Building a generalized distributed system model

A modeling tool for both analysis and design of distributed systems is discussed. Since many research institutions have access to networks of workstations, the researchers decided to build a tool running on top of the workstations to function as a prototype as well as a distributed simulator for a computing system. The effects of system modeling on performance prediction in distributed systems and the effect of static locking and deadlocks on the performance predictions of distributed transactions are also discussed. While the probability of deadlock is considerably small, its effects on performance could be significant

Providing Transaction Class-Based QoS in In-Memory Data Grids via Machine Learning

Elastic architectures and the ”pay-as-you-go” resource pricing model offered by many cloud infrastructure providers may seem the right choice for companies dealing with data centric applications characterized by high variable workload. In such a context, in-memory transactional data grids have demonstrated to be particularly suited for exploiting advantages provided by elastic computing platforms, mainly thanks to their ability to be dynamically (re-)sized and tuned. Anyway, when specific QoS requirements have to be met, this kind of architectures have revealed to be complex to be managed by humans. Particularly, their management is a very complex task without the stand of mechanisms supporting run-time automatic sizing/tuning of the data platform and the underlying (virtual) hardware resources provided by the cloud. In this paper, we present a neural network-based architecture where the system is constantly and automatically re-configured, particularly in terms of computing resources

New evidence on the green building rent and price premium

This paper investigates the effect of voluntary eco-certification on the rental and sale prices of US commercial office properties. Hedonic and logistic regressions are used to test whether there are rental and sale price premiums for LEED and Energy Star certified buildings. The results of the hedonic analysis suggest that there is a rental premium of approximately 6% for LEED and Energy Star certification. A sale price premium of approximately 35% was found for 127 price observations involving LEED rated buildings and 31% for 662 buildings involving Energy Star rated buildings. When compared to samples of similar buildings identified by a binomial logistic regression for LEED-certified buildings, the existence of a rent and sales price premium is confirmed albeit with differences regarding the magnitude of the premium. Overall, the results of this study confirm that LEED and Energy Star buildings exhibit higher rental rates and sales prices per square foot controlling for a large number of location- and property-specific factors

Report from GI-Dagstuhl Seminar 16394: Software Performance Engineering in the DevOps World

This report documents the program and the outcomes of GI-Dagstuhl Seminar 16394 "Software Performance Engineering in the DevOps World". The seminar addressed the problem of performance-aware DevOps. Both, DevOps and performance engineering have been growing trends over the past one to two years, in no small part due to the rise in importance of identifying performance anomalies in the operations (Ops) of cloud and big data systems and feeding these back to the development (Dev). However, so far, the research community has treated software engineering, performance engineering, and cloud computing mostly as individual research areas. We aimed to identify cross-community collaboration, and to set the path for long-lasting collaborations towards performance-aware DevOps. The main goal of the seminar was to bring together young researchers (PhD students in a later stage of their PhD, as well as PostDocs or Junior Professors) in the areas of (i) software engineering, (ii) performance engineering, and (iii) cloud computing and big data to present their current research projects, to exchange experience and expertise, to discuss research challenges, and to develop ideas for future collaborations

Building a generalized distributed system model

A number of topics related to building a generalized distributed system model are discussed. The effects of distributed database modeling on evaluation of transaction rollbacks, the measurement of effects of distributed database models on transaction availability measures, and a performance analysis of static locking in replicated distributed database systems are covered

On a Catalogue of Metrics for Evaluating Commercial Cloud Services

Given the continually increasing amount of commercial Cloud services in the market, evaluation of different services plays a significant role in cost-benefit analysis or decision making for choosing Cloud Computing. In particular, employing suitable metrics is essential in evaluation implementations. However, to the best of our knowledge, there is not any systematic discussion about metrics for evaluating Cloud services. By using the method of Systematic Literature Review (SLR), we have collected the de facto metrics adopted in the existing Cloud services evaluation work. The collected metrics were arranged following different Cloud service features to be evaluated, which essentially constructed an evaluation metrics catalogue, as shown in this paper. This metrics catalogue can be used to facilitate the future practice and research in the area of Cloud services evaluation. Moreover, considering metrics selection is a prerequisite of benchmark selection in evaluation implementations, this work also supplements the existing research in benchmarking the commercial Cloud services.Comment: 10 pages, Proceedings of the 13th ACM/IEEE International Conference on Grid Computing (Grid 2012), pp. 164-173, Beijing, China, September 20-23, 201

