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An enhancement of authentication and energy efficient clustering protocol for wireless sensor network / Ahmed Abdulhadi Jasim
No full textClustering is one of the popular techniques for Wireless Sensor Networks (WSNs) topology management. In each cluster, a leader is selected referred to as cluster head while the rest of the nodes in a cluster are referred to as cluster members. Clustering has been proven to be the most efficient approach in WSN. However, to realize the full benefit of clustering proper authentication and energy efficiency are needed to provide control to the WSN resources and prolonged network lifetime. Two of the main issues in implementing WSN clustering protocol are security issues related to authentication and energy efficiency issues. Therefore, in the first part of this thesis, the focus is given on how to overcome authentication and energy issues due to the problem of the security key and key length sharing at the base station. This can be done by enhancing the authentication of the Media Access Control (MAC) address and by utilizing the distance information and timestamp to detect attacks and reduces energy consumption, using a protocol called Secure and Energy-Efficient Data Aggregation method in clustering based on access control model (SEEDA). The proposed SEEDA protocol enhances the MAC address by utilizing a secret key and random timestamp in the verification process. The base station nodes also utilize the distance and timestamp between nodes to avoid delay in the network. The performance of the proposed SEEDA protocol is compared with SDA, SDAT, SDALFA, EESSDA, SDAACA, and EESDA, which is a widely used clustering protocol in the area of authentication. The simulation results show that the proposed SEEDA protocol outperforms the existing scheme with a 98.84% malicious nodes detection rate, 3.04 joules for energy consumption, the maximum delay of 0.038 seconds, and the resilient time of 0.054, 0.075 seconds with 8%,16% of malicious nodes affecting the network. Apart from looking at the authentication and energy issues, this thesis also focuses on another important energy efficiency issue, which is the hot spots problem. In the WSNs environment, the sensor nodes closer to the base station nodes will take on more forwarding tasks. This will result in a massive overhead of the sensor nodes, and these nodes will run out of power sooner than the others. It causes a breakdown of the nodes and a loss of communication between sensor nodes; this breakdown is called the hot spots problem. Therefore, in the second part of this thesis, the focus is given on how to reduce the hot spots problem and balance the energy consumption among nodes. This can be done by utilizing an unequal clustering in the WSNs is able to reduce the hot spots problem, using a protocol called Energy-Efficient Unequal Clustering protocol based on a Balanced energy method (EEUCB). The proposed EEUCB protocol utilizes an unequal clustering mechanism based on the competition radius, double cluster head selection that reduces the energy consumption of head nodes in the clusters are proposed, applied the sleep and awake mechanism, and the base station calculates the distance based on the closest and farthest nodes and divides this distance into four layers as opposed to depends only on the residual energy of sensor nodes and the distance from all the sensor nodes to the base station node for calculating the competition radius in the prior methods, and also to enhance the data transmission process between sensor nodes and cluster head nodes in the network. EEUCB is compared with UDCH, EEFUC, FLEACH, and LEACH by performing various simulations. The simulation results show that the proposed EEUCB clustering protocol has achieved 13.06%, 14.7%, 19.75%, and 57.75% lifetime improvements against LEACH, EEFUC, FLEACH, and UDCH, respectively
Priority based multi-stage laxity-aware workload distribution for collaborative vehicular edge computing / Zeseya Sharmin
No full textTechnological developments have made it possible for smart machines to access groundbreaking applications. The backend cloud servers are unreliable because of the resultant overhead network to cope with increasing processing requirements. This is usually minimized by the use of edge positions to satisfy the growing demands for computation. A significant function is to maximize productivity and reduce the volume of data transferred into the cloud for fog collection, analysis and storage. Edge locations have commonly been aimed at promoting latency related solutions for end-users. However, resource-restricted regions are frequently flooded by many ongoing demands, whereas the output of delay sensing systems is difficult to sustain at the lowest end-to-end delay. To provide the quality of services (QoS) to resource-limited end-user using computing resources within the data transmission range and to handle the imbalanced workloads because of the traffic