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Fulltext Low complexity smart grid security protocol based on elliptic curve cryptography, biometrics and hamming distance

Mutlaq KA, Nyangaresi VO, Omar MA, Abduljabbar ZA, Abduljaleel IQ, Ma J, et al.

PLoS One, 2024;19(1):e0296781.
PMID: 38261555 DOI: 10.1371/journal.pone.0296781

The incorporation of information and communication technologies in the power grids has greatly enhanced efficiency in the management of demand-responses. In addition, smart grids have seen considerable minimization in energy consumption and enhancement in power supply quality. However, the transmission of control and consumption information over open public communication channels renders the transmitted messages vulnerable to numerous security and privacy violations. Although many authentication and key agreement protocols have been developed to counter these issues, the achievement of ideal security and privacy levels at optimal performance still remains an uphill task. In this paper, we leverage on Hamming distance, elliptic curve cryptography, smart cards and biometrics to develop an authentication protocol. It is formally analyzed using the Burrows-Abadi-Needham (BAN) logic, which shows strong mutual authentication and session key negotiation. Its semantic security analysis demonstrates its robustness under all the assumptions of the Dolev-Yao (DY) and Canetti- Krawczyk (CK) threat models. From the performance perspective, it is shown to incur communication, storage and computation complexities compared with other related state of the art protocols.

Matched MeSH terms: Computer Systems
Fulltext A renewable approach to electric vehicle charging through solar energy storage

Umair M, Hidayat NM, Sukri Ahmad A, Nik Ali NH, Mawardi MIM, Abdullah E

PLoS One, 2024;19(2):e0297376.
PMID: 38422065 DOI: 10.1371/journal.pone.0297376

Developing novel EV chargers is crucial for accelerating Electric Vehicle (EV) adoption, mitigating range anxiety, and fostering technological advancements that enhance charging efficiency and grid integration. These advancements address current challenges and contribute to a more sustainable and convenient future of electric mobility. This paper explores the performance dynamics of a solar-integrated charging system. It outlines a simulation study on harnessing solar energy as the primary Direct Current (DC) EV charging source. The approach incorporates an Energy Storage System (ESS) to address solar intermittencies and mitigate photovoltaic (PV) mismatch losses. Executed through MATLAB, the system integrates key components, including solar PV panels, the ESS, a DC charger, and an EV battery. The study finds that a change in solar irradiance from 400 W/m2 to 1000 W/m2 resulted in a substantial 47% increase in the output power of the solar PV system. Simultaneously, the ESS shows a 38% boost in output power under similar conditions, with the assessments conducted at a room temperature of 25°C. The results emphasize that optimal solar panel placement with higher irradiance levels is essential to leverage integrated solar energy EV chargers. The research also illuminates the positive correlation between elevated irradiance levels and the EV battery's State of Charge (SOC). This correlation underscores the efficiency gains achievable through enhanced solar power absorption, facilitating more effective and expedited EV charging.

Matched MeSH terms: Computer Systems
Fulltext Short term energy consumption forecasting using neural basis expansion analysis for interpretable time series

Shaikh AK, Nazir A, Khan I, Shah AS

Sci Rep, 2022 Dec 29;12(1):22562.
PMID: 36581655 DOI: 10.1038/s41598-022-26499-y

Smart grids and smart homes are getting people's attention in the modern era of smart cities. The advancements of smart technologies and smart grids have created challenges related to energy efficiency and production according to the future demand of clients. Machine learning, specifically neural network-based methods, remained successful in energy consumption prediction, but still, there are gaps due to uncertainty in the data and limitations of the algorithms. Research published in the literature has used small datasets and profiles of primarily single users; therefore, models have difficulties when applied to large datasets with profiles of different customers. Thus, a smart grid environment requires a model that handles consumption data from thousands of customers. The proposed model enhances the newly introduced method of Neural Basis Expansion Analysis for interpretable Time Series (N-BEATS) with a big dataset of energy consumption of 169 customers. Further, to validate the results of the proposed model, a performance comparison has been carried out with the Long Short Term Memory (LSTM), Blocked LSTM, Gated Recurrent Units (GRU), Blocked GRU and Temporal Convolutional Network (TCN). The proposed interpretable model improves the prediction accuracy on the big dataset containing energy consumption profiles of multiple customers. Incorporating covariates into the model improved accuracy by learning past and future energy consumption patterns. Based on a large dataset, the proposed model performed better for daily, weekly, and monthly energy consumption predictions. The forecasting accuracy of the N-BEATS interpretable model for 1-day-ahead energy consumption with "day as covariates" remained better than the 1, 2, 3, and 4-week scenarios.

