How replicated data management in the cloud can benefit from a data grid protocol - the Re:GRIDiT Approach

Cloud computing has recently received considerable attention both in industry and academia. Due to the great success of the first generation of Cloud-based services, providers have to deal with larger and larger volumes of data. Quality of service agreements with customers require data to be replicated across data centers in order to guarantee a high degree of availability. In this context, Cloud Data Management has to address several challenges, especially when replicated data are concurrently updated at different sites or when the system workload and the resources requested by clients change dynamically. Mostly independent from recent developments in Cloud Data Management, Data Grids have undergone a transition from pure file management with read only access to more powerful systems. In our recent work,we have developed the Re:GRIDiT protocol for managing data in the Grid which provides concurrent access to replicated data at different sites without any global component and supports the dynamic deployment of replicas. Since it is independent from the underlying Grid middleware, it can be seamlessly transferred to other environments like the Cloud.In this paper, we compare Data Management in the Grid and the Cloud, briefly introduce the Re:GRIDiT protocol and show its applicability for Cloud Data Management

Arthrospira Platensis – Potential in Dermatology and Beyond

The search for natural products with benefits for health in general and of potential for treating human disease has gained wider interest world-wide. Here, we analyse current data on the microalga Arthrospira platensis (AP), that has been used in nutrition since ancient times in Fare East and African communities, for medical purposes with a focus on dermatology. Extracts of AP have been investigated in vitro and in vivo. The alga is rich in proteins, lipopolysaccharides and gamma-linolenic acid. AP extracts, phycocyanin compounds and polysaccharide calcium spirulan (Ca-SP) have been evaluated in various models. It could be demonstrated, that AP has significant antioxidant activity, prevents viruses from entry into target cells and inhibits the colonisation of wounds by multi-resistant bacteria. Furthermore, anti-cancer activity was documented in models of oral cancer, melanoma, and UV-induced non-melanoma skin cancer

Interstitial Granulomatous Dermatitis (IGD)

We report the case of a 42 years old male patient suffering from skin changes , which appeared in the last 7-8 years.  Two biopsies were performed during the evolution of the lesion. Both showed similar findings that consisted in a busy dermis with interstitial, superficial and deep infiltrates of lymphocytes and histiocytes dispersed among collagen bundles, with variable numbers of neutrophils scattered throughout. Some histiocytes were clustered in poorly formed granuloma that included rare giant cells, with discrete Palisades and piecemeal collagen degeneration, but without mucin deposition or frank necrobiosis of collagen. The clinical and histologic findings were supportive for interstitial granulomatous dermatitis. Interstitial granulomatous dermatitis (IGD) is a poorly understood entity that was regarded by many as belonging to the same spectrum of disease or even synonym with palisaded and neutrophilic granulomatous dermatitis (PNGD). Although IGD and PNGD were usually related to connective tissue disease, mostly rheumatoid arthritis, some patients with typical histologic findings of IGD never develop autoimmune disorders, but they have different underlying conditions, such as metabolic diseases, lymphoproliferative disorders or other malignant tumours. These observations indicate that IGD and PNGD are different disorders with similar manifestations

Basal Cell Carcinoma Surgery: Simple Undermining Approach in Two Patients with Different Tumour Locations

Basal cell carcinoma (BCC) is the most common human malignancy, accounting for the majority of all non-melanoma skin cancers (NMSC). In the past several decades the worldwide incidence of BCC has constantly been increasing. Even though it is a slow growing tumour that, left untreated, rarely metastasizes, it has a distinctive invasive growth pattern, posing a considerable risk for local invasion and destruction of underlying tissues, such as muscle, cartilage, bone or vital structures. Advanced BCCs include such locally invasive or metastatic tumours. Complete surgical excision is the standard therapy for most uncomplicated BCC cases with good prognosis and cure rates. Treatment of advanced forms of BCCs poses significant therapeutic challenges, most often requiring complicated surgery, radiotherapy, and/or targeted therapies directed towards the sonic hedgehog signalling pathway (SHH). We present two cases of large BCCs located on the scalp and posterior thorax, which underwent surgical excision with clear margins, followed by reconstruction of the defect after extensive undermining of the skin

