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2.
The lack of precision to predict service performance through load indices may lead to wrong decisions regarding the use of web services, compromising service performance and raising platform cost unnecessarily. This paper presents experimental studies to qualify the behaviour of load indices in the web service context. The experiments consider three services that generate controlled and significant server demands, four levels of workload for each service and six distinct execution scenarios. The evaluation considers three relevant perspectives: the capability for representing recent workloads, the capability for predicting near-future performance and finally stability. Eight different load indices were analysed, including the JMX Average Time index (proposed in this paper) specifically designed to address the limitations of the other indices. A systematic approach is applied to evaluate the different load indices, considering a multiple linear regression model based on the stepwise-AIC method. The results show that the load indices studied represent the workload to some extent; however, in contrast to expectations, most of them do not exhibit a coherent correlation with service performance and this can result in stability problems. The JMX Average Time index is an exception, showing a stable behaviour which is tightly-coupled to the service runtime for all executions. Load indices are used to predict the service runtime and therefore their inappropriate use can lead to decisions that will impact negatively on both service performance and execution cost. 相似文献
3.
PurposeThis literature review aims to present the current methodologies that have been developed to perform a social life cycle assessment (sLCA) and to display the main differences among them. In addition to that, to identify the nexus between sLCA and circular economy (CE) and to what extent this life cycle technique has been involved within CE studies. MethodsAn analysis of scientific literature using online databases was made. A total of 76 publications, including all industry sectors worldwide, were chosen spanning 11 years, from 2009 to 2020. Special attention was made to the methodology used to assess the social impacts, the impact categories analyzed, and whether there is or not a circular economy case. All the impact categories of both UNEP/SETAC and PSIA were taken into account when doing the review, and the top three of the categories are mentioned here. Results and discussionThe leadership of the UNEP/SETAC methodology is clear with 58 cases. Almost 90% of the case studies are focused on products while the remaining ones are related with services. Workers are the most considered stakeholder when conducting an sLCA research, followed by local communities and society. Regarding the impact assessment, the performance reference point (PRP) was the most common method used. When considering the CE even when some cases included the end-of-life stage in the system boundaries, the studies did not consider the actors from that stage; excluding these cases, one out of four articles has a link with CE, a promising proportion taking into account the early stage of both concepts (i.e., sLCA and CE). ConclusionsUNEP/SETAC guidelines seem to be the most promising methodology due to its reception among the scientific community. However, a more industry-oriented approach is proposed by the Roundtable for Product Social Metrics (PSIA) in a way to respond to manufacturing companies’ demand. Regardless of the type of methodology to be implemented, workers represent the key stakeholder when assessing social impacts. The change in usual patterns is leading to a change in the way how stakeholders interact and therefore new and more impacts may arise, and that is the reason why it is important to include the CE into the sLCA. A series of challenges such as the feasibility of aggregating all the life cycle techniques to one (life cycle sustainability assessment), data availability, and quality are still present for the moment. 相似文献
4.
The typology of wetlands provides important information for both water resource managers and conservation planners. One of the most important aims of allocating wetlands to a certain type or class is to provide information about the ecosystem services that the wetland provides. There are two main approaches towards wetland classification. Firstly, there are top-down approaches whereby wetlands are divided into several categories based on a conceptual understanding of how the wetland functions (mostly with regards to water flows). Secondly there are bottom-up approaches whereby the classification of wetlands is based on the collection of data in the wetland that is then subjected to various clustering techniques (mostly with regards to biodiversity). The most utilized system of top-down classification assigns wetlands into hydrogeomorphic units, which function as a single unit in terms of hydrology and geomorphology. This type of classification is most useful for water resource planning, as it provides information about how the wetland is connected to the drainage network and what are the water inflows, throughflows and outflows of the wetland. The bottom-up classification approach typically focusses on the classification of wetland habitats rather than complete wetlands, where wetland habitat represents a spatial unit delineated on the basis of vegetation, embedded within the (complete) hydrogeomorphic unit, and defined as an area of wetland that is homogeneous in terms of opportunities for plant growth. At a broad scale, most ecosystem services can be superficially derived from the hydrogeomorphic unit type and the way water moves through a wetland, but habitat units and the plant species that define them would have a specific effect on the delivery of ecosystem services, for example, with different assemblages providing different resistance to flow. Some types of ecosystem services are exclusively linked to specific wetland habitats, especially provisioning services. For this reason, it is proposed that a combined approach of hydrogeomorphic classification together with a vegetation map, offers the maximum information value for ecosystem service determination. In order to account for the potential pitfall of “double counting” when combining the top-down and bottom-up approaches, each service needs to be considered individually with reference to the degree to which a service is either: (a) primarily determined by HGM class/attributes and modified by the vegetation class/attributes; or (b) primarily determined by the vegetation class/attributes. 相似文献
5.
