3,040 research outputs found

    Demand for Money in the Asian Countries: A Systems GMM Panel Data Approach and Structural Breaks

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    A systems GMM method is used to estimate the demand for money (M1) for a panel of 11 Asian countries from 1970 to 2007. This method has advantages of which the most important one is its ability to minimise small sample bias with persistence in the variables. This system GMM method of Blundell and Bond (1998) simultaneously estimates specifications with the levels and first differences specifications of the variables. We test for structural stability of the estimated function with a recently developed test, for this approach, by Mancini-Griffoli and Pauwels (2006). Our results show that there is a well defined demand for money for these countries and there are no structural breaks.Systems GMM, Blundell and Bond, Mancini-Griffoli and Pauwels, Asian Countries and Demand for Money and Structural Sta

    Post curing of Hansa-3 (VT- HNW) Components

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    This report contains the detads of post curing of Hansa-3 (VT- HNW) all composite airframe components provided byC-CADD, carried out using an in-house designed and fabricated large hot air oven (17mts x 2.0mts x 2.0mts). It details an optimum post cure cycle implemented, the temperature accuracy's, the various innovative approaches adapted to ensure the safety of the full scale components undergoing post cure in the oven. All the Hansa-3 (VT-HNW) airframe composite components post cured as per the standard optimum post cure cycle and the oven temperature monitored throughout around f 3degree C to ensure uniform post curing of components

    Analysis and Mitigation of Recent Attacks on Mobile Communication Backend

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    2014 aasta viimases kvartalis demonstreeriti mitmeid edukaid rünnakuid mobiilsidevõrkude vastu. Need baseerusid ühe peamise signaaliprotokolli, SS7 väärkasutamisel. Ründajatel õnnestus positsioneerida mobiilseadmete kasutajaid ja kuulata pealt nii kõnesid kui ka tekstisõnumeid. Ajal mil enamik viimase aja ründeid paljastavad nõrkusi lõppkasutajate seadmete tarkvaras, paljastavad need hiljutised rünnakud põhivõrkude endi haavatavust. Teadaolevalt on mobiilsete telekommunikatsioonivõrkude tööstuses raskusi haavatavuste õigeaegsel avastamisel ja nende mõistmisel. Käesolev töö on osa püüdlusest neid probleeme mõista. Töö annab põhjaliku ülevaate ja analüüsib teadaolevaid rünnakuid ning toob välja võimalikud lahendused. Rünnakud võivad olla väga suurte tagajärgedega, kuna vaatamata SS7 protokolli vanusele, jääb see siiski peamiseks signaaliprotokolliks mobiilsidevõrkudes veel pikaks ajaks. Uurimustöö analüüs ja tulemused aitavad mobiilsideoperaatoritel hinnata oma võrkude haavatavust ning teha paremaid investeeringuid oma taristu turvalisusele. Tulemused esitletakse mobiilsideoperaatoritele, võrguseadmete müüjatele ning 3GPP standardi organisatsioonile.In the last quarter of 2014, several successful attacks against mobile networks were demonstrated. They are based on misuse of one of the key signaling protocol, SS7, which is extensively used in the mobile communication backend for signaling tasks such as call and mobility management. The attackers were able to locate the mobile users and intercept voice calls and text messages. While most attacks in the public eye are those which exploits weaknesses in the end-device software or radio access links, these recently demonstrated vulnerabilities exploit weaknesses of the mobile core networks themselves. Understandably, there is a scramble in the mobile telecommunications industry to understand the attacks and the underlying vulnerabilities. This thesis is part of that effort. This thesis presents a broad and thorough overview and analysis of the known attacks against mobile network signaling protocols and the possible mitigation strategies. The attacks are presented in a uniform way, in relation to the mobile network protocol standards and signaling scenarios. Moreover, this thesis also presents a new attack that enables a malicious party with access to the signaling network to remove lost or stolen phones from the blacklist that is intended to prevent their use. Both the known and new attacks have been confirmed by implementing them in a controlled test environment. The attacks are serious because SS7, despite its age, remains the main signaling protocol in the mobile networks and will still long be required for interoperability and background compatibility in international roaming. Moreover, the number of entities with access to the core network, and hence the number of potential attackers, has increased significantly because of changes in regulation and opening of the networks to competition. The analysis and new results of this thesis will help mobile network providers and operators to assess the vulnerabilities in their infrastructure and to make security-aware decisions regarding their future investments and standardization. The results will be presented to the operators, network-equipment vendors, and to the 3GPP standards body

