Pseudo-analog speech transmission in mobile radio communicationsystems

A low-complexity pseudo-analog speech transmission scheme is proposed for portable communications. It uses a speech coder based on adaptive differential pulse code modulation (ADPCM) in combination with a multilevel digital modulation technique such as M-ary DPSK or M-ary FSK and features low quantization noise, bandwidth efficiency, and robustness to transmission errors. A nonsymmetric M -ary DPSK scheme called skewed M-ary DPSK is proposed to enhance the noisy channel performance. Comparison to conventional analog FM and a digital speech transmission scheme using adaptive predictive coding and forward error correction (FEC) based on convolutional coding shows that the pseudo-analog system has the best objective signal-to-noise ratio performance under most channel conditions. Informal subjective evaluations rate the digital system superior to the pseudo-analog scheme for bad channels and conversely for good channels. It is concluded that the pseudo-analog system can be designed with low delay and high speech quality for good channels with high spectral efficiency     

Antrochonal polyp: a case report of treatment with intranasal steroids

The aetiology of antrochonal polyps is unknown. We report one case where treatment with topical intranasal cortico-steroids was successful. We are not aware of any previous reports of medical treatment.     

A theoretical study of parallel flow condensation with interfacial drag in an annulus

The in-tube condensation model of Bae, Maulbetsch and Rohsenow (BMR) is extended to condensation in an annulus with coolant on the tube side. An iterative calculation procedure is developed and used for predicting the variations of local condensing heat transfer coefficient, quality and wall temperature with condenser length for the systems-steam and Freon-12. Comparison of the predictions with Shah's correlation suggests the applicability of BMR's model for the annulus condensation.     

The Architecture of the Dalí Main-Memory Storage Manager

Performance needs of many database applicationsdictate that the entire database be stored in main memory.The dali system is a main memory storage manager designed toprovide the persistence, availability and safety guarantees one typically expects from a disk-resident database, while at the same time providing very high performance by virtue of being tuned to support in-memory data.User processes map the entire database into their address space andaccess data directly, thus avoiding expensive remote procedure calls andbuffer manager interactionstypical of accesses in disk-resident commercial systems available today.dali recovers the database to a consistent state in the case of system as well as process failures. It alsoprovides unique concurrency control and memory protection features, aswell as ordered and unordered index structures. Both object-oriented and relational database management systems have beenimplemented on top of dali. dali provides access to multiple layers ofapplication programming interface, including its low-level recovery,concurrency control and indexing components as well as its high-levelrelational component. Finally, various features of dali can be tailored tothe needs of an application to achieve high performance–for example,concurrency control and logging can be turned off if not desired, enablingdali to efficiently support applications that requirenon-persistent memory-resident data to be shared by multiple processes.     

CONDENSATION AND BOILING OF A BINARY AZEOTROPE ON A POROUS BOILING SURFACE

An experimental study was carried out to check the condensate quality when an azeotropic vapor of ethanol-water was passed over a cooled porous boiling tube. The ethanol composition was different from the azeotropic composition at some places on the tube. Overall, there was a net depletion of ethanol in the condensate. When the same azeotropic mixture was pool-boiled on a porous boiling surface, there was a net enrichment of ethanol in the vapor phase. A heteroazeotrope. butanol-water, on condensation, did not show any difference in composition between the vapor and liquid phases. An explanation based on surface capillarity is given for these effects.     

Determination of Vanadium Valence State in CaO-MgO-Al2O3-SiO2 System By High-Temperature Mass Spectrometry

In the present study, the applicability of the high-temperature mass spectrometric method combined with Knudsen effusion cell for quantifying the valence states of V in the multicomponent system CaO-MgO-Al₂O₃-SiO₂-VO _x up to a maximum temperature of 2050 K (1777 °C) was examined. The valence ratio of V³⁺/V⁴⁺ in slag phase was derived from the partial pressures of VO and VO₂ in the effused vapor phase. The results show good agreement with the literature values obtained by other techniques. A correlation between the valence ratio V³⁺/V⁴⁺ and the oxygen partial pressure as well as basicity was achieved based on the present results and accessed data in the literature. The results of the present study demonstrate that the Knudsen cell-mass spectrometric method can be a very effective tool in estimating the valence ratios for of transition metals in metallurgical slags.