A formal mapping-based approach for distributed schedule coordination on projects

Construction projects involve a large number of participants with overlapping scope of work. Coordination of their activities is usually an iterative manual task undertaken by a general contractor that is often unaware of the detailed constraints of other participants. Project schedules play a key role in this coordination and form the backbone of almost all current approaches to process coordination. However, no single schedule represents the perspective of all participants involved in a project. Rather, each participant keeps in some manner a schedule for its own activities, resulting in multiple schedules that need to be coordinated. The current literature does not support simultaneous reasoning across multiple distributed, overlapping schedules. This paper introduces constructs to formalize the integration of participants’ overlapping schedules that represent the same project tasks, but use a different set breakdown structures and level of detail. Implementation of these constructs allows linking of the master schedule to the other participants’ schedules thereby representing the perspectives of all project participants. This integrated perspective facilitates initial schedule coordination and allows rapid identification of schedule conflicts in response to any schedule changes.     

Multi-agent Mediator architecture for distributed manufacturing

A generic Mediator architecture for distributed task planning and coordination has been developed using multi-agent paradigms. In this approach, agents function autonomously as independent computing processes, and dynamic virtual clusters coordinate the agent's activities and decision making. This coordination involves dynamically created coordination agents and resource agents concurrently. The Mediator architecture contains three levels of these coordination agents: the template mediator, the data-agent manager, and the active mediator. The template mediator is the top-level global coordinator. This agent contains both the templates and the cloning mechanism to create the successively lower-level agents. Task plans are decomposed successively into subtasks, which are allocated to dynamically created agent clusters coordinated through data-agent managers and active mediators. Coordination of agent activity takes place both among the clusters and within each cluster. The system dynamically adapts to evolving manufacturing tasks, with virtual agent clusters being created as needed, and destroyed when their tasks are completed. The mediator architecture and related mechanisms are demonstrated using an intelligent manufacturing scheduling application. Both the machines and the parts involved in this production system are considered as intelligent agents. These agents use a common language protocol based on the Knowledge Query Manipulation Language (KQML). The generic Mediator approach can be used for other distributed organizational systems beyond the intelligent manufacturing application it was originally developed for.     

DARGOS: A highly adaptable and scalable monitoring architecture for multi-tenant Clouds

One of the most important features in Cloud environments is to know the status and the availability of the physical resources and services present in the current infrastructure. A full knowledge and control of the current status of those resources enables Cloud administrators to design better Cloud provisioning strategies and to avoid SLA violations. However, it is not easy to manage such information in a reliable and scalable way, especially when we consider Cloud environments used and shared by several tenants and when we need to harmonize their different monitoring needs at different Cloud software stack layers. To cope with these issues, we propose Distributed Architecture for Resource manaGement and mOnitoring in cloudS (DARGOS), a completely distributed and highly efficient Cloud monitoring architecture to disseminate resource monitoring information. DARGOS ensures an accurate measurement of physical and virtual resources in the Cloud keeping at the same time a low overhead. In addition, DARGOS is flexible and adaptable and allows defining and monitoring new metrics easily. The proposed monitoring architecture and related tools have been integrated into a real Cloud deployment based on the OpenStack platform: they are openly available for the research community and include a Web-based customizable Cloud monitoring console. We report experimental results to assess our architecture and quantitatively compare it with a selection of other Cloud monitoring systems similar to ours showing that DARGOS introduces a very limited and scalable monitoring overhead.     

A software architecture for distributed organization management

In large organizations, management of large amounts of knowledge is a common problem. This knowledge is usually available in a distributed environment, in structured or non-structured form, and often is not exactly known where it is located and how to retrieve it in flexible ways. This paper describes an architecture to manage typical activities for an organization such as our University. During system analysis and specification, we had to collect a lot of information about structure and content of our organization, information available in various formats and media and not always automatically collectable. Hence, we designed a Document-based Software Architecture to support systems where formalization of information repositories, standardization of information location and management of every aspect involved in distributed contexts are crucial needs. We discuss if the configuration of a central-knowledge centered organization is the right solution or if it is better the choice of a distributed one. Since, all the documents managed in any organization are usually available in a structured way, we foresee a strong usage of XML documents and metadata standard definitions.     

A parallel architecture for distributed adaptive control

This paper describes the development of a flexible control system based on multiple T800 floating point transputers. In Part 1 of this paper, entitled 'The application of transputers to distributed control', an overview has been presented of distributed command and control systems (DCCS) and the suitability of the transputer for implementation within such systems discussed. In Part 2 of the article a transputer-based control module which has been developed at the University of Paisley is described. The module allows a number of different modes of operation in that it can be configured to act as either a fixed controller with the coefficients being down-loaded from a central control station, or as an adaptive controller which can make use of an explicit pole placement or linear quadratic Gaussian (LQG) structure. A supervisor, or coordination level, is incorporated into the adaptive controller to monitor the various parameters produced within the controller and direct the system to maintain a safe operation. This improves the applicability, robustness and integrity of the controller in real-time applications. The ease with which software tasks can be distributed over different transputer architectures allows the same software to be configured to accommodate between one and four transputers within the module. In this way the controller module can utilize a number of different transputer configurations depending on cost/performance trade-offs.The use of the transputer also allows the controller to communicate easily through its serial links with other controllers, hosts and external devices. In this way the module can be used as a universal controller node which can be easily incorporated into a large DCCS. Software has been developed to facilitate the production of this type of integrated environment such that a central network interface can initialize, analyse and supervise a number of the controller modules.     