Dynamic data replication in the grid with freshness and correctness guarantees

This thesis explores architectural issues and performance aspects of data Grid infrastructures. The objective is to develop a scalable infrastructure that is capable to dynamically manage replicated data in the Grid while at the same time providing freshness and correctness guarantees. We propose a decentralized middleware which can be deployed on top of any Grid (or any distributed, heterogeneous) infrastructure. The difficulty is to ensure that such an infrastructure can offer scalability, performance and correctness. The overall goal of this thesis is to present a replication mechanism that combines scalability, global correctness and quality of service guarantees in a dynamic way. In the beginning we introduce important aspects of Grid environments and several scenarios from newly emerging eScience applications. These use case scenarios urgently require new integrated approaches to dynamic replication in a data Grid. Our main contribution is the Re:GRIDiT protocols that dynamically manage replicas in the Grid, while at the same time providing freshness and correctness guarantees. The Re:GRIDiT family consists of three different protocols which target the three main problematic aspects identified in current data Grid infrastructures. Inspired by the requirements deduced from these scenarios we first concentrate our efforts on the more complex and general case of distributed update transactions on replicated data. We devise a protocol for the correct synchronization of concurrent updates to different updateable replicas in order to ensure their subsequent propagation to read-only replicas in a completely distributed way. Re:SYNCiT hides the presence of replicas to the applications, takes into account the special characteristics of data in the Grid such as version support, distinction between mutable and immutable objects, and provides provably correct transactional execution guarantees without any global component. The next step is the Re:LOADiT approach to dynamic distributed replica management in data Grid systems. We propose efficient algorithms for selecting optimal locations for placing the replicas so that the load among these replicas is balanced. Given the data usage from each user site and the maximum load of each replica, our algorithm efficiently manages the number of replicas required, reducing or increasing their number. Until now our approach dictates how update sites behave and from a user's point of view the clients will always access the most up-to-date data. We further refine this approach and introduce the Re:FRESHiT protocol, which allows to effectively trade freshness for performance and addresses freshness and versioning issues, needed in many Grid application domains, without losing consistency. Queries with different freshness levels are cleverly routed along our tree strategy, by taking advantage of the tree structure. Finally we are also interested in the performance characteristics of the presented algorithms. We have implemented the Re:GRIDiT protocols using state-of-the-art Web service technologies which allows an easy and seamless deployment in any Grid environment. The evaluation has been conducted on up to 48 update sites and 48 read-only sites. We have used simulated workloads that mimic the behavior expected from our use case applications. Our evaluations have shown that the proposed Re:GRIDiT protocols are efficient, as replicas are created and/or deleted on demand and with a reasonable amount of resources. Dynamic changes in the tree structure allow flexible and efficient query routing along the tree structure. Clever routing strategies ensure an increased performance for queries with different freshness levels. Re:GRIDiT ensures replica consistency and is capable of providing different degrees of consistency and update frequencies. Summarizing, this thesis presents new approaches for the correct synchronization of updates in a dynamic manner, replication management, and freshness guarantees in a data Grid. These approaches are founded on formal theoretical background and implemented in a full-fledged prototype in a realistic Grid environment. These approaches have been proven to be scalable by means of an extensive analytical and experimental evaluation

MOMC: Multi-objective and Multi-constrained Scheduling Algorithm of Many Tasks in Hadoop

(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Even though scheduling in a distributed system was debated for many years, the platforms and the job types are changing everyday. This is why we need special algorithms based on new applications requirements, especially when a application is deployed in a Cloud environment. One of the most important framework used for large-scale data processing in Clouds is Hadoop and its extensions. Hadoop framework comes with default algorithms like FIFO, Fair Scheduler or Capacity Scheduler, and Hadoop on Demand. These scheduling algorithms are focused on a different and single constraint. It is hard to satisfy multiple constraints and to have a lot of objectives in the same time. After summarizing the most common schedulers, showing the need of each one in the moment it appeared on the market, this paper presents MOMC, a multi-objective and multi-constrained scheduling algorithm of many tasks in Hadoop. MOMC implementation focuses on two objectives: avoiding resource contention and having an optimal workload of the cluster, and two constraints: deadline and budget. To compare the algorithms based on different metrics, we use Scheduling Load Simulator, which is integrated in Hadoop framework and helps the developers to spend less time on testing. As killer application that generate many tasks we have chosen processing task for the Million Song Dataset, which is a set of data contains metadata for one million commercially-available songs.Peer Reviewe

Thermal Evaluation of an Innovative Type of Unglazed Solar Collector for Air Preheating

