Displaying publications 41 - 60 of 173 in total

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  1. Ngah, U.K., Aziz, S.A., Aziz, M.E., Murad, M., Mahdi, N.M.N., Shakaff, A.Y.M., et al.
    ASM Science Journal, 2008;2(1):1-11.
    MyJurnal
    The incidences of breast cancer have been rising at an alarming rate. Mass breast screening programmes involving mammography and ultrasound in certain parts of the world have also proven their benefits in early detection. However, radiologists may be confronted with increased workload. An attempt has been made in this paper to rectify part of the problems faced in this area. Expert systems based on the interpretation of mammographic and ultrasound images for classifying patient cases could be utilized by doctors (expert and non-expert) in screening. These softwares consist of MAMMEX (for mammogram) and SOUNDEX (for breast ultrasound) could be used to deduce cases according to Breast Imaging Recording and Data System (BI-RADS), based on patients’ history, physical and clinical assessment, mammograms and breast ultrasound images. A total of 179 retrospective cases from the Radiology Department, hospital of the University of Science Malaysia, Kubang Kerian, Kelantan were used in this study. A receiver operating characteristic (ROC) curve analysis was implemented, based on the usage of a two-class forced choice of classifying suspicious and malignant findings as positive with normal, benign and probably benign classified as negative. Results yielded an area under the curve (AUC) of 0.997 with the least standard error value of 0.003 for MAMMEX while an AUC of 0.996 with the least standard error of 0.004 was accomplished for SOUNDEX. A system which very closely simulated radiologists was also successfully developed in this study. The ROC curve analysis indicated that the expert systems developed were of high performance and reliability.
  2. Al-Haddad, S.A.R., Samad, S.A., Hussain, A., Ishak, K.A., Noor, A.O.A.
    ASM Science Journal, 2008;2(1):75-81.
    MyJurnal
    Robustness is a key issue in speech recognition. A speech recognition algorithm for Malay digits from zero to nine and an algorithm for noise cancellation by using recursive least squares (RLS) is proposed in this article. This system consisted of speech processing inclusive of digit margin and recognition using zero crossing and energy calculations. Mel-frequency cepstral coefficient vectors were used to provide an estimate of the vocal tract filter. Meanwhile dynamic time warping was used to detect the nearest recorded voice with appropriate global constraint. The global constraint was used to set a valid search region because the variation of the speech rate of the speaker was considered to be limited in a reasonable range which meant that it could prune the unreasonable search space. The algorithm was tested on speech samples that were recorded as part of a Malay corpus. The results showed that the algorithm managed to recognize almost 80.5% of the Malay digits for all recorded words. The addition of a RLS noise canceller in the preprocessing stage increased the accuracy to 94.1%.
  3. Chai, S.P., Zein, S.H.S., Mohamed, A.R.
    ASM Science Journal, 2008;2(1):57-64.
    MyJurnal
    Since the discovery of carbon nanotubes (CNTs) in 1991, a fundamental question still remained on how to control morphologically the synthesis of CNTs. This task has always been a challenge. In this paper, we report the results that we have published previously with the aim of sharing the possible controlled synthesis approach via this novel production method. Findings demonstrated that various CNTs could be synthesized by using specially developed supported catalysts from the catalytic decomposition of methane. These synthesized CNTs include carbon nanofibres, single-walled and multi-walled CNTs, Y-junction CNTs and CNTs with special morphologies. It was also revealed that catalyst composition and reaction parameters played an important role in controlling the morphology and type of CNTs formed. The synthesis of CNTs with various morphologies is important because this can enrich the nanostructures of the carbon family. This finding also provides useful data for better understanding of the parameters that govern the growth mechanism of CNTs which may be required in the near future for enhanced controlled synthesis of CNTs.
  4. Hashida, N.H., Abdullah, R.B.
    ASM Science Journal, 2008;2(1):65-73.
