Radu Rădescu

• PhD
• Professor (Full) at Universitatea Națională de Știință și Tehnologie Politehnica București

The idea from which this paper started is the interest for the learning part of the security elements of Office documents, but also the one related to the main vectors of infection of ordinary users. This field is constantly evolving and therefore learning to use any automated tool can be useful for both users and those who work actively with malwa...

This paper aims to perform a comparative analysis, based on experimental results obtained in practical tests, of the correlation that can be identified between a transform and an encoding algorithm for lossless compression of data from text files. At the same time, the paper offers the user the opportunity to test these concordance techniques, allo...

This paper highlights some ways in which people can book, in a very simple way, a promotional package of e-commerce in tourist services, without the need for face-to-face communication. The entire transaction is executed online, but also in a secure way, ensuring the real identity of both the buyer and the seller. Users will benefit from various of...

In the context in which the exchange of information between information systems is becoming increasingly important and it is increasingly difficult to maintain it efficiently and securely, it is essential that malicious action cannot be taken against it and that this exchange of information to be carried out in perfect safety. The identification an...

This paper proposes a web application that provides adaptive pen management for the activities within a university or an IT company, in order to facilitate the work of employees and to improve the learning and internal development process. The proposed system is focused on planning, organization and, last but not least, on improving performance. Te...

Deoarece foarte multe persoane nu iau contact cu centre wellness pentru îmbunătățirea sau conservarea calității sistemului locomotor și a sănătății până atunci când este neapărat necesar, acestea nu știu unde să apeleze și cum să procedeze pentru a ajunge la specialiști. Astfel, ideea acestei lucrări este realizarea unei aplicații Web care permite...

The present paper presents an e-learning application that studies the different ways of performing file compression and the performances obtained in synchronizing them in remote communications. Based on compression, one can estimate the differences between two files and calculate the minimum difference that must be transmitted over a network to syn...

This paper proposes a study on the online learning process of applying Delta transformation, Delta compression and remote file synchronization. The e-learning application was developed in the Matlab R2008b working environment and treats both Delta transformation and Delta compression. For Delta compression, the chosen implementation is original, wi...

The purpose of this paper is to describe the design of a Web application for the study of management for the activities of an IT company, in order to facilitate the work of the students in practice, the trainees and the employees, as well as to improve the process of internal development of human resources. The proposed system is focused on plannin...

In this paper we have set up a system to monitor certain vital parameters such as pulse and body temperature. The application thus developed displays the recorded values and measured sensor data is transmitted through wireless technologies to a mobile computing unit. The application uses a variety of IT systems, both hardware and software. In the f...

This paper is motivated by the possibility of developing a wide variety of applications and domains in which Unmanned Aerial Vehicles (UAVs) can be used globally for various purposes. UAVs are currently used by public administrations and security forces such as police, fire brigades, civil protection, research institutions, construction, and agricu...

The purpose of this paper is to develop a learning application for the management of banking processes and related databases, which can be used to model the business processes specific to the educational field in finance and banking (e-banking). The application has a general character and can be used to implement any kind of business process in the...

The present work involves the development of a learning model for the analysis of data from telecommunication and social networks for devices that make data sessions and voice calls, using Business Intelligence (BI) concepts and tools. The paper has a multi/interdisciplinary character, calling for e-learning, telecommunication, database, programmin...

The paper describes the development of an original Java application using a Google Glass device, a VGA-video converter and a DVR drive. The application was designed for educational purposes in the medical field, allowing real-time management of the information needed to facilitate the surgeon's activity during operations or consultations. Students...

This paper presents the design, development and implementation of an online system for completing the questionnaires for assessing a university student feedback, expressing their satisfaction to the educational context interactions involving academic activities. The main objectives of the platform are to guarantee anonymity student throughout the e...

