Minimum Number of Probes for Brain Dynamics Observability

In this paper, we address the problem of placing sensor probes in the brain such that the system dynamics' are generically observable. The system dynamics whose states can encode for instance the fire-rating of the neurons or their ensemble following a neural-topological (structural) approach, and the sensors are assumed to be dedicated, i.e., can only measure a state at each time. Even though the mathematical description of brain dynamics is (yet) to be discovered, we build on its observed fractal characteristics and assume that the model of the brain activity satisfies fractional-order dynamics. Although the sensor placement explored in this paper is particularly considering the observability of brain dynamics, the proposed methodology applies to any fractional-order linear system. Thus, the main contribution of this paper is to show how to place the minimum number of dedicated sensors, i.e., sensors measuring only a state variable, to ensure generic observability in discrete-time fractional-order systems for a specified finite interval of time. Finally, an illustrative example of the main results is provided using electroencephalogram (EEG) data.Comment: arXiv admin note: text overlap with arXiv:1507.0720

Semantic Analysis of Macro Usage for Portability

C is an unsafe language. Researchers have been developing tools to port C to safer languages such as Rust, Checked C, or Go. Existing tools, however, resort to preprocessing the source file first, then porting the resulting code, leaving barely recognizable code that loses macro abstractions. To preserve macro usage, porting tools need analyses that understand macro behavior to port to equivalent constructs. But macro semantics differ from typical functions, precluding simple syntactic transformations to port them. We introduce the first comprehensive framework for analyzing the portability of macro usage. We decompose macro behavior into 26 fine-grained properties and implement a program analysis tool, called Maki, that identifies them in real-world code with 94% accuracy. We apply Maki to 21 programs containing a total of 86,199 macro definitions. We found that real-world macros are much more portable than previously known. More than a third (37%) are easy-to-port, and Maki provides hints for porting more complicated macros. We find, on average, 2x more easy-to-port macros and up to 7x more in the best case compared to prior work. Guided by Maki's output, we found and hand-ported macros in four real-world programs. We submitted patches to Linux maintainers that transform eleven macros, nine of which have been accepted.Comment: 12 pages. 4 figures. 2 tables. To appear in the 2024 IEEE/ACM 46th International Conference on Software Engineering (ICSE '24), April 14-20, 2024, Lisbon, Portugal. See https://zenodo.org/doi/10.5281/zenodo.7783131 for the latest version of the artifact associated with this pape

VALUE CO-CREATION AND TRUST IN SOCIAL COMMERCE: AN FSQCA APPROACH

This study aims to explain how value co-creation, between customers and companies, and key aspects of trust combine to influence customers’ purchase intentions in social commerce. Value co-creation is decomposed into two attributes, behavioral alignment, and empowerment and control, while trust is measured through the aspects of trusting beliefs, institutional trust, and disposition to trust. In order to examine the interplay of these factors and their combined effect on purchase intentions in social commerce, a conceptual model is developed and examined on a data sample of 379 users with experience in social commerce, through fuzzy-set qualitative comparative analysis (fsQCA). The findings indicate five configurations that lead to high intentions to purchase in social commerce, and three configurations that inhibit purchase intentions. The outcomes of the analysis show that value co-creation may be more important than trust in achieving high purchase intentions, while avoiding low/medium purchase intentions. This study contributes to the social commerce literature by demonstrating how value co-creation and trust interrelate and how their interplay influences purchase intentions

Proximity effecs and curie temperature enhancement in Co/EuS and Fe/EuS multilayers

Two identical Co/EuS and Fe/EuS multilayers of six periods each and with individual layers of about 4 nm thick are grown by e-beam evaporation under ultrahigh vacuum conditions. The films show polycrystalline structure with a grain size limited by the individual layer thickness. Both multilayers consist of almost continuous layers with some roughness. The surface peak-to-peak roughness is about 4–5 nm. Magnetization measurements and calculations of the loops based on a Stoner–Wohlfarth-like model allow us to determine the direct antiferromagnetic exchange coupling constant between the 3d metal and EuS at 5 K. Both samples show strong enhancement of the Curie temperature of EuS up to at least 50 K with a EuS magnetization tail, which persists up to about 100 K. The J = 7/2 character of the EuS layers is shown to be responsible for the large Curie temperature enhancement

Band-gap tuning at the strong quantum confinement regime in magnetic semiconductor EuS thin films

Ultraviolet-visible absorption spectra of nanoscaled EuS thin films reveal a blue shift of the energy between the top-valence and bottom-conduction bands. This band-gap tuning changes smoothly with decreasing film thickness and becomes significant below the exciton Bohr diameter ~3.5nm indicating strong quantum confinement effects. The results are reproduced in the framework of the potential morphing method in Hartree Fock approximation. The large values of the effective mass of the holes, due to localization of the EuS ƒ-states, limit the blue shift to about 0.35eV. This controllable band-gap tuning of magnetic semiconductor EuS renders it useful for merging spintronics and optoelectronics