Workflow performance improvement using model-based scheduling over multiple clusters and clouds

In recent years, a variety of computational sites and resources have emerged, and users often have access to multiple resources that are distributed. These sites are heterogeneous in nature and performance of different tasks in a workflow varies from one site to another. Additionally, users typically have a limited resource allocation at each site capped by administrative policies. In such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources so that the workload is balanced among sites and the overhead is minimized in data transfer. Most existing systems either run the entire workflow in a single site or use naïve approaches to distribute the tasks across sites or leave it to the user to optimize the allocation of tasks to distributed resources. This results in a significant loss in productivity. We propose a multi-site workflow scheduling technique that uses performance models to predict the execution time on resources and dynamic probes to identify the achievable network throughput between sites. We evaluate our approach using real world applications using the Swift parallel and distributed execution framework. We use two distinct computational environments-geographically distributed multiple clusters and multiple clouds. We show that our approach improves the resource utilization and reduces execution time when compared to the default schedule.     

Poisoning the software supply chain

To the indiscriminate and opportunistic attacker, breaking into a software package's development and distribution site and waiting until unsuspecting users install it is more efficient than locating and hacking into users' systems individually. Starting in 2002 and continuing in to 2003, we've seen new emphasis on this type of attack. All the recent activity has showcased the trend that attacks against open-source software distribution sites are increasing. The author looks at how softwares distribution-both open source and proprietary-can invite attacks.     

A boundary condition based algorithm for locating construction site objects using RFID and GPS

Construction sites are rugged, dynamic, and complex, involving a large number of objects that continuously change their locations and occupied spaces. Being able to accurately locate and track site objects site is critical to project management and control to meet the increasing demands for efficiency and safety in modern construction projects. Automated locating technologies such as Radio Frequency Identification (RFID) have proven to be beneficial in tracking some construction site objects. The biggest challenge in applying the RFID technology is that the received signal strength (RSS) varies over time and location, and there is no direct relationship between signal strength and detection range, leading to low positional accuracies in the estimated tag locations. This paper presents an algorithm termed BConTri that combines a “boundary condition method” and the trilateration concept to estimate tag location in three-dimensional (3D) real world coordinates from four or more RFID readers equipped with GPS. This study also developed a prototype RFID locating system that implemented the newly created BConTri algorithm. A comprehensive assessment of the positional accuracy was applied to field experiment results and a high accuracy of the algorithm was observed. A measure of the spatial dilution of reader distribution was formulated and a linear relationship between this measure and the locating accuracy was observed, forming the base for using this measure as a reliable indicator for the resulting locating accuracy. This accuracy indicator helps in estimating the accuracy and quality control of RFID-based locating and tracking systems in construction.     

Protecting the consistency of workflow applications in collaborative development environments

Collaborative development environments allow a group of users to view and edit a shared item from geographically dispersed sites. Consistency maintenance in the face of concurrent accesses to shared entities is one of the core issues in the design of these systems. The paper introduces a lock based solution and three different algorithms that enable controlled, concurrent access to workflows for multiple application developers. Collaborative development of workflow applications promises better outcome in shorter time. The described method ensures that collaborators cannot break the consistency criteria of workflows by adding cycles or invalid edges to the graphs. A formal analysis of the three graph locking algorithms is also provided, focusing on the number of users who are allowed to edit a single workflow simultaneously. Based on the findings, a more powerful fourth graph locking algorithm is defined.     

Development of a Process-Based Model for Dynamic Interaction in Spatio-Temporal GIS

Spatial processes and their interactions are fundamental in explaining the complex behavior of real world systems. Current GIS describes space based on map layers and by means of either the vector or raster model. However, current vector and raster models cannot dynamically maintain topological relationships between spatial entities while these are changing rapidly in the real world. This makes current GIS incapable of modeling dynamic spatial processes. In this paper, the development of a process-based model is described. The model is developed based on spatial system theory and the Voronoi spatial model. First, the paper discusses spatial system theory, which forms the theoretical background for the model. Second, the Voronoi spatial model is adopted to describe spatial processes; it is more efficient than conventional vector and raster models. Third, the paper presents the capabilities of the model in one application.     

