A Satisfaction Balanced Query Allocation Process for Distributed Information Systems

National audienceWe consider a distributed information system that allows autonomous consumers to query autonomous providers. We focus on the problem of query allocation from a new point of view, by considering consumers and providers' satisfaction in addition to query load. We define satisfaction as a long-run notion based on the consumers and providers' intentions. Intuitively, a participant should obtain good satisfaction as far as it (the participant) is adequate to the system. We propose and validate a mediation process, called SBMediation, which is compared to CapacityBased query allocation. The experimental results show that SBMediation significantly outperforms CapacityBased when confronted to autonomous participants

Resource allocation for query processing in grid systems: A survey

Grid systems are very useful platforms for distributed databases, especially in some situations in which the scale of data sources and user requests is very high. However, the main characteristics of grid systems such as dynamicity, large size and heterogeneity, bring new problems to the query processing domain such as resource discovery and resource allocation. In this paper, we provide a survey related to resource allocation methods for query processing In data grid systems. We provide a classification for existing studies considering their approaches to the resource allocation problem. We provide a synthesis of the studies and propose evaluations and comparisons for the different classes of studies. ©2012 CRL Publishing Ltd

A network-aware framework for energy-efficient data acquisition in wireless sensor networks

Wireless sensor networks enable users to monitor the physical world at an extremely high fidelity. In order to collect the data generated by these tiny-scale devices, the data management community has proposed the utilization of declarative data-acquisition frameworks. While these frameworks have facilitated the energy-efficient retrieval of data from the physical environment, they were agnostic of the underlying network topology and also did not support advanced query processing semantics. In this paper we present KSpot+, a distributed network-aware framework that optimizes network efficiency by combining three components: (i) the tree balancing module, which balances the workload of each sensor node by constructing efficient network topologies; (ii) the workload balancing module, which minimizes data reception inefficiencies by synchronizing the sensor network activity intervals; and (iii) the query processing module, which supports advanced query processing semantics. In order to validate the efficiency of our approach, we have developed a prototype implementation of KSpot+ in nesC and JAVA. In our experimental evaluation, we thoroughly assess the performance of KSpot+ using real datasets and show that KSpot+ provides significant energy reductions under a variety of conditions, thus significantly prolonging the longevity of a WSN

Performance-Based Financing: Report on Feasibility and Implementation Options Final September 2007

This study examines the feasibility of introducing a performance-related bonus scheme in the health sector. After describing the Tanzania health context, we define “Performance-Based Financing”, examine its rationale and review the evidence on its effectiveness. The following sections systematically assess the potential for applying the scheme in Tanzania. On the basis of risks and concerns identified, detailed design options and recommendations are set out. The report concludes with a (preliminary) indication of the costs of such a scheme and recommends a way forward for implementation. We prefer the name “Payment for Performance” or “P4P”. This is because what is envisaged is a bonus payment that is earned by meeting performance targets1. The dominant financing for health care delivery would remain grant-based as at present. There is a strong case for introducing P4P. Its main purpose will be to motivate front-line health workers to improve service delivery performance. In recent years, funding for council health services has increased dramatically, without a commensurate increase in health service output. The need to tighten focus on results is widely acknowledged. So too is the need to hold health providers more accountable for performance at all levels, form the local to the national. P4P is expected to encourage CHMTs and health facilities to “manage by results”; to identify and address local constraints, and to find innovative ways to raise productivity and reach under-served groups. As well as leveraging more effective use of all resources, P4P will provide a powerful incentive at all levels to make sure that HMIS information is complete, accurate and timely. It is expected to enhance accountability between health facilities and their managers / governing committees as well as between the Council Health Department and the Local Government Authority. Better performance-monitoring will enable the national level to track aggregate progress against goals and will assist in identifying under-performers requiring remedial action. We recommend a P4P scheme that provides a monetary team bonus, dependent on a whole facility reaching facility-specific service delivery targets. The bonus would be paid quarterly and shared equally among health staff. It should target all government health facilities at the council level, and should also reward the CHMT for “whole council” performance. All participating facilities/councils are therefore rewarded for improvement rather than absolute levels of performance. Performance indicators should not number more than 10, should represent a “balanced score card” of basic health service delivery, should present no risk of “perverse incentive” and should be readily measurable. The same set of indicators should be used by all. CHMTs would assist facilities in setting targets and monitoring performance. RHMTs would play a similar role with respect to CHMTs. The Council Health Administration would provide a “check and balance” to avoid target manipulation and verify bonus payments due. The major constraint on feasibility is the poor state of health information. Our study confirmed the findings of previous ones, observing substantial omission and error in reports from facilities to CHMTs. We endorse the conclusion of previous reviewers that the main problem lies not with HMIS design, but with its functioning. We advocate a particular focus on empowering and enabling the use of information for management by facilities and CHMTs. We anticipate that P4P, combined with a major effort in HMIS capacity building – at the facility and council level – will deliver dramatic improvements in data quality and completeness. We recommend that the first wave of participating councils are selected on the basis that they can first demonstrate robust and accurate data. We anticipate that P4P for facilities will not deliver the desired benefits unless they have a greater degree of control to solve their own problems. We therefore propose - as a prior and essential condition – the introduction of petty cash imprests for all health facilities. We believe that such a measure would bring major benefits even to facilities that have not yet started P4P. It should also empower Health Facility Committees to play a more meaningful role in health service governance at the local level. We recommend to Government that P4P bonuses, as described here, are implemented across Mainland Tanzania on a phased basis. The main constraint on the pace of roll-out is the time required to bring information systems up to standard. Councils that are not yet ready to institute P4P should get an equivalent amount of money – to be used as general revenue to finance their comprehensive council health plans. We also recommend that up-to-date reporting on performance against service delivery indicators is made a mandatory requirement for all councils and is also agreed as a standard requirement for the Joint Annual Health Sector Review. P4P can also be applied on the “demand-side” – for example to encourage women to present in case of obstetric emergencies. There is a strong empirical evidence base from other countries to demonstrate that such incentives can work. We recommend a separate policy decision on whether or not to introduce demand-side incentives. In our view, they are sufficiently promising to be tried out on an experimental basis. When taken to national scale (all councils, excepting higher level hospitals), the scheme would require annual budgetary provision of about 6 billion shillings for bonus payments. This is equivalent to 1% of the national health budget, or about 3% of budgetary resources for health at the council level. We anticipate that design and implementation costs would amount to about 5 billion shillings over 5 years – the majority of this being devoted to HMIS strengthening at the facility level across the whole country

