Temporal partitioning

Temporal partition is assurance that two components do not interfere with each other s allocated timeslots. Spatial partition is assurance that two components do not interfere with each other s resources (i.e., memory, processing, etc.). 

IMA is based upon two fundamental principles spatial partitioning and temporal partitioning. This partitioning ensures that the individual applications do not interfere or affect each other, either inadvertently or deliberately. The enforcement of these principles is achieved through the specific implementation of the IMA software architecture (timeslot scheduling in the case of ARINC 653) and MMU-enforced separation of partitions (for details of an example implementation of an ARINC 653 architecture, see (ARINC 2003)). 

Time and space partitioning is a way to ease the composable development of software applications, as well as to improve the overall safety of the system. Spatial partitioning ensures that a task in one partition is unable to change private data of another task in another partition. Temporal partitioning, on the other hand, guarantees that the timing characteristics of tasks, such as their worst-case execution times, are not affected by the execution of other tasks in other partitions. Consequently, time and space partitioning enforces two important features ... 

Almeida, L., Pedreiras, P. Scheduling within temporal partitions Response-time analysis and server design. In Proc. of the 4th ACM International Conference on Embedded Software (2004)... 

More precisely, the kernel starts by initializing itself and then the different partitions, which are to be executed in a predefined static order. The MPIC generates an interruption each time a dedicated counter reaches a specific value. The kernel uses the MPIC to implement the temporal partitioning between applications an interrupt is generated each time a time slot allocated for a particular partition ends up. The dedicated counter is then set to zero, the context of the current partition is backed-up and the context of the next partition to be executed is restored. Regarding the memory isolation, the MMU is used for spatial partitioning it controls the memory accesses in such a way that a partition cannot read or write application data used in the context of another partition. 

The use of fossil data and molecular clocks in systematics highlights the necessity to introduce the concept of time-slicing into comparative biogeography. Methods available for incorporating temporal information such as Parsimony Analysis of Endemicity (PAE), area cladistics, and Temporally Partitioned Component Analysis (TPCA), are discussed and compared to a synchronic approach. An analysis of these methods demonstrates the necessity for a synchronic approach and dispels the erroneous division between palaeo and neo biogeography. 

McKee BA, DeMaster DJ, Nittrouer CA (1983) Concepts of sediment deposition and accumulation applied to the continental shelf near the mouth of the Yangtze River. Geol 11 631-633 McKee BA, DeMaster DJ, Nittrouer CA (1986a) Temporal variability in the partitioning of thorium between dissolved and particulate phases on the Amazon shelf - implications for the scavenging of particle-reactive species. Cont Shelf Res 6 87-106... 

For convenience, these qualitative and quantitative absorption models have been classified into three categories based on their dependence on spatial and temporal variables [2], The first category is referred to as quasi-equilibrium models. The quasi-equilibrium model, including the pH-partition hypothesis... 

C.R. Yonzon, C.L. Haynes, X. Zhang, J.T. Walsh Jr. and R.P. Van Duyne, A glucose biosensor based on surface-enhanced Raman scattering improved partition layer, temporal stability, reversibility, and resistance to serum protein interference, Anal. Chem., 76(1) (2004) 78-85. 

Finally, it should be pointed out that Part III will add a new important element that we need to describe organic compounds in natural systems, that is, time. So far, we have dealt only with equilibrium concepts (e.g., with the partitioning of organic compounds between different phases), but we have not addressed the question of how fast such equilibria are reached. Thus, in Chapter 12 we will introduce the time axis, that is, we will describe the temporal evolution of a compound concentration due to the influence from various transformation and transport processes. In Part IV we will go one step further and also add space into our considerations. 

Al fundamental question about the interpretation of acidic aerosol data is whether researchers can characterize past and current atmospheric concentrations and distributions (spatial and temporal) with sufficient accuracy for studies of their effects on ecosystems and human health. Part of the answer to this question can be provided by a review of the methods that have been used to measure the strong acid content of aerosol particles collected from the atmosphere. This chapter serves as such a review, and, in evaluating analytical procedures, it specifically assesses the ability of each procedure to overcome sampling artifacts, to distinguish between strong and weak acids, to properly partition strong acidity between gas-phase and aero-sol-phase species, and to quantitate strong acidity at the levels at which it is found in the ambient atmosphere. 

---