Performance Analysis of CDMA System Using Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum Techniques

In digital communication system, selection of the most appropriate access method is a challenging task. To meet this challenge we have to be familiar with the technologies and system architectures on the CDMA digital cellular system. The demand for high speed mobile wireless communications is rapidly growing. DS-CDMA plays the best competitive role for achieving the high data capacity and spectral efficiency requirements for communication systems. This paper represents the performance analysis of CDMA using direct sequence and frequency hopping technique in a Fadin

Development of a Microarray Biosensor for Real-Time and Continuous Measurement of Neurochemicals

Continuous simultaneous measurement of glutamate (GLU), an excitatory neurochemical, and γ-aminobutyric acid (GABA), an inhibitory neurochemical, constitutes one of the major challenges in neuroscientific research. Maintaining appropriate levels of GLU and GABA is important for normal brain functions. Abnormal levels of GLU and GABA are responsible for various brain dysfunctions, like epilepsy and traumatic brain injury. GLU and GABA being non-electroactive are challenging to detect in real-time. To date, GABA is detected mainly via microdialysis with a high performance liquid chromatography (HPLC) system that employs electrochemical (EC) and spectroscopic methodologies. However, these systems are bulky and unsuitable for real-time continuous monitoring. As opposed to microdialysis, biosensors are easy to miniaturize and are highly suitable for in-vivo studies. Unfortunately, this method requires a rather cumbersome process that relies on externally applied pre-reactors and reagents. Here, we report the design and implementation of a GABA microarray probe that operates on a newly conceived principle. It consists of two microbiosensors, one for GLU and one for GABA detection, modified with glutamate oxidase and GABASE enzymes, respectively. The detection of GABA by this probe is based upon the in-situ generation of α-ketoglutarate from the GLU oxidation that takes place at both microbiosensor sites. By simultaneously measuring and subtracting the H2O2 oxidation currents of GLU microbiosensor from GABA microbiosensor, GABA and GLU can be detected continuously in real-time in vitro and ex vivo. This mechanism happens without the addition of any externally applied reagents. We optimized our novel approach in commercially available ceramic-based probes. The GABA probe was successfully tested in an adult rat brain slice preparation. However, those electrodes are geometrically limited (we cannot have a sentinel site at the same spatial level as GLU and GABA sites). Keeping theseissues in mind, we have developed a microwire array sensor that is not only capable of simultaneous measurement of GLU and GABA, but is also able to track signal resulting from interferents (e.g. Ascorbic Acid, AA). The unique geometry enables these microwire probes to measure GLU, GABA and interferents in the same spatial level. A Simple fabrication procedure and easy integration with the existing amperometric systems allow us to use them in cell culture, brain tissue, and in vivo recordings as an inexpensive alternative to our planar electrodes. We demonstrated the effectiveness of the probes in rat brain tissue. We were able to get. Additionally, we determined the excitation/inhibition (E/I) ratios for different stimulations which have clinical relevance. Our results about this E/I balance can help refine electrical stimulation parameter for different clinical purposes (e.g. deep brain stimulation). Finally, we successfully tested our probe in awake-free behaving rats. In summary, our results suggest that microwire probes have the potential to become a powerful tool for measuring GLU and GABA in various ex-vivo and in-vivo disease models, such as epilepsy

Evaluation of Undrained Shear Strength and Soil Classification from Cone Penetration Test

The in-situ cone and piezocone penetration tests (CPT, PCPT) has been widely used by the geotechnical engineering community for subsurface soil characterization and classification, and for the evaluation of many engineering soil properties, such as undrained shear strength (su), unit weight (γ), constrained modulus (M), coefficient of consolidation (cv), and stress history (OCR). The objective of this research study was to estimate the undrained shear strength of clayey soil using CPT/PCPT data in addition to some soil boring log data. At the same time, soil classification charts/methods based on CPT/PCPT were investigated and modified. For this purpose, 70 cone penetration test data collected from 14 different parishes in Louisiana were analyzed. In each site, both laboratory and CPT tests were performed at the same location in order to evaluate the soil parameters (e.g., corrected cone tip resistance, qt; sleeve friction, fs; total overburden pressure, σvo; plasticity index, Ip; Liquid limit, LL; and moisture content, MC). Both linear and non-linear statistical regression models were developed and verified using the measured soil parameters to estimate su of clayey soil for individual soil layers. The su model that contains qt, fs, and σv0 parameters is found to be the best model that satisfies all the statistical parameters, and that the estimated values of su are close to the measured values. In addition, three basic soil zones (e.g., sandy, silty and clayey) have been modified in some CPT/PCPT based soil classification charts. The CPT/PCPT soil classification charts investigated in this study include Douglas and Olsen (1981) chart, modified Schmertmann chart by Tumay (1985), Robertson (1990, 2009 and 2010) charts, Saye et al. (2017) chart, and Zhang and Tumay (1999) probability method. Among these charts, the Robertson (2010) chart showed better prediction to categorize soils for Louisiana. In addition, the Zhang and Tumay (1999) probability method is found to be suitable to categorize the sandy and clayey soil type behavior, but was not so clear for the silty soil behavior