density the micro-level fog unit has formed a fog federation in a network that uses underutilized resources to provide service efficiency and achieved energy reduction through this technique by comparing with the traditional non-federated model where multi-access edge computing is used to process data between fog node and the end-users. Most modern innovative vehicular services are delay-sensitive and computationally complex. They pose challenging obstacles for vehicular networks since vehicles are resource stricken with limited computing and storage capacity. Earlier attempts using edge servers get choked up with increasing vehicular traffic. Moreover, workload balancing at available resources, especially there is limited support for priority tasks. In this paper, we propose a collaborative fog computing system to improve balanced fog resource utilization by offloading tasks across the fog federation. The participating fog nodes implement a workload-based offloading decision model, enabling collaboration and suitable fog node selection within the collaborative environment. Furthermore, the system implements a priority-aware multi-queue task scheduling to provide high service throughput. The simulation results demonstrate improved performance for the proposed collaborative fog computing system in terms of queuing delay, delay rate, number of task offloading, and pending tasks
Hybrid integration towards single-chip brillouin devices / Lai Choon Kong
No full textOn-chip RF signal processing and generation via the stimulated Brillouin scattering (SBS) process have become significant research topics in the past few years due to their unmatched capabilities. Having access to gigahertz repetition rates can enable applications such as RF filters, true time delay (TTD), optoelectronic oscillator (OEO), and optical frequency comb (OFC). Chalcogenide glass, and in particularly Arsenic Trisulfide, has become a popular optical material due to its high optical nonlinearity, near ideal acoustic properties for SBS applications. However, monolithic integration cannot be realised using chalcogenide glass due to its high propagation loss, fibre-to-chip coupling loss, and facet reflection. In this thesis, a hybrid waveguide solution will be proposed by leveraging the vertical taper technology via shadow mask deposition. By overlaying the Brillouin active waveguide on a low loss versatile germanosilicate platform, a variety of linear functionalities such as ring resonators, Bragg gratings and tolerant couplers can be incorporated in a fully integrated Brillouin based device. The optimisation process for flame hydrolysis deposition of the 3% index contrast germanosilicate and its facet machining have been rigorously studied in this work. This has led to an experimental propagation loss and fibre-to-chip coupling loss of <0.1 dB/cm and 0.2 dB/facet when coupled with a Nufern UHNA-3 fibre. Further, whilst the 0.7 × 10-9 m/W Brillouin gain coefficient obtained in the proposed hybrid As2S3-Ge:SiO2 waveguide is identical to the previous monolithic As2S3 counterpart, the hybrid structure offers an extra 20 dB reduction in the pump back reflection, making it so suitable to be implemented in the backward SBS applications
Thermal performance analysis of flat-plate solar collector by using carbon and metal based nanofluids / Naveed Akram
No full textThermal performance analysis of flat-plate solar collector by using carbon and metal based nanofluids were carried out in this study. Different nanomaterials such as, graphene nanoplatelets (GNPs) with SSAs of 750 m2/g, iron nanoparticles (Fe3O4) (< 9 nm), zinc oxide (ZnO) (< 50 nm), and silicon dioxide (SiO2) (10-20 nm) based aqueous nanofluids were synthesized at the weight concentrations range of 0.025% to 0.2%. Thermodynamic properties and colloidal stability of the nanofluids were thoroughly investigated. The overall performance of FPSC was analyzed using commercial ANSYS fluent 16.2 and was validated experimentally. Experiments were performed following ASHRAE indoor standard; where the inlet temperatures range of 30 - 50 ᵒC; flow rates of 0.8, 1.2 and 1.6 kg/min; and heat flux intensities of 597, 775 and 988 W/m2 were maintained. In this investigation the nanofluids were synthesized by probe sonication method. The maximum colloidal stability of nanofluid was obtained at 60 min ultrasonication time for the graphene nanoplatelets. Non-covalent functionalization with surfactants enhanced stability but created unnecessary foam. The undesired phenomena were avoided by covalent functionalization of the suspensions such as, clove-treated GNPs (CGNPs) and polyethylene glycol-treated Fe3O4. Successful functionalization was later confirmed through different characterization methods. Present investigation results revealed that the success of suspension stability was dependent on nanomaterial and weight concentrations, in the present case it was observed the suspension weight concentration of 0.9543 for PEG- Fe3O4, at 0.1wt.