Matched MeSH terms: Computer Systems*
Modified recurrent equation-based cubic spline interpolation for missing data recovery in phasor measurement unit (PMU)

Thangaraj S, Goh VT, Yap TTV

F1000Res, 2022;11:246.
PMID: 38152076 DOI: 10.12688/f1000research.73182.3

BACKGROUND: Smart grid systems require high-quality Phasor Measurement Unit (PMU) data for proper operation, control, and decision-making. Missing PMU data may lead to improper actions or even blackouts. While the conventional cubic interpolation methods based on the solution of a set of linear equations to solve for the cubic spline coefficients have been applied by many researchers for interpolation of missing data, the computational complexity increases non-linearly with increasing data size.
METHODS: In this work, a modified recurrent equation-based cubic spline interpolation procedure for recovering missing PMU data is proposed. The recurrent equation-based method makes the computations of spline constants simpler. Using PMU data from the State Load Despatch Center (SLDC) in Madhya Pradesh, India, a comparison of the root mean square error (RMSE) values and time of calculation (ToC) is calculated for both methods.
RESULTS: The modified recurrent relation method could retrieve missing values 10 times faster when compared to the conventional cubic interpolation method based on the solution of a set of linear equations. The RMSE values have shown the proposed method is effective even for special cases of missing values (edges, continuous missing values).
CONCLUSIONS: The proposed method can retrieve any number of missing values at any location using observed data with a minimal number of calculations.

Matched MeSH terms: Computer Systems*
Fulltext Big Data acquired by Internet of Things-enabled industrial multichannel wireless sensors networks for active monitoring and control in the smart grid Industry 4.0

Faheem M, Fizza G, Ashraf MW, Butt RA, Ngadi MA, Gungor VC

Data Brief, 2021 Apr;35:106854.
PMID: 33659599 DOI: 10.1016/j.dib.2021.106854

Smart Grid Industry 4.0 (SGI4.0) defines a new paradigm to provide high-quality electricity at a low cost by reacting quickly and effectively to changing energy demands in the highly volatile global markets. However, in SGI4.0, the reliable and efficient gathering and transmission of the observed information from the Internet of Things (IoT)-enabled Cyber-physical systems, such as sensors located in remote places to the control center is the biggest challenge for the Industrial Multichannel Wireless Sensors Networks (IMWSNs). This is due to the harsh nature of the smart grid environment that causes high noise, signal fading, multipath effects, heat, and electromagnetic interference, which reduces the transmission quality and trigger errors in the IMWSNs. Thus, an efficient monitoring and real-time control of unexpected changes in the power generation and distribution processes is essential to guarantee the quality of service (QoS) requirements in the smart grid. In this context, this paper describes the dataset contains measurements acquired by the IMWSNs during events monitoring and control in the smart grid. This work provides an updated detail comparison of our proposed work, including channel detection, channel assignment, and packets forwarding algorithms, collectively called CARP [1] with existing G-RPL [2] and EQSHC [3] schemes in the smart grid. The experimental outcomes show that the dataset and is useful for the design, development, testing, and validation of algorithms for real-time events monitoring and control applications in the smart grid.

