bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of User Selected Conditions on Modelling of Dynamic Systems Using Adaptive Fuzzy Model
Authors: Yaacob Mohd Shafiek , Jamaluddin Hishamuddin
Published: January 2013

Kertas kerja ini membincangkan sifatâ€“sifat utama satu pengenalpasti sistem iaitu model kabur suai yang dilatih dengan algoritma perambatan balik. Model kabur piawai berasaskan aturan kabur telah digunakan untuk mengenal pasti sistem dinamik diskret tak lelurus. Kaedah pemilihan pemboleh ubah masukan, bilangan aturan dan kadar latihan ada dibincangkan dengan ringkas. Tiga kaedah pemilihan parameter awal telah dipertimbangkan, iaitu kaedah pemilihan dalam talian, luar talian dan rawak. Aspek pelaksanaan dan pengiraan algoritma ini turut diketengahkan. Tiga contoh sistem dinamik tak lelurus telah digunakan untuk menunjukkan kesanâ€“kesan kaedah latihan yang dipilih oleh pengguna dalam proses pengenalpastian ini. Keputusan daripada proses pengenalpasti model ini menunjukkan ia boleh menganggarkan sistem dinamik dengan baik. Ujian pengesahan model secara sekaitan telah digunakan untuk mengesahkan kecukupan model berkenaan.

Kata kunci: Pengenalpasti sistem; model kabur; algoritma perambatan balik; sistem dinamik.

In this paper, major properties of an adaptive fuzzy model as a system identifier when trained by the backâ€“propagation algorithm are discussed. The standard ruleâ€“based fuzzy models were used to identify discreteâ€“time nonlinear dynamic systems. The method of selection of the input variables, the number of rules, and the learning rate are briefly discussed. Three methods for choosing the initial parameter of the fuzzy model are considered, namely the onâ€“line, the offâ€“line and the random initial parameters. The implementation and the computational aspects of the training algorithm are also highlighted. Three examples of discreteâ€“time nonlinear systems are used in the simulation study to show the effects of user selected conditions on the identification process. The results of the identification procedure show that they approximate the dynamic plants quite well. The correlation based model validity tests are used to validate the identified fuzzy model.

Key words:System identification; modeling; fuzzy system; back-propagation algorithm; dynamic systems.
The Development of Fluxgate Magnetometer for Non–Destructive Measurement
Authors: Chew Soon Leong , Ahmad Rashdi Shah , Jaafar Rosly
Published: January 2013

Pengukuran tanpa musnah bahan feromagnet dan gangguan medan magnet frekuensi rendah memerlukan penderia medan magnet yang mempunyai kepekaan yang tinggi dan stabil. Magnetometer yang berasaskan prinsip fluxgate dan memenuhi ciri-ciri yang diperlukan telah dibina dengan menggunakan teras gelang ferit. Teras gelang ferit ini dipacukan dengan sumber arus untuk mencapai keadan histerisis. Gelung pengesan yang dililit merentasi gelang ferit akan mengesan perubahan medan magnet yang berlaku pada gelang ferit tersebut. Teknik pengesanan yang digunakan adalah berasaskan pengesanan harmonik kedua oleh suatu pengesan fasa. Penderia fluxgate yang dibina adalah murah mudah dibina, mampu mengesan arah medan magnet dan tahan lasak.

Kata kunci: Fluxgate; penderia medan magnet; histerisis; feromagnet

Non–Destructive measurements of ferromagnetic material and low frequency magnetic flux distrubance require a highly sensitive and stable magnetic sensor with directional capabilities. A magnetometer based on fluxgate principle that meets the requirement had been developed using a ferrite ring core. The ferrite ring core is excited by an excitation current source to achieve hysteresis condition. The pick up coil that is wound across the ring core will pick up the magnetic flux generated in the ring core. This sensing method is based on the conventional type of fluxgate magnetometer with detection of second harmonics by a phase sensitive detector. Major advantages of the fluxgate magnetometer are low cost, directional, easy to construct, reliable and rugged.

Key words: Fluxgate; magnetic sensor; hysteresis; ferromagnetic
Physico–Chemical Characterization of Vanadium–Phosphorus–Oxide Catalysts Prepared in Organic and Aqueous Medium
Authors: Taufiq–Yap Yun Hin , Looi Ming–Hoong , You–Ngiik Wong D. , Hussien Mohd. Zobir
Published: January 2013

Dua mangkin vanadium–fosforus–oksida (VPO) telah disediakan dengan menggunakan kaedah yang dikenali sebagai medium ‘organik’ dan ‘akueus’. Pencirian mangkin ini telah dilakukan dengan menggunakan luas permukaan BET dan keliangan, analisis gravimetrik terma (TGA/DTG) dan penurunan berprogram suhu (TPR). Hasil kajian menunjukkan mangkin VPO yang disediakan dalam media organik memiliki luas permukaan yang lebih besar, mobiliti oksigen kekisi yang lebih tinggi dan mempunyai tapak penurunan yang lebih banyak.

Kata kunci: Vanadium-fosforus-oksida; pengoksidaan butana; penurunan berprogram suhu

Two vanadium–phosphorus–oxide (VPO) catalysts were prepared by two different methods known as organic and aqueous medium. Characterization of these catalysts were carried out by BET surface area and porosity, gravimetry thermal analysis (TGA/DTG) and temperature programmed reduction (TPR). The result show that VPO catalyst prepared in organic medium gave larger surface area, higher lattice oxygen mobility and has a greater reduction site.