Accurate and rapid characterization of influenza A virus (IAV) hemagglutinin (HA) and neuraminidase (NA) sequences with respect to subtype and clade is at the basis of extended diagnostic services and implicit to molecular epidemiologic studies. ClassyFlu is a new tool and web service for the classification of IAV sequences of the HA and NA gene into subtypes and phylogenetic clades using discriminatively trained profile hidden Markov models (HMMs), one for each subtype or clade. ClassyFlu merely requires as input unaligned, full-length or partial HA or NA DNA sequences. It enables rapid and highly accurate assignment of HA sequences to subtypes H1–H17 but particularly focusses on the finer grained assignment of sequences of highly pathogenic avian influenza viruses of subtype H5N1 according to the cladistics proposed by the H5N1 Evolution Working Group. NA sequences are classified into subtypes N1–N10. ClassyFlu was compared to semiautomatic classification approaches using BLAST and phylogenetics and additionally for H5 sequences to the new “Highly Pathogenic H5N1 Clade Classification Tool” (IRD-CT) proposed by the Influenza Research Database. Our results show that both web tools (ClassyFlu and IRD-CT), although based on different methods, are nearly equivalent in performance and both are more accurate and faster than semiautomatic classification. A retraining of ClassyFlu to altered cladistics as well as an extension of ClassyFlu to other IAV genome segments or fragments thereof is undemanding. This is exemplified by unambiguous assignment to a distinct cluster within subtype H7 of sequences of H7N9 viruses which emerged in China early in 2013 and caused more than 130 human infections. http://bioinf.uni-greifswald.de/ClassyFlu is a free web service. For local execution, the ClassyFlu source code in PERL is freely available. 相似文献
6.
The rapid growth of published cloud services in the Internet makes the service selection and recommendation a challenging task for both users and service providers. In cloud environments, software re services collaborate with other complementary services to provide complete solutions to end users. The service selection is performed based on QoS requirements submitted by end users. Software providers alone cannot guarantee users’ QoS requirements. These requirements must be end-to-end, representing all collaborating services in a cloud solution. In this paper, we propose a prediction model to compute end-to-end QoS values for vertically composed services which are composed of three types of cloud services: software (SaaS), infrastructure (IaaS) and data (DaaS) services. These values can be used during the service selection and recommendation process. Our model exploits historical QoS values and cloud service and user information to predict unknown end-to-end QoS values of composite services. The experiments demonstrate that our proposed model outperforms other prediction models in terms of the prediction accuracy. We also study the impact of different parameters on the prediction results. In the experiments, we used real cloud services’ QoS data collected using our developed QoS monitoring and collecting system. 相似文献
7.
In this paper, an autonomic performance management approach is introduced that can be applied to a general class of web services deployed in large scale distributed environment. The proposed approach utilizes traditional large scale control-based algorithms by using interaction balance approach in web service environment for managing the response time and the system level power consumption. This approach is developed in a generic fashion that makes it suitable for web service deployments, where web service performance can be adjusted by using a finite set of control inputs. This approach maintains the service level agreements, maximizes the revenue, and minimizes the infrastructure operating cost. Additionally, the proposed approach is fault-tolerant with respect to the failures of the computing nodes inside the distributed deployment. Moreover, the computational overhead of the proposed approach can also be managed by using appropriate value of configuration parameters during its deployment. 相似文献
8.
