Browsing by Author "Saiful Islam, Md."

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Analysis and compensation of PMD effects in high speed fiber-optic transmission systems using different modulation and detection scehemes
(Department of Electrical and Electronic Engineering, BUET, 2008-05-27) Saiful Islam, Md.; Majumder, Dr. Satya Prasad
Polarization Mode Dispersion (PMD) is a serious barrier that limits high-speed optical fiber telecommunication systenls. PMD is the result of random birefringence in single-mode fibers along the transmission path. This leads to wavelength-dependent polarization states and phases at the output that eventually results in inter-symbol interference and system performance degradation. In this thesis work, analytical models have been developed to assess and compensate for the effect of PMD considering different modulation and detection schemes; such as, intensity modulation-direct detection (lM-DD), continuous phase frequency shift keying (CPFSK) directand heterodyne detection. Based on the analytical model, the average BER performance of an IMDD optical transmission system is evaluated considering Maxwellian distribution for the differential group delay (DOD). The probability density functions (pdfs) of the random output signal phase fluctuation due to PMD in a CPFSK direct- and heterodyne detection system are analytically developed. The pdf of the signal phase fluctuation is used to evaluate the average BER as a function of mean DOD. As the passive PMD mitigation techniques do not require any dynamically adjusted components, and are bit rate independent, an analytical model of PMD compensation technique is also developed with several Iinecoding to make the single channel optical transmission system more tolerant to PMD. The impact and compensation of PMD in multi-channel optical transmission system is also analytically investigated considering the interaction of cross-phase modulation (XPM) and PMD. XPM changes the state-of-polarization (SOP) of the channels through nonlinear polarization rotation and induces nonlinear time dependent phase shift' for polarization components that leads to amplitude modulation of the propagating waves in a wavelength division multiplexing (WDM) system. The angle between the SOP changes randomly and as a result PMD causes XPM modulation amplitude fluctuation random in the perturbed channel. The pdf of the random angle fluctuation between the SOP of pump and probe due to PMD is determined analytically and the impact of PMD on XPM in a two channel pump-probe configuration is evaluated. To mitigate the PMD in a multi-channel transmission system, a high-birefringent adjustable linear chirped Bragg grating (LCFBO) based PMD compensation scheme is developed and its performance is evaluated using the optimum system parameters. The results of this research work will find applications iri the design of WDM transmission systems in presence of fiber nonlinear effects and PMD.
Assessment of the potential for arsenic accumulation in rice field soils in Bangladesh and its implication on rice yield
(Department of Civil Engineering, 2012-08) Saiful Islam, Md.; Ali, Dr. M. Ashraf
Widespread use of arsenic (As) contaminated water for irrigation to produce dry season crop (mainly boro rice) poses threats to sustainable agriculture and to human health in Bangladesh. Presence of As in irrigation water leads to elevated levels of As in soil, with significant spatial and temporal variation. Monsoon flooding removes significant fraction of As added to soil through irrigation each year. Reported soil-As data from non-flooded areas show much higher retention of As added through irrigation water. So areas without pronounced monsoon flooding are at greater risk of soil-As accumulation than seasonally flooded paddy fields. This study makes an assessment of the potential of arsenic accumulation through irrigation in soil where extensive boro rice cultivation is carried out; the potential of arsenic accumulation has been presented in the form of a “Arsenic Hazard Map”. The Arsenic hazard map has been prepared considering the hypothesis on As deposition/ mobilization in paddy soils, using data on arsenic distribution in groundwater, boro cultivation/ irrigation intensity, and flood inundation depth. This risk level of arsenic accumulation in soils has been divided into seven categories: (a) Very high-risk area, (b) High-risk area, (c) Moderate-risk area, (d) Moderate to low-risk area, (e) Low-risk area, and (f) Very low-risk area. According to the Arsenic Hazard Map, areas to the south-west and some areas in the north-east are at risk of higher accumulation of arsenic, because of higher concentration of arsenic in irrigation water, higher intensity of boro cultivation, and higher land elevation. “Query analysis” of the hazard map reveals that 282,267 ha of highland used for boro cultivation