    MyJurnal
    This study was carried out to compare the ultrastructure of fresh, capacitated and acrosome-reacted sperm. The sperm was treated with heparin for capacitation and calcium ionophore for acrosome reaction induction. Sperm samples were then prepared for ultrastructural studies and examined by transmission electron microscopy (TEM). Ultrastructural changes in plasma and acrosomal membranes, shape of the mitochondria and outer dense fibres, in capacitated and acrosome-reacted sperm were evident. The plasma membrane of fresh sperm was loosely fitted around the sperm head and the acrosomal membrane was closely opposed to the nucleus. The plasma and acrosomal membranes of the capacitated sperm were expanded, but disintegrated in the acrosome-reacted sperm. Mitochondria of fresh sperm appeared to be rounded in shape with plasma membrane closely opposed to it and the nine outer dense fibres were almost regular rounded in shape. However, in both capacitated and acrosome-reacted sperm, the mitochondria were almost regular and elongated in shape whilst the outer dense fibres were irregular in shape in the capacitated and acrosome-reacted sperm. There were no noticeable morphological changes found in the axonemal complexes in fresh, capacitated and acrosome-reacted sperm. Ultrastructural studies are able to provide detailed information on sequential events involving numerous physiological changes during fertilization.
  5. Harun, S.W., Tamjis, M.R., Muhd-Yassin, S.Z., Abd-Rahman, M.K., Ahmad, H.
    ASM Science Journal, 2007;1(2):129-133.
    MyJurnal
    This paper demonstrates an erbium/ytterbium co-doped fi bre amplifi er (EYDFA) which used a pumping wavelength of 1058 nm, whereby the amplifi cation was assisted by the energy transfer between Yb and Er ions. The energy transfer increased the erbium doping concentration limit that was imposed by concentration quenching in erbium-doped fi bre. The optimum length was obtained at 4m~6m for erbium/ytterbium co-doped fi bre with Er ion concentration of 1000 p.p.m. This enabled the development of a compact amplifi er with a shorter gain medium compared to erbium-doped fi bre amplifi ers which use a gain medium of up to 15 m. A 1058 nm pumping wave-length was used for the EYDFA, as 1480 nm pumping resulted in severely degraded gain and noise fi gures because the energy transfer could not be achieved. The use of the optical isolator improved the small signal gain and noise fi gure by about 4.8 dB and 1.6 dB, respectively. Without the isolator, gain saturation and a noise fi gure penalty were observed due to the oscillating laser which was created at around 1534 nm by spurious refl ection. This showed that the usage of optical isolators was an important aspect to consider when designing an EYDFA.
  6. Ismail, A.
    ASM Science Journal, 2007;1(2):169-175.
    MyJurnal
    As we move towards the knowledge (K) era, the challenge in R&D is to focus on the development of original K-based products that can compete in the global market. The development of commercially viable, patented K-based products within a university environment require an innovation system and innovation policies in place and a change in the paradigm towards the approach to research. A crucial agent towards the success of the innovation system is development and training of the human capital that would be the future drivers of the K-industry. Awareness of intellectual property rights, the need for original research, entrepreneurship as well as the development and strengthening of self-confidence and leadership are among the factors needed towards the training of K-workers facing the new economy.
  7. Rashid, A.S., Khatun, S., Ali, B.M., Khazani, A.M.
    ASM Science Journal, 2008;2(1):13-22.
    MyJurnal
    An analysis of the power spectral density of ultra-wideband (UWB) signals is presented in order to evaluate the effects of cumulative interference from multiple UWB devices on victim narrowband systems in their overlay bands like WiFi (i.e. IEEE802.11a) and 3rdG systems (Universal mobile telecommunications system/wideband code division multiple access). In this paper, the performances are studied through the bit-error-rate as a function of signal-to-noise ratio as well as signal-to-interference power ratio using computer simulation and exploiting the realistic channel model (i.e. modified Saleh-Valenzuela model). Several modifications of a generic Gaussian pulse waveform with lengths in the order of nanoseconds were used to generate UWB spectra. Different kinds of pulse modulation (i.e. antipodal and orthogonal) schemes were also taken into account.
  8. Ariffin, A., Khan, M.N., Sim, Y.L.
    ASM Science Journal, 2008;2(1):83-92.
    MyJurnal
    The rate of aqueous cleavage of N-(2’-hydroxyphenyl)phthalimide (A), monitored at 320 nm, 1.0  10–3 M NaOH, 35ºC and within CH3CN content range 1% – 80% v/v in mixed aqueous solvents, follows the reaction scheme: A + HO-/H2O ➝ B + HO-/H2O ➝ P1 + P2 where B, P1 and P2 represent N-(2’-hydroxyphenyl)phthalamic acid, phthalic acid and 2-hydroxyaniline, respectively. The values of k1 and k2 at different content of CH3CN have been calculated from a kinetic equation based upon a reaction scheme with two irreversible pseudo-first-order consecutive reaction paths. The values of k1/k2 are > 104 within CH3CN content range 1% – 80% v/v in mixed aqueous solvents. The intermediate hydrolysis product (B) exists in 72% dianionic, 27.9% monoanionic and 0.1% nonionic form under the present experimental conditions. Both dianionic and monoanionic forms of B are non-reactive while the nonionic form of B is reactive towards hydrolysis under such conditions.