The National assessment of ecosystem services of Russia is an urgent task taking into account their key importance for maintaining the quality of life of the population and the regulation of biosphere processes. The purpose of the present paper is to propose a natural science methodology for evaluation supplied, demanded and consumed ecosystem services for national ecosystem assessment of Russia.Supplied ecosystem services were considered as services produced by ecosystems regardless of presence or absence of people, demanded – as the volume of services that is necessary for people and economy, consumed – as services actually used by people. Ratios between these three volumes of ecosystem services reveal the degree of service use and degree of meeting the demand for service that are analogous to indices of ecosystem service budget.The proposed methodology was tested in the preparation of the Prototype of the National Report on Ecosystem Services of Russia. Ecosystem services of air and water purification are considered as examples in the present paper.These examples demonstrate that proposed methodology is useful for estimation of surplus or deficit in ecosystem services across regions and identification of ecological risk areas. It also allows regional comparison at national level. 相似文献
9.
Many consumers participate in the smart city via smart portable gadgets such as wearables, personal gadgets, mobile devices, or sensor systems. In the edge computation systems of IoT in the smart city, the fundamental difficulty of the sensor is to pick reliable participants. Since not all smart IoT gadgets are dedicated, certain intelligent IoT gadgets might destroy the networks or services deliberately and degrade the customer experience. A trust-based internet of things (TM-IoT) cloud computing method is proposed in this research. The problem is solved by choosing trustworthy partners to enhance the quality services of the IoT edging network in the Smart architectures. A smart device choice recommendation method based on the changing networks was developed. It applied the evolutionary concept of games to examine the reliability and durability of the technique of trust management presented in this article. The reliability and durability of the trustworthiness-managing system, the Lyapunov concept was applied.A real scenario for personal-health-control systems and air-qualitymonitoring and assessment in a smart city setting confirmed the efficiency of the confidence-management mechanism. Experiments have demonstrated that the methodology for trust administration suggested in this research plays a major part in promoting multi-intelligent gadget collaboration in the IoT edge computer system with an efficiency of 97%. It resists harmful threads against service suppliers more consistently and is ideal for the smart world's massive IoT edge computer system. 相似文献
10.
With the development of web technologies and cloud computing, more and more services which provide similar functionality but differ in QoS are deployed on the Internet via cloud platforms. Recently, skyline analysis is adopted to select candidate services with better QoS to facilitate the process of QoS-aware service composition. However, the fast increasing number of services, multiple QoS attributes to be considered, and dynamic service environment pose a big challenge to skyline service selection. In this paper, we present a parallel skyline service selection method to improve the efficiency by upgrading the MapReduce paradigm. An angle-based dataspace partitioning approach is employed in our MapReduce based skyline service selection. In particular, we explore the dominance power of local skyline services to improve the efficiency of selection, and present two detailed algorithms. To handle the dynamic nature of service environment, we employ Paper-Tape (PT) model which is used to rapidly locate varying services, and present a dynamic skyline service selection algorithm based on PT model. By experimenting over both real and synthetical datasets, we demonstrate the efficiency of our proposed methods. 相似文献
11.
Cloud computing is becoming the new generation computing infrastructure, and many cloud vendors provide different types of cloud services. How to choose the best cloud services for specific applications is very challenging. Addressing this challenge requires balancing multiple factors, such as business demands, technologies, policies and preferences in addition to the computing requirements. This paper recommends a mechanism for selecting the best public cloud service at the levels of Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). A systematic framework and associated workflow include cloud service filtration, solution generation, evaluation, and selection of public cloud services. Specifically, we propose the following: a hierarchical information model for integrating heterogeneous cloud information from different providers and a corresponding cloud information collecting mechanism; a cloud service classification model for categorizing and filtering cloud services and an application requirement schema for providing rules for creating application-specific configuration solutions; and a preference-aware solution evaluation mode for evaluating and recommending solutions according to the preferences of application providers. To test the proposed framework and methodologies, a cloud service advisory tool prototype was developed after which relevant experiments were conducted. The results show that the proposed system collects/updates/records the cloud information from multiple mainstream public cloud services in real-time, generates feasible cloud configuration solutions according to user specifications and acceptable cost predication, assesses solutions from multiple aspects (e.g., computing capability, potential cost and Service Level Agreement, SLA) and offers rational recommendations based on user preferences and practical cloud provisioning; and visually presents and compares solutions through an interactive web Graphical User Interface (GUI). 相似文献
12.
