Displaying publications 41 - 60 of 794 in total

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  1. Islam MR, Ali MM, Lai MH, Lim KS, Ahmad H
    Sensors (Basel), 2014;14(4):7451-88.
    PMID: 24763250 DOI: 10.3390/s140407451
    Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.
    Matched MeSH terms: Fiber Optic Technology
  2. Yang HZ, Lim KS, Qiao XG, Chong WY, Cheong YK, Lim WH, et al.
    Opt Express, 2013 Jun 17;21(12):14808-15.
    PMID: 23787668 DOI: 10.1364/OE.21.014808
    We present a new theoretical model for the broadband reflection spectra of etched FBGs which includes the effects of axial contraction and stress-induced index change. The reflection spectra of the etched FBGs with several different taper profiles are simulated based on the proposed model. In our observation, decaying exponential profile produces a broadband reflection spectrum with good uniformity over the range of 1540-1560 nm. An etched FBG with similar taper profile is fabricated and the experimental result shows good agreement with the theoretical model.
    Matched MeSH terms: Fiber Optic Technology/instrumentation*
  3. Rahman HA, Che Ani AI, Harun SW, Yasin M, Apsari R, Ahmad H
    J Biomed Opt, 2012 Jul;17(7):071308.
    PMID: 22894469 DOI: 10.1117/1.JBO.17.7.071308
    The purpose of this study is to investigate the potential of intensity modulated fiber optic displacement sensor scanning system for the imaging of dental cavity. Here, we discuss our preliminary results in the imaging of cavities on various teeth surfaces, as well as measurement of the diameter of the cavities which are represented by drilled holes on the teeth surfaces. Based on the analysis of displacement measurement, the sensitivities and linear range for the molar, canine, hybrid composite resin, and acrylic surfaces are obtained at 0.09667 mV/mm and 0.45 mm; 0.775 mV/mm and 0.4 mm; 0.5109 mV/mm and 0.5 mm; and 0.25 mV/mm and 0.5 mm, respectively, with a good linearity of more than 99%. The results also show a clear distinction between the cavity and surrounding tooth region. The stability, simplicity of design, and low cost of fabrication make it suitable for restorative dentistry.
    Matched MeSH terms: Fiber Optic Technology/instrumentation*
  4. Lim KS, Jasim AA, Damanhuri SS, Harun SW, Rahman BM, Ahmad H
    Appl Opt, 2011 Oct 20;50(30):5912-6.
    PMID: 22015420 DOI: 10.1364/AO.50.005912
    Effects of immersing a microfiber knot resonator (MKR) in liquid solutions that have refractive indices close to that of silica are experimentally demonstrated and theoretically analyzed. Significant improvement in resonance extinction ratio within 2 to 10 dB was observed. To achieve a better understanding, a qualitative analysis of the coupling ratio and round-trip attenuation of the MKR is performed by using a curve-fitting method. It was observed that the coupling coefficient at the knot region increased when immersed in liquids. However, depending on the initial state of the coupling and the quantity of the increment in the coupling coefficient when immersed in a liquid, it is possible that the MKR may experience a deficit in the coupling parameter due to the sinusoidal relationship with the coupling coefficient.
    Matched MeSH terms: Fiber Optic Technology
  5. Shirazi MR, Harun SW, Biglary M, Ahmad H
    Opt Lett, 2008 Apr 15;33(8):770-2.
    PMID: 18414527
    A configuration for linear cavity Brillouin fiber laser (BFL) generation is demonstrated using a standard single-mode fiber, two optical circulators, a 3 dB coupler, and a 95/5 coupler to allow high efficiency. With a Brillouin pump (BP) power of 13 dBm, the laser peak power is 12.3 dB higher than a conventional linear cavity BFL at an upshifted wavelength of 0.086 nm from the BP wavelength. In addition, it is revealed that the BFL peak power can be higher than the transmitted BP peak power when the BP power exceeds the second Brillouin Stokes threshold power.
