Chemical composition of essential oil of exudates of Dryobalanops aromatica

Purpose: To identify the chemical composition of essential oil from the exudates of Dryobalanops aromatica from Malaysia.Methods: Exudate was collected from D. aromatica and subjected to fractional  distillation to obtain essential oil. Gas chromatography-mass spectrometry  (GC-MS) was used to characterize the composition of the isolated essential oil.Results: The yield of essential oil was 7.58 %, with the highest yield (3.24 %) within the first 2 h of fractional distillation. Thirty compounds which accounted for 97.56 % of essential oil composition were identified. These include sesquiterpenes (46.87 %), monoterpenes (31.05 %), oxygenated monoterpenes (16.76 %) and oxygenated  sesquiterpenes (2.13 %). Borneol accounted for 0.74 % of the essential oil.Conclusion: Essential oil from the exudates of D. aromatica contains terpenoid  compounds and borneol.Keywords: Dryobalanops aromatica, exudate, fractional distillation, essential oil, GS-MS, borneo

Determination of borneol and other chemical compounds of essential oil of Dryobalanops aromatica exudate from Malaysia

Purpose: To determine borneol and other chemical compounds of essential oil derived from the exudate of Dryobalanops aromatica in Malaysia.Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was performed to characterize the composition of the isolated essential oil.Results: Essential oil (7.58 %) was obtained with the highest yield (3.24 %) in the first 2 h of fractional distillation. Thirty compounds which accounted for 97.56 % of total essential oil composition were identified by GC-MS, and they include sesquiterpenes (46.87 %), monoterpenes (31.05 %), oxygenated monoterpenes (16.76 %) and oxygenated sesquiterpenes (2.13 %). Borneol (0.74 %) was also detected in the essential oil.Conclusion: Borneol and other terpenoid compounds are present in the essential oil of the exudate of D. aromatica.Keywords: Exudate, Dryobalanops Aromatica, Fractional distillation, Essential oil, Gaschromatography-mass spectrometry, Borneo

Joint Security-vs-QoS Framework:Optimizing the Selection of Intrusion Detection Mechanisms in 5G networks

The advent of 5G technology introduces new - and potentially undiscovered - cybersecurity challenges, with unforeseen impacts on our economy, society, and environment. Interestingly, Intrusion Detection Mechanisms (IDMs) can provide the necessary network monitoring to ensure - to a big extent - the detection of 5G-related cyberattacks. Yet, how to realize the attack surface of 5G networks with respect to the detected risks, and, consequently, how to optimize the cybersecurity levels of the network, remains an open critical challenge. In respect, this work focuses on deploying multiple distributed Security Agents (SAs) that can run different IDMs over various network components and proposes a cybersecurity mechanism for optimizing the network’s attack surface with respect to the Quality of Service (QoS). The proposed approach relies on a new closed-form utility function to describe the trade-off between cybersecurity and QoS and uses multi-objective optimization to improve the selection of each SA detection level. We demonstrate via simulations that before optimization, an increase in the detection level of SAs brings a direct decrease in QoS as more computational, bandwidth and monetary resources are utilized for IDM processing. Thereby, after optimization, we demonstrate that our mechanism can strike a balance between cybersecurity and QoS while showcasing the impact of the importance of different objectives of the joint optimization

Multiuser Detector For CDMA Communication System Using Evolutionary Programming

In this thesis , an investigation is made on the application of evolutionary programming (EP) in the problem of multiuser detection in code-division multiple access (CDMA) communication systems. EP is a powerful and general global optimization algorithm

Robust Techniques For DS-CDMA Systems In Impulsive Noise Channels

In this thesis, we propose new robust techniques for multiuser detection and channel estimation in the presence of noise modeled as symmetric alpha-stable processes

Secrecy improvement via joint optimization of UAV relay flight path and transmit power

Eavesdropping occurs when an unauthorized receiver secretly intercepts a transmitted signal. In this paper, we investigate the optimum flight path and transmit power for an unmanned aerial vehicle (UAV) relay to improve secrecy performance in the presence of an eavesdropper. We propose an algorithm based on particle swarm optimization (PSO) where the UAV flight path and power are jointly optimized to maximize the secrecy capacity. Simulation results show that the proposed algorithm is capable of achieving a performance that is close to the ideal secrecy performance. Simulation results also highlight the benefits of power optimization

An efficient local search heuristics for asynchronous multiuser detection

This letter considers the application of k-opt local search to the detection of data transmitted through the additive white Gaussian noise channel by K asynchronous users using direct-sequence code-division multiple access. The algorithm is based on a general approach to heuristics that is highly efficient in solving large combinatorial optimization problems. It is shown that the algorithm manage to produce optimum solutions with high frequency, in running time that grows about O(n(2))