Carlos Eduardo Castaño Ríos

Experimental multiplexing of encrypted movies using a JTC architecture

We present the first experimental technique to encrypt a movie under a joint transform correlator architecture. We also extend the method to multiplex several movies in a single package. We use a Mach-Zehnder interferometer to encrypt experimentally each movie. One arm of the interferometer is the joint transform correlator and the other arm is the reference wave. We include the complete description of the procedure along with experimental results supporting the proposal.

Master key generation to avoid the use of an external reference wave in an experimental JTC encrypting architecture

In experimental optodigital encrypting architectures, the use of a reference wave is essential. In this contribution, we present an experimental alternative to avoid the reference wave during the encrypting procedure in a joint transform correlator architecture by introducing the concept of a master key. Besides, the master key represents an additional security element for the entire protocol. In our method, the master key is holographically processed and used during the encryption process with the encrypting key. We give the mathematical description for the process in case of a single input object and then we extend it to multiple input objects. We present the experimental demonstration of the proposed method including two examples where this technique is successfully applied for several input objects.

Evolución de la contaduría pública en el municipio de Sincelejo-Sucre (1966-2017)

espanolCon el objetivo de describir el desarrollo historico de las practicas contables en Sincelejo –Sucre, se realizo una entrevista a siete contadores publicos del municipio de Sincelejo que tuviesen suficiente experiencia para abordar el analisis del periodo 1966 a 2017. Este trabajo se complemento con la revision de documentos historicos de la contabilidad en el municipio y el estudio de las instituciones universitarias donde se formaron los primeros contadores profesionales del municipio. Se destaca a la Universidad CECAR como pionera en la formacion de contadores publicos de la ciudad y region, la fuerte y rapida evolucion de las tecnologias de la informacion para procesar datos contables, en especial, desde los anos 90 en adelante, las dificultades para afrontar tantos cambios en la regulacion contable y el importante desarrollo de la contabilidad en el municipio gracias a la constitucion de nuevas empresas en actividades principalmente ganaderas y agricolas. EnglishThe principal aim of this research to describe the historical development of accounting practices in Sincelejo -Sucre, an interview was conducted with seven public accountants from the city of Sincelejo who had sufficient experience to deal with the analysis of the period from 1966 to 2017. This work was complemented by the review of historical accounting documents in the city and study of the university institutions where the first professional accountants of the city were formed. CECAR University stands out as a pioneer in the training of public accountants in the city and region, the strong and rapid evolution of information technologies to process accounting data, especially from the 90s onwards, the difficulties to face so many changes in accounting regulation and the important development of accounting in the city thanks to the formation of new companies in activities mainly cattle raising and agriculture.

Evaluación del desempeño de las cooperativas de ahorro y crédito de antioquia para el periodo 2009-2013

The aim of this paper is to present a financial assessment of the Antioquia cooperatives during the period 2009-2013. We conducted a study in the indicated period analyzed above the financial results of the Antioquia cooperatives. These analyzes were supported on information reported to the Superintendency Solidarity. Among the most important obtained results emerge, it is evident that the credit union smaller have more flexibility in the market and that therefore, its performance has been better than larger ones.

Análisis del desempeño financiero por regiones de Colombia 2009- 2012: un enfoque de evaluación de competitividad territorial

El objetivo de este articulo es presentar la evaluacion del desempeno financiero empresarial por regiones en Colombia para el periodo 2009-2012, a partir del analisis financiero integral, con un enfoque desde la competitividad territorial. Se utilizo la informacion financiera reportada ante la Superintendencia de Sociedades, la cual se clasifico en las cinco grandes regiones del pais. Se encontro que la region amazonica tiene dificultades para obtener financiamiento a largo plazo; en la zona andina el EBITDA es mas alto y hay mayor capacidad de generacion de efectivo, y por ultimo, el Caribe presenta el mayor ciclo operacional y la mas baja rentabilidad, lo que afecta su competitividad.

Subsampling technique to enhance the decoded output of JTC encrypting system

Optical systems have physical restrictions that impose limits in the finest spatial feature that can be processed. In this work we combine a subsampling procedure with a multiplexing technique to overtake the limit on the information that is processed in a JTC encryption system. In the process the object is divided in subsamples and each subsample is encrypted separately. Then the encrypted subsamples are multiplexed. The encryption of the subsamples is performed in a real optical JTC encrypting system. The multiplexing and the decryption process are carried out by means of a virtual optical system. Experimental results are presented to show the validity of the proposal.