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This study aims to analyze the supply chain of potatoes and determine the factors affecting postharvest losses of potatoes at the producer level of Bangladesh. Data were collected through a face-to-face interview schedule from a sample of total 60- 30 farmers, 6 wholesalers, 5 aratdars, 5 retailers, and 14 consumers in Sirajdikhan and Sadar Upazila of Munshiganj district. Descriptive statistics (percentages, frequencies, etc.) and multiple linear regression analysis were used for this study. The result shows that channel 4 is the longest marketing chain in the study area which includes the marketing actors – farmers, aratdars, wholesalers, retailers, and consumers. In the supply chain of potatoes, the amount of postharvest loss is 6.6% for the producer’s level, 5.3% for the wholesale level, 1.10% for the aratdar level, and 2.1% for the retailer level in the study area. The regression model reveals that age and amount of production have a significant positive relationship, while experience has a significant negative relationship with the postharvest losses of potatoes. The study also shows that lack of storage facility (48.94%) and poor packaging system (32.73%) are the major reasons for occurring postharvest losses of potatoes. The farmers and intermediaries suggested that it is necessary to identify the maturity stage of potatoes at harvesting time (70%), improve the cold storage facility (56.67%), and improve the loading and unloading system (56.25%), etc. for reducing postharvest losses of potato.

In this research, the development of digital prepaid energy meters for homes and businesses that use GSM technology is discussed. The reduction of billing cost electricity wastage is the primary goal of prototype development. The GSM module is used to receive short messaging service (SMS) from the user's mobile phone, which automatically enables the controller to take any further action, such as to help the consumer save money by using prepaid energy meter systems offered by power generation and distribution companies. Embedded C is used to integrate the system's microcontroller and GSM network interface. The integration was carried out using Easy EDA software. When the balance on the energy meter falls too low, the system sends the consumer an SMS. Consumer research is then lacking, leaving power without. After getting the SMS command, the Consumer then balances his or her investigation. Therefore, each item facilitates the usage of electrical power in homes and businesses. The prepaid energy meter is then turned ON or OFF by the microcontroller unit, which subsequently automatically controls the electrical power to homes and businesses. In other words, it responds to the message it receives by reading it from the cell phone and controlling the equipment accordingly.

This study was carried out to investigate the factors affecting food security status, patterns of food consumption, and changes in consumption behavior. It also evaluated the gender role in food security and consumption practices in the rural areas of Bangladesh. The research was both in quantitative and qualitative in nature. Qualitative research tools such as FGD, KII and Case Study were used to collect the primary data. Data analysis was done by Microsoft Excel and SPSS. Binary Logistic regression model was used to determine the factors affecting in food security status of the selected households. Regression result shows that income, availability of food and food stock were found to be positive and size of household negatively associated with the food security. Rice dominates the food consumption pattern of the rural people. Income, production, education and awareness are causes of change in consumption behaviour of the people of study area. Men have pivotal role in household food security. Male members involve in income, assure of family assets, and on the contrary female have to manage almost all the unproductive household affairs. In the poorer household women have a little contribution in food security due to male dominating. Women contributions were more than that of men in household food consumption. Most of the household related tasks and household works related to food consumption were done by female.

This study analyzed the gender role in agricultural activities with respect to the change of technologies and determine their implications for improvement of household status in Netrokona district. The study followed the simple random sampling technique to select 300 sample respondents for household survey through the semi-structured questionnaire. Descriptive analysis such as, number and percentages, was used. Multiple regressions used in order to explore the relationship between the income and other factors. Both qualitative and quantitative data analysis techniques were utilized. Women perception index (WPI) was measured using rank ordered approach. The findings showed that there has been significant change occurred with the livestock rearing activities which are 116.79% after adoption in new technology. According to this study, male are involved in decision making in the following activities as reported by the respondents: sale of produce (84%), purchase and repair (78%), weed control (70%), land preparation (76%), spraying (65%) and planting (51%), where women respondents reported that they are mostly involves in harvesting 89%, processing 81%, manuring 48% and weed control 59%. Our research also shows that 78% and 73% of men have owned small equipment and thresher, Ox-plough, and power tiller where women own only 21 percent, 2 percent, and 5 percent respectively. It is evident that the perception regarding farming with adoption of new technology attain highest score and 2nd highest ranked perception is technical training on technology, similarly the 3rd ranked occupied is adoption in HYV where last rank score on use of indigenous technology. It means that most of them prefer modern technology in terms of productivity. The experience on modern technology of respondents has a positive coefficient and it was 0.492. Given these facts, our research has explained what keeps women’s rates of modern agricultural technology adoption low.

