RATE COMPATIBLE PUNCTURED TURBO-CODED HYBRID ARQ FOR OFDM SYSTEM

Now a day’s orthogonal frequency division multiplexing (OFDM) is under intense research for broadband wireless transmission because of its robustness against multipath fading. A major concern in data communication such as OFDM is to control transmission errors caused by the channel noise so that error free data can be delivered to the user. Rate compatible punctured turbo (RCPT) coded hybrid ARQ (RCPT HARQ) has been found to give improved throughput performance in a OFDM system. However the extent to which the RCPT HARQ improves the throughput performance of the OFDM system has not been fully understood. HARQ has been suggested as a means of providing high data rate and high throughput communication in next generation systems through diversity combining transmit attempts at the receiver. The combination of RCPT HARQ with OFDM provides significant bandwidth at close to capacity rates of channel. In this paper, we evaluate by computer simulations the throughput performance of RCPT code HARQ for OFDM system as compared to that of conventional OFDM

Design Principles for Two-Dimensional Molecular Aggregates Using Kasha's Model: Tunable Photophysics in Near and Short-Wave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. It is therefore necessary to develop materials that absorb light efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~800 nm to 1000 nm and 1050 nm respectively with sheet-like morphologies and high molar absorptivities (e ~ 105 M-1cm-1). We use Frenkel exciton theory to extend Kasha’s model for J and H aggregation and describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. I-aggregates hold potential for applications as charge injection moieties for semiconductors and donors for energy transfer in NIR and SWIR. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties

Environmental Management for Sustainable Growth in an Integrated Iron and Steel Plant

The manufacture of steel involves a large number of processing which lead to complex problems of environme-ntal pollution. Coke making and sintering are two of the major areas in so far as pollution is concerned. Slag constitutes the major portion of solid wastes. Waste generation adversely affects productivity and contributes to the high cost of production. It has been shown that improving the efficiency of operation and fuel saving measures help in reducing pollution in steel plants. Utilization of slag, mill scale, sludge and dusts, safe disposal of hazardous wastes and minimization of emissions of CO, C02, 502, NOx, cyanides, volatile organic compounds (VOC), NH3, suspended particulate matters (SPM) etc, are essential steps towards environmental management

Bio-activity of oils of Trigonella foenum-graecum and Pongamia pinnata

Different concentration of oils obtained from two plants species belonging to family Fabaceae i.e. Trigonella foenum-graecum and Pongamia pinnata were evaluated for their antifungal and antibacterial activity against Aspergillus niger, A. fumigatus, Staphylococcus aureus and Pseudomonas aeruginosa by MIC determination and dry-weight method. Both the oils showed high degree of antimycotic and antibacterial activity. P. pinnata oil was more effective as compared to oil of T. foenum-gracecum. A.niger and S. aureus were more sensitive to oil of P. pinnata. Chemical analysis of oils performed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS) showed the presence offatty acids

Corrosion Control of Kunifer-5 Seawater Piping Systems of Naval Ships by Cathodic Protection Technique

The cause of premature corrosion of Kunifer-5(copper alloy containing Ni 5 per cent and Fe 1.35 per cent) pipes used in seawater piping systems on board ships for feeding seawater to various units has been discussed. It has been shown that the Kunifer-5 alloys suffer from heavy corrosion-erosion attack at unavoidable bends and places where local seawater velocity exceeds the specified limit. The field observations as well as laboratory study have indicated that satisfactory protection of the pipes could be achieved by galvanic cathodic protection using aluminium alloy anodes

An Efficient Technique for mining Association rules using Enhanced Apriori Algorithm

There are Various mining algorithms of association rules. One of the most popular algorithm is Apriori that extracts frequent itemset from large database and getting the association rule for discovering the knowledge. this paper pitfalls the limitation of the original Apriori algorithm for wasting time for scanning the whole database searching on to the frequent itemsets, and presents an technique on Apriori by reducing that wasted time depending on scanning only some transactions whose support value is bigger than 25% of minimum Support is taken as frequent item set and is added to the frequent item sets and then rules are formed. An enhanced Apriori algorithm may find the tendency of a customer on the basis of frequently purchased item-sets The proposed algorithm is useful as a frequent item sets predictor with lower number of scans. DOI: 10.17762/ijritcc2321-8169.15063