Matched MeSH terms: Computer Systems
An Innovation-Driven Approach to Specific Language Impairment Diagnosis

Ch'ng YH, Osman MA, Jong HY

Malays J Med Sci, 2021 Apr;28(2):161-170.
PMID: 33958970 DOI: 10.21315/mjms2021.28.2.15

Background: Specific language impairment (SLI) diagnosis is inconvenient due to manual procedures and hardware cost. Computer-aided SLI diagnosis has been proposed to counter these inconveniences. This study focuses on evaluating the feasibility of computer systems used to diagnose SLI.
Methods: The accuracy of Webgazer.js for software-based gaze tracking is tested under different lighting conditions. Predefined time delays of a prototype diagnosis task automation script are contrasted against with manual delays based on human time estimation to understand how automation influences diagnosis accuracy. SLI diagnosis binary classifier was built and tested based on randomised parameters. The obtained results were cross-compared to Singlims_ES.exe for equality.
Results: Webgazer.js achieved an average accuracy of 88.755% under global lighting conditions, 61.379% under low lighting conditions and 52.7% under face-focused lighting conditions. The diagnosis task automation script found to execute with actual time delays with a deviation percentage no more than 0.04%, while manually executing time delays based on human time estimation resulted in a deviation percentage of not more than 3.37%. One-tailed test probability value produced by both the newly built classifier and Singlims_ES were observed to be similar up to three decimal places.
Conclusion: The results obtained should serve as a foundation for further evaluation of computer tools to help speech language pathologists diagnose SLI.

Matched MeSH terms: Computer Systems
Fulltext Spotted hyena optimizer algorithm for capacitor allocation in radial distribution system with distributed generation and microgrid operation considering different load types

Naderipour A, Abdul-Malek Z, Hajivand M, Seifabad ZM, Farsi MA, Nowdeh SA, et al.

Sci Rep, 2021 Feb 01;11(1):2728.
PMID: 33526829 DOI: 10.1038/s41598-021-82440-9

In this paper, the optimal allocation of constant and switchable capacitors is presented simultaneously in two operation modes, grid-connected and islanded, for a microgrid. Different load levels are considered by employing non-dispatchable distributed generations. The objective function includes minimising the energy losses cost, the cost of peak power losses, and the cost of the capacitor. The optimization problem is solved using the spotted hyena optimizer (SHO) algorithm to determine the optimal size and location of capacitors, considering different loading levels and the two operation modes. In this study, a three-level load and various types of loads, including constant power, constant current, and constant impedance are considered. The proposed method is implemented on a 24-bus radial distribution network. To evaluate the performance of the SHO, the results are compared with GWO and the genetic algorithm (GA). The simulation results demonstrate the superior performance of the SHO in reducing the cost of losses and improving the voltage profile during injection and non-injection of reactive power by distributed generations in two operation modes. The total cost and net saving values for DGs only with the capability of active power injection is achieved 105,780 $ and 100,560.54 $, respectively and for DGs with the capability of active and reactive power injection is obtained 89,568 $ and 76,850.46 $, respectively using the SHO. The proposed method has achieved more annual net savings due to the lower cost of losses than other optimization methods.

Matched MeSH terms: Computer Systems
Fulltext A Comparative Performance Analysis of Computational Intelligence Techniques to Solve the Asymmetric Travelling Salesman Problem

Odili JB, Noraziah A, Zarina M

Comput Intell Neurosci, 2021;2021:6625438.
PMID: 33986793 DOI: 10.1155/2021/6625438

This paper presents a comparative performance analysis of some metaheuristics such as the African Buffalo Optimization algorithm (ABO), Improved Extremal Optimization (IEO), Model-Induced Max-Min Ant Colony Optimization (MIMM-ACO), Max-Min Ant System (MMAS), Cooperative Genetic Ant System (CGAS), and the heuristic, Randomized Insertion Algorithm (RAI) to solve the asymmetric Travelling Salesman Problem (ATSP). Quite unlike the symmetric Travelling Salesman Problem, there is a paucity of research studies on the asymmetric counterpart. This is quite disturbing because most real-life applications are actually asymmetric in nature. These six algorithms were chosen for their performance comparison because they have posted some of the best results in literature and they employ different search schemes in attempting solutions to the ATSP. The comparative algorithms in this study employ different techniques in their search for solutions to ATSP: the African Buffalo Optimization employs the modified Karp-Steele mechanism, Model-Induced Max-Min Ant Colony Optimization (MIMM-ACO) employs the path construction with patching technique, Cooperative Genetic Ant System uses natural selection and ordering; Randomized Insertion Algorithm uses the random insertion approach, and the Improved Extremal Optimization uses the grid search strategy. After a number of experiments on the popular but difficult 15 out of the 19 ATSP instances in TSPLIB, the results show that the African Buffalo Optimization algorithm slightly outperformed the other algorithms in obtaining the optimal results and at a much faster speed.