The 3D-DCT is used in video compression when the applied basic principle is the correlation between adjacent pixels in a frame and the correlation between pixels from the same position in adjacent frames (temporal correlation). This principle uses the concept that a video sequence can be seen as a parallelepiped representing the entire video sequen...

In order to achieve the best and most relevant performance in the field of lossless data compression, but also in order to deepen and refine the results obtained by the type of data to which the compression and decompression operation is applied, this work focuses on compression using the Q-coder, which is a relatively new and less-used coder than...

E-environment is a platform that offers the potential to bring together data about protected areas around the world to form a unified management system. The e-environment platform can provide or receive rapid information through the use of information technology, which can lead to improved citizens' awareness, real-time data updates, increased invo...

The original contribution of this work consists in designing and implementing a video conversion application for different video formats with basic editing functions for multimedia e-learning platforms. The programming language chosen is C++, the user interface is implemented in QT, the video compression support and editing options are provided by...

This paper presents the design and software development of a multimedia application for creating original e-learning content for viewing and processing audio files using the MATLAB® programming environment. The purpose of the application is to build a practical multimedia lab work that facilitates the interpretation of audio signals and their basic...

The importance of remote learning systems has grown greatly over the last few years and is being used by more and more users both to specialize in a particular field and to gain knowledge from areas of great interest. The Easy-Learning platform, developed as an original e-learning research project within the Department of Applied Electronics and In...

The paper presents an original method of text transformation based on permutations with restrictions and elimination of repetitive letters within a word having the purpose of improving the performance of lossless compression algorithms, based on a new generated dictionary. The direct transformation algorithm and the reverse transformation algorithm...

The Fixed Constraints Transform (FCT) encodes the text based on a dictionary. This dictionary is used to accomplish the connections between the words in the text and their corresponding transforms. The dictionary is generated one time and it is saved in a binary form for a better word-indexing speed. This method is strictly designed for text compre...

This article aims to create a theoretical and practical support for video engineering through an e-learning editing and video compression application. The original contribution is a new perspective of learning the basic practical skills of video signal processing: representation, editing and compression. The e-learning content application has a mai...

In this paper we propose an online learning method for constructing and editing different types of UML diagrams, with details about their purpose and the technologies used to create the study application. It describes how to design and use the application and how to integrate it as an e-learning content in a virtual learning platform. The paper pre...

This paper proposes a solution built on the principles of e-democracy, based on Business Process Management. Its purpose is to reveal the features of this e-activity branch and corroborate them with the specific management processes to create a method for generating e-learning content. The WebRatio platform-based application refers to the democrati...

In order to simulate the online management of the real access system in an education and culture institution, a user-friendly web interface was designed using the latest IT technologies. Based on the analysis made in the case study of the Romanian National Museum of Art, the following needs were identified: to create an automated visitors registrat...

The present work describes the PPM – Prediction by Partial (string) Matching algorithm for lossless compression of text. It studies the procedure of extending the source alphabet for the PPM encoding in order to allow using of symbols not yet present in the source alphabet at the very beginning of the process of text encoding. The work describes th...

The Easy-Learning platform is a system of online education developed as an original product of the Department of Applied Electronics and Information Engineering from the University Politehnica of Bucharest. The platform has undergone many changes over the years, from a simple project and becoming a complex and efficient work in virtual learning env...

This paper presents a case study of designing and using an Internet Banking Web application. Its goal is the online learning of administration and deployment of a virtual e-banking system. The application is developed using a three-tier architecture using Apache, PHP and MySQL. The application has all the functionalities of an actual e-banking real...

The PPM (Prediction by Partial Matching) methods are applied before the lossless compression algorithms, as a preprocessing procedure for the text in order to use efficiently the redundancy. This paper presents 4 compression algorithms preceded by 3 different PPM methods. The compression ratio is studied in relation with the file size, its content,...

This paper proposes a web server architecture that contains an open-source e-learning platform dedicated to asynchronous activity and a platform dedicated to organizing webinars (Internet held seminars). It is also proposed a Google Apps implementation, using the web application suite offered by Google: Gmail, Google Docs, and Google Calendar. Gmai...

