Engineering and Technology

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A Literature Review on Sampling Techniques in Semiconductor Manufacturing
(IEEE Transactions on Semiconductor Manufacturing, 2013) Nduhura-Munga, Justin; Rodriguez-Verjan, Gloria; Dauz ´ ere-P ` er´ es, Stephane; Yugma, Claude; Vialletelle, Philippe; Pinaton, Jacques
This paper reviews sampling techniques for inspection in semiconductor manufacturing. We discuss the strengths and weaknesses of techniques developed in the last last 20 years for excursion monitoring (when a process or machine falls out of specifications) and control. Sampling techniques are classified into three main groups: static, adaptive, and dynamic. For each group, a classification is performed per year, approach, and industrial deployment. A comparison between the groups indicates a complementarity strongly linked to the semiconductor environment. Benefits and drawbacks of each group are discussed, showing significant improvements from static to dynamic through adaptive sampling techniques. Dynamic sampling seems to be more appropriate for modern semiconductor plants.
The relationship between the Old Case Loads and New Case Loads in Nakivale refugee settlement in Southwestern Uganda
(Journal of Eastern African Studies, 2016)
Forced migration from Rwanda has become a common trend. It has been there since time immemorial and is still continuing at varying magnitudes. Scholarly literature indicate that over 100,000 Rwandan refugees crossed into Uganda and other neighbouring countries of Burundi, Tanzania and Zaire (the present day Democratic Republic of Congo) in early 1960s seeking asylum following violent political and social changes in Rwanda that erupted in 1959. Rwanda was a former colony of Germany before the First World War which later came under the Belgian administration. It is comprised of three ethnic groups, Tutsi, Hutu and Twa, with the Hutu taking 85%, followed by the Tutsi at 14% and the Twa at 1% of the total population. Interestingly, they all speak the same language; Ikinyarwanda. Prior to colonization, the Tutsi, although smaller in number, were the ruling ethnic group over the majority Hutu. In 1959, as Rwanda was warming up to attain independence, tensions started erupting between the Tutsi and Hutu over who should rule the new country. It is believed that although the Tutsi were few in numbers, they were more elite and intelligent compared to the majority Hutu. The Hutu, having been mistreated and under looked during the reign of Tutsi, they were determined to supersede them this time round. As the tensions heightened, many Tutsi were killed and the remnants fled to neighbouring countries. To some scholars, this was blamed on the poor management by the Belgians who are believed to have dragged their feet at the beginning and later moved too fast without proper preparation for decolonization of the local communities. The Belgian colonial masters put in place identity cards that classified individual Rwandans as either Hutu or Tutsi which meant permanent racialised divisions in favour of the ruling Tutsi by then1.
ADSMS: Anomaly Detection Scheme for Mitigating Sink Hole Attack in Wireless Sensor Network
(IEEE, 2017) Yasin, N. Mohammaed; Balaji, N.; Sambasivam, G.; Basha, M. S. Saleem; Sujatha, P.
In past years, mobile ad hoc networks (MANETs) widespread use in many applications, including for some mission-critical applications, and has become one of the major concerns such as security MANETs. MANETs due to some unique characteristics, prevention methods are not alone enough to protect them need; Therefore, the detection is possible for an attacker to breach system security, such as the need to add another before. In general, traditional wireless networks, intrusion detection techniques are not well suited for MANETs. In this case, to protect it from attacks MANETs is important to develop more efficient methods of intrusion detection. With improvements in technology and cutting hardware costs, we MANETs expanding into industrial applications are also witnessing a current trend. To cope with such a trend and we believe strongly that it was important for its potential security issues. In this paper, we propose new intrusion detection and specially designed MANETs Improved Acceptance acknowledgment (EAACK) to activate the digital signature system. Compared to contemporary approaches, while not greatly affect network shows EAACK certain conditions demonstrates the high detection rates of malicious behaviour
A Normalized Approach for Service Discovery
(Procedia Computer Science, 2015) Sambasivam, G.; Ravisankar, V.; Vengattaraman, T.; Baskaran, R.; Dhavachelvan, P.