Matched MeSH terms: Computer Systems
Fulltext Intelligent Malaysian Sign Language Translation System Using Convolutional-Based Attention Module with Residual Network

Khan RU, Khattak H, Wong WS, AlSalman H, Mosleh MAA, Mizanur Rahman SM

Comput Intell Neurosci, 2021;2021:9023010.
PMID: 34925497 DOI: 10.1155/2021/9023010

The deaf-mutes population always feels helpless when they are not understood by others and vice versa. This is a big humanitarian problem and needs localised solution. To solve this problem, this study implements a convolutional neural network (CNN), convolutional-based attention module (CBAM) to recognise Malaysian Sign Language (MSL) from images. Two different experiments were conducted for MSL signs, using CBAM-2DResNet (2-Dimensional Residual Network) implementing "Within Blocks" and "Before Classifier" methods. Various metrics such as the accuracy, loss, precision, recall, F1-score, confusion matrix, and training time are recorded to evaluate the models' efficiency. The experimental results showed that CBAM-ResNet models achieved a good performance in MSL signs recognition tasks, with accuracy rates of over 90% through a little of variations. The CBAM-ResNet "Before Classifier" models are more efficient than "Within Blocks" CBAM-ResNet models. Thus, the best trained model of CBAM-2DResNet is chosen to develop a real-time sign recognition system for translating from sign language to text and from text to sign language in an easy way of communication between deaf-mutes and other people. All experiment results indicated that the "Before Classifier" of CBAMResNet models is more efficient in recognising MSL and it is worth for future research.

Matched MeSH terms: Computer Systems
Fulltext A Vision-Based Machine Learning Method for Barrier Access Control Using Vehicle License Plate Authentication

Islam KT, Raj RG, Shamsul Islam SM, Wijewickrema S, Hossain MS, Razmovski T, et al.

Sensors (Basel), 2020 Jun 24;20(12).
PMID: 32599883 DOI: 10.3390/s20123578

Automatic vehicle license plate recognition is an essential part of intelligent vehicle access control and monitoring systems. With the increasing number of vehicles, it is important that an effective real-time system for automated license plate recognition is developed. Computer vision techniques are typically used for this task. However, it remains a challenging problem, as both high accuracy and low processing time are required in such a system. Here, we propose a method for license plate recognition that seeks to find a balance between these two requirements. The proposed method consists of two stages: detection and recognition. In the detection stage, the image is processed so that a region of interest is identified. In the recognition stage, features are extracted from the region of interest using the histogram of oriented gradients method. These features are then used to train an artificial neural network to identify characters in the license plate. Experimental results show that the proposed method achieves a high level of accuracy as well as low processing time when compared to existing methods, indicating that it is suitable for real-time applications.

Matched MeSH terms: Computer Systems
Fulltext PRESIMS: Requirements and design for Preschool Management System using usability theory

