1058760
Enabling network-aware applications
Many high-performance distributed applications use only a small fraction of their available bandwidth. A common cause of this problem is not a flaw in the application design, but rather improperly tuned network settings. Proper tuning techniques, such as setting the correct TCP buffers and using parallel streams, are well-known in the networking community, but outside this community they are infrequently applied. In this paper, we describe a service that makes the task of network tuning trivial for application developers and users. Widespread use of this service should virtually eliminate a common stumbling block for high-performance distributed applications.
1514436
Dynamic monitoring of high-performance distributed applications
Developers and users of high-performance distributed systems often observe performance problems such as unexpectedly low throughput or high latency. Determining the source of the performance problems requires detailed end-to-end instrumentation of all components, including the applications, operating systems, hosts, and networks. However, one must be very careful to design the instrumentation to have extremely low overhead, and not affect the system being monitored. In this paper we present a very light-weight instrumentation system that can be dynamically activated to unobtrusively collect and aggregate detailed end-to-end monitoring information from distributed applications. We also show how emerging "web services" can be used to facilitate remote interaction with this system.
10444660
A Monitoring Sensor Management System for Grid Environments
Large distributed systems such as Computational Grids require a large amount of monitoring data be collected for a variety of tasks such as fault detection, performance analysis, performance tuning, performance prediction, and scheduling. Ensuring that all necessary monitoring is turned on and that data is being collected can be a very tedious and error-prone task. We have developed an agent-based system to automate the execution of monitoring sensors and the collection of event data.
54356023
A monitoring sensor management system for grid environments
Large distributed systems, such as computational grids, require a large amount of monitoring data be collected for a variety of tasks, such as fault detection, performance analysis, performance tuning, performance prediction and scheduling. Ensuring that all necessary monitoring is turned on and that the data is being collected can be a very tedious and error-prone task. We have developed an agent-based system to automate the execution of monitoring sensors and the collection of event data.
9722973
Monitoring Data Archives for Grid Environments
Developers and users of high-performance distributed systems often observe performance problems such as unexpectedly low throughput or high latency. To determine the source of these performance problems, detailed end-to-end monitoring data from applications, networks, operating systems, and hardware must be correlated across time and space. Researchers need to be able to view and compare this very detailed monitoring data from a variety of angles. To address this problem, we propose a relational monitoring data archive that is designed to efficiently handle high-volume streams of monitoring data. In this paper we present an instrumentation and monitoring event archive service that can be used to collect and aggregate detailed end-to-end monitoring information from distributed applications. This archive service is designed to be scalable and fault tolerant. We also show how the archive is based on the "Grid Monitoring Architecture" defined by the Global Grid Forum.
1519617
Distributed parallel data storage systems: a scalable approach to high speed image servers
We have designed, built, and analyzed a distributed parallel storage system that will supply image streams fast enough to permit multi-user, “real-time”, video-like applications in a wide-area ATM network-based Internet environment. We have based the implementation on user-level code in order to secure portability; we have characterized the performance bottlenecks arising from operating system and hardware issues, and based on this have optimized our design to make the best use of the available performance. Although at this time we have only operated with a few classes of data, the approach appears to be capable of providing a scalable, high-performance, and economical mechanism to provide a data storage system for several classes of data (including mixed multimedia streams), and for applications (clients) that operate in a high-speed network environment.
17186964
A Ubiquitous Fashionable Computer with an i-Throw Device on a Location-Based Service Environment
The ubiquitous fashionable computer (UFC), introduced in this paper, is a wearable computer that allows people to exploit ubiquitous computing environment in a user-friendly manner. We present the design approach and philosophy of the UFC that is wearable, aesthetic, and intuitive. The UFC supports the interoperability of various communication interfaces among WLAN, Bluetooth and ZigBee devices. We developed a wireless gesture recognition device, called i -Throw, which is small enough to be worn on one's finger like a ring. The UFC, with the help of i -Throw, can control ubiquitous environment using an intuitive hand motion. To explain the practical use of the UFC platform and the user-friendly interaction with ubiquitous environment, we implemented a ubiquitous testbed where multiple UFC users interact with various ubiquitous devices or other UFC users. In addition, we implemented a practical application which makes it possible to exchange the various objects and control ubiquitous devices very easily.
11330211
Resolving References to Graphical Objects in Multimodal Queries by Constraint Satisfaction
In natural language queries to an intelligent multimodal system, ambiguities related to referring expressions - source ambiguities - can occur between items in the visual display and objects in the domain being represented. A multimodal interface has to be able to resolve these ambiguities in order to provide satisfactory communication with a user. In this paper, we briefly introduce source ambiguities, and present the formalisation of a constraint satisfaction approach to interpreting singular referring expressions with source ambiguities. In our approach, source ambiguities are resolved simultaneously with other referent ambiguities, allowing flexible access to various sorts of knowledge.
7999511
A proportional-share scheduler for multimedia applications
This paper presents a proportional-share CPU scheduler which can support multimedia applications in a general-purpose workstation environment. For this purpose, we have extended the stride scheduler which is designed originally for conventional tasks. New scheduling parameters are introduced to specify timing requirements of multimedia applications. Through the, use of the rate regulator, the accuracy error of the scheduling is reduced to O(1). Separate task groups are proposed to represent both relative shares and absolute shares. The proposed scheduler is evaluated using a simulation study. The results show that the proposed scheduler achieves improved accuracy and adaptability as well as fairness.
393666
DAS: Intelligent Scheduling Systems for Shipbuilding
Daewoo Shipbuilding Company, one of the largest shipbuilders in the world, has experienced great deal of trouble with the planning and scheduling of its production process. To solve the problems, from 1991 to 1993, Korea Advanced Institute of Science and Technology (KAIST) and Daewoo jointly conducted the Daewoo Shipbuilding Scheduling (das) Project. To integrate the scheduling expert systems for shipbuilding, we used a hierarchical scheduling architecture. To automate the dynamic spatial layout of objects in various areas of the shipyard, we developed spatial scheduling expert systems. For reliable estimation of person-hour requirements, we implemented the neural network-based person-hour estimator. In addition, we developed the paneled-block assembly shop scheduler and the long-range production planner. For this large-scale project, we devised a phased development strategy consisting of three phases: (1) vision revelation, (2) data-dependent realization, and (3) prospective enhancement. The DAS systems were successfully launched in January 1994 and are actively being used as indispensable systems in the shipyard, resulting in significant improvement in productivity and visible and positive effects in many areas.
16948552
Structured Circuit Semantics for Reactive Plan Execution Systems
A variety of reactive plan execution systems have been developed in recent years, each attempting to solve the problem of taking reasonable courses of action fast enough in a dynamically changing world. Comparing these competing approaches, and collecting the best features of each, has been problematic because of the diverse representations and (sometimes implicit) control structures that they have employed. To rectify this problem, we have extended the circuit semantics notion of teleo-reactive programs into richer, yet compact semantics, called structured circuit semantics (SCS), that can be used to explicitly represent the control behavior of various reactive execution systems. By transforming existing systems into SCS, we can identify underlying control assumptions and begin to identify more rigorously the strengths and limitations of these systems. Moreover, SCS provides a basis for constructing new reactive execution systems, with more understandable semantics, that can be tailored to particular domain needs.