The Use of Soft Systems Methodology in Practice

This paper reports the results of a survey intended to discover the extent to which Checkland's Soft Systems Methodology (SSM) is used in practice. Some 300 questionnaires were sent to people who had had some exposure to SSM and, surprisingly, nearly half were returned. The majority described in detail their uses of SSM and most felt that it had been successful. This paper describes the overall quantitative results from the survey as well as presenting a qualitative analysis of the experiences of using SSM.     

Local radial Phragmén-Lindelöf estimates for plurisubharmonic functions on analytic varieties

We give a sufficient condition for a local radial Phragmén-Lindelöf principle on analytic varieties. This condition is expressed in terms of existence of hyperbolic directions.

     

Nanostructures in calcia stabilized hafnia thin films observed by PAC as a function of temperature

The hyperfine quadrupole interaction at Hf sites in films and powders of 14 mol% CaO–HfO₂ and 20 mol% CaO–HfO₂ has been determined as a function of temperature. Results indicate the formation of a cubic solid solution and other microstructures assigned to the ?₁ (CaHf₄O₉) and ?₂ (Ca₆Hf₁₉O₄₄) phases. Dynamical effects on the electric field gradient reveal the existence of oxygen vacancies movements in the solid solution. The thermal behavior of the relaxation constant observed in films allowed the determination of activation energies of 0.54 eV and 0.70 eV for the 14 mol% and 20 mol% CaO doped hafnias, respectively. The influence of the microdomains and the stability of the cubic solid solution are discussed.     

Red picosecond pulses generated by frequency doubling a Raman amplified widely tunable 1.3 microm fiber ring laser

We generated 0.66 microm picosecond pulses by second-harmonic generation of the Raman amplified output of a 1.3 microm actively mode-locked fiber ring laser in a periodically poled potassium titanyl phosphate (PPKTP) waveguide. The ring laser produced 9 ps pulses at a 20 GHz repetition frequency, was tunable over 1284-1330 nm, and was based on a semiconductor optical amplifier and a Mach-Zehnder amplitude modulator. The Raman amplifier served both to amplify the ring laser and to compress the pulses as solitons. The spectral flexibility of the amplifiers and the modulator should enable similar configurations to be made at other wavelengths and facilitate efficient frequency doubling in waveguides to other visible wavelengths.     

Intrinsic fiber Fabry-Perot temperature sensor with fiber Bragg grating mirrors

A fiber Fabry-Perot interferometer (FFPI) sensor is formed with broadband (~3 nm, 3-dB bandwidth) fiber Bragg grating (FBG) mirrors. Repetitively modulating a distributed-feedback laser produces chirping that modulates the reflectance of the FFPI. Because the reflectance of the FBG mirrors varies with optical frequency, the fringes in the sensor reflectance modulation are distinguishable, making it possible to extend the sensor dynamic range versus that of a FFPI sensor with conventional wavelength-dependent mirrors. An ambient temperature is determined in the range from 25 to 170 degrees C with a resolution of 0.005 degrees C.     

Subpicosecond pulse generation in synchronously pumped and hybrid ring dye lasers

Subpicosecond pulse generation has been examined in synchronously pumped mode-locked ring dye laser systems. These include hybrid and composite absorber/gain media arrangements as well as a simple synchronous cavity. The shortest pulses recorded were 0.3 ps for the hybrid system, and this has been shown to be critically dependent on the positioning of the absorber jet in the centre of the cavity to better than 50 m. Stable operation for subpicosecond pulse generation has been achieved in the ring configuration with greater wavelength tunability and higher average power conversion efficiency than with conventional cavity arrangements.