Leonardo O. expert freelancer in Node.js, Java, Python, Ruby on Rails, Django

L. O.

developing with passion

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USD 20.00

IT & Programming

About me
More than 12 years developing corporate and robust web applications using JAVA/J2EE Oracle and Amazon Web Services2 and now working as freelancer with agile methologies,  Node.js/Express.js/MongoDB, Python/Django Ruby/Rails/Sinatra/DataMapper, MySQL and PostgreSQL
Work history
Period: 01/2013-07/2014
Company:     ACJ International (a leading marketer of proteins produced around the globe).
Position:     Applications Architect (hands on).
Tasks:         Establish software coding standards, repository management (GIT) and applications deployment procedures based on best practices.
Design and develop JAVA and PYTHON core components to improve and extend an existing FWK originally created by a third party company (KSAP) provider of AJC.
Work as technical liaison between AJC business analysts, developers, and third party providers as KSAP and Finder. 
Develop integration between Oracle OTM and legacy systems using PYTHON based webservice interfaces.
Deploy new application releases.
Quality control and validation of software artifacts developed by third party providers with code review and merging control.
Design using well-known design patterns.
Unit tests control and usage definitions (JUNIT).

Period:     07/2010-12/2013
Company:     OSDE (the biggest health care company in Argentina) as consultant for Softtek  (a world class IT consulting company).
Position:     JEE Architect, technical lead and agile developer.
Tasks:         Meet company business needs with best practices in software development and company methodologies and coding standards.
Create company value empowering the company business analysis capabilities thru BI tools.
Technical analysis, refactoring and scalability research for MIRA (a BI platform who provides to all company applications BI capabilities, easy integration and an IDE for BI Dashboards and dynamic or scheduled reports creation). Currently MIRA faces many challenges as the integration to the company’s ESB, portalization and clustering.
Design of software components (using UML in EA) for PRAGMA a Data Warehouse based solution used to control the company's medical cost and health care provider’s performance.
Mentoring and software development support to OSDE providers.
Quality control and validation of software artifacts developed by OSDE providers (with code review and merging             control).
Life cycle definition of process related to application improvement and repositories handling (maven, SVN).
WAR/EAR/DB scripts Building to productive Deploy.
Develop core and integration components using the Company's JEE Framework, best practices, Artifactory and SVN         repositories under scrum as development methodology.
Design using well-known design patterns.
Mentoring to new developers introducing them to the company's standards and development best practices.
Unit tests control and usage definitions (JUNIT).
QA team capacitation to use the testing tools SAHI and WATIR.
        Performance improvement in JAVA, DB2 and MS SQL software artifacts.
        Migration to a new and improved Company's framework based on ESB, SOA, Spring, Aspects, Hibernate, Struts 2,             Jasper Reports, MooTools and JQuery.

Period:     06/2012 -07/2012 (~ a month)
Company:     INDRA (a worldwide E-commerce & IT Outsourcing company).
Position:     Freelance/part time Node.js developer.
Tasks:     -Design and develop with distributed team and an aggressive scheduling: TouchSurvey a web based system for controlling vote using technologies like: Node.js Express.js, mongoose, MongoDB, socket.io, JSON, JQuery, nginx and IOS client devices using JSON with Node.js integrated servers.
-Design and develop new features for TouchSurvey as pictures and geolocations data registration, and a map based main dashboard to control the theatre of operations.

Period:     07/2009-07/2010
Company:     First Data International (First Data Cono Sur S.A. it is the unique licensed company in Argentina and Uruguay for MasterCard and Maestro brands)
Position:     Software Architect.
Tasks:         - Coding best practices documentation update.
- Design and development of critical/foundational application components using design patterns.
- Modeling diagrams of classes, sequences, activities, collaborations and deployments.
- Mentoring to new developers introducing them in Company’s standards and best practices for development.
- Organize the source code repositories (CVS/SVN) and define the script-based interaction with providers to integrate external and in-house developments.
- Unit test definition and control (JUNIT/JUNITEE).
- Definition and control of functional and stress tests using badboy/jmeter, the grinder and selenium.
- Components desing for a workflow based system used to control the provisioning of Posnet payment devices.
- Collaborate in the deployment and topology design for the company’s web applications.
- Auditory of software artifacts delivered by providers.
- Research about multi factor authentication methods to create a company’s security framework (grid cards, ldap and tokens).
- Reverse engineering to document applications ERDs using Enterprise Architect.
- Research and implementation of a SCM company’s methodology using Hudson, Maven, Cobertura and checkstile reports.
- Research and deployment of a Redmine-based solution to keep track of changes requests and issues for the company’s applications.
- Solve design issues related to extension, escalation, and performance.
- Creation and evaluation of architectural change proposals.
- Apply OWASP Top Teen recommendations and add Fortify 360 SCA usage as part of the development process.
- Use of technologies as: workflows JBPM, EJB 3.0, JSF, Hibernate, Spring and GRails.