As more and more manufacturing companies accumulate profits from service provision, the ability to monitor the adoption of the industrial services of other companies grows more important. The purpose of this paper is to propose a data-driven methodology for extraction of the industrial service portfolio from a company’s annual report. In this approach, form 10-K, a special format of annual report regulated by the Security Exchange Commission in United States is utilized as the data source. Because this document type contains rich information on a company’s operating segments, industrial service information is easily retrieved. Given the sheer volume of such documents, however, manual inspection is impractical. In order to resolve this issue, a text-mining algorithm is applied to automatically examine word-usage patterns and to identify the service portfolio. Then, the service portfolio’s relative position in the market is visualized on a positioning map. Due to the multi-dimensionality of the data, self-organizing map (SOM) is used as an alternative visualization scheme. SOM enables easy identification of the major service clusters as well as niche areas in the market; these, in turn, provide valuable information pertinent to service development planning. Also, and not least, policy makers can utilize our methodology to detect the servitization trends of various industries. 相似文献
13.
TMpro is a transmembrane (TM) helix prediction algorithm that uses language processing methodology for TM segment identification. It is primarily based on the analysis of statistical distributions of properties of amino acids in transmembrane segments. This article describes the availability of TMpro on the internet via a web interface. The key features of the interface are: (i) output is generated in multiple formats including a user-interactive graphical chart which allows comparison of TMpro predicted segment locations with other labeled segments input by the user, such as predictions from other methods. (ii) Up to 5000 sequences can be submitted at a time for prediction. (iii) TMpro is available as a web server and is published as a web service so that the method can be accessed by users as well as other services depending on the need for data integration. Availability: http://linzer.blm.cs.cmu.edu/tmpro/ (web server and help), http://blm.sis.pitt.edu:8080/axis/services/TMProFetcherService (web service). 相似文献
14.
科学地编制生态系统服务空间分布图,有助于识别生态系统优先保护热点及空缺,能够为国土安全规划提供基础信息。但由于缺乏统一科学的生态系统服务分级方法,生态系统服务分布图的展示效果和制图效率都受到限制。不恰当的分级制图会误导决策者对生态系统服务空间分布特征的判断,增加生态保护决策的不确定性。以构建生态服务制图分级标准为目标,对我国6个典型县区的土壤保持服务数据展开1:25万比例尺制图分级案例研究。采用分级精度、面积均衡性、极差一致性、空间自相关一致性4个分级质量评价指标评价并比较了目前地图编制中常用的自然断点法、几何间隔法、累积比例法、等差法、分位数法5种分级算法的分级制图效果。结果表明,6个县区有相似的土壤保持服务分布特征:低值区覆盖面积大,高值区覆盖面积小。各县区土壤保持服务制图最优分级方法有差异:延庆区、丰满区最优分级方法为自然断点法;永靖县、天山区、安宁市最优分级方法为累积比例法;富阳区最优分级方法为几何间隔法。各分级方法中,累积比例法在6个县区综合制图效果最优或接近最优,适用性最好,能够较好的刻画各县区的土壤保持服务空间分布特征。本文提出的分级评价方法及其结果,可为生态系统土壤保持服务制图规范化和自动化提供科学依据。 相似文献
15.