In today’s world web services are the known perception to all the users who uses the internet. The Web Service process involves service discovery, selection and ranking. Discovery is the process of matchmaking of user query with advertisements in the repository. Our motivation is to develop a model for web service discovery with the combined approach of service selection and ranking. In this paper, we have proposed a technique for web service discovery process, combining the keyword search and semantic search and ranking the services. The implementation results show that the proposed model performs better for the web service discovery process.
Mira: an Application Containerization Pipeline for Small Software Development Teams in Low Resource Settings
(Development Engineering, 2022) Mwotil, Alex; Bainomugisha, Engineer; Araka, Stephen G.M.
Cloud native applications leverage Development and Operation (DevOps), microservice architectures and containerisation for primarily availability, resilience and scalability reasons. Small developer teams in low resource settings have unique DevOps needs and harnessing its principles and practices is technically challenging and distinctly difficult in these contexts. We conducted a survey with professional developers, students and researchers situated and working in a low resource setting and the results indicate that these principles and practices are relatively new. In application containerisation, an operating system virtualisation method that can significantly optimize the use of computing resources, the respondents indicated challenges in the process steps. Particularly, small developer teams in low resource settings require custom tools and abstractions for software development and delivery automation. Informed by the developer needs, we designed and developed a custom automated containerisation pipeline, mira, for a managed cloud native platform situated in a low-resource setting. We validate mira against 6 major application frameworks, tools and/or languages and successful deployment of the resultant applications onto a cloud native platform.
Hydraulic conductivity predictive model of RHA-ameliorated laterite for solving landfill liner leachate, soil and water contamination and carbon emission problems
(International Journal of Low-Carbon Technologies, 2022) Onyelowe, Kennedy C.; Ebid, Ahmed M; Baldovino, Jair de Jesús Arrieta; Onyia, Michael E.
The environment is seriously being affected by the leachate release at the unconstructed and badly constructed waste containment or landfill facilities around the globe. The worst hit is the developing world where there is little or totally no waste management system and facilities to receive waste released into the atmosphere. This research work is focused on the leachate drain into the soil and the underground water from landfills, which toxicifies both the soil and the water. Also, the construction of the liner or barrier with cement poses serious threat to the environment due to oxides of carbon release and this research also took this into account by replacing the utilization of cement with rice husk ash (RHA), which has proven to have the potentials of replacing cement as a supplementary binder. Laboratory tests were conducted to determine the hydraulic conductivity (K) of lateritic soil (LS) ameliorated with different dosages of RHA. Other hydromechanical properties of the treated blend were studied and multiple data were generated for the artificial neural network (ANN) back-propagation (-BP), genetic algorithm (GA) and gradual reducing gradient (GRG), genetic programming (GP) and evolutionary polynomial regression (EPR) prediction exercises. Results show that the LS was a poorly graded A-2 sandy silt soil, which was subjected to three different compaction energies with the minimum of the British standard light (BSL) and derived k of 6.95E-10, 50.75E-10 and 32.33E-10 for BSL, west African standard and British standard heavy, respectively. The RHA addition improved the studied properties of the ameliorated LS. Out of the five models, the ANN-GRG outclassed others with a performance of 99% with minimal error compared with the rest. Potentially, this research has shown that RHA with a pozzolanic chemical moduli of 81.47% can replace cement in the construction of ecofriendly and more efficient landfills and waste containemnt barriers to save the soil and the underground water as well as the environment from leachate contamination and carbon emissions.
Energy Efficiency and Spectral Efficiency Trade-off of a Novel Interference Avoidance Approach for LTE-Femtocell Networks
(IEEE., 2012) Wang, Siyi; Turyagyenda, Charles; O’Farrell, Tim
The trade-off between energy efficiency and downlink spectral efficiency for LTE-femtocells can be significantly balanced by a novel interference management technique in the presence of the interference from the co-channel outdoor micro-cell and the neighbouring femtocell access points. The simulation results have been demonstrated to be meaningful in the context of considering capacity saturation of realistic modulation and coding schemes rather than theoretical Shannon's equation. The paper shows that the radio-head and operational improvement of up to 12% and 3% can be achieved. Moreover, it has been shown that the improvement does not significantly degrade the user's data rate and the proposed scheme can be implemented in unplanned self- organising networks.