International audiencePerforated solar walls pre-heat the fresh air introduced in the building when the air is forced to pass through this solar heated perforated facade. The heat transfer between the fluid and the metal is intensified depending especially on the flow's characteristics. An experimental campaign on an innovative solar collector was performed in the laboratory of Building Services from Technical University of Civil Engineering Bucharest. The solar collector with lobed perforations was analyzed and the results indicated that the system can attain a high thermal performance, but only for a certain range of airflow rate

Replicated Data Management in the Grid: The Re:GRIDiT Approach

Grid environments more and more target novel domains suchas eScience, eHealth or digital libraries that feature a varietyof data-intensive applications. Consequently, issues relatedto data management in Grids are becoming increasingly important.In terms of data management, the Grid allowskeeping a large number of replicas of data objects, possiblywith different versions or levels of freshness, to allow for ahigh degree of availability, reliability and performance so asto best meet the needs of users and applications. At thesame time, the seamless integration of replication managementinto the Grid while taking into account its special characteristics,needs to be done without any central componentfor managing data or metadata. In this paper, we report onthe ongoing Re:GRIDiT project which aims at addressingall the above requirements. Re:GRIDiT distinguishes betweenpotentially many updateable and read-only replicaswhich can be distributed across a Grid environment. First,Re:GRIDiT provides new protocols for the correct synchronizationof concurrent updates to different updateable replicasand their subsequent propagation in a completely distributedway. Second, Re:GRIDiT takes into account thesemantics of the data which is managed in the Grid: mutabledata can be subject to updates; immutable data, in turn,cannot be changed once created, but may be subject to versioncontrol. Third, Re:GRIDiT will be dynamic in a waythat according to the current load, new replicas (updateableor read-only) can be created or removed on demand. Fourth, Re:GRIDiT will provide read-only transactions the full flexibilityto specify the freshness (for mutable data) or versionnumber (for immutable data) – which is particularly usefulin order to trade accuracy for performance in the access todata in the Grid

MOMC: Multi-objective and Multi-constrained scheduling algorithm of many tasks in Hadoop

(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Even though scheduling in a distributed system was debated for many years, the platforms and the job types are changing everyday. This is why we need special algorithms based on new applications requirements, especially when a application is deployed in a Cloud environment. One of the most important framework used for large-scale data processing in Clouds is Hadoop and its extensions. Hadoop framework comes with default algorithms like FIFO, Fair Scheduler or Capacity Scheduler, and Hadoop on Demand. These scheduling algorithms are focused on a different and single constraint. It is hard to satisfy multiple constraints and to have a lot of objectives in the same time. After summarizing the most common schedulers, showing the need of each one in the moment it appeared on the market, this paper presents MOMC, a multi-objective and multi-constrained scheduling algorithm of many tasks in Hadoop. MOMC implementation focuses on two objectives: avoiding resource contention and having an optimal workload of the cluster, and two constraints: deadline and budget. To compare the algorithms based on different metrics, we use Scheduling Load Simulator, which is integrated in Hadoop framework and helps the developers to spend less time on testing. As killer application that generate many tasks we have chosen processing task for the Million Song Dataset, which is a set of data contains metadata for one million commercially-available songs.Peer Reviewe

Re:GRIDiT – Coordinating Distributed Update Transactions on Replicated Data in the Grid

The recent proliferation of Grid environments foreScience applications led to common computing infrastructureswith nearly unlimited storage capabilities. Interms of data management, the Grid allows keeping alarge number of replicas of data objects to allow for ahigh degree of availability, reliability and performance.Due to the particular characteristics of the Grid,especially due to the absence of a global coordinator,dealing with many updateable replicas per data objecturgently requires new protocols for the synchronizationof updates and their subsequent propagation. Currentlythere is no protocol which can be seamlessly applied toa data Grid environment without impacting correctnessand/or overall performance. In this paper we addressthe problem of replication in the Data Grid in thepresence of updates. We have designed the Re:GRIDiTprotocol that focuses on the correct synchronization ofupdates to several replicas in the Grid in a completelydistributed way, extending well-established databasereplication techniques. Globally correct execution isprovided by communication between transactions andsites. Re:GRIDiT takes into account the special characteristicsof eScience applications such as the distinctionbetween mutable objects, that can be updated byusers and immutable objects. Finally, we provide a detailedevaluation of the performance of the Re:GRIDiTprotocol when being applied at Grid scale