% nanofluid concentration. Thermophysical properties of the synthesized nanofluids were enhanced. The temperature was directly proportional to the thermal conductivity and indirectly proportional to the viscosity, density, and specific heat of the nanofluids. The noticeable increase in thermal conductivity was up to 25.68% at 0.1wt.% CGNPs. The measured thermal conductivity of CGNPs showed good agreement with the model of Lu-Li. The maximum increment in viscosity of nanofluid was 24.05% for SiO2, followed by 22.4% and 12% for PEG- Fe3O4 and CGNPs. The measured viscosity is well-matched with the Batchelor and Einstein model with a maximum deviation of 6.1%. The deviation in measured density is up to 0.08% higher and well-matched with Pak & Cho equation, while the specific heat deviation reduced up to 1.54% and showed good agreement with Xuan & Roetzel equation. The efficiency of FPSC is directly proportional to the heat flux intensity and flow rate and inversely proportional to the inlet fluid temperature. As the concentration of nanoparticles increased, the experimental values of AP and TW were decreased about 8.07% and 8.23%, respectively, in comparison with the water data, while efficiency was increased up to 18.2% at 0.1 wt.% CGNPs. Experimental results of efficiency, AP, and TW for water were well matched with the ANSYS Fluent results with the highest differences of 3.22%, 2.21%, and 2.48%, respectively. On the other hand, for CGNPs nanofluid, the maximum differences were 8.20%, 2.70%, and 1.88% respectively. The performance index was higher than one for all the nanofluids and increased up to 1.142 for 0.1wt.% CGNPs nanofluid. All the nanofluids have higher positive effectiveness effects than the negative pressure drops effects. Consequently, the investigated nanofluids can be used to enhance the thermal efficiency of FPSCs and at 0.1wt.% the CGNPs nanofluid provided the highest performance which could be considered superior to others
Implementation of fuel saving techniques among airliners in Malaysia / Deenadayalini Retnam
No full textFuel Management is a concept that has been ever evolving till date due to two main
factors; the volatile fuel market which has increasing prices from time to time causing a
significant negative impact on the aviation industries and also the contribution of harmful
gases to the environment. These factors make it essential for the fuel management
divisions to implement effective fuel saving techniques in order to reduce fuel usage. Past
research only acknowledges on the fuel saving techniques around the world, but the
studies did not provide empirical evidence on how efficient are those fuel saving
techniques being practiced by the Malaysian Aviation Industry. This research focused on
investigating the different fuel saving techniques implemented among airliners in
Malaysia in order to overcome the negative impacts of fuel consumption because airlines
are frequently under financial strain during times of crisis, therefore need to devise some
ways to come through. The methodology applied to analyze the various techniques that
implement among airliners in Malaysia includes an analysis of how these techniques
proved to be successful was also carried out and this was mainly focused to Malaysia
Airlines. The method used to gain information that is based on survey questionnaires
distributed into two main divisions; the flight operations and the planning operations
which are believed to play the most important role in flight planning and fuel
optimization. The survey involved Air Asia, Air Asia X, Malindo Air, Firefly, Malaysia
Airlines, Raya Airways, MASwings and a renowned MRO Sepang Aircraft Engineering
(SAE). The result shows majority airlines in Malaysia proven to have most of the fuel
saving techniques as stated in survey questionnaire. Some of these measures successfully
support the result of previous research done on the evidence of the performance of
Malaysia Airlines. However, there are few techniques couldn't get to implement due to cost, incapability and time limitation. Therefore, further improvements needed by
recommending new technique or enhancement of a current technique for fuel saving
Flow characteristic investigation of a novel power-augmented water kinetic turbine for energy capturing from river / Christopher Clement Rusli
No full textFossil fuel power plants still dominate world electricity generation. 38% of the world’s
electricity generation is coal, and another 23% is natural gas. Fossil power plants impact
a lot on pollutant emissions. Therefore, renewable energy needs to be developed to reduce
this effect. Renewable energy uses an available energy source that automatically
recharges naturally—the energy sources such as sun, wind, water, Earth’s heat, and
plants. One of the water sources available is a river, which can generate electricity in rural
areas. The hydrokinetic turbine is used to capture the available energy from the river. A
lot of studies show the availability to capture water energy using a kinetic turbine.