An Efficient Holistic Data Distribution and Storage Solution for Online Social Networks

In the past few years, Online Social Networks (OSNs) have dramatically spread over the world. Facebook [4], one of the largest worldwide OSNs, has 1.35 billion users, 82.2% of whom are outside the US [36]. The browsing and posting interactions (text content) between OSN users lead to user data reads (visits) and writes (updates) in OSN datacenters, and Facebook now serves a billion reads and tens of millions of writes per second [37]. Besides that, Facebook has become one of the top Internet traffic sources [36] by sharing tremendous number of large multimedia files including photos and videos. The servers in datacenters have limited resources (e.g. bandwidth) to supply latency efficient service for multimedia file sharing among the rapid growing users worldwide. Most online applications operate under soft real-time constraints (e.g., ≤ 300 ms latency) for good user experience, and its service latency is negatively proportional to its income. Thus, the service latency is a very important requirement for Quality of Service (QoS) to the OSN as a web service, since it is relevant to the OSN’s revenue and user experience. Also, to increase OSN revenue, OSN service providers need to constrain capital investment, operation costs, and the resource (bandwidth) usage costs. Therefore, it is critical for the OSN to supply a guaranteed QoS for both text and multimedia contents to users while minimizing its costs. To achieve this goal, in this dissertation, we address three problems. i) Data distribution among datacenters: how to allocate data (text contents) among data servers with low service latency and minimized inter-datacenter network load; ii) Efficient multimedia file sharing: how to facilitate the servers in datacenters to efficiently share multimedia files among users; iii) Cost minimized data allocation among cloud storages: how to save the infrastructure (datacenters) capital investment and operation costs by leveraging commercial cloud storage services. Data distribution among datacenters. To serve the text content, the new OSN model, which deploys datacenters globally, helps reduce service latency to worldwide distributed users and release the load of the existing datacenters. However, it causes higher inter-datacenter communica-tion load. In the OSN, each datacenter has a full copy of all data, and the master datacenter updates all other datacenters, generating tremendous load in this new model. The distributed data storage, which only stores a user’s data to his/her geographically closest datacenters, simply mitigates the problem. However, frequent interactions between distant users lead to frequent inter-datacenter com-munication and hence long service latencies. Therefore, the OSNs need a data allocation algorithm among datacenters with minimized network load and low service latency. Efficient multimedia file sharing. To serve multimedia file sharing with rapid growing user population, the file distribution method should be scalable and cost efficient, e.g. minimiza-tion of bandwidth usage of the centralized servers. The P2P networks have been widely used for file sharing among a large amount of users [58, 131], and meet both scalable and cost efficient re-quirements. However, without fully utilizing the altruism and trust among friends in the OSNs, current P2P assisted file sharing systems depend on strangers or anonymous users to distribute files that degrades their performance due to user selfish and malicious behaviors. Therefore, the OSNs need a cost efficient and trustworthy P2P-assisted file sharing system to serve multimedia content distribution. Cost minimized data allocation among cloud storages. The new trend of OSNs needs to build worldwide datacenters, which introduce a large amount of capital investment and maintenance costs. In order to save the capital expenditures to build and maintain the hardware infrastructures, the OSNs can leverage the storage services from multiple Cloud Service Providers (CSPs) with existing worldwide distributed datacenters [30, 125, 126]. These datacenters provide different Get/Put latencies and unit prices for resource utilization and reservation. Thus, when se-lecting different CSPs’ datacenters, an OSN as a cloud customer of a globally distributed application faces two challenges: i) how to allocate data to worldwide datacenters to satisfy application SLA (service level agreement) requirements including both data retrieval latency and availability, and ii) how to allocate data and reserve resources in datacenters belonging to different CSPs to minimize the payment cost. Therefore, the OSNs need a data allocation system distributing data among CSPs’ datacenters with cost minimization and SLA guarantee. In all, the OSN needs an efficient holistic data distribution and storage solution to minimize its network load and cost to supply a guaranteed QoS for both text and multimedia contents. In this dissertation, we propose methods to solve each of the aforementioned challenges in OSNs. Firstly, we verify the benefits of the new trend of OSNs and present OSN typical properties that lay the basis of our design. We then propose Selective Data replication mechanism in Distributed Datacenters (SD3) to allocate user data among geographical distributed datacenters. In SD3,a datacenter jointly considers update rate and visit rate to select user data for replication, and further atomizes a user’s different types of data (e.g., status update, friend post) for replication, making sure that a replica always reduces inter-datacenter communication. Secondly, we analyze a BitTorrent file sharing trace, which proves the necessity of proximity-and interest-aware clustering. Based on the trace study and OSN properties, to address the second problem, we propose a SoCial Network integrated P2P file sharing system for enhanced Efficiency and Trustworthiness (SOCNET) to fully and cooperatively leverage the common-interest, geographically-close and trust properties of OSN friends. SOCNET uses a hierarchical distributed hash table (DHT) to cluster common-interest nodes, and then further clusters geographically close nodes into a subcluster, and connects the nodes in a subcluster with social links. Thus, when queries travel along trustable social links, they also gain higher probability of being successfully resolved by proximity-close nodes, simultaneously enhancing efficiency and trustworthiness. Thirdly, to handle the third problem, we model the cost minimization problem under the SLA constraints using integer programming. According to the system model, we propose an Eco-nomical and SLA-guaranteed cloud Storage Service (ES3), which finds a data allocation and resource reservation schedule with cost minimization and SLA guarantee. ES3 incorporates (1) a data al-location and reservation algorithm, which allocates each data item to a datacenter and determines the reservation amount on datacenters by leveraging all the pricing policies; (2) a genetic algorithm based data allocation adjustment approach, which makes data Get/Put rates stable in each data-center to maximize the reservation benefit; and (3) a dynamic request redirection algorithm, which dynamically redirects a data request from an over-utilized datacenter to an under-utilized datacenter with sufficient reserved resource when the request rate varies greatly to further reduce the payment. Finally, we conducted trace driven experiments on a distributed testbed, PlanetLab, and real commercial cloud storage (Amazon S3, Windows Azure Storage and Google Cloud Storage) to demonstrate the efficiency and effectiveness of our proposed systems in comparison with other systems. The results show that our systems outperform others in the network savings and data distribution efficiency