Nor Hasnul Azirah Abdul Hamid, Normalina Ibrahim@Mat, Nurul Najihah Mustopa

ESTEEM Academic Journal, 2020;16(2):51-64.
MyJurnal

Student Information Management System (SIMS) is a computerized system for education that can be used to manage student information and data. PASTI An-Nur is chosen as a case study in developing the system. Thus, several problems are identified that PASTI An-Nur faces due to the
implementation of a manual system in the admission process. The first problem is the paper-based registration form that is prone to lose, misplaced and less secure. As for the payment process, arise a problem in term of higher error rate when checking and calculating the payments. The biggest downfall for PASTI An-Nur is the amount of space used to store all the students' files.
These problems bring inefficiency since the world is changing to computerized, where data management become one of the most significant issues nowadays. So, the aim of developing the Preschool Management System (PRESIMS) is for helping the staffs and teachers in managing the
students' information. The Adapter Waterfall model was used in developing this system. Additionally, usability heuristics was used also as a theory to guide the development of this system. The system has been tested with the four (4) users and two (2) experts. The testing method is the ISO/IEC 9126- 4 approach to measure usability metrics, including efficiency, effectiveness, and satisfaction. Whereas, for the experts, heuristic evaluation is used to bring six (6) usability principles into implementation for testing. The result of the testing is very satisfying, which shows 75.5% of efficiency, 83.33% of effectiveness and three (3) out of four (4) users very satisfied with the system. The result of heuristic evaluation also shows a successful implementation of the system. The details of the result are discussed in this paper and expected to meet the users' specification and it is ready to go live.

Matched MeSH terms: Computer Systems
Hierarchical control strategy for a three-phase 4-wire microgrid under unbalanced and nonlinear load conditions

Naderipour A, Abdul-Malek Z, Ramachandaramurthy VK, Kalam A, Miveh MR

ISA Trans, 2019 Nov;94:352-369.
PMID: 31078293 DOI: 10.1016/j.isatra.2019.04.025

This paper proposes an improved hierarchical control strategy consists of a primary and a secondary layer for a three-phase 4-wire microgrid under unbalanced and nonlinear load conditions. The primary layer is comprised of a multi-loop control strategy to provide balanced output voltages, a harmonic compensator to reduce the total harmonic distortion (THD), and a droop-based scheme to achieve an accurate power sharing. At the secondary control layer, a reactive power compensator and a frequency restoration loop are designed to improve the accuracy of reactive power sharing and to restore the frequency deviation, respectively. Simulation studies and practical performance are carried out using the DIgSILENT Power Factory software and laboratory testing, to verify the effectiveness of the control strategy in both islanded and grid-connected mode. Zero reactive power sharing error and zero frequency steady-state error have given this control strategy an edge over the conventional control scheme. Furthermore, the proposed scheme presented outstanding voltage control performance, such as fast transient response and low voltage THD. The superiority of the proposed control strategy over the conventional filter-based control scheme is confirmed by the 2 line cycles decrease in the transient response. Additionally, the voltage THDs in islanded mode are reduced from above 5.1% to lower than 2.7% with the proposed control strategy under nonlinear load conditions. The current THD is also reduced from above 21% to lower than 2.4% in the connection point of the microgrid with the offered control scheme in the grid-connected mode.

Matched MeSH terms: Computer Systems
Fulltext Android mobile applications in eye care

Karthikeyan SK, Thangarajan R, Theruvedhi N, Srinivasan K

Oman J Ophthalmol, 2019 6 15;12(2):73-77.
PMID: 31198290 DOI: 10.4103/ojo.OJO_226_2018

Google Play Store was used to search for eye care-related applications the android simulator using various general terms related to eye care to review and categorize various interactive eye care-related applications in android platform from the details available in the application website. Data collected from application description and application developer's webpage include target audience, category of apps, estimated number of downloads, average user rating, involvement of eye care professionals in developing the application, and cost of the app. All these data were collected only from the details provided in the application website considering on online user perspective and the developers were not contacted to collect any other details. In total, 475 applications were identified and grouped into 13 categories depending on the type of service the application provide. Out of which, only 107 (22.53%) applications had mentioned about the eye care professional involvement in their design or development of the application. The applications were also stratified according to the target audience, and many had no user rating with very few downloads. The lack of evidence-based principles and standardization of application development should be taken into consideration to avoid its negative impact on the community, especially in eye care.

Matched MeSH terms: Computer Systems
Based Medical Systems for Patient's Authentication: Towards a New Verification Secure Framework Using CIA Standard

Mohsin AH, Zaidan AA, Zaidan BB, Albahri OS, Albahri AS, Alsalem MA, et al.