Key words: Vanadium-Phosphorus-Oxide; butane oxidation; maleic anhydride; temperature-programmed reduction.
Degradasi Gas Benzena Melalui Proses Pemangkinanfoto Saput Tipis TiO2
Authors: Wan Abu Bakar Wan Azelee , Othman Mohd Yusof , Mohd Saiyudi Noor Khaida Wati , Tanaka Keiichi
Published: January 2013

Pengoksidaanfoto benzena fasa gas menggunakan saput tipis TiO2 yang disinari lampu ultralembayung telah dikaji. Saput tipis ini disediakan melalui kaedah celup angkat menggunakan sol–gel TiO2. Tindak balas yang sama juga telah dijalankan menggunakan saput tipis TiO2 yang didop dengan Cu2+ dan Fe3+ dengan nisbah mol TiO2 terhadap ion logam 1:0.005, 1:0.001, 1:0.0005 dan 1:0.0003. Hasil kajian menunjukkan mangkin TiO2 dengan pancaran cahaya UV (354 nm) mendegradasikan gas benzena sebanyak 90% dalam masa 55 minit. Walau bagaimanapun penambahan ion Fe3+ dengan nisbah 1:0.0005 meningkatkan peratusan degradasi benzena kepada 98% dalam masa 55 minit, sebaliknya penambahan Cu2+memberikan kesan negatif kepada aktiviti foto TiO2. Kajian juga memperoleh satu nilai optimum dengan aktiviti pemangkinan adalah tertinggi bagi kedua-dua ion Fe3+ dan Cu2+. Pengaruh panjang gelombang cahaya ke atas aktiviti foto TiO2 juga telah dikaji dengan menggunakan mangkin TiO2 dop Fe3+ dengan nisbah optimum. Hasil kajian menunjukkan bahawa degradasi gas benzena meningkat dengan pengurangan tenaga cahaya yang dipancarkan.

Kata kunci: Pemangkinanfoto; pengoksidaanfoto; saput tipis; TiO2

The gas phase photooxidation of benzene was investigated using TiO2 thin film irradiated with UV light source. The thin film was prepared via TiO2 sol gel dip coating method. The same reaction was also carried out using TiO2 doped with Cu2+ and Fe3+ with 1:0.005, 1:0.001, 1:0.0005 and 1:0.0003 mole ratios. The results showed that 90% of benzene was degraded after 55 minutes UV (354 nm) irradiation of the TiO2 thin film. However the addition of Fe3+ ions with 1:0.0005 mole ratio degraded 98% of benzene within 55 minutes. In contrast, Cu2+ ions however give a detrimental effect to the photoactivity of TiO2. An optimum ratio of dopant, where TiO2 showed the highest activity, was determined for both Fe3+ and Cu2+. The effect of different wave-length light source was also carried out using TiO2 doped Fe3+ with optimum ratio. The degradation of benzene was found to increase with decreasing light energy.

Key words: Photocatalysis; photooxidation; TiO2 thin film
Generation of Pulse Width Modulation (PWM) Signals for Three-Phase Inverter Using a Single-Chip Microcontroller
Authors: Salam Zainal , Mohammad Salim Khosru
Published: January 2013

Artikel ini menerangkan penggunaan pengawal mikro serbaguna untuk menjana denyut–denyut modulasi lebar jalur untuk penyongsang tiga fasa. Kelebihan utama teknik ini adalah keringkasan perkakasan – hanya sebuah pengawal mikro dengan peralatan dalaman sahaja diperlukan. Hasilnya adalah sebuah sistem yang ringkas, murah dan dapat dipercayai. Setelah prototaip penyongsang menggunakan pengawal mikro Siemens 80C167 telah dibangunkan dan beberapa hasil ujian diberikan.

Kata kunci: Pengawal mikro; penyongsong; denyut modulasi lebar jalur; elektronik kuasa.

This paper describes the use of a general purpose microcontroller to generate the pulse width modulation (PWM) pulses for a three–phase inverter. The main feature of the work is the simplicity of the hardware – only a fixed point microcontroller with its associated internal peripheral is required. This result in an extremely simple, low-cost and reliable system. A laboratory inverter prototype using a Siemens 80C167 microcontroller is developed and typical results are presented.

Key word: Microcontroller; inverter; pulse width modulation; power electronics, renewable energy.
Pengukuran Halaju Susuk: Kaedah Sekaitan Silang dalam Proses Tomografi
Authors: Abdul Rahim Ruzairi , Rahmat Mohd. Fuaad , Abdul Wahab Norhasliza
Published: January 2013

Kertas kerja ini membincangkan untuk melihat sejauhmana kesan penderia optik yang diletakkan secara susunan hulu dan hilir dapat memberikan satu keputusan dalam bentuk paparan graf halaju bagi fungsi sekaitan silang apabila pepejal kering dijatuhkan ke dalam sebatang paip.
Formal Specification of a Wall-Climbing Robot Using Z – A Case Study of Small-Scale Embedded Hard Real-Time System
Authors: Mohamad Radziah , Abg. Jawawi Dyg. Norhayati , Deris Safaai , Mamat Rosbi
Published: January 2013

Aktiviti menguji sama ada sistem masa nyata memenuhi spesifikasi masa dan keserempakan adalah sangat penting. Salah satu bidang penyelidikan dalam bidang keboleh-percayaan perisian ialah teknik formal yang cuba untuk membuktikan kesahihan sesuatu atur cara dengan spesifikasinya. Oleh kerana masa dan keserampakan merupakan aspek yang penting dalam sistem masa nyata, keperluan untuk menggunakan teknik formal sebagai teknik untuk mengesahkan aspek masa dan keserempakan ini adalah amat tinggi. Kertas kerja ini mengkaji proses membina spesifikasi formal untuk sistem masa nyata berskala kecil dengan menggunakan teknik Z. Spesifikasi formal yang dibangunkan di dalam kertas kerja ini diharap dapat membantu proses penganalisisan fasa reka bentuk di awal proses pembangunan sistem. Kertas kerja ini juga diharap dapat menjadi rujukan kepada projek–projek teknik formal yang akan datang terutamanya projek yang berkaitan dengan sistem masa nyata berskala kecil.

Kata kunci: Kebolehpercayaan perisian; spesifikasi formal; Z; masa nyata; sistem berskala kecil.