A middleware architecture for distributed systems management

This paper presents a middleware solution for global management of any kind of distributed system, such as networks of PCs/workstations, clusters or server farms. Our approach lies in an object-oriented software architecture that models all kind of management information using the common information model (CIM) developed by the Distributed Management Task Force (DMTF). The classes and attributes obtained after the modeling process are mapped to a Lightweight Directory Access Protocol (LDAP) repository. This paper discusses the key features of our middleware that allows that any element (physical, logical, device, user or system) can be managed using a network-oriented and topology-independent approach. A representative example of management domain illustrates the procedures followed to build management applications using our middleware architecture.     

一种多租户授权管理访问控制模型

针对云服务中多租户应用面临越权访问和联合恶意攻击问题,综合聚类思想和基于密文策略的属性加密（CP-ABE）提出一种多租户授权管理访问控制模型（MTACM）。该模型根据多租户的业务特点将角色任务聚类为任务组,并采用匹配因子标记任务组,进而通过任务组授权管理角色属性,以实现角色的细粒度授权访问控制管理,减少系统计算量开销,降低系统的复杂度。在虚拟环境下实现了该模型算法,且通过逻辑推理证明了模型的安全性和系统访问的高效性。     

Challenges, approaches and architecture for distributed process integration in heterogeneous environments

Integration and coordination of distributed processes remains a central challenge of construction information technology research. Extant technologies, while capable, are not yet scalable enough to enable rapid customization and instantiation for specific projects. Specifically, the heterogeneity of existing legacy sources together with firms’ range of approaches to process management makes deployment of integrated information technologies impractical. This paper reports on an architecture for distributed process integration named process connectors that addresses heterogeneity in a scalable manner. The process connectors architecture incorporates two key approaches that address heterogeneity over varying time scales. The SEEK: Scalable Extraction of Enterprise Knowledge toolkit is reviewed as a mechanism to discover semantically heterogeneous source data. The SEEK approach complements existing data integration methods for persistent sharing of information. To make use of shared data on a per project basis, a schedule mapping approach is presented that integrates firms’ diverse individual schedules in a unified representation. The schedule mapping approach allows integration of process views that have different levels of detail, while allowing participants to maintain their own view of the process. Collectively, SEEK and the schedule mapping approach facilitate a broad range of analyses to support coordination of distributed schedules. While this paper focuses primarily on schedule process integration, the process connectors architecture is viewed as providing a broad solution to discovery and integration of firms’ process data.     

A deep recurrent Q network towards self-adapting distributed microservice architecture

One desired aspect of microservice architecture is the ability to self-adapt its own architecture and behavior in response to changes in the operational environment. To achieve the desired high levels of self-adaptability, this research implements distributed microservice architecture model running a swarm cluster, as informed by the Monitor, Analyze, Plan, and Execute over a shared Knowledge (MAPE-K) model. The proposed architecture employs multiadaptation agents supported by a centralized controller, which can observe the environment and execute a suitable adaptation action. The adaptation planning is managed by a deep recurrent Q-learning network (DRQN). It is argued that such integration between DRQN and Markov decision process (MDP) agents in a MAPE-K model offers distributed microservice architecture with self-adaptability and high levels of availability and scalability. Integrating DRQN into the adaptation process improves the effectiveness of the adaptation and reduces any adaptation risks, including resource overprovisioning and thrashing. The performance of DRQN is evaluated against deep Q-learning and policy gradient algorithms, including (1) a deep Q-learning network (DQN), (2) a dueling DQN (DDQN), (3) a policy gradient neural network, and (4) deep deterministic policy gradient. The DRQN implementation in this paper manages to outperform the aforementioned algorithms in terms of total reward, less adaptation time, lower error rates, plus faster convergence and training time. We strongly believe that DRQN is more suitable for driving the adaptation in distributed services-oriented architecture and offers better performance than other dynamic decision-making algorithms.     

A software architecture for distributed computer control systems

Distributed computer control systems have a number of potential advantages over centralized systems, especially where the application is itself physically distributed. A computer station can be placed close to the plant being controlled, and a communications network used to enable the stations to communicate to coordinate their actions. However, the software must be carefully designed to exploit the potential advantages of distribution. This paper describes the software architecture of CONIC, a system to support distributed computer control applications. This architecture emphasizes the distinction between the writing of individual software components and the construction and configuration of a system from a set of components. A modular structure is used to separate programming from configuration. Typed entry and exit ports are used to clearly define module interfaces. Ports, analagous to the plugs and sockets of hardware components, permit modules to be interconnected in different ways. On-line modification and extension of the system is supported by permitting the dynamic creation and interconnection of modules. Message passing primitives are provided to permit modules to coordinate and synchronize control actions.     

