On-line data validation in distributed data fusion

Abstract

Data acquisition and data fusion systems are becoming increasingly complex, being in fact systems of systems, where every component may be a system with varying levels of autonomy by themselves. Possible changes in system configuration by entities joining or being removed from the system make the system complex. As synchronous operation cannot be expected in such a system configuration, the temporal and spatial correctness of data must be achieved via other means. This paper presents the concept of mediated interactions as a method for ensuring correctness of computation in a distributed system. The mediator associated with each computing entity is responsible for online checking of the data both before it is sent out at the sender side and before it is received at the receiver side, ensuring that only data satisfying the validity constraints of the receiver-side data processing algorithm is used in computation. This assumes that each data item is augmented with metadata, which enables online data validation. The validity and quality dimensions in use depend on the system requirements defined by a specific problem and situational context; they may be temporal, spatial and involve various data quality dimensions, such as accuracy, confidence, relevance, credibility, and reliability. Among other capabilities, the mediator is able to cope with the unknowns in the temporal dimension that occur at runtime and are not predictable, such as channel delay, jitter of clocks and processing delays. This capability becomes an especially relevant factor in multi-tasking systems and in configurations in which a computing entity may have to process a variable number of parallel streams of data.Both the architecture and a simulation case study of a distributed data fusion scenario are presented in the paper.

Comprehensive Observation and its Role in Self-Awareness; An Emotion Recognition System Example

“…In some works such as [15], [16], [11], it is a cooperative or emerging behavior of the group of agents or subsystems. Nevertheless, attention and context-aware observation play a very important role in creating self-awareness.…”

“…Nevertheless, attention and context-aware observation play a very important role in creating self-awareness. Preden et al [15] describe the concept of context-awareness under situation-awareness which consists of values and interpretations of a set of situation parameters. Situation parameters represent properties of a situation, processed and abstracted independently.…”

Data to decision: pushing situational information needs to the edge of the network

“…Building upon the situation awareness model introduced by Endsley [8] we have proposed a situation awareness model for a distributed computing system in [10]. The diagram in Figure 4 illustrates how the sensor data as well as the intermediary situational information computation results (situation parameters) can be exchanged with other systems.…”

“…The proactive middleware ProWare [10] is used to realize the interactions between the individual systems making up the ISR SoS. ProWare relies on the concept of data mediators (ProWare components located on very system that is part of the ISR SoS) to ensure the correctness of data and the resilience of the SoS.…”

“…These constraints are observed both by the producer mediators before the data is communicated from the producer to the consumer. In a similar way the mediator component at the consumer side validates that the data received (still) satisfies the (temporal, spatial and others) constraints specified by the consumer process [10]. The ProWare mediator configuration and data exchange setup is depicted below in Figure 5.…”