The task of checking whether a real–time system satisfies its timing and concurrency specifications is extremely important. One major area of research addressing software reliability aspect is called formal method, which attempts to prove the correctness of programs with respect to system specifications. Since, timing and concurrency properties can very important in the operation of real–time systems, there is a need for applying formal methods to verify timing properties. This paper investigates the process of building a formal specification of a small-scale embedded hard real–time systems using Z. It is expected that the formal specification presented in this paper can provide assistance in analysing design trade–offs early in the development process. It is also expected that this paper can act as the foundation for any upcoming formal methods related project especially for small-scale real–time systems project.

Key words: Software reliability; formal specification; Z; hard real-time; small-scale systems
Treated Effluent in Concrete Technology
Authors: Ooi Soon Lee , Salim Mohd Razman , Ismail Mohammad , Ali Md. Imtiaj
Published: January 2013

In this paper, the feasibility of using treated effluent for concrete mixing was studied. Treated effluent from sewage treatment plants in Malaysia is currently being wasted through direct discharge into waterways. With proper water quality control, this treated effluent can also be considered as a potential water resource for specific applications. Two tests were carried out namely compressive strength test and setting time to determine the feasibility of using treated effluent for concrete mixing. The results were compared against the test conducted on control specimens which used potable water. The results showed that treated effluent increases the compressive strength and setting time when compared with potable water.

Key words: treated effluent; mixing water; compressive strength; setting time; concrete technology.
Effects of Feed Pressure and Retentate Flow Rate on the Performance of Locally Developed Polysulfone Membrane Oxygen Enrichment System
Authors: Ismail Ahmad Fauzi , Tan Chin Yin , Chan Fook Kiong
Published: January 2013

Pengkayaan oksigen daripada udara persekitaran dengan menggunakan teknologi membran diterima secara meluas di seluruh dunia sebagai teknologi alternatif kepada kaedah konvensional seperti penjerapan ayunan tekanan dan sistem kriogenik. Pemisahan udara menggunakan membran adalah proses yang lebih anjal di mana ia memerlukan pelaburan modal yang rendah, kaedah operasi yang mudah dan murah jika dibandingkan dengan kaedah konvensional. Kajian dan pengujian telah dijalankan ke atas sistem membran gentian geronggang polisulfona, di mana kesan tekanan suapan dan kadar alir baki dikaji. Pada kadar alir malar, pengkayaan telapan meningkat dan kemudian menurun dengan peningkatan tekanan disebabkan oleh kesan perbezaan tekanan merentasi membran mempengaruhi kebolehtelapan lapisan kulit. Manakala pada tekanan suapan malar, nilai pengkayaan telapan maksimum dicapai pada kadar alir maksimum disebabkan oleh peningkatan rintangan penelapan. Nilai maksimum ketulenan telapan oksigen yang diperolehi dalam uji kaji ini ialah 27.2%.

Kata kunci: Pemisahan udara; membran gentian geronggang; pengkayaan oksigen; kebolehtelapan; polisulfona

Oxygen enrichment from surrounding air by using membrane is gaining wide acceptance through out the world today as an alternative to the conventional methods such as pressure swing adsorption and cryogenic system. Air separation using membrane is a more flexible process that requires lower capital investment and simple operation. Studies and testing had been performed on a locally new developed polysulfone hollow fiber membrane system, where effects of feed pressure and retentate flow rate on the oxygen enrichment were observed. At constant retentate flow rate, permeate enrichment increased and then decreased with pressure due to the effect of pressure difference across the membrane, which affects the permeability of the skin layer. While at constant pressure, the highest permeate enrichment value was obtained at highest retentate flow rate due to the increase of permeation resistance. The highest oxygen purity obtained in this experiment was 27.2% and the O2 permeate enrichment was 1.295.

Key words: Air separation; hollow fiber membrane; oxygen enrichment; permeability; polysulfone
Assessment of Potential Oil and Gas Exploration Investments: Management Perspective
Authors: Abd. Razak Razif
Published: January 2013

Assessment of potential oil and gas exploration investments is a crucial initial step for petroleum companies to ensure the success of the investments. The study explores the decision–making processes of the upstream investment in U.S. petroleum companies. Two hundred and twenty–one high–level decision-makers representing 221 U.S. petroleum companies completed mail questionnaires concerning decision–making processes in assessing potential oil and gas exploration investment employer by their firms. The result of the study established and empirically described the management view of the current practices of assessing oil and gas exploration investments. The study also identifies the relationships between the decision–making processes and the performance of the company.
A Review Of New Business Emergence in the Building and Construction Sector and Recent Australian Experience
Authors: Manley K.J. , Marceau J.
Published: January 2013

The article reviews the value of new business activity to industry growth, in the context of the building and construction (B&C) sector. A brief empirical analysis of the pattern of new business growth in the Australian B&C sector between 1997 and 1998 is presented. It is found that significant new business entry has taken place in many of industries making up the sector. Further research is required to extend this initial work. In particular, it would be useful to explore in more depth, the value of particular patterns of new business activity within the sector.

Key Words: Australia; new firms; firm entry; industry growth; innovation
Pluralism in Terrace Housing Community Through Ethnic Garden
Authors: Said Ismail
Published: January 2013

Landskap warisan adalah simbol peradaban dan nilai kepercayaan sesuatu kumpulan etnik dalam satu komuniti. Ia dibentuk oleh ilham dan daya usaha manusia yang menunjukkan perkaitan erat antara kelakuan manusia dengan alam lingkungannya. Landskap ini amat bermakna kepada komuniti rumah teres di Semenanjung Malaysia yang dikomposisi oleh berbilang etnik termasuk Melayu, Cina dan India. Kertas kerja ini membincang peranan landskap warisan kepada komuniti rumah teres yang secara langsung dan tidak langsung mengintegrasi penduduk dan menyumbang rasa kekitaan terhadap komuniti. Ciri–ciri landskap warisan yang diperjelaskan dalam laman–laman etnik rumah teres adalah komposisi tanaman dan pilihan tumbuhan dan aksesori laman. Persamaan dan perbedaan ciri–ciri tersebut menonjolkan bentuk laman sesuatu etnik yang harus diambil kira dalam perancangan landskap komuniti rumah teres.

