Hakim Mellah - Academia.edu (original) (raw)

Papers by Hakim Mellah

IEEE internet of things magazine, Mar 1, 2023

IEEE Access

This paper presents a privacy-preserving proof of concept for assessing human behavior in emergen... more This paper presents a privacy-preserving proof of concept for assessing human behavior in emergency scenarios using aggregated data from multiple WiFi access points. The proposed method focuses on preserving individual privacy by avoiding tracking and metadata analysis, while still achieving effective multi-user activity recognition. To implement our approach, raw data from the Eduroam WiFi network at Polytechnique Montreal was collected and analyzed using standard supervised and anomaly detection techniques. The initial test was on recognizing patterns of academic activity, serving as the foundation for our investigation. Subsequently, the same methodology was applied during an evacuation drill scenario to recognize anomaly situations. Through our research, we demonstrate the potential to assess human situations effectively while safeguarding privacy, providing a critical capability for the early detection of emergency situations.

arXiv (Cornell University), Feb 17, 2020

5G is being designed as a common platform where multiple vertical applications will be able to co... more 5G is being designed as a common platform where multiple vertical applications will be able to co-exist and grow in a seamless manner. The diversity of the vertical requirements as well as the particular features of the 5G network itself, make it a real challenge to be able to assess or predict applications performance for those verticals. In this paper we motivate the fact that because of the very nature of verticals and 5G infrastructure, measurements alone will not be sufficient for application performance monitoring and prediction. We then propose a comprehensive framework to integrate those measurements in a simulation setting, presenting the key features and current roadblocks for an end-to-end wide-spread implementation.

IEEE Internet of Things Journal

Abstract: 2D object shape description has gained considerable attention in field of content-based... more Abstract: 2D object shape description has gained considerable attention in field of content-based image retrieval (CBIR) and in various applications that concerned with the shapes of objects. Object shape descriptors in the literature are commonly classified into two forms: contour-based and regionbased. In this paper we present our contour-based shape representation and description, where the object shape is represented and describe as a set of discrete segments. The descriptor is invariant to translation, scale and Circular shifting makes it robust to rotation. Key words: CBIR, image retrieval, shape descriptor, shape representation and description

Abstract: Wavelength Division Multiplexing (WDM) is a promising solution for data transport in fu... more Abstract: Wavelength Division Multiplexing (WDM) is a promising solution for data transport in future all-optical wide area networks. Such networks consist of fibers joined by dynamically controllable cross-connects which provide purely optical transport between pairs of network access stations. Optical packet switching (OPS) is optical switching with the finest granularity. Incoming packets are switched all-optically without being converted to electrical signal. There are two categories of OPS networks. Slotted (synchronous) OPS networks, in which all the packets have the same size and unslotted (asynchronous) OPS networks, where packets may or may not have the same size. In this study we propose to integrate MPLS over slotted OPS networks by aggregating optical packets into a labeled optical burst. The burst has a fixed number of packets (segments). The number of segments in each burst is encoded in the experimental field of the MPLS header.

This work proposes solutions to address two critical issues in synchronous OPS networks: contenti... more This work proposes solutions to address two critical issues in synchronous OPS networks: contention resolution and physical limitations. For the first issue, a novel switch node structure designed for contention resolution in synchronous OPS network is proposed.

Mode division multiplexing (MDM) over few mode fiber (FMF) has been proposed as an alternative so... more Mode division multiplexing (MDM) over few mode fiber (FMF) has been proposed as an alternative solution to tackle the capacity limitations of optical networks based on standard single mode fiber (SMF). These limitations are caused by the fiber nonlinear effects. MDM is realized through excitation of different fiber spatial modes, each mode being an independent transmission channel. Therefore, MDM over FMF requires mode conversion (basically from fundamental mode to higher order modes and vice versa) as well as mode multiplexing and demultiplexing. Mode conversion, multiplexing and demultiplexing can be realized through different techniques. It can be achieved using free-space optics based on matching the profile of an input mode to the profile of an output mode using phase mask or spatial light modulator. Mode conversion and (de)multiplexing can also be achieved using waveguide structures. These mode converters and (de)multiplexers are mainly based on optical fiber and planar wavegu...