Security Analysis of Mobile Edge Computing in Virtualized Small Cell Networks
(Springer International Publishing., 2016) Vassilakis, Vassilios; Chochliouros, Ioannis P.; Spiliopoulou, Anastasia S.; Turyagyenda, Charles; Dardamanis, Athanassios
Based upon the context of Mobile Edge Computing (MEC) actual research and within the innovative scope of the SESAME EU-funded research project, we propose and assess a framework for security analysis applied in virtualised Small Cell Networks, with the aim of further extending MEC in the broader 5G environment. More specifically, by applying the fundamental concepts of the SESAME original architecture that aims at providing enhanced multi-tenant MEC services through Small Cells coordination and virtualization, we focus on a realistic 5G-oriented scenario enabling the provision of large multi-tenant enterprise services by using MEC. Then we evaluate several security issues by using a formal methodology, known as the Secure Tropos.
Energy Efficiency Comparison of Common Packet Schedulers
(IEEE., 2014) Turyagyenda, C.; Albeiruti, N.; Zak, M.; Al-Begain, K.
This paper presents a characterisation of the energy performance of common and well-known packet schedulers in a multi-cell multi-user UTRAN long-term evolution (LTE) system. First, it was shown that the maximum SINR metric is more energy efficient than the round robin metric for both time and frequency domain packet scheduling. Second, it was shown that frequency domain packet scheduling had a greater impact on the energy efficiency of the system than time domain packet scheduling; i.e. RF Energy Reduction Gains (RF-ERG) ranging from 16% to 49% and 2% to 18% respectively.
Long Term Evolution Downlink Packet Scheduling using A Novel Proportional-Fair-Energy Policy
(IEEE., 2012) Turyagyenda, C.; O'Farrell, T.; Guo, W.
Inter-cell interference (ICI) is a key limiting factor to the general performance of a multi-cell multi-user radio access network. The channel quality of cell edge users is greatly impaired by ICI owing to the fact that cell edge users are furthest away from the their serving base station and closest to the interfering base stations. As a result the Quality of Service (QoS) and energy efficiency of the E-UTRAN is primarily dependant on the cell edge users. Firstly, we propose a new Time Domain Packet Scheduling criterion that endeavours to reduce the variation in the energy performance, of the users, in a temporal sense. The proposed criteria aims to strike a balance between two user prioritisation criteria that result in energy performance at the two extremes of the energy consumption range. The paper shows that this improves the mean energy efficiency of the E-UTRAN. Secondly, we introduce an energy optimisation algorithm to complement the Time Domain Packet Scheduler. The new energy aware packet scheduling criteria is compared against the established throughput based proportional fair scheduler with uniform power allocation and is shown to produce 20% Energy Reduction Gains (ERG) without compromising the spectral efficiency and QoS performance.
SFBC MIMO Energy Efficiency Improvements of Common Packet Schedulers for the Long Term Evolution Downlink
(IEEE., 2011) Turyagyenda, C.; O’Farrell, T.; He, J.; Loskot, P.
It is desirable that energy performance improvement is not realized at the expense of other network performance parameters. This paper investigates the trade off between energy efficiency, spectral efficiency and user QoS performance for a multi-cell multi-user radio access network. Specifically, the energy consumption ratio (ECR) and the spectral efficiency of several common frequency domain packet schedulers in a cellular E- UTRAN downlink are compared for both the SISO transmission mode and the 2×2 Alamouti Space Frequency Block Code (SFBC) MIMO transmission mode. It is well known that the 2×2 SFBC MIMO transmission mode is more spectrally efficient compared to the SISO transmission mode, however, the relationship between energy efficiency and spectral efficiency is undecided. It is shown that, for the E-UTRAN downlink with fixed transmission power, spectral efficiency improvement results into energy efficiency improvement. The effect of SFBC MIMO versus SISO on the user QoS performance is also studied.
