A nonlinear multiple criteria model base for the problem of balancing caseload risk in probation departments

This paper presents a combined statistical model for probationer risk classification and nonlinear multi-criteria programming resource allocation model for workload balancing. A statistical model of individual probationer failure was used to classify individuals as high, medium or low risk for probation purposes. The proportion of probationers in each risk category was used as an input into the integer, nonlinear resource allocation model where the decision variables were the number of visits to probationers by type of visit and risk classification.     

Rubber-toughening of plastics

The effects of matrix ductility upon mechanisms of rubber toughening have been studied in a set of materials having identical rubber contents, but differing in matrix composition. The materials were made by solution blending 50% of HIPS (high-impact polystyrene) with polystyrene and PPO^® poly-(2, 6-dimethyl-1, 4-phenylene oxide) in varying proportions. Crazing was studied quantitatively by measuring volume changes during creep. Analysis showed that in blends of HIPS with polystyrene, crazing is the only significant mechanism of tensile creep, whereas in blends containing polyphenylene oxide, shearing mechanisms are also important, and the contribution of crazing to creep deformation can be as low as 30%, depending upon matrix composition. Scanning electron microscopy showed that both crazes and shear bands were present in strained HIPS/PPO blends. Shear band formation appears to be responsible for the increased fracture resistance of blends containing a high proportion of polyphenylene oxide. A theory of toughening is proposed for these blends.     

Correspondence

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Second-generation laser firefly clusters: improved scheme for distributed sensing in the atmosphere

We present an improved concept of laser firefly clustering for atmospheric probing, elaborating on previous published work. The laser firefly cluster is a mobile, flexible, and versatile distributed-sensing system, whose purpose is to profile the chemical and the particulate composition of the atmosphere for pollution monitoring, meteorology, detection of contamination, etc. The fireflies are deployed in situ at the altitude of interest and evoke a backscatter response from aerosols and molecules in the immediate vicinity by using a coded laser signal. The enhanced, second-generation system affords better performance at lower energy cost and has a considerably increased scope of application. A numerical example demonstrates the potential of the innovative system.     

Calorimetric study of flammable fabrics. II. Analysis of flame retardant-treated cotton

Efficiencies of three flame retardants for cellulose, phosphoric acid, diammonium phosphate, and THPOH ammonia finish, have been evaluated based on the heat release value and the rate of heat release of treated fabrics burning in air measured with the isoperibol calorimeter. The results were compared and correlated with those obtained previously with the bomb-calorimetric technique. Complete heat balances were obtained for the systems studied by correlation of the calorimetric data and the measurement of combustible gases evolved from the fabric burning in air. The rate of heat release was found to correlate with the flame propagation rate measured at a 45° angle. The results from the heat, rate, and combustible gas measurements were interpretable in terms of existing mechanisms of flame-retardant action.     

Building HCI partnerships and infrastructure

As policymakers and technology planners respond to the growing activity in human—computer interaction, a broad perspective may be helpful. This article offers a top-down view of current activities and suggests opportunities and challenges for the continued growth of HCI. Partnerships among universities, corporations, government agencies, and professional societies are proposed. Infrastructure needs to support this new discipline are outlined.     

Swimmer risk of gastrointestinal illness from exposure to tropical coastal waters impacted by terrestrial dry-weather runoff

This study used molecular methods to measure concentrations of four enteric viruses (adenovirus, enterovirus, norovirus GI, and norovirus GII) and fecal source tracking markers (human, ruminant, and pig Bacteroidales) in land-based runoff from 22 tropical streams on O'ahu, Hawai'i. Each stream was sampled twice in the morning and afternoon during dry weather. Viruses and human Bacteroidales were widespread in the streams. Watershed septic tank densities were positively associated with higher occurrence of human Bacteroidales and norovirus. There were no associations between occurrence of viruses and fecal indicator concentrations. Virus concentrations and previously reported culturable Salmonella and Campylobacter were used as inputs to a quantitative microbial risk assessment (QMRA) model to estimate the risk of acquiring gastrointestinal (GI) illness from swimming in tropical marine waters adjacent to discharging streams. Monte Carlo methods were used to incorporate uncertainties in the dilution of stream discharge with seawater, swimmer ingestion volumes, pathogen concentrations, and dose-response parameters into the model. Median GI illness risk to swimmers from exposure to coastal waters adjacent to the 22 streams ranged from 0 to 21/1000. GI illness risks from viral exposures were generally orders of magnitude greater than bacterial exposures. Swimming adjacent to streams positive for norovirus or adenovirus resulted in the highest risks. The median risk adjacent to each stream was positively, significantly correlated to the concentration of Clostridium perfringens in the stream. Although a number of important assumptions were made to complete the QMRA, results suggest land-based runoff in the tropics as a potential source of GI illness risk, with pathogens coming from both human and nonhuman nonpoint sources including septic tanks.