Information Technology can help to manage cultural heritage material, when it comes to historical, architectural, archaeological and natural sites. The management application focuses on studying historical sites with heritage buildings (objectives) to create an interactive learning application as part of a management system for historical sites, us...

This paper presents a design solution for creating e-learning content developed using multimedia tools and modern web technologies. The chosen case study refers to the set of laboratory work of an academic study subject by applying interactive multimedia content, treatment of animations, complex content formatting and creative graphic design. Thus,...

This article describes the development of a web interface of an application for archaeological management system (RM360) used in online education platforms for archeology, architecture and restoration. Being a heritage management application, the database is populated with the related historical, cultural and archaeological items (elements). The ap...

The described application achieved implementation of a platform for online management of an e-library, the virtual system requiring simple and efficient access in order to loan e-books. After analyzing the numerous advantages of electronic services, the aim was to implement an application that can give users access to a vast cultural and educationa...

This paper presents a methodology for creating dynamic web applications for archaeological management systems with applications in architecture and restoration. The dynamic nature of the application consists in the use of new technologies at partial loading the web page elements. Search results are displayed in real time and lists are populated wit...

Coding algorithms are generally aimed at minimizing the output code length encoding speed once the code has been designed. Moreover, most codes use a binary alphabet. This paper examines other issues related to coding, such as additional constraints imposed on the channel. Code generation will be considered where there is a limit on code words. Lim...

The Knowledge Discovery in Distributed Databases is the process of finding useful knowledge from mining data sets stored in real implementations of distributed databases. Distributed Databases represents a software system that allows a multitude of applications to access the data stored in local or remote databases. In this scenario, the distributi...

This paper aims to observe how one can apply fixed and probabilistic constraints on information sources and to emphasize the benefits obtained from this process for learning systems. Constraints applied may be both fixed, that are initially established with rigorous formulation, and probabilistic, in which case the process becomes an adaptive one,...

This paper presents an interactive e-learning solution for Android mobile platform as an app for managing archaeological and architectural sites useful to students in architecture, archaeology, restoration, history, surveying and civil engineering. The app connects to a web server and performs user authentication or registration to a database. Once...

This paper aims to present the steps, methods and technologies used to create the new management module of the automatic allocation of students' optional assignments for mid-term projects, homework and graduation thesis, using a virtual education system. The Easy-Learning platform provides a framework for any type of on-line or off-line activity in...

Coding algorithms are generally aimed at minimizing the output code length encoding speed once the code has been designed. Moreover, most codes use a binary alphabet. This paper examines other issues related to coding, such as additional constraints imposed on the channel. Code generation will be considered where there is a limit on code words. Lim...

The purpose of this paper is to present the process of designing and developing a dynamic interface for an archaeological management system, with advanced possibilities of viewing, adding and modifying standardized sheets, created at a certain place, based on the coordinates extracted from the map. The main goal of the paper is to present the conce...

The purpose of this paper is to present to creative manner of designing and implementing the backend and frontend of the interface for a complex learning system in architectural management, using advanced technologies: ASP.NET, HTML, CSS, JavaScript, jQuery, C#, AJAX and JASON. The resulting platform can be used as general template for creating too...

This paper describes the optimization project of the Easy-Learning platform, an original e-learning system, designed and developed since 2004 in the e-activities laboratory of the Applied Electronics and Information Engineering Department of the Polytechnic University in Bucharest. A variety of technologies have been used in this project: HTML5, CS...

This paper is a short overview of the Re-Pair algorithm, used in lossless data compression of text files, with contributions in improving the data structures and the space-time analysis. Re-Pair is combined with transforms and compared in terms of performance to other popular algorithms.

In this paper will be applied concepts like amortized complexity or self-adjustment to binary search trees. Motivation comes from the fact that the search trees have multiples drawbacks. It will be developed and analyzed the splay tree, a self-adjusting form of binary search trees.