Performance Security Trade-off of Network Intrusion Detection and Prevention Systems
(UK Performance Engineering Workshop and Cyber Security Workshop, 2016) Munir, Rashid; Ahmed, Botan; Al-Mohannadi, Hamad; Mufti, M. Rafiq; Namanya, Anitta Patience; Awan, Irfan
Security cyber threats are increasing with most companies being overwhelm by the complexity attached to prevention against attacks. Network Intrusion detection and prevention systems (NIDPS) are now a stable in any enterprise network with the purpose of filtering through the network traffic and sniffing for malicious traffic. Given the amount of traffic generated on enterprise networks nowadays, any NIDPS is sure to go through a big number of packets that a need arises for a performance- security trade-off. On any given day, based on the rules used in the NIDPS, the number of alerts it generates are in thousands. This can be quite overwhelming to security analysts who analyse them to understand the cyber threat landscape. Although it is true the more alerts, the higher the probability of detecting malicious traffic, it is also true that alerts require the traffic to go through many rules which can be quite a performance hindrance. This is the paradox plagued by the cyber security community currently. In this paper, we examine 2 scenarios to evaluate the performance security trade-off for the purpose of propose ways of improving the performance while minimising the impact on the security purpose for the NIDPS.
Performance Modelling and Analysis of the Delay Aware Routing Metric in Cognitive Radio Ad Hoc Networks
(IEEE, 2013) Namanya, Anitta Patience; Pagna-Disso, Jules
Cognitive Radio Networks have been proposed to solve the problem of overcrowded unlicensed spectrum by using the cognitive ability built in software radios to utilise the underutilised licensed channel when the licensed users are not using it. Successful results from the research community have led to its application to wireless technologies like Ad Hoc networks due to their extensive advantages. Cognitive Radio Ad Hoc networks are a novel technology that will provide a solution to many communication challenges. This paper investigates the end-to-end performance modelling of a link using quality of service parameters; delay vs. link capacity while considering the factors of spectrum management and node mobility of two nodes in tandem representing a hop in Cognitive Radio Ad Hoc networks. We modelled spectrum management and node mobility using the pre-emptive resume priority M/G/1 queuing model and the gated node model respectively. We considered delay aware routing schemes; shortest queue and random probability routing and compared them with the analytical link-capacity for analysis. The study shows that already existing mathematical models can be used as close approximations to analyse the queuing models proposed for Cognitive Radio Ad Hoc Networks.
Detection of Malicious Portable Executables using Evidence Combinational Theory with Fuzzy Hashing
(IEEE, 2016) Namanya, Anitta Patience; Khan Ali Mirza, Qublai; Al-Mohannadi, Hamad; Awan, Irfan U.; Ferdinand Pagna Disso, Jules
Fuzzy hashing is a known technique that has been adopted to speed up malware analysis processes. However, Hashing has not been fully implemented for malware detection because it can easily be evaded by applying a simple obfuscation technique such as packing. This challenge has limited the usage of hashing to triaging of the samples based on the percentage of similarity between the known and unknown. In this paper, we explore the different ways fuzzy hashing can be used to detect similarities in a file by investigating particular hashes of interest. Each hashing method produces independent but related interesting results which are presented herein. We further investigate combination techniques that can be used to improve the detection rates in hashing methods. Two such evidence combination theory based methods are applied in this work in order propose a novel way of combining the results achieved from different hashing algorithms. This study focuses on file and section Ssdeep hashing, PeHash and Imphash techniques to calculate the similarity of the Portable Executable files. Our results show that the detection rates are improved when evidence combination techniques are used.