A user perspective of quality of service in m-commerce

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2004 Springer VerlagIn an m-commerce setting, the underlying communication system will have to provide a Quality of Service (QoS) in the presence of two competing factors—network bandwidth and, as the pressure to add value to the business-to-consumer (B2C) shopping experience by integrating multimedia applications grows, increasing data sizes. In this paper, developments in the area of QoS-dependent multimedia perceptual quality are reviewed and are integrated with recent work focusing on QoS for e-commerce. Based on previously identified user perceptual tolerance to varying multimedia QoS, we show that enhancing the m-commerce B2C user experience with multimedia, far from being an idealised scenario, is in fact feasible if perceptual considerations are employed

Satisfaction Balanced Mediation

International audienceWe consider a distributed information system that allows autonomous consumers to query autonomous providers. We focus on the problem of query allocation from a new point of view, by considering consumers and providers' satisfaction in addition to query load. We define {\it satisfaction} as a long-run notion based on the consumers and providers' preferences. We propose and validate a mediation process, called SBMediation, which is compared to CapacityBased query allocation. The experimental results show that SBMediation significantly outperforms CapacityBased when confronted to autonomous participants

Improving the translation environment for professional translators

When using computer-aided translation systems in a typical, professional translation workflow, there are several stages at which there is room for improvement. The SCATE (Smart Computer-Aided Translation Environment) project investigated several of these aspects, both from a human-computer interaction point of view, as well as from a purely technological side. This paper describes the SCATE research with respect to improved fuzzy matching, parallel treebanks, the integration of translation memories with machine translation, quality estimation, terminology extraction from comparable texts, the use of speech recognition in the translation process, and human computer interaction and interface design for the professional translation environment. For each of these topics, we describe the experiments we performed and the conclusions drawn, providing an overview of the highlights of the entire SCATE project