementations. More importantly, this achievement no longer relies on or even requires precise leakage modeling. For the security evaluation, a weak maximum likelihood approach is proposed. It provides a quantification of the loss of full key security due to the presence of side channel leakage. A constructive algorithm is developed following this approach. The algorithm can be used by security lab to measure the leakage resilience. It can also be used by a side channel adversary to determine whether limited side channel information suffices the full key recovery at affordable expense.
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Kang, Eugene K. (Eugene Kim) 1976. "Control of tip-leakage flows using periodic excitation." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/80620.
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