Amir-Mohammad Rahmani

EDXY - A low cost congestion-aware routing algorithm for network-on-chips

In this paper, an adaptive routing algorithm for two-dimensional mesh network-on-chips (NoCs) is presented. The algorithm, which is based on Dynamic XY (DyXY), is called Enhanced Dynamic XY (EDXY). It is congestion-aware and more link failure tolerant compared to the DyXY algorithm. On contrary to the DyXY algorithm, it can avoid the congestion when routing from the current switch to the destination whose X position (Y position) is exactly one unit apart from the switch X position (Y position). This is achieved by adding two congestion wires (one in each direction) between each two cores which indicate the existence of congestion in a row (column). The same wires may be used to alarm a link failure in a row (column). These signals enable the routing algorithm to avoid these paths when there are other paths between the source and destination pair. To assess the latency of the proposed algorithm, uniform, transpose, hotspot, and realistic traffic profiles for packet injection are used. The simulation results reveal that EDXY can achieve lower latency compared to those of other adaptive routing algorithms across all workloads examined, with a 20% average and 30% maximum latency reduction on SPLASH-2 benchmarks running on a 49-core CMP. The area of the technique is about the same as those of the other routing algorithms.

Smart e-Health Gateway: Bringing intelligence to Internet-of-Things based ubiquitous healthcare systems

There have been significant advances in the field of Internet of Things (IoT) recently. At the same time there exists an ever-growing demand for ubiquitous healthcare systems to improve human health and well-being. In most of IoT-based patient monitoring systems, especially at smart homes or hospitals, there exists a bridging point (i.e., gateway) between a sensor network and the Internet which often just performs basic functions such as translating between the protocols used in the Internet and sensor networks. These gateways have beneficial knowledge and constructive control over both the sensor network and the data to be transmitted through the Internet. In this paper, we exploit the strategic position of such gateways to offer several higher-level services such as local storage, real-time local data processing, embedded data mining, etc., proposing thus a Smart e-Health Gateway. By taking responsibility for handling some burdens of the sensor network and a remote healthcare center, a Smart e-Health Gateway can cope with many challenges in ubiquitous healthcare systems such as energy efficiency, scalability, and reliability issues. A successful implementation of Smart e-Health Gateways enables massive deployment of ubiquitous health monitoring systems especially in clinical environments. We also present a case study of a Smart e-Health Gateway called UTGATE where some of the discussed higher-level features have been implemented. Our proof-of-concept design demonstrates an IoT-based health monitoring system with enhanced overall system energy efficiency, performance, interoperability, security, and reliability.

End-to-end security scheme for mobility enabled healthcare Internet of Things

We propose an end-to-end security scheme for mobility enabled healthcare Internet of Things (IoT). The proposed scheme consists of (i) a secure and efficient end-user authentication and authorization architecture based on the certificate based DTLS handshake, (ii) secure end-to-end communication based on session resumption, and (iii) robust mobility based on interconnected smart gateways. The smart gateways act as an intermediate processing layer (called fog layer) between IoT devices and sensors (device layer) and cloud services (cloud layer). In our scheme, the fog layer facilitates ubiquitous mobility without requiring any reconfiguration at the device layer. The scheme is demonstrated by simulation and a full hardware/software prototype. Based on our analysis, our scheme has the most extensive set of security features in comparison to related approaches found in literature. Energy-performance evaluation results show that compared to existing approaches, our scheme reduces the communication overhead by 26% and the communication latency between smart gateways and end users by 16%. In addition, our scheme is approximately 97% faster than certificate based and 10% faster than symmetric key based DTLS. Compared to our scheme, certificate based DTLS consumes about 2.2 times more RAM and 2.9 times more ROM resources. On the other hand, the RAM and ROM requirements of our scheme are almost as low as in symmetric key-based DTLS. Analysis of our implementation revealed that the handover latency caused by mobility is low and the handover process does not incur any processing or communication overhead on the sensors.

A Novel Synthetic Traffic Pattern for Power/Performance Analysis of Network-on-Chips Using Negative Exponential Distribution

In this paper, we present an empirically-derived synthetic traffic model based on the Negative Exponential Distribution (NED) for homogenous and heterogeneous Network-on-chips (NoCs) with any dimensionality. Compared to conventional synthetic traffic profiles, this synthetic traffic profile accurately captures key statistical behavior of realistic traces obtained by running different applications on Network-on-chips. To assess the usefulness of this new NoC traffic model, the average packet hops for the proposed traffic profile is compared with those of some synthetic and realistic traffic patterns. The results show that the NED traffic profile has more similarity with the realistic traffic profiles than those of conventional synthetic ones. Adding this traffic profile to the existing profiles, improves the design and characterization of NoCs.