in 22 upazilas of the south-western region of Bangladesh are at “very high risk” of arsenic accumulation, because of higher arsenic in STW irrigation water and low flood inundation depth; and 382,001 ha of highland in 35 upazilas are at “high-risk” status, where flood inundation depth is low , but arsenic concentration in STW irrigation water is also relatively low. Areas in the northern parts of Bangladesh are at “low to no risk” because of lower concentration of arsenic in irrigation water, despite higher intensity of boro cultivation. Some areas in the south-central region of Bangladesh are at “moderate to low risk” of arsenic accumulation because of higher elevation of these areas (which results in lower flooding intensity). Soil-As data from primary (i.e., field sampling and analysis) and secondary sources qualitatively validate the Arsenic Hazard Map prepared in this study. Soil-As map prepared form collected primary and secondary data shows that in most of the south western region, soil-As level exceed 30 mg/kg. An assessment of the impact of arsenic accumulation in soil on rice yields in selected high-risk areas has been made utilizing available data/ information correlating arsenic in irrigation water and agricultural soil, and soil arsenic and crop yield. It appears that significant rice yield reductions could result in the future due to accumulation of arsenic in irrigated soil. Estimated yield reductions in nine high-risk upazilas varied for about 9 percent to 24 percent for the year 2020, and 12 percent to 53 percent for the year 2050. Possible yield reduction due to elevated soil arsenic appears to be a potential threat to food security and agricultural sustainability in Bangladesh, where rice is the main crop and staple food, and boro rice accounts for over 50 percent of total rice productions.
Automatic facial expression recognition scheme based on differential feature extracted from dynamic regions
(Department of Electrical and Electronic Engineering (EEE), BUET, 2019-03-24) Saiful Islam, Md.; Anowarul Fattah, Dr. Shaikh
Generally human beings reveals various types of emotions through different facial expressions. However even for a same person, depending on the surrounding environments, a same type of emotion can be exhibited by various facial expressions. Obviously for different persons, variation in facial expression is expected to be much higher for a same emotion. Hence automatic emotion recognition from a given facial expression is a very challenging task. In order to convey an emotion, different regions of a face may exhibit changes in pattern with respect to the neutral face (no emotion). These changes are sometimes very prominent and can easily be recognized by naked eye but in many cases, they are not clearly noticeable and changes occur in pixel level information. In the proposed schemes, first various dynamic regions of a face are identified, where significant changes are expected during emotion elicitation with respect to other parts of the facial image. Next each pixel in that dynamic region is taken into consideration to form a feature vector from the given facial image. Since entropy is a measure of information content in a process, in order to capture information about pixel intensity variation due to change in facial expression in a region, entropy function is proposed as feature. The main idea here is to capture the variation in intensity distribution along the vertical direction of an image, for example which can be an entropy values extracted from various overlapping rows of pixels. Apart from entropy, different statistical measures are also investigated as features. Moreover, similar feature extraction process is also tested on transformed images, considering Fourier transform, Discrete Cosine transform, Wavelet transform and Hilbert transform. Finally considering the ease of computation binary level logical operations, such as logical AND, OR, XOR between the pixels are also performed to extract the feature vector. One advantage of the proposed method is the generation of 1D feature vector from the 2D facial image. As a result a differential 1D feature vector with respect to neutral face feature is computed, which is expected to contain better discriminative characteristics for different emotions. Moreover, a simple sliding technique is presented that operates on proposed 1D feature to obtain vertical and horizontal shift invariance recognition system. For the purpose of classification distance based classifier is used and two widely used challenging facial emotion databases JAFFE and CK+ are tested. The proposed method offers very satisfactory recognition performance with respect to person, pose, illumination and shift variation.
Performance of existing pond sand filters and design modification
(Department of Civil Engineering, 2002-08) Saiful Islam, Md.; Mujibur Rahman, Dr. Md.