面向多中心数据的超图卷积神经网络及应用

近年来,图神经网络在神经性脑疾病诊断中的应用引起了广泛关注。然而,现有研究中使用的图通常只是基于简单的点对点连接,无法反映3个或更多受试者之间的复杂关联,尤其是在多中心数据集中,即由不同医疗机构所使用的不同采集设备和不同受试人群而集成的具有异质性的数据集。为解决医疗影像数据中存在的多中心异质性问题,提出了一种多中心超图数据结构来描述多中心数据之间的关系。这种超图由两种不同的超边构成,一种是描述单个中心内部关系的中心内超边,另一种是描述不同中心之间关系的跨中心超边。另外,还提出了一种超图卷积神经网络来学习节点的特征表示,这种超图卷积由两部分构成,第一部分是超图节点卷积,第二部分是超边卷积。在两个多中心数据集上的实验结果证明了所提方法的有效性。     

基于RDF4S语义服务描述模型的服务资源搜索框架

语义服务资源搜索是一个满足服务请求者快速、便捷地定位可用语义服务资源的过程。一个高效、精确的基于语义的语义服务资源搜索框架和经过精心设计并实现的搜索工具是语义服务框架中的一个必要组件。提出一种基于RDF4S语义服务描述模型的服务资源搜索框架,详细说明了该搜索框架的结构。搜索框架根据RDF4S语义服务描述模型的QoS、执行、功能和接口四种语义标注元素类型,分别采用不同的搜索匹配策略,可以很大程度上提高搜索的效率和精度。     

基于最优传输的多中心自闭症谱系障碍诊断

融合来自多个中心的医学数据能够增加样本数量，有助于研究自闭症谱系障碍(Autism spectrum disorder, ASD)的病理变化。因此，如何有效地利用多中心数据，提高对ASD诊断的准确性受到了越来越多的关注。然而，以往的大部分研究忽略了多中心数据的异质性(如受试者群体和扫描参数的不同)，这可能会降低模型在多中心数据上对疾病诊断的性能。为了解决这一问题，提出一种基于联合分布最优传输(Joint distribution optimal transport, JDOT)的领域自适应模型鉴别ASD。选择一个中心作为目标域，其余的中心作为源域，假设两个域的联合特征、标签空间分布之间存在非线性映射，利用最优传输方法交替优化传输矩阵和分类器。结果表明，在多中心静息态功能磁共振成像(resting state functional magnetic resonance imaging, rs-fMRI)数据上，该模型能够有效提高对ASD鉴别的准确性。     

Simulating a full screen of braille

A comparison is made between traditional embossed braille, which provides important information about page format, and speech, which presents information sequentially, thus losing page format information. Advances in technology have led to the advent of machines with dynamic braille displays which present the equivalent of a single line of embossed braille and which also provide computer access to blind users. These devices retain many of the advantages of embossed braille with added features such as editing flexibility. However, with speech-based systems, they do not present the user with the spatial relationships among the words on a page, the format information of a page layout, or the structure of columnar information. It was hypothesized that these format characteristics were important to locating information on a page, and that if these could be restored, the reader would operate more efficiently. A test apparatus was devised and a testing methodology was developed to test this thesis. The apparatus simulated a situation in which the reader utilized a single-line dynamic braille display mounted on a track so it could be moved vertically from line to line, much as one might move one's hands when scanning a page of embossed braille. This gives the reader direct feedback through arm location as to where he is reading on the page. Testing consisted of having subjects read sections of text and columnar information, and then respond by locating the answer in the text. It was discovered that physically scanning up and down the document allowed the users to develop a clearer sense of the overall gestalt of the page. Furthermore, readers were able to locate information using this technique approximately 80% faster than when using a single-line dynamic display which required the use of pushbuttons or a joystick to navigate around the page.     