Period:        01/2008-06/2009    
Company:    Verizon Business http://www.verizonbusiness.com a global Telco company (Argentina branch).
Area:        Global Provisioning System - Workflow.
Position:        Application Developer Consultant in JEE technology (hands on) in the company provisioning system workflow.
Tasks:        - Collaborate in Architectural changes in the provisioning workflow.
- Create guideline documentation related to best development practices and tips using Spring, JPA and Hibernate with queries to multiple schemas and cross DB.
- Lead a development team of 4 developers to refactor an application persistence layer, changing and normalizing many tables/entities and going from DB2 to ORACLE.
- Design and develop interacting with coworkers from USA and INDIA, and dealing with different timeframes.
Solve and follow up application defects interacting via conf. calls in a daily basis with managers from USA.

Period:        08/2006-12/2007    
Company:    IT Resources S.A. http://www.itrsa.com.ar Informatics specialized consulting (Capital Federal - Argentina).
Client:        Santander Rio S.A. (Argentina) project ABLI.
Position:        Team Leader as JEE Architect (hands on) for the project ABLI (a cash translation control application).
Tasks:        - An Architectural change starting with an old fashioned and obfuscated ad-hoc business logic based on a servlet piping(a kind of primitive Web Services), and ending with it’s replace for a more maintainable and less error prone business layer that properly integrates low level resources functionality (RACF, LDAP, CICS, MQ, persistence)
- Performance and stability improvement: The application was found with serious problems of performance and stability. All of them with root cause in the lack of design knowledge to; avoid DB connection leaks, have a proper resources exception handling, and retry mechanisms.
- Determine best practices in development, DB design and scripting, and help to spread them in the team.
- Apply and follow up the usage of a new company methodology standard for software development with a challenging and not so well documented legacy application. 
- Refactoring to improve the user session handling avoiding unnecessary data storage during all over the user session life and compromising in that way the server memory availability.
- Change in the configuration management to avoid previous configuration problems when the new versions in development are deployed on each ambient (DEV, SIT, UAT and PROD).
- Change ERD and DB Data Definitions in order to eliminate previous model vicious as transactional and configure data duplication, pour quality in error and auditory log.
- Source code improvement, by replacing the massive use of bad programming practices as System.out, printStackTrace and bad Exceptions handling.
-Implementation of a project repository with CVS in a UNIX server integrated with developer IDEs (previously they was working without a repository with serious problems of integration because this bad practice).
-Software code integration in the repository and deployments packages building.

Period:    05/2006-08/2006    
Company:    IT Resources S.A. http://www.itrsa.com.ar Informatics specialized consulting (Capital Federal - Argentina).
Client:        Telecom Argentina (one of the 2 biggest telco companies in Argentina)/ IBM Argentina project ARIES.
Position:        Senior Developer in J2EE / IBM MQ Workflow and IBM InterChange Server tools designer and developer.
Tasks:        - Business process modeling for the new corporate workflow.
- IBM MQ Series configuration and integration with IBM MQ Workflow to enable synchronous and asynchronous queued business process messages.
- Modeling and development of business objects and collaboration objects (with java invocations) for IBM InterChange Server.
- Development of a simulator based on java/JMS to simulate MQ workflow answers from InterChange Server.
- Migration of functionalities from IBM tools to BEA Weblogic Integration technology per corporate turn around decision.
- Use cases analysis and java components design based on design patterns.
- Use of Enterprise Architect for UML workflow modeling and documentation
- Building of test cases for the developed workflows.

Period:    10/2004-04/2006    
Company:    IT Resources S.A. http://www.itrsa.com.ar Informatics specialized consulting (Capital Federal - Argentina).
Client:        Citi Bank Latam Development center  (a developing and maintenance center for European and Latin-American home banking portals).
Position:        J2EE Web engineer. In this position it was critical the interaction in English with other professionals from USA, India and China.
Tasks:        - Home banking portal migration from a 2 tiers solution based on jsp pages (with business logic inside) and resource adapters to BEA Weblogic technology running on a Sun Solaris platform.
- Integration for already in place functionality responsible to show credit cards balances and located in Singapore servers with the local home banking portal of Citi Bank Argentina (http://www.citibank.com.ar).
- Collaborate with onshore (Fort Lauderdale, USA), and offshore (India and Singapore) coworkers and contractors dealing with different time frames.
- Use technologies as BEA Weblogic Portal, Integrator, JMS, EJB, Site Minder, Security Gateways, LDAP, iPlanet, JBuilder X, ORACLE, Cryptography APIs, use cases analysis, design patterns, UML and tools as Enterprise Architect.
- Building of test cases for the Citi Bank Argentina home banking portal.

