Carlos Pinzon

• University of Guayaquil

The perovskite solar cells (PSCs) have excellent optoelectronic properties due to their tunable band gap, large carrier mobility, high absorption coefficient, and long diffusion lengths, making them great candidates for photovoltaic applications. Additionally, these devices have a simpler fabrication process and a lower cost compared to conventiona...

Consider a set of users, each of which is choosing and downloading one file out of a central pool of public files, and an attacker that observes the download size for each user to identify the choice of each user. This paper studies the problem of padding the files to obfuscate the exact file sizes and minimize the expected accuracy of the attacker...

One of the main concerns about fairness in machine learning (ML) is that, in order to achieve it, one may have to trade off some accuracy. To overcome this issue, Hardt et al. (Adv Neural Inf Process Syst 29, 2016) proposed the notion of equality of opportunity (EO), which is compatible with maximal accuracy when the target label is deterministic w...

Perovskite solar cells (PSCs) have substantially increased their power conversion efficiency (PCE) to more than 25% in recent years. However, the instability of these devices is still a strong obstacle for their commercial applications. Recently, all-inorganic PSCs based on CsPbI3 and CsPbI2Br as the perovskite layer have shown enhanced long-term s...

Structures involving a lattice and join-endomorphisms on it are ubiquitous in computer science. We study the cardinality of the set $\mathcal{E}(L)$ of all join-endomorphisms of a given finite lattice $L$. In particular, we show for $\mathbf{M}_n$, the discrete order of $n$ elements extended with top and bottom, $| \mathcal{E}(\mathbf{M}_n) | =n!\m...

Let $L$ be a distributive lattice and $\mathcal{E}(L)$ be the set of join endomorphisms of $L$. We consider the problem of finding $f \sqcap_{{\scriptsize \mathcal{E}(L)}} g$ given $L$ and $f,g\in \mathcal{E}(L)$ as inputs. (1) We show that it can be solved in time $O(n)$ where $n=| L |$. The previous upper bound was $O(n^2)$. (2) We characterize t...

Collecting and analyzing evolving longitudinal data has become a common practice. One possible approach to protect the users' privacy in this context is to use local differential privacy (LDP) protocols, which ensure the privacy protection of all users even in the case of a breach or data misuse. Existing LDP data collection protocols such as Googl...

An attacker can gain information of a user by analyzing its network traffic. The size of transferred data leaks information about the file being transferred or the service being used, and this is particularly revealing when the attacker has background knowledge about the files or services available for transfer. To prevent this, servers may pad the...

One of the main concerns about fairness in machine learning (ML) is that, in order to achieve it, one may have to trade off some accuracy. To overcome this issue, Hardt et al. proposed the notion of equality of opportunity (EO), which is compatible with maximal accuracy when the target label is deterministic with respect to the input features. In t...

It is crucial to consider the social and ethical consequences of AI and ML based decisions for the safe and acceptable use of these emerging technologies. Fairness, in particular, guarantees that the ML decisions do not result in discrimination against individuals or minorities. Identifying and measuring reliably fairness/discrimination is better a...

Let L be a distributive lattice and E(L) be the set of join endomorphisms of L. We consider the problem of finding f⊓E(L)g given L and f,g∈E(L) as inputs. (1) We show that it can be solved in time O(n) where n=|L|. The previous upper bound was O(n2). (2) We characterize the standard notion of distributed knowledge of a group as the greatest lower b...

One of the main concerns about fairness in machine learning (ML) is that, in order to achieve it, one may have to renounce to some accuracy. Having this trade-off in mind, Hardt et al. have proposed the notion of equal opportunities (EO), designed so as to be compatible with accuracy. In fact, it can be shown that if the source of input data is det...

All-inorganic perovskite solar cells (PSCs) with inverted p-i-n configuration have not yet reached the high efficiency achieved in the normal n-i-p architecture. However, the inverted all-inorganic PSC are more compatible with the fabrication of tandem solar cells. In this work, a theoretical study of all-inorganic PSCs with inverted structure ITO/...

The distribution, abundance, and conservation status of sea turtles in the Colombian Caribbean have been studied for more than five decades. Historical estimations from field sightings and interviews with fishermen provided information about the high number of nesting females of four species (Caretta caretta, Chelonia mydas, Eretmochelys imbricata,...

We present original solutions to four challenging mathematical puzzles. The first two are concerned with random processes. The first, here called The President’s Welfare Plan, can be reduced to computing, for arbitrary large values of n, the expected number of iterations of a program that increases a variable at random between 1 and n until exceeds...