    Process Control and Efficiency Improvements of Industrial Boiler

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    The efficiency of improvement of the boiler is identified as the main priority of this project. This can be done by studying and suggest the ways to enhance the process control of the steam generating system and its instrumentation. Boiler with the closest specifications recommended is taken as the case study. Therefore, the suggested recommendation can be assumed as have been implemented. The recommendation is assumed to be implemented and efficiency calculations using mathematical programming approach has been done. The first phase of the project is the study on boiler in terms fuel characteristics, firing system and combustion control to enhance the efficiency calculation at the later stage. The suggestions on ways to improve have led to the installment of Air preheater (APH) unit at a small capacity refinery boiler. Energy savings calculation has been done and resulting output was satisfactory. Therefore, the first phase of the study has been successful. The second phase of the project is the mathematical programming approach to determine the efficiency of the boiler by assuming suggested improvements in fuel combustion has be implemented. The MATLAB program takes into account of the variation in gas constituents in fuel and gives the most accurate heating values and flue gas analysis based on the theoretical combustion. The efficiency of the boiler is determined to be above satisfactory level thus making the second phase of the project a major success

    Cyber-physical security of a chemical plant

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    The increasing number of cyber attacks on industries demands immediate attention for providing more secure mechanisms to safeguard industries and minimize risks. A supervisory control and data acquisition (SCADA) system employing the distributed networks of sensors and actuators that interact with the physical environment is vulnerable to attacks that target the interface between the cyber and physical subsystems. These cyber attacks are typically malicious actions that cause undesired results in the cyber physical world, for example, the Stuxnet attack that targeted Iran\u27s nuclear centrifuges. An attack that hijacks the sensors in an attempt to provide false readings to the controller can be used to feign normal system operation for the control system, while the attacker can hijack the actuators to send the system beyond its safety range. Cyber physical systems (CPS) being used in industries such as oil and gas, chemical process plants and the like are termed Industrial Control Systems (ICS). Control system security is aimed at preventing intentional or unintentional interference with the proper operation of ICS. This thesis proposes a process-aware approach with the use of invariant equations based on the physical and chemical properties of the process and a Multiple Security Domain Nondeducibility (MSDND) framework to detect when a sensor signal is being maliciously manipulated. We have taken a benzene production plant as case study to illustrate our approach and its effectiveness in determining the state of the system. A system without any MSDND secure information flows between the CPS and cyber monitors has fewer weaknesses that can be exploited --Abstract, page iii

    Design of Two Phase Sinusoidal Power Clock using Adiabatic Switching

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    "Adiabatic" is a term of Greek origin that has spent most of its history associated with classical thermodynamics. It refers to a system in which a transition occurs without energy usually in the form of heat being either lost to or gained from the system. In the context of electronic systems, rather than heat, electronic charge is preserved. Thus, an ideal adiabatic circuit would operate without the loss or gain of electronic charge. Hence, in this work the two phase sinusoidal power clock is designed using Adiabatic switching

    Heat transfer in combined convective magnetohydrodynamic motion of nanofluid holding different shapes of nanoparticles in a channel under the influence of heat source

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    Heat transfer in mixed convection unsteady MHD flow of an incompressible nanofluid in a channel under the influence of heat source is studied. The channel with non-uniform walls temperature is taken in a perpendicular direction with a transverse magnetic field. Based on the substantial boundary conditions, three different flow conditions are examined. The problem is formed in PDEs with substantial boundary conditions. Four different forms of nanoparticles of identical volume fraction are employed in traditional base fluid water (H2O). Solutions for momentum and energy are attained by the perturbation method and examined graphically in different graphs. It is established that viscosity and thermal conductivity are the mainly well-known variables accountable for different results of velocity and temperature. It is also found that increasing heat source leads to an increase in nanofluid velocity and temperature and nano-size particles instance platelet and blade shapes have lesser momentum as related to brick and cylinder size of nanoparticles

    Heat transfer in combined convective magnetohydrodynamic motion of nanofluid holding different shapes of nanoparticles in a channel under the influence of heat source

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    87-98Heat transfer in mixed convection unsteady MHD flow of an incompressible nanofluid in a channel under the influence of heat source is studied. The channel with non-uniform walls temperature is taken in a perpendicular direction with a transverse magnetic field. Based on the substantial boundary conditions, three different flow conditions are examined. The problem is formed in PDEs with substantial boundary conditions. Four different forms of nanoparticles of identical volume fraction are employed in traditional base fluid water (H2O). Solutions for momentum and energy are attained by the perturbation method and examined graphically in different graphs. It is established that viscosity and thermal conductivity are the mainly well-known variables accountable for different results of velocity and temperature. It is also found that increasing heat source leads to an increase in nanofluid velocity and temperature and nano-size particles instance platelet and blade shapes have lesser momentum as related to brick and cylinder size of nanoparticles
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