We describe a novel text compressor which combines Ziv-Lempel compression and arithmetic coding with a form of vector quantisation. The resulting compressor resembles an LZ-77 compressor, but with no explicit phrase lengths or coding for literals. An examination of the limitations on its performance leads to some predictions of the limits of LZ-77 compression in general, showing that the LZ-77 ...

Domain Base Model checker refinements Transition system Temporal formula Spurious counterexample — > ¢¤ £¥¦ §© ̈ a « ¬ is the simplest model on which to check a formula yet achieving the same precision as does. R. Giacobazzi and I. Mastroeni:Domain Compression for Complete Abstractions – p.14/15 Future works: Geometry of Domain Transformers Compressor Compressor join−unif Obfuscator Ofuscator uc...

Improvement of compressor efficiency using the alternative refrigerant is demanded strongly to reduce CO2 emission, which causes the global warming. Especially the compressor using in frozen temperature level has long lifetime, and the correspondence to above-mentioned is one of the most important subjects. The scroll compressor is the promising structure to solve this problem. A technical poin...

The deflection of the crankshaft which transfers the power of motor to the pump of the compressor directly affects the vibration, noise and wear problems in the rotary compressor, therefore, with the requirement of higher reliability, it is important to obtain it exactly in compressor design. Various forces that the crankshaft suffers are calculated by theoretical analysis in the operation proc...

As refrigeration compressor manufacturers introduce machines with improved efficiencies there is a need for updating performance data. The compressor performance data which is published should be a true representation of the actual compressor performance, historically this has resulted in lengthy test programmes for the compressor manufacturer. A system is required which can accurately produce ...

Stable operation of both axial and radial compressors is constrained by the occurence of aerodynamic flow instabilities: rotating stall and surge. Developments in the understanding of the physics behind these instabilities and ideas of how t o stabilize the compressor system, have opened the door t o a new era in the field of compressor control. This study gives an overview of the current state...

To evaluate the effects of the thermal properties of components on the overall temperature distribution of a compressor, a heat transfer model employing the lumped thermal conductance approach has been formulated. The model has been verified with extensive measurements and the overall discrepancy of less than 7% is obtained. The discrepancies in the prediction are mainly the results of assumpti...

Motivated by the increase in storage space and Internet connection speed, as well as significant improvements in audio hardware, the interest for lossless audio compression has been greatly increasing, especially in the consumer market. In this article, we present a short performance comparison of the state of the art lossless audio compressors. The focus is on the OptimFROG symmetrical compres...

The profile gradient method has been recently introduced as a means of generating screw compressor rotor profiles. As a single parameter method, this procedure is convenient for the optimisation of screw compressor rotors and evaluating their quality. In this paper, the procedure is modified to adopt the pressure angle instead the profile gradient and applied to a screw compressor rotor rack. O...

There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such m...