An Edge and Fog Computing Platform for Effective Deployment of 360 Video Applications
(IEEE., 2019) Rigazzi, Giovanni; Kainulainen, Jani-Pekka; Turyagyenda, Charles; Mourad, Alain; Ahn, Jaehyun
Immersive video applications based on 360 video streaming require high-bandwidth, high-reliability and low-latency 5G connectivity but also flexible, low-latency and cost-effective computing deployment. This paper proposes a novel solution for decomposing and distributing the end-to-end 360 video streaming service across three computing tiers, namely cloud, edge and constrained fog, in order of proximity to the end user client. The streaming service is aided with an adaptive viewport technique. The proposed solution is based on the H2020 5G-CORAL system architecture using micro-services-based design and a unified orchestration and control across all three tiers based on Fog05. Performance evaluation of the proposed solution shows noticeable reduction in bandwidth consumption, energy consumption, and deployment costs, as compared to a solution where the streaming service is all delivered out of one computing location such as the Cloud.
Prediction of cutting force for self-propelled rotary tool using artificial neural networks
(Journal of Materials Processing Technology, 2006) Hao, Wangshen; Zhu, Xunsheng; Li, Xifeng; Turyagyenda, Gelvis
In this paper, a cutting force model for self-propelled rotary tool (SPRT) cutting force prediction using artificial neural networks (ANN) has been introduced. The basis of this approach is to train and test the ANN model with cutting force samples of SPRT, from which their neurons relations are gradually extracted out. Then, ANN cutting force model is achieved by obtaining all weights for each layer. The inputs to the model consist of cutting velocity V, feed rate f, depth of cut ap and tool inclination angle λ, while the outputs are composed of thrust force Fx, radial force Fy and main cutting force Fz. It significantly reduces the complexity of modeling for SPRT cutting force, and employs non-structure operator parameters more conveniently. Considering the disadvantages of back propagation (BP) such as the convergence to local minima in the error space, developments have been achieved by applying hybrid of genetic algorithm (GA) and BP algorithm hence improve the performance of the ANN model. Validity and efficiency of the model were verified through a variety of SPRT cutting samples from our experiment tested in the cutting force model. The performance of the hybrid of GA–BP cutting force model is fairly satisfactory.
Integrated Cross-Layer Energy Savings in a Smart and Flexible Cellular Network
(IEEE., 2012) Guo, Weisi; Wang, Siyi; Turyagyenda, Charles; O’Farrell, Tim
A key challenge for mobile operators is how to reduce the operational energy and cost expenditure, whilst meeting the growing demand for throughput. In recent years, individual research techniques have shown that significant savings can be made. The majority of savings are achieved in the signal transmission stage and are obtained under certain modeling conditions and assumptions. How the gains can be combined together to yield higher total operational savings is largely unexplored, especially under a realistic multi-cell multi-user environment. This paper employs an integrated analysis of the cross-layer techniques that reduce energy consumption or improve the spectral- and energy- efficiency tradeoff. The research is part of the key integration process of the MVCE Green Radio (GR) programme, which combines architecture, transmission technique, resource management, and hardware research. The integrated operational energy savings have been shown to be above 90% and the associated cost savings are up to 34%. Furthermore, the paper discusses the impact of machine-learning and energy harvesting on the energy and cost consumption, to create a smart and flexible cellular network.
Garden Tool Transmission of Xanthomonas campestris pv. musacearum on Banana (Musa spp.) and Enset in Ethiopia
(Harnessing International, 2008) Addis, T.; Turyagyenda, L.F.; Alemu, T.; Karamura, E.; Blomme, G.
Xanthomonas wilt caused by Xanthomonas campestris pv. musacearum has been an important constraint to enset (Ensete ventricosum) and banana (Musa spp.) in Ethiopia. It was postulated that Xanthomonas wilt has a similar epidemiology as other banana bacterial wilts, which are known to be transmitted by insect vectors and garden tools. A study to determine the role of garden tools in the transmission of Xanthomonas wilt was carried out on enset in a greenhouse at the Southern Agricultural Research Institute, Awassa, Ethiopia and on ‘Pisang Awak’ (AABB genome) in the field at Amaro, Southern Ethiopia. A contaminated knife was used to infect plants. The treatments in the greenhouse trials comprised of cutting: green leaves; broken green leaves; dry leaves; the pseudostem; and roots. Similar treatments were carried out on the field-grown ‘Pisang Awak’ plants with two additional treatments: desuckering and debudding. Debudding was done by cutting off the male bud with a contaminated machete, while a forked stick was used for control samples. In addition, bacterial ooze was smeared on fresh and dry flower and bract scars at the male part of inflorescences. All plants treated with a contaminated machete: enset and banana when cut in the pseudostem; and all banana plants when debudded got infected. Similarly, cutting green leaves and cutting broken green leaves resulted in a high disease transmission of respectively 67 and 62% in banana and 58 and 54% in enset. Similar high transmission rates (90%) were obtained for desuckering on banana. On the other hand, cutting roots with a contaminated machete resulted in low transmission levels, with 20% in bananas and 25% in enset suggesting that tool infections mainly occur above ground. This calls for rigorous tool disinfection, while desuckering and deleafing in highly infected fields should be avoided. Debudding should be carried out with a forked stick.