    Matched MeSH terms: Fiber Optic Technology
  6. Mohammad, Thamer Ahmad, Mohd. Razali Abdul Kadir, Megat Johari Megat Mohd. Noor, Ahmad Husaini Sulaiman
    MyJurnal
    Part of the Seremban flood mitigation project in the state of Negeri Sembilan, Malaysia is to mitigate
    the flood at Jalan Rasah. The mitigation is planned to be implemented in packages. Package I and Package II of River Anak Air Rasah are parts of the project work. In these packages, wider and deeper concrete sections for the river are constructed. The existing undersized culverts were replaced by bigger reinforced concrete box culverts. The size of the box culverts was based on 100-years average reoccurrence interval (ARI). One of these culverts intersected with a rail line connecting Singapore and Malaysia. Trenchless jacking technique was used to lay the box culvert. The total length of the box culvert jacked under the railway line is 33 m, whereas the total width of the twin box culvert is 7.8 m with a total height of 3 m. This was the first time that the trenchless jacking techniques were used for the urban flood mitigation purpose in Malaysia, and it is mainly used to minimise traffic disruption. This study reports the success of using jacking technique in the development of the flood mitigation program of DID in Negeri Sembilan. Among other things, it explains significant performance of the technique under local conditions and experiences gained towards the advancement of tunnelling and trenchless technology.
    Matched MeSH terms: Technology
  7. Aldhaibani JA, Yahya A, Ahmad RB
    ScientificWorldJournal, 2014;2014:815720.
    PMID: 24672378 DOI: 10.1155/2014/815720
    The poor capacity at cell boundaries is not enough to meet the growing demand and stringent design which required high capacity and throughput irrespective of user's location in the cellular network. In this paper, we propose new schemes for an optimum fixed relay node (RN) placement in LTE-A cellular network to enhance throughput and coverage extension at cell edge region. The proposed approach mitigates interferences between all nodes and ensures optimum utilization with the optimization of transmitted power. Moreover, we proposed a new algorithm to balance the transmitted power of moving relay node (MR) over cell size and providing required SNR and throughput at the users inside vehicle along with reducing the transmitted power consumption by MR. The numerical analysis along with the simulation results indicates that an improvement in capacity for users is 40% increment at downlink transmission from cell capacity. Furthermore, the results revealed that there is saving nearly 75% from transmitted power in MR after using proposed balancing algorithm. ATDI simulator was used to verify the numerical results, which deals with real digital cartographic and standard formats for terrain.
    Matched MeSH terms: Wireless Technology*
  8. Aziz Bin Deraman, Ahmad Shukri Bin Yahaya
    A study was conducted to examine the usage of application software and its development practices in Malaysia. The study has shown that the use of application software is greatly emphasized by organizations in their respective businesses. And for most organizations, the application software is supplied by a vendor or through in house development. For the software development practices, the deployment of a current technique and technology is still inadequate. Therefore, most of the existing information technology practitioners should be given additional training on the latest techniques of software development. Other aspect of improvement on software development practices is also discussed.
    Satu kajian terhadap status pemakaian dan kegiatan pembangunan perisian gunaan di Malaysia telah dijalankan. Kajian ini menunjukkan yang aspek pemakaian sangat diberi penekanan oleh organisasi. Manakala proses perolehan perisian gunaan pula terbahagi secara setara di antara buat sendiri dengan menggunakan pihak ketiga. Namun begitu yang ketara ialah kadar penggunaan teknologi dan teknik terkini dalam kegiatan pembangunan perisian masih berkurangan. Oleh itu disarankan supaya aspek latihan teknik kakitangan teknologi maklumat organisasi perlu dipertingkatkan secara berterusan. Di samping itu kajian ini memaparkan beberapa aspek amalan pembangunan perisian yang boleh diperbaiki lagi.
    Matched MeSH terms: Technology
  9. Yaacob I, Harun Z, Ahmad Z
    Singapore Med J, 1991 Feb;32(1):26-8.