However, the efficiency of the hydrokinetic turbine is relatively low. Thus, this study is
carried out to observed the augmentation design for the hydrokinetic turbine. The vertical axis turbine two-blade with NACA0021 airfoil profile will be used for this study. The
augmentation observed will be a NACA0015 profile with a chord length of 2000 mm and
connected with spline tools to create the augmentation profile. Both analytical and
numerical methods will be used in this study. The analytical approach is used to
approximate the performance of the blade used for the turbine. The numerical method
will be used to observed the flow characteristic and the efficiency of the augmentation
profile. Three different pitch angles for the augmentation profile—6°, 10°, and 15° are
used to enhance the hydrokinetic turbine’s performance. The hydrokinetic turbine has a
baseline performance of 0.397 at TSR is equal to 2.58. The augmentation profile achieved
a 77.33% performance improvement with a power coefficient value of 0.704 at TSR is
equal to 3.0. The positioning of the turbine is also observed because it affects the
performance as well. This study finds that the positioning of the turbine can slightly improve the performance and worsen the performance too. The power coefficient reaches
the highest of 0.712 when the turbine slightly moved from the initial position. In
conclusion, this study proves the significant impact of the augmentation implemented in
the vertical-axis hydrokinetic turbine. The improvement of power coefficient reaches as
high as 79.34% compared to the bare turbine
Demographic change, education and economic growth in Middle Eastern countries / Abdullah Abdulaziz Abdullah Bawazir
No full textThe demographic change-economic growth relationship has been extensively researched for several decades. This has become the dominant paradigm in the field of population and development, and an advocacy tool for highlighting the benefits of age structure change. In the Middle Eastern nations, the proportion of working-age population demonstrated a remarkable change in the population structure over several decades with potential implications on the economy. Additionally, the influence of human capital on economic growth proved crucial as it has been seen as the engine of economic growth. This study aimed to investigate the impact of demographic change and education on economic growth in 10 Middle Eastern countries between 1996 and 2018. For this purpose, the study utilized three alternative models of static panel data comprising of the pooled ordinary least squares, random effects, and fixed effects. This study outlined demographic changes more extensively than most works of literature using the internal demographic compositions of the working-age population with age and gender as measures of demographic change. The results revealed that the demographic changes reflected by the internal demographic composition of the working-age population (young, middle-aged, and senior workers) significantly and positively contributed to economic growth. Moreover, two distinct measures for population ageing were employed, namely, population aged 65 and above and the old-age dependency ratio. Resultantly, the aforementioned age range and dependency ratio positively influenced economic growth. As such, the senior population was not a matter of concern for the Middle East. The mechanisms through which the positive effect can take place are savings behaviour and human capital accumulation of the individuals, in which case, the elderly individuals are viewed as a source of skilled talents who are able to work for an extended duration of time. This will enable countries to be recipients of the optimal value of older workers who have the tendency to possess extensive experience and knowledge. The educational level-economic growth relationship was also investigated using gender-disaggregated data, thus highlighting that education positively contributed to Middle Eastern economic growth. Specifically, tertiary education contributed more to economic growth compared to other education levels. This is particularly significant as the importance of tertiary education is undeniable in terms of offering knowledge and generating highly skilled workers. In terms of gender, the results showed that both male and female education had a significant impact on economic growth; however, the female education levels contributed more to economic growth than the male education levels. Furthermore, investigation on the role of education and fertility indicated that these determinants were the most vital drivers of female labour force participation. In this vein, the increase in female education and subsequent decrease in fertility rates potentially resulted to increase female labour participation in the region. Hence, more efforts should be made to encourage women’s active engagement in the labour market for the achievement of economic benefits. Overall, the Middle East region required demographic and economic policies that promote active engagement in the labour market to enhance productivity and achieve a high-income economy. Educational policies were also needed to prioritise human capital development
Determinants and informational value of sovereign credit ratings / Lim Kok Tiong
No full textThe sovereign credit ratings (SCRs) issued by Moody’s, S&P, and Fitch in the form of
alpha-numeric (i.e., Aaa, Aa1, Aa2, Aa3, etc.) and alpha-symbol (i.e., AAA, AA+, AA,
AA-, etc.) are essential for rated countries to gain access to funds without the
conditionality on collateral placement or the commitment on austerity measures. The SCR
notches which are proxies of creditworthiness ranking on rated countries have been an
integral part and a key determinant of the cost of borrowing. However, the prolonged