J Med Syst, 2019 May 22;43(7):192.
PMID: 31115768 DOI: 10.1007/s10916-019-1264-y

In medical systems for patient's authentication, keeping biometric data secure is a general problem. Many studies have presented various ways of protecting biometric data especially finger vein biometric data. Thus, It is needs to find better ways of securing this data by applying the three principles of information security aforementioned, and creating a robust verification system with high levels of reliability, privacy and security. Moreover, it is very difficult to replace biometric information and any leakage of biometrics information leads to earnest risks for example replay attacks using the robbed biometric data. In this paper presented criticism and analysis to all attempts as revealed in the literature review and discussion the proposes a novel verification secure framework based confidentiality, integrity and availability (CIA) standard in triplex blockchain-particle swarm optimization (PSO)-advanced encryption standard (AES) techniques for medical systems patient's authentication. Three stages are performed on discussion. Firstly, proposes a new hybrid model pattern in order to increase the randomization based on radio frequency identification (RFID) and finger vein biometrics. To achieve this, proposed a new merge algorithm to combine the RFID features and finger vein features in one hybrid and random pattern. Secondly, how the propose verification secure framework are followed the CIA standard for telemedicine authentication by combination of AES encryption technique, blockchain and PSO in steganography technique based on proposed pattern model. Finally, discussed the validation and evaluation of the proposed verification secure framework.

Matched MeSH terms: Computer Systems*
Fulltext Association Between Residual Inhibition and Neural Activity in Patients with Tinnitus: Protocol for a Controlled Within- and Between-Subject Comparison Study

Hu S, Anschuetz L, Huth ME, Sznitman R, Blaser D, Kompis M, et al.

JMIR Res Protoc, 2019 Jan 09;8(1):e12270.
PMID: 30626571 DOI: 10.2196/12270

BACKGROUND: Electroencephalography (EEG) studies indicate possible associations between tinnitus and changes in the neural activity. However, inconsistent results require further investigation to better understand such heterogeneity and inform the interpretation of previous findings.
OBJECTIVE: This study aims to investigate the feasibility of EEG measurements as an objective indicator for the identification of tinnitus-associated neural activities.
METHODS: To reduce heterogeneity, participants served as their own control using residual inhibition (RI) to modulate the tinnitus perception in a within-subject EEG study design with a tinnitus group. In addition, comparison with a nontinnitus control group allowed for a between-subjects comparison. We will apply RI stimulation to generate tinnitus and nontinnitus conditions in the same subject. Furthermore, high-frequency audiometry (up to 13 kHz) and tinnitometry will be performed.
RESULTS: This work was funded by the Infrastructure Grant of the University of Bern, Bern, Switzerland and Bernafon AG, Bern, Switzerland. Enrollment for the study described in this protocol commenced in February 2018. Data analysis is currently under way and the first results are expected to be submitted for publication in 2019.
CONCLUSIONS: This study design helps in comparing the neural activity between conditions in the same individual, thereby addressing a notable limitation of previous EEG tinnitus studies. In addition, the high-frequency assessment will help to analyze and classify tinnitus symptoms beyond the conventional clinical standard.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/12270.

Matched MeSH terms: Computer Systems
Fulltext Real time telecardiology system

Ming Fung Ng, Hoe Tung Yew, Seng Kheau Chung, Syed Shajee Husain, Nelbon Giloi

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):84-84.
MyJurnal

Introduction: Cardiovascular diseases remain as the principal cause of death in Malaysia. The rural areas in Sabah still suffer from shortage of doctors and specialists. Health Indicators 2018 from Ministry of Health Malaysia shows the ratio of doctor to population in Sabah is 1:1029. The lack of specialist care for the rural population is a major concern. To overcome the barrier of healthcare services, deployment of telecardiology system is necessary. The objective of this project is to develop a real-time telecardiology system that can transmit and guarantee the quality of the ECG signal. Methods: The proposed real-time telecardiology system used an ECG sensor AD8232 to collect the ECG signal. Arduino ESP32 as a main controller of the system. It uploads the collected ECG data to the online database in real-time through Wi-Fi or cellular network with MQTT protocol. A website is developed for displaying the real-time ECG signal. Results: The proposed system has successfully displayed the ECG signal in real-time with 10000 ECG raw data were tested and stored in online database with no package loss and package error during the data transmission. The online system able to display real-time ECG signal and BPM on webpage. The real-time BPM is extracted from the real-time ECG raw data. Conclusion: The proposed real-time telecardiology system has success-fully transmitted ECG in real-time with high data integrity. Telecardiology is one of the best solutions to resolve the issue of shortage of healthcare professionals in rural areas and improve the healthcare quality in rural areas.

