179 research outputs found
Architecture of a Network Monitoring Element
No full textSUMMARY A Network Monitoring system is a vital component of a Grid; however, its scalability is a challenge. We propose a network monitoring approach that combines passive monitoring, a domain oriented overlay network, and an attitude for demand driven monitoring sessions. In order to keep into account the demand for extreme scalability, we introduce a solution for two problems that are inherent to the proposed approach: security and group membership maintenance
Work-related leukemia: A systematic review
No full textLeukemia is a complex disease, which only became better understood during the last decades following the development of new laboratory techniques and diagnostic methods. Despite our improved understanding of the physiology of the disease, little is yet known about the causes of leukemia. A variety of potential risk factors have been suggested so far, including personal habits and lifestyle, and a wide range of occupational or environmental exposures. A causal association with leukemia has only been documented to date for ionizing radiation, benzene and treatment with cytostatic drugs, but there is an ongoing scientific debate on the possible association of leukemia with a number of other work-related hazards. In this article, we have reviewed scientific studies, published over the past 5 years, which investigated potential associations between leukemia and exposure to occupational risk factors. The systematic literature review took place via electronic databases, using specific search criteria, and independent reviewers have further filtered the search results to identify the number of articles, presented in our paper. A large number of studies included in the review referred to the effects of ionizing radiation, where new data suggest that the effects of exposure to small doses of ionizing radiation should probably be reevaluated. Some other works appear to substantiate a potential association of the disease with certain pesticides. Further research is also suggested regarding the role of infectious agents or exposure to certain chemicals like formaldehyde or butadiene in the pathogenesis of leukemia. © 2013 Polychronakis et al.; licensee BioMed Central Ltd
Rapid Control Prototyping in a three phase grid-tie BSNPC inverter - Sensors, PWM and control concepts
No full textIn these ages of a more and more increasing energy demand and struggle to reduce CO2 emissions, the need of robust, analytical and fast ways to introduce new alternative energy concepts into practice is imminent. Nowadays, engineers struggle to incorporate all parts of modern power electronic applications, such as new topologies, control concepts, supportive features, into compact structures and that require the joining of forces between different sectors of the electrical engineering _eld. Digital technology, new materials and new control ideas should be combined to produce what is envisioned by new engineers as high end technology for renewable energy systems. One such way to simplify the cooperation of different electrical engineering fields is Rapid Control Prototyping (RCP). In RCP applications, a plant controller is implemented using a real-time simulator and is connected to a physical plant having many advantages over implementing an actual controller prototype. A controller prototype developed using a real-time simulator is more flexible, faster to implement and easier to debug. The project considered in this master thesis involves a Rapid Control Prototyping system for a three-phase grid-tie BSNPC IGBT inverter. A Rapid Control Prototyping system, as mentioned before, includes a computer that runs the Simulink software, a Real Time Computer that runs a compiled version of the Simulink model and the actual hardware. The hardware in the existing case comprises a custom board designed and manufactured especially for this master thesis project and already existing inverter hardware. The custom board acts as an intermediate between the controlling computers and the hardware. It receives and sends signals to and from the Real Time Computer as well as the inverter hardware, is capable of fully operating the hardware and providing the controlling computers with full data and information about the hardware. The data transmissions between the systems are done real-time while the inverter hardware is in operation and the editing and producing of new data is also done in real-time. The data processing inside the two controlling computers is also done in real-time and permits the testing and operation of the hardware simultaneously with its change in control variables, gains and duty cycles. The ease of operation of such a system and the full controllability and flexibility makes it perfect for testing in power electronic applications.Electrical Power EngineeringEWIElectrical Engineering, Mathematics and Computer Scienc
The impact of horizontal mergers and acquisitions on supply chain management : the case of the industrial maintenance, repair and overhaul distribution sector
No full textA great majority of commercial businesses plan to or, at least, desire to grow and expand their operations, enter new markets, obtain new technologies, and find new customers. These goals can be achieved in an organic way through slow expansion, steady project investment, gradual growth of sales, investment in R&D (research and development), etc. Another way, one that is much quicker and that can offer instantaneous growth, is through mergers with or acquisitions of (M&As) other businesses. If all goes well, M&A deals can reward numerous stakeholders, including institutional and individual shareholders, suppliers, customers as well as employees. Mergers and acquisitions can drive company growth enormously, multiplying turnover just in a matter of years. The rewards are very promising. On the flip side, however, many M&A initiatives either fail or do not deliver initially set objectives, as will be discussed later in the study. In the last two decades, numerous authors have researched the M&A area, often in an attempt to understand barriers to and enablers of successful merger and acquisition deal completion and realisation. These authors have looked into various aspects of the M&A process, including human resource management and customer management, sales channels integration, and have diligently scrutinised the financial and strategic characteristics of M&A deals. Surprisingly, despite the abundance of research and knowledge, the M&A completion success rate has not been improving by any significant measure, yet this has not discouraged organisations from pursuing these, as is now known, high risk growth strategies. In this research the author is looking at supply chains of businesses concerned with the subject of mergers and acquisitions. Organisations may either be conducting an acquisition, or becoming acquired by somebody else, or may be merging with another business. Thorough consideration is given to the pre-acquisition or pre-merger stage of the process, as well as to post-acquisition or post-merger supply chain practices and integration. The author believes that skilful supply chain management, including the integration of merging supply chains, can help to improve the chances of successful M&A deal completion through the enabling of full potential realisation within the shortest possible time. What is more, to date, very limited research has been carried out on the subject, and so there is a direct need for the study
Demand Forecasting In Manufacturing Pharmaceutical Small and Medium Enterprise’s (SME’s) In Ghana