A distributed architecture for efficient Web service discovery

Although the definition of service-oriented architecture (SOA) included the presence of a service registry from the beginning, the first implementations (e.g., UDDI) did not really succeed mainly because of security and governance issues. This article tackles the problem by introducing DREAM (Distributed Registry by ExAMple): a publish/subscribe-based solution to integrate existing, different registries, along with a match-making approach to ease the publication and retrieval of services. DREAM fosters the interoperability among registry technologies and supports UDDI, ebXML Registry, and other registries. The publish/subscribe paradigm allows service providers to decide the services they want to publish, and requestors to be informed of the services that satisfy their interests. As for the match-making, DREAM supports different ways to evaluate the matching between published and required services. Besides presenting the architecture of DREAM and the different match-making opportunities, the article also describes the experiments conducted to evaluate proposed solutions.     

A distributed synchronization mechanism for interacting processes

Reliable synchronization is intended to ensure a graceful degradation of the system in the event of a failure. Solutions to synchronization problems of this kind under constant space conditions are presented. Lamport's bakery algorithm and generalized critical region have been modified and extended for application to this problem.     

A multi-agent architecture for supporting distributed normality-based intelligent surveillance

Intelligent surveillance involves the use of AI techniques to monitor environments whose analysis is becoming more and more complex because of the large number of sensors used and the need of monitoring multiple events of interest simultaneously. Most of the current surveillance systems provide solutions for particular problems but still suffer from lack of flexibility and scalability when they are used on different or related surveillance problems. To overcome this limitation, two aspects should be addressed: a knowledge-based surveillance model flexible enough to deal with different events of interest and an architecture that gives support to this model when deploying the surveillance system within a particular scenario. This paper discusses the architecture devised to deploy intelligent surveillance systems by means of a set of autonomous agents that are responsible for the management of different surveillance tasks and for cooperating to monitor complex environments. This multi-agent architecture is inspired by a normality-based formal model used to define the knowledge needed to analyze general-purpose surveillance concepts. We use the architecture to deploy a surveillance system to monitor an urban traffic scenario.     

A distributed architecture for supervision of autonomous multi-robot missions

Realizing long-term autonomous missions involving teams of heterogeneous robots is a challenge. It requires mechanisms to make robots react to disturbances or failures that will arise during the mission, while trying to successfully achieve the mission in cooperation. This paper presents HiDDeN, a distributed deliberative architecture that manages the execution of a hierarchical plan. This plan has initially been computed offline, ensuring some military operational constraints of the mission. Each robot’s supervisor then executes its own part of the plan, and reacts to failures using a hierarchical repair approach. This hierarchical repair has been designed with the sake of ensuring operational constraints, while reducing the need of communication between robots, as communication may be intermittent or even nonexistent when the robots operate in completely separate environments. HiDDeN’s robustness and scalability is evaluated with simulations. Experiments with an autonomous helicopter and an autonomous underwater vehicle have been realized and are presented as the defining point of our contribution.     

A distributed architecture for scalable private RFID tag identification

The fast growth of Radio Frequency IDentification (RFID) implies a deployment challenge, namely how to keep this technology scalable without renouncing security and privacy features. This paper focuses on combining tag privacy and scalability using the hash locks mechanism. Our contribution is twofold: (i) a cell-based architecture is proposed in which the readers co-operate in order to conduct tag identification in a private and scalable way; (ii) a communication protocol for the proposed architecture is defined and assessed. The proposed architecture and protocol solve the scalability shortcomings of private RFID identification pointed out by Juels and Weis.     

Silt: A distributed bit-parallel architecture for early vision

A new form of parallelism,distributed bit-parallelism, is introduced. A DBP organization distributes each bit of a data item to a different processor. DBP allows computation that is sublinear with word size for such operations as integer addition, arithmetic shifts, and data moves. The implications of DBP for system architecture are analyzed. An implementation of a DPB architecture based on a mesh with a fost-bypass network is presented, and the performance of DBP algorithms on this architecture is analyzed. The application of the architecture to early vision algorithms is discussed.     

基于SaaS模式公共服务平台多用户数据结构的研究

本文在研究SaaS模式特点的基础上,首先提出了SaaS应用的体系架构,然后提出了基于SaaS模式的企业公共服务平台的三个紧密相连的模型——多用户数据模型、元数据管理模型和安全服务模型.     

A distributed control architecture for an autonomous mobile robot

This paper describes a Distributed Control Architecture for an autonomous mobile robot. We start by characterizing the Conceptual Levels into which the various problem-solving activities of a mobile robot can be classified. In sequence, we discuss a Distributed Control System that provides scheduling and coordination of multiple concurrent activities on a mobile robot. Multiple Expert Modules are responsible for the various tasks and communicate through messages and over a Blackboard. As a testbed, the architecture of a specific system for Sonar-Based Mapping and Navigation is presented, and a distributed implementation is described.