Evaluación del rendimiento de bases de datos embebida: un estudio empírico

Introduction: With the rapid deployment of embedded databases across a wide range of embedded devices such as mobile devices, Internet of Things (IoT) devices, etc., the amount of data generated by such devices is also growing increasingly. For this reason, the performance is considered as a crucial criterion in the process of selecting the most suitable embedded database management system to be used to store/retrieve data of these devices. Currently, many embedded databases are available to be utilized in this context. Materials and Methods: In this paper, four popular open-source relational embedded databases; namely, H2, HSQLDB, Apache Derby, and SQLite have been compared experimentally with each other to evaluate their operational performance in terms of creating database tables, retrieving data, inserting data, updating data, deleting data. Results and Discussion: The experimental results of this paper have been illustrated in Table 4. Conclusions: The experimental results and analysis showed that HSQLDB outperformed other databases in most evaluation scenarios

Utilizing rapid prototyping 3D printer for fabricating flexographic PDMS printing plate

Recently printed electronic field is significantly growth. Printed electronic is to develop electrical devices by printing method. Conventional printing method that has been studied for this kind of printed electronic such as flexographic, micro contact printing, screen printing, gravure and ink jet. In flexographic and microcontact printing, a printing plate is used to transfer the designed and desired pattern to substrate through conformed contact. Therefore printing plate is play a big role in this area. Printing plate making by photopolymer which used in flexographic have limitation in achieving a micro-scale of pattern size. However, printing plate of microcontact printing have an advantages in producing micro, even nano-scale size by PDMS (Polydimethylsiloxane). Hence, rapid prototyping 3D printer was used for developing a PDMS micro-scale printing plate which will be used in reel to reel (R2R) flexographic due to high speed, low cost, mass production of this type of printing process. The flexibility of 3D printer in producing any shape of pattern easily, contributed the success of this study. A nickel plating and glass etching master pattern was used in this study too as master pattern mould since 3D printer has been reached the micro size limitation. The finest multiple solid line array with 1mm width and 2mm gap pattern of printing plate was successfully fabricated by 3D printer master mould due to size limitation of the FDM (Fused Deposition Modeling) 3D printer nozzle itself. However, the micro-scale multiple solid line array of 100micron and 25micron successfully made by nikel platting and glass etching master mould respectively. Those types of printing plate producing method is valueable since it is easy, fast and low cost, used for micro-flexographic in printed electronic field or biomedical application

On entropy, specific heat, susceptibility and Rushbrooke inequality in percolation

We investigate percolation, a probabilistic model for continuous phase transition (CPT), on square and weighted planar stochastic lattices. In its thermal counterpart, entropy is minimally low where order parameter (OP) is maximally high and vice versa. Besides, specific heat, OP and susceptibility exhibit power-law when approaching the critical point and the corresponding critical exponents $\alpha, \beta, \gamma$ respectably obey the Rushbrooke inequality (RI) $\alpha+2\beta+\gamma\geq 2$. Their analogues in percolation, however, remain elusive. We define entropy, specific heat and redefine susceptibility for percolation and show that they behave exactly in the same way as their thermal counterpart. We also show that RI holds for both the lattices albeit they belong to different universality classes.Comment: 5 pages, 3 captioned figures, to appear as a Rapid Communication in Physical Review E, 201