Pond'Sand Filter (PSF), a simple option has been used mainly in the southern fringes of Khulna, Bagerhat, Satkhira, Jhalokathi, Noakhali, Perojpur and Barguna districts to treat the water from rain-fed ponds where ground water is mostly saline and suitable freshwater aquifers are not available. However, recent reports have shown that the performance of the existing PSFs are not satisfactory. Out of 477 PSFs in Pathorghata Upazila, Barguna only 36 (i.e. about 8%) are working (DPHE-Danida, 2000). In this study the performance of the existing PSFs in Pathorghata and Mathbaria Upazila were investigated. The major problems of the existing PSFs include slow production, poor performance in removing fecal coliform, shorter filter run and poor operation and maintenance. This study also reveals that performance of PSFs are declining due to some design faults including insufficient depth of filter bed, inadequate pre-filter chamber, insufficient outlet structure to prevent the negative pressure in the filter bed, lack of awareness among the beneficiaries. A survey was carried out among the beneficiaries about their opinion towards the existing PSFs and their participation in operation & maintenance. After critical examination of the technical, social and water quality issues of the existing PSFs, a modified community type PSF was developed on a pilot basis. Design modifications were made by providing sufficient depth of filter bed and incorporating a horizontal flow-roughing filter following vertical up-flow roughing filter with intermediate buffer zone. These were done as a method of extending runtime before cleaning by reducing raw water turbidity for trouble free operation of sand filter bed and effective capture of Fecal Coliform. The community type pilot PSF was constructed at Dhanisafa Munshi Bari, Mothbaria Upazila under Perojpur District. Another household type model PSF was also developed which was installed in the Concrete Laboratory of BUET. The study also examined the effectiveness of various treatment units of the community type pilot PSF and household type model PSF and, the findings were analyzed. Some important parameters including total coliform, fecal coliform, turbidity, salinity, pH, color, COD, TS, TDS, SS and arsenic were tested for the raw water and treated water at vmious steps of treatment process. Extensive laboratory investigations were done to determine the effectiveness of the treatment units of the community PSF and household type model PSF. Removal of bacteria particularly Fecal Coliform and time interval of washing the filter bed were also analyzed based on observational and experimental findings. In combination with roughing filters, the average turbidity and faecal coliform removal efficiency of sand filters were found to be 93.97% and 99.93% respectively. Filter run of the modified model PSF has also increased from about 30 days (in case of existing PSF) to 128 days. Performance assessment of the community type pilot PSF and household type model PSF were done in terms of quality of filtered water, ease of operation & maintenance, monthly check up of production capacity/efficiency of filter, observation of people's participation and acceptability of the modified PSF.
Quantification of the effect of road geometry and environment on vehicle speed
(Department of Civil Engineering, 1996-08) Saiful Islam, Md.; Shamsul Hoque, Dr. Md.
Characteristics of drivers and vehicles, elements of road geometry and environmental conditions are the major factors affecting vehicles speed. The first two items can be identified but are difficult to be quantified. Road geometry and environmental conditions are apt to be both identified and quantified. In this study six important factors which have significant influence on vehicles speeds, such as road deterioration, curvature, presence of motorized and non-motorized vehicles in the traffic stream as well as environmental conditions such as dry/wet pavement conditions, visibility etc. have been identified for investigation. The main objectives of this study was to quantify the effect of these factors on vehicles speeds and to identify the factors which affect vehicles speed most. In order to quantify the effect of a particular factor on speeds, comparative studies use carried out between speeds in ideal road conditions and that of road with the infl uence of the particular factor being studied. Spot speeds data were collected manually from nine roads links in Dhaka city road network. Computer program EXCEL has been used for comprehensive statistical analysis viz. mean speed, speed range, standard deviation, maximum and minimum speeds values etc. for each type of vehicle categories. ORIGIN software has been used for producing bar chart to show the effects of selected variables on vehicles speeds. This research has revealed that at free flow condition in urban area width of road has significant effect on free speed of passenger cars and for this type of vehicle the maximum reduction of speed was observed to be around 30% when speeds were