This study demonstrates a successful processing and utilization of banana rachis cellulose nanocrystals (CNCs) dispersed clay composite filter which is capable of adsorbing dye and heavy metal ions namely Pb(II) and Cr(III) from industrial wastewater. The composite of different compositions was prepared by dispersing the cellulose nanocrystals, obtained by acid hydrolysis of banana rachis fibres, within the tri-ethyl amine treated clay. The CNC and treated clay were characterized by Fourier transform infrared (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) analyses. Industrial wastewater containing a basic yellow2 dye and two heavy metal ions, Pb(II) and Cr(III), was passed through the prepared filters set in a column. The dye and metal ions adsorption capability of the filters were analyzed by determining the dye and metal ions concentration into the water before and after passing through the composite filter. The concentration of dye and metal ions in water was determined by a UV-visible spectrophotometer and an atomic absorption spectrophotometer, respectively. It was found that the dye adsorption capacity of the composite filters was about 50 mg per gram of composite as well as Pb(II) and Cr(III) ions adsorption capacities of the composite filters were ˃10.0 mg and ˃12.4 mg respectively per gram of the composite when CNC content in the composite was ˃30 wt.%. It was also found that the metal ions adsorption capability of the composite filter was improved with increasing CNC content in the composites.

Chromium (Cr) exists in aqueous solution as trivalent (Cr3+) and hexavalent (Cr6+) forms. Cr3+ is an essential trace element while Cr6+ is a dangerous and carcinogenic element, which is of great concern globally due to its extensive applications in various industrial processes such as textiles, manufacturing of inks, dyes, paints, and pigments, electroplating, stainless steel, leather, tanning, and wood preservation, among others. Cr3+ in wastewater can be transformed into Cr6+ when it enters the environment. Therefore, research on Cr remediation from water has attracted much attention recently. A number of methods such as adsorption, electrochemical treatment, physico-chemical methods, biological removal, and membrane filtration have been devised for efficient Cr removal from water. This review comprehensively demonstrated the Cr removal technologies in the literature to date. The advantages and disadvantages of Cr removal methods were also described. Future research directions are suggested and provide the application of adsorbents for Cr removal from waters.

Understanding the evolutionary and genetic underpinnings of susceptibility to pathogens is of fundamental importance across a wide swathe of biology. Much theoretical and empirical effort has focused on genetic variants of large effect, but pathogen susceptibility often appears to be a polygenic complex trait. Here we investigate the quantitative genetics of survival over 120 hours of exposure (“susceptibility”) of C. elegans to three bacterial pathogens of varying virulence, along with the non-pathogenic OP50 strain of E. coli. We compare the genetic (co)variance input by spontaneous mutations accumulated under minimal selection to the standing genetic (co)variance in a set of ∼50 wild isolates. Three conclusions emerge. First, with one exception, mutations increase susceptibility to pathogens, and susceptibility is uncorrelated with fitness in the absence of pathogens. Second, the orientation in trait space of the heritable (co)variance of wild isolates is sufficiently explained by mutation. However, pathogen susceptibility is clearly under purifying, apparently directional, selection of magnitude similar to that of competitive fitness in the MA conditions. The results provide no evidence for fitness tradeoffs between pathogen susceptibility and fitness in the absence of pathogens, nor that balancing selection is important in maintaining genetic variation for susceptibility to these bacterial pathogens.

Bilevel optimization problems involve a hierarchical model where an upper level optimization problem is solved with a constraint on the optimality of a nested lower level problem. The use of evolutionary algorithms (EAs) and other metaheuristics has been gaining attention to solve bilevel problems, especially when they contain non-linear/black-box objective(s) and/or constraint(s). However, EAs typically operate in a nested mode wherein a lower level optimization is executed for each upper level solution. Evidently, this process requires excessive number of function evaluations, which might become untenable if the underlying functions are computationally expensive. In order to reduce this expense, the use of approximations (also referred to as surrogates or meta-models) has been suggested previously. However, the previous works have focused only on the use of surrogates for the lower level problem, whereas the computational expense of the upper level problem has not been considered. In this paper, we aim to make two contributions to address this research gap. The first is to introduce an improved nested EA which uses surrogate-assisted search at both levels in order to solve bilevel problems using limited number of function evaluations. The second is the revelation and a systematic investigation of a previously overlooked aspect of bilevel search – that the objective/constraints at the upper and lower levels may involve different computational expense. Consideration of this aspect can help in deciding a suitable strategy, i.e., in which level is the use of surrogates most appropriate for the given problem. Towards this end, four different nested strategies – with surrogate at either level, none or at both levels, are compared under various experimental settings. Numerical experiments are presented on a wide range of problems to demonstrate the efficacy and utility of the proposed contributions.

