Showing papers by "Chittagong University of Engineering & Technology published in 2007"

Anti-inflammatory and analgesic alkaloid from Sida cordifolia linn.

Abstract: The analgesic and anti-inflammatory activities of a new alkaloid, 1,2,3,9-tetrahydro-pyrrolo [2,1-b] quinazolin-3-ylamine (compound 1) isolated from Sida cordifolia Linn. were investigated in animal models. In the acetic acid induced writhing model, the compound 1 showed 25.4 (P<0.05) and 52.43% (P<0.01) inhibition of writhing response at doses of 25 and 50 mg/kg body weight respectively. The alkaloid also produced significant increase in the tail flick latency in radiant heat tail-flick method. In Carrageenan induced rat paw edema the compound 1 produced 16.93 and 24.43 % inhibition of paw edema at the doses of 25 and 50 mg/kg body weight respectively at the third hour of study.

Three new flavonol c-glycosides from sida cordifolia linn

Abstract: Three new flavonol C-glycosides: 3′-(3″,7″-dimethyl-2″,6″-octadiene)-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucoside (1), 3′-(3″,7″-dimethyl-2″,6″-octadiene)-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl [1→4]-α-D-glucoside (2) and 6-(3″-methyl-2″-butene)-3′-methoxyl-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl [1→4]-β-D-glucoside (3) have been isolated from 80% ethanolic extract of the aerial parts of Sida cordifolia Linn followed by partitioning with ethyl acetate. Structures were established by chemical and spectroscopic methods.

Lexical Semantics: A Newapproach to Analyze the Bangla Sentence with Semantic Features

Abstract: Semantics is concerned with the meaning of words and a word with semantic features is corresponding to their sense component. Associating words with semantic features is useful in the field of machine translation. This paper present a methodology for analysis the Bangla sentences in semantic manner. This paper also focuses on the several primitive semantic features of Bangla words that are necessary for semantic analysis. Semantic features are shown in a tabular fashion with values indicating whether the features or inverse features are applicable and also whatever the features are redundant. Context free grammar and top-down approach have been used for the purpose of generating annotated parse tree with distinct semantic features in this paper. Model is tested for simple sentence of Bangla and test results reflect the successful results for most of the test cases.

Modeling and performance of TCP in a MC-CDMA system for 4G communications

Abstract: Market research finds that mobile commerce for 4G wireless systems will be dominated by basic human communication such as messaging, voice, and video communication. Because of its typically large bandwidth requirements, broadband communication is expected to emerge as the dominant type of traffic in 4G wireless systems. In this paper a new TCP based Multicarrier access technique named MC-CDMA for mitigating 4G requirements is proposed. This paper also presents analytical information regarding the transfer of TCP data flows on paths towards interconnected wireless systems, with emphasis on 4G cellular networks. The focus is on protocol modifications in face of problems arising from terminal mobility and wireless transmission. We advocate the use of TCP as the transport layer protocol for high-speed data in a Multi-Carrier CDMA (MC-CDMA) system for 4G wireless communications.

Sinr Performance of Multicarrier CDMA System in Frequency-Selective Rayleigh Fading Channels

Abstract: In this paper a new expression of the signal-to-interference-noise ratio (SINR) for single cell multicarrier code division multiple access (MC-CDMA) wireless system in a frequency-selective Rayleigh fading channel is derived and investigated. The expression is much simplified compared to previous research. The SINR performance in uplink channels with frequency-selective Rayleigh fading is shown by computer simulation. It is assumed that the proposed system suffers single path fading. Numerical results indicate that the system performs better than that of the conventional DS-CDMA system. The result of the analysis will provide relevant information to design the physical layer protocol for 4G mobile communications system.

Computation of triple differential cross-sections with the inclusion of exchange effects in atomic K-shell ionization by relativistic electrons for symmetric geometry

Abstract: The triple differential cross-section for K-shell ionization of silver and copper atoms by relativistic electrons have been computed in the coplanar symmetric geometry with the inclusion of exchange effects following the multiple scattering theory of Das and Seal [1] multiplied by suitable spinors. Present computed results are marginally improved in some cases from the previous computed results [2]. Present results are compared with measured values [3] and with previous computation results [2]. Some other theoretical computational results are also presented here for comparison.

Fuzzy Features Extraction from Bangla Handwriten Character

Abstract: Character is the fundamental attribute for writing and reading a language. Character recognition is the process to classify the input character according to the predefined character class. Fuzzy logic has proved to be a powerful tool to represent imprecise and irregular patterns. The most tedious job associated with fuzzy logic is the extraction of meaningful features. This paper describes a method to efficiently detect the meaningful fuzzy features including global features, geometric features and positional features from handwritten Bangla character respectively. We have tested our design for different types of Bangla handwritten alphabets in various style and we got successful features extraction results for most of the test cases.