  9. Yusoff, M.H.M., Hassan, H.A., Hashim, M.R., Abd-Rahman, M.K.
    ASM Science Journal, 2008;2(2):139-148.
    MyJurnal
    The fabrication tolerance of a short and compact low refractive index grating waveguide polarisation splitter based on the principle of resonant tunnelling was analyzed in this study. The design utilised two grating waveguides with an intermediate conventional waveguide layer. The design and optimisation were conducted using the quasi 2-D effective index solver with global search algorithm. An optimum device operating at 1.55 μm wavelength was obtained at a length of 340 μm. The splitting ratios were calculated to be 36 dB and 15 dB, and the overall device transmission efficiencies, after considering the three-dimensional waveguide leakage loss, were estimated at 88% and 83% for tranverse magnetic and tranverse electric polarisation, respectively.
  10. Al-Araji, L., Rahman, R.N.Z.A., Basri, M., Salleh, A.B.
    ASM Science Journal, 2008;2(1):45-56.
    MyJurnal
    The growth and production of biosurfactant by P. seudomonas aeruginosa (181) was dependant on nutritional factors. Among the eleven carbon sources tested, glucose supported the maximum growth (0.25 g/L) with the highest biosurfactant yield and this was followed by glycerol. Glucose reduced the surface tension to 35.3 dyne/cm and gave an E24 reading of 62.7%. Butanol gave the lowest growth and had no biosurfactant production. For the nitrogen sources tested, casamino acid supported a growth of 0.21 g/L which reduced the surface tension to 41.1 dyne/cm and gave an E24 reading of 56%. Soytone was assimilated similarly, with good growth and high biosurfactant production. Corn steep liquor gave the lowest growth and did not show any biosurfactant activity.
  11. Muhd-Yassin, S.Z., Harun, S.W., Ahmad, H., Abd-Rahman, M.K.
    ASM Science Journal, 2008;2(2):163-168.
    MyJurnal
    An efficient erbium/ytterbium co-doped fibre amplifier was demonstrated by using a dual-stage partial doublepass structure with a band-pass filter (BPF). The amplifier achieved the maximum small signal gain of 56 dB and the corresponding noise figure of 4.66 dB at 1536 nm with an input signal power and total pump power of –50 dBm and 140 mW, respectively. Compared with a conventional single-stage amplifier, the maximum gain enhancement of 16.99 dB was obtained at 1544 nm with the corresponding noise figure was improved by 2 dB. The proposed amplifier structure only used a single pump source with a partial double pass scheme to provide a high gain and dual-stage structure to provide the low noise figure.
  12. Othman, M., Ahmad, K.
    ASM Science Journal, 2008;2(2):183-183.
    MyJurnal
    Comet Lulin was discovered by Lin Chi-Sheng and Ye Quanzhi using the 16-inch telescope at Lulin Observatory in Nantou, Taiwan in 2007. According to Brian Marsden of the Smithsonian Astrophysical Observatory, it reached its perihelion on 10 January 2009 at a distance of 113 million
    km from the Sun. It moves in a very nearly parabolic retrograde (‘backwards’ compared to the movement of the planets) orbit at an inclination of 1.6 degrees from the ecliptic (“Newfound Comet Lulin to Grace Night Skies”). http://www.space.com/spacewatch/090206-ns-cometlulin.html). It passed nearest to the Earth at a distance of 61 million km on 23 February 2009.
  13. Harun, S.W., Hofmann, P., Schulzgen, A., Li, L., Peyghambarian, N., Ahmad, H.
    ASM Science Journal, 2008;2(2):149-152.
    MyJurnal
    A distributed feedback fibre laser made of highly Er-Yb co-doped phosphate glass fibre was demonstrated experimentally. The 45 mm long fibre laser device operated at 1540 nm with more than 50 dB side mode suppression ratio. However, the output power was still relatively lower due to un-optimized grating structure and thermal management.