Device-to-device (D2D) communication is such a paradigm that anticipated to play a cabalistic role for the next-generation cellular networks especially for the 5G cellular network as it promises to extend the network coverage and offload some traffics from the cellular transceiver’s side to the user devices’ side and it may operate in both licensed and unlicensed spectra simultaneously. D2D communication in the unlicensed spectrum may facilitate the purpose of D2D communication as the licensed spectrum almost possessed. Interference is the main drawback of the unlicensed spectrum. In this paper, we propose the request-to-send/clear-to-send (RTS/CTS) mechanism with the free-to-receive (FTR)-MNAV technique to improve the performance of the D2D communication in the unlicensed spectrum. Deployment of the carrier sense multiple access with collision avoidance (CSMA/CA) protocol can alleviate interference, but collisions occur due to the hidden node problem. The integration of the RTS/CTS mechanism with the CSMA/CA protocol can minimize the hidden node problem, but the blocking and false blocking problems are introduced. The proposed scheme can reduce the blocking and false blocking problems, which improves the performance of the D2D communication in the unlicensed spectrum where neighbor nodes maintain Multiple Network Allocation Vector (MNAV) to resolve the blocking problem and broadcast the FTR control packet to the respective neighbor nodes if the transmission is completed prior to the expiration of the timer or actual communication does not take place due to any reason, thus solving the false blocking problem and improving the performance of the D2D communication in the unlicensed spectrum.

In this paper, the performance of the Device-to-device (D2D) communication in the unlicensed spectrum has improved by integrating the Compressive Sensing (CS) algorithm and Ready-To-Receive (RTR) control packet along with the RTS/CTS mechanism. Blocking and false blocking problems are introduced among the neighbor nodes due to the implementation of the RTS/CTS mechanism to overcome the hidden node problem which arises for the deployment of the CSMA/CA protocol to mitigate the interference of D2D communication in the unlicensed spectrum. CS can compress the data thus reduce the needed bandwidth to transmit throughout the channel which significantly reduces the transmission time. RTR control packet broadcast to the respective neighbor nodes if the existing communication is completed prior to the expiration of the timer which reduces the blocking and false blocking problems.

Device-to-device (D2D) communication is such a paradigm that appears to be a sustainable alleviation for the existing cellular network as the existing network struggling to accommodate the excessive amount of data demand for the cellular users due to the scarcity of the wireless resources. Security threats are the critical impediment to achieve the purpose of the D2D communication as attackers may easily intercept the wireless communication link due to the vulnerable attribute of the wireless communication channel and its broadcasting nature which degrades the performance of the D2D communication. The highest possible security steps need to take into account to upgrade the performance of the D2D communication. In D2D communication, the network layer is the vital layer as data routing and transmission are performed throughout this layer and attackers constantly attempts to affect the transmitted data through this layer. In this paper, we propose three ways secure handshaking mechanism to emphasize the security of the D2D communication by ensuring the secure transmission channel between two users, authenticating the users and encrypting the transmitted data. Thus, the propose handshaking mechanism minimizes security threats and maximizes the performance of D2D communication.

Mungbean is an important indigenous vegetable legume providing protein for the rural and urban poor in South and Southeast Asia. This study was conducted to analyze the value chain, determine the value addition at different levels of value chain of mungbean and identify some constraints of mungbean marketing in Bangladesh. Using a structured questionnaire with face to face interviews, 120 samples were surveyed which were collected from Barisal and Patuakhali district of Bangladesh during the period of 2017-18. The stratified random sampling technique was used in selecting the sample. This study found that the main actors of mungbean marketing were farmer, arathder, wholesaler, retailer and consumer. The study also revealed that mungbean production was found profitable. The study revealed that the cost of mungbean production of a farmer was Tk 40955/ha on full cost basis and Tk. 28055/ha on cash cost basis. The average gross return of a farmer was Tk. 49775/ha and gross margin was found Tk. 8820/ha on full cost basis and Tk. 21720/ha on cash cost basis. Value addition of arathder and wholesaler was Tk 80/maund and Tk 190/maund respectively and value addition of retailer was Tk 410/maund. In the study area farmers and traders mentioned some problems at production and marketing level such as shortage of capital, lack of labour, insecticides, severe attack of insects, dominance of intermediaries, lack of adequate market facility etc. So, government should take proper initiative to solve these problems. [J Bangladesh Agril Univ 2021; 19(4.000): 521-527]