implementation of zero-bound-policy-rate (ZBPR) and quantitative easing programme
(QEP) raises the query on SCRs relevancy. This thesis examines the determination of
SCRs and SCRs information value on sovereign bond yields (SBYs) and sovereign credit
default swap spreads (SCDSs) of investment-grade rated countries. A sample of 32
investment grade multi-rated countries with quarterly and annual observations spanning
from 2008 to 2017, when ZBPR and QEP were in effect, are used in this study. The
empirical results show no evidence that the determination of SCRs was compromised
when ZBPR and QEP were in effect. The SCRs determinants consist of GDP Growth,
GDP Per Capita, Government Effectiveness Index, Inflation, Fiscal Balance, Debt to
GDP, Reserve to GDP, and Financial Development Index continue to predict SCRs with
high accuracy. However, the empirical results show that the SCRs information value was
indeed disregarded, and rendered irrelevant on debts price discovery. The empirical
estimates show that SCRs, irrespective of the credit rating agencies, are insignificant in
the pricing of SBYs since 2008. The empirical estimates show that SCRs are also
insignificant in pricing the SCDSs, but only from 2012 onwards. Since the SCRs is an
essential enabler on the transmission of funds among countries and private sectors, the results showing that SCRs information value was disregarded in SBYs and SCDSs pricing
present broad and cascading implication on credit risk pricing. Therefore, the findings on
SCRs information value being irrelevant when ZBPR and QEP were in effect provide an
important revelation. This revelation must be assessed and mitigated by the credit rating
agencies, policymakers, and institutional investors
Experiences of nurse educators in Malaysia regarding problem based learning / Umadevi Alasingam
No full textIn 2010, declining standards of nursing care in Malaysia triggered immense concern. This erosion was traced to inadequate teacher-centric nurse instruction in nursing schools. The Malaysian government proposed that Problem-based learning, a student-led instruction method, be utilized henceforth. This study aims to investigate the experiences of nurse-educators regarding Problem-based learning presuming that successful implementation of Problem-based learning method hinged heavily on the role, capabilities and attitude of nurse-educators regarding this divergent learning method. A study was conducted among five nurse-educators with long experiences in using this method. They were interviewed using open-ended questions. Interview data obtained was analyzed using N-Vivo-12 analytical software. The findings indicated that the nurse-educators had limited knowledge of Problem-based learning techniques, lacked adequate training in facilitating and exhibited insufficient conviction in utilizing Problem-based learning in its entirety in their teaching functions. The findings revealed that these nurse-educators complemented Problem Based learning with lectures and notes. A related finding was the poor support extended by management to these nurse-educators and the lack of monitoring of implementation of Problem-based learning. The significance of this study lies in the expose on the educators’ experiences adding to the limited research and information hitherto available regarding Problem-based learning- educator perceptions. The findings point towards educator preference for mixed-mode instruction rather than sole reliance on Problem-based learning
Interaction of scientist-teacher-students in problem-project based learning / Cheong Boon Yau
No full textInviting scientist into inquiry-based learning has become the puzzles to be addressed in science education. However, finite mechanism on how tripartite interaction between scientist, teacher and students takes place is yet to be explored. This study sheds light on interaction of scientist-teacher-students collaboration in problem-project based learning (STSC-PPbl) in authentic research setting. This basic qualitative-exploratory study employed participant observation protocol triangulated by reflective journals written by students to collect the data of interaction between one scientist, one teacher and four upper secondary school students in this study. The data were analysed qualitatively using Balesian Interaction Process Analysis (IPA) coupled with adapted Transcript Analysis Tool and the structural elements of interaction were analysed using Structural Exchange Pattern (SEP) analysis based on quantification of qualitative codes. SEP analysis showed that students could have direct interaction with scientist. The findings from IPA revealed variety of interaction functions of scientist, teacher, and students from orientation, control, evaluation and independency in neutral task areas; decision, integration and tension management in socioemotional areas during variety modes of interactions. All these interactions reflected the role of scientist as scientific practice expertise, and teacher as education practitioner and facilitator associated with neutral task area functions as “one teaches, one assists and facilitates” co-teaching duo. The findings from socioemotional areas revealed that students showed remarkable intensity of negative tension management functions due to problems faced during experimentation and it can be resolved by tension release and integration functions executed by both scientist and teacher. This study suggests that educators can view and make tension aroused within students as the trigger and driver of science learning facilitation through employing appropriate interactive strategies based on the findings from this study to make such collaboration meaningful and successful, devising interactive strategy implementation for school-industry partnership from science education perspective