Cultural–ethnic landscape symbolizes the belief and cultural values of an ethnic group living in a community. The landscape is an expression of people´s idea and work, illustrating intrinsic understanding and relationship of people to their fellow beings and environment. Such landscape is significant to the human community development and more challenging to establish it in a multi–ethnic society such as terrace house neighborhood in Peninsular Malaysia than in homogenous society. This paper discusses the role of ethnic gardens created by terrace housing residents towards integration and sense of belonging to their living neighborhood. The making of the residential gardens by Malays, Chinese and Indians are influenced by both cultural values and functional needs. There are few similarities and differences in planting composition, plant selection and garden accessories that reflect the strength of ethnicity and yet allow sharing of garden produce and create a sense of place for the community. This pluralism can be seen as positive phenomena to harmonize multi–ethnic society living in terrace housing neighborhoods in Peninsular Malaysia.
Real-Time Velocity Profile Generation of Powder Conveying Using Electrodynamic Transducer
Authors: Rahmat Mohd Fua'ad , Fazalul Rahiman Mohd. Hezri
Published: January 2013

Kaedah pengukuran tomografi ini bertujuan mengkaji pengukuran profil halaju pengaliran dalam paip secara talian terus ataupun masa sebenar bagi pengaliran yang menegak dan melintang. Secara umumnya, pengukuran yang dibuat adalah berdasarkan cas elektrostatik yang dijana oleh hasil pergerakan serbuk pepejal kering di dalam paip. Pengumpulan cas–cas ini akan dikesan oleh dua rangkaian penderia elektrodinamik. Konsep asas yang digunakan oleh penderia–penderia ini adalah penukaran keamatan cas yang dihasilkan kepada magnitud voltan yang setara. Penderia–penderia ini akan ditempatkan di luar ukur lilit permukaan paip dan jarak antara dua rangkaian penderia ini telah ditetapkan. Isyarat–isyarat voltan yang dihasilkan oleh penderia akan disampel, dimanipulasi dan dipaparkan pada skrin komputer dengan program aplikasi yang dibangunkan melalui pengaturcaraan menggunakan Microsoft Visual Basic 6.0. Keupayaan utama aplikasi ini adalah kebolehannya mengintegrasikan sistem pengukuran ini dalam masa sebenar yang sebelum ini tidak dapat dilakukan.

Kata kunci: Tomografi; elektrodinamik; masa sebenar; profil halaju; antara muka

This methodology explores the probability in determining the real–time velocity profiles of a vertical and horizontal flow. Generally, the measurement is based on the electrostatic charges produced by dry solid powder during their movement in the flow rig and accumulated at the sensors’ electrode. Two arrays of dedicated electrodynamic sensors are used as static–to–electrical signal converter and they are located at the pipe wall. The sensors generated electrical signal corresponding to the amount of flow it detects and this is based on the fact that the amount of flow contributes to the level of the static charges accumulated at the sensors. The collected data is retrieved and manipulated by an application program, which is developed using Microsoft Visual Basic 6.0. The application features the ability to obtain velocity in real–time mode, which is previously unrealisable.

Key words: Tomography; electrodynamic; real-time; velocity profile; interfacing
Speaker-Independent Malay Syllable Recognition Using Singular and Modular Neural Networks
Authors: Ting Hua Nong , Yunus Jasmy , Shaikh Salleh Sheikh Hussain
Published: January 2013

This paper describes a design procedure for a fuzzy logic based power system stabilizer (FLPSS) and adaptive neuro–fuzzy inference system (ANFIS) and investigates their robustness for a multi–machine power system. Speed deviation of a machine and its derivative are chosen as the input signals to the FLPSS. A four–machine and a two–area power system is used as the case study. Computer simulations for the test system subjected to transient disturbances i.e. a three phase fault, were carried out and the results showed that the proposed controller is able to prove its effectiveness and improve the system damping when compared to a conventional lead–lag based power system stabilizer controller.
Development of Reactive Control Strategy for Multi-Agent Mobile Robotics System
Authors: Ahmad Mohd Ridzuan , M. Amin Shamsudin H. , Mamat Rosbi
Published: January 2013

Multi–agent system is one the most popular research interests in robotics nowadays. Imagine for a swarm of robots, what kind of intelligence can we build now? This question arises from emulating biological systems. How is it that colonies of small ants can work together to perform a difficult task that single ant cannot do it alone? How might collections of simple robots aid us in human endeavours? By examining these questions, one of the common characteristics shared by each agent is in agent simplicity. Simplicity in control means that the robots are provided with direct commands in order to execute the action. It doesn’t need to gather all information from various sensors to plan its action like deliberative control which is also known as sensors fusion that clearly required a lot of computational time and also the mapping that its produces might not valid at the time when changes occurs between the time it gathers the information and the time it plans its actions. Instead, intelligence will arise when these simple agents work together to perform some complex task cooperatively. By examining the major control architectures available in robotics area, subsumption–based reactive control architecture gives the tools as required. Priority–based scheme is used in arbitration level to select which behaviour to run. In this paper decentralised reactive control architecture was used to justify the communication based simple control architecture can perform complex task like carrying load and navigate.

Key words: Multi-agent system; reactive control architecture; control algorithm
Penyelesaian Masalah Penjadualan Dinamik dengan Menggunakan Pendekatan Taakulan Berasaskan Kes
Authors: Zakaria Zalmiyah , Deris Safaai
Published: January 2013

Masalah penjadualan waktu universiti telah menjadi satu masalah yang membebankan pihak pengurusan akhir–akhir ini. Persekitaran aktiviti akademik yang sentiasa berubah menyebabkan berlakunya perubahan kepada jadual semasa. Kebanyakan sistem penjadualan yang sedia ada tidak dapat menyelesaikan masalah ini. Oleh yang demikian, taakulan berasaskan kes (CBR) telah dipilih untuk bertindakbalas terhadap sebarang perubahan di dalam sistem penjadualan untuk memastikan penyelesaiannya sentiasa selari dengan perkembangan persekitaran yang dinamik.

