Responsible for modernizing a big legacy internal system that encompassed an Order Management System, a Client Management system, and a Reporting system, all of which were built using Microsoft Classic ASP technology. My duties included designing and implementing a classic 3-layer architecture, including the front-end, the server-side, and the datalayer upon existing Microsoft SQL Server databases and code. My work on this project helped to modernize and optimize the system, improving efficiency and productivity across all three areas of the application (ASP.NET Core, ADO.NET, C#, SignalR, HTML5, Javascript, JSON, T-SQL)

Responsible for analysis, architecture and team leading for a new web platform for managing and displaying online content for Antenna TV channel. Development was based on the eMentor CMS platform using Microsoft technologies (.ΝΕΤ 4.5, C#, Entity Framework, LINQ, SOA, ASP.NET Web Forms, SQL Server 2014, IIS8, Azure, Akamai, oAuth, Adman). The system provided automatic creation of mini-portals, cloud-based storage (videos) categorized in shows, seasons & episodes, online content search, video on demand, live streaming and more. It was the daily routine of the backend content team that was supporting the web portal. (The system has been decommissioned after arround 2 years of service)

WiPLUS HOTSPOTResponsible for design, architecture and implementation a centralized control system for providing Wi-Fi internet access via prepaid cards. The service, called WiPLUS Hotspot, was installed in public places (hotels, businesses, large shopping centers, beaches, etc.) and wherever there was need for prepaid Wi-Fi internet access. The system consists of the following 1. A central server (WiPLUS Server) that implements authentication, authorization and accounting (AAA) services. For the implementation of the triple-A server, the following Microsoft technologies were used: .NET Framework, IIS7.5, SQL Server 2008, C #, ASP.NET Web Forms, jQuery, SOA2. Local servers called Hotspot Servers that implemented the network communication portion of the service. Hotspot servers were developed with Debian Linux, C/C++ programming language, shell script and IP tables.3. The system was also accompanied by managed access point devices for which OpenWRT custom firmware was created and a C-based client application for control by the local Hotspot Servers.

-eMentor CMS PlatformΡesponsible for the analysis, design, and implementation of the content management and portal management platform for GreekGeeks, which is abbreviated as eMentor. The platform incorporated elements from more expensive CMS systems like Vignette and SharePortal Server, offering simpler abstractions, easier management, and exceptional speed. Additionally, it served as the Application Framework for all the company's projects, including portals, collaboration systems, e-commerce, and more.Technologically, it was a web-based multi-tier system entirely based on the .Net framework 3.5 (C#, SOA, ASP.Net Web forms, ADO.NET, WCF, jQuery, AJAX). It supported multiple RDBMS (e.g., MySQL, SQL Server) and featured a modern client API accessible through web services (WCF). The system was supported by three (3) Windows services for content distribution, full-text search, and workflows.The eMentor Portal Server was designed as an extension of the ASP.NET pipeline (implemented through custom HttpModules, HttpApplication, PageHandlerFactories, etc.), allowing a website to be served entirely dynamically, without the existence of physical pages on the filesystem.Some of the portals that had been implemented using this infrastructure are as follows:http://www.hellenicparliament.gr, http://www.aia.gr, http://www.fthis.gr, https://www.atlanticahotels.com/-eMentor - eShopDesign and implementation of an e-commerce platform built on top of the eMentor platform. eMentor was used as the application framework and ORM, with the goal of creating an e-shop platform that met the high-end standards of the market at the time. Installations of this platform included www.brandsgalaxy.gr, http://www.greekbooks.gr/, http://www.artfloor.com/en/, and https://www.funkydrop.gr/-R&D of a prototype Greek Lemmatizer for use with Apache Lucene.NET (C#). It forms the core of the search service for eMentor

-Analysis, design and development of a custom distributed system for access control and time attendance. In addition, the system is capable of calculating payment data for the Organization’s employees. The system uses SQL Server 7/2K as the data repository. It includes modules for custom replication between the various nodes of the system (Win32 API + ODBC API). It has a main module that communicates (RS 485) with the hardware (SAHO SC-202A) and takes the in-out clocks from the employees and sends them to the RDBMS (a multithreaded win32 app). In addition, the calculation machine is implemented as a dynamic link library so as its services to be possible to used by the back office module, which is implemented with Delphi.-Revised a version of the above system implemented using the .NET Framework. The new design added new functionality for the spatial representation of the secured areas (buildings). Also added several new abstraction levels in order the new system to be capable to talk with new access control hardware (ΚΑΒΑ). This new product is currently deployed and is used in several important Organizations.

Responsible for various complex technological solutions in Windows environments primarily for the public sector. The following are the two primary projects as a Unisoft Employee: Ministry Of Transports and Communications (KTEO) Analysis, design and development of a complex information system consisting of various modules, which include apps for RF/Batch communication between portable DOS-compatible terminals with ORACLE RDBMS and communication between vehicle check lines and gas analyzers with ORACLE RDBMS. Development of a multithreaded TCP/IP Application Server as Windows NT service, integration with ORACLE RDBMS via OCI API. In addition, the system contains various support modules (Tracer app for testing the communications, Service Control Manager for the Application Server etc). Development of Dos-compatible Client applications for the two types of portable terminals: RF terminals and Batch terminals (communication via cradle – RS232). Ministry of AgricultureAnalysis, design and development for the intranet of the involved research institutes (ETHIAGE, Ministry) of a custom data presentation web application. The data have to do with meteorological and climatologically qualities. The web application via a rich UI permits user to choose a region of Greece and as a second step to choose a meteorological station to view the related data. It shows data of the last fifteen (15) days using bar graphs or line graphs. The graphs are generated via JavaScript at the client’s web browser. For the implementation of the system, ISAPI technology was used to build an IIS extension library and ODBC API to communicate with the database (SQL Server). For the Data presentation layer used DHTML, JavaScript, CSS and VML.

Supervised, designed and implemented custom warehouse systems for inventory control, order picking and taking over. The solutions were implemented for portable DOS-compatible terminals. The following are a few mine projects as a Datalex employee:Kotsovolos AEVESupervision design and implementation of a custom warehouse system for inventory control, order picking and taking over. The solution was implemented for portable Dos-compatible terminals. The interesting point of the system is the ability of the terminals, to connect and login to the mainframe of the company (HP-Unix) to exchange data files, remotely. (Datalex S.A.). Minos EMISupervision design and implementation of a custom system to assist their logistics flow in their main warehouse. Cooperation of the new custom system with their legacy information system running in AS-400. (Datalex S.A.).Ilen FashionSupervision design and implementation of a full-fledged warehouse management system, with portable Dos-terminals bearing radio frequency cards to communicate with the company’s LAN (RF terminals). Integration with the preexisting legacy system. (Datalex S.A.).