Chromium (Cr), Lead (Pb) and Cadmium (Cd) have been conceded as one of the most perilous heavy metals which causes a prominent affliction on both environment and human health. In this study, chemical modification of biodegradable, eco-friendly materials such as cellulose and chitosan were carried out to prepare a composite adsorbent and established an optimized condition for adsorption of heavy metal ions such as Cr, Pb and Cd from contaminated aqueous wastes. α-cellulose was treated with HCl and H2SO4 to have better adsorption properties. On the contrary, modification of chitosan was carried out by acetaldehyde solution and acetic acid. Composite adsorbent was obtained as a mixture, comprising of modified cellulose and chitosan in a specific proportion (2g:1g). The surface characteristics of treated cellulose, chitosan and composite sample were evaluated by FTIR and SEM analysis. In addition, batch adsorption experiments were carried out to measure the influences of pH of the solution, adsorbent dosage and the initial concentration of metal ions. The maximum removal efficiency of Cr, Pb and Cd by composites was 56, 85 and 94%, respectively, at pH 4 when the metal concentration and adsorbent dosage were 60 ​ppm and 1.0 ​g ​L−1. The maximum adsorption of Cr, Pb and Cd by composites was 55, 80 and 91 ​mg ​g−1, respectively, at pH 4 when the metal concentration and adsorbent dosage were 120 ​ppm and 1.0 ​g ​L−1.

Bangladesh Journal of Medicine, Vol 23 No 2, 2012, Page 62-66 DOI: http://dx.doi.org/10.3329/bjmed.v23i2.14986

Bilevel optimization involves searching for the optimum of an upper level problem subject to optimality of a nested lower level problem. These are also referred to as the leader and follower problems, since the lower level problem is formulated based on the decision variables at the upper level. Most evolutionary algorithms designed to deal with such problems operate in a nested mode, which makes them computationally prohibitive in terms of the number of function evaluations. In the classical literature, one of the common ways of solving the problem has been to re-formulate it as a single-level problem using optimality measures (such as Karush-Kuhn-Tucker conditions) for lower level problem as complementary constraint(s). However, the mathematical properties such as linearity/convexity limits their application to more complex or black-box functions. In this study, we explore a non-nested strategy in the context of evolutionary algorithm. The constraints of the upper and lower level problems are considered together at a single-level while optimizing the upper level objective function. An additional constraint is formulated based on local exploration around the lower level decision vector, which reflects an estimate of its optimality. The approach is further enhanced through the use of periodic local search and selective “re-evaluation” of promising solutions. The proposed approach is implemented in a commonly used evolutionary algorithm framework and empirical results are shown for the SMD suite of test problems. A comparison is done with other established algorithms in the field such as BLEAQ, NBLEA, and BLMA to demonstrate the potential of the proposed approach.

Bilevel optimization, as the name reflects, deals with optimization at two interconnected hierarchical levels. The aim is to identify the optimum of an upper-level leader problem, subject to the optimality of a lower-level follower problem. Several problems from the domain of engineering, logistics, economics, and transportation have an inherent nested structure which requires them to be modeled as bilevel optimization problems. Increasing size and complexity of such problems has prompted active theoretical and practical interest in the design of efficient algorithms for bilevel optimization. Given the nested nature of bilevel problems, the computational effort (number of function evaluations) required to solve them is often quite high. In this article, we explore the use of a Memetic Algorithm (MA) to solve bilevel optimization problems. While MAs have been quite successful in solving single-level optimization problems, there have been relatively few studies exploring their potential for solving bilevel optimization problems. MAs essentially attempt to combine advantages of global and local search strategies to identify optimum solutions with low computational cost (function evaluations). The approach introduced in this article is a nested Bilevel Memetic Algorithm (BLMA). At both upper and lower levels, either a global or a local search method is used during different phases of the search. The performance of BLMA is presented on twenty-five standard test problems and two real-life applications. The results are compared with other established algorithms to demonstrate the efficacy of the proposed approach.

