Technical articles and research notes from ACRR, an independent research and technical publishing platform.https://acrr.asiaenhttps://acrr.asia/blog/token-based-authenticationhttps://acrr.asia/blog/token-based-authenticationA practical, end-to-end guide to HTTP fundamentals, token types, JWT validation, OAuth 2.0, OpenID Connect, refresh tokens, security controls, and ASP.NET Core.Mon, 12 Oct 2026 00:00:00 GMTComputing SystemsauthenticationauthorizationHTTPJWTOAuth 2.0OpenID ConnectASP.NET Corehttps://acrr.asia/blog/introduction-to-control-systemshttps://acrr.asia/blog/introduction-to-control-systemsAn introductory overview of feedback and system behavior.Sun, 11 Oct 2026 00:00:00 GMTRobotics and Controlcontrol-theoryengineeringhttps://acrr.asia/blog/numerical-integration-noteshttps://acrr.asia/blog/numerical-integration-notesExplicit Euler versus fourth-order Runge-Kutta on a test equation, and why accuracy and stability are separate questions.Sun, 04 Oct 2026 00:00:00 GMTMathematical Foundationsnumerical-methodssimulationengineeringhttps://acrr.asia/blog/state-space-models-primerhttps://acrr.asia/blog/state-space-models-primerWriting a mechanical system in state-space form, and reading its stability from the eigenvalues of one matrix.Sun, 27 Sep 2026 00:00:00 GMTRobotics and Controlcontrol-theorystate-spacelinear-systemshttps://acrr.asia/blog/feedback-and-system-behaviorhttps://acrr.asia/blog/feedback-and-system-behaviorHow closing the loop changes the speed of a simple first-order system and how sensitive its output is to plant errors and disturbances, checked with a short simulation.Sun, 20 Sep 2026 00:00:00 GMTRobotics and Controlcontrol-theoryfeedbackengineering