  14. Mahdi, M.A., Sheih, S.J., Al-Mansoori, M.H., Zamzuri, A.K., Adikan, F.R.M.
    ASM Science Journal, 2008;2(2):115-122.
    MyJurnal
    A four-stage erbium-doped fibre amplifier with the gain bandwidth of 35 nm is demonstrated. The amplifier was designed to include a dispersion compensating module to compensate the accumulated dispersion by signals. The amplifier design permited some dynamic features such as the amplifier’s gain could be adjusted from 15 dB to 30 dB by varying the input signal power from –26 dBm to 8 dBm. The maximum output power of 23 dBm was obtained with a maximum allowable gain flatness of 1.5 dB.
  15. Mahdi, M.A., Md. Ali, M.I., Ahmad, A., Zamzuri, A.K.
    ASM Science Journal, 2008;2(2):123-127.
    MyJurnal
    In this paper a study on the wideband double-pass Raman fibre amplifier with mirror as the pump reflector is reported. The pump lights at 1435 nm and 1455 nm were launched in a co-directional manner with respect to the input signal. The double-pass direction of the signal was achieved through a fibre loop mirror constructed using an optical circulator. It was shown that multiple signal amplification was achieved without any disturbance of stimulated Brillouin scattering.
  16. Manimaran, R., Abdul-Rashid, H.A.
    ASM Science Journal, 2008;2(2):133-137.
    MyJurnal
    This paper proposes a signal-to-noise-ratio (SNR) improvement by using an external phase modulator that allowed flexible control of the spectrum amplitude by varying the modulation index for linewidth measurements. Compared with the conventional self-heterodyne detection technique, the results obtained in this study showed an SNR improvement as high as 10 dB. This 10 dB improvement in SNR could help to reduce the usage of a particular length of a single mode fibre (normally about 50 Km) when measuring a linewidth in the region of 10 kHz.
  17. Ibrahim, R.W., Darus, M.
    ASM Science Journal, 2008;2(1):93-100.
    MyJurnal
    We have considered a fractional integral operator in this study. By using this integral operator we obtained a Briot-Bouquet superordination and sandwich theorem.
  18. Kamarudin, K.S.N., Chieng, Y.Y., Hamdan, H., Mat, H.
    ASM Science Journal, 2008;2(1):35-44.
    MyJurnal
    The importance of zeolite surface area and pore volume in adsorption processes has been much reported in literature. In addition to that, structural framework and pore network system may also influence the adsorption capacity and selectivity of methane on zeolite. This paper discusses the characteristics of methane adsorption based on several physical properties of the adsorbents such as surface area, pore volume, pore network system and its interaction with adsorbate. The study, using FTIR spectroscopy showed that the adsorbed methane at room temperature was detected in the FTIR region between 3200 cm–1 – 1200 cm–1. Based on the physical properties of the adsorbents and the FTIR spectra of adsorbed methane, the surface area was not the only factor that determined methane adsorption; in fact the type of pore network system of the adsorbent also affected the interaction, thus affecting the adsorption of methane in zeolite.
  19. Djauhari, M.A.
    ASM Science Journal, 2016;9(2):1-8.
    MyJurnal
    The paradigm that mathematics is a subject to be taught and learned is not correct. Mathematics is to be
    produced. However, without hermeneutics, it would be difficult to do so. Unfortunately, hermeneutics was
    all that have been neglected in mathematics education. Meanwhile, only with hermeneutics, teaching
    and learning mathematics and also research in mathematics could flourish and be fruitful. Without it,
    it would be extremely hard for students to come up with a new creation in mathematics. This paper
    aims to shift the paradigm of mathematics education from learning (only) of mathematics into producing
    mathematics. Some examples are presented to illustrate the power of hermeneutics in developing
    mathematical imagination, ideas, and creativity towards mathematical discovery or invention.
  20. S.P. Woo, I.H. Siti, Y. Zulfigar, S.H. Tan
    ASM Science Journal, 2013;7(2):167-171.
    MyJurnal
    The unsustainable harvesting of sea cucumbers in the Straits of Malacca poses a danger of collapsing population of this marine resource. Recent survey revealed the absence of commercially important sea cucumber species like Stichopus horrens was alarming since there were a lot of taxonomical complications in identifying species from this genus. The knowledge of taxonomy and ecology is an integral part in determining resource management strategies and conservation of marine resources like sea cucumber.
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