Francesca Mele

NEMO is an example of a memory-bound code, where computational performance is limited by memory bandwidth due to intensive main memory access. This can be mitigated by more efficient use of the memory hierarchy, ensuring that data is held in fast low-level cache for as long as possible. Loop blocking or “tiling” is one way of achieving this, by partitioning loops so that data access is divided into smaller blocks that fit into cache.This optimisation technique has been applied to several numerical ocean models, including MITgcm, ROMS and CROCO. We describe an implementation of tiling in the NEMO 4.2 release candidate and its performance in realistic global configurations.The MPI domain is partitioned horizontally (over latitude and longitude) by modifying DO loop bounds and local working array declarations. A DO loop at the time-stepping level iterates over the tiles asynchronously. Lateral boundaries use an extended halo (two points wide instead of one) so that MPI communications can be suppressed when the tiling is active. Tiling has so far been implemented in the active tracer, vertical diffusion and dynamical code sections of NEMO.Tiling of the longitudinal axis always results in a loss of performance while tiling of the latitudinal axis can perform very well, reducing the execution time of individual code sections by up to 40% in ORCA2 simulations. However, this is offset against the cost of additional calculations due to the two-point halo, which increases the execution time of individual code sections by up to 15%. Additionally, the number of calculations is proportional to the number of tiles, further reducing potential performance gains from the tiling. This can be mitigated by removing halo calculations where possible.Overall tiling performance in ORCA025 is significantly worse compared to ORCA2. This is because a greater proportion of time is spent in code that is not tiled (75% in ORCA025 vs 45% in ORCA2) and because the performance of some tiled code is worse. Tiling in the vertical, as well as the horizontal, not only recovers the performance of this tiled code but improves it beyond that in the ORCA2 simulations.

The paper presents an innovative gapless traceability system able to improve the main business processes of the fresh vegetables supply chain. The performed analysis highlighted some critical aspects in the management of the whole supply chain, from the land to the table of the end consumer, and allowed us to reengineer the most important processes. In particular, the first steps of the supply chain, which include cultivation in greenhouses and manufacturing of packaged vegetables, were analyzed. The re-engineered model was designed by exploiting the potentialities derived from the combined use of innovative Radio Frequency technologies, such as RFID and NFC, and important international standards, such as EPCglobal. The proposed tracing and tracking system allows the end consumer to know the complete history of the purchased product. Furthermore, in order to evaluate the potential benefits of the reengineered processes in a real supply chain, a pilot project was implemented in an Italian food company, which produces ready-to-eat vegetables, known asIV gammaproducts. Finally, some important metrics have been chosen to carry out the analysis of the potential benefits derived from the use of the re-engineered model.

This paper evaluates the impact of the EPCglobal international standard and some emerging Radio Frequency (RF) technologies, such as Radio Frequency IDentification (RFID) and Near Field Communication (NFC), on the main processes of the fresh vegetables supply chain. Particular attention was focused on the first steps of the supply chain, which include cultivation in greenhouses and manufacturing of packaged vegetables, known as IV gamma products (i.e., goods ready to be consumed), because they represent crucial points of the considered supply chain. A qualitative and quantitative analysis of the current business processes was performed exploiting the experience of a big Italian company, with several locations and different brands. This analysis highlighted some critical aspects in the management of the whole supply chain, from the land to the table of the end-consumer, and allowed us to perform an efficient re-engineering of the main business processes. The re-engineered model was designed by exploiting the potentialities derived from the combined use of innovative technologies, including EPCglobal, RFID, NFC, and DataMatrix. Moreover, this work has led to the definition of important guidelines able to substantially improve both the culture techniques and the vegetables transformation procedures, based on strategic concepts such as precision agriculture, item-level traceability, and integration of heterogeneous Information Systems (IS). The proposed tracing and tracking system, based on EPCglobal standard, is able to guarantee to end-consumer the ability to know the entire history of the purchased product. Moreover, in order to evaluate the potential benefits of the re-engineered processes in a real supply chain, some metrics able to compare the current (AS IS) and reengineered (TO BE) models were considered. In particular, the Key Performance Indicator (KPI) method has been chosen to carry out this analysis on the pilot project implemented in the chosen company. Experimental results allowed us to derive a realistic estimate of the selected performance indicators for the re-engineered model.