Adaptive space-time reduced-length MMSE receiver for interferencesuppression in DS/CDMA

The authors present an adaptive space-time reduced-length minimum mean-squared error (MMSE) receiver to suppress co-channel interference in the near-far environment for an asynchronous direct-sequence code-division multiple-access (DS/CDMA) system. Simulation results show that better bit-error rate and faster and more stable convergence are achieved over the existing full- and reduced-length MMSE receivers     

Experimental study on a quasi-optical mode converter for transforming the whispering-gallery mode into a circularly polarized hollow radiation beam

An experiment was carried out for transforming the 120 GHz-TE_12.2 whispering-gallery mode (WGM) into a circularly polarized hollow radiation beam. A hollow beam was formed by reflecting the WGM, which was radiated from a 16 mm radius circular waveguide cut, with an annular mirror having suitable local normal vectors. The experimentally observed field intensity profiles of the reflected wave were in good agreement with calculated results.     

Model for the potential barrier depth along the grain boundaries of an ultrathin tin dioxide gas sensor

A potential barrier model along the grain boundaries in ultrathin tin dioxide (SnO₂) gas sensors is presented. It is assumed that the negatively charged oxygens are adsorbed only on the grain boundaries. The potential barrier depth is expressed as functions of grain size, donor concentration and surface coverage of adsorbed oxygen ions at the boundaries. A direct consequence is that the conduction electrons are effectively confined in a grain when the film thickness becomes smaller than a critical value. This indicates a drastic increase in resistivity with decreasing film thickness in air, and thus an occurrence of an extremely high gas sensitivity.     

Optoelectronics in satellite designs

Design of artificial satellites for communication, remote sensing and scientific investigations follows, at present, a fixed pattern based on existing and proven technologies and the requirements of payload or experiment within the constraints of weight, volume and power available. The advances in optoelectronic components and systems have opened up a new dimension in designing satellites of the future, incorporating new technologies. This paper deals with general satellite design concepts based on optoelectronic systems wherever applicable.     

Micro-Raman spectroscopy study of the process of microindentation in polymers

The residual deformation produced by Vickers microindentations in poly(3,3-dimethyl oxetane) (PDMO) was analysed by Raman microspectroscopy. Microstructural variations were observed as the Raman spectra were recorded at different positions along and out of the microindentation. A gradual distribution of the monoclinic and orthorhombic structures arises as the spectra were scanned from the centre to the edge of the impression area. This crystalline variation in PDMO, which reflects the degree of stress present on the surface of the sample, was utilized to obtain information on the distribution of pressure in and around the microindentation. In addition to the clear variation of pressure inside the permanently deformed region, no crystalline transformation was noted out of the impression area. Similar features were observed when the Raman spectra were recorded along one of the diagonals of the indentation.     

A mathematical model for the prediction of temperature in a dry snow layer

A mathematical model for predicting the temperature in a homogeneous layer of dry snow is presented. The model, which is physically based, is capable of predicting diurnal temperature behaviour at the snow surface and at any depth within a snow layer given the variation in a limited set of meteorological parameters over that period. A sensitivity analysis is performed to determine the important parameters in the prediction of snow surface temperatures. These are found to be consistent with simple physical reasoning.     

A transgenic T cell receptor restores thymocyte differentiation in interleukin-7 receptor alpha chain-deficient mice

Traffic accidents are a well-known public health problem worldwide. In Mexico research into risk factors for motor involving vehicles accidents and their consequences has recently been taken into account. The relevant literature does not normally describe the methodological aspects involved in the collection of primary data, since most studies have used secondary data the good quality and validity of which are assumed. The paper presented seeks to discuss and share with researchers in this field, some of the methodological aspects to be considered in the attempt to recreate the scene of the accident and obtain information approximating to reality. The measurements in situ of, such traffic accident variables as injury, use of seat belt, speed and alcohol intake are discussed.     

Persistent caching: an implementation technique for complex objectswith object identity

Many recent complex object database systems support the concepts of object identity and object identifier. Following an object identifier to access the referenced object is called navigation operation and is an essential operation in dealing with complex objects. Navigation operation is a difficult operation to implement efficiently since every navigation operation inherently causes one disk access operation. A scheme to notably accelerate the navigation operation among a sea of complex objects, by increasing the effective number of objects in one disk page is proposed. The main concept of the presented technique is threefold. The first idea is to store a cached value within a complex object that is referencing another complex object. The second is that when the referenced object is to be updated the update propagation is delayed until the time when the cached value is referenced. The third is to utilize a hashed table on main memory to efficiently validate the consistency between the cached values and the original values     

Cars, phones, and Tamagotchi tribes

As if life isn't already crowded enough with obligations, “Tamagotchis” (virtual pets) would seem to be at odds with the Information Age, but cars, phones and TV-like appliances will become more like Tamagotchis as the friction-free economy once again expresses itself in tribalism. My premise is simple: the friction-free economy rewards retro-cultures that yearn to return to agrarian tribalism. Selling hi-tech products in this new economy becomes ritual, and the greater the ritual, the greater the financial rewards. Some may use different names-database marketing, targeting or niche marketing-but the key to expanding the computer industry will be to build a tribe around your brand and flaunt it. Successful product design and sales will increasingly require targeting products, services and ideas to various tribes. An idea long understood in the entertainment and services industry, this is only now becoming a computer industry mantra. The question is, how will this impact the design of future computer products? Study the Tamagotchi and other Christmas season best-sellers to find out