Fog Computing in Healthcare Internet of Things: A Case Study on ECG Feature Extraction

Internet of Things technology provides a competent and structured approach to improve health and wellbeing of mankind. One of the feasible ways to offer healthcare services based on IoT is to monitor humans health in real-time using ubiquitous health monitoring systems which have the ability to acquire bio-signals from sensor nodes and send the data to the gateway via a particular wireless communication protocol. The real-time data is then transmitted to a remote cloud server for real-time processing, visualization, and diagnosis. In this paper, we enhance such a health monitoring system by exploiting the concept of fog computing at smart gateways providing advanced techniques and services such as embedded data mining, distributed storage, and notification service at the edge of network. Particularly, we choose Electrocardiogram (ECG) feature extraction as the case study as it plays an important role in diagnosis of many cardiac diseases. ECG signals are analyzed in smart gateways with features extracted including heart rate, P wave and T wave via a flexible template based on a lightweight wavelet transform mechanism. Our experimental results reveal that fog computing helps achieving more than 90% bandwidth efficiency and offering low-latency real time response at the edge of the network.

Congestion aware, fault tolerant, and thermally efficient inter-layer communication scheme for hybrid NoC-bus 3D architectures

Three-dimensional IC technology offers greater device integration and shorter interlayer interconnects. In order to take advantage of these attributes, 3D stacked mesh architecture was proposed which is a hybrid between packet-switched network and a bus. Stacked mesh is a feasible architecture which provides both performance and area benefits, while suffering from inefficient intermediate buffers. In this paper, an efficient architecture to optimize system performance, power consumption, and reliability of stacked mesh 3D NoC is proposed. The mechanism benefits from a congestion-aware and bus failure tolerant routing algorithm called AdaptiveZ for vertical communication. In addition, we hybridize the proposed adaptive routing with available algorithms to mitigate the thermal issues by herding most of the switching activities closer to the heat sink. Our extensive simulations with synthetic and real benchmarks, including the one with an integrated video-conference application, demonstrate significant power, performance, and peak temperature improvements compared to a typical stacked mesh 3D NoC.

Research and practices on 3D networks-on-chip architectures

To continue the growth of the number of transistors on a chip, the 3D IC practice, where multiple silicon layers are stacked vertically, is emerging as a revolutionary technology. Partitioning a larger die into smaller segments and then stacking them in a 3D integration can significantly reduce latency and energy consumption. Such benefits emanate from the notion that inter-wafer distances are negligible compared to intra-wafer distances which substantially reduce global wiring length in 3D chips. This progress has introduced novel architectures and new challenges for high-performance power-aware design exploration. In this paper, we outline the opportunities and challenges associated with three-dimensional networks-on-chip architectures, under consideration for different design metrics. In this context, we categorize and present several alternatives for 3D NoC architectures and we investigate and summarize the impact of these architectures on various system characteristics.

SEA: A Secure and Efficient Authentication and Authorization Architecture for IoT-Based Healthcare Using Smart Gateways☆

In this paper, a secure and efficient authentication and authorization architecture for IoT-based healthcare is developed. Security and privacy of patients’ medical data are crucial for the accepta ...

Design and management of high-performance, reliable and thermal-aware 3D networks-on-chip

Increasing the number of cores over a 2D plane is not efficient in hyper-core systems due to long interconnects. As a viable alternative over the 2D planar chip, 3D integrated technology offers greater device integration and shorter interlayer interconnects. 3D networks-on-chip (NoC)–bus hybrid mesh architecture, which is a hybrid between packet-switched network and a bus, was proposed to take advantage of the intrinsic attributes of 3D ICs. Even though this architecture was proposed as a feasible one to provide both performance and area benefits, the challenges of combining both media (NoC and bus) to design 3D NoCs have not been addressed. In this study, an efficient 3D NoC architecture is proposed to optimise performance, power consumption and reliability of 3D NoC–bus hybrid mesh system. The mechanism benefits from a congestion-aware and bus failure tolerant routing algorithm called ‘AdaptiveZ’ for vertical communication. In addition, the authors propose thermal-aware scheduling strategy in order to mitigate temperature by herding most of the switching activity closer to the heatsink. To estimate the efficiency of the proposed architecture, the system has been simulated using uniform, hotspot 10% and negative exponential distribution traffic patterns. In addition, a videoconference encoder has been used as a real application for system analysis. Compared with a typical stacked mesh 3D NoC, our extensive simulations demonstrate significant power, performance and peak temperature improvements.

Negative Exponential Distribution Traffic Pattern for Power/Performance Analysis of Network on Chips

In this paper, we propose a synthetic traffic model based on Negative Exponential Distribution (NED). This synthetic traffic profile is more similar to some statistical behavior of realistic traces obtained by running different applications on Network-on-chips that those of conventional synthetic traffic profiles. To assess usefulness of this traffic model, the average packet hops for the proposed traffic profile is compared with those of some synthetic and realistic traffic patterns obtained from running applications on NoCs. The results show that the NED traffic profile has more similarity with the realistic traffic profiles than those of conventional synthetic ones.