    PMID: 2017700
    Two hundred and ninety-three bronchoscopies were done for 285 patients (78% males, 22% females) at Hospital University Sains Malaysia between 1984 and 1988. The mean age was 56.4 years (range 13 to 90 years). 70.2% of patients underwent bronchoscopies to confirm or exclude the diagnosis of carcinoma of the bronchus, out of which 58% were confirmed to have bronchial carcinoma. 77% of the 98 patients with visible endobronchial tumours had biopsy specimens diagnostic of malignancy. Brushing and washing cytology increased the positive yield to 92%. The commonest histological type of bronchial carcinoma identified was squamous cell carcinoma (48.1%), followed by small cell carcinoma (27.1%), anaplastic/undifferentiated carcinoma (12.9%), adenocarcinoma (9.4%) and large cell carcinoma (2.4%). Bronchoscopy for the investigation of haemoptysis identified the commonest cause as 'bronchitis'. There were no complications noted in our series. Notable differences of our experience compared to that of the western series were the high percentage of bronchoscopy done for infective respiratory disorders and the younger age of our patients.
    Matched MeSH terms: Fiber Optic Technology
  10. Norlela Yacob, Faizah Abdul Fatah, Wan Nor Syariza Wan Ali, Nusima Mohamed, Winarti, Tine Martina, Aida Ali
    MyJurnal
    Copy denture technique is a classic technique for construction of a new denture
    based on the favourable aspects of the original denture using a replica. This technique helps in
    adaptation of new denture in elderly population. The aim of this paper was to assess the knowledge
    and practice of copy denture technique among dentists and dental technologists. (Copied from article).
    Matched MeSH terms: Technology, Dental
  11. Noraishah, O., Mohd Arif, H., Fadil Ismail, Nurliyana Abdullah, Mior Ahmad Khusaini, Mohamad Rabaie, S., et al.
    MyJurnal
    The radiotracer injector is meant for transferring liquid radiotracer in the system for industrial radiotracer application with minimal radiation exposure to the operator. The motivation of its invention is coming from the experience of the workers who are very concern about the radiation safety while handling with the radioactive source. The idea ensuring the operation while handling the radioactive source is fast and safe without interrupting the efficiency and efficacy of the process. Thus, semi automated device assisting with pneumatic technology is applied for its invention.
    Matched MeSH terms: Technology
  12. Shamim A, Khan AA, Qureshi MA, Rafique H, Akhunzada A
    PMID: 34639652 DOI: 10.3390/ijerph181910352
    Traditional taxi services have now been transformed into e-hailing applications (EHA) such as Uber, Careem, Hailo, and Grab Car globally due to the proliferation of smartphone technology. On the one hand, these applications provide transport facilities. On the other hand, users are facing multiple issues in the adoption of EHAs. Despite problems, EHAs are still widely adopted globally. However, a sparse amount of research has been conducted related to EHAs, particular in regards to exploring the significant factors of intention behind using EHAs Therefore, there is a need to identify influencing factors that have a great impact on the adoption and acceptance of these applications. Hence, this research aims to present an empirical study on the factors influencing customers' intentions towards EHAs. The Technology Acceptance Model (TAM) was extended with four external factors: perceived mobility value, effort expectancy, perceived locational accuracy, and perceived price. A questionnaire was developed for the measurement of these factors. A survey was conducted with 211 users of EHAs to collect data. Structural equation modeling (SEM) was used to analyze the collected data. The results of this study exposed that perceived usefulness, perceived price, and perceived ease of use affect behavior intention to use EHAs. Furthermore, perceived ease of use was impacted by effort expectancy, perceived locational accuracy, and perceived mobility. The findings of the study provide a foundation to develop new guidelines for such applications that will be beneficial for developers and designers of these applications.
    Matched MeSH terms: Technology
  13. Qazi HH, bin Mohammad AB, Akram M
    Sensors (Basel), 2012 Nov 29;12(12):16522-56.
    PMID: 23443392 DOI: 10.3390/s121216522
    Optical chemical sensors have promoted escalating interest in the determination of various pollutants in the environment, which are creating toxicity and may cause serious health problems. This review paper focuses particularly on the recent progress and developments in this field; the working principles and basic classes of optical chemical sensors have been briefly described.
