INESC-ID

About: INESC-ID is a nonprofit organization based out in Lisbon, Portugal. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 932 authors who have published 2618 publications receiving 37658 citations.

Shape Analysis of the Femoral Head: A Comparative Study Between Spherical, (Super)Ellipsoidal, and (Super)Ovoidal Shapes.

Abstract: In this work, MacConaill's classification that the articular surface of the femoral head is better represented by ovoidal shapes rather than purely spherical shapes is computationally tested. To test MacConaill's classification, a surface fitting framework was developed to fit spheres, ellipsoids, superellipsoids, ovoids, and superovoids to computed tomography (CT) data of the femoral proximal epiphysis. The framework includes several image processing and computational geometry techniques, such as active contour segmentation and mesh smoothing, where implicit surface fitting is performed with genetic algorithms. By comparing the surface fitting error statistics, the results indicate that (super)ovoids fit femoral articular surfaces better than spherical or (super)ellipsoidal shapes.

Towards choosing better primes for spoken dialog systems

Abstract: When humans and computers use the same terms (primes, when they entrain to one another), spoken dialogs proceed more smoothly. The goal of this paper is to describe initial steps we have found that will enable us to eventually automatically choose better primes in spoken dialog system prompts. Two different sets of prompts were used to understand what makes one prime more suitable than another. The impact of the primes chosen in speech recognition was evaluated. In addition, results reveal that users did adopt the new vocabulary introduced in the new system prompts. As a result of this, performance of the system improved, providing clues for the trade off needed when choosing between adequate primes in prompts and speech recognition performance.

Integration of storage systems in distribution networks through multiobjective optimization

Abstract: The use of storage systems in distribution networks allows smoothing the load diagram. In fact, the cost of energy is different along the day and companies can be encouraged to use these systems, since the extra energy required to charge the storage system can be obtained in periods where the cost of the energy is lower and used in periods when the energy cost is higher. Storage systems also allow reducing losses of the lines and improving voltage profile. However, in distribution networks there are benefits in using distributed storage instead of centralized storage. Under this context, this paper proposes a multiobjective optimization approach for the location and sizing of storage systems. In this problem, the objective functions are in conflict. Increasing the number of storage systems leads to a reduction in the peak power and losses, but also will increase the investment cost. This approach allows obtaining solutions of different trade-offs with respect to the two objectives. An IEEE 69 buses and a real 94 buses test feeders are used to demonstrate the effectiveness of the proposed approach.

Multi-market optimal scheduling of a power generation portfolio with a price-maker pumped-storage hydro unit

Abstract: The increasing integration of renewables in the energy markets has been raising some challenges to generating companies (GENCOs), in terms of operation and planning of their generation portfolios. A GENCO aiming at maximizing its profits has to deal with offers to several available markets, among which are the Day-ahead Market (DAM) and the Secondary Reserve Market (SRM). This paper presents a scheduling solution of a price-maker GENCO whose portfolio includes a pumped-storage hydro unit, acting simultaneously in the DAM and SRM. The results were obtained for six different scenarios, where the portfolio may include a thermal generation unit and compares the GENCO behavior in both markets either as a price-taker or as a price-maker. The results put in evidence the portfolio effect when the GENCO takes into account its influence on price, which is seen in the price-maker scenarios, whereas the scheduling remains unchanged under the price-taker behavior.

Design of low-complexity digital finite impulse response filters on FPGAs

Abstract: The multiple constant multiplications (MCM) operation, which realizes the multiplication of a set of constants by a variable, has a significant impact on the complexity and performance of the digital finite impulse response (FIR) filters. Over the years, many high-level algorithms and design methods have been proposed for the efficient implementation of the MCM operation using only addition, subtraction, and shift operations. The main contribution of this paper is the introduction of a high-level synthesis algorithm that optimizes the area of the MCM operation and, consequently, of the FIR filter design, on field programmable gate arrays (FPGAs) by taking into account the implementation cost of each addition and subtraction operation in terms of the number of fundamental building blocks of FPGAs. It is observed from the experimental results that the solutions of the proposed algorithm yield less complex FIR filters on FPGAs with respect to those whose MCM part is implemented using prominent MCM algorithms and design methods.