Kata kunci: Taakulan berasaskan kes; taakulan berasaskan kekangan; masalah pemuasan kekangan; penjadualan reaktif; penjadualan universiti
Characterization of Modified HZSM–5 with Gallium and its Reactivity in Direct Conversion of Methane to Liquid Hydrocarbons
Authors: Saidina Amin Nor Aishah , Ali Asmadi
Published: January 2013

Mangkin zeolit HZSM–5 diubahsuai secara kaedah pertukaran ion berasid bagi menghasilkan mangkin zeolit Ga–HZSM–5. Aktiviti bermangkin bagi HZSM–5 dan Ga–HZSM–5 dikaji pada suhu tindak balas 800°C dan halaju ruang jaman masa (GHSV) 7500 jam–1. Mangkin HZSM–5 dan Ga–HZSM–5 dicirikan secara XRD, NMR, Penjerapan Nitrogen dan TPD. Hasil pencirian menunjukkan aluminium keluar dari kerangka asal. HZSM–5 yang mengandungi galium adalah mangkin yang lebih baik daripada mangkin zeolit HZSM–5 bagi menghasilkan cecair hidrokarbon.

Kata kunci: Ga-HZSM-5; metana; pertukaran ion berasid; cecair hidrokarbon

The HZSM–5 zeolite catalyst was modified by an acidic ion exchange method to produce the Ga–HZSM–5 zeolite catalyst. The catalytic activity of HZSM–5 and Ga–HZSM–5 were studied at reaction temperature of 800°C and gas hourly space velocities (GHSV) of 7500 hr–1. HZSM–5 and Ga–HZSM–5 catalysts were characterized by XRD, NMR, Nitrogen Adsorption and TPD. The characterization results revealed that aluminium was removed from the parent framework. Gallium loaded HZSM–5 is a better catalyst than HZSM–5 zeolite catalyst to produce liquid hydrocarbons.
Key words: Ga-HZSM-5; methane; acidic ion exchange; liquid hydrocarbons
Experimental Capability of High Resolution O17 using Double Rotation on Crystalline Sodium Enneagermanate
Authors: Hussin R. , Dupree R. , Samoson A. , Bull L.M.
Published: January 2013

Sampel kristal sodium enneagermanate telah dikaji dengan menggunakan penspinan sudut ajaib (MAS) dan putaran berganda (DOR) pada dua medan magnet yang berbeza. Jumlah anjakan kimia yang dicerap pada dua medan magnet telah digunakan untuk mengira anjakan kimia isotropik berserta dengan nilai pemalar gandingan (CQ = e2qQ/h) dan parameter tak simetri empat kutub (Î·). Nilai anjakan kimia isotopik dan pemalar gandingan itu telah digunakan dalam komputer simulasi untuk menentukan bentuk spektra penspinan sudut ajaib. Melalui kaedah tersebut parameter CQ dan Î·, telah ditentukan untuk setiap fasa kristal sampel sodium enneagermanate. Kaedah putaran berganda (DOR) telah menunjukkan keupayaan yang sangat tinggi dengan memperlihatkan spektrum oksigen-17 resolusi tinggi, untuk menentukan struktur unit yang terdapat dalam sampel kristal sodium enneagermanate. Kristal sodium enneagermanate telah dikaji untuk menentukan hubungan yang berlaku di antara parameter gandingan empat kutub 17O dengan kedudukan kekisi oksigen didalam sampel. Hasil yang diperolehi ini pula boleh digunakan untuk kajian yang selanjutnya untuk menentukan struktur kaca oksida yang lain dan kaca yang berasaskan germanate dengan menggunakan kaedah 17O keadaan pepejal resonan magnet nukleus.

Kata kunci: kristal sodium enneagermanate; penspinan sudut ajaib; putaran berganda; oksigen-17 ; resonan magnet nukleus

We have studied sodium enneagermanate crystal using both magic angle spinning (MAS) and double rotation (DOR) at two magnetic field strengths. Using equation for the total shift observed at two field strengths, the chemical shift is uniquely determined together with a product of the quadrupolar coupling constant (CQ = e2qQ/h) and the quadrupolar asymmetry parameter (Î·). We demonstrate a computer simulation that uses the isotropic shifts and quadrupolar products as constraints and provides simulations of overlapped magic-angle spinning line shapes. In this way the quadrupolar parameters, CQ and Î·, are determined separately for each crystallographic site of crystalline sodium enneagermanate. High resolution DOR spectra of oxygen-17 nuclei in sodium enneagermanate crystal illustrate the experimental capabilities. Crystalline studies of sodium enneagermanate is one of the structural data for confirming the correlations between the measured 17O quadrupolar coupling parameters and the oxygen environment. The result of these studies should provide insight to further investigation using 17O solid state NMR to study the structure of other oxide glasses and as well as other germanate-based glasses.

Key words: sodium enneagermanate crystal; magic angle spinning (MAS); double rotation (DOR); oxygen; nuclear magnetic resonance (NMR)
A Comparison of Plotting Formulas for the Pearson Type III Distribution
Authors: Shabri Ani , Nasir Ani Farid
Published: January 2013

Formula kedudukan memplot tanpa bias dibincangkan untuk dipadankan dengan taburan Pearson 3 (PIII). Penganggar kuantil kedudukan memplot terbaik seharusnya tanpa bias dan mempunyai min punca ralat terkecil antara penganggar-penganggar yang lain. Pekali korelasi kedudukan memplot digunakan sebagai ujian pemadanan cocokan untuk menguji hipotesis taburan PIII. Hasil keputusan menggunakan data aliran maksimum daripada Semenanjung Malaysia berdasarkan ujian PPCC menunjukkan rumus kedudukan memplot menghasilkan plot kebarangkalian yang linear dengan pekali korelasi menghampiri satu. Berdasarkan punca min ralat kuasa dua dan punca min ralat mutlak, formula Weibull adalah terbaik antara formula-formula yang lain.

