Concurrent development model

See Concurrent Development Model, Incremental Development Model, Spiral Development Model, and System Life-Cycle Model for additional information. 

Product development models are the driving force for delivering the product to market on time and at the right cost. In general, the models in the literature can be divided into just two types sequential and concurrent. Each has its own characteristics, but there are several requirements that a new product development model should fulfil (Sum, 1992) ... 

The automotive sector s quality assurance standard QS 9000 (1998) suggests a concurrent high level model, as opposed to the sequential model from BS 7000 (1997). This is shown in Figure 5.7. The automotive industry in particular has embraced the use of concurrent engineering models for product development, and this is reflected in the standards which facilitate their quality assurance programmes. A concurrent industrial model from the automotive sector will be discussed later. 

Figure 2 also shows the variation of nearest-neighbor concurrence as the anisotropy parameter y decreases. For the XY model (y = 0), the concurrence for a = 0 is zero up to the critical point Xc = I and different from zero above Xc = 1. However, as a increases the concurrence develops steps and the... 

A fluidized-bed MTG concept was concurrently developed by Mobil. The process research went through several stages involving bench-scale fixed fluidized-bed 4-bbl/day and 100-bbl/day cold-flow models, and a 100-bbI/day semiwork plant. 

In this chapter, the emphasis has been placed on the chain of events leading to the use of catalysts on nearly all U.S. and Japanese automobiles in the 1975 model year. The sulfate issue has been covered through the events of 1976 because it threatened to result in the removal of catalysts from the emission control system, and was just reaching full bloom in September of 1974 when the 1975 catalyst-equipped cars were hitting the showrooms. The concurrent development of catalysts for the control of NOx by direct catalytic reduction or by simultaneous catalytic conversion of HC, CO and NOx, which were spurred by the inclusion of NOx standards in the... 

An assembly model can be considered as an advanced one when it is suitable for the description of all the information demanded by the above listed activities. The part oriented approach to the modeling of mechanical systems has been replaced by a more comprehensive and integrated approach that includes the modeling of assemblies and kinematics. In fact, assembly modeling has developed into a key position in concurrent associative modeling. 

When developing 3D-QSAR models, one should concurrently develop traditional QSARs, using, for example, some of the classical descriptors presented in the introductory section of this chapter. Regardless of the geometric features explained in a 3D-QSAR, other properties (e.g., hydrophobicity) may play important roles in the ligand-target interaction. Such factors may not be apparent from a standard CoMFA model. 

An approach for the automated validation of plant models is presented in (Abele et al. 2013). Inconsistencies in plant models may arise when integrating different engineering views on the plant created by different experts (e.g., mechanical and electrical engineers), who work concurrently on developing models for the same... 

Figure 5.6 Sequential versus concurrent model for product development (Maylor, 1996)...

Based on high performance liquid chromatography (HPLC) studies regarding the equilibration of isomeric fractions of P-carotene isomers at 45°C, a model consisting of two reversible concurrent isomerization reactions was developed by Pesek et al. 1990. Under dark storage conditions at 45°C, a P-carotene solution reached an equilibrium after 4-6 days yielding approximately 66% aW-trans-, 8% of 9-cis-, and 25% of 13-d.s-P-carotene. The observed rate constant (k) for the formation of the 13-d.v- isomer was faster than that of the 9-d.s-p-carotene isomer, and the back rate constants toward the all -trans- isomer were intrinsically faster as compared to the formation of d,v-isomcrs of P-carotene (Chart 12.1). 

The previous models were developed for Brownian particles, i.e. particles that are smaller than about 1 pm. Since most times particles that are industrially codeposited are larger than this, Fransaer developed a model for the codeposition of non-Brownian particles [38, 50], This model is based on a trajectory analysis of particles, including convective mass transport, geometrical interception, and migration under specific forces, coupled to a surface immobilization reaction. The codeposition process was separated in two sub-processes the reduction of metal ions and the concurrent deposition of particles. The rate of metal deposition was obtained from the diffusion... 

With object-oriented databases, the interlinked object model is transparently carried over to persistence, and the developer is concerned with logical things—transaction boundaries, concurrency, how far to propagate locks—rather than mapping between two dissimilar models. 

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