Dynamics modeling and culling

The tools described, permit including large numbers of complex dynamic models in a VRML world easily and efficiently while maintaining high frame rates. We describe three tools that together provide an environment for authoring cullable, dynamic, rigid-body objects in VRML and Java: a code transformation tool that exploits approximations to dynamical systems to enable culling; a runtime layer generator, which defines a simple standard interface between a VRML browser and dynamical systems described in Java; a rigid-body modeler, which allows users to interactively design the runtime layer and preview the dynamic behavior. The article describes these tools, including some example systems, and discusses the runtime performance improvements obtained. Our tools are applicable if the spatial range of the dynamic model can be bounded by a static volume, the model is closed to outside influence, the underlying equations are continuous, and the dimension (number of degrees of freedom) of the system is small. Note that while the article focuses on VRML and Java as the target environment, the underlying techniques apply to any rendering and language environment     

A programming tool to generate multi-site daily rainfall using a two-stage semi parametric model

Many problems in hydrology and agricultural science require extensive records of rainfall from multiple locations. Temporal and/or spatial coverage of rainfall data is often limited, so that stochastic models may be required to generate long synthetic rainfall records. This study describes a multi-site rainfall simulator (MRS) to stochastically generate daily rainfall at multiple locations. The MRS is available as an open-source software package in the R statistical computing environment. The software includes statistical analysis and graphics functions, and can display statistics and graphs at multiple time scales, including from individual sites and areal averages. The MRS thus provides a detailed set of modelling functions to simulate and analyse daily rainfall. The capabilities of the package are demonstrated using 30 gauges located in Sydney, Australia, and the results show that the model preserves observed year-to-year variability, interannual persistence and various daily distributional and space–time dependence attributes.     

WESONet: Applying semantic web technologies and collaborative tagging to multimedia web information systems

The publication of different media types, like images, audio and video in the World Wide Web is getting more importance each day. However, searching and locating content in multimedia sites is challenging. In this paper, we propose a platform for the development of multimedia web information systems. Our approach is based on the combination between semantic web technologies and collaborative tagging. Producers can add meta-data to multimedia content associating it with different domain-specific ontologies. At the same time, users can tag the content in a collaborative way. The proposed system uses a search engine that combines both kinds of meta-data to locate the desired content. It will also provide browsing capabilities through the ontology concepts and the developed tags.     

On the combination of user-based and item-based collaborative filtering

In this paper, we propose two new filtering algorithms which are a combination of user-based and item-based collaborative filtering schemes. The first one, Hybrid-Ib, identifies a reasonably large neighbourhood of similar users and then uses this subset to derive the item-based recommendation model. The second algorithm, Hybrid-CF, starts by locating items similar to the one for which we want a prediction, and then, based on that neighbourhood, it generates its user-based predictions. We start by describing the execution steps of the algorithms and proceed with extended experiments. We conclude that our algorithms are directly comparable to existing filtering approaches, with Hybrid-CF producing favorable or, in the worst case, similar results in all selected evaluation metrics.     

Dynamic scheduling for multi-site companies: a decisional approach based on reinforcement multi-agent learning

In recent years, most companies have resorted to multi-site or supply-chain organization in order to improve their competitiveness and adapt to existing real conditions. In this article, a model for adaptive scheduling in multi-site companies is proposed. To do this, a multi-agent approach is adopted in which intelligent agents have reactive learning capabilities based on reinforcement learning. This reactive learning technique allows the agents to make accurate short-term decisions and to adapt these decisions to environmental fluctuations. The proposed model is implemented on a 3-tier architecture that ensures the security of the data exchanged between the various company sites. The proposed approach is compared to a genetic algorithm and a mixed integer linear program algorithm to prove its feasibility and especially, its reactivity. Experimentations on a real case study demonstrate the applicability and the effectiveness of the model in terms of both optimality and reactivity.     