This paper presents an original version of Splay Tree for lossless compression, a self-adjusting form of binary search trees. It is developed and analyzed in its new form, and then is compared in terms of text compression performance to other algorithms and transforms.

The present paper deals with the new Object-Relational Mapping tool introduced in the Easy Learning platform. Propel 1.5 is the latest version of Propel, one of the ORMs fully compatible with the Symfony Framework, and, in comparison with the older versions, it has drastically improved the way the Easy Learning platform can manipulate it’s database...

The present paper deals with the implementation of the security and confidentiality concepts in the Easy Learning platform. Being a complex application, with a large number of users that can be either visitors, students, tutors or administrators who can access different information regarding one another, in the context of e-learning it is necessary...

The present paper refers to the benefits provided in the lossless compression by using preprocessing methods in order to exploit better the re-dundancy of the source file. The following contributions represent a sequel of the work entitled ,,Transformed Methods Used in Lossless Compression of Text Files" [20], focusing on the Length-Index Preservin...

The present paper refers to the benefits provided in the lossless compression by using preprocessing methods in order to exploit better the redundancy of the source file. The following contributions represent a sequel of the work entitled,Transformed Methods Used in Lossless Compression of Text Files" [20], focusing on the Length-Index Preserving T...

eLearning enables a quick and always improvable interaction between the tutor (teacher) and the student (user), who can access information from any point. Interactivity is provided by the possibilities, which are virtually endless, of multimedia formats (combination of text, sound, still images and moving images, animation, etc.) combined with hype...

The present paper deals with the implementation of the security and confidentiality concepts in the Easy Learning platform. Being a complex application, with a large number of users that can be either visitors, students, tutors or administrators who can access different information regarding one another, in the context of eLearning it is necessary...

The present paper deals with the new Object-Relational Mapping tool introduced in the Easy Learning platform. Propel 1.5 is the latest version of Propel, one of the ORMs fully compatible with the Symfony Framework, and, in comparison with the older versions, it has drastically improved the way the Easy Learning platform can manipulate it's database...

The present paper deals with the methodology used to reinvent the Easy Learning platform, in order to facilitate the overall control of this e-learning system. The main goal was to increase the coherence in writing the code and in designing the database. Therefore, the programming errors are easy to detect and the flexibility of the platform module...

This paper presents a study of transforms method used in lossless text compression in order to preprocess the text by exploiting the inner redundancy of the source file. The transform methods are derived from the star (*) transform. LIPT, ILPT, NIT, and LIT applied to text files emphasize their positive effects on a set of test files picked up from...

This paper intends to present a common use archiver, made up following the dictionary technique and using the index archiving method. This archiver is useful in order to accomplish the lossless compression for any file types. The application can offer useful conclusions regarding the compression performances and the influence of the chosen dictiona...

This paper presents a study of transform methods used in loss-less text compression in order to preprocess the text by exploiting the inner redundancy of the source file. The transform methods are Burrows-Wheeler Transform (BWT, also known as Block Sorting), Star Transform and Length-Index Preserving Transform (LIPT). BWT converts the original bloc...

The objective of the ICompress tool is to study the compression behavior in real situations with large data sequences for images with limited number of colors. Because the existing standards do not offer enough flexibility, and the implementation of some compression and decompression routines for these standards would not differ very much from the...

This paper intends to present a common use archiver, made up following the dictionary technique and using the index archiving method as a simple and original procedure. The original contribution of the paper consists in the structure of the archived file and in the transformation of the dictionary codes into archived characters. This archiver is us...

This paper intends to present a common use archiver, made up following the dictionary technique. The original contribution of the paper resides in using the index archiving method. This archiver is useful in order to accomplish the lossless compression for any file types. The application can offer useful conclusions regarding the compression perfor...