Kata kunci: Kedudukan Memplot; kuantil; tanpa bias; punca min ralat kuasa dua

Unbiased plotting position formulas are discussed to fit the Pearson Type 3 distribution (PIII). The best quantile estimate made from the plotting position should be unbiased and should have the smallest root means square error among all such estimates. Probability plot correlation coefficient (PPCC) is used to evaluate goodness of fit to test the PIII distribution hypothesis. Results obtained using the annual maximum flow data from Peninsular of Malaysia based on PPCC show the plotting position formulas consistently produced linear probability plots with correlation coefficient near to one. Based on root mean square error (RMSE) and root mean absolute error, the Weibull formula performs better than the other formulas.

Key words: Plotting Position; quantile; unbiased; root means square error
Anggaran Parameter Dinamik Penjana Menggunakan Teknik Pengoptimuman Kecerunan
Authors: Mat Zali Samila , Mohamed Azah , Hussain Aini , Ariffin Aznan Ezraie
Published: January 2013

Kertas kerja ini membentangkan kaedah anggaran parameter dinamik bagi penjana dengan menggunakan teknik pengoptimuman kecerunan. Perancangan dan pengoperasian sistem kuasa lazimnya berpandukan keputusan simulasi sistem kuasa yang bergantung kepada kejituan parameter model bagi penjana, penguja dan juga penguasa. Oleh itu, nilai parameter yang tepat dan jitu perlu digunakan dalam kajian simulasi supaya keputusan simulasi adalah mirip sistem sebenar dan perancangan sistem kuasa yang cekap dan ekonomik dapat dilaksanakan. Walau bagaimanapun, dari masa ke semasa nilai parameter model akan berubah dari spesifikasi nilai awalnya disebabkan berlaku perubahan pada keadaan penjana tersebut. Untuk menangani masalah ketidakjituan model penjana, satu teknik anggaran parameter dinamik yang sistematik telah dibangunkan dan diuji ke atas satu sistem ujian. Keputusan nilai anggaran yang memuaskan telah diperolehi dengan purata ralat parameter anggaran kurang daripada 6%.

Kata kunci: Anggaran parameter; model penjana sinkroni; teknik pengoptimuman

This paper presents a new method for estimating the generator dynamic parameters using the gradient optimisation technique. Power system planning and operation studies normally rely on the power system simulation results which greatly depend on the accuracy of the model parameters. Therefore, accurate and exact parameter values are required in power system simulation studies so that correct simulations of actual power system behaviour can be obtained and efficient as well as economical power system planning can be implemented. However, model parameters currently used may have changed from its initial values with time due to equipment changes and this results in inaccurate model parameters. To overcome the problem of inaccurate generator model parameters, a systematic approach for estimating the generator parameters have been developed and tested on a test system. Satisfactory results of the estimated values were obtained with an average error of the estimated parameters of less than 6%.

Key words: Parameter estimation; synchronous generator model; optimization technique
Using Voting Technique In Mobile Robot Behavior Coordination For Goal-directed Navigation
Authors: Tan Chee Kwong , M. Amin Shamsudin H. , Mamat Rosbi
Published: January 2013

Dalam robot mudah alih dengan kelakuan, pengawalan robot dibahagikan kepada sekumpulan kelakuan yang tertentu. Setiap kelakuan dengan objektif tertentu beroperasi secara bebas untuk menghantar arahan bagi mengawal robot. Namun begitu, kelakuan dengan objektif yang berlainan mungkin berkonflik. Oleh hal yang demikian, koordinasi di antara kelakuan merupakan suatu isi penting. Suatu teknik mengundi telah digunakan untuk mengatasi masalah ini. Setiap kelakuan mengundi untuk suatu set tindakan. Undi sifar menandakan tindakan yang tidak diingini manakala undi satu menandakan tindakan yang paling diingini. Kelakuan menghantar undi untuk mewakili kebolehan tindakan itu untuk mencapai objektif kelakuan. Suatu penentu akan mengumpulkan semua tindakan ini dan pilih tindakan yang paling sesuai dengan memenuhi syarat pareto-optimal. Ini dapat menyelesaikan masalah pemilihan tindakan dan meninggikan kebarangkalian untuk berjaya. Teknik ini telah digunakan dalam robot mudah alih UTM AIBOT. Keputusan eksperimen dan kebolehpercayaan teknik ini telah ditunjukkan.

Kata kunci: Teknik mengundi; koordinasi kelakuan; pemilihan tindakan; robot mudah alih; pelayaran berpandukan matlamat

In behavior-based mobile robot, the control strategy is distributed among a set of specialized behaviors. Each behavior with particular objective runs completely independently to send commands to control the mobile robot. However, behavior with different objectives may generate conflicting command. Therefore, behavior coordination is an important issue. An intelligent voting technique is implemented to solve this problem. Each behavior votes for a set of possible actions, with vote zero is the least desired action and vote one is the most desired action. The behaviors send votes as a possibility for each action set to achieve the objectives of the behaviors. An arbiter then performs command fusion and selects the most favored action that is paretoâ€“optimal. This will solve the action selection problem and improve the probability to succeed. This technique has been implemented on UTM AIBOT mobile robot. The experimental results are presented and the reliability of the technique is shown.