Existing ecological service assessments of urban green space have concentrated on natural environment, while research on the social services function remains underexplored. Taking Shenzhen as an example, this study starts with integrating the function of green space system with human needs. An indicator assessment technique that combines spatialization, rasterization and detailed of land ecological assessment was established with regard to the benefits of landscape aesthetics, function of disaster prevention and mitigation, and accessibility of park greenbelts. The results show that Shenzhen has very high recreational and cultural value, as the areas above medium level account for 66% of the city’s land area, and the recreational and cultural services are worth approximately 40.8million Yuan. Forest parks and comprehensive parks are important places to carry out social service function, particularly the disaster prevention and mitigation function, and the green spaces for disaster prevention and mitigation can be found in most of the disaster-prone areas. The accessibility of service shows a certain level of centrality, since the highest grade is concentrated in the central Bao’an, central Longgang, and the central part of the city. Based on the GIS overlay analysis, this study recognizes the distribution of essential patches, and constructs the structure of essential patches in urban green greenbelt systems by a combination of point, line, and surface elements. It shows the services of the Shenzhen greenbelt system have high potential for social integration, and this study also discusses the policy implication for macro decision-making. The assessment results objectively reflect multiple social services of the green space system in this region and provide a reference for the management, planning and construction of urban ecology in similar cities. 相似文献
16.
Background Life sciences make heavily use of the web for both data provision and analysis. However, the increasing amount of available
data and the diversity of analysis tools call for machine accessible interfaces in order to be effective. HTTP-based Web service
technologies, like the Simple Object Access Protocol (SOAP) and REpresentational State Transfer (REST) services, are today
the most common technologies for this in bioinformatics. However, these methods have severe drawbacks, including lack of discoverability,
and the inability for services to send status notifications. Several complementary workarounds have been proposed, but the
results are ad-hoc solutions of varying quality that can be difficult to use. 相似文献
17.
生态系统服务强调了生态组成要素对人类福祉贡献的服务功能特性,近年来逐渐成为生态学研究的热点。然而,如何从生态组成要素的综合格局——景观的服务角度阐述生态系统服务,仍然是当前研究的巨大挑战。本文详细介绍了景观服务的概念、分类和应用尺度,并从制图方法和评价指标两方面阐述了景观服务的定量化方法,在此基础上探讨了景观服务在规划设计中的应用问题。最后,提出了新的研究展望,即要继续完善景观服务概念及分类体系,探讨景观服务的多尺度相互影响机理,寻求有效的景观服务空间定量化制图方法,评价景观服务未来发展变化,探索多项景观服务间的相互影响机理以及系统的景观服务规划方法,以期为今后景观服务的应用研究提供方向性参考意见。 相似文献
18.
Due to the restrictions that most traditional scheduling strategies only cared about users’ quality of service (QoS) time or cost requirements, lacked the effective analysis of users’ real service demand and could not guarantee scheduling security, this paper added trust into workflow’s QoS target and proposed a novel customizable cloud workflow scheduling model. In order to better analyze different user’s service requirements and provide customizable services, the new model divided workflow scheduling into two stages: the macro multi-workflow scheduling as the unit of cloud user and the micro single workflow scheduling. It introduced trust mechanism into multi-workflow scheduling level. And in single workflow scheduling level, it classified workflows into time-sensitive, cost-sensitive and balance three types according to different workflow’s QoS demand parameters using fuzzy clustering method. Based on it, it customized different service strategies for different type. The simulation experiments show that the new schema has some advantages in shortening workflow’s final completion time, achieving relatively high execution success rate and user satisfaction compared to other kindred solutions. 相似文献
19.
BioMOBY is an Open Source research project which aims to generate an architecture for the discovery and distribution of biological data through web services; data and services are decentralised, but the availability of these resources, and the instructions for interacting with them, are registered in a central location called MOBY Central. BioMOBY adds to the web services paradigm, as exemplified by Universal Data Discovery and Integration (UDDI), by having an object-driven registry query system with object and service ontologies. This allows users to traverse expansive and disparate data sets where each possible next step is presented based on the data object currently in-hand. Moreover, a path from the current data object to a desired final data object could be automatically discovered using the registry. Native BioMOBY objects are lightweight XML, and make up both the query and the response of a simple object access protocol (SOAP) transaction. 相似文献
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