Leveraging Offshore IT Outsourcing by SMEs through Online Marketplaces

Following their larger counterparts, an increasing number of small firms outsource their IT tasks to lower cost offshore destinations. For small firms, however, offshore outsourcing is a difficult undertaking as it involves high transaction costs. Online marketplaces for IT services, which have recently become available to small firms, make offshore IT outsourcing more accessible and manageable, although differences in the marketplace design result in varying outcomes across the marketplaces. This has consequences for SME’s decision as to which online marketplace to use, because different markets may have different types of benefits and costs. This paper sets to analyze some of the similarities and differences between online marketplaces for IT services and their effects for small firms. First, we analyze if and how online marketplaces reduce small firms’ transaction costs in offshore IT outsourcing. Second, we examine the effects of market entry barriers on outcomes of online marketplaces and their implications for small firms. The results indicate that online marketplaces for IT services do reduce transaction costs for small firms in offshore outsourcing across ten specific market processes. More surprising, however, is the finding that the lower market entry barriers for suppliers result in lower prices for buyers without compromising other aspects of market performance.Offshore IT Outsourcing;Online Market;Process-Stakeholder Analysis;Reverse Auction

Customs-Related Transaction Costs, Firm Size and International Trade Intensity

The costs of paperwork and delays needed to clear international customs are generally perceived as a time-consuming impediment to international trade. However, few studies have empirically examined the determinants and the impact of this type of government-imposed transaction costs. This paper analyses the role of firm size as a determinant of customs-related transaction costs, as well as the effect of firm size on the relationship between these costs and the international trade intensity of firms. We submit that economies of scale should be related to the size of the activities the firm is specialised in, and not directly linked to the size of a firm per se.The results of this study indicate that customs-related transaction costs repress international trade activities of firms, even at low levels of these costs. The paper identifies transaction-related economies of scale, simplified customs procedures and advanced information and communication technology as main determinants of customs-related transaction costs. When these factors are taken into account, firm size has no effect on customs-related transaction costs. Policy implications are considered for firm strategy and public policy.firm size;international business strategy;international trade intensity;trade barriers

Relative investment specialisation inside EU: an econometric analysis for EU-regions

Models of economic geography predict an increase in concentration when transport costs diminish. These models, however, focus solely on the analysis of the production factor labour. Neglecting capital, though, might lead to disturbed results - particularly in the European context where capital, compared to labour, traditionally is the more mobile factor of production. In addition, a profound analysis of regional, not national, patterns of concentration is still missing in recent research. We regard regional data of the Eurostat REGIO database for the time period 1985 to 1994 and calculate indices of relative concentration of gross fixed capital formation (GFCF) for each region and each year. One important feature that can be detected is the higher level of relative investment concentration when regarding the more disaggregated NUTS 2-regions in comparison to NUTS 1-regions. In a descriptive analysis higher concentrated regions have been found to perform worse in economic terms than lower concentrated regions with respect to unemployment rate, number of patents, total regional GDP and total regional GFCF. Peripheral regions are often highly concentrated and of poorer economic performance than core regions. Economic centres, especially the region of Bruxelles and the Île de France, are highly concentrated as well. However, they demonstrate a good potential of high economic performance. As no causal relationship can be derived from this purely descriptive analysis, econometric analyses have to be conducted to test for the significance of potential determinants of agglomeration. The theoretical basis for the empirical investigation of the determinants of capital agglomeration are the results of models of the new international trade theory, the new economic geography as well as of gravity models (recently extended to the analysis of direct investment flows). They focus on determinants such as market size, factor endowments, distance (proxy for transport costs), scale intensities, technological capacities or research intensities, labour costs and liberalisation or integration effects. Results from cross-sectional and pooled regression analyses - controlling for problems of potential enodgeneity - point at a high importance of market size and regional size (having a decreasing impact on the level of investment concentration), the unemployment rate, and the centrality or population density of a region (increasing impact). The empirical effects of transport costs - though an important theoretical determinant in the new economic geography - are rather mixed. But, the impacts of integration, i.e. economic openness and capital account liberalisation, seem to enforce concentration tendencies. Between estimates, explaining the variation between regions, lead to results very similar to those of the cross-sectional and pooled estimates. By means of fixed effects estimates with highly significant region-specific effects and estimates in first differences, there are only few significant determinants to be detected. Thus, the variation within a region and the change in the level of concentration over time seem to be the result of random disturbances and not to underlie systematic changes. The robustness of our results will be checked applying spatial econometric tools taking account of regional interdependencies which are likely to occur when analysing regional effects and especially agglomeration tendencies.