Key words: Voting technique; behavior coordination; action selection; mobile robot; goal directed navigation
A Survey and Comparative Evaluation of Selected off-line Arabic handwritten Character Recognition Systems
Authors: Jumari Kasmiran , A. Ali Mohamed
Published: January 2013

Penggunaan teknologi multimedia dalam bidang pendidikan pada masa kini telah menjadi satu keperluan dalam usaha memantapkan bidang pendidikan selaras dengan arus semasa di alaf yang mencabar ini. Teknologi sebegini harus dimanfaatkan sepenuhnya bagi menjanakan suatu output yang dapat digunakan untuk kebaikan bersama. Melalui multimedia yang interaktif, suasana pengajaran dan pembelajaran menjadi lebih menarik dengan penggunaan elemen multimedia seperti teks, audio, video, grafik dan animasi yang melibatkan kesemua kepekaan manusia. Justeru itu, pelbagai pendekatan atau teori pendidikan harus diimplementasikan dalam perisian multimedia secara berkesan untuk memastikan perisian yang dihasilkan itu mampu meningkatkan kualiti pembelajaran dan pengajaran. Prototaip perisian multimedia yang dibangunkan ini berasaskan pendekatan konstruktivisme mengenai topik Bumi dan Kejadian Siang dan Malam. Pendekatan konstruktivisme dipilih kerana ia mengambil kira konsep awal atau prakonsepsi yang wujud dalam minda pelajar. Seterusnya, penstrukturan semula ide yang melibatkan aktiviti â€˜hands-onâ€™ dan â€˜minds-onâ€™ perlu dilakukan untuk mengembangkan lagi atau mengubah suai ide terdahulu. Kebolehlaksanaan dan keberkesanan prototaip ini dinilai dan secara keseluruhannya ia berada pada tahap sederhana dan ia juga dikenalpasti dapat membantu peningkatan kefahaman pelajar dalam tajuk ini.

Kata kunci: pembangunan perisian multimedia; konstruktivisme; pendidikan sains

Today, the use of multimedia technology is vital in enhancing education system in line with the global challenges of the new millennium. Multimedia technology should be utilized to generate useful products. Interactive multimedia elements like text, audio, video, graphic and animation are powerful tools which can make teaching and learning more interesting by employing various human senses. Educational approaches and theories should be used in designing effective multimedia courseware to ensure that it can increase the quality of teaching and learning. A prototype of multimedia courseware is developed in this study based on constructivist learning theory for a science topic on Earth and Day-Night Phenomena. The constructivism approach is chosen because it, emphasised studentsâ€™ preconception or existing ideas. Restructuring ideas the next phase, involvesd â€˜hands-onâ€™ and â€˜minds-onâ€™ activities with the aim to expand or restructure their existing ideas. The extent to which students have restructured their ideas and gained a new understanding of the concepts were tested in application and reflection phases. The prototype was tested for its feasibility and effectiveness and it appears to promote learning among the respondents.

Key words: courseware development; constructivism; science education
Ketepatan Kaedah Pengekosan Berasaskan Aktiviti (ABC) Berbanding Kaedah Pengekosan Tradisional dalam Pengekosan Produk: Pemangkin Kepada Program 6–Sigma
Authors: Harun Muhammad Adli , Mohd Rohani Jafri , Wan Hamid Wan Harun
Published: January 2013

Para pengurus mungkin tidak menyedari bahawa teknik pengekosan yang digunakan untuk menyediakan laporan kewangan yang mematuhi peraturan percukaian adalah tidak sesuai digunakan bagi tujuan membuat keputusan strategik berkaitan harga jualan, kawalan dan program pengurangan kos. Kertas kerja ini bertujuan menerangkan dan membincangkan kepada pihak pengurusan kesan penggunaan teknik pengekosan tradisional dan seterusnya mencadangkan kaedah pengekosan alternatif iaitu pengekosan berasaskan aktiviti (ABC). Teknik ini menyediakan maklumat yang lebih tepat untuk membuat keputusan. Kajian kes dan analisis telah dilakukan bagi membuktikan bahawa teknik pengekosan tradisional yang diamalkan oleh kebanyakan syarikat menghasilkan keputusan yang kurang tepat berbanding dengan pengekosan ABC. Metodologi pengekosan ABC juga dilihat dapat diintegrasikan dengan metodologi 6–Sigma untuk peningkatan kualiti produk atau proses.

Kata kunci: Pengekosan Berasaskan Aktiviti (ABC); Kaedah Pengekosan Tradisional; 6-Sigma

Managers may not realise that the accounting method that they have been using for stock valuation in financial reporting provides them with inaccurate and sometimes irrelavent information for the purpose of making strategic decisions with regard to pricing, cost control and cost management. The purpose of this paper is to explain and discuss the impact on managers who used information generated from the tradisional costing method in decision making and then suggest an alternative method i.e. activity-based costing (ABC) which provides more accurate and realiable information for decision making. A case study was conducted and an analysis was performed to show that information from the traditional costing method is inaccurate. The methodology of ABC could be integrated into Six Sigma program to become a very powerful tool for driving continuous process and product quality improvement.

Key words: Activity-based Costing (ABC); Traditional Costing Method; Six Sigma
Artificial Neural Network Model for Rainfall–Runoff Relationship
Authors: Harun Sobri , Ahmat Nor Nor Irwan , Mohd. Kassim Amir Hashim
Published: January 2013

Permodelan bagi proses hidraulik dan hidrologi adalah penting apabila dilihat dari sudut kepelbagaian penggunaan sumber air seperti janakuasa hidroeletrik, pengairan, pengagihan bekalan air, dan kawalan banjir. Terdapat banyak kajian sebelum ini yang telah menggunakan kaedah rangkaian neural tiruan atau artificial neural network (ANN) untuk permodelan pelbagai perhubungan tak linear dan kompleks dalam proses hidrologi. Kaedah rangkaian neural tiruan ini telah diketahui bahawa ia merupakan suatu struktur matematik yang mudah ubah (flexible) dan berpotensi untuk menjana dan merumus set-set data masukan dan keluaran yang kurang tepat atau kabur dan tidak dihalusi dengan sempurna. Kawasan kajian adalah kawasan tadahan Sungai Lui (Selangor, Malaysia). Kertas Kerja ini mengutarakan cadangan menggunakan kaedah rangkaian neural tiruan ini bagi mendapatkan jumlah air larian permukaan harian dengan menggunakan hujan sebagai nod masukan kepada model berkenaan. Terdapat dua kaedah telah digunakan dalam pemilihan bilangan nod masukan iaitu seperti yang telah dicadangkan oleh [10] dan [5]. Seterusnya, hasil keputusan yang diperolehi daripada permodelan rangkaian neural tiruan ini dibandingkan dengan hasil keputusan yang diperolehi daripada model HEC-HMS. Didapati bahawa model rangkaian neural tiruan dapat menjana dan merumus perhubungan antara air larian permukaan dan curahan hujan lebih baik berbanding dengan model HEC-HMS.