Matched MeSH terms: Computer Systems
Fulltext Lightning performance analysis of a rooftop grid-connected solar photovoltaic without external lightning protection system

Nasir MSM, Ab-Kadir MZA, Radzi MAM, Izadi M, Ahmad NI, Zaini NH

PLoS One, 2019;14(7):e0219326.
PMID: 31295278 DOI: 10.1371/journal.pone.0219326

The Sustainable Energy Development Authority of Malaysia (SEDA) regularly receives complaints about damaged components and distribution boards of PV systems due to lightning strikes. Permanent and momentary interruptions of distribution circuits may also occur from the disturbance. In this paper, a solar PV Rooftop system (3.91 kWp) provided by SEDA was modelled in the PSCAD/EMTDC. The Heidler function was used as a lightning current waveform model to analyse the transient current and voltage at two different points susceptible to the influence of lightning events such as different lightning current wave shape, standard lightning current and non-standard lightning current. This study examines the effect on the system components when lightning directly strikes at two different points of the installation. The two points lie between the inverter and the solar PV array and between inverter and grid. Exceptionally high current and voltage due to the direct lightning strike on a certain point of a PV Rooftop system was also studied. The result of this case study is observed with and without the inclusion of surge protective devices (SPDs). The parameters used were 31 kA of peak current, 10 metres cable length and lightning impulse current wave shape of 8/20μs. The high current and voltage at P1 striking point were 31 kA and 2397 kV, respectively. As for the AC part, the current and voltage values were found to be 5.97 kA and 5392 kV, respectively.Therefore, SPDs with suitable rating provided by SEDA were deployed. Results showed that high transient current voltage is expected to clamp sharply at the values of 1.915 kV and 0 A at the P1 striking point. As for the AC part, the current and voltage values were found to be 0 kA and 0.751 V, respectively. Varying lightning impulse current wave shapes at striking point P2 showed that the highest voltage was obtained at waveshape 10/350 μs at 11277 kV followed by wave shapes of 2/70 μs, 8/20 μs and 0.7/6 μs. The high value of transient voltage was clamped at a lower level of 2.029 kV. Different lightning amplitudes were also applied, ranging from 2-200 kA selected based on the CIGRE distribution. It showed that the current and voltage at P1 and P2 were directly proportional. Therefore, the SPD will be designed at an acceptable rating and proper position of SPD installation at solar PV Rooftop will be proposed. The results obtained in this study can then be utilised to appropriately assign a SPD to protect the PV systems that are connected to the grid. Installing SPDs without considering the needs of lightning protection zones would expose the expensive equipment to potential damage even though the proper energy coordination of SPDs is in place. As such, the simulation results provide a basis for controlling the impacts of direct lightning strikes on electrical equipment and power grids and thus justify SPD coordination to ensure the reliability of the system.

Matched MeSH terms: Computer Systems
Fulltext TECHNO-ECONOMIC FEASIBILITY STUDY OF AN OFF-GRID HYBRID POWER SYSTEM FOR AN AQUA-TOURISM RESORT IN TERENGGANU, MALAYSIA