Platforma de învăţământ electronic Easy-Learning, creată în cadrul Catedrei de Electronică Aplicată şi Ingineria Informaţiei din cadrul Universităţii "Politehnica" Bucureşti dispune de numeroase opţiuni în meniu, atât în varianta administratorului şi a tutorelui, cât şi în cea a utilizatorilor. Dintre acestea, articolul de faţă prezintă metodologia...

The present paper intends to analyze the methods of efficiency computing for a cache memory from a computer memory system. After describing the principles of a cache memory, the efficiency is introduced based on the two locality mechanisms: the space locality and the time locality. The efficiency is studied as a function of the cache memory capacit...

Easy Learning is a platform helpful for both students and tutors. Tutors can add their courses and other material, tests, grades and statistics that students can access from within the school or from home. The system gives students the opportunity to test their knowledge at the end of each class. The tests can contain 4 types of questions (exercise...

The present paper intends to analyze the methods of performance evaluation for the input-output system of a computer. The art of designing an input-output (I/O) system refers to finding the adequate parameters needed to fulfill the cost, interaction and diversity objectives of a device, and, in the same time, to avoid the diminution of the overall...

The present paper intends to analyze the methods to determine the reliability of the high RAID levels used in protecting the information stored on hard disk systems. After describing the principles of data distribution and redundancy, the levels 5 and 6, involved in reliability evaluation, are presented. The mathematical expression used in computin...

The present paper intends to comparatively analyze three different benchmark algorithms for testing the processor performance. The benchmark methodology for computer systems was always extremely diverse and it is based on several testing algorithms and comparison standards. After describing the concept and the purpose of a benchmark system, differe...

The present paper intends to comparatively analyze the performances of lossless data compression using Huffman-derived adaptive algorithms (Faller-Gallager-Knuth and Vitter) for different file types. Experimental results are obtained for sets of representative input data. The compression ratio and the cost parameters of the compression are calculat...

The present paper intends to comparatively analyze the performances of lossless data compression using LZW-derived algorithms (Yokoo 1, Yokoo 2 and Bentley-Sleator-Tarjan-Wei) for text files and image files. Experimental results are obtained for different sets of representative input data. The compression ratio and the compression time are calculat...

The present paper intends to comparatively analyze the performances of lossless data compression using Huffman-derived adaptive algorithms (Faller-Gallager-Knuth and Vitter) for text files, image files and executable files. Experimental results are obtained for different sets of representative input data. The compression ratio is calculated and the...

Într-o descriere cât mai simplã, platforma e-learning este un mediu software accesibil atât în mediul Intranet, cât și în mediul Internet, dar care restricționeazã accesul în interiorul sãu. Accesul se realizeazã cu ajutorul unui nume de utilizator și a unei parole, fiecare utilizator având diferite facilitãți, în funcție de drepturile acordate de...

The paper presents an original method of text transformation based on permutations with restrictions and elimination of repetitive letters within a word having the purpose of improving the performance of lossless compression algorithms, based on a new generated dictionary. The direct transformation algorithm and the reverse transformation algorithm...

In this article we discuss image file types and how to hide information in them. We present a set of methods for steganography implementation with mathematical and practical details, relating with the most representative steganography software products available at this moment.

The present paper intends to comparatively analyze the performances of lossless data compression using the RLC and LZW algorithms between a proposed application (a software compression tool named ICompress) and a set of classical standards (GIF) and file compressors (RAR). The purpose of developing the ICompress program was to study the results of...

This paper proposes a modality of design for the on-line completion forms used on Web pages. The chosen example is based on the technical and educational analysis for a study application conceived in Flash programming language using the advanced level of facilities offered by ActionScript. In this approach the connection between a swf Flash file an...

The present paper intends to comparatively analyse a set of multicast Internet transmission protocols, emphasizing their advantages over the unicast protocols. The features of the multicast standard model are described, followed by the presentation of functioning principles of some routing protocols: distance vectors protocols, independent (sparse...