Integration of CAD/CAm as seen from the production planners point of view

CAD/CAm is supposed to be one of the new tools to obtain increased productivity and flexibility in mechanical engineering. However, most of the existing systems are still far from satisfying the users with respect to “human-like” communication. Most of the systems are either CAD or CAM oriented. To reach a real step forward, integration and better user-communication is needed. One of the first tasks to be performed after the design phase is process planning. The purpose of this planning is to select processes and operations for an optimal production. This is a creative task and is therefore dependent on long experience and very skilled planners. The article describes process planning in general and communication with CAD in particular. Some new developments using an integrated product model are described.     

Extending the notion of a window system to audio

With audio's increasing importance in computer applications, users will soon need presentation, management and organizational capabilities similar to visual window systems to avoid a confusing cacophony of multiple audio sources sounding at once. The ways in which an audio window system could be used are described. These include multimedia documents, spatial data management systems, and teleconferencing. The signal processing methods used to create hierarchical and spatial distribution among nearly arbitrary (not pure sine wave) audio sources are discussed. A prototype system, combining hierarchical and spatial processing functions with a computer-controlled switch, software and human input devices, is presented. Two envisioned implementations, a terminal-based system and a network-based server, are described. Preliminary work suggests that an effective audio window system needs much less complexity and fewer levels of digital signal processing precision than the current prototype     

An efficient and accurate approach of circular object detection in color images

Object detection is a critical step of many image recognition systems. In this paper, we discuss the problem of circular shape object detection in still color images. An isotropic edge detector merged with spatial information and region based analysis is employed to extract image edge and obtain accurate gradient information of edge pixels, which assures the high accuracy of the subsequent circle detection. Then three circle parameters are estimated efficiently with only one 2-dimensional accumulator array and one 1-dimensional accumulator array, which greatly reduces the storage requirements and time complexity of our approach. Experimental results show that our method is robust in locating objects with complete or incomplete or concentric circle boundary in real color images without any prior knowledge.     

A novel rating prediction method based on user relationship and natural noise

Rating prediction is a hot spot in the research of recommender systems. There are lots of methods in this field such as collaborative filtering. However, few of these approaches take users’ friendship relationships into consideration, which actually contain significant information for rating prediction. Besides, there exists natural noise in users’ ratings. In this paper, we propose a rating prediction algorithm named NF-SVM based on the analysis of users’ natural noise and relationships. We cluster users to sharpen the similarity attribute among users, and use an iterative algorithm to obtain the rank of users’ rating quality. Then, we analyze users’ rating history to obtain the attributes of users’ natural noise. All these attributes are used to build a training set for SVM to get a prediction model. We also tested our algorithm in a data set which is crawled down from Douban, one of the largest movie rating web sites in China. Then we compared our algorithm with other state-of-the-art rating prediction methods. Extensive experiments show that our algorithm outperforms the other algorithms.     

Linking GIS and water resources management models: an object-oriented method

Many challenges are associated with the integration of geographic information systems (GISs) with models in specific applications. One of them is adapting models to the environment of GISs. Unique aspects of water resource management problems require a special approach to development of GIS data structures. Expanded development of GIS applications for handling water resources management analysis can be assisted by use of an object oriented approach. In this paper, we model a river basin water allocation problem as a collection of spatial and thematic objects. A conceptual GIS data model is formulated to integrate the physical and logical components of the modeling problem into an operational framework, based on which, extended GIS functions are developed to implement a tight linkage between the GIS and the water resources management model. Through the object-oriented approach, data, models and users interfaces are integrated in the GIS environment, creating great flexibility for modeling and analysis. The concept and methodology described in this paper is also applicable to connecting GIS with models in other fields that have a spatial dimension and hence to which GIS can provide a powerful additional component of the modeler’s tool kit.