    Matched MeSH terms: Fiber Optic Technology
  14. Brza MA, Aziz SB, Anuar H, Al Hazza MHF
    Int J Mol Sci, 2019 Aug 11;20(16).
    PMID: 31405255 DOI: 10.3390/ijms20163910
    The present work proposed a novel approach for transferring high-risk heavy metals tometal complexes via green chemistry remediation. The method of remediation of heavy metals developed in the present work is a great challenge for global environmental sciences and engineering because it is a totally environmentally friendly procedure in which black tea extract solution is used. The FTIR study indicates that black tea contains enough functional groups (OH and NH), polyphenols and conjugated double bonds. The synthesis of copper complex was confirmed by the UV-vis, XRD and FTIR spectroscopic studies. The XRD and FTIR analysis reveals the formation of complexation between Cu metal complexes and Poly (Vinyl Alcohol) (PVA) host matrix. The study of optical parameters indicates that PVA-based hybrids exhibit a small optical band gap, which is close to inorganic-based materials. It was noted that the absorption edge shifted to lower photon energy. When Cu metal complexes were added to PVA polymer, the refractive index was significantly tuned. The band gap shifts from 6.2 eV to 1.4 eV for PVA incorporated with 45 mL of Cu metal complexes. The nature of the electronic transition in hybrid materials was examined based on the Taucs model, while a close inspection of the optical dielectric loss was also performed in order to estimate the optical band gap. The obtained band gaps of the present work reveal that polymer hybrids with sufficient film-forming capability could be useful to overcome the drawbacks associated with conjugated polymers. Based on the XRD results and band gap values, the structure-property relationships were discussed in detail.
    Matched MeSH terms: Green Chemistry Technology/methods
  15. 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: Wireless Technology*
  16. Chaudhry MH, Ahmad A, Gulzar Q, Farid MS, Shahabi H, Al-Ansari N
    Sensors (Basel), 2021 Feb 27;21(5).
    PMID: 33673425 DOI: 10.3390/s21051649
    Unmanned Aerial Vehicle (UAV) is one of the latest technologies for high spatial resolution 3D modeling of the Earth. The objectives of this study are to assess low-cost UAV data using image radiometric transformation techniques and investigate its effects on global and local accuracy of the Digital Surface Model (DSM). This research uses UAV Light Detection and Ranging (LIDAR) data from 80 meters and UAV Drone data from 300 and 500 meters flying height. RAW UAV images acquired from 500 meters flying height are radiometrically transformed in Matrix Laboratory (MATLAB). UAV images from 300 meters flying height are processed for the generation of 3D point cloud and DSM in Pix4D Mapper. UAV LIDAR data are used for the acquisition of Ground Control Points (GCP) and accuracy assessment of UAV Image data products. Accuracy of enhanced DSM with DSM generated from 300 meters flight height were analyzed for point cloud number, density and distribution. Root Mean Square Error (RMSE) value of Z is enhanced from ±2.15 meters to 0.11 meters. For local accuracy assessment of DSM, four different types of land covers are statistically compared with UAV LIDAR resulting in compatibility of enhancement technique with UAV LIDAR accuracy.
    Matched MeSH terms: Remote Sensing Technology
  17. Onwuegbuzie IU, Abd Razak S, Fauzi Isnin I, Darwish TSJ, Al-Dhaqm A
    PLoS One, 2020;15(8):e0237154.