In recent years, spectrum scarcity is a major problem in wireless communication system which has been brought to a solution by using cognitive radio technology. This technology tends to increase the spectrum utilization. In this paper, an energy detection method has been proposed for proper utilization and allocation to the spectrum and also an overview of spectrum in Bangladesh. In real time system energy detection can be broadly used as a signal detection method for its lower complexity characteristics. Our scheme helps any channel distributor, by measuring the quantity of bandwidth that can be provided at any given time to any unlicensed user. From result we found that the output could be beneficial for the improvement of spectrum scarcity problem, save money and can develop our communication network system.

The performance of turbo-codes relies on two major concepts: code concatenation so as to build a powerful global code and iterative decoding in order to efficiently approximate the optimal decoding process. A turbo equalization (TE) scheme based on convolutional code and normalized least mean square equalizer for coherent optical communication links is proposed and experimentally demonstrated. For counteracting PDM 16 QAM impairments in dispersion uncompensated coherent transmission links, the iterative TE technique is proved effective.

Ultra wideband (UWB) radio technology is becoming very popular for certain short range applications including indoor communications systems, home networks, cordless phones, high speed local area networks, and security sensors in wireless communications. Due to reducing link lengths and higher data rate, the UWB systems need sophisticated propagation models and more precise characterization of the radio channel. In particular, the planning of the coverage in indoor spaces creates design problems without deterministic models. In this paper, the finite difference time domain (FDTD) method is used for time domain electromagnetic modeling of ultra wideband indoor radio channel and prediction of wave propagation through indoor channel. The accuracy of the simulated results for predicting the performance of indoor UWB communication systems is assessed by comparison with the corresponding measured result.

The point view of the research offers regulating the road and transportation system of Bangladesh digitally. According to BRTA's annual accident report of five years, it can be said that speed breakers have a great impact on the road accidents. The road authority tries to control the accidental facts by placing speed breakers on the road. This paper offers RFID based virtual speed breaker instead of the traditional speed breaker. That will decrease the construction cost as well as vehicle maintenance cost. It is a smart vehicle controlling system that will ensure the safety of the passengers whither the driver is conscious or not.

In this paper, an attempt has been made to investigate the impact of free space transfer function taking into effects of atmospheric turbulence, pointing errors and path loss factor on the performance of free space optical communication system. The performance of the proposed free space optical communication system is studied by developing a MATLAB simulator using simulink in which free space is used as a communication channel. Finally, we evaluated the Bit Error Rate (BER) performance of the proposed system varying with different system parameters such as distance, transmitter power, path loss factor, atmospheric turbulence and received signal power. The BER is highly degraded on severe atmospheric turbulence condition ever for a short distance of free space channel. The effect of path loss factor due to dense fog is also severe on the BER even though the turbulence effect and free space distance is short. The optimum transmitted input power and receiver antenna radius at which the BER is minimum, is strongly dependent on free space distance and atmospheric parameters.

OpenStreetMap (OSM) is a world-wide campaign for developing open source maps. The prospect of such open source maps is very bright in commercial, educational and political points of views. With the burgeoning growth of mobile phones, the necessity of location based services is increasing day by day. Starting from the 3G mobile applications to cheap SMS-based services, we need maps everywhere. Various applications of digital maps are also seen in different national and international issues. Hence, OSM has been growing at a rapid pace in different parts of the world. However, it is a bit challenging task to develop this sort of voluntary efforts in the developing third world countries, like Bangladesh. In this paper, we discuss the possible fields of disaster responses in Bangladesh where OSM can play a vital role. We also discuss about the problems we face while developing OSM for this region. Finally, we talk about a number of ways which can be instrumental while trying to make free open source maps avoiding all the difficulties.

Automated Essay Grading (AEG) is a very important research area in educational technology. Latent Semantic Analysis (LSA) is an Information Retrieval (IR) technique used for automated essay grading. LSA forms a word by document matrix and then the matrix is decomposed using Singular Value Decomposition (SVD) technique. Existing AEG systems based on LSA cannot achieve higher level of performance to be a replica of human grader. We have developed an AEG system using Generalized Latent Semantic Analysis (GLSA) which makes n-gram by document matrix instead of word by document matrix. The system has been evaluated using details representation. Experimental results show that the proposed AEG system achieves higher level of accuracy as compared to human grader.