Bangla character recognition system is developed by using automatic feature extraction and XOR operation

This paper presents off-line bangle character recognition system using automatic feature extraction and XOR operation. In this system, the Bangla text is accepted as an image file which is first segmented into lines and words and then each word is segmented into characters. The pixels outside the boundary of the character are eliminated. The characters are scaled to a size equal to the database image. A XOR operation is performed between the scaled image and the database image and the error (%) is calculated. Finally, depending on the minimum error, the system recognizes the character to use in the output. The average recognition accuracy rate of the system was about 80%

Patterns of Informality in the Ship Breaking Industry of Bangladesh

The relationship between economic growth and formalization of industrial sectors has not been unidimensional as several studies have brought different aspects of it from diverse contexts. This paper tries to evaluate the persistence of informality in the ship breaking industry of Bangladesh by setting it against the proclaimed formality of the sector. In addition, the paper also seeks to support the argument that informal patterns of employment can persist, if not grow, within a formal system. Both qualitative and quantitative data have been collected by questionnaire survey and key informant interviews. Analysis of the findings reveal a strong presence of informality within labor market dynamics of ship breaking industry in Bangladesh while several administrative aspects of the industry remain formalized. Study findings support the notion that growth as well as institutional development cannot necessarily transform informal conditions of labor market in developing country context

Factors influencing consumers’ attitude towards online shopping in Rangpur City

Nowadays Bangladesh is called a “DIGITAL BANGLADESH”. The propensity of online shopping and businesses is increasing these days. The digital environment spreads out not only in the country but also in Rangpur City. Over the last few years, online shopping has improved and the number of people who have access to the web has increased. A positive attitude towards online shopping and selling is being observed in Bangladesh. The young generation is much more involved in space marketing or shopping than in a place. The main aim of this research is to investigate the consumers’ attitudes toward online shopping and the factors influencing consumers towards online shopping. To meet the study objectives a quantitative survey method was employed. Researchers select 150 respondents by the technique of non-probability convenience sampling. The questionnaire of the study was developed from the previous literature. The research result shows that 60% of the respondents are male, and the rest are female between the 16-59 age groups, with a Secondary school certificate to postgraduate educational level. Most of them spend 2-4 hours on the Internet daily. The result also revealed that convenience, time-saving, website design, perceived enjoyment, and people engagement and their review rating have a significant positive relationship with consumer attitudes toward online shopping

Examining citizens’ trust in local government institutions: a focus on upazila parishads (sub-district councils) in Bangladesh

Against a backdrop of strikingly limited research on the subject, this article examines citizens’ trust in upazila parishads (UzPs) – a historically significant form of local government institution (LGI) in Bangladesh. A set of indicators has been developed that help to evaluate citizens’ trust in these LGIs. Alongside secondary literature and official document reviews, a mixed-method approach was adopted for empirical data collection combining quantitative (a questionnaire targeting a cross-section of service recipients) and qualitative ( key informant interviews with LGI service providers) methods. The results revealed a poor level of citizen trust in UzPs, as the majority of respondents expressed dissatisfaction with their performance. This low level of citizens’ trust was attributable to such reasons as delays in service delivery, dishonest and unfair practices, and disrespectful treatment by service providers. From a ‘supply-side’ perspective, service providers mentioned many constraints to good performance including the challenge of meeting growing demand with inadequate resources, frequent staff transfers, limited scope for training on modern technologies, and pressure and interference from influential elites

Professional Ethics Under Islamic Perspective: A Study on Islamic Banks Operating in Bangladesh

The present study is about practice of professional ethics under Islamic perspective in Islamic Banks operating in Bangladesh. It is the outcome of primary data mainly. The requisite primary data were collected from a total number of 77 respondents on the basis of a structured questionnaire by direct interview methods from 7 Islamic banks operating in Bangladesh. The respondents were selected purposively for the easy and smooth collection of data. The main theme of the study is the practices of Islamic as well as professional ethics in the selected seven Islamic banks. The study depicts that awareness and attitudes towards the principles and practices of Islamic professional ethics have been higher is case of top level management of the banks. On the other hand, in case of the branch level management, those have been either medium or low. In order to improve the existing practice, the problems as mentioned in the study must be removed by adopting the suggestions opined by the respondents. Key words: Islamic professional ethics, Islamic management, Shariah compliance, Ethical behavior, Corporate social responsibility and Leadership