compared between twelve and four lane road. The effect of road width on the mean speed of cycle was found to be a minimum reduction of nearly 7.7%. From four lanes road to six lanes road the mean stream speed of motorized vehicles is increased only by 3.6 km/hr in built-up area and for twelve lanes this value is increased by 16 kmlhr. Medium rainy condition was found to affect considerably the mean speed of micro buses, utilities, mini buses, auto rickshaws and motor cycles. The reduction were of the order of 44.4%, 39.8%, 34.3%, 24.2% and 44.4% respectively. Rainy condition decreased the mean stream speed for motorized of vehicles by 29.5%. The result of this research has shown that particular deterioration has maximum effect on the mean speeds of large bus and bi-cycle with speed reduction of 35.4% and 21.7% respectively. Deterioration of road decreases the motorized stream speed by 28.6%. At free flow condition the effect of Non-Motorized Vehicles (NMV) is found to have the minimum effect on the mean speeds of passenger cars, util ity vehicles, mini buses, large buses, auto rickshaw and motor cycles. The minimum effect on the mean speed of micro bus is found from the radius of curve at 145 ft and its mean speed is decreased by 4.4%. For other types of vehicles, due to the effect of curvature mean speeds were decreased by 5% to 20%. The effect of curvature on motorized stream speed is very low. Results indicate that the mean speed of motorized vehicles at night time decreased by 10%-25% of day time speed values except for auto rickshaw. One interesting finding was cycle rickshaw speeds showed slight increases at night time. This condition may be due to the fact that, rickshaw pullers feel more comfortable 10 pull rickshaws at cooler temperature than the hot sunny day when they get tried very quickly. At night the mean stream speed of motorized traffic is decreased by 6 to 7 kmlhr and non-motorized stream speed is increased by 2 kmlhr. It is also revealed that at free flow condition mean speeds of the loaded rickshaws are slightly greater than those of the unloaded rickshaws. From the analyses of mean speeds, standard deviations and speed ranges it was revealed that by and large the mean free speeds of auto rickshaws and trucks were not affected significantly by road geometries and environmental conditions except highly deterioration effect for Auto rickshaws. The mean speed of auto rickshaw decreased about 20% on highly deteriorated roads and for other conditions, auto rickshaws were found that it run at their maximum speed levels and were found to be changing less sensitive to roadway conditions.
Report on industrial attachment at Rupashi Knit Wears Ltd. Lamapara, Kutubpur, Fatullah, Narayanganj
(Daffodil International University, 2014-11-03) Saiful Islam, Md.; Alauddin, G.M.; Zabed Chowdhury, Mohd.
The Industrial Attachment is the most effective way for Textile Engineering student to be achieved the knowledge about the practical field of the Textile Manufacturing. It brings an opportunity to all the learners to enrich their academic knowledge by practicing with the experts of the practical field of textile. The internationally recognized buyers or clients are looking for those countries for producing their apparel products where different types of industries have established as a one stop source for the global apparel market, satisfy and meet customer’s expectation by developing and providing product and services on time which offer value in terms of Quality, Low price, Safety & Environmental Impact. And also assure complete compliance with the international quality standard and also provide the employees internationally acceptable working condition Bangladesh. There are varies group of Textile Industries those are producing high quality textile & apparel products. Rupashi Group is one of them. Rupashi Group has a number of sister concerns in the family. Those are Rupashi Embo World, Rupashi Design & Printing, Rupashi Fabric Complex (pvt.) Ltd, Shoeb Packaging (Bd), Sadia Knit Composite, Shoeb Knit composite. Rupashi Group is one of the biggest knit garments manufacturers & exporters. The have different types of knitting, dyeing, printing, cutting, sewing, finishing & washing process. All the machines, equipments & chemicals used in different process are well branded. They produce various types of knit products for their buyer those are coming from various countries such as North America, South America, Western Europe, Eastern Europe, Eastern Asia, Southeast Asia, Mid East, Africa. They follow all th system for their machines maintenance so production can not hamper. In this report we have tried to give some information about Rupashi Knit Wears Ltd and we observed that they are produce high quality Garments and fulfill the requirements of buyers by following various internationally recognized method. So we are highly pleasure for that we had an opportunity to complete our two month internship at Rupashi Knit wears Ltd. , which is one of the most modern industries of the country.