No full textForecasting is a ubiquitous, multi-discipline area which has received much attention from practitioners and researchers for many several years. It permeates every facet of an organisation’s life as the bedrock of planning and decision making. An organisation’s ability to accurately predict future demand affect cost, supply chain and customer service generating significant gains for an organization. Organisations need to forecast to meet the increasing expectations of customers, shorten lead times and for production and procurement decisions. A plethora of studies have established the damaging impact of poor forecast, from excessive inventory to reduced customer service. A poor choice of forecast method and neglect of high forecast errors is a common cause of organisation’s problems and supply chain disruptions. This thesis focuses on demand forecasting in Manufacturing Pharmaceutical (Mpharma) SMEs in Ghana to address the gap of insufficient research within the context and the calls for empirical studies on forecasting in emerging economies. The pharmaceutical industry is constantly forecasting to tackle current unfulfilled needs and for drug innovation; from manufacturing of drugs till the time it reaches the customer. Forecasting’s role in the pharmaceutical sector is to inform both clinical and non-clinical decisions and determine how a drug will perform commercially. This study investigate how Mpharma SMEs in Ghana forecast demand, the methods used in forecasting, the importance of accurately forecasting demand as well as the barriers they encounter and how they mitigate these challenges. The investigation was exploratory, framed on phenomenological philosophy and inductive approach. face-to-face semi-structured interviews which involved 14 pharmaceutical manufacturing SMEs were conducted and the qualitative data collected thematically analysed. The findings confirmed that MPharma SMEs in Ghana forecast demand and encounter divers’ challenges though the forecasting practices differ to an extent among the participating SMEs. It confirmed the lack of formal organisation structures and dedicated /expert forecasters for SMEs, and this is due to their size, limited financial and manufacturing resources. The activity is generally performed by the marketing, sales or purchasing managers or owner CEO’S. Judgement approach was the preferred forecasting approach and technology adoption significantly low. All the SMEs are challenged due to lack of data, lack of training and introduction of new legislations to mention a few. A significant finding of this study is the non-existence of intermittent/ irregular demand forecasting among all the participating SME’s echoing the forecasting gap in the industry. Though typically the forecasting process of pharmaceuticals is long and winding, the case is different for generic drug manufacturers. Most MPharma in Ghana produce generic drugs explaining the flexibility but lack of structure of their forecasting processes. The thesis concludes and makes recommendations and suggestions for further research highlighting limitation to the study
On the interactions between supply chain and project management : theoretical and empirical considerations
No full textThe research presented in this document is predominantly addressed via eight main journal publications and further supported by fifteen conference proceedings, other industrial projects and research grants. The research rests on two interlinked main pillars within the overall scientific discipline of Operations Management namely Supply Chain Management and Project Management. It focuses on "softer" contemporary themes where the overall contribution falls within the thematic area of collaboration, integration and development. The contribution is realized via research in numerous "softer" contemporary themes such as leadership styles, organizational structures and cultures, cooperation, knowledge management, usage of new technologies and strategy, all within the two aforementioned pillars. Application ranges from private small medium enterprises to larger organizations and to the public sector. In that respect my research addresses the needs of practitioners while providing a clear contribution to the relevant body of knowledge.Methodologically, the work presented here utilizes the grounded theory approach. Arguably, large sample, positivistic driven, survey methodologies are certainly very useful in providing an understanding of "how much" and "how many" as well as drawing inferences to a larger population. Nevertheless, they cannot provide the information required regarding "how" or "why" events occur which relate directly to most of the work presented in this document. Consequently, a case-based methodology has been employed directly or indirectly in all papers addressed here. In all instances the main criterion used to select cases as part of the data collection process was based on theoretical relevance
The impact of judgment on statistical forecasts
No full textThe thesis will aim to empirically assess how judgment impacts a statistical forecast in a spare parts supply chain.The thesis will investigate what impact judgment has on forecast accuracy that is, does it improve the statistical forecast. If so, is there specific types of demand series, spare parts types or expertise which can affect the accuracy improvement. The results will be used to provide a matrix showing where judgment should or should not be applied to a statistical forecast with regards to accuracy improvement.The size and direction of the judgmental adjustment will be scrutinised to explore where any correlation can be found to accuracy improvement. The experiment will be for a 12 months longitudinal period using forecast experts who are working in a company and are forecasting the same spare parts on a day to day basis. The statistical forecast used will be the method that the company uses on a day to day basis. In order to benchmark the performance of the experts a senior academic will also be forecasting the spare parts involved over the same period in order to show another comparison but with a more considered, complex statistical forecast rather than the relatively simple average based statistical forecast the company used.Insights into further research, limitations of the experiment and a conclusion stating the impact to academic knowledge and possible practitioner usage will be discussed
ORIGINAL PAPER Network-level polymorphic shellcode detection using emulation
No full textAbstract Significant progress has been made in recent years towards preventing code injection attacks at the network level. However, as state-of-the-art attack detection technology becomes more prevalent, attackers are likely to evolve, employing techniques such as polymorphism and metamorphism to defeat these defenses. A major outstanding question in security research and engineering is thus whether we can proactively develop the tools needed to contain advanced polymorphic and metamorphic attacks. While recent results have been promising, most of the existing proposals can be defeated using only minor enhancements to the attack vector. In fact, some publicly-available polymorphic shellcode engines are currently one step ahead of the most advanced publicly-documented network-level detectors. In this paper, we present a heuristic detection method that scans network traffic streams for the presence of previously unknown polymorphic shellcode. In contrast to previous work, our approach relies on a NIDSembedded CPU emulator that executes every potential instruction sequence in the inspected traffic, aiming to identify the execution behavior of polymorphic shellcode. Our analysis demonstrates that the proposed M. Polychronakis (B) · E. P. Markato
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