Location tracking in a personal communications services (PCS) network requires location update and paging. These procedures incur a large signaling cost as the demand for these services increases. In a location update...
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Location tracking in a personal communications services (PCS) network requires location update and paging. These procedures incur a large signaling cost as the demand for these services increases. In a location update process, the mobile terminal (MT) registers with the system when it enters into a new location area (LA) that contains many cells. In a paging process, the network system initiates a search process to find the mobile terminal to deliver an incoming call. A heuristic location tracking strategy is proposed based on location probability models that aims to reduce the signaling cost involved in paging process under delay bounds. Numerical results demonstrate that this paging strategy performs better than other methods [W. Wang et al., (2001)] for both uniform and non-uniform location probability distributions.
In this paper, a novel wireless load-sharing controller for parallel connected UPS inverters is proposed. As opposed to the conventional droop method, the proposed method achieves stable steady-state frequency and amp...
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This paper describes a comprehensive prototype of large-scale fault adaptive embedded software developed for the proposed Fermilab BTeV high energy physics experiment. Lightweight self-optimizing agents embedded withi...
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Reconfiguration and self-adaptation are vital capabilities of sensor networks and networked embedded systems that are required to operate in dynamic environments. This paper presents an approach for software reconfigu...
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Reconfiguration and self-adaptation are vital capabilities of sensor networks and networked embedded systems that are required to operate in dynamic environments. This paper presents an approach for software reconfiguration based on exploration of the design space of the application. The design space is represented by formally modeling all the software components, their alternative implementations and their interactions. Reconfiguration is triggered by monitoring the system and is performed by transitioning to a new configuration that satisfies the system constraints. The approach is demonstrated using experimental results for a representative tracking application.
In this paper we present the design of the rule-based framework for the runtime management of high-performance parallel scientific applications. The framework addresses the formulation of application management behavi...
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In this paper we present the design of the rule-based framework for the runtime management of high-performance parallel scientific applications. The framework addresses the formulation of application management behaviors as reaction rules, the injection of rules at runtime, their correct, efficient and scalable parallel enforcement, and the detection and resolution of rule conflicts. Unlike rule-based frameworks in business management and security and resource management domains, the presented framework focuses on high-performance parallel scientific applications, which require consistent and efficient management across processors and components. The framework is part of the Accord programming system (Liu et al., 2004)
Program affordability needs to be built-in at the initial concept formulation stage. For NASA's space exploration vision this is critical for long range sustainability of human presence in space. What is often ove...
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ISBN:
(纸本)1563477270
Program affordability needs to be built-in at the initial concept formulation stage. For NASA's space exploration vision this is critical for long range sustainability of human presence in space. What is often overlooked in the initial concept formulation of a large scale system endeavor such as NASA's Constellation program is the hidden cost of maintaining requisite operational safety margins and redundancy through adequate supply chain logistics. Ensuring adequate supply chain logistics necessitates the integration of operations and maintenance cycles. What enables this integration is the coordination and reconciliation across multiple equipment types of system health features and logistical information such as: (1) prognostic drivers from Integrated Vehicle Health Monitoring (IVHM) systems producing proactive condition-based "maintain me" demands, (2) maintenance management systems tracking usage and producing scheduled maintenance demands, (3) unscheduled maintenance demands resulting from any trouble reports entered by human observers of conditions missed by the IVHM system, and (4) implicit maintenance demands resulting from mission plans which require assignment of vehicular/robotic assets and consequently require assurance of the assigned assets' fitness for the intended tasks. In this paper we discuss how Coordinated Multi-source Maintenance on Demand (CMMD) technology, which is being is transitioned to the USMC Coherent Analytical Computing Environment (CACE) program and the Joint Strike Fighter Program, can be applied to the NASA domain, and its benefits in terms of mission affordability, operations efficiency and system health effectiveness. Using concepts derived from CMMD, we discuss the kind of IVHM capabilities needed to optimize multiple, parallel, yet inter-linked, operations-maintenance cycles, thereby optimizing program affordability while meeting specific mission supportability requirements across a broad range of mission scenarios.
Formal specification languages are often perceived as difficult to use by practitioners, and are therefore rarely-used in industrial software development practices. Numerous researchers have developed specification pa...
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Formal specification languages are often perceived as difficult to use by practitioners, and are therefore rarely-used in industrial software development practices. Numerous researchers have developed specification pattern systems to facilitate the construction of formal specifications of system properties. Feedback indicates that these patterns are considered helpful, but many practitioners prefer capturing properties using informal notations, such as natural language, instead of formal specification languages. This paper describes a project that addresses this technology gap. First, we introduce a stepwise process for deriving and instantiating system properties in terms of their natural language representations. The key components of this process are structured natural language grammars and specification pattern systems. Second, we describe SPIDER, a prototype implementation of a tool suite supporting this specification process. We illustrate the use of our approach with a description of a stepwise construction process of property specifications of a real-world automotive embedded system using Spider.
Reprogramming of sensor networks is an important and challenging problem as it is often necessary to reprogram the sensors in place. In this paper, we propose a multihop reprogramming service designed for Mica-2/XSM m...
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Reprogramming of sensor networks is an important and challenging problem as it is often necessary to reprogram the sensors in place. In this paper, we propose a multihop reprogramming service designed for Mica-2/XSM motes. One of the problems in reprogramming is the issue of message collision. To reduce the problem of collision and hidden terminal problem, we propose a sender selection algorithm that attempts to guarantee that in a neighborhood there is at most one source transmitting the program at a time. Further, our sender selection is greedy in that it tries to select the sender that is expected to have the most impact. We also use pipelining to enable fast data propagation. MNP is energy efficient because it reduces the active radio time of a sensor node by putting the node into "sleep" state when its neighbors are transmitting a segment that is not of interest. Finally, we argue that it is possible to tune our service according to the remaining battery level of a sensor, i.e., it can be tuned so that the probability that a sensor is given the responsibility of transmitting the code is proportional to its remaining battery life
Mobile medical applications have the capacity to provide services for patients and healthcare professionals regardless of time or place. The aim of this paper is to explore the current status of mobile, wireless and w...
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Mobile medical applications have the capacity to provide services for patients and healthcare professionals regardless of time or place. The aim of this paper is to explore the current status of mobile, wireless and wearable technological applications within the medical environment. After conducting a literature review on the availability of mobile, wireless and wearable computing applications within medicine, a summary of their purpose, features and functions was conceptually mapped to the Gibson and Nolan (1974) Stages of Growth Framework. Findings from the literature, the mapping process and limitations for growth are discussed within each of the technology categories. Limitations and challenges of development are highlighted and suggestions are made for future research.
computersystems hosting critical e-commerce applications must typically satisfy stringent quality-of-service (QoS) requirements under dynamic operating conditions and workloads. Also, as such systems increase in size...
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