The Internet of Things (IoT) has many important applications in multiple domains that include home automation, smart cities, healthcare, agriculture, and environment. IoT comprises a wide range of ...sensors and actuators that communicate with each other over cloud, fog, and edge level networks. Moreover, these devices use various communication protocols and are made by different manufactures. To deal with these diversities, IoT essentially needs interoperable communication interfaces among devices. Unfortunately, existing interoperability solutions are centralized and use fog or cloud level computing resources, making IoT communications latency-prone and poorly scalable. These issues could be handled effectively, if edge level devices could be made interoperable within the edge level and without needing fog or cloud level access. This article proposes a decentralized interoperability solution that stays fully within the edge level. The solution relies on controller devices that work on the interface boundaries of the edge devices. Unlike existing solutions, the proposed solution adopts a hierarchical interoperability model to handle interoperability at network, syntactical, semantic, and organizational levels. Our solution is nonproprietary, generic over vendors and platforms, and easily extendable to new devices. We compare our proposed solution with existing interoperability solutions for edge devices and show its mobility, efficiency, and flexibility.
Time delays in system states or control may result into unacceptable system operation or uncertainty in specialised technical systems like aircraft control, plant control, robotics etc. The issue of ...robustness, controllability, traceability, flexible management, reliability, and safety of such systems with time-delays, has been one of the primary research focuses of the last few decades. In parallel computing, different computing subunits share their tasks to balance loads to increase performance and throughput. In order to do so, subsystems have to communicate among themselves, adding further delay on top of existing system delay. It is possible to maintain performance and stability of the whole system, by designing observer for every subsystem in the system, overseeing the system state and compensating for existing time-delay. This paper reviews present literature to identify a linear time-delay system for load balancing and evaluates the stability and load balancing performance of the system with and without an observer. Stability is analysed in terms of oscillation in the system responses and performance is evaluated as the speed of load-balancing operation.
Different technologies have been emerged to address the issues of power consumption in digital communication. In CMOS technology, dynamic power accounts for 70%-90% of the total power dissipation and ...it largely depends on the representation of data and increases linearly with the switching activities (transition from logic level High to Low and vice versa). An efficient representation of data can minimise power consumption by reducing switching activities. In this paper, we have proposed an approach using genetic algorithm to optimise switching activities in the Huffman code for biological data compression. The performance of the approach has been evaluated by applying it to a set of biological datasets. The experiments yield that the proposed approach reduces the switching activity by 45.47% in the best case, by 36.45% in the average case, and by 16.42% in the worst case.
Dependability of safety-critical systems are a prime concern of the modern society due to the growing dependence on those systems. Safety of systems is a fundamental requirement for system ...reliability. Fault tree analysis (FTA) is powerful, well-established, and widely used tool for evaluating system safety. Fault trees provide a graphical and logical framework for analysing the dependability of systems. They have been successfully employed in studying the failure behaviour of a variety of real-world systems. In aquaculture, the volume of oxygen contained in water is considered as a critical parameter for the health and well-being of fishes. If oxygen levels drop below 4 mg/L then fishes may stop feeding, stressed and begin to die. Automated Pond Oxygen Management System (APOMS) is a critical component in aquaculture to maintain the proper oxygen level in water. In summer months, when oxygen level starts dropping due to increased temperature, then the APOMS can balance the oxygen level in water by generating oxygen artificially. Therefore, the failure of this system may result in a disastrous outcome. In this paper, we have used fault tree analysis to evaluate the reliability of an automated fault tolerant pond oxygen management system.
Freeman chain code with digits of unequal cost Kabir, Sohag; Azad, Tanzima; Ashraful Alam, A. S. M.
The 8th International Conference on Software, Knowledge, Information Management and Applications (SKIMA 2014),
12/2014
Conference Proceeding
Chain codes are the most size-efficient lossless compression methods for representing rasterised binary objects and contours. Satisfactory compression ratio, low processing cost and low storage ...requirements of the decoder make chain code technique interesting for storage and transmission of predefined graphical objects in embedded environments. Each element in the chain is encoded to show the relative angle difference between two adjacent pixels along the boundary of an object. The cost of binary bits representing the codes are considered to be equal. Yet, more efficient encoding is possible by considering and applying technique that treats the binary bits differently considering its requirement of storage space, energy consumption, speed of execution and etc. This paper considers cost of binary digits as unequal and proposes a new representation of the eight-direction Freeman chain code based on a variation of Huffman coding technique, which considers cost of bits as unequal. The evaluation and comparison of the cost efficiency between classical Freeman chain code and the new representation of the chain code is provided. Our experiments yield that the proposed representation of Freeman Chain code reduces overall storage/transmission cost of encoded objects considerably with compared to classical Freeman chain code.
Effects of unequal bit costs on classical Huffman codes Kabir, Sohag; Azad, Tanzima; Ashraful Alam, A. S. M. ...
2014 17th International Conference on Computer and Information Technology (ICCIT),
12/2014
Conference Proceeding
Classical Huffman codes have a very good compression performance over traditional systems. Yet, more efficient encoding is possible by considering and applying techniques that treat the binary bits ...differently considering requirement of storage space, energy consumption, speed of execution and so on. Future transmission systems are likely to be more efficient in many aspects. These systems will consume fewer resources to transmit or store one of the binary bits. Hence, an unequal bit cost would necessitate a different approach to producing an optimal encoding scheme. This work proposes an algorithm, which considers unequal bit-cost contribution to a message. Our experiment yields that the proposed algorithm reduces overall communication cost and improves compression ratio considerably in comparison to classical Huffman codes. This unequal bit cost technique produces a variant of Huffman Code that reduces total cost of the compressed message.
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