The present paper intends to present a professional method of developing software applications, based on visual modeling. The proposed methodology is not unique, but it is, at least, one of the best of the moment, taking into account the following considerations: • it is based on a standard modeling language; • it was adopted by many major companie...

A simple method to reduce the speckle in the multichannel SAR images consists in channel summation. Developed, originally, for the multi-look treatment, this method may be used also for other multi-channel images, if features' integrity is not a first concern. In the case of the multi-temporal sets, the channel summation leads, usually, to a non-un...

Any despeckling method for SAR images is a trade-off between speckle reduction level and preservation of image resolution. The Time-Space Filter (TSF) proposed by Colt$80uc et al. (2000), despeckles the multi-temporal SAR images while preserving the radar reflectivity, the textures and the edge contrast. The price paid for this feature integrity is...

Cet algorithme propose d’utiliser un résultat important de la théorie du traitement de signal dans la situation particulière où on doit établir la valeur du pas d’échantillonnage pour le prélèvement systématique dans le domaine de l’estimation statistisue. Il s’agit d’un premier pas dans les méthodes statistiques pour déterminer les caractéristique...

This paper describes the structure of the graphic format files GIF and JPEG used for digital storage of black-and-white and color images. It is also presented a comparison of performances between the two graphic format files, based on their main features. A set of recommended applications of these files for different types of images is included, ta...

This paper proposes a method of construction for data translation codes using a look-up table (LUT) dictionary. These codes are used for binary RLL constraint channels. It is studied the case of constraints for one symbol of the binary channel. Based on back-tracking algorithm, it is developed an iterative technique to obtain the channel sequences...

This paper proposes an overview to lossless data compression, making a comparison of classical algorithms performances for different types of files. These adaptive algorithms are used to store efficiently digital information. The paper offers a synthesis in this area, intending to provide a solid information set in data compression for information...

This paper presents a combined source-channel coding system corresponding to a universal source encoder and a data transmission encoder. The method is described for a binary symmetric Markov source (BSMS) and a binary symmetric channel (BSC) using the maximum a posteriori (MAP) detection. Convolutional codes are used for channel coding in order to...

This paper proposes a method of construction for data translation codes using a look-up table (LUT) dictionary. These codes are used for binary RLL constraint channels. It is studied the general case of constraints for both symbols of the binary channel. Based on the backtracking algorithm, it is developed an iterative combinatorial technique to ob...

This paper presents an object oriented approach for the software implementation of an algebraic-geometric decoder for Reed-Solomon codes based on a decoding procedure that is a generalization of Peterson’s decoding procedure for the BCH codes.

In the case of the transmission of vector quantized data, the codebook of the vector quantizer and the communication system are usually designed separately. This approach offers no possibility to improve the RMSE of the received data. The performances of the quantizer can be improved by using a mapping between the codebook of the quantizer and the...

The combination of DIT - a broadcast communication protocol - and Reed-Solomon code - burst error detecting and correcting code - could be efficient especially in the case of image transmission. Detection and correction of errors occurred on communication channel is accomplished in a software implementation of the protocol using the properties of R...

This is an original paper that presents a possible implementation of the encoding-decoding process for Reed-Solomon code. It is applied for error control in computer systems (mainframes) using a hypersystolic architecture. A software HRSD simulator was developed based on parallelism, high speed, and low complexity. This software simulator works for...

This original paper proposes a construction method for data translation codes using a look-up table (LUT) dictionary. These codes are used for binary RLL constraint channels. It is studied the general case of constraints for both symbols of the binary channel. Based on the backtracking algorithm, an iterative technique to obtain the channel sequenc...

This is an original paper dealing with the combination of DIT - a broadcast communication protocol - and Reed-Solomon code - burst error detecting and correcting code. This could be efficient especially in the case of image transmission. Detection and correction of errors occurred on communication channel is accomplished in a software implementatio...