2021 IEEE 4th 5G World Forum (5GWF), 2021

With the large scale deployment of 5G, more and more sophisticated applications will also be set ... more With the large scale deployment of 5G, more and more sophisticated applications will also be set out. In order to assess network performance, the networking behaviour of those applications should be evaluated beforehand, opening the need for 5G simulation. While many applications are confined to single base station coverage, others, such as the ones related to mobility, smart cities or smart grids, are geographically distributed. Therefore, in order to assess the overall performance of those applications, and, eventually, infer the user quality of experience (QoE), a large-scale simulator is needed. In this paper we present our experience in building of a realistic large-scale 5G network simulator that covers the whole island of Montreal. Milestones, roadblocks, limitations and future enhancements are also discussed.

2021 IEEE/ACM 25th International Symposium on Distributed Simulation and Real Time Applications (DS-RT), 2021

When using parallel computing to run large-scale simulations, the parts of the system being simul... more When using parallel computing to run large-scale simulations, the parts of the system being simulated in different cores or threads often interact and exchange information, constraining the threads to be synchronized. Simulating wireless networks with mobility, when a user equipment (UE) ceases to be served by one Base Station (BS), to be served by a new one, a synchronization point may be required, if the new BS is being simulated in another thread. In a large-scale distributed wireless network with high mobility, the simulation speed-up obtained from multi-threading could be lost to the overhead burden for synchronizing the threads. We propose a heuristic approach to assign BSs to threads in such a way as to minimize the number of synchronization points. In a time interval of the simulation, accumulated interactions are interpreted as growing graphs. Advancing through the simulation time until the number of disconnected graphs is equal to the number of desired threads, showed to be a good strategy to determine the longest intervals that can be simulated without synchronization points while taking advantage of multi-threading. By means of simulation tests we show decrements of up to 100.0 %, in the number of synchronization points, in comparison to those required for the same simulation times when assigning BSs to threads in a random and balanced way.

OSA Continuum, 2018

In this paper, a universal LP01 to any LPlm mode converter structure is proposed based on a circu... more In this paper, a universal LP01 to any LPlm mode converter structure is proposed based on a circular waveguide. As examples, nine mode converters from LP01 to LP02, LP03, LP04, LP05, LP06, LP07, LP11, LP21 and LP31 are designed. It is shown that an insertion loss of less than 3 dB is achieved over the entire C-band for all the mode converters. Furthermore, two mode (de)multiplexers based on directional couplers are demonstrated, showing an insertion loss less than 2.5 dB and a crosstalk less than −10 dB over the C-band.

Optics Communications, 2018

A novel optical waveguide LP 01 /LP 02 mode converter is proposed using combination of bicone str... more A novel optical waveguide LP 01 /LP 02 mode converter is proposed using combination of bicone structure based on the coupled-mode theory. It is composed of a cladding, a tapered core and combined bicone structure. It is found that this mode converter can have operating bandwidth of 1350-1700 nm, i.e. 350 nm, with a conversion efficiency of ∼90% (∼0.5 dB) and low crosstalk from other modes

Electronics Letters, 2018

A novel optimisation method for designing new and highly complex mode converters is presented. Ow... more A novel optimisation method for designing new and highly complex mode converters is presented. Owing to the complex relationship between the structural parameters and the output performance merit factor, it is very difficult to obtain a general algorithm. As a case study, a mode converter with eight structural parameters is designed with the proposed method. Owing to a large number of structural parameters and complexity of the designing process, the problem is formulated and optimised by using a recent optimisation algorithm called Grey Wolf Optimiser. Six optimal mode converter designs are obtained for LP 01 -LP 0m (m = 2, 3,…, 7). These optimal designs outperform existing state-of-the-art designs. Furthermore, achieving these results is done without any human involvement.

2008 International Symposium on Information Technology, 2008

... Marwan D. Saleh1, H. Mellah1, Ahmed Mueen2. ... The tested images have been acquired from the... more ... Marwan D. Saleh1, H. Mellah1, Ahmed Mueen2. ... The tested images have been acquired from the front as well as from the rear of vehicles under various illumination and weather conditions (sunny, cloudy, daytime, nigh time, rainy days...etc). ...

Journal of Computer Science, 2006

Communication Systems and Networks, 2006

CONTENTION RESOLUTION IN WDM OPTICAL PACKET SWITCHING NETWORKS USING WAVELENGTH CONVERTERS AND CA... more CONTENTION RESOLUTION IN WDM OPTICAL PACKET SWITCHING NETWORKS USING WAVELENGTH CONVERTERS AND CASCADED AUXILIARY SWITCH H. Mellah1 , FM Abbou2 1 Faculty of Information Science and Technology (FIST), 2 Alcatel Network Systems ...