Bird Song Alert for Forests

Adda Avendaño

Faced with the need to develop new alternatives for transmitting information without being detected by invaders of protected areas, Ariadna Isabel Rodríguez Gómez, a graduate of the Master of Science in Computer Engineering at the Centro de Investigación en Computación (CIC), designed a mathematical model of a sensor network for communication, through modified audio signals, capable of transmitting alert information with birdsong.

Illegal logging or species theft are the main drivers of deforestation, habitat destruction, and the consequent extinction of species worldwide. To combat illegal logging and extraction of natural and forest resources, campaigns are being promoted for reporting and monitoring, both in person and remotely, with systems that work through technologies such as radiofrequency or WiFi, which depend on a wireless connection that can be tapped or even deactivated.

Sound Waves as a Transmitting Medium

The transmission of information via radio frequency has expanded in recent years, due to the need to have information available everywhere and at all times.

However, one of its weaknesses is the lack of visibility known as "wireless blind spots", which cyber attackers take advantage of to tap into the signals.

Therefore, the polytechnic graduate designed a model that uses sound waves as a transmitter medium, which considers the use of steganographic techniques in a proposed algorithm to hide information within digital files to generate a hidden communication channel.

"What we did was to modify a recording of a bird's song to insert information, so that the alert data entered is imperceptible, so only the user who has the proposed algorithm will be able to separate the data.

On the one hand, the alert information, and on the other hand, the original song of the bird. This user would be the entity designated to protect the area," explained Ariadna Rodríguez.

Cyberattackers are capable of "dropping" radio frequency communications, which are usually commercial nodes. The use of this design will prevent this type of intervention since sound is used as a means of transmission between small nodes, so as not to be easily detected.

By analyzing the components of the birds' songs, the recordings were modified, including the pauses of the birds' songs, so that their reproduction is as close as possible to the originals.

Mathematical Model Development

With the advice of professors Gina Gallegos García and Mario Eduardo Rivero Ángeles, from CIC's Cybersecurity Laboratory and Network and Data Science Laboratory, respectively, as well as signal processing expert Izlian Yolanda Orea Flores, from the Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas (UPIITA), then Master's student Ariadna Rodríguez, conducted state-of-the-art research in search of advances in bio-inspired audio communications.

Most of the works are developed in aquatic environments, such as whales, dolphins, or sea lions. In the terrestrial environment, he only found one work that uses cricket chirping, but focused on military use, without determining the number of nodes needed for the communication network. So his project turns out to be an innovation in this field. To develop the mathematical model, as much information as possible was added, without making the changes in the birds' songs perceptible. The nodes that capture and transmit the signal from one to another are only turned on at that moment and are turned off during the silent periods, to extend the battery life for a longer period.

The Master of Science in Computer Engineering explained that a mathematical model is an abstraction through which the appropriate operating parameters can be obtained, including the number of nodes to be used, the characteristics of the data signals, energy savings, and details for a specific scenario, which in this case are the sensor networks that have the particular objective of transmitting bird song alert information.

With the paper "Modelado Matemático de una Red de Sensores para la Comunicación a través de Audios Modificados with Steganographic Techniques", Ariadna Isabel Rodríguez Gómez, obtained her Master's Degree in Science in Engineering, from the Centro de Investigación en Cómputación, with honorable mention Cum Laude.