Period:    10/2003-10/2004
Company:    CDA Informática S.A. ( http://www.cdainfo.com IT consultant company (Capital Federal) Argentina.
Client:        Siderar S.A. a company of Argentina part of the Techint group.
Position:    J2EE senior developer for one of the huge JAVA projects in Argentina the NCA project of Siderar S.A. This project required near to 300 professionals: 100 JAVA coders, 80 .NET coders, 6 DBA and many other Analysts, QA teams and QNX specialists and it was taken by ORACLE as a leading case.   
Tasks:        - Analyze using use cases, design part of the architecture and business logic in the back end tier using design patterns, UML, RUP, OC4J, EJB, XDOCLETS, HIBERNATE, distributed caches and transactions to work in a linux server cluster, design and develop of state machines to drive the production process, connectors and adapters for the multi tier architecture of the NCA project.
- Using of many software tools: Eclipse, JDeveloper, TOAD and Enterprise Architect for UML modeling.

Period:        03/2003-10/2003
Company:        IT Resources S.A. http://www.itrsa.com.ar IT consultant company partner of IBM (Capital Federal) Argentina.
Position:    J2EE Semi Senior.
Tasks:        - Use cases modeling, design, implementation and testing of B2B applications using J2EE technology (JSP, SERVLETS, EJB), Struts, XML, IFS IBM Framework, ORACLE, DB2, WEBSPHERE server and Visual Age for JAVA).
- Leading 4 professional resources for the Glaciar project of Consolidar S.A. a company of the BBV European bank.
Clients:        - Ford (automotive): Developing a system for tax refunds of imported and exported vehicle parts and components. There we used JSP, IFS IBM Framework, ORACLE, WEBSPHERE server, Visual Age and Erwin for data modeling.
        - La Caja (Insurance):  Developing a system to control Vehicles insurance. There we used JSP, IFS IBM Framework lite, IBM MQ Series and ORACLE Stored Procedures (with legacy business logic).
        - OSDE (healthcare):  Developing a web-based agenda to handle VIP Company’s contacts (using meta data concepts to obtain the needed flexibility in the application model). There we used JSP, Struts, DB2, a Websphere server running on a HP-UX platform and a LDAP log & signing integration via web services.        
- Consolidar/BBV Bank (banking): Leading the development of a web-based application (Glaciar project) to integrate the customer registration process for 5 business units. There we used JSP, Servlets, Struts, EJB, XML, Apache Digester, Remote Scripting for Web contents (similar to the actual AJAX but applet based), ORACLE Stored Procedures in a distributed data base environment (using DB links) and with distributed transaction.
- Sony(retail): Designing and Developing a sales and stock planning system for the Latin-American market. There we used JSP, Remote Scripting and ORACLE Stored Procedures.

Period:        04/2002-01/2003
Company:    I+D Informática s.c. Marbella, Málaga España (A company dedicated to sale 3rd party canned software, hardware and custom developed applications in standalone and web based solutions).
Position:    Analyst programmer and technical sales support.
Tasks:        - Developing of a Point of Sale terminal as a web based system based on JAVA technology and using JBUILDER
- Active Web sites creation and maintenance using technologies as PHP/MySQL, ASP/SQL SERVER and JSP/SERVLETS/JDBC.
            Web design using: Macromedia Flash, Corel Draw, Photoshop and Macromedia Dreamweaver.    

Period:        02/2000-03/2002
Company:        Informática el Corte Ingles IECISA (IBM partner in the retail sector) Argentina delegation (Buenos Aires).
Position:        Analyst programmer.
Tasks:        - Research new technologies in e-commerce.
        - Customer requirements acquisition, and use cases analysis.
        - Object Modeling and functional documentation elaboration.
- Development effort estimation.
- Work integrated with professionals from Telefónica Data de Argentina (one of the two biggest Telco companies in Argentina).
- Functional analysis and development of B2C solutions: e-Commerce, kiosk, wml, wap based sales and e-mailing sales.
- Migration from Windows to UNIX platform of an ANSI C and Pro C based e-Commerce solution.

Period:        04/1997-01/2000    
Company:    MACOM an institution with 3 small hospitals and a communitarian center and a Radio Fm.
Position:        Electronic technician and person in charge of all the IT systems in the institution.
Tasks:        Electric installations, telephonic installations (PBX wiring and programming, Installations of security systems as Alarms and CCTV and maintenance of many electro-medic equipments.
Development of an Intranet solution to connect the hospitals of the institution, and based on JAVA Servlet technology.
            Development of a system for clinical history administration, patient turns.
            Institutional website development.