Mobile Transport and Computing Platform for 5G Verticals: Resource Abstraction and Implementation
(IEEE., 2018) Sambo, N.; Valcarenghi, L.; Garcia-Saavedra, A.; Landi, G.; Pascual, I.; Vitale, C.; Ksentini, A.; Turyagyenda, C.
The 5G-TRANSFORMER project aims at transforming today's mobile transport networks into an SDN/NFV-based platform, which offers slices tailored to the needs of vertical industries. The paper describes the 5G-TRANSFORMER resource management layer, namely MTP, and its main functionalities such as resource abstraction, resource information modeling and orchestration, and service instantiation. Then, it focuses on the ETSI-based interfaces exploited for the interaction between the control and management plane elements. Finally, the paper reports an MTP implementation including messages reporting resource abstraction.
Sensitivity of mineral dissolution rates to physical weathering : A modeling approach
(European Geosciences Union (EGU), 2015) Opolot, Emmanuel; Finke, Peter
There is continued interest on accurate estimation of natural weathering rates owing to their importance in soil formation, nutrient cycling, estimation of acidification in soils, rivers and lakes, and in understanding the role of silicate weathering in carbon sequestration. At the same time a challenge does exist to reconcile discrepancies between laboratory-determined weathering rates and natural weathering rates. Studies have consistently reported laboratory rates to be in orders of magnitude faster than the natural weathering rates (White, 2009). These discrepancies have mainly been attributed to (i) changes in fluid composition (ii) changes in primary mineral surfaces (reactive sites) and (iii) the formation of secondary phases; that could slow natural weathering rates. It is indeed difficult to measure the interactive effect of the intrinsic factors (e.g. mineral composition, surface area) and extrinsic factors (e.g. solution composition, climate, bioturbation) occurring at the natural setting, in the laboratory experiments. A modeling approach could be useful in this case. A number of geochemical models (e.g. PHREEQC, EQ3/EQ6) already exist and are capable of estimating mineral dissolution / precipitation rates as a function of time and mineral mass. However most of these approaches assume a constant surface area in a given volume of water (White, 2009). This assumption may become invalid especially at long time scales. One of the widely used weathering models is the PROFILE model (Sverdrup and Warfvinge, 1993). The PROFILE model takes into account the mineral composition, solution composition and surface area in determining dissolution / precipitation rates. However there is less coupling with other processes (e.g. physical weathering, clay migration, bioturbation) which could directly or indirectly influence dissolution / precipitation rates.We propose in this study a coupling between chemical weathering mechanism (defined as a function of reactive area, solution composition, temperature, mineral composition) and the physical weathering module in the SoilGen model which calculates the evolution of particle size (used for surface area calculation) as influenced by temperature gradients. The solution composition in the SoilGen model is also influenced by other processes such as atmospheric inputs, organic matter decomposition, cation exchange, secondary mineral formation and leaching. We then apply this coupled mechanism on a case study involving 3 loess soil profiles to analyze the sensitivity of mineral weathering rates to physical weathering. Initial results show some sensitivity but not that dramatic. The less sensitivity was attributed to dominance of resistant primary minerals (> 70% quartz). Scenarios with different sets of mineralogy will be tested and sensitivity results in terms of silicate mineral dissolution rates and CO2-consumption will be presented in the conference.

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