Kata kunci: hidrologi, rangkaian neural tiruan, hubungan air larian permukaan-curahan hujan

The modelling of hydraulic and hydrological processes is important in view of the many uses of water resources such as hydropower generation, irrigation, water supply, and flood control. There are many previous works using the artificial neural network (ANN) method for modelling various complex non-linear relationships of hydrologic processes. The ANN is well known as a flexible mathematical structure and has the ability to generalize patterns in imprecise or noisy and ambiguous input and output data sets. The study area is Sungai Lui catchment (Selangor, Malaysia). This paper presents the proposed ANN model for prediction of daily runoff using the rainfall as input nodes. The method for selection of input nodes by [10] and [5] is applied. Further, the results are compared between ANN and HEC-HMS model. It has been found that the ANN models show a good generalization of rainfall-runoff relationship and is better than HEC-HMS model.

Key words: hydrologic, artificial neural network, rainfall-runoff relationship
Visual Composition of Malay Woodcarvings in Vernacular Houses of Peninsular Malaysia
Authors: Said Ismail
Published: January 2013

Malay timber houses of Peninsular Malaysia are embellished with carved components that served both functional and aesthetic purpose, thus acting as one of the determining factors in defining the character of the regional architecture. The physical form of woodcarving is governed by four factors, namely principal forms and arrangement, types of incisions and perforations, types of motifs and design principles regulating its composition. The Malay craftsmen of Kelantan, Terengganu, Perak and Negeri Sembilan applied these factors in their carving which resulted in similarities and differences of visual compositions. The major similarities included the aplication of four principal forms of carving patterns and seven shaped of carving arrangements. On the other hand, the differences occurred in types of motifs and types of incisions.
Study of Fractal Bond Connectivity of Neodymium Phosphate Glasses by Ultrasonic Technique
Authors: Budi Agus Setyo , Hussin Rosli , Sahar Md. Rahim
Published: January 2013

Sifat-sifat kenyal untuk kaca neodimium fosfat xNd2O3(1-x)P2O5 dengan komposisi yang berbeza dari 10 hingga 25% mol Nd2O3 telah dikaji melalui kaedah ultrasonik, sebagai fungsi suhu dari 270 K hingga 303 K. Sifat-sifat kenyal yang dikaji antaranya ialah pemalar kekenyalan adiabatik C11, C44 dan modulus pukal, B yang telah diperolehi dari data pengukuran eksperimen. Dalam kajian ini menunjukkan bahawa sifat-sifat kenyal bersandar kepada suhu dan seterusnya memberi maklumat tentang hubungan ikatan fraktal bagi kaca neodimium fosfat yang terletak di antara 2.00 hingga 2.70. Keputusan dari kajian ini menunjukkan bahawa kaca neodimium fosfat mempunyai struktur yang tersusun dalam rangkaian di antara dua dan tiga dimensi.

Kata kunci: sifat kenyal; kaca neodimium fosfat; kajian ultrasonik

The elastic properties of neodymium phosphate xNd2O3(1-x)P2O5 glasses with different compositions containing from 10 to 25 mole % Nd2O3 has been studied by ultrasonic technique, as functions of temperature from 270 K to 303 K. The elastic properties like adiabatic elastic stiffness coefficients, C11, C44 and bulk modulus, B of the glasses have been determined using the experimental data. The temperature dependence of the elastic properties were used to explores useful information about the fractal bond connectivity of the neodymium phosphate glasses which lies between 2.00 and 2.70. This result indicates that the neodymium phosphate glasses were connected in an array between two and three dimensional network.

Key words: elastic properties; neodymium phosphate glasses; ultrasonic studies
Transformasi Polifungsi LUC dalam Sistem Kriptografi
Authors: Yunos Faridah , Mohd Atan Kamel Ariffin , Md Said Mohamad Rushdan
Published: January 2013

Katakan N adalah hasil daripada pendaraban dua nombor perdana berbeza yang besar saiznya iaitu p dan q, N = pq. Teks asal P < N menghasilkan teks saifer C bermodulo N. Katakan (P, N) = 1. Andaikan kunci pengkriptan yang digunakan integer positif e sedemikian hingga (e, N) = 1, penterjemahan P menerusi transformasi Monofungsi LUC ditakrifkan sebagai C ≡ N e (P, 1)(mod N). Pengkriptanan mesej P dikembangkan lagi melalui transformasi polifungsi sehingga menghasilkan mesej saifer. Penyelidikan ini membuktikan bahawa fungsi Lehmer Totient S(N) sentiasa sama pada setiap transformasi bagi membolehkan pelaksanaan penghuraian mesej saifer.

Kata kunci: Teks saifer; Pengkriptanan; Penghuraian

Let N be a product of two large distinct primes p and q, N = pq. The plaintext P < N is encrypted to a cyphertext, C modulo N. Let (P, N) = 1. Assuming that the encrypting key is the positive integer e such that (e, N) = 1, translation of P through the LUC Monofunction transformation is defined by C ≡ N e (P, 1)(mod N). The encrypted message P is extended via polyfunction transformation to produce a cyphertext. We show that the Lehmer Totient function S(N) is always the same in each transformation, enabling us to carry out the decryption process.

Key words: cyphertext; Encryption ; Decryption