MUHAMMAD FAKHRURAZI MD YUNOS, NUR FARIZAN MUNAJAT, WAN MARIAM WAN MUDA

UMT Journal of Undergraduate Research, 2019;1(2):103-110.
MyJurnal

This study focused on feasibility analysis of hybrid electrification system for an aqua-tourism resort located remotely from the grid connection in Terengganu. There were four standalone systems used in this study: diesel/PV/biomass/battery, diesel/PV/battery, biomass/diesel/battery, and diesel only. The design and analysis of these systems were done using Hybrid Optimization of MultipleEnergy Resources (HOMER) software. The results showed that the diesel/PV/battery system was the optimum solution in terms of net present cost (NPC) and cost of energy (COE). This system comprises 20 % of PV penetration with NPC and COE of USD 57,823 (RM 241, 729.90) and 0.428 USD/kWh (1.79 RM/kWh), respectively. Meanwhile, the diesel/PV/biomass/battery system with NPC of USD 65,388 (RM 273, 355.49) and COE of 0.484 USD/kWh (2.02 RM/kWh) was found to be the best among all systems in terms of greenhouse emissions. This system was able to reduce almost 70 % of carbon dioxide if compared with diesel only system and about 15 % lower than the diesel/PV/battery system with a renewable energy fraction of 44 %.

Matched MeSH terms: Computer Systems
Fulltext ESTIMATION OF SAND DISTRIBUTION IN CORAL REEF ENVIRONMENT USING COLOURSEGMENTATION AND COLOURTHRESHOLDING METHODS

PAULEEN ONG, MUHAMMAD SUZURI HITAM, ZAINUDDIN BACHOK, ZAINUDDIN BACHOK, MOHD SAFUAN CHE DIN

UMT Journal of Undergraduate Research, 2019;1(3):96-104.
MyJurnal

At present, marine scientists employ manual method to estimate the components in coral reef environment,where Coral Point Count with Excel extensions (CPCe) software is used to determine the coral reef components and substrate coverage. This manual processis laboriousand time consuming,and needsexpertsto conduct the survey. In this paper, a prototype for estimating the distribution of sand cover in coral reef environment from still images by using colourextraction methods was introduced. The coloursegmentation called delta E was used to calculate the colourdifference between two coloursamples. Another method used wascolourthresholdby setting the range of sand colourpixels. Thesystem was developed by using a MATLAB software withimage processing toolbox. The developed system was semi-automatic computer-based system that can be used by researcherseven with little knowledge and experience to estimatethepercentage of sand coveragein coral reef still images.

Matched MeSH terms: Computer Systems
Fulltext DAD-match; Security technique to prevent denial of service attack on duplicate address detection process in IPv6 link-local network

Al-Ani AK, Anbar M, Manickam S, Al-Ani A

PLoS One, 2019;14(4):e0214518.
PMID: 30939154 DOI: 10.1371/journal.pone.0214518

An efficiently unlimited address space is provided by Internet Protocol version 6 (IPv6). It aims to accommodate thousands of hundreds of unique devices on a similar link. This can be achieved through the Duplicate Address Detection (DAD) process. It is considered one of the core IPv6 network's functions. It is implemented to make sure that IP addresses do not conflict with each other on the same link. However, IPv6 design's functions are exposed to security threats like the DAD process, which is vulnerable to Denial of Service (DoS) attack. Such a threat prevents the host from configuring its IP address by responding to each Neighbor Solicitation (NS) through fake Neighbor Advertisement (NA). Various mechanisms have been proposed to secure the IPv6 DAD procedure. The proposed mechanisms, however, suffer from complexity, high processing time, and the consumption of more resources. The experiments-based findings revealed that all the existing mechanisms had failed to secure the IPv6 DAD process. Therefore, DAD-match security technique is proposed in this study to efficiently secure the DAD process consuming less processing time. DAD-match is built based on SHA-3 to hide the exchange tentative IP among hosts throughout the process of DAD in an IPv6 link-local network. The obtained experimental results demonstrated that the DAD-match security technique achieved less processing time compared with the existing mechanisms as it can resist a range of different threats like collision and brute-force attacks. The findings concluded that the DAD-match technique effectively prevents the DoS attack during the DAD process. The DAD-match technique is implemented on a small area IPv6 network; hence, the author future work is to implement and test the DAD-match technique on a large area IPv6 network.

Matched MeSH terms: Computer Systems

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