    PMID: 32797055 DOI: 10.1371/journal.pone.0237154
    Data prioritization of heterogeneous data in wireless sensor networks gives meaning to mission-critical data that are time-sensitive as this may be a matter of life and death. However, the standard IEEE 802.15.4 does not consider the prioritization of data. Prioritization schemes proffered in the literature have not adequately addressed this issue as proposed schemes either uses a single or complex backoff algorithm to estimate backoff time-slots for prioritized data. Subsequently, the carrier sense multiple access with collision avoidance scheme exhibits an exponentially increasing range of backoff times. These approaches are not only inefficient but result in high latency and increased power consumption. In this article, the concept of class of service (CS) was adopted to prioritize heterogeneous data (real-time and non-real-time), resulting in an optimized prioritized backoff MAC scheme called Class of Service Traffic Priority-based Medium Access Control (CSTP-MAC). This scheme classifies data into high priority data (HPD) and low priority data (LPD) by computing backoff times with expressions peculiar to the data priority class. The improved scheme grants nodes the opportunity to access the shared medium in a timely and power-efficient manner. Benchmarked against contemporary schemes, CSTP-MAC attained a 99% packet delivery ratio with improved power saving capability, which translates to a longer operational lifetime.
    Matched MeSH terms: Wireless Technology*
  18. Ganasegeran K, Renganathan P, Rashid A, Al-Dubai SA
    Int J Med Inform, 2017 01;97:145-151.
    PMID: 27919374 DOI: 10.1016/j.ijmedinf.2016.10.013
    BACKGROUND: The dawn of m-Health facilitates new horizons of professional communication through WhatsApp, allowing health professionals to interact fast and efficiently for effective patient management. This preliminary study aimed to investigate perceived benefits, if any, of WhatsApp use across general medical and emergency teams during clinical practice in Malaysia.

    METHODS: A cross-sectional study was conducted in a universal sample of 307 health professionals comprising of nurses, medical assistants, medical residents, medical officers and physicians across medical and casualty departments in a Malaysian public hospital. The self-administered questionnaire consisted of items on socio-demographics, WhatsApp usage characteristics and the type of communication events during clinical practice.

    RESULTS: The majority of respondents (68.4%) perceived WhatsApp as beneficial during clinical practice. In multivariate analysis, perceived benefits was significantly higher amongst the clinical management group (aOR=2.6, 95% CI 1.5-4.6, p=0.001), those using WhatsApp for >12months (aOR=1.7, 95% CI 1.0-3.0, p=0.047), those receiving response ≤15min to a new communication (aOR=1.9, 95% CI 1.1-3.2, p=0.017), and frequent information giving events (aOR=2.4, 95% CI 1.2-4.8, p=0.016).

    CONCLUSION: Perceived benefits of WhatsApp use in clinical practice was significantly associated with usage characteristics and type of communication events. This study lays the foundation for quality improvement innovations in patient management delivered through m-Health technology.

    Matched MeSH terms: Wireless Technology*
  19. Shaddad RQ, Mohammad AB, Al-Gailani SA, Al-Hetar AM
    ScientificWorldJournal, 2014;2014:170471.
    PMID: 24772009 DOI: 10.1155/2014/170471
    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength.
    Matched MeSH terms: Fiber Optic Technology*; Wireless Technology*
  20. Abass AK, Al-Mansoori MH, Jamaludin MZ, Abdullah F, Al-Mashhadani TF
    Appl Opt, 2013 Jun 1;52(16):3764-9.
    PMID: 23736332 DOI: 10.1364/AO.52.003764
    We experimentally investigate the performance of L-band multiwavelength Brillouin-Raman fiber laser (MBRFL) under forward and backward pumped environments utilizing a linear cavity. A short length of 1.18 km dispersion compensating fiber is used as a nonlinear gain medium for both Brillouin and Raman gain. Experimental results indicate that the gain in the copumped laser configuration is higher than the gain in the counterpumped configuration. A stable and constant number of Brillouin Stokes lines up to 23 Stokes, with channel spacing of 0.08 nm and more than 20 dB of optical signal to noise ratio, can be generated as well as tuning over 20 nm in the L-band region from 1570 to 1590 nm. The laser generating the Brillouin Stokes lines exhibits flat amplitude bandwidth and high average output power of 0.8 and 1.6 dBm for the copropagation and counterpropagation pumps, respectively. Moreover, the tuning range bandwidth of the MBRFL can be predicted from the oscillated Brillouin pump gain profile.
    Matched MeSH terms: Fiber Optic Technology
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